PNEUMATIC VEHICLE TYRE COMPRISING A CARCASS

Abstract

Pneumatic vehicle tyre comprising a carcass (3), wherein the carcass (3) has two carcass plies (31, 32), wherein each carcass ply (31, 32) has reinforcements which are arranged inside the carcass ply (31, 32) substantially parallel to each other. The problem addressed by the invention is to provide a pneumatic vehicle tyre which likewise creates a high quality impression of sufficient robustness to a viewer and, in the process, is cheaper to produce and has a reduced rolling resistance. The invention is characterised in that the product EF1 of the average modulus of elasticity of the reinforcements, as measured with an extension of 2%, of the first carcass ply (31) and the thread density of the reinforcements of the first carcass ply (31), and the product EF2 of the average modulus of elasticity of the reinforcements of the second carcass ply (32) and the thread density of reinforcements of the second carcass ply (32), satisfy the relationship EF1>EF2.

Claims

1.-9. (canceled)

10. A pneumatic vehicle tire comprising at least one profiled tread, a belt, two side walls, two bead cores and a carcass, wherein the carcass has two carcass plies, wherein each carcass ply has reinforcement members which are arranged substantially parallel to one another within the carcass ply and which are embedded in elastomer material, wherein the first carcass ply runs in coherent fashion and, in so doing, extends at least from one bead core to the other bead core, runs around each bead core from axially inside to axially outside, and extends in a carcass upturned portion in the direction of the belt, and wherein, at least in the region of a belt edge, the second carcass ply is arranged radially outside the first carcass ply; and, wherein a product EF1 of mean modulus of elasticity of the reinforcement members of the first carcass ply and strand density of the reinforcement members of the first carcass ply, and a product EF2 of mean modulus of elasticity of strength members of the second carcass ply and strand density of the reinforcement members of the second carcass ply, satisfy the relationship EF1>EF2, and wherein the modulus of elasticity of a reinforcement member is in each case measured at an elongation of 2% in accordance with ASTM D885.

11. The pneumatic vehicle tire as claimed in claim 1, wherein the reinforcement members of the first carcass ply and the reinforcement members of the second carcass ply are formed from the same material.

12. The pneumatic vehicle tire as claimed in claim 1, wherein a product FF1 of mean fineness of the reinforcement members of the first carcass ply and the strand density of the reinforcement members of the first carcass ply, and a product FF2 of mean fineness of the reinforcement members of the second carcass ply and the strand density of the reinforcement members of the second carcass ply, satisfy the relationship FF1>FF2.

13. The pneumatic vehicle tire as claimed in claim 1, wherein the second carcass ply extends in coherent fashion at least from one bead core to another bead core.

14. The pneumatic vehicle tire as claimed in claim 1, wherein the second carcass ply is a split ply composed of two ply parts, in that, at least from the radially outer height of each bead core, a ply part runs in a radial direction (rR) in the direction of the belt, is led as far as under the belt and ends there, and in that the two ply parts are arranged axially spaced apart from one another in the belt region.

15. The pneumatic vehicle tire as claimed in claim 1, wherein the second carcass ply at least in one tire half runs in a region of a carcass upturned portion of the first carcass ply and axially outside the carcass upturned portion of the first carcass ply.

16. The pneumatic vehicle tire as claimed in claim 1, wherein the second carcass ply at least in one tire half runs in the region of a carcass upturned portion of the first carcass ply and axially within the carcass upturned portion of the first carcass ply.

17. The pneumatic vehicle tire as claimed in claim 1, wherein the reinforcement members of the two carcass plies, with opposite gradient direction, enclose an approximately equal angle of 70° to 90°, relative the circumferential direction of the pneumatic vehicle tire.

18. The pneumatic vehicle tire as claimed in claim 1, wherein the pneumatic vehicle tire is a tire for a passenger motor vehicle.

19. The pneumatic vehicle tire as claimed in claim 1, wherein the pneumatic vehicle tire is a tire for a utility vehicle.

Description

[0021] Further features, advantages and details of the invention will now be discussed in more detail on the basis of the drawings, which illustrate schematic exemplary embodiments. In the drawings:

[0022] FIG. 1 shows a cross section through a passenger motor vehicle tyre;

[0023] FIG. 2 shows a cross section through an overlapping connection of a carcass ply of a passenger motor vehicle tyre according to the invention;

[0024] FIG. 3 and FIG. 4 each show a cross section through an exemplary embodiment of the carcass arrangement in a passenger motor vehicle tyre.

[0025] FIG. 1 schematically shows a cross section through a passenger motor vehicle pneumatic tyre. The major constituent parts from which the illustrated tyre is constructed are a profiled tread 1, a belt 2 which is covered radially at the outside by a belt bandage 13, an inner layer 4 which is of substantially air-tight form, beads 5 with bead cores 6 and bead core profiles 7, side walls 8, and a carcass 3 which extends from one bead core 6 to the other bead core 6 and is looped around these. The carcass 3 is of two-ply form, wherein the carcass plies are not illustrated individually in FIG. 1. The belt 2 has two plies (not illustrated in any more detail) which, in a known manner, have reinforcement members composed of steel cord which are embedded in a rubber mixture, which reinforcement members run parallel to one another within each ply. The steel cords of one ply are in this case oriented in a criss-crossing arrangement with respect to the steel cords of the second ply. The carcass 3 also has reinforcement members which are embedded in elastomer material and which run in a radial direction and which are composed of a textile material or of steel cord, which reinforcement members are arranged substantially parallel to one another within each carcass ply, and wherein each carcass ply is of closed form in a circumferential direction of the pneumatic vehicle tyre.

[0026] FIG. 2 to FIG. 4 each show a cross section through an exemplary embodiment of a carcass ply arrangement in a passenger motor vehicle tyre. The carcass ply arrangements that are shown are suitable for the passenger motor vehicle tyre shown in FIG. 1.

[0027] In FIG. 2 to FIG. 4, the first carcass ply 31 runs in coherent fashion and extends in this case at least from one bead core 6 to the other bead core 6. Furthermore, the first carcass ply 31 runs around each bead core 6 from axially inside to axially outside and extends, in a carcass upturned portion 3a, in the direction of the belt 2. In the regions of the two belt edges, the second carcass ply 32 is arranged radially outside the first carcass ply 31. The arrangement of the two carcass plies 31, 32 is symmetrical with respect to the tyre halves. All of the reinforcement members of the first carcass ply 31 are of identical form. All of the reinforcement members of the second carcass ply 32 are also of identical form. The reinforcement members of the two carcass plies 31, 32, with opposite gradient direction, enclose an approximately equal angle of 85° to 90°, with the circumferential direction of the pneumatic vehicle tyre.

[0028] In FIG. 2, the second carcass ply 32 also extends in coherent fashion at least from one bead core 6 to the other bead core 6. The second carcass ply 32 runs, in the region of the carcass upturned portion 3a of the first carcass ply 31, axially outside the carcass upturned portion 3a of the first carcass ply 31, and ends there without being looped around the bead core 6.

[0029] The product EF1 of the mean modulus of elasticity of the reinforcement members of the first carcass ply 31 and the strand density of the reinforcement members of the first carcass ply 31 and the product EF2 of the mean modulus of elasticity of the strength members of the second carcass ply 32 and the strand density of the reinforcement members of the second carcass ply 32 satisfy the relationship 1.5×EF2≧EF1≧1.3×EF2, wherein the modulus of elasticity of a reinforcement member is in each case measured at an elongation of 2% in accordance with ASTM D885. Furthermore, the product FF1 of the mean fineness of the reinforcement members of the first carcass ply 31 and the strand density of the reinforcement members of the first carcass ply 31 and the product FF2 of the mean fineness of the reinforcement members of the second carcass ply 32 and the strand density of the reinforcement members of the second carcass ply 32 satisfy the relationship 1.5× FF2≧FF1≧1.3×FF2.

[0030] In FIG. 3, too, the second carcass ply 32 extends in coherent fashion at least from one bead core 6 to the other bead core 6. The second carcass ply 32 runs, in the region of the carcass upturned portion 3a of the first carcass ply 31, axially within the carcass upturned portion 3a of the first carcass ply, and is looped around the bead core 6 from axially inside to axially outside.

[0031] Here, the reinforcement members of the two carcass plies 31, 32 are composed of polyester. The product EF1 and the product EF2 approximately satisfy the relationship EF1=1.4× EF2. Furthermore, the product FF1 and the product FF2 satisfy the relationship 1.5× FF2≧FF1≧1.3×FF2. The reinforcement members of the first carcass ply 31, with an equal and opposite gradient angle, enclose an angle of approximately 89° with the circumferential direction of the pneumatic vehicle tyre.

[0032] In FIG. 4, the second carcass ply 32 is a split ply composed of two ply parts 321, 322. From the radially outer height of each bead core 6, a ply part 321, 322 runs in the radial direction toward the belt 2. The ply parts 321, 322 are led as far as under the belt 2 and end there. Here, the two ply parts 321, 322 are arranged spaced apart from one another in the region of the belt 2. In the region of the carcass upturned portion 3a of the first carcass ply 31, the second carcass ply 32 runs axially within the carcass upturned portion 3a of the first carcass ply 31 and axially within the bead core 6, and ends there without being looped around the bead core 6.

[0033] Here, the reinforcement members of the first carcass ply 31 and the reinforcement members of the second carcass ply 32 are composed of polyester. The reinforcement members of the first carcass ply 31 are cords composed of two yarns with a fineness of 1440 dtex which are twisted together at the ends and which are arranged with a strand density of 105 epdm. The reinforcement members of the second carcass ply 32 are cords composed of two yarns with a fineness of 1100 dtex which are twisted together at the ends and which are arranged with a strand density of 100 epdm. The reinforcement members of the two carcass plies 31, 32, with opposite gradient direction, enclose an approximately equal angle of approximately 86° with the circumferential direction of the tyre.

LIST OF REFERENCE SIGNS

(Part of the Description)

[0034] 1 Tread [0035] 2 Belt [0036] 3 Carcass [0037] 3a Carcass upturned portion [0038] 4 Inner layer [0039] 5 Bead [0040] 6 Bead core [0041] 7 Bead core profile [0042] 8 Side wall [0043] 13 Belt bandage [0044] 31 First carcass ply [0045] 32 Second carcass ply [0046] 321, 322 Ply part of the second carcass ply [0047] rR Radial direction