JPS593866Y2 - Molding mold for molded products with undercuts - Google Patents

Description

[Detailed description of the invention] This invention is a molding die that is used to form a molded product that has undercuts on both the inside and outside of the molded product in injection molding, injection molding, etc. of elastic materials such as rubber and soft synthetic resin. It is related to.

Here, "inside" and "outside" do not mean "inside" or "outside" with respect to the outer surface or inner surface of the molded product, or the front surface of the molded product itself;
This means that the positional relationship of at least two undercut portions to which this invention is applied is on the inside or outside of the reference plane, assuming an appropriate reference plane in the positional relationship of the core forming the cavity surface of the molding die. , up and down, or left and right.

Furthermore, the assumed reference plane does not necessarily have to be a plane.

Conventionally, it was extremely difficult to form undercuts on both the inside and outside of a molded product, making the mold complex and the process time-consuming.

The mold is divided into a fixed mold, a movable mold, and a core, an undercut is formed by the core, the movable mold is moved back after molding, the mold is opened, the core and the molded product are removed together, and then the core is removed. The core was removed from the molded product by dividing it into parts.

In this case, it was difficult to take out the molded product, the molding operation was complicated, and the molding process also took a long time.

This invention provides a molding die which eliminates the conventional drawbacks, facilitates the removal of a molded product with undercuts formed on both sides of the molded product, and shortens the molding process.

This invention will be specifically explained below based on the drawings.

Figure 1 shows the mold closed after injection molding of an elastic material such as rubber or soft synthetic resin has been completed. 31.32.3
3 is installed to form a cavity 4.

The core 31 forms an undercut portion inside the molded product 6, and a slide pin 51 fixed to the movable mold 2 slidably passes through the core 31.

The slide pin 51 is inserted into a hole drilled in the fixed mold 1 and having an inner diameter larger than the outer diameter of a locking portion 53 at the tip of the slide pin 51.

Note that the operations of the fixed mold 1 and the movable mold 2 may be reversed.

The cores 32 and 33 form an undercut on the outside of the molded product, the core 32 is in contact with the movable mold 2, and the core 33 is in contact with the fixed mold 1.
A slide pin 52, which is installed in contact with the movable mold 2 and is fixed to the movable mold 2, slidably passes through the core 32.

The slide pin 52 is inserted into a hole having an inner diameter larger than the outer diameter of a locking portion 54 at the tip of the slide pin 52, which is formed in a fixed mold with the core 32.

A plurality of slide pins 51 and 52 are arranged in parallel in a direction perpendicular to the plane of the drawing.

The core 33 is rotatably engaged with a rotating shaft 7 fixed to the fixed mold 1, and is biased by a coil spring 8 fitted into the rotating shaft 7 so as to come into close contact with the fixed mold 1.

Although the fixed mold 1 and the movable mold 2 are divided into three parts from the viewpoint of mold production, they may not be divided into three parts.

Next, the operation of this invention will be explained with reference to the drawings.

FIG. 1 shows a state in which rubber or soft synthetic resin has been injected into the cavity 4 and vulcanization or cooling has been completed.

After the molding is completed, the movable mold 2 is moved backward in a conventional manner.

FIG. 2 shows a state in which only the movable mold 2 is open during the process in which the mold is being opened.

Due to the movement of the movable mold 2, the lip 61 of the molded product 6 is moved by the movable mold 2.
It separates from cavity 4 of.

However, the cores 31, 32, and 33 have not yet moved.

At this time, as the movable die 2 retreats, the locking portion 54 of the slide pin 52 comes into contact with the core 32, as shown in FIG.
As the movable mold 2 retreats, the core 32 also begins to retreat.

As the core 32 retreats, the lip 62 of the molded product 6 is elastically deformed upward and separated from the core 32, resulting in the state shown in FIG. 3.

When the movable mold 2 further retreats, the locking portion 53 of the slide pin 51 comes into contact with the core 31, and as the movable mold 2 retreats, the core 31 also begins to retreat, and the core 31. Both cores 32 are moved back.

At this time, since the core 31 forming the inner undercut portion holds the molded product 6 at its tip by the lips 66 and 65, the molded product 6 starts moving while being held by the core 31.

When the molded product 6 starts to move while being held by the core 31, the lip 63 forms an undercut portion with the core 33 and the fixed mold 1, and is also sandwiched between the fixed mold 1 and the core 33. It cannot be elastically deformed.

Therefore, when the molded product 6 starts to separate from the fixed mold 1 and the core 33, the core 33 is pushed upward by the lip 63 and moves toward the movable mold 2 about the rotation shaft 7 against the elasticity of the coil spring 8. The molded product 6 (illustrated by the dotted line in FIG. 4) is easily separated from the fixed mold 1 and the core 33 by rotation.

At this time, the spring strength of the coil spring 8 is such that the molded product 6 can be easily removed, and after the molded product 6 is removed, the core 33 can quickly return to its original state so that it comes into contact with the fixed mold 1.

After the molded product 6 is separated from the fixed mold 1 and the core 33, the movable mold 2 further moves back, opens the mold to a width that allows the molded product 6 to be taken out from the core 31, and then stops.

After the mold has stopped, the molded product 6 is separated from the core 31,
Take it out.

After taking out the molded product 6, the movable mold 2 moves forward, and in the opposite manner to the above, the mold is closed and rubber or soft synthetic resin is injected into the cavity 4.

Repeat this cycle.

This idea allows molded products with undercuts on both the inside and outside to be easily molded and taken out by a single mold opening/closing process as described above, and prevents sac cavities from occurring without damaging the undercuts of the molded product. The mold can be taken out and the mold can be opened and closed automatically, which not only significantly shortens the molding process, but also makes it possible to mold multiple pieces, which was previously difficult due to the long time required, greatly improving productivity. .

Furthermore, work safety is improved because there is no need to take out the core.

[Brief explanation of the drawing]

Figures 1 to 4 are partial cross-sectional views of the mold showing each molding process using the mold of this invention, with Figure 1 showing the closed state of the mold, Figures 2 and 3. 4 shows the process of opening the mold, and FIG. 4 is a partial sectional view when the mold is completely opened. 1... Fixed type, 2... Movable type, 4... Cavity, 6... Molded product, 7... Rotating shaft, 8... Spring, 3
1.32.33... Core, 51.52... Slide pin.

Claims (1)

[Scope of utility model registration request] Molded product 6 with undercuts on both inside and outside
In the mold for molding, a cavity 4 is formed by a fixed mold 1, a movable mold 2, and a plurality of cores 31, 33, one core 31 forms an undercut part on one side, and the mold is opened. At the same time, the molded product 6 is released from the fixed mold 1 together with the core 31 and held by the core 31, and the slide pin 51 fixed to the movable mold 2 is moved to the core 31. The other core 33 forms an undercut on the other side of the molded product 6, and the core 3
3 has an undercut portion which is rotatably engaged around a rotation shaft 7 fixed to the fixed mold 1, and the core 33 is urged against the fixed mold 1 by a spring 8. mold for molded products.