Note: Descriptions are shown in the official language in which they were submitted.
TRACK SYSTEM FOR A VEHICLE
FIELD
This disclosure relates generally to off-road vehicles (e.g., all-terrain
vehicles
(ATVs), agricultural vehicles, etc.) and, more particularly, to track systems
for
such vehicles.
BACKGROUND
Certain off-road vehicles may be equipped with track systems which enhance
their traction and/or floatation on soft, slippery and/or irregular grounds
(e.g., soil,
mud, sand, ice, snow, etc.) on which they operate.
For example, an all-terrain vehicle (ATV) may be equipped with track systems
in
place of ground-engaging wheels with tires for which it may have been
originally
designed. While this may help for traction and/or floatation of the ATV, the
track
systems may experience issues because they are different (e.g., in geometry,
size, structure, behavior, etc.) from the ground-engaging wheels for which the
ATV may have been originally designed. For instance, the ATV may be set up so
that its ground-engaging wheels are cambered (e.g., have a positive or
negative
camber), but the track systems may not account for this, which may
detrimentally
affect performance of the track systems, such as by altering a "contact patch"
(i.e., an area of contact) of each track system with the ground in ways that
can be
adverse to steerability and/or manoeuvrability of the ATV.
Similar considerations may arise for track systems of other types of off-road
vehicles (e.g., agricultural vehicles, etc.) in certain situations.
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For these and other reasons, there is a need to improve track systems for
vehicles.
SUMMARY
According to various aspects, this disclosure relates to a track system for a
vehicle in which the track system is configured to enhance traction,
floatation,
and/or other aspects of its performance, such as, for example, to maintain
proper
contact with the ground (e.g., even if it is cambered) and/or to better absorb
shocks when it encounters obstacles on the ground.
For example, according to an aspect, this disclosure relates to a track system
for
a vehicle. The track system includes a track including a ground-engaging outer
surface for engaging the ground and an inner surface opposite to the ground-
engaging outer surface; and a track-engaging assembly configured to move the
track around the track-engaging assembly. An area of contact between the track-
engaging assembly and a bottom run of the track spans less than half of a
width
of the track in a widthwise direction of the track system at a cross-section
of the
track-engaging assembly where the track-engaging assembly contacts the
bottom run of the track.
According to another aspect, this disclosure relates to a track system for a
vehicle. The track system includes a track including a ground-engaging outer
surface for engaging the ground and an inner surface opposite to the ground-
engaging outer surface; and a track-engaging assembly configured to move the
track around the track-engaging assembly. An area of contact between the track-
engaging assembly and a bottom run of the track spans less than half of a
width
of the track in a widthwise direction of the track system at every cross-
section of
the track-engaging assembly where the track-engaging assembly contacts the
bottom run of the track.
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According to another aspect, this disclosure relates to a track system for a
vehicle. The track system includes a track including a ground-engaging outer
surface for engaging the ground and an inner surface opposite to the ground-
engaging outer surface; and a track-engaging assembly configured to move the
track around the track-engaging assembly. The track-engaging assembly
includes a drive wheel for driving the track and a plurality of idler wheels
contacting a bottom run of the track. An area of contact between the track-
engaging assembly and a bottom run of the track spans less than half of a
width
of the track in a widthwise direction of the track system at cross-sections of
the
track-engaging assembly where respective ones of the idler wheels contact the
bottom run of the track.
According to another aspect, this disclosure relates to a track system for a
vehicle. The track system includes a track including a ground-engaging outer
surface for engaging the ground and an inner surface opposite to the ground-
engaging outer surface; and a track-engaging assembly configured to move the
track around the track-engaging assembly. The track-engaging assembly
includes a drive wheel for driving the track, a plurality of idler wheels
contacting a
bottom run of the track, and a frame supporting the idler wheels. The frame
includes a longitudinal base carrying the idler wheels. A given one of the
idler
wheels is contained within the longitudinal base of the frame of the track-
engaging assembly in a widthwise direction of the track system.
According to another aspect, this disclosure relates to a track system for a
vehicle. The track system includes a track including a ground-engaging outer
surface for engaging the ground and an inner surface opposite to the ground-
engaging outer surface; and a track-engaging assembly configured to move the
track around the track-engaging assembly. The track-engaging assembly
includes a drive wheel for driving the track and a plurality of idler wheels
contacting a bottom run of the track. The idler wheels include a leading idler
wheel and a trailing idler wheel spaced from one another in a longitudinal
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direction of the track system. The leading idler wheel and the trailing idler
wheel
are centrally disposed in a widthwise direction of the track system such that
each
of the leading idler wheel and the trailing idler wheel overlaps a centerline
of the
track that bisects the track in the widthwise direction of the track.
According to another aspect, this disclosure relates to a track system for a
vehicle. The track system includes: a track including a ground-engaging outer
surface for engaging the ground and an inner surface opposite to the ground-
engaging outer surface; and a track-engaging assembly configured to move the
track around the track-engaging assembly. The track-engaging assembly
includes a track-engaging member engaging a bottom run of the track at a cross-
section of the track-engaging assembly and is free of contact with the bottom
run
of the track from the track-engaging member to lateral edges of the track at
the
cross-section of the track-engaging assembly.
According to another aspect, this disclosure relates to a track system for a
vehicle. The track system includes: a track including a ground-engaging outer
surface for engaging the ground and an inner surface opposite to the ground-
engaging outer surface; and a track-engaging assembly configured to move the
track around the track-engaging assembly. The track-engaging assembly is
configured such that every part of the track-engaging assembly that contacts a
bottom run of the track remains in contact with the bottom run of the track
even if
the track system is cambered.
According to another aspect, this disclosure relates to a track system for a
vehicle. The track system includes: a track including a ground-engaging outer
surface for engaging the ground and an inner surface opposite to the ground-
engaging outer surface; and a track-engaging assembly configured to move the
track around the track-engaging assembly. The track-engaging assembly
comprises a drive wheel for driving the track and a plurality of idler wheels
contacting a bottom run of the track. The track-engaging assembly is
configured
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such that every idler wheel remains in contact with the bottom run of the
track
even if the track system is cambered.
These and other aspects of this disclosure will now become apparent to those
of
ordinary skill in the art upon review of the following description of
embodiments in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
A detailed description of embodiments is provided below, by way of example
only, with reference to the accompanying drawings, in which:
Figures 1A and 1B show an example of an embodiment of an all-terrain vehicle
(ATV) comprising track systems;
Figures 2A and 2B show the ATV equipped with ground-engaging wheels instead
of the track systems;
Figures 3 and 4 respectively show perspective and side views of a track system
of the track systems;
Figures 5 and 6 respectively show perspective and side views of the track
system without its track;
Figures 7 and 8 show perspective views of a segment of the track of the track
system, which depict features of an inner side and a ground-engaging outer
side
of the track;
Figure 9 shows a side view of the track of the track system;
Figure 10 shows a plan view of the inner side of the track of the track
system;
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Figure 11 shows a plan view of the outer side of the track of the track
system;
Figures 12 and 13 show cross-sectional views of the track of the track system;
Figures 14 and 15 show cross-sectional views of a variant of the track of the
track system;
Figures 16 to 20 show views of a segment of a variant of the track;
Figures 21A and 21B show end views of the track system without its track,
without camber and with camber;
Figures 22A and 22B show end views of a conventional track system without its
track, without camber and with camber;
Figure 23 shows a leading idler wheel and a segment of a track of a
conventional
track system;
Figure 24 shows a leading idler wheel and a segment of the track of the track
system;
Figures 25 and 26 show the leading idler wheel and the segment of the track of
the track system with and without presence of an obstacle;
Figure 27 shows an example of another embodiment of the track system;
Figures 28 and 29 show views of the track system of Figure 27;
Figure 30 shows a view of the track system of Figure 27 without its track;
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Figures 31A and 31C show a cross-sectional view of the leading idler wheel in
contact with the track according to a various embodiment of the track system;
Figures 32 and 33 show a cross-sectional view of the leading idler wheel in
contact with the track and of roller wheels in contact with the track
according to a
various embodiment of the track system;
Figure 34 shows an example of an embodiment of a track system of a
snowmobile;
Figure 35 shows an example of an embodiment of a track system of a snow bike;
and
Figure 36 shows the snow bike of Figure 35 when it is converted to be equipped
with front and rear wheels.
It is to be expressly understood that the description and drawings are only
for the
purpose of illustrating certain embodiments, are an aid for understanding, and
are not limiting.
DETAILED DESCRIPTION OF EMBODIMENTS
Figures 1A and 1B show an example of an embodiment of a tracked vehicle 10
comprising a plurality of track systems 161-164. In this embodiment, the
vehicle
10 is an all-terrain vehicle (ATV), which is a small open vehicle designed to
travel
off-road on a variety of terrains, including roadless rugged terrain, for
recreational, utility and/or other purposes.
In this embodiment, the AN 10 comprises a frame 11, a powertrain 12, a
steering system 17, a suspension 19, the track systems 161-164, a seat 18, and
a
user interface 20, which enable a user of the AN to ride the AN 10 on the
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ground. The AN 10 has a longitudinal direction, a widthwise direction, and a
height direction.
As further discussed later, in this embodiment, each of the track systems 161-
164
is configured to enhance traction, floatation, and/or other aspects of its
performance, including to maintain proper contact with the ground (e.g., even
if it
cambered) and/or to better absorb shocks when it encounters obstacles on the
ground.
The powertrain 12 is configured for generating motive power and transmitting
motive power to the track systems 161-164 to propel the AN 10 on the ground.
To that end, the powertrain 12 comprises a prime mover 14, which is a source
of
motive power that comprises one or more motors. For example, in this
embodiment, the prime mover 14 comprises an internal combustion engine. In
other embodiments, the prime mover 14 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 14 is in a
driving relationship with one or more of the track systems 161-164. That is,
the
powertrain 12 transmits motive power generated by the prime mover 14 to one or
more of the track systems 161-164 (e.g., via a transmission and/or a
differential)
in order to drive (i.e., impart motion to) these one or more of the track
systems
161-162.
The steering system 17 is configured to enable the user to steer the AN 10 on
the ground. To that end, the steering system 17 comprises a steering device 13
that is operable by the user to direct the AN 10 along a desired course on the
ground. In this embodiment, the steering device 13 comprises handlebars. The
steering device 13 may comprise a steering wheel or any other steering
component that can be operated by the user to steer the AN 10 in other
embodiments. The steering system 17 responds to the user interacting with the
steering device 13 by turning some of the track systems 161-164 to change
their
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orientation relative to the frame 11 of the ATV 10 in order to cause the ATV
10 to
move in a desired direction. In this example, front ones of the track systems
161-
164 are steerable (i.e., turnable) in response to input of the user at the
steering
device 13 to change their orientation relative to the frame 11 of the ATV 10
in
order to steer the ATV 10 on the ground. More particularly, in this example,
each
of the front ones of the track systems 161-164 is pivotable about a steering
axis
29 of the ATV 10 in response to input of the user at the steering device 10 in
order to steer the ATV 10 on the ground. Rear ones of the track systems 161-
164
are not turned relative to the frame 11 of the ATV 10 by the steering system
17.
The suspension 19 is connected between the frame 11 and the track systems
161-164t0 allow relative motion between the frame 11 and the track systems 161-
164 as the ATV 10 travels on the ground. The suspension 19 enhances handling
of the ATV 10 on the ground by absorbing shocks and helping to maintain
traction between the track systems 161-164 and the ground. The suspension 19
may comprise an arrangement of springs and dampers. A spring may be a coil
spring, a leaf spring, a gas spring (e.g., an air spring), or any other
elastic object
used to store mechanical energy. A damper (also sometimes referred to as a
"shock absorber") may be a fluidic damper (e.g., a pneumatic damper, a
hydraulic damper, etc.), a magnetic damper, or any other object which absorbs
or
dissipates kinetic energy to decrease oscillations. In some cases, a single
device
may itself constitute both a spring and a damper (e.g., a hydropneumatic,
hydrolastic, or hydragas suspension device).
In this embodiment, the seat 18 is a straddle seat and the ATV 10 is usable by
a
single person such that the seat 18 accommodates only that person driving the
ATV 10. In other embodiments, the seat 18 may be another type of seat, and/or
the ATV 10 may be usable by two individuals, namely one person driving the
ATV 10 and a passenger, such that the seat 18 may accommodate both of these
individuals (e.g., behind one another or side-by-side) or the ATV 10 may
comprise an additional seat for the passenger. For example, in other
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CA 2985794 2017-11-15
embodiments, the ATV 10 may be a side-by-side ATV, sometimes referred to as
a "utility terrain vehicle" or "utility task vehicle" (UTV).
The user interface 20 allows the user to interact with the ATV 10. More
particularly, the user interface 20 comprises an accelerator, a brake control,
and
the steering device 13 that are operated by the user to control motion of the
ATV
on the ground. 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 systems 161-164 engage the ground to provide traction to the ATV 10.
More particularly, in this example, the front ones of the track systems 161-
164
provide front traction to the ATV 10 while the rear ones of the track systems
161-
164 provide rear traction to the ATV 10.
In this embodiment, as shown in Figures 2A and 2B, each of the track systems
161-164 is mounted in place of a respective one of a plurality of ground-
engaging
wheels 151-154 having tires with which the ATV 10 may equipped. Basically, in
this embodiment, the track systems 161-164 may be used to convert the ATV 10
from a wheeled vehicle into a tracked vehicle, thereby enhancing its traction
and
floatation on the ground.
With additional reference to Figures 3 to 6, in this embodiment, each track
system 16, comprises a track 41 and a track-engaging assembly 22 to move the
track 41 around the track-engaging assembly 22. In this example, the track-
engaging assembly 22 comprises a frame 44 and a plurality of track-contacting
wheels which includes a drive wheel 42 and a plurality of idler wheels 501-
504.
The track system 16, has a front longitudinal end 57 and a rear longitudinal
end
59 that define a length of the track system 16,. A width of the track system
16, is
defined by a width WT of the track 41. An envelope of the track system 16, is
CA 2985794 2017-11-15
defined by a length of the track 41. The track system 16; has a longitudinal
direction, a widthwise direction (i.e., a lateral direction), and a height
direction.
The track 41 engages the ground to provide traction to the ATV 10. The length
of
the track 41 allows the track 41 to be mounted around the track-engaging
assembly 22. In view of its closed configuration without ends that allows it
to be
disposed and moved around the track-engaging assembly 22, the track 41 can
be referred to as an "endless" track. Referring additionally to Figures 7 to
11, the
track 41 comprises an inner side 45 facing the wheels 42, 501-504 and a ground-
engaging outer side 47 opposite the inner side 45 for engaging the ground.
Lateral edges 631, 632 of the track 41 define the track's width WT. The track
41
has a top run 65 which extends between the longitudinal ends 57, 59 of the
track
system 16, and over the wheels 42, 501-504 and a bottom run 66 which extends
between the longitudinal ends 57, 59 of the track system 16, and under the
wheels 42, 501-504. The bottom run 66 of the track 41 defines an area of
contact
58 of the track 41 with the ground which generates traction and bears a
majority
of a load on the track system 16õ and which will be referred to as a "contact
patch" of the track 41 with the ground. The track 41 has a longitudinal
direction, a
widthwise direction (i.e., a lateral direction), and a thickness direction.
The track 41 is elastomeric in that it comprises elastomeric material allowing
it to
flex around the wheels 42, 501-504. The elastomeric material of the track 41
can
include any polymeric material with suitable elasticity. In this embodiment,
the
elastomeric material includes rubber. Various rubber compounds may be used
and, in some cases, different rubber compounds may be present in different
areas of the track 41. In other embodiments, the elastomeric material of the
track
41 may include another elastomer in addition to or instead of rubber (e.g.,
polyurethane elastomer). The track 41 can be molded into shape in a mold by a
molding process during which its elastomeric material is cured.
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More particularly, the track 41 comprises an elastomeric belt-shaped body 36
underlying its inner side 45 and its ground-engaging outer side 47. In view of
its
underlying nature, the body 36 can be referred to as a "carcass". The carcass
36
comprises elastomeric material 37 which allows the track 41 to flex around the
wheels 42, 501-504.
As shown in Figure 12, in some embodiments, the carcass 36 may comprise a
plurality of reinforcements 681-68R (e.g., reinforcing layers) embedded in its
elastomeric material 37. One example of a reinforcement 68, is a layer of
reinforcing cables 381-38c that are adjacent and generally parallel to one
another. For instance, the reinforcing cables 381-38c may extend in the
longitudinal direction of the track 41 to enhance strength in tension of the
track
41 along its longitudinal direction. In some cases, a reinforcing cable may be
a
cord or wire rope including a plurality of strands or wires. In other cases, a
reinforcing cable 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). Another example of a reinforcement 68, is a layer of reinforcing
fabric
40. Reinforcing fabric comprises 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
at
least some of the elongated fabric elements extend transversally to the
longitudinal direction of the track 41 to have a reinforcing effect
transversally to
the longitudinal direction of the track 41. For instance, a layer of
reinforcing fabric
may comprise a ply of reinforcing woven fibers (e.g., nylon fibers or other
synthetic fibers). Various other types of reinforcements may be provided in
the
carcass 36 in other embodiments.
The carcass 36 may be molded into shape in the track's molding process during
which its elastomeric material 37 is cured. For example, in some embodiments,
layers of elastomeric material providing the elastomeric material 37 of the
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carcass 36, the reinforcing cables 381-38c and the layer of reinforcing fabric
40
may be placed into the mold and consolidated during molding.
In this embodiment, the inner side 45 of the track 41 comprises an inner
surface
32 of the carcass 36 and a plurality of wheel-contacting projections 481-48N
that
project from the inner surface 32 to contact at least some of the wheels 42,
501-
504 and that are used to do at least one of driving (i.e., imparting motion
to) the
track 41 and guiding the track 41. In that sense, the wheel-contacting
projections
481-48N can be referred to as "drive/guide projections", meaning that each
drive/guide projection is used to do at least one of driving the track 41 and
guiding the track 41. Also, such drive/guide projections are sometimes
referred to
as "drive/guide lugs" and will thus be referred to as such herein. More
particularly, in this embodiment, the drive/guide lugs 481-48N interact with
the
drive wheel 42 in order to cause the track 41 to be driven, and also interact
with
the idler wheels 501-504 in order to guide the track 41 as it is driven by the
drive
wheel 42. The drive/guide lugs 481-48N are thus used to both drive the track
41
and guide the track 41 in this embodiment.
The drive/guide lugs 481-48N are spaced apart along the longitudinal direction
of
the track 41. In this case, the drive/guide lugs 481-48N are arranged in a
plurality
of rows that are spaced apart along the widthwise direction of the track 41.
The
drive/guide lugs 481-48N may be arranged in other manners in other
embodiments (e.g., a single row or more than two rows). Each of the
drive/guide
lugs 481-48N is an elastomeric drive/guide lug in that it comprises
elastomeric
material 67. The drive/guide lugs 481-48N can be provided and connected to the
carcass 36 in the mold during the track's molding process.
The ground-engaging outer side 47 of the track 41 comprises a ground-engaging
outer surface 31 of the carcass 36 and a plurality of traction projections 611-
61m
that project from the outer surface 31 and engage and may penetrate into the
ground to enhance traction. The traction projections 611-61m, which can
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sometimes be referred to as "traction lugs" or "traction profiles", are spaced
apart
in the longitudinal direction of the track system 16,. The ground-engaging
outer
side 47 comprises a plurality of traction-projection-free areas 71 1-71F
(i.e., areas
free of traction projections) between successive ones of the traction
projections
611-61m. In this example, each of the traction projections 611-61m is an
elastomeric traction projection in that it comprises elastomeric material 69.
The
traction projections 611-61m can be provided and connected to the carcass 36
in
the mold during the track's molding process.
.. Each traction projection 611 extends transversally to the longitudinal
direction of
the track 41. That is, the traction projection 61, has a longitudinal axis 54
extending transversally to the longitudinal direction of the track 41. In this
example, the longitudinal axis 54 of the traction projection 61, is
substantially
parallel to the widthwise direction of the track 41. In other examples, the
longitudinal axis 54 of the traction projection 61, may be transversal to the
longitudinal direction of the track 41 without being parallel to the widthwise
direction of the track 41. The traction projections 611-61m may be configured
in
various other ways in other embodiments.
In this example, the carcass 36 has a thickness Tc which is relatively small.
The
thickness Tc of the carcass 36 is measured from the inner surface 32 to the
ground-engaging outer surface 31 of the carcass 36 between longitudinally-
adjacent ones of the traction projections 611-61m. For example, in some
embodiments, the thickness Tc of the carcass 36 may be no more than 0.250
inches, in some cases no more than 0.240 inches, in some cases no more than
0.230 inches, in some cases no more than 0.220 inches, in some cases no more
than 0.210 inches, in some cases no more than 0.200 inches, and in some cases
even less (e.g., 0.180 or 0.170 inches). The thickness Te of the carcass 36
may
have any other suitable value in other embodiments.
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In this embodiment, as shown in Figures 12 and 13, the track 41 is free of
transversal stiffening rods embedded in its elastomeric material. That is, the
track
41 does not comprise transversal stiffening rods embedded in its elastomeric
material and extending transversally to its longitudinal direction. Figures 14
and
15 shows a variant in which the track 41 may comprise transversal stiffening
rods
531-53m embedded in its elastomeric material and extending transversally to
its
longitudinal direction in other embodiments. This absence of transversal
stiffening rods in some embodiments, such as shown in Figures 12 and 13,
makes the track 41 more flexible in its widthwise direction than if the track
41 had
the transversal stiffening rods 531-53m but was otherwise identical.
Figures 16 to 20 show an example of another embodiment of the track 41 which
comprises bent lateral edge portions 641, 642 adjacent its lateral edges 631,
632
to facilitate steering of the track system 16 on the ground, by making the
contact
patch 58 smaller. For instance, in some embodiments, this may be used for the
front ones of the track systems 161-164 More particularly, the carcass 36 of
the
track 41 of the track system 16, is bent inwardly proximate the lateral edges
631,
632 of the track 41 such that its inner surface 32 and ground-engaging outer
surface 31 are bent inwardly.
The track 41 may be constructed in various other ways in other embodiments.
For example, in some embodiments, the track 41 may comprise a plurality of
parts (e.g., rubber sections) interconnected to one another in a closed
configuration, the track 41 may have recesses or holes that interact with the
drive
wheel 42 in order to cause the track 41 to be driven (e.g., in which case the
drive/guide lugs 481-48N may be used only to guide the track 41 without being
used to drive the track 41), and/or the ground-engaging outer side 47 of the
track
41 may comprise various patterns of traction projections.
The drive wheel 42 is rotatable about an axis of rotation 49 for driving the
track
41 in response to rotation of an axle 21 of the ATV. In this example, the axis
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CA 2985794 2017-11-15
rotation 49 corresponds to an axis of rotation 79 of the axle 21 of the ATV
10.
More particularly, in this example, the drive wheel 42 has a hub which is
mounted
to the axle 21 of the ATV 10 such that power generated by the prime mover 14
and delivered over the powertrain 12 of the ATV 10 rotates the axle 21, which
rotates the drive wheel 42, which imparts motion of the track 41. In this
embodiment in which the track system 16, is mounted where a ground-engaging
wheel 15; could otherwise be mounted, the axle 21 of the ATV 10 is capable of
rotating the drive wheel 42 of the track system 16, or the ground-engaging
wheel
15.
In this embodiment, the drive wheel 42 comprises a drive sprocket engaging the
drive/guide lugs 481-48N of the inner side 45 of the track 41 in order to
drive the
track 41. In this case, the drive sprocket 42 comprises a plurality of teeth
461-46T
distributed circumferentially along its rim to define a plurality of lug-
receiving
spaces therebetween that receive the drive/guide lugs 481-48N of the track 41.
The drive wheel 42 may be configured in various other ways in other
embodiments. For example, in embodiments where the track 41 comprises
recesses or holes, the drive wheel 42 may have teeth that enter these recesses
or holes in order to drive the track 41. As yet another example, in some
embodiments, the drive wheel 42 may frictionally engage the inner side 45 of
the
track 41 in order to frictionally drive the track 41.
The idler wheels 501-504 are not driven by power supplied by the prime mover
14, but are rather used to do at least one of supporting part of the weight of
the
ATV 10 on the ground via the track 41, guiding the track 41 as it is driven by
the
drive wheel 42, and tensioning the track 41. More particularly, in this
embodiment, the idler wheels 501, 504 are respectively a front idler wheel (a
leading idler wheel) and a rear idler wheel (a trailing idler wheel) that
maintain the
track 41 in tension, and can help to support part of the weight of the ATV 10
on
the ground via the track 41. The idler wheels 502, 503 are roller wheels that
roll
on the inner side 45 of the track 41 along the bottom run 66 of the track 41
to
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apply the bottom run 66 on the ground. The idler wheels 501-504 move on an
idler
wheel path 55 of the inner surface 32 of the carcass 36 of the track 41. The
idler
wheel path 55 extends between respective ones of the drive/guide lugs 481-48N
to allow these lugs to guide motion of the track 41. The idler wheels 501-504
may
.. be arranged in other configurations and/or the track system 16; may
comprise
more or less idler wheels in other embodiments.
In this embodiment, the bottom run 66 of the track 41 has a geometry
configured
to help traction and maneuverability of the track system 16,. More
particularly, in
this embodiment, the front idler wheel 501 is adjacent to the front
longitudinal end
57 of the track system 16,-, the rear idler wheel 504 is adjacent to the rear
longitudinal end 59 of the track system 16,, and the roller wheels 502-503 are
located between the front idler wheel 501 and the rear idler wheel 504 in the
longitudinal direction of the track system 16õ such that the bottom run 66 of
the
track 41 comprises a front segment 105 under the front idler wheel 50i, a rear
segment 109 under the rear idler wheel 504, and an intermediate segment 107
under the roller wheels 502-503 and extending lower than a given one of the
front
segment 105 and the rear segment 109 of the bottom run 66 of the track 44. In
this example, the intermediate segment 107 of the bottom run 66 of the track
41
extends lower than each of the front segment 105 and the rear segment 109 of
the bottom run 66 of the track 44. Also, in this example, the intermediate
segment 107 of the bottom run 66 of the track 41 is generally flat and
parallel to
the ground between the roller wheels 502-503.
As the front and rear idler wheels 501 and 504 maintain the track 41 in
tension
and may, at least at rest, not apply the track to the ground, the front and
rear idler
wheels 501 and 504 may be elevated relative to the ground. For example, in
this
embodiment, a bottom 101 of the front idler wheel 501 is higher than a bottom
102 of a frontmost one of the roller wheels 502-503 and bottom 104 of a
rearmost
one of the roller wheels 502-503. Also, in this embodiment, the bottom 101 of
the
front idler wheel 501 is higher than a bottom 104 of the rear idler wheels 504
17
CA 2985794 2017-11-15
Thus, in this example, a height relative to the ground H, of the front idler
wheel
501 may be greater than a height relative to the ground H1 of the rear idler
wheel
504. To manage the traction and the maneuverability of each of the track
systems
161-164, as the front ones of the track systems 161-164 may require a
different
amount of traction and/or a different degree of maneuverability than the rear
ones of the track systems 161-164, their respective geometry may differ.
In this embodiment, a distance between the axis of rotation 49 of the drive
wheel
42 and an axis of rotation 601 of the front idler wheel 501 in the
longitudinal
direction of the track system 16, is different from a distance between the
axis of
rotation 49 of the drive wheel 42 and an axis of rotation 604 of the rear
idler
wheel 504 in the longitudinal direction of the track system 16,. In this
example, the
roller wheels 502-503 of the front ones of the track systems 161-164 may be
closer
one to another than the roller wheels 502-503 of the rear ones of the track
systems 161-164. Also, in this example, for the front ones of the track
systems
161-164, the roller wheels 502-503 may be located closer the rear idler wheel
504
than to the front idler wheel 501, while for the rear ones of the track
systems 161-
164, the roller wheels 502-503 may be closer to the front idler wheel 501 than
to
the rear idler wheel 504.
The frame 44 supports components of the track system 16,, including the idler
wheels 501-504. More particularly, in this embodiment, the front and rear
idler
wheels 501, 504 are respectively mounted to the frame 44 in a front
longitudinal
end region of the frame 44 proximate the front longitudinal end 57 of the
track
system 16, and in a rear longitudinal end region of the frame 44 proximate the
rear longitudinal end 59 of the track system 16,. The roller wheels 502, 503
are
mounted to the frame 44 in a central region of the frame 44 between the front
idler wheel 501 and the rear idler wheel 504. Each of the roller wheels 502,
503
may be rotatably mounted directly to the frame 44 or may be rotatably mounted
to a link which is pivotally mounted to the frame 44 to which is rotatably
mounted
an adjacent one of the roller wheels 502, 502, thus forming a "tandem".
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CA 2985794 2017-11-15
In this embodiment, the frame 44 comprises a longitudinal base 90 that is
elongated in the longitudinal direction of the track system 16, and carries
the idler
wheels 501-504 and an upper part 64 that extends upwardly from the
longitudinal
base 90. In this example, the upper part 64 of the frame 44 comprises arms
431,
432 that converge upwardly from the longitudinal base 90.
The frame 44 is supported at a support area 39. More specifically, in this
case,
the frame 44 is supported by the axle 21 of the ATV 10 to which is coupled the
drive wheel 42, such that the support area 39 is intersected by the axis of
rotation
49 of the drive wheel 42.
In this embodiment, the frame 44 is pivotable about a pivot axis 51 to
facilitate
motion of the track system 16, on uneven terrain and enhance its traction on
the
ground. More particularly, in this embodiment, the pivot axis 51 corresponds
to
the axis of rotation 49 of the drive wheel 42 and the frame 44 can pivot about
the
axle of the ATV 10 to which the drive wheel 42 is coupled. In other
embodiments,
the pivot axis 51 of the frame 44 may be located elsewhere (e.g., lower) than
the
axis of rotation 49 of the drive wheel 42. In yet other embodiments, the frame
44
may not be pivotable.
Also, in this embodiment, the track system 16, comprises an anti-rotation
connector 52 to limit a pivoting movement of the track system 16; relative to
the
frame 11 of the ATV 10. In this example, the anti-rotation connector 52
comprises a spring and a damper and is connected between the frame 44 of the
track system 16, and the frame 11 of the ATV 10 (e.g., via one or more
mounting
brackets and/or fasteners).
With additional reference to Figures 21A and 21B, in this embodiment, the
track-
engaging assembly 22 is configured to engage the bottom run 66 of the track 41
narrowly at certain locations as this may help to enhance performance of the
19
CA 2985794 2017-11-15
track system 16. For example, this may help to maintain the contact patch 58
of
the track 41 with the ground, even if the track system 16, is cambered (e.g.,
a
ground-engaging wheel 15; replaced by the track system 16; had a camber, i.e.,
a
positive or negative camber, that is inherited by the track system 16i). This
may
also help for shock absorption when the track 41 encounters an obstacle on the
ground (e.g., a rock, debris, an abrupt change in ground level, etc.).
An area of contact 70 between the track-engaging assembly 22 and the bottom
run 66 of the track 41 is thus narrow in the widthwise direction of the track
system 16; at one or more cross-sections of the track-engaging assembly 22
where the track-engaging assembly 22 contacts the bottom run 66 of the track
41. These one or more cross-sections of the track-engaging assembly 22 where
it contacts the bottom run 66 of the track 41 are normal to the longitudinal
direction of the track system 16, and will be referred to as one or more
"track-
contacting" cross-sections of the track-engaging assembly 22. The area of
contact 70 between the track-engaging assembly 22 and the bottom run 66 of the
track 41 encompasses every part of the track-engaging assembly 22 that
contacts the bottom run 66 of the track 41. In this example, the area of
contact 70
between the track-engaging assembly 22 and the bottom run 66 of the track 41
thus encompasses an area of contact between each of the idler wheels 501-504
and the bottom run 66 of the track 41.
In this embodiment, the area of contact 70 between the track-engaging assembly
22 and the bottom run 66 of the track 41 is narrow in the widthwise direction
of
the track system 16, at track-contacting cross-sections 711-714 of the track-
engaging assembly 22 where the idler wheels 501-504 contact the bottom run 66
of the track 41. In this example, the area of contact 70 between the track-
engaging assembly 22 and the bottom run 66 of the track 41 is narrow in the
widthwise direction of the track system 16, at every track-contacting cross-
section
(i.e., at all track-contacting cross-sections) of the track-engaging assembly
22.
CA 2985794 2017-11-15
More particularly, in this embodiment, at every track-contacting cross-
section,
including each of the track-contacting cross-sections 711-714, of the track-
engaging assembly 22, the area of contact 70 between the track-engaging
assembly 22 and the bottom run 66 of the track 41 spans less than half, in
some
cases no more than 40%, in some cases no more than 30%, and in some cases
no more than 20% of the width WT of the track 41 in the widthwise direction of
the
track system 16. That is, a dimension CT of the area of contact 70 between the
track-engaging assembly 22 and the bottom run 66 of the track 41 in the
widthwise direction of the track system 16, at every track-contacting cross-
section
of the track-engaging assembly 22 is less than half, in some cases no more
than
40%, in some cases no more than 30%, and in some cases no more than 20% of
the width WT of the track 41.
Also, in this embodiment, at every track-contacting cross-section, including
each
of the track-contacting cross-sections 711-714, of the track-engaging assembly
22, the area of contact 70 between the track-engaging assembly 22 and the
bottom run 66 of the track 41 is contained within (i.e., is not located
beyond) the
longitudinal base 90 of the frame 44 of the track system 16, in the widthwise
direction of the track system 16,. More particularly, in this embodiment, the
area
of contact 70 between the track-engaging assembly 22 and the bottom run 66 of
the track 41 spans no more than a width WF of the longitudinal base 90 of the
frame 44 of the track system 16, in the widthwise direction of the track
system
16,. In this example, the area of contact 70 between the track-engaging
assembly
22 and the bottom run 66 of the track 41 spans less than the width WF of the
longitudinal base 90 of the frame 44 of the track system 16, in the widthwise
direction of the track system 16,. For instance, in some embodiments, the area
of
contact 70 between the track-engaging assembly 22 and the bottom run 66 of the
track 41 may span less than three-quarters, in some cases less than two-
thirds,
and in some cases less than half of the width WF of the longitudinal base 90
of
the frame 44 of the track system 16, in the widthwise direction of the track
system
16,.
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CA 2985794 2017-11-15
Furthermore, in this embodiment, at every track-contacting cross-section,
including each of the track-contacting cross-sections 711-714, of the track-
engaging assembly 22, the area of contact 70 between the track-engaging
assembly 22 and the bottom run 66 of the track 41 is continuous (i.e.,
uninterrupted) in the widthwise direction of the track system 16,. That is, at
track-
contacting every cross-section of the track-engaging assembly 22, the area of
contact 70 between the track-engaging assembly 22 and the bottom run 66 of the
track 41 is defined by a single part of the track-engaging assembly 22 that
continuously extends in contact with the bottom run 66 of the track 41 without
interruption in the widthwise direction of the track system 161.
Thus, in this embodiment, at every track-contacting cross-section, including
each
of the track-contacting cross-sections 711-714, of the track-engaging assembly
22, the track-engaging assembly 22 comprises a track-engaging member 72
engaging the bottom run 66 of the track 41 and is free of contact with (i.e.,
does
not contact) the bottom run 66 of the track 41 from the track-engaging member
72 to the lateral edges 631, 632 of the track 41. For instance, in this
embodiment,
the track-engaging member 72 is a given one of the idler wheels 501-504. The
track-engaging assembly 22 is free of (i.e., has no) track-engaging structure
spaced from the given one of the idler wheels 501-504 in the widthwise
direction
of the track system 16, and contacting the bottom run 66 of the track 41.
More particularly, in this embodiment, the idler wheels 501-504 are centrally
disposed in the widthwise direction of the track system 16,. Each of the idler
wheels 501-504 overlaps a centerline 75 of the track 41 that bisects the
track's
width WT. The idler wheels 501-504 are arranged in a single line following the
centerline 75 of the track 1 in the longitudinal direction of the track system
16.
Also, the idler wheels 501-504 are aligned with the drive wheel 42 in the
widthwise direction of the track system 16,.
22
CA 2985794 2017-11-15
In this embodiment, the idler wheels 501-504 are contained within the
longitudinal
base 90 of the frame 44 of the track-engaging assembly 22 in the widthwise
direction of the track system 16,. More particularly, in this embodiment, the
longitudinal base 90 of the frame 44 comprises voids 931-93v for containing
.. respective ones of the idler wheels 501-504. In some examples, each of the
voids
931-934 may contain only a single one of the idler wheels 501-504. In other
examples, a given one of the voids 931-93v may contain at least two of the
idler
wheels 501-504. The voids 931-93v are aligned with the drive wheel 42 in the
widthwise direction of the track system 16,. In other embodiments, the
longitudinal base 90 of the frame 44 of the track system 16, may comprise only
a
single void containing all of the idler wheels 501-504. In some cases, this
may
allow the track system 16, to be reduced in width, thus allowing a lower width
to
the vehicle 10.
As shown in Figures 21A and 21B, in this embodiment, the track-engaging
assembly 22 is configured such that every part of the track-engaging assembly
22 that contacts the bottom run 66 of the track 41 remains in contact with the
bottom run 66 of the track 41 even if the track system 161 is cambered. More
particularly, in this embodiment, the track-engaging assembly 22 is configured
such that every one of the idler wheels 501-504 remains in contact with the
bottom run 66 of the track 41, even if the track system 16, is cambered. This
may
help to maintain the contact patch 58 of the track 41 with the ground and thus
enhance traction. For example, in this embodiment, the track system 16, is
cambered because a ground-engaging wheel 15, replaced by the track system
16, had a camber, i.e., a positive or negative camber, so that, when the track
system 16, is mounted in place of the ground-engaging wheel 15õ the camber is
inherited by the track system 16,.
For instance, in some embodiments, every one of the idler wheels 501-504 may
remain in contact with the bottom run 66 of the track 41 even if the track
system
161 is cambered at a camber angle a of at least 50, in some cases at least
100, in
23
CA 2985794 2017-11-15
some cases at least 15 , in some cases at least 200, and in some cases even
more.
This contrasts with a conventional track system with a wide area of contact
between its track-engaging assembly and a bottom run of its track, an example
of
which is shown in Figures 22A and 22B, where some of its idler wheels and/or
other parts of its track-engaging assembly would not contact the bottom run of
its
track when the conventional track system is cambered.
The area of contact 70 between the track-engaging assembly 22 and the bottom
run 66 of the track 41 being narrow in the widthwise direction of the track
system
16, may also be useful for steerability and/or other aspects of
maneuverability.
For example, in some embodiments, this may be useful when the track system
16, is steered about the steering axis 29. For instance, in some cases, a
stabilization of the vehicle 10 may be improved such as by having the areas of
contact 70 for each of the track systems 161-164 that are more distant in the
widthwise direction of the vehicle 10 relative to a longitudinal centerline 81
of the
vehicle 10. Additionally or alternatively, in some cases, mechanical stresses
in
parts of the track system 16, and/or the vehicle 10, such as the suspension
19,
may be diminished.
In this embodiment, with additional reference to Figures 23, 24 and 26, the
area
of contact 70 between the track-engaging assembly 22 and the bottom run 66 of
the track 41 being narrow in the widthwise direction of the track system 16,
may
help for shock absorption when the track 41 encounters an obstacle 80 on the
ground (e.g., a rock, debris, an abrupt change in ground level, etc.).
More particularly, in this embodiment, this reduces a potential for the track-
engaging assembly 22 to impact the obstacle 80 on the ground when the track
system 16, encounters the obstacle 80 on the ground, and allows a given one of
lateral portions 831, 832 of the track 41 that extend from lateral extremities
of the
24
CA 2985794 2017-11-15
area of contact 70 of 851, 852 between the track-engaging assembly 22 and the
bottom run 66 of the track 41 to the lateral edges 631, 632 of the track 41 to
flex
inwardly and absorb a shock from encountering the obstacle 80 on the ground.
For instance, the track system 16, comprises a stiffer (i.e., more rigid)
ground-
engaging portion 96 having a width WR where the track system 16, is more
exposed to stress occasioned by the obstacle 80 on the ground. The width WR of
the stiffer ground-engaging portion 96 of the track system 16, may be less
than
that of a conventional track system comprising rows of idler wheels that are
.. laterally spaced apart, an example of which is shown in Figure 25, such
that a
narrower extent of the stiffer ground-engaging portion 96 of the track system
16,
diminishes a risk that the obstacle 80 is encountered at the stiffer ground-
engaging portion 96 of the track system 16, and rather increases a likelihood
that
the obstacle 80 is encountered at either one of lateral portions 831, 832 of
the
track 41, which may help for shock absorption by deformation of that impacted
one of the lateral portions 831, 832 of the track 41 which is substantially
free to
bend or otherwise deform as it is uncontacted by the track-engaging assembly
22.
The track system 16, may be implemented in various other ways in other
embodiments.
For example, with additional reference to Figures 27 to 30, in some
embodiments, the area of contact 70 between the track-engaging assembly 22
and the bottom run 66 of the track 41 may be narrow in the widthwise direction
of
the track system 16, at some but not all track-contacting cross-sections of
the
track-engaging assembly 22, such as at one or more of but not all of the track-
contacting cross-sections 711-714 of the track-engaging assembly 22 where the
idler wheels 501-504 contact the bottom run 66 of the track 41.
25
CA 2985794 2017-11-15
In this embodiment, the track-engaging assembly 22 comprises roller wheels
502,
503, 505, 506 and the area of contact 70 between the track-engaging assembly
22
and the bottom run 66 of the track 41 at each of the track-contacting cross-
sections 711, 714 of the track-engaging assembly 22 where a respective one of
the front and rear idler wheels 501, 504 contacts the bottom run 66 of the
track 41
is narrow as discussed above in respect of Figures 21A and 21B, whereas the
area of contact 70 between the track-engaging assembly 22 and the bottom run
66 of the track 41 at each of the track-contacting cross-sections 712, 713 of
the
track-engaging assembly 22 where respective ones of the roller wheels 502,
503,
505, 506 contacts the bottom run 66 of the track 41 is wider.
As best seen in Figures 32 and 33, in this embodiment, a ratio of (1) the
dimension CT of the area of contact 70 between the track-engaging assembly 22
and the bottom run 66 of the track 41 in the widthwise direction of the track
system 16; at each of the track-contacting cross-sections 711, 714 of the
track-
engaging assembly 22 where a respective one of the front and rear idler wheels
501, 504 contacts the bottom run 66 of the track 41 over (2) the dimension CT
of
the area of contact 70 between the track-engaging assembly 22 and the bottom
run 66 of the track 41 at each of the track-contacting cross-sections 712, 713
of
the track-engaging assembly 22 where respective ones of the roller wheels 502,
503, 505, 506 contacts the bottom run 66 of the track 41 is no more than 0.9,
in
some cases no more than 0.8, in some cases no more than 0.7, and in some
cases even less.
In this embodiment, the longitudinal base 90 of the frame 44 comprises the
voids
931, 932 configured to house the leading idler wheel 501 and the trailing
idler
wheel 504, whereas the roller wheels 502, 503, 505, 506 are not housed in a
void
of the frame 44, but rather located outside of the longitudinal base 90 of the
frame 44 and face outer lateral surfaces 981, 982 of the longitudinal base 90
of
the frame 44.
26
CA 2985794 2017-11-15
In some examples, an attachment 95 between each of the roller wheels 502, 503,
505, 506 and the longitudinal base 90 of the frame 44 may be rigid such as to
prevent each pair of the roller wheels 502, 503, 505, 506 to rotate relative
to the
frame 44 of the track system 16,. In other examples, the attachment 95 between
each of the roller wheels 502, 503, 505, 506 and the longitudinal base 90 of
the
frame may be flexible such as to allow each pair of the roller wheels 502,
503,
505, 506 to rotate relative to the frame 44 of the track system 16, to emulate
certain advantages discussed above. In yet other examples, the attachment 95
between each of the roller wheels 502, 503, 505, 506 and the longitudinal base
90
of the frame may be rigid such as to prevent each pair of the roller wheels
502,
503, 505, 506 to rotate relative to the frame 44 of the track system 16,, but
a
material of the roller wheels 502, 503, 505, 506, and/or a geometry of the
roller
wheels 502, 503, 505, 506 combined with a geometry of the inner side 45 of the
track 41 may be such that certain advantages discussed above are replicated.
For example, with additional reference to Figures 31A to 31B, the inner
surface
32 may comprise grooves 821,822 themselves comprising rolling surfaces 841-842
extending longitudinally along the track 41 and the roller wheels 502, 503,
505,
506 may comprise a rolling surface 86 that is curved is such a way that, when
there the track system 16, is cambered, the roller wheels 502, 503, 505, 506
may
be in contact with the rolling surfaces 841-842 when the camber angle a is
less
than a certain value (e.g., 5 , 10 , 15 or 20 ), but at least one of the
roller
wheels 502, 503, 505, 506 may be not be in contact with the rolling surfaces
841-
842 when the camber angle a is more than that certain value.
While in this embodiment the track system 16, is part of the ATV 10, in other
embodiments, a track system constructed according to principles discussed
herein may be used as part of other types of tracked vehicles.
27
CA 2985794 2017-11-15
For example, in some embodiments, as shown in Figure 34, a track system 616
comprising a track 641 constructed according to principles discussed herein
may
be used as part of a snowmobile 610.
As another example, in some embodiments, as shown in Figures 35 and 36, a
track system 716 comprising a track 741 constructed according to principles
discussed herein may be used as part of a snow bike 710. The snow bike 710 is
a motorcycle equipped with a ski system 717 mounted in place of a front wheel
702 of the motorcycle and the track system 716 mounted in place of a rear
wheel
704 of the motorcycle. In this example, the track system 716 also replaces a
rear
suspension unit (e.g., a shock absorber and a swing arm) of the motorcycle.
Basically, the track system 716 converts the motorcycle into a tracked vehicle
for
travelling on snow.
The ATV 10, the snowmobile 610 and the snow bike 710 considered above are
examples of recreational vehicles. While they can be used for recreational
purposes, such recreational vehicles may also be used for utility purposes in
some cases.
Also, while these examples pertain to recreational vehicles, a track system
comprising a track constructed according to principles discussed herein may be
used as part of tracked vehicles other than recreational ones (e.g.,
agricultural
vehicles, construction vehicles, military vehicles, and other off-road
vehicles).
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.
28
CA 2985794 2017-11-15
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
purposes of description but is not limiting. Various modifications and
enhancements will become apparent to those of ordinary skill in the art.
29
CA 2985794 2017-11-15
