VEHICLE AIR TIRES

Description

[0001] The invention relates to a vehicle pneumatic tire with a tread featuring profile blocks or at least a circumferentially circumferential profile rib, in which, in plan view, incisions are formed extending at an angle of 0° to 50° to the axial direction, having a width of 0.4 mm to 2.0 mm, a maximum depth of 60% to 100% of the tread depth, incision walls and a incision base, wherein each incision, viewed in cross-section, has a radially outer incision section extending at an angle of 15° to 55° to the radial direction and a radially inner incision section adjoining this, extending at an angle of 0° to 5° to the radial direction and reaching to the incision base, wherein the incision sections form an obtuse angle with each other, so that the incision has a kink at the mutual connection of the incision sections.one cut wall runs along the inside of the bend and the other cut wall along the outside of the bend, and the cut walls in the radially outer cut section have radially outer wall sections and in the radially inner cut section have radially inner wall sections.

[0002] Such a vehicle pneumatic tire is known, for example, from DE 41 07 547 A1. According to one embodiment, the tire has a tread with profile blocks which are provided with spatially curved incisions extending axially in plan view. In cross-section, these incisions consist of a radially outer incision section extending at an angle of 20° to 60° to the radial direction and a radially inner incision section extending at an angle of 5° to 20° to the radial direction, the radially inner incision section being inclined in the opposite direction to the radially outer incision section with respect to the radial direction. The incisions create gripping edges on the outer surface of the profile positives, which are intended to enable good adaptation to fine structures in the ground.

[0003] CN 101085591 A, JP H0994829 A, JP H11151914A and US 8146631 B2 each disclose a pneumatic vehicle tire having a tread with profile blocks comprising cuts, wherein the cuts have cut walls oriented at an angle to the radial direction.

[0004] The invention is based on the objective of further improving the wet and snow performance of a vehicle pneumatic tire of the type mentioned above.

[0005] The stated object is achieved according to the invention in that at least one recess which is elongated in the radial direction is formed locally on the incision wall of the incision running over the inside of the bend, which recess runs over both wall sections and reaches to the base of the incision.

[0006] The cutouts in the tread pattern capture more snow or water when driving on wet and / or snowy roads compared to treads without cutouts. Since the cutouts are only located locally on the inner sidewall of the tread, the stiffness of the tread blocks remains advantageously unaffected. In new or nearly new tires, the tread blocks are particularly flexible, allowing them to open upon contact with the road surface and thus capture larger quantities of water and / or snow. As the tread wears down, the stiffness of the tread blocks increases, resulting in the tread blocks opening less sharply upon contact with the road surface.At the same time, as the tread wear progresses, the recesses approach the positive outer surfaces of the profile and thus provide additional empty volume directly from the (worn) tread periphery, so that good water and snow absorption properties are maintained and in this respect the decreasing opening ability of the cuts is compensated.

[0007] The cuts thus contribute to good wet and snow performance via tread abrasion.

[0008] According to a preferred embodiment, the recess extends to the radially outer end of the radially outer wall section of the incision wall extending along the inside of the bend. The recess therefore exhibits a beneficial effect even on new tires, with the beneficial effects for wet and snow performance advantageously becoming more pronounced even after minimal tread wear.

[0009] A very advantageous compromise between high profile stiffness and wet and snow performance is achieved when the recess, or each recess, on the radially inner wall section of the cut wall extending over the inner side of the bend has two, in particular, straight, radially inner boundary edges, between which the recess, or each recess, has a width determined parallel to the tread periphery at its narrowest point, wherein - in the case of a single recess on the respective cut - the width occupies 15% to 40%, preferably 20% to 30%, of the length of the cut, and wherein - in the case of several recesses on the respective cut - the widths of the recesses together occupy 15% to 40%, preferably 20% to 30%, of the length of the cut.

[0010] According to another preferred embodiment, the recess has a bottom surface that is level with the base of the cut. The recess is therefore correspondingly deep, which is particularly advantageous for wet performance and ensures that the beneficial effect of the recess is maintained throughout the entire tread wear.

[0011] In the latter design, it is advantageous if the floor surface is trapezoidal, particularly isosceles trapezoidal, with a base located at the base of the cut, a floor edge opposite it forming the shorter base side of the trapezoid, and two additional floor edges. In such a cutout, snow compaction and snow grip are improved when driving on snow.

[0012] Preferably, the latter embodiment is further characterized in that the recess is delimited by a flat rear wall extending from the radially outer end of the radially outer wall section to the bottom surface.

[0013] For snow compaction and snow retention in the recess, it is further advantageous if the recess on the rear wall has a width, measured parallel to the tread periphery at the narrowest point, of 75% to 95% of the width measured between the radially inner boundary edges of the recess at the narrowest point parallel to the tread periphery.

[0014] According to a further preferred embodiment, the recess is delimited by two flat side walls extending from the radially outer wall section of the incision wall extending over the inside of the bend and extending to the bottom surface.

[0015] In a further preferred embodiment, the radially outer incision section adjoins the radially inner incision section at a depth determined in the radial direction of 30% to 50%, in particular 35% to 45%, of the maximum depth of the incision.

[0016] According to a further preferred embodiment, the angle at which the radially outer incision section runs to the radial direction is 20° to 45°, preferably 25° to 35°.

[0017] Furthermore, it is preferred if the radially inner incision section, viewed in cross-section, runs at an angle of 0° to 3° to the radial direction.

[0018] Another preferred embodiment is characterized in that the incisions traverse the profile positives. Such incisions—compared to incisions that terminate at least on one side within the profile positives—exhibit a more pronounced opening behavior when passing through the ground contact surface, so that the advantageous effects of the recess are particularly evident.

[0019] The effect of the recess is particularly uniform if it has a plane of symmetry running in the radial direction and in plan view perpendicular to the direction of extension of the incision.

[0020] According to a further preferred embodiment, cuts are provided, each having at least two, in particular up to three, recesses. Multiple recesses are advantageous because they provide a larger empty volume inside the cut without excessively influencing the rigidity of the positive profile.

[0021] Further features, advantages and details of the invention will now be described in more detail with reference to the drawing, which schematically shows an embodiment of the invention. Fig. 1 a simplified top view of a profile block of a tread of a vehicle pneumatic tire with an embodiment of the invention, Fig. 2 a section along line II-II of the Fig. 1 , Fig. 3 an oblique view of the profile block in wireframe representation and Fig. 4 a visualization of an incision (subtraction body of the incision).

[0022] Vehicle pneumatic tires designed according to the invention are tires for motor vehicles, in particular for multi-track motor vehicles, and preferably radial tires for passenger cars, vans or light trucks (light trucks with a gross vehicle weight ≤ 7.5 t), wherein the tires are particularly intended for all-season use.

[0023] Fig. 1 Figure 1 shows a top view of a tread block 1 belonging to the tread of a vehicle tire. The tread has a plurality of tread blocks 1. The circumferential direction of the tire is indicated by a double arrow U. The tread block 1 is divided laterally by Fig. 1 merely indicated circumferential grooves 2 and by transverse grooves 3 running between the circumferential grooves 2, also merely indicated, in the axial direction.

[0024] The circumferential grooves 2 and preferably also the transverse grooves 3 are radially tapered to the profile depth TP provided for the respective pneumatic vehicle tyre (indicated in Fig. 2 ), which is usually 6.5 mm to 12.0 mm, in particular 7.0 mm to 9.5 mm.

[0025] The profile block 1 has an outer surface 4 at the periphery of the tread and, with respect to its circumferential extent, is provided in its central region with a notch 5 extending from the outer surface 4 into the radial interior of the profile block 1. The notch 5 passes through the profile block 1, runs straight in plan view and in the axial direction in the illustrated embodiment, and has two straight edges 6 on the outer surface 4.

[0026] According to Fig. 2 The cut 5 is bounded by two cut walls 7, 7' extending from the cut edges 6, opposite each other and running parallel to each other, and a cut base 8, and has a constant width b E of 0.4 mm to 2.0 mm, in particular up to 1.2 mm, preferably up to 0.8 mm, determined between and perpendicular to the cut walls 7, 7', a preferably constant maximum depth t E (depth at the deepest point) of 60% to 100%, in particular 70% to 95%, measured in the radial direction, a cut center surface MF spaced at the same distance from the cut walls 7, 7', and a length IE measured at the level of the block outer surface 4 along the cut center surface MF ( Fig. 1 ) on.

[0027] The cut 5, viewed in cross-section perpendicular to the cut edges 6 (cf. position of section line II-II in Fig. 1 The cut 5 comprises a straight, radially inner cut section 5b and a straight, radially outer cut section 5a adjoining it, wherein the cut sections 5a and 5b form an obtuse angle β with respect to the cut center surface MF. In the illustrated embodiment, the cut 5 is composed of the cut sections 5a and 5b. Alternatively, in addition to the cut sections 5a and 5b, the cut 5 can have a further cut section extending radially or at an angle of up to 2° to it, extending from the outer block surface 4 and adjoining the radially outer cut section 5a, which extends radially to a depth of up to 1.5 mm with respect to the cut center surface MF.

[0028] The cut mid-surface MF has a kink line K at the mutual connection of the cut sections 5a, 5b (appears in the cross-section shown as a kink point), which runs at a constant depth t 1 determined in the radial direction of 30% to 50%, in particular of 35% to 45%, of the maximum depth t E of the cut 5.

[0029] The previously mentioned cut wall 7 runs along the inside of the bend and is therefore, viewed in cross-section, intersected by an auxiliary line h running straight between the ends of the cut mid-surface MF. The cut wall 7' runs along the outside of the bend, so that, viewed in cross-section, it is not intersected by the auxiliary line h.

[0030] The radially outer cut section 5a runs, viewed in cross-section perpendicular to the cut edges 6, to the radial direction at an angle α of 15° to 55°, in particular of 20° to 45°, preferably of 25° to 35°, and is bounded by a radially outer wall section 7a of the cut wall 7 extending over the inside of the bend and a radially outer wall section 7'a of the cut wall 7' extending over the outside of the bend.

[0031] The radially inner cut section 5b runs, viewed in cross-section perpendicular to the cut edges 6, in a radial direction, alternatively to the radial direction at an angle of up to 5°, in particular up to 3°, and is bounded by a radially inner wall section 7b of the cut wall 7 extending over the inside of the bend and a radially inner wall section 7'b of the cut wall 7' extending over the outside of the bend.

[0032] How Fig. 3 As shown, a radially elongated recess 9 is formed in the profile block 1, which interrupts the incision wall 7 running over the inside of the bend section in sections over its entire radial extent, and is therefore open to the radially outer incision section 5a and to the radially inner incision section 5b, to the circumferential grooves 2 ( Fig. 1 ) lying ends of the cut 5 is spaced apart and is located radially within the radially outer wall section 7a of the cut wall 7 running over the inside of the bend (cf. Fig. 4 The recess 9 extends radially from the radially outer wall section 7a into the interior of the profile block 1 and ends at the level of the cut base 8. According to Fig. 1 The recess 9 has a plane of symmetry E 1 extending radially and perpendicularly in plan view to the incision edges 6, which has an intersection point S with the incision mid-surface MF at the level of the block outer surface 4, which has a distance as to the circumferential grooves 2 measured along the incision mid-surface MF of 40% to 60% of the length IE of the incision 5.

[0033] How Fig. 3 Furthermore, the recess 9 has boundary edges formed on the incision wall 7 extending over the inside of the fold, to which two straight, radially outer boundary edges 10a formed on the radially outer wall section 7a are connected (cf. Fig. 4 ) and two straight, parallel to each other and, when viewed perpendicularly from the wall section 7b, radially inner boundary edges 10b (cf. Fig. 4 ) belong. The radially outer boundary edges 10a originate from the cut edge 6 associated with the cut wall 7, and extend from this edge into the interior of the cut 5, increasing their clear distance from each other (cf. Fig. 1 ) and end at the radially inner wall section 7b ( Fig. 4 ). The radially inner boundary edges 10b adjoin the radially outer boundary edges 10a and end at the base of the cut 8 (cf. Fig. 4 ).

[0034] The recess 9 is defined in a radial direction by an isosceles trapezoidal base surface 9a, a rectangular rear wall 9b opposite the incision wall 7' extending over the kick outer side (cf. Fig. 4 ) and two flat side walls 9c ( Fig. 4 ) limited.

[0035] The isosceles trapezoidal base surface 9a runs at the level of the cut bottom 8, therefore at the mentioned depth t E ( Fig. 2 ), has a base 9a` lying at the base of the incision 8, corresponding to the longer base of the trapezoid (in Fig. 3 (indicated by dots), two base edges 9a" each forming a leg of the trapezoid and a base edge 9a‴ running parallel to the base 9a', forming the shorter base of the trapezoid.

[0036] How Fig. 3 und Fig. 4 As shown in each case, the rectangular back wall 9b extends in a radial direction, originates from the incision edge 6 associated with the incision wall 7 running over the inside of the fold, and ends in a radial direction at the bottom edge 9a‴ forming the shorter base of the trapezoid. According to Fig. 4 The side walls 9c are each bounded by one of the radially outer boundary edges 10a, the radially inner boundary edge 10b adjoining these and the bottom edge 9a" adjoining these, each forming a trapezoidal leg.

[0037] According to Fig. 3 The recess 9 between its radially inner boundary edges 10b has a width b A determined parallel to the tread periphery, which is 15% to 40%, preferably 20% to 30%, of the length IE ( Fig. 1 ) of the cut 5. In the exemplary embodiment, the width b A is constant, since the limiting edges 10b, as already mentioned, run perpendicular to the corresponding cut edge 6 when viewed perpendicularly from the wall section 7b. The width of the recess 9 determined between the radially outer limiting edges 10a parallel to the periphery of the tread, as well as the width of the recess 9 determined between the bottom edges 9a" parallel to the periphery of the tread, each takes on a dimension starting from the radially inner wall section 7b ( Fig. 4 ) over the radially outer boundary edges 10a or over the bottom edges 9a" continuously to a width b A * ( Fig. 3 : Boundary edges 10a, Fig. 4: bottom edges 9a"). Each width b A * is 75% to 95% of the width b A determined at the narrowest point, in the exemplary embodiment 75% to 95% of the constant width b A .

[0038] The invention is not limited to the described embodiment.

[0039] In particular, the cuts can each have more than one recess, preferably up to three recesses. In plan view, the cuts can also be curved and / or wavy or the like, wherein the length of the cuts and the angle at which such cuts extend to the axial direction each refer to a straight line which, in plan view, connects the ends of the cut center surface located at the periphery of the tread. The tread can also have circumferential profile ribs in which the cuts are formed. The recess(s) can also end radially within the radially outer end of the radially outer cut section. List of reference symbols

[0040] 1Tread block 2Circumferential groove 3Transverse groove 4Block outer surface 5Cut 5aradial outer cut section 5bradial inner cut section 6Cut edge 7, 7'Cut wall 7a, 7'aradial outer wall section 7b, 7'bradial inner wall section 8Cut base 9Recess 9aBottom surface 9a'Base 9a"Bottom edge 9a‴Bottom edge 9bRear wall 9cSide wall 10aradial outer boundary edge 10bradial inner boundary edge a S Distance b E , b A , b A *Width E 1 Symmetry plane hAuxiliary line KKink line IE Length MF Cut center surface SSecession point t E Maximum depth t 1 Depth TP Profile depth U Double arrow (circumferential direction) α, βAngle

Claims

1. Pneumatic vehicle tyre having a tread having profile blocks (1) or at least one profile rib that is encircling in the circumferential direction, in which blocks or rib there are formed sipes (5) having sipe walls (7, 7') and a sipe bottom (8), said sipes extending, as seen in plan view, at an angle of 0° to 50° in relation to the axial direction, and having a width (bE) of 0.4 mm to 2.0 mm and a maximum depth (tE) of 60% to 100% of the profile depth (TP), wherein each sipe (5), as viewed in cross section, has a radially outer sipe portion (5a) which extends at an angle (α) in relation to the radial direction and, adjoining the latter, a radially inner sipe portion (5b), which extends at an angle in relation to the radial direction and extends down to the sipe bottom (8), wherein the sipe portions (5a, 5b) conjointly enclose an obtuse angle (β) in such a way that the sipe (5) has a kink where the sipe portions (5a, 5b) join one another, the one sipe wall (7) extends over the inner side of the kink and the other sipe wall (7`) extends over the outer side of the kink, and the sipe walls (7, 7`) have radially outer wall sections (7a, 7'a) in the radially outer sipe portion (5a) and radially inner wall sections (7b, 7'b) in the radially inner sipe portion (5b), characterized in that the angle (α) at which the radially outer sipe portion (5a), viewed in cross section, runs in relation to the radial direction is 15° to 55°, in that the angle at which the radially inner sipe portion (5b), viewed in cross section, runs in relation to the radial direction is 0° to 5°, and in that at the sipe wall (7) of the sipe (5) extending over the inner side of the kink, at least one recess (9) extending in the radial direction is in each case formed locally, which extends over both wall sections (7a, 7b) and extends down to the sipe bottom (8).

2. Pneumatic vehicle tyre according to Claim 1, characterized in that the recess (9) extends up to the radially outer end of the radially outer wall section (7a) of the sipe wall (7) extending over the inner side of the kink.

3. Pneumatic vehicle tyre according to Claim 1 or 2, characterized in that the or each recess (9) on the radially inner wall section (7b) of the sipe wall (7) extending over the inner side of the kink has two particularly straight, radially inner boundary edges (10b), between which the or each recess (9) at the narrowest point has a width (bA) determined parallel to the running strip periphery, wherein - in the case of a single recess (9) at the respective sipe (5) - the width (bA) occupies 15% to 40%, preferably 20% to 30%, of the length (lE) of the sipe (6), and wherein - in the case of several recesses (9) at the respective sipe (5) - the widths (bA) of the recesses (9) conjointly occupy 15% to 40%, preferably 20% to 30%, of the length (lE) of the sipe (6).

4. Pneumatic vehicle tyre according to one of Claims 1 to 3, characterized in that the recess (9) has a bottom area (9a) formed at the same level as the sipe bottom (8).

5. Pneumatic vehicle tyre according to Claim 4, characterized in that the bottom area (9a) is trapezoidal, in particular isosceles trapezoidal, wherein it has a base (9a') lying at the sipe bottom (8), a bottom edge (9a‴) opposite thereto and forming the shorter bottom side of the trapezoid, and two further bottom edges (9'a).

6. Pneumatic vehicle tyre according to Claim 4 or 5, characterized in that the recess (9) is conjointly delimited by a flat rear wall (9b) extending from the radially outer end of the radially outer wall section (7a) to the bottom area (9a).

7. Pneumatic vehicle tyre according to Claims 3 and 6, characterized in that the recess (9) on the rear wall (9b), at the narrowest point, has a width (bA*) determined parallel to the running strip periphery of 75% to 95% of the width (bA) determined between the radially inner boundary edges (10b) of the recess (9), at the narrowest point parallel to the running strip periphery.

8. Pneumatic vehicle tyre according to one of Claims 4 to 7, characterized in that the recess (9) is conjointly delimited by two flat side walls (9c) which proceed from the radially outer wall section (7a) of the sipe wall (7) and extend by way of the inner side of the kink and extend to the bottom area (9a).

9. Pneumatic vehicle tyre according to one of Claims 1 to 8, characterized in that that the radially outer sipe portion (5a) adjoins the radially inner sipe portion (5b) at a depth (t1) determined in the radial direction of 30% to 50%, in particular 35% to 45%, of the maximum depth (tE) of the sipe (5).

10. Pneumatic vehicle tyre according to one of Claims 1 to 9, characterized in that the angle (α) at which the radially outer sipe portion (5a) runs in relation to the radial direction is 20° to 45°, preferably 25° to 35°.

11. Pneumatic vehicle tyre according to one of Claims 1 to 10, characterized in that the radially inner sipe portion (5b), as viewed in cross section, runs at an angle of 0° to 3° in relation to the radial direction.

12. Pneumatic vehicle tyre according to one of Claims 1 to 11, characterized in that the sipes (5) traverse the profile positives (1).

13. Pneumatic vehicle tyre according to one of Claims 1 to 12, characterized in that the recess (9) has a plane of symmetry (E1) running in the radial direction and in plan view perpendicularly to the direction of extent of the sipe (5).

14. Pneumatic vehicle tyre according to one of Claims 1 to 13, characterized in that sipes (5) which have in each case at least two, in particular in each case up to three, recesses (9) are provided.