JPH0326507A - Forming method for cylindrical part of suspension insulator with cylinder - Google Patents

Abstract

PURPOSE:To constitute the title method so that disconnection is not generated in the orientation of particles in body, by a method wherein press molding of the body loaded into a position corresponding to a cylindrical part forming an arrestor element holding part and monolithic molding of the cylindrical part having a partition wall at the central part are performed and the inside and partition wall of the cylindrical part are cut off with a cylindrical blade. CONSTITUTION:Pocket molding of body 1 becoming raw materials is performed with a hot-iron- type, rotating and pocket molding top force and porous and pocket molding bottom force 3. Then the body 1 is shifted to a main molding process by passing through a prepressing process and premolding process. A cylindrical part 10 having a partition wall 9 at the central part is molded integrally with an insulator main body 11 by being press-molded with a main molding top force 7, in relation to the body 1 in a molding bottom force 4. Then the partition wall 9 is removed by cutting off the inside of the cylindrical part 10 forming an arrestor element holding part with a rotating cylindrical blade. Then the cylindrical blade is lifted, a vacuum suction board is stuck close to the top of a molded product and the molded product is taken out from the molding bottom force 4 while performing air blowing. Then a core 6 is removed downward from the molded product along with the cut off partition wall 9 and becomes the penetrating cylindrical part 10.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to the shape of a cylindrical part of a cylindrical suspension insulator suitable for use as a suspension type lightning arrester insulator with a lightning arresting function by embedding a lightning arrester in the shade part. It is about the method.

(Prior 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-linear characteristics, mainly made of zinc oxide, etc., is placed in parallel with the insulator. For example, in order to release lightning voltage to the ground,
This is already known as shown in Publication No. 1456 and the like.
Conventionally, such lightning arresting elements were usually installed 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 the insulator cap with an insulating tube to house the lightning arrester, so for example, a hole is inserted into the insulator cap, which has been rotary pressed with a forming trowel called a round trowel, in the green state. After the burnout, the holes were polished and
The method used was to fill the hole with an insulating support tube that had been molded and fired in a separate process, then coated with glaze, etc., and then re-fired and joined. This had the disadvantage of complicating the manufacturing process and increasing manufacturing costs. Therefore, the present inventors first invented a method of integrally molding an insulator having a cylindrical part such as a lightning arrester storage part, and patent application No. 63-7
．． The application was filed as No. 205. This method, as shown in Fig.
After shaping, press molding is performed in a stationary state using an upper die (52) having a cylindrical projection (5l) corresponding to a cylindrical part such as a lightning arrester storage part, and a projection (51) is formed inside the molded product while it is soft.
) is to remove the clay remaining at the bottom of the lightning arrester and drill a hole in the cylindrical part that will serve as the lightning arrester housing. However, insulators manufactured by this method have a marked disorder in the orientation of the wire in the clay in the hole, which causes breaks in the hole, resulting in low strength in this area, and the inner lumen of the drilled part. It was found that there were many problems such as the need to finish the parts after drying. (Objective to be Solved by the Invention M) The present invention solves the above-mentioned conventional problems, and provides a suspension insulator having a cylindrical portion that forms a lightning arrester storage portion etc. The objective is to develop a method for shaping the cylindrical part of a suspended insulator with a cylinder, which can be manufactured without causing any breakage by reducing the disturbance of the particle orientation within the cylindrical suspension insulator, and without the need for finishing the inner part of the hole after drying. It has been completely destroyed. (Means for Solving the Problems) The present invention, which has been made to solve the above-mentioned problems, provides a lower mold in which a cylindrical core is set at a position corresponding to a cylindrical part forming a lightning arrester storage part, for example. Clay is poured into the core, and the clay is pressed using an upper mold having a cylindrical protrusion concentrically with the core to form a cylindrical part with a partition wall in the center integrally with the insulator body. It is characterized by cutting the inner surface of the cylindrical part along with the partition wall with a cylindrical blade, and then taking out the molded body together with the core from the lower mold. The present invention will be explained in more detail below along with an example of a method of forming a lightning arrester housing portion of a suspended type lightning arrester as shown in the drawings. (Example) In a preferred embodiment of the present invention, first, as shown in Fig. 1, clay (1) as a raw material is transferred to a rotating upper mold (2) of a baking iron type and a porous mold. The lower mold for hokekai shape (3) is used to create a strong shape. Next, the molded clay (1) is turned over while being adsorbed by the lower mold (3), and is placed into the porous lower mold (4) as shown in Figure 2. ．． As shown in the figure, the lower mold (4) has a recess (5) corresponding to the outer surface shape of the insulator, and a cylindrical core at a position corresponding to the cylindrical part that forms the lightning arrester storage part. (6)
is set. The core (6) is less than half the length of the lightning arrester housing and has a height that at least maintains a wall thickness that follows the shape of the cap of the insulator body, and its diameter is slightly larger than the inner diameter of the lightning arrester housing. Let it be small. The lower end of the core (6) preferably has a brim shape and has a slightly larger diameter. Next, place the clay (1) on the preliminary press shown in Figure 3 and the fourth
After going through the pre-Ol-kata process shown in the figure, the upper surface is gradually katami-sha, and then the process moves to the Hon-i-kata process shown in Figure 5. Here, press forming is performed using a Reiigata Kawakami die (7) whose shape corresponds to the inner surface shape of the insulator. This upper mold for the main shape (7) has a cylindrical protrusion (8) concentrically with the core (6) of the lower mold for the oval shape (4) described above. The length shall be less than half of the length of the required lightning arrester storage part, such that the gap formed between the opposing core (6) maintains a wall thickness slightly thicker than the wall thickness of the cap of the insulator body. ing. Lower mold for tc type (
When the clay (1) inside 4) is press-formed using this upper mold for this precept form (7), a partition wall (9) is formed in the center as shown in Figure 5.
) is molded integrally with the insulator body 01). Note that the upper die for main shaping (7) is also porous, and during press molding, the upper die for main shaping (7) and the lower die for shaping (
4) Reduce the pressure from inside to sharpen the air and obtain an accurate shape that matches the surface of each mold. After the formation, pressurized air is used to create a positive pressure inside the upper mold for main molding (7), and the upper mold for main molding (7) is air-blown.
7) is separated from the molded product, and the upper mold for this prescriptive form (7) is raised while the prescriptive product remains in the lower mold for prescriptive form (4). Next, as shown in FIG. 6, the partition wall (9) is removed by cutting the inner surface of the cylindrical portion OI that forms the lightning arrester storage portion using the rotating cylindrical blade 02+. The diameter of the cylindrical blade 021 is slightly larger than the diameter of the pressed cylindrical part O1, and the inner surface of the cylindrical part OI is slightly cut, but the lower surface of the cylindrical blade 021 at the lowest position still has a diameter of 0.5 mm. Make sure that the clay of the size of a temple remains. In addition, the diameter of the cylindrical blade 021 is slightly larger than the diameter of the core (6) of the lower die (4), so the core (6) remains uncut and the partition wall (9) remains intact. It remains inside the cylindrical blade 021 in the cut state. Next, raise the cylindrical blade θ, bring the vacuum suction cup θ into close contact with the top surface of the molded product as shown in Figure 7, and place the pre-shaped product into the lower mold for shaping (
Remove from 4) while blowing with air. At this time, the lower surface of the cylindrical part 0 (I) that forms the lightning arrester storage part is the core (6
), the molded product is covered by the core (6
) and is smoothly removed from the lower mold (4).
The core (6) together with the cut partition wall (9) is then removed downward from the cylindrical part 00, forming a penetrating cylindrical part 00.
This state is shown in Figures 9 and 10. Next, as shown in Fig. 8, the inner surface of the cylindrical part 0ω, which forms the lightning arrester housing section through which it has passed, is finished by a rotating trowel 04. As shown in the figure, the trowel has a cylindrical shape with many shallow grooves 051 in the vertical direction, and is rotated while supplying oil into these grooves to obtain a smooth inner surface. Through the above steps, a suspended insulator integrally equipped with a cylindrical portion 0ω is formed. As described above, according to the method of the present invention, the cylindrical core (6) of the lower molding mold (4) and the cylindrical protrusion (8) of the upper mold for cutting (7) form a mold in the central part. The thin cylindrical part θω remains with the partition wall (9) slightly thicker than the insulator cap part.
will be punished. Therefore, the flow of clay in this part is illustrated as shown in Fig. 11, and the flow of clay near the surface of the vertically protruding part of the cylindrical part 0ω is almost parallel to the surface. Therefore, even when the inner surface of the cylindrical portion aω is cut by the cylindrical blade θ, the flow of clay is only slightly cut by the cylindrical blade 02). On the other hand, when using the lower die (4) without the core (6), the cylindrical part OI becomes thicker, resulting in a flow of clay as shown in Fig. 12, and the cylindrical blade When the inner surface of the cylindrical portion Ol is cut according to (12), the flow of clay is cut off. As a result, according to the conventional method, cuts are likely to occur on the inner surface of the cylindrical portion QOI, but according to the present invention, cuts on the inner surface of the lightning arrester storage section (toward) can be almost completely prevented. In addition, according to the present invention, the flow of clay near the cylindrical surface can be made almost parallel to the surface.
It is possible to obtain a cylindrical portion θω with high strength without causing disturbances in particle orientation that would cause clay to form in the inside. (Effects of the Invention) As is clear from the above explanation, according to the present invention, a suspended insulator having an integral cylindrical portion can be produced without causing cuts in the hole, and in drying the inner cavity of the hole. It can be manufactured without the need for subsequent finishing processing. Furthermore, according to the present invention, the molded product after drilling can be taken out from the lower mold using the core with a vacuum suction cup, so that the drilling process can be performed inside the lower mold, There is no need to drill holes in the cylindrical part during post-processing after drying as in the conventional method. Therefore, the present invention has great potential to contribute to the development of industry as a method for forming the cylindrical portion of a cylindrical suspension insulator that solves the conventional problems.

[Brief explanation of drawings]

FIGS. 1 to 8 are all cross-sectional views explaining the process of the embodiment of the present invention, FIGS. 9 and 10 are partially enlarged cross-sectional views explaining the process of making holes in the cylindrical part, and FIG. is a cross-sectional view showing the flow of clay in the cylindrical part before drilling, Figure 12 is a cross-sectional view showing the flow of clay in the same part shaped by the conventional method, and Figure 13 is the conventional shape. FIG. 3 is a cross-sectional view showing the method.

Claims (1)

[Claims] The clay (1) is put into the lower mold (4) in which a cylindrical core (6) is set in the position corresponding to the cylindrical part (10), and the cylindrical mold is placed concentrically with this core (6). The upper mold (
7), this clay (1) is press-molded to form a cylindrical part (10) having a partition wall (9) in the center integrally with the insulator body, and the inner surface of the cylindrical part (10) is formed by a cylindrical blade (12). A method for forming a cylindrical part of a suspended insulator with a cylinder, characterized in that the molded body is cut together with the partition wall (9) and the molded body is taken out from the lower mold (4) together with the core (6).