JPH0422978Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention forms a locking part on a metal member, and uses this locking part to integrally attach the metal member to a synthetic resin body. This invention relates to an insert mold for molding in a state.

[Prior Art] Conventionally, as a manufacturing method for molding a synthetic resin reel with a metal member integrally attached to a part, first, a boss for adhesion is integrally formed in a part of the reel. A reel body made of synthetic resin is formed by injection molding, and the boss and a locking hole formed in a metal member are integrated by welding in a subsequent process. According to this conventional manufacturing method, it has been pointed out that there are problems in that the yield decreases due to variations in dimensional accuracy during the welding process, scratches on the product, etc., and the unit price of the product increases.

In order to solve this problem, a manufacturing method using insert molding has been proposed. According to this manufacturing method, a metal member having a locking hole is installed in advance in the cavity part of an insert molding die,
By pouring molten resin into this cavity, the synthetic resin and the metal member are integrated at the locking hole. For the above-mentioned insert molding, an insert molding fixing method has been proposed, for example, as in JP-A-55-148141.

[Problems to be solved by the invention] In such a conventional manufacturing method using an insert mold, the reel main body and the metal member formed of synthetic resin are separated from each other after being released from the mold. As they cool, post-deformation occurs due to the difference in their thermal contraction rates. For this reason, it becomes extremely difficult to ensure the dimensional accuracy of the joint surfaces of the metal member and the reel body with respect to the reference plane of the formed product. As a result, when the surface of a metal member is attracted by a magnet or the like and rotated,
This will cause problems such as face-to-face contact.

This idea was created in view of the above-mentioned problems, and the purpose of this idea is that when insert molding a metal member into a part of a synthetic resin member, after the mold is released from the mold, To provide an insert molding die which can ensure molding accuracy by eliminating post-deformation caused by the difference in coefficient of thermal expansion of materials during cooling, and which does not impair external appearance.

"Means for Solving the Problems" In order to solve the above-mentioned problems and achieve the objectives, the insert molding die of the present invention has the following configuration. That is, molten resin is injected into a cavity formed by a fixed mold and a movable mold, and the above-mentioned method is also applied to the inside of a metal member in which a locking hole is formed in a part thereof. An insert forming mold for molding an integrally constituted molded product by injecting molten resin, the movable mold has a fixed mold and a movable mold connected to each other, and the metal A lightening pin is attached that occupies a portion of the locking hole of the member and is inserted in a buried state.

[Function] In the insert molding die configured as described above, after molding, the resin filled in the locking hole is filled with a hole defined by the lightening pin, taking into account the thermal contraction of the molten resin. A space has been created where In this way, even if this molten resin heat-shrinks due to cooling and solidification after being released from the mold, this heat shrinkage is absorbed by the aforementioned space, and the metal member is eventually flattened without deformation. It is integrally attached to the resin part while maintaining good surface accuracy.

[Example] Below, the configuration of an example of the insert molding die according to the invention will be described in detail with reference to the accompanying drawings.

First, as shown in FIG. 1, a molded product 12 molded by this insert molding die 10 includes a main body 12a made of synthetic resin and a substantially circular plate shape;
The metal member 12b is coaxially and integrally attached to the lower surface of the metal member 12a. The metal member 12b is formed of, for example, SUS in an annular shape, and locking holes 12c are formed at predetermined intervals. Each locking hole 12c is formed from a large diameter portion 12c ₁ located on the lower surface side and a small diameter portion 12c ₂ located on the upper surface side in communication with the large diameter portion 12c 1 .

The metal member 12b formed in this way is inserted into the cavity 14 of the insert molding die 10, which will be described later.
By attaching the resin to the main body 12a, the molten resin filled in the cavity 14 and defining the main body 12a flows into each locking hole 12c, cools and solidifies, and is integrally attached to the main body 12a. has been done.

Next, with reference to FIGS. 2 and 3, the configuration of the insert molding die 10 for integrally molding the above-described molded product 12 will be described in detail.

FIG. 2 shows an insert mold 1 of an embodiment.
0 is shown, but this insert mold 1
0 has a substantially vertically symmetrical structure with respect to the central axis, so
Only the upper half is shown, and the lower half is omitted.

This insert molding mold 10 has a fixed mold 16
The movable mold 18 is provided to be movable toward and away from the fixed mold 16 along the axial direction, and the ejector member 20 is slidably attached to the movable mold 18. ing.

This fixed mold 16 includes a fixed side mounting plate 22 that is attached to a mounting portion (not shown), and a fixed side mold plate 24 that is fixed to this fixed side mounting plate 22 and defines one surface of the cavity 14. . A spool member 26 in which a spool 26a is formed is attached to the fixed side mounting plate 22 and the fixed side template plate 24 through their central portions.

The movable mold 18 includes a movable mounting plate 28, a receiving plate 32 that is attached to the movable mounting plate 28 at a distance via a plurality of spacer blocks 30, and a fixed metal plate that is fixed to the receiving plate 32. It is provided with a movable side mold plate 34 that is in close contact with a fixed side mold plate 24 of the mold 16. A recess 36 defining the other surface of the cavity 14 is formed in the surface of the movable mold plate 34 that faces the fixed mold plate 24 . Furthermore, a runner 38 and a gate 40 are formed on the above-mentioned surface of the movable mold plate 34 to allow the cavity 14 and the spool 26a to communicate with each other. The movable mold 18 is capable of reciprocating along the axial direction by a drive cylinder (not shown).

The ejector member 20 described above is attached to the movable mold 18
Two ejector pins 42a are provided so as to be movable along the axial direction between the movable side mounting plate 28 and the receiving plate 32, and are arranged to penetrate through the receiving plate 32 and the movable side mold plate 34. , 42b are integrally provided in parallel with each other in a state of extending along the axial direction.
Note that one ejector pin 42a is connected to the cavity 1.
A plurality of ejector pins 42b are disposed along the outer circumference of the cavity 14 in order to release the solidified synthetic resin, that is, the molded product, from the mold.
In order to take out the synthetic resin remaining and solidified in the spool 26a, one is provided corresponding to the center portion of the cavity 14.

This ejector member 20 is biased by a coil spring (not shown) so as to come into pressure contact with the movable side mounting plate 28. In this pressed state, the distal end surface of one ejector pin 42a constitutes one side portion of the cavity 14, and the distal end surface of the other ejector pin 42b constitutes the bottom surface of the runner 38. The ejector member 20 is moved around the movable mold 1 by the elastic force of the coil spring.
8, which will be described later, moves partway along with the movable mold 18, and after it comes into contact with a protruding rod (not shown) fixed to the molding machine, it is stopped and the coil is removed. It is configured to move rightward in the figure relative to the movable mold 18 while compressing the spring.

Further, the shape of the cavity 14 described above is
It is formed to define the external shape of the molded product shown in the figure. Here, in the insert molding die 10 according to this embodiment, a metal member 12b as an insert body is installed in advance at a predetermined position within the cavity 14. The mounting position of the metal member 12b is set coaxially with the lower surface of the synthetic resin main body 12a, as already shown as the molded product 12 in FIG. In this insert molding die 10, a metal member 12b is attached to the fixed side template 24 in order to achieve this mounting position.

More specifically, as shown in FIG.
In a state in which the fixed side templates 24 of No. 6 are joined to each other, a lightening pin 50 is attached to be inserted into the locking hole 12c of the metal member 12b. That is,
This lightening pin 50 is shown in FIG. 4 in a state in which it extends to the interface between the small diameter portion 12c ₂ and the large diameter portion 12c ₁ of the locking hole 12c of the metal member 12b installed in the cavity 14. As shown, it is inserted through a part of the small diameter portion _12c2 . Since this lightening pin 50 is present in the small diameter portion 12c ₂ of the locking hole 12c, when injecting molten resin, the resin is transferred to the locking hole 1 except for the portion where the lightening pin 50 is provided.
2c will be filled. In other words, a lightened portion (space) is formed in the portion of the locking hole 12c where the lightened pin 50 is located upon completion of molding.

In this way, the locking hole 12 by the lightening pin 50
When the metal member 12b is integrally insert-molded into the main body 12a made of synthetic resin, the size of the hollowed out portion formed in
It is set in advance in anticipation of deformation by shrinking as it cools and solidifies. As a result, the effect of thermal contraction during cooling and solidification of the molten resin is absorbed by this hollowed out part,
Subsequent deformation of the metal member 12b will no longer occur.

Insert molding mold 1 configured as above
The operation of insert-molding the molded product 12 using 0 will be described below.

Insert molding die 10 in the state shown in FIG.
Then, the molten resin is injected via the spool member 26. The injected molten resin is brought into the cavity 14 via the spool 26a, the liner 38, and the gate 40 in this order. In this way, cavity 1
The molten resin brought into the chamber 4 will spread well to every corner. That is, this molten resin flows into the locking hole 12c of the metal member 12b that is previously installed at a predetermined position within the cavity 14, except for the portion where the aforementioned lightening pin 50 is located.

After the molten resin has been injected into the cavity 14 and the resin has cooled and solidified to some extent, the molding operation of the molded product 12 is started. This mold release operation is started by moving the movable mounting plate 28 to the left in FIG. As the movable mounting plate 28 moves, the movable mold 18 is moved to a mold separation surface defined by the contact surfaces of the movable mold plate 34 and the fixed mold plate 24 of the fixed mold 16. The molded product 12 is separated from the fixed mold 16 with L as the border.
is stuck to the movable mold 18 and moves to the left side in the figure together with the movable mold 18.

Incidentally, as the movable mold 18 moves, the tip of the lightening pin 50 aligns with the locking hole 1 of the metal member 12b.
It will be extracted from within 2c. The locking hole 12 after the lightening pin 50 is pulled out.
In the resin filled in c, a space is formed as a hollow pin portion.

On the other hand, as mentioned above, the ejector member 20 will once move to the left in the figure together with the movable mold 18 due to the biasing force of the coil spring, but this movement is prevented by contacting an ejector rod (not shown). It will be suspended. Therefore, the ejector pins 42a and 42b, which were integrally attached to the ejector member 20, protrude relatively from the movable mold 18 to the right in the figure. In response to the protrusion of the ejector pins 42a and 42b, the molded product 12 is pushed out of the cavity 14 and released from the mold.

Here, after the molten resin described above is released from the mold,
As the resin is cooled and solidified, post-deformation occurs due to the difference in thermal contraction rate between the resin and the metal.
However, in this embodiment, in anticipation of subsequent deformation, a space is formed in the synthetic resin filling the locking hole 12c of the metal member 12b in advance as a hollowed out portion, so that the metal member 12b is completely After the metal member 12b is cooled and solidified, the deformation will be absorbed by the hollowed out part.
will not be deformed (curved) and will be formed in a flat shape, that is, in a state where it is maintained in the shape intended in the design as a molded product. In this way, the metal member 12 relative to the reference surface of the molded product 12
The dimensional accuracy of the joint surfaces of b and main body 12a is
Sufficient security will be provided.

In this manner, according to this embodiment, when the molded product 12 is, for example, a reel in which the metal member 12b is attracted by a magnet and rotated, surface contact etc. during this rotational drive can be avoided. There will be no problems at all. Furthermore, the above-mentioned lightened portion is not formed as a through hole, but is formed inside the molded product 12 without being exposed to the outside surface. In this way, the hollowed out portion does not impair the appearance of the molded product 12.

Furthermore, according to this embodiment, the metal member 12
The shape will maintain the previously molded shape even after insert molding. In this way, by accurately maintaining the surface precision of the metal member 12 formed in advance, the effect of achieving good surface precision of the metal member 12 after molding can be achieved.

It goes without saying that this invention is not limited to the configuration of the one embodiment described above, and can be modified in various ways without departing from the gist of this invention.

For example, in the embodiment described above, the main body 12a made of synthetic resin is positioned so as to cover the outer peripheral portion of the metal member 12b. In order to prevent such slight deformation of the metal member 12b due to thermal contraction of the covered resin portion, a configuration as shown in FIG. 5 as a modification of the embodiment may be used.

That is, as shown in FIG. 5, in this modification, a chamfered portion 52 is formed on the outer peripheral portion of the metal member 12b facing the cavity 14. Since this chamfered portion 52 is formed, thermal contraction of the synthetic resin is absorbed by sliding along this chamfered portion. In this way, although a sufficient initial effect is achieved in the one embodiment described above, according to this variant,
Furthermore, post-deformation due to heat shrinkage is reliably eliminated.

[Effects of the invention] As detailed above, the insert molding mold according to this invention injects molten resin into the cavity formed by the fixed mold and the movable mold,
In a plastic mold for molding a molded product integrally equipped with a metal member partially formed with a locking hole, the movable mold has a fixed mold and a movable mold joined to each other. , a lightening pin inserted into a portion of the locking hole of the metal member is attached.

Therefore, according to this invention, when insert molding a metal member into a part of a synthetic resin member,
We provide an insert molding mold that can ensure molding accuracy by eliminating post-deformation that occurs due to the difference in thermal expansion coefficients of each material as it cools down after being released from the molding mold, and that does not impair the appearance. can do.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a molded body formed by an embodiment of the insert molding die according to this invention, and FIG. 2 is a cross-sectional view of the insert molding die for molding the molded body shown in FIG. 1. A half-sectional view showing the configuration,
Fig. 3 is an enlarged half-sectional view showing the state in which the metal member is installed in the cavity, Fig. 4 is a side view showing the locking hole with the lightening pin inserted, and Fig. 5 is a side view showing the locking hole with the lightening pin inserted. FIG. 7 is a half-sectional view showing a modification of the configuration of the embodiment. In the figure, 10...insert mold, 12...
Molded product, 12a... Main body, 12b... Metal member, 12c... Locking hole, 12c ₁ ... Large diameter part, 12
c ₂ ... small diameter part, 14 ... cavity, 16 ... fixed mold, 18 ... movable mold, 20 ... ejector member, 22 ... fixed side mounting plate, 24 ... fixed side mold plate, 24a ... Mounting surface, 26 ... Spool member, 26a ... Spool, 28 ... Movable side mounting plate, 30 ... Spacer block, 32 ... Reception plate,
34... Movable side template, 36... Recess, 38... Runner, 40... Gate, 42a, 42b... Ejector pin, 50... Lightening pin, 52... Chamfered portion.

Claims (1)

[Claims for Utility Model Registration] (1) A metal member in which a locking hole is formed in a part by injecting molten resin into a cavity formed by a fixed mold and a movable mold. An insert forming mold for molding an integrally constituted molded product by injecting the molten resin also into the locking hole, the movable mold includes a fixed mold and a movable mold. An insert molding die characterized in that a lightening pin is attached that occupies a part of the locking hole of the metal member and is inserted in a buried state when the metal members are joined together. (2) The insert molding die according to claim 1, wherein the tip of the lightening pin is located in the locking hole in the buried state. (3) The insert molding die according to claim 1 or 2, wherein an inclined surface is formed on a side edge of the metal member facing the cavity.