Pneumatic vehicle tire having a tread

Abstract

Disclosed are pneumatic vehicle tires and methods of their production, the tires comprising a tread that has a tread segment arranged radially on the outside, and a material strip that is arranged helically in windings approximately in the circumferential direction, wherein, in the region of the tread segment, the material strip has at least two layers in the longitudinal direction of the material strip, wherein the first layer is formed from a first rubber compound and the second layer is formed from a second rubber compound, and wherein the layers connect the radially outer surface to the radially inner surface of the tread segment. The disclosed pneumatic vehicle tire has lower noise emissions and more uniform wear during driving and is improved in respect of at least one conflict of aims.

Claims

1. A pneumatic vehicle tire comprising a tread, wherein the tread comprises a tread segment that is arranged radially on the outside, wherein the tread segment comprises a material strip that is arranged helically in windings approximately in the circumferential direction, wherein, in the region of the tread segment, the material strip comprises at least a first layer and a second layer in the longitudinal direction of the material strip, wherein the first layer of the material strip is formed from a first rubber compound and the second layer of the material strip is formed from a second rubber compound that is different from the first rubber compound, wherein the first layer of the material strip and the second layer of the material strip connect the radially outer surface of the tread segment to the radially inner surface of the tread segment, wherein in the vulcanized state, the first rubber compound and the second rubber compound comprise approximately the same Shore A hardness, determined at room temperature in accordance with DIN ISO 7619-1, wherein in the vulcanized state, the first rubber compound and the second rubber compound differ in at least one additional physical property, and wherein the first rubber compound and the second rubber compound differ by at least 2% in the rebound resilience thereof, and wherein the rubber compound with the greater rebound resilience has a rebound resilience of 23% to 75% and the other rubber compound has a rebound resilience of 8% to 50%, in each case determined at room temperature in accordance with DIN 53512.

2. The pneumatic vehicle tire of claim 1, wherein the first rubber compound and the second rubber compound differ by at least 5% in the rebound resilience thereof, and wherein the rubber compound with the greater rebound resilience has a rebound resilience of 23% to 75% and the other rubber compound has a rebound resilience of 8% to 50%, in each case determined at room temperature in accordance with DIN 53512.

3. The pneumatic vehicle tire of claim 1, wherein the second rubber compound comprises a stress value, determined at 300% elongation at room temperature in accordance with DIN 53504, that is higher by at least 1.0 MPa than that of the first rubber compound.

4. The pneumatic vehicle tire of claim 1, wherein the second rubber compound comprises a stress value, determined at 300% elongation at room temperature in accordance with DIN 53504, that is higher by at least 1.5 MPa than that of the first rubber compound.

5. The pneumatic vehicle tire of claim 1, wherein the two rubber compounds each comprise a Shore A hardness of 48 Shore A to 75 Shore A.

6. The pneumatic vehicle tire of claim 1, wherein the two rubber compounds each comprise a Shore A hardness of 55 Shore A to 68 Shore A.

7. The pneumatic vehicle tire of claim 1, wherein within the tread segment the interface between the first layer of the material strip and the second layer of the material strip comprise a mean slope angle per winding of 80 to 80 to the radial direction rR of the pneumatic vehicle tire, wherein the ratio of the volume of the first layer of the material strip to the volume of the second layer of the material strip per winding is 1:1 to 10:1, wherein a mean cross-sectional thickness per winding of the first layer of the material strip is 0.5 mm to 5 mm, and/or wherein a mean cross-sectional thickness per winding of the second layer of the material strip is 0.5 mm to 5 mm.

8. The pneumatic vehicle tire of claim 1, wherein within the tread segment the interface between the first layer of the material strip and the second layer of the material strip comprises a mean slope angle per winding of 80 to 80 to the radial direction rR of the pneumatic vehicle tire, wherein the ratio of the volume of the first layer of the material strip to the volume of the second layer of the material strip per winding is 1:1 to 10:1, wherein a mean cross-sectional thickness per winding of the first layer of the material strip is 0.5 mm to 1 mm, and/or wherein a mean cross-sectional thickness per winding of the second layer of the material strip is 0.5 mm to 1 mm.

9. The pneumatic vehicle tire of claim 1, wherein the pneumatic vehicle tire comprises two shoulder regions, wherein in one or in both shoulder regions, the tread comprises a tread segment and, axially to the inside relative to the tread segment, a further segment, arranged radially on the outside of the tread, and wherein the volume density of the second rubber compound in the further segment is lower than the volume density of the second rubber compound in the tread segment.

10. The pneumatic vehicle tire of claim 9, wherein the volume density of the second rubber compound in the further segment is equal to 0.

11. The pneumatic vehicle tire of claim 1, wherein within the tread segment, the mean slope angle per winding that is enclosed by the interface between the first layer and the second layer of the material strip, and the radial direction rR, changes in the axial direction aR.

12. The pneumatic vehicle tire of claim 11, wherein the mean slope angle per winding increases in magnitude from axially on the inside to axially on the outside.

13. The pneumatic vehicle tire of claim 1, wherein the tread comprises two shoulder regions, each comprising one of the tread segments, wherein the tread segments comprise a mean slope angle per winding, and wherein the two tread segments differ in the sign of the mean slope angle thereof per winding that is enclosed by an interface between the first layer and the second layer of the respective material strip and the radial direction rR.

14. The pneumatic vehicle tire of claim 1, wherein the material strip comprises a third layer composed of a rubber compound different from the first rubber compound and the second rubber compound.

15. The pneumatic vehicle tire of claim 1, wherein the material strip extends over at least 80% of the axial width of the tread.

16. The pneumatic vehicle tire of claim 1, wherein the tire is a vehicle tire or a motorcycle tire, and wherein the tire is a winter tire.

17. A method for producing a pneumatic vehicle tire, which comprises: extruding by co-extrusion or cutting a calendered multi-compound web of at least two rubber compounds to produce a material strip; winding the material strip approximately helically in the circumferential direction of the pneumatic vehicle tire to form a tread segment arranged radially on the outside of the vehicle tire, wherein, in the region of the tread segment, the material strip comprises at least a first layer and a second layer in the longitudinal direction of the material strip, wherein the first layer of the material strip is formed from a first rubber compound and the second layer of the material strip is formed from a second rubber compound that is different from the first rubber compound, wherein the first layer of the material strip and the second layer of the material strip connect the radially outer surface of the tread segment to the radially inner surface of the tread segment, wherein in the vulcanized state, the first rubber compound and the second rubber compound comprise approximately the same Shore A hardness, determined at room temperature in accordance with DIN ISO 7619-1, wherein in the vulcanized state, the first rubber compound and the second rubber compound differ in at least one additional physical property, wherein the first rubber compound and the second rubber compound differ by at least 2% in the rebound resilience thereof, and wherein the rubber compound with the greater rebound resilience has a rebound resilience of 23% to 75% and the other rubber compound has a rebound resilience of 8% to 50%, in each case determined at room temperature in accordance with DIN 53512.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various embodiments disclosed herein will now be described with reference to the drawings wherein:

(2) FIG. 1 shows a partial cross section through the tread region of a pneumatic vehicle tire comprising one embodiment,

(3) FIG. 2 shows schematically an embodiment of the tread;

(4) FIG. 3 shows schematically an embodiment of the tread;

(5) FIG. 4 shows schematically an embodiment of the tread;

(6) FIG. 5 shows schematically an embodiment of the tread; and,

(7) FIG. 6 shows schematically an embodiment of the tread.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

(8) FIG. 1 shows schematically and by way of example a partial cross section of a motorcar tire. The customary constituent parts of the tire include, in particular, a tread 1, a belt structure 2 arranged radially on the inside of the tread 1 and comprising a plurality of belt plies and optionally a belt bandage, furthermore a radial carcass 3, a largely airtight inner liner 4 and side walls (not shown) as well as bead regions with bead cores, core profiles and further reinforcing plies possibly provided in the bead regions. The tread 1 is provided, in particular in a manner known per se, with profiling, which is not shown.

(9) The tread 1 extends beyond the width of the tire in the ground contact area and ends in the shoulder regions 5. At the shoulders, tread end regions consisting of the side wall compound can be provided.

(10) FIGS. 2 to 6 each show schematically an embodiment of the tread. The embodiments are suitable for a tread 1 of a motorcar tire of the kind illustrated in FIG. 1, in particular for a motorcar tire for use in winter driving conditions.

(11) The treads 1 illustrated in FIGS. 2 to 6 each have a tread segment 6 arranged radially on the outside, wherein the tread segment 6 has a material strip 7, which is arranged helically in windings approximately in the circumferential direction. In the region of the tread segment 6, the material strip 7 has at least two layers 8, 9 in the longitudinal direction thereof,

(12) wherein the first layer 8 is formed from a first rubber compound and the second layer 9 is formed from a second rubber compound different from the first compound,

(13) wherein the first layer 8 and the second layer 9 connect the radially outer surface 10 of the tread segment 6 to the radially inner surface 11 of the tread segment 6.

(14) The Shore A hardness of the first and second rubber compounds, determined at room temperature in accordance with DIN ISO 7619-1, are 48 Shore A to 75 Shore A, or 55 Shore A to 68 Shore A, and differ from one another by at most 1.5 Shore A, the DIN being herein incorporated by reference in its entirety for all purposes. In the vulcanized state, the first and second rubber compounds furthermore differ in at least one further physical property.

(15) In a first embodiment, each of the treads 1 shown in FIGS. 2 to 6 has a first and a second rubber compound, which differ by at least 2%, preferably by at least 5%, in the rebound resilience thereof, wherein the rubber compound with the greater rebound resilience has a rebound resilience of 23% to 75% and the wherein the other rubber compound has a rebound resilience of 8% to 50%, in each case determined at room temperature in accordance with DIN 53512, the DIN being herein incorporated by reference in its entirety for all purposes. Here, either the first rubber compound or the second rubber compound can be the rubber compound with the higher rebound resilience.

(16) In a second embodiment, each of the treads 1 shown in FIGS. 2 to 6 has a second rubber compound, the stress value of which, determined at 300% elongation at room temperature in accordance with DIN 53504, is higher by at least 1.0 MPa, or by at least 1.5 MPa, than that of the first rubber compound, the DIN being herein incorporated by reference in its entirety for all purposes.

(17) The treads 1 shown are produced at least partially by a procedure in which, to form the tread segment 6 arranged radially on the outside, a material strip 7 is wound on approximately helically in the circumferential direction of the pneumatic vehicle tire, wherein the material strip 7 comprises the first 8 and the second layer 9. In this case, the multilayer material strip 7 is extruded as a material strip, in particular, by co-extrusion, or is produced by cutting a calendered multi-compound web and joining together the pieces thereby obtained.

(18) FIG. 2 shows a tread 1 which is formed by a material strip 7 arranged helically in windings in the circumferential direction, wherein the material strip 7 is of two-layer configuration over the entire length thereof. The material strip 7 extends over the entire axial width of the tread 1, and the tread segment 6 extends substantially over the entire axial width of the tread 1.

(19) The interface 12 between the first layer 8 and the second layer 9 has a mean slope angle 13 per winding of 80 to 80 to the radial direction rR of the pneumatic vehicle tire. Furthermore, the ratio of the volume of the first layer 8 to the volume of the second layer 9 per winding is 1:1 to 10:1 and the mean cross-sectional thickness 14 per winding of the first layer 8 and/or the mean cross-sectional thickness 15 per winding of the second layer 9 is 0.5 mm to 1 mm.

(20) FIGS. 3 and 4 each show a tread 1, which has a tread segment 6 in both shoulder regions 5 and, axially to the inside relative to the tread segments 6, a further segment 16, arranged radially on the outside, of the tread 1, wherein the volume density of second rubber compound in the further segment 16 is lower than the volume density of second rubber compound in the tread segments 6.

(21) Here, the illustrative embodiment shown in FIG. 3 also has the second rubber compound in the further segment 16. In particular, segments 6 and 16 are formed from a single material strip 7, wherein the ratio of the volume of the first layer 8 of a winding to the volume of the second layer 9 of the winding of the material strip 7 changes in the axial direction.

(22) In the illustrative embodiment shown in FIG. 4, the volume density of second rubber compound in the further segment 16 is equal to 0. Layer 19 is thus formed from a rubber compound different from the first rubber compound. In particular, the further segment 16 has a material strip comprising electrically conductive material 17, wherein the electrically conductive material 17 connects the tread surface 18 in an electrically conductive manner to an electrically conductive component arranged radially to the inside of the material strip. In particular, segments 6 and 16 are formed from different material strips. However, segments 6 and 16 can also be formed from a material strip, the second layer of which is not formed from the second rubber compound in the region of segment 16 but from a rubber compound different therefrom, in particular from the first rubber compound and/or from electrically conductive material 17.

(23) FIGS. 5 and 6 each show a tread 1 having at least one tread segment 6, wherein, within the tread segment 6, the mean slope angle 13 per winding that is enclosed by the interface 12 between the first layer 8 and the second layer 9 of the material strip 7 and the radial direction changes in the axial direction. Moreover, the two shoulder regions differ at least in the sign of the mean slope angle 13 per winding that is enclosed by the interfaces 12 between the first layer 8 and the second layer 9 of the respective material strip 7 and the radial direction.

(24) Here, the tread 1 illustrated in FIG. 5 differs from the tread 1 illustrated in FIG. 4 essentially in that, within the tread segments 6 arranged in the shoulder regions 5, the mean slope angle 13 per winding increases in magnitude from axially on the inside to axially on the outside and in that the two tread segments 6 differ in the sign of the mean slope angle 13 thereof per winding that is enclosed by the interfaces 12 between the first layer 8 and the second layer 9 of the respective material strip 7 and the radial direction.

(25) In particular, the tread 1 illustrated in FIG. 6 is formed from a single material strip 7.

(26) The tread 1 illustrated in FIGS. 2 to 6 can form or partially form substantially the entire tread of a pneumatic vehicle tire or a radially outer region of the tread, in particular the cap layer.

(27) Tables 1 and 2 below contain examples of rubber compound compositions M11 and M21 for the first layer 8 and rubber compound compositions M12 and M22 for the second layer 9 of the compound strip 7. A compound strip 7 of this kind is suitable, in particular, as a compound strip 7 for the treads 1 illustrated in FIGS. 2 to 6. The quantity data are given in the unit phr (parts per hundred rubber) customary in rubber technology. In each case, the quantity data relate to the proportions by mass of the base polymer or, in the case of polymer blends, to those of the base polymers. Also given are the physical properties of Shore A hardness, determined at room temperature in accordance with DIN ISO 7619-1, and the stress value, determined at 300% elongation at room temperature in accordance with DIN 53504, and the rebound resilience, determined at room temperature in accordance with DIN 53512, the DINs being herein incorporated by reference in their entirety for all purposes.

(28) TABLE-US-00001 TABLE 1 Constituents Unit M1.sub.1 M1.sub.2 NR .sup.a) phr 4 5 BR .sup.b) phr 2 67 SBR .sup.c) phr 41.3 SBR .sup.d) phr 28 SBR .sup.e) phr 88 Silica .sup.f) phr 115 127 Carbon black N 399 phr 15 5 Plasticizer .sup.g) phr 35 58 Silane .sup.h) phr 15.5 Silane .sup.i) phr 9 Other additives .sup.j) phr 14.5 11 S and accelerator .sup.k) phr 6.8 5 Physical properties Shore A hardness Shore A 70 70 Stress value MPa 7.8 12.6 Rebound resilience % 13 35 Substances used .sup.a) Natural rubber TSR .sup.b) BR: BUNA CB 24, Lanxess .sup.c) SBR: Intol 1739, Eni .sup.d) SBR: Sprintan SLR 3402, Styron .sup.e) SBR: HP755B, JSR .sup.f) Silica Zeosil 1165 MP, Rhodia .sup.g) Plasticizer Vivatec C500, Thai Base Public Company Ltd. .sup.h) Silane NXT, Momentive .sup.i) Silane Si263, Evonik .sup.j) Other additives: antioxidant 6PPD, zinc oxide, stearic acid .sup.k) Sulfur and accelerator CBS

(29) TABLE-US-00002 TABLE 2 Constituents Unit M2.sub.1 M2.sub.2 NR .sup.a) phr 40 25 BR .sup.b) phr 30 SBR .sup.c) phr 41.25 SBR .sup.d) phr 75 Silica .sup.e) phr 78 82 Carbon black N 399 phr 5 5 Plasticizer .sup.f) phr 21 11 Silane .sup.g) phr 5.6 Silane .sup.h) phr 8.42 Other additives .sup.i) phr 11 11 S and accelerator .sup.j) phr 5.7 4.5 Physical properties Shore A hardness Shore A 68 68 Stress value MPa 7.4 13.4 Rebound resilience % 33 27 Substances used .sup.a) Natural rubber TSR .sup.b) BR: BUNA CB 24, Lanxess .sup.c) SBR: Buna VSL 5025-2, Lanxess .sup.d) SBR: Sprintan SLR 4602, Styron .sup.e) Silica Ultrasil VN3, Evonik .sup.f) Plasticizer Vivatec C500, Thai Base Public Company Ltd. .sup.g) Silane Si263, Evonik .sup.h) Silane NXT, Momentive .sup.i) Other additives: antioxidant 6PPD, zinc oxide, stearic acid .sup.j) Sulfur and accelerator CBS

(30) It is understood that the foregoing description is that of the preferred embodiments and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.

LIST OF REFERENCE SIGNS

Part of the Description

(31) 1 Tread 2 Belt structure 3 Radial carcass 4 Inner layer 5 Shoulder region 6 Tread segment 7 Material strip 8 First layer 9 Second layer 10 Radially outer surface of the tread segment 11 Radially inner surface of the tread segment 12 Interface 13 Slope angle 14 Mean cross-sectional thickness of the first layer 15 Mean cross-sectional thickness of the second layer 16 Further segment of the tread 17 Electrically conductive material 18 Tread surface 19 Layer rR Radial direction aR Axial direction