Fixed platen and injection molding apparatus equipped with this fixed platen

Abstract

The objective is to provide a fixed platen that can simultaneously advance and retract multiple valve pins of a mold without providing drive motors or drive structures for each mold, and an injection molding apparatus equipped with this fixed platen. [Solution] The fitting plates 21b of a pair of valve pin movable member mounting members 2 fixed to the fixed platen body 1 of the fixed platen A are fitted into the fitting recess 41a of the fixed side mounting plate 41 of the fixed mold 4a, and the engaging pin 22f of the valve pin movable member driving mechanism 2 is engaged with the engaging recess 42a of the valve pin movable member 42 of the fixed mold 4, and the piston rods 32 of the pair of electric cylinders 3 are moved forward and backward to move the valve pin movable member 42 toward the fixed mold body 43.

Description

Technical Field

[0001] The present invention relates to a fixed platen (also referred to as a fixed plate) and an injection molding apparatus including the fixed platen.

Background Art

[0002] In an injection molding apparatus, a conventional injection mold in which a fixed mold includes a plurality of gates and a plurality of resin flow path portions provided in parallel and each connected to each gate has a valve pin provided for each gate advancing and retreating in a direction to open and close the gate by a driving motor provided for each of them (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of a conventional injection mold, as described above, the number of driving motors is required as many as the number of gates, and since it is necessary to synchronize each driving motor, there is a problem that the control becomes complicated and the cost becomes high. In addition, since the driving motors are bulky, there is a limit to the pitch between the valve pins, and if the number of gates is increased, the entire mold must be enlarged. As a result, there is a problem that the entire injection molding apparatus must be enlarged. However, in the case of the above injection mold, it is necessary to provide a driving motor for each mold and a driving structure for advancing and retreating the plate assembly, and there is a problem that the mold cost increases.

[0005] In view of the above circumstances, the present invention aims to provide a fixed platen that can simultaneously advance and retract a number of valve pins in a mold without providing a drive motor or drive structure in the mold, and an injection molding apparatus equipped with this fixed platen. [Means for solving the problem]

[0006] The present invention relates to a fixed platen used in an injection molding apparatus that includes a fixed mold having a fixed mold body having a plurality of gates and a plurality of parallel resin flow channels connected to each gate, a valve pin movable member having a plurality of valve pins that move back and forth within each resin flow channel to open and close the gates simultaneously, and a fixed side mounting plate. The fixed platen is characterized in that it includes a fixed platen body that is detachably attached to the fixed side mounting plate, and a valve pin movable member drive mechanism that is detachably attached to the valve pin movable member and, when attached, moves the valve pin movable member back and forth, wherein the valve pin movable member drive mechanism has a drive mechanism body and a drive unit driven by the drive mechanism body, the drive mechanism body and the drive unit are arranged on one side and the other side of the valve pin movable member, respectively, the drive unit has a mounting portion that is detachably attached to the valve pin movable member, and when the mounting portion is attached to the valve pin movable member, it is provided to move back and forth in the direction of the valve pin movable member together with the valve pin movable member by the driving force of the drive mechanism body.

[0007] In the fixed platen of the present invention, the drive mechanism body is not particularly limited, but examples include an electric cylinder, a hydraulic cylinder, an air cylinder, and a rack and pinion mechanism. Among these, an electric cylinder is preferred because it offers high-precision positioning, flexible motion control, energy saving, and ease of maintenance.

[0008] In the fixed platen of the present invention, the drive unit is not particularly limited, but it can be configured to have a drive arm having a mounting portion at one end and moving back and forth in the direction of advancement and retraction of the valve pin movable member by the driving force of the drive mechanism body.

[0009] In the fixed platen of the present invention, the mounting portion may be an engagement pin, and the valve pin movable member may be configured to have an engagement recess on its side surface that allows the engagement pin to be attached by engagement.

[0010] The injection molding apparatus of the present invention is characterized by comprising the fixed platen of the present invention described above. [Effects of the Invention]

[0011] The present invention provides a fixed platen used in an injection molding apparatus that includes a fixed mold having a fixed mold body having a plurality of gates and a plurality of parallel resin flow channels connected to each gate, a valve pin movable member having a plurality of valve pins that move back and forth within each resin flow channel to open and close the gates simultaneously, and a fixed side mounting plate, wherein the fixed platen body is detachably attached to the fixed side mounting plate, and the fixed platen includes a valve pin movable member drive mechanism that is detachably attached to the valve pin movable member and moves the valve pin movable member back and forth when attached, wherein the valve pin movable member drive mechanism includes a drive mechanism body and a drive unit driven by the drive mechanism body, and the drive mechanism body and drive The parts are arranged on one side and the other side of the valve pin movable member, respectively, and the drive unit has a mounting part that can be attached to the valve pin movable member, and when this mounting part is attached to the valve pin movable member, it is provided to move back and forth in the direction of advancement and retraction of the valve pin movable member together with the valve pin movable member by the driving force of the drive mechanism body, so that a fixed type fixed-side mounting plate is attached to the fixed platen body and the valve pin movable member mounting part is attached to the valve pin movable member, the valve pin movable member can be moved toward and away from the fixed platen body and the fixed-side mounting plate attached to the fixed platen body by the driving force of the pair of drive mechanism bodies provided on the fixed platen.

[0012] In other words, by using this fixed platen, multiple valve pins can be moved forward and backward at once without having to install a drive motor for each mold, thus reducing mold costs.

[0013] Since the injection molding apparatus of the present invention is equipped with the fixed platen of the present invention described above, it is not necessary to provide a drive mechanism for the valve pin movable member in the mold itself. In other words, by simply attaching a desired hot runner mold, in which a number of gates are provided at desired positions, to the fixed platen of the present invention, a number of gate valve pins can be moved forward and backward simultaneously. Therefore, there is no need to provide a drive mechanism for the movable valve pin member for each mold, and mold costs can be reduced. Furthermore, since the only change is to use the fixed platen of the present invention in place of the conventional fixed platen, there is no need to modify other parts of the injection molding apparatus. In other words, the conventional injection molding apparatus can be used as is. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view showing one embodiment of the fixed platen of the present invention. [Figure 2] Figure 1 is a front view of the fixed platen. [Figure 3] Figure 1 is a perspective view of the valve pin movable member drive mechanism of the fixed platen. [Figure 4] Figure 1 is a perspective view showing the mold attached to the fixed platen. [Figure 5] Figure 4 is a front view. [Figure 6] This is a cross-sectional view along line XX in Figure 5. [Figure 7] This is a cross-sectional view along the YY line in Figure 6. [Figure 8] Figure 1 is a front view of an injection molding apparatus with a fixed platen installed. [Figure 9] This is a plan view of the injection molding apparatus with the fixed platen shown in Figure 1. [Figure 10] Figure 3 illustrates the movement of the valve pin movable member drive mechanism, where Figure (a) is a side view of the state in which the engagement pin has been moved toward the fixed platen body, and Figure (b) is a cross-sectional view of Figure (a). [Figure 11]It is a diagram for explaining the movement of the valve pin movable member drive mechanism section in FIG. 3, where (a) in the figure is a side view of the state where the engagement pin is moved to the fixed side, and (b) in the figure is a cross-sectional view of (a) in the figure. [Figure 12] It is a perspective view of an electric cylinder mounted on the fixed platen of FIG. 1.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the present invention will be described in detail while referring to the drawings showing its embodiments. FIGS. 1 to 2 show one embodiment of the fixed platen of the present invention.

[0016] As shown in FIGS. 1 to 2, this fixed platen A includes a fixed platen main body 1 and a pair of valve pin movable member drive mechanism sections 2. The fixed platen main body 1 includes a sprue bush 11 into which the injection nozzle of an injection machine is fitted.

[0017] The pair of valve pin movable member drive mechanism sections 2 are provided on the mold fixed side surface of the fixed platen main body 1 so as to oppose each other across the central axis of the sprue bush 11. As shown in FIGS. 1 to 3, they include an electric cylinder 3 as the drive mechanism section main body, a base section 21, and a drive section 22. The base section 21 includes a base section main body 21a and a pair of fitting plates 21b.

[0018] The base section main body 21a is screwed to the fixed platen main body 1. The pair of fitting plates 21b are symmetrically provided on both sides in the longitudinal direction of the base section main body 21a, and are screwed to the base section main body 21a in a state of being fitted into fitting recesses 41a provided on the side surface of a fixed side mounting plate 41 of an injection mold 4 to be described later, so as to fix the fixed side mounting plate 41 to the fixed platen main body 1.

[0019] As shown in Figures 1 to 5, the drive unit 22 comprises a cylinder portion 22a, a piston 22b, a drive transmission bar 22c, an arm portion 22e, and a pair of link plates 22d. The cylinder portion 22a is supported and fixed to the base portion 21 and is equipped with a linear bush 221, as shown in Figure 4(b).

[0020] As shown in Figure 4(b), the piston 22b is slidably fitted into the linear bush 221 of the cylinder portion 22a and can extend and retract from one end of the cylinder portion 22a. The drive transmission bar 22c is fixed to the tip of the piston 22b via a screw 225 so as to be parallel to the side wall surface of the valve pin movable member 42, which will be described later.

[0021] The arm portion 22e is roughly U-shaped, with the open ends of both lateral pieces of the U-shape protruding from the cylinder portion 22a toward the other valve pin movable member drive mechanism portion 2, and both lateral pieces are pivotally supported to the cylinder portion 22a via pivot bolts 224. Furthermore, at the open ends of the U-shaped lateral sections of the arm section 22e, engagement pins 22f are supported and fixed so as to be perpendicular to the lateral sections of the U-shape. These engagement pins serve as mounting parts that engage with the engagement recesses 42a of the valve pin movable member 42 of the injection mold 4, which will be described later.

[0022] Of the pair of link plates 22d, one link plate 22d is pivotally supported at one end to one end of the drive transmission bar 22c via a pivot bolt 222, and the other end is pivotally supported at one side of the U-shaped arm portion 22e via a pivot bolt 223. Of the pair of link plates 22d, one end of the other link plate 22d is pivotally supported to the other end of the drive transmission bar 22c via a pivot bolt 222, and the other end is pivotally supported to the other horizontal piece of the U-shape of the arm portion 22e via a pivot bolt 223.

[0023] In other words, as shown in Figure 4, when the piston 22b moves to protrude from the cylinder portion 22a, the arm portion 22e rotates via the pair of link plates 22d so that the engagement pin 22f moves closer to the base portion 21 on the pivot bolt 224. On the other hand, as shown in Figure 5, when the piston 22b moves in the direction of retracting into the cylinder portion 22a, the arm portion 22e rotates around the pivot bolt 224 via the pair of link plates 22d so as to move the engagement pin 22f away from the base portion 21.

[0024] Each of the pair of electric cylinders 3 comprises a cylinder body 31 and a piston rod 32, as shown in Figure 6. Although not shown in the figure, the cylinder body 31 is designed to convert the rotational force applied by a motor with an encoder into linear motion using a ball screw or the like, thereby allowing the piston rod 32 to move back and forth in the axial direction. The tip of the piston rod 32, although not shown in the figure, is connected to the piston 22b within the cylinder portion 22a, and its movement causes the piston 22b to extend and retract from the cylinder portion 22a.

[0025] As described above, this fixed platen A is attached to the injection molding apparatus B as shown in Figures 11 and 12, and the fixed mold 4a of the injection mold 4 is supported on the fixed platen A as shown in Figures 7 to 9. In other words, the fixed type 4a comprises a fixed-side mounting plate 41, a valve pin movable member 42, and a fixed-type body 43.

[0026] As shown in Figures 7 and 9, the fixed mounting plate 41 has a fitting recess 41a on its side surface, facing the fitting plate 21b of the valve pin movable member drive mechanism 2. The plate is fixed to the fixed platen body 1 by fixing a portion of the fitting plate 21b to the base body 21a while fitted into the fitting recess 41a. As shown in Figures 9 and 10, the valve pin movable member 42 has an engagement recess 42a on its side surface at a position facing the engagement pin 22f of the valve pin movable member drive mechanism 2, and as shown in Figure 10, a number of valve pins 42b are provided in parallel at a position facing the resin flow channel (not shown) of the fixed body 43.

[0027] The valve pin movable member 42 moves back and forth in the direction of the fixed body 43 when the piston rods 32 of the pair of electric cylinders 3 move back and forth synchronously, with the engaging pin 22f engaged with the engaging recess 42a. In other words, when the engaging pin 22f rotates toward the fixed body 43, the valve pin movable member 42 moves toward the fixed body 43, and the valve pin 42b closes the gate (not shown). When the engaging pin 22f rotates toward the fixed body 43, the valve pin movable member 42 moves toward the fixed mounting plate 41, and the gate is opened. The movable type 4b is fixed to a movable platen (not shown), and when the movable platen moves toward the fixed platen A, it closes with the fixed type 4a, and when the movable platen retracts from the fixed platen A, the closure with the fixed type 4a is released.

[0028] As described above, this injection molding apparatus B is equipped with the fixed platen A of the present invention, and can perform molding as follows. (1) The fitting plate 21b of the valve pin movable member drive mechanism 2 is fitted into the fitting recess 41a of the fixed mounting plate 41 to fix the fixed mold 4a of the injection mold 4 to the fixed platen A. (2) Fix the movable type 4b to the movable platen. Note that the order of (1) and (2) does not matter. (3) Insert the nozzle of the injection machine into the sprue bush 11 of the fixed platen A. (4) Move the movable platen toward the fixed platen A to close the fixed mold 4a and the movable mold 4b. (5) The electric cylinder 3 is operated to move the piston 22b in a direction that protrudes from the cylinder portion 22a, as shown in Figure 4, and the engaging pin 22f is rotated toward the fixed platen body 1, thereby sliding the valve pin movable member 42 toward the fixed platen body 1 and moving each valve pin 42b to the position that opens the gate. (6) After each valve pin 42b moves to the position that opens the gate, molten resin is injected from the injection machine into the cavity (not shown) of the injection mold 4. (7) After filling is complete, the electric cylinder 3 is operated to move the piston 22b in the direction of retraction into the cylinder part 22a, as shown in Figure 5, and the engaging pin 22f is rotated toward the fixed body 43, thereby sliding the valve pin movable member 42 toward the fixed body 43 and moving each valve pin 42b to the position that closes the gate. (8) After cooling is complete, the movable platen is moved to move the movable mold 4b to the mold open position, and then the molded product is removed. Then, steps (4) to (8) are repeated to continuously mold the product.

[0029] As described above, the injection molding apparatus B is equipped with the fixed platen A of the present invention. Therefore, if the fixed mold 4a is an injection mold 4 equipped with a valve pin movable member 42, all valve pins 42b can be moved forward and backward by the two electric cylinders 3 without providing a drive mechanism to the injection mold 4 which is equipped with a large number of valve pins.

[0030] Furthermore, even if the gate position or cavity structure is different, if the injection mold 4 is equipped with the valve pin movable member 42 described above, the fixed mold 4a can be attached to the fixed platen A in the same manner as described above, and molding can be performed in the same way. In other words, as described above, the injection molding apparatus B equipped with this fixed platen A can open and close all gates by moving the numerous valve pins of all injection molds forward and backward using the two electric cylinders 3, as long as the injection molds can be attached to the fixed platen A in the manner described above.

[0031] The present invention is not limited to the embodiments described above. For example, in the above embodiments, the fitted state in the fitted recess was maintained by screw fixing the fitted plate to the base body, but the fitted plate may be supported by the base body so as to be slidable in the direction of the fitted recess, and biased to fit into the fitted recess by a biasing means such as a spring provided on the base body. [Explanation of Symbols]

[0032] A Fixed platen B Injection molding equipment 1 Fixed platen body 11 Spruce Bush 2. Valve pin movable member drive mechanism 21 Base section 21a Base unit 21b Mating plate 22 Drive unit 22a Cylinder section 22b Piston 22c drive transmission bar 22d Link Plate 22e Arm section 22f Engagement pin (mounting part) 221 Linear Bushing 222 pivot bolts 223 Pivot bolts 224 pivot bolts 225 pivot bolt 3. Electric Cylinder (Drive Mechanism Body) 31 Cylinder body 32 Piston Rods 4. Injection mold 4a fixed type 4b Movable type 41 Fixed mounting plate 41a Fitting recess 42 Valve pin movable member 42a Engagement recess 43 Fixed body

Claims

1. A fixed body having multiple gates and multiple parallel resin flow channels connected to each gate, A valve pin movable member having multiple valve pins that can move back and forth simultaneously within each resin flow path to open and close the gate, Used in an injection molding apparatus equipped with a fixed mold having a fixed mounting plate, the fixed platen body is detachably attached to the fixed mounting plate, A fixed platen comprising a valve pin movable member drive mechanism that is detachably attached to the valve pin movable member and moves the valve pin movable member forward and backward when attached, The valve pin movable member drive mechanism comprises a drive mechanism body and a drive unit driven by the drive mechanism body, and is arranged on one side and the other side of the valve pin movable member, The fixed platen is characterized in that the drive unit has a mounting portion that can be detachably attached to the valve pin movable member, and when the mounting portion is attached to the valve pin movable member, it is provided to move back and forth in the direction of advancement and retraction of the valve pin movable member together with the valve pin movable member by the driving force of the drive mechanism body.

2. The fixed platen according to claim 1, wherein the drive mechanism body is an electric cylinder having a piston rod that slides in the direction of advancement and retraction of the valve pin movable member to advance and retract the mounting portion.

3. The fixed platen according to claim 1, wherein the drive unit has the mounting portion at one end and is equipped with a drive arm that moves the valve pin movable member in the direction of advancement and retraction by the driving force of the drive mechanism body.

4. The fixed platen according to claim 1, wherein the mounting portion is an engagement pin, and the valve pin movable member has an engagement recess on its side surface that allows the engagement pin to be attached by engagement.

5. An injection molding apparatus characterized by comprising a fixed platen as described in claim 1.

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