JP2002514536A - Molding and installation of asymmetric race tires - Google Patents

Abstract

SUMMARY OF THE INVENTION Loss of tire contact area along the tire's inner shoulder to the elliptical race course, which occurs during chassis roll and lateral deflection, is reduced by providing an asymmetric molded tire. . The tires are defined by an asymmetric outer tread cross-section and the race vehicle is such that, for the race course, the axially outer portion of each tire's asymmetric tread area has a greater shoulder drop than the opposite tire shoulder. Mounted on the rear axle. The shoulder drop is the difference between the radial maximum diameter of the tread measured on the outer tread contour and the tread diameter at the tread end.

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD The present invention relates generally to tires for use in vehicles having a suspension system that allows little or no camber adjustment. In particular, the present invention relates to racing tires having improved lateral force characteristics for use on fixed rear axle race cars.

BACKGROUND OF THE INVENTION Laboratory research has shown that the net cornering force of most tires is generated in the region of the shoulder inward in the direction of rotation. Rolls and lateral deflections outward tend to lift this inner shoulder, reducing the cornering ability of the tire. In many vehicles, especially high performance or racing vehicles, the vehicle suspension system compensates for the reduced cornering ability due to cambering of the wheels. In cambering, the tops of the wheels and tires are tilted toward the center of the turning radius to maximize cornering forces.

For racing vehicles participating in NASCAR racing, such as the Winston Cup and the Bush Series Grand National Division, cambering of tires causes the tires and the tops of the wheels to lean inward toward the center of the elliptical track. . The effect of such cambering on the contact area of the tire as it travels around the track is that the contact area becomes oval in a straight section and a large radius goes into the track. Due to the roll and the lateral deflection, this contact area becomes more elliptical during cornering. This elliptical contact area is preferred because it allows a more even distribution of force between the tread sides during cornering and provides more stable high speed cornering.

[0004] However, for NASCAR vehicles, suitable approved vehicles prohibit or restrict rear axle cambering, so that roll and lateral deflection are not offset during cornering. When the rear axle race tire experiences significant lateral forces during high speed cornering due to lack of camber, the contact area configuration becomes oval and a large radius is directed outwards of the turn. This results in a loss of contact area along the inner shoulder of the tire for rotation and reduced cornering stability for the vehicle.

[0005] The off camber half of the tire requires less head drop than the on camber side to support a given load. The shoulder drop and cross section of the tire determine the relationship between load, camber, and footprint at the shoulder. Prior art tires designed to compensate for reduced tire camber presets employ asymmetric tires having unequal length sidewalls. The tire did not specifically change the load / footprint relationship along the off camber shoulder.

US Pat. No. 3,435,874 discloses modifying the tread section or belt section to achieve the desired cancellation of structural and conical forces to reduce the total lateral slip force. The tread cross-section can be inclined at one angle from one tread end to the opposite tread end, or at a different angle.

[0007] US Pat. No. 5,591,282 discloses a tire and vehicle system configured to compensate for camber loss on the rear axle of the vehicle. There, a support member is disposed on the surface of the inboard sidewall of the tire. However, such a system adds weight to the tire, which is undesirable for racing tires that require optimized weight reduction.

US Pat. No. 5,620,538 discloses an asymmetric racing tire for use on an elliptical race course. The tire is designed to reduce belt end separation outside the tire relative to the wheel on which it is mounted. An asymmetric tire has an outer diameter and thickness in the outer tread area that are greater than an outer diameter and thickness in the inner tread area. Such tires also increase in weight if they do not compensate for the camber loss on the rear axle of the vehicle.

SUMMARY OF THE INVENTION The present invention is directed to a rear axle racing tire by eliminating the loss of tire contact area along the tire's inner shoulder with respect to vehicle cornering during chassis roll and lateral deflection. A method for improving the lateral force characteristics of the above is disclosed.

[0010] In another aspect of the present invention, a tire disposed on a rear axle of a racing vehicle running on a circular race course is disclosed. The cross section of the outer tread area of the tread which is arranged further axially outward toward the outside of the race course than the center line of the tire, and further axially inside toward the inside of the race course than the center line of the tire. The cross section of the inner tread region of the tread portion is asymmetric. The axial exterior of the asymmetric tread area of each tire mounted on the rear axle of the vehicle has a greater shoulder drop relative to the race course than the axial interior of the asymmetric tread area. Here, the shoulder drop is the difference between the radial maximum diameter of the tread measured on the outer tread profile and the tread diameter at the tread end.

[0011] Further according to the disclosed invention, the ratio of the shoulder drop of the axially outer shoulder of each tire mounted on the rear axle of the non-cambered vehicle to the shoulder drop of the axially inner shoulder of the tire. Is equal to 1.0 to 4.5.

According to the invention further disclosed, the ratio of the shoulder drop of the axially outer shoulder of each tire mounted on the rear axle of the non-camber vehicle to the shoulder drop of the axially inner shoulder of the tire. Is equal to 1.5 to 2.5.

[0013] Another disclosed invention is a method of mounting tires on a rear axle of a racing vehicle running on an elliptical race course. The cross section of the outer tread area of the tire tread, which is arranged further outward in the axial direction toward the outside of the race course than the center line of the tire, and further inward in the axial direction toward the inside of the race course than the center line of the tire Is asymmetric with the cross-section of the inner tread region of the tire tread located at The tire has a shoulder drop, which is the difference between the radial maximum diameter of the tread and the radial diameter of the tread at the tread end, at the axially outer portion of the tire with respect to the race course, is greater than the axially inner portion of the tire. Installed where there is a shoulder drop.

Furthermore, according to the disclosed method of mounting a tire, the ratio of the axially outer shoulder drop to the axially inner shoulder drop is in the range of 1.0 to 4.5.

Further, according to the disclosed method of mounting a tire, the ratio of the axially outer shoulder drop to the axially inner shoulder drop is in the range of 1.5 to 2.5.

[0016] Another disclosed invention is a method of forming an asymmetric tire by providing a tire, an asymmetric mold, and forming the tire in the mold. An asymmetric mold is a tread cross-section having axially opposite tread shoulder regions, each shoulder region having a maximum radial height of the mold tread cross-section, and a tread centerline extending radially of the mold tread cross-section. It has a tread cross section having a minimum height. Each shoulder region is defined by a shoulder drop equal to the difference between the maximum radial height of the shoulder region and the minimum radial height of the tread mold section at the tread centerline. The shoulder drop in the first shoulder region is greater than the shoulder drop in the opposite second shoulder region.

According to the further disclosed method of forming an asymmetric tire, the ratio of the shoulder drop of the first shoulder region to the shoulder drop of the opposite second shoulder region is 1.0 to 4%. .5.

Furthermore, according to the disclosed method of forming an asymmetric tire, the ratio of the shoulder drop of the first shoulder region to the shoulder drop of the opposite second shoulder region is between 1.5 and 1.5. 2.5

Definitions “Apex” means an elastomeric filler located between the ply and the turnup ply, radially above the bead core.

“Asymmetric tread” means a tread having a tread shape that is not symmetric with respect to the center line CL or the equatorial plane EP of the tire.

“Axial” and “axially” are used herein to refer to lines or directions that are parallel to the axis of rotation of the tire.

A “bead” is ply corded and may or may not have other reinforcing members such as flippers, chippers, apex, toe guards and chafers, and fits the design rim Means the part of the tire that has an annular tension member shaped.

A “belt” is a ply of at least two annular layers or parallel reinforcement cords having the same angle with respect to the equatorial plane of the tire as the parallel reinforcement cords in the carcass ply.

“Camber” refers to the inclination of the front wheels of the vehicle, which is positive outward at the top.

A “carcass” is a tire structure that includes beads, apart from the belt structure, tread, undertread, and sidewall rubber on the plies.

“Casing” means the carcass, belt structure, beads, sidewalls, and all other parts of the tire except for the tread and undertread.

“Circumferential” means a line or direction extending along the periphery of the surface of an annular tire parallel to the equatorial plane (EP) and perpendicular to the axial direction.

“Equatorial plane (EP)” means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread.

“Groove” means an elongated void area that extends circumferentially or laterally around the tread in a straight, curved, or zig-zag manner.

“Inside” of the disclosed invention means the side of the tire closest to the center of the elliptical race course when the tire is mounted on a vehicle located on the elliptical race course, and “outside” means Means the side of the tire closest to the outermost side of the elliptical race course when mounted on a vehicle located on the elliptical race course.

A “lateral edge” is a tread, defined by a plane parallel to the equatorial plane and intersecting the outer edge of the axially outermost traction lug at a radial height of the inner tread surface. Means the outermost edge in the axial direction.

“Radial tires” are belted, with ply cords extending from bead to bead arranged at a cord angle between 65 ° and 90 ° with respect to the equatorial plane of the tire,
Or a pneumatic tire limited in the circumferential direction.

“Cross section height” means the radial distance from the nominal rim diameter to the outer diameter of the tire at the equatorial plane.

“Shoulder” means the upper portion of the sidewall just below the tread edge that affects cornering. Tread shoulder or shoulder rim refers to the portion of the tread near the shoulder.

“Sidewall” means the portion of the tire between the tread and the bead.

A “tread” is a molded rubber component that includes a portion of a tire that, when secured to a tire casing, comes into contact with the road under normal inflation and under a normal load.

The “tread center line” (CL) is an intersection line between the equatorial plane (EP) and the tread.

“Tread radius” is the radius or combination of radii that outlines the tread profile.

“Tread arc width” means the length of the arc on the tread surface in the axial direction, ie, in a plane parallel to the axis of rotation of the tire.

(Detailed Description of the Invention) FIG. 1 shows a conventional tire mold 1. The tread cross section of a typical symmetric mold is the width of its tread arc, T.D. A. W. , And the relationship between the tread width and the shoulder mold drop Ds. The shoulder mold drop Ds is defined as the difference in diameter at the centerline of the mold, the minimum radial mold height and its furthest shoulder, the maximum radial mold height along the tread cross-section. The radial mold minimum height at the centerline of the mold corresponds to the radial maximum height of the formed tire, and the radial mold maximum height at the furthest shoulder is at the furthest shoulder of the formed tire. Corresponds to the radial minimum height. The radial maximum and minimum heights are for the outermost mold surface as shown in FIG.

FIG. 2 shows a tire mold 2 according to the disclosed invention. The mold tread cross section is asymmetric with respect to the circumferential center line. Each shoulder area of the tread section is defined by a shoulder drop equal to the difference between its radial mold maximum height and the radial mold maximum height at the tread section centerline. First shoulder region has a shoulder drop D _O, greater than the shoulder drop D _I of the second shoulder drop of the opposite side. The tire inserted into the mold is the tire at any stage of vulcanization. The tire is formed by a conventional tire forming method. The tire can be symmetrically shaped or asymmetrically shaped with a bead structure, sidewall structure, or variations in sidewall height. As with conventional tires, here the radial mold minimum height at the mold centerline corresponds to the radial maximum height of the molded tire, and the radial mold maximum height at the furthest shoulder is Corresponds to the radial minimum height at the farthest shoulder of the tire. The radial maximum and minimum heights are for the outermost mold surface as shown in FIG.

FIG. 3 shows a tire according to the disclosed invention. The tire 10 is a low aspect ratio tire. Prior to insertion into the mold 2, the tire structure is symmetric except for any preforming of the tread pattern. The tire 10 has a tread portion 12, a bead portion 14,
16 and sidewall portions 18 and 20. The right and left sidewall portions 18 and 20 are respectively joined to the right and left bead portions 14 and 16 and extend radially outward of the tire. The tread portion 12 extends in the circumferential direction of the tire and is provided between the left and right sidewall portions 18 and 20.

The tire 10 is provided with a carcass layer 22 including at least one reinforcing cord. The carcass layer 22 is formed from one bead portion 14 to the opposite bead portion 16.
And has a main portion 24 that extends under the tread portion 12 and reaches the two ends 26 and 28. Each end 26, 28 is folded around a respective annular bead core 30 provided in each bead 14, 16 of the tire 10 and extends a respective radial distance into each sidewall 18, 20. Bead core 30 can be formed in any known conventional shape.

A bead filler 32 is located radially outward of each bead core 30 and within the main carcass portion 24 and folded ends 26, 28 of the carcass. The bead filler 32 extends radially outward toward the sidewall portions 18 and 20 of the tire 10. The bead filler 32 has a substantially triangular shape, and the bead core 30
The width is tapered toward the sidewalls 18 and 20 from.

A plurality of belt layers 34 extend radially outward of the carcass layer 22 and circumferentially around the tire 10. The belt layer 34 is made of an elastomer-embedded reinforcing cord that is arranged to be inclined with respect to the circumferential direction of the tire 10.

The tread 12 can be provided with circumferentially or laterally extending grooves 36, sipes, and slots, or the tread can be a smooth surface without any grooving on the tread surface. . As those skilled in the art are aware, the characteristics of the tread depend on the racing conditions. This smooth surface is preferred for dry racing conditions, while grooved tires are preferred for wet track racing. In racing, any treading of the tread may also be determined by a suitable licensing authority.

In the asymmetric head mold design of the present invention, the shoulder head D_SDiffers at the opposite shoulder
ing. The axially outer shoulder 42 has a greater shoulder drop D than the opposite shoulder 44._OWith
I do. Shoulder drop D of the axially outer shoulder 42_OThe shoulder drop D of the axially inner shoulder 44 _I Is in the range of 1.0 to 4.5. Axial outer shoulder drop D_O Of the axially inner shoulder drop D_IIs preferably between 1.5 and 2.5.
Good. It is the outer shoulder drop D_OTo the conventional head D_SIncreased to be larger than
Or the inside shoulder drop D_ITo the conventional head D_SReduced so that
Is achieved. The difference in shoulder drop depends on the given load and camber conditions.
A choice is made to optimize the tire footprint for the setting.

Due to the greater head drop of the axial outer shoulder 42, the axial inner tread half 40 has a flatter tread cross-section than the opposite tread half 38 which also has a head drop. The radius of curvature defining the axially outer tread half 38 is smaller than the radius of curvature defining the axially inner tread half 40.

FIG. 4 shows the difference in head when the tire of the present invention is compared with a conventional tire.
A conventional tire cross section is represented by a broken line, and a solid line cross section is that of the tire of the present invention.
During cornering of the vehicle, the cornering force causes the tire to roll out of turn. Due to these cornering forces, the outer shoulder 44 runs closer to the ground when operating in off camber conditions, or runs at a higher load when in contact with the ground. By using a smaller mold drop D _I on the inner shoulder 44, the area of the contact area is increased. Raising the inner shoulder 44 of the asymmetrically formed tire 10 from the ground requires more severe off-camber conditions.

In combination with various molding shoulder heads, the tread width, molding bead width, section width, and maximum section width height can also be varied on both sides of the mold according to known prior art.

The asymmetric drop mold enhances the rear cornering ability of a solid rear axle, such as a NASCAR vehicle. These vehicles have little or no negative static camber to offset the effects of roll and lateral deflection. For an elliptical track racer that always turns to the left, the low head half of the tire should be mounted to the left of both rear tires, as viewed from above.

The disclosed mold shape can also be applied to road racing cars without camber adjustable in the rear axle. In such a race where the car turns left and right, the low drop half is applied to both rear tires so as to obtain an asymmetrical advantage on the inner shoulder of the outer tire for a given turn. Should be mounted towards the car center line.

Various modifications of the invention can be envisioned with reference to the invention described herein. While exemplary embodiments and details have been shown for purposes of illustrating the invention, those skilled in the art will appreciate that various changes and modifications may be made without departing from the scope of the invention. Accordingly, modifications that fall within the full intended scope of the invention as defined by the appended claims, may be made in the specific embodiments described above.

[Brief description of the drawings]

FIG. 1 shows a prior art mold for a race tire.

FIG. 2 illustrates a tire mold according to the disclosed invention.

FIG. 3 illustrates a tire molded according to the disclosed invention.

FIG. 4 is a diagram comparing the relationship between the conventional tire and the tire of the present invention and the road surface during cornering of the tire.

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] January 4, 2000 (200.1.4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

US Pat. No. 5,620,538 discloses an asymmetric racing tire for use on an elliptical race course. The tire is designed to reduce belt end separation outside the tire relative to the wheel on which it is mounted. An asymmetric tire has an outer diameter and thickness in the outer tread area that are greater than an outer diameter and thickness in the inner tread area. Such tires also increase in weight if they do not compensate for the camber loss on the rear axle of the vehicle. European Patent 755,808A2, the drop of the two shoulders an unequal tire maximum height is deviated from the center line, discloses a tire for passenger cars having an inclined tread contour. When the tire is mounted on the vehicle, the shoulder having a shoulder portion maximum drop should be mounted separately from the vehicle body.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29K 105: 24 B29K 105: 24 B29L 30:00 B29L 30:00 (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD) , RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE ES, FI, GB, GE, GH, GM, GW, HU, ID, IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD , MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, U Z, VN, YU, ZW (71) Applicant 1144 East Market Street, Akron, Ohio 44316-0001, U.S.A. S. A. (72) Inventor Stacker, Joan, Gregory United States 44224 Storr Oak Road, Ohio 3576 (72) Inventor Campbell, Richard, Berkeley United States 44646 Massillon, Ohio. W. Rats A Venue 7827 (72) Inventor Schmalix, Charles, Kennis United States 44614 Canal Fulton, Ohio. W. Green Meadow Avenue 8882 (72) Inventor Lazeration, Joel, Joseph United States 44321 Acron Treetop Drive, Ohio 4690 F-term (reference) 4F202 AH20 AR12 CA21 CB01 CU01 4F203 AH20 AR12 DA11 DB01 DC01 DL10

Claims (12)

[Claims] 1. A tire 10 disposed on a rear axis of a racing vehicle running on an elliptical race course, further axially outward from the center line CL of the tire 10 toward the outside of the elliptical race course. The cross section of the outer tread region 38 of the tread portion 12 of the tire 10 and the tread portion 12 of the tire 10 disposed further axially inward toward the inside of the race course than the center line CL of the tire 10. In the tire, wherein the cross-section of the inner tread region 40 is asymmetric, the shoulder drop is the difference between the radial maximum diameter of the tread 12 measured on the outer tread profile and the tread diameter at the tread ends 42,44. At the time, the axially outer portion 38 of the asymmetric tread area 12 of each tire 10 mounted on the rear axle of the vehicle
, To the race course, asymmetric race tires 10 having a shoulder drop D _I is greater than the shoulder drop D _O of the axially inner portion 40 of the asymmetric tread area 12, characterized in that. Wherein axially outer shoulder drop D ratio axially inner shoulder drop D _I of _O is at least 1.0 to the range of 4.5, asymmetric race tires 10 according to claim 1, wherein. Wherein an axially outer shoulder drop D ratio axially inner shoulder drop D _I of _O is in the range of from 1.5 to 2.5, according to claim 2 asymmetric race tires 1 according
0. 4. A tie on a rear axle of a racing vehicle running on an elliptical race course
A method of attaching the tire 10 to the tire 10 with respect to the center line CL of the tire 10.
The tire track of the tire 10 which is arranged further outward in the axial direction toward the outside of the course.
Between the cross section of the outer tread region 38 of the tread portion 12 and the center line CL of the tire 10.
The tread of the tire 10 arranged further inward in the axial direction toward the inside of the scours
The tire 10 has an asymmetrical cross section of the inner tread region 40 of the portion 12.
Wherein the shoulder drop is determined by a maximum radial diameter of the tread 12 measured on the outer tread profile.
When the difference from the tread diameter at the tread edges 42, 44, the race course
The axially outer portion 38 of the asymmetric tread region 12 of each tire 10 is asymmetric.
Shoulder drop D of the axially inner portion 40 of the tread region 12_IShoulder drop D larger than _O A method of mounting an asymmetric race tire 10, comprising: 5. The axially outer shoulder drop D ratio axially inner shoulder drop D _I of _O is in the range of from 1.0 4.5, 4. asymmetric race tires 1 according
0 mounting method. 6. axially outer shoulder drop D ratio axially inner shoulder drop D _I of _O is in the range of from 1.5 to 2.5, according to claim 5 asymmetric race tires 1 according
0 mounting method. 7. Providing a raw tire, providing an asymmetric mold 2 and providing a tire 10
And forming the asymmetric tire 10 by molding the tire 10 in the mold 2, wherein the asymmetric mold 2 is a tread cross-section 12 including axially opposed tread shoulder regions 38, 40, Each shoulder region 38, 40 has a maximum radial height of the molded tread cross section, a tread centerline CL has a minimum radial height of the molded tread cross section 12,
Each shoulder region 38, 40 is defined by a shoulder drop equal to the difference between its radial maximum height and the radial minimum height of the tread mold section at the tread centerline, and the shoulder drop height of the first shoulder region 38. is D _O is greater than the shoulder drop height D _I of the opposite side of the second shoulder region 40, the molding method of the asymmetric race tires 10, characterized in that. Of 8. shoulder drop D _O of the first shoulder region 38, the ratio of the shoulder drop D _I opposite the second shoulder region 40 within the range of from 1.0 4.5 The method for forming an asymmetric race tire 10 according to claim 7. Of 9. shoulder drop D _O of the first shoulder region 38, the ratio of the shoulder drop D _I opposite the second shoulder region 40 within the range of from 1.5 to 2.5 The method for forming an asymmetric race tire 10 according to claim 8. 10. A mold 2 for an asymmetric tire 10, wherein the mold 2
Is the mold tread cross section 12, the mold tread center line CL, the axially opposite side
Including the mold tread shoulder regions 38, 40, the mold tread cross section 12
The asymmetric molded tread section has an asymmetric shape, wherein each shoulder region 38, 40 has a maximum radial height of the molded tread section,
The red center line CL has the minimum height in the radial direction of the molded tread cross section 12 and each shoulder
The part areas 38, 40 have a maximum height in the radial direction and a mold at the tread center line.
Limited by a shoulder drop equal to the difference in the minimum radial height of the red cross-section, the shoulder drop D of the first shoulder region 38_OIs the shoulder drop D of the opposite second shoulder region 40 _I A mold 2 for an asymmetric tire 10. Of 11. shoulder drop D _O of the first shoulder region 38, the ratio of the shoulder drop D _I opposite the second shoulder region 40 within the range of from 1.0 4.5 The mold according to claim 10. Of 12. shoulder drop D _O of the first shoulder region 38, the ratio of the shoulder drop D _I opposite the second shoulder region 40 within the range of from 1.5 to 2.5 The mold according to claim 11, wherein the mold is provided.