Note: Descriptions are shown in the official language in which they were submitted.
TRACK SYSTEM FOR TRACTION OF A VEHICLE
FIELD
The invention relates generally to track systems for traction of vehicles such
as
snowmobiles, all-terrain vehicles (ATVs), and other off-road vehicles.
BACKGROUND
Certain vehicles may be equipped with track systems which enhance their
traction and
floatation on soft, slippery and/or irregular grounds (e.g., snow, ice, soil,
mud, sand,
etc.) on which they operate.
For example, snowmobiles allow efficient travel on snowy and in some cases icy
grounds. A snowmobile comprises a track system which engages the ground to
provide
traction. The track system comprises a track-engaging assembly and a track
that moves
around the track-engaging assembly and engages the ground to generate
traction. The
track typically comprises an elastomeric body in which are embedded certain
reinforcements, such as transversal stiffening rods providing transversal
rigidity to the
track, longitudinal cables providing tensional strength, and/or fabric layers.
The track-
engaging assembly comprises wheels and in some cases slide rails around which
the
track is driven.
A snowmobile, including its track system, may face a number of challenges
while riding.
For example, the track system may generate noise that can be significant
(e.g., for a
rider and/or the snowmobile's environment), the track may be exposed to
factors (e.g.,
snow conditions, ground unevenness, etc.) that affect its traction and/or
floatation
and/or cause wear, etc.
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Similar considerations may arise for track systems of other types of off-road
vehicles
(e.g., all-terrain vehicles (ATVs), agricultural vehicles, or other vehicles
that travel on
uneven grounds) in certain situations.
For these and other reasons, there is a need to improve track systems for
traction of
vehicles.
SUMMARY
In accordance with various aspects of the invention, there is provided a track
system for
traction of a vehicle. The track system comprises a track and a track-engaging
assembly for driving and guiding the track around the track-engaging assembly.
The
track system may have features to enhance its traction, floatation, and/or
other aspects
of its performance, including the track that may comprise reinforcing material
(e.g.,
reinforcing polymeric material) that is stronger (e.g., stiffer, harder,
and/or more
resistant to wear) than elastomeric material of the track, such as to improve
rigidity
characteristics of the track, reduce noise generated by the track system,
improve a
resistance to wear (e.g., to cutting, chipping, chunking, cracking and/or
tearing) of the
track, enhance heat management (e.g., improve heat dissipation or reduce heat
build-
up) within the track, and/or reduce a weight of the track. The reinforcing
material may be
provided as one or more thin layers constituting at least part (e.g., of a
periphery) of one
or more components of the track (e.g., a carcass, traction projections, and/or
drive/guide lugs).
For example, in accordance with an aspect, there is provided a track for
traction of a
vehicle. The track is mountable around a plurality of wheels. The track
comprises a
ground-engaging outer surface and an inner surface opposite to the ground-
engaging
outer surface. The track comprises elastomeric material allowing the track to
flex around
the wheels and reinforcing material stronger than the elastomeric material and
constituting at least part of a periphery of the track.
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In accordance with another aspect, there is provided a track for traction of a
vehicle.
The track is mountable around a plurality of wheels. The track comprises a
ground-
engaging outer surface and an inner surface opposite to the ground-engaging
outer
surface. The track comprises elastomeric material allowing the track to flex
around the
wheels and ultra-high-molecular-weight polyethylene constituting at least part
of a
periphery of the track.
In accordance with another aspect, there is provided a track for traction of a
vehicle.
The track is mountable about a plurality of wheels. The track is elastomeric
to flex
around the wheels. The track comprises a ground-engaging outer surface, an
inner
surface opposite to the ground-engaging outer surface, and a plurality of
traction
projections that project from the ground-engaging outer surface. The track
comprises a
first elastomeric material and a second elastomeric material overlying the
first
elastomeric material. The second elastomeric material constitutes at least
part of a
periphery of the track and includes an elastomeric matrix and reinforcing
particles
embedded in the elastomeric matrix.
In accordance with another aspect, there is provided a track for traction of a
vehicle.
The track is mountable about a plurality of wheels. The track is elastomeric
to flex
around the wheels. The track comprises a ground-engaging outer surface, an
inner
surface opposite to the ground-engaging outer surface, and a plurality of
traction
projections that project from the ground-engaging outer surface. The track
comprises a
first elastomeric material and a second elastomeric material adjacent to the
first
elastomeric material. The second elastomeric material includes an elastomeric
matrix
and reinforcing particles embedded in the elastomeric matrix.
In accordance with another aspect, there is provided a track for traction of a
vehicle.
The track is mountable about a plurality of wheels. The track is elastomeric
to flex
around the wheels. The track comprises a ground-engaging outer surface, an
inner
surface opposite to the ground-engaging outer surface, and a plurality of
traction
projections projecting from the ground-engaging outer surface. The track
comprises: an
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elastomeric material; and a plurality of reinforcing segments that are spaced
from one
another in a longitudinal direction of the track, constitute at least part of
a periphery of
the track, and include reinforcing material stronger than the elastomeric
material.
These and other aspects of the invention will now become apparent to those of
ordinary
skill in the art upon review of the following description of embodiments of
the invention
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
A detailed description of embodiments of the invention is provided below, by
way of
example only, with reference to the accompanying drawings, in which:
Figure 1 shows an example of a vehicle comprising a track system in accordance
with
an embodiment of the invention, in which the vehicle is a snowmobile;
Figure 2 shows a side view of the track system;
Figure 3 shows a perspective view of a track-engaging assembly of the track
system;
Figures 4 to 7 respectively show a perspective view, a plan view, an elevation
view, and
a longitudinal cross-sectional view of part of a track of the track system;
Figure 8 shows a reinforcing material of the track overlying an elastomeric
material of
the track;
Figure 9A shows a widthwise cross-sectional view of part of the track;
Figure 9B shows a widthwise cross-sectional view of part of the track in
accordance to
another embodiment;
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Figures 10 shows a layer of reinforcing polymeric material of the reinforcing
material of
the track constituting at least part of a ground-engaging outer surface of a
carcass of
the track;
Figure 11 shows a layer of reinforcing polymeric material of the reinforcing
material of
the track constituting at least part of an inner surface of the carcass of the
track;
Figure 12 shows the layer of reinforcing polymeric material of Figure 11 in
accordance
with an embodiment in which it includes a plurality of segments that are
spaced apart
from one another;
Figure 13 shows a side elevation view of a rail of the track-engaging assembly
of the
track system;
Figures 14A to 14C show other embodiments in which the reinforcing material of
the
track comprises a layer of reinforcing polymeric material constituting at
least part of the
ground-engaging outer surface of the carcass and a layer of reinforcing
polymeric
material constituting at least part of the inner surface of the carcass;
Figure 15 shows a perspective view of a traction projection of the track where
a layer of
reinforcing polymeric material of the reinforcing material of the track
constitutes at least
part of a rear surface of the traction projection;
Figure 16 shows a cross-sectional view of the traction projection as indicated
in Figure
15;
Figure 17 shows a perspective view of the traction projection of the track in
accordance
with another embodiment in which a layer of reinforcing polymeric material
that
constitutes at least part of the rear surface of the traction projection
includes a plurality
of segments spaced apart from one another;
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Figure 18 shows a perspective view of the traction projection of the track in
accordance
with another embodiment in which a layer of reinforcing polymeric material of
the
reinforcing material of the track constitutes at least part of a front surface
of the traction
projection;
Figure 19 shows a cross-sectional view of the traction projection as indicated
in Figure
18;
Figure 20 shows a perspective view of the traction projection of the track in
accordance
with another embodiment in which a layer of reinforcing polymeric material
that
constitutes at least part of the front surface of the traction projection
includes a plurality
of segment spaced apart from one another;
Figure 21 shows a longitudinal cross-sectional view of the traction projection
of the track
in accordance with another embodiment in which the reinforcing material of the
track
comprises a layer of reinforcing polymeric material constituting at least part
of the front
surface of the traction projection and a layer of reinforcing polymeric
material
constituting at least part of the rear surface of the traction projection;
Figure 22 shows a longitudinal cross-sectional view of the traction projection
of the track
in accordance with another embodiment in which the reinforcing material of the
track
comprises a layer of reinforcing polymeric material constituting at least part
of a tip of
the traction projection;
Figure 23 shows a longitudinal cross-sectional view of the traction projection
of the track
in accordance with another embodiment in which the reinforcing material of the
track
comprises a layer of reinforcing polymeric material constituting at least part
of the front
surface of the traction projection, a layer of reinforcing polymeric material
constitutes at
least part of the rear surface of the traction projection and a layer of
reinforcing
polymeric material constitutes at least part of the tip of the traction
projection;
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Figure 24 shows a widthwise cross-sectional view of the traction projection of
the track
in accordance with another embodiment in which the reinforcing material of the
track
constitutes an entirety of the periphery of the traction projection;
Figures 25 and 26 show a longitudinal and a widthwise cross-sectional view of
a
drive/guide lug of the track in accordance in an embodiment in which the
reinforcing
material of the track constitutes at least part of a periphery of the
drive/guide lug;
Figure 27 shows an example of an embodiment in which the reinforcing material
of the
track is bonded to a portion of an elastomeric material of the track before
molding of the
track;
Figure 28 an example of an embodiment in which the elastomeric material of the
track is
loaded with particles of reinforcing fabric material;
Figure 29 shows an example of an embodiment in which the reinforcing material
of the
track includes a plurality of layers of reinforcing polymeric material that
are adjacent to
one another;
Figure 30 shows an example of an embodiment in which the reinforcing material
of the
track includes a plurality of layers of reinforcing polymeric material that
are spaced apart
from one another;
Figure 31 shows an example of an embodiment in which the reinforcing material
of the
track constitutes at least part of a reinforcement embedded in the carcass of
the track
and selected drive/guide lugs of the track;
Figure 32 shows an example of an embodiment in which the reinforcing material
of the
track constitutes at least part of a reinforcement embedded in the carcass of
the track
and selected traction projections of the track;
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Figures 33 to 36 show an example of an all-terrain vehicle (ATV) comprising
track
systems in accordance with another embodiment of the invention, instead of
being
equipped with ground-engaging wheels;
Figures 37 and 38 show an example of a snow bike comprising a track system in
accordance with another embodiment of the invention, instead of being equipped
with a
rear wheel;
Figure 39 shows an example of another embodiment in which the traction
projections of
the track comprise columns;
Figure 40 shows a graph of test data evaluating noise generated at given
speeds by a
conventional track compared to the track of Figure 10;
Figure 41 shows an example of a variant in which the reinforcing material
includes a
polymeric matrix loaded with reinforcing particles disposed on a portion of
the
elastomeric material of the track;
Figure 42 shows an example of a variant in which the reinforcing material,
including a
polymeric matrix loaded with reinforcing particles, of the track overlies an
elastomeric
material of the track;
Figure 43 shows an example of a variant in which a layer of the reinforcing
polymeric
material of the reinforcing material including a polymeric matrix loaded with
reinforcing
particles constitutes at least part of a ground-engaging outer surface of a
carcass of the
track;
Figure 44 shows an example of a variant in which a layer of the reinforcing
polymeric
material of the reinforcing material including a polymeric matrix loaded with
reinforcing
particles constitutes at least part of an inner surface of the carcass of the
track;
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Figures 45A to 45C shows examples of variants in which the reinforcing
material of the
track comprises a layer of reinforcing polymeric material constituting at
least part of the
ground-engaging outer surface of the carcass and a layer of reinforcing
polymeric
material constituting at least part of the inner surface of the carcass;
Figure 46 shows a perspective view of an example of a variant of a traction
projection of
the track where a layer of reinforcing polymeric material of the reinforcing
material,
which includes a polymeric matrix loaded with reinforcing particles, of the
track
constitutes at least part of a rear surface of the traction projection;
Figure 47 shows a perspective view of an example of a variant of the traction
projection
of the track in which a layer of reinforcing polymeric material of the
reinforcing material,
which includes a polymeric matrix loaded with reinforcing particles, of the
track
constitutes at least part of a front surface of the traction projection;
Figure 48 shows an illustration of an example of reinforcing material which
includes a
polymeric matrix loaded with reinforcing particles;
Figure 49 shows a longitudinal cross-sectional view of an example of a variant
of the
traction projection of the track in which the reinforcing material includes a
polymeric
matrix loaded with reinforcing particles of the track and comprises a layer of
reinforcing
polymeric material constituting at least part of the periphery of the traction
projection
and a layer of reinforcing polymeric material constituting at least part of
the ground-
engaging outer surface of the carcass of the track;
Figure 50 shows a cross-sectional view of an example of a variant of the
traction
projection of the track where a layer of reinforcing polymeric material of the
reinforcing
material, which includes a polymeric matrix loaded with reinforcing particles,
of the track
constitutes at least part of a rear surface of the traction projection;
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Figure 51 shows a cross-sectional view of an example of a variant of the
traction
projection of the track where a layer of reinforcing polymeric material of the
reinforcing
material, which includes a polymeric matrix loaded with reinforcing particles,
of the track
constitutes at least part of a front surface of the traction projection;
Figure 52 shows a longitudinal cross-sectional view of an example of a variant
of a
drive/guide lug of the track in which the reinforcing material of the track
includes a
polymeric matrix loaded with reinforcing particles and constitutes at least
part of a
periphery of the drive/guide lug; and
Figure 53 shows a cross-sectional view of an example of a variant of the
traction
projection of the track where the reinforcing material, which includes a
polymeric matrix
loaded with reinforcing particles, of the track constitutes an entirety of a
traction
projection and a layer of reinforcing polymeric material of the reinforcing
material
constitutes at least part of the outer surface of the carcass.
It is to be expressly understood that the description and drawings are only
for the
purpose of illustrating certain embodiments of the invention and are an aid
for
understanding. They are not intended to be a definition of the limits of the
invention.
DETAILED DESCRIPTION OF EMBODIMENTS
Figure 1 shows an example of a vehicle 10 comprising a track system 14 in
accordance
with an embodiment of the invention. In this embodiment, the vehicle 10 is a
snowmobile. The snowmobile 10 is designed for travelling on snow and in some
cases
ice.
The snowmobile 10 comprises a frame 11, a powertrain 12, the track system 14,
a ski
system 17, a seat 18, and a user interface 20, which enables a user to ride,
steer and
CA 3012659 2018-07-26
otherwise control the snowmobile 10. The track system 14 comprises a track 21
to
engage the ground for traction of the snowmobile 10.
In various embodiments, as further discussed below, the track system 14,
including the
track 21, may have features to enhance its traction, floatation, and/or other
aspects of
its performance, including the track 21 that may comprise reinforcing material
(e.g.,
reinforcing polymeric material) that is stronger (e.g., stiffer, harder,
and/or more
resistant to wear) than elastomeric material of the track 21, such as to
improve rigidity
characteristics of the track 21, reduce noise generated by the track system
14, improve
a resistance to wear (e.g., to cutting, chipping, chunking, cracking and/or
tearing) of the
track 21, enhance heat management (e.g., improve heat dissipation or reduce
heat
build-up) within the track 21, and/or reduce a weight of the track 21.
The powertrain 12 is configured for generating motive power and transmitting
motive
power to the track system 14 to propel the snowmobile 10 on the ground. To
that end,
the powertrain 12 comprises a prime mover 15, which is a source of motive
power that
comprises one or more motors (e.g., an internal combustion engine, an electric
motor,
etc.). For example, in this embodiment, the prime mover 15 comprises an
internal
combustion engine. In other embodiments, the prime mover 15 may comprise
another
type of motor (e.g., an electric motor) or a combination of different types of
motor (e.g.,
an internal combustion engine and an electric motor). The prime mover 15 is in
a driving
relationship with the track system 14. That is, the powertrain 12 transmits
motive power
from the prime mover 15 to the track system 14 in order to drive (i.e., impart
motion to)
the track system 14.
The ski system 17 is turnable to allow steering of the snowmobile 10. In this
embodiment, the ski system 17 comprises a pair of skis 191, 192 connected to
the frame
11 via a ski-supporting assembly 13.
The seat 18 accommodates the user of the snowmobile 10. In this case, the seat
18 is a
straddle seat and the snowmobile 10 is usable by a single person such that the
seat 18
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accommodates only that person driving the snowmobile 10. In other cases, the
seat 18
may be another type of seat, and/or the snowmobile 10 may be usable by two
individuals, namely one person driving the snowmobile 10 and a passenger, such
that
the seat 18 may accommodate both of these individuals (e.g., behind one
another) or
the snowmobile 10 may comprise an additional seat for the passenger.
The user interface 20 allows the user to interact with the snowmobile 10 to
control the
snowmobile 10. More particularly, the user interface 20 comprises an
accelerator, a
brake control, and a steering device that are operated by the user to control
motion of
the snowmobile 10 on the ground. In this case, the steering device comprises
handlebars, although it may comprise a steering wheel or other type of
steering element
in other cases. The user interface 20 also comprises an instrument panel
(e.g., a
dashboard) which provides indicators (e.g., a speedometer indicator, a
tachometer
indicator, etc.) to convey information to the user.
The track system 14 is configured to engage the ground to generate traction
for the
snowmobile 10. With additional reference to Figures 2 and 3, the track system
14
comprises the track 21 and a track-engaging assembly 24 for driving and
guiding the
track 21 around the track-engaging assembly 24. More particularly, in this
embodiment,
the track-engaging assembly 24 comprises a frame 23 and a plurality of track-
contacting wheels which includes a plurality of drive wheels 221, 222 and a
plurality of
idler wheels that includes rear idler wheels 261, 262, lower roller wheels 281-
286, and
upper roller wheels 301, 302. As it is disposed between the track 21 and the
frame 11 of
the snowmobile 10, the track-engaging assembly 24 can be viewed as
implementing a
suspension for the snowmobile 10. The track system 14 has a longitudinal
direction and
a first longitudinal end and a second longitudinal end that define a length of
the track
system 14, a widthwise direction and a width that is defined by a width W of
the track
21, and a heightwise direction that is normal to its longitudinal direction
and its
widthwise direction.
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The track 21 is configured to engage the ground to provide traction to the
snowmobile
10. A length of the track 21 allows the track 21 to be mounted around the
track-
engaging assembly 24. In view of its closed configuration without ends that
allows it to
be disposed and moved around the track-engaging assembly 24, the track 21 can
be
referred to as an "endless" track. With additional reference to Figures 4 to
7, the track
21 comprises an inner side 25 for facing the track-engaging assembly 24 and a
ground-
engaging outer side 27 for engaging the ground. A top run 65 of the track 21
extends
between the longitudinal ends of the track system 14 and over the track-
engaging
assembly 24 (including over the wheels 221, 222, 261, 282, 281-286, 301, 302),
and a
bottom run 66 of the track 21 extends between the longitudinal ends of the
track system
14 and under the track-engaging assembly 24 (including under the wheels 221,
222, 281,
262, 281-286, 301, 302). The bottom run 66 of the track 21 defines an area of
contact 59
of the track 21 with the ground which generates traction and bears a majority
of a load
on the track system 14, and which will be referred to as a "contact patch" of
the track 21
with the ground. The track 21 has a longitudinal axis 85 which defines a
longitudinal
direction of the track 21 (i.e., a direction generally parallel to its
longitudinal axis) and
transversal directions of the track (i.e., directions transverse to its
longitudinal axis),
including a widthwise direction of the track (i.e., a lateral direction
generally
perpendicular to its longitudinal axis). The track 21 has a thickness
direction normal to
its longitudinal and widthwise directions.
The track 21 is elastomeric, i.e., comprises elastomeric material 53, to be
flexible
around the track-engaging assembly 24. The elastomeric material 53 of the
track 21 can
include any polymeric material with suitable elasticity. In this embodiment,
the
elastomeric material of the track 21 includes rubber. Various rubber compounds
may be
used and, in some cases, different rubber compounds may be present in
different areas
of the track 21. In other embodiments, the elastomeric material 53 of the
track 21 may
include another elastomer in addition to or instead of rubber (e.g.,
polyurethane
elastomer).
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In this embodiment, as further discussed later, as shown in Figure 8, the
track 21 also
comprises reinforcing material 51 (e.g., reinforcing polymeric material) that
is
significantly stronger (e.g., stiffer, harder, and/or more resistant to wear)
than the
elastomeric material 53. This may enhance various aspects of the track system
14,
such as, for example, by improving the rigidity characteristics of the track
21, reducing
the noise generated by the track system 14, improving a resistance to wear
(e.g., to
cutting, chipping, chunking, cracking and/or tearing) of the track 21, enhance
heat
management
(e.g., improve heat dissipation or reduce heat build-up) within the track 21,
and/or
reduce a weight of the track 21.
More particularly, the track 21 comprises an endless body 35 underlying its
inner side
25 and ground-engaging outer side 27. In view of its underlying nature, the
body 35 will
be referred to as a "carcass". The carcass 35 is elastomeric in that it
comprises
elastomeric material 38 which allows the carcass 35 to elastically change in
shape and
thus the track 21 to flex as it is in motion around the track-engaging
assembly 24. The
elastomeric material 38, which is part of the elastomeric material 53 of the
track 21, can
be any polymeric material with suitable elasticity. In this embodiment, the
elastomeric
material 38 includes rubber. Various rubber compounds may be used and, in some
cases, different rubber compounds may be present in different areas of the
carcass 35.
In other embodiments, the elastomeric material 38 may include another
elastomer in
addition to or instead of rubber (e.g., polyurethane elastonner).
In this embodiment, as shown in Figures 9A and 9B, the carcass 35 comprises a
plurality of reinforcements 451-45p embedded in its rubber 38. These
reinforcements
451-45p can take on various forms.
For example, in this embodiment, a subset of the reinforcements 451-45p is a
plurality of
transversal stiffening rods 361-36N that extend transversally to the
longitudinal direction
of the track 21 to provide transversal rigidity to the track 21. More
particularly, in this
embodiment, the transversal stiffening rods 361-36N extend in the widthwise
direction of
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the track 21. Each of the transversal stiffening rods 361-36N may have various
shapes
and be made of any suitably rigid material (e.g., metal, polymer or composite
material).
As another example, in this embodiment, the reinforcements 45, 45j are
reinforcing
layers that are flexible in the longitudinal direction of the track 21.
For instance, in this embodiment, the reinforcement 45, is a layer of
reinforcing cables
371-37m that are adjacent to one another and extend generally in the
longitudinal
direction of the track 21 to enhance strength in tension of the track 21 along
its
longitudinal direction. In this case, each of the reinforcing cables 371-37m
is a cord
including a plurality of strands (e.g., textile fibers or metallic wires). In
other cases, each
of the reinforcing cables 371-37m may be another type of cable and may be made
of any
material suitably flexible longitudinally (e.g., fibers or wires of metal,
plastic or composite
material). In some examples of implementation, respective ones of the
reinforcing
cables 371-37m may be constituted by a single continuous cable length wound
helically
around the track 21. In other examples of implementation, respective ones of
the
transversal cables 371-37m may be separate and independent from one another
(i.e.,
unconnected other than by rubber of the track 21).
Also, in this embodiment, the reinforcement 45j is a layer of reinforcing
fabric 43. The
reinforcing fabric 43 comprises thin pliable material made usually by weaving,
felting,
knitting, interlacing, or otherwise crossing natural or synthetic elongated
fabric
elements, such as fibers, filaments, strands and/or others, such that some
elongated
fabric elements extend transversally to the longitudinal direction of the
track 21 to have
a reinforcing effect in a transversal direction of the track 21. For instance,
the reinforcing
fabric 43 may comprise a ply of reinforcing woven fibers (e.g., nylon fibers
or other
synthetic fibers). For example, the reinforcing fabric 43 may protect the
transversal
stiffening rods 361-36N, improve cohesion of the track 21, and counter its
elongation.
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In some embodiments, as shown in Figure 9B, the carcass 35 may comprise only
one
type of reinforcement (e.g., the reinforcing cables 371-37m) or any other
selected
combination of the above-mentioned reinforcements 451-45p.
The carcass 35 may be molded into shape in a molding process during which the
rubber 38 is cured. For example, in this embodiment, a mold may be used to
consolidate layers of rubber providing the rubber 38 of the carcass 35, the
reinforcing
cables 371-37m and the layer of reinforcing fabric 43.
The ground-engaging outer side 27 of the track 21 comprises a ground-engaging
outer
surface 31 of the carcass 35 and a plurality of traction projections 581-58T
that project
from the ground-engaging outer surface 31 to enhance traction on the ground.
The
traction projections 581-58T, which can be referred to as "traction lugs" or
"traction
profiles", may have any suitable shape (e.g., straight shapes, curved shapes,
shapes
with straight parts and curved parts, etc.).
A height Ho of a traction projection 58, may have any suitable value. For
example, in
some embodiments, the height Ho of the traction projection 58, may be at least
2
inches, in some cases at least 4 inches, in some cases at least 6 inches, and
in some
cases even more. The height of the traction projection 58, may have any other
suitable
value in other embodiments. The traction projection 58, also has a
longitudinal axis 75
and a first longitudinal end 3081 and a second longitudinal end 3082 that
define a length
L of the traction projection 58,. The longitudinal axis 75 of the traction
projection 58,
extends transversally to the longitudinal direction of the track 21, in this
example in the
widthwise direction of the track 21.
In this embodiment, each of the traction projections 581-58T is an elastomeric
traction
projection in that it comprises elastomeric material 41. The elastomeric
material 41,
which is part of the elastomeric material 53 of the track 21, can be any
polymeric
material with suitable elasticity. More particularly, in this embodiment, the
elastomeric
material 41 includes rubber. Various rubber compounds may be used and, in some
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cases, different rubber compounds may be present in different areas of each of
the
traction projections 581-58T. In other embodiments, the elastomeric material
41 may
include another elastomer in addition to or instead of rubber (e.g.,
polyurethane
elastomer).
The traction projections 581-58T may be provided on the ground-engaging outer
side 27
in various ways. For example, in this embodiment, the traction projections 581-
58T are
provided on the ground-engaging outer side 27 by being molded with the carcass
35.
The inner side 25 of the track 21 comprises an inner surface 32 of the carcass
35 and a
plurality of inner projections 341-34D that project from the inner surface 32
and are
positioned to contact the track-engaging assembly 24 (e.g., at least some of
the wheels
221, 222, 261, 262, 281-286, 301, 302) to do at least one of driving (i.e.,
imparting motion
to) the track 21 and guiding the track 21. Since each of them is used to do at
least one
of driving the track 21 and guiding the track 21, the inner projections 341-
3413 can be
referred to as "drive/guide projections" or "drive/guide lugs". In some cases,
a
drive/guide lug 34, may interact with a given one of the drive wheels 221, 222
to drive the
track 21, in which case the drive/guide lug 34, is a drive lug. In other
cases, a
drive/guide lug 34, may interact with a given one of the idler wheels 261,
262, 281-282,
301, 302 and/or another part of the track-engaging assembly 24 to guide the
track 21 to
maintain proper track alignment and prevent de-tracking without being used to
drive the
track 21, in which case the drive/guide lug 34, is a guide lug. In yet other
cases, a
drive/guide lug 34, may both (i) interact with a given one of the drive wheels
221, 223 to
drive the track 21 and (ii) interact with a given one of the idler wheels 261,
262, 281-286,
301, 302 and/or another part of the track-engaging assembly 24 to guide the
track 21, in
which case the drive/guide lug 34, is both a drive lug and a guide lug. A
height H, of a
drive/guide lug 34), may have any suitable value.
In this embodiment, each of the drive/guide lugs 341-3413 is an elastomeric
drive/guide
lug in that it comprises elastomeric material 42. The elastomeric material 42,
which is
part of the elastomeric material 53 of the track 21, can be any polymeric
material with
17
CA 3012659 2018-07-26
suitable elasticity. More particularly, in this embodiment, the elastomeric
material 42
includes rubber. Various rubber compounds may be used and, in some cases,
different
rubber compounds may be present in different areas of each of the drive/guide
lugs 341-
34D. In other embodiments, the elastomeric material 42 may include another
elastomer
in addition to or instead of rubber (e.g., polyurethane elastomer).
The drive/guide lugs 341-34D may be provided on the inner side 25 in various
ways. For
example, in this embodiment, the drive/guide lugs 341-34D are provided on the
inner
side 25 by being molded with the carcass 35.
In this embodiment, the carcass 35 has a thickness Tc which is relatively
small. The
thickness Tc of the carcass 35 is measured from the inner surface 32 to the
ground-
engaging outer surface 31 of the carcass 35 between longitudinally-adjacent
ones of the
traction projections 581-581-. For example, in some embodiments, the thickness
Tc of the
carcass 35 may be no more than 0.25 inches, in some cases no more than 0.22
inches,
in some cases no more than 0.20 inches, and in some cases even less (e.g., no
more
than 0.18 or 0.16 inches). The thickness T, of the carcass 35 may have any
other
suitable value in other embodiments.
The track-engaging assembly 24 is configured to drive and guide the track 21
around
the track-engaging assembly 24.
Each of the drive wheels 221, 222 is rotatable by an axle for driving the
track 21. That is,
power generated by the prime mover 15 and delivered over the powertrain 12 of
the
snowmobile 10 rotates the axle, which rotates the drive wheels 221, 222, which
impart
motion of the track 21. In this embodiment, each drive wheel 22, comprises a
drive
sprocket engaging some of the drive/guide lugs 341-34D of the inner side 25 of
the track
21 in order to drive the track 21. In other embodiments, the drive wheel 22,
may be
configured in various other ways. For example, in embodiments where the track
21
comprises drive holes, the drive wheel 22, may have teeth that enter these
holes in
order to drive the track 21. As yet another example, in some embodiments, the
drive
18
CA 3012659 2018-07-26
wheel 22; may frictionally engage the inner side 25 of the track 21 in order
to frictionally
drive the track 21. The drive wheels 221, 222 may be arranged in other
configurations
and/or the track system 14 may comprise more or less drive wheels (e.g., a
single drive
wheel, more than two drive wheels, etc.) in other embodiments.
The idler wheels 261, 262, 281-286, 301, 302 are not driven by power supplied
by the
prime mover 15, but are rather used to do at least one of guiding the track 21
as it is
driven by the drive wheels 221, 222, tensioning the track 21, and supporting
part of the
weight of the snowmobile 10 on the ground via the track 21. More particularly,
in this
embodiment, the rear idler wheels 261, 262 are trailing idler wheels that
maintain the
track 21 in tension, guide the track 21 as it wraps around them, and can help
to support
part of the weight of the snowmobile 10 on the ground via the track 21. The
lower roller
wheels 281-286 roll on the inner side 25 of the track 21 along the bottom run
66 of the
track 21 to apply the bottom run 66 on the ground. The upper roller wheels
301, 302 roll
on the inner side 25 of the track 21 along the top run 65 of the track 21 to
support and
guide the top run 65 as the track 21 moves. The idler wheels 261, 262, 281-
286, 301, 302
may be arranged in other configurations and/or the track assembly 14 may
comprise
more or less idler wheels in other embodiments.
The frame 23 of the track system 14 supports various components of the track-
engaging assembly 24, including, in this embodiment, the idler wheels 261,
262, 281-286,
301, 302. More particularly, in this embodiment, the frame 23 comprises an
elongate
support 62 extending in the longitudinal direction of the track system 14
along the
bottom run 66 of the track 21 and frame members 491-49F extending upwardly
from the
elongate support 62.
The elongate support 62 comprises rails 441, 442 extending in the longitudinal
direction
of the track system 14 along the bottom run 66 of the track 21. In this
example, the idler
wheels 261, 262, 281-286 are mounted to the rails 441, 442. In this
embodiment, the
elongate support 62 comprises sliding surfaces 771, 772 for sliding on the
inner side 25
of the track 21 along the bottom run 66 of the track 21. Thus, in this
embodiment, the
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CA 3012659 2018-07-26
idler wheels 261, 262, 281-286 and the sliding surfaces 771, 772 of the
elongate support
62 can contact the bottom run 66 of the track 21 to guide the track 21 and
apply it onto
the ground for traction. In this example, the sliding surfaces 771, 772 can
slide against
the inner surface 32 of the carcass 35 and can contact respective ones of the
drive/guide lugs 341-34D to guide the track 21 in motion. Also, in this
example, the
sliding surfaces 771, 772 are curved upwardly in a front region of the track
system 14 to
guide the track 21 towards the drive wheels 221, 222. In some cases, as shown
in
Figures 5 and 6, the track 21 may comprise slide members 391-39s that slide
against
the sliding surfaces 771, 772 to reduce friction. The slide members 391-39s,
which can
sometimes be referred to as "clips", may be mounted via holes (i.e., windows)
401-40H
of the track 21. In other cases, the track 21 may be free of such slide
members.
In this embodiment, the elongate support 62 comprises sliders 331, 332 mounted
to
respective ones of the rails 441, 442 and comprising respective ones of the
sliding
surfaces 771, 772. In this embodiment, the sliders 331, 332 are mechanically
interlocked
with the rails 441, 442. In other embodiments, instead of or in addition to
being
mechanically interlocked with the rails 441, 442, the sliders 331, 332 may be
fastened to
the rails 441, 442. For example, in some embodiments, the sliders 331, 332 may
be
fastened to the rails 441, 442 by one or more mechanical fasteners (e.g.,
bolts, screws,
etc.), by an adhesive, and/or by any other suitable fastener.
In some examples, each slider 331 may comprise a low-friction material which
may
reduce friction between its sliding surface T7; and the inner side 25 of the
track 21. For
instance, the slider 33; may comprise a polymeric material having a low
coefficient of
friction with the rubber of the track 21. For example, in some embodiments,
the slider
33; may comprise a thermoplastic material (e.g., a Hifax polypropylene). The
slider 33;
may comprise any other suitable material in other embodiments. For instance,
in some
embodiments, the sliding surface 77; of the slider 33; may comprise a coating
(e.g., a
polytetrafluoroethylene (PTFE) coating) that reduces friction between it and
the inner
side 25 of the track 21, while a remainder of the slider 33; may comprise any
suitable
material (e.g., a metallic material, another polymeric material, etc.).
CA 3012659 2018-07-26
While in embodiments considered above the sliding surface 77, is part of the
slider 33,
which is separate from and mounted to each rail 44,, in other embodiments, the
sliding
surface 77; may be part of the rail 44. That is, the sliding surface T7i may
be integrally
formed (e.g., molded, cast, or machined) as part of the rail 44.
The frame members 491-49F extend upwardly from the elongate support 62 to hold
the
upper roller wheels 301, 302 such that the upper roller wheels 301, 302 roll
on the inner
side 25 of the track 21 along the top run 65 of the track 21.
The track-engaging assembly 24 may be implemented in any other suitable way in
other
embodiments.
The reinforcing material 51 of the track 21, which is significantly stronger
(e.g., stiffer,
harder, and/or more resistant to wear) than the elastomeric material 53 of the
track 21,
may be useful for various purposes. For example, in some embodiments, the
reinforcing
material 51 may improve the rigidity characteristics of the track 21, reduce
the noise
generated by the track system 14, improve the resistance to wear (e.g., to
cutting,
chipping, chunking, cracking and/or tearing) of the track 21, enhance heat
management
(e.g., improve heat dissipation or reduce heat build-up) within the track 21,
and/or
reduce a weight of the track 21.
In various embodiments, the reinforcing material 51 of the track 21 may
constitute at
least part of one or more components of the track 21, such as the carcass 35,
the
traction projections 581-58T and/or the drive/guide lugs 341-34D. For example,
in some
embodiments, the reinforcing material 51 of the track 21 may constitute at
least part of a
periphery 80 of the track 21, such as at least part of a periphery 82 of the
carcass 35, a
periphery 84 of a traction projection 58x and/or a periphery 86 of a
drive/guide lug 34x.
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CA 3012659 2018-07-26
The reinforcing material 51 of the track 21 has a continuous material
structure and is
therefore not reinforcing fabric (e.g., such as the reinforcing fabric 43) or
reinforcing
cables (e.g., such as the reinforcing cables 371-37m).
More particularly, in various embodiments, the reinforcing material 51 of the
track 21
may comprise a layer of reinforcing material 61 contiguous to (e.g.,
overlying) the
elastomeric material 53 of a given component 67 of the track 21 (e.g., the
carcass 35, a
traction projection 58x or a drive/guide lug 34x). The layer of reinforcing
material 61 may
be thin, notably significantly thinner than the elastomeric material 53 of the
given
component 67 of the track 21. For example, in some embodiments, a ratio of a
thickness Tr of the layer of reinforcing material 61 over a thickness Te of
the elastomeric
material 53 of the given component 67 of the track 21 may be no more than 0.1,
in
some cases no more than 0.075, in some cases no more than 0.05, in some cases
no
more than 0.025, in some cases no more than 0.01, and in some cases even less.
For
instance, in some embodiments, the thickness Tr of the layer of reinforcing
material 61
may be no more than 0.02 inches, in some cases no more than 0.015 inches, in
some
cases no more than 0.012 inches, in some cases no more than 0.01 inches, in
some
cases no more than 0.005 inches, and in some cases even less. The layer of
reinforcing
material 61 may thus include a sheet (e.g., a film or other thin sheet) of the
reinforcing
material 51.
The reinforcing material 51 of the track 21 may be significantly stronger than
the
elastomeric material 53 of the track 21 in various ways. For example, in some
embodiments:
- The reinforcing material 51 may be stiffer than the elastomeric material 53.
For
instance, in some embodiments, a ratio of a modulus of elasticity (i.e.,
Young's
modulus) of the reinforcing material 51 over a modulus of elasticity of the
elastomeric material 53 may be at least 10, in some cases at least 50, in some
cases at least 80, in some cases at least 100, in some cases at least 120 and
in
some cases even more. For example, in some embodiments, the modulus of
22
CA 3012659 2018-07-26
elasticity of the reinforcing material 51 may be at least 80 MPa, in some
cases at
least 200 MPa, in some cases at least 500 MPa, in some cases at least 800 MPa,
in
some cases at least 1000 MPa and in some cases even more;
- The reinforcing material 51 may be harder than the elastomeric material 53.
For
instance, in some embodiments, a ratio of a hardness (e.g., on a Shore D
scale) of
the reinforcing material 51 over a hardness of the elastomeric material 53 may
be at
least 1.2, in some cases at least 1.5, in some cases at least 2, in some cases
at
least 2.5 and in some cases even more. For example, in some embodiments, the
hardness of the reinforcing material 51 may be at least 40 Shore D, in some
cases
at least 50 Shore D, in some cases at least 60 Shore D, in some cases at least
70
Shore D, in some cases at least 80 Shore D and in some cases even more; and/or
-
The reinforcing material 51 may be more resistant to wear (e.g., abrasion)
than the
elastomeric material 53. For instance, in some embodiments, a ratio of a wear
resistance of the reinforcing material 51 over a wear resistance of the
elastomeric
material 53 may be no more than 0.95, in some cases no more than 0.8, in some
cases no more than 0.7, in some cases no more than 0.6, in some cases no more
than 0.5 and in some cases even less. The wear resistance of the reinforcing
material 51 can be taken as an abrasion resistance of the reinforcing material
51
and the wear resistance of the elastomeric material 53 can be taken as an
abrasion
resistance of the elastomeric material 53. For example, the wear resistance of
each
of the reinforcing material 51 and the elastomeric material 53, expressed as
its
abrasion resistance, may be measured under ASTM D-5963 conditions (e.g.,
sample dimensions; loading conditions; etc.). For instance, in some
embodiments,
the abrasion resistance of the reinforcing material 51 may be at least 40 mm3,
in
some cases at least 60 mm3, in some cases at least 80 mm3, in some cases at
least
100 mm3, in some cases at least 120 mm3, in some cases at least 150 mm3 and in
some cases even more.
23
CA 3012659 2018-07-26
In this embodiment, the reinforcing material 51 is reinforcing polymeric
material. For
example, in some embodiments, the reinforcing polymeric material 51 may be non-
elastomeric (i.e., not be an elastomer). In some cases, the reinforcing
polymeric
material 51 may comprise thermoplastic material. For instance, in some
embodiments,
the reinforcing polymeric material 51 may comprise ultra-high-molecular-weight
polyethylene (UHMW or UHMWPE). The reinforcing polymeric material 51 may
comprise any other suitable polymer in other embodiments, such as polyethylene
(PE)
(e.g., low-density polyethylene (LDPE) or high-density polyethylene (HDPE)),
polypropylene (PP), polytetrafluoroethylene (PTFE), a thermoplastic elastonner
(TPE)
such as thermoplastic polyurethane (TPU), polyether ether ketone (PEEK) or
other
polyaryletherketone (PAEK), polycarbonate, nylon or other polyamide, etc.
In some examples of implementation, the reinforcing polymeric material 51 may
be a
composite material. For instance, the reinforcing polymeric material 51 may be
a fiber-
matrix composite material that comprises a polymeric matrix in which fibers
are
embedded (i.e., a fiber-reinforced polymeric material). The polymeric matrix
may include
any suitable polymeric resin (e.g., a thermoplastic or thermosetting resin,
such as
epoxy, polyethylene, polypropylene, acrylic, thermoplastic polyurethane (TPU),
polyether ether ketone (PEEK) or other polyaryletherketone (PAEK),
polyethylene
terephthalate (PET), polyvinyl chloride (PVC), poly(methyl methacrylate)
(PMMA),
polycarbonate, acrylonitrile butadiene styrene (ABS), nylon, polyimide,
polysulfone,
polyamide-imide, self-reinforcing polyphenylene, polyester, vinyl ester, vinyl
ether,
polyurethane, cyanate ester, phenolic resin, etc., a hybrid thermosetting-
thermoplastic
resin, or any other suitable resin. The fibers may be made of any suitable
material (e.g.,
carbon fibers, aramid fibers (e.g., Kevlar fibers), boron fibers, silicon
carbide fibers,
etc.).
Examples of embodiments in which the reinforcing polymeric material 51 of the
track 21
may be provided in various ways will now be discussed.
1. Carcass's periphery
24
CA 3012659 2018-07-26
In some embodiments, the reinforcing polymeric material 51 of the track 21 may
constitute at least part of the periphery 82 of the carcass 35, such as at
least part of the
inner surface 32 and/or at least part of the ground-engaging outer surface 31
of the
carcass 35. This may improve rigidity characteristics of the carcass 35 and
thus those of
the track 21, reduce the noise generated by the track system 14, improve a
resistance
to wear of the carcass 35, and/or reduce a weight of the carcass 35 and thus
the weight
of the track 21.
For example, in some embodiments, as shown in Figure 10, the reinforcing
polymeric
material 51 may comprise a layer of reinforcing polymeric material 88
constituting at
least part of the ground-engaging outer surface 31 of the carcass 35.
Where the layer of reinforcing polymeric material 88 is stiffer than the
elastomeric
material 38 of the carcass 35, this may help to increase a longitudinal
rigidity of the
carcass 35, i.e., a rigidity of the carcass 35 in the longitudinal direction
of the track 21
which refers to the carcass's resistance to bending about an axis parallel to
the
widthwise direction of the track 21, and/or (2) a widthwise rigidity of the
carcass 35, i.e.,
a rigidity of the carcass 35 in the widthwise direction of the track 21 which
refers to the
carcass's resistance to bending about an axis parallel to the longitudinal
direction of the
track 21.
Increasing the widthwise rigidity of the carcass 35 may help to improve
traction and
floatation.
Increasing the longitudinal rigidity of the carcass 35 may help to reduce
noise generated
by the track system 14, such as in cases where the carcass 35 comprises the
transversal stiffening rods 361-36N by reducing a difference in rigidity
between areas
which have the transversal stiffening rods 361-36N and areas that do not have
the
transversal stiffening rods 361-36N when the roller wheels 281-286, 301, 302
pass over
these areas. In other words, the increased longitudinal rigidity of the
carcass 35 may
CA 3012659 2018-07-26
reduce deformation of the carcass 35 against impacts such as when the roller
wheels
281-286, 301, 302 roll over the carcass 35. This in turn may cause a reduction
in noise
generated by the track system 14.
For instance, in some embodiments, the track 21 may generate less noise than
if the
layer of reinforcing polymeric material 88 was omitted but the track 21 was
otherwise
identical. For instance, in some embodiments, a noise level generated by the
track 21 at
a given speed may be at least 2%, in some cases at least 4%, and in some cases
at
least 6% less than that which would be generated if the layer of reinforcing
polymeric
material 88 was omitted. More specifically, tests have been performed to
compare the
noise generated by a conventional track (i.e., a track without the layer of
polymeric
reinforcing material 88 but otherwise identical to the track 21) to the noise
generated by
two variants of the track 21 which include the layer of reinforcing polymeric
material 88.
As shown in Figure 40, test data indicates that at a vehicle speed of
approximately 27
mph and above, the noise generated by the track 21 (i.e., with the layer of
reinforcing
polymeric material 88) is less than the noise generated by the conventional
track at the
same vehicle speed. More particularly, in the vehicle speed range between 38
mph and
60 mph, the noise generated by the track 21 is over 3% less than the noise
generated
by the conventional track. For instance, the noise generated by the track 21
in this
vehicle speed range may be between 3% and 6% less than the noise generated by
the
conventional track at a similar vehicle speed range.
Where the layer of reinforcing polymeric material 88 is more resistant to wear
(e.g.,
abrasion and/or tearing) than the elastomeric material 38 of the carcass 35,
this may
help to protect the carcass 35 and reduce wear of the carcass 35 as the track
21 travels
on the ground.
This may also help to reduce the thickness T, of the carcass 35, such as by
using less
of the elastomeric material 38 of the carcass 35. In turn, this may reduce the
weight of
the carcass 35 and, thus, the weight of the track 21. For example, in some
embodiments, the thickness Tc of the carcass 35 may be no more than 0.2
inches, in
26
CA 3012659 2018-07-26
some cases no more than 0.018 inches, in some cases no more than 0.016 inches,
in
some cases no more than 0.014 inches, in some cases no more than 0.012 inches
and
in some cases even less.
In this embodiment, the layer of reinforcing polymeric material 88 occupies at
least a
substantial part of each of a plurality of traction-projection-free areas 901-
90F of the
ground-engaging outer surface 31, i.e., areas of the ground-engaging outer
surface 31
that are disposed between respective ones of the traction projections 581-58T
and that
are free of traction projections. For instance, the layer of reinforcing
polymeric material
88 may occupy at least a majority (i.e., a majority or an entirety) of the
width W of the
track 21. More specifically, in this embodiment, the layer of reinforcing
polymeric
material 88 occupies the entirety of the width W of the track 21. Moreover,
the layer of
reinforcing polymeric material 88 may occupy at least a majority (i.e., a
majority or an
entirety) of a dimension DF of a traction-projection-free area 90; in the
longitudinal
direction of the track 21. In this embodiment, the layer of reinforcing
polymeric material
88 occupies the entirety of the dimension DF.
Furthermore, in this embodiment, the layer of reinforcing polymeric material
88 is thin.
For instance, in this embodiment, a thickness T1 of the layer of reinforcing
polymeric
material 88 is less than the thickness Tc of the carcass 35. For example, in
some cases,
a ratio of the thickness T1 of the layer of reinforcing polymeric material 88
over the
thickness Te of the carcass 35 may be no more than 0.15, in some cases no more
than
0.1, in some cases no more than 0.05, and in some cases even less (e.g.,
0.02).
As another example, as shown in Figure 11, the reinforcing polymeric material
51 may
comprise a layer of reinforcing polymeric material 92 constituting at least
part of the
inner surface 32 of the carcass 35.
This may have similar effects as described above in respect of the layer of
reinforcing
polymeric material 88 constituting at least part of the ground-engaging outer
surface 31
of the carcass 35.
27
CA 3012659 2018-07-26
In this embodiment, the layer of reinforcing polymeric material 92 may occupy
at least a
majority (i.e., a majority or an entirety) of the width W of the track 21.
More specifically,
in this embodiment, the layer of reinforcing polymeric material 92 occupies
the entirety
of the width W of the track 21.
Also, in this embodiment, the layer of reinforcing polymeric material 92 may
occupy at
least a substantial part of each of a plurality of drive/guide-lug-free areas
931-93F of the
inner surface 32, i.e., areas of the inner surface 32 that are disposed
between
respective ones of the drive/guide lugs 341-34D and that are free of
drive/guide lugs. For
instance, the layer of reinforcing polymeric material 88 may occupy at least a
majority
(i.e., a majority or an entirety) of the width W of the track 21. More
specifically, in this
embodiment, the layer of reinforcing polymeric material 88 occupies the
entirety of the
width W of the track 21. Moreover, the layer of reinforcing polymeric material
88 may
occupy at least a majority (i.e., a majority or an entirety) of a dimension DG
of a
drive/guide-lug-free area 93, in the longitudinal direction of the track 21.
In this
embodiment, the layer of reinforcing polymeric material 92 occupies the
entirety of the
dimension DG.
Furthermore, in this embodiment, the layer of reinforcing polymeric material
92 is thin.
For instance, a thickness T2 of the layer of reinforcing polymeric material 92
is less than
the thickness Te of the carcass 35. For example, in some cases, a ratio of the
thickness
T2 of layer of reinforcing polymeric material 92 over the thickness Tc of the
carcass 35
may be no more than 0.15, in some cases no more than 0.1, in some cases no
more
than 0.05 and in some cases even less (e.g., 0.02).
As another example, in some embodiments, as shown in Figure 12, the layer of
reinforcing polymeric material 92 may include a plurality of segments 941-94s
that are
spaced apart from one another and constitute respective parts of the inner
surface 32 of
the carcass 35. This may be useful to rigidify, protect and/or otherwise
enhance certain
regions of the inner surface 32 of the carcass 35.
28
CA 3012659 2018-07-26
For instance, in this embodiment, the segments 941-94s of the layer of
reinforcing
polymeric material 92 may be disposed to engage the sliding surfaces 771, 772
of the
rails 441, 442 and/or the the idler wheels 261, 262, 281-286 of the track-
engaging
assembly 24 of the track system 14. This may help to facilitate relative
motion (e.g.,
reduce friction) between the bottom run 66 of the track 21 and the sliding
surfaces 771,
772 and/or the the idler wheels 261, 262, 281-286.
Where a coefficient of friction between the reinforcing polymeric material 51
and the
sliding surfaces 771, 772 and/or the the idler wheels 261, 262, 281-286 is
less than a
coefficient of friction between the elastomeric material 38 of the carcass 35
and the
sliding surfaces 771, 772 and/or the the idler wheels 261, 262, 281-286, this
may help to
reduce frictional effects between these components.
More particularly, in this embodiment, the segments 941-94, of the layer of
reinforcing
polymeric material 92 are disposed to slide against the sliding surfaces 771,
772 of the
rails 441, 442 of the track-engaging assembly 24. This allows the track 21 to
be free of
slide members (e.g., clips), such as the the slide members 391-39s discussed
above in
respect of Figures 5 and 6, which could otherwise be used to slide against the
sliding
surfaces 771, 772 to reduce friction. This freeness from slide members may
help to
reduce the weight of the track 21.
In some cases, as shown in Figure 13, the sliding surfaces 771, 772 of the
rails 441, 442
of the track-engaging assembly 24 may be made of a material 96 that slides
well
against the segments 941-94s of the inner side 25 of the track 21. For
example, in some
embodiments, the material 96 of the sliding surfaces 771, 772 of the rails
441, 442 of the
track-engaging assembly 24 may be metallic material, such as aluminum.
As another example, in some embodiments, as shown in Figure 14A, the
reinforcing
polymeric material 51 may comprise the layer of reinforcing polymeric material
92
constituting at least part of the inner surface 32 of the carcass 35 and the
layer of
29
CA 3012659 2018-07-26
reinforcing polymeric material 88 constituting at least part of the ground-
engaging outer
surface 31 of the carcass 35.
In some embodiments, the layer of reinforcing polymeric material 92
constituting at least
part of the inner surface 32 of the carcass 35 and the layer of reinforcing
polymeric
material 88 constituting at least part of the ground-engaging outer surface 31
of the
carcass 35 may be substantially identical in thickness and material
composition. That is,
the thickness T1 of the layer of reinforcing polymeric material 88 is
substantially identical
to the thickness T2 of the layer of reinforcing polymeric material 92 and a
material
composition of the layer of reinforcing polymeric material 88 is substantially
identical to
a material composition of the layer of reinforcing polymeric material 92.
In other embodiments, the layer of reinforcing polymeric material 92
constituting at least
part of the inner surface 32 of the carcass 35 and the layer of reinforcing
polymeric
material 88 constituting at least part of the ground-engaging outer surface 31
of the
carcass 35 may differ in thickness and/or material composition. That is, the
thickness Ti
of the layer of reinforcing polymeric material 88 is different from the
thickness T2 of the
layer of reinforcing polymeric material 92 and/or the material composition of
the layer of
reinforcing polymeric material 88 is different from the material composition
of the layer
of reinforcing polymeric material 92.
For instance, in some embodiments, a stiffness of the layer of reinforcing
polymeric
material 92 constituting at least part of the inner surface 32 of the carcass
35 may be
different from a stiffness of the layer of reinforcing polymeric material 88
constituting at
least part of the ground-engaging outer surface 31 of the carcass 35.
Notably, the layer of reinforcing polymeric material 88 constituting at least
part of the
ground-engaging outer surface 31 of the carcass 35 may be stiffer than the
layer of
reinforcing polymeric material 92 constituting at least part of the inner
surface 32 of the
carcass 35. This may be implemented in various ways. For example, the
thickness T1 of
the layer of reinforcing polymeric material 88 may be greater than the
thickness T2 of
CA 3012659 2018-07-26
the layer of reinforcing polymeric material 92. For instance, in some cases, a
ratio Tim
of the thickness T1 of the layer of reinforcing polymeric material 88 over the
thickness T2
of the layer of reinforcing polymeric material 92 may be at least 1.1, in some
cases at
least 1.3, in some cases at least 1.5, in some cases at least. 1.7, in some
cases at least
2 and in some cases even more.
Alternatively or additionally, a material 89 of the layer of reinforcing
polymeric material
88 constituting at least part of the ground-engaging outer surface 31 of the
carcass 35
may be stiffer than a material 91 of the layer of reinforcing polymeric
material 92
constituting at least part of the inner surface 32 of the carcass 35. For
instance, in some
cases, a ratio of the modulus of elasticity of the material 89 of the layer of
reinforcing
polymeric material 88 over the modulus of elasticity of the material 91 of the
layer of
reinforcing polymeric material 92 may be at least 2, in some cases at least 5,
in some
cases at least 10, in some cases at least 20, in some cases at least 35 and in
some
cases even more.
In other embodiments, the layer of reinforcing polymeric material 92
constituting at least
part of the inner surface 32 of the carcass 35 may be stiffer than the layer
of reinforcing
polymeric material 88 constituting at least part of the ground-engaging outer
surface 31
of the carcass 35.
For example, the thickness T2 of the layer of reinforcing polymeric material
92 may be
greater than the thickness T1 of the layer of reinforcing polymeric material
88. For
instance, in some cases, a ratio T2fr1 of the thickness T2 of the layer of
reinforcing
polymeric material 92 over the thickness T1 of the layer of reinforcing
polymeric material
88 may be at least 1.1, in some cases at least 1.3, in some cases at least
1.5, in some
cases at least. 1.7, in some cases at least 2 and in some cases even more.
Alternatively or additionally, the material 91 of the layer of reinforcing
polymeric material
92 constituting at least part of the inner surface 32 of the carcass 35 may be
stiffer than
the material 89 of the layer of reinforcing polymeric material 88 constituting
at least part
31
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of the ground-engaging outer surface 31 of the carcass 35. For instance, in
some
cases, a ratio of the modulus of elasticity of the material 91 of the layer of
reinforcing
polymeric material 92 over the modulus of elasticity of the material 89 of the
layer of
reinforcing polymeric material 88 may be at least 2, in some cases at least 5,
in some
cases at least 10, in some cases at least 20, in some cases at least 35 and in
some
cases even more.
In some embodiments, as shown in Figures 14B and 14C, as discussed above, the
layer of reinforcing polymeric material 88 may occupy at least a substantial
part of each
of respective ones of the traction-projection-free areas 901-90F of the ground-
engaging
outer surface 31 and the layer of reinforcing polymeric material 92 may occupy
at least
a substantial part of each of respective ones of the drive/guide-lug-free
areas 931-93F of
the inner surface 32. For instance, each of the layer of reinforcing polymeric
material 88
and the layer of reinforcing polymeric material 92 may occupy at least a
majority (i.e., a
majority or an entirety) of the width W of the track 21. More specifically, in
this
embodiment, each of the layer of reinforcing polymeric material 88 and the
layer of
reinforcing polymeric material 92 occupies the entirety of the width W of the
track 21.
Moreover, each of the layer of reinforcing polymeric material 88 and the layer
of
reinforcing polymeric material 92 may occupy at least a majority (i.e., a
majority or an
entirety) of each of the dimension DF of a traction-projection-free area 90;
in the
longitudinal direction of the track 21 and the dimension DG of a drive/guide-
lug-free area
93; in the longitudinal direction of the track 21. In this embodiment, the
layer of
reinforcing polymeric material 88 occupies the entirety of the dimension DF
and the layer
of reinforcing polymeric material 92 occupies the entirety of the dimension
D6. For
instance, in this embodiment, the layer of reinforcing polymeric material 88
comprises a
plurality of laterally-extending segments 951-95s (e.g., bands) that are
elongated
transversally to the longitudinal direction of the track 21 (e.g., in the
widthwise direction
of the track 21), spaced from one another in the longitudinal direction of the
track 21,
and disposed between longitudinally-adjacent ones of the traction projections
581-581-,
while the layer of reinforcing polymeric material 92 comprises a plurality of
laterally-
extending segments 971-97s (e.g., bands) that are elongated transversally to
the
32
CA 3012659 2018-07-26
longitudinal direction of the track 21 (e.g., in the widthwise direction of
the track 21),
spaced from one another in the longitudinal direction of the track 21, and
disposed
between longitudinally-successive ones of the drive/guide lugs 341-34D.
2. Traction projection's periphery
In some embodiments, as shown in Figures 15 and 16, the reinforcing polymeric
material 51 of the track 21 may constitute at least part of the periphery 84
of a traction
projection 58x of the track 21, such as at least part of a front surface 98, a
rear surface
100, lateral surfaces 1021, 1022, and/or a tip 104 of the traction projection
58. This may
improve rigidity characteristics of the traction projection 58, improve a
resistance to
wear of the traction projection 58, and/or reduce a weight of the traction
projection 58x
and thus the weight of the track 21.
For example, in this embodiment, the reinforcing polymeric material 51 may
comprise a
layer of reinforcing polymeric material 106 constituting at least part of a
given one of the
front surface 98 and the rear surface 100 of the traction projection 58, while
the other
one of the front surface 98 and the rear surface 100 of the traction
projection 58x is free
of reinforcing polymeric material. More particularly, in this embodiment, the
layer of
reinforcing polymeric material 106 constitutes at least part of the rear
surface 100 of the
traction projection 58, while the front surface 98 of the traction projection
58x is free of
reinforcing polymeric material.
Where the layer of reinforcing polymeric material 106 is stiffer than the
elastomeric
material 41 of the traction projection 58, this may help to increase a
rigidity of the
traction projection 58. Also, in this example, this may make it easier for the
traction
projection 58x to flex in a given way (e.g., forwardly) in the longitudinal
direction of the
track 21 than to flex in an opposite way (e.g., rearwardly) in the
longitudinal direction of
the track 21, thus creating an "asymmetrical" bending stiffness of the
traction projection
58.
33
CA 3012659 2018-07-26
Where the layer of reinforcing polymeric material 106 is more resistant to
wear (e.g.,
abrasion and/or tearing) than the elastomeric material 41 of the traction
projection 58x,
this may help to protect the traction projection 58x and reduce wear of the
traction
projection 58x as the track 21 travels on the ground.
This may also help to reduce a size of the traction projection 58, such as by
using less
of the elastomeric material 41 of the traction projection 58. In turn, this
may reduce the
weight of the traction projection 58x and, thus, the weight of the track 21.
In this embodiment, the layer of reinforcing polymeric material 106 may occupy
at least
a majority (i.e., a majority or an entirety) of the length L of the traction
projection 58x in
the widthwise direction of the track 21. In this embodiment, the layer of
reinforcing
polymeric material 106 occupies the entirety of the length L.
The layer of reinforcing polymeric material 106 is thin. For instance, in this
embodiment,
a thickness TA of the layer of reinforcing polymeric material 106 is less than
a dimension
WL of the traction projection 58x in the longitudinal direction of the track
21. For
example, in some cases, a ratio TA/ WL of the thickness TA of the layer of
reinforcing
polymeric material 106 over the dimension WL of the traction projection 58x in
the
longitudinal direction of the track 21 may be no more than 0.2, in some cases
no more
than 0.1, in some cases no more than 0.05, in some cases no more than 0.01 and
in
some cases even less (e.g., 0.004).
As another example, in some embodiments, as shown in Figure 17, the layer of
reinforcing polymeric material 106 includes a plurality of segments 1081-108c
that are
spaced apart from one another and constitute respective parts of the rear
surface 100 of
the traction projection 58x. This may be useful to rigidify, protect and/or
otherwise
enhance certain regions of the traction projection 58.
More particularly, in this embodiment, with additional reference to Figure 39,
the
segments 1081-108c are part of columns 1101-110c of the traction projection
58x of a
34
CA 3012659 2018-07-26
track 21' that is otherwise similar to the track 21. The columns 1101-110c
constitute
parts of the traction projection 58x that are enlarged relative to a majority
of the traction
projection 58õ in the longitudinal direction of the track 21. In this
embodiment, the
columns 1101-110c extend in a height direction of the traction projection 58x
for a
majority (i.e., a majority or an entirety) of the height Ho of the traction
projection 58.
More specifically, in this embodiment the columns 1101-1100 are ribs that
rigidify the
traction projection 58x. The presence of the segments 1081-108c on the columns
1101-
110c may further enhance the rigidifying effect that the columns 1101-110c
have on the
traction projection 58.
As another example, in some embodiments, as shown in Figures 18 to 20, the
reinforcing polymeric material 51 may comprise a layer of reinforcing
polymeric material
112 constituting at least part of the front surface 98 of the traction
projection 58, while
the rear surface 100 of the traction projection 58x is free of reinforcing
polymeric
material. This may have similar effects as described above in respect of the
layer of
reinforcing polymeric material 106 constituting at least part of the rear
surface 100 of the
traction projection 58x.
As another example, in some embodiments, as shown in Figure 21, the
reinforcing
polymeric material 51 may comprise the layer of reinforcing polymeric material
112
constituting at least part of the front surface 98 of the traction projection
58x and the
layer of reinforcing polymeric material 106 constituting at least part of the
rear surface
100 of the traction projection 58. This may have similar effects as described
above.
In some embodiments, the layer of reinforcing polymeric material 106
constituting at
least part of the rear surface 100 of the traction projection 58x and the
layer of
reinforcing polymeric material 112 constituting at least part of the front
surface 98 of the
traction projection 58x may be substantially identical in thickness and
material
composition. That is, the thickness TA of the layer of reinforcing polymeric
material 106
is substantially identical to a thickness TB of the layer of reinforcing
polymeric material
112 and a material composition of the layer of reinforcing polymeric material
106 is
CA 3012659 2018-07-26
substantially identical to a material composition of the layer of reinforcing
polymeric
material 112.
In other embodiments, the layer of reinforcing polymeric material 106
constituting at
least part of the rear surface 100 of the traction projection 58x and the
layer of
reinforcing polymeric material 112 constituting at least part of the front
surface 98 of the
traction projection 58x may differ in thickness and/or material composition.
That is, the
thickness TA of the layer of reinforcing polymeric material 106 is different
from the
thickness TB of the layer of reinforcing polymeric material 112 and/or the
material
composition of the layer of reinforcing polymeric material 106 is different
from the
material composition of the layer of reinforcing polymeric material 112.
For instance, in some embodiments, a stiffness of the layer of reinforcing
polymeric
material 106 constituting at least part of the rear surface 100 of the
traction projection
58x may be different from a stiffness of the layer of reinforcing polymeric
material 112
constituting at least part of the front surface 98 of the traction projection
58x.
Notably, the layer of reinforcing polymeric material 112 constituting at least
part of the
front surface 98 of the traction projection 58x may be stiffer than the layer
of reinforcing
polymeric material 106 constituting at least part of the rear surface 100 of
the traction
projection 58. This may be implemented in various ways. For example, the
thickness
TB of the layer of reinforcing polymeric material 112 may be greater than the
thickness
TA of the layer of reinforcing polymeric material 106. For instance, in some
cases, a
ratio TB/TA of the thickness TB of the layer of reinforcing polymeric material
112 over the
thickness TA of the layer of reinforcing polymeric material 106 may be at
least 1.2, in
some cases at least 1.5, in some cases at least 2, in some cases at least 3,
in some
cases at least 4 and in some cases even more.
Alternatively or additionally, a material 114 of the layer of reinforcing
polymeric material
112 constituting at least part of the front surface 98 of the traction
projection 58x may be
stiffer than a material 116 of the layer of reinforcing polymeric material 106
constituting
36
CA 3012659 2018-07-26
at least part of the rear surface 100 of the traction projection 58.. For
instance, in some
cases, a ratio of the modulus of elasticity of the material 114 of the layer
of reinforcing
polymeric material 112 over the modulus of elasticity of the material 116 of
the layer of
reinforcing polymeric material 106 may be at least 2, in some cases at least
5, in some
cases at least 10, in some cases at least 20, in some cases at least 35 and in
some
cases even more.
In other embodiments, the layer of reinforcing polymeric material 106
constituting at
least part of the rear surface 100 of the traction projection 58õ may be
stiffer than the
layer of reinforcing polymeric material 112 constituting at least part of the
front surface
98 of the traction projection 58.
For example, the thickness TA of the layer of reinforcing polymeric material
106 may be
greater than the thickness TB of the layer of reinforcing polymeric material
112. For
instance, in some cases, a ratio TA/TB of the thickness TA of the layer of
reinforcing
polymeric material 106 over the thickness TB of the layer of reinforcing
polymeric
material 112 may be at least 1.2, in some cases at least 1.5, in some cases at
least 2, in
some cases at least 3, in some cases at least 4 and in some cases even more.
Alternatively or additionally, the material 116 of the layer of reinforcing
polymeric
material 106 constituting at least part of the rear surface 100 of the
traction projection
58 may be stiffer than the material 114 of the layer of reinforcing polymeric
material
112 constituting at least part of the front surface 98 of the traction
projection 58x. For
instance, in some cases, a ratio of the modulus of elasticity of the material
116 of the
layer of reinforcing polymeric material 106 over the modulus of elasticity of
the material
114 of the layer of reinforcing polymeric material 112 may be at least 2, in
some cases
at least 5, in some cases at least 10, in some cases at least 20, in some
cases at least
35 and in some cases even more.
As another example, in some embodiments, as shown in Figure 22, the
reinforcing
polymeric material 51 may comprise a layer of reinforcing polymeric material
118
37
CA 3012659 2018-07-26
constituting at least part of the tip 104 of the traction projection 58x. This
may help to
protect the traction projection 58x against wear. This may also help to reduce
or avoid
markings on the ground by the elastomeric material 41 of the traction
projection 58,
(e.g., emulating a type of "non-marking" rubber).
As another example, in some embodiments, as shown in Figure 23, the
reinforcing
polymeric material 51 may comprise the layer of reinforcing polymeric material
112
constituting at least part of the front surface 98 of the traction projection
58x, the layer of
reinforcing polymeric material 106 constituting at least part the rear surface
100 of the
traction projection 58, and the layer of reinforcing polymeric material 118
constituting at
least part of the tip 104 of the traction projection 58x.
For instance, in this embodiment, as shown in Figure 24, the reinforcing
polymeric
material 51 may constitute at least a majority (e.g. less than an entirety) of
the periphery
84 of the traction projection 58. In this example, the reinforcing polymeric
material 51
constitutes an entirety of the periphery 84 of the traction projection 58,
such that the
elastomeric material 41 of the traction projection 58x is completely covered
by the
reinforcing polymeric material 51.
3. Drive/guide's lug periphery
In some embodiments, as shown in Figures 25 and 26, the reinforcing polymeric
material 51 of the track 21 may constitute at least part of the periphery 86
of a
drive/guide lug 34x of the track 21, such as at least part of a front surface
120, a rear
surface 122, lateral surfaces 1241, 1242, and/or a tip 126 of the drive/guide
lug 34x. This
may improve rigidity characteristics of the drive/guide lug 34, improve a
resistance to
wear of the drive/guide lug 34x, and/or reduce a weight of the drive/guide lug
34x and
thus the weight of the track 21. This may be effected as discussed above in
respect of
the reinforcing polymeric material 51 constituting at least part of the
periphery 84 of a
traction projection 58x of the track 21.
38
CA 3012659 2018-07-26
The track 21, including the reinforcing polymeric material 51, may be
manufactured in
any suitable way.
For example, in some embodiments, as mentioned above, the carcass 35 may be
molded into shape in the molding process during which the rubber 38 is cured,
such as
by consolidating layers of rubber providing the rubber 38 of the carcass 35 in
the mold,
while the reinforcing cables 371-37m and the layer of reinforcing fabric 43,
and the
traction projections 581-58T and the drive/guide lugs 341-34D are provided on
the
ground-engaging outer side 27 and the inner side 25 by being molded with the
carcass
35 in the mold. In some examples of implementation, the elastomeric material
41 of one
or more of the traction projections 581-58T and/or the elastomeric material 42
of one or
more of the drive/guide lugs 341-34D may be at least partly formed by the
layers of
rubber provided in the mold to also provide the rubber 38 of the carcass 35.
In other
examples of implementation, the elastomeric material 41 of one or more of the
traction
projections 581-581- and/or the elastomeric material 42 of one or more of the
drive/guide
lugs 341-34D may be at least partly provided by distinct pieces (e.g., blocks)
of
elastomeric material placed in the mold and spaced in the longitudinal
direction of the
track 21.
The reinforcing polymeric material 51 may be provided in any suitable way in
various
embodiments.
For instance, in some embodiments, as shown in Figure 27, the reinforcing
polymeric
material 51 may be bonded to a portion 69 of the elastomeric material 53 of
the track 21
before molding of the track 21. For instance, in some cases, the layer of
reinforcing
polymeric material 61 may be provided as a thin sheet bonded to a sheet of the
elastomeric material 53. The layer of reinforcing polymeric material 61 may be
provided
as a thin sheet by calendering or extrusion of the layer of reinforcing
polymeric material
61 or in any other suitable manner. The layer of reinforcing polymeric
material 61 may
be bonded to the sheet of elastomeric material 53 by applying pressure and
heat
between the layer of reinforcing polymeric material 61 and the sheet of
elastomeric
39
CA 3012659 2018-07-26
material 53. In addition or alternatively, in some cases, an adhesive may be
used at an
interface between the layer of reinforcing polymeric material 61 and the sheet
of
elastomeric material 53 in order to bond these to one another.
In some embodiments, as shown in Figure 28, the elastomeric material 53 of the
track
21 may be loaded with particles of reinforcing fabric material 1281-128p that
correspond
to the reinforcing polymeric material 51 to enhance bonding between the
elastomeric
material 53 and the reinforcing polymeric material 51. For instance, the
rubber 53 may
be loaded with the particles of reinforcing fabric material 1281-128p (e.g.,
in powder
form) during manufacturing of the rubber 53. Upon the sheet of reinforcing
polymeric
material 61 being provided on the sheet of rubber 53 (e.g., during calendering
or
otherwise), the sheet of reinforcing polymeric material 61 chemically
interacts with the
particles of reinforcing fabric material 1281-128p in the sheet of rubber 53
to enhance
their bonding.
In addition to enhancing the track 21, in some embodiments, the reinforcing
polymeric
material 51 may act as an unmolding agent (i.e., mold release agent) that
facilitates
release and removal of the track 21 from the mold upon completion of the
molding
process.
For instance, a friction coefficient between the reinforcing polymeric
material 51 and a
material of the mold in which the track 21 is molded may be lower than a
friction
coefficient between the elastomeric material 53 of the track 21 and the
material of the
mold. This may allow the molding process of the track 21 to be carried out
without or
with less of conventional mold release agent such as a silicone based release
agent
(e.g., a silicone resin) or polytetrafluoroethylene (PTFE).
The track 21, including the reinforcing material 51, may be implemented in
various other
ways in other embodiments.
CA 3012659 2018-07-26
For example, the reinforcing material 51 may be disposed elsewhere than at the
periphery 80 of the track 21 (e.g., instead of or in addition to being
disposed at the
periphery 80 of the track 21). For example, the reinforcing material 51 may be
disposed
internally within the carcass 35, a traction projection 58x or a drive/guide
lug 34x
As another example, the reinforcing material 51 may include two or more
different
constituents. For example, the reinforcing material 51 may include a plurality
of layers of
reinforcing polymeric material 1301-130L, where reinforcing polymeric
materials of these
layers are different from one another.
For instance, in one example of implementation, as shown in Figure 29, the
layers of
reinforcing polymeric material 1301-130L may be adjacent to one another (e.g.,
stacked).
Alternatively, in another example of implementation, as shown in Figure 30,
the layers
of reinforcing polymeric material 1301-130L may be spaced apart from one
another.
As another example, in some embodiments, as shown in Figures 31 and 32, the
reinforcing material 51 may constitute (i) at least part of a reinforcement
45x embedded
in the rubber 38 of the carcass 35 and (ii) at least part of a drive/guide lug
34x and/or at
least part of a traction projection 58x that are integral with one another
such that they
are a one-piece structure, i.e., (1) the reinforcement 45x and (2) the
drive/guide lug 34x
and/or the traction projection 58x are a single unitary piece. This may help
to enhance
the rigidity characteristics of the track 21.
For instance, in this embodiment, the reinforcing material 51 may constitute
at least part
of a transversal stiffening rod 36x and at least part of the drive/guide lugs
341-34D that
are integral with one another such that they are a one-piece structure. That
is, in this
example of implementation, as shown in Figure 31, the transversal stiffening
rod 36x
and selected ones of the drive/guide lugs 341-34D aligned with the transversal
stiffening
rod 36x in the longitudinal direction of the track 21 constitute a single
integral component
132 comprising the reinforcing material 51. This may be achieved, for example,
by
molding the transversal stiffening rod 36x and the selected ones of the
drive/guide lugs
41
CA 3012659 2018-07-26
341-34D together out of the reinforcing material 51 to obtain the single
integral
component 132 which comprises the transversal stiffening rod 36 and the
selected
ones of the drive/guide lugs 341-34D. The single integral component 132 may
then be
overmolded by the elastomeric material 53 to form the track 21.
While in the embodiment of Figure 31, the drive/guide lugs 341-34D are shown
as being
made entirely of the reinforcing material 51, this may not necessarily be the
case. For
instance, in some cases, the reinforcing material 51 may be provided only
along the
periphery 86 the drive/guide lugs 341-34D (e.g., as a thin sheet) such as to
cover at least
partially (or entirely) the elastomeric material 42 of the drive/guide lugs
341-34D. In order
to achieve such a configuration, the reinforcing material 51 constituting the
transversal
stiffening rod 36x and the selected ones of the drive/guide lugs 341-34D may
first be
molded over the elastomeric material 42 of the drive/guide lugs 341-34D.
In some embodiments, as shown in Figure 32, the reinforcing material 51 may
constitute at least part of a transversal stiffening rod 36 and at least part
of the traction
projections 581-58T that are integral with one another such that they are a
one-piece
structure. That is, the transversal stiffening rod 36 and selected ones of the
traction
projections 581-581- aligned with the transversal stiffening rod 36 in the
longitudinal
direction of the track 21 constitute a single integral component 134
comprising the
reinforcing material 51. This may be achieved, for example, by molding the
transversal
stiffening rod 36 and the selected ones of the traction projections 581-58T
together out
of the reinforcing material 51 to obtain the single integral component 134
which
comprises the transversal stiffening rod 36 and the selected ones of the
traction
projections 581-581-. The single integral component 134 may then be overmolded
by the
elastomeric material 53 to form the track 21.
While in the embodiment of Figure 32, the traction projections 581-58T are
shown as
being made entirely of the reinforcing material 51, this may not necessarily
be the case.
For instance, in some cases, the reinforcing material 51 may be provided only
along the
periphery 84 the traction projections 581-58T (e.g., as a thin sheet) such as
to cover at
42
CA 3012659 2018-07-26
least partially (or entirely) the elastomeric material 41 of the traction
projections 581-581-.
In order to achieve such a configuration, the reinforcing material 51
constituting the
transversal stiffening rod 36x and the selected ones of the traction
projections 581-58T
may first be molded over the elastomeric material 41 of the traction
projections 581-581-.
In some variants, the reinforcing material 51 may be used similarly as
discussed above
with respect to previously-presented embodiments, but may be implemented
differently.
For instance, in some variants, the reinforcing material 51 may be at least
partly
elastomeric (i.e., part or all of the reinforcing material 51 may be
elastomeric). For
example, in some embodiments, the reinforcing material 51 may be at least
predominantly (i.e., predominantly or entirely) elastomeric. In some cases,
the
reinforcing material 51 may include an elastomeric substance, alone or in
combination
with one or more other materials such as one or more performance additives.
For instance, in some embodiments, this may help to have improved heat
dissipation
and/or reduced heat build-up, improved resistance to abrasion, cutting,
chipping,
chunking and/or tearing, .
As an example, in some embodiments, in variants shown in Figures 41 to 51, the
reinforcing material 51, which is denoted 51', is an elastomeric material that
is different
from the elastomeric material 53 of the track 21 and includes an elastomeric
matrix 71
and reinforcing particles 631-63p embedded in the elastomeric matrix 71. The
reinforcing elastomeric material 51' may overly the elastomeric material 53
and
constitute at least part of the periphery 80 of the track 21, such as at least
part of the
periphery 82 of the carcass 35, the periphery 84 of a traction projection 58x
and/or the
periphery 86 of a drive/guide lug 34, as discussed above.
This may have certain similarities to the embodiment shown in Figure 28 where
the
elastomeric material 53 of the track 21 is loaded with the particles of
reinforcing fabric
material 1281-128p, except that, in this embodiment, the elastomeric material
53 of the
track 21 is free of (i.e., substantially does not contain) reinforcing
particles. That is, the
43
CA 3012659 2018-07-26
elastomeric material 53 of the track 21 is purely elastomeric without
reinforcing
particles, while the reinforcing elastomeric material 51', including its
reinforcing particles
631-63p, overlies the elastomeric material 53. Thus, in this embodiment, the
reinforcing
elastomeric material 51', including its reinforcing particles 631-63p,
constitutes a much
smaller portion of the track 21 than the elastomeric material 53, which has no
reinforcing particles and forms a bulk of the track 21. This may help to
benefit from
desired effects of the reinforcing particles 631-63p while managing the weight
of the
track 21.
More particularly, in this variant, the elastomeric matrix 71 of the
reinforcing material 51'
includes rubber 38. Various rubber compounds may be used and, in some cases,
different rubber compounds may be present in the elastomeric matrix 71. For
instance,
the elastomeric matrix 71 may include a mixture of different rubber compounds
in an
uncured state, or a plurality of pre-cured layers or parts (e.g. pre-cured
calendered
layers or parts) of rubber compounds differing (or identical) in their
composition such as
to form the elastomeric matrix 71 of the reinforcing material 51' once cured.
In other
variants, the elastomeric matrix 71 may include another elastonner in addition
to or
instead of rubber 38 (e.g., polyurethane elastomer).
The reinforcing particles 631-63p enhance overall properties of the
reinforcing material
51' compared to the elastomeric matrix 71 alone, and in turn to one or more
components of the track 21 that are at least partly constituted of the
reinforcing material
51'. For instance, in some cases, this may help to improve heat dissipation,
reduce heat
build-up, improve a resistance to abrasion, cutting, chipping, chunking and/or
tearing of
the one or more components of the track 21, such as the carcass 35, the
traction
projections 581-581- and/or the drive/guide lugs 341-34D which may be
constituted at
least in part of the reinforcing material 51'.
In this variant, the reinforcing particles 631-63p are polymeric reinforcing
particles 631-
63p. More particularly, in this variant, the polymeric reinforcing particles
631-63p
comprise ultra-high-molecular-weight polyethylene (UHMW or UHMWPE). The
44
CA 3012659 2018-07-26
polymeric reinforcing particles 631-63p may comprise any other suitable
polymer in
other cases, such as polyethylene (PE) (e.g., low-density polyethylene (LDPE)
or high-
density polyethylene (HDPE)), polypropylene (PP), polytetrafluoroethylene
(PTFE), a
thermoplastic elastomer (TPE) such as thermoplastic polyurethane (TPU),
polyether
ether ketone (PEEK) or other polyaryletherketone (PAEK), polycarbonate, nylon
or
other polyannide, etc.
In other cases, the reinforcing particles 631-63p may include any other
suitable
performance additives instead of or in addition to the above materials. For
instance, in
other cases, the reinforcing particles 631-63p may comprise fibers (e.g.,
carbon fibers,
aramid fibers (e.g., Kevlar fibers), boron fibers, silicon carbide fibers,
etc.).
Some characteristics of the reinforcing particles 631-63p other than or in
addition to their
material may affect properties of the reinforcing material 51', and in turn
the
characteristics of the one or more components of the track 21 that are at
least partly
constituted of the reinforcing material 51', as discussed below.
The reinforcing particles 631-63p may be relatively fine and/or compact. For
instance, in
this variant, the reinforcing particles 631-63p are provided as powder when
combined
with the elastomeric matrix 71.
For example, in some embodiments, the reinforcing particles 631-63p may be non-
elongated (e.g., may be spherical-like). For example, in some embodiments, an
average
sphericity of the reinforcing particles 631-63p may be at least 0.5, in some
cases at least
0.7, in some cases at least 0.9, and in some cases even higher (e.g., close to
or equal
to 1, in which case the reinforcing particles 631-63p may be generally
spherical
particles). Sphericity of a reinforcing particle 63x may be calculated as a
ratio of a
surface area of a sphere, which has a volume corresponding to that of the
reinforcing
particle 63, to a surface area of the reinforcing particle 63. Thus, in such
embodiments, the reinforcing particles 631-63p may not be elongated fibers.
CA 3012659 2018-07-26
In some embodiments, an average aspect ratio of the reinforcing particles 631-
63p,
which refers to an average ratio of a maximal dimension of each reinforcing
particle 63x
over a minimal dimension of the reinforcing particle 63x, may be no more than
8, in
some cases no more than 6, in some cases no more than 4, in some cases no more
than 2, and in some cases even less.
Also, in some embodiments, an average diameter Dx of the reinforcing particles
631-63p
may be no more than 200 m, in some cases no more than 100 p.m, in some cases
no
more than 50 pm, in some cases no more than 25 p.m, and in some cases even
less.
For instance, in some embodiments, the average diameter Dx of the reinforcing
particles
631-63p may range between 100 iim and 200 firn, in some cases between 60 iim
and
100 pm , in some cases between 30 pm and 60, and in some cases between 10 lim
and 30 p.m.
Fineness and/or compactness of the reinforcing particles 631-63p may provide
greater
adherence of the reinforcing particles 631-63p within the elastomeric matrix
71 and/or
impart isotropic properties to the reinforcing material 51' composed
therewith, as
opposed to elongated fibers, which may tend to align (e.g., in a calendering
or extruding
direction) during manufacturing, thereby imparting anisotropic properties.
There may be any suitable quantity of the reinforcing particles 631-63p in a
given
volume of the reinforcing material 51'. This may impact the properties of the
reinforcing
material 51', and in turn affect the performance of the track 21. For
instance, in some
cases where the elastomeric matrix 71 of the reinforcing material 51' includes
rubber, a
concentration C of the reinforcing particles 631-63p may be measured in parts
per
hundred rubber (PHR) and may range between 1 and 10 PHR. More particularly, in
some cases, the concentration C of the reinforcing particles 631-63p in the
reinforcing
material 51' may be at least 1 PHR, in some cases at least 5 PHR, in some
cases at
least 8 PHR, and in some cases even more, and/or no more than 10 PHR, in some
cases no more than 5 PHR, and in some cases no more than 1 PHR.
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CA 3012659 2018-07-26
As discussed above, the reinforcing material 51' may constitute at least part
of one or
more components of the track 21, such as the carcass 35, the traction
projections 581-
58T and/or the drive/guide lugs 341-34D. For example, the reinforcing material
51' of the
track 21 may constitute at least part of the periphery 80 of the track 21,
such as at least
part of the periphery 82 of the carcass 35, the periphery 84 of a traction
projection 58,
and/or the periphery 86 of a drive/guide lug 34, as discussed above with
respect to
some embodiments. That is, the reinforcing material 51' of the track 21 may
define at
least part of the ground engaging outer side 27 of the track, at least part of
the inner
side 25 of the track 21, or at least part of both the ground engaging outer
side 27 and
the inner side 25 of the track 21.
The reinforcing material 51' may be provided on at least part of the ground-
engaging
outer side 27 and/or at least part of the inner side 25 of the track 21 in
various ways. For
example, in this variant, the reinforcing material 51' is molded with the
carcass 35, the
traction projections 581-58T and/or the drive/guide lugs 341-34o of the track
21. More
particularly, in this variant, the reinforcing material 51' constitutes at
least a majority
(i.e., a majority or an entirety) of the ground-engaging outer surface 31 of
the carcass
35 and at least a majority of the periphery 84 of each of the traction
projections 581-58T.
This may improve a resistance to abrasion, cutting, chipping, chunking and/or
tearing of
the ground-engaging outer side 27 of the track 21, which may be imparted by
repetitive
ground contacts during use of the track 21. This may also improve heat
dissipation or
reduce heat build-up within the track 21, as the reinforcing material 51' may
work as a
heat barrier or heat diffuser during use, and thus this may also improve
indirectly a
durability of the track 21.
For example, in some embodiments, as shown in Figure 43, the reinforcing
material 51'
may comprise a layer of reinforcing material 76 constituting at least part of
the ground-
engaging outer surface 31 of the carcass 35, as discussed above in relation to
the layer
of reinforcing material 88. The layer of reinforcing material 76 may be a
continuous layer
or it may include a plurality of segments that are spaced apart from one
another and
constitute respective areas of the track 21 including the reinforcing material
51'.
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CA 3012659 2018-07-26
The layer of reinforcing material 76 may be thin, notably significantly
thinner than the
elastomeric material 53 of a given component 67 of the track 21 (e.g., the
carcass 35, a
traction projection 58x or a drive/guide lug 34x). For example, in some cases,
a ratio of a
thickness Tx of the layer of reinforcing material 76 over a thickness Te of
the elastomeric
material 53 of the given component 67 of the track 21 may be no more than 0.3,
in
some cases no more than 0.2, in some cases no more than 0.1, in some cases no
more
than 0.05, in some cases no more than 0.01, and in some cases an even smaller
ratio.
For example, in some cases, the thickness Tx of the layer of reinforcing
material 76 may
be no more than 1 inch, in some cases no more than 0.5 inch, in some cases no
more
than 0.25 inch, in some cases no more than 0.1 inch, in some cases no more
than 0.05
inch, in some cases no more than 0.025 inch, and in some cases even less.
The layer of reinforcing material 76 may also vary in thickness, depending on
respective
areas of the track 21 including the reinforcing material 51'. This may help to
enhance
the durability of the track 21, more particularly in areas of the track 21
that usually wear
quicker than the remainder of the track 21, such as the traction projections
58-58--
and/or the traction-projection-free areas 901-90F due to repetitive ground
contacts. For
instance, in this variant, a thickness Tx1 of the layer of reinforcing
material 76
constituting at least part of (in this case an entirety of) the periphery 84
of a traction
projection 58x is greater than a thickness Tx2 of the layer of reinforcing
material 76
constituting at least part of (in this case an entirety of) the periphery 82
of the carcass
35 at a traction-projection-free area. For example, in some cases, a ratio of
the
thickness Tx1 of the layer of reinforcing material 76 constituting at least
part of the
periphery 84 of a traction projection 58x over the thickness Tx2 of the layer
of reinforcing
material 76 constituting at least part of the periphery 82 of the carcass 35
at the traction-
projection-free area may be at least 1.1, in some cases at least 1.5, in some
cases at
least 2, in some cases at least 5, and in some cases an even greater
ratio.Also, in other
cases, the thickness Tx1 of the layer of reinforcing material 76 constituting
at least part
of the periphery 84 of a traction projection 58x is smaller than the thickness
Tx2 of the
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CA 3012659 2018-07-26
layer of reinforcing material 76 constituting at least part of the periphery
82 of the
carcass 35 at a traction-projection-free area.
The concentration C of the reinforcing particles 631-63p may also vary in the
layer of
reinforcing material 76, depending on respective areas of the track 21
including the
reinforcing material 51', in addition to or instead of a variation in
thickness of the layer of
reinforcing material 76. For instance, in some cases, the concentration C1 of
the
reinforcing particles 631-63p of the reinforcing material 51' constituting at
least part of
the periphery 84 of a traction projection 58, may be greater than the
concentration C2 of
the reinforcing particles 631-63p in the reinforcing material 51 constituting
at least part of
the periphery 82 of the carcass 35 in a traction-projection-free area. For
instance, in
some cases, a ratio of the concentration C1 over the concentration C2 is at
least 1.1, in
some cases at least 1.2, in some cases at least 1.5, in some cases at least
2.0, and in
some cases even more. In other cases, the concentration of C1 of the
reinforcing
particles 631-63p in the reinforcing material 51' constituting at least part
of the periphery
84 of a traction projection 58, may be smaller than the concentration C2 of
the
reinforcing particles 631-63p in the reinforcing material 51' constituting at
least part of
the periphery 82 of the carcass 35 at a traction-projection-free area.
The concentration of reinforcing particles 631-63p may also vary in a
thickness direction
of the layer of reinforcing material 76, such that higher or lower
concentrations of
reinforcing particles 631-63p may be voluntarily obtained in selected parts of
the track
including the reinforcing material 51'. This may be implemented for instance
when the
layer of reinforcing material 76 includes a plurality of sub-layers of
reinforcing material
51' stacked on one another. For instance, in some cases, the concentration C
of
reinforcing particles 631-63p within the layer of reinforcing material 76
decreases in the
layer of reinforcing material 76 in a given direction (i.e. the concentration
of reinforcing
particles 76 may be higher in an outer region of the layer of reinforcing
material 76 than
at an inner region of the layer of reinforcing material 76). This may provide
a
progressive change in the material properties of the reinforcing layer 51' and
thus less
stress concentrations at the junction between the reinforcing material 51' and
the
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CA 3012659 2018-07-26
elastomeric material 53 underlying the reinforcing material 51'. The
concentration of
reinforcing particles 631-63p may vary differently in other cases.
In some embodiments, as shown in Figure 44, the reinforcing polymeric material
51
may comprise a layer of reinforcing polymeric material 78 constituting at
least part of the
inner surface 32 of the carcass 35, as discussed above in relation to the
layer of
reinforcing polymeric material 92.
The reinforcing material 51' including the elastomeric matrix 71 loaded with
the
reinforcing particles 631-63p may be significantly stronger than the
elastomeric material
53 of the track 21 in various ways, and thus the presence of such reinforcing
material
51' may help the track 21 to better perform when compared to a similar track
free of
such reinforcing material 51'. Notably, in some cases:
- the reinforcing material 51' including the elastomeric matrix 71 loaded with
the
reinforcing particles 631-63p may be stiffer than the elastomeric material 53.
For
example, in some cases, a ratio of modulus of elasticity (i.e., Young's
modulus) of
such reinforcing material 51' over a modulus of elasticity of the elastomeric
material
53 is at least 2, in some cases at least 5, in some cases at least 10, in some
cases
at least 20, in some cases at least 40 and in some cases even more. For
instance,
in some cases, the modulus of elasticity of such reinforcing material 51' is
at least
1.5 MPa, in some cases at least 4 MPa, in some cases at least 6 MPa, in some
cases at least 8 MPa, in some cases at least 10 MPa and in some cases even
more;
- the reinforcing material 51' including the elastomeric matrix 71 loaded with
the
reinforcing particles 631-63p may be harder than the elastomeric material 53.
For
instance, in some cases, a ratio of a hardness on a Shore A hardness scale of
such
reinforcing material 51' over a hardness of the elastomeric material 53 is at
least
1.2, in some cases at least 1.5, in some cases at least 2, in some cases at
least 2.5
and in some cases even more. For instance, in some cases, the hardness on the
CA 3012659 2018-07-26
Shore A hardness scale of such reinforcing material 51' is at least 50, in
some
cases at least 60, in some cases at least 70, in some cases at least 80, in
some
cases at least 90 and in some cases even more; and/or
- the reinforcing material 51' including the elastomeric matrix 71 loaded with
the
reinforcing particles 631-63p may be more resistant to abrasion than the
elastomeric
material 53. For instance, in some cases, a ratio of a wear resistance of such
reinforcing material 51' over a wear resistance of the elastomeric material 53
is no
more than 0.95, in some cases no more than 0.8, in some cases no more than
0.7,
in some cases no more than 0.6, in some cases no more than 0.5 and in some
cases even less. The wear resistance of such reinforcing material 51' can be
taken
as an abrasion resistance of such reinforcing material 51' and the wear
resistance
of the elastomeric material 53 can be taken as an abrasion resistance of the
elastomeric material 53. For instance, the wear resistance of such reinforcing
material 51' and of the elastomeric material 53, expressed as its abrasion
resistance, may be measured under ASTM D-5963 conditions (e.g., sample
dimensions; loading conditions; etc.). For instance, in some embodiments, the
abrasion resistance of such reinforcing material 51' is at least 40 mm3, in
some
cases at least 60 mm3, in some cases at least 80 mm3, in some cases at least
100
mm3, in some cases at least 120 mm3, in some cases at least 150 mm3 and in
some
cases even more.
Where the layer of reinforcing polymeric material 76 of the reinforcing
material 51'
including the elastomeric matrix 71 loaded with the reinforcing particles 631-
63p is stiffer
than the elastomeric material 53 of the carcass 35, as discussed above, this
may help
to increase a longitudinal rigidity of the carcass 35, i.e., a rigidity of the
carcass 35 in the
longitudinal direction of the track 21 which refers to the carcass's
resistance to bending
about an axis parallel to the widthwise direction of the track 21, and/or (2)
a widthwise
rigidity of the carcass 35, i.e., a rigidity of the carcass 35 in the
widthwise direction of
the track 21 which refers to the carcass's resistance to bending about an axis
parallel to
the longitudinal direction of the track 21.
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CA 3012659 2018-07-26
Increasing the widthwise rigidity of the carcass 35 may help to improve
traction and
floatation.
Increasing the longitudinal rigidity of the carcass 35 may help to reduce
noise generated
by the track system 14, such as in cases where the reinforcing material 51'
including the
elastomeric matrix 71 loaded with the reinforcing particles 631-63p defines at
least part
of the ground engaging outer side 27 of the track, at least part of the inner
side 25 of the
track 21, or at least part of both the ground engaging outer side 27 and the
inner side 25
of the track 21. In other words, the increased longitudinal rigidity of the
carcass 35 may
reduce deformation of the carcass 35 against impacts such as when the roller
wheels
281-286, 301, 302 roll over the carcass 35. This in turn may cause a reduction
in noise
generated by the track system 14.
For instance, in some variants where the reinforcing material 51' including
the
elastomeric matrix 71 loaded with the reinforcing particles 631-63p defines at
least part
of the ground engaging outer side 27 of the track, at least part of the inner
side 25 of the
track 21, or at least part of both the ground engaging outer side 27 and the
inner side 25
of the track 21, the track 21 may generate less noise than if the reinforcing
polymeric
material 51' was omitted but the track 21 was otherwise identical. For
instance, in some
embodiments, a noise level generated by the track 21 at a given speed may be
at least
2%, in some cases at least 4%, and in some cases at least 6% less than that
which
would be generated if the layer of reinforcing polymeric material 88 was
omitted.
In some embodiments, as shown in Figures 45B and 45C, as discussed above, the
layer of reinforcing polymeric material 76 may occupy at least a substantial
part of each
of respective ones of the traction-projection-free areas 901-90F of the ground-
engaging
outer surface 31 and the layer of reinforcing polymeric material 78 may occupy
at least
a substantial part of each of respective ones of the drive/guide-lug-free
areas 931-93F of
the inner surface 32. For instance, each of the layer of reinforcing polymeric
material 76
and the layer of reinforcing polymeric material 78 may occupy at least a
majority (i.e., a
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CA 3012659 2018-07-26
majority or an entirety) of the width W of the track 21. More specifically, in
this
embodiment, each of the layer of reinforcing polymeric material 76 and the
layer of
reinforcing polymeric material 78 occupies the entirety of the width W of the
track 21.
Moreover, each of the layer of reinforcing polymeric material 76 and the layer
of
reinforcing polymeric material 78 may occupy at least a majority (i.e., a
majority or an
entirety) of each of the dimension DF of a traction-projection-free area 90,
in the
longitudinal direction of the track 21 and the dimension DG of a drive/guide-
lug-free area
93, in the longitudinal direction of the track 21. In this embodiment, the
layer of
reinforcing polymeric material 76 occupies the entirety of the dimension DF
and the layer
of reinforcing polymeric material 78 occupies the entirety of the dimension
D6. For
instance, in this embodiment, the layer of reinforcing polymeric material 76
comprises a
plurality of laterally-extending segments 991-99s (e.g., bands) that are
elongated
transversally to the longitudinal direction of the track 21 (e.g., in the
widthwise direction
of the track 21), spaced from one another in the longitudinal direction of the
track 21,
and disposed between longitudinally-adjacent ones of the traction projections
581-58-r,
while the layer of reinforcing polymeric material 78 comprises a plurality of
laterally-
extending segments 831-83s that are elongated transversally to the
longitudinal
direction of the track 21 (e.g., in the widthwise direction of the track 21),
spaced from
one another in the longitudinal direction of the track 21, and disposed
between
longitudinally-successive ones of the drive/guide lugs 341-34D.
In other cases, the reinforcing material 51' may constitute more of a given
component
67 of the track 21. For instance, in some embodiments, the reinforcing
material 51' may
constitute at least a majority (i.e., a majority or an entirety) of a given
component 67 of
the track 21 instead of the elastomeric material 53. For instance, instead of
being
provided as a layer of reinforcing material 76, the reinforcing material 51'
may be
provided as an extruded piece (e.g., bar) of reinforcing material 51', whereby
the
extruded piece of reinforcing material 51' may be used for forming a given
component
67 (e.g. forming a substantial portion of a traction projection 58õ or a
drive/guide lug
34x). In cases where the reinforcing material 51' constitutes a majority (e.g.
a majority or
an entirety) of a given component 67 of the track 21 such as a traction
projections 58,
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CA 3012659 2018-07-26
as discussed above, the thickness Tx2 of the layer of reinforcing material 76
constituting
at least part of the periphery 82 of the carcass 35 at a traction-projection-
free area may
take the same values as discussed above with respect to previously-presented
cases.
For instance, in some cases, the reinforcing material 51' may constitute at
least a bulk
(e.g., a majority or an entirety) of a traction projection 58õ or drive/guide
lug 34, and a
layer of reinforcing material 76 forming at least part of the inner surface 32
or the outer
surface 31 of the carcass. For instance, in the embodiment shown in Figure 53,
the
reinforcing material 51' constitutes an entirety of a traction projection 58x
and a layer of
reinforcing material 76 forms at least part of the outer surface 31 of the
carcass.
In some embodiments, the reinforcing material 51' including the elastomeric
matrix 71
and the reinforcing particles 631-63p may constitute another part of the track
21, in
addition to or instead of at least part of the periphery 80 of the track 21,
and may be
configured as described above, including for the concentration of the
reinforcing
particles 631-63p, the size and shape of the reinforcing particles, etc. For
example, in
some embodiments, the reinforcing material 51' may constitute an internal part
of the
track 21 that underlies the periphery 80 of the track 21, which may be made of
elastomeric material (e.g., without any reinforcing particles) or a layer of
the reinforcing
material 51 previously discussed in other embodiments.
While in embodiments considered above the track system 14 is part of the
snowmobile
10, a track system constructed according to principles discussed herein may be
used as
part of other off-road vehicles in other embodiments.
For example, in some embodiments, a track system constructed according to
principles
discussed herein may be used as part of an all-terrain vehicle (ATV).
Figures 33 to 36 show an ATV 210 comprising a set of track systems 2141-2144
providing traction to the ATV on the ground. The ATV 210 comprises a prime
mover 212
in a driving relationship with the track systems 2141-2144 via the ATV's
powertrain, a
seat 218, and a user interface 220, which enable a user of the ATV 210 to ride
the ATV
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CA 3012659 2018-07-26
210 on the ground. In this case, the seat 218 is a straddle seat and the ATV
210 is
usable by a single person such that the seat 218 accommodates only that person
driving the ATV 210. In other cases, the seat 218 may be another type of seat,
and/or
the ATV 210 may be usable by two individuals, namely one person driving the
ATV 210
and a passenger, such that the seat 218 may accommodate both of these
individuals
(e.g., behind one another or side-by-side) or the ATV 210 may comprise an
additional
seat for the passenger. For example, in other embodiments, the ATV 210 may be
a
side-by-side ATV, sometimes referred to as a "utility terrain vehicle" or
"UTV". The user
interface 220 comprises a steering device operated by the user to control
motion of the
ATV 210 on the ground. In this case, the steering device comprises handlebars.
In other
cases, the steering device may comprise a steering wheel or other type of
steering
element. Each of the front track systems 2141, 2142 is pivotable about a
steering axis of
the ATV 210 in response to input of the user at the handlebars in order to
steer the AN
210 on the ground.
In this embodiment, each track system 214, is mounted in place of a ground-
engaging
wheel 213, that may otherwise be mounted to the ATV 210 to propel the AN 210
on the
ground. That is, the AN 210 may be propelled on the ground by four ground-
engaging
wheels 2131-2134 with tires instead of the track systems 2141-2144. Basically,
in this
embodiment, the track systems 2141-2144 may be used to convert the AN 210 from
a
wheeled vehicle into a tracked vehicle, thereby enhancing its traction and
floatation on
the ground.
Any feature described herein with respect to the track system 14 of the
snowmobile 10,
including its track 21, may be applied to a track system 214, of the AN 210,
including
its track 221.
The snowmobile 10 and the AN 210 considered above are examples of tracked
recreational vehicles. While they can be used for recreational purposes, such
tracked
recreational vehicles may also be used for utility purposes in some cases.
CA 3012659 2018-07-26
As another example, in some embodiments, a track system constructed according
to
principles discussed herein may be used as part of a snow bike. Figure 37
shows a
snow bike 310 comprising a frame 311, a powertrain 312, a ski system 317, a
track
system 314, a seat 318, and a user interface 320 which enables a user to ride,
steer
and otherwise control the snow bike 310.
In this embodiment, as shown in Figure 38, the snow bike 310 is a motorcycle
equipped
with the ski system 317 mounted in place of a front wheel 302 of the
motorcycle 310
and the track system 314 mounted in place of a rear wheel 304 of the
motorcycle 310.
In this example, the track system 314 also replaces a rear suspension unit
(e.g., a
shock absorber and a swing arm) of the motorcycle. Basically, in this
embodiment, the
ski system 317 and the track system 314 are part of a conversion system 313
that
converts the motorcycle into a skied and tracked vehicle for travelling on
snow.
The powertrain 312 is configured for generating motive power and transmitting
motive
power to the track system 314 to propel the snow bike 310 on the ground. To
that end,
the powertrain 312 comprises a prime mover 315, which is a source of motive
power
that comprises one or more motors (e.g., an internal combustion engine, an
electric
motor, etc.). For example, in this embodiment, the prime mover 315 comprises
an
internal combustion engine. In other embodiments, the prime mover 315 may
comprise
another type of motor (e.g., an electric motor) or a combination of different
types of
motor (e.g., an internal combustion engine and an electric motor). The prime
mover 315
is in a driving relationship with the track system 314. That is, the
powertrain 312
transmits motive power from the prime mover 315 to the track system 314 in
order to
drive (i.e., impart motion to) the track system 314.
The seat 318 accommodates the user of the snow bike 310. In this case, the
seat 318 is
a straddle seat and the snow bike 310 is usable by a single person such that
the seat
318 accommodates only that person driving the snow bike 310. In other cases,
the seat
318 may be another type of seat, and/or the snow bike 310 may be usable by two
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CA 3012659 2018-07-26
individuals, namely one person driving the snow bike 310 and a passenger, such
that
the seat 318 may accommodate both of these individuals (e.g., behind one
another).
The user interface 320 allows the user to interact with the snow bike 310 to
control the
snow bike 310. More particularly, in this embodiment, the user interface 320
comprises
an accelerator, a brake control, and a steering device comprising handlebars
322 that
are operated by the user to control motion of the snow bike 510 on the ground.
The user
interface 320 also comprises an instrument panel (e.g., a dashboard) which
provides
indicators (e.g., a speedometer indicator, a tachometer indicator, etc.) to
convey
information to the user.
The ski system 317 is disposed in a front 324 of the snow bike 310 to engage
the
ground and is turnable to steer the snow bike 310. To that end, the ski system
14 is
turnable about a steering axis of the snow bike 310. The ski system 317
comprises a ski
328 to slide on the snow and a ski mount 330 that connects the ski 328 to a
front
steerable member 332 of the snow bike 310. In this embodiment where the snow
bike
310 is a motorcycle and the ski system 317 replaces the front wheel 302 of the
motorcycle, the front steerable member 332 comprises a front fork 334 of the
snow bike
310 that would otherwise carry the front wheel 302.
The ski 328 is a sole ski of the snow bike 310. That is, the snow bike 310 has
no other
ski. Notably, the ski 328 is disposed in a center of the snow bike 310 in a
widthwise
direction of the snow bike 310. In this embodiment in which the snow bike 310
is a
motocycle and the ski system 317 replaces the front wheel 302 of the
motorcycle, the
ski 328 contacts the ground where the front wheel 302 would contact the
ground.
Any feature described herein with respect to the track system 14 of the
snowmobile 10,
including its track 21, may be applied to the track system 314 of the snow
bike 310,
including its track 321.
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CA 3012659 2018-07-26
In other embodiments, a track system constructed according to principles
discussed
herein may be used as part of an agricultural vehicle (e.g., a tractor, a
harvester, etc.),
as part of a construction vehicle, forestry vehicle or other industrial
vehicle, or as part of
a military vehicle.
Certain additional elements that may be needed for operation of some
embodiments
have not been described or illustrated as they are assumed to be within the
purview of
those of ordinary skill in the art. Moreover, certain embodiments may be free
of, may
lack and/or may function without any element that is not specifically
disclosed herein.
Any feature of any embodiment discussed herein may be combined with any
feature of
any other embodiment discussed herein in some examples of implementation.
Although various embodiments and examples have been presented, this was for
the
purpose of describing, but not limiting, the invention. Various modifications
and
enhancements will become apparent to those of ordinary skill in the art and
are within
the scope of the invention, which is defined by the appended claims.
58
CA 3012659 2018-07-26
