JPS62211109A - Control method for feeding heat and pressure medium in type press - Google Patents

Abstract

PURPOSE:To contrive to improve control accuracy by achieving the feeding control for heated and pressure medium into a bladder by means of flow rate control values providing in a feeding flow path and an exhausting flow path, and the pressure and/or temperature detecting sensors for the feed back into said valves. CONSTITUTION:The feeding flow path 11a and the exhausting flow path 11b of steam are provided beside a movable top force 2 and a stationary bottom force 3 with the flow rate control valve 6 and the pressure sensor 9 for feed back at the side of the feeding flow path 11a. As steam feeding control, feeding flow paths 12a, 12a1, and 12a2 are constituted respectively with the flow rate control valve 6, pressure sensor for monitoring and the temperature sensor 10 for feed back, and further with the flow rate control valve 6 and the pressure sensor 9 for feed back, and they are connected to a feed pipe 13. Simultaneously, the control valve 15 for controlling the flow rate of exhausted steam is provided at the side of the exhausting flow path 12b connected to an exhausting pipe 14 with the pressure sensor 16 for feed back.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to controlling the heating of upper and lower molds in a tire press and the supply of a thermopressure medium to the bladder, particularly the supply of a thermopressure medium to the bladder. This invention relates to a system that enables the content of tire vulcanization to be enhanced with the aim of improving control accuracy.

(Prior Art) Tire presses that vulcanize and mold green tires using upper and lower molds that can be opened and closed and a bladder that can be expanded and contracted at the center of the lower mold are well known. That is, the lower mold is fixedly installed on the press frame, and the upper mold is provided so that it can be opened and closed toward the lower mold, and a central mechanism that can be raised and lowered is placed in the center of the lower mold. A green tire is set in the upper and lower molds that are closed using a bladder made of an elastic flexible material such as rubber that can be expanded and deformed, and the bladder is attached to the inner surface of the tire to tighten the upper and lower molds. The green tire is vulcanized and molded using pressure, heat, and internal pressure from a thermopressure medium supplied to the inside of the bladder in response to the external pressure on the mold side. What is important in the tire vulcanization molding process is to maintain the upper and lower molds in a constant temperature range, and to maintain the temperature and pressure inside the bladder in an appropriate temperature and pressure range depending on the vulcanization stage. This is to maintain a satisfactory vulcanization molding content.

Conventionally, when heating the upper and lower molds and supplying a thermopressure medium to the bladder, a heat medium such as steam (saturated steam) is used as is known, and the relationship between the pressure and temperature is kept constant. For the mold, a heating platen is built into the platen that supports the mold, and steam is supplied into the heating platen.
In addition, for the bladder, a supply/discharge hole is provided in the hub of the lower crumbling ring that grips the lower end of the bladder in the central mechanism.
By supplying steam into Prada from the supply and discharge pipes connected to the supply and discharge pipes, the required temperature and pressure field ranges were obtained, and the supply was controlled by pressure reducing valves, etc. It is something. Recently, with advances in sensor technology and automatic control technology, the temperature and pressure of the heating medium to be supplied is measured along the medium supply line, and this measurement value is fed back to the supply of the heating medium. Control systems that automatically adjust the valve opening to obtain the desired temperature and pressure are the mainstream, and one common example is shown in Figure 2. That is, the figure shows an example of controlling the supply of steam as a heating medium or thermopressure medium to the upper and lower molds and the bladder. The upper mold 2 is supported by a platen 3 and a platen L, respectively, and each of these platens 1.3 has a built-in heating platen (not shown), and a steam supply channel 11a and a steam supply passage 11a are connected to the heating platen. A flow rate control valve 6 is provided on the inlet side, that is, in the middle of the flow path 11a, and a pressure sensor 9 is provided upstream from this, and the sensor 9 controls the flow of the supplied steam. In addition to measuring the pressure value, this measured value is compared with the set value, and the opening degree of the control valve 6 is automatically adjusted so that the required set value is always maintained to ensure that the heating temperature (pressure) in the molds 2 and 3 is appropriate. This is to ensure proper retention. Steam supply control to bladder 5 is as follows:
As mentioned earlier, the bladder 5 is formed into a cylindrical shape of rubber or the like on the upper and lower clamp ring hubs of the central mechanism (not shown) installed in the central position of the lower mold 3 through the press frame. Both upper and lower ends of the bladder 5 are gripped, and through the vertical movement of the upper and lower clamp ring hubs, it can be expanded and contracted from a straight cylindrical shape to a curved shape along the inner surface of the green tire shown in the figure. A supply pipe 13 and a discharge pipe 14 are connected to the provided supply hole and discharge hole (both not shown), respectively.A steam supply channel 12a from the outside is connected to the supply pipe 13, and a steam supply passage 12a from the outside is connected to the supply pipe 13. The discharge flow path 12b to the outside is connected, and in the illustrated example, the supply flow path 12a
As shown in FIG. Although a flow path 12a2 for supplying lower pressure steam for the shaving operation and for the shaving process is shown, both flow paths 12a and 12a are shown.
A flow control valve 6.6 is disposed on the upstream side of each of the flow paths 12a! is merged into the flow path 12a+ side via the three-way piston valve 7 so that communication can be freely interrupted.
As shown in the figure, a pressure sensor 9, a temperature sensor 10, and a pressure sensor 9 are provided on the downstream side of the 2a and 12a2, respectively, and a three-way piston valve 7 and an on/off valve 8 are provided on the discharge flow path 12b side. During the shaving process and vulcanization molding process, the pressure measurement value from the pressure sensor 9 is fed back during the shaving process to automatically adjust the opening degree of the flow rate control valve 6, and the pressure sensor 9 and temperature sensor are used during the vulcanization molding process. Automatic control is performed by feeding back the pressure measurement value and temperature measurement value for monitoring by 10 and adjusting the opening degree of the flow control valve 6 to maintain the target temperature and pressure. Although there are some modifications, the supply control of the heating medium or thermopressure medium to the upper and lower molds 2.3 and the bladder 5 uses the method shown in FIG. 2.

(Problems to be Solved by the Invention) The conventional control system described above has the following problems. That is, on the upper and lower molds 2 and 3, the upper mold 2 side opens and closes by vertically raising and lowering or rotating up and down with respect to the fixed upper mold 3, and when it closes, it is pressurized and locked via a mold clamping cylinder, etc. And since the mold is exposed, it is extremely easy to detect the heating temperature.Heating does not necessarily have to be done with steam; it is also possible to use electrical heating means, as shown in the figure. Even when steam is used, it is relatively easy to control it if the steam supply pressure is accurately detected.

On the other hand, regarding the pressure and temperature inside the bladder 5,
Since the bladder 5 is a sealed bag cylinder and is completely hidden inside the green tire during vulcanization molding, it is difficult to directly measure its pressure and temperature. For this reason, the bladder 5
In order to control the thermopressure medium using a fluid such as steam inside the supply channel 1, as illustrated in Fig. 2,
It is uniquely determined only by the change in the opening degree of the flow rate control valve 6 by feeding back the respective measurement values from the sensors 9, 10 and 9 on the upstream side of the flow paths 2a to 12a+ and 12az. . Therefore, there is an error of +α between the actual pressure and temperature inside the bladder 5 and the values measured by the sensors 9 and 10 for control, and therefore control is performed using set values that take this into account in advance. There is a problem in that the control accuracy cannot be said to be sufficient, and in the vulcanization molding of such tires, the temperature and pressure of the thermopressure medium in the bladder 5 that is in close contact with the inner surface of the tire is This is an even more important point regarding the heating and pressurization of the upper and lower mold sides, and is also a point that cannot be left unresolved in determining the success or failure of vulcanization molding.

(Means for Solving the Problem) In order to solve the problem of the content of control in the bladder 5, the present invention controls the supply amount to the bladder 5 by using a temperature sensor 10 or a pressure sensor on the supply channel 12a side. 9, and not only open the valve 7.8 on the discharge channel 12b side to allow the flow to flow unilaterally, but also control the discharge channel 12b side in the same way as the supply channel 12a side. By doing this, it is possible to improve the control accuracy. Specifically, in a tire press that consists of upper and lower molds that can be opened and closed, and a bladder that can be expanded and contracted at the center of the lower mold. When heating the upper and lower molds and continuously supplying a thermopressure medium to the inside of the bladder during vulcanization molding, the supply of the thermopressure medium to the inside of the bladder is controlled by controlling the flow of the thermopressure medium to be supplied to the inside of the bladder. This is carried out via flow rate control valves provided separately in the flow path and the discharge flow path from the inside, and pressure and/or temperature detection sensors for feedback to the valves.

(Function) According to the present invention, as shown in FIG.
, on the fixed lower mold 3 side, a steam (thermopressure medium) supply channel 11a and a discharge channel 11b are connected together with a flow rate control valve 6 on the supply channel 11a side and a pressure sensor 9 for feedback to the valve 6. In order to control the supply of thermopressure medium (steam) to the bladder 5, the supply channels 12a to 12a to 12a2 are connected to a flow rate control valve 6, a pressure sensor for monitoring, a temperature sensor 10 for feedback, and Together with the flow rate control valve 6 and the feedback pressure sensor 9, the same flow path is configured as shown in the figure and connected to the supply pipe 1 on the central mechanism side.
A new control valve 15 for controlling the flow rate of steam discharge is installed on the exhaust flow path 12b side connected to the exhaust pipe 14 on the central mechanism side.
It is provided together with a pressure sensor 16 for feedback provided upstream of the valve 15 of b, and a three-way piston valve 7 and an on/off valve 8 similar to the conventional ones are provided downstream of the valve 15. By providing the flow rate control valve 15 in the discharge passage 14 on the bladder 5 side together with the pressure sensor 16 for feedback, the flow rate control valve 15 on the discharge side can be The bladder is kept fully closed until the pressure rises to the desired set pressure by measuring the pressure value using the pressure sensor 9, and then the opening of the valve 15 is automatically adjusted to keep the pressure inside the bladder constant to reduce the discharge amount. It can be controlled. In other words, the opening degree of the valve 15 can be precisely adjusted so that the pressure value measured by the pressure sensor 9 is set to a preset value. By controlling the internal pressure of the bladder to a constant value, the temperature inside the bladder can be indirectly controlled. Compared to the control only on the path 12a side, it is possible to perform control operations on both the supply side and the discharge side to apply more precise pressure and temperature ranges in the bladder that are appropriate for the vulcanization step. It can be done.

(Example) In FIG. 1 shown as an example of the present invention, the mold 2,
Although steam (saturated steam) is shown as the heating medium for the third side and the heating and pressurizing medium for the bladder 5 side, heating other than steam,
It is possible to use a pressurized medium, and it is also possible to use a heating medium other than fluid on the mold 2 and 3 sides, and it is necessary to use a fluid such as gas or liquid as the thermopressure medium on the bladder 5 side. However, it is also possible to use something other than steam.

However, using a common steam is easier in terms of operation and equipment. In the discharge channel 12b of the bladder 5, a flow rate control valve 15 and a pressure sensor 9 are newly installed as a sensor for feedback, but this is different from the pressure sensor 9 that was conventionally provided for monitoring on the supply channel 12a side. It is also possible to use a pressure sensor 9 as a feedback sensor for the flow rate control valve 15 in some cases.
In addition, a temperature sensor can also be used in combination, or even if only a temperature sensor is used instead of a pressure sensor, similar control effects can be obtained. The method of the present invention is applied to upper and lower molds 2.
As an application example, it is also possible to provide it on the supply flow path 11a and discharge flow path 11b sides in No. 3.

(Effects of the Invention) According to the present invention, during tire vulcanization molding, the supply of the thermopressure medium in the bladder 5, which is particularly important, is controlled, and the inner surface of the tire is vulcanized and the external force of pressure mold clamping is applied. It is superior in that it can form the optimal pressure and temperature field of the thermopressure medium, which acts as an internal pressure opposing the internal pressure, more accurately and with higher precision than conventional methods. In other words, the setting value is not only corrected by feedback based on the measured value of the thermo-pressure medium supplied into the bladder, but also the thermo-pressure medium discharged from the bladder is actually measured by a detection sensor, and based on this. By automatically controlling the opening of the flow rate control valve on the discharge side, it is possible to grasp the actual pressure and temperature inside the bladder in more detail and accurately, and to obtain feedback corrections that immediately respond to internal changes, improving control accuracy. Therefore, it is also possible to obtain satisfactory vulcanization molding contents.

[Brief explanation of drawings]

FIG. 1 is an overall view of an embodiment of the method of the present invention, and FIG. 2 is an overall view of an example of a conventional control method. 1.4--platen, 2--upper mold, 3--lower mold, 5-bladder, 6--flow control valve, 7°
°゛Three-way piston valve, 8...-on-off valve,
9.-Pressure sensor, 10.-Temperature sensor, lla, ll
b・-Mold side thermopressure medium supply passage, 12a, 12b-・
Bladder side thermopressure medium supply/discharge channel, 13-... supply pipe, 14-
Discharge pipe, 15-Flow rate control valve for bladder discharge flow path, 16----Pressure sensor.

Claims (1)

[Claims] (1) In a tire press consisting of upper and lower molds that can be opened and closed, and a telescopically deformable bladder placed in the center of the lower mold, the upper and lower molds are heated during vulcanization molding, and a thermopressure medium is continuously supplied to the inside of the bladder. In order to control the supply of the thermo-pressure medium to the inside of the bladder, flow control valves are provided separately in a flow path for supplying the thermo-pressure medium to the inside of the bladder and a flow path for discharging the thermo-pressure medium from the inside; A method for controlling the supply of a thermopressure medium in a tire press, characterized in that the method is carried out via a pressure and/or temperature detection sensor for feedback to the valve.