JPS59152813A - Casting force for resin insulating support - Google Patents

Abstract

PURPOSE:To provide the titled casting force free from fault that would not cause a support insulator to have internal strains when a resin hardens and is high in strength, by letting a top force have a specified elastic member abutted against one surface of the top force, and a bottom force have a part that will be fitted slidably to a lower embedment metal fitment. CONSTITUTION:In casting forces wherein a bottom force 5 and a top force 10 are attached to a cavity mold 1 by bolts 9, 15, a lower embedment metal fitment 6 is not fixed by a bolt but is fitted to a recess 18 in the bottom force 5, and an embedment metal fitment 11 is fixed to the top force 10 by a bolt 19 through a packing 12. The bolt 19 is extended through a guide hole 20 in the middle of the top force 10, a ringlike elastic member 21 is placed around the bolt 19 with the member 21 in contact with the outer surface of the upper mold 10 and is held by a nut 22 provided to the bolt 19, and a synthetic resin (e.g. electrical insulating epoxy resins, etc.) is poured from an inlet 16 so as to form a support insulator 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synthetic resin casting mold for producing an electrically insulating molded article by injecting a synthetic resin liquid into the mold and curing the synthetic resin liquid.

Insulating supports such as support insulators for high voltage or ultra-high voltage are generally produced by pouring a liquid synthetic resin containing the ingredients for electrical insulation into a mold that can obtain the desired shape of the insulating support. Form by curing. In this case, the insulating support is usually integrally molded so as to incorporate embedded metal fittings for supporting and fixing it. For example, the molding method shown in Fig. 1 is adopted for supporting insulators having embedded metal fittings. There is.

In Fig. 1, the cavity mold 1 is divided into two parts.
They are fixed to each other with bolts and nuts in bolt mounting grooves 2 to form one casting mold. It also has a backing groove 3, in which the lower mold 5 into which the backing 4 is inserted and the lower embedded metal fitting 6 are fixed with bolts 8 via the backing 7, and the lower mold 5 is attached to the lower end surface of the cavity mold 1 with bolts 9. Fix it with.

Similarly, the upper mold 10 and the upper embedded fitting 11 are attached to the backing 12.
, and then fix it with bolts 13. Then, this upper mold 10
Place the backing on the top of the cavity mold (through the backing 14)
15, it is fixed to the upper end surface of the cavity mold 1. By injecting the synthetic resin liquid into the cavity mold 1 from the resin injection port 16 provided in the upper mold 10, the supporting insulator 17 is formed.

However, in the case of the above-mentioned deafness, during the curing process of the resin after injection, tensile stress is generated between the upper embedded metal fitting 11 and the lower embedded metal fitting 6 due to contraction of the resin, which tends to leave internal strain in the support insulator 17. However, there is a drawback that a decrease in mechanical strength of the support insulator 17 is unavoidable.

An object of the present invention is to eliminate the above-mentioned drawbacks and provide a resin casting mold for obtaining a support insulator with high strength and no defects without causing internal strain in the support insulator during curing of the resin. .

The present invention will be explained below based on examples.

FIG. 2 shows a sectional view of a casting mold according to the present invention, and the same reference numerals as in FIG. 1 are represented by the same names. The difference between FIG. 2 and FIG. 1 is that, first, the lower embedded metal fitting 6 is not fixed with bolts, but a recess 18 is provided in the lower mold 5, and the lower embedded metal fitting 6 is fitted into this. The second reason is the mounting force of the embedded fitting 11 to the upper mold 10. At 19, the upper embedded fitting 11 is fixed via the gasket 12, but in addition, the bolt 19 is attached to the upper mold 10. (located in the center of)
A ring-shaped elastic member 21 is installed on the outer periphery of the bolt 19 in contact with the outer surface of the upper mold 10 through the inner hole 20, and the elastic member is held down by a nut 22 provided on the bolt 19. Note that the lower mold 5 and upper mold 1O are attached to the capacity mold 1 using bolts 9 and 15.
Forming the support insulator 17 by injecting the liquid synthetic resin from the injection port 16 is exactly the same as in the case of FIG.

After assembling the casting mold as described above, for example, inject an electrically insulating epoxy resin containing 200 parts by weight of an inorganic filler to 100 parts by weight of epoxy resin and curing agent into the mold under vacuum. The curing of the epoxy resin molded product is accelerated by charging it into a 130° C. oven. The injected liquid resin becomes hard, and as it hardens, its viscosity increases, and in the process of transitioning from liquid to solid, volumetric contraction of the resin occurs9, which causes a gap between the lower embedded metal fitting 6 and the upper embedded metal fitting 11 to occur. Stress is generated due to the volumetric contraction of the resin, and due to the generation of this stress, the embedded fittings are pulled together. In this state, the upper embedded metal fitting 11 is pulled downward by the volumetric force of the resin. Due to this force, the elastic member 21 installed on the bolt 19 fixing the upper embedded metal fitting 11 is compressed, and the upper embedded metal fitting 11 moves downward in the direction of contraction of the resin. In addition, during this process, the bolt 19 that fixes the upper embedded metal fitting 11 is structured so that it only moves downward along the inner surface of the guide hole, so a dimensional error of the upper embedded metal fitting 110 in the horizontal direction occurs. Hateful.

On the other hand, the lower embedded metal fitting 6 is damaged by the force caused by the contraction of the resin.
being pulled upwards. At this time, the lower part embedding metal fitting 6 placed in the recess 18 provided in the lower mold 5 is guided by the inner surface of the recess 18 and moves upward, which is the direction in which the resin contracts, while sliding. Therefore, during this process, dimensional errors in the horizontal direction of the lower embedded metal fitting 6 are less likely to occur.

The mold after the resin injection is heated for about 15 hours, and when the resin in the mold has completely hardened, the upper embedded metal fitting 11 and the lower embedded metal fitting 6 are moved by the tensile stress caused by the contraction of the resin. Shown in Figure 3. After about 15 hours, the mold is removed from the heat curing furnace, the insulator is removed, and the molded support insulator 17 is taken out.

In the above embodiment, the lower embedded metal fitting 11 has a structure in which an elastic member 21 is interposed between the bolt 19 that is completely fixed and the upper mold 100 to allow the upper embedded metal fitting 11 to move. Upper embedded metal fitting 1
1 to the upper mold work 0 with bolts 13, and then attach the cavity mold 1
A kite bin 24, which is provided with an upper mold 10 having an upper embedded metal fitting 11 attached to an elastic member 21 installed in a groove n provided on the upper end surface and protruding from the upper part of the cavity mold 1, is inserted into the guide hole 25 of the upper mold 1. The upper mold 10 itself may be moved by sliding inside. Further, in both of the above two embodiments, the lower embedded metal fitting 6 is placed in the recess 18 provided in the lower mold 5, but as a different example, as shown in FIG. 5, a guide bin 26 is provided in the lower mold 5, The lower embedded metal fitting 6 can also be installed so that the guide bin 26 fits into the bottle hole 27 provided in the lower embedded metal fitting 6.

As explained above in the embodiments, according to the present invention, the embedded metal fitting on the upper part of the resin casting mold is fixed to the upper mold via an elastic member such as rubber or a spring, or the upper mold itself is fixed to the upper mold using an elastic member such as a spring. The lower part of the mold is made with a recessed part and the embedded metal fitting is fitted into it.
Alternatively, because the embedded metal fitting is not directly fixed to the lower part, such as by holding it with a guide bin, the upper part of the embedded metal fitting faces the direction of resin contraction in response to tensile stress caused by resin contraction that occurs during the curing process. It moves while compressing the elastic part,
In the lower part, the embedded metal fitting becomes movable along the inner wall of the recess or the guide bin. In other words, the formed insulating support is not mechanically constrained during the curing process and can move freely in the direction of resin contraction, making it easier to move than conventional casting molds in which the upper and lower embeddings are completely fixed to the mold. This has the advantage that the internal strain generated in the insulating support is significantly reduced. The insulating support obtained using the casting mold according to the present invention has 1.3 times the bending fracture strength and excellent insulation performance compared to the same product made using a conventional casting mold. It can be used as a high-quality electrical insulator. Furthermore, the casting mold according to the present invention can be easily modified from conventional molds, and the economic burden of adopting it is extremely small.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional casting mold, and FIG. 2 is a sectional view of a casting mold according to the present invention, which has an elastic member in the upper mold and a recess in the lower mold.
FIG. 3 is a sectional view of the casting mold similarly showing the operating state due to resin curing, and FIGS. 4 and 5 are sectional views of the casting mold showing an example different from FIG. 2. 1... Cavity type, 4, 7, 12. 14... Backing, 5... Lower mold, 6... Lower embedded metal fitting, 8
, 9 , 13, 15 , 19... Bolt, 10... Upper mold, 11... Upper embedded fitting, 16... Resin injection port, 17... Support insulator, 18... Recess, modification ...Guide hole, 21.Elastic member, 22..Nut, yoke...Groove,
24.26... Guide bin, 5... Guide hole, 27
...Bottle hole. Figure 1 t) Q/So Figure 2 22 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] l) A casting mold for producing a columnar resin insulating support consisting of an upper mold, a lower mold, and a cavity mold, and having embedded fittings facing each other on the upper and lower surfaces, It is characterized by having an elastic member that comes into contact with the upper or lower surface of the mold and provides elasticity against the lowering of the upper embedded metal fitting, and a part that is provided on the lower mold and slidably fits with the lower embedded metal fitting. A casting mold for the resin insulating support. 2. In the casting mold as set forth in claim 1, an elastic member is provided between the upper surface of the upper mold and a nut that penetrates the upper mold and engages with a pole IIC that fixes the upper embedded metal fitting at the lower end. A casting mold for a resin insulating support, characterized in that it is clamped. 3) The elastic member embedded in the upper surface of the cavity mold contacts the lower surface of the upper mold, and the guide pin protruding from the upper surface of the cavity mold slidably fits into the guide hole provided in the upper mold. A casting mold for resin insulating supports characterized by: 4) In the casting mold according to any one of claims 1 to 3, the lower embedded metal fitting has a pin hole that slidably fits into a guide pin protruding from the inner surface of the lower mold. A casting mold for a resin insulating support, characterized by: