JPH0414852B2 - - Google Patents

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 articles made of rubber or resin.

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

That is, the transfer molding apparatus includes an upper mold and a lower mold each having a heating device, a pot for accommodating 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 into the upper and lower molds through gates provided on both the upper and lower molds, where it is held for a predetermined period of time. heated at a temperature of 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 conventional technology, the number of man-hours from supplying raw rubber to taking out the rubber mold is large, and the work is time-consuming, leading to increased costs. There is a problem that foreign matter gets mixed into the manufacturing process.
Furthermore, it was very difficult to clean the gate, piston, and pot formed in the upper mold.

In addition, in the method of press-fitting raw rubber in the axial direction, the rubber flows well in the axial direction, but it is difficult for the rubber to flow in 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 with hot water and cracks getting into the product, and damage during use.

Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention includes a cavity that is vertically elongated in the left-right direction on the interface between the upper mold and the lower mold, and a cavity on the rear side of the cavity. A cylinder space for press-fitting the molding material located therein and a plurality of gates scattered along the longitudinal direction of the cavity to communicate the cavity and the cylinder space are formed, and a piston is movable back and forth within the cylinder space. At the same time, the front surface of the piston faces the cylinder space side opening of each of the gates in the front-rear direction at approximately equal intervals.

(Function) By employing the above configuration, when the piston is moved forward, the molding material is uniformly and easily press-fitted from the cylinder space into each part of the cavity via the plurality of gates. Furthermore, there is no risk of foreign matter getting mixed into the molding material when it is press-fitted into the cavity from the cylinder space, and the cavity, gate, etc. can be easily cleaned by opening both the upper and lower molds.

(Example) An example in which the present invention is embodied in a molding apparatus for 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 shelves 1, 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. The upper mold 2 is heated by a hot plate 4a whose temperature is raised by a heater. The mold 2 is equipped with a thermocouple 5a for measuring the heating temperature of each part.

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

To explain the lower mold 3, as shown in FIGS. 2 and 3, a semi-cylindrical cavity 6 that is long from side to side is formed in the front part of the lower mold 3, and a large number of cavities 6 are formed at equal intervals. Semi-circular collar forming part 6a
is formed to be substantially perpendicular to the axial direction. A rectangular cylinder space 7 for accommodating raw rubber is formed at the rear of the lower mold 3 with its front side parallel to the axial direction of the cavity 6. The side ends are communicated through a gate 6b. A piston 8 for press-fitting the raw rubber in the cylinder space 7 into the cavity 6 is mounted on the rear side of the cylinder space 7 so as to be movable back and forth by a hydraulic device 13. The piston 8 is formed into a rectangular parallelepiped that fits into the cylinder space 7, and its front surface facing the opening on the cylinder space 7 side of each gate 6b is parallel to the front side surface of the cylinder space 7.

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

In addition, mandrel support parts 11 that support the mandrel 10 shown in FIG.
A mandrel 10 is formed to be movable upward. Furthermore, the lower mold 3 can be moved up and down by a hydraulic elevator 9, 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 collar forming part 6a and a gate 6b. Further, as shown in FIG. 7, die cutting devices 12 for supporting the mandrel 10 are provided on both outer sides of the cavity 6 of the upper die 2. As shown in FIG.

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

First, raw rubber (solid) is placed in the cylinder space 7 of the lower mold 3, and then the lower mold 3 is moved to the hydraulic elevator 9.
When the upper mold 2 is pushed up by the
Close contact with. Then, the raw rubber is softened or melted by heat and fills the cylinder space 7. The raw rubber is maintained at a temperature higher than its softening or melting temperature by the hot plates 4a and 4b.

Next, the piston 8 is moved forward by the hydraulic device 13 to press the softened or melted raw rubber forward. Then, the softened or melted raw rubber passes through a large number of gates 6b provided at the rear end of the cavity 6.
It is injected into the cavity 6 through the collar forming part 6a.

Since the softened or melted raw rubber is injected through all the collar forming parts 6a, the entire cavity 6 is filled uniformly. The upper mold 2 and lower mold 3 are maintained at a high temperature in the heated state, so
The raw rubber is vulcanized. After vulcanization is completed,
The piston 8 is retracted by the hydraulic device 13, and the lower die 3 is lowered by the hydraulic elevator 9 as shown in FIG.

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 10 is lowered no further. do not. Therefore, the molded product can be 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, thereby obtaining the desired rubber molded product as an insulator tube having a large number of flanges.

In the transfer molding apparatus of this embodiment, when the mold is opened, the cylinder space 7, piston 8, gate 6b, and cavity 6 are all 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 device of the present invention is preferably used for insulators with 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 can 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 As detailed above, according to the present invention, the cavity, the cylinder space, and the gate communicating between them are integrally formed on the interface between the upper and lower molds. Unlike the conventional method, which required time-consuming work such as aligning the gate,
Forming a flow path for the molding material is completed by simply combining the upper and lower molds, allowing easy molding with fewer man-hours and eliminating the risk of foreign matter getting mixed in during the molding process. In addition, the cavity, cylinder space, gate, and piston can be exposed easily and simultaneously by simply opening both the upper and lower molds, so cleaning work after use can be easily performed. Moreover, when the piston moves forward, the molding material is uniformly press-fitted from the cylinder space into each part of the cavity through multiple gates, which has the excellent effect of eliminating the risk of hot spots or cracks occurring in the finished molded product. play.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view showing the transfer molding apparatus of the present invention, Fig. 2 is a perspective view showing the lower mold, Fig. 3 is a perspective view from the side similarly showing the lower mold, and Fig. 4 is a perspective view showing the lower mold. Fig. 5 is a perspective view showing the upper mold and the lower mold are in close contact with each other, Fig. 6 is a perspective view showing the state where the lower mold is slightly pressed down after molding, and Fig. 7
The figure is a perspective view showing a state in which the lower mold is pushed down to the lower end after molding. 2... Upper mold, 3... Lower mold, 6... Cavity, 6a...
Flange forming part, 6b...gate, 7...cylinder space,
8... Piston.

Claims (1)

[Claims] 1 At the interface between the upper mold 2 and the lower mold 3, a cavity 6 elongated in the left-right direction, a cylinder space 7 for press-fitting molding material located at the rear side of the cavity 6, and a cylinder space 7 for press-fitting the molding material located on the rear side of the cavity 6, and a cavity 6 extending along the longitudinal direction of the cavity 6. A plurality of gates 6b are formed to be scattered and communicate between the cavity 6 and the cylinder space 7, and a piston 8 is mounted in the cylinder space 7 so as to be movable back and forth, and the front surface of the piston 8 is connected to each of the gates. A transfer molding apparatus characterized in that the transfer molding apparatus is arranged to face the opening on the side of the cylinder space 7 of 6a at approximately equal intervals in the front-rear direction.