The invention relates to a pneumatic vehicle tire for utility vehicles having a belt and having a tread profile which extends in an axial direction A of the pneumatic vehicle tire between two tire shoulders, in which tire shoulders there is formed in each case one shoulder profile band which is formed so as to extend over the circumference of the pneumatic vehicle tire and which is delimited, in the axial direction A toward the equatorial plane Ä of the tire, by a channel extending over the circumference of the pneumatic vehicle tire and, on its side pointing away from the equatorial plane Ä, in each case by a surface of the tire side wall, which surface forms that flank of the shoulder profile band which points away from the equatorial plane Ä, wherein, in the section planes that encompass the tire axis, the tread profile is delimited by a surface which forms the road contact surface and which, between the shoulder profile bands, forms a surface contour line K which is curved toward the tire, wherein the surface which forms the road contact surface is, in at least one shoulder profile band, in an axial first extent section of the width a adjacent to the circumferential channel, formed as the elongation of the curved surface contour line K into the shoulder profile band and, in a second extent section of the width c adjoining the first extent section and extending as far as the surface of the tire side wall, declines continuously in terms of its radial position of the tire outwardly along the axial extent.

Pneumatic vehicle tire for utility vehicles having a tread profile which extends in an axial direction A of the pneumatic vehicle tire between two tire shoulders, in which tire shoulders there is formed in each case one shoulder profile band which is formed so as to extend over the circumference of the pneumatic vehicle tire and which is delimited, in the axial direction A toward the equatorial plane Ä of the tire, by a channel extending over the circumference of the pneumatic vehicle tire and, on its side pointing away from the equatorial plane Ä, in each case by a surface of the tire side wall, which surface forms that flank of the shoulder profile band which points away from the equatorial plane, wherein, in the section planes that encompass the tire axis, the tread profile is delimited by a surface which forms the road contact surface and which, between the shoulder profile bands, forms a surface contour line which is curved toward the tire.

Such pneumatic vehicle tires for utility vehicles are known. In the case of tires of this kind, in the cross-sectional planes that encompass the tire axis, the outer contour line in each case forms the intersection line contour of the shell surface formed by the radially outwardly directed surfaces that delimit the profile ribs or profile block elements of profile block rows. Normally, the outer contour line extends with a continuous slight curvature from the intersection line of one tire side wall of the tire with the radially outwardly directed surface of the shoulder band pointing toward said first tire side wall to the intersection line of the other tire side wall with the radially outwardly directed surface of the shoulder band pointing toward said second tire side wall.

It is known, in the case of pneumatic utility vehicle tires of this kind, to make it possible to realize a reduction in the rolling resistance by reducing the profile depth over the entire extent of the tread profile, but this comes at the expense of the wear characteristics of the pneumatic utility vehicle tire.

It is also known for only the shoulder profile band to be formed, over its entire width extent in the axial direction A of the tire, with a reduced profile depth in relation to the profile bands formed between the shoulder profile bands. A pronounced step of the surface contour and of the profile depth is formed as a result in the axial region of extent of the circumferential channel that separates the shoulder profile band from the adjacent profile bands. Such complete reductions of the profile depth in the region of the shoulder bands adversely affect both the wear characteristics and the rolling resistance.

From the German patent application DE 10 2009 044 418.1, it is known, in order to reduce the rolling resistance, for the surface contour of the shoulder band to be formed, in a first axial region of extent adjacent to the separating circumferential channel, so as to follow the surface contour line of the tread profile formed between the shoulder bands, as far as a step in the shoulder band at which the surface contour changes abruptly and, here, the profile depth is significantly reduced. From this step with the surface contour formed in a reduced radial position and with a reduced profile depth, the shoulder band is formed so as to extend as far as the side wall in a second axial region of extent of the shoulder band. This embodiment already leads to significant improvements in rolling resistance. Owing to the significant reduction in rubber material due to the removal of material, there is a slight increase in wear as a result. The abrupt change also permits the formation of cracks.

From WO 2012/126671 A, it is known, in order to reduce the rolling resistance and the wear in the case of a pneumatic vehicle tire of said type, for the surface contour in the shoulder band to be formed initially, in a first extent section which is adjacent to the separating circumferential channel, so as to follow the surface contour line as far as a bend. Then, in an axial second extent section from said bend to the side wall, the surface contour extends rectilinearly so as to be inclined inwardly in a radial direction, enclosing an angle of inclination with respect to the tangent to the surface contour line at the bend. This embodiment, with a type of bevel-like profile of the second extent section, already makes it possible to realize good rolling resistance characteristics with reduced crack formation. However, there is still a relatively large amount of rubber material present in the second extent section. In this embodiment, too, the potential for optimizing the rolling resistance is not yet fully utilized.

The invention is based on the object of providing a pneumatic vehicle tire for utility vehicles, as per the features of claim1of the preamble, in the case of which improved rolling resistance, with a further reduction of crack formation, is made possible using simple means.

The object is achieved according to the invention through the formation of a pneumatic vehicle tire for utility vehicles having a belt and having a tread profile which extends in an axial direction A of the pneumatic vehicle tire between two tire shoulders, in which tire shoulders there is formed in each case one shoulder profile band which is formed so as to extend over the circumference of the pneumatic vehicle tire and which is delimited, in the axial direction A toward the equatorial plane Ä of the tire, by a channel extending over the circumference of the pneumatic vehicle tire and, on its side pointing away from the equatorial plane Ä, in each case by a surface of the tire side wall, which surface forms that flank of the shoulder profile band which points away from the equatorial plane Ä, wherein, in the section planes that encompass the tire axis, the tread profile is delimited by a surface which forms the road contact surface and which, between the shoulder profile bands, forms a surface contour line K which is curved toward the tire, wherein the surface which forms the road contact surface is, in at least one shoulder profile band, in an axial first extent section of the width a adjacent to the circumferential channel, formed as the elongation of the curved surface contour line K into the shoulder profile band and, in a second extent section of the width c adjoining the first extent section and extending as far as the surface of the tire side wall, declines continuously in terms of its radial position of the tire outwardly along the axial extent, as per the features of claim1, in which the surface which forms the road contact surface is, in the second extent section, formed with a first subsection, which extends as far as a point P, and from a second subsection, which extends from the point P to the surface of the tire side wall, and in which the surface which forms the road contact surface is formed with a concavely curved contour profile in the first subsection and with a convexly curved contour profile in the second subsection, with a turning point of the contour profile at the point P, wherein the point P is arranged outside the belt in the axial direction A.

By way of this embodiment, it is made possible for both the rolling resistance and the wear and thus the long-term performance of the tire to be improved. Here, the further improved material distribution in the shoulder outer region permits an optimization of the rolling resistance. The embodiment with the change, formed at the turning point outside the belt, from an initially concave contour profile to a then convex contour profile in the second extent section toward the tire side wall makes it possible here both to realize an improved material distribution—and thus a further improved rolling resistance—and to avoid discontinuous abrupt material changes—and thus crack formation. The embodiment with a concave contour profile formed in the first subsection makes it possible here to realize a smoothing of the contour profile changes, with a highly effective reduction in volume of rubber material. The adjoining convex form of the contour profile permits a further smoothing of the contour profile toward the shoulder, with a further reduction of material. The concave and adjoining convex form with the point P as a turning point thus permit considerable smoothing of the contour profile with a simultaneous material reduction, and hereby promote a further reduction in rolling resistance. The formation of said profile with a turning point axially outside the belt makes it possible to realize a considerable reduction in crack formation. The clear but smoothed material variation owing to the contour profile in the second extent section gives rise, during use under load, to a homogenized load distribution, optimized wear characteristics and, as a result, optimized long-term characteristics of the utility vehicle tire.

By way of this embodiment, it is made possible for both the rolling resistance and the wear and thus the long-term performance of the tire to be improved. The further improved material distribution in the shoulder outer region makes it possible here to realize an optimization of the rolling resistance the embodiment with the change, formed at the turning point outside the belt, from an initially concave contour profile and a convex contour profile toward the tire side wall in the second extent section

The embodiment of a pneumatic vehicle tire as per the features of claim2is particularly advantageous, wherein the first subsection with concavely curved contour profile is formed so as to extend in the axial direction A of the tire from an axial position within the belt extent to the point P outside the belt. This permits greater material reduction and thus a further reduction of the rolling resistance.

The embodiment of a pneumatic vehicle tire as per the features of claim3is particularly advantageous, wherein, in the section planes that encompass the tire axis, the concavely curved contour profile is a contour profile curved with a curvature radius Raabout a curvature central point Ma, wherein the curvature central point Mais arranged outside the contour line on that side of the contour line which points away from the tire. This permits a further smoothing of the material variation by way of a single curvature, and thus a further improvement for the avoidance of crack formation.

The embodiment of a pneumatic vehicle tire as per the features of claim4is particularly advantageous, wherein the curvature radius Rais configured such that 15 mm≤Ra≤100 mm. This makes it possible to realize an optimum compromise between minimization of rolling resistance and good resistance to crack formation.

The embodiment of a pneumatic vehicle tire as per the features of claim5is particularly advantageous, wherein the curvature radius Rais configured such that PT≤Ra, where PTis the maximum profile depth of the tire. This permits a further optimization of the rolling resistance with a relatively small spacing of the point P to the tire axis, while maintaining good resistance to crack formation.

The embodiment of a pneumatic vehicle tire as per the features of claim6is particularly advantageous, wherein, in the section planes that encompass the tire axis, the convexly curved contour profile is a contour profile curved with a curvature radius Riabout a curvature central point Mi, wherein the curvature central point Miis arranged outside the contour line on that side of the contour line which points toward the tire, where Riis configured such that Ri>Ra. This permits a further smoothing of the material variation and thus a further improvement for the avoidance of crack formation. Furthermore, it is possible here, in the contour profile, to realize a type of broad plateau with maximum material reduction, while utilizing the advantages of the smooth transition resulting from the radii, and to optimize the rolling resistance.

The embodiment of a pneumatic vehicle tire as per the features of claim7is particularly advantageous, wherein the curvature radius Riis configured such that 100 mm≤Ri≤2000 mm. In this way, it is possible in a simple manner, in the contour profile, to implement a type of broad plateau with a great material reduction and further reduced rolling resistance.

The embodiment of a pneumatic vehicle tire as per the features of claim8is particularly advantageous, wherein the width c is configured such that 5 mm≤c≤30 mm. In this way, it is possible in a simple manner to implement an adequately large width c for the optimization of the rolling resistance, and also a sufficiently small width c for improvements for avoidance of crack formation, while avoiding significant adverse effects on good handling characteristics.

The embodiment of a pneumatic vehicle tire as per the features of claim9is particularly advantageous, wherein the point P is arranged in the axial direction A with a spacing d, measured in the axial direction A, of 5 mm≤d≤10 mm to the belt. In this way, it is possible in a simple manner to promote a homogenization of the material distribution.

The embodiment of a pneumatic vehicle tire as per the features of claim10is particularly advantageous, wherein the point P is arranged at a radial position radially within the radial position of a point Q with a radial spacing e to the point Q, where 0 mm≤e≤2 mm, wherein the point Q forms the position of the intersection of the elongation of the profile depth contour line KPwith the contour profile concavely curved in the first subsection. In this way, it is possible in a simple manner for the rubber thickness to be made sufficiently thick toward the belt edge for the purposes of high durability, and to nevertheless realize a significant material reduction.

The embodiment of a pneumatic vehicle tire as per the features of claim11is particularly advantageous, wherein the profile band is in the form of a profile rib. In conjunction with profile ribs, a maximum material reduction can be implemented. In this way, the effects of the contour profile can be utilized in an optimized manner.

The embodiment of a pneumatic vehicle tire as per the features of claim12is particularly advantageous, wherein the profile band is in the form of a profile block row.

The embodiment of a pneumatic vehicle tire as per the features of claim13is particularly advantageous, wherein the pneumatic vehicle tire is designed for use on the drive axle of a utility vehicle.

