Method for vulcanising a vehicle tyre

Abstract

The invention relates to a method for vulcanising a vehicle tyre (2), comprising the steps of: - inserting a vehicle tyre (2) in a heating press (1), - generating a first process pressure in the vehicle tyre (2) or in a bellows (6), - closing the heating press (1) by moving the heating-press upper part (4) and the heating-press lower part (5) to one another, - generating a second process pressure in the vehicle tyre (2) or in the bellows (6), - vulcanising the vehicle tyre (2), - opening the heating press (1), - removing the vulcanised vehicle tyre (2) from the bellows (6) and / or the central mechanism (3).

Description

[0001] Description

[0002] Method for vulcanizing a vehicle tire

[0003] The invention relates to a method for vulcanising a vehicle tyre comprising the steps:

[0004] - Placing a vehicle tire in a heating press,

[0005] - Generating a first process pressure in the vehicle tire or in a bellows,

[0006] - Closing the heating press by moving the upper and lower parts of the heating press together,

[0007] - Generating a second process pressure in the vehicle tire or bellows, vulcanizing the vehicle tire,

[0008] - Opening the heating press,

[0009] - Removing the vulcanized vehicle tire from the bellows and / or center mechanism.

[0010] Furthermore, the invention relates to a heating press and a vehicle tire.

[0011] There are known curing presses that use steam to create overpressure in a bellows. The bellows presses the vehicle tire into the heating mold and heats it from the inside. Center-split curing presses have an upper and lower heating press sections, each with a sidewall area and a tread area. The upper and lower heating press sections are also heated with steam to vulcanize the vehicle tire. Once the vehicle tire is sufficiently vulcanized, the heating process is ended by reducing the process pressure in the bellows and removing the upper and lower heating press sections from the lower heating press sections. The heated vehicle tire is manually removed from the curing press and, in the process, removed from the lower heating press section.It has been shown that the longer contact time of the vehicle tire with the lower part of the heating press compared to the contact time of the vehicle tire with the upper part of the heating press causes some areas of the vehicle tire to be overheated, resulting in damage to the rubber network or reversion. This leads to increased rolling resistance and accelerated aging. Furthermore, more complex heating presses are known that feature a container with molded parts or segments that have an automated removal device to ensure that the vehicle tire is removed from the lower parts of the heating press immediately at the end of the heating process. Known removal devices are cost-intensive and require additional installation space.Furthermore, it has been shown that immediately removing the vehicle tire from the bellows at the end of the heating process is disadvantageous, since vehicle tires in this state tend to undergo plastic deformation and, for example, concentricity errors can occur.

[0012] Against this background, the invention is based on the object of designing a method and a curing press such that no areas of the vehicle tire are overheated during vulcanization, while keeping the design of the curing press as simple as possible and preferably easily retrofittable to existing curing presses. Furthermore, with a short process time, plastic deformation of the vehicle tires upon removal from the curing press should be avoided.

[0013] This object is achieved by a method according to the features of patent claim 1, as well as a heating press and a vehicle tire according to the independent claims. The subclaims relate to particularly useful developments of the invention.

[0014] According to the invention, a method for vulcanizing a vehicle tire is provided, comprising the steps of: a) placing a vehicle tire in a heating press, b) generating a first process pressure in the vehicle tire or in a bellows, c) closing the heating press by moving the heating press upper part and the heating press lower part towards each other, d) generating a second process pressure in the vehicle tire or in the bellows, e) vulcanizing the vehicle tire, f) reducing and adjusting the process pressure to an overpressure of at least 0.2 bar in the vehicle tire or in the bellows, g) opening the heating press, h) removing the vulcanized vehicle tire from the bellows and / or the center mechanism.

[0015] Reducing and adjusting the process pressure to an overpressure of at least 0.2 bar in the tire or bellows allows for reliable and reproducible completion of the vulcanization process on all outer surfaces of the tire at the end of the heating process, while ensuring particularly gentle storage of the tire. Removal from the lower part of the heating press is achieved because the tire moves upwards when the heating press is opened due to the overpressure within it.

[0016] A particularly uniform vulcanization of the vehicle tire is achieved. Supporting the vehicle tire through the center mechanism enables particularly easy removal of the vehicle tire from the curing press, thus reducing process times. Furthermore, at the end of the heating process, the center mechanism can be fed with a cold gas at a constant process pressure, which leads to accelerated cooling of the vehicle tire and, in particular, counteracts plastic deformation of the vehicle tire during removal from the center mechanism.

[0017] A preferred embodiment provides that after step g) and before step h), the overpressure in the vehicle tire or bellows is reduced. Reducing the overpressure in the vehicle tire or bellows ensures, on the one hand, particularly gentle storage of the vehicle tire during its movement relative to the upper part of the heating press and relative to the lower part of the heating press, and, on the other hand, enables particularly easy removal of the vehicle tire from the bellows or the center mechanism.

[0018] Another preferred embodiment provides that after step g) and before step h), the vehicle tire is cooled on its inside with a cold gas. This enables particularly rapid cooling of the vehicle tire from the inside, thereby expanding the possibilities for temperature control of the vehicle tire during vulcanization. Rapid cooling also enables a short process time, while avoiding plastic deformation of the still-heated vehicle tire.

[0019] A further preferred embodiment provides that in step f) the process pressure is set to an overpressure of at least 0.3 bar, preferably of at least 0.4 bar, more preferably of at least 0.6 bar, and preferably to a maximum of 2 bar, more preferably to a maximum of 1.5 bar, more preferably to a maximum of 1.2 bar and more preferably to a maximum of 1 bar in the vehicle tire or in the bellows. It has been shown that at a process pressure of at least 0.3 bar, particularly secure storage of the vehicle tire is achieved. Furthermore, it has been shown that at process pressures greater than 2 bar, the vehicle tire suffers quality losses due to the pressure and removal of the vehicle tire from the heating press is made more difficult.

[0020] A further preferred embodiment provides that, in step f), water vapor is removed from the bellows or the vehicle tire, generating a pressure of less than 0.2 bar, and subsequently, a dry gas is used to adjust the process pressure. This effectively reduces the temperature inside the vehicle tire. Furthermore, using a dry gas allows the process pressure to be adjusted simply, with high accuracy and reliability.

[0021] According to the invention, a heating press is provided for vulcanizing a vehicle tire, preferably a two-wheeler tire, in particular a bicycle tire, preferably for carrying out a method according to the invention, wherein the heating press has a heating press upper part and a heating press lower part, wherein the heating press upper part and the heating press lower part each have a sidewall region and a tread region, wherein the heating press has a center mechanism for supporting the vehicle tire, wherein the heating press has an automatic dry gas valve.

[0022] The automatic dry gas valve enables the process pressure to be reduced and adjusted to an overpressure of at least 0.2 bar in the vehicle tire or bellows with process reliability and good reproducibility at the end of the heating process.

[0023] According to the invention, a vehicle tire is produced using a method according to the invention and preferably using a heating press according to the invention. Vehicle tires produced in this way can be manufactured with particularly reliable and efficient processes and reliably exhibit, for example, particularly low rolling resistance.

[0024] According to the invention, a curing press is provided for vulcanizing a vehicle tire, preferably a two-wheeler tire, in particular a bicycle tire. A curing press upper part and a curing press lower part each have a sidewall region and a tread region. The curing press has a center mechanism for supporting the vehicle tire, wherein the center mechanism is configured to automatically move the vehicle tire in a stored state to the curing press upper part and the curing press lower part.

[0025] The automated movement of the center mechanism to the upper and lower sections of the curing press, i.e., to all curing press components that shape the vehicle tire, enables the vulcanization process to be completed reliably and with good reproducibility at the end of the curing process on all outer surfaces of the vehicle tire, while the tire is stored in a particularly gentle manner. This ensures particularly uniform vulcanization of the vehicle tire. Supporting the vehicle tire with the center mechanism enables particularly easy removal of the vehicle tire from the curing press, thus reducing process times.Furthermore, at the end of the heating process, the center mechanism can be fed with a cold gas at a constant process pressure, which leads to accelerated cooling of the vehicle tire and, in particular, counteracts plastic deformation of the vehicle tire when it is removed from the center mechanism.

[0026] A preferred embodiment provides that the center mechanism has a

[0027] Bellows for supporting the vehicle tire. The use of a bellows for supporting the vehicle tire enables a particularly simple design of the center mechanism. Furthermore, a bellows prevents storage marks of the center mechanism on the vehicle tire.

[0028] A further preferred embodiment provides that the bellows can be pressurized using steam and / or a gas. The use of steam has proven to be particularly cost-effective, especially when steam is already available for external heating of the heating press. Gases, i.e., dry gases, also make it easy to generate a process pressure, with gases also enabling a temperature-independent process pressure. The use of steam, particularly at the beginning of the heating process, and gas, particularly during the further course of the heating process, in combination has also proven advantageous with regard to the energy input into the vehicle tire.

[0029] A further preferred embodiment provides that the center mechanism can be moved by an electric motor or by means of a hydraulic cylinder.

[0030] Electric motors and hydraulic cylinders have proven to be cost-effective and particularly reliable for moving the center mechanism.

[0031] A further preferred embodiment provides for the centering mechanism to be adjustable to different tire widths. The adjustability of the centering mechanism to different tire widths allows for easy conversion of the heating press to different vehicle tires.

[0032] A further preferred embodiment provides that the center mechanism has bellows clamping rings, wherein the center mechanism is movable with a constant distance between the bellows clamping rings to the upper part of the heating press and the lower part of the heating press. A constant distance between the bellows clamping rings during the movement to the upper part of the heating press and the lower part of the heating press enables particularly gentle storage of the vehicle tire at the end of the vulcanization process. For example, particularly good concentricity of the vehicle tire is ensured. A further preferred embodiment provides that the center mechanism is configured to clamp the vehicle tire in a sealing manner in its bead areas for storage of the vehicle tire. Clamping the vehicle tire in its bead areas enables the vehicle tire to be clamped directly and sealingly to the center mechanism.This eliminates the need for a bellows, eliminating the cost of purchasing and replacing them. Furthermore, rejects due to defective bellows are avoided.

[0033] According to the invention, a method for vulcanizing a vehicle tire is provided, in particular with a heating press according to the invention according to one of the preceding claims, comprising the following steps: a) inserting a vehicle tire into a heating press, b) generating a first process pressure in the vehicle tire or in a bladder, c) closing the heating press by moving the heating press upper part and the heating press lower part towards each other, d) generating a second process pressure in the vehicle tire or in the bladder, e) vulcanizing the vehicle tire, f) reducing the process pressure to a lower overpressure in the vehicle tire or in the bladder, g) opening the heating press, h) moving a center mechanism relative to the heating press upper part and to the heating press lower part, i) removing the vulcanized vehicle tire from the bladder and / or the center mechanism.

[0034] The automated movement of the center mechanism to the upper part of the heating press and the lower part of the heating press enables the vulcanization process to be completed reliably and with good reproducibility at the end of the heating process on all outer surfaces of the vehicle tire. This results in particularly uniform vulcanization of the vehicle tire. Supporting the vehicle tire by the center mechanism enables particularly easy removal of the vehicle tire from the heating press, thereby reducing process times. Furthermore, the center mechanism can be fed with a cold gas at a constant process pressure at the end of the heating process. This leads to accelerated cooling of the vehicle tire, which in particular counteracts plastic deformation of the vehicle tire upon removal from the center mechanism.

[0035] A preferred embodiment provides that after step h) and before step i) the excess pressure in the vehicle tire or in the bellows is reduced.

[0036] A further preferred embodiment provides that after step h) and before step i) the vehicle tire is cooled on its inside with a cold gas.

[0037] According to the invention, a vehicle tire is provided, which is preferably produced using a method according to the invention. A vehicle tire produced using a heating press according to the invention, and in particular a method according to the invention, can be produced cost-effectively and reliably with particularly high quality in terms of the vulcanization produced and the geometry produced.

[0038] The invention is susceptible of numerous embodiments. To further clarify its basic principle, a possible embodiment is illustrated in the drawings and described below.

[0039] Fig. 1 a heating press for vulcanizing a vehicle tire with a center mechanism.

[0040] Figure 1 shows four views of a heating press 1 for vulcanizing a vehicle tire 2, with the heating press 1 being in a different state in each view a) to d). The heating press 1 has a center mechanism 3, a heating press upper part 4, and a heating press lower part 5. The heating press upper part 4 and a heating press lower part 5 each have a sidewall area and a tread area. The heating press 1 is a center-split press; it has no mold segments. The center mechanism 3 is movably mounted on the heating press lower part 5, as can be seen in view c). The center mechanism 3 has a bellows 6, which is provided for supporting and pressurizing the vehicle tire 2. In order to vulcanize the vehicle tire 2, the vehicle tire 2 is mounted on the bellows 6 in the heating press 1, and the heating press 1 is closed. The process pressure in bellows 6 is increased. The vulcanization process is carried out.To complete the vulcanization process, the process pressure in the bellows 6 is reduced, and, as shown in view b), the upper part 4 of the heating press is moved upwards. At the same time, or immediately thereafter, the center mechanism 3 is moved upwards so that the vehicle tire 2 is spaced apart from both the upper part 4 of the heating press and the lower part 5 of the heating press. The vehicle tire 2 is supported on the bellows 6, which is filled with a low pressure. To accelerate the cooling of the vehicle tire 2, a gas exchange takes place in the bellows 6, with cold gas flowing into the bellows 6 and gas heated by the bellows 6 flowing out.

[0041] After the vehicle tire 2 has sufficiently cooled, it is gripped by a gripping device 7. The pressure in the bellows 6 is further reduced, and the bellows 6 is moved downwards out of the vehicle tire 2. The vehicle tire 2 is positioned solely by the gripping device 7. The gripping device 7 removes the vehicle tire 2 from the hot-press area and transports it to further processing steps.

[0042] Reference symbols Heating press Vehicle tire Center mechanism Heating press upper part Heating press lower part Bellows Gripping device

Claims

Patent claims 1. Method for vulcanizing a vehicle tire (2) with the steps: a) inserting a vehicle tire (2) into a heating press (1), b) generating a first process pressure in the vehicle tire (2) or in a bellows (6), c) closing the heating press (1) by moving the heating press upper part (4) and the heating press lower part (5) towards each other, d) generating a second process pressure in the vehicle tire (2) or in the bellows (6), e) vulcanizing the vehicle tire (2), f) reducing and adjusting the process pressure to an overpressure of at least 0.2 bar in the vehicle tire (2) or in the bellows (6), g) opening the heating press (1), h) removing the vulcanized vehicle tire (2) from the bellows (6) and / or the center mechanism (3).

2. Method according to claim 1, characterized in that after step g) and before step h) the excess pressure in the vehicle tire (2) or in the bellows (6) is reduced.

3. Method according to claims 1 or 2, characterized in that after step g) and before step h) the vehicle tire (2) is cooled on its inside with a cold gas.

4. Method according to one of the preceding claims, characterized in that in step f) the process pressure is set to an overpressure of at least 0.3 bar, preferably of at least 0.4 bar, more preferably of at least 0.6 bar, and preferably to a maximum of 2 bar, more preferably to a maximum of 1.5 bar, more preferably to a maximum of 1.2 bar and more preferably to a maximum of 1 bar in the vehicle tire (2) or in the bellows (6).

5. Method according to one of the preceding claims, characterized in that in step f) water vapor is removed from the bellows (6), wherein a pressure of less than 0.2 bar is generated and a dry gas is subsequently used to adjust the process pressure.

6. Heating press (1) for vulcanizing a vehicle tire (2), preferably a two-wheeler tire, in particular a bicycle tire, preferably for carrying out a method according to one of the preceding claims, wherein the heating press (1) has a heating press upper part (4) and a heating press lower part (5), wherein the heating press upper part (4) and the heating press lower part (5) each have a sidewall region and a tread region, wherein the heating press (1) has a center mechanism (3) for supporting the vehicle tire (2), characterized in that the heating press has an automatic dry gas valve.

7. Vehicle tire (2) produced by a method according to one of claims 1 to 5 and preferably with a heating press (1) according to claim 6.

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