Pneumatic vehicle tyre and method for producing a pneumatic vehicle tyre

Abstract

The invention relates to a pneumatic vehicle tyre with a tread (1), which has a width (b1) and comprises a central tread part (7a, 8a) of a first rubber material, extending over part of the width (b1) of the tread (1), and comprises a tread part (7b, 8b) of a second rubber material, adjoining the central part, forming lateral portions of the tread outer surface and extending right across the entire width (b1) of the tread (1), wherein the first rubber material has a Shore A hardness according to DIN ISO 7619-1 that is greater than the Shore A hardness of the second rubber material. The tread part (7b, 8b) extending across the entire width (b1) of the tread (1) covers the central tread part (7a, 8a) radially on the outside and forms the complete tread outer surface.

Description

[0001] Description

[0002] Pneumatic vehicle tire and method for producing a pneumatic vehicle tire

[0003] The invention relates to a pneumatic vehicle tire with a tread having a width with a central tread part made of a first rubber material running over part of the width of the tread and a tread part made of a second rubber material adjoining said central tread part, forming lateral sections of the tread outer surface and running continuously over the entire width of the tread, wherein the first rubber material has a Shore A hardness according to DIN ISO 7619-1 which is greater than the Shore A hardness of the second rubber material.

[0004] The invention further relates to a method for producing such a pneumatic vehicle tire.

[0005] A pneumatic vehicle tire of the type mentioned above, which is a motorcycle tire, is known, for example, from WO 01 / 39998 A1. The motorcycle tire has a tread with a central tread part and a tread part that runs continuously across the entire width of the tread. The central tread part is "inserted" into the tread part that runs continuously across the entire width of the tread, so that the continuous tread part runs radially inside the central tread part. The rubber material of the central tread part has a Shore A hardness at 100°C of at least 50 ShA (Shore A). The rubber material of the tread part that runs continuously across the entire width of the tread has a Shore A hardness at 100°C of 40 ShA to 49 ShA.

[0006] The invention is based on the object of designing a pneumatic vehicle tire of the type mentioned above in such a way that its tread is particularly well-balanced in terms of its grip properties when new, while maintaining good ride comfort and handling characteristics. Furthermore, a method for producing such a pneumatic vehicle tire is to be provided, which allows for the production of tread parts with a variable cross-sectional shape.

[0007] As far as the pneumatic vehicle tire is concerned, the stated object is achieved according to the invention in that the tread part running over the entire width of the tread covers the central tread part radially outward and forms the complete tread outer surface.

[0008] As far as the method is concerned, the stated problem is solved in that the central tread part is formed by winding an extruded rubber mixture once and the tread part running across the entire width of the tread is formed by winding an extruded rubber mixture strip several times in a spiral and overlapping manner.

[0009] The pneumatic vehicle tire offers particularly advantageous grip and handling characteristics thanks to the softer tread section running continuously across the outer surface. The harder, central tread section located radially within this tread section ensures good driving comfort.

[0010] The method according to the invention makes it possible to easily modify the tread parts with regard to their cross-sectional shape, so that a tire with the desired grip and handling behavior can be produced in a particularly efficient manner.

[0011] According to a preferred embodiment, the Shore A hardness of the rubber material of the tread section running across the entire width of the tread is 50.0 ShA to 65.0 ShA, in particular 55.0 ShA to 63.0 ShA. This measure is particularly advantageous for optimal driving comfort. A further preferred embodiment is characterized in that the Shore A hardness of the rubber material of the central tread section is 3.0 ShA to 25.0 ShA, in particular by up to 20.0 ShA, preferably by up to 15.0 ShA, particularly preferably by 8.0 ShA to 12.0 ShA, greater than the Shore A hardness of the rubber material of the tread section running across the entire width of the tread. This measure ensures advantageous stabilization of the softer tread section with regard to grip and handling properties.

[0012] Furthermore, it is preferred if the Shore A hardness of the rubber material of the central tread portion is at most 75.0 ShA. This measure contributes in particular to maintaining good ride comfort as the tread wear progresses.

[0013] In a further preferred embodiment, the central tread portion has a width of 30% to 85%, in particular 40% to 75%, of the tread width. This ensures that, even with progressive tread wear, the softer rubber material of the tread portion, which runs across the entire width of the tread in a new tire, is retained in correspondingly wide lateral sections of the tread. This contributes to maintaining good handling characteristics when cornering despite tread wear.

[0014] Preferably, the central tread part, viewed in cross-section, is designed symmetrically with respect to the tire equatorial plane.

[0015] According to a further preferred embodiment, the central tread portion, viewed in cross-section, has a thickness in the radial direction at its thickest point that amounts to 50% to 90%, in particular 60% to 85%, of the thickness of the tread measured in the radial direction at the tire's equatorial plane. This measure contributes to good driving comfort with a new tire. In the latter embodiment, it is advantageous if the central tread portion has its thickest point at least in the tire's equatorial plane.

[0016] A further preferred embodiment is characterized in that the central tread part, viewed in cross-section, is circular segment-shaped and tapers off in the direction of the tread shoulders.

[0017] In an alternative and likewise preferred embodiment, the central tread portion, viewed in cross-section, has a central portion with an axial width of 15% to 30% of the width of the central tread portion, and two side portions that are thinner than the central portion and have end sections tapering toward the tread shoulders. A central tread portion designed in this way allows for fine adjustment with regard to grip, ride comfort, and handling characteristics.

[0018] Preferably, the pneumatic vehicle tire is a pneumatic vehicle tire for a single-track motor vehicle.

[0019] The pneumatic vehicle tire is particularly preferably a motorcycle tire. In particular, a motorcycle tire ensures particularly good ride comfort as well as particularly good grip and handling characteristics when cornering, even with advanced tread wear.

[0020] A further preferred embodiment is characterized in that the central tread section is made of an extruded rubber compound, and the tread section running across the entire width of the tread is made of an extruded, multi-spiral, overlapping rubber compound strip. With a tire constructed in this way, the tread can be particularly easily adapted during production, making it particularly easy to configure the tire with regard to the desired grip, ride comfort, and handling characteristics.

[0021] Further features, advantages and details of the invention will now be explained in more detail with reference to the drawing, which schematically shows exemplary embodiments of the invention.

[0022] Fig. 1 shows a cross section through a motorcycle tire with a first embodiment of the invention and

[0023] Fig. 2 shows a cross section through a motorcycle tire with a second embodiment of the invention.

[0024] Pneumatic vehicle tires designed according to the invention are tires for motor vehicles, in particular for single-track motor vehicles, preferably for motorcycles, or for multi-track motor vehicles, in particular for passenger cars, vans or light trucks (small vans with a GVW < 3.5 t, light trucks with a GVW < 7.5 t).

[0025] Fig. 1 and Fig. 2 each show a cross-section through a radial-ply pneumatic vehicle tire for a motorcycle. The pneumatic vehicle tire has a tread 1, two sidewalls 2, a belt 3, an inner layer 4, a carcass ply 5, and bead regions 6, each with a bead core 6a and a bead filler 6b. The tire's equatorial plane is indicated by a line AA.

[0026] The belt 3 is designed in one or two layers, each layer consisting of strength members embedded in a belt rubber coating and running parallel to one another, for example made of steel or textile cords of known construction.

[0027] The carcass ply 5 extends between the belt 3 and the inner layer 4, as well as between the sidewalls 2 and the inner layer 4, and is folded around the bead cores 6a, forming carcass turnups 5a. The carcass ply 5 consists of a carcass rubber lining and reinforcements embedded therein, which are also, in particular, steel or textile cords of known construction.

[0028] The tread 1 is provided with a profile (not shown), for example, implemented in a known manner. Viewed in cross-section, it has a thickness di measured in the tire equatorial plane, in the radial direction, and a width bi measured perpendicular to the tire equatorial plane. The thickness di is measured between the belt 3 and the tread periphery. The tread periphery is defined by an envelope containing the tread outer surface. The width bi is measured between the furthest apart points of the tread 1.

[0029] In the embodiments shown in Fig. 1 and Fig. 2, the tread 1 is composed of a central tread part 7a (Fig. 1), 8a (Fig. 2) running over part of the width bi and a tread part 7b (Fig. 1), 8b (Fig. 2) running continuously over the entire width bi. The tread part 7b, 8b borders laterally on the central tread part 7a, 8a, covers the central tread part 7a, 8a radially outwardly and forms the complete tread outer surface of a new tire.

[0030] In the embodiment according to Fig. 1, the central tread part 7a, viewed in cross-section, has a width b2 determined perpendicular to the tire equatorial plane of 30% to 85%, in particular of 35% to 45%, of the width bi of the tread 1 and a thickness d2 determined in the tire equatorial plane, in the radial direction, of 50% to 90%, in particular of 60% to 85%, of the thickness di of the tread 1 and is designed in the shape of a circular segment, so that it tapers off in the direction of the tread shoulders.

[0031] In the embodiment shown in Fig. 2, the central tread part 8a, viewed in cross-section, has a width b3 determined perpendicular to the tire equatorial plane of 50% to 85%, in particular 60% to 70%, of the width bi of the tread 1 and a thickness ds determined in the tire equatorial plane, in the radial direction, of 50% to 90%, in particular 60% to 85%, of the thickness di, wherein the central tread part 8a has a center part 8a' and two side parts 8a" which are thinner than the center part, each with an end section (not numbered) tapering towards the tread shoulder. The center part 8a' has, viewed in cross-section, a width bs' relative to the radially outer surface of the side parts 8a" of 15% to 30% of the width bs.

[0032] The tread part 7b, 8b consists of a rubber material with a Shore A hardness according to DIN ISO 7619-1 of 50.0 ShA to 65.0 ShA, in particular of 55.0 ShA to 63.0 ShA.

[0033] The central tread part 7a, 8a consists of a rubber material with a Shore A hardness according to DIN ISO 7619-1, which is 3.0 ShA to 25.0 ShA, in particular up to 20.0 ShA, preferably up to 15.0 ShA, particularly preferably 8.0 ShA to 12.0 ShA, greater than the Shore A hardness of the rubber material of the tread part 7b, 8b.

[0034] Furthermore, it is preferred if the rubber materials of the tread parts 7a, 7b, 8a, 8b are matched to one another in such a way that the Shore A hardness of the rubber material of the central tread part 7a, 8a is at most 75.0 ShA.

[0035] The central tread portion 7a, 8a is produced in a correspondingly profiled form from an extruded rubber compound, which is applied to the built-up tire carcass or belt during tire production. The tread portion 7b, 8b is produced from an extruded rubber compound strip, which, after the extruded rubber compound forming the central tread portion 7a, 8b has been applied, is wound several times in a spiral and partially overlapping manner (strip winding). The invention is not limited to the described embodiments.

[0036] In particular, the tire can also be a tire for a car, a van or a light truck.

[0037] List of reference symbols

[0038] 1 tread

[0039] 2 side wall

[0040] 3 belts

[0041] 4 inner layer

[0042] 5 Carcass ply

[0043] 5a Carcass roll-up

[0044] 6 Bead area

[0045] 6a Bead core

[0046] 6b Core rider

[0047] 7a central tread section

[0048] 7b Tread section

[0049] 8a central tread section

[0050] 8a' middle section

[0051] 8a" side panel

[0052] 8b Tread section

[0053] AA line (tire equatorial plane) bi, b2, bs, bs'... Width di , d2, ds Thickness

Claims

Patent claims 1. Vehicle pneumatic tire with a tread (1) having a width (bi) and a central tread section (7a, 8a) made of a first rubber material extending over a part of the width (bi) of the tread (1) and a tread section (7b, 8b) made of a second rubber material extending continuously over the entire width (bi) of the tread (1) adjacent to the central tread section and forming lateral sections of the outer surface of the tread, wherein the first rubber material has a Shore A hardness according to DIN ISO 7619-1 which is greater than the Shore A hardness of the second rubber material, characterized in that the tread section (7b, 8b) extending over the entire width (bi) of the tread (1) radially covers the central tread section (7a, 8a) and forms the entire outer surface of the tread.

2. Vehicle pneumatic tire according to claim 1, characterized in that the Shore A hardness of the rubber material of the tread section (7b, 8b) extending over the entire width (bi) of the tread (1) is 50.0 ShA to 65.0 ShA, in particular 55.0 ShA to 63.0 ShA.

3. Vehicle pneumatic tire according to claim 1 or 2, characterized in that the Shore A hardness of the rubber material of the central tread part (7a, 8a) is greater by 3.0 ShA to 25.0 ShA, in particular by up to 20.0 ShA, preferably by up to 15.0 ShA, particularly preferably by 8.0 ShA to 12.0 ShA, than the Shore A hardness of the rubber material of the tread part (7b, 8b) extending over the entire width (bi) of the tread (1).

4. Vehicle pneumatic tire according to one of claims 1 to 3, characterized in that the Shore A hardness of the rubber material of the central tread part (7a, 8a) is at most 75.0 ShA.

5. Vehicle pneumatic tire according to one of claims 1 to 4, characterized in that the central tread section (7a, 8a) has a width (b2, bs) of 30% to 85%, in particular of 40% to 75%, of the width (bi) of the tread (1 ).

6. Vehicle pneumatic tire according to one of claims 1 to 5, characterized in that the central tread section (7a, 8a), viewed in cross-section, is symmetrical with respect to the tire equatorial plane (line AA).

7. Vehicle pneumatic tire according to one of claims 1 to 6, characterized in that the central tread section (7a, 8a), viewed in cross-section, has a thickness (d2, ds) in the radial direction at its thickest point which is 50% to 90%, in particular 60% to 85%, of the thickness (di) of the tread (1) determined in the radial direction at the tire equatorial plane (line AA).

8. Vehicle pneumatic tire according to claim 7, characterized in that the central tread section (7a, 8a) has its thickest point at least in the tire equatorial plane (line AA).

9. Vehicle pneumatic tire according to one of claims 1 to 8, characterized in that the central tread part (7a), viewed in cross-section, is designed in the shape of a circular segment and extends towards the tread shoulders.

10. Vehicle pneumatic tire according to one of claims 5 to 8, characterized in that the central tread section (8a), viewed in cross-section, has a central section (8a') with a width (bs') determined in the axial direction of 15% to 30% of the width (bs) of the central tread section (8a) and two side sections (8a") that are thinner than this, with end sections extending towards the tread shoulders.

11. Vehicle pneumatic tire according to one of claims 1 to 10, wherein a vehicle pneumatic tire for a single-track motor vehicle is.

12. Vehicle pneumatic tire according to claim 11, which is a motorcycle tire.

13. Vehicle pneumatic tire according to one of claims 1 to 12, characterized in that the central tread part (7a, 8a) is made of an extruded rubber compound and the tread part (7b, 8b) extending over the entire width (bi) of the tread (1) is made of an extruded rubber compound strip wound multiple times in a spiral and overlapping manner.

14. Method for manufacturing a vehicle pneumatic tire with a tread (1) having a width (bi) and a central tread section (7a, 8a) made of a first rubber material extending over a part of the width (bi) of the tread (1), and a tread section (7b, 8b) made of a second rubber material extending continuously over the entire width (bi) of the tread (1) adjacent to the central tread section, forming lateral sections of the outer surface of the tread, wherein the first rubber material has a Shore A hardness according to DIN ISO 7619-1, which is greater than the Shore A hardness of the second rubber material, characterized in that the central tread section (7a, 8a) is formed by a single winding of an extruded rubber compound and the tread section (7b, 8b) extending over the entire width (bi) of the tread (1) is formed by multiple spiral and overlapping windings of an extruded rubber compound strip.

Images