VEHICLE TIRES

Description

[0001] The invention relates to a vehicle tire with at least one first and one second groove, wherein the first and the second groove are formed in a shoulder area of ​​the vehicle tire and run predominantly in the transverse direction, wherein at least one drainage groove running predominantly in the circumferential direction is arranged such that the drainage groove opens into an axially inner end of the first groove.

[0002] Tire treads differ, among other things, in the size of their negative volume, often also referred to as the void. A large negative volume is generally advantageous for the tire's performance in wet conditions, for example, to prevent aquaplaning. Conversely, a small negative volume is better suited to minimizing tire noise and thus complying with legal noise limits. Another potential disadvantage of a large negative volume, depending on the arrangement of grooves and sipes in the tire, can be reduced driving stability and a general deterioration of the tire's structural integrity. Despite numerous past efforts, creating tire treads that are both as stable and quiet as possible while also being optimally suited for wet roads remains a challenge.

[0003] DE 10 2014 225 621 A1 describes a pneumatic tire for vehicles, wherein a multitude of circumferentially spaced transverse grooves run in a shoulder-side tread band, with circumferentially extending drainage grooves opening into one end of the transverse grooves on the inside of the tread. This is intended to both facilitate the removal of water and ensure sufficient stability.

[0004] EP 3 169 536 A1 describes a tread strip having a profile band arranged at an outer shoulder, which is separated from further profile positives by a circumferential groove. The profile band contains circumferentially extending short grooves that are substantially aligned with and spaced apart from one another. At one end of each of these short grooves, a transverse groove extending towards and beyond the tread edge is formed, and at the other end of each of these transverse grooves, a transverse groove extending towards the circumferential groove is formed. EP 3 040 216 A1 describes a tire with a shoulder rib in which transverse grooves are formed that extend inwards from a tread edge without reaching a shoulder circumferential groove. First cuts connect the transverse grooves to the circumferential groove, and circumferentially extending cuts intersect the first cuts.EP 2 537 687 A1 describes a tire that includes, among other things, auxiliary grooves, wherein the auxiliary grooves comprise circumferential and lateral sections. JP 2017 170938 A describes a tire that includes, among other things, transverse grooves, circumferential grooves, and slits arranged in an outer shoulder. US 5 154 783 A describes a vehicle tire with a tread pattern comprising central tread block sections extending at an angle of 5° to 30° to an equatorial plane and forked end sections extending at an angle of 60° to 90° in the shoulder area. JP H04 224403 A describes a tread pattern with oblique grooves, slits extending through the oblique grooves, and auxiliary grooves.

[0005] The invention is based on the objective of further facilitating water drainage compared to the prior art by means of suitable structures, without impairing the stability of the vehicle tire and / or improving the stability without negatively affecting the tire's wet-weather performance. In particular, the conflicting objectives for a profile with a low overall negative volume are to be resolved at a high level, while achieving the lowest possible noise generation from the tire.

[0006] The object of the invention is solved by the features of claim 1 and, among other things, by the fact that the drainage groove extends from the first groove in a circumferential direction past an axially inner end of the second groove, wherein the drainage groove is not connected to the second groove.

[0007] Contrary to expectations, the invention succeeds in arranging particularly long, primarily circumferentially extending drainage grooves on a tire tread compared to the prior art, without arranging the drainage grooves in a continuous circumferential groove and without providing additional intersections and / or junctions in grooves that primarily run transversely. It turns out that the arrangement according to the invention is capable of contributing to particularly good results in wet handling while simultaneously limiting noise generation and without compromising driving stability.

[0008] The directional terms axial, radial, and circumferential refer to the vehicle tire as intended on a vehicle and its rolling motion. The circumferential direction describes the direction of rolling motion around the axis of rotation. When the vehicle is moving forward, a tire positioned at the front circumferentially reaches its minimum distance to the road surface earlier during a 360° rotation than a tire positioned at the rear circumferentially. The rear position reaches its minimum distance to the road surface less than 180° behind the front position. The radial direction refers to a direction perpendicular to and intersecting the vehicle tire's axis of rotation. "Radially inward" refers to the orientation that faces the radial axis of rotation.Radially outward refers to the orientation that points away from the axis of rotation in the radial direction. The axial direction refers to a direction parallel to the axis of rotation. Axially inward refers to an orientation that points axially toward a tire equator plane or tire equator line. The tire equator plane is a plane perpendicular to the vehicle tire's axis of rotation that passes through the center of the tire's axial width, with the tire equator line lying in the tire equator plane and on the tire's surface. The transverse direction is defined as a direction consisting of components of the radial and / or axial directions.

[0009] In particular, a transverse direction can run along a base surface of the vehicle tire and be perpendicular to the circumferential direction. The base surface coincides with the smooth surface that the vehicle tire would have if no negative or positive tread elements, such as grooves or projections, were present. Specifically, the base surface remains physically intact wherever no such tread elements are present. The remaining portions of the base surface can be at least partially intended for contact with a road surface. For example, where a groove runs through a tread of the vehicle tire, the base surface continues as an imaginary area above the groove; where, for example, a projection is arranged on the tread, the base surface continues as an imaginary area below the projection.

[0010] A straight line is predominantly oriented in a first direction if a dominant directional component of the line points in that first direction. This is true when the angle between the line and the first direction is less than 40°, preferably less than 30°. A profile feature that is predominantly oriented in a first direction, such as a groove or a drainage channel, can be described by a straight line that is predominantly oriented in the first direction, where the line can be a regression line through a point cloud of all points belonging to the profile feature. The points belonging to a profile feature fill a volume between the base surface and the physical surface of the vehicle tire, with each point having a vanishing distance to at least one other point from the point cloud of the profile feature.In the case of a negative profile feature such as a groove or a channel, the points belonging to the profile feature can lie below the base surface and above the physical surface of the vehicle tire. The contours of the profile feature on the base surface can run at a constant distance from the straight line and / or move away from or closer to the straight line by means of curves and / or kinks. The distance of the contours from the straight line is preferably less than 50%, and more preferably less than 10%, of the greatest distance between two points in the profile feature.

[0011] The effects achieved with the features of the main claim are further enhanced and supplemented by preferred embodiments and configurations of the grooves and the drainage groove as well as the opening of the drainage groove into the first groove.

[0012] A particularly preferred embodiment is one in which the drainage groove extends past the second groove at an axial distance of 2 mm to 8 mm. This extension distance is measured as the shortest axial distance between the radially outer edges of the drainage groove and the second groove at the base surface of the vehicle tire. This axial distance between the drainage groove and the second groove ensures both efficient use of the space on the vehicle tire and sufficient stability of any remaining rib between the drainage groove and the second groove within the area of ​​this axial distance.

[0013] The first groove, the second groove, and the drainage groove are formed within a shoulder-side profile band, the shoulder-side profile band being separated from a central profile band by a circumferential groove. An axial gap may be provided between the second groove and the circumferential groove, with the drainage groove extending past the second groove in an axially centered area of ​​less than 25% of the axial gap. In other words, the drainage groove can be located approximately in the middle, preferably exactly in the middle, between the circumferential groove and the axially inner end of the second groove, measured along the axial direction. This symmetry ensures sufficient rib width on both sides of the drainage groove to the adjacent grooves, maintaining a high level of structural integrity in the vehicle tire.

[0014] The first and second grooves can be spaced between 20 mm and 50 mm circumferentially, preferably between 25 mm and 40 mm. This circumferential distance is measured as the shortest circumferential distance between the radially outer edges of the grooves on the base surface of the vehicle tire.

[0015] The drainage groove can extend circumferentially past the second groove by a length of between 1% and 99%, preferably between 5% and 25%, of the circumferential distance between the first and second grooves. This achieves a good compromise between the longest possible drainage groove for improved wet performance and the largest possible continuous tread area behind the second groove for structural integrity and advantageous dry performance of the tire.

[0016] The drainage groove can have a groove depth of 1.5 mm to 3 mm over a large portion of its extent. The groove depth can be defined as the greatest depth along a width of the drainage groove, where the width can be defined along the shortest width of the drainage groove at each position along the length of the drainage groove. The drainage groove can then have the specified depth over a large portion of its extent if the groove depth is present at a large proportion of positions along the length of the drainage groove, for example, more than 50%. The drainage groove can have a groove depth of 5% to 75%, preferably 15% to 30%, of the groove depth of the first groove. The groove depth can be defined analogously to the groove depth. The groove depth and / or the groove depth can vary along their length.In this case, the depths used for comparison can be the average groove depth and the average slot depth along the longitudinal extents of the first groove and the drainage slot, respectively. According to one embodiment of the invention, the drainage slot has a decreasing slot depth along its extent, with the slope preferably running from a tip of the drainage slot, towards the first groove, from a smaller slot depth to a larger slot depth. Preferably, there is a minimum slot depth at the tip of the drainage slot and a maximum slot depth at the opening into the first groove; if the opening is via a connecting section between the first groove and the drainage slot, the maximum slot depth can be located at the transition into the connecting section. The slope can be present over part or all of the lateral extent of the drainage slot.In one embodiment, the slope lies between the tip of the drainage groove and a position shifted from the tip by 10% to 50% of the groove's length towards the first groove. The slope can be constant or variable. In another embodiment, the groove depth increases from a minimum depth with a maximum absolute slope, whereby the slope decreases with increasing depth and can be essentially flat in the region of maximum depth. The described selection of the groove depth achieves a good compromise between a positive effect on wet-weather performance through high negative volume on the one hand, and the least possible negative effect on the structural integrity and noise generation of the vehicle tire on the other.Furthermore, the design of the gradient can be used to optimize the flow characteristics and the drainage function of the drainage groove.

[0017] The drainage groove and the first groove can be connected by a laterally rounded connecting section, i.e., along the base surface. In particular, the drainage groove and the first groove, or the respective straight lines describing their extent, can form an angle, the angle being bridged by a circular segment or an approximation thereof. The first groove and / or the drainage groove can preferably connect to the connecting section continuously, i.e., tangentially, in the first derivative. The rounded connecting section can be defined by an outer radius between 1 mm and 10 mm, where the outer radius is larger than an inner radius and, together with the inner radius, describes the contours of the rounded connecting section on the base surface of the vehicle tire.

[0018] A transition zone in depth between the drainage groove and the first groove can have a lateral transition extent of 0.5 mm to 10 mm, preferably 2 mm to 5 mm. In other words, the depth can change over a transition, a few millimeters long and correspondingly steep, along the base surface as described. Alternatively or additionally, the transition extent can run primarily in the transverse direction. In this case, the transition zone between the two different depths, namely the depth of the drainage groove and the depth of the first groove, can begin directly adjacent to the rounded connecting section between the drainage groove and the first groove and extend into the first groove.

[0019] The described lateral and depth-related designs of the connection point or transition area between the drainage groove and the first groove allow for a good compromise between advantageous flow behavior, good structural integrity and an aesthetically pleasing appearance.

[0020] The drainage groove can have a decreasing width along its length, with its greatest width at its opening into the first groove. If the opening is via a connecting section between the first groove and the drainage groove, the drainage groove can have its greatest width at the transition into this connecting section. The width of the drainage groove is measured at the base of the vehicle tire and as the shortest distance at each position along the lateral extent of the drainage groove. The maximum groove width can be between 1 mm and 5 mm, preferably between 2 mm and 4 mm. The described width and its profile enable particularly effective drainage from the drainage groove area into the first groove.

[0021] The first and second grooves can run parallel to each other along a large part of their extent. The grooves are particularly parallel if the circumferential contours of the grooves, which point in the same orientation, are parallel on the base surface; for example, if a contour of the first groove on a circumferentially leading side is parallel to a contour of the second groove on a circumferentially leading side. Preferably, the two grooves can run parallel to each other along at least 50% of the lateral extent of their contours on the base surface.

[0022] The first groove and / or the second groove can run along a large part of their extent at a groove angle of 70° to 90°, preferably at a groove angle of 85° to 90° to the circumferential direction. A groove runs along a large part of its extent at a specific angle if a continuous portion of the point cloud constituting the groove can be described by a regression line running at that specific angle, wherein the continuous portion comprises more than 50%, preferably more than 67%, of the points from the point cloud of the groove. The first and / or the second groove can, in particular, terminate at their axially outer ends in a direction deviating from the specified angular ranges and, in particular, bend or curve in the circumferential direction.

[0023] The drainage groove can extend along a large part of its length at a groove angle of 0° to 40°, preferably at a groove angle of 5° to 15° to the circumferential direction, with the angle being axially inward of the circumferential direction. The definition of a drainage groove extending along a large part of its length at a specific angle can be analogous to the definition relating to a groove. The angle of the drainage groove opens axially inward from the circumferential direction, so that the drainage groove can extend from its opening into the first groove along its circumferential length to the second groove and, in particular, further axially inward beyond. In this way, the drainage groove can be located axially further outward at its opening into the first groove than as it extends past the second groove.This is particularly advantageous if, as in a preferred embodiment, the first and second grooves terminate at their axially inner ends with the same width. On the other hand, the groove angle should be small enough, and the drainage groove thus run close enough to the circumferential direction, to exploit the advantages associated with the circumferential direction in terms of noise reduction.

[0024] The first groove and the drainage channel can form an angle between 90° and 170°, preferably between 95° and 105°. This angle can open circumferentially and axially outwards. This achieves a good compromise between efficient use of the profile surface and optimal functionality of the grooves and drainage channel.

[0025] The first groove, the second groove, and the drainage groove can form a first group of profile elements, wherein at least one further group is formed on the vehicle tire according to the pattern of the first group, i.e., comprising two grooves and a drainage groove in the arrangement according to the invention. The further group can be arranged circumferentially offset from the first group. If several groups are arranged in succession in this manner, an AB pattern can result, with a drainage groove extending axially inside every second groove, originating from a circumferentially adjacent groove. The grooves of the first and further groups can be arranged at uniform intervals along the circumferential direction or follow one another at varying intervals within a suitable pitch sequence.

[0026] The invention is described below by way of example with reference to the accompanying drawings and advantageous embodiments. The drawings show: Figure 1 schematically a perspective view of a vehicle tire with arrangements of grooves and drainage channels according to an embodiment of the invention, Figure 2 a top view of a group of grooves with a drainage channel according to an embodiment of the invention, Figure 3 one extending longitudinally through the first groove and the drainage groove according to Figure 2 corresponding sectional view.

[0027] Vehicle tires designed according to the invention are tires of any construction, in particular radial tires, and tires of any type, in particular pneumatic tires for motor vehicles such as passenger cars, light trucks, or commercial vehicles. However, the invention can also be advantageously applied to vehicle tires for vehicles with an odd number of tires, for example, for motorcycles.

[0028] Figure 1Figure 1 schematically shows a perspective view of a vehicle tire 1. On a shoulder area 4, transverse grooves 2, 3 are arranged at substantially similar intervals along the circumferential direction. At the axially inner end of every second groove 3, a drainage groove 5 extends circumferentially, the drainage groove 5 originating from a circumferentially adjacent first groove 2. A first and second groove 2, 3 together with a drainage groove 5 can be described as a first group 20. According to the embodiment shown, a further group 21, substantially identical to the first group, is formed circumferentially offset from the first group 20 on the shoulder area 4 of the vehicle tire. By arranging several substantially identical groups 20, 21 in succession, an AB tread pattern can be formed on the tire shoulder as shown.

[0029] Figure 2schematically shows a top view of one of the first group 20 from Figure 1 A substantially similar arrangement according to one embodiment of the invention. An axially outer edge of a shoulder-side profile band 4a is shown at the right edge of the drawing. A circumferential groove 7 is indicated at the left edge as a boundary to a central profile band 8. Between these extend a first groove 2, a second groove 3, and a drainage groove 5.

[0030] The first and second grooves 2, 3 run essentially in the axial direction and are spaced apart from each other by a circumferential distance 10. The drainage groove 5 extends circumferentially by a passing length 17 and axially by a passing distance 6 past the second groove 3. The first groove 2 transitions into the drainage groove in a connecting section 13. The connecting section 13 can be described by an outer radius 14.

[0031] The drainage groove 5 has its greatest width 18 at its transition into the connecting section 13 and narrows along its circumferential extent. The longitudinal extent of the drainage groove 5 runs essentially along a straight line that deviates inwards from the circumferential direction at a groove angle 19 in the axial direction. The groove angle 19, in conjunction with the circumferential distance 10 between the two grooves 2, 3 and an axial gap 9 between the second groove 3 and the circumferential groove 7, is dimensioned such that the drainage groove 5 extends past the second groove 3 essentially in the middle of the axial gap 9.

[0032] In Figure 2The lateral course of a maximum depth per width extent along a length extent through the drainage groove 5, the connecting section 13 and the first groove 2 is marked by a dashed line running through the aforementioned profile elements. Figure 3 Figure 1 schematically shows a section through the profile of the vehicle tire along this dashed line. Accordingly, the groove depth 15 is smaller than the groove depth 16 of the first groove 2. The transition between the two depths takes place in a transition zone 11, which has a lateral transition extent 12. As shown in Figure 2 As indicated, the transition area connects directly to the connecting section 13, with the transition extension 12 running essentially in the axial direction into the first groove 2. Reference symbol list

[0033] 1 Vehicle tire 2 First groove 3 Second groove 4 Shoulder area 4a Shoulder-side profile band 5 Drainage groove 6 Pre-extension distance 7 Circumferential groove 8 Middle profile band 9 Axial gap 10 Circumferential distance 11 Transition area 12 Transition extension 13 Connecting section 14 Outer radius 15 Groove depth 16 Groove depth 17 Pre-extension length 18 Groove width 19 Groove angle 20 First group 21 Further group

Claims

1. Vehicle tyre (1) having at least one first and one second groove (2, 3), wherein the first and the second groove (2, 3) are formed in a shoulder region (4) of the vehicle tyre (1) and run predominantly in the transverse direction, wherein a groove (2, 3) running predominantly in the transverse direction runs at an angle of less than 40° with respect to the transverse direction, wherein at least one drainage groove (5) running predominantly in the circumferential direction is disposed in such a way that the drainage groove (5) opens into an axially inner end of the first groove (2), wherein the first groove (2), the second groove (3) and the drainage groove (5) are formed in a shoulder-proximal profile strip (4a), wherein the shoulder-proximal profile strip (4a) is separated from a central profile strip by a circumferential groove (7), characterized in that the drainage groove (5) extends from the first groove (2) in the circumferential direction past an axially inner end of the second groove (3), wherein the drainage groove (5) is not connected to the second groove (3), wherein the drainage groove (5) is not disposed in a continuously encircling groove and without additional intersections and / or openings at grooves running predominantly in the transverse direction.

2. Vehicle tyre according to Claim 1, characterized in that the drainage groove (5) extends past the second groove (3) at an axial passing spacing (6) of 2 mm to 8 mm.

3. Vehicle tyre according to either of Claims 1 and 2, characterized in that the first groove (2), the second groove (3) and the drainage groove (5) are formed in a shoulder-proximal profile strip (4a), wherein the shoulder-proximal profile strip (4a) is separated from a central profile strip (8) by a circumferential groove (7), wherein an axial intermediate space (9) lies between the second groove (2) and the circumferential groove (7), and wherein the drainage groove (5) extends past the second groove (3) in a region which is axially centred about the centre of the axial intermediate space (9) and is less than 25% of the axial length of the axial intermediate space (9).

4. Vehicle tyre according to one of Claims 1 to 3, characterized in that the first and the second groove (2, 3) are mutually spaced apart in the circumferential direction by a circumferential spacing (10) between 20 mm and 50 mm, preferably between 25 mm and 40 mm.

5. Vehicle tyre according to one of Claims 1 to 4, characterized in that the drainage groove (5) extends past the second groove (3) in the circumferential direction by a passing length (17) of between 1% and 99%, preferably between 5% and 25%, of the circumferential spacing (10) between the first and the second groove (2, 3).

6. Vehicle tyre according to one of Claims 1 to 5, characterized in that the drainage groove (5) has a groove depth (15) of 1.5 mm to 3 mm over a majority of its extent and / or in that the drainage groove (5) has a groove depth (15) of 5% to 75%, preferably of 15% to 30%, of a groove depth (16) of the first groove (2).

7. Vehicle tyre according to one of Claims 1 to 6, characterized in that a transition region (11) in the depth between the drainage groove (5) and the first groove (2) has a lateral transition extent (12) with a length of 0.5 mm to 10 mm, preferably of 2 mm to 5 mm, and / or in that the lateral transition extent (12) runs predominantly in the transverse direction.

8. Vehicle tyre according to one of Claims 1 to 7, characterized in that the drainage groove (5) and the first groove (2) are connected to one another by way of a laterally radiused connecting portion (13), wherein the radiused connecting portion (13) is defined by an external radius (14) of between 1 mm and 10 mm.

9. Vehicle tyre according to one of Claims 1 to 8, characterized in that the drainage groove (5) has a groove width (18) which decreases over its extent, wherein it has its greatest groove width (18) at its mouth to the first groove (2), wherein the greatest groove width (18) is preferably between 1 mm and 5 mm, more preferably between 2 mm and 4 mm.

10. Vehicle tyre according to one of Claims 1 to 9, characterized in that the first and the second groove (2, 3) run parallel to one another along a majority of their extent.

11. Vehicle tyre according to one of Claims 1 to 10, characterized in that the first and / or the second groove (2, 3) run along a majority of their extent at a groove angle of 70° to 90°, preferably at a groove angle of 85° to 90°, with respect to the circumferential direction.

12. Vehicle tyre according to one of Claims 1 to 11, characterized in that the first and the second groove (2, 3) at their axially inner ends terminate axially at the same width.

13. Vehicle tyre according to one of Claims 1 to 12, characterized in that the drainage groove (5) extends along a majority of its lateral extent, that is to say extends along a base surface of the vehicle tyre (1), at a groove angle (19) of 0° to 40°, preferably at a groove angle (19) of 5° to 15°, with respect to the circumferential direction, wherein the groove angle (19) bears axially within the circumferential direction.

14. Vehicle tyre as according to one of Claims 1 to 13, characterized in that the first groove (2) and the drainage groove (5) include an inclusion angle between 90° and 170°, preferably between 95° and 105°.

15. Vehicle tyre according to one of Claims 1 to 14, characterized in that the first groove (2), the second groove (3) and the drainage groove (5) form a first group (20), wherein formed on the vehicle tyre (1) is at least one further group (21) according to the pattern of the first group (20) with two grooves (2, 3) and one drainage groove (5), wherein the further group (21) is disposed so as to be displaced in the circumferential direction with respect to the first group (20).