Vehicle pneumatic tire with circumferential grooves

Abstract

A tire has a tread (2) with at least one circumferential groove (1) having a first cross section and a second cross section in an alternating manner over a partial segment (21, 24) of the tire circumference, perpendicular to the circumferential direction. The first cross section is composed of at least two groove portions adjoining one another in a first radial direction R1 of the vehicle pneumatic tire, a first groove portion (3) symmetrical with respect to the first radial direction R1 and a second groove portion (4) extending axially inside with respect to the first groove portion. The second cross section is composed of at least two groove portions adjoining one another along a second radial direction R2 of the vehicle pneumatic tire and symmetrical with respect to the radial direction R2, a first groove portion (33) widening outwards and a second groove portion (34) inside narrowing with respect to the first groove portion.

Description

Technical Field

[0001] The present invention relates to a vehicle pneumatic tire having a tread pattern and at least one circumferential groove extending in a circumferential direction and forming to a tread depth PT, and having alternating first and second cross sections perpendicular to the circumferential direction on a portion of the circumference of the vehicle pneumatic tire over the entire tire circumference. Background Technology

[0002] It is known and customary to provide circumferential grooves extending in a circumferential direction on the tread of pneumatic tires for multi-purpose vehicles. Such circumferential grooves separate circumferential ribs, which may have additional grooves (e.g., lateral grooves) that give the circumferential ribs a block-like structure.

[0003] The structure of circumferential grooves is defined by a cross-section perpendicular to the circumferential direction. This cross-section may be the same across the entire circumference of the pneumatic tire, or it may differ in different sections of the circumference.

[0004] Circumferential grooves, which have only one groove portion on a cross section perpendicular to the circumferential direction of the vehicle's pneumatic tire, are commonly found in the tread of vehicle pneumatic tires. However, the cross section may also have multiple groove portions, which are then preferably adjacent to each other along the radial direction R of the vehicle's pneumatic tire.

[0005] In a tire, the radial direction R is a direction perpendicular to the tire's axis of rotation and pointing outwards. This axis of rotation defines the tire's axial direction A, which is either the center of the tire or the center of the hub supporting the tire's rim. In this direction, when a wheel equipped with a multi-purpose vehicle pneumatic tire rotates, centrifugal force acts on the tire.

[0006] The distinguishing feature of a circumferential groove is the specific geometry of its cross-section perpendicular to the tire's circumferential direction, which is distinctly different from the geometry of another groove's cross-section perpendicular to the tire's circumferential direction. Therefore, if a circumferential groove has only one groove portion, its cross-section perpendicular to the tire's circumferential direction can be described geometrically. A circumferential groove with only one groove portion has, for example, a V-shaped or U-shaped cross-section perpendicular to the tire's circumferential direction.

[0007] The cross-section of the groove portion perpendicular to the tire circumferential direction is defined by two side surfaces in the axial direction A. These side surfaces, almost parallel or exactly parallel to the radial direction R, give the groove portion a U-shaped profile. In this groove portion, the tangents of the side surfaces perpendicular to the circumferential direction form an angle of no more than 10° with the radial direction. Specifically, the tangents may extend parallel to the radial direction.

[0008] On the other hand, if the two sides of the groove portion with increasing groove depth approach each other at an angle greater than 10° relative to the radial direction R as the depth of the circumferential groove increases, then the groove portion has a V-shaped cross section.

[0009] However, the cross-section of a circumferential groove perpendicular to the circumferential direction can also be composed of multiple groove portions adjacent to each other in the radial direction R. Here, each groove portion can be symmetrical about the radial direction.

[0010] The following are known circumferential grooves in the tread of a vehicle pneumatic tire, which have a first section and a second section perpendicular to the circumferential direction in an alternating manner in a portion of the circumference of the vehicle pneumatic tire, wherein one or both sections are composed of two or more groove portions adjacent to each other in the radial direction R.

[0011] In the known form of this circumferential groove 1 in the tread 2 of a vehicle's pneumatic tire, it is in Figure 1 The figure illustrates, as an example and primarily used for, the inner circumferential grooves in the central region of the tread of a vehicle pneumatic tire. The first cross-section shown, perpendicular to the circumferential direction, has a first groove portion 3 symmetrical about the radial direction R1 of the vehicle pneumatic tire (indicated by arrow R1 in the figure). This groove portion has a constant width B in the axial direction A of the vehicle pneumatic tire (also indicated by arrow A in the figure). v,1 The side of the grooved portion extends parallel to the radial direction R1. Therefore, the first grooved portion has a U-shaped cross-section.

[0012] The first groove portion 3 is adjacent to the second groove portion 4 in the radial direction R1 (opposite to the direction of the arrow). The groove portion 4 has a cross-section that is wider than the first groove portion 3 in the axial direction A, and is the innermost groove portion of the circumferential groove, which also includes the groove bottom of the cross-section shown for the circumferential groove 1. The second groove portion 4 is also symmetrical about the radial direction R1.

[0013] in addition, Figure 1The first cross-section shown has an outer third groove portion 5, which is perpendicular to the circumferential direction of the circumferential groove 1 and terminates on the surface of the tread 2 of the vehicle's pneumatic tire. The cross-section of the third groove portion 5 widens outward in the radial direction R1 and symmetrically with respect to the radial direction R1 of the vehicle's pneumatic tire, and therefore the width of the third groove portion in the axial direction A is greater than the width B of the first groove portion 3. V,1 Continue increasing up to the surface of tread 2 until width B V,O .

[0014] The second cross section of this known form of circumferential groove 1 has only one groove portion with an open V-shaped cross section.

[0015] Compared to other cross sections, Figure 1 The first cross-section of the known form of the circumferential groove shown exhibits reduced rolling resistance. This is based on the structure of the first groove portion. The maximum width of the first groove portion in the axial direction A is 3 mm. The small width of the first groove portion in the axial direction ensures lateral contact of the first groove portion when the cross-section of the circumferential groove contacts the road due to vehicle weight, which compresses the tread rubber material. As a result, further deformation of the tread rubber material in this region of the circumferential groove is prevented, especially further deformation in the axial direction A. This significantly reduces the rolling resistance of the vehicle's pneumatic tire. Additionally, in this region, the width B of the circumferential groove on the tread surface... V,O The reduction in the tread surface area, the increase in the supporting surface area of ​​the tread, and the contact of the groove sides lead to a decrease in the contact pressure on the tread surface, which reduces tire wear.

[0016] On the other hand, the behavior of the compressed second groove portion in wet environments, especially braking behavior in wet environments, is initially unfavorable in new tires and only improves as tire wear increases. As a result, the widened second groove portion can then be used as a reservoir for absorbing water from the road.

[0017] To compensate for this, the second section of the circumferential groove has only one groove portion with an open V-shaped cross-section. The advantage of this cross-section in the circumferential groove is its excellent braking performance in wet conditions. Because the two cross-sections in the circumferential groove now alternate across a portion of the circumference of the vehicle's pneumatic tire, both reduced rolling resistance and good braking performance in wet conditions can be achieved simultaneously through the circumferential groove. Nevertheless, this circumferential groove achieves only a compromise, sacrificing some characteristics in both areas.

[0018] Details of a very similar embodiment of this circumferential groove with very similar properties are described in DE 10 2015 215 455 A1.

[0019] Another embodiment of circumferential grooves in the tread of a pneumatic tire for a vehicle is known from WO 2017 / 174925 A1, wherein this other embodiment... Figure 6 As an example of the described invention, these circumferential grooves have alternating first and second cross-sections perpendicular to the circumferential direction in certain sections of the circumference of the pneumatic tire of the vehicle, wherein the two cross-sections are composed of a plurality of groove portions adjacent to each other in the radial direction R. In the first cross-section, there is first a groove portion with a constant width on the tread surface, which is radially adjacent to another second groove portion, the width of which steadily widens inward to a maximum width in the axial direction A. On the other hand, in the second cross-section, there is a first groove portion, the cross-section of which continuously widens outward perpendicular to the circumferential direction and terminates in a wide groove portion with a constant width in the axial direction A, which is located on the surface of the tread. The first groove portion is radially adjacent to another small groove portion, which has a small constant width at a small height in the radial direction R exceeding the tread wear limit. A key feature of the circumferential grooves shown is that the height of the second groove portion in the radial direction R of the first section and the height of the first groove portion in the radial direction R of the second section significantly comprise the tread depth of the circumferential grooves. As a result, a continuous circumferential channel exists between the two adjacent groove portions in the two sections, allowing fluid drainage to occur within the circumferential grooves between the two sections. Because the first groove portion in the second section comprises most of the tread depth of the circumferential grooves, the stability and stiffness of this groove portion only increase after the outer groove portion with a constant width and a considerable portion of the first groove portion have worn due to tire abrasion (resulting in a reduction in the width of the circumferential grooves on the tire surface). Therefore, due to the profile of the second section, rolling resistance is only improved in the region of the second section after the tire has been used for a relatively long period.

[0020] Similarly, another embodiment of circumferential grooves in the tread of a pneumatic tire is known from US 2020 / 0164694 A1. These circumferential grooves have alternating first and second cross sections perpendicular to the circumferential direction in a partial section along the entire circumference of the pneumatic tire, wherein the two cross sections are composed of a plurality of groove portions adjacent to each other in the radial direction R. In the first cross section, a groove portion of constant width is initially present on the tread surface, which radially abuts another second groove portion, the width of which in the axial direction A first widens with increasing distance from the tread surface and then decreases again. On the other hand, in the case of the second cross section, there is a first groove portion whose cross section continuously widens outward in the circumferential direction until the tread surface. The first groove portion radially abuts a second smaller groove portion, which has a small constant width at a small height in the radial direction R. Compared to the height of the second groove portion along the radial direction of the first section, this portion has a smaller height in the radial direction. In the second section, the second groove portion is inwardly adjacent to the third groove portion, the width of which in the axial direction A widens again with increasing distance from the tread surface. As a result, there is a continuous circumferential channel between the second groove portion of the first section and the first and third groove portions of the second section in the two circumferentially adjacent sections, allowing liquid discharge to occur between the two groove sections within the circumferential groove. Because the length of the second groove portion in the second section is very short, the stability and stiffness of the circumferential groove are improved only to a limited extent in this second section. The sides of the circumferential groove are actually compressed in the region of the second groove portion, but due to the small area of ​​the adjacent sides, the rubber material may still yield to the forces acting upon it and deform when the second section of the circumferential groove comes into contact with the road, especially through the third groove portion in the radial direction. Therefore, circumferential grooves still exhibit considerable rolling resistance in the region with the second cross section. Summary of the Invention

[0021] The present invention is based on the purpose of providing circumferential grooves for vehicle pneumatic tires, which continue to have good wet properties as a safety feature, and the rolling resistance of the circumferential grooves is further reduced, thereby achieving further fuel savings and thus improving the CO2 balance of vehicles equipped with vehicle pneumatic tires.

[0022] This objective is achieved by the pneumatic tires for vehicles, particularly multi-purpose vehicle tires, of the present invention.

[0023] This type of pneumatic tire is a pneumatic tire having a tread pattern and at least one circumferential groove. The circumferential groove extends in a circumferential direction and extends to a tread depth PT. The circumferential groove has alternating first and second sections perpendicular to the circumferential direction on a portion of the circumference of the entire tire. The first section is formed by at least two adjacent groove portions along a first radial direction R1 of the pneumatic tire – a first groove portion and a radially inner second groove portion. The first groove portion is symmetrical about the first radial direction R1, and its width along the axial direction A of the pneumatic tire is less than 3. The width of the second groove portion is mm and varies by no more than 10%, preferably no more than 2%, and particularly preferably no more than 0.5%. The second groove portion on the radially inner side is wider than the first groove portion in the axial direction A and has the largest cross-sectional area among all groove portions. The second groove portion on the radially inner side is also preferably symmetrical about the first radial direction R1. The second cross-section is composed of at least two groove portions that are adjacent to each other along the second radial direction R2 of the vehicle's pneumatic tire and symmetrical about the radial direction R2: a first groove portion that widens outwards and an inner second groove portion that is narrower than the first groove portion. The width B of the inner second groove portion... Y,2 The variation along the axial direction A of the vehicle's pneumatic tire is no greater than 10%, preferably no greater than 2%, particularly preferably no greater than 0.5%, and the width of the second groove portion on the inner side is less than the width B of the second section on the tread surface in the axial direction A when the vehicle's pneumatic tire is new. Y,O The height H2 of the second groove portion of the second cross section in the radial direction R2 of the first cross section in the radial direction R1 is 40%, preferably less than 30%, particularly preferably less than 25%. v Extending over at least 50% of the second groove portion of the second cross section, and at a height H2 in the radial direction R2. Y At least 50% of the second groove portion of the second cross section is at a certain distance from the surface of the tread, and the second groove portion is located in the first cross section at this distance.

[0024] The pneumatic tire of the present invention has a tread with a pattern. The tread includes at least one circumferential groove along the circumferential direction of the pneumatic tire. The circumferential groove extends in a circumferential manner and is formed to a tread depth PT. Correspondingly, each of these circumferential grooves has a tread depth PT over the entire circumference of the tire, but different circumferential grooves may have different tread depths PT.

[0025] The circumferential grooves forming the tread depth PT thus have the same tread depth across the entire tire circumference, at least when the tire is new, with a tolerance typically between 0.10 mm and 0.15 mm, the tolerance being solely due to manufacturing processes. The tread depth will only deviate from the height of the tread wear indicator at these points if a tread wear indicator is present in the circumferential grooves. For example, the height of the tread wear indicator can be 1.2 mm. As an example of a tread wear indicator, transverse grooves are evenly distributed at the bottom of the grooves in the circumferential grooves along the tire circumference.

[0026] At least one of these circumferential grooves in the tread pattern has a first section and a second section that are perpendicular to the circumferential direction of the vehicle's pneumatic tire, alternating over the entire tire circumference and in a portion of the circumference of the vehicle's pneumatic tire.

[0027] The first section perpendicular to the circumferential direction of the vehicle's pneumatic tire is composed of at least two groove portions adjacent to each other along the first radial direction R1 of the vehicle's pneumatic tire - the first groove portion and the second groove portion.

[0028] The first groove portion is symmetrical about a first radial direction R1. The first radial direction R1 is defined here due to the symmetry of the cross-section of the first groove portion perpendicular to the circumferential direction. The width of the first groove portion along the axial direction A of the vehicle's pneumatic tire is less than 3 mm. This width variation is no greater than 10%, preferably no greater than 2%, and particularly preferably no greater than 0.5%. However, in a very advantageous embodiment, the width of the first groove portion can also be constant. Deviations in the width of the first groove portion exceeding this width are then attributed solely to limitations in the production of the circumferential grooves. The resulting tolerance in the width of the first groove portion is typically less than 0.2 mm, preferably less than 0.15 mm, and particularly preferably less than 0.05 mm.

[0029] The second groove portion of the first cross-section of the circumferential groove is arranged radially inward relative to the first groove portion. That is, the second groove portion directly adjoins the first groove portion in the radial direction R1. The second groove portion is arranged closer to the center of the tire, and conversely, the second groove portion is farther from the tread surface than the first groove portion. Furthermore, the second groove portion of the first cross-section is wider than the first groove portion in the axial direction A. In other words, the width of the second groove portion in the axial direction A is greater than the maximum width of the first groove portion. Preferably, the width of the second groove portion in the axial direction A is greater than the maximum width of the first groove portion over a larger range in the first radial direction R1 or over a larger area of ​​the distance of the circumferential groove from the tread surface (the depth of the circumferential groove). Typically, the width of the second groove portion in the axial direction A is greater than the maximum width of the first groove portion over a range of at least 3 cm, preferably at least 4.5 cm, and particularly preferably at least 5.5 cm in the radial direction R1. Furthermore, typically, for at least 50% of the maximum range of the second groove portion in the radial direction R1, preferably for at least 75% of the maximum range of the second groove portion in the radial direction R1, and particularly preferably for at least 90% of the maximum range of the second groove portion in the radial direction R1, the width of the second groove portion in the axial direction A is greater than the maximum width of the first groove portion. Additionally, the second groove portion of the first cross-section of the circumferential groove perpendicular to the circumferential direction of the vehicle's pneumatic tire has the largest cross-sectional area perpendicular to the circumferential direction among all groove portions of the first cross-section.

[0030] In a preferred embodiment, the second groove portion of the first cross section of the circumferential groove is also symmetrical about the first radial direction R1.

[0031] The second section of the circumferential groove, perpendicular to the circumferential direction of the vehicle's pneumatic tire, is also composed of at least two adjacent groove portions—a first groove portion and a second groove portion—along the second radial direction R2 of the vehicle's pneumatic tire. Both groove portions are symmetrical about the radial direction R2.

[0032] The first groove portion of the second section perpendicular to the circumferential direction widens outward. That is, as the distance from the surface of the tire tread decreases, or as the depth of the circumferential groove decreases, the width of the groove portion in the axial direction A increases.

[0033] The second groove portion of the second cross-section, perpendicular to the circumferential direction, is narrower and located inside the first groove portion of the second cross-section. That is, the width of the second groove portion in the axial direction A is no greater than the minimum width of the first groove portion in the axial direction A. Since the first groove portion widens outwards, this minimum width is the case where the first groove portion is at its maximum distance from the surface of the tire tread or at its maximum depth. This is precisely the position where the first groove portion is adjacent to the second groove portion in the second radial direction R2, with the second groove portion located inside the first groove portion. The second groove portion is arranged closer to the center of the tire, and conversely, the second groove portion is farther from the tread surface than the first groove portion.

[0034] The width of the second groove portion varies by no more than 10% along the axial direction A of the pneumatic tire, preferably no more than 2%, and particularly preferably no more than 0.5%. However, in a highly advantageous embodiment, the width of the second groove portion can also be constant. Deviations in the width of the second groove portion exceeding this width are solely due to limitations in the production of the circumferential grooves. The resulting tolerance in the width of the second groove portion is typically less than 0.2 mm, preferably less than 0.15 mm, and particularly preferably less than 0.05 mm.

[0035] In this case, when the vehicle's pneumatic tire is new, the width of the second groove portion of the second section in the axial direction A is smaller than the width B of the second section on the tread surface in the axial direction A. Y,O The width of the second groove portion of the second section is 40%, preferably less than 30%, and particularly preferably less than 25%, compared to the original width of the second section of the circumferential groove on the tread surface of a new vehicle pneumatic tire. Therefore, the width of the second groove portion of the second section in the axial direction is significantly reduced compared to the original width of the second section of the circumferential groove on the tread surface.

[0036] The second groove portion of the second section extends in the radial direction R2 at least 50% of the height of the second groove portion of the first section in the radial direction R1.

[0037] The height H of the grooved portion of the cross-section of the circumferential groove in the radial direction R is defined as the maximum height of the cross-sectional area of ​​the grooved portion in the radial direction R, and is given by the maximum distance between two points on the edge of the cross-sectional area that are separated from each other only in the radial direction R. Their distance perpendicular to the radial direction is not considered here. This maximum distance can be precisely found in the radial direction R using a number of cross-sectional areas of the grooved portion present in a cross-section perpendicular to the circumferential direction of the circumferential groove of the pneumatic tire of the vehicle according to the invention. However, if the two edge points that are separated from each other by the maximum distance in the radial direction R lie on a straight line extending at a certain distance parallel to the radial direction R along the axial direction A, the maximum distance can also be found on that straight line. However, if the two points are not on a straight line parallel to the radial direction R, their distance in the axial direction A is not considered when determining the height of the grooved portion.

[0038] Therefore, the length of the second groove portion of the second cross section in the radial direction R2 of the cross section (the width of the second groove portion of the second cross section varies by up to 10% in the axial direction) and the height of the second groove portion of the second cross section in the radial direction R2 are associated with the height of the second groove portion of the first cross section, specifically in such a way that the length of the second groove portion of the second cross section corresponds to at least half the height of the second groove portion of the first cross section in the radial direction R1 of the first cross section.

[0039] Furthermore, the second groove portion of the second cross-section of the circumferential groove is at least 50% of its height in the radial direction R2 at a certain distance from the tread surface, and the second groove portion is located in the first cross-section at this distance. For the position in the circumferential groove, the distance from the tread surface corresponds to the depth of the circumferential groove at that position. Thus, the second groove portion of the second cross-section is located at the depth of the second groove portion of the first cross-section of the circumferential groove at at least 50% of its height. Therefore, the two groove portions (the second groove portion of the second cross-section and the second groove portion of the first cross-section) are located in the same depth region of the circumferential groove over a larger area of ​​the second groove portion of the second cross-section (i.e., over at least 50% of the range of the second groove portion of the second cross-section), but in different circumferential segments.

[0040] Compared to existing solutions where the cross-sections of circumferential grooves in vehicle treads alternate along the tire circumference, the improved geometry of the second cross-section of the circumferential grooves, perpendicular to the circumferential direction, improves the rolling resistance of the circumferential grooves in the region of the second cross-section without significantly reducing the behavior of the second cross-section in wet environments. This is achieved by narrowing the second groove portion of the second cross-section in the axial direction A to a width significantly reduced compared to the width of the second cross-section on the tread surface. The second groove portion of the second cross-section extends in the radial direction R2 to a significant length of at least 50% of the height of the second groove portion constituting the first cross-section. Here, the second groove portion is located only at a depth of at least 50% of the height of the circumferential grooves in the radial direction R2, the same depth as the second groove portion of the first cross-section, which serves as a reservoir for absorbing water from the road surface. Therefore, the first groove portion of the second cross section of the circumferential groove is largest at the depth of the circumferential groove, where at most 50% of the height of the second groove portion lies within the first cross section of the circumferential groove, or is largest only at the depth of the groove portion of the first cross section, the distance between the groove portion of the first cross section and the tread surface being less than the distance between the second groove portion of the first cross section (such as, in particular, the first groove portion of the first cross section) and the tread surface. Since the sides of the first groove portion now converge with increasing circumferential groove depth and terminate in a narrowing groove portion with decreasing width, the sides of the second groove portion are already compressed at a lower depth in the second cross section compared to circumferential grooves known in the prior art, and therefore the sides are in contact. This ultimately reduces tread deformation at lower depths, which further improves the rolling resistance of the vehicle pneumatic tire and increases the stiffness of the cross section. This effect is already applied in the vehicle pneumatic tire when it is new according to the invention. However, the first groove portion of the second section and its groove portion that can be arranged radially on the outer side provide sufficient capacity to receive road water and ensure good behavior of the circumferential grooves in wet environments, thereby ensuring vehicle safety through good braking behavior under wet conditions.

[0041] Because more than 50% of the height of the second groove portion of the second section is located at the depth of the second groove portion in the first section of the circumferential groove, if a transition section exists in the circumferential direction between these second groove portions of the two sections, road water can be exchanged between partial sections of the two sections and between the second groove portions of the two sections. In this way, water can enter the second groove portion of the first section through the narrowed second groove portion of the second section, and once the partial section of the circumferential groove is no longer in contact with the road, the water can escape from the circumferential groove again from the second groove portion of the first section. Further details will be explained below.

[0042] In a preferred embodiment, at least one second grooved portion of the second cross-section of the circumferential groove extends in the radial direction R2 at a height of at least 80% of the height of the second grooved portion of the first cross-section in the radial direction R1. The length of the second grooved portion of the second cross-section in the radial direction R2, and therefore the height of the second grooved portion of the second cross-section in the radial direction R2, is thus dimensionally determined based on the height of the second grooved portion, specifically in such a manner that the length of the second grooved portion of the second cross-section corresponds to at least 80% of the height of the second grooved portion of the first cross-section in the radial direction R1.

[0043] In a particularly preferred embodiment, the second grooved portion of the second cross-section extends in the radial direction R2 at least at the height of the second grooved portion of the first cross-section in the radial direction R1. Therefore, the length of the second grooved portion of the second cross-section along the radial direction R2 of the cross-section, and consequently the height of the second grooved portion of the second cross-section in the radial direction R2, are dimensionally determined based on the height of the second grooved portion, specifically in such a way that the length of the second grooved portion of the second cross-section corresponds at least to the height of the second grooved portion of the first cross-section along the radial direction R1 of the first cross-section.

[0044] Typically, at least one circumferential groove of the second cross section extends in the radial direction R2 at up to 125% of the height of the second groove portion of the first cross section in the radial direction R1, preferably at up to 115% of the height of the second groove portion of the first cross section in the radial direction R1, and particularly preferably at up to 110% of the height of the second groove portion of the first cross section in the radial direction R1. The height of the second groove portion of the second cross section in the radial direction R2 should not be too large, such that groove portions closer to the tread surface than the second groove portion (e.g., particularly the first groove portion with a given tread depth PT) have sufficient depth to adequately absorb road water, and thus contribute to the braking behavior of the vehicle's pneumatic tire in wet conditions.

[0045] In a preferred embodiment, at least 75% of the height of the second groove portion of the second cross section of the circumferential groove is at a distance from the tread surface, and the second groove portion is located in the first cross section at this distance. In a particularly preferred embodiment, the second groove portion of the second cross section is at a distance from the tread surface over its entire height in the radial direction R2, and the second groove portion is located in the first cross section at this distance. The greater the range of distances (i.e., the range of depths) from the surface where both the second groove portions of the first and second cross sections are present, the more road water can enter the second groove portion of the first cross section from the second cross section, and thus the behavior of the vehicle's pneumatic tire in wet environments can be improved.

[0046] Typically, in at least one circumferential groove of a vehicle pneumatic tire, the height of the first and second groove portions of the first section in the radial direction R1 is together greater than 70% of the circumferential groove tread depth PT, preferably greater than 80% of the circumferential groove tread depth PT, particularly preferably greater than 85% of the circumferential groove tread depth PT, and most preferably greater than 90% of the circumferential groove tread depth PT. Here, the first section also has at least one additional groove portion, which is further from the tread surface than the first and second groove portions, unless the height of the first and second groove portions of the first section already corresponds to the tread depth PT. The first groove portion then terminates at the tread surface. If at least one additional groove portion also belongs to the first section of the circumferential groove, it is preferred that the width of this additional groove portion in the axial direction A is greater than the width of the first groove portion, in order to improve the behavior of the vehicle pneumatic tire in wet environments by increasing its ability to absorb water from the road surface.

[0047] In a preferred embodiment, in the case of at least one circumferential groove, the bottom region of the circumferential groove directly adjoins the second groove portion of the second cross-section in the radial direction R2. The bottom region of the circumferential groove includes a groove bottom having the deepest point of the circumferential groove at the greatest distance from the tread surface. This distance corresponds to the tread depth PT. Starting from the deepest point of the circumferential groove, the width of the circumferential groove in the axial direction A steadily increases as the depth of the bottom region of the circumferential groove decreases (i.e., the distance from the tread surface decreases), until the bottom region reaches the width of the second groove portion of the second cross-section in the axial direction A. In one embodiment, the bottom region already has a certain width in the axial direction A at the deepest point of the circumferential groove. Thus, the groove bottom is formed by a straight line parallel to the axial direction A, which has the tread depth PT, and the bottom region of the second cross-section of the transverse groove is formed by a surface along the circumferential direction in the axial direction A. This surface preferably transitions via curvature into the sidewalls of the cross-sectional region of the second groove portion of the second cross-section.

[0048] Preferably, the bottom region of the second cross-section of the circumferential groove is symmetrical about the radial direction R2. In a particularly preferred embodiment, the bottom region of the second cross-section merges into the second groove portion of the second cross-section from the deepest point of the circumferential groove with a constant radius of curvature. This radius of curvature is determined by the width B of the second groove portion in the axial direction A. Y,2 What is produced is width B Y,2 Half of it. Therefore, the cross-section of the bottom region perpendicular to the circumferential direction is a semicircle, the diameter of which corresponds to the width B of the second groove portion in the axial direction A at the end of the second groove portion adjacent to the bottom region (i.e., the end furthest from the tread surface). Y,2 .

[0049] In these embodiments, the total height of the second groove portion of the second cross-section and the bottom region of the circumferential groove in the radial direction R2 is typically no more than 20%, preferably no more than 10%, and particularly preferably no more than 5%, between the edge point of the cross-sectional region of the second groove portion of the first cross-section perpendicular to the circumferential direction at the maximum distance from the radial direction R1 and the deepest point of that cross-sectional region in the radial direction R1. Thus, the height H2 of the second groove portion of the second cross-section in the radial direction R2 is... Y The sum of the heights of the bottom region of the second cross-section in the radial direction R2 (corresponding to the distance from the deepest point to the inner end of the second groove portion) approximately corresponds to the distance from the bottom of the groove of the widest extent of the second groove portion of the first cross-section, where the deepest point of the second groove portion of the first cross-section is located at the bottom of the groove of the first cross-section. Since the tread depth of the lateral grooves is the same across the entire tire circumference, the second groove portion and bottom region of the second circumferential groove are thus at the same depth as the region of the second groove portion below its maximum extent in the axial direction A. Therefore, these regions of the two cross-sections of the circumferential groove can communicate with each other through corresponding transition areas between the cross-sections, allowing road water entering the second groove portion of the second cross-section (particularly through tire rotation) to enter the second groove portion of the first cross-section under wet conditions. This significantly improves the water absorption capacity of the circumferential grooves.

[0050] In the case of at least one circumferential groove, in an embodiment where the bottom region of the circumferential groove directly abuts the second groove portion of the second cross-section in the radial direction R2, the average width B of the second groove portion of the second cross-section in the axial direction A is... Y,2 Typically, the width is 2 mm to 6 mm, preferably 2.5 mm to 4 mm, and particularly preferably 2.8 mm to 3.5 mm. With such a width, the sides of the second groove portion are compressed in the second cross-section, causing the sides of the second groove portion to contact each other. As a result, the deflection of the tread rubber material in the region of the second cross-section of the circumferential groove is significantly reduced. The rolling resistance of the vehicle pneumatic tire according to the invention is also correspondingly reduced by this dimensional setting.

[0051] Furthermore, in the embodiment where, in the case of at least one circumferential groove, the bottom region of the circumferential groove directly adjoins the second groove portion of the second cross-section in the radial direction R2, the maximum width B of the cross-sectional area of ​​the second groove portion of the first cross-section in the axial direction A is... V,2,max The average width B of the second groove portion of the second cross section in the axial direction A Y,2The ratio is typically between 1.5 and 4.5, preferably between 2.0 and 3.5, and particularly preferably between 2.3 and 2.8. This ratio of the width of the inner groove portions of the two cross sections is chosen in a manner that simultaneously optimizes the rolling resistance of the circumferential grooves and their behavior in humid environments.

[0052] In addition, in the embodiment where the bottom region of the circumferential groove directly adjoins the second groove portion of the second cross-section in the radial direction R2, and the second groove portion of the second cross-section has an average width B in the axial direction A. Y,2 The average width B of the first groove portion of the first cross section in the axial direction A V,1 The ratio is between 1.0 and 6.0, preferably between 2.0 and 4.5, and particularly preferably between 2.3 and 3. However, due to the width B of the second groove portion of the second cross-section... Y,2 Significantly larger, ensuring that road water can be absorbed by the second groove portion of the second section and then enter the second groove portion of the first section.

[0053] In another embodiment, in the case of at least one circumferential groove, the third groove portion is directly adjacent to the second groove portion of the second cross-section in the radial direction R2. The third groove portion includes the bottom region of the second cross-section and is teardrop-shaped. The maximum width B of the third groove portion in the axial direction A is... Y,3 The average width B of the second groove portion, which is larger than the second cross section, in the axial direction A. Y,2 The third groove portion of the second section is further from the tread surface than the second groove portion of the second section, where the second groove portion merges into the third groove portion. The width of the third groove portion increases axially until it reaches its maximum width B. Y,3 However, since the third groove portion is teardrop-shaped, it gradually narrows with increasing depth (i.e., increasing distance from the tread surface) until the deepest point of the circumferential groove at the bottom. The bottom of the groove can also be a straight line in the axial direction A, at the maximum distance from the tread surface, thus acting as the deepest point of the circumferential groove. The width of the third groove portion is greater than the width of the second groove portion, thus allowing for a larger volume to absorb road water entering the bottom of the second groove. Through the connection between the second groove portion of the first section and the transition region between the two sections present in the circumferential groove, water absorbed from the road, particularly due to the rotation of the vehicle's pneumatic tire, can then enter the second groove portion of the first section, which has an even larger volume for absorbing water from the road.

[0054] In a preferred embodiment, in the case of at least one circumferential groove, the edge of the cross-sectional region of the third groove portion of the second cross-section perpendicular to the circumferential direction is circular, and the diameter B of this circle is... Y,3 The average width B of the second groove portion, which is larger than the second cross section, in the axial direction A. Y,2 Typically, the diameter B of the circular edge of the cross-sectional region of the third groove portion of the second cross-section. Y,3 B is the average width of the second groove portion of the second cross section in the axial direction A. Y,2 The second groove portion of the second cross-section extends by a length H2 in the radial direction R2, which is 1.2 to 4 times larger, preferably 2 to 3 times larger, and particularly preferably 2.3 to 2.7 times larger. In this particularly preferred embodiment, the second groove portion of the second cross-section extends by a length H2 in the radial direction R2. Y The length is at least B times the diameter of the circular edge of the cross-sectional area of ​​the third groove portion. Y,3 The same size, preferably B, is greater than the diameter of the circular edge of the cross-sectional area of ​​the third groove portion. Y,3 Larger than 15%, particularly preferably larger than B than the diameter of the circular edge of the cross-sectional area of ​​the third groove portion. Y,3 25% larger. The length H2 of the second groove portion in the radial direction R2. Y This corresponds to the height of the second groove portion in the radial direction R2. Here, the second groove portion, due to its smaller width in the axial direction A, is considered a channel in the radial direction R2, which guides the road water into the circular droplet portion of the third groove portion and has a certain length H2. Y .

[0055] In embodiments where at least one circumferential groove includes the bottom region of the second cross-section and the third groove portion is droplet-shaped, directly adjoining the second groove portion of the second cross-section in the radial direction R2, typically, when the vehicle's pneumatic tire is new, the average width B of the second groove portion of the second cross-section along the axial direction A of the vehicle's pneumatic tire is... Y,2 The width B of the second section on the surface of the tread in the axial direction A is smaller than that of the second section. Y,O The value is 15%, preferably less than 12%, and particularly preferably less than 10%. Furthermore, in these embodiments, when the vehicle's pneumatic tire is new, the average width B of the second groove portion of the second section along the axial direction A of the vehicle's pneumatic tire is... Y,2 Typically, it is larger than the width B of the second section on the tread surface in the axial direction A. Y,O The width B of the second groove portion is selected for the second cross-section of the circumferential groove, preferably greater than 6%, and particularly preferably greater than 8%. Y,2 With width B Y,O This ratio, in particular, optimizes both the behavior of the circumferential grooves in wet environments and the rolling resistance.

[0056] In the case of at least one circumferential groove, the third groove portion directly and inwardly abuts the second groove portion of the second cross-section in the radial direction R2. In the embodiment where the third groove portion includes the bottom region of the second cross-section and is teardrop-shaped, the average width B of the second groove portion of the second cross-section in the axial direction A is... Y,2 Typically, it is 0.7 mm to 2.5 mm, preferably 1 mm to 1.7 mm, and particularly preferably 1.1 mm to 1.3 mm.

[0057] In embodiments where at least one circumferential groove includes the bottom region of the second cross-section and the third groove portion is droplet-shaped, directly adjoining the second groove portion of the second cross-section in the radial direction R2, the second groove portion of the second cross-section typically has a length H2 of 2 mm to 6 mm in the radial direction R2. Y The second groove extends upwards, preferably over a length of 2.7 mm to 4.5 mm, and particularly preferably over a length of 3.2 mm to 4 mm. This dimensional arrangement of the second groove portion contributes to a reduction in rolling resistance of the vehicle pneumatic tire according to the invention.

[0058] In one embodiment of the pneumatic tire of the present invention, the first groove portion of the second cross section of at least one circumferential groove widens outwardly at a constant rate. The side of the cross section region of the first groove portion perpendicular to the circumferential direction is thus formed by a straight line, and the cross section region of the first groove portion thus has an isosceles trapezoidal shape. In this case, the side of the cross section region of the first groove portion of the second cross section perpendicular to the circumferential direction of the pneumatic tire typically has an inclination of 20° to 80° relative to the radial direction R2, preferably an inclination of 30° to 60°, and particularly preferably an inclination of 40° to 50°.

[0059] In some embodiments, the second groove portion of the first cross-section of the circumferential groove may have a side surface that is partially straight and converges inward in the radial direction R1 (i.e., with increasing distance from the tread surface). Thus, typically, the ratio of the angle of inclination of the straight side surface of the first groove portion of the second cross-section perpendicular to the circumferential direction of the vehicle's pneumatic tire with respect to the radial direction R2 to the angle of inclination of the side surface of the second groove portion of the first cross-section converging inward in the radial direction R1 with respect to the radial direction R1 is between 1.5 and 10, preferably between 1.75 and 4, and particularly preferably between 2 and 2.5. Therefore, the inclination of the side surface of the first groove portion of the second cross-section is significantly greater than the inclination of the side surface of the second groove portion of the first cross-section. Due to the large slope of the side of the first groove portion of the second section, the rolling resistance of the vehicle's pneumatic tire tread in the region of the second section is reduced in a targeted manner compared to the prior art, because the rubber material of the tread is located closer to the surface of the tread, which gives the rubber material of the tread increased stiffness and less bending when the tire rotates in contact with the road.

[0060] In the pneumatic tire of the vehicle according to the invention, in the case of at least one circumferential groove, the ratio of the area of ​​the cross-sectional region perpendicular to the circumferential direction of the second groove portion of the first section to the area of ​​the cross-sectional region perpendicular to the circumferential direction of the second groove portion of the second section is between 1 and 3, preferably between 1.5 and 2.5, and particularly preferably between 2 and 2.3. Therefore, the area of ​​the second groove portion of the second section is preferably significantly smaller than the area of ​​the second groove portion of the first section because the sides of the second groove portion of the second section are designed to be compressed when in contact with the road. However, on the other hand, the size of the area of ​​the second groove portion of the second section is such that, under wet conditions, a certain amount of road water can still be absorbed into the second groove portion of the second section before the sides of the second groove portion of the second section are compressed. As a result, the absorbed water is forced into the second groove portion of the first section, which has a greater water absorption capacity.

[0061] In a preferred embodiment of a pneumatic tire, at least one segment of the circumferential groove having a first cross-section perpendicular to the circumferential direction has the same length in the circumferential direction, and similarly, a segment of the circumferential groove having a second cross-section perpendicular to the circumferential direction has the same length in the circumferential direction. Typically, the length of the segment of the circumferential groove having the first cross-section is between 25% and 75% of the total length of the circumferential groove, preferably between 30% and 70%, and particularly preferably between 40% and 60%.

[0062] Typically, the length of a portion of the circumferential groove of a pneumatic tire having a first cross-section is between 40% and 85% of the total length of the portion of the circumferential groove having a first or second cross-section, preferably between 60% and 80%, and particularly preferably between 70% and 78%. Particularly preferably, the total length of the portion of the circumferential groove having a first cross-section is three times the total length of the portion of the circumferential groove having a second cross-section. Correspondingly, in the case of circumferential grooves, the length of the first cross-section extending in the circumferential direction is three times the length of the second cross-section extending in the circumferential direction. If multiple circumferential grooves exist, the lengths of the first and second cross-sections extending in the circumferential direction can be different or the same. Depending on the geometry of the first and second cross-sections, it may be advantageous for the cross-sections to extend the same length or different lengths in the circumferential direction, resulting in the best possible behavior of the pneumatic tire in wet environments and reduced rolling resistance.

[0063] In a further preferred embodiment of a pneumatic tire, in the case of at least one circumferential groove, the cross-section of the circumferential groove in the transition region between a portion having a first cross-section and a portion having a second cross-section is V-shaped. This allows road water absorbed by the second groove portion of the cross-section to enter the second groove portion of the first cross-section, which has a high absorption capacity, particularly easily via the V-shaped transition region. Due to the length L3 of the transition region... Y Limited, where the narrowed second groove portion of the second cross-section is not fully formed, therefore the increased rolling resistance of the V-shaped cross-section is not particularly large in the circumferential direction. The length L3 of the transition region... Y Generally, it typically refers to the length L1 of the portion having the first cross-section on the tread surface. V It is 3% to 30%, preferably 10% to 25%, and particularly preferably 15% to 20%.

[0064] Typically, in the case of at least one circumferential groove, the total length of a portion of the first or second cross section of at least one circumferential groove on the circumference of the vehicle's pneumatic tire constitutes 50% to 90% of the total length of the circumferential groove in the circumferential direction, preferably 60% to 80% of the total length of the circumferential groove in the circumferential direction, and particularly preferably 65% ​​to 70% of the total length of the circumferential groove in the circumferential direction.

[0065] In a preferred embodiment, the pneumatic tire according to the invention has two adjacent circumferential grooves having alternating first and second cross-sections perpendicular to the circumferential direction on a portion of the circumference of the entire tire, as described above. In this case, all portions of the two circumferential grooves having the first cross-section, as well as portions of the circumferential grooves having two transition regions between the two cross-sections but not the first cross-section, and portions of the circumferential grooves having the second cross-section, have the same length. The arrangement of these portions on the two circumferential grooves is preferably such that if the first cross-section of the circumferential groove exists in one of the two circumferential grooves in the same portion of the other circumferential groove, then in the same portion of the other circumferential groove (i.e., in the portion of the circumferentially aligned section), there exists a portion having the second cross-section but not the first cross-section, and portions of the two transition regions between the two cross-sections. Therefore, in the case of two adjacent circumferential grooves, these portions are arranged at the same point on the circumference, but the circumferential grooves have two different cross-sections. In a circumferential position, one lateral groove thus has a first cross section, and another lateral groove has a second cross section or a transition region between the two cross sections (the first and second cross sections). In the subsequent segment of the circumferential direction, the cross sections are then interchanged between the two circumferential grooves. Therefore, as observed in the axial direction A, there is always a circumferential groove with a first cross section and a circumferential groove with a second cross section or a transition region. This arrangement is highly advantageous because the vehicle tire exhibits good and uniform behavior in wet conditions and improved uniform rolling resistance in both the circumferential and axial directions A.

[0066] If, in the case of at least one circumferential groove extending from a first cross-section and a second cross-section, the lengths of certain segments in the circumferential direction differ, a preferred embodiment has two adjacent circumferential grooves such that segments of the first cross-section and segments of the second cross-section are arranged on the two circumferential grooves in such a way that the center of one segment having the first cross-section in the circumferential direction is located on one of the two circumferential grooves, and the center of the segment having the second cross-section profile is located at the same position in the circumferential direction on the other of the two circumferential grooves. In this embodiment, the center of the segment having a cross-section on the circumference is located at the same position on two adjacent circumferential grooves. However, the two adjacent circumferential grooves each have different cross-sections at these positions, one circumferential groove having a first cross-section and the other having a second cross-section. This arrangement of cross-sections also means that the vehicle's pneumatic tire has good wet performance and reduced rolling resistance both circumferentially and axially.

[0067] In a preferred embodiment, the cross-sectional region of the second groove portion of the first cross-section of at least one circumferential groove includes the bottom region of the circumferential groove, which has an edge without corners. This reduces the risk of groove breakage in the first cross-section.

[0068] In another embodiment, the second cross-section of at least one circumferential groove is composed only of the first groove portion and the second groove portion. Thus, as described above, the bottom region of the circumferential groove is inwardly adjacent to the second groove portion.

[0069] In another embodiment, the second cross section of at least one circumferential groove is composed only of a first groove portion, a second groove portion, and a droplet-shaped third groove portion that surrounds the bottom region, and its advantageous construction has been described above.

[0070] In one embodiment of the pneumatic tire of the present invention, in the case of at least one circumferential groove, a fourth groove portion is externally adjacent to a first groove portion of the second cross-section on the surface of the tread of the pneumatic tire in the radial direction R2, and the width of the fourth groove portion in the axial direction A is greater than the maximum width B of the first groove portion of the second cross-section. Y,1 max The outward widening is no more than 40%, preferably no more than 10%, and particularly preferably no more than 0.5%. The fourth groove portion is primarily designed to absorb a larger amount of water from the road surface, and compared to the first groove portion, the fourth groove portion contributes almost nothing to reducing rolling resistance in the area of ​​the circumferential groove. Preferably, the fourth groove portion also terminates at the surface of the tread. Additionally, the fourth groove portion may preferably have a height H4 in the radial direction R2. Y It has a constant width in the axial direction A.

[0071] The height H4 of the fourth groove portion of the second section in the radial direction R2 Y Typically less than 40% of the pattern depth PT, preferably less than 10% of the pattern depth PT, and particularly preferably less than 5% of the pattern depth PT.

[0072] The height H4 of the fourth groove portion of the second section Y Typically less than 5 mm, preferably less than 3 mm, and particularly preferably less than 1 mm.

[0073] In one embodiment, the second cross-section is composed only of the first groove portion, the second groove portion, the third groove portion, and the fourth groove portion described above. The detailed construction of these groove portions of the second cross-section with at least one circumferential groove has been described above.

[0074] In one embodiment, in the case of at least one circumferential groove, a first section perpendicular to the circumferential direction, starting at the outer surface of the tread, is composed of three groove portions that are adjacent to each other and symmetrical about the radial direction R1 in the first radial direction R1 of the vehicle's pneumatic tire, wherein the third groove portion begins to widen outward on the outer surface of the tread, and the first groove portion adjacent to the third groove portion narrows relative to the third groove portion.

[0075] In this case, the third groove portion of the first cross-section preferably widens outwards at a constant rate. Thus, the ratio of the angle of inclination of the side of the cross-sectional area of ​​the first groove portion of the second cross-section perpendicular to the circumferential direction of the vehicle's pneumatic tire with respect to the radial direction R2 to the angle of inclination of the side of the cross-sectional area of ​​the third groove portion of the first cross-section perpendicular to the circumferential direction of the vehicle's pneumatic tire with respect to the radial direction R1 is typically between 0.9 and 1.4, preferably between 1 and 1.3, and particularly preferably between 1.1 and 1.2.

[0076] In general, it should be mentioned again that, due to the geometry of the second cross-section of at least one lateral groove of the pneumatic tire according to the invention, when the cross-section contacts the road, the sides of the second groove portion of the second cross-section contact each other faster than in the case of the corresponding (second) cross-section known from the prior art. This reduces the deformation of the rubber material in the region of the lateral groove and increases the stiffness of the tread in that region. As a result, the energy input to the rubber material of the pneumatic tire due to the rolling motion of the tire is reduced, and therefore the rolling resistance of the pneumatic tire is also reduced. In addition, the geometry of the circumferential groove of the pneumatic tire according to the invention is designed so that road water can be transported between the second groove portions of the two cross-sections. As a result, a drainage system for water is present in the circumferential groove, which improves the behavior of the pneumatic tire according to the invention in wet environments, especially its water absorption capacity. In particular, the pneumatic tire according to the invention can be used in trucks, where the reduced rolling resistance reduces fuel consumption and still provides a high level of vehicle safety because of good behavior in wet conditions, especially good braking behavior in wet conditions, which is aided by the improved ability to absorb water from the road. These performance characteristics can be specifically optimized as needed using the specified implementation examples. Attached Figure Description

[0077] The invention will be described in more detail through several exemplary embodiments, wherein: Figure 1 The first cross-section of a circumferential groove with three grooved sections is shown. Figure 2 The second V-shaped cross-section of the circumferential groove according to the prior art is shown. Figure 3The image shows tread details of a pneumatic vehicle tire with two circumferential grooves according to the prior art. Figure 4 The first cross-section of a circumferential groove with two grooved portions is shown. Figure 5 A second cross-section of the circumferential grooves of a first embodiment of a vehicle pneumatic tire according to the present invention is shown. Figure 6 The illustration shows tread details of a first embodiment of a pneumatic vehicle tire with circumferential grooves according to the present invention. Figure 7 A second cross-section of the circumferential grooves of a second embodiment of a vehicle pneumatic tire according to the present invention is shown. Figure 8 Details of the tread of a second embodiment of a pneumatic vehicle tire with circumferential grooves according to the present invention are shown. Figure 9 A second cross-section of the circumferential grooves of a third embodiment of a vehicle pneumatic tire according to the present invention is shown. Figure 10 Details of the tread of a third embodiment of a pneumatic vehicle tire with circumferential grooves according to the present invention are shown. Figure 11 A second cross-section of the circumferential grooves of a fourth embodiment of a vehicle pneumatic tire according to the present invention is shown. Figure 12 Details of the tread of a fourth embodiment of a pneumatic vehicle tire with circumferential grooves according to the present invention are shown. Figure 13 The diagram shows a second cross-section of the circumferential grooves of a fifth embodiment of a pneumatic tire for vehicles according to the present invention. Figure 14 A second cross-section of the circumferential grooves of a sixth embodiment of a vehicle pneumatic tire according to the present invention is shown. Figure 15 The illustration shows tread details of a first embodiment of a pneumatic vehicle tire with circumferential grooves according to the present invention, showing the entire portion of the circumferential grooves having a first cross-section. Figure 16 The illustration shows tread details of a first embodiment of a pneumatic vehicle tire with circumferential grooves according to the present invention, showing the entire portion of the circumferential grooves having a second cross-section. Figure 17 The diagram shows a cross-section of the circumferential grooves of a vehicle pneumatic tire according to a first embodiment of the invention, perpendicular to the axial direction A. Figure 18 The diagram shows a cross-section of the circumferential grooves of a first embodiment of a pneumatic tire according to the invention, perpendicular to the axial direction A, when in contact with a wet road surface. Figure 19 The illustration shows tread details of a first embodiment of a pneumatic vehicle tire with two circumferential grooves according to the present invention. Figure 20 The illustration shows tread details across the entire tread width under new conditions, according to a first embodiment of a pneumatic tire for vehicles based on the invention. Figure 21 The illustration shows tread details of a first embodiment of a pneumatic tire for vehicles according to the present invention, with a remaining tread depth of 4 mm over the entire tread width. Detailed Implementation

[0078] First, embodiments of the prior art will be described again before proceeding to the description of various embodiments of the present invention. It is important here that both cases relate to a vehicle pneumatic tire having one or more circumferential grooves, these grooves having a first cross-section and a second cross-section at different portions of the circumference.

[0079] first, Figure 1 A first cross-section of the circumferential groove is shown, which exists in the prior art, or may exist in both the prior art and embodiments according to the invention. This cross-section has been briefly described above. Figure 1 The diagram shows circumferential grooves 1 arranged in the tread 2 of a vehicle pneumatic tire. The cross-section of the circumferential grooves shown has three groove portions. The first groove portion 3 has a constant width B of 1.2 mm. V,1 .

[0080] The first groove portion is symmetrical about the radial direction R1. The second groove portion 4 is adjacent to it inwardly in the radial direction R1. That is, the groove portion 4 is further from the surface of the tread 2 than the first groove portion 3. In the groove portion 4, the cross section perpendicular to the circumferential direction is also symmetrical about the radial direction R1 of the first cross section of the circumferential groove 1. Here, the second groove portion 4 has a maximum width B of 7.5 mm. V,2,max .

[0081] Furthermore, the second groove portion 4 includes the bottom region 6 of the first cross-section of the circumferential groove 1. The bottom region 6 has a radius of curvature R1 of 1.5 mm. V These straight edges, which merge into the straight edges of the second groove section 4, converge in the radial direction R1 as the depth of the circumferential groove increases. Typically, the radius of curvature R1... V The value is between 0.8 mm and 2.5 mm, preferably between 1 mm and 2 mm, and particularly preferably between 1.3 mm and 1.7 mm. Starting from the first groove portion 3, as the depth of the circumferential groove increases, the second groove portion 4 is at an angle A1 of 120°. V Open. In the example shown, the second groove section 4 then opens until it reaches its maximum width B.V,2,max The opening angle A1 of the second groove section 4 V Typically 90° to 180°, preferably 110° to 160°, and particularly preferably 115° to 140°. The height H2 of the second groove portion 4. V It is 6.5 mm. Typically, the height H2 of the second groove portion 4 is... V The circumferential groove depth PT is 40% to 70%, preferably 45% to 65%, and particularly preferably 50% to 60% of the circumferential groove depth PT. Typically, the height H2 of the second groove portion 4... V The diameter is 2.4 mm to 12.5 mm, preferably 3.6 mm to 10.5 mm, and particularly preferably 5 mm to 8.5 mm.

[0082] In an embodiment of the present invention, the height H1 of the first groove portion 3 of the first cross section is... V Typically, the pattern depth PT is between 20% and 60%, preferably between 25% and 55% of the pattern depth PT, and particularly preferably between 35% and 50% of the pattern depth PT. Typically, the height H1 of the first groove portion 3... V The thickness is from 1.2 mm to 10.8 mm, preferably from 2 mm to 8.8 mm, and particularly preferably from 3.5 mm to 7 mm.

[0083] exist Figure 1 In the exemplary embodiment shown, the third groove portion 5 is outwardly adjacent to the first groove portion 3 of the first cross-section in the radial direction R1. Therefore, the groove portion 5 extends from the first groove portion 3 in the radial direction R1 to the tread surface. The width of the third groove portion 5 increases with the distance from the surface of the tread 2, from the width B of the first cross-section on the surface of the tread 2. V,O Stably reduced to the width B of the first groove portion 3 V,1 Correspondingly, the side surface of the cross-sectional area of ​​the third groove portion 5 forms a straight line perpendicular to the circumferential direction. In an exemplary embodiment, when the vehicle's pneumatic tire is new, the width B of the first cross-section of the circumferential groove in the axial direction A on the surface of the tread 2 is... V,O The width B of the first cross-section on the surface of the first tread 2 is 4 mm. In other embodiments of the pneumatic tire of the present invention, the first cross-section of the circumferential groove is composed of three groove portions, and when the pneumatic tire is new, the width B of the first cross-section on the surface of the first tread 2 is... V,O Typically, it is 1.5 mm to 7 mm, preferably 3 mm to 6 mm, and particularly preferably 3.5 mm to 5 mm.

[0084] Figure 2 The second cross-section of the circumferential groove is shown, wherein, has Figure 1 The first section shown has a portion of the cross section and has Figure 2 The second section shown exists in an alternating manner along the entire circumference of the tire.

[0085] As mentioned above, it has Figure 1 and Figure 2 Examples of cross-sections are known in the prior art. Figure 2 The circumferential groove shown has a cross-section that is symmetrical about the radial direction R2 and has a V-shaped section 13. As the depth increases, the two sides of the section perpendicular to the circumferential direction converge toward the radial direction R2. Furthermore, the section has a bottom region 14 formed by a surface along the axial direction A. As already described, this cross-section is well-suited for absorbing road water under wet conditions and thus improves braking behavior in wet environments. However, the rigidity of the rubber material around the section is therefore compromised, and consequently, considerable bending work is performed in the tire material as the tire rolls on the road, which consumes energy. Correspondingly, the rolling resistance of the tire increases due to this shape of the circumferential groove.

[0086] Figure 3 Details of the tread 2 of a pneumatic tire known in the prior art are shown. Two circumferential grooves 1 are shown here, extending in a parallel, circumferential manner and simultaneously having… Figure 1 The first section shown and Figure 2 The second cross-section is shown. Here, the two circumferential groove sections 21 have Figure 1 The first cross-section shown, while a portion of section 22 in the two circumferential grooves has Figure 2 The second V-shaped cross-section is shown. Between the two cross-sections, there are transition regions 23 in the circumferential direction, where the two cross-sections merge with each other. For optimal utilization... Figure 1 The advantageous rolling resistance of the first cross-section and the advantageous behavior of the second V-shaped cross-section in a wet environment are illustrated by the fact that a portion of the first cross-section 21 and a portion of the second V-shaped cross-section 22 are arranged in the circumferential direction at the same location in two parallel circumferential grooves. The alternating arrangement of the two cross-sections in the circumferential direction of the grooves, and in the case of grooves parallel in the axial direction A, implies the uniform application of advantageous rolling resistance and advantageous behavior in a wet environment on the tread surface. Nevertheless, further improvements are needed in this prior art regarding rolling resistance to further reduce fuel consumption and thus reduce CO2 emissions from vehicles equipped with pneumatic tires.

[0087] Figure 4 Another embodiment of how the first cross-section of the circumferential groove 1 can be designed is shown. In this case, the cross-section has only two grooved portions. Figure 1Compared to the cross-section shown, the third groove portion 5 has been omitted, and the height of the first groove portion 3 has therefore been increased in the radial direction R1. Although Figure 1 All other proportions of the cross-section shown also exist. Figure 4 In the cross-section, however, the width B of the circumferential grooves on the surface of the tread 2 is... V,O It is now significantly reduced. The width is now the width of the first groove portion. Accordingly, in Figure 4 In the cross-section shown, the width B at the surface of tread 2 V,O The current value is 1.2 mm. Overall, in embodiments where only the first groove portion and the second groove portion are present in the first cross-section, the width B of the first groove portion 3... V,1 It is also the width B of the cross section at the surface of tread 2. V,O . Figure 1 and Figure 4 An embodiment of the first cross-section has now been shown by way of example, which can also exist in the circumferential groove 1 of a vehicle pneumatic tire according to the invention. In contrast, an improved cross-sectional geometry is used for the second cross-section of the circumferential groove 1 of a vehicle pneumatic tire according to the invention.

[0088] Figure 5 A second cross-section of the circumferential groove 1, belonging to a first embodiment of a pneumatic tire for vehicles according to the present invention, is shown. The cross-section shown has a first groove portion 33 that widens steadily outward. A second groove portion 34 is adjacent inward in the radial direction R2.

[0089] The grooved portion has a constant width B in the axial direction A. Y,2 The constant width B of the second groove portion 34 Y,2 The first groove portion has a width of 3 mm. The height of the second groove portion in the radial direction R2 is 4.55 mm. Since the width of the second groove portion 33 continuously widens from the second groove portion toward the surface of the tread 2, the cross-section of the first groove portion has a side surface given by a straight line. The width of the first groove portion 33 in the axial direction A is equal to the width of the second groove portion 34 by B. Y,2 Widening until the lateral grooves reach a width B on the surface of tread 2. Y, o. With the vehicle's pneumatic tire in its new condition, the width is 11 mm. The height H of the first groove portion 33 in the radial direction R2. 1,Y It is 5.95 mm. Figure 5The second cross-section shown is designed to be symmetrical about the radial direction R2. Correspondingly, the two groove portions 33 and 34 are also symmetrical about the radial direction R2. The bottom region 37 of the circumferential groove is adjacent inwardly to the second groove portion 34 of the cross-section shown in the radial direction R2. The bottom region 37 has the lowest point 38 of the cross-section of the circumferential groove. The bottom region 37 also has a constant radius of curvature R1. Y Accordingly, the bottom region 37 is formed by a semicircle, the diameter of which corresponds to the width B of the second groove portion. Y,2 Correspondingly, the radius of curvature R1 of the bottom region Y It is 1.5 mm.

[0090] Figure 6 Details of the tread of a first embodiment of a pneumatic tire for vehicles according to the present invention are shown. The details of the tread 2 show circumferential grooves 1, which have grooves in the circumferential direction with... Figure 1 The first section shown is a portion 21 and has Figure 5 The second cross-section shown is a portion 24. Additionally, a transition region 23 between portions 21 and 24 of the two cross-sections (the first and second cross-sections) is shown in the circumferential direction. The first grooved portion 33, the second grooved portion 34, and the bottom region 37 of the second cross-section are clearly visible in the front cross-section region.

[0091] Figure 7 A second cross-section of the circumferential groove of a second embodiment of a pneumatic tire for vehicles according to the present invention is shown. Again, the first cross-section of the circumferential groove has, for example... Figure 1 and Figure 4 The cross-section shown. Also in this embodiment, the second cross-section has a first grooved portion 33, a second grooved portion 34, and a bottom region 37. (And...) Figure 5 Compared to the cross-section of the first embodiment shown, the geometry and dimensions of the second groove region 34 and the bottom region 37 remain unchanged. The fourth groove portion 36 abuts the first groove portion 33 on the outer side of the surface facing the tread 2. Although the width of the first groove portion 33 steadily increases with decreasing distance from the surface of the tread 2, it reaches a width B. Y,O However, the fourth groove portion 36 has a constant width B in the axial direction A. Y,O The height H of the first groove portion 33 in the radial direction R2 1,Y The height H of the fourth groove portion 33 is 3.9 cm. 4Y It is 2.05 cm. The two straight lines on the side of the cross-sectional area of ​​the first groove portion 33 are inclined relative to each other, such that the two straight lines form an angle A1 of 80°. YIn other embodiments, the tilt angle between the two sides relative to each other is typically 30° to 180°, preferably 50° to 150°, and particularly preferably 75° to 120°.

[0092] Figure 8 A detail of the tread 2 according to a second embodiment of one of the pneumatic tires for vehicles according to the present invention is shown. In this detail of the tread 2, circumferential grooves 1 are present. A tire with... Figure 1 A portion 21 of the circumferential groove 1 in the first cross-section is shown. Also shown is a section 21 with... Figure 7 The second cross-section shown is a portion 24 of the circumferential groove 1. The components of the second cross-section of the circumferential groove 1 are particularly visible at the front end of the tread detail. A first groove portion 33, which widens towards the tread surface, a second groove portion 34 with a constant width adjacent to the tire interior, and a region 37 of the second cross-section adjacent to this second groove portion are seen. Furthermore, a fourth groove portion 36, starting directly on the surface of the tread 2, has a constant width in the axial direction A. In the circumferential direction, a transition region 23 remains between the first and second cross-sections of the circumferential groove 1.

[0093] Figure 9 A second cross-section of the circumferential groove 1, belonging to a third embodiment of a pneumatic tire for vehicles according to the invention, is shown. Similarly, the circumferential groove 1 has another first cross-section, which may be, for example... Figure 1 or Figure 4 The cross section shown. Figure 9 The second cross-section perpendicular to the circumferential direction is composed of a first groove portion 33, an inwardly adjacent second groove portion 34, a bottom region 37 of the second cross-section adjacent to the inwardly adjacent second groove portion 34, and a fourth groove portion 36 that extends outwardly toward the tread surface and adjacent to the first groove portion 33 in the radial direction R2. The geometry and dimensions of the second groove portion 34 and the bottom region 37 correspond to... Figure 5 The geometry and dimensions of the second groove portion and the bottom region of the first embodiment are shown. In the case of the first groove portion 33, the width in the axial direction A steadily increases as the distance from the tread surface decreases. Accordingly, the sides of this groove portion are initially formed by straight lines. The straight lines on these two sides form an angle A1 of 145°. Y Additionally, the first groove portion 33 has curvature in the region with the smallest distance from the tire surface. The radius of curvature of said curvature is R3. Y The value is 1.5 mm. In other embodiments with a second cross-section having the same geometry, the angle A1 formed by the two straight lines on the side of the first groove portion 33 is 1.5 mm. YTypically between 110° and 180°, preferably between 125° and 165°, and particularly preferably between 135° and 155°. The radius of curvature R3 of the first groove portion 33. Y Typically between 0.8 mm and 6 mm, preferably between 1.2 mm and 4 mm, and particularly preferably between 1.35 mm and 3 mm. Similarly, in the case of the fourth groove portion 36, which extends outwardly adjacent to the first groove portion 33 and terminates at the surface of the tread 2, the width steadily increases in the axial direction A until the width B on the surface of the tread 2. Y,0 Here, the side surface of the cross-sectional area of ​​the fourth groove portion 36 perpendicular to the circumferential direction is also formed by straight lines. In the exemplary embodiment shown, the angle A2 between the straight lines on the side surface is... Y It is 42°. In having Figure 9 In other embodiments of the geometry, the angle A2 of the straight line on the side of the fourth groove portion 36 Y Typically, the angle can be between 0° and 90°, preferably between 10° and 60°, and particularly preferably between 30° and 50°. The height H1 of the groove portion 33 Y The height H2 of the second groove portion 34 in the radial direction R2 is 2.25 mm. Y It is 5.17 mm. The height H4 of the fourth groove portion 36 is... Y It is 3.08 mm. In other embodiments, with Figure 9 The second cross section, which has the same geometry as the first groove portion 33, has a height H1. Y The height H4 of the fourth groove section 36 Y and the angle A1 between the sides of the grooved portion Y and A2 Y The selection is adapted accordingly. In other embodiments with a second cross-section having the same geometry, the total height of the first groove portion 33 and the fourth groove portion 36 in the radial direction R2 is typically 4 mm to 6.5 mm, preferably 4.5 mm to 6 mm, and particularly preferably 5 mm to 5.5 mm.

[0094] Figure 10 Details of the tread 2 of a third embodiment of a pneumatic tire for vehicles according to the present invention are shown. The circumferential grooves 1 are also shown again in this detail. Here it can be seen that the circumferential grooves 1 have, in the circumferential direction, a... Figure 1 The first cross-section shown is a portion 21. The circumferential groove 1 with [missing information] in the circumferential direction is also shown. Figure 9A portion 24 of the second cross-section is shown. The first groove portion 33, the second groove portion 34, the groove bottom 37, and the fourth groove portion 36 of the cross-section can be seen at the lower end of the cross-section. The transition region 23 where the first cross-section of the circumferential groove 1 merges into the second cross-section of the circumferential groove is also shown.

[0095] Figure 11 A circumferential groove 1 according to a fourth embodiment of a pneumatic tire for vehicles according to the present invention is shown. A cross-section of this circumferential groove perpendicular to the circumferential direction of the tire is then shown. This cross-section is a second cross-section of the circumferential groove 1. Furthermore, the circumferential groove has, for example, as shown... Figure 1 and Figure 4 The first cross-section is shown as an example. A first grooved portion 33 that widens outwards is shown. Then a second grooved portion 34 is adjacent to it in the radial direction R2. This grooved portion has a width B of 1.2 mm. Y,2 In the case of the first groove portion 33, the width in the axial direction is greater than the width B of the groove portion 34. Y,2 Continuously widening until the width B on the surface of tread 2. Y,O When the vehicle's pneumatic tires are new, the width of the tread surface is 11 mm. The height H1 of the first groove portion 33. Y It is 5.57 mm. The height H2 of the second groove portion 34 Y The diameter is 3.43 mm. The second groove portion 34 is adjacent to the third groove portion 35 in the radial direction R2. The third groove portion includes the bottom region 37 of the second cross section and is teardrop-shaped. The cross section of the third groove portion 35 perpendicular to the circumferential direction is circular and has a diameter B of 3 mm. Y,3 The lowest point 38 of the second section is located in the bottom region 37 surrounded by the third groove portion 35.

[0096] Figure 12 Details of the tread 2 of a fourth embodiment of a pneumatic tire for vehicles according to the present invention are shown. In this detail, circumferential grooves 1 are present. The circumferential grooves 1 are shown having... Figure 1 The first cross-section shown is a portion 21. A circumferential groove with... Figure 11 The second section 24 is shown. In the lower section of the tread detail, the first groove portion of the second section 33, the second groove portion 34 of the second section, and the third groove portion 35 of the second section can also be seen. A transition region 23 between the two sections 21 and 24 is also shown, in which the first section of the circumferential groove 1 merges into the second section of the circumferential groove 1.

[0097] Figure 13A second cross-section of the circumferential groove 1, belonging to a fifth embodiment of a pneumatic tire for vehicles according to the present invention, is shown. The first cross-section of this circumferential groove 1 may then be... Figure 1 The cross section shown or Figure 4 The cross-section shown. Here, the second cross-section also has four grooved portions. The first grooved portion 33 and the fourth grooved portion 36 correspond to... Figure 9 The third embodiment shown includes the first groove portion 33 and the fourth groove portion 36. This relates to geometry, size, and angle. The second groove portion 34 and the third groove portion 35 of the fifth embodiment correspond to... Figure 11 The second groove portion 34 and the third groove portion 35 of the fourth embodiment are shown. Correspondingly, the geometry and dimensions of the two embodiments are the same.

[0098] Figure 14 A second cross-section of the circumferential groove 1 according to a sixth embodiment of a pneumatic tire for vehicles according to the present invention is shown. In this sixth embodiment, the cross-section also has a first groove portion 33, a second groove portion 34 adjacent inwardly in the radial direction R2, a third groove portion 35 adjacent inwardly in the radial direction R2 to the second groove portion, and a fourth groove portion 36 adjacent outwardly in the radial direction to the first groove portion 33. The geometry and width of the second groove portion 34 and the third groove portion 35 in the sixth embodiment correspond to... Figure 11 The geometry and width of the second and third groove portions in the fourth embodiment shown. The height H2 of the second groove portion 34. Y The width is 4.1 mm. As the distance from the surface of the tread 2 decreases, the width of the first groove portion 33 in the axial direction A changes from B... Y,1 min (It is 5.4 mm) widened to width B Y,1 max (It is 8 mm). Due to the minimum width B of this groove portion Y,1min Width B greater than the second groove portion Y,2 Therefore, the first groove portion 33 has a width of B in the axial direction A. Y.1min The area is described. Starting from this area, the first groove portion 33 widens due to the curvature of its side surface. The fourth groove portion 36 is adjacent to it outwards in the radial direction R2. In this groove portion, the width in the axial direction A increases from the width B... Y,1max Stably widening to width B at the surface of tread 2. Y,0 (It is 11 mm).

[0099] Figure 15 Details of the tread 2 of a first embodiment of a pneumatic tire for vehicles according to the present invention are shown. Circumferential grooves 1 are shown, and the circumferential grooves 1 having the following characteristics are illustrated in the circumferential direction. Figure 1 The first cross-section shown represents the entire section 21. The length L1 of this section 21 in the circumferential direction is...V The length of the portion 21 having the first cross-section in the circumferential groove of the vehicle pneumatic tire according to the invention is generally 25 mm to 120 mm, preferably 40 mm to 100 mm, and particularly preferably 60 mm to 90 mm.

[0100] Figure 16 Further details of the tread 2 of a first embodiment of a pneumatic tire for vehicles according to the present invention are shown, in which circumferential grooves 1 are located. This detail shows the circumferential grooves 1 having… Figure 5 The entire section 24 of the second cross-section is shown. Furthermore, the circumferential groove 1 can also be seen. Figure 1 A portion of section 21 of the first cross-section is shown. Additionally, the transition region 23 between the first and second cross-sections of the circumferential groove 1 is shown. Further details are shown at the lower end. Figure 1 The first cross-section of the circumferential grooves is shown, wherein, in particular, the first groove portion 3, the second groove portion 4, and the third groove portion 5 are visible. Furthermore, a distance L is shown. 1Y This distance indicates the circumferential distance between the two partial segments 21 having the first cross-section. Now back to... Figure 15 The diagram shows a complete partial section 21 of the circumferential groove 1 with a first cross-section. Additionally, a circumferential groove with... Figure 5 A portion of section 24 of the second cross-section is shown. At the lower end of the detail, the second cross-section can be clearly seen again, particularly the first groove portion 33, the second groove portion 34, and the bottom region 37 of the second cross-section of the circumferential groove 1. Furthermore, Figure 15 The diagram shows the intersecting lines A, A', B, B' and C, C' in the axial direction A. Figure 1 The cross-section of the circumferential groove 1 along lines A and A' is shown, that is, the cross-section passing through the first cross-section of the circumferential groove 1. Figure 2 A cross-section along lines B and B' is shown. This cross-section is located in the transition region 23 between the two cross-sections of the circumferential groove. From Figure 2 It can be seen that the cross-section in the transition region is V-shaped. Then, Figure 5 A cross-section along lines C and C' is shown, which is the cross-section passing through the second cross-section of the circumferential groove 1. Additionally... Figure 16 The diagram shows cross-sectional lines D and D'. These cross-sectional lines extend along the circumferential grooves, and their cross-sectional areas are perpendicular to the axial direction A. Figure 17 The cross-sections of lines D and D' along the circumferential grooves are shown. The tread 2 of a pneumatic tire is shown, with the tread surface at the top. The distance L1 is shown here. YThis distance describes the distance between two partial segments having a first cross-section. In the exemplary embodiment shown, this distance corresponds to the length L1 of the partial segment 21 in the circumferential direction. V Furthermore, the length L2 is shown. Y This length corresponds to the circumferential length of the portion 24 having the second cross-section, including the circumferential length of two adjacent transition regions 23, where the narrowed second groove portion of the second cross-section still exists entirely within the transition region. This length is 42 mm. In the cross-sectional groove of the vehicle pneumatic tire according to the invention, the length L2... Y Typically, it is 8 mm to 110 mm, preferably 25 mm to 80 mm, and particularly preferably 35 mm to 50 mm. Furthermore, a length L3 is also shown. Y This length describes the circumferential length of the transition region 23 between the first and second cross-sections, in which the narrowed second groove portion of the second cross-section is absent or incomplete. In the illustrated exemplary embodiment, this length is 19 mm. The length L3 of the transition region 23... Y Typically, it is 5 mm to 35 mm, preferably 10 mm to 30 mm, and particularly preferably 15 mm to 25 mm. Figure 17 A portion 24 of the circumferential groove 1 with a second cross-section is shown. A portion of each of the two portions 21 of the circumferential groove 1 with a first cross-section is also shown. One side of the first groove portion 33 of the second cross-section of the circumferential groove 1 can also be seen. One side of the second groove portion 34 of the second cross-section is also shown. One side of the second groove portion 4 of the first cross-section is also seen. As can be seen from this illustration, the second groove portion 4 of the first cross-section and the second groove portion 34 of the second cross-section are at the same depth in the tread 2. Figure 18 The same details of the vehicle pneumatic tire according to the invention are now shown when the vehicle pneumatic tire comes into contact with the road 40 under wet conditions. It should be noted that, in Figure 17 and Figure 18In the diagram, the top and bottom have been inverted. This illustrates how water from the road surface 42 is absorbed by the circumferential groove 1. This is specifically demonstrated by the arrows shown. It can be seen that road water permeates into the second section 24 of the circumferential groove 1, which has a second cross-section. The road water can then permeate through two transition regions 23 into the second groove portion 4 of the first cross-section of the circumferential groove portion 21. Specifically, as indicated by the arrows, a drainage effect occurs here, resulting in road water initially being absorbed by the second cross-section in the portion 24 and entering the first cross-section via the transition regions 23. As a result, the vehicle pneumatic tire according to the invention has a high water absorption capacity for road water. However, due to the improved structure of the second cross-section in the portion 24, the rolling resistance in these portions is significantly reduced compared to the prior art. Therefore, the vehicle pneumatic tire according to the invention exhibits very good behavior and low rolling resistance in wet environments. In the case of the vehicle pneumatic tire according to the invention, rolling resistance is thus optimized without any significant loss of safety. This optimization of rolling resistance, i.e., minimization of rolling resistance, can reduce the fuel consumption of a vehicle equipped with pneumatic tires according to the invention, and correspondingly reduce the vehicle's CO2 emissions.

[0101] Figure 19 , Figure 20 and Figure 21 Further details of the tread 2 of a first embodiment of a pneumatic tire for vehicles according to the present invention are shown. Two circumferential grooves 1 are shown here, extending parallel to each other and having [specific features] in a portion 21 in the circumferential direction. Figure 1 The first cross section shown, and having in the circumferential direction a portion of segment 24 Figure 5 The second cross section is shown. Figure 19 The diagram also shows a transition region 23 between two circumferential groove segments 21 and 24. It illustrates that, in the case of two circumferential grooves 1, the two cross-sectional segments 21 and 24 are each arranged at the same circumferential position. Segment 21 with the first cross-section is located in the circumferential groove, and segment 24 with the second cross-section is located in the second circumferential groove, and vice versa. This also... Figure 20 and Figure 21 As shown in the figures, these two figures illustrate even greater details of the tread 2 in the circumferential direction and across the entire width of the tread 2. This distribution of the portions 21 and 24 on the parallel circumferential grooves 1 uniformly distributes the characteristics of the tread 2 of the vehicle pneumatic tire according to the invention across the circumference and width of the vehicle pneumatic tire. In all locations of the tread 2, it behaves well in wet conditions and exhibits low rolling resistance.

[0102] exist Figure 20 and Figure 21The image shows the tread 2 of a vehicle pneumatic tire across its entire width. The tread 2 has a total of four circumferential grooves. In addition to the two circumferential grooves 1 with first and second cross-sections, two outer grooves 51 also exist in the tread pattern of the vehicle pneumatic tire. These two outer grooves 51 have a V-shaped cross-section. Although... Figure 20 The tread pattern on tread 2 is shown to be new, but Figure 21 The diagram shows the tread condition when the circumferential groove depth is reduced to 4 mm. Comparing the two figures, it is clear that in the case of the two circumferential grooves 1, certain sections have changed; sections of circumferential groove 1 with an open section on the tread surface or a very narrow section in the axial direction A have changed. It can be seen that due to the structure of the first section, even in each groove portion, such as… Figure 21 The premature wear shown still indicates the presence of sections of circumferential grooves 1 suitable for absorbing water from the road surface. Within these sections, the second groove portion 4 of the first cross-section lies on the surface of the tread 2. This demonstrates that the vehicle pneumatic tire according to the invention exhibits good wet behavior and low rolling resistance throughout its service life.

[0103] The nominal width of the vehicle pneumatic tire according to the invention is typically 280 mm to 460 mm, preferably 290 mm to 400 mm, and particularly preferably 300 mm to 330 mm. In the embodiment shown in the figures, the nominal width of the vehicle pneumatic tire is 315 mm. The nominal width of the vehicle pneumatic tire is defined according to ISO standard 5775.

[0104] For a pneumatic tire for a vehicle according to the invention, the nominal section ratio (i.e., the ratio of tire height to nominal width (in %)) is typically 40% to 95%, preferably 45% to 80%, and particularly preferably 50% to 70%. In the embodiment shown in the figures, the ratio of tire height to nominal width is 70%.

[0105] The pneumatic tires of the vehicle according to the invention typically have 2 to 6 grooves, preferably 3 to 5 grooves, and particularly preferably 4 circumferential grooves.

[0106] The pneumatic tires of the present invention are used on wheels with a rim diameter preferably 19.5 inches and particularly preferably 22.5 inches.

[0107] The pneumatic tires for vehicles according to the invention are preferably used on buses and trucks. They are used on light trucks, preferably on medium trucks (especially trucks with a gross vehicle weight greater than 7.2 tons), and very particularly preferably on heavy trucks. The pneumatic tires for vehicles according to the invention are particularly used on steering wheels and trailer wheels.

[0108] The pneumatic tire for vehicles according to the invention may have features of either the individually described embodiments of the pneumatic tire for vehicles according to the invention or a combination of features of the different described embodiments. This is particularly true because the described embodiments merely illustrate examples of pneumatic tires for vehicles according to the invention for the purpose of explaining the invention.

[0109] List of reference numerals

[0110] 1. Circumferential grooves 2. The tread of a vehicle's pneumatic tire 3. The first groove portion of the first cross section of the circumferential groove 4. The second groove portion of the first cross section of the circumferential groove 5. The third groove portion of the first cross section of the circumferential groove. 6. Bottom region of the first cross-section of the circumferential groove 13 V-shaped second section of circumferential grooves 14 Bottom region of the V-shaped second section of the circumferential groove 21. A section with a first cross-section of circumferential grooves. 22. A section with a V-shaped second cross-section and circumferential grooves. 23 Transition region between the first section and the second section 24 circumferential grooves in a section with a second cross section 33. The first groove portion of the second cross section of the circumferential groove. 34. The second groove portion of the second cross section of the circumferential groove. The third groove portion of the second cross section of the 35 circumferential groove. The fourth groove portion of the second section of the 36 circumferential grooves 37 Bottom region of the second section of the circumferential groove The lowest point of the second section of the 38 circumferential groove 40 Road 42 road water 51. Outer circumferential grooves of vehicle pneumatic tires A. Axial direction of the vehicle's pneumatic tires A1 v The opening angle of the second groove portion of the first cross section of the circumferential groove. A1 Y The angle between the straight lines on the side of the first groove section A2 Y The angle between the straight lines on the side of the fourth groove section B V,1 Width of the first groove portion of the first cross section B V,2,maxThe maximum width of the second groove portion of the first cross section B V,O The width of the first section of the circumferential groove on the surface of the tread B Y,1max The maximum width of the first groove portion of the second cross section B Y,1min Minimum width of the first groove portion of the second cross section B Y,2 The width of the second groove portion of the second cross section B Y,3 The width of the third groove portion of the second cross section B Y,O The width of the second section of the circumferential groove on the surface of the tread H1 V The height of the first groove portion of the first cross section in the radial direction R1 H1 Y The height of the first groove portion of the second cross section in the radial direction R2 H2 V The height of the second groove portion of the first cross section in the radial direction R1 H2 Y The height of the second groove portion of the second section in the radial direction R2 H4 Y The height of the fourth groove portion of the second section in the radial direction R2 L1 V The length of the portion of the first cross section on the tread surface L1 Y The distance between the segments having the first cross section on the tread surface L2 Y The length of the section with the second cross section on the tread surface L3 Y The length of the transition section between the first and second sections on the tread surface R1 Radial direction of the first cross section of the circumferential groove R2 Radial direction of the second cross section of the circumferential groove R1 V The radius of curvature of the bottom region of the first section R1 Y The radius of curvature of the bottom region of the second section R3 Y The radius of curvature of the region with the smallest distance from the tire surface in the first groove portion of the second cross section.

Claims

1. A vehicle pneumatic tire having a tread (2) having a pattern and having at least one circumferential groove (1) extending in a circumferential direction of the vehicle pneumatic tire and forming to a tread depth PT, and having an alternating first section perpendicular to the circumferential direction and a second section perpendicular to the circumferential direction on a portion (21, 24) of the circumference of the vehicle pneumatic tire, the first section being formed by at least two groove portions adjacent to each other in a first radial direction R1 of the vehicle pneumatic tire, namely, a first groove portion (3) and a radially inner second groove portion (4), the first groove portion being symmetrical about the first radial direction R1 and the first groove portion having a width B along the axial direction A of the vehicle pneumatic tire. V,1 The second groove portion on the radially inner side is wider in the axial direction A relative to the first groove portion (3) and has the largest cross-sectional area among all groove portions. The second cross-section is composed of at least two groove portions that are adjacent to each other along the second radial direction R2 of the vehicle's pneumatic tire and symmetrical about the radial direction R2, namely, the first groove portion (33) that widens outward and the second groove portion (34) that narrows inward relative to the first groove portion. The width B of the second groove portion on the inner side is less than 3 mm and varies by no more than 10%. Y,2 The variation along the axial direction A of the vehicle's pneumatic tire is no more than 10%, and the width of the second groove portion on the inner side is less than the width B of the second section on the surface of the tread in the axial direction A when the vehicle's pneumatic tire is new. Y,O 40%, wherein there is a transition region (23) between the first section and the second section, and the second groove portion (34) of the second section is at a height H2 in the radial direction R2 of the second groove portion (4) of the first section in the radial direction R1. V Extending over at least 50% of the second groove portion of the second cross section, and at a height H2 in the radial direction R2. Y At least 50% of the second groove portion of the second cross section is at a certain distance from the surface of the tread (2), the second groove portion (4) is located in the first cross section at this distance, wherein the first groove portion (33) of the second cross section widens outwardly at a constant rate, and the side of the cross section region of the first groove portion (33) of the second cross section has an inclination of 20° to 80° relative to the radial direction R2, wherein the maximum width B of the cross section region of the second groove portion (4) of the first cross section in the axial direction A is... V,2,max The average width B of the second groove portion (34) of the second cross section in the axial direction A Y,2 The ratio is between 1.5 and 4.5, where the average width B of the second groove portion of the second section in the axial direction A is... Y,2 The area is 2.5 mm to 6 mm, wherein the ratio of the area of ​​the cross-sectional region of the second groove portion (4) of the first cross-section perpendicular to the circumferential direction to the area of ​​the cross-sectional region of the second groove portion (34) of the second cross-section perpendicular to the circumferential direction is between 1.5 and 3.

2. The vehicle pneumatic tire as described in claim 1, characterized in that, The second groove portion (4) on the radial inner side of the first cross section is also symmetrical about the first radial direction R1.

3. The vehicle pneumatic tire as described in claim 1, characterized in that, The width B of the first groove portion (3) of the first cross section along the axial direction A of the vehicle's pneumatic tire. V,1 The change is no more than 2%.

4. The vehicle pneumatic tire as described in claim 1, characterized in that, The width B of the first groove portion (3) of the first cross section along the axial direction A of the vehicle's pneumatic tire. V,1 The change is no greater than 0.5%.

5. The vehicle pneumatic tire as described in claim 1, characterized in that, The width B of the second groove portion (34) of the second cross section Y,2 The variation A along the axial direction of the vehicle's pneumatic tire is no greater than 2%.

6. The vehicle pneumatic tire as described in claim 1, characterized in that, The width B of the second groove portion (34) of the second cross section Y,2 The variation A along the axial direction of the vehicle's pneumatic tire is no greater than 0.5%.

7. The vehicle pneumatic tire as described in claim 1, characterized in that, The width of the second groove portion (34) of the second section is less than the width of the second section in the axial direction A on the surface of the tread when the vehicle's pneumatic tire is new. Y,O 30%.

8. The vehicle pneumatic tire as described in claim 1, characterized in that, The width of the second groove portion (34) of the second section is less than the width of the second section in the axial direction A on the surface of the tread when the vehicle's pneumatic tire is new. Y,O 25%.

9. The vehicle pneumatic tire as described in claim 1, characterized in that, The bottom region (37) of the circumferential groove (1) is directly adjacent to the second groove portion (34) of the second section in the radial direction R2.

10. The vehicle pneumatic tire as described in claim 9, characterized in that, The maximum width B of the cross-sectional area of ​​the second groove portion (4) of the first cross-section in the axial direction A is... V,2,max The average width B of the second groove portion (34) of the second cross section in the axial direction A Y,2 The ratio is between 2.0 and 3.

5.

11. The vehicle pneumatic tire as described in claim 10, characterized in that, The maximum width B of the cross-sectional area of ​​the second groove portion (4) of the first cross-section in the axial direction A is... V,2,max The average width B of the second groove portion (34) of the second cross section in the axial direction A Y,2 The ratio is between 2.3 and 2.

8.

12. The vehicle pneumatic tire as described in claim 9, characterized in that, In the second cross section, the bottom region (37) has only one curvature, which is determined by the width B of the second groove portion of the second cross section in the axial direction A. Y,2 produce.

13. The vehicle pneumatic tire as described in claim 1, characterized in that, The third groove portion (35) is directly adjacent to the second groove portion (34) of the second cross section in the radial direction R2. The third groove portion includes the bottom region (37) of the second cross section and is teardrop-shaped. The maximum width B of the third groove portion in the axial direction A is... Y,3 The average width B of the second groove portion (34) larger than the second cross section in the axial direction A Y,2 .

14. The vehicle pneumatic tire as described in claim 13, characterized in that, The edge of the cross-sectional region of the third groove portion (35) of the second cross-section perpendicular to the circumferential direction is circular, and the diameter B of the circle is... Y,3 The average width B of the second groove portion (34) larger than the second cross section in the axial direction A Y,2 .

15. The vehicle pneumatic tire as described in claim 1, characterized in that, When the vehicle's pneumatic tire is new, the average width B of the second groove portion (34) of the second section along the axial direction A of the vehicle's pneumatic tire is... Y,2 The width B of the second section on the surface of the tread (2) in the axial direction A is smaller than the width of the second section. Y,O 15%.

16. The vehicle pneumatic tire as described in claim 15, characterized in that, When the vehicle's pneumatic tire is new, the average width B of the second groove portion (34) of the second section along the axial direction A of the vehicle's pneumatic tire is... Y,2 The width B of the second section on the surface of the tread (2) in the axial direction A is smaller than the width of the second section. Y,O 12%.

17. The vehicle pneumatic tire as described in claim 15, characterized in that, When the vehicle's pneumatic tire is new, the average width B of the second groove portion (34) of the second section along the axial direction A of the vehicle's pneumatic tire is... Y,2 The width B of the second section on the surface of the tread (2) in the axial direction A is smaller than the width of the second section. Y,O 10%.

18. The vehicle pneumatic tire as claimed in claim 1, characterized in that, The first groove portion (33) of the second cross section widens outwards at a constant rate, and the side of the cross section region of the first groove portion (33) of the second cross section has an inclination of 30° to 60° relative to the radial direction R2.

19. The vehicle pneumatic tire as described in claim 18, characterized in that, The first groove portion (33) of the second cross section widens outwards at a constant rate, and the side of the cross section region of the first groove portion (33) of the second cross section has an inclination of 40° to 50° relative to the radial direction R2.

20. The vehicle pneumatic tire as claimed in claim 1, characterized in that, The ratio of the area of ​​the cross-sectional region perpendicular to the circumferential direction of the second groove portion (4) of the first cross-section to the area of ​​the cross-sectional region perpendicular to the circumferential direction of the second groove portion (34) of the second cross-section is between 1.5 and 2.

5.

21. The vehicle pneumatic tire as described in claim 20, characterized in that, The ratio of the area of ​​the cross-sectional region perpendicular to the circumferential direction of the second groove portion (4) of the first cross-section to the area of ​​the cross-sectional region perpendicular to the circumferential direction of the second groove portion (34) of the second cross-section is between 2 and 2.

3.

22. The vehicle pneumatic tire as described in claim 1, characterized in that, In the at least one circumferential groove (1), in the transition region (23) between the portion (21) having the first cross section and the portion (24) having the second cross section, the cross section of the circumferential groove (1) is V-shaped.

23. The vehicle pneumatic tire as claimed in any one of claims 1 to 22, characterized in that, The vehicle's pneumatic tires are multi-purpose vehicle tires.

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