JPH0621670B2 - Ball valve ball molding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a ball used as a valve element in a ball valve for opening / closing and switching a fluid circuit.

[Conventional technology]

2. Description of the Related Art Conventionally, in the manufacture of balls used in a ball valve as shown in FIG. 2, it has been generally accepted that a casting operation by cutting operation is used. Of these, when cutting work, as shown in Fig. 3 (a) (b) (c), a bar a (circular cross-section a) cut into appropriate dimensions (Fig. (A)) is mechanically cut. Then, a spherical body b is formed (FIG. 2B), and an internal through hole c is formed by mechanical cutting (FIG. 2C). In the case of casting work, as shown in Fig. 4 (a) (b) (c),
The melted material e is poured into the mold d (Fig. (A)), after solidification, the cast product f is taken out of the mold (Fig. (B)), and the cast product taken out is machined to form the product ball. g. In addition to the above, a method of making a ball from a pipe by pressing work has also been proposed. As shown in Figs. 5 (a) (b) (c), first, the pipe material is cut into appropriate dimensions. To form a cylindrical material tube h (Fig. (A)), and the material tube h is press-formed into a spherical body i by a press machine having a hemispherical recess in each of the upper mold and the lower mold (see the same figure (Fig. b)),
Lastly, the outer peripheral portion is formed by punching out a recess j (see FIG.
(c)).

[Problems to be Solved by the Invention]

In the above-mentioned prior art, in the case of cutting work, not only the material is wasted due to the large number of cut portions, but also the processing time becomes long or expensive, which is not preferable from the viewpoint of resource saving and the finished ball. It was too heavy. Further, in the case of casting work, cavities due to air bubbles such as gas are likely to be formed, and such cavities are often found as defective after being machined, which is extremely uneconomical. Also, due to the flow of hot water, the wall becomes thicker than necessary, which is not only wasteful in terms of material, but also increases the weight,
Since the machined surface is rough, it requires a large amount of machining allowance, resulting in a long processing time. Furthermore, in the case of press work, due to the wall thickness of the pipe, the recess used as the fitting part of the stem must be relatively thin, and the area per stem becomes small, and the recess of the recess does not occur. The difficulty was that it was poor in durability quickly.

[Means for Solving the Problems]

This invention forms a concave portion for fitting a pulp shaft into the outer peripheral surface of the center of a material pipe made by cutting a pipe material to an appropriate size, and then takes out the material pipe from the mold press to obtain an upper die. Insert the material pipe into the die press formed so as to face each of the lower molds so as to face each other with the hemispherical recesses, and then insert the material pipe so that the cylinder axis of the material pipe is in the vertical direction. The present invention proposes a ball valve ball forming method characterized in that the material tube is formed into a spherical body by the pressing force.

[Action]

In the method of the present invention, after forming a concave portion for fitting a valve shaft by a die press on a central outer peripheral surface of a raw material pipe made of a pipe material, an upper die is arranged so that a cylinder axis of the raw material pipe is in a vertical direction. And the lower mold are inserted into a mold press formed so as to face each other with hemispherical recesses, and the material tube is formed into a spherical body in both upper and lower molds of the mold press.

〔Example〕

Hereinafter, the method of the present invention will be described in detail with reference to the accompanying drawings.

1 (a) to 1 (e) are schematic views of a process for manufacturing a valve for a ball valve. First, FIG. 1 (a) shows a material pipe 1 made by cutting a pipe material to an appropriate size. The mold 2 has a convex portion 4 forming a recessed portion 3 for fitting a valve shaft, which will be described later, and the lower mold is divided into a left lower mold 5 and a right lower mold 6 into left and right parts, which can move back and forth in the horizontal direction. Along with (indicated by arrow A),
Mold press 8 having a receiving concave portion 7 forming the concave portion 3
Insert inside. Next, as shown in FIG. 1 (b), the material pipe 1 is pressed by the upper mold 2 and the left and right lower molds 5 and 6 to form the above-mentioned concave portion 3 for fitting the valve shaft. Then, as shown in FIG. 1 (c), a space member 9 capable of maintaining the shape of the concave portion 3 is inserted into the concave portion 3 formed in the material tube 1, and the upper mold 10 and the lower mold 11 are separated from each other. Hemispherical recess 1 for each
The material tube 1 is inserted into a die press 14 formed so as to face the reference numerals 2 and 13 such that the cylinder axis of the material tube 1 is in the vertical direction. Next, the upper and lower dies 10, 1 of the die press 14
The material tube 1 is formed into a spherical shape by the pressing force of 1. Then, finally, the space member 9 is removed from the recessed portion 3 and is shown in FIG.
A hollow ball having a concave portion 3 on the outer peripheral surface shown in (e) is formed.

〔The invention's effect〕

Since the ball for a ball valve manufactured by the method of the present invention is manufactured by press molding, the molding time is short, the cost is low, the surface skin is clean, the finishing allowance is small, and a uniform product is obtained. As a result, the accuracy can be improved. Further, the wall thickness can be reduced, and the material is not wasted. Further, it has an effect that it is possible to improve quality without forming a cavity unlike casting, and its utility value is remarkable.

[Brief description of drawings]

1 (a) to 1 (e) are schematic views showing the order of forming balls by the method of the present invention, FIG. 2 is a sectional view of a ball valve in which the balls of the present invention are used, and FIG. 3 (a). ) Or
(c), FIGS. 4 (a) to (c), and FIGS. 5 (a) to (c) are process schematic diagrams showing conventional methods by mechanical cutting, casting, and pressing. In the figure, 1 ... Material tube 2 ... Recessed part 8 ... Mold press 10, 11 ... Upper and lower molds 12, 13 ... Hemispherical recess 14 ... Mold press.

Claims (1)

[Claims] 1. After forming a concave portion for fitting a pulp shaft into a central outer peripheral surface of a raw material pipe formed by cutting a pipe material to an appropriate size, the raw material pipe is taken out from the die press and Insert the material tube into the die press formed so that the hemispherical recesses face each other in the die and the lower die so that the cylinder axis of the material tube is in the vertical direction, and then insert the material tube into the die press machine. A method for molding a ball for a ball valve, characterized in that the material tube is formed into a spherical body by the pressing force of both molds.