JP2003266523A - Control system of rubber continuous molding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control system of a rubber continuously molding apparatus capable of obtaining a stable discharge amount of a strip rubber even if the apparatus is miniaturized by reducing the length of a screw. <P>SOLUTION: The control system controls the rubber continuously molding apparatus equipped with a supply port 20c for supplying a rubber material which is treated for removing foreign matters in a front process, an extruder 20 for kneading the supplied rubber material to send out the same and a gear pump 21 for sending out the rubber material supplied from the extruder 20 to a molding cap 22 and constituted so as to mold the strip rubber used for molding a tire continuously extruded from the molding cap 2. This control system is equipped with a pressure sensor 30 for detecting the pressure in the gear pump 21, a pressure comparing means 13 for comparing the detected pressure with a set value 14 and a motor control means 15 for controlling the number of rotations of a motor 16 for driving the screw 20 of the extruder 20 on the basis of the comparison result of the pressure comparing means 13. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feeding section for feeding a rubber material which has been previously treated to remove foreign matter in a previous step, an extruder for kneading and feeding the fed rubber material, and this extruder. TECHNICAL FIELD The present invention relates to a control system for controlling a continuous rubber molding device including a gear pump that feeds a rubber material supplied from a mold to a molding die.

[0002]

2. Description of the Related Art A rubber molding process in a rubber continuous molding device is generally as follows. That is, the rubber material is supplied from the supply port, the supplied rubber material is kneaded and extruded by the screw of the extruder, and the extruded rubber material passes through the strainer to remove foreign matters, and the rubber from which the foreign matters are removed A gear pump pumps a fixed amount of it into the molding die, and a strip-shaped strip rubber having a predetermined cross-sectional shape is continuously extruded from the molding die for molding. This strip rubber is wrapped around the outer periphery of the molding drum,
The rubber layer of the tire is formed. Such a rubber continuous molding device is known, and is disclosed, for example, in Japanese Patent Laid-Open No. 2001-30338.

Here, in order to reduce the size of the continuous rubber molding device, it is conceivable to shorten the length of the screw of the extruder. An advantage of downsizing the continuous rubber molding device is that strip rubber extruded from the continuous rubber molding device can be directly supplied to the molding drum. In order to wind the strip rubber around the forming drum, the strip rubber must be moved in the direction along the drum axial direction of the forming drum. In this case, if the continuous rubber molding device can be miniaturized, the strip rubber can be wound around the outer periphery of the molding drum by moving the continuous rubber molding device itself. Therefore, in order to downsize the continuous rubber molding device, the length of the screw is shortened as described above, so that the continuous rubber molding device can be downsized.

[0004]

However, when the screw is shortened, there is a problem that the discharge amount of the strip rubber extruded from the molding die varies, and a strip rubber having a desired shape cannot be obtained. this is,
This is because the viscosity of the kneaded rubber material varies and the pressure inside the gear pump varies.

The present invention has been made in view of the above circumstances, and a problem thereof is that a stable discharge amount of strip rubber can be obtained even when the length of the screw is shortened to downsize the apparatus. It is to provide a control system for such a continuous rubber molding device.

In order to solve the above problems, a control system for a continuous rubber molding apparatus according to the present invention comprises a supply section for supplying a rubber material which has been subjected to a foreign matter removal treatment in a previous step. An extruder for kneading and feeding the supplied rubber material, and a gear pump for feeding the rubber material supplied from this extruder to a molding die, and strip rubber used for tire molding is continuously extruded from the molding die. A control system for controlling a continuous rubber molding device, which is a pressure sensor for detecting a pressure in a gear pump, a pressure comparing means for comparing the detected pressure with a set value, and a comparison result of the pressure comparing means. And a motor control means for controlling the number of rotations of a motor for driving the screw of the extruder based on the above.

According to this structure, first, the rubber material from which foreign substances have been removed in the previous step is supplied to the supply section of the continuous rubber molding device. Therefore, it is not necessary to provide the continuous rubber molding device with a strainer for removing foreign matters. The rubber continuous molding device can be downsized by that amount.

Further, a pressure sensor is provided to detect the pressure inside the gear pump. Then, the detected pressure is compared with a set value, and the rotation speed of the screw of the extruder is controlled so that the pressure value becomes a preset pressure value. Thereby, the pressure fluctuation in the gear pump can be suppressed. Therefore, the discharge amount of the strip rubber extruded from the molding die can be stabilized. as a result,
It is possible to provide a control system for a continuous rubber molding device that can obtain a stable strip rubber discharge amount even when the device is downsized by shortening the screw length.

As a preferred embodiment of the present invention, a temperature sensor for detecting the temperature in the gear pump, a temperature comparison means for comparing the detected temperature with a set value, and the above-mentioned result based on the comparison result of the temperature comparison means are used. An example of the gear pump includes a temperature control means for adjusting the temperature inside the gear pump.

If the temperature inside the gear pump of the continuous rubber molding device is not stable, the physical properties of the strip rubber extruded from the molding die become unstable. Further, when the gear pump is repeatedly operated and stopped, the temperature inside the gear pump fluctuates. Further, such a temperature variation also causes a variation in the amount of rubber discharged from the molding die.

Therefore, a temperature sensor for detecting the temperature inside the gear pump is provided as described above, and the temperature is controlled so as to reach a preset value. This stabilizes the temperature inside the gear pump. As a result, the physical properties of the molded strip rubber are stable and the discharge amount is also stable.

As another preferred embodiment of the present invention, the ratio (L / D) of the screw length L and the outer diameter D of the extruder.
However, it is 1 or more and 8 or less.

By performing the pressure control and the temperature control according to the present invention, the strip rubber can be stably discharged even when the L / D of the screw is set in such a numerical range. When (L / D) is less than 1, the rubber material is not sufficiently plasticized. Further, if (L / D) exceeds 8, the mechanism for moving the continuous rubber molding device becomes large and uneconomical.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a control system for a continuous rubber molding device according to the present invention will be described with reference to the drawings.

<Structure of Continuous Rubber Molding Device> This system includes a first continuous rubber extruder 1 (hereinafter referred to as “first extruder”).
And a second rubber continuous extrusion device 2 (hereinafter referred to as “second extrusion device”). The first extrusion device 1 includes a first extruder 10, a strainer 11, and a first molding die 12 as schematically shown in FIG. The first extruder 10 is a barrel 1 having a cylindrical cross section.
0a, a screw 10b, and a supply port 10c into which a rubber material is input are provided. From the supply port 10c,
The sheet-shaped rubber material manufactured in the mixing step which is the previous step is supplied. By rotating the screw 10b,
The rubber material is kneaded and fed forward.

The strainer 11 is shown in FIG. Figure 3
(A) is a side sectional view and (b) is a front view. In the strainer 11, a metal mesh 11b is fitted in a support 11a, and a large number of minute holes 11c are formed in the metal mesh 11b. A large number of ribs 11d are formed on the support 11a. The rubber material passes from the right side to the left side in FIG. The foreign material can be removed by passing the rubber material through the strainer 11.

The cross-sectional shape of the pre-process strip rubber (first strip rubber) discharged from the first molding die 12 is circular, square or rectangular, but is not limited to a particular shape. . Since the strip rubber in the previous step is supplied to the second extrusion device 2 described below, it may have a shape suitable for the purpose.

The second extruder 2 includes a small second extruder 20 and a gear pump 2 as schematically shown in FIG. 1 (b).
1 and a second molding die 22. The second extruder 20 includes a barrel 20a having a cylindrical cross section and a screw 20.
b and the supply port 20c are provided. Supply port 20c
From, the strip rubber extruded and molded by the first extrusion device 1 in the previous step is supplied. Screw 20b
Rotates to knead the rubber material and supply it toward the front.

The rubber material supplied by the screw 20b is supplied to the gear pump 21. It is not necessary to provide a strainer. This is because the foreign matter has already been removed in the previous process. Gear pump 21
Is equipped with a pair of gears 21a that are driven to rotate,
The rubber material is quantitatively supplied to the second molding die 22. Second
A strip rubber (second strip rubber) having a predetermined cross-sectional shape is discharged from the molding die 22. The cross section of the strip rubber has a triangular shape, a crescent shape, or the like.

The strip rubber extruded from the second molding die 22 is directly supplied to the molding drum 3 via the pressure roller 4. In order to wind the strip rubber around the forming drum 3, the second extruding device 2 may be moved along the drum axial direction while rotating the forming drum 3.

A pressure sensor 30 and a temperature sensor 31 are provided inside the gear pump 21. The pressure sensor 30 is provided on the tip side of the screw 20b on the gear 2 side.
It is provided near the entrance to 1a. Pressure sensor 30
Is installed in the wall surface of the casing and detects the pressure in the gear pump. In addition, the temperature sensor 31
Is in the same gear pump 21, but is provided immediately in front of the second molding die 22. Temperature sensor 31
Detects the temperature inside the gear pump 21.

<Characteristics of System Configuration> In the system according to the present embodiment, two types of extrusion devices, a first extrusion device 1 and a second extrusion device 2, are used for extrusion molding strip rubber. This will be described.
The first extrusion device 1 is configured as a large-sized device, kneads a rubber material, and removes foreign substances with a strainer 11.
The second extrusion device 2 is configured as a small device and directly supplies the strip rubber to the molding drum 3. In order to wind the strip rubber around the forming drum 3, it is necessary to move the strip rubber along the drum axial direction of the forming drum 3 (direction perpendicular to the paper surface of FIG. 1B). By reducing the size of the second extruding device 2 and moving the second extruding device 2 itself relative to the molding drum 3, it is possible to wind the strip rubber so that a desired rubber layer is formed. it can.

As described above, in the previous step, the rubber material is kneaded by the first extruder 1 and foreign matters are removed, so that the second extruder 2 can be downsized.
That is, the size can be reduced by shortening the length of the screw 20b of the second extrusion device 2. Further, since it is not necessary to provide the strainer 11, the size can be reduced accordingly. With respect to the length of the screw 20b, when the length is L and the outer diameter is D, as shown in FIG. 1B, 1 ≦ L / D ≦ 8 can be satisfied. Further, preferably, 3.5 ≦ L / D ≦ 5.5 can be satisfied. In a general extrusion apparatus, 12 ≦ L / D ≦ 16, so that the system of the present invention can be considerably downsized.

However, if the second extrusion device 2 is downsized,
Another problem arises. That is, when the screw 20b is shortened, the pressure and temperature inside the gear pump 21 are easily changed. Such fluctuations in pressure and temperature cause fluctuations in the discharge amount of the strip rubber discharged from the second molding die 22. If the discharge amount fluctuates, the shape of the molded strip rubber will also become unstable, and eventually it will not be possible to obtain a tire of desired quality. Therefore, in the present invention, a system for controlling pressure and temperature is constructed.

<Structure of Control System> Next, a system for controlling the pressure and temperature in the gear pump will be described with reference to the schematic diagram of FIG. A pressure controller unit 5 for controlling pressure and a temperature controller unit 6 for controlling temperature are provided.

The pressure comparing means 13 inputs the pressure value detected by the pressure sensor 30 and compares it with the set value 14.
As the set value 14, a preset value is stored in the memory. The setting value 14 can be input by an operator using an input means such as a keyboard.

If the input pressure value and the set value are different, the pressure comparing means 13 gives a command to the motor control means 15 so that they match. Motor control means 15
Controls the rotation speed of the drive motor 16 that drives the screw 20b. The pressure in the gear pump 21 can be changed by changing the rotation speed of the screw 20b.
As described above, by controlling the rotation speed of the screw 20b, the pressure inside the gear pump 21 is controlled to be kept constant.

The temperature comparing means 23 inputs the temperature value detected by the temperature sensor 31 and compares it with the set value 24.
As the set value 24, a preset value is stored in the memory. The operator can input the set value 24 by using an input means such as a keyboard.

If the input temperature value is different from the set value, the temperature comparison means 23 gives a command to the temperature control means 25 so that they match. The temperature control means 25 is
The temperature of the heater 26 is controlled. Gear pump 21 and second
The extruder 20 is provided with a pipe 27 for circulating water. The temperature of this circulating water can be controlled by the heater 26. As described above, by controlling the temperature of the water in the pipe, the temperature in the gear pump 21 is controlled to be kept constant. When controlling to lower the temperature, cold water is circulated.

The controller units 5 and 6 can be constructed by utilizing the functions of a computer. Drive motor 16
A control program is used to control the heater 26. That is, the hardware and the software can be combined appropriately. Further, the signals from the pressure sensor 30 and the temperature sensor 31 are A / D converted and then compared with the set values 14 and 24.

By controlling the pressure as described above, the second
Even if the extrusion device 2 is downsized, the second molding die 22
The discharge amount of the strip rubber extruded from the can be stabilized. If the second extrusion device 2 is downsized, the entire equipment can be downsized. Also, the gear pump 21
It also improves the weighing accuracy. Furthermore, the discharge amount is stable even if continuous operation or intermittent operation and stop is repeated. Further, since the pressure inside the gear pump 21 is made constant, the pressure loss at the time of high rotation is reduced. Further, the discharge amount due to the mixing difference of the rubber material becomes constant.

By controlling the temperature as described above, the viscosity of the rubber material in the gear pump 21 becomes stable. Therefore,
The load on the gear 21a and the second molding die 22 is reduced. Further, even if the operation and the stop are intermittently repeated, the fluctuation of the temperature of the rubber is reduced, so that the discharge amount is stabilized. Further, since the temperature variation of the discharged strip rubber is reduced, the physical properties of the rubber are stabilized.

<Other Embodiments> This embodiment is described on the premise of downsizing the second extrusion device, but even in the case of a large device having a sufficient screw length,
The present invention can be applied. The strip rubber extruded and molded is not limited to a specific shape, and the portion of the tire formed using the strip rubber is not limited to a specific location.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first extrusion device and a second extrusion device.

FIG. 2 is a schematic diagram illustrating a system for controlling pressure and temperature inside a gear pump.

FIG. 3 is a diagram showing a structure of a strainer.

[Explanation of symbols]

1st rubber continuous molding machine 2 Second rubber continuous molding device 3 forming drum 5 Pressure controller 6 Temperature controller 13 Pressure comparison means 14 set value 15 Motor control means 16 Drive motor 20 Second extruder 20b screw 20c Supply port (supply unit) 21 gear pump 22 Second molding die 23 Temperature comparison means 24 set value 25 Temperature control means 26 heater 27 piping L screw length D screw outer diameter

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Claims (3)

[Claims] 1. A supply unit for supplying a rubber material which has been previously treated to remove foreign matters in the previous step, an extruder for kneading and supplying the supplied rubber material, and a rubber material supplied from this extruder. Is a control system for controlling a rubber continuous molding device in which a strip pump used for tire molding is continuously extruded from the molding die, which is provided with a gear pump for sending the pressure to the molding die. A pressure sensor, a pressure comparison means for comparing the detected pressure with a set value, and a motor control means for controlling the rotation speed of a motor for driving the screw of the extruder based on the comparison result of the pressure comparison means A control system for a continuous rubber molding device, which is characterized by comprising: 2. A temperature sensor for detecting a temperature inside the gear pump, a temperature comparing means for comparing the detected temperature with a set value, and a temperature inside the gear pump is adjusted based on a comparison result of the temperature comparing means. The control system for a continuous rubber molding device according to claim 1, further comprising a temperature control means. 3. The continuous rubber molding device according to claim 1, wherein the ratio (L / D) of the length L of the screw of the extruder to the outer diameter D is 1 or more and 8 or less. Control system.