JP5435196B2 - Flow control valve, injection molding machine and injection molding method in multi-point gate injection molding - Google Patents

Description

  The present invention relates to a flow control valve, an injection molding machine, and an injection molding method in multi-point gate injection molding, and more specifically, is used for multi-point gate injection molding for molding a multi-piece or a single-piece molded product having a large projected area. The present invention relates to a flow control valve, an injection molding machine having the flow control valve, and an injection molding method.

  In injection molding of resin moldings, multi-point gate molds are used for single molding of resin moldings with a large projected area and so-called family mold molding for simultaneously molding molded products with different filling amounts and weight ratios. In the case of the multi-point gate type, the amount of filling from each nozzle is adjusted to control the movement of the weld line formation part of the molded product to a desired position, or filling from many nozzles. It is necessary to adjust so that large and small molded products can be set stably.

  In order to adjust and control the filling amount in a large number of nozzles, for example, as described in Patent Documents 1 and 2, the filling amount by each nozzle is adjusted by changing the amount of resin injected from each nozzle gate. It is done by doing.

  In both of the techniques of Patent Documents 1 and 2, the needles from the side of the runner portion are formed on the runner portion of the manifold that branches the resin into the cavity of the multipoint gate injection mold at an angle substantially perpendicular to the resin flow direction. The pin is disposed so as to be able to advance and retreat with respect to the runner portion, and the flow rate of resin passing through the runner portion is controlled by adjusting the amount of the needle pin entering the runner portion.

  However, in injection molding, a great amount of pressure is applied to the molten resin passing through the runner portion, which is a resin flow path, so that a large pressure is also applied to the damming pin that has entered the runner portion. In particular, when the damming pin is made to enter the most part and the runner is blocked to completely stop the molten resin from passing, a great amount of pressure is applied to the damming pin. Has been found to occur, and in some cases can be damaged or even broken.

Publicity Sho Sho 62-166017 JP 2004-050425 A

  In the course of continuing research on the nozzle gate opening / closing timing adjustment mechanism in general, the inventor has provided the damming pin on the contact surface of the runner, which is the portion where the tip of the damming pin comes into contact when the damming pin is most advanced. It was found that the above-described damming pin can be prevented from being distorted and damaged or broken by forming a recess that supports the tip by entering the tip.

  However, further research on this configuration has made it possible to prevent problems such as distortion at the time of the most recent entry of the weir pin (when the resin flow is cut off), but at the time of the most approach (when the resin flow is cut off) In other cases, molten resin stays in the recesses formed on the contact surface of the runner, or turbulence occurs when the flow of the molten resin passes through the recesses. It was found that failures such as "weld lines" are likely to occur, and further research was necessary.

  Therefore, the problem of the present invention is that even when the damming pin is moved into the runner part and the resin flow path is shut off, the damming pin is not distorted, damaged or broken, and the molten resin flow is not retained. An object of the present invention is to provide a flow control valve, an injection molding machine, and an injection molding method in multi-point gate injection molding that can suppress the occurrence of turbulent flow.

  The present invention for solving the above problems has the following configuration.

1. Each runner part except the corner part of the manifold that branches the resin into the cavity of the multi-point gate injection mold has a damming pin from the side of each runner part at an angle substantially perpendicular to the resin flow direction. It is arranged so as to be able to advance and retreat with respect to the inside of the runner part, and the resin passes through each runner part by adjusting the amount of the plurality of damming pins entering each runner part leading to each gate of the multipoint gate. A flow control valve for controlling each possible flow rate,
The weir pin has a hemispherical convex curved surface at its tip,
In each runner portion, a hemispherical concave curved surface is formed that receives the convex curved surface of the tip of the damming pin on the runner contact surface, which is the portion where the tip of the damming pin abuts when the damming pin is most advanced. The flow rate control valve in multi-point gate injection molding, characterized by having a configuration.

2. 2. The flow control valve in multipoint gate injection molding according to 1 above, wherein the damming pin is configured to continuously adjust the amount of entry into the runner portion by screwing operation and loosening operation.

3. 3. The flow control valve in the multipoint gate injection molding as described in 1 or 2 above, wherein the runner portion is cut off when the damming pin is most advanced.

4). An injection molding machine comprising a flow rate control valve in the multipoint gate injection molding described in any one of 1 to 3 above.

5. 5. The injection molding machine as described in 4 above, wherein the injection molding is performed by a hot runner system or an open gate system.

6). An injection molding method performed using the flow rate control valve in the multipoint gate injection molding according to any one of the above 1 to 3,
Performing screwing operation or loosening operation of the damming pin, each modulate a plurality of ingress of the blocking pin into the runner portion communicating with a plurality of the gates of the multi-point gate, the resin can pass in each runner An injection molding method characterized by controlling each flow rate.

  According to the invention shown in claim 1, 4 or 6, even when the damming pin is most advanced into the runner portion and the resin flow path is shut off, the damming pin is not distorted, damaged or broken, In addition, it is possible to provide a flow control valve, an injection molding machine, and an injection molding method in multi-point gate injection molding that can suppress the stay of molten resin flow and the occurrence of turbulent flow.

  In particular, when the resin flow is blocked by making the damming pin enter the most, the tip of the damming pin is supported by entering the concave curved surface formed on the contact surface of the runner. And the root portion are supported at both ends, so that distortion, damage or breakage can be prevented.

  Furthermore, in cases other than when the damming pin is most advanced (when the resin flow is interrupted), the tip of the damming pin is a convex curved surface and the runner contact surface is a concave curved surface, so that the resin flow is not retained or turbulent. Since the flow smoothly occurs in a state in which the generation is suppressed, it is possible to suppress the occurrence of failures such as “sink marks” and weld lines on the surface of the molded product.

  According to the second aspect of the present invention, by adjusting the screwing amount or the loosening amount of the damming pin, the flow rate through which the resin can pass through the runner portion can be finely controlled steplessly.

  According to the third aspect of the present invention, the resin flow in the runner portion can be stopped by blocking the inside of the runner portion by making the weir pin enter the runner portion most.

  In the present invention, even when the damming pin is most advanced into the runner portion, the resin is obtained by adopting a configuration such as providing a gap between the side surface of the damming pin and the wall surface in the runner portion. It does not exclude the aspect of reducing the flow without completely stopping it.

  According to the fifth aspect of the present invention, since the resin flow rate is controlled in the runner portion, it can be applied to both hot runner type and open gate type injection molding. In particular, the present invention can be applied to existing injection molding extremely easily and at a lower cost than the technique of adjusting the resin flow rate by controlling the movement of the gate pin disposed inside the nozzle and controlling the gate opening / closing timing.

  The present invention will now be described in more detail with reference to the accompanying drawings.

 FIG. 1 is a partially exploded diffusion perspective view showing one embodiment of a flow control valve in multi-point gate injection molding according to the present invention (one of two flow control valves is shown as an exploded diffusion perspective view), and FIG. FIG. 3 is a schematic sectional view showing another embodiment of the runner contact surface, and FIG. 4 shows a control state of the flow rate through which the resin can pass through the flow control valve shown in FIG. FIG. 4 is a schematic sectional view taken along line IV-IV {(A) shows a fully open state, (B) shows a half-open state, and (C) shows a cut-off state}.

  The flow control valve in the multi-point gate injection molding according to the present invention (hereinafter sometimes simply referred to as a flow control valve) is a multi-point gate injection molding having a plurality of hot runner type or open gate type nozzles for injecting resin. Attached to a mold (not shown), the runner part excluding the corner of the manifold that branches the resin into the cavity (not shown) of the multipoint gate injection mold (not shown) in this embodiment. The weir pins are arranged so as to be able to advance and retreat from the side of the runner portion at an angle substantially perpendicular to the resin flow direction, and the amount of the weir pins entering the runner portion is The flow rate through which the resin can pass through the runner is controlled by adjusting the flow rate.

  As shown in FIGS. 1 and 2, the flow control valve 1 of the present invention is attached to a manifold block 2 to control the flow rate through which resin can pass through a runner portion 21 formed in the manifold 2 from the side. can do. Reference numeral 3 shown in FIGS. 1 and 2 is a sprue bush, reference numeral 31 shown in FIG. 2 is a sprue formed in the sprue bush 3, and reference numeral 23 shown in FIG. is there.

  The flow control valve 11 includes a weir pin 11 into which a tip 11A formed in a convex curved surface enters the runner portion 21 and a guide screw 12 to which the weir pin 11 is screwed and attached via a male screw portion 11B. A guide flange 13 serving as a flange of the damming pin 11 in the manifold block 2, a lock nut 14 for fixing the screwing position of the damming pin 11 to the guide screw 12 in the screwing shaft direction, and a guide A fixing member 15 for fixing the screwing position of the damming pin 11 to the screw 12 from a direction perpendicular to the screwing axis, a metal ring 16 which is a gasket member of the guide flange 13 and the manifold block 2, and a guide A mounting bolt 1 for mounting and fixing the flow control valve 11 to the manifold block 2 through a screw 12 and a through hole formed in the guide flange 13. And, it is composed mainly from.

  The damming pin 11 is moved into the runner by a screwing operation or a loosening operation performed by rotating the hexagonal head 11C with a tool such as a wrench in a state where the fixing by the lock nut 14 and the fixing member 15 is released. The amount of flow through which resin can pass through the runner portion 21 can be adjusted by adjusting the amount of the weir pin 11 entering the runner portion 21 by the advance and retreat of the weir pin 11. Is to control.

  After adjusting the amount of entry of the plurality of (two in this embodiment) weir pins 11 into each runner portion 21 leading to each of the plurality of gates of the multipoint gate, each adjustment position is maintained without any slippage. Each lock pin 11 is fixed by tightening the lock nut 14 and the fixing member 15. The weir pin 11 whose amount of entry has been adjusted by a screwing operation or a loosening operation is very unlikely to shift its adjustment position in normal injection molding, and is fixed by the lock nut 14 and the fixing member 15 in a double manner. The lock nut 14 and the fixing member 15 are not indispensable components in the present invention because they are countermeasures against a triple adjustment position shift.

  In the runner portion 21, a runner contact surface 22 which is a portion with which the tip 11A abuts when the damming pin 11 is most advanced is formed with a concave curved surface that is shaped to receive the convex curved surface of the tip 11A.

  The convex curved surface of the tip 11A and the concave curved surface of the runner contact surface 22 are not limited to a shape that completely coincides, and at least when the damming pin 11 is most advanced, the tip 11A of the damming pin 11 can enter and be supported, The curved surface shape is less likely to cause the resin flow to stay or turbulently flow, but when the damming pin 11 is most advanced, the tip 11A of the damming pin 11A enters the concave curved surface of the runner contact surface 22 in close contact. It is most preferable in terms of the support stability of the tip 11A of the damming pin 11 and the blocking of the resin flow.

Convex surface of the tip 11A, as shown in FIG. 1, Ru convex der hemispherical songs surface as shown in FIGS.

Further, the concave curved surface of the runner contact surface 22, Ru concave der hemispherical songs surface as shown in FIGS.

  In the present specification, the “hemisphere” is not limited to a semispherical sphere in a strict sense, but includes a convex mirror-like convex curved surface and a concave mirror-like concave curved surface that do not reach the hemisphere as illustrated.

  Further, the concave curved surface formed on the runner contact surface 22 may be formed from the runner portion 21 through a stepped portion, for example, as shown in FIG. As shown in FIG. 3B, it may be formed via a tapered portion 22B. The stepped portions such as the straight portion 22A and the tapered portion 22B are preferably within about 2 mm, more preferably within about 1 mm.

  In the present embodiment, the weir pin 11 is made to enter the runner portion 21 most so as to shut off the runner portion 21 and stop the resin flow in the runner portion 21. The invention is not limited to this configuration, and even when the damming pin 11 is most advanced into the runner portion 21, it is between the side surface of the damming pin 11 and the wall surface in the runner portion 21. By adopting a configuration such as providing a gap, it is possible to reduce the resin flow without completely stopping it.

  In addition, the manifold block 2 can adopt a publicly known configuration as a manifold block used for this type of injection molding, and an aspect in which auxiliary devices such as a temperature sensor and a temperature control heater are attached is also included in the present invention. Is done.

  Further, the flow control valve of the present invention can be applied to various multi-point gate injection moldings, but is most preferably applied to either hot runner type or open gate type injection molding.

  Next, based on FIG. 4, the control of the flow rate adjusting valve for adjusting the flow rate through which resin can pass will be described.

  FIG. 4A shows a state in which the amount of entry into the runner portion 21 is minimized by loosening the weir pin 11 (a state in which the weir pin is retracted), that is, the runner portion 21 is fully open. Show.

  FIG. 4B shows a state in which the weir pin 11 is entered from the state of FIG. 4A into the runner portion 21 by a screwing operation until the flow rate through which resin can pass is reduced to about 1/2. The part 21 shows a half-open state.

  4C shows a state in which the weir pin 11 is further advanced by screwing operation until the tip 11A comes into contact with the runner contact surface 22, that is, the runner portion 21 is shut off (fully closed state). .

1 is a partially exploded perspective view showing one embodiment of a flow control valve in multi-point gate injection molding according to the present invention (one of two flow control valves is shown as an exploded diffusion perspective view). 1 is a partially cutaway front view of the flow control valve shown in FIG. Schematic sectional view showing another embodiment of the runner contact surface FIG. 2 is a schematic cross-sectional view taken along the line IV-IV in FIG. 2 showing the control state of the flow rate through which the resin can pass through the flow control valve shown in FIG. 1 ((A) is a full open state, (B) is a half open state, and (C) is a cut off state. Show each}

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flow control valve 11 Damping pin 11A Tip 11B Male thread part 11C Hex head 12 Guide screw 13 Guide flange 14 Lock nut 15 Fixing member 16 Metal ring 17 Mounting bolt 2 Manifold block 21 Runner part 22 Runner contact surface 22A Linear part 22B Taper part 23 Branch part 3 Sprue bush 31 Sprue

Claims (6)

Each runner part except the corner part of the manifold that branches the resin into the cavity of the multi-point gate injection mold has a damming pin from the side of each runner part at an angle substantially perpendicular to the resin flow direction. It is arranged so as to be able to advance and retreat with respect to the inside of the runner part, and the resin passes through each runner part by adjusting the amount of the plurality of damming pins entering each runner part leading to each gate of the multipoint gate. A flow control valve for controlling each possible flow rate,
The weir pin has a hemispherical convex curved surface at its tip,
In each runner portion, a hemispherical concave curved surface is formed that receives the convex curved surface of the tip of the damming pin on the runner contact surface, which is the portion where the tip of the damming pin abuts when the damming pin is most advanced. The flow rate control valve in multi-point gate injection molding, characterized by having a configuration.
The flow control valve in multi-point gate injection molding according to claim 1, wherein the damming pin is configured to adjust the amount of entry into the runner portion in a stepless manner by screwing operation and loosening operation. The flow control valve in the multi-point gate injection molding according to claim 1 or 2, wherein the runner portion is shut off when the damming pin is most advanced. An injection molding machine comprising the flow control valve in the multipoint gate injection molding according to claim 1. The injection molding machine according to claim 4, wherein the injection molding is performed by a hot runner system or an open gate system. An injection molding method performed using the flow control valve in the multipoint gate injection molding according to any one of claims 1 to 3,
Performing screwing operation or loosening operation of the damming pin, each modulate a plurality of ingress of the blocking pin into the runner portion communicating with a plurality of the gates of the multi-point gate, the resin can pass in each runner An injection molding method characterized by controlling each flow rate.

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