Extrusion device

Abstract

Provided is an extrusion device that, while allowing for simplification of configuration, can extrude each of a plurality of extrusion materials simultaneously and all together in a state in which variations in individual physical properties thereof are suppressed. An extrusion device (1) comprises: cylinders (22) that each have a space (R2) in which a screw (23) is accommodated; a plurality of operating pins (6) that can be moved out of and into the space (S22); and a plurality of actuators (5) that activate the plurality of operating pins (6). The actuators (5) are individually disposed at positions on an outer surface of the cylinder (22) so as to correspond respectively to the plurality of operating pins (6). A plurality of the cylinders (22) are disposed so that downstream ends of the cylinders (22) merge at a single shared discharge port (A2). The plurality of actuators (5) are each disposed in a region on the outer surface of the cylinder (22), within a range (R1) of a prescribed distance from the upstream end to the downstream end of the cylinder (22), where the actuator (5) will not interfere with the surrounding area.

Description

Extrusion Equipment

[0001] This application claims priority to Japanese Patent Application No. 2023-202171, filed on November 29, 2023, the entire contents of which are incorporated herein by reference.

[0002] Known conventional extrusion devices include screw extruders or rubber extrusion devices that have a cylinder housing a screw, with multiple pins attached to some of the pins, and that detect information about the extrusion material from sensors attached to the multiple pins to control the movement of the multiple pins or the rotation speed of the screw (see, for example, Patent Documents 1 to 3).These conventional extrusion devices can produce desired extrusion-molded products with reduced variation in physical properties.

[0003] Japanese Patent Laid-Open No. 09-277353 Japanese Patent Laid-Open No. 2019-081287 Japanese Patent Laid-Open No. 2019-081286

[0004] However, the conventional extrusion device described above cannot simultaneously extrude multiple extrusion materials while suppressing variations in their individual physical properties. In addition, since the actuators that operate the pins are provided on the outer circumferential surface of the cylinder, when multiple cylinders are joined at a single outlet, the arrangement of the actuators that extrude the pins becomes complicated.

[0005] An object of the present invention is to provide an extrusion device that can simultaneously extrude a plurality of extrusion materials at once while suppressing variations in the individual physical properties, while simplifying the configuration.

[0006] (1) An extrusion device according to the present invention includes a cylinder having an internal space in which a screw is housed, a plurality of actuating pins that can be inserted and removed from the internal space, and a plurality of actuators that actuate the actuating pins, each of which is provided on the outer surface of the cylinder so as to correspond to a respective one of the actuating pins, the cylinders being arranged such that their downstream ends join a common outlet, and each of the actuators being located on the outer surface of the cylinder within a predetermined distance from the upstream end of the cylinder toward the downstream end of the cylinder, where the actuator does not interfere with the surrounding actuator. The extrusion device according to the present invention can extrude a plurality of extrusion materials simultaneously and at one time while minimizing variations in the individual physical properties, while simplifying the configuration.

[0007] (2) The extrusion device of (1) above preferably includes a fixed pin protruding into the internal space in a downstream region of the outer surface of the cylinder excluding the region. In this case, in addition to the provision of an actuating pin on the upstream side that can be inserted into and removed from the internal space of the cylinder, more efficient stirring is possible over a wider range of the internal space of the cylinder, thereby further reducing the variation in physical properties. This simplifies the configuration and allows multiple extrusion materials to be extruded simultaneously and at one time with the variation in their individual physical properties further reduced.

[0008] (3) In the extrusion device of (1) or (2), it is preferable that the actuator controls the extension and retraction of the actuating pin based on at least one of the pressure and temperature of the internal space. In this case, the extrusion material fed into the cylinder is effectively stirred under appropriate pressure and temperature, thereby simplifying the configuration and enabling multiple extrusion materials to be extruded simultaneously and at one time with reduced variation in their individual physical properties.

[0009] (4) In the extrusion device according to (3) having the configuration according to (2), the fixing pin preferably includes the sensor for detecting at least one of the pressure and the temperature of the internal space. In this case, the sensor for detecting the state of the internal space of the cylinder is efficiently arranged in the internal space of the cylinder, thereby improving the degree of freedom in the layout of the internal space of the cylinder.

[0010] According to the present invention, an extrusion device can be provided that has a simplified configuration and can simultaneously extrude multiple extrusion materials while suppressing variations in the individual physical properties.

[0011] 1 is a schematic plan view of an extrusion device according to an exemplary embodiment of the present invention;

[0023] FIG. 2 is a perspective view, partially in cross section, of a portion of one of a plurality of material supply units that is a component of the extrusion device of FIG. 1;

[0024] FIG. 3 is a cross-sectional view of an actuator provided in the material supply unit of FIG. 2;

[0025] FIG. 4 is an enlarged view of an area X of FIG. 1;

[0012] An extrusion device according to one embodiment of the present invention will be described below with reference to the drawings. In the following description, the terms "upstream" and "downstream" refer to the direction in which the extrusion material is fed (the direction in which the extrusion material flows). In the following description, the extrusion material will be exemplified as unvulcanized rubber, and the extrusion-molded product will be exemplified as a sheet-shaped unvulcanized rubber sheet in which multiple layers of extrusion material are laminated.

[0013] In FIG. 1 , reference numeral 1 denotes an extrusion device according to one embodiment of the present invention. In this embodiment, the extrusion device 1 includes a material supply section 2, an extrusion die 3, and a control section 4. The extrusion device 1 includes a plurality of material supply sections 2. The downstream sides of the material supply sections 2 each merge into an extrusion die 3. In this embodiment, the extrusion die 3 includes a head 3a to which the downstream end of the material supply section 2 is connected, a die holder 3b attached to the head 3a, and a die 3c attached to the die holder 3b. The die 3c has an outlet A2 that communicates with the material supply section 2. The extrusion device 1 according to this embodiment includes four material supply sections 2. However, the extrusion device 1 may include two or more material supply sections 2.

[0014] The material supply unit 2 includes a material input unit 21 having an input port A1 through which the extrusion material M is input, a cylinder 22 having an internal space S2 communicating with the input port A1 of the material input unit 21, a screw 23 rotatably housed in the internal space S2 of the cylinder 22, and a drive unit 24 for rotating the screw 23. The extrusion material M input from the material input unit 21 is sent from the upstream side to the downstream side of the cylinder 22 by rotation of the screw 23. Each of the internal spaces S2 of the multiple cylinders 22 merges into a common discharge port A2. The drive unit 24 rotates the screw 23 based on commands from the control unit 4. The control unit 4 controls the rotation speed and number of revolutions of the screw 23 based on input information from an external device. In this embodiment, the screw 23 is connected to the drive unit 24. In this embodiment, the drive unit 24 is a motor. The control unit 4 is a combination of a computer, such as a personal computer, and a programmable logic controller (PLC).

[0015] The material supply unit 2 further includes a plurality of actuators 5 on the outer peripheral surface of the cylinder 22 (however, in FIG. 1 , only one actuator 5 is illustratively labeled with a reference numeral). In this embodiment, the material supply unit 2 has a single circumferential row of actuators, in which a plurality of actuators 5 are arranged at intervals in the circumferential direction around the axis O of the cylinder 22. In this embodiment, the circumferential row of actuators is arranged at intervals in the direction in which the axis O of the cylinder 22 extends (hereinafter also referred to as the "axial direction"). That is, in this embodiment, a plurality of actuators 5 arranged at intervals in the circumferential direction are arranged at intervals in the axial direction on the outer peripheral surface of the cylinder 22. In this embodiment, four actuators 5 are arranged concentrically at intervals in the circumferential direction on the outer peripheral surface of the cylinder 22. In addition, in this embodiment, the four actuators 5 arranged concentrically in the axial direction on the outer peripheral surface of the cylinder 22 are arranged at intervals on a straight line along the axial direction. That is, in this embodiment, four circumferential rows of actuators, each consisting of four actuators 5, are arranged at intervals in the axial direction for each of the four cylinders 22. However, this arrangement and number of the actuators 5 are merely exemplary and can be changed as appropriate.

[0016] FIG. 2 is a schematic partial cross-sectional view of the material supply unit 2. As shown in FIG. 2, in this embodiment, the screw 23 includes a shaft 23a extending along the axis O and a screw body 23b spirally disposed on the outer circumferential surface of the shaft 23a. In this embodiment, the shaft 23a of the screw 23 is connected to an output rotation shaft (not shown) of the drive unit 24. The material supply unit 2 includes an actuation pin 6 at a position corresponding to the actuator 5. In this embodiment, the actuator 5 is disposed radially outward (perpendicular to the axial direction) across the cylinder 22, in a position aligned with the actuation pin 6. In this embodiment, the actuation pin 6 protrudes radially inward (perpendicular to the axial direction) toward the axis O. The actuation pin 6 can be operated by the actuator 5, as described below.

[0017] Fig. 3 schematically shows the actuator 5 provided in the material supply unit 2. In this embodiment, the actuator 5 is attached to the outer surface of the cylinder 22 via a bracket 8. In Fig. 3, the left side of the drawing shows an actuating pin 6 being pushed into the internal space S2 of the cylinder 22 by the actuator 5 corresponding to that actuating pin 6. In addition, the right side of the drawing shows another actuating pin 6 being retracted from the internal space S2 of the cylinder 22 into the interior of the cylinder 22 by the actuator 5 corresponding to that actuating pin 6.

[0018] The actuator 5 can move the actuating pin 6 in and out of the internal space S2 of the cylinder 22 based on a command from the control unit 4. For example, the actuating pin 6 can move in and out of the internal space S2 of the cylinder 22 even when the internal space S2 of the cylinder 22 contains the extrusion material M. Here, the movement of the actuating pin 6 in and out is not limited to the on-off control of two types of protrusion lengths: a maximum protrusion length, which is the length of the actuating pin 6 protruding from the inner circumferential surface of the cylinder 22 (hereinafter also referred to as the "protrusion length"), and a minimum protrusion length, which is the minimum protrusion length of the actuating pin 6 (for example, when the tip of the actuating pin 6 is below the inner circumferential surface of the cylinder 22, i.e., zero). In this embodiment, the protrusion length of the actuating pin 6 can be finely adjusted based on a command from the control unit 4. That is, in this embodiment, "controlling the actuating pin 6 in and out" means not simply moving the actuating pin 6 in and out, but also controlling the protrusion length of the actuating pin 6 (including when the protrusion length is zero).

[0019] In this embodiment, the actuating pin 6 is attached to a lifting rod 5a of the actuator 5. The lifting rod 5a can be raised and lowered in response to commands from the control unit 4. This allows the actuator 5 to move the actuating pin 6 in and out of the internal space S2 of the cylinder 22 based on input information from the outside via the control unit 4. In this embodiment, the actuator 5 is a hydraulic cylinder. The lifting rod 5a is a piston rod of the hydraulic cylinder. The piston rod can be raised and lowered by hydraulic pressure in response to commands from the control unit 4. In this case, in this embodiment, the actuating pin 6 can be moved in and out of the internal space S2 of the cylinder 22 in response to hydraulic pressure controlled based on input information from the outside.

[0020] Variations in the physical properties (e.g., viscosity) of the extrusion material M can be controlled, for example, by adjusting the rotation speed of the screw 23 and the protruding length of the actuating pin 6. Specifically, the rotation speed of the screw 23 and the protruding length of the actuating pin 6 are controlled to appropriate values ​​based on information such as pressure and temperature. As a result, the extrusion material M introduced from the material introduction section 21 is conveyed toward the extrusion die 3 while being uniformly stirred in the internal space S of the cylinder 22. By uniformly stirring the extrusion material M, variations in the physical properties (e.g., viscosity) of the extrusion material M are reduced. Therefore, extrusion material M with uniform physical properties is extruded as an extrusion molded product from the discharge port A2 of the extrusion die 3. This allows, for example, an extrusion molded product with a uniform cross-sectional shape to be obtained, with reduced variations in cross-sectional shape that occur after extrusion molding.

[0021] For example, if the extrusion material M fed into the extrusion device 1 is unvulcanized rubber, variations in the physical properties of the unvulcanized rubber will cause variations in the amount of unvulcanized rubber extruded (amount of rubber extruded per unit time) that is extruded from the discharge outlet A2 of the extrusion device 1, or will cause variations in the degree of die swelling (expansion) of the unvulcanized rubber extruded from the discharge outlet A2.

[0022] As described above, variations in the discharge amount of unvulcanized rubber and variations in the degree of die swelling can be controlled, for example, by adjusting the rotation speed of the screw 23 and the protruding length of the actuating pin 6. Therefore, by appropriately controlling these, for example, the cross-sectional shape of the unvulcanized rubber discharged from the discharge port A2 can also be controlled to an appropriate cross-sectional shape.

[0023] However, when there is only one material supply unit 2, it may not be possible to simultaneously extrude multiple extrusion materials M at once while suppressing variations in the physical properties of each material. For example, with only one material supply unit 2, it is difficult to extrude a laminated rubber in which multiple types of unvulcanized rubber are connected together.

[0024] In contrast, in the extrusion device 1 according to the present embodiment, as shown in FIG. 1 , multiple material supply sections 2 are joined together at a single common discharge outlet A2. As a specific example, when extrusion molding is performed using several types of extrusion materials M in a layered state, the multiple material supply sections 2 leading to the single common discharge outlet A2 are joined together by varying the heights of the multiple material supply sections 2. This allows multiple extrusion materials M with reduced variations in physical properties to be supplied in a layered state to the single common discharge outlet A2. Therefore, multiple extrusion materials M, each with uniform physical properties, are extruded simultaneously from the discharge outlet A2 in a layered state with uniform physical properties.

[0025] Furthermore, as in the example where unvulcanized rubber is used as the extrusion material M, the effect of suppressing variations in the discharge amount and the effect of suppressing variations in the degree of die swelling increase with the number of actuating pins 6 (the number of protrusion lengths that can be adjusted). Therefore, the more actuating pins 6 there are, the more likely it is that a laminated unvulcanized rubber sheet with a uniform cross-sectional shape can be extruded.

[0026] However, when the actuators 5 are installed over the entire outer surface of each cylinder 22 of the multiple material supply units 2, adjacent actuators 5 may interfere with each other near the discharge port A2 where the multiple material supply units 2 join. Therefore, in order to have the multiple material supply units 2 join at the extrusion die 3 while leaving the actuators 5 installed over the entire outer surface of each of the multiple cylinders 22, it is necessary to prevent the actuators 5 installed on adjacent cylinders 22 from interfering with each other. This makes handling the cylinders 22 complicated, and as a result, the configuration of the extrusion device becomes complicated.

[0027] On the other hand, it was found that the effect of suppressing the above-mentioned variations was greater when the protrusion length of the actuating pin 6 installed in the region on the inlet A1 side was adjusted than when the protrusion length of the actuating pin 6 installed in the region on the outlet A2 side was adjusted. That is, it was found that focusing on adjusting the protrusion length of the actuating pin 6 installed in the upstream region of the cylinder 22 was more effective in suppressing variations than focusing on adjusting the protrusion length of the actuating pin 6 installed in the downstream region of the cylinder 22. Therefore, even when there are space constraints on the outer surface of the downstream region of the cylinder 22, as in this embodiment, arranging the actuating pin 6 (actuator 5) on the outer surface of the upstream region of the cylinder 22 can achieve a significant effect in suppressing variations.

[0028] Therefore, in the extrusion device 1 according to the present embodiment, as shown in Fig. 1, each of the multiple actuators 5 is disposed in a region R1 on the outer surface of the cylinder 22 within a predetermined distance from the upstream end of the cylinder 22 toward the downstream end of the cylinder 22, where the actuators 5 do not interfere with the surroundings of the actuator 5. Here, interference refers to a state in which a given actuator 5 cannot be installed due to overlapping with surrounding objects (e.g., other actuators 5 or cylinders 22). As shown in Fig. 1, it is preferable that the actuators 5 do not come into contact with each other. However, as long as there is no problem in placing the actuators 5 on the outer surface of the cylinder 22, some degree of contact with each other is acceptable. This allows the actuators 5 provided in each material supply unit 2 to avoid interference with each other, and multiple extrusion materials M can be extruded simultaneously and at one time with reduced variation in their individual physical properties.

[0029] A specific example of the predetermined distance is, when extruding laminated unvulcanized rubber for automobile tires, a region including positions where 80% of the actuating pins 6 are located, counting from the front row on the upstream side of the cylinder 22, of the total number of actuators 5 arranged in the axial direction, when assuming that a plurality of actuators 5 are arranged at equal intervals across the entire axial direction between the upstream and downstream sides of the cylinder 22. In this case, for example, it is possible to avoid a situation where two actuators 5 provided in two adjacent material supply units 2 interfere with each other at downstream positions. This simplifies the handling of the plurality of cylinders 22, resulting in a simpler configuration of the extrusion device.

[0030] Therefore, according to the extrusion device 1 of this embodiment, each of the multiple actuators 5 is arranged in a region R1 on the outer surface of the cylinder 22 within a predetermined distance from the upstream end of the cylinder 22 toward the downstream end of the cylinder 22, where the actuator 5 does not interfere with the surrounding area of ​​the actuator 5. This simplifies the configuration and allows each of the multiple extrusion materials to be extruded simultaneously and at once, with variations in their individual physical properties suppressed.

[0031] 4, the extrusion device 1 according to this embodiment is provided with a plurality of fixed pins 7 that protrude into the internal space S2 of the cylinder 22 in a downstream region R2 excluding the region R1 on the outer surface of the cylinder 22. The fixed pins 7 are fixed to the inner circumferential surface of the cylinder 22. That is, no accessories such as an actuator 5 for operating the fixed pins 7 are connected to the fixed pins 7. In this embodiment, the fixed pins 7 protrude radially inward toward the axis O.

[0032] When the fixed pins 7 are provided as in this embodiment, in combination with the actuating pins 6 provided upstream and retractable into the internal space S2 of the cylinder 22, more efficient stirring is possible over a wider range of the internal space S of the cylinder 22, thereby further reducing variations in physical properties. This simplifies the configuration and allows multiple extrusion materials M to be extruded simultaneously and at once with reduced variations in their individual physical properties. In this embodiment, the multiple fixed pins 7 are arranged on the inner surface of the cylinder 22 in the same arrangement as the actuating pins 6 (actuators 5). For example, the fixed pins 7 are arranged circumferentially at intervals so as to be aligned with the actuating pins 6 in the circumferential direction. For example, only four fixed pins 7 arranged concentrically in the axial direction of the inner surface of the cylinder 22 may be provided. However, the axial arrangement of the fixed pins 7 may be appropriately set depending on the range of region R1. For example, the fixed pins 7 may be arranged in region R1 instead of region R2 along with region R2. The fixed pins 7 may also be arranged in a downstream region other than region R2. That is, the arrangement and number of the fixing pins 7 can be changed as appropriate.

[0033] In the extrusion device 1 of this embodiment, the actuator 5 controls the extension and retraction of the actuating pin 6 based on at least one of the pressure and the temperature of the internal space S2 of the cylinder 22.

[0034] In this embodiment, the control unit 4 receives the pressure and temperature of the internal space S2 as external input information, and defines these pressure and temperature as the pressure and temperature of the extrusion material M contained in the internal space S2, respectively. The control unit 4 then calculates, for example, the viscosity of the extrusion material M contained in the internal space S2 based on at least one of the pressure and temperature of the internal space S2. Furthermore, in this embodiment, the control unit 4 calculates an appropriate rotation speed (rotational speed) of the screw 23 based on the calculated viscosity so that the extrusion material M contained in the internal space S2 is uniformly stirred. Furthermore, in this embodiment, the control unit 4 issues a command to the drive unit 24 to control the drive unit 24 so that the screw 23 rotates at the above-mentioned rotation speed. Specifically, the control unit 4 issues a command to the drive unit 24 to control the rotation of the motor. The rotation speed of the screw 23 is thereby controlled so that the extrusion material M contained in the internal space S2 of the cylinder 22 has uniform physical properties.

[0035] Furthermore, in this embodiment, the control unit 4 calculates an appropriate protrusion length of the actuating pin 6 based on the calculated viscosity so that the extrusion material M contained in the internal space S2 is stirred more uniformly. Furthermore, in this embodiment, the control unit 4 issues a command to the actuator 5 to control the actuator 5 so that the actuating pin 6 protrudes to the above-mentioned protrusion length. As a specific example, the control unit 4 issues a command to the actuator 5 to control a pressure regulating valve (not shown) of the hydraulic cylinder. In this way, the protrusion length of the actuating pin 6 is controlled so that the extrusion material M contained in the internal space S2 of the cylinder 22 has more uniform physical properties.

[0036] In the present embodiment, when the extension and retraction of the actuating pin 6 is controlled based on at least one of the pressure and temperature of the internal space S2, the extrusion material M fed into the cylinder 22 is effectively stirred under appropriate pressure and temperature, thereby simplifying the configuration and enabling each of the multiple extrusion materials M to be extruded simultaneously and at once with reduced variation in their individual physical properties.

[0037] In the extrusion device 1 according to this embodiment, the fixing pin 7 is provided with a sensor that detects at least one of the pressure and the temperature of the internal space S2.

[0038] The pressure sensor and temperature sensor may be, for example, existing sensors that can be installed on the outer surface of the fixed pin 7 or inside the fixed pin 7. The control unit 4 can predict the cross-sectional shape after extrusion molding by using a machine learning system or the like based on data from at least one of the pressure sensor and the temperature sensor. In this case, the rotation speed of the screw 23 and the protruding length of the actuating pin 6 can be derived so that the cross-sectional shape after extrusion molding is controlled to be the target cross-sectional shape. However, the pressure sensor may be installed in a location other than the fixed pin 7 as long as it can detect the pressure in the internal space S2 of the cylinder 22. For example, the pressure sensor may be installed in the actuating pin 6 instead of or in addition to the fixed pin 7. Similarly to the pressure sensor, the temperature sensor may also be installed in a location other than the fixed pin 7 as long as it can detect the temperature in the internal space S2 of the cylinder 22.

[0039] When a sensor is placed on the fixing pin 7 as in this embodiment, the sensor for detecting the state of the internal space S2 of the cylinder 22 is efficiently placed in the internal space S2 of the cylinder 22, thereby improving the freedom of layout within the internal space S2 of the cylinder 22.

[0040] The above is an exemplary embodiment of the present invention. Therefore, the present invention is not limited to the above embodiment and can be modified in various ways within the scope of the claims. For example, the actuators 5 (actuator pins 6) can be controlled in array units arranged concentrically in the circumferential direction (actuator circumferential array units). The actuators 5 can also be controlled in array units arranged axially (actuator axial array units). Furthermore, the actuators 5 can be controlled individually. That is, multiple actuators 5 can be freely controlled individually. In this embodiment, the extrusion material M is unvulcanized rubber. However, various materials that require stirring (mixing) can be used as the extrusion material M. Furthermore, the multiple extrusion materials M can be the same or different. Input information to the control unit 4 includes the pressure and temperature of the internal space S2 of the cylinder 22, as well as the shape (die shape) of the discharge port A2 of the extrusion die 3 and the number of actuating pins 6 and fixed pins 7.

[0041] 1: Extrusion device, 2: Material supply section, 21: Material input section, 22: Cylinder, 23: Screw, 23a: Screw shaft, 23b: Screw body, 24: Drive section, 3: Extrusion die, 3a: Head, 3b: Die holder, 3c: Die, 4: Control section, 5: Actuator, 5a: Lifting rod, 6: Actuating pin, 7: Fixing pin, 8: Bracket, A1: Input port, A2: Discharge port (squeeze), M: Extrusion material, S2: Internal space of cylinder

Claims

1. An extrusion device comprising: a cylinder having an internal space that accommodates a screw; a number of actuating pins that can be inserted and removed into the internal space; and a number of actuators that actuate the number of actuating pins, each of which is provided at a position on the outer surface of the cylinder corresponding to a respective one of the number of actuating pins; wherein the cylinders are arranged in a plurality of positions so that their downstream ends join a single common discharge outlet; and wherein each of the actuators is arranged in an area of ​​the outer surface of the cylinder within a predetermined distance from the upstream end of the cylinder toward the downstream end of the cylinder, where the actuator does not interfere with the surrounding area of ​​the actuator.

2. The extrusion device according to claim 1, further comprising a fixing pin protruding into said internal space in a downstream area excluding said area of ​​the outer surface of said cylinder.

3. The extrusion device according to claim 1 or 2, wherein the actuator controls the extension and retraction of the actuating pin based on at least one of the pressure and temperature of the internal space.

4. An extrusion device according to claim 3 which recites claim 2, wherein the fixing pin is provided with the sensor for detecting at least one of the pressure and the temperature of the internal space.

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