JPH0529525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method of manufacturing a suspension insulator provided with an insulating support tube for incorporating a lightning arrester element in the shade.

(Conventional technology) In order to prevent the insulator device from being destroyed by high voltage when lightning strikes a power transmission line, etc., a lightning arrester element with voltage non-linearity whose main component is zinc oxide etc. is placed in parallel with the insulator. It is already known that the lightning voltage can be released to the ground (for example, the
Publication No. 31456). Conventionally, such lightning arresting elements were usually provided separately from the insulator, but recently attempts have been made to incorporate the lightning arresting element into the insulator shade. However, in this case, it is necessary to provide an insulating support tube in the insulator cap to house the lightning arrester, so holes are made in the green insulator cap, which has been rotary press-molded using a forming trowel called a round trowel. After drilling and firing, the hole is polished, and then an insulating support cylinder, which is molded and fired in a separate process, is fitted into the hole, coated with glaze, etc., and re-fired to join. The drawback was that the process was complicated and the manufacturing cost was high.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems and manufactures a suspension insulator in which a suspension type lightning arrester having an insulating support tube for storing a lightning arrester element in an insulator shade part can be integrally molded. It has been completed to provide a method.

(Means for Solving the Problems) The present invention, which has been made to solve the above-mentioned problems, involves putting clay into the inside of a breathable molding lower mold having an uneven shape corresponding to the outer surface shape of the insulator. The molding surfaces of the breathable presser foot and the molding lower mold are preliminarily pressed while applying negative pressure from inside, and then the presser foot is released from the molded product with positive pressure, and the non-breathable rotary iron is lowered. The molded product in the lower mold is preformed while maintaining a negative pressure on the inner surface of the lower mold, and the air-permeable molding trowel 10, which has an uneven shape corresponding to the shape of the inner surface of the insulator, is lowered to form the molding trowel. It is characterized by press forming while applying negative pressure to the inner surface of the molding iron, and then applying positive pressure to the inside of the molding iron to separate it from the molded product.

(Example) Next, the present invention will be described in detail with reference to the drawings.

First, as shown in FIG. 1, clay 1 as a raw material is molded using a lower mold 2 and an upper mold 3. Lower mold 2
is made of a breathable material and has a gentle ridge 4 on its upper surface. As shown in the figure, the upper mold 3 has a concave portion 5 that roughly corresponds to the outer surface shape of the suspended insulator.When the upper mold 3 is heated to several hundred degrees Celsius and rotated while pressing the clay 1, the clay is formed. 1
The surface loses moisture and rapidly solidifies, forming clay molded into a moke shape. At this time, the molding surface of the lower mold 2 is subjected to negative pressure from inside, so that the molding surface can be quickly molded into an accurate shape without producing bubbles or "sink marks" on the molding surface.

Next, as shown in FIG. 2, the lower mold 2 is inverted and moved to above the molding lower mold 6 while keeping the molded clay 1 adsorbed. The lower mold 6 is also made of a breathable material and has a concavo-convex shape that precisely corresponds to the shape of the outer surface of the insulator. Further, a cylindrical protrusion 7 having a predetermined diameter is fitted into a portion where an insulating support cylinder is to be formed. The molded clay 1 is released from the lower surface of the lower mold 2 by air blowing the molded product by lowering the inverted lower mold 2 and switching from negative pressure to positive pressure. Injected.

Next, as shown in FIG. 3, the molding lower die 6 is placed opposite to the lower side of the breathable presser foot 8, and the clay 1 is preliminarily pressed by the presser foot 8. The presser foot 8 has a raised part larger than the lower mold 2 described above, and during the preliminary presser period, the inside of the molding lower mold 6 and the presser foot 8 are both kept under negative pressure, and the molding surface is depressurized so that there are no bubbles or sink marks. Form into exact shape. Thereafter, the presser foot 8 is raised while keeping the inside of the molding lower die 6 at a negative pressure and the inside of the presser foot 8 is made positive pressure, and the molded product remains adsorbed inside the molding lower mold 6.

Next, as shown in FIG. 4, the lower molding mold 6 is placed opposite to the lower part of the rotary trowel 9 made of non-porous material such as metal, and the lower molding mold 6 is rotated by the rotary trowel 9 while maintaining negative pressure from inside. Perform rotary press molding. During this time, the molded product remains attracted within the lower mold 6, so that even if it comes into contact with the rotary iron 9, it will not be displaced within the lower mold 6. This preforming causes the upper surface of the molded product to more closely resemble the shape of the inner surface of the insulator.

Next, as shown in FIG. 5, the lower mold 6 is placed opposite to the lower part of the molding iron 10. The forming trowel 10 is made of a breathable material having a concavo-convex shape that exactly corresponds to the shape of the inner surface of the insulator, and press forming is performed by lowering the forming trowel 10 in a stationary state. During press molding, negative pressure is applied to the molding surfaces of the lower molding die 6 and the molding trowel 10 from inside, and the molding is performed into an accurate shape that matches the surface shapes of the molding trowel 10 and the lower molding die 6. The forming iron 10 has a protrusion 11 for forming pin insertion holes in the center, an annular protrusion 12 for forming ribs on the periphery,
Furthermore, a protrusion 13 for forming an insulating support cylinder is provided at a position corresponding to the cylindrical protrusion 7 of the lower mold 6. Therefore, with this forming trowel 10, the shape of the suspension type lightning arrester is almost completed as shown in FIG. Release the product from the mold. The molded product obtained in this way is then punched out, that is, through-holes are formed in the insulating support tube using a rotating knife, and the necessary parts are finished, glazed, dried, fired, etc. to complete the product. It becomes a product.

As shown in FIG. 6, the finished product has a shape in which an insulating support tube 16 for storing a lightning arrester element is integrally provided on the cap of an insulator body 15 having a plurality of ribs 14.

In addition, as the breathable material used in the present invention, a material having communicating pores made by bonding inorganic particles with a synthetic resin, gypsum having communicating pores, and the like are used. The surface pore diameter is preferably 10 μm or less.

(Effects of the Invention) As described above, according to the present invention, the clay placed inside the breathable molding lower mold, which has an uneven shape corresponding to the outer surface shape of the insulator, is pre-pressed,
As the final shape is gradually approached through each stage of preforming and main forming, molding of the clay is easy and it becomes possible to integrally mold a lightning arrester with an insulating support tube for storing the lightning arrester. . Further, according to the present invention, since the clay is molded while keeping the inside of the molding lower mold under negative pressure, the outer surface shape of the insulator can be molded into an accurate shape, and the presser trowel for preliminary pressing can be used. During pressure molding, the molding trowel for this molding applies negative pressure to the molding surface from the inside to eliminate air, molds the molded product into an accurate shape that follows the surface of the mold or molding trowel, and then presses the molded product into the mold or trowel. When the molded product is separated from the molded product, compressed air is blown from the inside onto each molding surface to promote mold release and prevent deformation of the molded product, thereby significantly increasing molding accuracy. Therefore, a suspended insulator with deep irregularities can be easily and accurately formed. As a result, according to the method of the present invention, unlike the conventional method in which the insulator body and the insulating support tube are manufactured in separate processes and then joined with glaze, etc., the insulating support tube that houses the lightning arrester element is integrated. This allows for easy integral molding of the suspended insulator.

Therefore, the present invention greatly contributes to the development of industry as a method for manufacturing a suspended insulator that eliminates the problems of the conventional method.

[Brief explanation of drawings]

All drawings show embodiments of the present invention.
Fig. 1 is a sectional view showing the hook forming process, Fig. 2 is a sectional view showing the mold injection process, Fig. 3 is a sectional view showing the preliminary pressing process, Fig. 4 is a sectional view showing the preforming process, and Fig. 5 is a sectional view showing the preforming process. The figure is a sectional view showing the main molding process, and FIG. 6 is a partially cutaway perspective view showing the finished product. 1: Clay, 6: Lower mold, 8: Presser foot, 9: Rotating iron, 10: Molding iron.

Claims (1)

[Claims] 1 Put the clay 1 into the inside of the breathable molding lower mold 6, which has an uneven shape corresponding to the outer surface shape of the insulator,
The molding surfaces of the breathable presser foot 8 and molding lower mold 6 are preliminarily pressed while applying negative pressure from inside, and then the presser foot 8 is applied with positive pressure and separated from the molded product, and then the non-breathable rotary iron 9 is pressed. is lowered to preform the molded product in the lower mold 6 while maintaining the inner surface of the lower mold 6 under negative pressure, and furthermore, a breathable molding trowel 10 having an uneven shape corresponding to the shape of the inner surface of the insulator is used. Press forming is performed while lowering the molding iron 10 to create a negative pressure on the inner surface of the molding iron 10,
A method for manufacturing a suspended insulator, which comprises then applying positive pressure to the inside of the molding iron 10 to separate it from the molded product.