JPS63128916A - Transfer molding equipment - Google Patents

Abstract

PURPOSE:To prevent cold shuts and cracks from generating by a method wherein molten raw rubber or resin is uniformly and easily forced through gates in respective parts in a cavity from a cylinder space, which is formed by a top and a bottom forces on the rear side of the boundary surface of the top and the bottom forces. CONSTITUTION:Raw rubber is softened or melted by beat and filled in a cylinder space 7. The raw rubber is held at a temperature exceeding its softening or melting temperature by means of hot plates 4a and 4b. Next, a piston 8 is moved forward by means of a hydraulic device 13 for pressing. As a result, softened or molten raw rubber is poured from a large number of gates 6b provided at the rear end of a cavity through collar forming parts 6a into the cavity 6. Since the pouring of the rubber is done through all the collar forming parts 6a, the whole cavity 6 is uniformly filled with the rubber. Since the top and the bottom forces are held at high temperature as they are heated, the raw rubber is vulcanized. After the completion of vulcanization, the piston 8 is retreated by means of the pressing device 13 and at the same time the bottom force 3 is lowered by means of a hydraulic lift 9.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a transfer molding apparatus for producing molded products made of rubber or resin.

(Prior Art) As a transfer molding apparatus conventionally used for manufacturing, for example, insulating ceramic tubes having a large number of ends, there is a transfer molding apparatus divided into upper and lower stages.

That is, the transfer molding apparatus includes an upper mold and a lower mold equipped with a heating device, a pot for storing rubber in the upper part of the upper mold, and a press-fitting piston movable in the vertical direction above the pot. In this transfer molding device, the raw rubber is first placed in the pot, softened or melted by heating, and then press-fitted into the cavity formed by the piston in both the upper and lower molds through gates provided in both the upper and lower molds, where it is heated for a predetermined period of time. heated at a temperature. The rubber is then vulcanized and a rubber molded product is formed.

An example of the above-mentioned prior art is Japanese Patent Application Laid-Open No. 194403/1983.

Furthermore, in the case of a vertically elongated molded product having an axial center, a method has also been proposed in which raw rubber is press-fitted from one end in the axial direction.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, the number of man-hours from supplying the raw rubber to taking out the rubber mold is large (and the work is time-consuming,
This leads to an increase in costs, and since there are many parts, there is a problem in that foreign matter gets mixed in during the manufacturing process of the rubber mold, and furthermore, it is very difficult to clean the gate, piston, and pot formed in the upper mold.

In addition, in the method of press-fitting the raw rubber in the axial direction, the rubber flows well in the axial direction, but it is difficult for the rubber to flow into the cavity formed in the direction perpendicular to the axial direction, between the shaft part of the molded product and the cavity part in the perpendicular direction. There were problems in that the hot springs and cranks could get stuck in them, and that they could get damaged during use.

Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention forms a cavity with an upper mold and a lower mold, and forms a boundary surface between the upper and lower molds on the rear side of the cavity. , a cylinder space for press-fitting rubber or resin is formed, and the cylinder space and the cavity are communicated by a gate at the interface between the upper and lower molds, and a piston is mounted so as to be movable back and forth with respect to the cylinder space. We have adopted a configuration in which the following is provided.

(Function) By adopting the above configuration, molten raw rubber or resin is transferred from the cylinder space formed by the upper and lower molds on the rear side of the interface between the upper mold and the lower mold to each part in the cavity via the gate. It is press-fitted uniformly and easily to form a rubber or resin mold.

(Example) An example in which the invention is embodied in an insulating porcelain tube will be described below with reference to FIGS. 1 to 7.

The insulator tube manufactured in this example contains an insulating rod in the center and is used for supporting electric wires in power transmission and distribution lines.

As shown in Fig. 1, an upper mold 2 is supported and fixed at the top of the four legs l, and a lower mold 3, which is also supported by the legs 1 and can move up and down, is arranged below it. has been done. Upper mold 2
is heated by a hot plate 4a whose temperature is raised by a heater. The same type 2 has thermocouples 5 for measuring the heating temperature of each part.
A is attached.

On the other hand, the temperature of the lower mold 3 is also raised by the heater 4b.
heated by. The same lower mold 3 is equipped with a thermocouple 5b for measuring the heating temperature of each part.
A cavity 6 is formed between the upper mold 2 and the lower mold 3, in which a molded product as an insulator tube is manufactured when both molds are brought into close contact with each other.

To explain the lower mold 3, as shown in Fig. 2, a semi-cylindrical cavity 6 long from left to right is formed in the front part of the lower mold 3, and the cavity 6 has many semi-circular annular holes spaced at equal intervals. The forming portion 6a is formed to be substantially perpendicular to the axial direction. A cylinder space 7 for accommodating the raw rubber is formed at the rear of the lower mold 3, and a piston 8 for press-fitting the raw rubber in the cylinder space 7 into the cavity 6 is installed on the rear side of the cylinder space 7 under hydraulic pressure. It is mounted so that it can be moved forward and backward by a device 13.

The hydraulic system W 13 includes a hydraulic cylinder 14 , a piston 15 installed inside the cylinder 14 so as to be movable back and forth, and a bushing rod 17 fixed to the piston 15 and connected to the piston 8 via a guide flange 16 . It's getting better. 18 is a guide frame that guides the guide flange 16.

Furthermore, when viewed from the side, the cavity 6 formed in the front part of the lower mold 3 has a cavity 6 in the center as shown in FIG.
A semicircular brim forming part 6a is formed on both sides thereof, and the rear end of the brim forming part 6a is communicated with the cylinder space 7 through a gate 6b.

Also, a sendrel support part 11 that supports the mandrel lO shown in FIG. 7 inserted into the center of the insulator tube as a molded product.
A mandrel lO is formed at both left and right ends of the cavity 6 so as to be movable upward. Furthermore, the lower die 3 can be moved up and down by hydraulic lifting a9 as shown in FIG.

On the other hand, as shown in FIG. 4, the upper mold 2, like the lower mold 3, has a cavity 6 formed with a gap formation part 6a and a gate 6b. Furthermore, a seventh hole is placed on the outer side of the cavity 6 of the upper mold 2.
As shown in the figure, a die cutting device 12 is provided to support the mandrel IO.

Next, the operation of the above embodiment will be explained.

First, raw rubber (solid material) is placed in the cylinder space 7 of the lower mold 3, and then the lower mold 3 is pushed up by the hydraulic elevator 9, so that it comes into close contact with the upper mold 2, as shown in FIG. Then, the raw rubber is softened or melted by heat and fills the cylinder space 7. The raw rubber is maintained at a softening or melting temperature or higher by the hot plates 4a and 4b.

Next, the piston 8 is moved forward by the hydraulic device 13, pushing the softened or melted raw rubber forward. Then, the softened or melted raw rubber is injected into the cavity 6 through a large number of gates 6b and empty forming portions 6a provided at the rear end of the cavity 6.

Since the softened or melted raw material rubber is injected through all the end forming parts 6a, the entire cavity 6 is filled uniformly. Since the upper mold 2 and the lower mold 3 are maintained at a high temperature while being heated, the raw rubber is vulcanized.

After vulcanization is completed, the piston 8 is retracted by the hydraulic device 13 and the lower mold 3 is moved to the sixth position by the hydraulic elevator 9.
It is pulled down as shown.

Then, the insulator tube, which is a molded product, is first released from the upper mold 2 by the mold cutting device 12. Furthermore, when the lower mold 3 is lowered, the mandrel 10 that has passed through the center of the molded product is engaged with the lower end of the mold cutting device 12 provided at positions corresponding to both ends of the mandrel 10, so that the mandrel IO is lowered further. do not.

Therefore, the molded product is smoothly released from the lower mold 3 as well.

The released molded product is taken out by holding both ends of the mandrel 10, and the mandrel 10 is extracted from the molded product to obtain the desired rubber molded product as an insulator tube having a large number of ribs.

In the transfer molding apparatus of this embodiment, when the mold is opened, all of the cylinder space 7, piston 8, gate 6b, and cavity 6 are exposed on the mold opening surface, so cleaning is very easy. Furthermore, the number of man-hours required to take out the rubber or resin mold is short, and the work is not time-consuming, so the resin or rubber mold can be manufactured at a low cost. Furthermore, since there are fewer members, there is no possibility of foreign matter getting mixed in during the manufacturing process of the rubber or resin mold. The rubber mold thus obtained has accurate dimensions, uniform density, and high strength. The transfer molding apparatus of the present invention is preferably used for insulators having complex structures and shapes.

The present invention is not limited to the above embodiments, but can also be implemented as follows.

(1) In the above embodiments, rubber was used as the material for the molded product, but other than rubber, resins such as FRP may also be used.

(2) In the above embodiment, the transfer molding device was used for manufacturing insulating insulating tubes, but it can also be used for various other applications such as automobile parts and electrical products.

Effects of the Invention The transfer molding device of the present invention has a simple structure with upper and lower stages, and the number of man-hours required to take out the rubber or resin from the mold is short, and the work is not time-consuming. In addition to manufacturing a mold of 100 mm, it is very easy to clear the cylinder space, piston, gate, and cavity on the mold opening surface by 1 m.

In addition, since there are fewer members, there is an excellent effect that no foreign matter is mixed in during the manufacturing process of rubber or resin molds.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing the transfer mold device of the present invention; Fig. 2 is a perspective view showing the lower mold;
The figure is a perspective view from the side showing the lower mold, Fig. 4 is a perspective view showing the upper mold, Fig. 5 is a perspective view showing the upper mold and lower mold in close contact, and Fig. 6 is the lower mold after molding. FIG. 7 is a perspective view showing a state in which the lower die is pushed down to the lower end after molding. 2... Upper mold, 3... Lower mold, 6... Cavity, 6
a...Brim forming part, 6b...Gate, 7...Cylinder space, 8...Piston

Claims (1)

[Claims] 1. A cavity (6) is formed by the upper mold (2) and the lower mold (3), and both upper and lower molds (2, 3) are placed on the back side of the cavity (6).
A cylinder space (7) for press-fitting rubber or resin is formed at the boundary surface, and a gate (6b) is formed between the cylinder space (7) and the cavity (6) at the boundary surface between the upper and lower molds (2, 3). ), and is further provided with a piston (8) which is attached to the cylinder space (7) so as to be movable back and forth.