Tread profile of a vehicle tyre

Abstract

The tread profile has a profile tape whose fine incisions (2) are rotated over periphery of a tread, to divide tape into profile band portions. An omega-shaped geometry is arranged in axial direction and is spaced from axial portions (5,6). A central protrusion (7) is arranged between the axial portions and is set with a maximum expansion (b) in circumferential direction. The central protrusion is engaged into a corresponding recess of the profile band portions so that undercut is formed for coupling the profile band portions with one another in circumferential direction.

Description

[0001] The invention relates to a tread profile of a vehicle tire, which has a profile band circumferential around the circumference of the tread with fine incisions that divide the profile band into profile band sections, wherein the fine incision – in plan view – has an approximately Ω-shaped geometry consisting of two axially arranged sections spaced apart from each other at a distance a and a central protrusion arranged between these sections, oriented approximately circumferentially, with a maximum axial extent b, wherein the protrusion engages in a corresponding recess of the adjacent profile band section, wherein a < b, so that undercuts are formed by which these two profile band sections are coupled to each other circumferentially, and wherein the fine incision extends from a residual depth of the fine incision of 3 mm to 0.4 times the fine cutting depth exhibits a modified geometry, in that the undercutting-forming protrusion is only formed up to this residual depth.

[0002] Fine cuts, for example in commercial vehicle tires, serve to break up the water film on wet roads in order to achieve better wet performance of this tread.

[0003] A tread profile according to the general term is known from both FR 2 921 586 A1 and JP 11 151914 A.

[0004] GB 742,821 A discloses a tread profile consisting of circumferential profile bands. Each profile band is laterally bounded by a circumferential groove. The profile bands have Ω-shaped fine cuts that extend completely through the profile band in the axial direction and from the tread periphery radially inwards. This design of the fine cuts causes the profile band sections to be coupled or interlocked in the circumferential direction, resulting in so-called "interlocking" effects. Furthermore, good wet performance can be achieved on high-µ road surfaces. Tread profiles with Ω-shaped fine cuts are also known from WO 2009 / 077808 A1 and EP 1 195 271 A2.

[0005] This interlocking is particularly advantageous when the tread pattern is new, as the tread depth is high and the tread sections have a high degree of flexibility. The interlocking results in a beneficial stiffening of the tread strip under circumferential forces.

[0006] When the tread pattern has been driven on, the tread bands are inherently stiffer than when new due to the reduced remaining tread depth. Further stiffening through articulation is then disadvantageous.

[0007] The object of the invention is to provide a tread pattern for a vehicle tire that exhibits good handling as well as good wet performance throughout its service life.

[0008] The problem is solved by arranging the protrusion in the circumferential direction at a distance from the axial sections (in plan view) and by connecting the protrusion to the central ends of the axial sections by circumferential sections arranged approximately in the circumferential direction.

[0009] According to the invention, a tread profile is created which, in its new state—viewed from above a fine cut—causes interlocking effects between adjacent profile strip sections in the circumferential direction due to an approximately Ω-shaped geometry and exhibits good wet performance on high-µ surfaces. This is because the approximately Ω-shaped geometry of the fine cut allows the resulting undercuts to cause the profile strip sections to interlock under circumferential forces, leading to the advantageous stiffening of the profile strip. As the tread depth increases, the geometry of the fine cut differs from that of a new tread. Over this depth, the interlocking geometry of the fine cut under circumferential forces is abruptly reduced or eliminated by a change in the fine cut geometry, thus adapting to the higher stiffness of the tread profile further along.According to the invention, a connected system of fine incisions is formed, which together form gripping edges, but at the same time interlock with each other.

[0010] It is a tread pattern with a so-called "3D fine cut" that offers good handling as well as good wet performance throughout its lifespan.

[0011] "Axial direction" refers to the direction along the tire axis. "Circular direction" refers to the direction along the tire's rolling motion. "Radial direction" refers to the direction from the tire's center to the tread. "Cut point" refers to the line of a sipe closest to the tire's center. "Sip width" refers to the minimum circumferential extent of a sipe. "Tread depth" or "Sip depth" refers to the maximum radial difference between elements of a tread pattern or sipe.

[0012] The two axial sections, which appear as straight lines when viewed from above, are advantageously arranged on a common straight line.

[0013] It is advantageous if the circumferential sections – viewed from above – are formed as straight lines. The resulting edge in the circumferential direction is maximally dimensionally stable.

[0014] Further on page 3, line 30 of the originally submitted documents, the line runs from the base of the axial sections to the base and is formed as a straight line. This results in a continuous transition in the edge formation.

[0015] In another embodiment, the depth profile of the circumferential section is designed such that the base of these circumferential sections extends from the protrusion at the level of the residual depth to the base of the axial sections and is convex, with the convex curvature preferably pointing radially outwards. This profile reduces the stresses in the surrounding rubber under externally acting forces.

[0016] Such a tread pattern is to be used in a vehicle tire, preferably a commercial vehicle tire.

[0017] Further features, advantages, and details of the invention are described in more detail with reference to the drawings, which depict schematic embodiments. The drawings show... Fig. 1 a three-dimensional view of a tread profile of a vehicle tire with fine incisions in the tread bands; Fig. 2 a three-dimensional representation of a fine section of the tread profile ( Fig. 2a ) and in the state after reaching the residual depth with altered geometry ( Fig. 2b ); Fig. 3 a three-dimensional representation of a further fine incision; Fig. 4 a three-dimensional representation of yet another fine incision.

[0018] The Fig. 1 Figure 1 shows a three-dimensional view of a tread profile 1 of a vehicle tire with fine cuts 2 in the tread bands 3. Each tread band 3 is bounded on both sides by circumferential grooves 4. The fine cut 2 completely traverses the tread band 3 in the axial direction aR. Viewed from above, the fine cut 2 has an approximately Ω-shaped geometry consisting of two axial sections 5, 6 arranged approximately in the axial direction aR on a common imaginary line and spaced apart by a distance a, and a central protrusion 12 arranged between these sections 5, 6, oriented approximately in the circumferential direction uR, with a maximum axial extent b. The protrusion 12 is spaced circumferentially uR from the axial sections 5, 6. The protrusion 12 is connected to the central ends of the axial sections 5, 6 by circumferential sections 11, 12 arranged approximately in the circumferential direction uR.The protrusion 12 engages in a corresponding recess of the adjacent profile strip section 13. Here, a > b, so that undercuts 15 are formed, through which these two profile strip sections 13, 14 are coupled to each other in the circumferential direction uR and exhibit interlocking effects. In the new state of the tread profile, the fine groove 2 is a fine groove 2 formed continuously in the axial direction aR without any openings or interruptions. From a residual depth of the fine groove 2, which begins in the range of a depth of 3 mm to 0.4 times the fine groove depth, the geometry of the fine groove 2 is altered, in that the protrusion 12 forming the undercuts 15 is only formed up to this residual depth, see . Fig. 2, 3, 4 .

[0019] The Fig. 2 shows a three-dimensional representation of a fine section 2 of the tread profile ( Fig. 2a ) and this fine cut 2 in the state at the reached residual depth with altered geometry ( Fig. 2b The fine cut 2, when new, has the following features: Fig. 1 The geometry described is as follows. From a residual depth of the fine cut, which begins in the range of 3 mm to 0.4 times the fine cut depth, the fine cut 2 exhibits a modified geometry. The protrusion 7 is only present up to this residual depth and disappears beyond it. From this residual depth, only the two axially oriented sections 5, 6 retain their geometry up to their base 13, while the two circumferential sections 11, 12 become shorter over the further depth progression until they terminate at the base 13 at the axial sections 5, 6. This depth progression of the circumferential sections 11, 12 is such that the base 14 of these circumferential sections runs as a straight line from the protrusion 17 at the level of the residual depth to the base 13 of the axial sections.

[0020] The Fig. 3 Figure 1 shows a three-dimensional representation of a further fine incision 2. This further fine incision 2 differs from the fine incision 2 of the Fig. 2 , that the base 14 of the circumferential sections is convex and the convex shape points radially upwards.

[0021] The Fig. 4 shows a three-dimensional representation of yet another fine incision 2. This fine incision 2 has the geometry of the fine incision 2 of the Fig. 2 However, it differs in that the axial sections 5, 6 have a round or oval cavity 16 at their radially inner end, which terminates in the cross-section of the fine groove 2. The cavity, still viewed in the cross-section of the fine groove, has a height c of 0.5 to 4.0 mm measured in the radial direction of the tread profile and a width d of 0.5 to 4.0 mm measured in the circumferential direction of the tread profile. Bezugszeichenliste (Part of the description)

[0022] 1. Tread profile 2. Fine cut 3. Profile band 4. Circumferential groove 5. Axial section 6. Axial section 7. Protrusion 8. Profile band section 9. Profile band section 10. Undercut 11. Circumferential section 12. Circumferential section 13. Base of axial section 14. Base of circumferential section 15. Residual depth 16. Cavity aaxial distance between the sections bmaximum extent of the protrusion in the axial direction cheight of the cavity dwidth of the cavity rRradial direction aRaxial direction uRcircular direction

Claims

1. Tread profile (1) of a vehicle tire, which tread profile has a profile band (3) which runs in encircling fashion over the circumference of the tread and which has sipes (2) which divides the profile band (3) into profile band sections (8, 9) and wherein the sipe (2) has - in plan view - an approximately Ω-shape geometry composed of two axial sections (5 6), which are arranged approximately in an axial direction and which are spaced apart from one another by a spacing a, and of a central bulge (7) which is oriented approximately in a circumferential direction and which has a maximum extent b measured in the axial direction, wherein the bulge (7) engages into a corresponding recess of the adjacent profile band section (8, 9), wherein a < b, such that undercuts (10) are formed by way of which said two profile band sections (8, 9) are coupled to one another in the circumferential direction, and wherein the sipe (2), proceeding from a residual depth (15) of the sipe of 3 mm to 0.4 x the sipe depth, has a changed geometry by virtue of the bulge (7) which forms undercuts (10) being formed only as far as said residual depth (15), characterized in that - in plan view - the bulge (7) is arranged spaced apart in the circumferential direction uR from the axial sections (5, 6), and in that the bulge (7) is connected to the central ends of the axial sections by circumferential sections (11, 12) arranged approximately in the circumferential direction uR.

2. Tread profile according to Claim 1, characterized in that the circumferential sections (11, 12) - as seen in plan view - are in the form of straight lines.

3. Tread profile according to Claim 1 or 2, characterized in that the depth profile of the circumferential section (11, 12) is configured such that the base (14) of said circumferential sections (11, 12) runs proceeding from the bulge (17) at the level of the residual depth (15) as far as the sipe base (13) of the axial sections (5, 6) and is in the form of a straight line.

4. Tread profile according to Claim 1 or 2, characterized in that the depth profile of the circumferential section (11, 12) is configured such that the base (14) of said circumferential sections (11, 12) runs proceeding from the bulge (17) at the level of the residual depth (15) as far as the sipe base (13) of the axial sections (5, 6) and is of convex form, wherein the convex curvature preferably points radially outward.

5. Tread profile according to one or more of the preceding claims, characterized in that the axial sections (5, 6) have, at their radially inner end, a cavity (16) which is circular or oval in the cross section of the sipe (2), and said axial sections end in said cavity.

6. Pneumatic vehicle tire, characterized in that it has a tread profile (1) according to one or more of the preceding claims.

7. Pneumatic vehicle tire according to Claim 6, characterized in that it is a pneumatic utility vehicle tire.