JP6954006B2 - Rubber extruder and method - Google Patents

Description

The present invention relates to a rubber extruder and a method, and more particularly to a rubber extruder and a method capable of more accurately and stably obtaining an unvulcanized rubber extrusion having a desired range of plasticity.

When manufacturing rubber products such as tires, there is an extrusion process using a rubber extrusion device. Inside the cylinder of the rubber extruder, the unvulcanized rubber material is kneaded while being sent toward the front of the cylinder by a rotating screw, and the unvulcanized rubber extruded product molded into a predetermined shape is extruded from the extrusion port. .. In the rubber extruder, in order to obtain a rubber extrusion having a desired plasticity (viscosity), the internal pressure of the cylinder, the temperature of the rubber extrusion at the extrusion port, and the like are controlled.

As a rubber extruder, a device with a pin having a pin protruding inside a cylinder is known. In this rubber extruder, the unvulcanized rubber material kneaded between the screw and the inner peripheral surface of the cylinder is dispersed and mixed by the pins, so that the kneading efficiency is improved.

A method of obtaining a rubber extrusion having a desired viscosity by using a rubber extrusion device with a pin has been proposed (see Patent Document 1). In the method proposed in Patent Document 1, the viscosity and temperature of the rubber material inside the cylinder are detected by a sensor arranged at the front end of the cylinder, and the insertion depth of the pin into the cylinder is controlled based on this detection data. (See Patent Document 1). In this method, even if the insertion depth of the pin is controlled based on the detection data of the sensor, the rubber material that has already been sent to the front end of the cylinder cannot be sufficiently kneaded, so the viscosity is adjusted. Is impossible to do. Therefore, there is room for improvement in obtaining a rubber extrusion having a desired viscosity accurately and stably.

Japanese Unexamined Patent Publication No. 9-277353

An object of the present invention is to provide a rubber extruder and a method capable of obtaining an unvulcanized rubber extrusion having a desired degree of plasticity more accurately and stably.

In order to achieve the above object, the rubber extruder of the present invention includes a cylindrical cylinder, a screw internally provided in the cylinder, and a pin protruding inside the cylinder and having a variable protruding length. In the rubber extruder, the cylinder is arranged in a section in the longitudinal direction of the cylinder between the rubber material inlet of the cylinder and the front end of the cylinder at intervals in the longitudinal direction of the cylinder, and is not kneaded inside the cylinder. It has a plurality of sensors that detect at least one of the pressure and temperature of the vulgarized rubber material, and a control unit that inputs detection data from each of the sensors, and each of the sensors has a screw shaft that constitutes the screw. The pin is arranged in a section of 10% of the size of the gap on the screw shaft side of the gap between the outer peripheral surface of the cylinder and the inner peripheral surface of the cylinder, and in the section in the longitudinal direction of the cylinder between the sensors. Is arranged, the target value for the detection data of each of the sensors is stored in the control unit, and the detection data and the detection data are stored so as to bring the detection data closer to the target value. It is characterized in that the protruding length of the pin is controlled by the control unit based on each of the target values.

In the rubber extrusion method of the present invention, the pin is charged into the inside of the cylinder from the rubber material input port by rotating a screw provided inside the cylindrical cylinder in which the pin protrudes with a variable protrusion length. In a rubber extrusion method in which an unvulcanized rubber material is kneaded while being fed toward an extrusion port in front of the cylinder and extruded as a rubber extrusion from the extrusion port, the rubber material input port and the front end portion of the cylinder A plurality of sensors are arranged at intervals in the longitudinal direction of the cylinder in the section in the longitudinal direction of the cylinder between the sensors, and the pins are arranged in the section in the longitudinal direction of the cylinder between the sensors to form the screw. At least one of the pressure or temperature of the rubber material by each of the sensors arranged in a section of 10% of the size of the gap on the screw shaft side of the gap between the outer peripheral surface of the rubber and the inner peripheral surface of the cylinder. Is detected, the detection data by each of the sensors is input to the control unit, the target value of the detection data of each of the sensors is stored in the control unit, and each of the detection data is stored in each of the control units. It is characterized in that the protrusion length of the pin is controlled by the control unit based on the respective detection data and the respective target value so as to approach the target value.

According to the present invention, at least one of the pressure and the temperature of the unvulcanized rubber material kneaded inside the cylinder is detected by the respective sensors arranged at intervals in the longitudinal direction of the cylinder. Then, since the control unit controls the protrusion length of the pin into the cylinder so that the detection data by each sensor approaches the target value for each detection data stored in advance in the control unit, the cylinder. Compared to the conventional technology that controls the protrusion length of the pin using only the detection data of the sensor placed at the front end of the It will be possible to obtain.

It is explanatory drawing which illustrates the rubber extruder of this invention in a plan view. It is explanatory drawing which illustrates the rubber extruder of FIG. 1 from the side view. It is explanatory drawing which enlarges the inside of the cylinder of FIG. 1, and illustrates by the side view. It is a graph which illustrates the relationship between the detection data of each sensor of FIG. 1 and the target value for each detection data. It is explanatory drawing which illustrates another embodiment of a rubber extruder in a side view. It is explanatory drawing which schematically exemplifies the unit of a sensor and a pin of FIG. It is a graph which illustrates the relationship between the detection data of each sensor of FIG. 5 and the target value for each detection data.

Hereinafter, the rubber extruder and method of the present invention will be described based on the embodiment shown in the figure.

The rubber extruder 1 of the present invention illustrated in FIGS. 1 to 3 extrudes a rubber extruder R2 obtained by kneading an unvulcanized rubber material R1 to a desired degree of plasticity. There is a correlation between the plasticity of the rubber material R1 and the pressure and temperature of the rubber material R1 inside the cylinder 2. Therefore, in the present invention, at least one target value of the pressure or temperature of the rubber material R1 inside the cylinder 2 is set. Then, by bringing the pressure or temperature of the rubber material R1 inside the cylinder 2 close to a target value, a rubber extruded product R2 having a desired degree of plasticity is obtained.

The rubber extruder 1 detects a cylindrical cylinder 2, a screw 4 built in the cylinder 2, a pin 7 protruding inside the cylinder 2, sensors 10a and 10b, and sensors 10a and 10b, respectively. It includes a control unit 9 for sequentially inputting data. A rubber material input port 2a is formed in the upper part on the rear end side of the cylinder 2. A hopper portion 11 is projected from the cylinder 2 so as to surround the rubber material input port 2a.

A head 3 is installed at the tip of the cylinder 2. A die 5 is attached to the head 3. An extrusion port 6 is formed in the die 5. The screw 4 is a plurality of spiral screws arranged with a gap in the axial direction of the screw shaft 4b (longitudinal direction of the cylinder 2) so as not to interfere with the protruding portion 7a of the pin 7 protruding inside the cylinder 2. It has a blade 4a. The screw 4 is rotationally driven by a drive motor 4c arranged behind the cylinder 2. The rotation operation (rotation and rotation stop, rotation speed) of the drive motor 4c is controlled by the control unit 9. The rubber extruder 1 is a uniaxial type, but a biaxial type or the like may be provided by providing a plurality of screws 4.

The pair of sensors 10a and 10b are arranged in the longitudinal section of the cylinder 2 between the rubber material input port 2a of the cylinder 2 and the front end portion of the cylinder 2 at intervals in the longitudinal direction of the cylinder 2. The front end portion of the cylinder 2 is, for example, a range of 10% of the total length of the cylinder 2 on the front end side of the cylinder 2.

In this embodiment, one sensor 10a is attached to one of the plurality of pins 7 arranged at a predetermined position on the rearmost end side of the cylinder 2. The other sensor 10b is attached to one of the plurality of pins 7 arranged at a predetermined position on the frontmost end side of the cylinder 2. The paired sensors 10a and 10b may be arranged at intervals as much as possible in the longitudinal direction of the cylinder 2. The respective sensors 10a and 10b can be directly attached to the cylinder 2 without being attached to the pin 7.

Each of the sensors 10a and 10b detects at least one of the pressure (cylinder internal pressure) or the temperature at the position where the respective sensors 10a and 10b of the unvulcanized rubber material R1 kneaded inside the cylinder 2 are arranged. do. In this embodiment, a pair of sensors 10a and 10b for detecting the pressure of the rubber material R1 are arranged, but a pair of sensors 10a and 10b for detecting the temperature of the rubber material R1 or the pressure and temperature of the rubber material R1. A pair of sensors 10a and 10b for detecting the above can also be provided. The number and position of the sensors 10a and 10b can be appropriately determined.

The pins 7 are arranged in the longitudinal section of the cylinder 2 between the respective sensors 10a and 10b. Each pin 7 penetrates from the outside to the inside of the cylinder 2 and can be moved in the radial direction of the cylinder 2 by the pin driving unit 8. Therefore, the protruding length L (L1, L2) of the protruding portion 7a protruding inside the cylinder 2 of the pin 7 is variable.

In this embodiment, a plurality of columnar pins 7 are arranged at intervals in the longitudinal direction of the cylinder 2. Further, a plurality of pins 7 are arranged at predetermined positions spaced apart from each other in the longitudinal direction of the cylinder 2 at intervals in the circumferential direction of the cylinder 2. For example, 4 to 12 pins 7 are installed at equal intervals in the circumferential direction. As in this embodiment, one sensor 10a is not only attached to one pin 7 of the plurality of pins 7 arranged at a predetermined position on the rearmost end side of the cylinder 2, but also on the rearmost end side. It can also be attached to a plurality of pins 7 arranged at predetermined positions of. The other sensor 10b is not only attached to one of the pins 7 arranged at the predetermined positions on the frontmost end side of the cylinder 2, but also the plurality of pins arranged at the predetermined positions on the frontmost end side. It can also be attached to 7.

The control unit 9 stores target values for detection data of the respective sensors 10a and 10b (detection data at the detection positions of the respective sensors 10a and 10b) according to the composition of the rubber material R1 and the like. This target value is grasped by, for example, conducting a test using the rubber extruder 1 in advance.

Further, the control unit 9 stores correlation data between the protrusion length L of each pin 7 and the plasticity (pressure or temperature) of the kneaded rubber material R1. That is, correlation data indicating how much the plasticity (pressure or temperature) of the rubber material R1 changes when the protrusion length L of each pin 7 is changed is input in advance to the control unit 9. .. This correlation data is also grasped by performing a test using the rubber extruder 1 in advance, for example.

A computer or the like is used as the control unit 9. The control unit 9 operates the pin drive unit 8 to control the protrusion length L of each pin 7 based on the detection data of the respective sensors 10a and 10b and the respective target values. The protrusion length L can be controlled independently for each pin 7, or the protrusion length L can be controlled for each pin 7 at the same predetermined position in the longitudinal direction of the cylinder 2. The pin 7 to which the sensors 10a and 10b are attached basically maintains the protrusion length L at a constant protrusion length L without changing the protrusion length L.

Next, a procedure for extruding the rubber extrusion R2 using the rubber extrusion device 1 will be described.

As illustrated in FIGS. 1 and 2, the unvulcanized rubber material R1 in which the raw rubber contains a non-vulcanized compounding agent or the like is introduced from the rubber material input port 2a into the inside of the cylinder 2 through the hopper portion 11. It is thrown in. The rubber material R1 charged into the inside of the cylinder 2 is kneaded while being sent toward the head 3 (extrusion port 6) inside the cylinder 2 by a screw 4 that rotates at a predetermined rotation speed. The rubber material R1 sent to the head 3 is molded into a predetermined shape from the extrusion port 6 as an unvulcanized rubber extrusion R2 and extruded.

In this extrusion step, as illustrated in FIG. 3, the rubber material R1 is kneaded while adjusting the protrusion length L of each pin 7. By changing the protruding length L of the pin 7, the magnitude of the resistance force received from the pin 7 by the rubber material R1 advancing inside the cylinder 2 toward the extrusion port 6 can be changed. The kneaded state of the rubber material R1 also changes depending on the magnitude of this resistance. Therefore, by appropriately adjusting the protrusion length L of the pin 7, it becomes easy to obtain an appropriate degree of plasticity.

As illustrated in FIG. 4, one sensor 10a sequentially detects the pressure of the rubber material R1 at a predetermined position P1 in the longitudinal direction of the cylinder 2, and this detection data is sequentially input to the control unit 9. The other sensor 10b sequentially detects the pressure of the rubber material R1 at a predetermined position P2 in the longitudinal direction of the cylinder 2, and this detection data is sequentially input to the control unit 9. In FIG. 4, the detection data by the respective sensors 10a and 10b are indicated by black circles, and the respective target values are indicated by white circles.

The control unit 9 compares the input detection data with the target value. When a plurality of sensors 10a are arranged at the same cylinder longitudinal direction position, for example, the average value of the detection data of each sensor 10a is compared with the target value. Similarly, when a plurality of sensors 10b are arranged at the same cylinder longitudinal direction position, for example, the average value of the detection data of each sensor 10b is compared with the target value. As a result of comparison, if there is a difference between the detection data and the target value, the correlation data between the protrusion length L of each pin 7 and the pressure of the kneaded rubber material R1 so that the detection data approaches the target value. Based on the above, the pin drive unit 8 is operated to control the required protrusion length L of the pin 7. As a result, the plasticity of the rubber extruded product R2 at the extrusion port 6 is set within a desired range.

When the pressure of the rubber material R1 is changed to be larger, the protrusion length L is controlled for more pins 7, and the protrusion length L is controlled to be larger. When the pressure of the rubber material R1 is made smaller, for example, the protrusion length L is controlled for a smaller number of pins 7, and the protrusion length L is controlled to be smaller. Similarly, when the temperature of the rubber material R1 is detected by the sensors 10a and 10b, the plasticity of the rubber extruded product R2 at the extrusion port 6 is set within a desired range by controlling the protrusion length L of the pin 7.

According to the present invention, the protrusion length L of the pin 7 is controlled by using the detection data of the sensors 10a and 10b arranged at intervals in the longitudinal direction of the cylinder 2. Therefore, even when the physical properties of the rubber material R1 charged into the cylinder 2 vary widely, the protrusion length L of the pin 7 can be controlled based on the detection data of the sensor 10a on the upstream side. The plasticity (pressure) of the rubber material R1 can be corrected so as to approach the target value from an earlier stage. Then, by controlling the protrusion length L of the pin 7 based on the detection data of the sensor 10a on the upstream side and the sensor 10b on the downstream side, the plasticity of the rubber material R1 at the predetermined position P2 on the downstream side is made more accurate. You can get close to the target value well. Therefore, as compared with the conventional technique of controlling the protrusion length of the pin using only the detection data of the sensor arranged at the front end of the cylinder, the rubber extruded product R having a desired degree of plasticity can be more accurately and stably produced. Obtainable.

When the plasticity of the kneaded rubber material R1 is small (when the plasticization is insufficient), in the same cylinder longitudinal position, the vicinity of the outer peripheral surface of the screw shaft 4b is closer than the vicinity of the inner peripheral surface of the cylinder 2. The inventor of the present application has found that the variation of the detected data becomes large. Therefore, if the variation of the detection data over time in the vicinity of the outer peripheral surface of the screw shaft 4b is small, it can be determined that the rubber material R1 is satisfactorily plasticized. Therefore, it is advisable to increase the protruding length L of the pin 7 to which the sensors 10a and 10b are attached as much as possible to acquire the detection data in the vicinity of the outer peripheral surface of the screw shaft 4b. For example, the sensors 10a and 10b may be arranged in a section of 10% of the size of the gap on the screw shaft 4b side of the gap between the outer peripheral surface of the screw shaft 4b and the inner peripheral surface of the cylinder 2.

In another embodiment of the rubber extruder 1 illustrated in FIG. 5, more sensors 10a, 10b, 10c, and 10d are spaced in the longitudinal direction of the cylinder 2 as compared with the previous embodiment, and the length of the cylinder 2 is long. They are arranged at predetermined positions P1, P2, P3, and P4 in the direction, respectively. The control unit 9 has detection data of the respective sensors 10a, 10b, 10c, and 10d (detection positions P1, P2, P3, and P4 of the respective sensors 10a, 10b, 10c, and 10d according to the composition of the rubber material R1 and the like. The target value for the detection data) is stored. Other configurations are substantially the same as in the previous embodiment, and the various specifications described in the previous embodiment can be applied to this embodiment as well.

In this embodiment, as illustrated in FIG. 6, the sensor 10a and the sensor 10b are paired, the sensor 10b and the sensor 10c are paired, and the sensor 10c and the sensor 10d are paired. The unit U1 is composed of a pair of sensors 10a and 10b and pins 7 arranged in a longitudinal section of the cylinder 2 between the sensors 10a and 10b. Similarly, the unit U2 is composed of a pair of sensors 10b and 10c and pins 7 arranged in a longitudinal section of the cylinder 2 between the sensors 10b and 10c. Similarly, the unit U3 is composed of a pair of sensors 10c and 10d and pins 7 arranged in a longitudinal section of the cylinder 2 between the sensors 10c and 10d. That is, the previous embodiment has only one unit composed of a pair of sensors 10a and 10b and pins 7 arranged in a longitudinal section of the cylinder 2 between the sensors 10a and 10b. However, in this embodiment, it has a plurality of units U1, U2, and U3 arranged in the longitudinal direction of the cylinder 2.

In this embodiment, in the units U1 and U2 arranged adjacent to each other in the longitudinal direction of the cylinder 2, the sensors 10b arranged at positions adjacent to the units U1 and U2 are the respective units U1 and U2. It is shared as a component of. Similarly, sensors 10c arranged at positions adjacent to the units U2 and U3 are shared as constituent members of the units U2 and U3, respectively.

In this embodiment, in one unit U1, at least one of the pressure and the temperature of the rubber material R1 is sequentially detected by the respective sensors 10a and 10b, and the detection data by the respective sensors 10a and 10b are sequentially detected by the control unit 9. input. As illustrated in FIG. 7, the control unit 9 brings the respective detection data closer to the target values for the detection data of the respective sensors 10a and 10b stored in the control unit 9 in advance. And the protrusion length L of the pin 7 of the unit U1 is controlled based on each target value. Similar to the unit U1, the other units U2 and U3 also control the protrusion length L of the pin 7 of each unit so that the detection data in the section of each unit approaches the target value for each unit. do. In FIG. 7, the detection data by the respective sensors 10a, 10b, 10c, and 10d are indicated by black circles, and the respective target values are indicated by white circles. As a result, the plasticity of the rubber extruded product R2 at the extrusion port 6 is set within a desired range.

In this embodiment, the section in the longitudinal direction of the cylinder 2 that controls the protrusion length L of the pin 7 is subdivided as compared with the previous embodiment. Therefore, the plasticity of the rubber material R1 can be more accurately approached to the target value with respect to the total length of the cylinder 2. Along with this, it becomes more and more advantageous to obtain the extruded rubber R2 having a desired degree of plasticity accurately and stably.

1 Extruder 2 Cylinder 2a Rubber material input port 3 Head 4 Screw 4a Screw blade 4b Screw shaft 4c Drive motor 5 Die 6 Extrusion port 7 Pin 7a Protruding part 8 Pin Drive unit 9 Control unit 10a, 10b, 10c, 10d Sensor 11 Hopper Parts U1, U2, U3 Unit R1 Unvulcanized rubber material R2 Rubber extruded product

Claims (4)

In a rubber extruder provided with a tubular cylinder, a screw internally provided in the cylinder, and a pin protruding inside the cylinder and having a variable protruding length.
An unvulcanized rubber material that is arranged at intervals in the longitudinal direction of the cylinder and kneaded inside the cylinder in a section in the longitudinal direction of the cylinder between the rubber material input port of the cylinder and the front end portion of the cylinder. It has a plurality of sensors that detect at least one of the pressure or temperature of the screw, and a control unit that inputs detection data by the respective sensors, and each of the sensors has an outer peripheral surface of a screw shaft constituting the screw and the sensor. The pin is arranged in a section of 10% of the size of the gap on the screw shaft side of the gap with the inner peripheral surface of the cylinder, and the pin is arranged in the section in the longitudinal direction of the cylinder between the respective sensors. The control unit stores target values for the detection data of each sensor, and each detection data and each target value so as to bring each detection data closer to each target value. A rubber extrusion device characterized in that the protruding length of the pin is controlled by the control unit based on the above. The rubber extrusion according to claim 1, wherein a plurality of units composed of the pins arranged in a section in the longitudinal direction of the cylinder between each of the sensors and the respective sensors are arranged in the longitudinal direction of the cylinder. Device. The second aspect of claim 2, wherein in the units arranged adjacent to each other in the longitudinal direction of the cylinder, the sensors arranged at positions adjacent to each other are shared as constituent members of the respective units. Rubber extruder. The unvulcanized rubber material charged into the inside of the cylinder from the rubber material input port is rotated by rotating the screw installed in the cylindrical cylinder in which the pin projects with a variable protrusion length. In a rubber extrusion method in which kneading is performed while feeding toward the extrusion port in front of the cylinder and the rubber is extruded from the extrusion port as a rubber extrusion.
A plurality of sensors are arranged in the section in the longitudinal direction of the cylinder between the rubber material input port and the front end portion of the cylinder at intervals in the longitudinal direction of the cylinder , and the sensor is arranged in the section in the longitudinal direction of the cylinder between the sensors. Each pin is arranged in a section of 10% of the size of the gap on the screw shaft side of the gap between the outer peripheral surface of the screw shaft constituting the screw and the inner peripheral surface of the cylinder. At least one of the pressure and the temperature of the rubber material is detected by the sensor, the detection data by each of the sensors is input to the control unit, and the control unit receives a target value for the detection data of each of the sensors. To store and control the protrusion length of the pin by the control unit based on the detection data and the target value so that the detection data approaches the target value. A rubber extrusion method characterized by.

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