JP2012086423A - Injection molding machine and method of manufacturing molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely control the temperature of a molding material injected into the mold from a flow passage of a nozzle by easily changing the cross-section of the flow passage of the nozzle.SOLUTION: An injection molding machine 1 is provided with the nozzle 30 having a throttle part 32 formed in the flow passage 31 and the molding material S is injected into the mold 10 through the flow passage 31 to manufacture the molding. In the injection of the molding material S, the nozzle 30 in the injection molding machine 1 is abutted to the mold 10, the distance between a flow passage adjusting member 50 arranged in the flow passage 31 and the throttle part 32 is changed to control the cross-section area of the flow passage 31 between the throttle part 32 and the flow passage adjusting member 50. In the injection molding machine 1, the molding material S is injected into the mold 10 through the flow passage 31 between the throttle part 32 and the flow passage adjusting member 50.

Description

  The present invention relates to an injection molding machine that injects a molding material from a nozzle into a molding die, and a manufacturing method for producing a molded product by molding the injected molding material in a molding die.

  A molded product made of a molding material such as unvulcanized rubber or resin is manufactured by molding the molding material into a predetermined shape in a molding die such as a mold. As an apparatus for manufacturing this molded product, an injection molding machine for molding a molded product by injecting a molding material into a cavity in a mold has been known (see Patent Document 1).

FIG. 4 is a cross-sectional view of an essential part showing an example of a conventional injection molding machine.
A conventional injection molding machine 100 includes a nozzle 110 for injecting a molding material S (here, rubber) and a molding die 120 as shown in the figure. The injection molding machine 100 brings the nozzle 110 into contact with the molding die 120, injects the molding material S from the nozzle 110 into the cavity 121 of the molding die 120, and molds the molded product P in the cavity 121. In that case, the injection molding machine 100 injects the rubber | gum which is the molding material S from the flow path (injection hole) 111 of the predetermined diameter (for example, 4-10 mm) formed in the nozzle 110. FIG.

  Here, when the rubber passes through the flow path 111 of the nozzle 110, the rubber is heated by heat accompanying friction, resistance, and the like and injected into the mold 120. Therefore, it is necessary for the nozzle 110 to perform an injection test with various changes in the diameter of the flow path 111 in accordance with the molded product P, the type of rubber, and the like, and to select an optimum diameter that can heat the rubber appropriately. However, when the temperature around the injection molding machine 100 changes, the diameter of the nozzle 110 and the temperature and characteristics of the rubber before injection may change, and the temperature of the injected rubber may fluctuate. As a result, the temperature of the rubber rises, so-called rubber scorch occurs, or it becomes difficult for the rubber to be injected from the flow path 111, and there is a possibility that a trouble that the rubber cannot be injected within a predetermined time may occur. Therefore, in the conventional injection molding machine 100, it is necessary to take time and effort to select the injection test and the nozzle 110 in summer and winter, for example, according to changes in the temperature.

  Further, even when the selected nozzle 110 is used, when the molded product P is heated and vulcanized in the mold 120 without the temperature of the injected rubber becoming constant due to the variation in the injection speed and temperature of the rubber. In addition, there is a risk that the degree of vulcanization of the molded product P may vary. Regarding this variation, by using the nozzle 110 having a large diameter, it is possible to prevent the rubber temperature from becoming too high, and to suppress the occurrence of overvulcanization in the molded product P. In addition, the vulcanization time of the molded product P can be avoided by extending the vulcanization time of the molded product P. However, if it does in this way, since the time which manufactures the molded article P becomes long, productivity of the molded article P will become low. Each of the above problems can be solved if the diameter of the nozzle 110 and the cross-sectional area of the flow path 111 can be easily changed without replacing the nozzle 110. However, since the rubber at the time of injection becomes high pressure (for example, 200 MPa or more), it is difficult to realize the nozzle 110 having such a function.

  On the other hand, conventionally, an injection molding machine that controls the temperature of the molten rubber material by providing a rotary valve in the injection path of the molten rubber material and controlling the throttle of the path by the valve is known (Patent Document 2). reference).

  However, in this conventional injection molding machine, the rotary valve is provided on the upstream side relatively far from the nozzle at the tip. For this reason, the temperature of the molten rubber material tends to fluctuate after passing through the throttle of the rotary valve and before being injected from the nozzle. Further, when the temperature of the molten rubber material becomes too high due to the narrowing of the path with the rotary valve, there is a possibility that the molten rubber material will be burned with rubber and the rubber will be clogged between the rotary valve and the nozzle. In this case, it is necessary to disassemble and clean the rotary valve and nozzle, which requires difficult work, and there is a problem that labor and time are wasted. Therefore, in this conventional injection molding machine, it is required to control the temperature of the molten rubber material to be injected with higher accuracy.

JP 2008-55614 A JP 2000-117777 A

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to make it possible to easily change the cross-sectional area of the flow path of the nozzle and to provide a molding material to be injected into the mold from the flow path of the nozzle. It is to control the temperature accurately.

The present invention is an injection molding machine that includes a nozzle having a flow passage for a molding material, and injects the molding material into the mold from the flow passage of the nozzle. A flow path adjusting member that is disposed in the flow path and changes the cross-sectional area of the flow path with the throttle portion in accordance with a change in the distance between the throttle portion and the distance between the throttle portion and the flow path adjusting member And a distance changing means for changing.
The present invention also relates to a method of manufacturing a molded product by manufacturing a molded product by injecting a molding material into a mold from a flow path provided in the nozzle, and molding the nozzle having a throttle portion formed in the flow path. The cross-sectional area of the flow path between the throttle portion and the flow path adjusting member by changing the distance between the flow path adjusting member and the throttle portion disposed in the flow path of the nozzle, and the step of contacting the mold And a step of injecting a molding material into a molding die through a flow path between a throttle part of the nozzle and a flow path adjusting member.

  ADVANTAGE OF THE INVENTION According to this invention, the cross-sectional area of the flow path of a nozzle can be changed easily, and the temperature of the molding material injected into a shaping | molding die from the flow path of a nozzle can be controlled accurately.

It is principal part sectional drawing which shows the injection molding machine of this embodiment. It is sectional drawing which expands and shows the injection head of an injection molding machine. It is sectional drawing which shows the injection head of other embodiment. It is principal part sectional drawing which shows the example of the conventional injection molding machine.

Hereinafter, an embodiment of an injection molding machine and a method of manufacturing a molded product according to the present invention will be described with reference to the drawings.
The injection molding machine according to the present embodiment is an apparatus for manufacturing a molded product (injection molded product), and includes a nozzle having a flow passage for the molding material, and the molding material is injected into the molding die from the flow passage of the nozzle. Is molded. The molding material is a material (injection material) obtained by melting or plasticizing a raw material of a molded product so as to be injection-molded, and is made of, for example, unvulcanized rubber or resin. In the following description, an unvulcanized rubber (hereinafter simply referred to as rubber) is taken as an example of the molding material. That is, the injection molding machine injects a molding material, which is rubber, into a molding die and molds it, and heats (vulcanizes) the rubber to a predetermined vulcanization temperature to produce a rubber molded product.

FIG. 1 is a cross-sectional view of an essential part showing an injection molding machine of the present embodiment. In FIG. 1, a part of the injection molding machine is shown without being cut.
As illustrated, the injection molding machine 1 includes an injection device 2 for injecting a molding material S, a moving device 3 for moving the injection device 2 (schematically shown in FIG. 1 by a two-dot chain line), and a molding material S. And a control device 4 for controlling the whole.

  The injection device 2 includes a cylinder 5 in which a metering space 5A for the molding material S is formed, a plunger 6 that moves up and down in the metering space 5A, and an extruder 7 attached to a side surface of the cylinder 5 (only the tip in FIG. 1). Show). The injection device 2 includes an injection head 20 fixed to the tip of the cylinder 5 (the lower end in FIG. 1) and a nozzle 30 provided at the tip of the injection head 20, and the nozzle 30 faces the mold 10. Are arranged. The injection device 2 pushes the molding material S from the extruder 7 into the cylinder 5, fills the metering space 5A with a predetermined amount of the molding material S, and moves the plunger 6 into the metering space 5A by a driving device (not shown). Push in. The injection device 2 injects the molding material S in the measurement space 5 </ b> A from the tip (lower end in FIG. 1) of the nozzle 30 through the injection path 21 of the injection head 20 with the pressure of the plunger 6.

  The moving device 3 has a servo mechanism (not shown) attached to the injection device 2, and drives the servo mechanism to bring the injection device 2 closer to and away from the mold 10 (up and down direction in FIG. 1). Move to. The servo mechanism includes, for example, a ball screw mechanism attached to the injection device 2 and a servo motor that drives the ball screw mechanism, and controls the rotation of the servo motor to move the injection device 2 in the moving direction, moving speed, and moving distance. Control (movement amount). The moving device 3 moves the injection device 2 by a servo mechanism to bring the tip of the nozzle 30 into contact with and away from the upper surface of the mold 10. At that time, the moving device 3 controls the amount of movement of the injection device 2 and the nozzle 30 by a servo mechanism, and moves the injection device 2 and the nozzle 30 continuously or by a predetermined distance. Further, the moving device 3 moves the injection device 2 and the nozzle 30 by a predetermined distance unit (in this case, 0.01 mm unit) by a servo mechanism.

  The molding die 10 has a runner member 11, an upper die 12, and a lower die 13 which are combined in a separable manner, and these are arranged in an overlapping manner in the vertical direction. In a state where the upper mold 12 and the lower mold 13 are in contact with each other, a cavity 14 having a predetermined shape is defined on the contact surface side of each other, and a plurality of cavities 14 are formed in the mold 10. In the runner member 11, the injection hole 15 for the molding material S is formed at a position facing the nozzle 30. The runner member 11 defines a passage 16 of the molding material S extending from the injection hole 15 to each cavity 14 together with the upper mold 12. In the molding die 10, the molding material S injected from the injection hole 15 passes through the passage 16 and is filled into the cavity 14, and the molded product P made of the molding material S is molded in the cavity 14.

  In the injection molding machine 1, the injection device 2 is moved by the moving device 3, and the nozzle 30 is brought into contact with the portion (injection port) where the injection hole 15 of the mold 10 is formed. Subsequently, the injection molding machine 1 uses the injection device 2 to inject the molding material S from the nozzle 30 into the injection hole 15 of the molding die 10. Thereby, the injection molding machine 1 injects the molding material S from the nozzle 30 toward the cavity 14 in the molding die 10, and molds the molded product P in the cavity 14. Further, the injection molding machine 1 heats the molding die 10 with a heating device (not shown), heats and vulcanizes the molded product P in the cavity 14, and manufactures the molded product P having a predetermined shape and performance. . Thereafter, the nozzle 30 is separated from the mold 10, the mold 10 is disassembled, and the molded product P is taken out from the cavity 14.

  The injection molding machine 1 continuously manufactures the molded product P by repeatedly assembling and disassembling the molding die 10 and injecting the molding material S. At that time, the injection molding machine 1 injects the molding material S into the molding die 10 from the flow path 31 of the molding material S formed in the nozzle 30 to manufacture a plurality of molded products P simultaneously. In addition, the injection molding machine 1 is provided with a configuration for changing the cross-sectional area of the flow path 31 of the nozzle 30 in the injection head 20, and the flow path 31 has a predetermined cross-sectional area before or during injection of the molding material S. Set to.

FIG. 2 is an enlarged cross-sectional view showing the injection head 20 of the injection molding machine 1 and also shows a part of the molding die 10 against which the nozzle 30 abuts.
The injection molding machine 1 includes a nozzle 30 provided at an injection tip of the molding material S, a base 22 fixed to the cylinder 5, and a nozzle displacement mechanism 40 that displaces the nozzle 30 as shown in the figure. And. In addition, the injection molding machine 1 is provided between the molding die 10 and the throttle part 32 formed in the channel 31 of the nozzle 30, the channel adjusting member 50 that adjusts the channel 31 of the nozzle 30 near the throttle part 32, and the mold 10. Distance measuring means 8 for measuring the distance. The distance measuring unit 8 includes a sensor (for example, a distance sensor or a displacement sensor) that can accurately measure the distance to the measurement target, and is attached to the base 22 toward the upper surface of the mold 10. The distance measuring means 8 measures the distance to the mold 10 and outputs the measurement result (measurement distance) to the control device 4.

  The base 22 has a cylindrical shape, and the injection path 21 of the molding material S is formed in a straight line through the center. A cylindrical recess 23 is formed at the tip of the base 22 around the injection path 21. The injection path 21 is aligned with the measurement space 5A of the cylinder 5 and is continuously arranged at the end of the measurement space 5A, and passes through the molding material S supplied from the measurement space 5A toward the nozzle 30. Let The recess 23 accommodates the fixing member 55 integrated with the flow path adjusting member 50 and a part of the nozzle displacement mechanism 40, and the nozzle displacement mechanism 40 is attached by a female screw portion formed on the inner peripheral surface. ing.

  The nozzle 30 has a cylindrical shape, and the flow path 31 of the molding material S linearly passes through the center and is formed in a circular cross section having a predetermined diameter. Further, the nozzle 30 has an annular protrusion 33 formed on the outer peripheral surface, and is formed to have a different diameter on the opposite side to the mold 10 with the protrusion 33 interposed therebetween. Here, the slide part 35 on the opposite side is formed with a smaller diameter than the tip part 34 on the mold 10 side. The distal end portion 34 is an abutting surface with which the end surface abuts on the mold 10, and the flow path 31 opens on the abutting surface. In the nozzle 30, the flow path 31 is partially throttled at the opening of the flow path 31 to form a throttle portion 32. The throttle portion 32 is a small hole portion having a smaller diameter than other portions of the flow channel 31 and is formed in an annular shape protruding into the flow channel 31 to partially reduce the cross-sectional area of the flow channel 31. In addition, the narrowed portion 32 has a shape (tapered shape) that becomes gradually thinner toward the tip, and a surface facing the flow path adjusting member 50 is formed in an inclined annular shape (tapered shape).

  The nozzle displacement mechanism 40 includes a connecting member 41 connected to the base 22, a holding member 42 that holds the nozzle 30 in a displaceable manner, and a return means 43 that returns the nozzle 30 to a reference position. The connecting member 41 has a cylindrical shape, and a male screw portion formed on the outer periphery of one end is screwed into the female screw portion of the concave portion 23 and fixed to the concave portion 23, and the nozzle displacement mechanism 40 is attached to the base 22. Link. Further, the connecting member 41 has an inner circumference that is larger in diameter than the injection path 21. The holding member 42 has a cylindrical shape, is attached to the outer periphery of the connecting member 41, and is fixed to the connecting member 41 at the flange portion by screws 44. In addition, the holding member 42 has an annular inner peripheral wall 42A formed at the inner periphery of the tip, and a storage portion 45 is defined between the inner peripheral wall 42A and the end surface of the connecting member 41 so that the nozzle 30 protrudes into the storage portion 45. The part 33 is accommodated in a displaceable manner.

  The nozzle 30 is held by the holding member 42 in contact with the inner peripheral wall 42 </ b> A in a state where a gap is opened between the protruding portion 33 and the connecting member 41. When the tip portion 34 is pushed, the nozzle 30 is pushed into the holding member 42 and gradually displaces. When the force pushing the tip portion 34 becomes weak (or disappears), the return means 43 causes the inside of the holding member 42 to move. Is pushed out to return to the position before displacement (reference position). Here, the return means 43 is made of a disc spring, and is disposed between the protruding portion 33 and the connecting member 41, and always exerts a force in a direction of pressing the protruding portion 33 against the inner peripheral wall 42A. The return means 43 is deformed when the nozzle 30 is pushed into the holding member 42, and is restored from the deformation and pushes the nozzle 30 out of the holding member 42 when the pushing force is weakened. That is, the return means 43 is means for applying a force for returning the nozzle 30 to the reference position, and displaces the nozzle 30 according to the force applied to the nozzle 30.

  The nozzle displacement mechanism 40 displaces the nozzle 30 to the inside (inside the injection head 20) when the nozzle 30 is pressed against the molding die 10, and moves the nozzle 30 to the outside according to the release of the pressing of the nozzle 30. Displace. At that time, the nozzle displacement mechanism 40 gradually displaces the nozzle 30 in both directions along the flow direction of the molding material S, and moves the nozzle 30 in and out of the tip portion of the injection head 20. Accordingly, the nozzle 30 is displaced in parallel with the flow direction of the molding material S, with the slide portion 35 and the protruding portion 33 sliding on the inner peripheral surfaces of the connecting member 41 and the holding member 42, respectively. When the nozzle 30 is displaced, the flow path adjusting member 50 is relatively displaced along the flow path 31 in the flow path 31.

  The flow path adjusting member 50 is a member that adjusts the cross-sectional area of the flow path 31 of the nozzle 30, and is disposed in the flow path 31 of the nozzle 30. The flow path adjusting member 50 is made of a rod-shaped member having a predetermined shape (here, a round bar-shaped member), and is disposed at the center of the flow path 31 with a gap between the inner surface of the flow path 31. That is, the flow path adjusting member 50 is inserted into the flow path 31 of the nozzle 30 so that the molding material S can be circulated, and allows the injected molding material S to pass between the outer surface and the inner surface of the flow path 31. Further, the flow path adjusting member 50 extends from the above-described fixing member 55 along the flow path 31 of the nozzle 30, and the distal end surface thereof is disposed close to the throttle portion 32 of the nozzle 30. The front end surface of the flow path adjustment member 50 is an adjustment surface 51 for adjusting the cross-sectional area of the flow path 31, and is formed in a tapered shape that is inclined according to the inclined surface of the throttle portion 32, and faces the throttle portion 32. Arranged.

  When the nozzle 30 is displaced as described above, the flow path adjusting member 50 moves toward and away from the adjustment surface 51, and the gap between the adjustment surface 51 and the edge of the restriction portion 32, and their The cross-sectional area of the flow path 31 in between changes gradually. Further, in the flow path adjustment member 50, when the throttle portion 32 is pressed against the adjustment surface 51, the adjustment surface 51 fits into the hole of the throttle portion 32, and closes the opening of the nozzle 30 to block the flow path 31. As described above, the flow path adjusting member 50 is disposed in the flow path 31 of the nozzle 30, approaches and separates from the throttle portion 32, and the distance (gap) between the throttle portion 32 changes. The flow path adjusting member 50 changes the cross-sectional area of the flow path 31 between the flow path 31 and the throttle section 32 in accordance with the change in the distance to the throttle section 32, and cuts off the flow path 31 from which the molding material S is injected. Adjust the area.

  The flow path adjusting member 50 is formed to have a predetermined diameter (here, a diameter of about 6 to 12 mm) according to the diameter of the flow path 31 so that the molding material S can smoothly pass through the flow path 31 of the nozzle 30. Is done. In the recess 23, the fixing member 55 is fixed with an end flange 56 sandwiched between the base 22 and the connecting member 41. Further, the fixing member 55 includes an injection path 21 continuing from the base 22 and a plurality of branch flow paths 57 from which the injection path 21 branches. The branch flow path 57 extends obliquely from the injection path 21 toward the flow path 31 of the nozzle 30 and allows the molding material S to pass from the injection path 21 to the flow path 31.

  The injection molding machine 1 moves the injection device 2 by the moving device 3 described above, displaces the nozzle 30 by the nozzle displacement mechanism 40, and relatively displaces the flow path adjustment member 50 in the flow path 31. Specifically, the injection molding machine 1 uses the moving device 3 to lower the injection device 2 to bring the nozzle 30 into contact with the mold 10, and further lower the injection device 2 to place the nozzle 30 into the injection head 20. Displace. Thereby, the injection molding machine 1 makes the adjustment surface 51 of the flow path adjustment member 50 and the throttle part 32 approach in the flow path 31, and reduces the cross-sectional area of the flow path 31 between them.

  Further, the injection molding machine 1 raises the injection device 2 by the moving device 3 and displaces the nozzle 30 to the outside of the injection head 20 by the restoring force of a plurality of disc springs as the return means 43. Thereby, the injection molding machine 1 increases the cross-sectional area of the flow path 31 between them by separating the adjustment surface 51 of the flow path adjustment member 50 and the throttle part 32 in the flow path 31. During the injection of the molding material S, the nozzle 30 smoothly moves outside the injection head 20 in contact with the molding die 10 due to the pressure of the molding material S to be injected as the injection device 2 is raised. It is displaced to.

  As described above, the injection molding machine 1 according to the present embodiment changes the distance (gap) between the throttle portion 32 and the flow path adjusting member 50 by the moving device 3 and the nozzle displacement mechanism 40, Change the cross-sectional area. Therefore, the moving device 3 and the nozzle displacement mechanism 40 include distance changing means for changing the distance between the throttle portion 32 and the flow path adjusting member 50, and the flow path between the throttle portion 32 and the flow path adjusting member 50. The cross-sectional area changing means for changing the cross-sectional area of 31 is constituted. The injection molding machine 1 adjusts the distance between the narrowed portion 32 and the flow path adjusting member 50 and the cross-sectional area of the flow path 31 by using this distance changing means (cross-sectional area changing means). Change to area. At this time, the nozzle displacement mechanism 40 included in the distance changing unit displaces the nozzle 30 in contact with the molding die 10 relative to the flow path adjustment member 50, so that the throttle portion 32 approaches the flow path adjustment member 50. , Make them separate. Thereby, the nozzle displacement mechanism 40 changes the relative position of the flow path adjustment member 50 in the flow path 31 to change the distance between the throttle portion 32 and the flow path adjustment member 50 in the flow path 31.

Next, a procedure for molding the molded product P by the injection molding machine 1 and a method for manufacturing the molded product P will be described. The following procedures and operations are controlled and executed by the control device 4 (see FIG. 1) including a computer or the like.
First, the injection molding machine 1 moves the injection device 2 by the moving device 3 to bring the nozzle 30 in which the throttle portion 32 is formed in the flow path 31 into contact with the molding die 10 (see FIG. 2). Further, the nozzle 30 is pressed against the upper surface of the mold 10 with a predetermined force so that the throttle portion 32 and the flow path adjustment member 50 (adjustment surface 51) are brought into contact with each other or arranged at a minimum set distance. In this state, the injection molding machine 1 measures the distance to the mold 10 by the distance measuring unit 8 and stores the measured distance in a memory provided in the control device 4.

  The control device 4 controls the movement of the injection device 2 and the distance changing means described above using the measurement distance stored in the memory as a reference distance. In the present embodiment, the control device 4 calculates the relative displacement amount of the nozzle 30 and the distance between the throttle portion 32 and the flow path adjusting member 50 with the measurement distance as the zero point, and the aperture changing means by the distance changing means. The distance between the part 32 and the flow path adjusting member 50 is changed. Thereby, the control apparatus 4 changes the cross-sectional area of the flow path 31, and controls a cross-sectional area. The injection molding machine 1 measures the distance from the mold 10 by the distance measuring means 8 before each injection of the molding material S, and causes the control device 4 to execute each control described above based on the measured distance. As a result, the injection molding machine 1 prevents a control error from occurring even when expansion or the like occurs due to a change in operation or a temperature change, and accurately controls the cross-sectional area of the flow path 31.

  Subsequently, the injection molding machine 1 manufactures a molded product P by injecting the molding material S into the molding die 10 from the flow path 31 provided in the nozzle 30. In that case, first, in a state where the nozzle 30 is in contact with the mold 10, the distance between the flow path adjusting member 50 disposed in the flow path 31 of the nozzle 30 and the throttle portion 32 is changed to thereby reduce the throttle portion. The cross-sectional area of the flow path 31 between 32 and the flow path adjustment member 50 is adjusted. The injection molding machine 1 accurately adjusts the cross-sectional area based on the measurement distance of the distance measuring unit 8 and adjusts the cross-sectional area of the flow path 31 to a preset cross-sectional area. Here, the gap between the adjustment surface 51 of the flow path adjustment member 50 and the throttle portion 32 is mainly smaller than the gap between the inner surface of the flow path 31 and the outer surface of the flow path adjustment member 50. In addition, the cross-sectional area of the flow path 31 is set. Next, the injection molding machine 1 injects the molding material S into the molding die 10 through the flow path 31 between the throttle portion of the nozzle 30 and the flow path adjusting member 50, and molds the molded product P in the cavity 14. To do. In addition, the injection molding machine 1 manufactures the molded product P by vulcanizing the molded product P in the molding die 10.

  As described above, the injection molding machine 1 changes the cross-sectional area of the flow path 31 between them by changing the distance between the throttle portion 32 and the flow path adjusting member 50 in the flow path 31 of the nozzle 30. . Therefore, the labor and time required for changing the cross-sectional area of the flow path 31 can be reduced, the cross-sectional area of the flow path 31 can be easily changed, and the cross-sectional area of the flow path 31 can be adjusted easily and accurately. Along with this, the cross-sectional area of the flow path 31 can be changed at any time, so that the flow path 31 of the nozzle 30 can always have an optimal cross-sectional area. In addition, since the cross-sectional area of the flow path 31 can be set as appropriate in accordance with changes in the type of molding material S and molded product P, the season, and the temperature without replacing the nozzle 30, it is necessary to replace the nozzle 30. And save time. Furthermore, by adjusting the cross-sectional area of the flow path 31, the injection condition of the molding material S can be easily and accurately changed to a condition corresponding to the situation at the time of injection. As a result, since the molding material S can be appropriately heated at the time of injection from the flow path 31, it is possible to control the temperature of the molding material S with high accuracy and to suppress fluctuations in the temperature of the molding material S to be injected.

  Therefore, according to the present embodiment, the cross-sectional area of the flow path 31 of the nozzle 30 can be easily changed, and the temperature of the molding material S injected from the flow path 31 of the nozzle 30 into the molding die 10 can be accurately controlled. it can. Moreover, since the temperature difference with respect to the target temperature of the molding material S can be reduced at the time of injection, the quality of the molded product P can also be stabilized. As a result, even when the molded product P made of rubber is produced, it is possible to prevent over-vulcanization or insufficient vulcanization, thereby reducing variations in vulcanization. At the same time, since the molded product P can be heated to an appropriate temperature in advance, the vulcanization time can be shortened (for example, conventional 1/4 to 1/2). Thus, since the time required for manufacturing the molded product P can be shortened, the productivity of the molded product P can also be improved.

  In this injection molding machine 1, since the throttle part 32 is formed in the flow path 31 of the nozzle 30, the molding material S heated by the throttle part 32 can be injected from the flow path 31 while suppressing temperature fluctuations. In addition, the molding material S is less likely to be burned (rubber burnt) or clogged in the flow path 31, and the molding material S can be reliably injected from the flow path 31 within a predetermined time. Further, even when the molding material S is burned or clogged in the flow path 31, the screw 44 is removed, the holding member 42 and the nozzle 30 are disassembled, and the flow path 31 of the nozzle 30 and the flow path adjustment member 50 are cleaned. do it. As described above, the nozzle 30 can be easily disassembled and the flow path 31 and the like can be cleaned without disassembling the entire injection device 2 and the injection head 20, so that burning and clogging of the molding material S can be easily eliminated.

  Here, when the flow path 31 of the nozzle 30 has a simple circular cross-section, the temperature of the molding material S passing through the flow path 31 is higher on the outer side in contact with the inner surface of the flow path 31 and lower at the center. On the other hand, in this embodiment, since the flow path adjusting member 50 is composed of a rod-shaped member inserted into the flow path 31 of the nozzle 30, the cross-sectional shape of the flow path 31 is a ring shape, and the surface on which the molding material S contacts Will increase. Therefore, the molding material S is heated from the inside and outside while passing through the flow path 31, and the temperature rises also on the inside, and the temperature difference between the inside and outside is reduced and the overall temperature becomes more uniform. At this time, if the flow path adjustment member 50 is a round bar-like member, the molding material S around the flow path adjustment member 50 is heated uniformly, and the temperature of the molding material S becomes more uniform. Therefore, it is more preferable that the flow path adjusting member 50 is composed of a round bar member.

  When the molded product P is manufactured, the molding material S may be injected from the nozzle 30 into the molding die 10 without changing the cross-sectional area of the flow path 31. Further, the cross-sectional area of the flow path 31 may be changed while the molding material S is being injected into the mold 10. When changing the cross-sectional area, the distance change means is controlled by the control device 4 which is a control means, and the distance between the throttle portion 32 and the flow path adjusting member 50 is set within one cycle from the start to the end of injection. Change. Thereby, the cross-sectional area of the flow path 31 is changed in a predetermined pattern. In this way, since the temperature of the molding material S can be controlled even during injection, the temperature of the molding material S can be adjusted to a temperature corresponding to each stage of injection. Alternatively, even when the temperature of the molding material S changes during one injection, the temperature of the molding material S can be controlled by adjusting the temperature of the molding material S, so that the temperature of the molding material S can be maintained within a certain range.

  The temperature of the molding material S is low at the start of injection, and gradually increases at the initial stage of injection, then decreases at the middle stage of injection, and gradually decreases at the final stage of injection. Therefore, for example, the cross-sectional area of the flow path 31 is reduced at the start of injection in response to the temperature change of the molding material S, gradually increased at the initial stage of injection, and then kept constant at the middle stage of injection. In the final stage of injection, gradually reduce it. As a result, the temperature of the molding material S increases at the initial stage and the final stage of injection, and decreases at the middle stage of injection. As a result, the molding material S has a small temperature change during one injection and is injected at a temperature within a certain range. Further, when the injection of the molding material S is completed, if the cross-sectional area of the flow path 31 is slightly widened, the molding material S to be injected last is unlikely to be burned, and the clogging of the nozzle 30 is prevented.

Next, another embodiment of the injection molding machine 1 will be described. Here, the injection molding machine 1 includes an injection head 20 </ b> A that is partially different from the above-described injection head 20.
FIG. 3 is a cross-sectional view showing an ejection head 20A according to another embodiment.
The injection head 20A includes an injection path 21, a base 22, a nozzle displacement mechanism 40, a nozzle 60, and a flow path adjustment member 70 as illustrated. The injection head 20 </ b> A is configured in the same manner as the above-described injection head 20 except for the nozzle 60 and the flow path adjusting member 70. Therefore, in the following description, the nozzle 60 and the flow path adjusting member 70 will be described, and description of other components assigned the same numbers as those of the injection head 20 (see FIG. 2) will be omitted. The nozzle 60 and the flow path adjusting member 70 are basically configured similarly to the nozzle 30 and the flow path adjusting member 50 described above.

  Similarly to the nozzle 30, the nozzle 60 includes a flow path 61, a throttle part 62 formed in the flow path 61, a protruding part 63 on the outer peripheral surface, a tip part 64, and a slide part 65. However, in this nozzle 60, the flow path 61 is partially throttled at a midway position away from the opening of the flow path 61 to form a throttle portion 62. Further, the diaphragm portion 62 is formed in a tapered shape in which both surfaces sandwiching the tip end are inclined in the opposite direction.

  The flow path adjusting member 70 is a rod-shaped member disposed in the flow path 61 of the nozzle 60, and an integrally formed fixing member 75 is fixed to the concave portion 23 of the base 22. The fixing member 75 is configured in the same manner as the above-described fixing member 55, and includes a flange 76 and a branch channel 77. Further, the flow path adjusting member 70 has a constricted portion 72 having a smaller diameter than other portions and a distal end portion 73 following the constricted portion 72 in the vicinity of the throttle portion 62 of the nozzle 60. The constricted portion 72 is formed to have a smaller diameter than the throttle portion 62, and is disposed through the throttle portion 62 with a gap between the narrow portion 72 and the throttle portion 62. The distal end portion 73 has a disk shape larger in diameter than the constricted portion 72 and the throttle portion 62, and is disposed between the opening portion of the flow channel 61 and the throttle portion 62 in the flow channel 61 of the nozzle 60. Further, the tip 73 has an adjustment surface 71 that adjusts the cross-sectional area of the flow path 61 at the surface facing the throttle portion 62. The adjustment surface 71 is formed in a tapered shape that is inclined in accordance with the inclined surface of the diaphragm portion 62, and is disposed to face the lower surface of the diaphragm portion 62.

  In the flow path adjusting member 70, the adjustment surface 71 comes into contact with the throttle portion 62 of the nozzle 60, and the throttle surface 62 is blocked by the adjustment surface 71 to block the flow channel 61. From this state, when the nozzle 60 is pressed against the molding die 10 and the nozzle 60 is displaced into the injection head 20, the throttle portion 62 moves away from the adjustment surface 71, and the gap between them and the cross-sectional area of the flow path 61 are increased. growing. Further, when the nozzle 60 is displaced outside the ejection head 20, the throttle portion 62 approaches the adjustment surface 71, and the cross-sectional area of the flow path 61 between them becomes small. That is, in the injection head 20A, contrary to the above-described injection head 20, when the injection device 2 descends, the cross-sectional area of the flow path 61 increases, and when the injection apparatus 2 rises, the cross-sectional area of the flow path 61 decreases. Become.

  The injection molding machine 1 changes the cross-sectional area of the flow path 61 according to the displacement of the nozzle 60 by changing the distance between the throttle portion 62 and the flow path adjusting member 70 by the distance changing means. Thereby, the injection molding machine 1 adjusts the cross-sectional area of the flow path 61 in the throttle part 62 in the flow path 61, and then passes through the flow path 61 between the throttle part 62 and the flow path adjustment member 70. Is injected into the mold 10. Therefore, each of the above-described effects can be obtained with this ejection head 20A. In addition, here, the flow path 61 is blocked by the flow path adjusting member 70 before the nozzle 60 contacts the mold 10 and after the nozzle 60 is separated from the mold 10. Therefore, it is possible to prevent the molding material S from leaking from the nozzle 60 while the molding material S is filled in the measuring space 5A or before and after the molding material S is injected.

  The return means 43 of the nozzle displacement mechanism 40 may control the displacement of the nozzles 30 and 60 by providing, for example, a mechanism for displacing the nozzles 30 and 60 with hydraulic pressure in a space that accommodates the disc spring. . Alternatively, the return means 43 may return the nozzles 30 and 60 using an elastic member such as a coil spring in addition to the disc spring. Further, when the throttle portions 32 and 62 of the nozzles 30 and 60 and the flow path adjusting members 50 and 70 are brought closest, they may be in contact with each other, and a gap of a predetermined distance may be formed between them. .

  The injection molding machine 1 described above is suitable for a rubber injection molding machine that injects a rubber having a relatively long injection time as the molding material S. However, the injection molding machine for resin molding a resin molded product by injecting a resin. It can also be applied to machines. The injection molding machine 1 can also manufacture a molded product P made of only the molding material S. By inserting a part into the cavity 14 in advance, the injection molding machine 1 can manufacture the molded product P made of the molding material S and the part. You can also.

  DESCRIPTION OF SYMBOLS 1 ... Injection molding machine, 2 ... Injection apparatus, 3 ... Moving apparatus, 4 ... Control apparatus, 5 ... Cylinder, 5A ... Measuring space, 6 ... Plunger, 7 * .... Extruder, 8 ... Distance measuring means, 10 ... Mold, 11 ... Runner member, 12 ... Upper mold, 13 ... Lower mold, 14 ... Cavity, 15 ... -Injection hole, 16 ... passage, 20, 20A ... injection head, 21 ... injection path, 22 ... base, 23 ... recess, 30 ... nozzle, 31 ... flow path , 32 ... throttle part, 33 ... projecting part, 34 ... tip part, 35 ... slide part, 40 ... nozzle displacement mechanism, 41 ... connecting member, 42 ... holding member 42A ... inner peripheral wall, 43 ... return means, 44 ... screw, 45 ... housing part, 50 ... flow path adjusting member, 51 ... Nodal surface, 55 ... fixing member, 56 ... flange, 57 ... branch channel, 60 ... nozzle, 61 ... channel, 62 ... throttle part, 63 ... projection part 64 ... tip part, 65 ... slide part, 70 ... flow path adjustment member, 71 ... adjustment surface, 72 ... constricted part, 73 ... tip part, 75 ... fixed Member, 76 ... flange, 77 ... branch channel, P ... molded product, S ... molding material.

Claims (6)

An injection molding machine comprising a nozzle having a flow passage for a molding material, and injecting the molding material into the mold from the flow passage of the nozzle,
A throttle formed in the flow path of the nozzle;
A flow path adjusting member that is arranged in the flow path of the nozzle and changes a cross-sectional area of the flow path with the throttle portion in accordance with a change in the distance to the throttle portion;
Distance changing means for changing the distance between the throttle portion and the flow path adjusting member;
Injection molding machine equipped with. In the injection molding machine according to claim 1,
An injection molding machine having a nozzle displacement mechanism in which the distance changing means displaces the nozzle with respect to the flow path adjusting member to change the distance between the throttle portion and the flow path adjusting member. In the injection molding machine according to claim 1 or 2,
An injection molding machine comprising control means for controlling a distance changing means to change a cross-sectional area of a flow path during injection of a molding material into a mold. In the injection molding machine according to any one of claims 1 to 3,
An injection molding machine in which the flow path adjusting member is a rod-shaped member inserted into the flow path of the nozzle. A method for manufacturing a molded product, in which a molding material is manufactured by injecting a molding material from a flow path provided in a nozzle into a mold,
A step of bringing a nozzle having a throttle portion formed in the flow path into contact with a mold;
Changing the distance between the flow path adjustment member disposed in the flow path of the nozzle and the throttle part, and adjusting the cross-sectional area of the flow path between the throttle part and the flow path adjustment member;
Injecting a molding material into a molding die through a flow path between a nozzle narrowing portion and a flow path adjusting member;
The manufacturing method of the molded article which has this. In the manufacturing method of the molded article according to claim 5,
A method for producing a molded product, comprising a step of changing a cross-sectional area of a flow path by changing a distance between a throttle portion and a flow path adjusting member during injection of the molding material into a mold.

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