AIR TIRES WITH CIRCULATION GROOVE

Description

[0001] The invention relates to a pneumatic vehicle tire, in particular a commercial vehicle tire, with a tread having a profile and at least one circumferential groove running in the circumferential direction of the pneumatic vehicle tire and designed to a tread depth PT, which groove is composed, at least over at least a partial section of the circumference of the pneumatic vehicle tire in cross section perpendicular to the circumferential direction, of at least two groove sections adjoining one another in a radial direction R of the pneumatic vehicle tire, a first groove section which is symmetrical to a line running in the radial direction R of the pneumatic vehicle tire, the width of which first groove section in the axial direction A of the pneumatic vehicle tire is less than 3 mm and does not vary by more than 10%, preferably does not vary by more than 2% and particularly preferably does not vary by more than 0.5%, and a radially inner,second groove section which is wider in axial direction A than the first groove section and has the largest cross-sectional area of ​​all groove sections. State of the art

[0002] It is known and common practice to provide circumferential grooves running in the circumferential direction in the tread of pneumatic commercial vehicle tires. Such circumferential grooves separate circumferential ribs from one another, which ribs can be provided with further grooves, for example transverse grooves, which give the circumferential ribs a block-like structure. Circumferential grooves with a cross-section perpendicular to the circumferential direction of the pneumatic commercial vehicle tire, which only has one groove section in the radial direction R, are widespread in treads of pneumatic commercial vehicle tires. For a tire, the radial direction R is the direction that points outwards perpendicular to the axis of rotation of the tire, which defines the axial direction A of the tire, i.e. the center of the tire or the hub of the rim carrying the tire. The centrifugal force acts on the tire in this direction when a wheel fitted with the pneumatic commercial vehicle tire rotates.A groove section in the radial direction R of a cross-section of a circumferential groove perpendicular to the tire's circumferential direction is characterized by a specific geometric shape of the cross-section of the groove section perpendicular to the tire's circumferential direction, which is clearly different from the geometric shape of the cross-section of another groove section perpendicular to the tire's circumferential direction. Therefore, if a circumferential groove has only one groove section in the radial direction R, its cross-section perpendicular to the tire's circumferential direction can be described by a geometric shape. Circumferential grooves with only one groove section, for example, have a V-shaped or U-shaped cross-section perpendicular to the tire's circumferential direction.

[0003] The cross-section of a circumferential groove may have a deepest point at its base, where the distance to the tread surface is greatest. This corresponds to the tread depth PT of the circumferential groove when the groove is unused. The base of the circumferential groove is the area of ​​the circumferential groove where, viewed from the tire tread surface, the groove is at its deepest, or it represents the innermost area of ​​the circumferential groove, since this is where the distance from the circumferential groove to the center of the tire or the hub of the wheel supporting the tire is smallest.This innermost area of ​​a circumferential groove, its base area, comprises the deepest point of a cross-section of the circumferential groove that has the greatest distance from the tread surface—the tread depth PT when the pneumatic vehicle tire is new—and the area of ​​the circumferential groove whose distance from the tread surface is greater than 90% of the tread depth PT when the pneumatic vehicle tire is new. The deepest point of a cross-section in the base area of ​​a circumferential groove can be exactly one point on the edge of the circumferential groove. However, it is equally possible that there is no deepest point in the cross-section of the circumferential groove, but rather a straight line in the base area of ​​the circumferential groove.In the case of a cross-section perpendicular to the circumferential direction, this straight line extends in the axial direction A over a certain length, runs parallel to the surface of the tread and is at its greatest distance from the tread surface, which corresponds to the tread depth PT in an unused tire. The edge of the cross-section of the circumferential groove perpendicular to the circumferential direction then has two sides in the axial direction A of the tire, also referred to as the axial direction, which abut one another at a single lowest point in the base area of ​​the circumferential groove and are arranged to the side of this straight line in the axial direction at a straight line in the base area of ​​the circumferential groove that is at the greatest distance between the circumferential groove and the tread surface. If a circumferential groove is not arranged axially centrally in the tread of a tire, one side of the circumferential groove points towards the center of a pneumatic vehicle tire and the other to the outside of a pneumatic vehicle tire.Both sides are defined by groove flanks that typically form an angle with the radial direction R. This angle can vary depending on the depth of the circumferential groove, but is often constant over at least a certain range of the depth of the circumferential groove, i.e., the distance of the circumferential groove from the tread surface. The edge of one side of the circumferential groove is then formed by a straight line that is perpendicular to the circumferential direction and forms a constant angle with the radial direction R. A groove section in which the sides of the circumferential groove run almost or exactly parallel to the radial direction has a U-shaped profile. In this groove section, the tangent of the sides perpendicular to the circumferential direction forms an angle with the radial direction that is not greater than 10°. In particular, the tangent can run parallel to the radial direction.

[0004] If, however, the two sides converge at an angle of greater than 10° relative to the radial direction R within a groove section as the depth of the circumferential groove increases, the groove section has a V-shaped cross-section. With a precise V-shaped cross-section, the angle is constant across the depth of the circumferential groove, so that the groove flanks of the cross-section are straight lines.

[0005] Typically, the shape of the groove flanks on both sides of the circumferential groove is the same, so that the cross-section of the circumferential groove perpendicular to the circumferential direction is symmetrical to the radial direction R.

[0006] In the case of a U-shaped cross-section, the groove has in its lowest area, the groove base, either a very slight curvature with a deepest point at which the distance to the surface of the tread corresponds to the tread depth PT of an unused groove or an area in the axial direction at which the distance to the surface of the tread corresponds to the tread depth PT of an unused tire.

[0007] In a V-shaped cross-section, however, both sides of a circumferential groove can converge directly at the deepest point of the circumferential groove.

[0008] A tread of a pneumatic commercial vehicle tire can also have circumferential grooves with a cross-section perpendicular to the circumferential direction of the pneumatic commercial vehicle tire, with only one groove section in the radial direction R, wherein the cross-section is not symmetrical to the radial direction R. Pneumatic vehicle tires with circumferential grooves that have such a cross-section perpendicular to the circumferential direction of the pneumatic commercial vehicle tire are known from DE 10 2005 042 903 A1. Both sides of the disclosed circumferential grooves are formed as groove flanks that are designed as straight lines above the base region of the circumferential groove, forming a small angle of inclination relative to the radial direction R. These small angles of inclination (α and β) are different on both sides of the groove. The straight sections of the groove flanks on both sides of the circumferential grooves extend to the surface of the tread of the pneumatic vehicle tire shown.Very similar circumferential grooves are also described in WO 2017 / 176280 A1. The circumferential grooves shown differ only in which side of the circumferential groove, the side facing the center of a pneumatic vehicle tire or the side facing the outside of a pneumatic vehicle tire, has the smaller angle of inclination relative to the radial direction R. In the circumferential groove described in DE 10 2005 042 903 A1, the side facing the center of a pneumatic vehicle tire preferably has the smaller angle of inclination. Due to the larger angle of inclination of the side of the circumferential groove facing the outside of the pneumatic vehicle tire, the profile of the tread towards the outside receives increased transverse stiffness. In addition, the larger angle of inclination results in less compression in the groove base facing the outside of the pneumatic vehicle tire, thus reducing the risk of groove breakage in this area.

[0009] However, much more complex designs of the cross sections perpendicular to the circumferential direction of circumferential grooves are also known, wherein the cross section can be composed of two or three groove sections adjoining one another in a radial direction R of the pneumatic vehicle tire.

[0010] In known embodiments, the cross section comprises a first groove section which is symmetrical to the radial direction R of the pneumatic vehicle tire and whose width is constant in the axial direction A, and a radially inner second groove section which adjoins this in the radial direction and is wider than the first groove section in the axial direction A and which comprises the bottom region of the circumferential groove.

[0011] In such a known form of such circumferential grooves 1 in a tread 2 of a pneumatic vehicle tire, an example of which is shown in Figure 1As shown, its cross-section perpendicular to the circumferential direction also has an outer third groove section 3 which widens outwards and is symmetrical to the radial direction R of the pneumatic vehicle tire. This third outer first groove section 3 is followed in the radial direction (opposite the direction of the arrow) by a first groove section 4. This is narrower in the axial direction A than the third groove section 3 and symmetrical to the radial direction R of the pneumatic vehicle tire. This first groove section 4 is followed in the radial direction (opposite the direction of the arrow) by a second groove section 5. This radially inner groove section 5 has a cross-section which is wider in the axial direction A than the first groove section 4.

[0012] Such circumferential grooves of a pneumatic vehicle tire are known from US 2,843,172. Here, the third groove section, which widens outwards, is symmetrical to the radial direction R of the pneumatic vehicle tire only in certain positions around the circumference of the pneumatic vehicle tire, since this groove section has a twisted shape in the axial direction A over the circumference, which can be sinusoidal or zigzag. The first groove section has a reduced width in the axial direction A compared to this third groove section and is symmetrical to the radial direction R of the pneumatic vehicle tire. A radially inner second groove section can have a cross-section that is wider in the axial direction A than the first groove section and is likewise symmetrical to the radial direction R of the pneumatic vehicle tire. The edge of the cross-section perpendicular to the circumferential direction has an angular shape in the base region of the circumferential groove.The width of the circumferential groove in the axial direction remains virtually unchanged over most of the height of the second groove section in the radial direction, after initially the width of the cross-section of the second groove section perpendicular to the circumferential direction of the tire in the axial direction A has constantly increased with increasing distance from the tread surface up to a maximum width. In this region of the second groove section, the edge of the cross-section of the second groove section is formed by a straight line. The height of a groove section is the maximum extension of the groove section in the radial direction R.The region of almost unchanged width forms the innermost region of the second groove section, which has the greatest distance from the surface of the tread of the pneumatic vehicle tire, and therefore also includes the bottom region of the circumferential groove, which is formed by an area in the axial direction A where the distance to the surface of the tread corresponds to the tread depth PT of the circumferential groove in an unused groove. In this innermost region, too, the edge of the cross-section of the second groove section is formed by a straight line on both sides, so that the groove flanks of the second groove section have a contour perpendicular to the circumferential direction of the tire that essentially consists of two straight sections. The inner straight sections of the groove flanks form corners with the surface of the bottom region.

[0013] A pneumatic vehicle tire of the type mentioned above is known from DE 10 2017 208 010 A1. Disclosed is a pneumatic vehicle tire with a tread having circumferential grooves. The cross-section of the circumferential groove, perpendicular to the circumferential direction, has an outer third groove section whose cross-section is funnel-shaped and symmetrical to the radial direction R of the pneumatic vehicle tire. This outer third groove section is adjoined in the radial direction by a first groove section with a constant width in the axial direction A, which corresponds to the smallest width in the axial direction A of the third groove section. This first groove section is also symmetrical to the radial direction R of the pneumatic vehicle tire. This first groove section is adjoined in the radial direction R by a second inner groove section. It has a cross-section that is wider in the axial direction A than the first groove section.It has two ceiling flanks, through which the width of the second groove section widens in the axial direction A with increasing distance from the surface of the tread of the tire shown, symmetrical to the radial direction R, up to a maximum value. With further increasing distance from the tread surface, the width of the groove section then slowly decreases in the axial direction until the bottom region of the groove is reached, at which the maximum tread depth PT of the groove is present. The cross-section of the second groove section has straight lines on its edge on both sides of the groove section, arranged perpendicular to the circumferential direction symmetrically to the radial direction R, which converge towards one another at a small angle of inclination to the radial axis R with increasing distance from the tread surface until they reach the bottom region of the groove section, which is formed by a surface perpendicular to the radial direction R in the axial direction A.The angle of inclination of the incoming straight line to the radial direction R is typically in the range of 5° to 25°.

[0014] The previously described circumferential grooves, which comprise three consecutive groove sections in the radial direction, have reduced rolling resistance due to the narrow central groove section in the axial direction R. This is because the flanks of the circumferential groove in this groove section touch when the flanks of the circumferential groove make contact with the road surface, thereby preventing further radial deformation in the tread of the pneumatic tire in the circumferential groove area due to the vehicle weight. Furthermore, the contact pressure in this area is reduced by the contact of the groove flanks, which leads to a reduction in tire wear.

[0015] In addition, the previously described circumferential grooves exhibited good drainage properties due to the large cross-section of the inner second groove section. This improves the aquaplaning behavior of the pneumatic vehicle tire with increasing tread wear.

[0016] The problem of groove breakage, which is particularly prevalent in the shoulder area of ​​pneumatic vehicle tires and thus in the outer grooves arranged on the outside in the tread of the pneumatic vehicle tire in the axial direction, has so far been solved in the circumferential grooves described above, which have three groove sections following one another in the radial direction, by providing sipes, i.e. incisions that are usually arranged at regular intervals on the outer surface of the tread. However, with increasing wear of the tread of the pneumatic vehicle tire over the course of use, the sipes on the surface are also worn away. Accordingly, the risk of groove breakage increases with increasing tire wear due to the associated wear of the tread.

[0017] Likewise, circumferential grooves with a cross-section perpendicular to the circumferential direction are known in a pneumatic vehicle tire that comprises only the first and second groove sections. Due to a narrow width of the first groove section, the second groove section can become a channel that is no longer connected to the tread surface when the first groove section comes into contact with the road. As shown in US 2018 / 0244111 A1, openings can then be provided in the circumferential groove to allow water from the road surface to flow into the channel of the second groove section in wet conditions, thereby reducing the risk of aquaplaning.

[0018] In general, a circumferential groove as described above, whose cross-section is made up of at least two groove sections perpendicular to the circumferential groove, will exhibit varying levels of aquaplaning behavior depending on the amount of tire wear and the resulting remaining tread depth. Initially, an outer third groove section, if present, may result in initial aquaplaning behavior, but this may only partially match the performance of an open circumferential groove, e.g. one with a U-shaped profile. If, on the other hand, the first groove section is directly on the surface of the tread of the pneumatic tire, particularly due to tire rubber wear, the circumferential groove no longer contributes to positive aquaplaning behavior because the flanks of the first groove section then collide when the circumferential groove comes into contact with the road surface.The water on the road surface cannot then penetrate the first groove section into the larger cross-section of the inner second groove section, which would immediately significantly reduce aquaplaning. This only occurs when the first groove section is at least almost completely or completely worn away. Then, the inner second groove section represents an open circumferential groove, whose cross-section can absorb a large amount of water from the road surface, thereby significantly reducing the risk of aquaplaning.

[0019] US 2018 / 0147894 A1 discloses a pneumatic vehicle tire with a tread having four circumferential grooves configured to the tread depth and two circumferentially extending outer grooves configured in the shoulder-side tread ribs. Each outer groove has a depth of 30% to 150% of the tread depth in the radial direction and, viewed in cross-section, is composed of a radially outer groove section and a radially inner groove section. The radially outer groove section is symmetrical with respect to a line running in the radial direction and has a width of 0.3 mm to 5.0 mm, for example 2.0 mm. The radially inner groove section is expanded in the axial direction (axial direction) compared to the radially outer groove section and has a drop-shaped cross-sectional area that is asymmetrical to the line running in the radial direction.The cross-sectional area of ​​the second groove section of the outer groove is asymmetrical to the radial line, extends on both sides of the radial line and has a cornerless edge at the bottom area.

[0020] US 2018 / 0162176 A1 discloses a pneumatic vehicle tire with a tread having outer grooves with a depth of 30% to 150% of the tread depth. The outer grooves, viewed in cross-section, are composed of a radially outer groove section and a radially inner groove section. The radially outer groove section is symmetrical with respect to a line running in the radial direction and runs in the radial direction. The radially inner groove section has a circular cross-section and, according to one embodiment, is offset from the radially outer groove section toward the tread center, so that the cross-sectional area of ​​the radially inner groove section lies between a line running in the radial direction and centrally through the radially outer groove section and the side of the outer groove facing the center of the vehicle tire. largeris defined as the cross-sectional area of ​​the radially inner groove portion between the line extending in the radial direction and the side of the circumferential groove facing the outside of the pneumatic vehicle tire.

[0021] JP2002079809 A, US 2010 / 0116395 A1, and WO 2014 / 178186 A1 each disclose a pneumatic vehicle tire with a tread having outer grooves. These grooves, viewed in cross-section, are composed of a radially outer groove section and a channel-shaped, radially inner groove section. The radially inner groove section is asymmetrical with respect to a line running in the radial direction and is defined by a base region with four sections. The sections extend along radii, with three of the sections curved outwards and one of the sections curved inwards.

[0022] The invention is based on the object of providing circumferential grooves for a pneumatic vehicle tire that continue to have the advantages of previously known circumferential grooves, which have at least two groove sections following one another in the radial direction, and additionally have an improved cross-sectional profile in the circumferential direction that better prevents groove breakage. In particular, the improved structure of the circumferential grooves is intended to reduce the increased risk of groove breakage in the shoulder area of ​​tires. Above all, the improved cross-sectional profile is also intended to reduce the risk of groove breakage when a pneumatic vehicle tire has been in use for an extended period. Firstly, the sipes on the surface are then largely worn away.Above all, the tire's repeated, even rolling motion and the associated constant alternation of compression and tension in the groove base facing the shoulder significantly increase the risk of groove fractures in this area. In addition, the shoulder area of ​​the tire is particularly stressed during cornering due to the significant transfer of lateral forces.

[0023] The problem of groove breakage is particularly acute in commercial vehicles. Due to the high weight of the vehicles, which can be further increased by the weight of the transported load depending on their use, very large weight forces act on the tread of commercial vehicle tires, especially the tread blocks. The problem is particularly acute in commercial vehicle steering axle tires, which are constantly subjected to the same alternating compression and tension. This is further exacerbated when the commercial vehicles are used primarily or exclusively for long-distance transport. Summary of the invention

[0024] The problem is solved by pneumatic vehicle tires, in particular commercial vehicle tires, according to patent claim 1.

[0025] It has been shown that such an area ratio best takes into account the different loads on the sides of the circumferential groove, especially if the edge of the second groove section is designed according to the criteria described above.

[0026] Such a pneumatic vehicle tire is a pneumatic vehicle tire with a tread having a profile and at least one circumferential groove running in the circumferential direction of the pneumatic vehicle tire and designed to a tread depth PT, which groove is composed, at least over at least a partial section of the circumference of the pneumatic vehicle tire in cross section perpendicular to the circumferential direction, of at least two groove sections adjoining one another in a radial direction R of the pneumatic vehicle tire, a first groove section symmetrical to the radial direction R of the pneumatic vehicle tire, the width of which in the axial direction of the pneumatic vehicle tire is less than 3 mm and does not vary by more than 10%, preferably does not vary by more than 2% and particularly preferably does not vary by more than 0.5% and a radially inner,a second groove section which is wider than the first groove section in the axial direction of the pneumatic vehicle tyre and has the largest cross-sectional area of ​​all groove sections, the cross-sectional area of ​​which is asymmetrical to the radial direction R, extends on both sides of the radial direction R and has a cornerless edge in the bottom region of the circumferential groove.

[0027] The tread of the pneumatic vehicle tire thus has a profile that includes at least one, usually several, circumferential grooves extending in the circumferential direction of the pneumatic vehicle tire. At least one of these circumferential grooves is designed to a profile depth (PT) and has a cross-section perpendicular to the circumferential direction, at least over a partial section of the circumference of the pneumatic vehicle tire, which cross-section is composed of at least two groove sections adjoining one another in a radial direction R of the pneumatic vehicle tire.

[0028] This circumferential groove then has the same tread depth across the entire tire circumference, with a tolerance of typically 0.10 to 0.15 mm, which is only dependent on manufacturing. Only if tread wear indicators are arranged in the circumferential groove can the tread depth at these locations deviate by the height of the wear indicators. The height of a wear indicator can be 1.2 mm, for example. Wear indicators can be, for example, transverse ribs in a circumferential groove at the base of the groove, evenly arranged around the tire circumference.

[0029] If the at least one circumferential groove running in the circumferential direction of the pneumatic vehicle tire and designed to a tread depth PT comprises several circumferential grooves, these can have the same or different tread depths, which, however, as explained above, are the same over the tire circumference for one circumferential groove.

[0030] The at least two adjacent groove sections are located directly behind one another in a radial direction R of the pneumatic vehicle tire as parts of a cross-section of a circumferential groove of the pneumatic vehicle tire. A pneumatic vehicle tire according to the invention can also have further circumferential grooves that do not have such groove sections or only have differently designed groove sections.

[0031] The first of the two groove sections has a width in the axial direction of the pneumatic vehicle tire that is less than 3 mm. This width varies by no more than 10%, preferably no more than 2%, and particularly preferably no more than 0.5%. In a preferred embodiment, the width of the first groove section is even constant in the axial direction. Deviations are then solely due to the limitations of the manufacturing possibilities of the circumferential grooves in the pneumatic vehicle tire. The resulting tolerance of the width of the first groove section is typically less than 0.2 mm, preferably less than 0.15 mm, and particularly preferably less than 0.05 mm. This first groove section is symmetrical to the radial direction R of the pneumatic vehicle tire.The symmetry of the first groove section to the radial direction R then determines exactly for the circumferential groove in which radial direction its at least two groove sections adjoin one another.

[0032] The narrow width of the first groove section in the axial direction, which is less than 3 mm, ensures that the sides of the first groove section touch when a cross-section of the circumferential groove comes into contact with the road due to the vehicle weight compressing the tread rubber, thereby preventing further radial deformation in this area of ​​the circumferential groove. This significantly reduces the rolling resistance of the pneumatic vehicle tire. In addition, the contact pressure on the tread surface in this area is reduced by the contact of the groove flanks, which leads to a reduction in tire wear. To reliably achieve this effect, a width of the first groove section in the axial direction of 0.5 mm to 2.8 mm, preferably of 0.75 mm to 2.25 mm, and particularly preferably of 1.1 mm to 1.4 mm is typically selected.

[0033] The second groove section is arranged radially inwardly from the first groove section along the radial direction R. It is wider than the first groove section in the axial direction A and has the largest cross-sectional area perpendicular to the circumferential direction of all the groove sections of the circumferential groove. In contrast to the first groove section, the cross-sectional area of ​​the second groove section is asymmetrical to the radial direction R. It extends on both sides of the radial direction R, which belongs to the circumferential groove, and has a cornerless edge in the bottom region of the circumferential groove formed by the second groove section. This means that there is no point on the edge of the cross-section in the bottom region of the circumferential groove where two straight sides abut one another or where the angle of inclination to the radial direction changes discontinuously, i.e. abruptly.

[0034] Due to the asymmetry of the cross-sectional area perpendicular to the circumferential direction of the second groove section relative to the radial direction R in one or more circumferential grooves of the pneumatic vehicle tire according to the invention, the risk of groove breakage in these circumferential grooves can be reduced, since the contour of the edge of the cross-sectional area perpendicular to the circumferential direction of the second groove section is now correspondingly designed on both sides of the circumferential groove in the axial direction A when the circumferential grooves are subjected to different loads. The risk of groove breakage is also reduced in particular by the fact that the edge of the cross-sectional area perpendicular to the circumferential direction of the second groove section has no corners, at least in the base region, with the contour being designed differently on both sides of the radial direction R.This requirement for the contour of the edge of the cross-sectional area perpendicular to the circumferential direction avoids weak points for groove breakage caused by the discontinuity of an edge in the tread material, a rubber compound.

[0035] In an advantageous development of the invention, it is provided that the edge of the cross-sectional area of ​​the second groove section in the base region of the circumferential groove only has curves. In this case, the edge in the base region of the circumferential groove has curves with different curvatures, which are described by a radius of curvature. In particular, the edge has curves with a constant curvature or a constant radius of curvature over a certain length of the edge. In the region of constant curvature, the edge then corresponds to an arc of a circle with the associated constant radius of curvature. In this case, the arc can typically encompass an angular range of the circle of up to 90°. The angular range of the arc is often in the range of 30° to 75°, preferably between 45° and 60°.However, the angular range of the circular arc can also have a relatively small value and cover less than 30 ° of the circle, even less than 20 ° and 10 °.

[0036] In another advantageous development of the invention, it is provided that the edge of the cross-sectional area of ​​the second groove section in the base region of the circumferential groove has only curves and straight lines. In such a configuration, the edge also has curves with different curvatures, which are described by a radius of curvature. In particular, the edge has curves with a constant curvature or a constant radius of curvature over a certain length of the edge. The angular ranges of a circular arc thus created can have the same values ​​as in the previously described development. In this embodiment, however, the edge of the cross-sectional area of ​​the second groove section additionally has at least one straight line perpendicular to the circumferential direction in the base region of the circumferential groove.

[0037] In the bottom area of ​​the circumferential groove, there may be a straight line running in the axial direction A. Its distance from the surface of the tread corresponds to the profile depth PT for an unused groove.

[0038] The edge of the second groove section may also have a straight line on one or both of its sides of the circumferential groove.

[0039] In a further preferred embodiment, in the bottom region of the circumferential groove, the side of the circumferential groove has a curvature with the smallest radius of curvature, which faces the center of the pneumatic vehicle tire. In the case of a circumferential groove that is not arranged axially centrally in the tread, the side of the circumferential groove that faces the center of the pneumatic vehicle tire has a different curvature in the bottom region of the circumferential groove than the side of the circumferential groove that faces the outside of the pneumatic vehicle tire. The side of the circumferential groove that faces the center of the pneumatic vehicle tire has a greater curvature with a smaller radius of curvature. The correspondingly smaller curvature of the side of the circumferential groove that faces the outside of the pneumatic vehicle tire increases the transverse rigidity of this side and thus reduces the risk of groove breakage on this side.

[0040] In the bottom region of the circumferential groove on the side of the circumferential groove facing the center of the pneumatic vehicle tire, the smallest radius of curvature of the curvature is typically at least 20% smaller than the smallest radius of curvature of the curvature of the other side, preferably at least 35% smaller than the smallest radius of curvature of the curvature of the other side, and particularly preferably at least 50% smaller than the smallest radius of curvature of the curvature of the other side.

[0041] Preferably, one of the circumferential grooves running in the circumferential direction of the pneumatic vehicle tire, designed to a profile depth PT, which has a cross-section perpendicular to the circumferential direction at least in a partial section of the circumference, which is composed of at least two groove sections adjoining one another in a radial direction R of the pneumatic vehicle tire and having the properties described above, is an outer groove of a pneumatic vehicle tire according to the invention.

[0042] In a further embodiment, both outer grooves of a pneumatic vehicle tire according to the invention are such circumferential grooves.

[0043] In a further embodiment, a pneumatic vehicle tire according to the invention has only one such circumferential groove, which forms one of the two outer grooves of the pneumatic vehicle tire.

[0044] In a further advantageous embodiment of a pneumatic vehicle tire according to the invention, the second groove section of the cross section composed of at least two groove sections has a cross-sectional area perpendicular to the circumferential direction, in which the cross-sectional area starting from the bottom region of the circumferential groove is asymmetrical to the radial direction R over at least 35% of the height of the second groove section in the radial direction R, preferably the cross-sectional area starting from the bottom region of the circumferential groove is asymmetrical to the radial direction R over at least 50% of the height of the second groove section in the radial direction R, and particularly preferably the cross-sectional area starting from the bottom region of the circumferential groove is asymmetrical to the radial direction R over at least 70% of the height of the second groove section in the radial direction R.

[0045] The symmetry of the first groove section to the radial direction R determines exactly for the circumferential groove in which radial direction R its at least two groove sections adjoin one another. The height of the second groove section in the radial direction R is defined as the maximum height of the cross-sectional area in the direction of the radial direction R and is given by the maximum distance between two points on the edge of the cross-sectional area that they have in the radial direction R only. Their distance perpendicular to the radial direction is not considered here. The asymmetry of the cross-sectional area to the radial direction R exists over a certain proportion of the height of the second groove section in the radial direction R.The asymmetrical region begins at the bottom area of ​​the circumferential groove, which is also the bottom area of ​​the second groove section, and extends from this area over a certain proportion of the height of the second groove section in the radial direction R. The asymmetry of the second groove section in its bottom area and a further proportion of the cross-section in the radial direction R is very advantageous for preventing groove breakage. The larger the proportion of the asymmetrical cross-section, the more the circumferential groove can accommodate different loads caused by forces on its two sides in the axial direction A. This is generally the more the case, the greater the difference between the smallest radii of curvature on both sides of the circumferential groove in the bottom area of ​​the circumferential groove.

[0046] Typically, the second groove section is asymmetrical to the radial direction R over a height of at least 3 mm, preferably over a height of 4 mm and particularly preferably a height of 5 mm in the radial direction R starting from the deepest point of the circumferential groove.

[0047] In one embodiment of the pneumatic vehicle tire according to the invention, in the radially inner region of the second groove section, which is asymmetrical to the radial direction R, the cross-sectional area of ​​the second groove section between the radial direction R and the side of the circumferential groove facing the center of the pneumatic vehicle tire is 15% smaller to 45% larger, preferably 5% smaller to 35% larger and particularly preferably 25% to 32% larger than the cross-sectional area of ​​the second groove section between the radial direction R and the side of the circumferential groove facing the outside of the pneumatic vehicle tire.

[0048] Therefore, the radially inner region of the second groove section, which is asymmetric to the radial direction R and has these cross-sectional areas, begins at the bottom region of the circumferential groove and extends from this region over a corresponding distance of the second groove section in the radial direction R.

[0049] In one embodiment of the pneumatic vehicle tire according to the invention, the edge of the cross-sectional area of ​​the second groove section has a straight line on both sides of the circumferential groove which runs inwards towards the radial direction R, wherein the straight line of the side of the circumferential groove which points towards the centre of the pneumatic vehicle tire has a smaller inclination with respect to the radial direction R than the straight line of the side of the circumferential groove which points towards the outside of the pneumatic vehicle tire.

[0050] For the straight lines of the two sides of the circumferential groove, which run inwards towards the radial direction R, the distance to the radial direction R, which is defined by the symmetry of the first groove section, decreases with increasing distance from the surface of the tread of the pneumatic vehicle tire.

[0051] Typically, the angle of inclination of the straight line of the side of the circumferential groove facing the outside of the pneumatic vehicle tire is 8 to 100 times, preferably 12 to 30 times, and particularly preferably 17 to 20 times greater than the angle of inclination of the straight line of the side of the circumferential groove facing the center of the pneumatic vehicle tire, relative to the radial direction R. Typically, the angle of inclination of the straight line of the side of the circumferential groove facing the center of the pneumatic vehicle tire has a value of 0° to 15°, preferably a value of 4° to 11°, and particularly preferably a value of 6° to 9°. Typically, the angle of inclination of the straight line of the side of the circumferential groove facing the outside of the pneumatic vehicle tire has a value of 10° to 45°, preferably a value of 15° to 35°, and particularly preferably a value of 25° to 32°.

[0052] The greater inclination of the straight line of the side of the circumferential groove facing the outside of the pneumatic vehicle tire increases the transverse stiffness of that side and thereby reduces the risk of groove breakage on that side.

[0053] In one embodiment of the pneumatic vehicle tire according to the invention, the edge of the cross-sectional area of ​​the second groove section on the side of the circumferential groove facing the outside of the pneumatic vehicle tire has a straight line with a length that is less than 40% of the height of the second groove section in the radial direction R , preferably less than 20% of the height of the second groove section in the radial direction R and particularly preferably less than 10% of the height of the second groove section in the radial direction R .

[0054] In a preferred embodiment of the pneumatic vehicle tire according to the invention, the edge of the cross-sectional area of ​​the second groove portion has a straight line tapering inward toward the radial direction only on the side of the circumferential groove facing the center of the pneumatic vehicle tire.

[0055] Configuring the side of the circumferential groove facing the center of the pneumatic vehicle tire with a straight line that preferably has a small angle of inclination relative to the radial direction R, as described above, can be advantageous on this side, since the focus here is not on the transverse rigidity of the adjacent tread blocks of the tread, but rather on the ability of the shape of the second groove section to absorb water in wet road conditions and thus improve the drainage properties of the circumferential groove. Such a design therefore ensures both increased stability of the tread of the pneumatic vehicle tire and good wet performance of the pneumatic vehicle tire, which in particular appropriately reduces the risk of aquaplaning.

[0056] In one embodiment of the pneumatic vehicle tire according to the invention, the cross-sectional area of ​​the second groove section perpendicular to the circumferential direction has a maximum width perpendicular to the radial direction R, which is 20% smaller to 50% larger, preferably 5% smaller to 35% larger and particularly preferably 10% to 17% larger than the maximum height of the cross-sectional area in the direction of the radial direction R. The maximum width of the cross-sectional area of ​​the second groove section is defined as the maximum distance between two edge points of the edge of the cross-sectional area, which they have from each other only in the axial direction A. In other words: the two edge points that define the maximum width of the second groove spacing are the two points on both sides of the second groove section that each have the greatest distance from the radial direction R.The maximum width of the second groove spacing is then the sum of the distances of the two points to the radial direction R which have the greatest distance to the radial direction R. In this case, it is usually the case that the two points do not have the same distance to the surface of the tread of the pneumatic vehicle tire, ie they are at the same tread depth.

[0057] Preferably, the point with the greatest distance to the radial direction R on the side facing the outside of the pneumatic vehicle tire has a greater tread depth than the point with the greatest distance to the radial direction R on the side facing the center of the pneumatic vehicle tire. The difference in the tread depth between the two points is typically 0.5% to 15% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R, preferably 1% to 6% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R, and particularly preferably 2% to 3% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R.The distance of the edge point of the cross-sectional area of ​​the second groove section perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side facing the outside of the pneumatic vehicle tire to the deepest point of the circumferential groove in the radial direction R is typically 30% to 80% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R, preferably 50% to 75% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R and particularly preferably 55% to 65% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R.The distance of the edge point of the cross-sectional area of ​​the second groove section perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side facing the center of the pneumatic vehicle tire to the deepest point of the circumferential groove in the radial direction R is typically 50% to 80% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R, preferably 55% to 75% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R and particularly preferably 60% to 70% of the maximum height of the cross-sectional area of ​​the second groove section in the direction of the radial direction R.

[0058] Preferably, the distance to the radial direction R of the edge point of the cross-sectional area of ​​the second groove section perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side facing the outside of the pneumatic vehicle tire is greater than the distance to the radial direction R of the edge point of the cross-sectional area of ​​the second groove section perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side facing the center of the pneumatic vehicle tire. Typically, the distance to the radial direction R of the edge point with the greatest distance to the radial direction R on the side facing the outside of the pneumatic vehicle tire is 5% to 35% greater, preferably 8% to 25% greater, and particularly preferably 12% to 18% greater than the distance to the radial direction R of the edge point with the greatest distance to the radial direction R on the side facing the center of the pneumatic vehicle tire.

[0059] By positioning the edge points with the greatest distance to the radial direction R on the two sides of the second groove section, as mentioned above, both good transverse stiffness of the profile of the tread of the pneumatic vehicle tire on the side of the circumferential groove facing the outside of the pneumatic vehicle tire and good wet performance of the pneumatic vehicle tire are achieved.

[0060] In one embodiment of the pneumatic vehicle tire according to the invention, in at least one of the at least one circumferential grooves running in the circumferential direction of the pneumatic vehicle tire, the cross section perpendicular to the circumferential direction in the at least one partial section of the circumference of the pneumatic vehicle tire, starting at the tread outer surface, is composed of only three groove sections adjoining one another in a radial direction R of the pneumatic vehicle tire, wherein a third outer groove section widens outwards and is symmetrical to the radial direction R of the pneumatic vehicle tire and the first groove section narrows in axial direction A compared to the third groove section.

[0061] This third groove section adjoins the first groove section radially outward and ends at the surface of the tread of the pneumatic vehicle tire. It widens outward, i.e., toward the outer surface of the tread, and, like the first groove section, is symmetrical to the radial direction R of the pneumatic vehicle tire. The first groove section is narrower than the third groove section.

[0062] Preferably, the cross-section of the outer third groove section expands uniformly outward perpendicular to the circumferential direction. As a result, the cross-section of the outer third groove section has the shape of an isosceles and thus symmetrical trapezoid.

[0063] Typically, the third groove section of a new pneumatic vehicle tire initially has a width in the axial direction A of 2.5 mm to 5.0 mm on the surface of the tread, preferably a width of 3.5 mm to 4.6 mm, and particularly preferably a width of 3.75 mm to 4.25 mm. In the radial direction R toward the wheel axis, the third groove section then typically tapers to a width in the axial direction A of 0.8 mm to 2.5 mm, preferably a width of 1.0 mm to 1.7 mm, and particularly preferably to a width of 1.1 mm to 1.4 mm.

[0064] Typically, the two sides of the cross-section of the third groove section perpendicular to the circumferential direction, when the third groove section widens uniformly outwards, have an angle of inclination of 25 ° to 45 °, preferably of 30 ° to 40 ° and particularly preferably of 33 ° to 37 ° with respect to the radial direction R. Due to the inclination of the sidewalls, the first groove section is able to absorb water in wet conditions and thus improve the wet performance of the pneumatic vehicle tire.

[0065] In one embodiment of the pneumatic vehicle tire, a third outer groove section having the aforementioned properties is present in all of the at least one circumferential groove running in the circumferential direction of the pneumatic vehicle tire, so that in the partial sections of the circumference of the pneumatic vehicle tire in which the cross section is composed of the at least two groove sections, the cross section of the circumferential grooves perpendicular to the circumferential direction is composed only of the three groove sections adjoining one another in the radial direction R of the pneumatic vehicle tire, namely the first, the second and the third groove section having the aforementioned properties.

[0066] In one embodiment of the pneumatic vehicle tire according to the invention, the at least one circumferential groove extending in the circumferential direction of the pneumatic vehicle tire and designed to a tread depth PT has the same cross-section perpendicular to the circumferential direction over the entire circumference of the pneumatic vehicle tire. This cross-section is composed of at least two groove sections adjoining one another in the radial direction R of the pneumatic vehicle tire: the first groove section and the second inner groove section. The second inner groove section then, preferably with the described properties, exhibits good lateral stability against groove breakage and good wet performance over the entire circumference of the tire.

[0067] In one embodiment of the pneumatic vehicle tire according to the invention, the cross section perpendicular to the circumferential direction of the at least one circumferential groove of the pneumatic vehicle tire, which is composed at least over at least a partial section of the circumference of the pneumatic vehicle tire perpendicular to the circumferential direction of the at least two groove sections adjoining one another in the radial direction R of the pneumatic vehicle tire, the first groove section and the second inner groove section, has the same position in the axial direction of the pneumatic vehicle tire over the partial section of the circumference.

[0068] In one embodiment of the pneumatic vehicle tire according to the invention, the cross-section perpendicular to the circumferential direction of the at least one circumferential groove of the pneumatic vehicle tire, which is composed of the at least two groove sections adjoining one another in the radial direction R of the pneumatic vehicle tire, the first groove section and the second inner groove section, at least over at least a partial section of the circumference of the pneumatic vehicle tire perpendicular to the circumferential direction, changes its axial position over the circumference of the pneumatic vehicle tire. The axial position of the cross-section over the circumference of the pneumatic vehicle tire can follow a wavy line or a zigzag line. One embodiment of the pneumatic vehicle tire according to the invention can also have circumferential grooves in which the position of the cross-section in the axial direction remains the same on the one hand and changes on the other hand over different partial sections of the circumference of the pneumatic vehicle tire.Likewise, the position of the cross-section in the axial direction can change differently in different sections of the circumference of the pneumatic vehicle tire, e.g. in that the axial position of the cross-section over the circumference of the pneumatic vehicle tire follows a wavy line on the one hand and a zigzag line on the other.

[0069] A further embodiment of the pneumatic vehicle tire according to the invention has at least one circumferential groove which runs around the circumference of the pneumatic vehicle tire in the circumferential direction of the pneumatic vehicle tire and has a tread depth PT, which in at least one partial section of the circumference of the pneumatic vehicle tire is composed, in cross-section perpendicular to the circumferential direction, of the at least two groove sections which adjoin one another in the radial direction R of the pneumatic vehicle tire, the first groove section and the second inner groove section of the pneumatic vehicle tire, and in at least one partial section of the circumference of the pneumatic vehicle tire has a U-profile as a cross-section perpendicular to the circumferential direction. The U-profile is preferably designed asymmetrically, e.g. with a cross-section which is known from DE 10 2005 042 903 A1.Preferably, in the at least one circumferential groove, sections with a cross-section perpendicular to the circumferential direction, which is composed of the three groove sections adjoining one another in the radial direction R of the pneumatic vehicle tire, alternate with sections which have a U-profile as a cross-section perpendicular to the circumferential direction. Preferably, both sections have the same length in the circumferential direction. Between the two sections with the different cross-sections perpendicular to the circumferential direction, there are preferably transition regions over a distance of the circumference which is significantly smaller than the length of the sections in the circumferential direction. In this region, the structure of the cross-section changes from one form to the other.

[0070] In the design with an asymmetrical U-profile, the changing cross-section of the circumferential grooves creates areas around the circumference that combine good wet performance with low rolling resistance and a reduced risk of groove breakage thanks to at least two different groove cuts, and areas where wet performance is particularly good thanks to the open profile and lateral stiffness thanks to an asymmetrical U-profile. In wet conditions, water can flow from the asymmetrical U-profile into the second inner groove section of the multi-section cross-sectional area of ​​the other section, further reducing the risk of aquaplaning with this design.

[0071] In a particularly preferred embodiment of the pneumatic vehicle tire according to the invention, both circumferential grooves of the pneumatic vehicle tire, which are located on the outside in the tire profile in the axial direction A, have the two cross-sectional shapes alternating over the entire circumference. Preferably, the subsections of both circumferential grooves are arranged relative to one another such that, if in a subsection of the circumference one of the two circumferential grooves has the at least two-part cross-sectional area perpendicular to the circumferential direction, the other circumferential groove has a U-shaped cross-section perpendicular to the circumferential direction. As a result, wet performance, such as aquaplaning capability, optimal rolling resistance, and optimal transverse rigidity of the profile are evenly distributed over the circumference.As the tread of the pneumatic vehicle tire wears away, the circumferential sections with a cross-section featuring at least two groove sections also contribute more to aquaplaning behavior through the second inner groove section, thus compensating for the fact that other circumferential sections can absorb less water from the road surface as the groove depth decreases. Therefore, the profile change across the circumference, particularly in combination with the different profile of both outer grooves upon contact with the road surface, ensures that a pneumatic vehicle tire according to the invention exhibits good aquaplaning behavior over a long service life.

[0072] In addition, in each embodiment of the pneumatic vehicle tires according to the invention, a radially outwardly facing structure can be arranged in the second inner groove section in the bottom region of the circumferential groove, by means of which the penetration of small foreign bodies into the circumferential groove is made difficult or prevented.

[0073] In a preferred embodiment of the pneumatic vehicle tire according to the invention, the average width of the first groove section in the axial direction A of the pneumatic vehicle tire is 0.7 mm to 2.5 mm, preferably 0.9 to 2.0 mm, and particularly preferably 1.0 to 1.5 mm, with a tread elasticity with a modulus of elasticity at 60°C of 6.0 MPa to 7.0 MPa. Preferably, the width of the first groove section in the axial direction A is constant in the radial direction R.

[0074] In another preferred embodiment of the pneumatic vehicle tire according to the invention, the average width of the first groove section in the axial direction A of the pneumatic vehicle tire is 0.55 mm to 2 mm, preferably 0.8 to 1.5 mm, and particularly preferably 0.9 to 1.2 mm, with an elasticity of the tread having a modulus of elasticity at 60°C of 7.0 MPa to 8.0 MPa. Preferably, the width of the first groove section in the axial direction A is constant in the radial direction R. Brief description of the drawings

[0075] The invention will be explained in more detail using several exemplary embodiments. They show: Fig. 1: Cross section of a circumferential groove according to the prior art with three groove sections Fig. 2: First embodiment of a circumferential groove according to the invention with three groove sections Fig. 3: Second embodiment of a circumferential groove according to the invention with three groove sections Fig. 4: Third embodiment of a circumferential groove according to the invention with three groove sections Fig. 5: Fourth embodiment of a circumferential groove according to the invention with three groove sections Fig. 6: Fifth embodiment of a circumferential groove according to the invention with two groove sections Fig. 7: Tread of a pneumatic vehicle tire according to the invention with two outer grooves which have three groove sections in the radial direction, in which the inner groove section is asymmetrical in the axial direction Fig.8: Tread of a pneumatic vehicle tire according to the invention with two outer grooves which have an asymmetrical U-profile and three groove sections in the radial direction alternating over the circumference, the inner groove section of which is asymmetrical in the axial direction Fig. 9: Asymmetrical U-profile of a circumferential groove Fig. 10: Sixth embodiment of a circumferential groove according to the invention with three groove sections and a structure in the inner groove section which makes it difficult or impossible for small foreign bodies to penetrate into the groove. Detailed description of the invention

[0076] Fig. 2shows a circumferential groove 1 of a first embodiment of a pneumatic vehicle tire according to the invention. Shown is the cross section of the circumferential groove 1 perpendicular to the circumferential direction of the pneumatic vehicle tire in the tread 2 of the pneumatic vehicle tire. Here, the circumferential groove 1 is divided into three groove sections, a first groove section 4, a second inner groove section 5 and an outer third groove section 3. These groove sections are arranged in a radial direction R of the pneumatic vehicle tire. Here, both the first groove section 4 and the third groove section 3 are symmetrical to the radial direction R (shown by the directional arrow R in the Figure 2 ). The third groove section 3 widens outwards towards the surface of the tread 2. The cross section of the outer third groove section 3 of the Figure 2The circumferential groove 1 shown expands uniformly outwards in the radial direction R. Accordingly, the cross section of the third groove section 3 perpendicular to the circumferential direction has the shape of an isosceles and thus symmetrical trapezoid. In the new state of the pneumatic vehicle tire, the third groove section 3 on the surface of the tread 2 of the pneumatic vehicle tire at the

[0077] Embodiment a width GO in the axial direction A of 4 mm and a width GW min of 1.2 mm at its innermost point. This third groove section 3 is followed in the radial direction R by the first groove section 4. In the embodiment shown, this has a constant width in the axial direction A of 1.2 mm over its extent in the radial direction R. The first groove section 4 is thus narrower than the third groove section 3. The circumferential groove also has a second groove section 5. In this second groove section 5, the distance of the circumferential groove 1 to the center of the tire or the hub of the wheel that carries the pneumatic vehicle tire is at its smallest. Accordingly, the second inner groove section 5 has in its bottom region, the bottom region of the circumferential groove 6, a deepest point 7 of the circumferential groove, which is at the greatest distance from the surface of the tread 2 of the pneumatic vehicle tire.When the pneumatic vehicle tire is new, this distance is the tread depth PT of the pneumatic vehicle tire. The inner second groove section 5, adjacent to the first groove section 4, has the largest cross-sectional area of ​​the three groove sections of the circumferential groove. This cross-sectional area is asymmetrical to the radial direction. It extends on both sides of the radial direction and has a cornerless edge.

[0078] In the plane perpendicular to the circumferential direction of the pneumatic vehicle tire, the circumferential groove 1 has two sides. Side 8 of the circumferential groove faces the center of the pneumatic vehicle tire. Side 9 of the circumferential groove faces the outside of the pneumatic vehicle tire. Both sides of the circumferential groove 1 each have a curvature in the bottom region 6 of the circumferential groove 1, which is part of the second groove section 5. The radius of curvature of both sides is different. The radius of curvature R2 of the curvature of side 8 of the circumferential groove facing the center of the pneumatic vehicle tire is smaller than the radius of curvature R1 of side 9 of the circumferential groove facing the outside of the vehicle tire. The radius of curvature R2 of side 8 of the circumferential groove facing the center of the pneumatic vehicle tire is 2 mm in the exemplary embodiment. The radius of curvature R1 of side 9 of the circumferential groove facing the outside of the pneumatic vehicle tire is 4 mm.Thus, in the exemplary embodiment, the radius of curvature R2 of the side 8 facing the vehicle center is 50% smaller than the radius of curvature of the other side 9. In the exemplary embodiment, the cross-sectional area of ​​the second groove section 5 is not asymmetrical over its entire height H2 in the radial direction R. In the exemplary embodiment shown, the . Fig. 2the third groove section 3 has a height H3 of 2 mm in the radial direction R. The first groove section 4 has a height H1 of 3.5 mm in the radial direction R. The second groove section 5 has a height H2 of 6.5 mm in the radial direction R. Of this height, 73.8% of the height in the inner region of the second groove section 5 is asymmetrical. The asymmetrical region of the second groove section 5 therefore has a height of 4.8 mm in the radial direction R. The cross-sectional area of ​​the second groove section 5 between the axial direction R and the side 8 of the circumferential groove 1, which faces the center of the pneumatic vehicle tire, is, in the exemplary embodiment shown, approximately 1.1% smaller than the cross-sectional area of ​​the second groove section 5 between the radial direction R and the side 9 of the circumferential groove 1, which faces the outside of the pneumatic vehicle tire.Here, the percentage value is based on the area between the radial direction R and the side of the circumferential groove facing the outside of the pneumatic vehicle tire. If only the asymmetrical region of the cross-section of the second groove section 5 is considered, the area between the radial direction R and the side 8 of the circumferential groove 1 facing the center of the pneumatic vehicle tire is even approximately 1.4% smaller than the cross-sectional area of ​​the second groove section between the radial direction R and the side 9 of the circumferential groove 1 facing the outside of the pneumatic vehicle tire. The ratio of the areas between the individual sides 8, 9 of the circumferential groove 1 and the radial direction R, together with the geometry of the cross-sectional area, is essential for the optimal behavior of the circumferential groove 1, both with regard to wet performance and the transverse stiffness of the profile of the tread of the pneumatic vehicle tire.The area ratios between these surfaces, which are typically used, have already been described. The emphasis should be placed on the one shown in . Fig. 2 In the first exemplary embodiment of a circumferential groove 1 of a pneumatic vehicle tire according to the invention, the edge of the cross-sectional area of ​​the second groove section 5 has only one straight line on the side 8 facing the center of the vehicle tire, and no corners or other straight lines. Accordingly, the entire edge of the cross-sectional area of ​​the second groove section 5—apart from the straight line—has only curves. This leads to increased rigidity of the groove profile, particularly on the side of the circumferential groove 1 facing the outside of the vehicle tire, i.e., side 9.

[0079] In the first embodiment, the straight line on side 8, which points towards the centre of the vehicle tyre, has an angle of 8.1° with respect to the radial direction R. The distance of the straight line from the radial direction R decreases with increasing distance from the surface of the tread 2. Typically, in a pneumatic vehicle tyre according to the invention which has a straight line on side 8, which points towards the centre of the vehicle tyre, the angle with respect to the radial direction R is 0° to 15°, preferably 4° to 11° and particularly preferably 6° to 9°.

[0080] On both sides 8, 9 of the second groove section 5, there is a point on the edge of the cross-section which has the greatest section to the axial direction R. The edge point with the maximum distance from the radial direction R, which is located on the side 8 of the circumferential groove 1 facing the center of the pneumatic vehicle tire, has a distance from the radial direction R of 3.9 mm in the axial direction A. This point of maximum distance is also at a distance in the radial direction R of 4 mm from the deepest point 7 of the second groove section 5. The point on the edge of the cross-sectional area of ​​the second groove section 5, which is located on the side 9 of the circumferential groove 1 facing the outside of the pneumatic vehicle tire, has a distance of 4.6 mm from the radial direction R. Furthermore, this point has a distance in the radial direction R of 3.8 mm from the deepest point 7 of the circumferential groove 1.The two points of maximum spacing on both sides 8, 9 of the circumferential groove also define a maximum width GWmax of the cross-sectional area of ​​the third groove section 5. In the exemplary embodiment shown, the maximum width GWmax of the second groove section 5 is 8.5 mm. Typically, in a pneumatic vehicle tire according to the invention, the maximum width GWmax of the second groove section 5 is 4 mm to 10 mm, preferably 6 mm to 9 mm, and particularly preferably 7 mm to 8 mm. The two points of maximum spacing GWmax of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction were selected such that the circumferential groove 1 has both very good wet conditions properties and high transverse rigidity of the two sides 8, 9 of the circumferential groove, thereby preventing groove breakage in the circumferential groove.Overall, the cross-sectional profile of the second groove section 5 of the circumferential grooves 1 of the inventive pneumatic vehicle tire is selected such that a circumferential groove 1, due to the cross-sectional area of ​​the second groove section 5, exhibits very good wet properties, e.g., with regard to aquaplaning, and good resistance to groove breakage. It is precisely this compromise of properties that distinguishes the invention.

[0081] A ratio that describes this property very well is the ratio of the maximum width GWmax of the cross-sectional area of ​​the second groove section 5 to the maximum height H2 of the cross-sectional area in the direction of the radial direction R. In the embodiment that in the Fig. 2As shown, the maximum width GWmax perpendicular to the radial direction R of the cross-sectional area is 30.7% greater than the maximum height H2 of the cross-sectional area in the direction of the radial direction R. Furthermore, in the exemplary embodiment, the distance to the radial direction R of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire is greater than the distance of the edge point on the other side 8 to the radial direction R, which has the greatest distance to the radial direction R. In this case, the distance of the edge point on the side 9 facing the outside of the pneumatic vehicle tire is 17.9% greater in the exemplary embodiment than the corresponding distance of the edge point to the radial direction R, which has the maximum distance on the side 8 facing the center of the pneumatic vehicle tire.Typically, in a pneumatic vehicle tire according to the invention, the distance of the edge point with maximum distance from the radial direction on the side 9 facing the outside of the pneumatic vehicle tire is 5% to 35% greater, preferably 8% to 25% greater and particularly preferably 12% to 18% greater than on the side 8 facing the center of the pneumatic vehicle tire.

[0082] The distance from the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance from the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove is 3.8 mm in the radial direction, with a maximum height H2 of the cross-sectional area of ​​the second groove section of 6.5 mm. Accordingly, the distance from this edge point to the deepest point of the circumferential groove in the radial direction R is 58.4% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5.Typically, the distance of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove in the radial direction R is between 30% and 80% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5, preferably between 50% and 75% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 and particularly preferably between 55% and 65% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5. By positioning the outermost edge point of the side 9 of the circumferential groove facing the outside of the pneumatic vehicle tire, the transverse stiffness of this side of the profile of the tread 2 is increased.

[0083] The distance of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance from the radial direction R on the side 8 that is free to the center of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove 1 is 4 mm in the radial direction R in the exemplary embodiment. Accordingly, the distance of this edge point to the deepest point 7 of the circumferential groove 1 is 61.5% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 in the radial direction R.

[0084] Typically, the distance of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 8 facing the center of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove in the radial direction R is between 50% and 80% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5, preferably between 55% and 75% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 and particularly preferably between 60% and 70% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5. By positioning the outermost edge point of the side 8 of the circumferential groove facing the center of the pneumatic vehicle tire, the water absorption capacity of the second groove section 5 is increased, thereby improving the contribution of the circumferential groove 1 to the good wet performance of the pneumatic vehicle tire according to the invention.

[0085] The bottom region 6 of the circumferential groove 1 typically has, as shown in the exemplary embodiment, the two radii of curvature R1 and R2. These are the smallest radii of curvature of both sides 8 and 9 of the circumferential groove 1 in the bottom region 6 of the circumferential groove 1. Here, the smallest radius of curvature R1 of the side 9 of the circumferential groove 2 in the bottom region 6, which faces the outside of the pneumatic vehicle tire, is greater than the smallest radius of curvature R2 of the side 8 in the bottom region 6, which faces the center of the pneumatic vehicle tire. In the exemplary embodiment of the Fig. 2 The radius of curvature R1 is 4 mm and the radius of curvature R2 is 2 mm. Accordingly, the radius of curvature R2 located at the bottom of side 8 of the circumferential groove 2 facing the center of the pneumatic vehicle tire is 50% smaller than the radius of curvature R1 of the other side 9.

[0086] Typically, the smallest radius of curvature R1 of side 9 in the base region 6 of the circumferential groove 1 in a pneumatic vehicle tire according to the invention has a value between 1.5 mm and 5.0 mm, preferably between 2.0 mm and 4.2 mm, and particularly preferably between 3.5 and 4.0 mm. The smallest radius of curvature R2 of side 8 in the base region 6 of the circumferential groove 1 in a pneumatic vehicle tire according to the invention typically has a value between 0.7 mm and 2.5 mm, preferably between 1.0 mm and 2.2 mm, and particularly preferably between 1.5 and 2.0 mm.

[0087] In the embodiment shown, the Fig. 2the cross-section of the outer third groove section 3 of the circumferential groove 1 shown widens uniformly outwards in the axial direction A. Therefore, both sides of the third groove section 3 form straight lines which have an angle to the radial direction R which, in the exemplary embodiment, is 35°. The width GO of the first groove section 3 tapers from the surface of the tread 2 of the pneumatic vehicle tire in the new state of 4 mm to a width in the axial direction of 1.2 mm (GWmin). The material of the tread 2 of the pneumatic vehicle tire, in which the circumferential groove shown is arranged, is usually a rubber mixture. Typically, the material has a modulus of elasticity in the range of 11 MaPa at 60°C, preferably a modulus of elasticity in the range of 4.0 to 9.0 MaPa and particularly preferably a modulus of elasticity in the range of 5.5 to 8.0 MaPa.In the illustrated embodiment, a modulus of elasticity of 6.5 MaPa is used. The modulus of elasticity is determined according to DIN EN 527. Furthermore, the tread of a pneumatic vehicle tire according to the invention has a loss factor tan δ, which is typically in the range of 0.03 to 0.25 at 60°C, preferably in the range of 0.05 to 0.2 at 60°C, and particularly preferably in the range of 0.75 to 0.1 at 60°C. In the illustrated embodiment, the loss factor tan δ is 0.085. The loss factor of the material of tread 2 is determined according to DIN 52 513 and describes the hysteresis behavior of the viscoelastic material of tread 2.

[0088] Fig. 3 shows a circumferential groove 1 of a second embodiment of a pneumatic vehicle tire according to the invention. The same and corresponding components are identified by the same reference numerals as in the Figure 2 shown first embodiment.

[0089] Shown is as in Fig. 2 the cross-section of the circumferential groove 1 perpendicular to the circumferential direction of the pneumatic vehicle tire in the tread 2 of the pneumatic vehicle tire. Here, the circumferential groove 1 is divided into three groove sections: a first groove section 4, a second inner groove section 5, and an outer third groove section 3. These groove sections are arranged in a radial direction R of the pneumatic vehicle tire.

[0090] The first groove section 4 and the third groove section 3 are unchanged from the first embodiment. Therefore, both the first groove section 4 and the third groove section 3 are symmetrical to the radial direction R (shown by the directional arrow R in the Figure 3 ). Further details on these groove sections can be found in the Fig. 2 shown first embodiment.

[0091] Furthermore, the Fig. 3The circumferential groove 1 shown has a second groove section 5 which is designed differently than the one shown in Fig. 2shown first embodiment. In this second groove section 5, too, the distance of the circumferential groove 1 to the center of the tire or the hub of the wheel carrying the pneumatic vehicle tire 1 is the smallest. Accordingly, the second inner groove section 5 has, in its bottom region, the bottom region 6 of the circumferential groove 1, a deepest point 7 of the circumferential groove, which is at the greatest distance from the surface of the tread of the pneumatic vehicle tire. When the pneumatic vehicle tire is new, this distance is the tread depth PT of the pneumatic vehicle tire. The second inner groove section 5 adjoining the first groove section has the largest cross-sectional area of ​​the three groove sections of the circumferential groove. This cross-sectional area is asymmetrical to the radial direction. It extends on both sides of the radial direction and has an edge without corners.

[0092] In the plane perpendicular to the circumferential direction of the pneumatic vehicle tire, the circumferential groove 1 has two sides. Side 8 of the circumferential groove faces the center of the pneumatic vehicle tire. Side 9 of the circumferential groove faces the outside of the pneumatic vehicle tire. Both sides of the circumferential groove face Fig. 2In the first exemplary embodiment shown, the bottom region 6 of the circumferential groove 1, which is part of the second groove section 5, each has a curvature. The radius of curvature of both sides is different. The radius of curvature of the curvature R2 of the side 8 of the circumferential groove facing the center of the pneumatic vehicle tire is smaller than the radius of curvature R1 of the side 9 of the circumferential groove facing the outside of the vehicle tire. The radius of curvature R2 of the side 8 of the circumferential groove facing the center of the pneumatic vehicle tire is 2 mm in the exemplary embodiment. The radius of curvature R1 of the side 9 of the circumferential groove facing the outside of the pneumatic vehicle tire is 4 mm. Thus, in the exemplary embodiment, the radius of curvature R2 of the side 8 facing the center of the vehicle is 50% smaller than the radius of curvature R1 of the other side 9.In the embodiment, the cross-sectional area of ​​the second groove portion 5 is not asymmetrical over its entire height in the radial direction R.

[0093] The second groove section 5 has a height H2 of 6.5 mm in the radial direction. Of this height, 78.7% of the height in the inner region of the third groove section 5 is asymmetric. The asymmetric region of the third groove section 5 therefore has a height of 5.12 mm in the radial direction R.

[0094] Compared to the Fig. 2 In the first embodiment of a circumferential groove 1 of a pneumatic vehicle tire according to the invention, the edge of the cross-sectional area of ​​the third groove section 5 in the Fig. 3The second embodiment shown has a straight line on both sides 8 and 9 and no corners or other straight lines. Accordingly, the entire edge of the cross-sectional area of ​​the third groove section 5—apart from the two straight lines—has curvatures.

[0095] The straight line 15 on side 9 of the circumferential groove 1, which faces the outside of the vehicle tire, is designed in such a way that it contributes to increased rigidity of the groove profile, particularly on side 9.

[0096] The straight line 15 is inclined by 33.3° relative to the radial direction R and runs towards the radial direction R with increasing depth of the circumferential groove. It extends in the radial direction R over 1.95 mm, which corresponds to 30.0% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5.

[0097] On both sides 8, 9 of the second groove section 5 there is a point on the edge of the cross-section which has the greatest section to the axial direction R. The edge point with the maximum distance from the radial direction R, which is located on the side 8 of the circumferential groove 1 which faces the center of the pneumatic vehicle tire, has a distance from the radial direction R of 4 mm in the axial direction A. The point on the edge of the cross-sectional area of ​​the second groove section 5, which lies on the side 9 of the circumferential groove 1 which faces the outside of the pneumatic vehicle tire, has a distance of 4.27 mm from the radial direction R. The two points of the maximum distance on both sides 8, 9 of the circumferential groove also define a maximum width GWmax of the cross-sectional area of ​​the second groove section 5 in the axial direction A. In the exemplary embodiment shown, the maximum width GWmax of the second groove section 5 is 8.27 mm.

[0098] The straight line 15 of side 9 of the circumferential groove 1, which points towards the outside of the pneumatic vehicle tire, begins on side 9, viewed from the surface of the tread 2 of the pneumatic vehicle tire, almost below the point on side 9 which has the greatest section to the axial direction R. Opposite this point, the straight line is oriented inwards towards the center of the tire and reduces the width of the second groove section 5 due to its inclination to the radial direction R. Opposite the deepest point 7 of the circumferential groove, the distance of the straight line in the radial direction R at its innermost point is 1.50 mm, which corresponds to 23.1% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 in the radial direction R, and at its outermost point is 3.45 mm, which corresponds to 53.1% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 in the radial direction R.The straight line 15 is followed inwards by a curved transition area, followed by the area of ​​the floor area 6 with the radius of curvature R1.

[0099] The two points of maximum distance GWmax of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction and the straight line 15 on side 9 of the circumferential groove 1 were generally selected such that the circumferential groove 1 has both very good wet properties and high transverse rigidity of the two sides 8, 9 of the circumferential groove, thereby preventing groove breakage. Overall, the cross-sectional profile of the third groove section 5 of the circumferential grooves 1 of the inventive pneumatic vehicle tire is generally selected such that a circumferential groove 1, due to the cross-sectional area of ​​the second groove section 5, has very good wet properties, e.g., with regard to aquaplaning, and good resistance to groove breakage. It is precisely this compromise of properties that distinguishes the invention.

[0100] A ratio that describes this property very well is the ratio of the maximum width GWmax of the cross-sectional area of ​​the second groove section 5 to the maximum height H2 of the cross-sectional area in the direction of the radial direction R. In the embodiment that in the Fig. 3As shown, the maximum width GWmax perpendicular to the radial direction R of the cross-sectional area is 27.2% greater than the maximum height H2 of the cross-sectional area in the direction of the radial direction R. Furthermore, in the exemplary embodiment, the distance to the radial direction R of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire is greater than the distance of the edge point on the other side 8 to the radial direction R, which has the greatest distance to the radial direction R. In this case, the distance of the edge point on the side 9 facing the outside of the pneumatic vehicle tire is 17.9% greater in the exemplary embodiment than the corresponding distance of the edge point to the radial direction R, which has the maximum distance on the side 8 facing the center of the pneumatic vehicle tire.

[0101] The distance of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove is 3.8 mm in the radial direction R with a maximum height H2 of the cross-sectional area of ​​the second groove section of 6.5 mm in the radial direction R. Accordingly, the distance of this edge point to the deepest point of the circumferential groove in the radial direction R is 57% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5. By positioning the outermost edge point of the side 9 of the circumferential groove facing the outside of the pneumatic vehicle tire, the transverse rigidity of this side of the profile of the tread 2 is increased.

[0102] The distance of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 8 that is free to the center of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove 1 is 4 mm in the radial direction R in the exemplary embodiment. Accordingly, the distance of this edge point to the deepest point of the circumferential groove 6 is 61.5% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 in the direction of the radial direction R. By positioning the outermost edge point of side 8 of the circumferential groove, which faces the center of the pneumatic vehicle tire, this increases the water absorption capacity of the second groove section 5, thereby improving the contribution of the circumferential groove 1 to the good wet performance of the pneumatic vehicle tire according to the invention.

[0103] The base region 6 of the circumferential groove 1 has, in the exemplary embodiment, the two already mentioned radii of curvature R1 and R2. These are the main radii of curvature of the two sides 8 and 9 in the base region of the circumferential groove 1, i.e. the radii of curvature by which the contour of both sides in the base region is predetermined over the largest side length. Here, the main radius of curvature R1 of the side 9 of the circumferential groove 1, which faces the outside of the pneumatic vehicle tire, in embodiments of the pneumatic vehicle tire according to the invention such as the one in Figure 3shown is larger than the principal radius of curvature R2 of the side 8 facing the center of the pneumatic vehicle tire. In the exemplary embodiment, the principal radius of curvature R1 is 4 mm and the principal radius of curvature R2 is 2 mm. Accordingly, the principal radius of curvature R2 located in the bottom region of the side 8 of the circumferential groove 1 facing the center of the pneumatic vehicle tire is 50% smaller than the principal radius of curvature R1 of the other side. Typically, in pneumatic vehicle tires according to the invention, the main radius of curvature R2 located in the bottom region of the side 8 of the circumferential groove 1 facing the center of the pneumatic vehicle tire is 20% smaller than the main radius of curvature R1 in the bottom region of the other side, preferably 35% smaller than the main radius of curvature R1 in the bottom region of the other side, and particularly preferably 50% smaller than the main radius of curvature R1 in the bottom region of the other side.

[0104] The material of the tread 2 of the pneumatic vehicle tire according to the invention with the Fig. 3 The second embodiment of a circumferential groove 1 shown corresponds to that of the Fig. 2 shown first embodiment of a circumferential groove 1.

[0105] Fig. 4 shows a circumferential groove 1 of a third embodiment of a pneumatic vehicle tire according to the invention. The same and corresponding components are identified by the same reference numerals as in the Figure 2 shown first embodiment.

[0106] Shown is as in Fig. 2the cross-section of the circumferential groove 1 perpendicular to the circumferential direction of the pneumatic vehicle tire in the tread 2 of the pneumatic vehicle tire. The circumferential groove 1 is divided into three groove sections: a first groove section 4, a second inner groove section 5, and an outer third groove section 3. These groove sections are arranged in a radial direction R of the pneumatic vehicle tire.

[0107] The first groove section 4 and the third groove section 3 are unchanged from the first and second embodiments. Therefore, both the first groove section 4 and the third groove section 3 are symmetrical to the radial direction R (shown by the directional arrow R in the Figure 4 ). Further details on these groove sections can be found in Fig. 2 shown first embodiment.

[0108] Furthermore, the Fig. 4The circumferential groove 1 shown has a second groove section 5 which is designed differently than the one shown in Fig. 2shown first embodiment. In this second groove section 5, too, the distance of the circumferential groove 2 to the center of the tire or the hub of the wheel carrying the pneumatic vehicle tire 1 is the smallest. Accordingly, the second inner groove section 5 has, in its bottom region, the bottom region 6 of the circumferential groove 1, a deepest point 7 of the circumferential groove, which is at the greatest distance from the surface of the tread of the pneumatic vehicle tire. When the pneumatic vehicle tire is new, this distance is the tread depth PT of the pneumatic vehicle tire. The second inner groove section 5 adjoining the first groove section has the largest cross-sectional area of ​​the three groove sections of the circumferential groove. This cross-sectional area is asymmetrical to the radial direction. It extends on both sides of the radial direction and has an edge without corners.

[0109] In the plane perpendicular to the circumferential direction of the pneumatic vehicle tire, the circumferential groove 1 has two sides. Side 8 of the circumferential groove faces the center of the pneumatic vehicle tire. Side 9 of the circumferential groove faces the outside of the pneumatic vehicle tire. Both sides of the circumferential groove face Fig. 2In the first exemplary embodiment shown, the bottom region 6 of the circumferential groove 1, which is part of the second groove section 5, each has a curvature. The radius of curvature of both sides is different. The radius of curvature of the curvature R2 of the side 8 of the circumferential groove facing the center of the pneumatic vehicle tire is smaller than the radius of curvature R1 of the side 9 of the circumferential groove facing the outside of the vehicle tire. The radius of curvature R2 of the side 8 of the circumferential groove facing the center of the pneumatic vehicle tire is 2 mm in the exemplary embodiment. The radius of curvature R1 of the side 9 of the circumferential groove facing the outside of the pneumatic vehicle tire is 4 mm. Thus, in the exemplary embodiment, the radius of curvature R2 of the side 8 facing the center of the vehicle is 50% smaller than the radius of curvature R1 of the other side 9.

[0110] The second groove section 5 has a height H2 of 6.5 mm in the radial direction. Of this height, 78.7% of the height in the inner region of the second groove section 5 is asymmetric. The asymmetric region of the third groove section 5 therefore has a height of 5.12 mm in the radial direction R.

[0111] Compared to the Fig. 2 In the first embodiment of a circumferential groove 1 of a pneumatic vehicle tire according to the invention, the edge of the cross-sectional area of ​​the second groove section 5 in the embodiment shown in Fig. 4 The third embodiment shown has a straight line on both sides 8 and 9 and no corners or other straight lines. Accordingly, the entire edge of the cross-sectional area of ​​the second groove section 5—apart from the two straight lines—has curvatures.

[0112] The straight line 16 on side 9 of the circumferential groove 1, which faces the outside of the pneumatic vehicle tire, is designed in such a way that it contributes to increased rigidity of the groove profile, in particular on side 9.

[0113] The straight line 16 is inclined by 13.9° relative to the radial direction R and, with increasing depth of the circumferential groove, tapers toward the radial direction R. It extends in the radial direction R over 0.93 mm, which corresponds to 14.3% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5. The straight line 16 on side 9 of the circumferential groove, which faces the outside of the pneumatic vehicle tire, in this third embodiment is shorter than the corresponding straight line 15 of the second embodiment and has a smaller inclination relative to the radial direction.

[0114] Typically, in a pneumatic vehicle tire according to the invention, a straight line which belongs to the edge of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction, on the side 9 of the circumferential groove which points towards the outside of the pneumatic vehicle tire, extends over at most 45% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5, preferably over at most 20% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 and particularly preferably over at most 5% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5. Such a straight line typically has an inclination with respect to the radial direction R of at least 5°, preferably at least 20° and particularly preferably at least 25°. A longer straight line on the side 9 of the circumferential groove 1 has a greater inclination with respect to the radial direction R.These properties increase the transverse stiffness of the tread pattern, particularly in its shoulder area.

[0115] On both sides 8, 9 of the second groove section 5 there is a point on the edge of the cross-section which has the greatest section to the axial direction R. The edge point with the maximum distance from the radial direction R, which is located on the side 8 of the circumferential groove 1 which faces the center of the pneumatic vehicle tire, has a distance from the radial direction R of 4 mm in the axial direction A. The point on the edge of the cross-sectional area of ​​the second groove section 5, which lies on the side 9 of the circumferential groove 1 which faces the outside of the pneumatic vehicle tire, has a distance of 4.27 mm from the radial direction R. The two points of the maximum distance on both sides 8, 9 of the circumferential groove also define a maximum width GWmax of the cross-sectional area of ​​the second groove section 5 in the axial direction A. In the exemplary embodiment shown, the maximum width GWmax of the second groove section 5 is 8.27 mm.

[0116] The straight line 16 of side 9 of the circumferential groove 1, which points towards the outside of the pneumatic vehicle tire, begins on side 9, viewed from the surface of the tread 2 of the pneumatic vehicle tire, almost below the point on side 9 which has the greatest section to the axial direction R. Opposite this point, the straight line is oriented inwards towards the center of the tire and reduces the width of the second groove section 5 through its inclination to the radial direction R. Opposite the deepest point 7 of the circumferential groove, the distance of the straight line in the radial direction R at its innermost point is 2.82 mm, which corresponds to 43.4% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5, and at its outermost point is 3.75 mm, which corresponds to 57.7% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5. The area of ​​the base area 6 with the radius of curvature R1 adjoins the straight line 16 inwards after a curved transition area.

[0117] The two points of maximum distance GWmax of the cross-sectional area of ​​the third groove section 5 perpendicular to the circumferential direction and the straight line 16 on side 9 of the circumferential groove 1 were selected such that the circumferential groove 1 has both very good wet properties and high transverse rigidity of the two sides 8, 9 of the circumferential groove, thereby preventing groove breakage. Overall, the cross-sectional profile of the second groove section 5 of the circumferential grooves 1 of the inventive pneumatic vehicle tire is selected such that a circumferential groove 1, due to the cross-sectional area of ​​the third groove section 5, has very good wet properties, e.g., with regard to aquaplaning, and good resistance to groove breakage. It is precisely this compromise of properties that distinguishes the invention.

[0118] A ratio that describes this property very well is the ratio of the maximum width GWmax of the cross-sectional area of ​​the second groove section 5 to the maximum height H2 of the cross-sectional area in the direction of the radial direction R. In the embodiment that in the Fig. 4As shown, the maximum width GWmax perpendicular to the radial direction R of the cross-sectional area is 27.2% greater than the maximum height H2 of the cross-sectional area in the direction of the radial direction R. Furthermore, in the exemplary embodiment, the distance to the radial direction R of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire is greater than the distance of the edge point on the other side 8 to the radial direction R, which has the greatest distance to the radial direction R. In this case, the distance of the edge point on the side 9 facing the outside of the pneumatic vehicle tire is 17.9% greater in the exemplary embodiment than the corresponding distance of the edge point to the radial direction R, which has the maximum distance on the side 8 facing the center of the pneumatic vehicle tire.

[0119] The distance from the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove is 3.8 mm with a maximum height H2 of the cross-sectional area of ​​the third groove section of 6.5 mm. Accordingly, the distance from this edge point to the deepest point of the circumferential groove in the radial direction R is 58.4% of the maximum height of the cross-sectional area of ​​the third groove section 5. This positioning of the outermost edge point of side 9 of the circumferential groove facing the outside of the pneumatic vehicle tire increases the transverse rigidity of this side of the profile of the tread 2.

[0120] The distance of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 8 that is free to the center of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove 1 is 4 mm in the exemplary embodiment. Accordingly, the distance of this edge point to the deepest point of the circumferential groove 6 is 61.5% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 in the direction of the radial direction R. By positioning the outermost edge point of side 8 of the circumferential groove, which faces the center of the pneumatic vehicle tire, this increases the water absorption capacity of the second groove section 5, thereby improving the contribution of the circumferential groove 1 to the good wet performance of the pneumatic vehicle tire according to the invention.

[0121] The bottom region 6 of the circumferential groove 1 typically has, as shown in the exemplary embodiment, two radii of curvature R1 and R2. These are the smallest radii of curvature of both sides 8 and 9 of the circumferential groove 1 in the bottom region 6 of the circumferential groove 1. Here, the smallest radius of curvature R1 of the side 9 of the circumferential groove 1 in the bottom region 6, which faces the outside of the pneumatic vehicle tire, is larger than the smallest radius of curvature R2 of the side 8 in the bottom region 6, which faces the center of the pneumatic vehicle tire. In the exemplary embodiment, the radius of curvature R1 is 4 mm and the radius of curvature R2 is 2 mm. Accordingly, the radius of curvature R2 located at the bottom portion 6 of the side 8 of the circumferential groove 1 facing the center of the pneumatic vehicle tire is 50% smaller than the radius of curvature R1 of the other side 9.

[0122] The material of the tread 2 of the pneumatic vehicle tire according to the invention with the Fig. 4The third embodiment of a circumferential groove 1 shown corresponds to that of the Fig. 2 shown first embodiment of a circumferential groove 1.

[0123] Fig. 5 shows a circumferential groove 1 of a fourth particularly preferred embodiment of a pneumatic vehicle tire according to the invention. The same and corresponding components are identified by the same reference numerals as in the Figure 2 shown first embodiment.

[0124] Shown is as in Fig. 2 the cross-section of the circumferential groove 1 perpendicular to the circumferential direction of the pneumatic vehicle tire in the tread 2 of the pneumatic vehicle tire. Here, the circumferential groove 1 is divided into three groove sections: a first groove section 4, a second inner groove section 5, and an outer third groove section 3. These groove sections are arranged in a radial direction R of the pneumatic vehicle tire.

[0125] The first groove section 4 and the third groove section 3 are unchanged from the first embodiment. Therefore, both the first groove section 4 and the third groove section 3 are symmetrical to the radial direction R (shown by the directional arrow R in the Figure 5 ). Further details on these groove sections can be found in the Fig. 2 shown first embodiment.

[0126] Furthermore, the Figure 5The circumferential groove 1 of the fourth embodiment shown has a second groove section 5. In this second groove section 5, the distance of the circumferential groove 1 to the center of the tire or the hub of the wheel carrying the pneumatic vehicle tire is the smallest. Accordingly, the second inner groove section 5 has, in its bottom region, the bottom region 6 of the circumferential groove 1, a deepest point 7 of the circumferential groove, which is at the greatest distance from the surface of the tread 2 of the pneumatic vehicle tire. When the pneumatic vehicle tire is new, this distance is the tread depth PT of the pneumatic vehicle tire. The inner second groove section 5 adjoining the first groove section also has the largest cross-sectional area of ​​the three groove sections of the circumferential groove in the fourth embodiment. This cross-sectional area is asymmetrical to the radial direction. It extends on both sides of the radial direction and has an edge without corners.

[0127] Both sides of the Fig. 5The circumferential groove 1 shown, the side 8 facing the center of the pneumatic vehicle tire, and the side 9 facing the outside of the pneumatic vehicle tire, each have a curvature in the bottom region 6 of the circumferential groove 1, which is part of the second groove section 5. The radius of curvature of both sides is different. The radius of curvature R2 of the curvature of the side 8 of the circumferential groove facing the center of the pneumatic vehicle tire is smaller than the radius of curvature R1 of the side 9 of the circumferential groove facing the outside of the vehicle tire. The radius of curvature R2 of the side 8 of the circumferential groove facing the center of the pneumatic vehicle tire is 2 mm in the exemplary embodiment. The radius of curvature R1 of the side 9 of the circumferential groove facing the outside of the pneumatic vehicle tire is 4 mm. Thus, in the exemplary embodiment, the radius of curvature R2 of the side 8, which points towards the center of the vehicle, is 50% smaller than the radius of curvature of the other side 9.In the exemplary embodiment, the cross-sectional area of ​​the second groove section 5 is not asymmetrical over its entire height H2 in the radial direction R. The second groove section 5 has a height H2 of 6.5 mm in the radial direction in the direction R. Of this height, 76% of the height in the inner region of the second groove section 5 is asymmetrical. The asymmetric region of the second groove section 5 therefore has a height of 4.94 mm in the radial direction R. The cross-sectional area of ​​the second groove section 5 between the axial direction R and the side 8 of the circumferential groove 1, which faces the center of the pneumatic vehicle tire, is, in the exemplary embodiment shown, approximately 22.2% larger than the cross-sectional area of ​​the second groove section 5 between the radial direction R and the side 9 of the circumferential groove 1, which faces the outside of the pneumatic vehicle tire.Here, the percentage value is based on the area between the radial direction R and the side of the circumferential groove facing the outside of the pneumatic vehicle tire. If only the asymmetrical region of the cross-section of the second groove section 5 is considered, the area between the radial direction R and side 8 of the circumferential groove 1 facing the center of the pneumatic vehicle tire is even approximately 29.7% larger than the cross-sectional area of ​​the second groove section between the radial direction R and side 9 of the circumferential groove 1 facing the outside of the pneumatic vehicle tire. The ratio of the areas between the individual sides 8 and 9 of the circumferential groove 1 and the radial direction R, together with the geometry of the cross-sectional area, is essential for the optimal behavior of the circumferential groove 1, both with regard to wet performance and the transverse stiffness of the profile of the tread of the pneumatic vehicle tire.

[0128] Even with the Fig. 5In the fourth exemplary embodiment of a circumferential groove 1 of a pneumatic vehicle tire according to the invention, the edge of the cross-sectional area of ​​the second groove section 5 has only one straight line on side 8 facing the center of the vehicle tire, and no corners or other straight lines. Accordingly, the entire edge of the cross-sectional area of ​​the second groove section 5—apart from the straight line—has only curves. This leads to increased rigidity of the groove profile, particularly on the side of the circumferential groove 1 facing the outside of the vehicle tire, i.e., side 9.

[0129] In the first embodiment, the straight line on side 8, which points toward the center of the vehicle tire, has an angle of 8.4° relative to the radial direction R. The distance of the straight line from the radial direction R decreases with increasing distance from the surface of the tread 2.

[0130] On both sides 8, 9 of the second groove section 5, there is a point on the edge of the cross-section which has the greatest section to the axial direction R. The edge point with the maximum distance from the radial direction R, which is located on the side 8 of the circumferential groove 1 facing the center of the pneumatic vehicle tire, has a distance from the radial direction R of 3.45 mm in the axial direction A. This point of maximum distance is also at a distance in the radial direction R of 4.2 mm from the deepest point 7 of the second groove section 5. The point on the edge of the cross-sectional area of ​​the second groove section 5, which is located on the side 9 of the circumferential groove 1 facing the outside of the pneumatic vehicle tire, has a distance of 3.95 mm from the radial direction R. Furthermore, this point has a distance in the radial direction R of 4.0 mm from the deepest point 7 of the circumferential groove 1.The two points of maximum spacing on both sides 8, 9 of the circumferential groove also define a maximum width GWmax of the cross-sectional area of ​​the third groove section 5. In the exemplary embodiment shown, the maximum width GWmax of the second groove section 5 is 7.4 mm. The two points of maximum spacing GWmax of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction were selected such that the circumferential groove 1 has both very good wet properties and high transverse rigidity of the two sides 8 and 9 of the circumferential groove, thereby preventing groove breakage. Overall, the cross-sectional profile of the second groove section 5 of the circumferential grooves 1 of the inventive pneumatic vehicle tire is selected such that a circumferential groove 1, due to the cross-sectional area of ​​the second groove section 5, has very good wet properties, e.g., with regard to aquaplaning, and good resistance to groove breakage.A very good compromise of these properties is the one in . Figure 5 shown circumferential groove 1.

[0131] A ratio that describes this property very well is the ratio of the maximum width GWmax of the cross-sectional area of ​​the second groove section 5 to the maximum height H2 of the cross-sectional area in the direction of the radial direction R. In the fourth embodiment, that in the Fig. 5As shown, the maximum width GWmax perpendicular to the radial direction R of the cross-sectional area is 13.8% greater than the maximum height H2 of the cross-sectional area in the direction of the radial direction R. Furthermore, in the exemplary embodiment, the distance to the radial direction R of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire is greater than the distance of the edge point on the other side 8 to the radial direction R, which has the greatest distance to the radial direction R. In this case, the distance of the edge point on the side 9 facing the outside of the pneumatic vehicle tire is 16.7% greater in the exemplary embodiment than the corresponding distance of the edge point to the radial direction R, which has the maximum distance on the side 8 facing the center of the pneumatic vehicle tire.

[0132] The distance from the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 9 facing the outside of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove is 4.0 mm in the radial direction with a maximum height H2 of the cross-sectional area of ​​the second groove section of 6.5 mm. Accordingly, the distance from this edge point to the deepest point of the circumferential groove in the radial direction R is 61.5% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5. This positioning of the outermost edge point of side 9 of the circumferential groove facing the outside of the pneumatic vehicle tire increases the transverse rigidity of this side of the profile of the tread 2.

[0133] The distance of the edge point of the cross-sectional area of ​​the second groove section 5 perpendicular to the circumferential direction with the greatest distance to the radial direction R on the side 8 that is free to the center of the pneumatic vehicle tire to the deepest point 7 of the circumferential groove 1 is 4.2 mm in the radial direction R in the exemplary embodiment. Accordingly, the distance of this edge point to the deepest point 7 of the circumferential groove 1 is 64.6% of the maximum height H2 of the cross-sectional area of ​​the second groove section 5 in the direction of the radial direction R. By positioning the outermost edge point of side 8 of the circumferential groove, which faces the center of the pneumatic vehicle tire, this increases the water absorption capacity of the second groove section 5, thereby improving the contribution of the circumferential groove 1 to the good wet performance of the pneumatic vehicle tire according to the invention.

[0134] The bottom area 6 of the circumferential groove 1 has in the Figure 5shown embodiment, the two radii of curvature R1 and R2. These are in the bottom area 6 of the circumferential groove 1 respectively the smallest radii of curvature of both sides 8 and 9 of the circumferential groove 1. Here, the smallest radius of curvature R1 of the side 9 of the circumferential groove 2 in the bottom area 6, which faces the outside of the pneumatic vehicle tire, is larger than the smallest radius of curvature R2 of the side 8 in the bottom area 6, which faces the center of the pneumatic vehicle tire. In the embodiment of the Fig. 5 The radius of curvature R1 is 4 mm and the radius of curvature R2 is 2 mm. Accordingly, the radius of curvature R2 located at the bottom of side 8 of the circumferential groove 2 facing the center of the pneumatic vehicle tire is 50% smaller than the radius of curvature R1 of the other side 9.

[0135] Fig. 6shows a circumferential groove 1 of a fifth embodiment of a pneumatic vehicle tire according to the invention. The same and corresponding components are identified by the same reference numerals as in the Figure 5 shown fourth embodiment. Shown is as in Fig. 5 the cross-section of the circumferential groove 1 perpendicular to the circumferential direction of the pneumatic vehicle tire in the tread 2 of the pneumatic vehicle tire. However, in contrast to the previously shown embodiments, the circumferential groove 1 is divided into only two groove sections: a first outer groove section 4 and a second inner groove section 5. These groove sections are arranged in a radial direction R of the pneumatic vehicle tire.

[0136] The first groove section 4 is arranged symmetrically to the radial direction. The first outer groove section 4 ends at the surface of the tread 2 of the pneumatic vehicle tire. In the illustrated embodiment, it has a constant width GW min in the axial direction A, which amounts to 1.2 mm, across its extension in the radial direction R. The first radial groove section has a height H1 of 5.5 mm in the radial direction R.

[0137] In other such embodiments of the pneumatic vehicle tire according to the invention with circumferential grooves 1, which are composed only of the first outer groove section 4 and a second inner groove section 5, the height H1 of the first radial groove section in the direction of the radial direction R is typically 2 mm to 11 mm, preferably 4 mm to 9 mm and particularly preferably 5 mm to 7 mm.

[0138] The one in Figure 6The second inner groove section 5 adjoining the first groove section 4 in the fifth embodiment shown has a cross section in the axial direction A which is wider than this width GW min. The second inner groove section 5 is the one shown in Figure 6 showed fifth embodiment compared to that of the Figure 5 fourth embodiment shown remains unchanged.

[0139] In the Fig. 7 The tread 2 of a pneumatic vehicle tire according to the invention is shown. The tread has four circumferential grooves, the outer grooves 10 and 11 and the inner grooves 12 and 13. The two outer grooves 10 and 11 have a cross-section perpendicular to the circumferential direction, as shown in the Figures 2 to 5 is shown. Accordingly, the two outer grooves 10 and 11 have three groove sections 3, 4, and 5. The two inner grooves 12 and 13, on the other hand, have a V-shaped or U-shaped cross-section perpendicular to the circumferential direction of the tire.

[0140] Accordingly, the Figures 2 to 5 the circumferential groove in cross-section along the Fig. 7 shown section line BB`.

[0141] Due to the inventive design of the outer grooves 10, 11 of the pneumatic vehicle tire shown, the pneumatic vehicle tire possesses both very good wet properties, particularly with regard to aquaplaning, while still maintaining high transverse rigidity, which prevents the formation of groove fractures. This improvement in the profile of the outer grooves 10, 11 particularly ensures permanently uniform rolling and thus permanently uniform stress on the pneumatic vehicle tire. It also accommodates the lateral forces acting on the pneumatic vehicle tire during vehicle operation, which place particular stress on the shoulder area of ​​the pneumatic vehicle tire.

[0142] In Fig. 81 shows a further embodiment of a pneumatic vehicle tire according to the invention, the tread 2. Here, too, the tread 2 has four circumferential grooves. These are two outer grooves 10, 11 and two inner grooves 12, 13. The inner grooves 12, 13 have a U-shaped profile, which can alternatively also be V-shaped. Both outer grooves 10, 11 have two different cross-sections perpendicular to the circumferential direction in partial sections of the circumference. Across the circumference, the partial sections alternate with the two different cross-sections of the circumferential groove perpendicular to the circumferential direction. At the end of one partial section, one cross-section of the circumferential groove merges into the other cross-section of the circumferential groove. In partial sections of the circumferential groove, the cross-section of the circumferential groove is composed of three adjoining groove sections 3, 4, and 5, which are arranged one behind the other in the radial direction R of the pneumatic vehicle tire.Such cross sections of the circumferential groove of a pneumatic vehicle tire according to the invention have been described previously and are shown by way of example in the . Figures 2 to 5 shown. In Fig. 8 In such a section, the line B, B` is shown. It runs through the circumferential groove 11 in the axial direction of the tread 2. The line B, B` is also shown in the Figures 2 to 5 , along which the cross section of the circumferential groove 1 is shown in the figures. In general, the cross section in this circumferential section is characterized by the properties set out in claim 1. Various embodiments of this cross section of the circumferential groove have already been described previously and can also be found in Fig. 8in the tread 2 of the pneumatic vehicle tire. In another section of the circumference of the circumferential groove 11, along the line C, C`, there is a cross-section of the circumferential groove 11 perpendicular to the circumferential direction, which has a V-shaped and preferably a U-shaped profile. Preferably, the U-shaped profile is asymmetrical, wherein the side 8 of the circumferential groove facing the center of the vehicle has a smaller radius of curvature in the bottom region 6 of the circumferential groove. The cross-section used in this section of the circumferential groove is known, for example, from DE 10 2005 042 903 A1. In the embodiment shown, the Fig. 8the subsections with varying cross-sections have the same length in the circumferential direction. However, length ratios of the subsections with the different cross-sections that deviate from this are also possible. Typically, the proportion of the length of the subsections of the circumference of the pneumatic vehicle tire that have a cross-section composed of at least two groove sections 4 and 5 adjoining one another in the radial direction R of the pneumatic vehicle tire, compared to the total length of the subsections over the tire circumference in which both this cross-section and the second cross-section are present, which typically has a U-profile, is between 23% and 75% of the circumference, preferably between 30% and 70% of the circumference, and particularly preferably between 40% and 60% of the circumference.

[0143] If the sections of both existing cross-sections of the circumferential groove have the same length, Fig. 8In the preferred embodiment shown, the arrangement of the subsections on both outer grooves 10 and 11 is such that one cross-section of the circumferential groove is present in one of the two outer grooves and the other cross-section of the circumferential groove is present in the same subsection of the other outer groove. If the subsections for both cross sections in the circumferential groove do not have the same length in the circumferential direction, the subsections on both outer grooves are preferably arranged such that the center of the subsection with a cross-section composed of at least two groove sections adjoining one another in the radial direction of the pneumatic vehicle tire is arranged on one outer groove in the circumferential direction such that the center of the subsection having the other cross-sectional profile, which is preferably a U-profile, is arranged at the same point in the circumferential direction on the other outer groove.

[0144] The alternating cross-sections on the outer grooves of the tire ensure that the preferably U-shaped profile absorbs large amounts of water in wet conditions and the other outer groove absorbs a relatively large amount of water in the second groove section 5. This ensures that the tread 2 of the pneumatic tire can absorb an even amount of water at every circumferential point in order to counteract the risk of aquaplaning. Furthermore, both outer grooves have a high level of transverse rigidity over the entire circumference due to the two different cross-sections in order to counteract groove breakage. In addition, the narrowed first groove section 4 of the cross-section of the circumferential grooves 10, 11, when it is composed of at least two groove sections 4 and 5, ensures improved, i.e. reduced, rolling resistance in the partial sections of the circumference which have such a cross-section.

[0145] In Fig. 9The cross-section of the circumferential grooves 10 and 11 is shown again when the section of these outer grooves 10, 11 has a U-shaped profile. This profile is shown along the section line C, C`, which is shown in the Fig. 8 It can be seen from the Fig. 9 that the bottom region 6 of the circumferential groove 1 shown has different radii of curvature. The radius of curvature of side 8 of the circumferential groove, which faces the center of the pneumatic vehicle tire, is smaller than the radius of curvature of side 9 of the circumferential groove 1, which faces the outside of the pneumatic vehicle tire. This profile of the circumferential groove, which has only one groove section, increases the transverse rigidity of the profile of the tread 2 in the shoulder region of the pneumatic vehicle tire.

[0146] In Fig. 10A further sixth embodiment of a pneumatic vehicle tire according to the invention is shown. In detail, a circumferential groove 1 of the pneumatic vehicle tire is shown, wherein its cross-sectional profile perpendicular to the circumferential direction consists of three groove sections, which are arranged one behind the other in the radial direction R. In the second groove section 5, the radially inner groove section, a structure 14 is arranged, starting from the base region 6 of the circumferential groove 1, which structure is intended to impede or prevent the penetration of small foreign bodies. Otherwise, the sides 8 and 9 of the circumferential groove 1 are designed in the same way as in the Figure 2shown circumferential groove 1. Accordingly, the structure of the second groove section 5 is only changed by the additional outward-facing structure 14. The area of ​​the asymmetrical region of the second groove section 5 is changed by the structure 14, which faces outwards. The area ratios of the asymmetrical region of the second groove section also change accordingly. Such a circumferential groove is part of a pneumatic vehicle tire according to the invention if its cross-section perpendicular to the circumferential direction, without taking into account the cross-sectional area of ​​the structure 14 perpendicular to the circumferential direction, which is additionally arranged in the bottom region of the circumferential groove 1 and faces radially outwards, has a cross-sectional area with the previously described properties of a pneumatic vehicle tire according to the invention.In this exemplary embodiment, the sixth embodiment, in comparison to the previously described embodiments, the structure 14 is only additionally arranged in the bottom region 6 of the circumferential groove 1, which is usually part of the second groove section.

[0147] The additional structure 14 arranged in the base region 6 can have angular structures such as a peak in the region that faces outward in the radial direction and is no longer arranged in the base region 6 of the circumferential groove 1. A peak is a structure in which the gradient of a surface transitions discontinuously from one value to another. In the circumferential direction, the structure 14 can therefore have a degree.

[0148] In a pneumatic vehicle tire according to the invention, the circumferential grooves, which are composed of at least two groove sections 4 and 5 adjoining one another in the radial direction of the pneumatic vehicle tire, typically have a tread depth PT of 5 mm to 18 mm, preferably a tread depth PT of 6 mm to 16 mm, and particularly preferably a tread depth PT of 9 mm to 15 mm.

[0149] If a third groove section 3 is also present, its width GO in the axial direction A on the surface of the tread 2 in the new state of the pneumatic vehicle tire according to the invention is typically 1 mm to 5.5 mm, preferably 3 mm to 5 mm and particularly preferably 3.7 mm to 4.5 mm.

[0150] If a third groove section 3 is present in the cross section of a circumferential groove 1, its height H3 in the radial direction R of these circumferential grooves 1 in the new state of the pneumatic vehicle tire according to the invention is typically 1 mm to 5 mm, preferably 1.5 mm to 4 mm and particularly preferably 1.7 mm to 2.5 mm.

[0151] The height H1 of the first groove section 4 in the radial direction R of these circumferential grooves 1 is, in the event that a third groove section 3 is also present in the cross-section of a circumferential groove 1, typically 1.5 mm to 9 mm, preferably 2.5 mm to 8 mm, and particularly preferably 3.0 mm to 7.5 mm. The height H1 of the first groove section 4 typically corresponds to at least 20% of the tread depth PT, preferably at least 25% of the tread depth PT, and particularly preferably at least 28% of the tread depth PT in the new state of the pneumatic vehicle tire.

[0152] The height H2 of the second groove section 5 in the radial direction R of these circumferential grooves 1 is typically 3 mm to 11 mm, preferably 4 mm to 9.5 mm, and particularly preferably 5 mm to 8 mm. The height H2 of the second groove section 5 typically corresponds to at least 40% of the tread depth PT, preferably at least 45% of the tread depth PT, and particularly preferably at least 50% of the tread depth PT in the new state of the pneumatic vehicle tire.

[0153] The nominal width of the pneumatic vehicle tires 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 embodiments described in the Figures 5 and 6 The nominal width of the pneumatic vehicle tire shown is 315 mm. The nominal width of pneumatic vehicle tires is defined according to the ISO 5775 standard.

[0154] The nominal cross-sectional ratio, ie the ratio of the tire height to the nominal width, is typically 40% to 95% for pneumatic vehicle tires according to the invention, preferably 45% to 80% and particularly preferably 50% to 70%. In the embodiments of the Figures 7 and 8 the ratio of tire height to nominal width is 70%.

[0155] The pneumatic vehicle tires according to the invention typically have 2 to 6 grooves, preferably 3 to 5 grooves and particularly preferably 4 circumferential grooves.

[0156] The distance between the outer grooves of the pneumatic vehicle tires according to the invention and the shoulder of the pneumatic vehicle tire is typically 40 mm to 70 mm, preferably 45 mm to 65 mm and particularly preferably 50 mm to 55 mm. In the embodiments of the Figures 7 and 8 this distance is 52 mm.

[0157] The pneumatic vehicle tires according to the invention are used on wheels which preferably have a rim diameter of 19.5 inches and particularly preferably a rim diameter of 22.5 inches.

[0158] The pneumatic vehicle tires according to the invention are preferably used in buses and trucks. They are typically used for light trucks, preferably for medium-duty trucks, in particular with a total weight of over 7.2 tons, and most preferably for heavy trucks. The pneumatic vehicle tires according to the invention are used particularly for steering wheels and trailer wheels. The pneumatic vehicle tires according to the invention are characterized by low rolling resistance and tire wear. Furthermore, particularly in the wheels mentioned, the inventive design of the cross-sections of the circumferential grooves achieves a significant reduction in crack formation in the tread pattern, especially at the groove base. In particular, the inventive design of the circumferential grooves enables a significantly longer service life of the tires in long-distance vehicles.It is precisely here that a constant, uniform load on the tires occurs, especially in the shoulder area of ​​the tread. The uniform load is greatest on the steering wheels, as their load is independent of the vehicle load and therefore does not vary. The new tread design is able to specifically address these problems, absorbing the stressing forces in a load-appropriate manner and dissipating them into the tire tread.

[0159] The pneumatic vehicle tires according to the invention have circumferential grooves with an improved profile, which contributes to improved wet performance, particularly with regard to aquaplaning, and also increases the lateral stiffness of the tires and thus their grip. In particular, groove breakage in the shoulder area of ​​the pneumatic vehicle tires is prevented by these new circumferential grooves. In addition, the circumferential grooves with the improved profile also contribute to an advantageous, namely lower, rolling resistance.

[0160] The described embodiments represent only examples of the pneumatic vehicle tires according to the invention to explain the invention. List of reference symbols

[0161] 1Circumferential groove 2Tread of a pneumatic vehicle tire 3Outer third groove section 4First groove section 5Second groove section 6Bottom area of ​​the circumferential groove 7Deepest point of the circumferential groove 8Side of the circumferential groove facing the center of the pneumatic vehicle tire 9Side of the circumferential groove facing the outside of the pneumatic vehicle tire 10Outer groove of the pneumatic vehicle tire 11Outer groove of the pneumatic vehicle tire 12Inner groove of the pneumatic vehicle tire 13Inner groove of the pneumatic vehicle tire 14Structure in the bottom area of ​​the circumferential groove 15Straight line of the side of the circumferential groove of the second embodiment facing the outside of the pneumatic vehicle tire 16Straight line of the side of the circumferential groove of the second embodimentfacing the outside of the pneumatic vehicle tire Aaxial direction Rradial direction GOWidth of the first groove section on the surface of the tread GWmaxmaximum width of the cross-sectional area of ​​the third groove section GWminWidth of the first groove section at its innermost point H1Height of the first groove section H2Height of the second groove section H3Height of the third groove section PTTread depth of the pneumatic vehicle tire R1Radius of curvature of the side facing the outside, in the ground area R2Radius of curvature of the side facing the tire center, in the ground area,

Claims

1. Pneumatic vehicle tyre, in particular utility vehicle tyre, having a tread (2) which has a profiling and which has at least one circumferential groove (1) which runs in encircling fashion in the circumferential direction of the pneumatic vehicle tyre, is formed to a profile depth PT and which, at least over at least part of the circumference of the pneumatic vehicle tyre, is made up, in cross section perpendicularly to the circumferential direction, of at least two groove portions adjoining one another in a radial direction R of the pneumatic vehicle tyre, and having a first groove portion (4) which is symmetrical with respect to a line running in the radial direction R of the pneumatic vehicle tyre and the width of which in the axial direction A of the pneumatic vehicle tyre is less than 3 mm and does not vary by more than 10%, preferably not by more than 2% and particularly preferably not by more than 0.5%, and having a radially inner second groove portion (5) which is made wider in the axial direction A in comparison with the first groove portion (4) and has the largest cross-sectional area of all the groove portions, wherein the cross-sectional area of the second groove portion (5) is asymmetrical to the line running in the radial direction R, extends on both sides of the line running in the radial direction R and has an edge without corners in the bottom region (6) of the circumferential groove (1), characterized in that the cross-sectional area of the second groove portion (5) between the line running in the radial direction R and the side (8) of the circumferential groove (1) that faces the centre of the vehicle tyre is between 10% smaller and 15% greater than the cross-sectional area of the second groove portion (5) between the line running in the radial direction R and the side (9) of the circumferential groove (1) that faces the outside of the pneumatic vehicle tyre.

2. Pneumatic vehicle tyre according to Claim 1, characterized in that the edge of the cross-sectional area of the second groove portion (5) in the bottom region (6) of the circumferential groove (1) only has rounded portions.

3. Pneumatic vehicle tyre according to at least one of Claims 1 to 2, characterized in that, in the bottom region (6) of the circumferential groove (1), the side (8) of the circumferential groove (1) has a curvature R2 with the smallest radius of curvature, the curvature facing the centre of the pneumatic vehicle tyre.

4. Pneumatic vehicle tyre according to Claim 3, characterized in that, in the bottom region (6) of the circumferential groove (1) on the side (8) of the circumferential groove (1) that faces the centre of the pneumatic vehicle tyre, the smallest radius of curvature R2 of the curvature is at least 20% smaller than the smallest radius of curvature R1 of the curvature of the other side (9), preferably at least 35% smaller than the smallest radius of curvature R1 of the curvature of the other side (9) and particularly preferably at least 50% smaller than the smallest radius of curvature R1 of the curvature the other side (9).

5. Pneumatic vehicle tyre according to at least one of Claims 1 to 4, characterized in that the at least one circumferential groove (1) running in encircling fashion in the circumferential direction of the pneumatic vehicle tyre and being formed to profile depth PT is an outer groove (10, 11) of the pneumatic vehicle tyre.

6. Pneumatic vehicle tyre according to at least one of Claims 1 to 5, characterized in that the tread (2) comprises two circumferential grooves (1) running in encircling fashion in the circumferential direction of the pneumatic vehicle tyre, being formed to profile depth PT and forming the two outer grooves (10, 11) of the pneumatic vehicle tyre.

7. Pneumatic vehicle tyre according to at least one of Claims 1 to 6, characterized in that, over at least 35% of the height H2 of the second groove portion (5) in the radial direction R, the cross-sectional area of the second groove portion (5), starting from the bottom region (6) of the circumferential groove (1), is asymmetrical to the radial direction R, preferably over at least 50% of the height H2 of the second groove portion (5) in the radial direction R, the cross-sectional area of the second groove portion (5), starting from the bottom region (6) of the circumferential groove (1), is asymmetrical to the radial direction R, and particularly preferably over at least 70% of the height H2 of the second groove portion (5) in the radial direction R, the cross-sectional area of the second groove portion (5), starting from the bottom region (6) of the circumferential groove (1), is asymmetrical to the radial direction R.

8. Pneumatic vehicle tyre according to at least one of Claims 1 to 7, characterized in that the maximum width GWmax of the cross-sectional area of the second inner groove portion (5) perpendicular to the radial direction R is 20% smaller to 50% greater, preferably 5% smaller to 35% greater and particularly preferably 10% to 175% greater than the maximum height H2 of the cross-sectional area of the second inner groove portion (5) in the direction of the radial direction R.

9. Pneumatic vehicle tyre according to at least one of Claims 1 to 8, characterized in that at least one circumferential groove (1) which runs in encircling fashion in the circumferential direction of the pneumatic vehicle tyre and is formed to profile depth PT is made up, over the circumference of the pneumatic vehicle tyre, in at least part of the circumference of the pneumatic vehicle tyre, in cross section perpendicularly to the circumferential direction, of the at least two groove portions adjoining one another in a radial direction R of the pneumatic vehicle tyre, the first groove portion (4) and the second inner groove portion (5) of the pneumatic vehicle tyre, and has a U profile in at least part of the circumference of the pneumatic vehicle tyre as a cross section perpendicular to the circumferential direction.