JPH08112841A - Injection mold - Google Patents

Abstract

PURPOSE: To provide an injection mold capable of molding a molded product having a good undercut part by smoothly treat the undercut part by a slide block without using an inclined pin. CONSTITUTION: In an injection mold, a cavity 5 for a molded product having an undercut part 51 is provided between a movable template 1 and a fixed template 2. Two divided slide blocks 3 for treating the undercut part 51 and a tensile means allowing mutually attracting force to act on the slide blocks 3 are provided to the movable template 1 and, further, the locking block 4 penetrating into the gap between the slide blocks 3 to fix the slide blocks is provided to the fixed template 2 and the slide blocks 3 are moved in a direction of coming into contact with each other or separating from each other by the locking block 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold, and more particularly to an injection mold for treating an undercut portion of a molded product with a slide core.

[0002]

2. Description of the Related Art Conventionally, the processing of an undercut portion provided on the inside of a molded product is performed by a tilting forward operation at the time of mold opening of a tilting pin erected from a protruding plate provided on the movable side mold plate side. (See Japanese Patent Laid-Open No. 4-18837).

[0003]

However, in the treatment of the undercut portion by the above-mentioned conventional inclined pin,
When the depth of the molded product is deep and the undercut portion is deep inside the side surface of the molded product, the tilt pin erected from the movable mold plate side becomes longer and the tilt pin is tilted. Depending on the angle, the lower end side of the inclined pin interferes with the cavity for forming the side surface of the molded product, so that it becomes impossible to perform the processing of the undercut portion by means of the inclined pin.

As a remedy for the above-mentioned undercut portion, a means of forming another undercut portion by adhering another part to the undercut portion of the molded product to form another undercut portion is used. However, this work requires extra man-hours and costs, and there is a problem in that the strength and durability of the undercut portion due to adhesion remain and the cost rises.

The present invention has been made in view of the above problems, and an object of the present invention is to solve these problems and use a slide block to prevent under-tilt. The present invention provides an injection molding die capable of smoothly processing a cut portion and molding a molded product having a good undercut portion.

[0006]

In the injection molding die of the present invention, an injection molding die provided with a cavity of a molded product having an undercut portion between a movable mold plate side and a fixed mold plate side, The movable side mold plate is provided with a two-divided slide block for treating the undercut portion, and a tension means for exerting a force in the mutually attracting directions on the two divided slide blocks. A locking block is provided to fix the slide block by dividing the slide block into two parts, and the locking block moves the slide blocks in a direction of abutting or separating from each other. And

[0007]

In the injection molding die of the present invention, the slide block divided into two is provided in the undercut portion of the cavity, and the slide block divided into two is the locking block and the tension means provided in the slide block. Thus, the undercut portions are smoothly processed because they are opened and closed so as to come into contact with each other or separate from each other, and a molded product having a good undercut portion can be molded.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] FIG. 1 is a cross-sectional view showing an example of an injection molding die of the present invention, in which a molded product is a cylindrical body having a deep depth and an undercut portion is provided at an end portion at the back. , Showing a mode in which the die is closed and the undercut portion is formed by the slide block. In FIG. 1, a movable mold plate 1 of a mold including a movable mold plate 1 and a fixed mold plate 2 has a fixed-side mold plate 2-side end which is divided into two slides for processing an undercut portion. The blocks 3 and 3 are provided symmetrically. Both ends of the slide blocks 3 and 3 are fixed symmetrically in the hollow portions 31 and 31 and springs 32, which are tension means, are attached to the slide blocks 3 and 3 so that tension is applied so that the slide blocks 3 and 3 pull each other. Is being hung up.

The fixed-side mold plate 2 is provided with a locking block 4 which can be moved in and out between the slide blocks 3 and 3, and the sliding blocks 3 and 3 divided by the locking block 4 are separated from each other. It is designed to be opened and closed in the direction of contact or separation.

In FIG. 1, the locking block 4 is separated between the slide blocks 3 and 3, and undercut portions 51 and 51 of the cavity 5 are formed in this state. Therefore, when the molten resin is injected in the mold closed state, the molten resin fills the cavity 5 and an undercut is formed in the molded product.

[Operation of Embodiment] FIG. 2 is a cross-sectional view showing a mode in which the injection molding die shown in FIG. 1 is opened. When the injection and molding of the molten resin are completed, the mold is opened and the undercut portion is formed. It shows a mode in which the processing of (1) is performed.

In FIG. 2, when the movable side mold plate 1 enters the mold opening and starts to retreat, the slide blocks 3 and 3 released from the locking and restraining by the locking block 4 move toward each other due to the tension of the spring 32. Start moving. The slide blocks 3 and 3 move toward each other, and finally reach a contact state as shown in the figure.

Therefore, the undercuts 51a and 51a formed on the molded product 5a gradually move away from the undercut portions 51 and 51 of the cavity 5, and when the mold opening is completed, the undercuts 51a and 51a are completely withdrawn and smooth. By releasing the mold, the undercut process is completed and the molded product can be taken out.

In this embodiment, the case where the molded product is a tubular body and the undercut portion is provided inside the inner end has been described, but the shape of the molded product and the portion where the undercut portion is provided are The present invention is not limited to this, and is particularly suitable for application when it is difficult to process the undercut portion with the inclined pin.

[0015]

In the injection molding die of the present invention, the undercut portion of the cavity is provided with the slide block divided into two, and the slide block divided into two is provided in the locking block and the slide block. Since the tension means opens and closes in a direction in which they come into contact with each other or separate from each other, the undercut portion is smoothly processed, and a molded product having a good undercut portion can be molded. Therefore, it can be suitably used as an injection mold for a molded product having an undercut portion.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an injection molding die of the present invention.

FIG. 2 is a cross-sectional view showing a mode in which the injection molding die shown in FIG. 1 is opened.

[Explanation of symbols]

 1 Movable Side Template 2 Fixed Side Template 3 Slide Block 4 Locking Block 5 Cavity 5a Molded Product 31 Cavity 32 Spring 51 Undercut 51a Undercut

Claims (1)

[Claims] 1. An injection molding die having a cavity for a molded product having an undercut portion between a movable side mold plate side and a fixed side mold plate, wherein the movable side mold plate is treated with an undercut part. Divided slide block and this 2
The divided slide block is provided with a tension means for exerting a force in the direction of attracting each other, and further, the fixed-side template is provided with a locking block for fixing the slide block by splitting into two divisions of the slide block. An injection mold, wherein the slide blocks are moved in a direction in which they abut or separate from each other by a locking block.