JPH0723222Y2 - Molding mold - Google Patents

Description

TECHNICAL FIELD The present invention relates to a molding die suitable for molding a synthetic resin in a state where a plurality of parts are combined.

2. Description of the Related Art Conventionally, a plurality of metal parts may be combined and molded of synthetic resin so as to cover the periphery thereof. As an example, FIGS. 3 and 4 show a case 1 made of metal having an outer tubular portion 2 and an inner tubular portion 3 and a tubular portion 5 fitted into the inner tubular portion 3, and Three parts, which are a metal cap 4 covering the upper end opening and a substantially cylindrical coil 6 housed in a space formed between both ends, are combined with each other, and a synthetic resin 7 is covered so as to cover the periphery thereof. An example of forming an electromagnet by molding is shown.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, if a plurality of parts are simply combined as described above and set in a molding die, and plasticized resin is injected around the molding die, for example, the cap 4 is injected by the injection pressure of the resin. May be lifted up, and the product may be molded as it is, resulting in a defective product. That is, the defect occurrence rate becomes extremely high.

Therefore, it is necessary to temporarily fix the plurality of combined parts together by welding, bonding, or the like. In the above example,
As shown in FIG. 4, the case 1 and the cap 4 are welded together at a portion indicated by the reference numeral 8 and are integrally connected. Therefore, there is a drawback that the number of working steps is increased accordingly.

SUMMARY OF THE INVENTION Therefore, according to the present invention, a plurality of parts are pressed against each other in a molding die to hold the assembled state. That is, the mold forming die according to the present invention combines a plurality of parts configured to hold the assembled state by pressing from one direction, and molds the synthetic resin so as to cover the periphery thereof. In the molding die of the above item, a work pressing member that can project into the cavity along the above direction is provided so as to maintain the assembled state of the above parts, and the work pressing member is a spring member having a biasing force corresponding to the injection pressure. It is characterized in that it is biased in the protruding direction.

Action The work holding member projects into the cavity and presses the plurality of metal parts against each other, whereby the assembled state is maintained. That is, when the plasticized resin is injected, lifting of each component is prevented. Then, when the resin finally spreads into the cavity and the resin pressure further rises, the work pressing member retracts and is molded into a desired shape.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

This embodiment shows a molding die used for molding an electromagnet, which is composed of three parts of the case 1, the cap 4 and the coil 6 as in the conventional example described above.

This molding die is a lower die 11 on which the case 1 and the like are placed.
And an upper die 12 having a substantially cylindrical cavity 13, and a guide hole is provided at the center of the top surface of the cavity 13 of the upper die 12.
14 is recessed. A work holding member 15 is slidably fitted in the guide hole 14, and the work holding member 15 is biased by a coil spring 16 in the protruding direction. The biasing force of the coil spring 16 is appropriately set according to the injection pressure of the resin injected into the cavity 13. Further, the tip surface of the work holding member 15
The reference numeral 15a forms a part of the mold surface, and is formed in a flat surface in this embodiment corresponding to a desired shape of the molded product. The movable range of the work holding member 15 is regulated to a fixed range by a stopper (not shown) so that the tip surface 15a of the work holding member 15 is aligned with the surrounding mold surface when the work holding member 15 retracts.

In the molding using the molding die described above, it is not necessary to temporarily fix the respective parts including the case 1, the cap 4 and the coil 6 by welding or the like, and it is sufficient to simply set them in a combined state. Then, when the upper die 12 is clamped, as shown in FIG. 1, the work holding member 15 presses the cap 4 and presses the three parts in the vertical direction, so that the assembled state of each part is maintained. It

Therefore, when the plasticized resin is injected through the runner (not shown), the cap 4 is prevented from rising. In particular, if it is possible to prevent the cap 4 from floating at the moment when the resin flows into the cavity 13, then the resin that has flowed over the cap 4 tries to press the cap 4 toward the case 1 side. Is reliably maintained.

When the resin fills the cavity 13,
Since the resin pressure inside 13 rises sharply, the coil spring
The work holding member 15 retracts against the urging force of 16
As shown in the figure, the tip surface 15a is in a state of being matched with the surrounding mold surface.

Therefore, the molded product taken out after curing has a flat top surface and has a desired shape, and no hole for holding the work remains.

EFFECTS OF THE INVENTION As is clear from the above description, according to the molding die of the present invention, resin molding can be performed while maintaining a state in which a plurality of metal parts are combined with each other. Separation and floating of the are reliably prevented.
Therefore, a temporary fixing process such as welding as in the past is not necessary, and the process can be simplified and streamlined.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a molding die according to the present invention, FIG. 2 is a sectional view showing a state where resin is injected into the cavity, and FIG. 3 is an example of a metal part to be molded. FIG. 4 is an exploded cross-sectional view showing the molded product. 11 …… Lower mold, 12 …… Upper mold, 15 …… Work holding member, 16
……coil spring.

Claims (1)

[Scope of utility model registration request] 1. A mold forming die for combining a plurality of parts configured to hold an assembled state by pressing from one direction and molding a synthetic resin so as to cover the periphery thereof, A work pressing member that can project into the cavity along the above direction is provided so as to maintain the assembled state of the above parts, and the work pressing member is biased in the projecting direction by a spring member having a biasing force corresponding to the injection pressure. A mold forming die characterized in that.