Pneumatic Vehicle Tires Comprising a Belt Bandage

Abstract

Pneumatic vehicle tyres which have a bandage ply (8) comprising two lateral portions (10) and a center portion (12) in the axial extension, wherein each lateral portion (10) has at least one hybrid reinforcement, and wherein the center portion (12) has at least one reinforcement which has a lower modulus of elasticity than the hybrid reinforcements of the lateral portions (10), in each case measured as per ASTM D885M at an elongation of 3%. It is the object of the invention to provide a tyre with reduced rolling resistance and good high-speed characteristics with reliable producibility. This is achieved in that the hybrid reinforcement is a hybrid cord made of at least one low-modulus thread and one high-modulus thread twisted together, and in that the hybrid reinforcement has a fineness of at most 550 dtex, preferably at most 500 dtex, particularly preferably at most 460 dtex, and in that the reinforcement of the center portion (12) has a fineness of at most 1100 dtex, preferably at most 600 dtex, particularly preferably at most 500 dtex.

Claims

1.-10. (canceled)

11. A pneumatic vehicle tire comprising a carcass, a profiled tread, a belt and a single or multi-ply belt bandage having strength members running in the circumferential direction of the tire which covers this belt; wherein at least one bandage ply of the belt bandage comprises in its axial extent two lateral sections, each comprising an axial edge of the bandage ply, and a central section arranged between the two lateral sections; wherein each of the two lateral sections comprises at least one hybrid strength member; wherein the central section comprises at least one strength member having a lower modulus of elasticity than the hybrid strength members of the two lateral sections, the modulus of elasticity measured as per ASTM D885M at an extension of 3%; wherein the at least one hybrid strength member of each the two lateral sections is a hybrid cord made of at least two yarns twisted together, and wherein at least a first yarn is a high-modulus yarn and wherein a further yarn is a low-modulus yarn; wherein the at least one hybrid strength member of each of the two lateral sections have a fineness of not more than 550 dtex; and, wherein the at least one strength member of the central section has a fineness of not more than 1100 dtex.

12. The pneumatic vehicle tire as claimed in claim 11, wherein the breaking extension of the hybrid strength members of the two lateral sections is in a range from 4% to 7%.

13. The pneumatic vehicle tire as claimed in claim 12, wherein the breaking extension of the hybrid strength members of the two lateral sections is in a range from 5% to 6%.

14. The pneumatic vehicle tire as claimed in claim 11, wherein the breaking extension of the strength member in the central section is at least 7%, preferably at least 8%.

15. The pneumatic vehicle tire as claimed in claim 14, wherein the breaking extension of the strength member in the central section is at at least 8%.

16. The pneumatic vehicle tire as claimed in claim 12, wherein the high-modulus yarn comprises aramid fibers, carbon fibers, glass fibers or basalt.

17. The pneumatic vehicle tire as claimed in claim 12, wherein the low-modulus yarn the low-modulus yarn comprises a polyamide 6.6, polyamide 10.10, or a polyester.

18. The pneumatic vehicle tire as claimed in claim 17, wherein the low-modulus yarn the low-modulus yarn comprises a polyethylene terephthalate (PET).

19. The pneumatic vehicle tire as claimed in claim 12, wherein individual yarns of the hybrid cords of the two lateral sections have a fineness of not more than 320 dtex.

20. The pneumatic vehicle tire as claimed in claim 12, wherein individual yarns of the hybrid cords of the two lateral sections have a fineness of not more than 240 dtex.

21. The pneumatic vehicle tire as claimed in claim 11, wherein the strength member of the central section is a yarn or a cord.

22. The pneumatic vehicle tire as claimed in claim 11, wherein the strength member of the central section comprises a polyamide 6.6, polyamide 10.10, or a polyester.

23. The pneumatic vehicle tire as claimed in claim 22, wherein the strength member of the central section comprises a polyethylene terephthalate (PET).

24. The pneumatic vehicle tire as claimed in claim 11, wherein the two lateral sections, on an axial side of the pneumatic vehicle tire, cover at least a belt edge of the radially outermost belt ply of the belt.

25. The pneumatic vehicle tire as claimed in claim 11, wherein the two lateral sections, on an axial side of the pneumatic vehicle tire, cover at least an axially outermost belt edge of the belt.

26. The pneumatic vehicle tire as claimed in claim 11, wherein the at least one hybrid strength member of each of the two lateral sections have a fineness of not more than 500 dtex.

27. The pneumatic vehicle tire as claimed in claim 26, wherein the at least one hybrid strength member of each of the two lateral sections have a fineness of not more than 460 dtex.

28. The pneumatic vehicle tire as claimed in claim 11, wherein the at least one strength member of the central section has a fineness of not more than 600 dtex.

29. The pneumatic vehicle tire as claimed in claim 28, wherein the at least one strength member of the central section has a fineness of not more than 500 dtex.

30. The pneumatic vehicle tire as claimed in claim 1, wherein pneumatic vehicle tire is a tire for passenger cars.

Description

[0031] Further features, advantages and particulars of the invention are now elucidated in more detail having reference to the schematic drawings which depict working examples.

[0032] FIG. 1 shows a radial cross section through a pneumatic vehicle tire according to the invention;

[0033] FIG. 2 shows a force-extension curve of strength member cords suitable in the context of the invention.

[0034] FIG. 1 shows a radial cross section through a pneumatic vehicle tire for a passenger car. The essential components from which the depicted pneumatic vehicle tire is composed are a largely air-impermeable inner layer 1, a carcass 2 which conventionally reaches from the region of the crown of the pneumatic vehicle tire over the sidewalls 3 into the bead regions 4 and is anchored there by wrapping around high-tensile bead cores 5, a profiled tread 6 located radially outside the carcass and a belt 7 arranged between the tread 6 and the carcass 2 and comprising two strength member plies which is radially covered on the outside with the belt bandage which comprises a bandage ply 8. The bandage ply covers the belt edges 9 and comprises strength members wound along the axial width in parallel in the circumferential direction of the pneumatic vehicle tire.

[0035] The bandage ply 8 comprises in its axial extent two lateral sections 10, each comprising an axial edge 11 of the bandage ply 8, and a central section 12 arranged between the two lateral sections 10. Each of the two lateral section 10 covers on its axial side of the tire at least the belt edge 9 of the radially outermost belt ply and the axially outermost belt edge 9 of the belt 7.

[0036] The strength members of the two lateral sections 10 are hybrid cords made of a high-modulus yarn and a low-modulus yarn and have a cord fineness of not more than 550 dtex, preferably of not more than 500 dtex, particularly preferably of not more than 460 dtex. The breaking extension of the hybrid cords is 5% to 6%. The strength member(s) of the central section 12 are cords of two low-modulus yarns twisted together and have a lower modulus of elasticity than the hybrid cords of the lateral sections 10, in each case measured as per ASTM D885M at an extension of 3%. Furthermore, the cord fineness is not more than 1100 dtex, preferably not more than 600 dtex, particularly preferably not more than 500 dtex. The breaking extension is at least 7%. The strength members of the belt bandage ply 8 have been provided with an RFL dip and stretched with application of heat.

[0037] In one embodiment of the invention the high-modulus yarn of the hybrid cords of the lateral sections 10 is an aramid yarn having a fineness of 220 dtex and the low-modulus yarn is either a PA 6.6 yarn having a fineness of 235 dtex or a PET yarn having a fineness of 238 dtex. The strength member(s) of the central section 12 are formed from two twisted-together yarns of PA 6.6 having a fineness of 470 dtex or less or of two twisted-together yarns of PET having a fineness of 550 dtex or less.

[0038] FIG. 2 shows force-extension curves, determined as per ASTM D885, of dipped hybrid cords for use in the lateral regions of the belt bandage of a pneumatic vehicle tire as shown in FIG. 1. “Dipped” is to be understood as meaning that: after twisting the cord has been impregnated in a manner known to those skilled in the art with a dip solution, thus providing it with a rubber-friendly finish, and stretched with application of heat. The horizontal axis shows extension D, the vertical axis force F.

[0039] Force-extension curves of the two above-described hybrid cords having the constructions aramid 220x1+PA 6.6 235x1 and aramid 220x1+PET 238x1 are depicted. It is apparent that both hybrid cords have a breaking extension of 5% to 6%. This ensures sufficient expansion in the lateral regions during tire construction.

[0040] It is furthermore apparent that the central cords have a lower modulus of elasticity at 3% expansion than the hybrid cords of the lateral sections. The use of high-modulus aramid material in the lateral regions ensures good absorption of the forces arising there, in particular in high-speed use, while in the central region the pneumatic vehicle tire develops a round contour as a result of the lower-modulus PA6.6 or PET and thus exhibits positive high-speed properties.

LIST OF REFERENCE NUMERALS

[0041] (Part of the Description)

[0042] 1 inner layer

[0043] 2 carcass

[0044] 3 sidewall

[0045] 4 bead region

[0046] 5 bead core

[0047] 6 tread

[0048] 7 belt

[0049] 8 bandage ply

[0050] 9 belt edge

[0051] 10 lateral section

[0052] 11 axial edge of bandage ply

[0053] 12 central section

[0054] aR axial direction

[0055] rR radial direction