JPH05329893A - Injection mold - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a molding die that allows a molded product having an undercut portion to be easily separated from the mold when the mold is opened. [Structure] The slide core 3 is provided with a mold releasing pin 7 and a pressing pin 13 which engages with the mold releasing pin 7. The pressing pin 13 has an inclined surface 16 at its tip, and when the mold is closed, The inclined surface 16 is fitted along the inclined surface 18 of the fitting insertion hole 17 provided in the release pin 7 to retract the release pin 7,
When the mold is opened, the inclined surface 16 of the tip end portion of the pressing pin 13 retracts along the inclined surface 18 of the fitting insertion hole 17 of the release pin 7, and the tip end portion 10 of the slide core 3 is moved by the restoration of the coil spring 9. The undercut portion 5 is released from the slide core 3 by projecting it from the mold surface of the slide core 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die which allows a molded product having an undercut portion to be easily separated from the mold when the mold is opened.

[0002]

2. Description of the Related Art In order to separate a molded product having an undercut portion from the mold when the mold is opened, a slide core is provided on the mold to which the molded product is attached, and the undercut portion is molded by this slide core. , When opening the mold, slide the slide core to remove the undercut part,
Next, the ejector plate is moved forward, and the molded product is pressed by the protruding pin fixed to the ejector plate to release the molded product (actual fair 2
-8740).

[0003]

However, when the undercut portion of the molded product becomes relatively large, the mold surface for molding the undercut portion formed on the slide core becomes a deep concave portion, so that the mold opening occurs. At that time, there is a problem that the undercut portion cannot be removed only by sliding the slide core along the inclined guide pin.

The present invention has been made in view of the above-mentioned problems. Even when the mold surface for molding the undercut portion formed in the slide core is a deep recess, the undercut portion is formed. An object of the present invention is to provide an injection molding die that can easily separate the molded article that it has from the mold when the mold is opened.

[0005]

An injection molding die according to the present invention is an injection molding die in which a mold cavity that matches a desired shape of a molded article is formed by closing a mold. The mold on the side of the mold is provided with a slide core that has a mold surface that molds the undercut part and that slides along the inclined guide pin. The slide core is provided with a mold release pin for the molded product. When the mold is closed, the pin retreats due to compression of the elastic body and the tip part forms part of the mold surface.
When the mold is opened, the elastic body is restored so that it projects from the mold surface and presses the undercut part of the molded product in the direction to separate it from the slide core.The slide core is provided with a pressing pin that engages with the mold release pin. The pressing pin has an inclined surface at the tip, and when the mold is closed, this inclined surface is fitted along the inclined surface of the fitting insertion hole provided in the mold releasing pin to retract the mold releasing pin. When the mold is opened, the inclined surface of the tip of the pressing pin recedes along the inclined surface of the insertion hole of the mold release pin, and the elastic body provided on the mold release pin restores the mold release pin. The slide core is made to project from the mold surface, and with such a structure, a molded product having an undercut portion can be easily separated from the mold when opening the mold. is there.

[0006]

According to the present invention, when the moving side mold, the fixed side mold and the slide core are closed, the elastic body of the pressing pin is compressed and the inclined surface of the tip end of the pressing pin is fitted with the releasing pin. The mold release pin is retracted by being fitted along the inclined surface of the insertion hole, and the tip of the mold release pin forms a part of the mold surface. A molding material having a desired undercut portion is molded by injecting a molding material such as synthetic resin or rubber into the mold cavity thus formed.

After molding, when the movable side mold is separated from the fixed side mold by opening the mold, the elastic body provided on the pressing pin is restored,
The inclined surface of the tip of the pressing pin retracts along the inclined surface of the insertion hole of the mold release pin, the mold release pin projects from the mold surface of the slide core, and the undercut part of the molded product separates from the slide core. Since the pressing is performed in the direction in which the molding is performed, the undercut portion of the molded product is reliably separated from the slide core, and thus the molded product can be easily released from the mold.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an injection molding die according to the present invention will now be described with reference to the drawings.

FIG. 1 is a sectional view showing the state of the injection mold when the mold is closed, and FIG. 2 is a sectional view showing the state of the injection mold when the mold is open. The injection mold comprises a movable mold 1, a fixed mold 2 and a slide core 3, which are closed to form a mold cavity for molding a molded product 4 conforming to a desired molded product shape. To be done.

The moving side mold 1 is a mold on the side to which the molded product 4 is attached by opening the mold, and the slide core 3 provided on the moving side mold 1 has a mold surface for molding the undercut portion 5. The slide core 3 has an engaging portion 8 that is slidable with the fixed side die 2, and slides along the inclined guide pin 6 while maintaining the engaged state at the engaging portion 8 at the beginning of mold opening. To be done. The slide core 3 is provided with a mold release pin 7 for the molded product 4.

The releasing pin 7 is fitted in a fitting hole 11 formed in the slide core 3, and one end of a coil spring 9 is in contact with the rear end of the releasing pin 7, The other end is in contact with the plug 12 fitted in the fitting hole 11. The mold releasing pin 7 is retracted by the compression of the coil spring 9 when the mold is closed, and the tip portion 10 forms a part of the mold surface. When the mold is opened, the coil spring 9 is restored to project from the mold surface. Undercut part 5 of item 4
Is pushed in a direction of separating from the slide core 3.

The slide core 3 is provided with a pressing pin 13 which engages with the releasing pin 7. The pressing pin 13 is fitted in a fitting hole 14 formed in the slide core 3,
A coil spring 15 is wound around the pressing pin 13 and is held by the fitting hole 14 and the base 131. The pressing pin 13 has an inclined surface 16 at the tip thereof, and when the mold is closed, the inclined surface 16 is fitted along the inclined surface 18 of the fitting insertion hole 17 provided in the mold releasing pin 7 for releasing. Pin 7
Retreat. At this time, the coil spring 15 around the pressing pin 13 is in a state of being compressed by the pressure when the mold is closed.

When the mold is opened, the base portion 1 of the pressing pin 13 is opened.
Since 31 is separated from the mold surface of the fixed mold 2, the coil spring 15 is restored, whereby the inclined surface 16 of the tip end portion of the pressing pin 13 recedes along the inclined surface 18 of the fitting insertion hole 17 of the release pin 7. It is supposed to do.

The operation of the above injection molding die will be described. As shown in FIG. 1, the movable side mold 1, the fixed side mold 2, and the slide core 3 are closed. When the mold is closed, the base 131 of the pressing pin 13 comes into contact with the mold plate of the fixed-side mold 2, the coil spring 15 is compressed, and the inclined surface 16 at the tip end is the inclined surface 18 of the fitting insertion hole 17 of the mold releasing pin 7. The mold release pin 7 is retracted by being inserted along the above, and the tip end portion 10 of the mold release pin 7 forms a part of the mold surface. A molding material such as synthetic resin or rubber is injected into the mold cavity thus formed to mold a desired molded product 4.

As shown in FIG. 2, when the movable side mold 1 is separated from the fixed side mold 2 by opening the mold after molding, the slide core 3
Moves away from the fixed mold 2 together with the movable mold 1, is guided by the inclined guide pin 6, and moves relative to the movable mold 1 in the direction perpendicular to the moving direction. At this time, due to the restoration of the coil spring 15, the inclined surface 16 of the tip portion of the pressing pin 13 retreats along the inclined surface 18 of the fitting insertion hole 17 of the mold releasing pin 7, and the restoring force of the coil spring 9 causes the mold releasing. The pin 7 slides in the fitting hole 11 of the slide core 3, and the tip portion 10 thereof projects from the mold surface of the slide core 3. As a result, the undercut portion 5 of the molded product 4 is pressed in the direction of separating from the slide core 3, and the undercut portion 5 of the molded product 4 can be easily released from the slide core 3.

Next, the formed article 4 is separated from the fixed side mold 1 by a not shown ejection pin or the like, and the mold release is completed. After the release of the molded product 4 is completed, the mold is closed,
The same operation is repeated.

[0017]

Since the injection molding die of the present invention has the above-mentioned structure, the elastic body provided on the pressing pin is restored by opening the mold, and the pressing pin has the inclined surface at the tip end portion. Since the mold release pin retreats along the inclined surface of the insertion hole, the mold release pin projects from the mold surface of the slide core, and the undercut portion of the product is pressed in the direction of releasing from the mold, Can be easily released.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing a state of a mold for injection molding according to the present invention when the mold is closed.

FIG. 2 is a cross-sectional view of essential parts showing a state when the mold for injection molding according to the present invention is opened.

[Explanation of symbols]

 1 Moving Side Mold 2 Fixed Side Mold 3 Slide Core 4 Molded Product 5 Undercut Part 6 Inclination Guide Pin 7 Release Pin 8 Engagement Part 9 Coil Spring 10 Tip Part 11 Fitting Hole 12 Plug 13 Pressing Pin 15 Coil Spring 16 inclined surface 17 insertion hole 18 inclined surface

Claims (1)

[Claims] 1. A mold surface for forming an undercut portion on a mold on a side to which a molded product adheres when a mold is opened in an injection molding mold in which a mold cavity suitable for a desired molded product shape is formed by closing the mold. Is provided with a slide core that slides along the inclined guide pin, the slide core is provided with a mold release pin, and the mold release pin retracts due to compression of an elastic body when the mold is closed. The tip part forms a part of the mold surface, and when the mold is opened, the elastic body is restored so that it projects from the mold surface and presses the undercut part of the molded product in the direction to separate it from the slide core. Is provided with a pressing pin that engages with the releasing pin, and the pressing pin has an inclined surface at the tip, and when the mold is closed, this inclined surface is the inclined surface of the fitting insertion hole provided in the releasing pin. Is inserted along with and retract the release pin, When the mold is opened, the inclined surface of the tip of the pressing pin recedes along the inclined surface of the insertion hole of the release pin, and the release pin slides by restoring the elastic body provided on the release pin. An injection molding die characterized in that it is projected from the die surface of the core.