Heating press for vulcanizing a vehicle tyre

Abstract

The invention relates to a heating press (1) for vulcanizing a vehicle tyre, having a heating-press upper part (2) and a heating-press lower part (3), wherein a container (26) having a heated upper sidewall shell (5) and heated profile segments (5) is provided on the heating-press upper part (3). The heating-press lower part (3) has a heated lower sidewall shell (6). The heating-press upper part (2) is movably mounted with respect to the heating-press lower part (3), wherein the heating-press upper part (2), the container (26) and the heating-press lower part (3) are connected in such a way that moving the heating-press upper part (2) towards the heating-press lower part (3) causes the profile segments (4) to come into contact with one another. The heating press (1) has a central mechanism (13) with gas outlet openings for filling a green tyre with a heating medium.

Description

[0001] Description

[0002] Heating press for vulcanizing a vehicle tire

[0003] The invention relates to a heating press for vulcanizing a vehicle tire, comprising a heating press upper part and a heating press lower part. A container having a heated upper sidewall shell and heated profile segments is arranged on the heating press upper part. The heating press lower part has a heated lower sidewall shell. The heating press upper part is mounted so that it can move relative to the heating press lower part, and the heating press upper part, the container, and the heating press lower part are connected in such a way that the profile segments come into contact with one another when the heating press upper part approaches the heating press lower part. The heating press has a central mechanism with gas outlet openings for filling a green tire with a heating medium. The invention further relates to a method for operating such a heating press.

[0004] Conventional curing presses require a lot of energy to vulcanize vehicle tires. A significant portion of this energy is released into the environment in the form of heat.

[0005] Against this background, the object of the invention is to design a heating press and a method in such a way that low energy consumption is enabled when vulcanizing vehicle tires.

[0006] This object is achieved by a heating press according to the features of patent claim 1 and a method according to the independent claim. The subclaims relate to particularly useful developments of the invention.

[0007] According to the invention, a heating press for vulcanizing a vehicle tire is provided, comprising an upper heating press part and a lower heating press part. A container having a heated upper sidewall shell and heated profile segments is arranged on the upper heating press part. The lower heating press part has a heated lower sidewall shell. The upper heating press part is mounted so that it can be moved relative to the lower heating press part. The upper heating press part, the container, and the lower heating press part are connected in such a way that the profile segments come into contact with one another when the upper heating press part approaches the lower heating press part. The heating press has a central mechanism with gas outlet openings for filling a green tire with a heating medium.

[0008] Seals are arranged on the heating press upper part and / or on the heating press lower part to seal the area enclosed by the heating press upper part and by the heating press lower part from the environment, wherein the heating press upper part and / or the heating press lower part has an opening for applying a negative pressure in the enclosed area. The profile segments and / or the upper side wall shell and / or the lower side wall shell are electrically heated by means of at least one heating element, wherein the at least one heating element is in contact with the profile segments and / or the upper side wall shell and / or the lower side wall shell directly or by means of a thermal conductor.

[0009] The center mechanism can be configured to directly fill a green tire with a heating medium or to fill it using a bellows. Electrical heating refers to heating by means of an electric current flow, which also includes an induced current flow.

[0010] The seals on the upper and / or lower parts of the heating press enable the area enclosed by the upper and lower parts of the heating press to be sealed from the environment. A vacuum pump, which is preferably a component of the heating press and is connected to an opening in the upper and / or lower parts of the heating press, can create a vacuum in the enclosed area. This eliminates the need for valves in the tread segments, which are necessary in conventional heating presses for venting the tire heating mold. The expansion of these valves requires a minimum material thickness for the tread segments. By eliminating the valves, the tread segments can be made with a thinner material, allowing the heating elements to be positioned closer together and with lower thermal resistance on the vehicle tires to be vulcanized.Furthermore, the thermal mass of the profile segments is reduced.

[0011] Due to the very low thermal resistance with which the heating elements are connected to the tread segments or sidewall shells, a large portion of the heat energy released by the heating elements in the heating press is directed into the vehicle tire. The other areas of the upper and lower sections of the heating press heat up less, so less energy is required to heat the heating press. Furthermore, due to the lower temperatures on its surfaces, the heating press releases less energy into the environment.

[0012] A preferred embodiment provides that the heating element is a heating cartridge, in particular a helical tube heating cartridge, or a heating foil.

[0013] A further preferred embodiment provides that the at least one heating element is mounted so as to be separable from the profile segments and / or at least one of the sidewall shells, wherein the profile segments and / or at least one of the sidewall shells is preferably separable from the at least one heating element, wherein the at least one heating element is mounted on the upper part of the heating press or on the lower part of the heating press. A separable mounting of the heating elements from the profile segments and the sidewall shells is understood to mean a mounting that preferably enables immediate manual removal of the heating elements. Preferably, the profile segments and sidewall shells can be removed from the heating press, wherein the heating elements remain mounted in the heating press. A simple and time-consuming change of profile segments and sidewall shells is made possible.The heating elements can be used for various profile segments and sidewall shells. A further preferred embodiment provides that the profile segments and / or at least one sidewall shell have at least two, preferably three, and more preferably four heating elements. It has been shown that, particularly when using heating cartridges, a plurality of heating elements per profile segment or per sidewall shell is advantageous for heat distribution on the vehicle tire.

[0014] A further preferred embodiment provides for a temperature sensor to be arranged on at least one heating element and / or in at least one profile segment and / or in at least one side shell. A temperature sensor arranged in this way allows the heating power to be adapted to the prevailing temperature, thereby enabling an improved temperature profile in the vehicle tire.

[0015] A further preferred embodiment provides for the thermal conductor to be a conductive foil, in particular a compressible conductive foil, or a conductive paste. It has been found that conductive foils, in particular compressible conductive foils, are suitable for ensuring efficient, low-resistance, and reliable reproducible heat flow transfer. Conductive pastes also enable efficient and reproducible heat flow transfer.

[0016] A material is thermally conductive and accordingly a thermal conductor if the thermal conductivity of the material is significantly higher than the thermal conductivity of air, i.e. higher than 0.05 W / (m*K), preferably higher than 0.1 W / (m*K) and more preferably higher than 0.2 W / (m*K).

[0017] A material is more compressible if its initial volume can be reduced by 10%, preferably by 30%, more preferably by 50%, and most preferably by 70%, without damage during the assembly of profile segments or side wall shells. Damage-free means that the material, in the compressed state and after compression, can repeatedly perform its heat transfer function without relevant restrictions. A further preferred embodiment provides that the thermal conductor comprises graphite or a plastic, in particular silicone, or consists of graphite or a plastic, in particular silicone, and is preferably a conductive foil. It has been shown that the materials mentioned have suitable thermal conductivity and mechanical properties, so that efficient heat transfer is ensured in a reliably reproducible manner.

[0018] A further preferred embodiment provides that the heating elements are thermally decoupled, in particular by means of a gap and / or insulation materials, preferably fiber-reinforced materials, particularly preferably glass-fiber-reinforced plastics, from at least one profile segment and / or at least one container. Thermally decoupling the heating elements from segment rings or containers leads to a reduction in the heat flow into the segment rings and containers, thereby further reducing heat loss to the environment.

[0019] A further preferred embodiment provides that the insulation materials have a heat transfer coefficient of less than 0.5 W / (m*K), preferably less than 0.4 W / (m*K), more preferably less than 0.3 W / (m*K), and even more preferably less than 0.28 W / (m*K). The space available for insulation is limited, so it has been found that insulation materials with particularly low thermal conductivity are particularly advantageous.

[0020] A further preferred embodiment provides that the profile segments are thermally decoupled from the sidewall shells, in particular by means of a gap and / or insulating materials. Heat flow between the profile segments and the sidewall shells is reduced, and energy efficiency is improved. The gap is evacuated in an evacuated, enclosed area, so that a particularly low heat flow is generated.

[0021] A further preferred embodiment provides that the sidewall shells are thermally decoupled from the center mechanism, in particular by means of a gap and / or insulating materials. Thermally decoupling the profile segments from the sidewall shells reduces the heat flow between these components, thereby increasing energy efficiency and enabling more targeted heating of individual areas of vehicle tires.

[0022] A further preferred embodiment provides that the center mechanism supports a bellows, or the lower part of the heating press has a lower bead ring and the upper part of the heating press has an upper bead ring, wherein the bead rings have a geometry for forming a gas-tight seal with a bead of a vehicle tire. Supporting the vehicle tire by means of a bellows is particularly simple and has proven advantageous when using condensing vapors. The use of bead rings has proven particularly advantageous when using non-condensing heating media, since it eliminates the need to replace the bellows and eliminates damage to the vehicle tire caused by the bellows.

[0023] A further preferred embodiment provides for a first actuator and a second actuator to be arranged coaxially and driven hydraulically, with the pressure plate preferably being movable by a circular cylinder. This provides a simple coaxial arrangement of the actuators, so that the forces for pressing the pressure plate and the bead ring can be applied coaxially from one side of the tire.

[0024] Another preferred embodiment provides that the lower part of the curing press has a central mechanism that moves the lower bead ring. Moving the lower bead ring allows the tire to be separated from the lower sidewall shell after the vulcanization process, which allows for easier and faster removal of the tire from the curing press.

[0025] Another preferred embodiment provides for the heating medium to be a dry heating medium, in particular a gas. By using a dry heating medium, the removal of the condensate after vulcanization can be eliminated. The heating medium can largely be reused repeatedly, since it is not lost as condensate.

[0026] Another preferred embodiment provides for the heating medium in the green tire to be circulated or stagnated. Circulating the heating medium through the green tire allows for more uniform heat transfer into the green tire over time and across the surface of the green tire exposed to the heating medium. Stagnation of the heating medium, on the other hand, allows for the production of a particularly cost-effective heating press and the implementation of a particularly simple process.

[0027] According to the invention, a method for operating an electrically heated heating press, in particular a heating press according to the invention, is provided, wherein the following steps are carried out: a) loading the opened heating press by inserting the vehicle tire to be vulcanized, b) moving a container by a first stroke in the axial direction towards a heating press lower part, to create an area enclosed by a heating press upper part and the heating press lower part from the environment, c) generating a negative pressure in the enclosed area, d) cambering the vehicle tire with a heating medium, e) moving the container by a second stroke in the axial direction towards the heating press lower part, wherein profile segments of the vulcanizing mold are moved together in the radial direction, f) heating the green tire by means of an electrical heating element, g) opening the heating press and unloading the vulcanized vehicle tire.

[0028] By creating a vacuum in the enclosed area, valves in the profile segments can be eliminated, allowing the profile segments to be realized with a thinner material thickness. The electric heating elements can be positioned particularly close to the vehicle tire, thereby reducing the heated mass and the heating press releasing less energy into the environment. A further preferred embodiment provides that between step c) and step d), an upper bead ring is brought into contact with the bead of the vehicle tire. This allows the vehicle tire to be separated from the enclosed area, thus eliminating the need for a bellows.

[0029] 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.

[0030] Fig. 1 shows a partial area of ​​a heating press for vulcanizing a vehicle tire with electrically heated profile segments and sidewall shells;

[0031] Fig. 2 a heating press in the open state.

[0032] Figure 1 shows a heating press 1 for vulcanizing a vehicle tire, comprising an upper heating press part 2 and a lower heating press part 3. The upper heating press part 2 has profile segments 4 and an upper sidewall shell 5. The lower heating press part 3 has a lower sidewall shell 6. The inner surfaces of the sidewall shells 5, 6 and the profile segments 4 come into contact with the vehicle tire. The outer surfaces of the sidewall shells 5, 6 and the profile segments 4 are in surface contact with a thermal conductor 7 in the form of a silicone film. The silicone film serves to conduct a heat flow with a low thermal resistance from heating elements 8 into the sidewall shells 5, 6 and the profile segments 4. For this purpose, the heating element 8 is designed as a heating film that is in surface contact with the silicone film.The connection between the profile segments 4 and the side wall shells 5, 6 to the silicone film is force-locked and can be easily released by removing the profile segments 4 and the side wall shells 5, 6.

[0033] On the side facing away from the silicone foil, the heating foil is in surface contact with an insulating material 9. The insulating material 9, which is made of fiber-reinforced plastic with a material thickness of 40 mm, is designed to minimize heat flow into the segment ring 10 and the container 26. The electrical heating elements 8 are supplied with electrical energy via electrical lines 11.

[0034] In the illustrated retracted state of the heating press 1, the side wall shells 5, 6 are in contact with the profile segments 4 in the area of ​​their inner surfaces. In the cross-section, a recess 12 is formed in the course of the outer surface between the side wall shells 5, 6 and the profile segments 4 in order to thermally decouple the side wall shells 5, 6 from the profile segments 4.

[0035] The sidewall shells 5, 6 are thermally decoupled from the center mechanism 13 by means of a fiber-reinforced plastic to minimize heat flow from the center mechanism 13 into the sidewall shells 5, 6. Temperature sensors 14 arranged in the profile segments 4 determine the tread temperature of the vehicle tires.

[0036] Figure 2 shows a heating press 1 according to the invention for vulcanizing a vehicle tire with a vehicle tire 16 placed on the lower bead ring 15 in the open state.

[0037] The heating press 1 has a heating press lower section 3 with a lower plate 17. A lower sidewall shell 6 for forming a vehicle tire geometry is arranged on the lower plate 17. The center mechanism 13, which is sealingly connected to a sealing plate 18, projects through the lower plate 17 into the vehicle tire 16 coaxially with the lower bead ring 15. The center mechanism 13 has nozzles in its upper region for bringing the vehicle tire 16 into direct contact with a heating medium. The center mechanism 13 is connected to a heating medium source below the lower plate 17. The sealing plate 18 is sealingly connected circumferentially to the lower bead ring 15, so that after the vehicle tire 16 has been cambered, the vehicle tire 16, together with the lower bead ring 15, the sealing plate 18, and the center mechanism 13, tightly closes the opening arranged below the vehicle tire 16.The heating press 1 further comprises a heating press upper part 2 with an upper plate 19 and a locking ring 20 arranged below the upper plate 19. The locking ring 20 has a beveled inner surface on which the segment ring 10 is mounted for axial and radial movement.

[0038] Arranged coaxially with the segment ring 10 is an upper sidewall shell 5, which accommodates the upper bead ring 22. The inner circumference of the upper bead ring 22 is sealingly connected to a sealing plate 18. After the vehicle tire 16 has been cambered, the upper bead ring 22 seals the upper opening of the vehicle tire 16 with the sealing plate 18.

[0039] The heating press upper part 2 has a first actuator 23, which is designed as a cylinder, and a second actuator 24, which is designed as a circular ring cylinder, which are arranged coaxially to each other and to the bead rings 15, 22.

[0040] The circular cylinder is connected to a pressure plate 25 and moves it axially. The cylinder is connected to a sealing plate 18 and, via this, to the upper bead ring 22, which moves it axially. Both cylinders are in their upper position, so that the pressure plate 25 is located on the upper heating plate 19 and the upper bead ring 22 is located on the upper side wall shell 5. The heating press upper part 2 is mounted for movement (not shown).

[0041] If both cylinders are moved by a first stroke toward the heating press lower part 3, the segment ring 10, which is mounted in a container 26, moves downward in the axial direction 27 and outward in the radial direction. The profile segments 4 forming the segment ring 10 thereby move apart. The upper bead ring 22 remains in contact with the upper side wall shell 5. If the heating press upper part 2 is in a lower position, seals 28 seal the heating press upper part 2 and the heating press lower part 3 together from the environment. A vacuum in the enclosed area of ​​the heating press 1 can be generated by means of a vacuum pump.

[0042] Heating press Heating press upper part Heating press lower part Profile segment Upper sidewall shell Lower sidewall shell Thermal conductor Heating element Insulation material Segment ring Electrical line Recess Center mechanism Temperature sensor Lower bead ring Vehicle tire Lower plate Sealing plate Upper plate Locking ring Upper bead ring First actuator Second actuator Pressure plate Container Axial direction Seal

Claims

Patent claims 1. Heating press (1) for vulcanizing a vehicle tire (16), comprising a heating press upper part (2) and a heating press lower part (3), wherein a container (26) having a heated upper sidewall shell (5) and heated profile segments (4) is arranged on the heating press upper part (3), wherein the heating press lower part (3) has a heated lower sidewall shell (6), wherein the heating press upper part (2) is mounted so as to be movable relative to the heating press lower part (3), wherein the heating press upper part (2), the container (26), and the heating press lower part (3) are connected in such a way that the profile segments (4) come into contact with one another when the heating press upper part (2) approaches the heating press lower part (3), wherein the heating press (1) has a central mechanism (13) with gas outlet openings for filling a vehicle tire (16). with a heating medium, characterized inthat seals (28) are arranged on the heating press upper part (2) and / or on the heating press lower part (3) for sealing the area enclosed by the heating press upper part (2) and by the heating press lower part (3) from the environment, wherein the heating press upper part (2) and / or the heating press lower part (3) has an opening for applying a negative pressure in the enclosed area, wherein the profile segments (4) and / or the upper side wall shell (5) and / or the lower side wall shell (6) are heated electrically by means of at least one heating element (8), wherein the at least one heating element (8) is in contact with the profile segments (4) and / or the upper side wall shell (5) and / or the lower side wall shell (6) directly or by means of a thermal conductor (7).

2. Heating press (1) according to claim 1, characterized in that the heating element (8) is a heating cartridge, in particular a spiral tube heating cartridge, or a heating foil.

3. Heating press (1) according to claims 1 or 2, characterized in that the at least one heating element (8) is mounted separably from the profile segments (4) and / or at least one of the side wall shells (5, 6), wherein the Profile segments (4) and / or at least one of the side wall shells (5, 6) is preferably separable from the at least one heating element (8), wherein the at least one heating element (8) is mounted on the heating press upper part (2) or on the heating press lower part (3).

4. Heating press (1) according to claims 1 or 2, characterized in that a temperature sensor (14) is arranged on at least one heating element (8) and / or in at least one profile segment (4) and / or in at least one side shell (5, 6).

5. Heating press (1) according to one of the preceding claims, characterized in that the thermal conductor (7) is a conductive foil, in particular a compressible conductive foil, or a conductive paste.

6. Heating press (1) according to one of the preceding claims, characterized in that the heating elements (8) are thermally decoupled, in particular by means of a gap and / or insulation materials (9), preferably with fiber-reinforced materials, particularly preferably with glass-fiber-reinforced plastics, to at least one profile segment (4) and / or to at least one container (26).

7. Heating press (1) according to one of the preceding claims, characterized in that the profile segments (4) are thermally decoupled from the side wall shells (5, 6), in particular by means of a gap and / or insulation materials (8).

8. Heating press (1) according to one of the preceding claims, characterized in that the side wall shells (5, 6) are thermally decoupled from the central mechanism (13), in particular by means of a gap and / or insulation materials (8).

9. Heating press (1) according to one of the preceding claims, characterized in that the central mechanism (13) supports a bellows or the heating press lower part (3) has a lower bead ring (15) and the The heating press upper part (2) has an upper bead ring (22), wherein the bead rings (15, 22) have a geometry for forming a gas-tight seal with a bead of a vehicle tire (16).

10. Heating press (1) according to one of the preceding claims, characterized in that a first actuator (15) and a second actuator (16) are arranged coaxially and are hydraulically driven, wherein preferably the pressure plate (17) is movable by a circular ring cylinder.

11. Heating press (1) according to one of the preceding claims, characterized in that the heating press lower part (4) has a central mechanism (7) which moves the lower bead ring (2).

12. Heating press (1) according to one of the preceding claims, characterized in that the heating medium is a dry heating medium, in particular a gas.

13. Heating press (1) according to one of the preceding claims, characterized in that the heating medium in the green tire can be circulated or stagnated by a circuit.

14. A method for operating an electrically heated heating press (1), in particular according to one of the preceding claims, characterized in that the following steps are carried out: a) loading the opened heating press (1) by inserting the vehicle tire (16) to be vulcanized, b) moving a container (26) by a first stroke in the axial direction (27) towards a heating press lower part (3) to create an area enclosed by a heating press upper part (2) and the heating press lower part (3) to the environment, c) generating a negative pressure in the enclosed area, d) cambering the vehicle tire (16) with a heating medium, e) moving the container (26) by a second stroke in the axial direction (27) in the direction of the heating press lower part (3), wherein profile segments (4) of the vulcanizing mold are moved together in the radial direction, f) heating the green tire by means of an electrical heating element, g) opening the heating press (1) and unloading the vulcanized vehicle tire (16).

15. A method for operating an electrically heated heating press (1) according to claim 14, characterized in that between step c) and step d) an upper bead ring (22) is brought into contact with the bead of the vehicle tire (16).

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