VEHICLE TIRES

Description

[0001] The invention relates to a vehicle pneumatic tire with a tread having at least one circumferentially circumferential profile rib bounded on at least one side by a circumferential groove, with an outer surface located at the periphery of the tread, and with incisions, in particular, running parallel to each other and at an angle of up to 45° to the axial direction, which open into at least one circumferential groove and terminate within the profile rib or have a cut section terminating within the profile rib and opening into the circumferential groove, wherein the cuts terminating within the profile rib orThe cut sections each have a cut wall extending radially in the direction between the cut base and the outer surface of the profile rib, and opposite this, a further cut wall combined with a chamfer, also extending radially, wherein the chamfer runs at an acute angle to the outer surface of the profile rib and, viewed in cross-section of the respective cut or cut section, to the radial direction, wherein a plateau with a width of 0.30 mm to 0.80 mm is formed between the chamfer and the further cut wall, preferably at a constant depth and preferably parallel to the outer surface of the profile rib, wherein the angle of the chamfer relative to the radial direction decreases continuously from its end on the inside of the profile rib to its end on the circumferential groove side.

[0002] Such a pneumatic tire is known, for example, from DE 10 2018 208 670 A1. This pneumatic tire has a tread with a profile rib bounded on both sides by circumferential grooves, which is provided with transverse cuts. Viewed from above, these cuts are each composed of edge-side cut sections opening into the circumferential grooves and a central cut section. The edge-side cut sections each have a length, projected axially, of 20% to 40%, in particular 25% to 25%, of the width of the profile rib at the rib's outer surface.In each edge-side cut section, one cut wall extends to the outer surface of the profile rib, and the other cut wall is combined with a chamfer running towards the outer surface of the profile rib. Viewed in cross-section, this chamfer is inclined at an angle of 30° to 70°, particularly 40° to 50°, to the radial direction. The angle of the chamfer increases continuously from the respective circumferential groove, in particular by 1° to 3°, towards the central cut section, and therefore decreases continuously from the end of the chamfer on the inside of the profile rib to the end of the chamfer on the circumferential groove side. A plateau, curved in particular along a radius and with a width of 0.5 mm to 1.2 mm, is formed between the chamfer and the cut wall.In the edge sections of the cut, a raised section is formed at a distance from the nearest circumferential groove. This raised section has a top surface that is inverted U-shaped in the longitudinal section of the cut, and adjoining this surface are side surfaces that curve in the opposite direction to the U-shape of the top surface without any kinks. These raised sections are beneficial for stabilizing the edges of the profile ribs. Their top surface is designed to allow water absorbed by the cut to drain away largely without turbulence, thus improving drainage of the profile rib. The chamfers facilitate a low-turbulence flow of water into the cut and locally increase the cross-sectional area of ​​the cut at the periphery of the tread, further improving drainage.

[0003] From EP 3 208 113 A1, a vehicle pneumatic tire is known with a tread having profile blocks arranged within profile ribs. These blocks are separated from one another in plan view by axially extending transverse grooves and are each traversed by a number of cuts running parallel to the transverse grooves. The cuts preferably have a substantially uniform cross-section along their length. Each cut is bounded by two cut walls and a cut base. According to one embodiment, one cut wall extends radially to the outer surface of the tread, and the other cut wall is combined with a chamfer, with a plateau formed between the chamfer and the cut wall.The chamfer, viewed in cross-section, runs straight and at an angle of 30° to 70° to the radial direction, particularly 40° to 50°, the angle preferably being constant or alternatively varying along the cut path. The plateau forms a local indentation and has a width of 0.5 mm to 1.2 mm. The cuts can alternatively terminate within the profile ribs. The plateau, forming a local indentation, increases the water absorption capacity of the cuts, thus providing good drainage and, in particular, improving wet braking performance.

[0004] Furthermore, DE 10 2015 202 613 A1 discloses a pneumatic tire for vehicles with a tread that has at least one profile rib bounded by circumferential grooves, in which a plurality of transverse cuts are formed. The cuts are widened by a chamfer at least in a section of their extent and on the outer surface of the rib. These cut sections are arc-shaped in plan view, with the chamfers formed on the inner side of the cut wall. The chamfers run at a constant angle, in the range of 35° to 50°, to the radial direction and taper off on the inner side of the profile rib, decreasing in width and depth as they approach the outer surface of the profile rib. Cuts in the profile ribs designed in this way are intended to reduce noise emissions and improve wet braking performance.

[0005] From DE 10 2016 221 954 A1, a vehicle pneumatic tire with a profiled tread is known, which has at least one profile rib that is bounded axially, i.e., laterally, by a circumferential groove on each side. V-shaped incisions are present in the profile rib, the sections of which each open into the same circumferential groove and whose connecting kink lies within the profile rib. On one of the V-sections, one wall of the incision is chamfered at the transition to the outer surface of the profile rib. This chamfer runs at a constant angle to the radial direction over its length, but with varying depth, such that the chamfer has its deepest point and greatest width at the end on the inner side of the profile rib.A tire with such a tread pattern should have better aquaplaning resistance with high stiffness of the tread rib to achieve good dry braking and handling characteristics.

[0006] Furthermore, numerous patent publications are known in which pneumatic vehicle tires with profiled treads and profile ribs are disclosed, in which wide transverse grooves are formed that terminate within the profile rib and one groove flank of which is chamfered at the transition to the outer surface of the profile rib. For example, EP 3 135 505 B1 discloses such a pneumatic vehicle tire.

[0007] It is therefore known and common to form transverse grooves or incisions in profile ribs, which have chamfered edges to prevent these edges from rolling in during braking.

[0008] The invention is based on the objective of further improving the design of chamfers at cuts or cut sections in profile ribs of treads in a tire of the type mentioned above in order to optimize the braking performance of the tire, while maintaining or remaining unaffected by the noise development when the tire rolls at a good level.

[0009] The problem stated in the invention is solved by the fact that the angle which the chamfer encloses with the radial direction at its circumferential groove-side end is at least 10° smaller than the angle which the chamfer encloses with the radial direction at its profile rib-inside end, wherein the notch ending within the profile rib or the notch section ending within the profile rib extends with respect to the width of the profile rib determined on the outer surface in the axial direction at least to the middle of the profile rib and in particular over up to 80% of the width of the profile rib determined on the outer surface in the axial direction.

[0010] In this invention, the chamfers not only prevent the cut edges from rolling inwards, but are also designed such that they are most pronounced in the area of ​​the center of the tread rib due to their large angle relative to the radial direction. This is particularly advantageous for braking performance because the ground pressure on the tread rib is highest in the central area during braking and lowest at the edges. Furthermore, the plateaus between the cut walls and the chamfers widen the cuts, which is beneficial for water drainage. The noise generated when the tire rolls remains unaffected by these measures and is not negatively impacted.

[0011] The aforementioned minimum extent of the cut or cut section is advantageous in order to achieve a noticeable effect from the combination of plateau / chamfer.

[0012] In a preferred embodiment, the angle formed by the chamfer at its inner profile rib end with the radial direction is 20° to 60°, particularly 30° to 45°. In a particularly preferred embodiment, the angle formed by the chamfer at its circumferential groove end with the radial direction is 0° to 10°, particularly 0° to 5°. Chamfers designed and shaped in this way have a particularly effective impact on the tire's braking performance.

[0013] In another advantageous embodiment, the depth of the plateau, extending radially from the outer surface of the profile rib, is 1.50 mm to 3.00 mm. The chamfers can therefore be designed with such a surface area that edge curling is particularly effectively prevented, while simultaneously optimizing braking performance.

[0014] In another advantageous embodiment, the plateau has a constant width along its entire length. In this way, the chamfer's profile or its inclination relative to the radial direction can be particularly well adapted to the drainage effect of the cut.

[0015] Advantageously, the cut or cut section also has a radial width of 0.40 to 1.00 mm within the plateau, so that mutual support of the cut walls is ensured in this area of ​​the cuts or cut sections to stabilize the profile rib, for example during braking.

[0016] In a design where the plateau / chamfer combination is formed in a cut section, it is advantageous if a further cut section adjoins the cut section, which has cut walls that extend in a radial direction to the outer surface of the profile rib, continuing the cut walls of the first-mentioned cut section, so that the two cut sections together form a cut traversing the profile rib.

[0017] Further features, advantages, and details of the invention will now be described in more detail with reference to the schematic drawing, which illustrates an exemplary embodiment. This drawing shows... Fig. 1 a top view of a circumferential section of a profile rib of a tread of a vehicle pneumatic tire, Fig. 2 an enlarged section along line II-II of the Fig. 1 , Fig. 3 an enlarged section along line III-III of the Fig. 1 , Fig. 4 an enlarged section along line IV-IV of the Fig. 1 and Fig. 5 an enlarged section along line VV of the Fig. 1 .

[0018] Vehicle pneumatic tires designed according to the invention are in particular radial-type vehicle pneumatic tires for motor vehicles, preferably for passenger cars or light trucks.

[0019] Fig. 1 Figure 1 shows an example of a circumferential section of a profile rib 1 extending around the circumference of a tread of a vehicle tire, with an outer surface 1a and a width b1 (greatest axially determined width between the edge edges) at the outer surface 1a. The profile rib 1 is bounded on both sides by a circumferential groove 2, which in the example shown runs straight around the circumference and extends to the maximum tread depth TP specified for the respective tire type. Fig. 2 ) is executed. Further profile positives, for example additional profile ribs, adjoin the circumferential grooves 2; these are only indicated. Alternatively, the profile rib 1 is arranged on the shoulder side and is only bounded on one side by a circumferential groove 2, or it additionally has transverse grooves that create a block-like structure of the profile rib 1.

[0020] The profile rib 1 is structured by a multitude of incisions 3, which are in particular parallel to each other and largely straight or generally slightly curved, traversing the profile rib 1. The circumferential spacing of these incisions is on the order of 20.00 mm to 35.00 mm, and they extend at an acute angle to the axial direction, which is in particular up to 45°. In the embodiment shown, the incisions 3 have a constant or largely constant depth t 1 over their entire length. Fig. 3 ) from 60% to 95% of the TP tread depth.

[0021] How especially Fig. 1 As shown, the incisions 3, extending through the profile rib 1, consist of two incision sections 3a, 3b, a shorter incision section 3b and a longer incision section 3a.

[0022] The longer cut section 3a extends from the circumferential groove 2, into which it opens, at least to the middle region or the middle of the profile rib 1 and in particular over up to 80% of the width b 1 of the profile rib 1 determined in the axial direction on the outer surface 1a. As in particular Fig. 3 bis Fig. 5 As shown, the cut section 3a has a cut wall 5a extending radially from the cut base to the outer surface 1a of the profile rib 1. Opposite the cut wall 5a, extending from the cut base, there is another cut wall 5b at a distance that is, in particular, constant ( Fig. 3 ) of 0.40 mm to 1.00 mm to the cut wall 5a. The cut wall 5b ends at a particularly constant depth t 2, determined from the outer surface 1a, where the depth t 2 is 1.50 mm to 3.00 mm. At the radially outer end of the cut wall 5b, widening the cut section 3a, a narrow, strip-shaped plateau 6 adjoins, which extends over the entire extent of the cut section 3a and is oriented parallel to the outer surface 1a of the profile rib 1 and has a particularly constant width b 3 of 0.30 mm to 0.80 mm. In particular, the width b 3 of the plateau 6 is 0.10 mm to 0.20 mm less than the width b 2 of the cut section 3a, which corresponds to the aforementioned distance between the cut walls 5a, 5b ( Fig. 3 ).

[0023] Starting from the outer edge of the plateau 6, a chamfer 4 extends to the outer surface 1a of the profile rib 1. The chamfer 4 is an inclined surface with such an inclination relative to the radial direction that the cut section 3a ( Fig. 1 ) near the outer surface 1a of the profile rib 1, the chamfer 4 is widened again, with the inclination of the chamfer 4 changing along its length. At its end on the inner side of the profile rib, the chamfer 4 runs at its largest angle α relative to the radial direction (cf. Fig. 3 ), at its end on the circumferential groove 2, the chamfer 4 runs at its smallest angle α (cf. Fig. 5 At the end of the chamfer 4 on the inner side of the profile rib, the angle α is 20° to 60°, in particular 30° to 45°; at the end of the chamfer 4 on the side facing the circumferential groove, the angle α is at least 10° smaller and is 0° to 10°, in particular 0° to 5°. The plateau 6 can also run in the same direction as the chamfer 4 and be inclined at an angle of up to 70° to the radial direction.

[0024] Between the two ends of chamfer 4, the angle α changes continuously relative to the radial direction from the largest angle α at the end on the inside of the profile rib to the smallest angle α at the end on the side of the circumferential groove. Fig. 3 This is illustrated by a cross-section shown approximately in the middle of the cut section 3a. As a result, the cut section 3a, viewed at the outer surface 1a of the profile rib 1, has its greatest width at its end on the inside of the profile rib and its smallest width at the circumferential groove 2.

[0025] The shorter cut section 3b is bounded in the radial direction by two parallel cut walls, which extend from the cut section 3a as a continuation of the cut walls 5a, 5b and reach from the bottom of the cut to the outer surface 1a of the profile rib 1, so that the cut section 3b has the constant width b 2 of 0.40 mm to 1.00 mm, in particular up to 0.80 mm.

[0026] In an alternative design, cutouts are provided that are designed in the same way as the described cutout section 3a. These cutouts therefore end within the profile rib 1. Bezugszeichenliste

[0027] 1 Profile rib 1a Outer surface 2 Circumferential groove 3 Cut 3a, 3b Cut section 4 Chamfer 5a, 5b Cut wall 6 Plateau b 1 Width (Profile rib 1) b 2 Width (Cut) b 3 Width (Plateau 6) t 1 Depth (Cut) t 2 Depth (Plateau 6) TP Profile depth α Angle

Claims

1. Vehicle pneumatic tyre having a tread with at least one profile rib (1) which is of encircling form in a circumferential direction and is delimited on at least one side by a circumferential channel (2) and has an outer surface (1a) on the tread periphery and has sipes which extend in particular parallel to one another and at an angle of up to 45° to the axial direction, said sipes opening out into at least one circumferential channel (2) and ending within the profile rib (1), or having a sipe portion (3a) which opens out into the circumferential channel (2) and ends within the profile rib (1), wherein, over their extent, the sipe portions (3a) or the sipes ending within the profile rib (1) have in each case a sipe wall (5a) extending in the radial direction between the sipe base and the outer surface (1a) of the profile rib (1) and, opposite thereto, a further sipe wall (5b) extending likewise in the radial direction that is combined with a bevel (4), wherein the bevel (4) extends to the outer surface (1a) of the profile rib (1) and, when viewed in a cross-section of the respective sipe or sipe portion (3a), at an acute angle (α) to the radial direction, wherein, between the bevel (4) and the further sipe wall (5b), there is formed, extending preferably at a constant depth (t2) and preferably parallel to the outer surface (1a) of the profile rib (1), a plateau (6) having a width (b3) of 0.30 mm to 0.80 mm, wherein the angle (α) of the bevel (4) relative to the radial direction decreases continuously from its profile-rib-inner-side end to its circumferential-channel-side end, characterized in that the angle (α) which the bevel (4) includes with the radial direction at its circumferential-channel-side end is at least 10° smaller than the angle (α) which the bevel (4) includes with the radial direction at its profile-rib-inner-side end, wherein the sipe ending within the profile rib (1) or the sipe portion (3a) ending within the profile rib (1) extends, with respect to the width (b1) of the profile rib (1) determined at the outer surface (1a) in the axial direction, at least into the centre of the profile rib (1) and in particular over up to 80% of the width (b1) of the profile rib (1) determined at the outer surface (1a) in the axial direction.

2. Vehicle pneumatic tyre according to Claim 1, characterized in that the angle (α) which the bevel (4) includes with the radial direction at its profile-rib-inner-side end is 20° to 60°, in particular 30° to 45°.

3. Vehicle pneumatic tyre according to Claim 1 or 2, characterized in that the angle (α) which the bevel (4) includes with the radial direction at its circumferential-channel-side end is 0° to 10°, in particular 0° to 5°.

4. Vehicle pneumatic tyre according to one or more of Claims 1 to 3, characterized in that the depth (t2) at which the plateau (6) is situated in the radial direction when proceeding from the outer surface (1a) of the profile rib (1) is 1.50 mm to 3.00 mm.

5. Vehicle pneumatic tyre according to one or more of Claims 1 to 4, characterized in that the plateau (6) has a constant width (b3) over its extent.

6. Vehicle pneumatic tyre according to one or more of Claims 1 to 5, characterized in that the sipe or the sipe portion (3a) has a width (b2) of 0.40 mm to 1.00 mm radially within the plateau (6).

7. Vehicle pneumatic tyre according to one or more of Claims 1 to 6, characterized in that, in the case of sipes (3) having a sipe portion (3a) which opens out into the circumferential channel (2) and ends within the profile rib (1), the sipe portion (3a) is adjoined by a further sipe portion (3b) which has sipe walls extending as a continuation of the sipe walls (5a, 5b) of the former sipe portion (3a), albeit as far as the outer surface (1a) of the profile rib (1), so that the two sipe portions (3a, 3b) together form a sipe (3) that crosses through the profile rib (1).