Tire heating press

Abstract

The invention relates to a device for the vulcanization of tire blanks and comprises at least one heatable mold for receiving the tire blank. The device further comprises at least one controllable supply device for a heating medium, which is provided with at least one valve (239). The valve comprises a positioning device that is actuated by a liquid fluid (25).

Description

[0001] The invention relates to a device for vulcanizing tire blanks, which has at least one heated mold for receiving the tire blank and which has at least one controllable supply device for the heating medium, which is equipped with at least one valve.

[0002] A number of manufacturing steps are carried out in the production of tires. In the first manufacturing step, extruded strips of elastomeric material are usually assembled on a building drum into a tire blank. This is often done using steel wire reinforcement inserts to produce so-called steel belt tires.

[0003] The tire blank is then transferred to a heating press and placed in a mold and typically subjected to internal pressure. Typically, the mold holding the tire blank may be heatable, and a heating medium may be introduced into the tire blank to apply internal pressure to it during vulcanization, which helps stabilize the predetermined tire contour.

[0004] Various substances can be used as heating medium. Steam, hot water or hot nitrogen are commonly used. Typically, the heating medium is fed into the vulcanization process via pneumatically operated valves. As a rule, so-called monostable valves are used. In particular, valves are used which are normally closed or normally open. In the heating medium supply area, valves are often used which are normally closed. The control medium forces the valves to open against the force of a spring. In the event of an emergency shutdown and / or loss of control pressure, the valves are brought into the closed state by the force of a spring. In the outlet area, valves are usually used which are normally open. Here, the springs push the valves into the open position in the event of a pressure drop. This ensures that the pressurized space is vented to the environment and is therefore pressure-free and therefore safe.

[0005] The use of electrically controlled valves is also known. However, these valves are often slow in terms of the switching times that can be achieved. Furthermore, these valves often cannot achieve a predetermined basic state in the open or closed position.

[0006] Another disadvantage is that with a larger nominal width of the valves there is a risk of a reduction in the pressure of the heating medium. Finally, relatively large actuating forces are often required.

[0007] In a typical tire manufacturing process, a large number of tire heating presses are often operated in the production halls. Pneumatically controlled valves require very complex pipelines for the supply of compressed gases. Leaks and other leaks in such pneumatic devices often lead to a loss of up to 80 percent of the compressed air used. Therefore, significantly more compressed air must be available than is required for the actual control processes. This means that larger and therefore more expensive compressors are required, or the number of compressors must be increased with corresponding costs. The costs do not only relate to the cost of the device itself, but also to the operating costs.

[0008] A press for vulcanizing semi-finished tires is already known from EP 2 308 662 A1, in which a heatable mold for receiving the semi-finished tires is equipped with a controllable supply device for the heating medium. The supply device is equipped with a valve.

[0009] A similar device for vulcanizing semi-finished tire products is also described in EP 2 567 808 A1.

[0010] EP 0 143 089 A2 describes pneumatic and hydraulic control devices in general. In particular, it is also explained that hydraulic devices allow high control speeds to be achieved and therefore have short switching times.

[0011] US 7156629 B2 already describes a device for vulcanizing tire blanks. The corresponding device is equipped with a heatable mold for receiving the tire blank. A heating medium is used to regulate the temperature of the mold, for which a controllable supply device is equipped with a valve. The valve is connected to a control valve.

[0012] The aim of the present invention is to make the regulation of the heating medium supply more efficient while maintaining technical quality.

[0013] This object is achieved by the features of independent claim 1.

[0014] Liquid fluid supply systems can be sealed much more effectively from the environment than gaseous fluid supply and distribution systems. In corresponding liquid fluid piping systems, leakage losses are therefore generally considerably lower than in corresponding gaseous fluid supply systems.

[0015] According to the invention, the positioning of the valve is precisely specified by the positioning device having a piston-cylinder arrangement.

[0016] In order to ensure the desired volume flows and the desired pressures, a pump is used according to the invention to transport the liquid fluid and to create pressure.

[0017] According to the invention, a sufficient supply of liquid fluid is ensured by the pump being connected to the tank.

[0018] Simple and at the same time extremely reliable control can be achieved by connecting at least one of the valves to a control valve.

[0019] To increase the safety of the system, it is proposed that at least one of the valves be designed as monostable.

[0020] The basic state of the valve may be given such that at least one of the valves has a spring to define a basic position.

[0021] According to one embodiment, it is assumed that the inlet valve is closed in the basic state.

[0022] It is also possible for the outlet valve to be open in the basic state.

[0023] According to another embodiment, the heating press 1 has at least one pressure control valve controlled by a liquid fluid.

[0024] Examples of embodiments of the invention are schematically illustrated in the drawings, which show: Fig. 1 a simplified representation of a heating press using the example of a column heating press and Fig. 2 a circuit diagram illustrating valve control when using a liquid fluid.

[0025] Figure 1 shows the design of a heating press (1). The heating press (1) is used for vulcanizing the material of a tire blank, which is not shown. To receive the tire blank, the heating press (1) has a mold (2), which consists of an upper mold half (3) and a lower mold half (4). In the illustrated embodiment, the lower mold half (4) is arranged immovably. The upper mold half (3) is positionable in the vertical direction. By positioning the upper mold half (3) accordingly, the mold (2) can be opened and closed.

[0026] The heating press (1) according to Figure 1 is designed as a column heating press and has columns (5, 6). Pistons (7, 8) are used to position the upper mold half (3), which are positionable relative to the cylinders (9, 10).

[0027] According to a further embodiment, the heating press (1) can also be implemented as a frame heating press.

[0028] Figure 2 shows a block diagram illustrating the supply of a heating medium to the mold region (2) to carry out the vulcanization of the tire blank there.

[0029] An inlet region (21) and an outlet region (22) are used to carry out the schematically illustrated vulcanization process (20). The necessary heating medium is supplied and discharged in these regions.

[0030] The inlet region (21) is provided with an inlet valve (23) and the outlet region (22) is provided with an outlet valve (24). Typically, the valves (23, 24) are designed as monostable valves.

[0031] The inlet valve (23) is closed in the basic state without the influence of the control medium. The outlet valve (23) is open without the influence of the control pressure. The corresponding basic positioning of the valves (23, 24) is typically achieved by using a spring, against which the force of the acting control pressure acts. Typically, such springs are implemented as compression springs.

[0032] The inlet valve (23) has a control line (25) and the outlet valve (24) is equipped with a control line (26).

[0033] A control valve (27) is connected to the control line (25). The control line (26) is equipped with a control valve (28).

[0034] According to a typical embodiment, the control valves (27, 28) are designed as 3- / 2-way valves. It is also particularly important to design the control valves (27, 28) to be electrically controlled.

[0035] The control valves (27, 28) are connected to the tank (31) via supply lines (29, 39). Typically, the liquid fluid stored in the tank (31) is conveyed to the supply lines (29, 39) by a pump (32).

[0036] The return of the liquid fluid to the tank (31) is carried out via the return line (33, 34).

Claims

1. A device for vulcanizing tire blanks, which has at least one heatable mold (2) for receiving a tire blank and which has at least one controllable supply device for a heating medium, which is equipped with at least one valve (23, 24), characterized in that the valve (23, 24) has a positioning device controlled by a liquid fluid, that the positioning device has a piston-cylinder arrangement, that a pump (32) is provided for conveying the liquid fluid and for generating pressure, that the pump (32) is connected to a tank (31) and that at least one valve (23, 24) is connected to a control valve (27, 28) which is designed as a 3- / 2-way valve.

2. Device according to claim 1, characterized in that at least one of the valves (23, 24) is designed as monostable.

3. Device according to any one of claims 1 or 2, characterized in that at least one of the valves (23, 24) has a spring for defining a basic positioning.

4. Device according to any one of claims 1 to 3, characterized in that the valve (23) is an inlet valve and is closed in the basic state.

5. Device according to any one of claims 1 to 4, characterized in that the valve (24) is an outlet valve and is open in the basic state.

6. Device according to any one of claims 1 to 5, characterized in that the heating press (1) has at least one pressure control valve controlled by a liquid fluid.