Heating press

Abstract

The invention relates to a heating press (1) for vulcanizing a vehicle tire, wherein the heating mold upper part (2) and the heating mold lower part (3) each have a sidewall region (7) and a tread region (8), wherein the sidewall region (7) and the tread region (8) of the heating mold upper part (2) can be heated with a heat source (11) and the heating mold lower part (3) can be heated with the same heat source (11) or a further heat source (11).

Description

[0001] The invention relates to a heating press for vulcanizing a vehicle tire. The heating press comprises an upper mold part and a lower mold part, wherein the upper mold part and the lower mold part each have sidewall regions and tread regions. The sidewall region and the tread region of the upper mold part and the lower mold part are each heated with the same heat source. The invention further relates to a method for vulcanizing a vehicle tire and to a vehicle tire.

[0002] Heating molds, typically steam-heated ones, are known in which the tread and sidewall areas are heated to the same temperature. It has been shown that this can have a detrimental effect on vehicle tires with known heating molds. When heat is applied to the tread over a period of time, which is necessary for good grip, the sidewall areas experience more heat over a period of time than is optimal for them. They are overheated and exhibit damage to the network or reversion, which leads to increased rolling resistance and accelerated aging.

[0003] Furthermore, heating molds are known that heat the tread area and the sidewall area of ​​the heating mold to different temperatures. This can be achieved with steam-heated heating molds, which are therefore complex in design and thermally inefficient.

[0004] Against this background, the invention is based on the object of designing a heating mold and a method in such a way that the sidewall areas and the tread areas of a vehicle tire experience different heat flows during the heating process, or the sidewall areas are heated more slowly than the tread areas, wherein the structure of the heating press is as simple as possible and can preferably be retrofitted in a simple form to existing heating presses and the heating press has a good thermal efficiency.

[0005] This object is achieved by a heating press according to the features of patent claim 1, as well as a method and a vehicle tire according to the independent claims. The subclaims relate to particularly useful developments of the invention.

[0006] According to the invention, a heating press is provided for vulcanizing a vehicle tire, preferably a two-wheeler tire, in particular a bicycle tire, wherein the upper mold part and the lower mold part each have a sidewall region and a tread region. The sidewall region and the tread region of the upper mold part can be heated with a heat source, and the sidewall region and the tread region of the lower mold part can be heated with the same heat source or a further heat source. The sidewall regions have a thermal insulation layer for contact with a vehicle tire.

[0007] Because the upper and lower mold sections each have a sidewall area and a tread area, which together form, among other things, the entire tread area of ​​a vehicle tire, additional components for shaping the vehicle tire, such as a container with movable segments, are eliminated. This enables a particularly cost-efficient heating press both in production and operation.

[0008] The thermal insulation layers on the sidewall areas reduce the heat flows through the sidewall areas, whereby the sidewall areas of the vehicle tire heat up more slowly and experience high temperatures over a shorter period of time. The sidewall areas are understood to be the areas that adjoin the tread and preferably include the bead area. Different heat flows can be achieved in the tread in relation to the sidewall areas, i.e. a smaller one in the sidewall area and a larger one in the tread area, whereby the complex supply and control of multiple heat flows and / or the use of multiple heat sources for heating the upper or lower part of the heating mold can be dispensed with. A heat source can in particular be a steam generator.

[0009] A preferred embodiment provides that the insulation layer continues to extend over the bead area. This allows for a lower heat flow into the bead area compared to the tread area.

[0010] A further preferred embodiment provides that the insulation layer reduces the heat flow from the heating press into the vehicle tire by at least 15%, preferably at least 25%, more preferably at least 30%, more preferably at least 35%, more preferably at least 40%, more preferably at least 45%, more preferably at least 50%, more preferably at least 55%, more preferably at least 60% and preferably by less than 90%, more preferably by less than 85%, more preferably by less than 80%. It has been shown that a strong reduction in the heat flow of at least 15% leads to advantageously heated sidewall regions. The further the heat flow is reduced, the more advantageously the sidewall regions are heated, whereby it has been shown that an excessive reduction in the heat flow, in particular by more than 90%, leads to underheating of the sidewall regions, which is also disadvantageous for the sidewall regions.

[0011] Another preferred embodiment provides for the insulation layer to be in direct contact with the metal sidewall region. It has been shown that a simple and thus cost-effective structure, as well as a design of the sidewall regions that is particularly resistant to mechanical and thermal stresses, is achieved when the insulation layer is in direct contact with the metal sidewall region.

[0012] A further preferred embodiment provides that the insulation layer is a ceramic coating, in particular an aluminum oxide layer, a titanium oxide layer, a zirconium oxide layer, an yttrium oxide layer, a chromium oxide layer, a calcium oxide layer, a magnesium oxide layer, a zirconium oxide-calcium oxide layer or a zirconium oxide-yttrium oxide layer.

[0013] Ceramic coatings have proven particularly suitable as insulation layers due to their low thermal conductivity and high thermal and mechanical resistance. Furthermore, ceramic coatings have been shown to form a durable bond with metallic hot press components. Furthermore, it has been demonstrated that the ceramic coatings can be produced in a suitable geometry for the specific application.

[0014] A further preferred embodiment provides that the insulation layer has a layer thickness of greater than 60 µm, preferably greater than 120 µm, more preferably greater than 240 µm, more preferably greater than 500 µm, more preferably greater than 800 µm, and more preferably greater than 1200 µm. It has been shown that large layer thicknesses, i.e. at least greater than 60 µm, of the insulation layer are advantageous because they provide sufficiently high thermal insulation. Furthermore, it has been shown that large layer thicknesses are particularly mechanically stable, and a reduction in layer thickness due to wear has less of a negative impact.

[0015] A further preferred embodiment provides that the insulation layer has a Vickers hardness (100) of greater than 500 HV, preferably greater than 800 HV, more preferably greater than 1200 HV, more preferably greater than 1600 HV, and even more preferably greater than 2000 HV. The higher the hardness of the insulation layer, the more resistant the insulation layer is to wear. It has been shown that insulation layers with a Vickers hardness of over 2300 HV have even higher abrasion resistance; however, such hard insulation layers are more likely to chip away from the base material. Therefore, a Vickers hardness of less than 2300 HV is preferred.

[0016] A further preferred embodiment provides that the surface of the insulation layer has an average roughness Ra of greater than 0.2 µm, preferably greater than 0.4 µm, more preferably greater than 0.6 µm and more preferably greater than 1 µm and preferably less than 4 µm, more preferably less than 3 µm, less than 2 µm.

[0017] A further preferred embodiment provides that the sidewall region and the tread region of the upper and lower mold parts are each formed as one piece. Such upper and lower mold parts are particularly cost-effective in production and maintenance. According to the invention, a method for vulcanizing a vehicle tire using a heating press according to the invention is provided, comprising the steps: - Inserting a vehicle tire into the heating press, - Closing the heating press, - Vulcanizing the vehicle tire, - Opening the heating press, - Removing the vulcanized vehicle tire.

[0018] Such a method, carried out with the heating press according to the invention, enables the production of vehicle tires with a particularly suitably heated sidewall area in a particularly simple manner.

[0019] According to the invention, a vehicle tire is provided that is produced using a heating press according to the invention, preferably produced using a method according to the invention. A vehicle tire produced using the heating press according to the invention can be produced particularly cost-efficiently and furthermore has particularly suitably heated sidewall regions, so that the vehicle tire has low rolling resistance and the sidewall regions are particularly resistant to aging.

[0020] The invention is susceptible of numerous embodiments. To further clarify its basic principle, one of these is illustrated in the drawings and will be described below. Fig. 1 a heating press for vulcanizing a vehicle tire with a thermal insulation layer.

[0021] Fig. Figure 1 shows a curing press 1 for vulcanizing a bicycle tire, comprising an upper mold part 2 and a lower mold part 3. The lower mold part 3 is mounted on a lower press plate 4 and is fixed in place. The upper mold part 2 is fixed to an upper press plate 5 and moves vertically together with the plate, driven by a hydraulic cylinder 6.

[0022] The one-piece upper mold part 2 and the one-piece lower mold part 3, also known as mold parts, each have a sidewall region 7 and a tread region 8, which form the vehicle tire sidewall region and the vehicle tire tread region, respectively. The sidewall region 7 has a thermal insulation layer 9 on its surface, which comes into contact with a vehicle tire during vulcanization. This layer is applied to the otherwise steel lower mold part 3.

[0023] The thermal insulation layer 9 merges flush with the tread area 8 and extends from there into the bead area 10. The thermal insulation layer 9 consists of aluminum oxide and has a layer thickness of 750 µm with a hardness of 1200 HV. The surface has a roughness Ra of 1.8 µm.

[0024] If the heating mold upper part 2 and the heating mold lower part 3 are heated by a heat source 11 in the form of a steam generator by means of steam lines 12 and steam chambers 13, the side wall areas 7 heat up in the areas in which they come into contact with the vehicle tires, slowed down by the insulation layer 9.

[0025] A center mechanism 14 is arranged in the center of the heating press 1, which supports a bellows 15 and fills and vents it with steam. List of reference symbols 1 heating press 2 Heating mold upper part 3 Heating mold lower part 4 lower press plate 5 upper press plate 6 hydraulic cylinders 7 Side wall area 8 Tread area 9 thermal insulation layer 10 Bead area 11 Heat source 12 steam line 13 Steam chamber 14 Center mechanism 15 bellows

Claims

[1] Heating press (1) for vulcanizing a vehicle tire, preferably a two-wheel tire, in particular a bicycle tire, wherein the heating press (1) has a heating mold upper part (2) and a heating mold lower part (3), wherein the heating mold upper part (2) and the heating mold lower part (3) each have a sidewall region (7) and a tread region (8), wherein the sidewall region (7) and the tread region (8) of the heating mold upper part (2) can be heated with a heat source (11) and the sidewall region (7) and the tread region (8) of the heating mold lower part (3) can be heated with the same heat source (11) or a further heat source (11), characterized by , that the sidewall regions (7) have a thermal insulation layer (9) for coming into contact with a vehicle tire. [2] Heating press (1) according to claim 1, characterized bythat the thermal insulation layer (9) continues to extend over the bead area (10). [3] Heating press (1) according to claims 1 or 2, characterized by that the thermal insulation layer (9) reduces the heat flow from the heating press (1) into the vehicle tire by at least 15%, preferably at least 25%, further preferably at least 30%, further preferably at least 35%, further preferably at least 40%, further preferably at least 45%, further preferably at least 50%, further preferably at least 55%, further preferably at least 60% and preferably by less than 90%, further preferably by less than 85%, further preferably by less than 80%. [4] Heating press (1) according to one of the preceding claims, characterized by that the thermal insulation layer (9) is in direct contact with the metal side wall area (7). [5] Heating press (1) according to one of the preceding claims, characterized bythat the thermal insulation layer (9) is a ceramic coating, in particular an aluminum oxide layer, a titanium oxide layer, a zirconium oxide layer, an yttrium oxide layer, a chromium oxide layer, a calcium oxide layer, a magnesium oxide layer, a zirconium oxide-calcium oxide layer or a zirconium oxide-yttrium oxide layer. [6] Heating press (1) according to one of the preceding claims, characterized by that the thermal insulation layer (9) has a layer thickness of greater than 60 µm, preferably greater than 120 µm, more preferably greater than 240 µm, more preferably greater than 500 µm, more preferably greater than 800 µm and more preferably greater than 1200 µm. [7] Heating press (1) according to one of the preceding claims, characterized bythat the thermal insulation layer (9) has a hardness according to Vickers hardness (100) of greater than 500 HV, preferably greater than 800 HV, more preferably greater than 1200 HV, more preferably greater than 1600 HV and more preferably greater than 2000 HV and preferably less than 2300 HV. [8] Heating press (1) according to one of the preceding claims, characterized by that the surface of the thermal insulation layer (9) has an average roughness Ra of greater than 0.2 µm, preferably greater than 0.4 µm, more preferably greater than 0.6 µm and more preferably greater than 1 µm and preferably less than 4 µm, more preferably less than 3 µm, less than 2 µm. [9] Heating press (1) according to one of the preceding claims, characterized by that the sidewall area (7) and the tread area (8) of the heating mold upper part (2) and the heating mold lower part (3) are each designed as a single piece. [10] Method for vulcanizing a vehicle tire with a heating press (1) according to one of the preceding claims, comprising the steps: - Inserting a vehicle tire into the heating press (1), - Closing the heating press (1), - Vulcanizing the vehicle tire, - Opening the heating press (1), - Removing the vulcanized vehicle tire. [11] Vehicle tires produced with a heating press (1) according to one of claims 1 to 9, preferably with a method according to claim 10.

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