JPH0595714U - Mold - Google Patents

Abstract

(57) [Abstract] [Purpose] A plurality of split molds 1, 2 and 3 defining a cavity 4 and a burr groove 5 at the time of mold clamping are provided, an insert part b is placed in the cavity 4, and a molding material is formed in the cavity 4. With respect to a molding die for molding a molded product that is filled with d and integrally has the insert part b, the variation in the filling amount of the molding material d is absorbed, and when the filling amount is too large, the insert part b does not apply pressure such as resin. Even if it is easily received and dented, excess molding material d is prevented from denting the insert part b and overflowing to the outside. A gap 9 for communicating the cavity 4 and the burr groove 5 with each other is provided between the predetermined split molds 1 and 2, and when the filling amount of the molding material d is too large, the excess molding material d is It is guided to the burr groove 5 through the gap 9.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a molding die related to molding technology.

[0002]

[Prior Art]

 In the case of transfer molding the molded product a shown in FIG. 3, conventionally, the molding die shown in FIG. 4 has been used. The molded product a in FIG. 3 is obtained by vulcanizing and adhering a ring-shaped lip-like rubber c to the resin-made insert part b having a ring shape. The mold shown in FIG. 4 has a plurality of split molds defining a ring-shaped cavity 4 and a ring-shaped burr groove 5 located on the outer peripheral side thereof when the mold is clamped, that is, a lower mold 1, an upper mold 2 and a middle mold 3. Further, a plunger 6 is combined with the upper mold 2 and the middle mold 3 which function as a pot, and a sprue 7 is provided on the middle mold 3.

The molding procedure is as follows. In the mold open state, the insert part b is fixedly engaged with the lower mold 1. The upper mold 2 and the middle mold 3 are set in the lower mold 1 and the mold is clamped. The molding material (rubber material) d is set inside the pot. The cavity 6 is filled with the molding material d by lowering the plunger 6 with a predetermined pressure. The molding material d is cured to complete the vulcanization.

[0004]

[Problems to be solved by the device]

 The above conventional technique has the following problems. That is, in this type of molding, generally, the cavity 4 is filled with a large amount of the molding material d in order to increase the internal pressure of the cavity 4, but it is difficult to appropriately control the filling amount. When the filling amount is too large, the excess molding material d dents a part of the resin insert part b and overflows to the outside to form a burr directly attached to the insert part b. In FIG. 4, a part of the insert part b (upper upper surface in the figure) is dented in this way, and a gap 8 is formed between the insert part b and the middle mold 3 which should be closely contacted with each other, and an extra molding material d is introduced from the gap 8. Shows the state of overflowing.

In view of the above points, the present invention absorbs the variation in the filling amount of the molding material d, and when the filling amount is too large, the insert part b is likely to be dented due to the pressure of resin or the like. It is an object of the present invention to provide a mold in which the excess molding material d does not dent the insert part b and overflow to the outside.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the mold of the present invention has a plurality of split molds that define a cavity and a burr groove when the mold is clamped, an insert part is placed in the cavity, and the cavity is filled with a molding material. In a molding die for molding a molded product integrally having the insert component, a gap for communicating the cavity and the burr groove with each other is provided between the predetermined split dies.

[0007]

[Action]

 If a gap that connects the cavity and the burr groove is provided between the predetermined split molds, when the filling amount of molding material is too large, excess molding material is guided to the burr groove through this gap. . Therefore, it is possible to prevent the internal pressure of the cavity from becoming abnormally high, and it is possible to prevent excess molding material from denting the insert part and overflowing to the outside.

[0008]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. The molding die is for transfer molding the molded product a shown in FIG. have.

That is, as shown in FIGS. 1 and 2, a gap 9 is provided between the lower mold 1 and the upper mold 2 to connect the annular cavity 4 and the annular burr groove 5 located on the outer peripheral side thereof to each other. An annular second burr groove 10 is provided further on the outer peripheral side of the burr groove 5, and a second gap 11 that connects the burr groove 5 and the second burr groove 10 to each other is provided. The gap 9 and the second gap 11 may be annular as shown, or may be non-annular. The plurality of burr grooves 5 and 10 are provided to reduce the volume of each burr groove 5 and 10 so that the burr shape can be easily standardized.

In the molding die, when the filling amount of the molding material d is too large, excess molding material d passes through the gap 9 to the burr groove 5 from the time when the internal pressure of the cavity 4 reaches a predetermined value. When the burr groove 5 is guided and further filled with the molding material d, the molding material d is guided to the second burr groove 10 through the second gap 11. Therefore, it is possible to prevent the internal pressure of the cavity 4 from becoming abnormally high by this induction, and it is possible to prevent excess molding material d from denting the insert part b and overflowing to the outside.

The internal pressure of the cavity 4 at which the molding material d in the cavity 4 begins to flow into the burr groove 5 is determined by the viscosity of the molding material d and the size t of the gap 9. For this reason, the size t of the gap 9 may be adjusted so that the internal pressure required for molding is maintained in the cavity 4. Further, the filling amount of the molding material d may be any amount as long as the excess molding material d is not filled in both the burr groove 5 and the second burr groove 10, whereby variations in the filling amount can be absorbed. . Further, after molding, burrs are formed on the rubber c of the molded product a due to the burr groove 5 and the like, but since the burrs due to the gaps 9 are extremely thin, it is possible to finish neatly just by rubbing by hand.

Further, the present invention is effective when a large number of molding dies are prepared. In other words, if multiple molds are used, it is difficult to fill all of the cavities with the molding material in equal amounts, and there will inevitably be differences in the filling amount, causing variations in the internal pressure of the cavities. Will end up. On the other hand, according to the configuration of the present invention, excess molding material d is guided to the burr groove 5 through the gap 9 in order from the cavity whose internal pressure has reached a predetermined value.

According to the experimental data, if the variation of the filling amount is not more than 0.1 g, the molding material d deforms the insert part b to form a burr, but the filling amount is within the range of 1.25 g. Even if changed, the insert part b did not deform.

Further, the following experimental results have been obtained. Material used Rubber c: Fluorine rubber Insert part b: Resin (PPS) Vulcanization condition 180 ° C x 460 "Molding pressure 22.5 MPa (230 kgf / cm ² ) Result Insufficient injection with filling amount 1.55 g without gap 9 No burr at 1.6g, burr at 1.65g or more When gap 9 is present (gap 9 size is 0.08mm), filling amount is 1.8g, injection is insufficient, and burr is 1.85g or more. No occurrence.

[0015]

[Effect of the device]

 The present invention has the following effects. That is, since the excess of the molding material filled in the cavity is guided to the burr groove through the gap, it is possible to absorb the variation in the filling amount of the molding material, and when the filling amount is too large, Even if the insert part is easily dented by pressure of resin or the like, it is possible to prevent excess molding material from denting the insert part and overflowing to the outside. As a result, burrs attached directly to the insert parts are not formed after molding, and the troublesome finishing work of stripping the bur from the insert parts can be omitted.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a molding die according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of an essential part of the molding die.

[Fig. 3] Half-cut sectional view of a molded product

FIG. 4 is a partial cross-sectional view of a molding die according to a conventional example.

[Explanation of Codes] 1 Lower mold 2 Upper mold 3 Medium mold 4 Cavity 5 Burr groove 6 Plunger 7 Sprue 8 Gap 9 Gap 10 Second burr groove 11 Second gap a Molded product b Insert part c Rubber d Molding material

Claims (1)

[Scope of utility model registration request] 1. A plurality of split molds (1), (2) and (3) that define a cavity (4) and a burr groove (5) at the time of mold clamping, and an insert part (b) is provided in the cavity (4). In the molding die (a) having the insert component (b) integrally formed by filling the cavity (4) with the molding material (d). A mold (2) is provided with a gap (9) for communicating the cavity (4) and the burr groove (5) with each other.