CA1221300A

CA1221300A - Vehicle wheel

Info

Publication number: CA1221300A
Application number: CA000458546A
Authority: CA
Inventors: Alfred Duchow; Peter Hahn
Original assignee: Continental Gummi Werke AG
Current assignee: Continental AG
Priority date: 1983-07-11
Filing date: 1984-07-10
Publication date: 1987-05-05
Also published as: GR82320B; ES289094Y; EP0131117A2; ES289094U; BR8403418A; EP0131117A3; KR850001093A; EP0131117B1; DE3465276D1

Abstract

TITLE OF THE INVENTION:
VEHICLE WHEEL
ABSTRACT OF THE DISCLOSURE:
A vehicle wheel having a rigid rim on which is mounted a pneumatic tire which essentially comprises rubber or rubber-like synthetic material. The tire has a single or multi-ply carcass of 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. The tire wall, in the region of the rim flanges, extends approximately horizontally toward the outside. To optimize the neutral line of the carcass, the path of the latter, at least in the lower sidewall region at the level of the rim flange, and laterally outwardly therefrom, conforms to the equation of a catenary.

Description

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 :~2~30~;) 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 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.

I

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 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 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 on 0 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):

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.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A vehicle wheel having a rigid rim in-cluding a rim well and a rim ring with rim seating surfaces as well as rim flange; 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 in-wardly of, said rim flanges; said tire having side-walls, 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 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 thire 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.

2. A vehicle wheel in combination according to claim 1, in which said rim seating surfaces are disposed on the radially inner periphery of said rim ring; and in which said rim flanges extend pre-dominatly radially inwardly.

3. A vehicle wheel in combination according to claim 2, in which said neutral line of said carcass also conforms to said equation of a catenary in the region of said tire beads; and in which said catenary curve ends within the cross-sectional areas of said bead cores.

4. A vehicle wheel in combination according to claim 3, in which said neutral line of said carcass passes through the center of said bead cores.

5. A vehicle wheel in combination according to claim 3, in which the catenary-like path of said neutral line of said carcass is positively guided by said rim over up to 80% of the length of said catenary curve.

6. A vehicle wheel in combination according to claim 3, in which said catenary-like path of said neutral line of said carcass is defines by the x-y coordinated equation y = a cosh , where "a"
ranges from 10 to 40 mm.

7. A vehicle wheel in combination according to claim 2, in which a spacer is disposed between each sidewall and its rim flange.

8. A vehicle wheel in combination according to claim 1, in which said neutral line of said car-cass is empirically determined in said bead regions;
and in which an elongation of said catenary curve, in the direction toward said bead cores, passes by the cross-setional area of the latter.

9. A vehicle wheel in combination according to claim 1, in which said rim seating surfaces are disposed on the radially outer periphery of said rim ring; and in which said rim flanges extend predomi-nantly radially outwardly.