JPH0683884B2 - Manufacturing method of ball studs for rack end ball joints - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ball stud for a rack end ball joint used in, for example, an automobile steering system.

2. Description of the Related Art In a conventional method for manufacturing a ball stud for a rack end ball joint, a sixth embodiment showing the same portion as part D in FIG.
As shown in the figure, in the preforming, the two-sided portion 10 of the rough material 101d
When the outer diameter of the head side 103d of 2d is 1A, the outer diameter of the handle side 104d of the two-sided portion 102d is 1C, and the shoulder 125 inner diameter of the ball stud main forming lower mold 124 is 1B, 1A = 1C <1B Then, the ball studs were main-formed.

1A = 1B = 1C is not preformed because the outer diameter of the handle 104d of the two-face 102d of the rough material 101d is the same as the inner diameter of the shoulder 125 of the ball stud main forming lower die 124. This is because the rough material 101d is inclined to fit into the lower mold 124 and easily fits therein.

Problems to be Solved by the Invention In the method of manufacturing a ball stud for a rack end ball joint as described above, 1A = 1C <1B, so during ball stud main molding, the two-sided portion 102d is a ball stud main molding bottom metal. The inner diameter of the shoulder 125 of the mold 124 can be easily passed.

However, since the volume of the rough material is insufficient, the ball stud main molding lower mold 124 is not filled with the rough material.

Therefore, as shown in FIG. 7, the width of the two-face portion 102e of the molded ball stud 101e is not completely expanded, and the thin portion 109e is generated. When the ball stud 101e is used for the ball joint, the two-face portion 102e is not formed. If you use a spanner, it may slip.

In order to completely stretch the width of the two-face portion 102e, the molding load must be increased, which causes a problem that the mold cannot withstand the load.

In order to solve this problem, in preforming, as shown in FIG. 8 showing the same portion as FIG.
When the outer diameter of the head side 203d of 2d is 2A, the outer diameter of the handle side 204d of the two-sided portion 202d is 2C, and the shoulder 225 inner diameter of the ball stud main molding lower mold 224 is 2B, 2A = 2C> 2B When the ball stud is main-formed, the end surface 208d of the rough material 201d hits the taper portion 226 of the ball-stud main-forming lower die 224, and then the two-face portion is formed.
When the 202d is extremely squeezed by the shoulder portion 225, the extra thickness flows to the end surface 208d and becomes a swelling 208d. Then, after the molding is completed, as shown in FIG. 9, the protrusion 210e remains on the end face 208e.

Therefore, after assembling to the ball joint, the end face 208e does not come into close contact with the end face of a counterpart such as a gear box that comes into contact with the end face 208e, and loosening occurs.

Means for Solving the Problems In preforming, the two-sided portion of the rough material is A, the outer diameter on the head side of the two-sided portion is A, the outer diameter on the handle side of the two-sided portion is C, and the ball stud main forming bottom metal When the shoulder inner diameter of the mold is B, the taper shape of A>B> C is formed, and the end surface is formed on the handle portion side of the two-faced portion.
After that, by ironing the two-sided part by main forming and pressing the end face against the end face of the two-sided part of the ball stud main forming lower mold,
The surfaces of the two surfaces are formed in parallel.

Function In the main forming, the tip of the rough material on the handle side of the two-sided part easily passes through the shoulder inner diameter of the ball stud main forming lower die, and then the two-sided rough material volume is squeezed through the shoulder inner diameter. Is gradually increased so that the head side of the two-sided part, which is larger than the inner diameter of the shoulder part, is continuously and smoothly ironed, and the head part of the rough material is pressed by the slide knockout pin and the ball stud main forming die. At the same time, the end surface of the rough material on the handle surface side of the two-sided portion is pressed against the end surface of the two-sided portion of the lower mold for the main molding of the ball stud. Therefore, the surplus near the radial center of the two sides of the rough material flows in the outer diameter direction after passing through the shoulder of the ball stud main forming lower die, and fills the space of the straight part of the ball stud main forming lower die. To do.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

The rough material 1d shown in FIG. 3 is a step of forming a small-diameter handle portion by forward extrusion on a cylindrical material having substantially the same diameter and substantially the same volume as the rough material 1d, and then installing the head slightly. The two-sided portion 2d and the head portion 6d are preformed after two pre-preforming steps (not shown) including the step of inserting.

The two-sided portion 2d is, as shown in FIG.
The outside diameter of the head side 3d of the two-sided portion 2d is A, the outside diameter of the handle side 4d is C,
In the next step, assuming that the inner diameter of the shoulder 25 of the lower mold 24 of the main molding of the ball stud is B, the molding is performed so that A>B> C. And 2
An end surface 8d is formed on the handle portion side 4d of the surface portion 2d.

Next, the rough material 1d that has been subjected to the above-mentioned preforming is main-formed.

In the main forming of the ball stud, first, as shown in the left half of FIG. 1, the rough material 1d is set in the mold engraving portion of the lower ball stud main forming mold 24. In the figure, 20 is a ball stud main mold upper mold, 21 and 28 are tightening rings, 22 is an upper mold, 23 is a slide knockout pin, 29 and 30 are lower molds, 31
Is a knockout pin. After setting the rough material 1d, as shown in the right half of FIG.
And slide knockout pin 23 to act on head 6d
Is set up in the axial direction to form the ball head 6e, and the two-sided portion 2d is ironed to make the tapered surfaces 5d and 5d parallel to each other.
Mold into e.

As mentioned above, the two-sided portion 2d and the ball stud main molding lower mold 24
Since the dimensional relationship with the shoulder portion 25 of A is B>C> C, during ironing, after the tip of the rough side 1d on the handle side easily passes the inside diameter of the shoulder portion 25, The two-sided portion 2d having a large diameter is continuously and smoothly rubbed to the head side 3d, and the end face 40 of the two-sided portion of the ball stud main forming lower mold 24 has the two-sided portion of the rough material.
The end face 8d formed on the 2d handle portion side 4d is pressed. As a result, as shown in the right half of FIG. 1, the excess thickness of the rough material 1d in the vicinity of the radial center of the two-face portion 2d flows in the outer radial direction, and the space for the straight portion 27 of the ball stud main forming lower mold 24 is reduced. Fills in.

Therefore, as shown in FIGS. 4 and 5, the surfaces 5e and 5e of the two-sided portion 2e of the molded ball stud 1e are parallel to each other, and
No flesh of 5e, 5e or swelling on the end face 8e occurs.

After the main molding, the unnecessary portion is cut to form a large-diameter flange portion having two surface portions, and the ball stud manufacturing is completed.

Effects As described above, according to the present invention, in the main forming, the tip of the rough material on the handle portion of the two-sided portion easily passes through the shoulder inner diameter of the ball stud main forming lower die and then passes through the shoulder inner diameter. Since the volume of rough material on the two-sided portion that is squeezed is gradually increased, the head side of the two-sided portion, which has a larger diameter than the shoulder inner diameter, can be continuously and smoothly ironed, and the head of the rough material can be slide knockout pin. Also, the upper surface of the ball stud main molding is pressed, and the end surface of the lower surface of the ball stud main molding is pressed against the end surface formed on the handle surface side of the two-sided rough material. Therefore, the surplus near the radial center of the two faces of the rough material,
After passing through the shoulder of the ball stud main forming lower mold, it flows in the outer diameter direction and fills the space of the straight part of the ball stud main forming lower mold, so that the two side parts can be completely stretched without lacking thickness. Also, no bulge is formed on the end face. Therefore, when this ball stud is used in a ball joint, it is possible to accurately apply a wrench to the two surface portions, and to closely join the end surface of a gear box or the like that abuts the end surface.

[Brief description of drawings]

FIG. 1 is a sectional view showing a step of forming a ball stud from a preformed rough material according to the present invention. FIG. 2 is an enlarged explanatory view of section D in FIG. FIG. 3 is a sectional view of a preformed rough material according to the present invention. FIG. 4 is a front view of the ball stud molded in the embodiment of the present invention. FIG. 5 is a sectional view taken along the line VV of FIG. 6 and 8 show a step of forming a ball stud from a preformed rough material by the conventional manufacturing method.
Explanatory drawing of the same part as a figure. 7 and 9 are front views of a ball stud formed by a conventional manufacturing method. (Explanation of symbols) 1d …… Rough material. 2d …… Two sides. 3d …… Head side. 4d …… The handle side. 5d ... surface. 24 …… Ball stud Main mold lower mold. 25 ... Shoulder. A: 3d outer diameter on the head side. B: 25 shoulder inner diameter. C: 4d outer diameter on the handle side.

Claims (1)

[Claims] 1. A method for manufacturing a ball stud having a large-diameter flange portion between a ball head and a tip of a shank portion, and the flange portion having a two-faced portion for spanner hanging, in a preliminary molding, a rough material is used. The two-sided portion 2d of 1d, the outer diameter of the head side 8d of the two-sided portion 2d is A, 2
When the outside diameter of the handle portion side 4d of the surface portion 2d is C and the inside diameter of the shoulder portion 25 of the ball stud main molding lower die 24 is B, the taper shape is A>B> C and the handle of the two surface portion 2d is used. The end face 8d is formed on the part side 4d, and then the two-face part 2d is ironed by main forming,
A method of manufacturing a ball stud for a rack end, characterized in that the end surface 8d is pressed against the end surface 40 of the two-sided portion of the ball stud main forming lower mold 24 to form the surfaces 5d and 5d of the two-sided portion in parallel. .