JPH02194919A - Manufacture of resin product equipped with insert - Google Patents

Abstract

PURPOSE:To prevent excess resin material from creeping round by a method wherein a cap part, which prevents resin material from creeping round unnecessarily, in integrally formed in advance to an insert such as a reinforcing ring or the like and further a recessed step part to enhance sealing force and a space to accumulate leaked material are provided in the insert. CONSTITUTION:A reinforcing ring 2, to which a cap part 5 is integrally formed, is fitted to a columnar projected part 13, which is projectingly provided to one split mold 12, at its end on material pouring-in side. Poured resin material fills through a gate 11 to a cavity 9 without being gone round to the inside of the reinforcing ring 2. The resin material filled to the gate 11 adheres to the outside of the cap part 5 so as to be cut off and removed together with the cap part 5 at the finishing process after molding. Further, an annular recessed step part 6 is formed in advance at the inner periphery of the other end of the reinforcing ring 2 so as to provide an annular space 7 between the reinforcing ring 2 and the split mold 12 in order to prevent resin material from leaking through a pressure-welded part to an inner diameter side at pressure molding. Further, when material leaks through the pressure-welded sealing part by any chance, the material is accumulated in the space 7, resulting in allowing to prevent the material from creeping round to the inner diameter side of the reinforcing ring 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a molding technology for resin products, and particularly to a method for manufacturing a resin product including an insert product.

[Conventional technology]

Conventionally, an example of this type of resin product has a ring-shaped resin molded part (1), as shown in FIG.

Gear products are known in which a metal reinforcing ring (2) is attached concentrically and integrally to the inner periphery of this resin molded part (1).

The above gear product is molded by injection molding using a mold (8) as shown in Fig. 3, and the cavity (9) of this mold (8), which is a combination of a plurality of split molds,
The reinforcing ring (2) is positioned and arranged in advance in the cavity (2) from the sprue (10) through the gate (11).
9), and wait for the material to harden to integrate the resin molded part (1) made of the material with the reinforcing ring (2).The split mold (12) that supports the reinforcing ring (2) is ) is formed with a columnar protrusion (13) that fits into the shaft hole (3) of the reinforcing ring (2), and by fitting both together, the reinforcing ring (2)
). After the mold is opened, the product is removed from the mold (8) using a plurality of extrusion rods (not shown), and the product is removed from the mold (8) using a plurality of extrusion rods (not shown). Since the resin (4, shown by the chain line in FIG. 2) filled in the gate (11) is attached in a hardened state, the resin (4) is cut and removed in the subsequent finishing process (gate cut). .

[Problem to be solved by the invention]

In the above manufacturing method, when a resin material is injected into the cavity (9), a part of the material enters between the shaft hole (3) of the reinforcing ring (2) and the protrusion (13) of the split mold (12). shaft hole (3
), which may cause a defect in the appearance of the product or cause functional problems if the resin that has spread inside the product peels off when the product is used. In addition, some products have strict specifications regarding the surface roughness of the reinforcing ring (2), which requires finishing work to remove the resin that has gone inside the shaft hole (3), and may damage the inner diameter surface during this work. This may result in a dimensional error that exceeds the tolerance. In response to these problems, the prior art has been limited to strictly limiting the dimensions of the shaft hole (3) and the protrusion (I3), and no fundamental solution has yet been found.

[Means to solve the problem]

In view of the above points, the present invention provides a method for manufacturing a resin product equipped with an insert that prevents the resin material from going around excessively. In the method of positioning and arranging an insert product exhibiting a substantially cylindrical shape, waiting for the hardening of the resin material filled in the cavity, and then integrally attaching the insert product to the inner periphery of a resin molded part, the resin material injection side of the insert product A lid part that prevents the resin material from going around locally is preliminarily molded on one end of the lid, and a four-step part is preliminarily formed on the inner periphery of the other end which is pressed against the mold by the injection pressure of the resin material applied to the lid part. A space is set between the insert and the mold, and after molding, the lid is cut and removed together with the resin attached to the outside thereof.

[For production]

When attaching a substantially cylindrical insert to the inner periphery of a resin molded part as described in l, when injecting resin material into the cavity, the material may go around from both ends of the insert toward the inner diameter. Care must be taken to ensure that this is not the case. The present invention has been devised to solve this problem, and first, for the end on the material injection side, a lid part that closes the end opening is integrally molded in advance to prevent the material from going around. In finishing work after molding, the lid part is cut and removed together with the resin attached to the outside thereof. As the material is injected, a large pressure is applied to the lid, and the insert is pushed toward the other end that does not have the lid, pressing the other end against the mold.

The present invention makes effective use of this material injection pressure for the other end of the insert, and for this purpose, a recessed step is formed in advance on the inner periphery of the end to create a space between the insert and the mold. Set. The end portion formed with the recessed step portion reduces its end area, increases the contact pressure per unit area with respect to the mold, and improves the sealing force of the portion. Furthermore, in the event that some material leaks through the pressure seal, the material is stored in the space to prevent it from entering the inner diameter of the insert.

〔Example〕

Next, embodiments of the present invention will be described in accordance with the case where the above-mentioned gear products are manufactured.

Figure 1 shows the mold (8) used to manufacture the gear product.
The position of (+1) has been slightly changed in conjunction with molding the lid part (5) on the reinforcing ring (2) compared to the mold (8) of the prior art described above. Become.

- A reinforcing ring (2) with a cover (5) integrally molded on the end of the material injection side on the columnar protrusion (13) protruding from the split mold (12).
) fit together. As a result, the resin material injected from the sprue (lO) does not go around the inner side of the reinforcing ring (2) from the one end side, but flows from the gage (11) to the cavity (3).
The resin material filled in (+1) adheres to the outside of the lid (5) (on the right side in the figure), and in the finishing process after molding, the lid (5) is removed from this adhered resin (4). (cut along the broken line in Figure 541). In addition, an annular concave step (8) is formed in advance on the inner periphery of the other end of the reinforcing ring (2).
is formed, and an annular space (7) 6 is set between the reinforcing ring (2) and the split mold (12).

During material injection, the reinforcing ring (2) receives a large material injection pressure from the lid (5), and is strongly pressed to the left as a whole, and the other end is pressed against the split mold (12) with a large contact pressure. Accordingly, leakage of the resin material from the press-contact portion to the inner diameter side is prevented. In addition, in the event that there is any material leaking from the pressure seal, the material is stored in the space (7), thereby preventing the material from going around to the inner diameter side of the reinforcing ring (2). In order to ensure that the other end is pressed against the one-piece mold (12), the dimensions are set so that n>12. 1. The difference between and the sentence is 0.1~ in actual size! ■That,
It is sufficient.

〔Effect of the invention〕

As explained above, the manufacturing method of the present invention includes integrally molding in advance a lid portion that prevents unnecessary penetration of the resin material onto the insert product such as the reinforcing ring.

In addition, a concave step that increases the sealing force and a space to store leaked material are set, and the lid is cut and removed together with the resin attached to the outside in the finishing process after molding. Since the resin does not go around inside, it prevents problems such as poor product appearance and malfunction due to peeling of the resin, and the process of removing the resin can be omitted, and the insert product will not be damaged.
Furthermore, since it becomes possible to obtain rough dimensional accuracy of the mold and the insert, manufacturing costs can be reduced accordingly.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a main part showing an example of a mold used to carry out the method of the present invention, Fig. 2 is a cross-sectional view of a gear showing an example of a resin product equipped with an insert, and Fig. 3 is a conventional molding. It is a half-cut sectional view showing a mold. (1) Resin molded part (2) Reinforcement ring (3) Shaft hole (4
) Resin (5) Lid (6) Recessed step (7) Space
(8) Molding mold (9) Cavity (10) Sprue
(11) Gate (12) Split type (13) Projection

Claims (1)

[Claims] 1. Position and arrange the approximately cylindrical insert (2) in the cavity (9) of the mold (8), wait for the resin material filled in the cavity (9) to harden, and then insert the resin molded part (1). In the method of integrally attaching the insert product (2) to the inner periphery of the insert product, a lid portion (5) is provided at the end of the resin material injection side of the insert product (2) to prevent local penetration of the resin material in advance. is integrally molded, and the lid part (5)
A recessed step (6) is formed in advance on the inner periphery of the other end that is pressed against the mold (8) by the injection pressure of the resin material applied to the insert (2) and the mold (8) to create a space ( 7), and after molding, the lid part (5) is cut and removed together with the resin (4) attached to the outside thereof.