JPS6350091Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molding die that prevents excess rubber from flowing into the reinforcing ring portion when a rubber material is molded onto the end of the reinforcing ring.

Conventionally, as shown in FIG. 1, in order to mold a rubber material to the end of a reinforcing ring 4, an injection mold 1, an upper mold 2 below it, and a lower mold 3 below it have been used. A cavity 5 is formed between the upper mold 2 and the lower mold 3, and one end of the reinforcing ring 4, which is pressed and fixed by the upper and lower molds 2 and 3, projects into this cavity. A pocket portion 15 constituting a rubber material placement portion is formed on the upper surface of the upper mold 2, and a rubber material is placed in the pocket portion. The rubber material is injected into the cavity 5 through an injection gate 7 formed in the upper mold 2 under pressure from the injection mold 1, and is vulcanized. In the above method, the reinforcing ring 4 is pressed between the upper mold 2 and the lower mold 3 at the time of injecting the rubber material, so that when the rubber material is injected into the cavity, the rubber material is inserted into the reinforcing ring. The phenomenon of excess rubber flowing out around the parts 4, which is usually called burr, does not occur. However, the above method requires the injection mold 1 in addition to the upper mold and the lower mold, which has the disadvantage that the weight of the entire mold becomes heavy.In addition, the amount of rubber material used is large, and the molding There was a drawback that it caused damage to the gate part of the product.

In the molding method shown in FIG. 2, the injection mold 1 described above is not used. Further, a pocket portion 15 constituting a rubber material placement portion is formed on the upper surface of the lower mold 3. When this rubber material flows into the cavity 5 due to the compression action of both the molds 2 and 3, the reinforcing ring 4 is still not pressed and held between the upper mold and the lower mold. Therefore, a phenomenon of rubber flow occurs in which the rubber material in the cavity 5 flows out around the reinforcing ring 4.

The purpose of this invention is to use the method shown in Fig. 1 and the method shown in Fig. 2 above when molding rubber material at the end of a reinforcing ring using only an upper mold and a lower mold without using an injection mold. It is an object of the present invention to provide a molding die that does not have the defects caused by the method.

That is, according to the present invention, there is an upper mold and a lower mold, and these molds have a clamping part for clamping the reinforcing ring at a position adjacent to a cavity formed between the two molds. In this molding die, the upper die has a first part and a second part, and the first part has an elasticity within an elastic limit. has a flexible portion that bends and is connected to the second portion via the flexible portion;
The clamping part is provided on the lower surface of the second part and the upper surface of the lower mold opposing thereto, and the relative dimensions of the first part, the second part, and the lower mold are reinforced by the clamping part. When the ring is held and the flexible portion is in an unflexed state, a gap communicating with the cavity is formed between the lower surface of the first portion and the upper surface of the lower mold opposing thereto. In addition, a rubber material placement portion is provided on the upper surface of the lower mold at a position opposite to the lower surface of the first portion and adjacent to the cavity, so that elastic deflection of the flexible portion is caused from the above state. When the first part and the lower mold are brought relatively close together and the lower surface of the first part and the upper surface of the lower mold are brought into contact with each other, the rubber material is attached to the rubber material placing part and the first part facing thereto. is injected into the cavity while being compressed between the lower surface of the second part and the second part due to the elastic deflection of the flexible part, which increases the clamping force with which the reinforcing ring is clamped by the clamping part. Provided is a molding die characterized in that it has a configuration in which the following can be added.

Next, an embodiment of the present invention will be described with reference to FIGS. 3 and 4. A lower die 3 is fixed to a lower press plate 10, and an upper die 2 and an upper press plate are arranged above the lower die. A cavity 5 is formed between the upper surface of the lower mold 3 and the lower surface of the upper mold 2. A reinforcing ring 4 is placed on the upper surface of the lower mold 3, and one end of the reinforcing ring 4 is inserted into the cavity. Rubber material 1
6 is placed on the rubber material placement portion on the upper surface of the lower mold 3.

Press the upper plate 9 on the upper surface of the first part 11 of the upper mold 2.
3, a gap δ exists between the upper surface of the second portion 12 of the upper mold 2 and the upper plate 9. Furthermore, a gap δ is also provided between the lower surface of the first portion 11 of the upper mold 2 and the upper surface of the lower mold 3.
The first part 11 of the upper mold 2 has a flexible part 6 that can be elastically deformed, and the second part 11 has a flexible part 6 that can be elastically deformed.
It is connected to part 12. In the state shown in FIG. 3, one end of the gap between the lower surface of the first portion 11 and the upper surface of the lower mold 3 communicates with the cavity 5.

When the lower press plate 10 is raised, the lower mold 3 and the second part 12 of the upper mold 2 come into contact, and the clamping part or pressing part 14 located on the left side of the cavity on the upper surface of the lower mold 3 The reinforcing ring 4 is held and fixed between a holding part or a pressing part 13 on the lower surface of the second part 12 of the mold 2. When the lower press plate 10 is further raised, the upper surface of the first portion 11 of the upper mold 2 comes into contact with the upper press plate 9, resulting in the state shown in FIG. 3. At this time, a load is applied to the first portion 11 of the upper mold 2 due to contact with the press upper plate 9, and the load is applied via the flexible portion 6.
The reinforcing ring 4 is further pressed by the pressing portion 13 . When the press lower plate 10 further rises and a load is applied to the first portion 11, the flexible portion 6 is elastically deformed and deformed using the cavity side of the reinforcing ring 4 as a fulcrum A, and the load at this fulcrum A is becomes larger, and the flow of excess rubber from here is further blocked. Furthermore, the press lower plate 10 rises, and the flexible part 6
is elastically deformed and the gap δ disappears, the lower surface of the upper mold and the upper surface of the lower mold are all in close contact, and the upper surface of the lower mold 3 faces the lower surface of the first part 11 and is adjacent to the cavity 5. The rubber material 16 placed on the rubber material placement portion provided at the position flows into the cavity 5, and the cavity 5 is closed by the upper and lower molds 2 and 3. As mentioned above, at this time, in addition to the load due to the press operation, the reaction force of the elastic deformation of the flexible portion 6 is applied to the second portion 12 of the upper mold 2, and the second portion 12 of the upper mold 2 is The clamping force for clamping the reinforcing ring 4 increases. Since the reinforcing ring 4 is thus strongly pressed by the upper mold and the lower mold, the surplus rubber material does not flow out around the reinforcing ring 4. During the above operation, the flexible portion 6 of the upper mold 2 is bent within the elastic deformation limit due to the pressing force of the press, and the lower surface of the first portion 11 of the upper mold 2 comes into contact with the upper surface of the lower mold 3. At the beginning of the press operation (Fig. 3), the pressing part of the second part 12 of the upper die 2 is connected to the lower die 3 and the reinforcing ring 4.
However, a gap δ exists between the second portion and the press upper plate 9. On the other hand, a gap δ exists between the first portion of the upper mold 2 and the lower mold 3. However, in the forming stage of press work (Fig. 4), the upper and lower molds are
are in close contact with each other so as to sandwich a part of the reinforcing ring 4, and the elastic deformation force of the flexible portion 6 is applied to the pressing portions 13 and 1.
4 increases the clamping force for clamping the reinforcing ring 4. Further, a cut groove 8 is provided in a part of the cavity 5, and burrs are intentionally generated therein so that the molded product can be easily removed after the molding operation.

As mentioned above, the molding die of the present invention can prevent excess rubber material from flowing out from the reinforcing ring, thereby saving rubber material and improving the finish of the molded product, making it easier to attach it to other parts. This has the effect of improving fitting performance. Furthermore, since no injection mold is used, the weight of the molding die and equipment costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional molding die, FIG. 2 is a cross-sectional view of another conventional molding die, and FIG. 3 is a cross-sectional view of a molding die embodying the present invention at an initial working stage.
FIG. 4 is a sectional view at the molding stage. 2... Upper mold, 3... Lower mold, 4... Reinforcement ring,
5... Cavity, 6... Flexible portion, 11... First part, 12... Second part.

Claims (1)

[Scope of utility model registration request] It has an upper mold and a lower mold, and these molds have a clamping part for clamping the reinforcing ring at a position adjacent to the cavity formed between the two molds, and a clamping part for clamping the reinforcing ring at the end of the reinforcing ring. In a molding die adapted to pressure mold a rubber material, the upper die has a first part and a second part.
the first part has a flexible part that flexes within elastic limits and is connected to the second part via the flexible part, and the first part has a lower surface of the second part and an opposite part thereof. The clamping part is provided on the upper surface of the lower mold, and the relative dimensions of the first part, the second part, and the lower mold are such that the reinforcing ring is clamped by the clamping part and the flexible part When the first part is in an unflexed state, a gap communicating with the cavity is formed between the lower surface of the first part and the upper surface of the lower mold opposing thereto, and the lower mold A rubber material placement part is provided on the upper surface at a position opposite to the lower surface of the first part and adjacent to the cavity, and from the above state, the first part and the lower mold are connected while causing elastic deflection of the flexible part. When bringing the lower surface of the first part relatively close to the upper surface of the lower mold, the rubber material is compressed between the rubber material mounting part and the lower surface of the first part facing it. The reinforcing ring is injected into the cavity, and a pressing force is applied to the second portion by elastic deflection of the flexible portion to increase the clamping force for clamping the reinforcing ring by the clamping portion. A mold for molding.