Patent Publication Number: US-2022219496-A1

Title: Pneumatic Vehicle Tire Having a Hatched Surface

Description:
The invention relates to a pneumatic vehicle tire having sidewalls and having a tread and having at least one hatching area on at least one of the sidewalls and/or on the tread, wherein the hatching area has mutually adjacently arranged hatching elements, wherein each hatching element has a hatching rib. 
     Such hatching areas are generally molded into the tire in the course of the vulcanization of the tire by means of a shape-imparting vulcanization mold which has a negative contour of the hatching area. A structured surface of an already vulcanized tire can however also be achieved by removal, for example by means of engraving, or by an additive process. 
     Such hatching areas are known. On the tire sidewall and/or on the tread, they are used for example to realize a marking. A marking may include images, characters, company names, company logos, designations, areas, etc. The hatching area may be part of the marking and/or may completely or partially surround the latter. 
     The scattering of light on the flanks of the hatching ribs reduces the reflection of the light on the surface of the tire, which changes the brightness effect. In general, surface regions provided with transverse elevations appear darker than substantially smooth surface regions that are free from such elevations. This make it possible to realize a contrast in the inherently monochrome surface of the tire, in particular of the sidewall and/or of the tread. Depictions of markings can thus be made more clearly visible. 
     For example, DE 10 2012 105 864 A1 has disclosed a pneumatic vehicle tire which, on its sidewall, has a multiplicity of hatching ribs for a high-contrast surface design and accentuation of a marking. 
     A disadvantage of such embodiments is that the design options are limited. 
     The problem addressed is therefore that of influencing the contrast effect in even more targeted fashion, and further increasing the contrast effect. It is furthermore sought to allow improved ventilation capability during the production of the tire by means of a vulcanization mold. 
     This is achieved in that each hatching element has short transverse elevations, which cross the hatching rib in crossing regions, wherein the short transverse elevations cross in each case exactly one hatching rib. 
     It has been found that a hatching element with short transverse elevations which cross the hatching rib in crossing regions produces a significantly stronger contrast effect than a hatching rib which is free from such crossing regions or short transverse elevations crossing it. Each short transverse elevation may extend to both sides of the hatching rib. The additional flanks of the short transverse elevations increase the scattering, the multiple reflection and the absorption of light that is incident on the hatching area. In addition, the flanks of the hatching ribs are interrupted by the short transverse elevations, which further increases the contrast. Multiple reflection on hatching elements that run adjacent to one another additionally intensifies the effect. In addition, the short transverse elevations create additional shadow effects which, particularly on the black rubber of the pneumatic vehicle tire, give rise to a clear accentuation of the hatching area in relation to the surrounding surface regions. Since the short transverse elevations each cross exactly one hatching rib, each short transverse elevation also has two free end regions, which cause additional scattering of the light in different directions. 
     By means of the hatching element with short transverse elevations crossing it, the contrast effect can thus be influenced and improved in an even more targeted manner. 
     The connection of the short transverse elevations and the hatching rib in the crossing regions also allows advantageous ventilation of the structure surface during the tire construction process. Furthermore, the short transverse elevations stabilize the hatching elements in the crossing regions, as a result of which the hatching elements are more resistant to scuff marks during use of the tire. 
     One advantageous embodiment is provided in that the hatching area has at least two adjacent hatching elements, the short transverse elevations of which are oriented parallel to one another, and in that the short transverse elevations of one adjacent hatching element are arranged offset, preferably centrally offset, relative to the short transverse elevations of the other adjacent hatching element. 
     Here, “arranged offset” means that the short transverse elevations of one adjacent hatching element, in the elongation thereof, intersect the other adjacent hatching element between two crossing regions. Here, “arranged centrally offset” means that the crossing region comprises at least the center between two crossing regions. 
     The offset arrangement of the short transverse elevations allows a particularly uniform distribution of the short transverse elevations in the case of a close arrangement. 
     It is expedient if all adjacent crossed hatching ribs are designed in this way. 
     One advantageous embodiment is provided in that the hatching ribs of the hatching elements are arranged with a spacing of 0.4 mm to 1.0 mm, preferably of 0.5 mm to 0.7 mm, particularly preferably of 0.55 mm to 0.60 mm. 
     Such a spacing of 0.4 mm to 1.0 mm, preferably of 0.5 mm to 0.7 mm, particularly preferably of 0.55 mm to 0.60 mm, makes an improved contrast effect possible with simultaneously low manufacturing outlay. 
     The spacing may be measured between areas that run perpendicular to the tire surface and along the ridges of the hatching ribs. 
     One advantageous embodiment is provided in that the crossing regions of at least one of the hatching elements are arranged with a spacing of 0.2 mm to 0.5 mm, preferably of 0.25 mm to 0.35 mm. 
     Such a spacing allows a sufficiently close arrangement of the short transverse elevations for an advantageous contrast effect, with simultaneously low manufacturing outlay. The advantages are further intensified if all crossed hatching ribs are designed in this way. The spacings may be measured between the center points of the crossing regions. 
     One advantageous embodiment is provided in that the longitudinal extent direction of at least one of the hatching ribs encloses an angle of 45° to 90°, preferably of 60° to 90°, particularly preferably of 90°, with the respective longitudinal extent direction of the short transverse elevations crossing it. 
     The angle influences the local density distribution on inclined flanks adjacent to crossing regions. In the case of an angle of less than 45°, however, the demolding of the tire is made more difficult. An angle of 60° to 90° allows an improved contrast effect with simultaneously good demoldability. The demoldability is further improved in the case of an angle of 90°. 
     It is also expedient if all short transverse elevations of a hatching element enclose the same angle with the respective hatching rib. This limits the number of directions to be engraved in order to generate the hatching area. 
     The advantages are further intensified if all hatching elements are designed in this way. 
     One advantageous embodiment is provided in that the hatching area has at least two adjacent hatching elements, between the short transverse elevations of which there is a clear spacing of at least 10%, preferably of at least 13%, of the spacing of the hatching ribs of the adjacent hatching elements. 
     The clear spacing is measured perpendicular to the longitudinal extent direction of the hatching elements. The clear spacing may be measured at a height H 3  which corresponds to ⅓ of the mean value of the heights H of the two hatching ribs of the adjacent hatching elements. 
     It has been found that such a clear spacing further improves the demoldability. This also makes it possible to increase the multiple reflection of light on both of the adjacent hatching elements, as a result of which the contrast effect is further increased. 
     One advantageous embodiment is provided in that at least one of the hatching ribs has a height H of 0.1 mm to 0.8 mm, preferably of 0.2 mm to 0.5 mm, particularly preferably of 0.25 mm to 0.35 mm. 
     The height H of a hatching rib may be the height averaged along the longitudinal extent of the hatching rib. Heights may be measured relative to a level that corresponds to a mean level of the entire hatching base of the marking region. Heights may also be measured with respect to a level that corresponds to a base level that is formed, for example, by a part of the outer surface of the pneumatic vehicle tire, in particular a base of a shallow depression formed on the surface of the tire. 
     Mean values generally correspond to the arithmetic mean value. 
     In this way, favourable dimensioning for the benefit of producibility is achieved. It is particularly advantageous if several, preferably all, hatching ribs have a corresponding height H. 
     Furthermore, a good contrast effect can be achieved with such a depth, in particular in conjunction with a spacing of adjacent hatching ribs of 0.4 mm to 1.0 mm, preferably 0.5 mm to 0.7 mm, particularly preferably 0.55 mm to 0.60 mm. 
     One advantageous embodiment is provided in that at least one hatching element is designed such that the hatching rib of the hatching element has mutually opposite flanks which enclose an angle of at least 50°, preferably of 55° to 65°, with one another. 
     Such flank angles exhibit a good contrast effect. A corresponding negative shape of a molding tool such as a vulcanization mold can be created for example by means of laser engraving. The angle may be measured between the crossing regions. It is particularly advantageous if the mutually opposite flanks have such an angle over a height extent which corresponds to at least one quarter of the height H of the hatching rib. 
     The advantage is also or additionally intensified if several, preferably all, hatching ribs are formed in this way. 
     One advantageous embodiment is provided in that at least one of the hatching elements has a hatching rib and/or a short transverse elevation with in each case mutually opposite flanks which enclose an angle of 2° to 10°, preferably of 6° to 8°, with one another. 
     Multiple reflection and thus an improved contrast effect can be achieved with such a steep flank angle. A corresponding negative shape of a molding tool such as a vulcanization mold can be created by means of laser engraving of the molding tool. With regard to the hatching rib, the angle may be measured between two crossing regions. With regard to the short transverse elevation, the angle may be measured outside the crossing region. It is particularly advantageous if the mutually opposite flanks have such an angle over a height extent which corresponds to at least one quarter of the height H of the hatching rib. The advantage is also or additionally intensified if several, preferably all, hatching elements are formed in this way. 
     In one expedient embodiment, the hatching ribs each have mutually opposite flanks that enclose an angle of at least 50° with one another, and the short transverse elevations each have mutually opposite flanks that enclose an angle of 2° to 10°, preferably of 6° to 8°, with one another. 
     In another expedient embodiment, both the hatching ribs and the short transverse elevations each have mutually opposite flanks which enclose an angle of 2° to 10°, preferably of 6° to 8°, with one another. 
     It may also be expedient if the hatching ribs and/or the short transverse elevations have mutually opposite flanks which enclose an angle of 2° to 10°, preferably of 6° to 8°, with one another and have a mean width of 0.08 mm to 0.13 mm, preferably of 0.1 mm. The mean width is the arithmetic mean value of the width measured at different heights. 
     One advantageous embodiment is provided in that the short transverse ribs and/or the hatching ribs of at least two hatching elements, in particular of at least two adjacent hatching elements, differ from one another by at least 30° in terms of the angles enclosed by their flanks. 
     In this way, the hatching area can be further optimized with regard to the conflict of aims of resistance to scuff marks versus contrast. 
     It is expedient if adjacent hatching elements differ in that the angles that mutually opposite flanks of the hatching rib enclose with one another differ from one another by at least 30°. A particularly high flank density can be achieved in this way. 
     One advantageous embodiment is provided in that at least one of the hatching elements has a hatching rib and/or at least one short transverse elevation with a cross section which, in the region of at least one flank, has a convexly curved and/or a linear and/or a concavely curved and/or a stepped and/or a bent and/or a structured region. 
     The cross section runs outside a crossing region perpendicularly with respect to the longitudinal extent direction of the respective short transverse elevation or hatching rib. In this way, the contrast effect can be influenced in even more targeted fashion and the contrast effect can be further increased. The advantage is intensified if several, preferably all, crossed hatching ribs and/or short transverse elevations are formed in this way. 
     It is particularly advantageous if the correspondingly shaped region extends over a height extent which corresponds to at least one quarter of the height H of the hatching rib of the hatching element. 
     The hatching ribs and/or the short transverse elevations may transition into the hatching base at a bend or in curved fashion. 
     The cross section may be symmetrical. 
     The hatching ribs and/or the short transverse elevations of the crossed hatching ribs may have a flattened ridge. The ridge may comprise a plateau with a width of 0.03 mm to 0.06 mm. The ridge may also have irregularities in height which amount to a maximum of 5% of the height H. 
     Irrespective of the embodiment, the hatching area may have a hatching base that separates adjacent crossed hatching ribs and/or adjacent short transverse elevations from one another by means of the hatching base. A substantially flat hatching base is preferred. 
     One advantageous embodiment is provided in that at least one hatching element has short transverse elevations which slope downward continuously from the crossing region to a hatching base. 
     In this way, whilst achieving an advantageous support action of the short transverse elevations, the demoldability is simultaneously further improved. 
     In one preferred embodiment, the hatching area is formed on one of the sidewalls of the pneumatic vehicle tire. 
     In a further preferred embodiment, the hatching area is formed on the tread of the pneumatic vehicle tire. The hatching area may in particular also be applied to groove flanks and/or groove bases of grooves running in the tread, or at the tread outlet, that is to say at the shoulder flanks running outside the ground contact patch to the sidewalls, or on the outer surface of the tread, that is to say on treads that come into contact with the ground. 
    
    
     
       Further features, advantages and details of the invention will now be described in more detail on the basis of the drawing, which schematically shows exemplary embodiments of the invention. In the drawing: 
         FIG. 1  shows a pneumatic vehicle tire  1  having a hatching area; 
         FIG. 2  shows a hatching area; 
         FIG. 3  shows a hatching area; 
         FIG. 4  shows examples of cross sections. 
     
    
    
       FIG. 1  shows a pneumatic vehicle tire  1  with sidewalls  2  and a tread  3  and with at least one hatching area  4  on at least one of the sidewalls  2  and/or on the tread  3 . In the case of an arrangement on the tread  3 , the hatching area may in particular also be applied to groove flanks and/or groove bases of grooves running in the tread  3 , or at the tread outlet, that is to say at the shoulder flanks running outside the ground contact patch to the sidewalls, or on the outer surface of the tread, that is to say on treads that come into contact with the ground. 
     The hatching area  4  has at least two hatching elements  5  running adjacent to one another, each of which has a hatching rib  51  and short transverse elevations  53  crossing this hatching rib in crossing regions  52 , wherein the short transverse elevations  53  each cross exactly one of the hatching ribs  51 . 
     A design variant of such a hatching area  4  is shown in  FIG. 2 . The illustrated sectional view of the hatching area  4  has at least two adjacent hatching elements  5 , the short transverse elevations  53  of which are oriented parallel to one another. The short transverse elevations  53  of one adjacent hatching element  5  are offset, preferably centrally offset, relative to the short transverse elevations  53  of the other adjacent hatching element  5 . 
     The short transverse elevations  53  of the crossed hatching ribs  5 , in the elongation  6  thereof, intersect the respectively adjacent hatching element  5  between two crossing regions  52 . In the embodiment shown, the respective intersection region  7  comprises at least the center between two crossing regions  52 . 
     The spacing  8  between the adjacent hatching elements  5  is 0.4 mm to 1.0 mm, preferably 0.5 mm to 0.7 mm, particularly preferably 0.55 mm to 0.60 mm. The spacing  8  may be measured between areas  24  which run perpendicular to the tire surface and along the ridges  18  of the adjacent hatching ribs  51 . 
     The crossing regions  51  of the crossed hatching ribs  5  may be arranged with a spacing  9  of 0.2 mm to 0.5 mm, preferably of 0.25 mm to 0.35 mm. The spacing  9  may be measured between the center points of the crossing regions  51 . In the example illustrated, all crossing regions  51  have approximately the same spacing  9 . 
     A longitudinal extent direction  10  of the hatching elements  51  encloses in each case an angle  11  of 45° to 90°, preferably of 60° to 90°, particularly preferably of 90°, with a respective longitudinal extent direction  12  of the short transverse elevations  53  crossing them. An angle  11  of approximately 90° is illustrated in each case. 
     A clear spacing  13  between the short transverse elevations  53  of adjacent crossed hatching ribs  5  may be at least 10%, preferably at least 13%, of the spacing  8  of the adjacent hatching elements  5 . The clear spacing  13  is measured perpendicular to the longitudinal extent direction  10  of the hatching elements  51 . The clear spacing is measured at a height H 3 , which may be ⅓ of the mean value of the heights H of the hatching ribs  51  of the two adjacent hatching elements  5 . 
     The hatching ribs  51  have a height H of 0.1 mm to 0.8 mm, preferably of 0.2 mm to 0.5 mm, particularly preferably of 0.25 mm to 0.35 mm, wherein the height H is averaged along the longitudinal extent of the respective hatching rib  51 . The height H may be measured relative to a level  20  which corresponds to a mean level of a hatching base  19 . The level  20  may also correspond to a base level that is formed, for example, by a part of the outer surface of the pneumatic vehicle tire, in particular a base of a shallow depression formed on the surface of the tire. 
     The hatching ribs  51  each have mutually opposite flanks  14  which enclose an angle  15  of at least 50°, preferably of 55° to 65°, with one another. The short transverse elevations  53  each have mutually opposite flanks  14  which enclose an angle  15  of 2° to 10°, preferably of 6° to 8°, with one another. It is particularly advantageous if the mutually opposite flanks have such a respective angle over a height extent which corresponds to at least one quarter of the height H of the hatching rib. 
     It is however also possible for both the hatching ribs  51  and the short transverse elevations  53  to each have mutually opposite flanks  14  which enclose an angle  15  of 2° to 10°, preferably of 6° to 8°, with one another. 
     The illustrated hatching ribs  51  and/or the short transverse elevations  53  have a cross section which, in the region of at least one flank, has a region  16  which runs linearly. As shown, this may transition into the hatching base  19  at a bend  17  or else in a curved manner. 
     The hatching ribs  51  and/or the short transverse elevations  53  of the crossed hatching ribs  5  may have a flattened ridge  18 . The ridge may comprise a plateau with a width of 0.03 mm to 0.06 mm. The ridge  18  may also have irregularities in height which amount to a maximum of 5% of the maximum height difference of the hatching area. 
     The hatching area  4  may have a hatching base  19  which separates adjacent hatching elements  5  and/or adjacent short transverse elevations  53  from one another. 
       FIG. 3  shows a further exemplary embodiment according to the invention. It differs from the exemplary embodiment shown in  FIG. 2  at least in that the short transverse elevations  53  slope downward continuously from the crossing region  52  to the hatching base  19 . Furthermore, the flanks  14  of the hatching ribs  51  and of the short transverse elevations  53  transition into the hatching base  19  in a curve. Independently of this, the exemplary embodiments also differ by the fact that the hatching ribs  51  of at least two hatching elements  5 , in particular of at least two adjacent hatching elements  5 , differ from one another by at least 30° in terms of the angles  15 ,  15 ′ enclosed by their flanks  14 . The angle  15  may be 2° to 10°, preferably 6° to 8°, and the angle  15 ′ may be at least 50°. 
       FIGS. 4 a  to 4 g    show examples of cross sections of the hatching ribs  51  and/or of the short transverse elevations  53  of a hatching element. The cross section runs in each case outside a crossing region  52  perpendicularly with respect to the longitudinal extent direction of the respective short transverse elevation  53  or hatching rib  51 . The cross sections are suitable for the hatching areas  4  illustrated in  FIGS. 2 and 3 . Without restricting the general nature, the cross sections illustrated are symmetrical. 
       FIG. 4 a    shows a cross section which has a linearly running region  16  in the region of the flanks  14 . The flanks  14  lie opposite one another and may enclose an angle  15  of at least 50°, preferably of 55° to 65°, with one another. The flanks  14  transition into the flat hatching base  19  at a bend. 
       FIG. 4 b    shows a corresponding cross section, wherein the flanks  14  enclose an angle  15  of 2° to 10°, preferably of 6° to 8°, with one another. 
       FIG. 4 c    shows by way of example that, irrespective of the exact design of the cross section, the flanks  14  may also transition into the hatching base  19  with a curvature. 
       FIG. 4 d    shows a cross section which has a convexly curved region  16  in the region of the flanks  14 .  FIG. 4 e    shows a cross section which has a stepped region  16  in the region of the flanks  14 . 
       FIG. 4 f    shows a cross section which has a structured region  16  in the region of the flanks  14 .  FIG. 4 g    shows a cross section which has a concavely curved region  16  in the region of the flanks  14 . 
     In all of  FIGS. 4 a  to 4 g   , the correspondingly shaped region  16  may extend over at least one quarter of the height H of the hatching rib of the corresponding hatching element. 
     LIST OF REFERENCE SIGNS 
     
         
           1  Pneumatic vehicle tire 
           2  Sidewall 
           3  Tread 
           4  Hatching area 
           5  Crossed hatching rib 
           51  Hatching rib 
           52  Crossing region 
           53  Short transverse elevation 
           6  Elongation 
           7  Intersection point 
           8  Spacing of hatching ribs 
           9  Spacing of crossing regions 
           10  Longitudinal extent direction of a hatching rib 
           11  Angle 
           12  Longitudinal extent direction of a short transverse elevation 
           13  Clear spacing 
           14  Mutually opposite flanks 
           15  Angle 
           15 ′ Angle 
           16  Region 
           17  Bent region 
           18  Ridge 
           19  Hatching base 
           20  Level 
           24  Area 
         H Height of a hatching rib 
         H 3  Height