JPH0545449Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mold used for injection molding, transfer molding, etc., and more specifically to a mold having a mold release mechanism for an undercut portion.

[Prior art] As a mold with a mold release mechanism for the undercut part,
For example, as disclosed in Japanese Patent Publication No. 59-17932, many combinations of a slide core and an extrusion mechanism have been proposed. In such molds, the slide core is usually provided on the movable mold side. However, depending on the shape of the product, undercut portions may exist on both sides of the molded article. In such a case, even if a slide core is provided only on the movable mold, it is difficult to release the undercut portion on the fixed mold side.

[Problems to be Solved by the Invention] Therefore, a mold as shown in FIG. 6 can be considered as a mold for molding a molded body having undercut portions on both sides. This mold has a back plate of 100
, a fixed mold 200 , a movable mold 300 , and a slide core 400 . The back plate 100 has an inner slide plate 110 that forms a part of the mold surface.
is held through the fixed mold 200. And the slide core 400 is the inner slide core 110
is engaged with the T-groove 410, and is slidably held by the fixed mold 200. In addition, fixed type 20
0, an undercut portion 500 is molded using a movable mold 300 and a slide core 400.

To explain the operation of the mold configured in this way, first, the space between the back plate 100 and the fixed mold 200 is opened. Then, the slide core 400 is connected to the spring 12
The inner slide roller 1 is pressed against the fixed mold 200 by a biasing force of 0, guided by the inclined T-groove 410.
10 and the movable mold 300.
As a result, the undercut portion 500 is removed from the slide core 400.

Then, the molds are opened between the fixed mold 200 and the movable mold 300, and the molded body is released from the fixed mold 200. The molded body is then released from the movable mold 300 by driving an extrusion pin (not shown) or the like. Note that the undercut portion 510 on the opposite side is the movable mold 30.
Since it is on the 0 side, it can be easily released from the mold using the conventional slide core method.

However, this mold also has a problem in that the number of parts such as the back plate is large, and the number of man-hours for machining and adjusting the mold is large. Furthermore, the mold becomes large, which may cause problems in terms of space. Furthermore, since it is necessary to open and close between the back plate and the fixed mold, it is necessary to move the nozzle of the injection molding machine forward and backward, causing a problem of cycle loss time. Furthermore, the molded body may adhere to the slide core and be removed. In this case, the molded body remains on the fixed mold side, making it difficult to take it out automatically.

The present invention has been developed in view of these circumstances, and it is an object of the present invention to enable the undercut portion to be treated with a simple configuration.

[Means for Solving the Problems] A molding die of the present invention that solves the above problems includes a movable mold, a first guide surface extending in a direction inclined with respect to the mold opening direction of the movable mold, and a first guide surface extending in the mold opening direction. a fixed mold having an extending second guide surface; a first core held by the fixed mold and movable while being guided by the first guide surface; and a first core held by the fixed mold and protruding from the mold surface of the fixed mold. a second core that is held by a fixed mold and is movable while being guided by a second guide surface and forms an undercut portion of the molded body together with the first core and the movable mold; When the mold is opened, the second core is guided by the second guide surface, moves in the mold opening direction, and holds the undercut portion together with the movable mold.

[Function] In the molding die of the present invention, when opening the mold, the movable mold is first driven in the mold opening direction to open the mold. Then, due to the biasing force of the biasing member, the first core is guided by the first guide surface, moves in a direction inclined from the mold opening direction, and protrudes from the mold surface of the fixed mold. By moving the first core in a direction inclined from the mold opening direction in this manner, it is possible to release the undercut portion from the first core. However, in that case, the molded body may adhere to the first core and be removed. It is not preferable that the molded body be removed by the first core, which is a part of the fixed mold.

Therefore, the mold of the present invention is provided with a second core. That is, when the mold is opened, the second core moves in the mold opening direction while being guided by the second guide surface. Therefore, the first core and the second core move relative to each other so as to gradually move away from each other in the direction along the mold surface. This allows the undercut portion to be released from the first core while maintaining the undercut portion held between the second core and the movable mold, and prevents the molded object from being taken by the first core. Ru.

[Example] Hereinafter, this will be explained in detail using examples.

FIGS. 1 to 5 show a mold according to an embodiment of the present invention. This mold is a mold for resin injection molding.

This mold includes a movable mold 1, a fixed mold 2, a first core 3, and a second core 4.

The first core 3 is movably held by the fixed mold 2. The first core 3 has an angle θ with respect to the mold opening direction.
A first guide pin 30 that is inclined by 1 is fixed, and the other end of the first guide pin 30 is inserted into a through hole 20 provided in the fixed mold 2. and through hole 20
A stopper 31 having a diameter larger than the diameter of the through hole 20 is provided on the first guide pin 30 that comes out from the first guide pin 30 .
The amount of movement of core 3 is regulated. and fixed type 2
A spring 32 is interposed between the first core 3 and the first core 3;
The first core 3 is urged in the direction of protruding from the mold surface of the fixed mold 2.

Here, the moving direction of the first core 3 is determined by the direction in which the first guide pin 30 and the through hole 20 are in sliding contact, and the direction in which the first core 3 and the fixed mold 2 are in sliding contact.
In this embodiment, since the axial direction of the through hole 20 and the direction of the sliding surface 22 of the fixed mold 2 with which the first core 3 slides are both inclined by an angle θ from the mold opening direction, the first core 3 is movable in a direction inclined by an angle θ from the mold opening direction. That is, the inner peripheral surface of the through hole 20 and the sliding surface 22 constitute a first guide surface, and the first core 3 is configured to move while being guided by the first guide surface.

The second core 4 is connected to the first core 4 as shown in the cross section in FIG.
The first core 3 and the second core 4 are configured to engage with the core 3 through a T-slot 40 and to be relatively movable. Further, the second core 4 is pivotally supported by a second guide pin 21 fixed to the fixed mold 3 and extending in the mold opening direction, so as to be movable in the mold opening direction. That is, the outer peripheral surface of the second guide pin 21 constitutes a second guide surface.

And the movable mold 1, the first core 3 and the second core 4
Thus, a cavity for forming the undercut portion 50 of the molded body 5 is formed. Note that since the molded body 5 has a second undercut portion 51 extending on the opposite side to the undercut portion 50, the movable mold 1 has a third undercut portion 51.
As shown in the figure, a mold release mechanism 10 using a known inclined core method is provided.

The operation of the mold of this embodiment configured as described above will be explained below.

When injection of the resin from the injection molding machine is completed and the molded body 5 is cooled and solidified, the movable mold 1 moves downward in FIG. Then, the first core 3 moves together with the movable mold 1 due to the urging force of the spring 32. At this time, the first core 3 is guided by the inner peripheral surface of the through hole 20 and the sliding surface 22, and moves in a direction inclined by an angle θ from the mold opening direction.

At this time, since the second core 4 is engaged with the first core 3, it tries to move together with the first core 3, but since the lateral movement in the figure is restricted by the second guide pin 21, The two cores 4 move only in the mold opening direction. Then, the first core 3 moves relative to the second core 4 due to the T-groove 40, and moves in a direction away from the second core 4. As a result, as shown in FIG. 4, the undercut portion 50 is released from the first core 3.

In this state, the movement amount of the first core 3 is restricted by the stopper 31, and the movement of the second core 4 is also stopped together with the first core 3. When the movable mold 1 is further opened, the molded body 5 becomes attached only to the movable mold 1, as shown in FIG. Then, the second undercut portion 51 on the opposite side is released from the mold by a known mold release mechanism 10, and the molded body 5 is released from the movable mold 1 and taken out by driving an ejector pin (not shown).

To move on to the next molding process, when the movable mold 1 moves in the tightening direction and presses the second core 4, the T-groove 4
As a result, the first core 3 slides. Then, the second core 4 further resists the biasing force of the spring 32.
By pressing , the state shown in FIG. 1 is achieved and mold clamping is completed.

[Effects of the invention] Therefore, according to the molding mold of the present invention, the mold release mechanism of the undercut portion on the fixed mold side has a simple structure, so it is compact, and the number of man-hours for machining the mold is reduced. Man-hours for alignment adjustment are reduced. Furthermore, since there is only one mold dividing surface, it is possible to open and close the mold while keeping the nozzle of the injection molding machine in contact with it, shortening cycle time and improving productivity.

[Brief explanation of the drawing]

Figures 1 to 5 relate to a molding die according to an embodiment of the present invention; Figure 1 is a cross-sectional view of the mold when the mold is clamped;
3 and 3 are sectional views of essential parts thereof, and FIGS. 4 and 5 are sectional views thereof when the mold is opened. FIG. 6 is a cross-sectional view of an example of a mold for molding a molded article having undercuts on both the front and back sides, which was devised prior to the invention. DESCRIPTION OF SYMBOLS 1... Movable type, 2... Fixed type, 3... First core, 4... Second core, 5... Molded body, 20... Through hole (first guide surface), 21... Second guide Pin (second guide surface), 22... sliding plane (first guide surface), 30... first guide pin, 31... stopper, 32... spring (biasing member), 40...
T groove, 50... undercut part.

Claims (1)

[Claims for Utility Model Registration] A movable mold, a fixed mold having a first guide surface extending in a direction oblique to the mold opening direction of the movable mold and a second guide surface extending in the mold opening direction, and the fixed mold. a first core held by the mold and movable while being guided by the first guide surface; a biasing member held by the fixed mold and urging the first core in a direction to protrude from the mold surface of the fixed mold; , a second core that is held by the fixed mold and movable while being guided by the second guide surface and forms an undercut portion of the molded article together with the first core and the movable mold, and when the mold is opened, the second core A molding die characterized in that the core is configured to move in the mold opening direction while being guided by the second guide surface and hold the undercut portion together with the movable mold.