Note: Descriptions are shown in the official language in which they were submitted.
Baclcground ox the Invention
The present invention relates to a vehicle
wheel having a rigid rim on which is mounted a pneumatic
wire which essentially comprises rubber or rubber-like
synthetic material, and includes a single or multi-ply
carcass ox metal and/or textile strength carriers; the
carcass is anchored in the tire beads by being looped
around the bead cores. The beads of the tire are
disposed on rim seating surfaces next to the rim
flanges, and the tire wall, in the vicinity of the rim
flanges, extellds laterally outwardly approximately
horizontally, i.e. approximately parallel to the axis
of rotation of thy tire.
A vehicle wheel of this general type, where the
beads of the tire are disposed radially inwardly on the
rim ring, is disclosed, for example, in U.S. Patent
application 431,604 which belongs to the assignee of
the present invention. With this heretofore lcnown
wheel, a belted tire is used as is toe case with cut-
tumor rims where the tire is mounted on the radially outer side of the rim.
It is an object of the present invention to
provide an optimization of the neutral line of the
carcass for as broad a range of vehicle wheels as
possible, especially in the lower sidewall region
I
and in the bead region.
Brief Description of the Drawings
This object, and other objects and advantages of
tune present invention will appear more clearly from
the following specification in conjunction with the
accompanying drawing, in which:
Figure 1 is a partial radial section through
one embodiment of an inventive wheel on which is mount-
Ed a belted tire having a single-ply radial carcass;
Figure 2 shows the neutral line of the
carcass of the tire of Figure 1 in an x, y tire keyword-
Nate system;
Figure 3 shows a ca-tenary-like portion
ox the neutral line of the carcass in two coordinate
systems;
Figure 4 is a partial radial section of
another embodiment of the inventive wheel having mount
Ed thereon a tire which has a diagonal carcass and no
belt, with the neutral line of the carcass being shown
in the right half of the figure;
Figure S it a partial radial section of
another embodiment of the inventive wheel, with a
spacer being disposed between the rim and the tore;
Figure 6 is a partial radial section of
another embodiment of the inventive wheel, with the
tire being mounted radially outwardly on the rim ring;
and
-- 2 --
:~2~30~;)
Figure 7 is a set of curves, with the
curve so representing the neutral line of the
carcass in the bead region of the tire of Figure 6.
Summary of the Invention
By one aspect of this invention, there is
provided a vehicle wheel having a rigid rim
including a rim well and a rim ring with rim
seating surfaces as well as rim flanges; a
pneumatic vehicle tire made essentially of rubber
or rubber-like synthetic material and having bead
regions including beads as well as bead cores that
have a cross-sectional area in the bead regions
mounted on the rim; a carcass of strength carriers;
the carcass, which has a neutral line, being
anchored in beads of the tire by being looped
around bead cores thereof; the beads of the tire
being disposed on the rim seating surfaces located
on said rim ring next -to, and axially inwardly of,
said rim flanges: said tire having sidewalls, each
of which, in the vicinity of one of the rim
flanges, extends axially outwardly from the bead
thereof in an approximately horizontal manner,
i.e., approximately parallel to the axis of
rotation of the tire and the wheel;
the improvement in combination
therewith which comprises: a shape of said rim
seating surfaces and said rim flanges, such that
-- 3 --
B
~2~3~
the path of said neutral line of said carcass, only
in lower tire sidewall regions and in the bead
regions at the level of said rim flanges where
minimal movement of the tire is encountered rather
than when where maximum movement of the tire
prevails with tire flexing and springiness, and
axially outwardly from said rim flange, conforms to
the equation of a catenary curve having a positive
inclination such that curvature of the carcass
neutral line opens radially outwardly and axially
outwardly decreases, and, in the radially inner
portion of said sidewalls, departs from a curve
shape which conforms to the diaphragm theory; at
the transition from said last-mentioned curve shape
to said catenary-like path, the radii of curvature
and the pitches of both of the curves are
identical.
The present invention can be utilized not
only for vehicle wheels on which is mounted a
belted tire having a radial carcass, but also for
tires having a diagonal or biased carcass; the
tires can be provided with or without a belt.
Furthermore, the present invention can be used not
only with vehicle wheels for passenger cars, but
also for wheels of trucks and other vehicles.
The critical feature is that the neutral line
of the carcass, in the lower sidewall region at the
- pa -
,
~2~3~
level of the rim flanges, and laterally outwardly
from the latter, conform to the equation of a
catenary; in the bead region, the neutral line of
the carcass can be adapted to the requirements of a
specific situation The present invention can even
be used with vehicle wheels where the tire is
mounted radially outwardly on the rim, and where
the tire walls, in the vicinity of
- 3b -
I
the rim flanges, extends extremely horizontally toward
the outside.
Thy present invention results in an improvement
of several tire properties. above all, the operating
stability and the service life of the tire in thy bead
region are improved Due to the catenary-like path of
the neutral line of the carcass in the lower sidewall
region, where is produced during rotation of this curve
about the axis of rotation of the wheel (the x-axis)
a surface having the least possible surface area. This
also represents minimum energy; i.e., with every deflect
lion during driving operation from this position of
equilibrium, the tire, after the deflection has been
terminated, returns on its own into the position of
equilibrium. Furthermore, the catenary-like path of
the neutral line of the carcass assures a secure seat
of the tire on the rim, and during manufacture of the
tire there results a sayings in material compared to
heretofore known tires which do not have a minimal
surface of revolution.
Pursuant to specific embodiments of tile present
invention, the beads of the tire may be disposed on
rink soaking surfaces which, on the radially inner
periphery of the rim ring, are located next to pro-
dominantly radially inwardly exuding rim flanges.
The neutral line of the carcass may also conform to
the equation of a catenary in the region ox the tire
_
~LZ~.3~)
beads, and the catenary inn end within the cross-sec-
tonal area of the bead cores spacer may be disposed
between the tire wall and the rim flanges.
The neutral line of the carcass may be empirical-
lye determined in the bead region and an elongation of
the Conner in the direction toward the bead core
passes outside the cross sectional area of the latter.
The beads of the tire relay be disposed on rim
seating surfaces wllicil are located on the radially
outer periphery of the rim ring next to predominantly
radially outwardly extending Rowley flanges.
The neutral line of the carcass, which lay pass
ttlrougll the central point of tile bead cores, may, in
the lower sidewall region, take owe or depart from a
curve shape which follows the diaphragm theory; at the
transition prom this curve shape to the catenary-like
path, the radii of curvature and the pitches of the
two curves are identical. The catenary-like path of
the neutral line of the carcass may be positively
guided by the rim over at most S0~10 of the length of
the catenary curve. In the equation y = a gosh ( pa- Jo
which describes the catenary-lilce path of the neutral
line of the carcass, "arranges from 10 to 40 Imp.
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Description of Preferred Embodiments
Referring now to the drawings in d tail, the
pneumatic vowel tire utilized with the wheel of
Figure 1 essentially comprises rubber or rubber-like
materials. Furthermore, this tire comprises a single-
ply radial carcass 1 which is made of textile film nuts
disposed in a cord ply, yet can also be made of steel
wires. If required, the carcass 1 can, of course,
also comprise several plies. The ends of the carcass
1 are anchored in the beads 2 by being looped around
the pull-resis~an~ bead cores JO Below the tread 4,
and between it and the carcass 1, there is located
a belt S which is pull-resistan~ in the circumferential
direction of the tire, comprises two or more cord
fabric pow, and produces lateral stabilization of the
tire body. .
The beads 2 ox the belted tire are mounted on the
radially inner side of the rim ring 6, which is sup-
ported it the customary manner by a rim well 7. Bead
- 20 seating surfaces of the tire are disposed on rim seat
in surf aces, which in turn are disposed next to rim
flanges 8 which extend radially inwardly and axially
outwardly. Recessed portions 9, which assist in
mounting the tire, adjacent to and axially inwardly
of the rim seating surfaces.
During manufacture of the tire, the carcass 1
-- 6 --
is to be disposed in the tire in such a way that the
path of the neutral line of the carcass, at least in
the lower sidewall region, at the level of the rim
flange, and laterally outwardly -wherefrom, obeys or
confines to the function or equation of a catenary.
With ho wire of Figure 1, the neutral line of the
carcass furthermore also follows the some catenary
in the bead region; this catenary ends approximately
in the middle point of the core cross section.
Figure 2 illustrates the neutral line 10 of the
carcass of the wire of Figure 1. Also shown in Figure
2 is an I, y-coordinate system, with the x axis being
disposed in the axis of rotation of the wheel and
tire, and the y axis being disposed in the central
plane of the wheel The catenary-like path so of the
neutral line 10 of the carcass is in every case less
than the¦greates~ tire width, and is characterized by
the equation
y = a gosh pa b)
where
b a - the distance from the y axis to the
lowest point A of the catenary
a - the distance prom the x axis to the
lowest point A ox the eatenary.
On one side the catenary so ends in the interior
of the bead core 3, and on the other side it ends in
-- 7
the lower sidewall region of the tire. The adjoining
portion of the neutral line 10 of the carcass is
characterized, as far as an equation goes, with the
aid of ye diaphragm err The transition of the
two curve shapes is characterized in thaw a that point
the radii of curvature and the pus of the two
curves are identical.
In the vicinity of the bead cores 3, the ea~enary-
like path of the neutral line of the carcass is positive
lye guided by the shape and orientation of the rim flanges
8. It has been demonstrated that this favorable post-
live guidance should no extend over more than 80% of
the overall length of the catenary-like path so of the
neutral line of the carcass.
In Figure 3, the catenary-like path of the
neutral line of the carcass of Figure 2 is illustrated
in connection with a transformation of coordinates,
with A, and x x + b a, so that in the
x, y-system, there results the generally crown equal on0 for a catenary
y - a Josh a J
For the radius of curvature of this curve, the
following is applicable: _
g - a couch ( - )
a
From this there follows for the least radius of
curvature g at the lowest point ox the curve (x 0):
-- 8 --
glue
p- a
With customary tire sizes or passenger cars,
"a" should range from lo to 40 Imp, with 15 to 30 mm
being preferred.
With thy vehicle wheel of Figure 4, the tine
is provided with a diagonal or biased carcass 11, and
it has no belt. The remaining parts of the vehicle
wheel correspond Jo those of the wheel of Figure 1
with the exception of the disposition of the neutral
line I of the carcass in the bead region. Although
with the vowel wheel of Figure 4 the neutral line
10 of the carcass in the lower sidewall region at to
level of the rim flanges 8 and laterally outwardly
thereof conforms to the equation of a kiter (curve
sky and in the further sidewall region is character-
iced by the diaphragm theory the transition between
the two curves is defined in the same way as was the
case with the wheel of Figure 1), the neutral line
10 of the carcass in the bead region, ire, axially in-
warmly from the level of the rim flanges, was empirical-
lye determined (section ON) and disposed. For compare-
son, in Figure 4 the curve of the catenary so is con-
inured axially inwardly and one can see thaw it passes
oozed the cross-sectional surface of the bead core 3.
In a critical case, the catenary curve could ~angenti-
ally contact the bead cove 3.
Lo
Figure 5 illustrates a vehicle wheel where
the neutral line 10 of the tire carcass conforms to
the equation of a Conner not only in the lower
sidewall region but also in the bead region. A quite
large portion of the d~c~dlng branch of the catenary
Sk is utilized in the bead region, and the lowest point
A is located approximately below the rim flange 8.
So that with this construction hazing the great curve-
lure of the Conner Sky the Kiln flanges 8 and the tire
beads 2 and sidewalls can be disposed in the customary
manner, a spacer 12 is disposed between the tire wall
and the rim Lange 8. The spacer 12 comprises a
sufficiently hard rubber, and is glued or otherwise
fastened to the rim flange 8. The spacer 12 can,
at the same time, serve for passive guidance of the
tire laterally of the rim flange 80 The tire can have
a radial or diagonal carcass.
With the vehicle wheel of Figure 6, the tire
has a radial carcass 1' which is anchored in the beads
2' by being looped around the bead cores 3 ', Thy wire
is mounted radially outwardly on the rim King 6' next
to the rim flanges 8'. A support member 13 serves to
support the tire it a pressure loss result, for example
due to a puncture or a blowout . In this embodiment
also the neutral line 10 of the carcass conforms in
the lower sidewall region end in the bead region to
I
the equation of a catenary, so thaw the vehicle wheel
has the advantages which can be achieved therewith.
In order to better show the path of the catenary, a
set of curves is illustrated in Figure 7. The bottom
curve corresponds to a path which is in confonnity
with the diaphragm theory, while the further curves,
which are shown in dashed fines, represent catenaries
. having various parameters. It can readily be seen
that the tire of Figure 6 has a carcass neutral line
which conforms to the catenary so of Figure 7.
In summary, it is to be emphasized thaw with all
of the described tires it is important that the neutral
line 10 of the carcass be constructed or disposed in
a catenary manner in thy lower sidewall region, where
in driving operation certain movements occur; this
catenary construction can also be provided in the bead
region, although it is not necessary to do so.
If necessary, deviations from the illustrated
examples are possible, allowing other combinations of
the individual elements. Thus, for example, the tire
of Figure 4 can also be provided with a radial carcass,
and the embodiment of Figure 6 could be provided with
a diagonal carcass.
The present invention is, of course, in no
way restricted to the specific disclosure of the
specification and drawings, but also encompasses any
modifications within thy scope of the appended claims.
