VEHICLE TIRES WITH AERODYNAMICLY ADVANTAGEOUS SURFACE STRUCTURE

Description

[0001] The invention relates to a vehicle tire with an aerodynamically advantageous surface structure and a method for manufacturing such a vehicle tire. A vulcanization mold for use in such a method and the use of a plurality of specific structural elements for improving the aerodynamic properties of a vehicle tire are also disclosed.

[0002] As a result of growing awareness of the need for a more sustainable use of fossil fuels and the reduction of greenhouse gas emissions, there has been a steady interest in minimizing vehicle fuel consumption in recent years. Significant progress has been made in this area, particularly through the use of modern vehicle tires. In the field of vehicle tires, development efforts to reduce fuel consumption have largely focused on optimizing rolling resistance, with the design of the tread and the internal structure of the tire being the primary focus of development in the past. The aerodynamic properties of vehicle tires, and their contribution to a vehicle's overall drag coefficient, have, however, received relatively little attention in many applications, especially in the area of ​​passenger car tires.In contrast, minimizing the drag of vehicle bodies, as can be achieved in a wind tunnel, is no longer reserved solely for motorsport. When tires are used on a vehicle, however, they are not usually completely enclosed by the bodywork, meaning that the tire sidewalls and shoulders are also exposed to the airflow and thus contribute to the overall aerodynamic profile of the vehicle.

[0003] Although the tread of a vehicle tire is fundamentally the most important factor in its handling characteristics, the surface texture and structure of the tire sidewalls and shoulder also influence the aerodynamic drag of the tire. Despite this, tire sidewalls and shoulders are nowadays primarily used for identification purposes, such as displaying information about the tire manufacturer and / or tire type, or adorned with decorations that primarily serve to enhance the tire's appearance.

[0004] Such markings or decorations are usually achieved through surface texturing in the rubber, with raised and / or recessed areas in the corresponding sections of the tire. During tire manufacturing, these textures are typically embossed into the tire blanks using a complementary vulcanization process. Numerous surface texturings on tire surfaces are known in the prior art, many of which are achieved by arranging groove structures, as disclosed, for example, in US 10105995 B2, US 2020 / 070591 A1, and JP 5789274 B2. However, such surface texturings are generally designed solely for visual purposes and usually offer no benefit to the tire's aerodynamics or intentionally improve its aerodynamic properties.

[0005] Further state of the art is formed by EP 2 730 435 A1: Aerodynamic vehicle tire structural areas with circumferential elevations arranged in recesses are known from this.

[0006] In other fields, such as aviation and shipping, it is known that smooth surfaces are not necessarily preferable to structured surfaces with regard to aerodynamic effects. In recent years, significant improvements in drag reduction have been achieved with structured surfaces, for example, by taking inspiration from nature. For instance, the use of surface structures inspired by shark scales, so-called "riblet films," on the surface of aircraft and / or the hull of ships has resulted in a significant reduction in drag.

[0007] Conversely, an aerodynamically unfavorable surface structuring, for example as a result of structuring focused solely on optical aspects, can lead to an unfavorable increase in the flow resistance, which is composed of pressure resistance and frictional resistance, of the object in question.

[0008] Against this background, some attempts have been made to improve the aerodynamic properties of vehicle tires through targeted surface texturing in the area of ​​the tire sidewall or shoulder, or at least to minimize the negative influence of markings and decorations. However, the aerodynamic effects of the solutions known from the prior art are often considered insufficient. Furthermore, the texturing methods known from the prior art for this purpose are usually complex and expensive to manufacture, as they require, for example, technically sophisticated tools for incorporating the vulcanization mold and / or further processing steps to achieve the desired effect.

[0009] The primary objective of the present invention was to eliminate or at least reduce the disadvantages of the prior art described above.

[0010] In particular, the object of the present invention was to provide a vehicle tire which has improved aerodynamic properties compared to the prior art, so that in particular the flow resistance of the vehicle tire to be provided is minimized when used on the vehicle and should therefore be lower in particular compared to conventional vehicle tires.

[0011] The requirement was that the reduction of the flow resistance of the specified vehicle tire should be achieved by changing the surface texture in the tire sidewall and / or tire shoulder of the specified vehicle tire.

[0012] In this respect, a further objective of the present invention was that the resulting surface of the vehicle tires in question should, while having an advantageous influence on the aerodynamic properties, nevertheless allow the greatest possible freedom in terms of marking and design. Accordingly, the vehicle tire in question should, in particular, resolve the conflicting objectives of an aesthetically pleasing surface structure and improved aerodynamic properties in the best possible way.

[0013] An additional objective of the invention was to make the production of the specified vehicle tire particularly time- and cost-efficient, with the surface structuring preferably being able to be applied directly in the vulcanization process.

[0014] Furthermore, it was an object of the present invention to provide a method for manufacturing a corresponding vehicle tire.

[0015] Furthermore, a secondary objective of the present invention was to specify the use of a plurality of structural elements to improve the aerodynamic properties of a vehicle tire.

[0016] Finally, a secondary object of the present invention was to provide a vulcanization mold for the production of corresponding vehicle tires, in particular for use in the process to be specified.

[0017] The inventor has now realized that the problems described above can surprisingly be solved by arranging a multitude of specific structural elements in a structural region of the tire shoulder and / or the tire sidewall, wherein the structural elements each have at least three nested, circumferential projections, which are separated from one another by groove-like recesses and whose height differs from one another relative to the depth of the encompassed recesses, as defined in the claims. This surprisingly results in a particularly aerodynamically advantageous surface structure, which advantageously minimizes the drag of the vehicle tire, and the production of corresponding vehicle tires is also advantageously particularly time- and cost-efficient.

[0018] The aforementioned problems are solved accordingly by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention are described in the dependent claims and the following descriptions.

[0019] Such embodiments, which are hereinafter referred to as preferred, are combined in particularly preferred embodiments with features of other embodiments also referred to as preferred. Combinations of two or more of the embodiments hereinafter referred to as particularly preferred are therefore especially preferred. Also preferred are embodiments in which a feature of one embodiment, referred to as preferred to any extent, is combined with one or more further features of other embodiments, which are referred to as preferred to any extent. Those skilled in the art understand that, in particular, embodiments are preferred which have two or more features that are also shown in the figures for the particularly preferred examples. Features of preferred methods, uses, and vulcanization methods result from the features of preferred vehicle tires.

[0020] The invention relates to a vehicle tire comprising, in the area of ​​at least one tire shoulder and / or at least one tire sidewall, a structural area, wherein the structural area comprises a plurality of structural elements arranged on the surface of the vehicle tire,

[0021] wherein the structural elements each comprise a circumferential first elevation with a first plateau surface, a circumferential second elevation surrounding the first elevation with a second plateau surface and a circumferential third elevation surrounding the second elevation with a third plateau surface,

[0022] wherein the first elevation surrounds a recess with a first bottom surface, wherein the second elevation is delimited from the first elevation by a circumferential groove element with a second bottom surface, wherein the third elevation is delimited from the second elevation by a circumferential groove element with a third bottom surface, wherein: H1 is the mean height difference between the first plateau surface and the first ground surface, H2 is the mean height difference between the second plateau surface and the second ground surface, H3 is the mean height difference between the third plateau surface and the third ground surface, and where within each structural element H 1 , H 2 and H 3 are different from each other.

[0023] An example is a vehicle tire according to the invention, wherein the vehicle tire is a passenger car or truck tire, preferably a passenger car tire. For most cases, a vehicle tire according to the invention is relevant, wherein the vehicle tire is a pneumatic tire. Also relevant for most cases is a vehicle tire according to the invention, wherein the vehicle tire has a tread, the tread having a profile.

[0024] The vehicle tire according to the invention comprises a structural area in the region of the tire shoulder and / or the tire sidewall, i.e., at least a region of the tire surface in which the structural elements are arranged. In principle, a structural area can be arranged either exclusively on the tire shoulder or on the tire sidewall. However, it is also possible to arrange a single structural area on both the tire sidewall and the tire shoulder, so that the structural area at least partially covers both regions. A preferred configuration, however, is a vehicle tire according to the invention in which the vehicle tire comprises the structural area in the region of at least one tire sidewall, preferably both tire sidewalls.

[0025] In accordance with the skilled person's understanding, the vehicle tire according to the invention can comprise a plurality of structural areas, whereby, in the inventor's opinion, a larger number of structural areas promotes advantageous aerodynamic properties, since this regularly allows for a larger surface area and simultaneously leaves open the option of providing markings or decorations between the structural areas. In a particularly preferred embodiment, these structural areas are distributed uniformly over the vehicle tire, thereby achieving more uniform flow behavior, especially if the various structural areas are similar with regard to the dimensions and design of the structural elements. In this embodiment, the plurality of structural areas is preferably separated by a plurality of marking areas, i.e.,Areas of the sidewall where a marking or decoration is arranged that does not primarily serve to improve aerodynamic properties. In this respect, the number of structural areas is expediently based on the number of marking areas, so that the tire sidewall and / or tire shoulder is preferably covered substantially completely by the structural areas and the marking areas. A preferred vehicle tire according to the invention comprises two or more, preferably four or more, and particularly preferably six or more separate structural areas distributed over at least one tire sidewall and / or tire shoulder, wherein the structural areas are preferably separated from one another by marking areas that serve to identify the vehicle tire, in particular with manufacturer information, warnings, or product information.

[0026] As explained above, the inventor believes that, for the optimization of aerodynamic properties, it is advantageous to provide the most comprehensive coverage of the tire surface with the beneficial structural areas in order to fully exploit the positive effects of the surface structuring, and accordingly to select the largest possible extent of the structural areas in both the circumferential and radial directions. A preferred vehicle tire according to the invention is therefore one in which the combined surface area of ​​all structural areas on a tire sidewall or tire shoulder is 10% or more, preferably 20% or more, and particularly preferably 30% or more, based on the surface area of ​​the tire sidewall or tire shoulder.A preferred vehicle tire according to the invention is also one in which at least one structural region, preferably all structural regions, extends along the circumferential direction over 10% or more, preferably 15% or more, and particularly preferably 20% or more, of the tire circumference. A preferred additional or alternative vehicle tire according to the invention is also one in which at least one structural region, preferably all structural regions, extends at least partially, preferably over the entire length in the circumferential direction, along the radial direction of the vehicle tire over 20% or more, preferably 30% or more, and particularly preferably 40% or more, of the tire height, wherein the tire height is the distance between the lower edge of the tire bead and the surface of the tread.

[0027] According to the invention, the structural area comprises a plurality of structural elements arranged on the surface. A vehicle tire according to the invention is preferred in this respect, wherein at least one structural area, preferably all structural areas, comprises ten or more, preferably twenty or more, particularly preferably 30 or more, structural elements, and structural areas with several hundred structural elements are also conceivable in principle.

[0028] Those skilled in the art understand that while the structural elements could theoretically also be attached to the tire surface, for example by means of an adhesive, this is unlikely to be of overly significant practical relevance. Rather, for essentially all embodiments, a vehicle tire according to the invention is relevant, wherein the structural elements are part of the tire shoulder or the tire sidewall, or wherein the structural elements are formed by structuring the surface of the vehicle tire, so that the structural elements consist essentially of the same material, in particular a rubber material, as the tire shoulder or the tire sidewall.

[0029] The structural elements can, in principle, be randomly distributed within the structural area, and in this case, the structural area is defined by the envelope surrounding all structural elements. It is also possible for the structural elements to be unevenly distributed within the structural area, resulting in differences in density. This is particularly necessary if the structural area contains other elements besides the structural elements, such as marking elements arranged within the structural area. However, in all cases, it is preferable for the structural area to be covered by structural elements as comprehensively as possible.A preferred vehicle tire according to the invention is therefore one in which the structural elements are arranged in at least one structural area, preferably in all structural areas, such that the structural elements in the structural area have a combined area fraction of 80% or more, preferably 90% or more, particularly preferably substantially 100%, based on the area of ​​the structural area.

[0030] In all embodiments, it is preferred that the structural elements within the structural area are arranged regularly, whereby the distances between the elements should not be chosen too large in the inventors' opinion for a particularly effective coverage density. A preferred option is therefore a vehicle tire according to the invention, wherein the structural elements are arranged in a regular pattern in at least one structural area, preferably in all structural areas.A vehicle tire according to the invention is also preferred, wherein the centers of the nearest adjacent structural elements have a distance in the range of 0.7*A to 1.3*A, preferably in the range of 0.8*A to 1.2*A, particularly preferably in the range of 0.9*A to 1.1*A, wherein A is the mean distance of the centers of the nearest adjacent structural elements, wherein the centers of the nearest adjacent structural elements are preferably arranged substantially equidistant from each other.

[0031] With regard to the arrangement of the structural elements, it has also proven advantageous, in light of the foregoing explanations concerning the densest possible packing of the structural elements, if these are arranged at least partially butt-jointed. A preferred vehicle tire according to the invention is therefore one in which the structural elements are arranged at least partially, preferably predominantly, and particularly preferably substantially completely butt-jointed with other structural elements in at least one structural region, preferably in all structural regions, so that the outer circumferential projections of the butt-jointed structural elements are not separated from one another by a recess, at least in sections.

[0032] To achieve the most complete possible coverage of the structural area, it can generally be advantageous to provide different geometric shapes for the structural elements within that area. However, in most cases, it is more practical to design the structural elements to be essentially identical and symmetrical, as the inventor believes this results in particularly favorable aerodynamic properties. Therefore, a vehicle tire according to the invention is preferred in which the structural elements in at least one structural area, preferably in all structural areas, have the same basic geometric shape and arrangement to 50% or more, preferably 70% or more, particularly preferably 90% or more, and most preferably essentially completely, so that the structural elements can be scaled in size to obtain essentially identical structural elements.Preferably, or alternatively, a vehicle tire according to the invention is also used, wherein the structural elements are at least partially, preferably predominantly, and particularly preferably all, symmetrical, preferably mirror-symmetrical about at least two mirror planes and / or rotationally symmetrical C n, where n is greater than 2. In accordance with the skilled person's understanding, the foregoing definition of the same basic geometric shape and arrangement means that the structural elements differ essentially only in their scaling.

[0033] According to the invention, the structural elements each comprise a first projection surrounding a recess, a second projection enclosing the first, and a third projection enclosing the second, with the projections being separated from each other by groove elements. The structural elements thus comprise at least three nested, circumferential surface projections, which, apart from their specific shape and relative arrangement, are in many respects comparable to conventional hatching patterns used for marking purposes. As explained below, however, further circumferential projections can also be provided, which are then in turn separated from the more internal projections by a groove element. The projections each comprise a plateau surface at their apex, i.e., they are flattened, and the groove elements or the recess form a base surface extending along their lowest point.In accordance with the skilled person's understanding, the term "circumferential" means that the elements are essentially closed, ring-like elements that substantially completely surround the elements located further inside. The skilled person understands that minor deviations from a perfect enclosure, which may arise, for example, from manufacturing defects such as gaps in a circumferential projection, do not affect whether an element is considered a circumferential element. According to the invention, an element is considered circumferential in any case if it surrounds the element it surrounds to 98% or more, preferably 99% or more, particularly preferably 99.5% or more, and most preferably 99% or more, with respect to the circumference of the surrounded element.

[0034] In light of the foregoing, particularly regarding the symmetrical design of the structural elements, it is explicitly preferred that all plateau surfaces have a similarly oriented geometric shape, allowing them to be transformed into one another by central scaling. This means, for example, that the three protrusions all have a hexagonal shape and are nested within each other as three hexagons of different sizes. This results in a particularly uniform surface structure, which, in the inventor's estimation, has a particularly favorable effect on the aerodynamic properties of the vehicle tires.A preferred vehicle tire according to the invention is one in which the first, second, and third plateau surfaces, and preferably also all further plateau surfaces in the structural element, have outer outlines that can be transformed into one another by central stretching. A preferred vehicle tire according to the invention is also one in which the first, second, and third base surfaces, and preferably also all further base surfaces in the structural element, have outer outlines that can be transformed into one another by central stretching.

[0035] Furthermore, it is also advantageous if the first, second, and third protrusions are arranged around a common center point, i.e., concentrically. Accordingly, in this embodiment, the geometric centers of the first, second, and third plateau surfaces, as well as the geometric centers of the first, second, and third base surfaces, coincide with the same point. A preferred vehicle tire according to the invention is therefore one in which the first, second, and third protrusions are arranged essentially concentrically with each other.

[0036] In principle, the raised sections can be designed with different cross-sectional profiles perpendicular to the direction of rotation, for example, with polygonal cross-sectional profiles. Particularly with a polygonal cross-sectional profile, the raised sections advantageously have at least one, preferably two, inclined sidewalls. In this case, all raised sections in the cross-sectional view have a geometric shape corresponding to an isosceles trapezoid, which, according to the inventors, promotes advantageous airflow behavior of the structural elements. A vehicle tire according to the invention is preferred, wherein the first raised section and / or the second raised section and / or the third raised section, preferably all raised sections, have a sidewall that runs at an angle relative to the corresponding base surface in the range of 35° to 90°, preferably in the range of 45° to 80°, and particularly preferably in the range of 55° to 70°.A preferred vehicle tire according to the invention is therefore one in which the first projection and / or the second projection and / or the third projection, preferably all projections, have a square cross-sectional area transverse to the center line, preferably a rectangular or trapezoidal cross-sectional area, particularly preferably a trapezoidal cross-sectional area.

[0037] Regarding the further design of the structural elements, the inventor has identified dimensions that have proven particularly advantageous in practice. In this respect, it is advantageous with regard to the aerodynamic properties of the structural elements if all plateau surfaces and all base surfaces exhibit as little variation as possible in their dimensions. The same applies to the opening width of the groove elements. A vehicle tire according to the invention is preferred, wherein the first projection and / or the second projection and / or the third projection, preferably all projections, have plateau surfaces whose mean rib width transverse to the centerline is in the range of 0.01 to 1.0 mm, preferably in the range of 0.02 to 0.5 mm, and particularly preferably in the range of 0.05 to 0.25 mm.A preferred vehicle tire according to the invention is one in which the first projection and / or the second projection and / or the third projection, preferably all projections, have plateau surfaces whose web width varies transversely to the center line over the entire circumference by 10% or less, preferably 5% or less, and particularly preferably 1% or less. A preferred vehicle tire according to the invention is also one in which the groove elements within a structural element, preferably over all structural elements, have an opening width transverse to the center line that varies over the entire circumference by 10% or less, preferably 5% or less, and particularly preferably 1% or less, wherein the groove elements preferably have the same mean opening width.

[0038] According to the invention, H1 denotes the height difference between the first plateau surface and the first ground surface. Similarly, H2 and H3 denote the height differences between the second and third plateau surfaces, respectively, and the corresponding second and third ground surfaces. H1, H2, and H3 are expressed as the mean height difference, i.e., the difference between the mean height of the respective plateau surface and the mean height of the respective ground surface. The height difference is determined, in accordance with the skilled person's understanding, along the axis that is orthogonal to the surface of the vehicle tire in the region of the structural element.

[0039] According to the invention, the height differences H1, H2, and H3 in each structural element are different from one another. Different structural elements within the same structural area can have different H1, H2, and H3 values, so that, at least theoretically, each structural element within a single structural area can exhibit different height differences.

[0040] With a view to achieving the most uniform surface structuring and the most homogeneous flow characteristics possible, the inventors consider it advantageous if the influence of averaging on these values ​​is low, since the grooves and protrusions are largely uniform in height and depth. A preferred vehicle tire according to the invention is therefore one in which the height difference between the first plateau surface and the first base surface varies by 10% or less, preferably 5% or less, and particularly preferably 1% or less, over the entire circumference of the structural element. A preferred additional or alternative vehicle tire according to the invention is one in which the height difference between the second plateau surface and the second base surface varies by 10% or less, preferably 5% or less, and particularly preferably 1% or less, over the entire circumference of the structural element.In addition, or alternatively, a vehicle tire according to the invention is preferred, wherein the height difference between the third plateau surface and the third floor surface varies by 10% or less, preferably 5% or less, particularly preferably 1% or less, over the entire circumference of the structural element.

[0041] With regard to the dimensions of the structural elements, the inventor has identified particularly suitable size ranges in which the advantages of the present invention are especially evident. Specifically, it has proven advantageous with respect to the aerodynamic properties of the structural elements to make them relatively small, particularly compared to typical markings in marking areas, so that the structural elements ideally have a size of approximately 4 to 5.5 mm. A vehicle tire according to the invention is preferred in that the structural elements have at least some, preferably predominantly, and most preferably all, an element size in the range of 3 to 8.5 mm, preferably in the range of 3.5 to 7 mm, and most preferably in the range of 4 to 5.5 mm, where the element size is the greatest distance between two points on the outer contour of the plateau surface of the outermost elevation.Determining the element size is straightforward for a specialist. For example, the element size of a circular structural element corresponds to its diameter, that of a square to its diagonal, and that of a hexagon to the distance between two opposite corners.

[0042] As a particularly advantageous further development of the above-disclosed arrangement of the structural elements abutting other structural elements, the inventor proposes that the structural elements can overlap in the outer areas and even partially divide the outermost projection. This means that a projection section within the structural area can be assigned to two different structural elements, forming part of the outer projection of each. In this case, a surface structuring is created in which the positive effects of the structural area provided according to the invention can be particularly well developed, and in particular, a very dense surface covering can be achieved.This design also has the advantage of being particularly easy to manufacture, since corresponding vulcanization molds can be produced in a particularly time- and cost-efficient manner thanks to simplified milling tool guidance, resulting in a synergistic effect between aerodynamic advantages and particularly simple manufacturing. A preferred design is a vehicle tire according to the invention, wherein the structural elements in at least one structural region, preferably in all structural regions, are arranged at least partially, preferably predominantly, and most preferably substantially completely, side by side such that the outer circumferential protrusions are formed section by section by the same raised structure.A vehicle tire according to the invention is also preferred, wherein the structural elements in at least one structural area, preferably in all structural areas, are arranged at least partially, preferably predominantly, and particularly preferably essentially completely next to each other in such a way that a composite of a plurality of structural elements is obtained in the structural area, in each of which the outer circumferential elevation is formed by the same raised structure.

[0043] To achieve comprehensive surface coverage despite the curved shape of tire sidewalls and dense packing of structural elements, the inventor proposes varying the size of the structural elements in the radial direction of the tire. Excellent surface coverage is achieved, in particular, when the radially inner structural elements are smaller than those radially outer. The variation in size between inner and outer structural elements can be, for example, 5%. This means that for inner structural elements with a size of 5 mm, the size of radially outer structural elements corresponds to approximately 5.25 mm.A preferred vehicle tire according to the invention is one in which at least one structural area, preferably all structural areas, extend along the circumferential direction of the vehicle tire, wherein the structural elements in the structural area have different dimensions along the radial direction, wherein the structural elements located on the inside in the radial direction are preferably smaller than the structural elements located on the outside in the radial direction.

[0044] In some embodiments of the vehicle tire according to the invention, it can be advantageous to provide further projections in some, preferably all, of the structural elements, in addition to the first, second, and third projections. These projections are accordingly delimited from the adjacent projections with lower numbers by further circumferential groove elements, the preceding descriptions of the configurations of the projections and groove elements applying accordingly. In the inventor's opinion, structural elements with a total of six projections are suitable for certain applications. However, in most cases, structural elements comprising exactly three circumferential projections are preferred. This has proven particularly advantageous in practice for obtaining an aerodynamically advantageous structure according to the invention while simultaneously minimizing manufacturing costs.For certain applications, a vehicle tire according to the invention is preferred, wherein the structural elements have at least partially, preferably predominantly, particularly preferably all, further circumferential (n)-th elevations with further (n)-th plateau surfaces, which surround the (n-1)-th elevation, wherein each (n)-th elevation is delimited from the (n-1)-th elevation by a circumferential groove element with an (n)-th bottom surface, wherein . H n is the mean height difference between the (n)th plateau surface and the (n)th ground surface, where H n preferably within each structural element of H 1 , H 2 and H 3 is different, where H n especially preferred is larger than H 3 , where H n especially preferred is larger than H (m <n) However, a vehicle tire according to the invention is particularly preferred, wherein the structural elements comprise at least partially, preferably predominantly, and especially preferably all, exactly three circumferential projections.

[0045] A major advantage of the present invention is that the structural elements can, in principle, have a wide variety of possible geometric shapes, allowing, for example, the selection of deliberately irregular outer contours. In this respect, the inventor has succeeded in identifying particularly advantageous shapes for the structural elements. Hexagons, in particular, allow for excellent surface coverage of the structural areas with structural elements, provided the vulcanization mold is readily manufacturable. This ease of manufacturability is due, for example, to the simplified guidance of the milling tools compared to round structures. The shape of the raised areas and the grooved elements is advantageously complementary.A preferred vehicle tire according to the invention is, wherein the first plateau surface and / or the second plateau surface and / or the third plateau surface, preferably all plateau surfaces, have an outer outline whose shape is selected from the group consisting of polygons and ellipses, preferably from the group consisting of hexagons, quadrilaterals and circles, particularly preferably from the group consisting of squares and hexagons, and most preferably from the group consisting of hexagons.Preferably, or alternatively, a vehicle tire according to the invention is also used, wherein the first floor surface and / or the second floor surface and / or the third floor surface, preferably all floor surfaces, have an outer outline whose shape is selected from the group consisting of polygons and ellipses, preferably from the group consisting of hexagons, quadrilaterals and circles, particularly preferably from the group consisting of squares and hexagons, and most preferably from the group consisting of hexagons.

[0046] In the vehicle tire according to the invention, the height differences H1, H2, and H3, as explained above, are of varying magnitudes within a structural element. The inventor discovered that, surprisingly, particularly advantageous aerodynamic effects result when H1, H2, and H3, relative to the nested structure, increase successively from the inside out, such that the outer elevations are higher than the inner elevations. In this case, a particularly advantageous dimpled structure is created, which exhibited particularly favorable aerodynamic properties in the inventor's experiments. Without being bound by this theory, it is assumed that this dimpled structure and the resulting effects are comparable to those observed in the specific surface design of a golf ball.The so-called "dimples" in the surface structure of the golf ball demonstrably reduce the pressure resistance (as part of the total flow resistance) of the golf ball. For essentially all embodiments, a vehicle tire according to the invention is preferred, wherein within each structural element H1 is smaller than H2, preferably by 20% or more, particularly preferably by 30% or more, and most preferably by 40% or more. For essentially all embodiments, an additionally or alternatively, a vehicle tire according to the invention is also preferred, wherein within each structural element H2 is smaller than H3, preferably by 10% or more, particularly preferably by 20% or more, and most preferably by 30% or more.For essentially all embodiments, a vehicle tire according to the invention is particularly preferred, wherein within each structural element H 1 < H 2 < H 3, wherein it is particularly preferred that the mean height differences between the (n)th plateau surface and the (n)th ground surface increase with increasing (n), wherein in particular H n < H (n+1) .

[0047] For the height differences H1, H2, and H3, the inventors have identified particularly suitable absolute dimensions under which the advantages of the invention are especially reliably demonstrated in practice for typical vehicle tires. A preferred vehicle tire according to the invention has H1 in the range of 0.05 to 0.35 mm, preferably in the range of 0.1 to 0.3 mm, and particularly preferably in the range of 0.15 to 0.25 mm. A preferred vehicle tire according to the invention has H2 in the range of 0.25 to 0.55 mm, preferably in the range of 0.3 to 0.5 mm, and particularly preferably in the range of 0.35 to 0.45 mm. A further preferred vehicle tire according to the invention has H3 in the range of 0.45 to 0.75 mm, preferably in the range of 0.5 to 0.7 mm, and particularly preferably in the range of 0.55 to 0.65 mm.

[0048] In the vehicle tires according to the invention, the height differences H1, H2, and H3 differ from one another in each of the structural elements. The inventor's experiments have shown that particularly advantageous aerodynamic properties result when all base surfaces are essentially at the same height relative to each other. In the corresponding embodiment, the first plateau surface, the second plateau surface, the third plateau surface, and any further plateau surfaces that may be present are arranged at different heights to achieve the necessary differences in Hn. This not only simplifies the manufacturing of the corresponding vehicle tire using a vulcanization mold but also ensures that the tire sidewall and / or the tire shoulder, which contains the structural area, can be vented particularly well.A preferred vehicle tire according to the invention is one in which the first base surface, the second base surface, and the third base surface, and preferably also all further base surfaces in the structural element, are at the same height relative to each other, with respect to the direction orthogonal to the tire surface. A preferred vehicle tire according to the invention is one in which the first plateau surface, the second plateau surface, and the third plateau surface, and preferably also all further plateau surfaces in the structural element, are at different heights with respect to the direction orthogonal to the tire surface.

[0049] It is preferred if the plateau surfaces, and in the case of an increasing height difference, in particular the outermost plateau surface of the structural element, have a maximum height equal to that of the tire surface surrounding the structural area. This can be achieved by designing the central surface of the structural area to be lower than the tire surface surrounding the structural area. With regard to the aerodynamic properties of the vehicle tire according to the invention, this has the advantage that the structural area does not have any raised structures compared to the surrounding tire surface that could negatively affect the aerodynamics of the vehicle tire. Accordingly, it is also preferred in this case if all bottom surfaces are axially lower than the tire surface surrounding the structural area.A preferred vehicle tire according to the invention is one in which the first plateau surface and / or the second plateau surface and / or the third plateau surface and / or further plateau surfaces, preferably the outermost plateau surfaces in the structural element, are at the same height as or lower than the tire surface surrounding the structural area, with respect to the direction orthogonal to the tire surface. A preferred additional or alternative vehicle tire according to the invention is one in which the first base surface and the second base surface and the third base surface, preferably also all further base surfaces in the structural element, are lower than the tire surface surrounding the structural area, with respect to the direction orthogonal to the tire surface.

[0050] The invention also relates to a method for manufacturing a vehicle tire according to the invention, comprising the following process steps: a) Manufacturing an unvulcanized vehicle tire blank comprising a vulcanizable rubber compound in at least one component, and b) vulcanizing the unvulcanized vehicle tire blank in a vulcanization mold to obtain a vehicle tire, wherein the vulcanization mold comprises an embossing structure area in a region provided for the formation of a tire shoulder and / or tire sidewall, wherein the embossing structure area comprises a plurality of embossing structure elements arranged on the surface of the vulcanization mold, wherein the embossing structure elements each comprise a circumferential first embossing groove element with a first embossing base surface, a circumferential second embossing groove element surrounding the first embossing groove element with a second embossing base surface, and a circumferential third embossing groove element surrounding the second embossing groove element with a third embossing base surface.wherein the first embossing groove element surrounds an embossing raised area with a first embossing plateau surface, wherein the second embossing groove element is delimited from the first embossing groove element by a circumferential embossing raised area with a second embossing plateau surface, wherein the third embossing groove element is delimited from the second embossing groove element by a circumferential embossing raised area with a third embossing plateau surface, wherein: T1 is the mean height difference between the first embossing plateau surface and the first embossing base surface, T2 is the mean height difference between the second embossing plateau surface and the second embossing base surface, T3 is the mean height difference between the third embossing plateau surface and the third embossing base surface, and wherein within each embossing structure element T1, T2, and T3 are distinct from one another.

[0051] The method according to the invention serves to manufacture vehicle tires which comprise at least one structural area as disclosed above.

[0052] In process step a), an unvulcanized vehicle tire blank is produced, which can be done, for example, using a conventional vehicle tire building process. Such methods for producing an unvulcanized vehicle tire blank are known to those skilled in the art. For example, production takes place on a tire building drum. Such tire building drums usually have a rotatable mounting device for the various parts of the vehicle tire blank, which are typically arranged layer by layer on this drum and are regularly part of the standard equipment of a tire manufacturer. In most cases, a method according to the invention is relevant, wherein the production of the unvulcanized vehicle tire blank comprises the superimposed arrangement of several layers, in particular carcass layers and / or belt layers.

[0053] The unvulcanized vehicle tire blank comprises a vulcanizable rubber compound in at least one component, from which it follows, in accordance with the skilled person's understanding, that the unvulcanized vehicle tire blank can also be vulcanized. It can be considered an advantage of the method according to the invention that it is not limited with regard to the vulcanizable rubber compound used, so that all rubber compounds commonly used in tire manufacturing can be employed.An exemplary method according to the invention is wherein the vulcanizable rubber mixture comprises at least one diene rubber, wherein the diene rubber is preferably selected from the group consisting of natural polyisoprene, synthetic polyisoprene, epoxidized polyisoprene, butadiene rubber, solution polymerized styrene-butadiene rubber, emulsion polymerized styrene-butadiene rubber, polynorbornene, ethylene-propylene diene rubber, styrene-isoprene-butadiene terpolymer, and isoprene-butadiene copolymer.

[0054] The person skilled in the art understands that the present method according to the invention is carried out such that the vulcanization mold used in the method corresponds to the negative of the vehicle tire according to the invention described above, which imprints the structural area into the vulcanizable rubber compound. It is thus a method according to the invention, wherein the vulcanization is carried out in such a way that the structural area in the vehicle tire is formed as a negative of the imprinted structural area of ​​the vulcanization mold, for example in the area of ​​the tire shoulder or the tire sidewall.

[0055] In this respect, the raised areas in the vulcanization mold of the vehicle tire according to the invention correspond to correspondingly complementary shaped embossing groove elements. This means that the geometric shape and design of the first raised area, the second raised area, and the third raised area of ​​the vehicle tire according to the invention in the vulcanization mold correspond to the correspondingly complementary shaped first embossing groove element, the second embossing groove element, and the third embossing groove element. Consequently, the respective plateau surfaces of the raised areas of the vehicle tire according to the invention also correspond to the associated embossing base surfaces of the respective embossing groove elements of the vulcanization mold. The same applies to the recess and the groove elements of the vehicle tire according to the invention.The vulcanization mold comprises, correspondingly, the first embossing raised area with the first embossing plateau surface, the second embossing raised area with the second embossing plateau surface, and the third embossing raised area with the third embossing plateau surface. Accordingly, the mean height differences T1, T2, and T3 between the first, second, and third embossing plateau surfaces, as well as between the first, second, and third embossing base surfaces, are the same as the height differences H1, H2, and H3 of the vehicle tire produced according to the inventive method. Those skilled in the art understand that, in this respect, the aforementioned preferred embodiments for the structural elements of the vehicle tire according to the inventive method also apply to the embossing structural elements of the vulcanization mold.

[0056] It can be seen as an advantage of the invention that the structural elements can be applied to the vehicle tires during vulcanization and that no subsequent processing of the tire surface is necessary. In this respect, a further advantage is that the vulcanization mold required for the inventive method can be produced using typical material-removal processes, so it is advantageous to exploit this benefit. Accordingly, a method according to the invention is also preferred in which the vulcanization mold is produced using a material-removal process, preferably by machining with a milling tool.

[0057] It is also revealed that a variety of structural elements are used in the area of ​​at least one tire shoulder and / or at least one tire sidewall of a vehicle tire to improve its aerodynamic properties. wherein the structural elements each comprise a circumferential first elevation with a first plateau surface, a circumferential second elevation surrounding the first elevation with a second plateau surface, and a circumferential third elevation surrounding the second elevation with a third plateau surface, wherein the first elevation surrounds a recess with a first base surface, wherein the second elevation is delimited from the first elevation by a circumferential groove element with a second base surface, wherein the third elevation is delimited from the second elevation by a circumferential groove element with a third base surface, wherein: H1 is the mean height difference between the first plateau surface and the first base surface, H2 is the mean height difference between the second plateau surface and the second base surface, H3 is the mean height difference between the third plateau surface and the third base surface.and wherein, within each structural element, H1, H2, and H3 are distinct from each other.

[0058] The person skilled in the art understands that the invention also discloses a vulcanization mold, preferably for use in a method according to the invention, comprising in an area provided for the formation of a tire shoulder and / or tire sidewall an embossing structure area, wherein the embossing structure area comprises a plurality of embossing structure elements arranged on the surface of the vulcanization mold. wherein the embossing structure elements each comprise a circumferential first embossing groove element with a first embossing base surface, a circumferential second embossing groove element surrounding the first embossing groove element with a second embossing base surface, and a circumferential third embossing groove element surrounding the second embossing groove element with a third embossing base surface, wherein the first embossing groove element surrounds an embossing ridge with a first embossing plateau surface, wherein the second embossing groove element is delimited from the first embossing groove element by a circumferential embossing ridge with a second embossing plateau surface, wherein the third embossing groove element is delimited from the second embossing groove element by a circumferential embossing ridge with a third embossing plateau surface, wherein: T 1 is the mean height difference between the first embossing plateau surface and the first embossing base surface,T2 is the mean height difference between the second embossing plateau surface and the second embossing base surface, T3 is the mean height difference between the third embossing plateau surface and the third embossing base surface, and where T1, T2, and T3 are different from each other within each embossing structure element.

[0059] Preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying figures. These figures show: Fig. 1 a schematic representation of a vehicle tire according to the invention in a preferred embodiment in a top view of a sidewall of the vehicle tire; Fig. 2 a schematic representation of an enlarged section of the vehicle tire according to the invention. Fig. 1Fig. 3 a schematic top view of an exemplary structural element in a preferred embodiment; Fig. 4 a schematic cross-sectional view through the structural element of the Fig. 3 ; and Fig. 5 a schematic cross-sectional representation of one of the Fig. 4 complementary embossing structure element of a vulcanization mold for use in an inventive method for manufacturing a vehicle tire according to the invention.

[0060] Fig. 1Figure 10 schematically shows a vehicle tire 10 according to the invention in a top view of the sidewall 12 of the vehicle tire 10. The vehicle tire 10 according to the invention comprises, in the area of ​​the sidewall 12, two separate structural areas 14a and 14b, which are separated from each other, in particular by marking areas. These structural areas extend in mutually delimited regions along the circumferential direction and along the radial direction of the vehicle tire 10 according to the invention. The structural areas 14a and 14b consist essentially entirely of a plurality of structural elements 16. In the example shown, the structural areas 14a and 14b each comprise more than 150 structural elements 16. Fig. 1 The circular marking indicates the section that is in Fig. 2 is shown enlarged.

[0061] As from the Figs. 1 and 2As can be seen, the structural elements 16 in the two structural areas 14a-b are arranged in a regular pattern and butted against each other, such that the structural elements 16 in structural area 14a-b have a combined area fraction of essentially 100%, based on the area of ​​the respective structural area 14a-b. In the example shown, the structural elements 16 have an element size in the range of approximately 4 to 5.5 mm, with radially inner structural elements 16 having smaller dimensions than radially outer structural elements 16 in order to adapt the shape of the structural areas 14a-b to the curvature of the tire sidewall 12.

[0062] The structural elements 16 show, as in Fig. 2All the structural elements shown exhibit the same mirror-symmetric and rotationally symmetric basic geometric shape and arrangement. Each structural element 16 comprises a first projection 18 surrounding a central recess 30, and a second projection 22 as well as a third projection 26, each separated from the other by groove elements 34a, 34b. Within the structural area 14a-b, the structural elements 16 are arranged such that a group of multiple structural elements 16 is obtained in the structural area 14a-b, in each of which the outer circumferential projection, i.e., the third projections 26, is formed by the same raised structure, which extends as a honeycomb structure on the tire sidewall 12.

[0063] Fig. 3 shows a schematic top view of an exemplary structural element 16 in a preferred embodiment, whereas Fig. 4a cross-sectional view through this structural element 16 along the section axis AA' is shown. The structural element 16 shown exhibits, as shown in the Figs. 1 and 2 The structural elements 16 shown have exactly three circumferential elevations, which are arranged essentially concentrically to each other. In contrast to the structural elements 16 of the Figs. 1 and 2 , which have a hexagonal structure, is in the in Figs. 3 and 4 In the embodiment shown, the structural element 16, and thus all protrusions, recesses and grooves, are formed in a circular shape, the cross-sectional view of which Fig. 4 also on the hexagonal structural elements 16 of the Figs. 1 and 2 is transferable. As shown in the cross-sectional view of the Fig. 4As can be seen, all elevations have a trapezoidal cross-sectional area perpendicular to their centerline, i.e., their circumferential direction. The first elevation 18 has a first plateau surface 20, the second elevation 22 a second plateau surface 24, and the third elevation 26 a third plateau surface 28. Similarly, the recess 30 comprises a first base surface 32, the middle groove element 34a a second base surface 36, and the outer groove element 34b a third base surface 38.

[0064] All plateau surfaces and all base surfaces in the structural element 16 have outer contours that can be transformed into one another by central elongation. Furthermore, in the preferred embodiment shown, neither the web widths of the plateau surfaces nor the mean opening angles of the groove elements 34a-b within the structural element 16 vary. The mean web width of the plateau surfaces transverse to the center line is 0.15 mm in the example shown.

[0065] From the Fig. 4 It is also evident that all elevations have a side wall that forms an angle α of 120° relative to the adjacent ground surface, and thus have a slope of approximately 60° relative to the respective ground surface. As a result, the cross-section of the first elevation 18, the second elevation 22, and the third elevation 26 is in the shape of an isosceles trapezoid. The first ground surface 32, the second ground surface 36, and the third ground surface 38 are at the same height relative to each other and simultaneously lower than the tire surface surrounding the structural area 14a-b (not shown). At the same time, the first plateau surface 20, the second plateau surface 24, and the third plateau surface 28 are at different heights relative to each other, with the third plateau surface 28 being at the same height as the tire surface surrounding the structural area 14a-b (not shown).

[0066] In the example shown, the mean height difference H1 between the first plateau surface 20 and the first bottom surface 32 is approximately 0.2 mm. The mean height difference H2 between the second plateau surface 24 and the second bottom surface 36 is approximately 0.4 mm, and the mean height difference H3 between the third plateau surface 28 and the third bottom surface 38 is approximately 0.6 mm. Because the mean height difference H1 is smaller than the mean height difference H2, which in turn is smaller than the mean height difference H3, a particularly advantageous dimple-like structure results in the oblique top view of the vehicle tire surface.

[0067] Fig. 5 shows a section-by-section cross-sectional view of an exemplary vulcanization mold 40, which is used to produce the structural element 16 of the Fig. 3can be used in a method according to the invention. The vulcanization mold 40 for producing the vehicle tire 10 according to the invention comprises, in the area provided for forming the tire shoulder and / or tire sidewall 12, a stamping structure area with a plurality of stamping structure elements 42, complementary to the structural area 14a-b of the vehicle tire 10. Each stamping structure element 42 comprises – complementary to the structural element 16 – a first stamping base surface 46 of a first stamping groove element 44, a second stamping base surface 50 of a second stamping groove element 48, and a third stamping base surface 54 of a third stamping groove element 52. These correspond with respect to their dimensions to those of the first plateau surface 20, the second plateau surface 24, and the third plateau surface 28 of the structural element 16.Accordingly, the embossing structure element 42 also includes a first embossing plateau surface 56, a second embossing plateau surface 58 and a third embossing plateau surface 60 that are complementary to the first base surface 32, second base surface 36 and third base surface 38.

[0068] As can be seen from a direct comparison of the Figs. 3 and 4 As can be seen, the vulcanization shape 40 in the embossed structure area thus corresponds to the negative of the structural area 14a-b in the vehicle tire 10 according to the invention. Accordingly, the mean height difference T1 between the first embossed plateau surface 56 and the first embossed base surface 46, the first height difference H1 between the first plateau surface 20 and the first base surface 32 of the structural element 16, and the mean height differences T2 and H2 as well as T3 and H3 are equal in magnitude. The in Fig. 5The vulcanization form 40 shown can be advantageously produced in a time- and cost-efficient manner using a material-removing process, for example by means of a milling tool, in particular by means of a graver. Reference symbol list

[0069] 10 Vehicle tire 12 Tire sidewall 14a-b Structure area 16 Structure element 18 First raised area 20 First plateau surface 22 Second raised area 24 Second plateau surface 26 Third raised area 28 Third plateau surface 30 Recess 32 First base surface 34a-b Groove element 36 Second base surface 38 Third base surface 40 Vulcanization form 42 Embossed structure element 44 First embossed groove element 46 First embossed base surface 48 Second embossed groove element 50 Second embossed base surface 52 Third embossed groove element 54 Third embossed base surface 56 First embossed plateau surface 58 Second embossed plateau surface 60 Third embossed plateau surface α Angle A, A' Intersection axis

Claims

1. Vehicle tyre (10), comprising, in the region of at least one tyre shoulder and / or at least one tyre sidewall (12), a structural region (14a, 14b), wherein the structural region (14a-b) comprises a plurality of structural elements (16) arranged on the surface of the vehicle tyre, wherein the structural elements (16) each comprise a circumferential first elevation (18) having a first plateau face (20), a circumferential second elevation (22), which surrounds the first elevation (18) and has a second plateau face (24), and a circumferential third elevation (26), which surrounds the second elevation (22) and has a third plateau face (28), wherein the first elevation (18) surrounds a recess (30) having a first bottom face (32), wherein the second elevation (22) is delimited from the first elevation (18) by a circumferential groove element (34a) having a second bottom face (36), wherein the third elevation (26) is delimited from the second elevation (22) by a circumferential groove element (34b) having a third bottom face (38), wherein: - H1 is the mean height difference between the first plateau face (20) and the first bottom face (32), - H2 is the mean height difference between the second plateau face (24) and the second bottom face (36), - H3 is the mean height difference between the third plateau face (28) and the third bottom face (38), and wherein, within each structural element (16), H1, H2 and H3 are different from one another, wherein at least one structural region (14a-b) extends along the circumferential direction of the vehicle tyre (10), wherein the structural elements (16) in the structural region (14a-b) have different dimensions along the radial direction, wherein the radially inner structural elements (16) are preferably smaller than the radially outer structural elements (16).

2. Vehicle tyre (10) according to Claim 1, wherein the combined area proportion of all of the structural regions (14a-b) on a tyre sidewall (12) or tyre shoulder is 10% or more, preferably 20% or more, particularly preferably 30% or more, with respect to the surface area of the tyre sidewall (12) or tyre shoulder.

3. Vehicle tyre (10) according to either of Claims 1 and 2, wherein at least some of the structural elements (16) are arranged adjacent to one another in at least one structural region (14a-b) so as to obtain, in the structural region (14a-b), an assembly consisting of a plurality of structural elements (16), in each of which the outer circumferential elevation is formed by the same elevated structure.

4. Vehicle tyre (10) according to one of Claims 1 to 3, wherein, within each structural element (16), H1 is smaller than H2, preferably by 20% or more, and / or wherein, within each structural element (16), H2 is smaller than H3, preferably by 10% or more, wherein preferably, within each structural element (16), H1 < H2 < H3.

5. Vehicle tyre (10) according to one of Claims 1 to 4, wherein the first plateau face (20) and / or the second plateau face (24) and / or the third plateau face (28) have / has an outer outline, the shape of which is selected from the group consisting of polygons and ellipses, preferably selected from the group consisting of hexagons, quadrilaterals and circles.

6. Vehicle tyre (10) according to one of Claims 1 to 5, wherein at least some of the structural elements (16) have further circumferential (n)th elevations having further (n)th plateau faces, which surround the (n-1)th elevation, wherein each (n)th elevation of the (n-1)th elevation is delimited by a circumferential groove element having an (n)th bottom face, wherein - Hn is the mean height difference between the (n)th plateau face and the (n)th bottom face.

7. Vehicle tyre (10) according to one of Claims 1 to 6, wherein the first bottom face (32), the second bottom face (36) and the third bottom face (38) are at the same height relative to one another, with respect to the direction orthogonal to the tyre surface.

8. Vehicle tyre (10) according to one of Claims 1 to 7, wherein at least some of the structural elements (16) have an element size in the range from 3 to 8.5 mm, wherein the element size is the largest distance between two points on the outer outline of the plateau face of the outermost elevation.

9. Method for producing a vehicle tyre (10) according to one of Claims 1 to 8, comprising the method steps of: a) producing a non-vulcanized vehicle tyre blank, comprising a vulcanizable rubber compound in at least one component, and b) vulcanizing the non-vulcanized vehicle tyre blank in a vulcanization mould (40) to obtain a vehicle tyre (10), wherein the vulcanisation mould (40) comprises an embossing structural region in a region provided for forming a tyre shoulder and / or tyre sidewall, wherein the embossing structural region comprises a plurality of embossing structural elements (42) arranged on the surface of the vulcanisation mould, wherein the embossing structural elements (42) each comprise a circumferential first embossing groove element (44) having a first embossing bottom face (46), a circumferential second embossing groove element (48), which surrounds the first embossing groove element (44) and has a second embossing bottom face (50), and a circumferential third embossing groove element (52), which surrounds the second embossing groove element (48) and has a third embossing bottom face (54), wherein the first embossing groove element (44) surrounds an embossing elevation having a first embossing plateau face (56), wherein the second embossing groove element (48) is delimited from the first embossing groove element (44) by a circumferential embossing elevation having a second embossing plateau face (58), wherein the third embossing groove element (52) is delimited from the second embossing groove element (48) by a circumferential embossing elevation having a third embossing plateau face (60), wherein: - T1 is the mean height difference between the first embossing plateau face (56) and the first embossing bottom face (46), - T2 is the mean height difference between the second embossing plateau face (58) and the second embossing bottom face (50), - T3 is the mean height difference between the third embossing plateau face (60) and the third embossing bottom face (54), and wherein, within each embossing structural element (40), T1, T2 and T3 are different from one another.