JPH0513741B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for cold forging a ball joint socket, in which a ball joint socket molding material is fitted into a closed mold and cold forged.

(Prior Art) Conventionally, there is a method of manufacturing a ball joint socket using a cold forging method as shown in FIG.

First, a molded material is formed in which a substantially spherical spherical portion 2 is integrally formed at the end of a stepped shaft portion 1 .

Next, as shown by the diagonal line, the upper die 3
The above-mentioned molding material is hermetically fitted into a mold 3 which can be divided into a die 3b and a die 3b below.

The upper and lower dies 3a, 3b have recesses 3aa, 3bb, each having a shape approximately equal to the outer surface of the stepped shaft portion 1, so that the stepped shaft portion 1 of the overlapping molding material can be fitted tightly therein. It is formed.

Further, the upper and lower dies 3a and 3b are provided with cylindrical hollow portions 3ac and 3bc that are large enough to fit the spherical portion 2 when stacked together.

Further, the upper and lower dies 3a, 3b have recessed step portions 3ad, 3bd formed at the peripheral end portions where the overlapping surfaces 4 intersect with the inner surfaces of the hollow portions 3ac, 3bc.

Then, with the molding material fitted into the mold 3 as shown in FIG.
Holes 7 and 8 are formed in the ball, and the ball portion 2 formed with the holes 7 and 8 is used as a socket portion into which a joint ball (not shown) is fitted.

During this punch molding, the surplus of the ball part 2 escapes into the recessed steps 3ad and 3bd, and a burr 9 is formed on the outer peripheral wall of the ball part 2 where the holes 7 and 8 are formed. Finish by removing by machining such as cutting.

(Problems to be Solved by the Invention) However, in the case of such a cold forging method for a ball joint, when punching is performed, surplus of the molding material remains as burrs on the outer periphery of the socket portion. This burr must be removed by machining or the like, which is complicated.

Further, as shown in FIG. 9, when looking at the flow figure of the socket part, the flow of the pattern was not regular, which caused problems in strength and moldability.

(Means for Solving the Problems) In view of these problems, the present invention provides a ball joint socket that can mold a ball joint socket with excellent strength and moldability, and does not generate burrs. The purpose is to provide a method for cold forging a socket, and in order to achieve this purpose, a molded material is formed by integrating a ball part and a shaft part for molding a socket part, and a joint is attached to this ball part. When punching the socket hole to fit the ball,
By punching the socket hole from one direction of the spherical part and molding a convex part with a volume equal to or slightly smaller than the hollow volume of the socket hole in the opposite part of the socket hole, the socket hole is punched from one direction. By allowing the surplus of molding material generated during molding to escape into the convex portion, it is possible to mold a ball joint with excellent moldability and strength, and we have developed a technology that eliminates the occurrence of burrs. Make it the main point.

(Example) An example according to the present invention will be described below with reference to the drawings.

First, in the molding material forming step, a molding material for molding a ball joint socket as shown in FIGS. 1 and 2 is made.

That is, a substantially spherical spherical part 12 to serve as a socket part is integrally formed at the end of a cylindrical stepped shaft 11. The first flat surface 12a is connected to the second flat surface 12b on the end surface horizontal to the axial direction of the shaft portion 11.
12c is formed.

In the next punching step, the ball portion 12 is sealed and fitted into a mold 13 as shown by diagonal lines in FIG. 3, and the ball portion 12 is punched using punches 14 and 15.

That is, the mold 13 has upper and lower dies 16a, 16b.
The recesses 16aa and 16aa have a shape approximately equal to the outer surface of the stepped shaft portion 11, so that the stepped shaft portion 11 of the molded material can be tightly fitted into the stepped shaft portion 16a when stacked on top of each other. 16ba is formed.

Further, the upper and lower dies 16a and 16b are provided with cylindrical hollow portions 16ab and 16bb that are large enough to fit the spherical portion 12 when stacked together.

Furthermore, the upper die 16a has a hollow part 16.
Hollow portions 16ac having a smaller diameter than ab are arranged in series almost coaxially.

Then, with the molding material fitted into the mold 13 as shown in FIG. 3, the socket hole 12 is formed in the ball part 12 by punching the ball part 12 with punches 14 and 15 inserted into the hollow parts 16ac and 16bb. At the same time, the convex portion 12e on the side of the hollow portion 16ac is provided in a protruding manner.

This convex portion 12e controls the insertion amount of the punch 14 into the hollow portion 16ac so that the volume is equal to or slightly smaller than the hollow volume of the socket hole 12d.

4 to 7 show the shape of the ball joint socket molded in this example, FIG. 4 is a front view of the ball joint socket molded in this example, and FIG. 5 is a convex portion 12e. 6 is a rear view seen from the side, FIG. 6 is a side view seen from the shaft portion 11 side, and FIG.
The figure is an explanatory diagram showing the strain state of the socket section.

According to this embodiment, as explained in FIG. 3, when the socket hole 12d is formed with the punch 15, the convex portion 12e is simultaneously formed, so that the surplus of the spherical portion 12 due to the socket hole 12d is used to form the protrusion 12e. Do not put undue stress on the molded material.
Therefore, as shown in FIG. 7, the flow lines representing the strain state of the socket portion become regular, and a ball joint with good moldability and excellent strength can be molded.

Further, since the surplus of the ball portion 12 due to the socket hole 12d escapes to the convex portion 12e, the inner circumferential wall of the socket hole can be molded with high accuracy, and there is no need to form burrs, so conventional burr removal work can be avoided. can be omitted to simplify the work.

In this embodiment, the socket hole 12d is formed as a stepped hole with different inner diameters, but the present invention is not limited to this, and there is no problem in forming a socket hole as a straight hole.

(Effects of the Invention) As explained above, according to the present invention, a socket hole is punch-molded in a molding material, and at the same time a convex portion having a volume equal to or slightly smaller than that of the socket hole is formed. , it is possible to mold a ball joint socket with good moldability and excellent strength, and since the surplus of the molding material escapes to the convex part during the punch molding, there is no need to form burrs, making it easy to manufacture. The process can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a front view of a molding material used in an embodiment of the present invention, Fig. 2 is a side view of Fig. 1, Fig. 3 is a sectional view explaining the forging method of the embodiment, and Fig. 4 is an embodiment. Figure 5 is a rear view of the molded ball joint, Figure 6 is a side view of the molded ball joint, and Figure 7 is a flow diagram of the strained state of the socket. FIG. 8 is a cross-sectional view illustrating a conventional forging method for a ball joint socket, and FIG. 9 is an explanatory diagram showing a strained state of a conventional ball joint socket using flow lines. 11: shaft portion, 12: sphere portion, 12d: socket hole, 12e: convex portion, 13: mold, 14, 15: punch, 16a: upper die, 16b: lower die,
16ab, 16bb, 16ac: Hollow part.

Claims (1)

[Claims] 1. In a cold forging method for a ball joint socket in which a molding material for a ball joint socket is fitted into a closed mold and then cold forged, a substantially spherical ball is formed at the end of the stepped shaft. integrally provided, a first flat surface is formed on an end surface of the sphere facing the axial direction of the shaft, and a second flat surface is formed on an end surface of the sphere parallel to the axial direction of the shaft. a molding material forming step, and a molding material forming step in which the molding material formed in the molding material forming step is fitted into the closed mold and the spherical portion is punched to form a socket hole in the spherical portion, and a hollow hole in the socket hole is formed. 1. A method for cold forging a ball joint socket, comprising a punching step of forming a convex portion having a volume equal to or slightly smaller than the socket hole at a portion opposite to the socket hole.