JPS6341137Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an insert for injection molded products.

Conventional inserts 1 and 11 of this type include those placed inside a molded product body 2 made of plastic material as shown in FIG. 1, and those placed at one end of the molded product body 12 as shown in FIG. Those placed on the outside are known. The former insert 1 is tightened by the contraction of the molded product main body 2 after molding, and a part of the main body 2 is buried in knurling formed on the outer peripheral surface thereof during molding, so that it is firmly integrated with the main body 2. However, since the latter insert 11 is arranged in the opposite manner to the former, it has the disadvantage that when the molded product main body 12 contracts, a gap is created between the molded product body 12 and the molded product main body 12, making it impossible to maintain the integral fixation. This is especially true when the insert 11 is made of a metal material, since the shrinkage rate of the molded body 12 of plastic material is greater than this.

This idea is for injection-molded products such as the latter type, in which the insert and the main body can be kept integrally fixed even if the molded product body shrinks by performing simple processing on the shape of the insert. The purpose is to provide inserts.

The above object is achieved by forming the inner surface of the insert into a tapered surface whose diameter gradually decreases toward the other end of the main body.

Examples of this invention will be described below.

In FIG. 3, reference numeral 21 denotes a hollow cylindrical insert, and the inside of this insert 21 is filled with one end portion of a molded product main body 22 made of a plastic material. The inner surface of the insert 21 is formed into a tapered surface 23 whose diameter gradually decreases toward the other end of the main body 22, as shown in FIGS.
At the end of the insert 21 on the expansion side of 3,
A pair of locking engagement grooves 24, 24 are formed facing each other along the axial direction.

In the above-mentioned product, when the main body 22 contracts after molding as shown by the arrow in FIG.
As shown in the enlarged view, the length and inner diameter of the insert 21 create an axial force a and a radial force b, so the force c acting on the tapered surface 23 of the insert 21 of the main body 22 due to both forces a and b is tapered surface 2
It acts like a wedge in the direction opposite to 3. Therefore, the insert 21 and the main body 22 are fixedly integrated without creating a gap between them. Furthermore, since a portion of the main body 22 is buried in the engagement grooves 24, 24, relative rotation between the insert 21 and the main body 22 is prevented.

In the above embodiment, the insert 21 is described as having a cylindrical shape, but this is merely an example, and other suitable cylindrical shapes may also be used. This can be omitted by notching a screw or the like.

This idea is as described above, and even if the molded product body contracts after molding, the force acting on the tapered surface of the insert of the body due to this contraction will act in a direction opposite to the tapered surface. There is no gap between the insert and the main body, which has the excellent effect of reliably maintaining the insert and the main body integrally.

[Brief explanation of the drawing]

Figures 1 and 2 are a longitudinal sectional front view showing an injection molded product including a conventional insert, Fig. 3 is a longitudinal sectional front view showing an embodiment of this invention, Fig. 4 is an enlarged sectional view of the same insert, and Fig. 5. is a sectional view taken along the - line in FIG. 4, and FIG. 6 is an explanatory diagram of the operation. 21...insert, 22...molded product body, 2
3... Tapered surface, 24, 24... Engagement groove.

Claims (1)

[Scope of utility model registration request] An insert for an injection molded product whose inside is filled with one end of a molded product main body made of plastic material, characterized in that the inner surface of the insert is formed into a tapered surface whose diameter gradually decreases toward the other end of the main body. Inserts for injection molded products.