CA1081592A - Pneumatic tire and rim therefor - Google Patents
Pneumatic tire and rim thereforInfo
- Publication number
- CA1081592A CA1081592A CA286,699A CA286699A CA1081592A CA 1081592 A CA1081592 A CA 1081592A CA 286699 A CA286699 A CA 286699A CA 1081592 A CA1081592 A CA 1081592A
- Authority
- CA
- Canada
- Prior art keywords
- tire
- rim
- wall
- tread
- lateral
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
- B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
- B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C15/00—Tyre beads, e.g. ply turn-up or overlap
- B60C15/02—Seating or securing beads on rims
- B60C15/0233—Securing tyres without beads; Securing closed torus or tubular tyres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C3/00—Tyres characterised by the transverse section
- B60C3/02—Closed, e.g. toroidal, tyres
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
PNEUMATIC TIRE AND RIM THEREFOR
ABSTRACT OF THE DISCLOSURE
A tube tire with radial side wall reinforcing and a peripheral tread belt has breakers in the tread wall to provide lateral stiffness so that in a rolling turn substantial lateral force is developed in the tread. The rim wall of the tire is securely fixed to the wheel rim so that the lateral force from the tread wall is efficiently transferred to the vehicle.
ABSTRACT OF THE DISCLOSURE
A tube tire with radial side wall reinforcing and a peripheral tread belt has breakers in the tread wall to provide lateral stiffness so that in a rolling turn substantial lateral force is developed in the tread. The rim wall of the tire is securely fixed to the wheel rim so that the lateral force from the tread wall is efficiently transferred to the vehicle.
Description
S~
The load carrying capacity of a pneumatic tire ls a function primarily of the width of the tread and the internal tire pressure. The tire diameter is also a factor as it affects the area of tread surface in contact with the road, but diameter is of lesser significance than tread width. Moreover, practical tire diameters are limited by the size of the vehicles with which the tire is used. For a given load, a tire within a range o widths and pressures can be selected. As the tire width is increased more material-is re~uired and the cost of the tire and of the rim on which it is mounted increase. It is desirable ~or economic reasons to use a narrow tire and~a high pressure.
Uowever, the "ride cuality" of the tire must also be considered.
It is a subJective measure of the performance of the vehicle and to some extent individuals will differ in their conclusion as -to what is a "good" ride. The ride quality is affected both by tire construction and by the operating pressure. No satisfactory ob~jective measure has been established. Generally, however, a maximum pressure of the order of 20 to 30 psi is utilized with open carcass tires on a passenger vehicl.e. A higher pressure causes a harsh, uncomfortable ride. Within this pressure range and the desired tire diameter, a width is selected -to support the anticipated load.
Grawey U. S. patent 3,606,921 issued September 21, 1971 discloses a pneumatic tube tire which has, among other features, a capacity of providing a soft, comfortable ride with little noticeable difference in quality over a pressure range from 20 psi to as high as 50 or 60 psi. The Grawey tube tire selected for a given load may be much smaller than a beaded, open carcass tire for the same load, resulting in a material cost reduction and a weight saving. The tube tire includes a ' ~
... . . ~ . . _ . ..
z toroidal. elastomer carcass with an outer tread wall, an inner rim wall and a pair of side ~alls interconnecting the tread and rim walls. The carcass is reinforced with a continuous inextensible filament wound in generally radial planes. A tread belt has ine~tensible reinforcing ~,enerally parallel with the Rlane of the tire. It is my present theory that the independence of ride nuality from tire pressure is due in part to the side wall construction with uniform radial reinforcing elements, by virtue of which the incremental side wall deflection at -the rim and tread is symmetrical as the load on the tire changes. The tire has a higher torsional spring rate than comparable tires of open carcass construction and this may also contribute to ~he high quality of the ride.
In contrast to the subJective nature of the ride quality of the tire, the characteristlcs of a tire which contribute to vehicle directional control and dynamic stability in turns have been analyzed objectively. The General Motors Co~pany has developed Tire Performance Criteria (TPC) which include force and moment characteristics that provide a measure of the directional control capability of a vehicle with which the tire is used. The criteria are described in a publica-tion entitled "General Motors Tire Performance Criteria (TPC) Specification System"; and the force and moment characteristics are defined at pages 74-77. The principal tire characteristics `~5 affecting the linear directional control performance of the vehicle is the cornering coefficient, which is defined as the lateral force produced at a one degree slip angle and 100 percent of the rated load, divided by the rated load i.
._ _ _ . .. . , . . , . . . ., .. . _ _ ,.. , ____ _ _, _ _ .
' The tires initially made in accordance with the Grawey patent were typically 64 or 88 inches in diameter and were used with off-road earthmoving vehicles. The performance criteria for automobile tires are not of great significance for such vehicles. A tire having the same construction but reduced in size to a diameter of 27 inches for use on an automobile was found to have good ride quality and long life but to be`deficient in directional control factors important in the design and operation of passenger vehicles. The cornering coefficient was too low for satisfactory use on a passenger vehicle in road service.
This invention is concerned with improvements of the tire shown in the above-referenced ~rawey patent to achieve force and moment characteristics which meet or exceed the General Motors Tire Performance Criteria without adversely affecting the desired characteristics of the tire of the Grawey patent, including a low rolling resistance, long life and soft ride at high inflation pressure.
In a rolling turn the lateral force which provides the cornering coefficient is developed in that portion of the tire tread which engages the road surface (the "footprint" of the tire) and is transmitted from the tread through the side wall to the rim engaging portion of the tire, and thus to the wheel and the vehicle where it is effective to change the direction o vehicle movement.
A principal object of the invention is to stiffen the tread of the tire with respect to lateral forces and to transmit efficiently to the wheel rim the lateral force developed in the ` tread.
~0~3~S9Z
According to the invention a radially reinforced pneumatic tire and rim assembly therefor, with a ratio of lateral force to load in a rolling turn sufficient to establish a cornering coefficient satisfactory for vehicle road use, comprises a pneumatic tire having an elastomer carcass with a peripheral inextensible annular tread wall, a pair of annular rim wall portions and a pair of opposed annular side walls each joining a lateral edge of the tread wall with a lateral edge of the respective rim wall portion, a pair of roll restraining hoops each connected to one of the rim wall portions, radial reinforcing in the side walls, the rim wall portions, and the tread wall, the construction of the tire being such that incremental deformation of the side walls at their ~unctures with the tread wall and rim wall portions is substantially symmetrical under load in the plane of the tire; a rim having a pair of annular surfaces on which the tire rim wall portions are received; means in said tire tread wall for imparting lateral stiffness thereto to resist bending of the footprint of the tire so that a substantial lateral force is developed in the tread wall in a rolling turn;
and means for securing the tire rim wall portions to the annular surfaces of the rim to restrain movement there-between in a direction axial of the tire and rim so that the lateral force developed in the tire tread wall and transmitted through the side walls to the rim wall portions is transmitted from the rim wall portions to the rim, said securing means including a pair of radially outwardly extending annular rim surfaces provided on the rim each being positioned in motion restraining relation to the respective roll restraining hoop, preventing lateral ~ -5-. .
- ~o~s~z movement thereof relative to the rim as a result of lateral force developed in a rolling turn, the radially outwardly extending annular rim surfaces and the roll restraining hoops being spaced axially inwardly of the juncture of the respective side wall and rim wall portion.
The invention provides stiffness in the tread of the tire with respect to lateral forces and enables the force to be transmitted efficiently to the wheel rim.
The tread wall of the tire may be laterally stiffened by a pair of complementary bias reinforcing strips which have substantial lateral stiffness.
The tire may include annular bodies between the lateral edges of the tread wall and/or each hoop and the respective side walls, ~nhancing the transfer of force through the tire in a rolling turn between the roll restrain-ing hoops, to prevent lateral inward movement of the hoops with respect to the surface of the wheel rim.
Further features and advantages will readily be apparent from the following specification and from the drawings, in which:
Figure 1 is a broken perspective of a prior art tire illustrated in said Grawey U. S. Patent 3,606,921i Figure 2 is a diagram of forces on a tire in a rolling turn;
Figures 3a, 3b and 3c are diagrams illustrating a series of tire footprints in idealized form;
Figure 4 is a cross-section of a tire embodying the invention;
Figure 5 is a broken perspective of the tire of Figure 4; and -5a-~. I
lOB~S92 Figure 6 is a diagrammatic illustration of a test useful in comparing materials used in stiffening the tread of the tire.
A prior art tube tire will be considered briefly to illustrate the problems solved by the present invention.
Figure 1 is a broken perspective view of the tire of Figure 7 of Grawey U. S. patent 3,606,921. The elastomer carcass 20 has a tread wall 21, a rim wall 22 and side walls 23, 24. The carcass is reinforced by a single layer wrapped filament 25 with turns lying substantially in radial planes. A unitary circumferential tread 27 surrounds the carcass and includes reinforcing elements 28 which are arranged in planes generally parallel with the plane of the tread so that the tire is effectively inextensible peripherally. Reinforcing elements 25, 28 may, for example, be steel wires. Rim wall 22 has at its outer edges a pair of roll restraining hoops 29, 30 prefer-ably wound of steel wire.
The rim wall 22 has a centrally located radial rib 31 received in a centering recess 32 between the split sections 33, 34 of the rim. Further details of the tire construction and its manufacture may be found in the above-referenced Grawey patent. The tire of Figure 1 has many desirable features including a soft ride characteristic over a wide range of inflation pressures, long life and a low rolling resistance which contributes to low fuel con-sumption. The prior art tire, however, has shortcomings which affect its suitability for a road-service passenger vehicle as an automobile or truck.
59~
A consideration of the tire force and moment diagram of Figure 2 will aid in the following discussion. This diagram is adapted from the conventions recommended by the Society of Automotive Engineers. The tire and wheel 38 are illustrated on a road plane 39. The longitudinal plane of the wheel 40 corresponds with the direction of wheel heading, arrow 41. The direction of wheel travel, arrow 42, is displaced from the wheel direction by a slip angle ~. The displacement between the wheel heading and wheel travel results in establishment of a lateral force indicated by arrow 44 in the plane 45 through the center of the wheel and at right angles to the wheel plane 40. For the positive slip angle shown, the lateral force will be in the ne~ative direction. The load on the wheel is represented by a normal force, arrow 46. An aligning torque, arrow 47, tends to rotate the wheel to align the wheel heading with the wheel travel.
In a moving vehicle it is the lateral force 44 which causes a change in vehicle direction when the steering wheels are turned. The relationship of the lateral force to the wheel ~0 load and slip angle affect the handling characteristics of the vehicle. If the lateral force is too great, the vehicle will respond violently and be difficult to control. If the la-teral force is small, vehicle response is sluggish. The structure of the tire and the interconnection of the tire and the wheel are ~5 major factors in establishing the lateral force 44.
In a turn a force is generated by interaction between the tire tread and the road surface. The dynamics of the genera-tion of the force in the tread are complex. A simplified qualitative discussion is sufficient for an explanation of the lnvention. The portion of the periphery of the tire which en-gages the road surface, sometimes referred to as the footprint ~611i3~L5~Z
of the tire, is illustrated diagrammatically in Figure 3a for a tire traveling in the direction of its heading. l`he longitu-dinal axis 5-1 of the footprint 50 is a straight line. When wheel heading and direction of travel differ, the footprint is deformed as shown at 52 and 53, Figures 3b and 3c, respecti.vely. The ex-tent of the deformation, which mày be measured by the angle ~
between the segments of longitudinal axes ~l, 55, is determined principally by the slip angle a and the resistance of the tread to lateral deformation. If the tread has little lateral stiff-ness, the footprint deformation is greater, Figure 3b, than if ' the tire is stif, Figure 3c.
The General Motors Tire Performance Criteria discussed above identifies the ability of a tire to generate a lateral force 4~ in a turn by a cornering coefficient, defined as the lateral force which is generated at a 1 slip an~,le and rated tire load, divided by the rated load.
The first tires built in accordance with the above-referenced U.S. patent 3,606,921 in a size for use on passenger vehicles for road operation (sometimes referred to herein as "automotive tires") were found to have a cornering coefficient insufficient for passenger vehicles. ~e believe that this low cornering coefficient results from the fact that the peripheral tread with reinforcing. elements 28 parallel with the plane of the tire has little resistance to lateral deformation. The footprint deforms in a turn as illustrated in ~igure 3b.
Two principal changes have been made to overcome this problem. First, the tread is stiffened laterally. This reduces deformation of the footprint, Fi~ure 3c, and results in the gen-eration within the tread of-a higher lateral force. Second, ~he tire is interconnected with the wheel rim to minimize relative ~movement so that the lateral force developed in the tire tread ...... _ _.. _ . . __ _ . . _ __ .__ . _ . .. .
. .
55~Z
is efficiently transferred from the tire to the wheel.
The lateral stiffness of the tread section of the tire is preferably increased by incorporating in the tread wall a layer or layers of material which resist the bending that occurs in the footprint during a rolling turn.
A construction which has been found satisfactory is illustrated in Figures 4 and 5. In this construction, two radially spaced elastomer strips with reinforcing elements arranged at complementary bias angles with respect to the plane of the tire underlie the inextensible peripheral reinforcing belt. More particularly, lateral reinforcing breaker strips 63, 64 underlie and are of greater width than peripheral belt 65 and enhance the lateral stiffness of the tread. The strip 64 is wider than the strip 63. Further details of these reinforcing strips are discussed below.
; It is not enough that the lateral force be develop-ed in the tire tread. The force must be efficiently trans-mitted through the side wall to the rim wall and from the ~0 rim wall to the rim of the wheel. The interconnection of the tire rim wall and the wheel rim will be considered next. A lateral force applied to the tread wall of the Grawey tube tire shifts the tread wall sideways and increases the force tending to move the roll restraining hoop on the outside of the turn inwardly on the wheel rim. Any ; movement of the hoop results in a shear force in the rim wall that dissipates some of the lateral force, reducing the force which is effective to turn the vehicle.
_g_ S9;2 Figures 4 and 5 illustrate a construction in which the rim surface 76 on which the rim wall 77 of the tire is seated is provided with a centrally located radial step 78 which extends outwardly and has a lateral dimension corresponding with the spacing between the inner surfaces 79, 80 of roll restraining hoops 81, 82.
Again, the interlocking connection between the tire rim wall and the mounting surface of the rim restricts relative movement of the tire and rim for efficient force .
transfer.
The rim surface 76 may be a transversely split ring with an expander and mounting member 84, both describ-ed in moxe detail in U. S. Patent No. 3,998,258 issued December 21, 1976 to Grawey and Groezinger. Tire rim wall 77 has a generally straight inner surface in unstressed condition. Expansion of annular rim surface 76 against the tire causes the rim step 78 to deform the tire rim wall outwardly between the roll restraining hoops 81, 82.
The dynamic mechanical action which occurs at the junctures of the side walls with the tread wall and the rim wall during a rolling turn, transferring the lateral force from the tread wall to the rim wall is complex and not fully understood. It is believed that the principal action takes place in the vicinity of the lateral edges of the inextensible peripheral reinforcing belt 65 and at the axially outer surfaces 75 of the roll restraining hoops 81, 82. The force transfer from the tread wall to the side walls and from the side walls to the rim wall is enhanced by restricting lateral deformation of the side walls in these areas. More specifically, with reference -la-~(~8~S~
to Figure 4, the elastomeric body of the tire is thickened at shoulders 88 in the sidewall regions adjoining the edges of the tread wall and elastomeric fillers 89 are provided between the axially outer surfaces 75 of roll restraining hoops 81, 82 and the inner surface of the side walls. The shoulders and fillers 88, 89 are formed by annular bodies of elastomer incorporated in the composite tire structure prior to vulcanization.
Automotive tires are made in many different sizes to accommodate different loads, with a diameter and width ~hich complement the styling of the vehicle. The physical dimensions and other tire characteristics, including the Tire Performance Criteria, are related to the tire size. Some of the dimensions and component characteristics of the tube tires of Figures 4, 5 corresponding to an open carcass beaded tire size HR78-15 will be given by way of examples. It will be understood that different combinations of materials and dimensions may be used in constructing other forms of this tire and other sizes of tire.
The HR78-15 at a maximum pressure of 32 psi is rated for a load of 1770 pounds. The General Motors Tire Performance Criteria establishes a nominal cornering coefficient of 0.160 for this tire. Other tires for which General Motors has issued specifications have nominal cornering coefficients from 0.150 to 0.195. The HR78-15 on a 6.00 inch rim has a section width of 8.~5 inches and a height from bead to tread of 6.6 inches.
`
.
~08~S9~
A lighter weight tire is illustrated in Figures 4 and 5. The section ~idth is 8 inches but the tire has a side wall thickness of 0.23 inches. The radius of the outer side wall surface is 2.6 inches.
Tread width is 5~1 inches. The radial side ~all reinforcement 96 is 3 x .010 steel cable with 7 filaments per inch. Lateral reinforcing sheets 63, 64 are 4.60 and 4.90 inches wide, respectively, and each has 4 x 4 x .007 steel cable reinforcing with 14 filaments 97 per inch. Inextensible belt 65 is 4 inches wide and reinforced with 5 x .010 inch steel cable with 16 ~ilaments 98 per inch. Roll restraining hoops 81, 82 are of 6 x 5 x .037 steel ~-re. Rim step 78 has a radial dimension of 0.10 inch and a width of 1.95 inches.
Suitable elastomer compounds fnr the tire are identified by code number in Table A. The principal constituents and physical characteristics of the elastomer compounds are given in Table B.
... . . .. . . .. . .... .
s9~
TABLE A
. Tire Part Tire Figures 4,5 Tube Stock t.inside the T208 radial reinforcing) Bond Stock B320 .
;;` Sidewall C657 Tread C657 Hoop Filler V904 10BlS5~2 .. . . . ...
~ ~ r~~rl rlrl ~rl h ~ \\ \
o Q) O~rl R.4 ~ Q
E-l h 1 :~r~ 1 r~ ~I r-l cn o o Ou~ r~
t~ ~ r-l r-l O
~rl ~ o~o~o o\Oo\O o\O o\O
~t) O O O ~) O O
O O O 1~ 0 O
U O r-l(Y) r~ ) r-l r~ rl U~
r~ U~
Ul rl OO ~ N CO O
O U~ InO ~ ~ r-l O
) ot~
r-l~ r-l r l U~
O
~rl ~Oo\O o\O o\O d~ o\
~ OU~ OO O O
t~ 111 ~O O r l ~ O
~ l~~ r~ r-l 0~ .' a: I ~ ~
~ I~rl ~rl O O O O ~ O
1~ I U~ O O Ir) Is~ ~D O
m l~ ~ O ,~
I E~
_ ::
~ s, U~ ~
a~ ~ a) .
U~
O O L~ Lr) Ln ul CO ,: ' s~ .
Q
a) ~
~ ~ ~ ~ ~ ~Q
O Q a~ .~ rl Q I O
~rl S~ rl ,~ r~
o ~1 ~ ~ ~ ~ ~ u a U~ Q Q r~ Ul r~
O ~ r~ rl ~ p~ 0 O ,~,~ ~ r~ ~ 0 3 C ) ~ O Q h O t~
z ~ ~o m ~ z o\ o\ O o\ ~ r~
~ ~ o o s~
z z a~,~ m ~ m ~ ~ o 1~ co Lt~ ~r O O ~ L~ O r~ O
~ ~ ~ ~ C~
o m m V E~
o - . ,.,, ., , -The tire of Figures 4 and 5 has a cornering coefficient of .159. The tires can be operated at sub-stantially higher pressures than 30 psi with good ride characteristics. The cornering coefficient increases with inflation pressure. Accordingly, the tire can accommodate a significantly greater load than the HR78-15 tire. Conversely, a smaller tire incorporating the invention could be selected for service with a load capability of the HR78-15.
The open carcass HR78-15 tire weighs approxi-mately 32 pounds. The comparable tire of Figures 4 and 5 weighs 25 pounds.
The almost unlimited selection of elastomer materials and reinforcing available for the tire tread wall enables fabrication of tires of various sizes with a desired cornering coefficient. However, it is both expensive and time consuming to build and test a complete tire. We have determined that samples of tread material may be tested in simple beam deflection, providing information regarding stiffness which correlates predict-ably with the cornering coefficient of the tire using the material in the tread. This greatly simplifies the analysis of tread material and the design of tires. Figure 6 illustrates a section of tread material prepared for a beam deflection test. The dimension 115 of the sample 116 corresponds with the peripheral dimension of the tire tread. Dimension 117 corresponds with the transverse dimension of the tread. Three holes 118, 119 and 120 are spaced along the axis of the sample 116 parallel with ., , .. . ~, .,:.. ~ ... . .
~0~3~5~
dimension 115. The specimen is suspended from holes 118 and 120 and a deflecting force is applied to hole 119.
The deflection of the specimen is a measure of its resistance to lateral deformation.
The incremental deflection of the side walls of the tire is related to its multipressure, good ride performance. AS the tire is loaded, the incremental deflections at the junctures of the side walls with the rim and at the junctures of the side walls with the tread wall are uniform. This is to be contrasted with a conventional open carcass, beaded tire where the side wall is stiff in the area of the beads and the principal deflection occurs at the side wall-rim wall juncture.
So long as the tire side wall6 have this capacity for symmetric incremental deflection at the tread wall and rim wall, the multipressure, soft ride and the advantages of the invention in establishing the desired cornering coefficient are achieved. These side wall characteristics do not require the tube tire construction on a core as described in the Grawey patent. While this construction is desirable because it provides tire uniformity and lower cost, similar performance can be achieved with a crown overlap construction if the overlap is buried in the rim wall which is not subject to flexure or even in the tread wall where flexure is minimized. Moreover, it is not necessary that the side wall reinforcement be precisely in radial planes. A deviation of up to 10 is tolerable.
~o~s9%
It is preferable that the tread have the two bias reinforcing layers inside the inextensible 0 belt to eliminate the effect of the bias reinforcing on steer-ing. However, where the bias layers have sufficient resistance to peripheral expansion, as permitting a circumferential expansion of no more than 5%, the 0 belt may be omitted.
There are other characteristics of the tire which contribute to the cornering coefficient but to a lesser extent than the lateral tread reinforcement tire to rim connection and side wall fillers.
The tread width and elasticity of the tread material affect tread stiffness. The cornering coefficient is higher for a wider tread or stiffer material. However, excessive heat is generated in a stiff material and this is detrimental to tire life. The angle between the edge of the tread and the side wall, sometimes described as the tread shoulder angle, may vary substantially. The cornering coefficient is higher for a square relationship ~ than for a smaller angle ~2 .
The tube tires illustrated in Figures 4 and 5, may be manufactured with the procedures described in Grawey 3,776,792, a division of 3,606,921.
While preferred embodiments of the invention have herein been illustrated and described, this has been done by way of illustration and not limitation, and the invention should not be limited except as required by the scope of the appended claims.
s~z The tube tires illustrated in Figures 4, 5, 6 and 7 may be manufactured with the procedures described in Grawey 3,776,792, a division of 3,606,921.
While preferred embodiments of the invention have herein been illustrated and described, this has been done by way o illustration and not limitation, and the invention should not be limite~ except as required by the scope of the appended claims.
.. .. . . ... ...
The load carrying capacity of a pneumatic tire ls a function primarily of the width of the tread and the internal tire pressure. The tire diameter is also a factor as it affects the area of tread surface in contact with the road, but diameter is of lesser significance than tread width. Moreover, practical tire diameters are limited by the size of the vehicles with which the tire is used. For a given load, a tire within a range o widths and pressures can be selected. As the tire width is increased more material-is re~uired and the cost of the tire and of the rim on which it is mounted increase. It is desirable ~or economic reasons to use a narrow tire and~a high pressure.
Uowever, the "ride cuality" of the tire must also be considered.
It is a subJective measure of the performance of the vehicle and to some extent individuals will differ in their conclusion as -to what is a "good" ride. The ride quality is affected both by tire construction and by the operating pressure. No satisfactory ob~jective measure has been established. Generally, however, a maximum pressure of the order of 20 to 30 psi is utilized with open carcass tires on a passenger vehicl.e. A higher pressure causes a harsh, uncomfortable ride. Within this pressure range and the desired tire diameter, a width is selected -to support the anticipated load.
Grawey U. S. patent 3,606,921 issued September 21, 1971 discloses a pneumatic tube tire which has, among other features, a capacity of providing a soft, comfortable ride with little noticeable difference in quality over a pressure range from 20 psi to as high as 50 or 60 psi. The Grawey tube tire selected for a given load may be much smaller than a beaded, open carcass tire for the same load, resulting in a material cost reduction and a weight saving. The tube tire includes a ' ~
... . . ~ . . _ . ..
z toroidal. elastomer carcass with an outer tread wall, an inner rim wall and a pair of side ~alls interconnecting the tread and rim walls. The carcass is reinforced with a continuous inextensible filament wound in generally radial planes. A tread belt has ine~tensible reinforcing ~,enerally parallel with the Rlane of the tire. It is my present theory that the independence of ride nuality from tire pressure is due in part to the side wall construction with uniform radial reinforcing elements, by virtue of which the incremental side wall deflection at -the rim and tread is symmetrical as the load on the tire changes. The tire has a higher torsional spring rate than comparable tires of open carcass construction and this may also contribute to ~he high quality of the ride.
In contrast to the subJective nature of the ride quality of the tire, the characteristlcs of a tire which contribute to vehicle directional control and dynamic stability in turns have been analyzed objectively. The General Motors Co~pany has developed Tire Performance Criteria (TPC) which include force and moment characteristics that provide a measure of the directional control capability of a vehicle with which the tire is used. The criteria are described in a publica-tion entitled "General Motors Tire Performance Criteria (TPC) Specification System"; and the force and moment characteristics are defined at pages 74-77. The principal tire characteristics `~5 affecting the linear directional control performance of the vehicle is the cornering coefficient, which is defined as the lateral force produced at a one degree slip angle and 100 percent of the rated load, divided by the rated load i.
._ _ _ . .. . , . . , . . . ., .. . _ _ ,.. , ____ _ _, _ _ .
' The tires initially made in accordance with the Grawey patent were typically 64 or 88 inches in diameter and were used with off-road earthmoving vehicles. The performance criteria for automobile tires are not of great significance for such vehicles. A tire having the same construction but reduced in size to a diameter of 27 inches for use on an automobile was found to have good ride quality and long life but to be`deficient in directional control factors important in the design and operation of passenger vehicles. The cornering coefficient was too low for satisfactory use on a passenger vehicle in road service.
This invention is concerned with improvements of the tire shown in the above-referenced ~rawey patent to achieve force and moment characteristics which meet or exceed the General Motors Tire Performance Criteria without adversely affecting the desired characteristics of the tire of the Grawey patent, including a low rolling resistance, long life and soft ride at high inflation pressure.
In a rolling turn the lateral force which provides the cornering coefficient is developed in that portion of the tire tread which engages the road surface (the "footprint" of the tire) and is transmitted from the tread through the side wall to the rim engaging portion of the tire, and thus to the wheel and the vehicle where it is effective to change the direction o vehicle movement.
A principal object of the invention is to stiffen the tread of the tire with respect to lateral forces and to transmit efficiently to the wheel rim the lateral force developed in the ` tread.
~0~3~S9Z
According to the invention a radially reinforced pneumatic tire and rim assembly therefor, with a ratio of lateral force to load in a rolling turn sufficient to establish a cornering coefficient satisfactory for vehicle road use, comprises a pneumatic tire having an elastomer carcass with a peripheral inextensible annular tread wall, a pair of annular rim wall portions and a pair of opposed annular side walls each joining a lateral edge of the tread wall with a lateral edge of the respective rim wall portion, a pair of roll restraining hoops each connected to one of the rim wall portions, radial reinforcing in the side walls, the rim wall portions, and the tread wall, the construction of the tire being such that incremental deformation of the side walls at their ~unctures with the tread wall and rim wall portions is substantially symmetrical under load in the plane of the tire; a rim having a pair of annular surfaces on which the tire rim wall portions are received; means in said tire tread wall for imparting lateral stiffness thereto to resist bending of the footprint of the tire so that a substantial lateral force is developed in the tread wall in a rolling turn;
and means for securing the tire rim wall portions to the annular surfaces of the rim to restrain movement there-between in a direction axial of the tire and rim so that the lateral force developed in the tire tread wall and transmitted through the side walls to the rim wall portions is transmitted from the rim wall portions to the rim, said securing means including a pair of radially outwardly extending annular rim surfaces provided on the rim each being positioned in motion restraining relation to the respective roll restraining hoop, preventing lateral ~ -5-. .
- ~o~s~z movement thereof relative to the rim as a result of lateral force developed in a rolling turn, the radially outwardly extending annular rim surfaces and the roll restraining hoops being spaced axially inwardly of the juncture of the respective side wall and rim wall portion.
The invention provides stiffness in the tread of the tire with respect to lateral forces and enables the force to be transmitted efficiently to the wheel rim.
The tread wall of the tire may be laterally stiffened by a pair of complementary bias reinforcing strips which have substantial lateral stiffness.
The tire may include annular bodies between the lateral edges of the tread wall and/or each hoop and the respective side walls, ~nhancing the transfer of force through the tire in a rolling turn between the roll restrain-ing hoops, to prevent lateral inward movement of the hoops with respect to the surface of the wheel rim.
Further features and advantages will readily be apparent from the following specification and from the drawings, in which:
Figure 1 is a broken perspective of a prior art tire illustrated in said Grawey U. S. Patent 3,606,921i Figure 2 is a diagram of forces on a tire in a rolling turn;
Figures 3a, 3b and 3c are diagrams illustrating a series of tire footprints in idealized form;
Figure 4 is a cross-section of a tire embodying the invention;
Figure 5 is a broken perspective of the tire of Figure 4; and -5a-~. I
lOB~S92 Figure 6 is a diagrammatic illustration of a test useful in comparing materials used in stiffening the tread of the tire.
A prior art tube tire will be considered briefly to illustrate the problems solved by the present invention.
Figure 1 is a broken perspective view of the tire of Figure 7 of Grawey U. S. patent 3,606,921. The elastomer carcass 20 has a tread wall 21, a rim wall 22 and side walls 23, 24. The carcass is reinforced by a single layer wrapped filament 25 with turns lying substantially in radial planes. A unitary circumferential tread 27 surrounds the carcass and includes reinforcing elements 28 which are arranged in planes generally parallel with the plane of the tread so that the tire is effectively inextensible peripherally. Reinforcing elements 25, 28 may, for example, be steel wires. Rim wall 22 has at its outer edges a pair of roll restraining hoops 29, 30 prefer-ably wound of steel wire.
The rim wall 22 has a centrally located radial rib 31 received in a centering recess 32 between the split sections 33, 34 of the rim. Further details of the tire construction and its manufacture may be found in the above-referenced Grawey patent. The tire of Figure 1 has many desirable features including a soft ride characteristic over a wide range of inflation pressures, long life and a low rolling resistance which contributes to low fuel con-sumption. The prior art tire, however, has shortcomings which affect its suitability for a road-service passenger vehicle as an automobile or truck.
59~
A consideration of the tire force and moment diagram of Figure 2 will aid in the following discussion. This diagram is adapted from the conventions recommended by the Society of Automotive Engineers. The tire and wheel 38 are illustrated on a road plane 39. The longitudinal plane of the wheel 40 corresponds with the direction of wheel heading, arrow 41. The direction of wheel travel, arrow 42, is displaced from the wheel direction by a slip angle ~. The displacement between the wheel heading and wheel travel results in establishment of a lateral force indicated by arrow 44 in the plane 45 through the center of the wheel and at right angles to the wheel plane 40. For the positive slip angle shown, the lateral force will be in the ne~ative direction. The load on the wheel is represented by a normal force, arrow 46. An aligning torque, arrow 47, tends to rotate the wheel to align the wheel heading with the wheel travel.
In a moving vehicle it is the lateral force 44 which causes a change in vehicle direction when the steering wheels are turned. The relationship of the lateral force to the wheel ~0 load and slip angle affect the handling characteristics of the vehicle. If the lateral force is too great, the vehicle will respond violently and be difficult to control. If the la-teral force is small, vehicle response is sluggish. The structure of the tire and the interconnection of the tire and the wheel are ~5 major factors in establishing the lateral force 44.
In a turn a force is generated by interaction between the tire tread and the road surface. The dynamics of the genera-tion of the force in the tread are complex. A simplified qualitative discussion is sufficient for an explanation of the lnvention. The portion of the periphery of the tire which en-gages the road surface, sometimes referred to as the footprint ~611i3~L5~Z
of the tire, is illustrated diagrammatically in Figure 3a for a tire traveling in the direction of its heading. l`he longitu-dinal axis 5-1 of the footprint 50 is a straight line. When wheel heading and direction of travel differ, the footprint is deformed as shown at 52 and 53, Figures 3b and 3c, respecti.vely. The ex-tent of the deformation, which mày be measured by the angle ~
between the segments of longitudinal axes ~l, 55, is determined principally by the slip angle a and the resistance of the tread to lateral deformation. If the tread has little lateral stiff-ness, the footprint deformation is greater, Figure 3b, than if ' the tire is stif, Figure 3c.
The General Motors Tire Performance Criteria discussed above identifies the ability of a tire to generate a lateral force 4~ in a turn by a cornering coefficient, defined as the lateral force which is generated at a 1 slip an~,le and rated tire load, divided by the rated load.
The first tires built in accordance with the above-referenced U.S. patent 3,606,921 in a size for use on passenger vehicles for road operation (sometimes referred to herein as "automotive tires") were found to have a cornering coefficient insufficient for passenger vehicles. ~e believe that this low cornering coefficient results from the fact that the peripheral tread with reinforcing. elements 28 parallel with the plane of the tire has little resistance to lateral deformation. The footprint deforms in a turn as illustrated in ~igure 3b.
Two principal changes have been made to overcome this problem. First, the tread is stiffened laterally. This reduces deformation of the footprint, Fi~ure 3c, and results in the gen-eration within the tread of-a higher lateral force. Second, ~he tire is interconnected with the wheel rim to minimize relative ~movement so that the lateral force developed in the tire tread ...... _ _.. _ . . __ _ . . _ __ .__ . _ . .. .
. .
55~Z
is efficiently transferred from the tire to the wheel.
The lateral stiffness of the tread section of the tire is preferably increased by incorporating in the tread wall a layer or layers of material which resist the bending that occurs in the footprint during a rolling turn.
A construction which has been found satisfactory is illustrated in Figures 4 and 5. In this construction, two radially spaced elastomer strips with reinforcing elements arranged at complementary bias angles with respect to the plane of the tire underlie the inextensible peripheral reinforcing belt. More particularly, lateral reinforcing breaker strips 63, 64 underlie and are of greater width than peripheral belt 65 and enhance the lateral stiffness of the tread. The strip 64 is wider than the strip 63. Further details of these reinforcing strips are discussed below.
; It is not enough that the lateral force be develop-ed in the tire tread. The force must be efficiently trans-mitted through the side wall to the rim wall and from the ~0 rim wall to the rim of the wheel. The interconnection of the tire rim wall and the wheel rim will be considered next. A lateral force applied to the tread wall of the Grawey tube tire shifts the tread wall sideways and increases the force tending to move the roll restraining hoop on the outside of the turn inwardly on the wheel rim. Any ; movement of the hoop results in a shear force in the rim wall that dissipates some of the lateral force, reducing the force which is effective to turn the vehicle.
_g_ S9;2 Figures 4 and 5 illustrate a construction in which the rim surface 76 on which the rim wall 77 of the tire is seated is provided with a centrally located radial step 78 which extends outwardly and has a lateral dimension corresponding with the spacing between the inner surfaces 79, 80 of roll restraining hoops 81, 82.
Again, the interlocking connection between the tire rim wall and the mounting surface of the rim restricts relative movement of the tire and rim for efficient force .
transfer.
The rim surface 76 may be a transversely split ring with an expander and mounting member 84, both describ-ed in moxe detail in U. S. Patent No. 3,998,258 issued December 21, 1976 to Grawey and Groezinger. Tire rim wall 77 has a generally straight inner surface in unstressed condition. Expansion of annular rim surface 76 against the tire causes the rim step 78 to deform the tire rim wall outwardly between the roll restraining hoops 81, 82.
The dynamic mechanical action which occurs at the junctures of the side walls with the tread wall and the rim wall during a rolling turn, transferring the lateral force from the tread wall to the rim wall is complex and not fully understood. It is believed that the principal action takes place in the vicinity of the lateral edges of the inextensible peripheral reinforcing belt 65 and at the axially outer surfaces 75 of the roll restraining hoops 81, 82. The force transfer from the tread wall to the side walls and from the side walls to the rim wall is enhanced by restricting lateral deformation of the side walls in these areas. More specifically, with reference -la-~(~8~S~
to Figure 4, the elastomeric body of the tire is thickened at shoulders 88 in the sidewall regions adjoining the edges of the tread wall and elastomeric fillers 89 are provided between the axially outer surfaces 75 of roll restraining hoops 81, 82 and the inner surface of the side walls. The shoulders and fillers 88, 89 are formed by annular bodies of elastomer incorporated in the composite tire structure prior to vulcanization.
Automotive tires are made in many different sizes to accommodate different loads, with a diameter and width ~hich complement the styling of the vehicle. The physical dimensions and other tire characteristics, including the Tire Performance Criteria, are related to the tire size. Some of the dimensions and component characteristics of the tube tires of Figures 4, 5 corresponding to an open carcass beaded tire size HR78-15 will be given by way of examples. It will be understood that different combinations of materials and dimensions may be used in constructing other forms of this tire and other sizes of tire.
The HR78-15 at a maximum pressure of 32 psi is rated for a load of 1770 pounds. The General Motors Tire Performance Criteria establishes a nominal cornering coefficient of 0.160 for this tire. Other tires for which General Motors has issued specifications have nominal cornering coefficients from 0.150 to 0.195. The HR78-15 on a 6.00 inch rim has a section width of 8.~5 inches and a height from bead to tread of 6.6 inches.
`
.
~08~S9~
A lighter weight tire is illustrated in Figures 4 and 5. The section ~idth is 8 inches but the tire has a side wall thickness of 0.23 inches. The radius of the outer side wall surface is 2.6 inches.
Tread width is 5~1 inches. The radial side ~all reinforcement 96 is 3 x .010 steel cable with 7 filaments per inch. Lateral reinforcing sheets 63, 64 are 4.60 and 4.90 inches wide, respectively, and each has 4 x 4 x .007 steel cable reinforcing with 14 filaments 97 per inch. Inextensible belt 65 is 4 inches wide and reinforced with 5 x .010 inch steel cable with 16 ~ilaments 98 per inch. Roll restraining hoops 81, 82 are of 6 x 5 x .037 steel ~-re. Rim step 78 has a radial dimension of 0.10 inch and a width of 1.95 inches.
Suitable elastomer compounds fnr the tire are identified by code number in Table A. The principal constituents and physical characteristics of the elastomer compounds are given in Table B.
... . . .. . . .. . .... .
s9~
TABLE A
. Tire Part Tire Figures 4,5 Tube Stock t.inside the T208 radial reinforcing) Bond Stock B320 .
;;` Sidewall C657 Tread C657 Hoop Filler V904 10BlS5~2 .. . . . ...
~ ~ r~~rl rlrl ~rl h ~ \\ \
o Q) O~rl R.4 ~ Q
E-l h 1 :~r~ 1 r~ ~I r-l cn o o Ou~ r~
t~ ~ r-l r-l O
~rl ~ o~o~o o\Oo\O o\O o\O
~t) O O O ~) O O
O O O 1~ 0 O
U O r-l(Y) r~ ) r-l r~ rl U~
r~ U~
Ul rl OO ~ N CO O
O U~ InO ~ ~ r-l O
) ot~
r-l~ r-l r l U~
O
~rl ~Oo\O o\O o\O d~ o\
~ OU~ OO O O
t~ 111 ~O O r l ~ O
~ l~~ r~ r-l 0~ .' a: I ~ ~
~ I~rl ~rl O O O O ~ O
1~ I U~ O O Ir) Is~ ~D O
m l~ ~ O ,~
I E~
_ ::
~ s, U~ ~
a~ ~ a) .
U~
O O L~ Lr) Ln ul CO ,: ' s~ .
Q
a) ~
~ ~ ~ ~ ~ ~Q
O Q a~ .~ rl Q I O
~rl S~ rl ,~ r~
o ~1 ~ ~ ~ ~ ~ u a U~ Q Q r~ Ul r~
O ~ r~ rl ~ p~ 0 O ,~,~ ~ r~ ~ 0 3 C ) ~ O Q h O t~
z ~ ~o m ~ z o\ o\ O o\ ~ r~
~ ~ o o s~
z z a~,~ m ~ m ~ ~ o 1~ co Lt~ ~r O O ~ L~ O r~ O
~ ~ ~ ~ C~
o m m V E~
o - . ,.,, ., , -The tire of Figures 4 and 5 has a cornering coefficient of .159. The tires can be operated at sub-stantially higher pressures than 30 psi with good ride characteristics. The cornering coefficient increases with inflation pressure. Accordingly, the tire can accommodate a significantly greater load than the HR78-15 tire. Conversely, a smaller tire incorporating the invention could be selected for service with a load capability of the HR78-15.
The open carcass HR78-15 tire weighs approxi-mately 32 pounds. The comparable tire of Figures 4 and 5 weighs 25 pounds.
The almost unlimited selection of elastomer materials and reinforcing available for the tire tread wall enables fabrication of tires of various sizes with a desired cornering coefficient. However, it is both expensive and time consuming to build and test a complete tire. We have determined that samples of tread material may be tested in simple beam deflection, providing information regarding stiffness which correlates predict-ably with the cornering coefficient of the tire using the material in the tread. This greatly simplifies the analysis of tread material and the design of tires. Figure 6 illustrates a section of tread material prepared for a beam deflection test. The dimension 115 of the sample 116 corresponds with the peripheral dimension of the tire tread. Dimension 117 corresponds with the transverse dimension of the tread. Three holes 118, 119 and 120 are spaced along the axis of the sample 116 parallel with ., , .. . ~, .,:.. ~ ... . .
~0~3~5~
dimension 115. The specimen is suspended from holes 118 and 120 and a deflecting force is applied to hole 119.
The deflection of the specimen is a measure of its resistance to lateral deformation.
The incremental deflection of the side walls of the tire is related to its multipressure, good ride performance. AS the tire is loaded, the incremental deflections at the junctures of the side walls with the rim and at the junctures of the side walls with the tread wall are uniform. This is to be contrasted with a conventional open carcass, beaded tire where the side wall is stiff in the area of the beads and the principal deflection occurs at the side wall-rim wall juncture.
So long as the tire side wall6 have this capacity for symmetric incremental deflection at the tread wall and rim wall, the multipressure, soft ride and the advantages of the invention in establishing the desired cornering coefficient are achieved. These side wall characteristics do not require the tube tire construction on a core as described in the Grawey patent. While this construction is desirable because it provides tire uniformity and lower cost, similar performance can be achieved with a crown overlap construction if the overlap is buried in the rim wall which is not subject to flexure or even in the tread wall where flexure is minimized. Moreover, it is not necessary that the side wall reinforcement be precisely in radial planes. A deviation of up to 10 is tolerable.
~o~s9%
It is preferable that the tread have the two bias reinforcing layers inside the inextensible 0 belt to eliminate the effect of the bias reinforcing on steer-ing. However, where the bias layers have sufficient resistance to peripheral expansion, as permitting a circumferential expansion of no more than 5%, the 0 belt may be omitted.
There are other characteristics of the tire which contribute to the cornering coefficient but to a lesser extent than the lateral tread reinforcement tire to rim connection and side wall fillers.
The tread width and elasticity of the tread material affect tread stiffness. The cornering coefficient is higher for a wider tread or stiffer material. However, excessive heat is generated in a stiff material and this is detrimental to tire life. The angle between the edge of the tread and the side wall, sometimes described as the tread shoulder angle, may vary substantially. The cornering coefficient is higher for a square relationship ~ than for a smaller angle ~2 .
The tube tires illustrated in Figures 4 and 5, may be manufactured with the procedures described in Grawey 3,776,792, a division of 3,606,921.
While preferred embodiments of the invention have herein been illustrated and described, this has been done by way of illustration and not limitation, and the invention should not be limited except as required by the scope of the appended claims.
s~z The tube tires illustrated in Figures 4, 5, 6 and 7 may be manufactured with the procedures described in Grawey 3,776,792, a division of 3,606,921.
While preferred embodiments of the invention have herein been illustrated and described, this has been done by way o illustration and not limitation, and the invention should not be limite~ except as required by the scope of the appended claims.
.. .. . . ... ...
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A radially reinforced pneumatic tire and rim assembly therefor, with a ratio of lateral force to load in a rolling turn sufficient to establish a corner-ing coefficient satisfactory for vehicle road use, comprising:
a pneumatic tire having an elastomer carcass with a peripheral inextensible annular tread wall, a pair of annular rim wall portions and a pair of opposed annular side walls each joining a lateral edge of the tread wall with a lateral edge of the respective rim wall portion, a pair of roll restraining hoops each connected to one of the rim wall portions, radial reinforcing in the side walls, the rim wall portions, and the tread wall, the construction of the tire being such that incremental deformation of the side walls at their junctures with the tread wall and rim wall portions is substantially symmetrical under load in the plane of the tire;
a rim having a pair of annular surfaces on which the tire rim wall portions are received;
means in said tire tread wall for imparting lateral stiffness thereto to resist bending of the footprint of the tire so that a substantial lateral force is developed in the tread wall in a rolling turn; and (Claim 1 continued):
means for securing the tire rim wall portions to the annular surfaces of the rim to restrain movement therebetween in a direction axial of the tire and rim so that the lateral force developed in the tire tread wall and transmitted through the side walls to the rim wall portions is transmitted from the rim wall portions to the rim, said securing means including a pair of radially outwardly extending annular rim surfaces provided on the rim each being positioned in motion restraining relation to the respective roll restraining hoop, preventing lateral movement thereof relative to the rim as a result of lateral force developed in a rolling turn, the radially outwardly extending annular rim surfaces and the roll restraining hoops being spaced axially inwardly of the juncture of the respective side wall and rim wall portion.
a pneumatic tire having an elastomer carcass with a peripheral inextensible annular tread wall, a pair of annular rim wall portions and a pair of opposed annular side walls each joining a lateral edge of the tread wall with a lateral edge of the respective rim wall portion, a pair of roll restraining hoops each connected to one of the rim wall portions, radial reinforcing in the side walls, the rim wall portions, and the tread wall, the construction of the tire being such that incremental deformation of the side walls at their junctures with the tread wall and rim wall portions is substantially symmetrical under load in the plane of the tire;
a rim having a pair of annular surfaces on which the tire rim wall portions are received;
means in said tire tread wall for imparting lateral stiffness thereto to resist bending of the footprint of the tire so that a substantial lateral force is developed in the tread wall in a rolling turn; and (Claim 1 continued):
means for securing the tire rim wall portions to the annular surfaces of the rim to restrain movement therebetween in a direction axial of the tire and rim so that the lateral force developed in the tire tread wall and transmitted through the side walls to the rim wall portions is transmitted from the rim wall portions to the rim, said securing means including a pair of radially outwardly extending annular rim surfaces provided on the rim each being positioned in motion restraining relation to the respective roll restraining hoop, preventing lateral movement thereof relative to the rim as a result of lateral force developed in a rolling turn, the radially outwardly extending annular rim surfaces and the roll restraining hoops being spaced axially inwardly of the juncture of the respective side wall and rim wall portion.
2. The tire and rim assembly of claim 1 in which the radially outwardly extending annular rim surfaces are positioned between the roll restraining hoops.
3. The tire and rim assembly of claim 2 in which the tire rim wall has a generally straight inner surface in an unstressed condition, the radially outwardly extending annular rim surfaces deforming the tire rim wall outwardly between the lateral facing edges of the roll restraining hoops.
4. The tire and rim assembly of claim 1 wherein the rim has a centrally located radial step, the radially outwardly extending annular rim surfaces being lateral edges of the radial step.
5. The tire and rim of claim 1 in which the means securing the tire rim wall portions to the annular surfaces of the rim prevents the tire rim wall portions from moving inwardly with respect to the annular surfaces of the rim in response to the force developed in a rolling turn.
6. The tire and rim of claim 1 in which said tread wall lateral stiffening means is a pair of radially spaced peripheral breaker strips with reinforcing elements disposed at a bias angle, the bias angles of the two strips being equal and displaced in opposite directions from the longitudinal plane of the tire.
7. The tire and rim of claim 1 in which said tread wall includes:
a peripheral inextensible belt with reinforcing elements at substantially 0° with respect to the plane of the tire; and the lateral stiffening means is a pair of radially spaced peripheral breaker strips with reinforcing elements disposed at a bias angle, the bias angles of the two strips being equal and displaced in opposite directions from the longitudinal plane of the tire.
a peripheral inextensible belt with reinforcing elements at substantially 0° with respect to the plane of the tire; and the lateral stiffening means is a pair of radially spaced peripheral breaker strips with reinforcing elements disposed at a bias angle, the bias angles of the two strips being equal and displaced in opposite directions from the longitudinal plane of the tire.
8. The tire and rim of claim 7 in which said inextensible belt is spaced radially outside the breaker strips.
9. The tire and rim of claim 7 in which the width of the inextensible belt is less than the width of the breaker strips.
10. The tire and rim of claim 9 in which the width of the outer breaker strip is less than the width of the inner breaker strip.
11. The tire and rim of claim 1 in which the tire has an annular body of elastomer between the lateral edges of the tread wall and the outer surface of the adjacent side wall.
12. The tire rim of claim 1 in which the tire has an annular body of elastomer between the outer edge of each roll restraining hoop and the inner surface of the adjacent side wall.
13. The tire and rim assembly of claims 1, 3 or 5 wherein the pneumatic tire is a tube tire.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US73056776A | 1976-10-07 | 1976-10-07 | |
| US730,567 | 1976-10-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1081592A true CA1081592A (en) | 1980-07-15 |
Family
ID=24935874
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA286,699A Expired CA1081592A (en) | 1976-10-07 | 1977-09-14 | Pneumatic tire and rim therefor |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5347603A (en) |
| CA (1) | CA1081592A (en) |
| FR (1) | FR2366944A1 (en) |
| GB (1) | GB1584184A (en) |
| IT (1) | IT1084885B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU523430B2 (en) * | 1978-07-31 | 1982-07-29 | Goodyear Tire And Rubber Company, The | Radial tire |
| US4682640A (en) * | 1982-06-21 | 1987-07-28 | The Goodyear Tire & Rubber Company | Circumferential conduit means for inflating a closed torus tire |
| JPS6424602U (en) * | 1987-08-04 | 1989-02-10 | ||
| FR2660900A1 (en) * | 1990-04-11 | 1991-10-18 | Michelin & Cie | ASSEMBLY COMPRISING A TORNE PNEUMATIC AND METHOD FOR MANUFACTURING THE SAME. |
| WO2023178296A1 (en) | 2022-03-17 | 2023-09-21 | Avery Dennison Corporation | Laser printable, flexible drum labels |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1047921A (en) * | 1963-01-31 | 1966-11-09 | Dunlop Rubber Co | Improvements in or relating to pneumatic tyres |
| US3318357A (en) * | 1965-04-23 | 1967-05-09 | Gen Tire & Rubber Co | Pneumatic tire |
| DE1779058B1 (en) * | 1968-07-02 | 1970-04-02 | Berckheim Graf Von | Device for establishing an electric field in rooms and vehicles |
| US3750733A (en) * | 1971-12-14 | 1973-08-07 | H Brewer | Quick change-replaceable tread pneumatic tire |
| US3897814A (en) * | 1974-03-11 | 1975-08-05 | Caterpillar Tractor Co | Tire tread belt |
| DE2430890C2 (en) * | 1974-06-27 | 1985-05-23 | Continental Gummi-Werke Ag, 3000 Hannover | Vehicle wheel with a pneumatic tire |
| US4085786A (en) * | 1975-11-19 | 1978-04-25 | The Goodyear Tire & Rubber Company | Integrally built and cured tire and wheel assembly |
-
1977
- 1977-07-26 GB GB3126877A patent/GB1584184A/en not_active Expired
- 1977-09-13 IT IT2747977A patent/IT1084885B/en active
- 1977-09-14 JP JP11118477A patent/JPS5347603A/en active Granted
- 1977-09-14 CA CA286,699A patent/CA1081592A/en not_active Expired
- 1977-09-16 FR FR7728053A patent/FR2366944A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB1584184A (en) | 1981-02-11 |
| IT1084885B (en) | 1985-05-28 |
| JPS5347603A (en) | 1978-04-28 |
| FR2366944A1 (en) | 1978-05-05 |
| FR2366944B1 (en) | 1982-04-16 |
| JPS621B2 (en) | 1987-01-06 |
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| MKEX | Expiry |