VEHICLE AIR TIRES

Description

[0001] The invention relates to a pneumatic vehicle tire with a tread with profile blocks or at least one profile rib, each with cuts extending in plan view at an angle of 0° to 50° to the axial direction, having a cut base and a cut center surface, with a width of 0.4 mm to 1.2 mm and a maximum depth which corresponds at least to the tread depth reduced by 2.0 mm, wherein each cut, at least in a partial area present in plan view, has, viewed in cross section, a radially outer cut section inclined to the radial direction, a radially inner cut section extending to the cut base and inclined in the same direction as the radially outer cut section with respect to the radial direction, and a central cut section extending between these two cut sections,wherein the incision center surface has a radially outer kink at the connection of the radially outer incision section to the middle incision section and a radially inner kink at the connection of the middle incision section to the radially inner incision section, wherein the radially outer incision section and the radially inner incision section each have a length of 2.0 mm to 3.0 mm, determined in the radial direction, related to the incision center surface, wherein the radially inner kink of the incision center surface, a) on a first reference line running in the radial direction, which runs through the incision center surface at the radially outer end of the radially outer incision section, b) on a second reference line running in the radial direction, which runs through the radially outer kink point of the incision center surface, or c) lies between the first reference line and the second reference line.

[0002] Such a pneumatic vehicle tire is known, for example, from US 2005 / 0150581 A1. According to one exemplary embodiment, the pneumatic vehicle tire has a tread with profile blocks which are provided with sipes which, when viewed in plan, run in a zigzag shape and have a width of in particular 0.5 mm to 1.0 mm. The sipes, viewed in cross-section, also run in a zigzag shape and are composed of a radially outer sipe section, a radially inner sipe section, and a central sipe section, wherein the sipe sections are each inclined to the radial direction. The radially inner kink lies on a reference line running in the radial direction, which runs at the radially outer end of the radially outer sipe section through the central sipe surface.In the case of sipes corresponding to such incisions, which form the incisions during the vulcanization of the tire, the risk of these sipes bending when the tire is removed from the vulcanization mold should be reduced.

[0003] From US 2015 / 0266346 A1, another pneumatic vehicle tire is known with a tread with profile blocks which have cuts which are composed of several cut sections in the radial direction in such a way that the cuts run in a zigzag shape in the radial direction.

[0004] EP 2 138 330 A1 discloses a pneumatic vehicle tire with a tread having profile blocks with cuts, which, viewed in cross-section, each have at least three cut sections adjoining one another in a zigzag shape. The radially outer and radially inner cut sections have a greater length in the radial direction than the central cut section. The central cut section has a greater width than the radially inner and radially outer cut sections. The profile blocks are intended to exhibit low rigidity and high mobility during rolling. When subjected to high dynamic forces, for example during braking, the profile blocks are intended to behave similarly to profile blocks without cuts.

[0005] Furthermore, DE 10 2007 059 291 A1 discloses a pneumatic vehicle tire whose tread, according to one exemplary embodiment, has profile blocks which are provided with incisions which, when viewed in plan, run in a wave-like manner, in particular reaching the profile depth, and have a width of 0.4 mm to 0.6 mm, which, viewed in cross-section, have a radially outer incision section, a central incision section and a radially inner incision section. The radially outer incision section runs at an acute angle to the radial direction while maintaining its wave shape. The central incision section adjoins the radially outer incision section via a kink region, wherein in the central incision section the amplitude of the wave shape continuously decreases to zero in the direction of the radially inner end of the central incision section.The radially outer sipe section and the central sipe section each run at an angle of 20° to 50°, particularly approximately 35°, to the radial direction. The radially inner sipe section runs in the radial direction and is unstructured. The tire is designed to exhibit balanced driving characteristics on dry, snow-covered, and wet roads.

[0006] WO 94 / 21478 A1 discloses a pneumatic vehicle tire which, according to one embodiment, has a tread with profile blocks with sipes extending in the axial direction in plan view, each sipe having a width of 0.4 mm to 0.6 mm. Each sipe, viewed in cross-section, runs in a zigzag shape and is composed of a radially outer sipe section, a central sipe section, and a radially inner sipe section.

[0007] The cuts formed in the positive tread pattern of tires of the type mentioned above are particularly beneficial for snow performance. Given the changing stiffness of the positive tread pattern over time, these cuts could be improved, particularly to prevent uneven wear caused by an uneven decrease in the positive tread pattern's stiffness.

[0008] The invention is therefore based on the object of ensuring good snow performance and uniform or substantially uniform stiffness of the profile positives over the tread wear in a pneumatic vehicle tire of the type mentioned at the outset.

[0009] The stated object is achieved according to the invention in that the radially outer incision section runs at an angle of 15° to 30° to the radial direction, the radially inner incision section runs at an angle of 15° to 30° to the radial direction and the middle incision section runs at an angle of 0° to the radial direction, wherein the incision is composed at least in the partial area of ​​the radially outer incision section, the radially inner incision section and the middle incision section.

[0010] Alternatively, the stated object is achieved according to the invention in that the radially outer cut section runs at an angle of 15° to 30° to the radial direction, the radially inner cut section runs at an angle of 15° to 30° to the radial direction and the middle cut section runs at an angle of 0° to the radial direction, wherein the cut is composed, at least in the partial area, of the radially outer cut section, the radially inner cut section, the middle cut section and a further cut section running at an angle of 0° to 2° to the radial direction and starting from the tread periphery and having a length determined in the radial direction of up to 1.0 mm, in particular of up to 0.5 mm.

[0011] The radially outer sipe section, with its special angle relative to the radial direction, enables a very favorable grip behavior in the area of ​​the sipe edges for new or slightly worn tires. Similarly, the radially inner sipe section provides a further "performance boost" for snow grip when the tread is significantly worn. This ensures good snow performance across the entire tread wear. The special position of the radially inner kink in the sipe center area ensures uniform stiffness of the tread elements throughout the tread wear.

[0012] The design of the central sipe section ensures particularly uniform stiffness of the profile positives over the tread wear.

[0013] The additional cut section leaves the previously described beneficial effects of the radially outer cut section on snow grip properties unaffected. The additional cut section is advantageous primarily for manufacturing reasons during vulcanization mold production.

[0014] According to a further preferred embodiment, the incision in the partial area is made in the radial direction to the maximum depth, whereby the object is achieved in a particularly advantageous manner.

[0015] Preferably, the maximum depth of the cut is no more than 100% of the tread depth.

[0016] In particular, the maximum depth of the cut is at most the profile depth reduced by 0.5 mm, preferably at most 1.5 mm.

[0017] Preferably, the angle at which the radially outer cut section extends to the radial direction is 18° to 27°, in particular 20° to 25°. Such an angle is advantageous for snow grip properties in new or slightly worn tires.

[0018] In particular, it is advantageous for the aforementioned performance boost if the angle at which the radially inner cut section runs to the radial direction is 18° to 27°, in particular 20° to 25°.

[0019] A further preferred embodiment is characterized in that the angle at which the radially outer cut section extends to the radial direction deviates from the angle at which the radially inner cut section extends to the radial direction by a maximum of 3°, or that these angles coincide. This measure also contributes to uniform stiffness of the profile positives over tread wear.

[0020] A further preferred embodiment, which contributes to the uniform stiffness of the profile positives over the tread wear, is characterized in that the length of the radially outer cut section deviates from the length of the radially inner cut section by at most 0.3 mm or that these lengths are the same.

[0021] Preferably, the length of the radially outer incision section and the length of the radially inner incision section is up to 2.5 mm.

[0022] Further features, advantages and details of the invention will now be described in more detail with reference to the drawing, which schematically shows exemplary embodiments. Fig. 1 a section through a profile block of a tread of a pneumatic vehicle tire with an embodiment variant of the invention and Fig. 2a section through a profile block of a tread of a pneumatic vehicle tire with an embodiment not falling within the scope of protection of the claims.

[0023] Pneumatic vehicle tires designed according to the invention are tires for motor vehicles, in particular for multi-track motor vehicles, and preferably tires of radial design for passenger cars, vans or light trucks (light trucks with a GVW ≤ 7.5 t), wherein the tires are intended in particular for year-round use or for driving under winter driving conditions.

[0024] Fig. 1 and Fig. 2 each show a cross-section through a profile block 1 ( Fig. 1 ), 2 ( Fig. 2 ), which belongs to a tread of a pneumatic vehicle tire. The tread has a plurality of profile blocks 1 and / or 2. The circumferential direction of the tire is indicated by a double arrow U. The profile block 1, 2 is circumferentially separated by Fig. 1 and Fig. 2only indicated transverse grooves 3 and laterally by further grooves not shown, for example circumferential grooves.

[0025] In the embodiments shown, the transverse grooves 3 are designed in the radial direction to the respectively intended tread depth TP, which in the mentioned, preferred tire type is usually 6.5 mm to 12.0 mm, in particular 7.0 mm to 9.5 mm.

[0026] The profile block 1, 2 has an outer surface 4 on the tread periphery and is provided - in relation to its circumferential extent - in its central region with a cut 5 (profile block 1), 6 (profile block 2) extending from the outer surface 4 into the radial interior of the profile block 1, 2 with two cut edges 9 located on the outer surface 4 of the block. Fig. 1 and Fig. 2 The cross-section shown runs, viewed in plan view (not shown), perpendicular to the incision edges 9.

[0027] The cut 5, 6 can traverse the profile block 1 or 2 or end on one or both sides within the profile block 1, 2 and runs, in each case viewed in plan view, at an angle of 0° to 50°, in particular of up to 35°, to the axial direction, and can be straight, curved, wavy, or wavy and additionally curved overall. In the case of cuts that are generally straight in plan view, the angle refers to the cut center line, and in the case of cuts that are curved or curved overall in plan view, the angle refers to a straight line connecting the ends of the cut center line. In the case of wavy cuts, the cut center line coincides with the wave center line corresponding to the direction of propagation of the wave in plan view.

[0028] The incision 5, 6 is delimited by two opposing incision walls 7 extending from the incision edges 9 and by an incision base 8, has a constant width b E of 0.4 mm to 1.2 mm, in particular of up to 0.8 mm, determined between and perpendicular to the incision walls 7, a maximum depth t E (depth at the deepest point) measured in the radial direction and an incision center area m F that is spaced correspondingly from the incision walls 7, 7'. The maximum depth t E is at least the profile depth TP reduced by 2.0 mm and at most 100% of the profile depth TP , wherein the maximum depth t E preferably corresponds to at most the profile depth TP reduced by 0.5 mm, particularly preferably to at most 1.5 mm. In the exemplary embodiment shown, the incision 5, 6 is designed to the maximum depth t E over its entire extent.

[0029] The incision 5, 6, viewed in a cross-section running perpendicular to the incision edges 9 in plan view, has a straight, radially outer incision section 10a, a straight, central incision section 10b adjoining said incision, and a straight, radially inner incision section 10c. In the exemplary embodiment shown, the incision 5, 6 is composed of the incision sections 10a, 10b, 10c. Alternatively, in addition to the incision sections 10a, 10b, 10c, the incision 5, 6 can have, in addition to the incision sections 10a, 10b, 10c, a further incision section running in the radial direction or at an angle of 0° to 2° thereto, starting from the block outer surface 4 and adjoining the radially outer incision section 10a, which - based on the incision central area m F - has a length determined in the radial direction of up to 1.0 mm, in particular of up to 0.5 mm.

[0030] The following further explanations refer to the cross-section through the incision 5, 6, which runs perpendicular to the incision edges 9 in plan view.

[0031] The radially outer incision section 10a runs at an angle α of 15° to 30°, in particular of 18° to 27°, preferably of 20° to 25°, to the radial direction and has - based on the incision center area m F - a length ca determined in the radial direction of 2.0 mm to 3.0 mm, in particular of up to 2.5 mm. The radially inner incision section 10c runs at an angle γ of 15° to 30°, in particular of 18° to 27°, preferably of 20° to 25°, to the radial direction and has - based on the incision center area m F - a length cc determined in the radial direction of 2.0 mm to 3.0 mm, in particular of up to 2.5 mm. Preferably, the length ca deviates from the length cc by a maximum of 0.3 mm, with it being particularly preferred if the lengths ca and cc are identical. Preferably, the angle α deviates from the angle γ by a maximum of 3°. Particularly preferably, the angle α is identical to the angle γ.

[0032] The incision center surface m F has a radially outer kink point K a at the mutual connection of the incision sections 10a, 10b and a radially inner kink point K b at the mutual connection of the incision sections 10b, 10c, wherein the kink points K a , K b appear as kink points in the cross section shown. In Fig. 1 and Fig. 2 a reference line L 1 running in the radial direction through the radially outer end of the incision center surface m F and a reference line L 2 running in the radial direction through the radially outer kink point K a are shown.

[0033] The design of the incision 5, 6 is such that the kink point K b is located on the reference line L 1 , on the reference line L 2 (incision 5) or between the reference line L 1 and the reference line L 2 (incision 6).

[0034] Preferably, the design of the incision 5, 6 is further such that the central incision section 10b - relative to the incision central area m F - extends to the radial direction at an angle β of 0° to 30°, in particular of up to 20°, preferably of up to 18°, particularly preferably of up to 15°, most particularly preferably of up to 10°. In the embodiment in Fig. 1 the angle β is 0°.

[0035] The invention is not limited to the described embodiment.

[0036] In particular, the incisions can also be formed in profile ribs that run circumferentially. The profile rib or the profile blocks can be provided with several of the incisions. Furthermore, the incisions can run in a shoulder-side profile rib or in shoulder-side profile blocks. The incisions each have the described three incision sections in at least a portion of the associated incision, with this portion preferably extending at least over the majority of the incision in plan view. List of reference symbols

[0037] 1Tread block 2Tread block 3Transverse groove 4Block outer surface 5Cut 6Cut 7Cut wall 8Cut base 9Cut edge 10aradial outer cut section 10bmiddle cut section 10cradial inner cut section b E Width C a , C c Length K a radial outer kink K b radial inner kink L 1 , L 2 Reference line m F Cut center area t E Maximum depth TP Profile depth U Double arrow (circumferential direction) a, β, γ Angle

Claims

1. Pneumatic vehicle tyre having a tread with profile blocks (1, 2) or at least one profile rib, in each case having sipes (5) which, in plan view, extend at an angle of 0° to 50° to the axial direction, have a sipe base (8) and a sipe midsurface (mF), have a width (bE) of 0.4 mm to 1.2 mm and have a maximum depth (tE) which corresponds at least to the profile depth (TP) reduced by 2.0 mm, wherein, at least in a sub-region present in plan view, each sipe (5), when viewed in the cross section, has a radially outer sipe portion (10a) inclined in relation to the radial direction, a radially inner sipe portion (10c) extending as far as the sipe base (8) and inclined in the same direction as the radially outer sipe portion (10a) in relation to the radial direction, and a middle sipe portion (10b) extending between these two sipe portions (10a, 10c), wherein the sipe midsurface (mF) has a radially outer bend (Ka) at the connection of the radially outer sipe portion (10a) to the middle sipe portion (10b) and a radially inner bend (Kb) at the connection of the middle sipe portion (10b) to the radially inner sipe portion (10c), wherein the radially outer sipe portion (10a) and the radially inner sipe portion (10c) each have a length (ca, cc) of 2.0 mm to 3.0 mm based on the sipe midsurface (mF) and determined in a radial direction, wherein the radially inner bend (Kb) of the sipe midsurface (mF) is situated a) on a first reference line (L1) which extends in the radial direction and extends through the sipe midsurface (mF) at the radially outer end of the radially outer sipe portion (10a), b) on a second reference line (L2) which extends in the radial direction and extends through the radially outer bend (Ka) of the sipe midsurface (mF), or c) between the first reference line (L1) and the second reference line (L2), characterized in that the radially outer sipe portion (10a) extends at an angle (α) of 15° to 30° to the radial direction, the radially inner sipe portion (10c) extends at an angle (γ) of 15° to 30° to the radial direction and the middle sipe portion (10b) extends at an angle (β) of 0° to the radial direction, wherein, at least in the sub-region, the sipe (5) is made up of the radially outer sipe portion (10a), the radially inner sipe portion (10c) and the middle sipe portion (10b).

2. Pneumatic vehicle tyre having a tread with profile blocks (1, 2) or at least one profile rib, in each case having sipes (5) which, in plan view, extend at an angle of 0° to 50° to the axial direction, have a sipe base (8) and a sipe midsurface (mF), have a width (bE) of 0.4 mm to 1.2 mm and have a maximum depth (tE) which corresponds at least to the profile depth (TP) reduced by 2.0 mm, wherein, at least in a sub-region present in plan view, each sipe (5), when viewed in the cross section, has a radially outer sipe portion (10a) inclined in relation to the radial direction, a radially inner sipe portion (10c) extending as far as the sipe base (8) and inclined in the same direction as the radially outer sipe portion (10a) in relation to the radial direction, and a middle sipe portion (10b) extending between these two sipe portions (10a, 10c), wherein the sipe midsurface (mF) has a radially outer bend (Ka) at the connection of the radially outer sipe portion (10a) to the middle sipe portion (10b) and a radially inner bend (Kb) at the connection of the middle sipe portion (10b) to the radially inner sipe portion (10c), wherein the radially outer sipe portion (10a) and the radially inner sipe portion (10c) each have a length (ca, cc) of 2.0 mm to 3.0 mm based on the sipe midsurface (mF) and determined in a radial direction, wherein the radially inner bend (Kb) of the sipe midsurface (mF) is situated a) on a first reference line (L1) which extends in the radial direction and extends through the sipe midsurface (mF) at the radially outer end of the radially outer sipe portion (10a), b) on a second reference line (L2) which extends in the radial direction and extends through the radially outer bend (Ka) of the sipe midsurface (mF), or c) between the first reference line (L1) and the second reference line (L2), characterized in that the radially outer sipe portion (10a) extends at an angle (α) of 15° to 30° to the radial direction, the radially inner sipe portion (10c) extends at an angle (γ) of 15° to 30° to the radial direction and the middle sipe portion (10b) extends at an angle (β) of 0° to the radial direction, wherein, at least in the sub-region, the sipe (5) is made up of the radially outer sipe portion (10a), the radially inner sipe portion (10c), the middle sipe portion (10b) and a further sipe portion which extends at an angle of 0° to 2° to the radial direction, proceeds from the tread periphery and has a length of up to 1.0 mm, in particular of up to 0.5 mm, determined in a radial direction.

3. Pneumatic vehicle tyre according to Claim 1 or 2, characterized in that, in the sub-region, the sipe (10) is formed to the maximum depth (tE) in the radial direction.

4. Pneumatic vehicle tyre according to one of Claims 1 to 3, characterized in that the maximum depth (tE) of the sipe (5) is at most 100% of the profile depth (TP).

5. Pneumatic vehicle tyre according to one of Claims 1 to 3, characterized in that the maximum depth (tE) of the sipe (5) is at most the profile depth (TP) reduced by 0.5 mm, preferably at most said profile depth reduced by 1.5 mm.

6. Pneumatic vehicle tyre according to one of Claims 1 to 5, characterized in that the angle (α) at which the radially outer sipe portion (10a) extends to the radial direction is 18° to 27°, in particular 20° to 25°.

7. Pneumatic vehicle tyre according to one of Claims 1 to 6, characterized in that the angle (γ) at which the radially inner sipe portion (10c) extends to the radial direction is 18° to 27°, in particular 20° to 25°.

8. Pneumatic vehicle tyre according to one of Claims 1 to 7, characterized in that the angle (α) at which the radially outer sipe portion (10a) extends to the radial direction differs from the angle (γ) at which the radially inner sipe portion (10c) extends to the radial direction by at most 3°, or in that these angles (α, γ) correspond.

9. Pneumatic vehicle tyre according to one of Claims 1 to 8, characterized in that the length (ca) of the radially outer sipe portion (10a) differs from the length (cc) of the radially inner sipe portion (10c) by at most 0.3 mm, or in that these lengths (ca, cc) correspond.

10. Pneumatic vehicle tyre according to one of Claims 1 to 9, characterized in that the length (ca) of the radially outer sipe portion (10a) and the length (cc) of the radially inner sipe portion (10c) are up to 2.5 mm.