VEHICLE AIR TIRES

Description

[0001] The invention relates to a vehicle pneumatic tire with a tread having shoulder flanks, sidewalls and bead areas, which tire is vulcanized in a vulcanization mold with several radially movable segments of a segment ring for forming the tread and the shoulder flanks, with sidewall shells for forming the outer sides of the sidewalls and with mold parting lines between the segments and the sidewall shells, wherein the shoulder flanks together with those areas which correspond to the positions of the mold parting lines continuously connect to the outer sides of the sidewalls, so that the shoulder flanks are flush with the outer sides of the sidewalls.

[0002] The invention further relates to a vehicle pneumatic tire, as formed immediately after vulcanization in a vulcanization mold, which vulcanization mold is provided with several radially movable segments of a segment ring for forming the tread with shoulder flanks, with sidewall shells for forming the sidewalls and with mold parting lines between the segments and the sidewall shells, wherein circumferential ribs are formed on the outside of the tire along those areas which correspond to the positions of the mold parting lines, bounded by a radially inner and a radially outer rib flank, and wherein the shoulder flanks are aligned with the outer surfaces located radially inside the ribs, interrupted by the ribs, wherein the rib flanks of the ribs are curved inwards in radial section, preferably in a circular arc shape.

[0003] Vehicle pneumatic tires of the type mentioned above are known, for example, from DE 10 2014 212 346 A1. The vehicle pneumatic tire is vulcanized in a vulcanization mold which forms circumferential ribs along the mold parting lines. These ribs have a V-shaped or dome-shaped cross-section with sharp corners at the shoulders and sidewalls. When the vulcanization mold is closed and the raw tire is vulcanized, rubber material penetrates the area of ​​the mold parting line between the segments that, when the vulcanization mold is closed, rest against the sidewall shells. This material forms short, thin rubber films on the tips of the ribs. The circumferential ribs, along with the rubber films, are completely cut off the finished vulcanized tire before delivery.Cutting off the ribs leaves barely visible narrow circumferential strips on the tire sides with an outer surface that is smoother than that of the subsequent shoulder flanks and sidewalls.

[0004] The vulcanization mold forming the tire according to DE 10 2014 212 346 A1 has recesses with recessed sides on the inside of the mold along the parting line. One set of recesses is located on the tread ring segments, and the other on the respective sidewall shell. The parting line therefore begins at the bottom of these recesses. The ribs thus formed on the pneumatic tire, which are also referred to as trimming ribs, contain a certain volume of rubber and, due to their corners on the outside of the tire, repeatedly cause tears in the rubber material when separating from the sidewall and shoulder material.

[0005] A pneumatic tire for vehicles, as formed immediately after vulcanization in a vulcanization mold and as described above, is known, for example, from DE 11 2019 005 907 T5. This pneumatic tire has circumferential ribs on its outer surface along those areas corresponding to the positions of the mold parting lines. These ribs are bounded by a radially inner and a radially outer rib flank, wherein the shoulder flanks are flush with the outer surfaces located radially inside the ribs, interrupted by the ribs, and the rib flanks are convex inwards in radial section. Viewed in radial section, the rib flanks preferably each extend along a circular arc with a radius of 0.3 mm to 2.0 mm, and the radius of the circular arc of the radially outer rib flank being 0.5 mm to 5.0 mm.

[0006] From EP 4 005 783 A1, which constitutes prior art according to Article 54(3) EPC, another vehicle pneumatic tire of the type mentioned above is known, formed immediately after vulcanization in a vulcanization mold. The radially inwardly curved rib flanks, viewed in radial section, each form a circular arc with a radius of 1.2 to 2.0 times that of the circular arc of the radially inner rib flank. The height of the rib, measured at right angles to the shoulder flank, has a defined ratio to the radii of the rib flanks.

[0007] DE 10 2017 214 556 A1 discloses a vehicle pneumatic tire with a tread having shoulder sections, the outer contour of which each runs along a curve and to which sidewalls adjoin. At the boundary between the shoulder sections and the sidewalls, there is a circular edge that runs along the parting line of the vulcanization mold. The edge is formed between the end of the shoulder section of the tread and a concave, inwardly curved transition curve to the sidewall, such that the sidewall is offset inwards relative to the shoulder section. Such a rib can be cleanly cut off after vulcanization.

[0008] From US patent 10,960,622 B2, a vulcanization mold for a vehicle tire is known, wherein the sidewall shells and / or the segments of the tread ring each comprise a recess adjacent to the mold parting line. Furthermore, grooves are formed in the sidewall shells and the segments of the tread ring, which, when the vulcanization mold is closed, run in alignment across the mold parting line and are intended to improve the venting of the vulcanization mold.

[0009] US Patent 6,123,131 A discloses a commercial vehicle tire with ribbed sidewalls, each having two inwardly curved rib flanks designed to provide good protection and adding little to the tire's weight.

[0010] Sidewall markings and designs are transferred to the sidewalls during the tire vulcanization process via the sidewall shells. Recently, sidewall markings and designs have been preferentially embossed as shallow indentations into the rubber material of the sidewalls. The desired result is a visually uniform and flawless finish on the outer sides of the tires, without protrusions or steps, and while ensuring that sidewall markings and designs can be embossed into the rubber material as indentations with minimal material usage.

[0011] The invention is therefore based on the objective of providing tires with an optically uniform design of the tire sides, especially taking into account low material costs and the possibility of manufacturing the tire with recessed sidewall lettering and / or sidewall designs.

[0012] The problem is solved with a vehicle pneumatic tire in which, radially within the areas corresponding to the positions of the mold parting lines, a section of the sidewall immediately connects, forming a circularly circumferential flat surface with a radial extent of 10.00 mm to 25.00 mm when viewed from the side of the tire, and which transitions tangentially into the outside of a further section of the sidewall which has a 0.50 mm to 1.50 mm thin material overhang and is curved outwards in a circular arc in radial section.

[0013] This design avoids the formation of steps at the transition to the material overlay, which allows for the embossing of recessed sidewall lettering and / or sidewall designs, and simultaneously limits the material required for the overlay to the absolute minimum. Overall, this reduces the tire's rolling resistance and air resistance.

[0014] As regards the pneumatic tire, as it is formed immediately after vulcanization in a vulcanization mold, the task is solved by a section of the sidewall immediately adjoining radially within each of the ribs, which, when viewed from the side, forms a circularly circumferential flat surface with a radial extent of 10.00 mm to 25.00 mm and which transitions tangentially into the outside of a further section of the sidewall formed by a 0.50 mm to 1.50 mm thin material overlay and curved outwards in a circular arc in radial section.

[0015] The trimming ribs can therefore be formed with less material compared to the state of the art according to DE 10 2014 212 346 A1, whereby the curvature of the rib flanks inwards enables a gently rounded transition of the rib flanks into the shoulder flanks and the sidewalls and ensures that no tears occur in the rubber material of the sidewall or shoulder flank of the tire when the ribs are subsequently cut off.

[0016] In the outwardly curved section of the sidewall, sidewall lettering, sidewall designs and the like have been embossed as indentations during the vulcanization of the tire.

[0017] In a preferred embodiment, the vehicle pneumatic tire according to the invention is a commercial vehicle tire in which the further section of the sidewall, which is curved in a circular arc, is based on a circular arc with a radius of 150.00 mm to 200.00 mm. In commercial vehicle tires, the reduced air resistance achievable through material savings and the special design is particularly advantageous.

[0018] In a preferred embodiment, the further section of the side wall, which is curved in a circular arc, extends to or almost to the bead area. Without compromising the uniform design of the side walls, a relatively large area of ​​the side walls can thus be provided with side wall lettering or designs in the form of indentations.

[0019] In the case of pneumatic tires, as formed immediately after vulcanization in a vulcanization mold, it is particularly advantageous if the rib flanks of the ribs transition tangentially into both the shoulder flanks and the outer surfaces of the sidewalls. This allows for a particularly clean and largely residue-free separation of the ribs before delivery of the tires.

[0020] In this context, it is advantageous if the circular arc curvature of the radially outer rib flank is based on a circular arc with a radius that is, in particular, at least 0.20 mm larger than the radius of that circular arc which underlies the circular arc curvature of the radially inner rib flank, wherein the circular arc curvature of the radially outer rib flank is based on a circular arc with a radius of 1.30 mm to 2.50 mm, and wherein the circular arc curvature of the radially inner rib flank is based on a circular arc with a radius of 1.10 mm to 1.50 mm.

[0021] Furthermore, a clean and flawless separation of the ribs is particularly supported by the fact that the ribs have a height of 1.00 mm to 2.50 mm, especially 1.30 mm to 1.70 mm.

[0022] In a preferred embodiment of the vehicle pneumatic tire, as it is formed immediately after vulcanization in a vulcanization mold, the further section of the sidewall, which is curved in a circular arc, is based on a circular arc with a radius of 150.00 mm to 200.00 mm if the tire is a commercial vehicle tire.

[0023] Further features, advantages, and details of the invention will now be described in more detail with reference to the schematic drawing, which illustrates an exemplary embodiment. This drawing shows... Fig. 1 a section of a radial cross-section of a vehicle tire immediately after vulcanization in a vulcanization mold, Fig. 2 detail D from Fig. 1 in enlarged view and Fig. 3 a section of a radial cross-section of a segment of a profile ring and a sidewall shell adjoining it of a vulcanization mold of a vehicle pneumatic tire.

[0024] The section view in Fig. 1 and detail D according to Fig. 2 Figure 1 schematically shows the contour of the outer surface 1a and the contour of the inner surface 1b of a section of a vehicle tire, which is exemplified as a commercial vehicle tire. However, the invention is equally applicable to tires of other types, for example, tires for passenger cars, vans, light trucks, or industrial tires. A portion of a tread 2 with a shoulder 2a, a sidewall 3, and a bead area 4 are shown. The other tire components typically provided are not shown and can be designed in a known manner.

[0025] Immediately after the vulcanization of the tire in a vulcanization mold, a [missing information] is located at the radially inner end of the shoulder 2a on the outer side 1a of the vehicle tire. Fig. 1 and Fig. 2Rib 5, shown with dashed lines and having two pointed converging rib flanks 5a, 5b, which in the vulcanization mold in the area of ​​the mold parting line Ft between a side wall shell and segments of a profile ring, as still shown by the Fig. 3 The position of the mold parting line Ft is described and has been formed. Fig. 1 and Fig. 2indicated by a line. The rib 5 circumferentially surrounds the sidewall 3, and at its tip is a protrusion formed as a thin rubber film 6 during the vulcanization of the tire. The outer surface 1a of the tire is designed in the area around the rib 5 such that the shoulder flank 2a is aligned with a section 3a of the outer surface 1a immediately adjoining the rib 5 in the area of ​​the sidewall 3. The section 3a of the sidewall 3 immediately adjoining the rib 5 is designed as a circular, circumferential, flat surface with a radial extent a 1 of 10.00 mm to 25.00 mm, depending on the tire dimensions and type, when viewed from the side. The section 3a transitions tangentially into a thin layer (thickness d in ) 0.50 mm to 1.50 mm. Fig. 2 ) Material surcharge 9 - opposite the dashed line in Fig. 2- formed and outwards curved in a circular arc with a radius R, further section 3b of the sidewall 3, on which a recessed, therefore embossed, sidewall marking and / or a recessed sidewall design can be formed in a known manner. In a commercial vehicle tire, the radius R is on the order of 150.00 mm to 200.00 mm. The material overhang 9 is located outside the tangential transition and, compared to section 3a, is a thickening of the rubber material in section 3a, having a particularly constant thickness d.

[0026] The rib flanks 5a, 5b are curved inwards in radial section and are therefore concave, in particular as circular arcs extending from the tip of rib 5 to the level of the shoulder flank 2a or section 3a, respectively, and transitioning smoothly, in particular tangentially, into these sections. The circular arc curvature of the radially outer rib flank 5a is based on a circular arc with a radius r1 of 1.30 mm to 2.50 mm, while the circular arc curvature of the radially inner rib flank 5b is based on a circular arc with a radius r2 of 1.10 mm to 1.50 mm, where r2 is at least 0.20 mm smaller than r1. Rib 5 has a height h, which is determined at a right angle to a straight line connecting the shoulder flank 2a with section 3a and is 1.00 mm to 2.50 mm, in particular 1.30 mm to 1.70 mm.The ribs 5 are removed or cut off by hand or automatically with a trimming knife after the vulcanization of the tire and before its delivery, together with the rubber film 6.

[0027] The vehicle pneumatic tire is vulcanized in a vulcanization mold which has a profile ring forming the tread, consisting of a number of radially movable segments and axially movable sidewall shells. Fig. 3Figure 1 schematically shows the course of the inner surface 7a of a sidewall shell 7 and the inner surface 8a of the adjoining segment 8 of the tread ring. In the closed state of the vulcanization mold, a boundary surface 8b of the segments 8 lies tightly against a boundary surface 7b of the sidewall shell 7, forming the mold parting line Ft. In the depicted section, the segment 8 forms the shoulder flank 2a of the pneumatic tire, and the sidewall shell 7 forms sections 3a and 3b on the sidewall 3. At the end on the inside of the mold and along the mold parting line Ft, a recess 5' is formed, which is bounded by two recess flanks 5'a and 5'b, one of which is formed on the segments 8 and the other on the sidewall shell 7.After the recess 5' forms the rib 5 on the tire, the recess flanks 5'a and 5'b are convex, i.e., curved outwards, in particular in a circular arc shape with radii r 1 ' and r 2 ' analogous to the radii r 1 and r 2 and in particular forming tangential transitions to the inner surfaces of the segments 8 and the sidewall shell 7. The recesses 5' have a depth t of 1.00 mm to 2.50 mm, in particular of 1.30 mm to 1.70 mm.

[0028] As a result of this design of the vulcanization mold, a vehicle pneumatic tire vulcanized in this mold has, immediately after vulcanization and removal from the mold, a circumferential rib 5 on each of its sides with film-like projections at its tip. Reference symbol list

[0029] 1a Outer side 1b Inner side 2 Tread strip 2a Shoulder flank 3 Side wall 3a Section 3b Section 4 Bead area 5 Rib 5' Recess 5a, 5b Rib flank 5'a, 5'b Recess flank 6 Rubber film 7 Side wall shell 7a Inner side 7b Boundary surface 8 Segment 8a Inner side 8b Boundary surface 9 Material overhang a 1 radial extent D Detail d Thickness r 1 , r 2 Radius r 1 ', r 2 ' Radius R Radius Ft Form parting line t Depth h Height

Claims

1. Pneumatic vehicle tyre with a tread (2) with shoulder flanks (2a), sidewalls (3) and bead regions (4), which tyre is vulcanized in a vulcanizing mould with a plurality of segments (8) of a segment ring that are arranged movably in the radial direction for forming the tread (2) and the shoulder flanks (2a), with sidewall shells (7) for forming the outer sides of the sidewalls (3) and with mould partitions (Ft) between the segments (8) and the sidewall shells (7), wherein the shoulder flanks (2a) together with those regions that correspond to the positions of the mould partitions (Ft) continuously adjoin the outer sides of the sidewalls (3) such that the shoulder flanks (2a) are in line with the outer sides of the sidewalls (3), characterized in that, radially within the regions that correspond to the positions of the mould partitions (Ft), in each case there directly adjoins a portion (3a) of the sidewall (3) which, when the tyre is viewed from the side, forms a circumferential flat surface running around in the form of a circular ring, with a radial extent (a1) of 10.00 mm to 25.00 mm, and which merges tangentially into the outer side of a further portion (3b) of the sidewall (3) which has a thin amount of extra material (9) of 0.50 mm to 1.50 mm and in radial section is curved outwards in the form of a circular arc.

2. Pneumatic vehicle tyre according to Claim 1, which is a commercial vehicle tyre, characterized in that the further portion (3b) of the sidewall (3) curved in the form of a circular arc is based on a circular arc with a radius (R) of 150.00 mm to 200.00 mm.

3. Pneumatic vehicle tyre according to Claim 1 or 2, characterized in that the further portion (3b) of the sidewall (3) curved in the form of a circular arc extends up to or almost up to the bead region (4).

4. Pneumatic vehicle tyre, as formed immediately after vulcanization in a vulcanizing mould, which vulcanizing mould is provided with a plurality of segments (8) of a segment ring that are arranged movably in the radial direction for forming the tread (2) with shoulder flanks (2a), with sidewall shells (7) for forming the sidewalls (3) and with mould partitions (Ft) between the segments (8) and the sidewall shells (7), wherein, formed on the outer side of the tyre, along those regions that correspond to the positions of the mould partitions (Ft), are ribs (5), which run around in the circumferential direction and are delimited by a radially inner and a radially outer rib flank (5a, 5b), and wherein the shoulder flanks (2a) are in line with the outer sides that are located radially within the ribs (5) and are interrupted by the ribs (5), wherein the rib flanks (5a, 5b) of the ribs (5) are curved inwards in radial section, preferably in the form of a circular arc, characterized in that, radially within the ribs (5), in each case there directly adjoins a portion (3a) of the sidewall (3) which, when the tyre is viewed from the side, forms a circumferential flat surface running around in the form of a circular ring, with a radial extent (a1) of 10.00 mm to 25.00 mm, and which merges tangentially into the outer side of a further portion (3b) of the sidewall (3) which is formed by a thin amount of extra material (9) of 0.50 mm to 1.50 mm and in radial section is curved outwards in the form of a circular arc.

5. Pneumatic vehicle tyre according to Claim 4, characterized in that the rib flanks (5a, 5b) merge tangentially both into the shoulder flanks (2a) and into the outer sides of the sidewalls (3).

6. Pneumatic vehicle tyre according to Claim 4 or 5, characterized in that the curvature of the radially outer rib flank (5a) in the form of a circular arc is based on a circular arc with a radius (r1) which is in particular at least 0.20 mm greater than the radius (r2) of that circular arc which forms the basis for the curvature of the radially inner rib flank (5b) in the form of a circular arc, wherein the curvature of the radially outer rib flank (5a) in the form of a circular arc is based on a circular arc with a radius (r1) which is 1.30 mm to 2.50 mm, and wherein the curvature of the radially inner rib flank (5b) in the form of a circular arc is based on a circular arc with a radius (r2) which is 1.10 mm to 1.50 mm.

7. Pneumatic vehicle tyre according to one of Claims 4 to 6, characterized in that the ribs (5) have a height (h) of 1.00 mm to 2.50 mm, in particular of 1.30 mm to 1.70 mm.

8. Pneumatic vehicle tyre according to one of Claims 4 to 7, which is a commercial vehicle tyre, characterized in that the further portion (3b) of the sidewall (3) curved in the form of a circular arc is based on a circular arc with a radius (R) of 150.00 mm to 200.00 mm.