JP3235230B2 - Mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold having a submarine gate.

[0002]

2. Description of the Related Art A conventional structure of such a molding die will be described with reference to FIGS. First, in FIG.
Is moved in the direction of arrow A with respect to the fixed mold 2 at the time of releasing the mold.
The runner 3 and the cavity 4 are formed in the a and 2a, and the movable mold 1 is provided between the runner 3 and the cavity 4.
Are communicated with each other by a so-called submarine type gate section 5 which penetrates through.

[0003] The molten resin injected from an injection molding machine (not shown) on the fixed mold 2 side is injected from the runner section 3 into the cavity section 4 via the gate section 5. By solidifying the resin in the part 3, the cavity part 4, and the gate part 5, the runner 6, the product 7, and the gate 8 are respectively formed.

The movable die 1 is provided with an ejector pin 9 for projecting the runner 6 in addition to an ejector pin 9 for projecting the product 7, and when the movable die 1 is released, the ejector pins 9, 10 are deflected. The gate 8 protrudes in the direction of the arrow A and is automatically cut off from the product 7 as shown in FIG.

[0005]

However, this type of mold having a submarine type gate portion 5 has a gate 8
Is forcibly pulled out of the gate portion 5, and thus the behavior of the gate 8 in the gate portion 5 tends to be unstable. As a result, particularly at the moment when the gate 8 protrudes from the gate portion 5, as shown in FIG. 8, there is a possibility that the tip 8a of the fragile gate 8 comes into contact with the wall surface of the gate portion 5 and breaks. When the tip 8a of the gate 8 is broken in this way, the broken tip 8a is sandwiched between the movable mold 1 and the fixed mold 2 to cause improper mold clamping or enter the gate portion 5 to enter the gate. There is a possibility that the portion 5 may be closed and a resin injection failure may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a molding die which can prevent a tip of a gate from being broken when a gate formed by a submarine type gate is forcibly removed. It is to provide.

[0007]

A molding die according to the present invention is provided on a runner portion and a cavity portion formed on a dividing surface between a fixed die and a movable die, and on one of the fixed die and the movable die. A submarine-type gate portion communicating between the runner portion and the cavity portion, and an ejector forcibly removing a gate formed by solidifying the resin of the gate portion by projecting a runner formed by solidifying the resin of the runner portion. And a groove extending from the runner to an intermediate portion of the gate and being opened at the dividing surface.

In this case, a receiving portion forming portion for forming a receiving portion which comes into contact with the peripheral wall of the gate portion when the gate is forcibly pulled out may be provided in the vicinity of the front end portion of the gate portion. ).

[0009]

According to the first aspect of the present invention, when the ejector pin is projected and the runner is projected, the gate is projected from the gate so that the tip portion passes through the groove. Therefore, it is possible to prevent the tip of the gate from contacting the peripheral wall of the gate at the moment when the gate protrudes from the gate.

According to the second aspect of the present invention, the receiving portion is formed near the tip of the gate, and when the gate is forcibly pulled out, the receiving portion comes into contact with the peripheral wall of the gate portion. As a result, while the gate protrudes from the gate portion, the behavior of the gate in the gate portion is stabilized, so that the tip of the gate can be more reliably prevented from contacting the peripheral wall of the gate portion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 3 showing the entire configuration, a molding die 11 includes a fixed die 12 and a movable die 13, and an injection molding machine (nozzle 1) is provided on the fixed die 12 side.
4 only), and the movable mold 13 moves in the direction of arrow A with respect to the fixed mold 12 at the time of mold release. Then, the dividing surface 12 between the fixed mold 12 and the movable mold 13
As shown in FIGS. 1 and 2, a runner portion 15 and a cavity portion 16 are formed in a and 13 a, and the runner portion 15 and the cavity portion 16 are communicated by a gate portion 17.

The gate portion 17 penetrates the movable mold 13 and has a predetermined angle θ (30 to
60 °), which is a so-called submarine type (tunnel type). The gate portion 17 has a groove extending from the runner portion 15 to an intermediate portion of the gate portion 17 and opened at the dividing surface 13a. 18 are provided. Moreover, the lower surface of the gate portion 17 except for the vicinity of the tip portion 17a is swelled downward in an arc shape as shown in FIG.
As shown in FIG. 2, the rear side portions are bulged in an arc shape in the left and right directions on the paper, and these bulge portions function as receiving portion forming portions 19.

As shown in FIG. 3, the movable die 13 is provided with an ejector plate 20. The ejector plate 20 has ejector pins 21 and 22.
Is installed. And the ejector pin 21
As the ejector plate 20 slides in the direction of the arrow A, the ejector plate 20 projects into the cavity 16 and the ejector pin 22 projects into the runner 15.

Next, the operation of the above configuration will be described. First, in FIG. 3, when the molten resin is injected from the nozzle 14, the molten resin flows from the runner 15 to the gate 17.
Through the cavity 16. And FIG.
As shown in FIG. 5, the resin in the runner portion 15, the cavity portion 16, the gate portion 17, the groove portion 18, and the receiving portion forming portion 19 is solidified, so that the runner 23, the product 24, and the gate 2 are respectively formed.
5, a convex portion 26 and a receiving portion 27 are formed.

Thereafter, when the movable die 13 moves in the direction of arrow A, the ejector plate 20 slides in the direction of arrow A at a predetermined timing as shown in FIG. , Ejector pin 2
2, the runner 23 is protruded, and as shown in FIG.
The tip 25 a of the gate 25 is automatically cut off from the product 24.

Then, as shown by a two-dot chain line in FIG. 5, first, the upper surface portion 25b and the receiving portion 27 of the gate 25 contact the upper wall 17b of the gate portion 17 and the lower surface portion of the receiving portion forming portion 19, respectively. Next, the upper surface portion 25b of the gate 25 moves along the upper wall 17b of the gate portion 17. Therefore, the behavior of the gate 25 is stabilized in the gate section 17,
In a state where the distal end portion 25a does not come into contact with the peripheral wall of the gate portion 17, it reaches the position indicated by the solid line. As shown in FIG. 6, the tip 25a of the gate 25 passes through the groove 18 opened at the dividing surface 13a and protrudes from the gate 17.

According to the above embodiment, the gate portion 17 is provided with the groove portion 18 extending from the runner portion 15 to an intermediate portion of the gate portion 17 and opened at the dividing surface 13a.
5 protrudes from the gate portion 17 such that the tip portion 25a passes through the groove portion 18. As a result, it is possible to prevent the tip portion 25a of the gate 25 from breaking due to contact with the peripheral wall of the gate portion 17, thereby preventing poor mold clamping and resin injection caused by the breakage of the gate tip portion. it can.

Furthermore, in the above embodiment, the receiving portion 27 is formed in the gate 25 by providing the receiving portion forming portion 19 in the vicinity of the tip portion 17a of the gate portion 17, so that when the gate 25 is forcibly removed. The receiving portion 27 abuts on the peripheral wall of the gate portion 17, and the behavior of the gate 25 in the gate portion 17 is stabilized. As a result, it is possible to prevent the tip portion 25a from coming into contact with the peripheral wall of the gate portion 17 while the gate 25 is protruding from the gate portion 17, and,
Breakage of the tip portion 25a of the gate 25 can be more reliably prevented.

Although the gate 17 is provided on the movable mold 13 in the above embodiment, a gate may be provided on the fixed mold 12.

[0020]

As is apparent from the above description, the molding die of the present invention has the following excellent effects. According to the first aspect of the present invention, since the gate portion is provided with the groove portion extending from the runner portion to the middle portion of the gate portion and being opened at the division surface, the gate is formed so that the tip portion passes through the groove portion. To protrude from the gate.
As a result, it is possible to prevent the tip portion of the gate from being broken due to contact with the peripheral wall of the gate portion, and further, it is possible to prevent mold clamping failure and resin injection failure caused by the breakage of the gate tip portion.

According to the second aspect of the present invention, the receiving portion is formed in the gate by providing the receiving portion forming portion near the front end portion of the gate portion. Abuts on the peripheral wall of the gate portion, and the behavior of the gate in the gate portion is stabilized. As a result, it is possible to prevent the tip of the gate from coming into contact with the peripheral wall of the gate in the process of protruding the gate from the gate, and it is possible to more reliably prevent the tip of the gate from being broken.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing the vicinity of a gate according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II in FIG.

FIG. 3 is a longitudinal sectional front view showing the entire configuration.

FIG. 4 is a view corresponding to FIG. 3, showing a state at the time of mold release.

FIG. 5 is a view corresponding to FIG. 1, showing a state when the gate is forcibly removed.

FIG. 6 is a cross-sectional view taken along a roll line in FIG. 5;

FIG. 7 is a diagram corresponding to FIG. 1 showing a conventional example.

FIG. 8 is a diagram corresponding to FIG. 5;

[Explanation of symbols]

11 is a molding die, 12 is a fixed die, 13 is a movable die, 12a,
13a is a dividing surface, 15 is a runner portion, 16 is a cavity portion, 17 is a gate portion, 18 is a groove portion, 19 is a receiving portion forming portion, 22 is an ejector pin, 23 is a runner, 25 is a gate, and 27 is a receiving portion. .

Claims (2)

(57) [Claims] 1. A runner and a cavity formed on a dividing surface between a fixed die and a movable die, and communicating between the runner and the cavity provided on one of the fixed die and the movable die. Submarine type gate,
An ejector pin forcibly removing a gate formed by solidification of the resin of the gate portion by protruding a runner formed by solidification of the resin of the runner portion, wherein the gate portion is provided in the middle of the gate portion from the runner portion. A mold extending to a site and provided with a groove that is opened at the dividing surface. 2. A receiving portion forming portion for forming a receiving portion which comes into contact with a peripheral wall of the gate portion when the gate is forcibly pulled out is provided near a tip portion of the gate portion. The mold according to 1.