Vulcanization mould and vehicle tyre vulcanized in the mould

Abstract

A vulcanization mould for shaping and vulcanizing vehicle tyres, which comprises mould parts for forming a tread of the tyre, a pair of mutually axially opposite sidewall shells (1, 2), a pair of mutually axially opposite bead rings (3a, 3b) for moulding the bead regions of the tyre that come into contact with a rim, and an annularly encircling insert (5) in at least one sidewall shell (1), the insert being inserted exchangeably in a recess of the sidewall shell (1) and having an inner surface (6) which faces towards the mould cavity and which, together with the inner side of the sidewall shell, forms a base surface and moulds the respective sidewall and the associated bead region of the vehicle tyre. The insert (5) is inserted in the sidewall shell (1) so that it directly adjoins the bead ring (3a), the inner surface (6) of the insert (5) taking up 10% to 40% of the base surface (1a) and being covered by a PTFE layer (5a).

Description

[0001] Description

[0002] Vulcanization form and vulcanized vehicle tire in this

[0003] The invention relates to a vulcanization mold for molding and vulcanizing vehicle tires with molded parts for forming a tread of the tire, a pair of axially opposite sidewall shells, a pair of axially opposite bead rings for molding the bead regions of the tire that come into contact with a rim, and with a circular ring-shaped insert in at least one sidewall shell, which insert is replaceably inserted into a molding of the sidewall shell and has an inner surface facing the mold cavity, which together with the inner side of the sidewall shell forms a base surface and shapes the relevant sidewall and the associated bead region of the vehicle tire.

[0004] Such a vulcanization mold is known, for example, from EP 2 162 278 B1. On the inner sides of each sidewall shell, an annular groove is formed, into which an annular insert is removably inserted. The annular insert's inner surface has graphic markings for imprinting on the tire sidewall and protrudes beyond the inner sides of the sidewall shells. This is intended to improve the tire molding and vulcanization process with a special focus on creating fundamental or decorative motifs on the sidewall. In particular, it should be possible to create different decorative motifs on the tire sidewall using one and the same vulcanization mold.

[0005] EP 1 382 426 B1 discloses a tire vulcanization mold with sidewall shells, wherein at least one of the two sidewall shells is provided with an inner surface that has a surface finish of less than 0.381 microns, particularly through chrome plating. The tire vulcanized in the mold therefore has at least one sidewall with a gloss measurement value greater than 10, measured using a 60° gloss measurement per ASTM D523-89. The sidewall is therefore said to have a surface layer that inhibits the migration of antioxidants from the rubber material and has a glossy black appearance.

[0006] The invention is based on the object of imparting a particularly shiny black appearance to a partial area on at least one sidewall of the vulcanized tire using a vulcanization mold of the type mentioned at the outset, wherein a conventional sidewall design with inscriptions, decorative elements, ornaments, logos and the like can be retained on other areas of the sidewall.

[0007] The object is achieved according to the invention in that the insert is inserted into the side wall shell directly adjacent to the bead ring, wherein the inner surface of the insert occupies 10% to 40% of the base area and is covered with a PTFE layer.

[0008] The insert, which is covered with PTFE on its inner surface, creates a smooth, shiny, and therefore jet-black circular ring on the sidewall directly adjacent to the bead area during tire vulcanization. Its appearance clearly distinguishes it from the rest of the sidewall. This ring is located in a prominent position on the sidewall, but leaves plenty of space outside for the usual sidewall design, including lettering, decorative elements, and the like. Furthermore, the insert is interchangeable, allowing it to be easily replaced after several vulcanization cycles.

[0009] In a preferred embodiment, the inner surface of the insert occupies up to 30%, preferably up to 20%, of the base area. This creates a subtle yet clearly visible shiny circular ring on the outer surface of the sidewall of the tire vulcanized in this vulcanization mold, and sufficient space remains for the formation of decorations, lettering, and the like on the remaining area of ​​the sidewall.

[0010] The PTFE layer on the inner surface of the insert preferably has a thickness of 0.005 mm to 0.10 mm, in particular 0.02 mm to 0.04 mm. A PTFE layer of this thickness allows for a large number of vulcanization processes without damage. A durable and thin PTFE layer is, for example, a layer of PTFE formed by heat treatment and sprayed on.

[0011] In this design, the PTFE layer is advantageously located on a polished or smoothed surface of the insert, so that the circular ring formed on the tire has a particularly high degree of gloss.

[0012] Striking light / shadow effects can be created by placing the PTFE layer on an overall structured inner surface or in certain sections or on surface elements of the structured inner surface of the insert.

[0013] In a particularly advantageous embodiment in this regard, the structure consists of a plurality of ribs which run in particular parallel to one another and which have a height of 0.10 mm to 0.80 mm, in particular 0.20 mm to 0.50 mm, at their highest point.

[0014] A further particularly advantageous embodiment is one in which the structure consists of ribs having rib sections running parallel to one another in a zigzag pattern, wherein the rib sections each have an extension length of 0.20 mm to 0.40 mm, in particular 0.25 mm to 0.30 mm, and wherein the ribs have lateral rib flanks which each run at an angle of up to 10°, in particular 2° to 10°, to a perpendicular to the inner surface. In an alternative embodiment of the vulcanization mold, the PTFE layer is formed by a PTFE strip attached to the insert. In order to be able to detachably attach the PTFE strip to the insert, in particular from the rear side thereof, the PTFE strip has a certain thickness, for example in the order of magnitude of 5.00 mm to 10.00 mm.

[0015] In a further preferred embodiment, the PTE layer is formed by a PTFE strip connected to an annular intermediate part that is releasably attached, in particular screwed, to the insert. The PTFE strip can be bonded to the intermediate part by adhesive.

[0016] The invention further relates to a vehicle tire, in particular a pneumatic vehicle tire, having sidewalls and bead regions, which has been vulcanized in a vulcanization mold according to one or more of claims 1 to 7. On at least one sidewall, immediately adjacent to the bead region, a circumferential circular ring is formed, which has a higher degree of gloss than the rubber materials of the remaining sidewall and the bead region.

[0017] Further features, advantages and details of the invention will now be described in more detail with reference to the schematic drawing, which shows an embodiment.

[0018] Fig. 1 a partial section of a tire vulcanization mold in closed state,

[0019] Fig. 2 is a schematic side view of a tire vulcanized in this vulcanization mold.

[0020] Fig. 1 schematically shows components of a conventional vulcanization mold for a pneumatic vehicle tire, for example, for a passenger car. Only components in one half of the vulcanization mold are shown. The vulcanization mold is located within a heating press, the components of which are not shown. This press typically has an upper press section and a lower press section, as well as mechanisms for positioning the tire to be vulcanized, for operating the vulcanization mold, for introducing the heating medium, and for removing the fully vulcanized tire.

[0021] Fig. 1 shows a lower sidewall shell 1 of the vulcanization mold, which forms one sidewall of the tire, and an upper sidewall shell 2, which forms the second sidewall of the tire, a lower bead ring 3a and an upper bead ring 3b and a mold segment 4 of a conventional segment ring, which consists, for example, of six to eight ring-shaped mold segments in total. Of the sidewall shells 1, 2 and the bead rings 3a, 3b, only one half can be seen in the section according to Fig. 1. The upper sidewall shell 2, together with the upper bead ring 3b, is arranged, for example, on a heating plate (not shown), and can be removed to open and close the vulcanization mold.The mold segments 4 of the segment ring are provided on the inside with profile inserts (not shown), which form a profiled tread of the tire (not shown) and can be moved apart and together radially to open and close the vulcanization mold.

[0022] The bead rings 3a, 3b are known to form those areas of the pneumatic vehicle tire that come into contact with the rim during mounting of the tire. The inner sides of the sidewall shells 1, 2 contain the structures that cause decorations, ornaments, logos, lettering, and the like to be formed on the tire's sidewalls. Between the bead ring 3a, 3b and the mold segments intended for forming the tread, there is a base surface 1a, 2a that follows the curvature or inner contour, from which the aforementioned structures are formed as elevations or depressions. Fig. 1 shows only the base surfaces 1a, 2a without such structures.

[0023] In the illustrated embodiment, a circular insert 5 is inserted into the lower sidewall shell 1, directly adjacent to the bead ring 3a. The insert 5 is inserted into a correspondingly milled recess on the sidewall shell 1 before the bead ring 3a is positioned and is secured by screws from the outside of the sidewall shell 1 in a removable or replaceable manner. The bead ring 3a is then positioned and also secured to the lower sidewall shell 1 by screws.

[0024] The insert 5, which is in the lower side wall shell 1 and is ring-shaped, has a circular inner surface 6 facing the mold cavity and defining the latter, which preferably fits flush with the immediately adjacent areas of the inner sides of the side wall shell 1 and the bead ring 3a. In an alternative embodiment, the insert

[0025] 5 over the immediately adjacent areas of the inner sides of the sidewall shell 1 and the bead ring 3a by in particular 0.50 mm to 2.00 mm and therefore forms a corresponding annular circumferential depression on the sidewall of the tire.

[0026] The insert 5 is preferably designed such that its annular inner surface

[0027] 6 10% to 40%, in particular 30%, preferably up to 20%, of the base surface 1a present between the bead ring 3a and the shaped segments 4 of the segment ring, consisting of the inner surface 6 and the remaining inner side of the side wall shell 1 and in particular uniformly continuous.

[0028] In a preferred embodiment, the insert 5 is manufactured as a turned part made of steel and sprayed on its surface, which subsequently forms the inner surface 6, with a commercially available PTFE (polytetrafluoroethylene) coating spray, a so-called spray & bake PTFE. The sprayed-on PTFE is cured in a heat treatment and then forms a 0.005 mm to 0.10 mm, in particular 0.02 mm to 0.04 mm, thin and strong PTFE layer 5a. Such a PTFE spray is available, for example, under the name Teflon™ Coating Spray from Toefco Engineered Coating Systems, Inc., see (accessed on July 12, 2023). Insert 5 is then installed into sidewall shell 1. The relevant surface of insert 5 can be polished or smoothed before spraying. In an alternative design, a PTFE band of a thickness suitable for screwing is attached to insert 5 in a circular ring, or a separate circular ring-shaped intermediate part, e.g., made of metal, with a PTFE band as a support is manufactured and attached to insert 5, in particular screwed to it.

[0029] Fig. 2 shows a side view of a pneumatic vehicle tire vulcanized in the vulcanization mold, with a sidewall 7 and a bead area 8. The insert 5 has formed a smooth and shiny circular ring 9 on the sidewall 7 of the tire, which appears darker than the surrounding rubber material and which directly adjoins the bead area 8, so that this circular ring 9 directly adjoins the rim when the tire is mounted on a rim.

[0030] In vehicle tires intended for multi-track motor vehicles, such a circular ring 9 is formed on at least one sidewall; in tires with a specific mounting position, it is formed on the sidewall that faces the outside of the vehicle when the tire is mounted. Alternatively, during tire mounting, care can be taken to ensure that the sidewall 7 provided with the circular ring 9 is located on the outside. Furthermore, it is possible to install inserts on both sidewall shells 1, 2, as described, and to form circular rings 9 on both sidewalls 7.

[0031] In a further possible embodiment, the insert 5 has a structured inner surface, created in particular by laser engraving. In one possible embodiment, the inner surface is uniformly structured overall or alternatively in certain sections or on surface elements. The structure consists, for example, of ribs running parallel to one another or essentially parallel to one another, having successive rib sections in a zigzag shape and forming a hatching, wherein the rib sections each have an extension length of 0.20 mm to 0.40 mm, in particular 0.25 mm to 0.30 mm. The ribs have lateral rib flanks, which each run at an angle of up to 10°, in particular 2° to 10°, to a perpendicular to the inner surface. At their highest point, the ribs have a height of 0.10 mm to 0.80 mm, in particular 0.20 mm to 0.50 mm.An embodiment of such a structure is known, for example, from DE 10 2021 212 509 A1. In this structure, a free-ending additional rib branches off from the same side of the hatched ribs and from the inner corner areas.

[0032] List of reference symbols

[0033] 1 lower side wall shell

[0034] 2 upper side wall shell

[0035] 1a, 2a base area

[0036] 3a, 3b bead ring 4 mold segment

[0037] 5 Use

[0038] 5a PTFE layer

[0039] 6 inner surface

[0040] 7 Sidewall 8 Bead area

[0041] 9 circular ring

Claims

Patent claims 1. Vulcanization mold for molding and vulcanizing vehicle tires, comprising molded parts for forming a tire tread, a pair of axially opposed sidewall shells (1, 2), a pair of axially opposed bead rings (3a, 3b) for molding the bead regions of the tire that come into contact with a rim, and a circular insert (5) in at least one sidewall shell (1), which insert is replaceably inserted into a recess in the sidewall shell (1) and has an inner surface (6) facing the mold cavity, which, together with the inner surface of the sidewall shell (1), forms a base surface (1a) and forms the respective sidewall and the associated bead region of the vehicle tire, characterized in that the insert (5) is inserted into the sidewall shell (1) directly adjacent to the bead ring (3a).wherein the inner surface (6) of the insert (5) occupies 10% to 40% of the base surface (1a) and is covered with a PTFE layer (5a).

2. Vulcanization mold according to claim 1, characterized in that the inner surface (6) of the insert (5) occupies up to 30%, preferably up to 20%, of the base surface (1a).

3. Vulcanization mold according to claim 1 or 2, characterized in that the PTFE layer (5a) located on the inner surface (6) of the insert (5) has a thickness of 0.005 mm to 0.10 mm, in particular of 0.02 mm to 0.04 mm.

4. Vulcanization mold according to claim 1 to 3, characterized in that the PTFE layer (5a) is the layer of a sprayed-on PTFE formed by heat treatment.

5. Vulcanization mold according to claim 3 or 4, characterized in that the PTFE layer (5a) is located on a polished or smoothed inner surface (6) of the insert (5).

6. Vulcanization mold according to claim 3 or 4, characterized in that the PTFE layer (5a) is located on an overall structured inner surface or in certain sections or on surface elements structured inner surface of the insert (5).

7. Vulcanization mold according to claim 6, characterized in that the structure consists of a plurality of ribs, in particular running parallel to one another, which have a height of 0.10 mm to 0.80 mm, in particular 0.20 mm to 0.50 mm, at their highest point.

8. Vulcanization mold according to claim 6 or 7, characterized in that the structure consists of ribs running parallel to one another and having successive rib sections in a zigzag shape, wherein the rib sections each have an extension length of 0.20 mm to 0.40 mm, in particular 0.25 mm to 0.30 mm, and wherein the ribs have lateral rib flanks which each run at an angle of up to 10°, in particular from 2° to 10°, to a perpendicular to the inner surface, 9. Vulcanization mold according to one of claims 1 to 3, characterized in that the PTFE layer is formed by a PTFE tape attached to the insert (5).

10. Vulcanization mold according to one of claims 1 to 3, characterized in that the PTFE layer is formed by a PTFE band which is connected to an annular intermediate part which is detachably fastened to the insert (5).

11. Vehicle tires, in particular pneumatic vehicle tires, with side walls (7) and bead regions (8), which has been vulcanized in a vulcanization mold according to one or more of claims 1 to 10, characterized in that on at least one side wall (7) immediately adjacent to the bead region (8) there is formed a circumferential circular ring (9) having a higher degree of gloss than the rubber materials of the remaining side wall (7) and the bead region (8).

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