JPS6169410A - Molding die - Google Patents

Abstract

PURPOSE:To produce no flash and consequently eliminate deflashing and at the same time enable to design a motor with high accuracy by a method wherein a tubular elastically deformable shell body is fitted in a fitting groove formed onto the outer peripheral surface of a core and a hydraulic circuit to communicate with the fitting groove is formed in the core. CONSTITUTION:A tubular elastically deformable shell body 4 is fitted in a fitting groove 3 formed onto the outer peripheral surface of a core 1 and made freely expandable by being applied with hydraulic pressure through a hydraulic circuit formed in the core 1 so as to communicate with the fitting groove 3. When the fitting of an insert 2 onto the core 1 and removal of a molded part from the core 1 are intended, no hydraulic pressure is applied to the shell body 4, resulting in forming clearance between the outer peripheral surface of the core 1 so as to facilitate said fitting and removal. When the molding is intended, hydraulic pressure is applied to the shell body 4 so as to deform the shell body 4 elastically in order to eliminate the clearance between the outer peripheral surface of the core 1 and the inner peripheral surface of the insert by expanding the shell body 4, resulting in enabling to eliminate the production of flash.

Description

[Detailed description of the invention] [Technical field 1 The present invention relates to a mold for insert molding.

[Background Art] In conventional molds used for insert molding that hold the inner peripheral surface of the insert on the outer peripheral surface of the mold shaft, a fitting groove is formed on the outer peripheral surface of the mold shaft, and the inner peripheral surface of the insert is held on the outer peripheral surface of the mold shaft. The insert was made easier to fit into the mold shaft by creating a clearance between the insert and the mold shaft, but this clearance caused burrs, which not only required burr finishing, but also made it difficult to fit the insert into the mold shaft. There was a problem that the accuracy of center deviation of the mold axis was poor, making it impossible to design high-precision motors and other parts.

[Objective of the Invention J The present invention was made in light of the above circumstances, and its purpose is to facilitate the fitting of the insert to the mold shaft, but to prevent the molded product from forming after molding. can be easily removed and
In addition to being able to pull out the mold, there is no need for burrs, which eliminates the need for burr finishing as in the past.Furthermore, the accuracy of center misalignment between the insert and the mold axis can be significantly improved, making it possible to design highly accurate motors. The object of the present invention is to provide a mold for insert molding.

[Disclosure of the Invention J The molding die of the present invention has an insert 2 on the outer peripheral surface of the mold shaft 1.
This is a mold used for insert molding that holds an inner peripheral surface, and an elastically deformable cylindrical shell body 4 is fitted into a fitting groove 3 formed on the outer peripheral surface of a mold shaft 1. 1 and fitting groove 3
A hydraulic circuit 5 is formed in communication with the shell body 4 by hydraulic pressure.
This configuration allows the above object to be achieved. That is, by not applying hydraulic pressure to the shell body 4 when fitting the insert 2 to the mold shaft 1 and when taking out the molded product from the mold shaft 1, the relationship between the outer peripheral surface of the mold shaft 1 and the inner peripheral surface of the insert 2 is maintained. A clearance is formed between them to facilitate fitting and removal, and during molding, the shell body 4 is elastically deformed and expanded by applying hydraulic pressure. :! (1) It is possible to eliminate the clearance between the outer circumferential surface and the inner circumferential surface of the insert, thereby eliminating the occurrence of cracks.

The present invention will be described below based on embodiments shown in the accompanying drawings. A core 7 is fitted into the upper mold 6, and a mold shaft 1 is fitted into the lower mold 8. When the upper mold 6 and the lower mold 8 are closed, the lower surface of the core 7 and the mold shaft 1 are fitted. A fitting groove 3 is formed over the entire circumference of the upper outer peripheral surface of the mold shaft 1, which is pressed against the upper surface of the mold shaft 1 to form a donut-shaped cavity 9. The fitting groove 3 consists of an inner groove 3a with a small vertical width and an outer groove 3b with a large vertical width that is continuous with the inner groove 3a via a step, and a cylindrical shell body 4 is fitted into the outer groove 3b. . The shell body 4 is like a thin metal cylinder that can be elastically deformed to expand and contract. A hydraulic circuit 5 connected to a hydraulic pump is formed on the mold shaft 1, and this hydraulic circuit 5 is communicated with the inner groove 3a of the fitting groove 3 so that the shell body 4 can be freely expanded by hydraulic pressure. To perform insert molding with the mold A constructed in this way,
With no hydraulic pressure applied to the shell body 4, a motor coil 11, which is wound as an insert 2 around an iron core 10 with an inner diameter r equal to the diameter R of the mold shaft, is fitted to the mold shaft 1 of the lower mold 8. 113
The inner circumferential surface of the insert 2 is held on the outer circumferential surface of the mold shaft.

In this case, the fitting groove 3 connects the inner peripheral surface of the iron core 10 with the mold shaft 1.
Since there is a clearance between the outer peripheral surface of the connector and the outer peripheral surface of the connector, the fitting operation is facilitated. Next, close the upper mold 6 and insert flf into the cavity 9.
The shell body 4 is filled with oil 12, heated in this state, and hydraulic pressure is applied to the L body 4 via the hydraulic circuit 5 by a hydraulic pump to expand the shell body 4, and its outer circumferential surface is pressed against the inner circumferential surface of the iron Hxo. . Therefore, the clearance between the outer circumferential surface of the mold shaft l and the inner circumferential surface of the insert 2, that is, the inner circumferential surface of the iron core 10, is eliminated, so that there is no occurrence of paris, and the shell body 4 is Since the outer circumferential surface is pressed against the inner circumferential surface of the iron core 10, the accuracy of center deviation between the insert 2 and the mold shaft 1 is significantly improved.For example, in the conventional case, the runout accuracy was 0.05.
This improved from 0.005 to 0.005. After this upper mold 6
, remove the hydraulic pressure, return the shell body 4 to its original state, and take out the molded product. In this case, the iron core 10 is
Since a clearance is formed between the inner peripheral surface of the mold shaft 1 and the outer peripheral surface of the mold shaft 1, the molded product can be easily removed.

[Effect of the invention 1 In the present invention, an elastically deformable cylindrical shell body is fitted into a fitting groove formed on the outer circumferential surface of a mold shaft, and communicates with the fitting groove on the mold shaft. A hydraulic circuit is formed to allow the shell body to expand freely using hydraulic pressure, so no hydraulic pressure is applied to the shell body during insert molding! ! By fitting the insert into the fitting groove of the mold shaft with l, a clearance is created between the inner circumferential surface of the insert and the outer circumferential surface of the mold shaft, making the fitting work easier, and During molding, hydraulic pressure is applied to the shell body via a hydraulic circuit to cause the shell body to elastically deform and expand, and its outer circumferential surface is pressed against the inner circumferential surface of the insert, so that the outer circumferential surface of the mold shaft and the inner circumference of the insert are This eliminates the clearance between the mold shaft and the insert surface, which eliminates the need for deburring as in the past, and eliminates the need for deburring. Because they are in pressure contact, the accuracy of center misalignment between the insert and the mold axis is significantly improved, making it possible to create highly accurate morph designs. After returning to the original state, the molded product can be removed with the fitting groove forming a clearance between the inner circumferential surface of the insert and the outer circumferential surface of the mold shaft, and the molded product can be easily taken out. It is something.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing insert molding according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the mold axis in the same as above, where A is a molding die, 1 is a mold axis, and 2 is an insert. ,3
4 is a fitting groove, 4 is a shell body, and 5 is a hydraulic circuit. Agent Patent Attorney Ishi 1) Chief 7 1 Figure 2

Claims (1)

[Claims] (1) A mold used for insert molding that holds the inner peripheral surface of the insert on the outer peripheral surface of the mold shaft, and is a cylindrical shell body that can be elastically deformed into a fitting groove formed on the outer peripheral surface of the mold shaft. What is claimed is: 1. A molding die, in which a hydraulic circuit is formed in the mold shaft to communicate with the fitting groove, and the shell body is expandable by hydraulic pressure.