JPS6033840A - Method for forming hollow ball having recess on outside circumferential surface - Google Patents

Abstract

PURPOSE:To obtain inexpensively a uniform product in short forming time by forming a recess to the outside circumferential part of a cylindrical blank pipe, inserting a space member into said recess and forming the pipe to a spherical shape by pressing. CONSTITUTION:A blank pipe 10 formed by cutting a pipe material is inserted into a die press 16. The press 16 has a projecting part 11' forming a recess to the pipe 10. The lower die thereof is divided to a lower left die 13 and a lower right die 14 which are movable forward and backward in a horizontal direction and have receiving recessed 15 for forming the recess 12. The pipe 10 is pressed by an upper die 11 and the dies 13, 14, by which the recess 12 is formed. A space member 17 is inserted into the recess 12 and the pipe 10 is inserted into a die press 22 formed with semi-spherical recesses 20, 21 to an upper die 18 and a lower die 19 so as to face each other in such a way that the axis of the pipe 10 is positioned in a vertical direction. The pipe 10 is then formed to a spherical shape by the pressing force of both dies 18, 19 and the member 17 is removed. The hollow ball having the recess 12 on the outside circumferential surface is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a hollow ball having a concave portion on the outer peripheral surface by press forming from a cylindrical material tube.

Conventionally, methods for forming this type of hollow ball include cutting methods and casting methods. However, in the cutting method, as shown in Fig. 1(a), (b), and (c), a bar with a circular cross section is cut into appropriate dimensions (see Fig. 1(a)).
) After cutting, the outside is machine-cut (see figure (b)), and the inside is machine-cut (see figure (c)).
Since there are many parts to be cut, material is wasted, the machining time becomes long and the process becomes expensive, which is undesirable from a resource saving perspective, and the hollow balls are also heavy. In addition, in the casting method, Fig. 2(a)
(b) Material 2 melted in mold 1 as shown in (c)
The mold is poured ((a) in the same figure), and after it hardens, it is removed from the mold ((b) in the same figure), and the removed material is machined and finished, as shown in (c) in the same figure. In this casting method, cavities are likely to form due to gas bubbles, and there are many cases where defects are discovered after machining and result in a large amount of waste.

In addition, due to hot water washing, the wall thickness becomes larger than necessary, which is a waste of material, and the weight also increases.Furthermore, the machined surface is rough, so a large amount of machining allowance is required, which increases the machining time. There is.

In order to overcome the drawbacks of these cutting methods and casting methods, there is a method of making a hollow ball by press forming from a cylindrical material tube, but this method is shown in Figure 3 (a).
) As shown in (b) and (c), first cut the pipe material into appropriate dimensions to make a cylindrical raw material tube (see Figure (a)), and then cut this raw material tube into an upper mold and a lower mold, respectively, into hemispherical shapes. It is press-formed into a spherical shape using a press having a concave portion (Figure (b)), and the four parts 3 are formed on the outer peripheral surface by press-forming (
(C)) However, when this recess 3 is used as a fitting part for a stem, etc. for rotating a hollow ball, the recess 3 can only be formed relatively shallowly, so the contact area is small. Therefore, there is a drawback that the recessed portion 3 tends to settle quickly and has poor durability.

This invention was made in view of the above-mentioned circumstances, and its purpose is to first form a recess by press working on the outer periphery of a cylindrical material tube, insert a space member into the recess, and then form an upper mold. The material tube is formed into a spherical shape by a mold press in which four hemispherical parts are opposed to each other on the lower mold, and finally the space member is removed, all of the above-mentioned drawbacks of conventional mechanical cutting, casting, and press processing are eliminated. It is an object of the present invention to provide a method for molding a hollow ball having a recessed portion on its outer circumferential surface.

The present invention will be described in detail below based on the accompanying drawings.

4(a) to 4(e) are process schematic diagrams showing the method according to the present invention. First, in FIG. 4(a), a material pipe 10 made by cutting pipe material into appropriate dimensions is placed in an upper mold 11. It has a convex part 11' forming a concave part 12, which will be described later, and the lower mold is divided into a left lower mold 13 and a right lower mold 14, which can move forward and backward from each other in the horizontal direction (indicated by arrow A). , into a mold press 16 having a receiving recess 15 forming a recess 12 . Next, as shown in FIG. 6B, the material tube 1o is pressed by the upper mold 11 and the left and right lower molds 13, 14 to form the recess 12 described above. And as shown in the same figure (c),
A space member 17 capable of maintaining the shape of the recess 12 is inserted into the recess 12 formed in the material tube 1o, and hemispherical recesses 20 and 21 are formed in the upper mold 18 and the lower mold 19, respectively, so as to face each other. The material tube 1o is inserted into the mold press 22 so that the cylindrical axis of the material tube 1o is in the vertical direction.

Next, the material tube 1o is formed into a spherical shape by the pressing force of both the upper and lower molds 18 and 19 of the mold press 22. Finally, the space member 17 is removed from the recess 12 to form a hollow ball having the recess 12 on the outer peripheral surface as shown in FIG. 2(e).

Although the method according to the present invention is as described above, since it is press molding, the molding time is shorter, it is cheaper, and 1
The surface texture is clean, there is less finishing allowance, a uniform product can be obtained, and precision can be improved. In addition, the wall thickness can be made thinner, so there is no waste of material.

Furthermore, unlike casting, there are no cavities, and the quality can be improved.

Its utility value is remarkable.

[Brief explanation of the drawing]

Figures 1 (a) to (c), Figures 2 (a) to (c), and Figures 3 (a) to (c) are process schematic diagrams showing conventional mechanical cutting, casting, and press working methods, respectively. , Figure 4 (
Figures a) to (e) are process schematic diagrams illustrating the method according to the invention. In the drawings, 10 material tube 12 recess 17 space member 18.19 upper and lower molds 20.21 hemispherical recess 22 mold press. Figure 1 (a) (b) Figure 2 Figure 3 (a) (b) (C) (c)

Claims (1)

[Claims] The above-mentioned ambidextrous mold press in which four parts are formed by press molding on the outer peripheral surface of a cylindrical material tube, and the material tube with these recesses is formed with hemispherical recesses facing each other in the upper mold and the lower mold. The cylindrical shaft is inserted into the spherical recess in the vertical direction, and a space member capable of maintaining the shape of the recess is inserted into the recess on the outer peripheral surface of the material tube, and then inserted by the pressing force of both molds. A method for forming a hollow ball having a concave portion on an outer circumferential surface, characterized in that the material tube is processed into a spherical shape, and the space member is removed after the material tube is processed into a spherical shape.