JPS60154020A - Formation of ring-shaped molding - Google Patents

Abstract

PURPOSE:To enhance the productivity of a ring-shaped molding by a method in which a synthetic resin material charged into a pot portion is pressed by a lower mold having a part mold and the pot portion as cavity and an upper mold having a projection to be fitted into the pot portion while keeping a closed tiered portion and clearance and packed into the part mold. CONSTITUTION:A given amount of a synthetic resin material 7 is weighted and charged into a pot portion 3, and an upper mold 4 and a lower mold 1 are matched with each other and close. The resin material 7 is overflowed into a part mold 2 from the pot portion 3 along the aperture 8 between the inner surface of the pot portion 3 and the outer surface of the projection 6. The overlow of the resin material 7 is completely interrupted and closed by contact of a closed tiered portion 5 provided on the projection of the upper mold 4 with the surface of the lower mold 1. The action of an indentation allowance 9 provided on the outside peripheral edge of the mold 2 eliminate the needs to cut and remove disc gate in the ring-shaped molding and forms a smoothened face requiring no finishing process on the inside and outside peripheral edges.

Description

[Detailed description of the invention] This invention uses synthetic resin, especially thermosetting resin, as a whole material.
For example, it relates to a method for molding ring-shaped molded products such as bearing supports.

Various molding methods, such as transfer molding and pressure molding, have been applied to molding conventionally shaped molded products. However, when molding engineered plastic materials using the molding method, fibrous fillers such as glass fibers and asbestos fibers are used to improve strength, so for ring-shaped molded products, one transfer method is required. A common method is to provide a film in the center, perform all molding using a center gate method, and then cut and remove the disk gate in post-processing. Also, ring-shaped molded products, especially thin-walled molded products, by force-pressure molding.

Fibers appeared on the surface, causing many problems in terms of appearance and performance.

The present invention takes advantage of the characteristics of the transfer molding method that prevents fiber filler from appearing on the surface, and the characteristics of pressure molding that prevents the appearance of weld lines, which cause deterioration of physical properties, and further improves the structure of the mold to process the gate. It is made using a molding method that does not require.

The ring-shaped molded product in the present invention is not limited to simply a circular ring, but may also be an elliptical ring, a polygonal ring, or a bent ring. Further, its cross section is not limited to the shape shown in the drawings.

Referring to Fig. 1, a lower mold l made of a highly rigid material such as metal
A molded product molding part 2 having a ring shape and a pot part 3 having the same shape as the inner space are provided as a cavity,
The upper mold 4 has a closing step 5.

A convex part 6 is provided to be recessed into the pot part 3 while maintaining a distance from the side surface of the pot part 3, a synthetic resin material 7 is put into the pot part 3, and the upper mold 4 is lowered to form a second part. As shown in the figure, the upper mold 4 and the lower Wit are fitted together, and at this time, there is a
Since a slight gap 8 is formed, as the convex part 6 of the upper part 4 sinks into the pot part 3 of the lower mold l, the synthetic resin material 7 introduced into the pot part 3 gradually passes through the gap 8. The fluid overflows and flows into the molded product forming part 2, gradually filling the molded part 2.

When the upper mold 4 and the lower mold l are completely fitted and closed, the molded product mold part 2 is completely filled with synthetic resin material, and the synthetic resin material from the pot part 3 is completely filled, as shown in FIG. The overflow of the synthetic resin material 7 in the gap 8 is caused by the closure step 5 provided on the convex part 6 of the upper mold 4 coming into contact with the surface of the lower mold 1.
' and the synthetic resin material 7 filled in the J molding part 2, and the connection between the two is completely cut off. In addition, on the outer peripheral edge of the molded product mold part 2 in the lower mold l,
A pushing allowance 9 for the upper die 4 is provided between the upper die 4 and the upper die 4 to prevent the synthetic resin material 2 from protruding, and to provide a pressurizing effect by mold clamping to the synthetic resin material filling the molded product mold part 2.

After the upper mold 4 and the lower mold 1 are completely fitted and closed in this way, the synthetic resin material is cured for a certain period of time, and the upper mold 4 is raised and uncoupled from the lower mold 1 to form a ring-shaped molded product. The molded product mold part 2 is also taken out, and the cured material, that is, the cull formed in the gap 8 is taken out from the pot part 3 to complete the molding. In the figure, lO is an ejector pin used to take out the ring-shaped molded product from the mold part 2, 11 is an ejector pin used to take it out from the full pot part 3, 12 is a stopper bolt, and 13 is a spacer. However, in the molding of a pufferfish-shaped molded product using the fiber fins that are the object of the present invention, a required amount of fiber filler,
In other words, synthetic resin materials such as glass fibers, carbon fibers, asbestos fibers, or synthetic resins mixed together and pre-cured into a tablet form, and pastes and putty in which fiber fillers are kneaded into the synthetic resin in advance. Using the so-called premix, a ring-shaped molded product is molded according to the molding method described above.

Since the method for molding a ring-shaped molded product of the present invention is similar to the above-described configuration, a predetermined amount of the synthetic resin material 7 weighed in advance is put into the pot part 3, and the upper mold 4 and the lower mold 1 are fitted together. By fitting and closing the pot part 3, the synthetic material overflows from the pot part 3 into the mold part 2 through the gap 8 between the inner circumferential surface of the pot part 3 and the outer circumferential surface of the convex part 6 of the upper die 4. The flow of the resin material 7 is completely blocked and closed by the closing step 5 provided on the upper mold convex part coming into contact with the surface of the lower mold l, and the closing step 5 provided on the outer peripheral edge of the molded product part 2 Due to the push-in allowance 90,
Ring-shaped molded products can of course be used to cut and remove disc gates.
Both the inner and outer peripheral edges form smooth surfaces that do not require finishing.
The amount of cull formed in the gap 8 with the outer peripheral surface of is the total minimum,
In order to reduce the loss of the synthetic resin material 7, it is desirable that the depth of the pot part 3 is as shallow as necessary and sufficient, and the gap formed between the pot part 3 of the lower mold 1 and the convex part 6 of the upper mold 4 is 8
It is necessary to make the gap as narrow as possible, and as a result of various studies, it was found that approximately 0.5 tone is appropriate. Since the flow resistance within the range is different, it is necessary to take into account the following factors when deciding.

As described in detail above), the molding method of the ring-shaped molded product of the present invention eliminates disc gates and burrs that cannot be avoided by conventional molding methods, completely reduces or eliminates the finishing process, and eliminates the occurrence of cracks and molding. This prevents reinforcing fibers from being exposed on the surface of the product and allows the worker to simply put the pre-measured synthetic resin material into the bottom pot and close the upper and lower molds completely. By simply performing operations, it is possible to quickly mold ring-shaped molded products that do not require deburring or finishing process, and improve productivity by completely reducing or eliminating post-molding processes. , it is possible to save labor.

[Brief explanation of drawings]

Are Figures 1 to 3 examples of the present invention? Figure 1 is a front sectional view showing when the upper and lower molds are open. Figure 2 shows when the upper and lower molds are mated and the closure is halfway progressed.
FIG. 3 shows the state when the upper mold and lower mold are completely fitted and closed. 1 Lower mold 2... Molded product mold part 3... Bot part 4... Upper mold 5... Closing step part 6... Convex parts 7, 7', 7... Synthetic resin material 8... Gap
9...Pushing distance 10, 11...Eject pin 12...Stopper bolt 13...Spacer patent applicant Otalite Co., Ltd. agent Patent attorney Katsu Ohno Reiko Ohno Ryunosuke Ohno

Claims (1)

[Claims] A lower mold has a mold part and a pot part having the same shape as the inner space of the molded part as a cavity, and a closed step part, and the mold part is immersed into the pot part while maintaining a distance from the side surface of the pot part. A method for molding a ring-shaped molded product, characterized in that the entire synthetic resin material charged into the pot section is pressurized by the upper mold having a convex part thrown thereon, and the synthetic resin material is allowed to overflow and fill the entire molded product mold section. .