JPH08128438A - Ball joint - Google Patents

Abstract

PURPOSE: To enable finishing only by forging without requiring the high sphericity and surface roughness for a ball center part by covering the outer spherical surface with a sliding member made of synthetic resin, in a spherical head part of a ball stud. CONSTITUTION: In a ball joint 1, a ball stud 2 composed of a spherical ball head part 4 and a handle part 3 projecting from the ball head part 4 is housed into a sheet metal made cylindrical housing 6. In the ball stud 2, a spherical head part 4 constituted by covering a spherical center part 4a integrally formed with the handle part 3, and a peripheral projecting part 4c formed on the outer periphery near the equator of the spherical center part 4a with a sliding member 4b made of synthetic resin. In the ball joint 1, the ball stud 2 is oscillated and rotated between the spherical head part 4 outer periphery of the ball stud 2, namely, the outer periphery of the sliding member 4b and an inner spherical surface 9 of the housing 6. In this ball stud 2, since the high sphericity and surface roughness are not required for the spherical center part, the spherical center part 4a can be finished only by forging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball joint used in, for example, a suspension system or a steering system of an automobile.

[0002]

2. Description of the Related Art Conventionally, a ball joint used in a connecting portion of a suspension system or a steering system of an automobile has a ball stud consisting of a spherical ball head and a handle protruding from the ball head, and a ball stud. Of the ball head of the ball stud and the inner spherical surface of the bearing. It was rocking and swinging between.

There are many such ball joints such as Japanese Utility Model Laid-Open No. 5-71544, Japanese Patent Laid-Open No. 5-34614, and Japanese Patent Laid-Open No. 6-17429.

[0004]

Since the ball joint is pivotally rotated between the outer spherical surface of the ball head of the ball stud and the inner spherical surface of the bearing, the ball joint has a high true surface. Sphere and surface roughness are required. Here, since the bearing is formed by injection molding in which a synthetic resin is injected into a mold defining a desired shape, a bearing having an inner spherical surface with high sphericity and surface roughness is obtained by increasing the precision of the mold. Can be formed.

On the other hand, the ball stud, as shown in FIG. 6, is successively formed by continuous forging from a rod-shaped cylindrical material 21 ((a) in FIG. 6). First, a preform 31 ((b) in FIG. 6) provided with a handle 33 is formed from the columnar material 21, and subsequently, an end portion on the opposite side of the handle 33 is set up and a spare ball head 44 is installed. The forged stud 51 (FIG. 6D) is formed by molding the provided intermediate molded product 41 (FIG. 6C) and finally further installing the spare ball head 44 to provide the spherical spherical center 4a. Had been molded. It should be noted that when the ball-centered portion 4a is installed, the extra thickness flows circumferentially around the ball-cored portion 4a to form the circumferential protrusions 4c, and thereafter, the circumferential protrusions 4c are removed by cutting. At the same time, in order to obtain the desired sphericity and surface roughness, the spherical center portion 4a must be finished by spherical rolling, which may increase the number of manufacturing processes and increase the cost.

Therefore, it has been attempted to finish the ball stud only by forging, but it has been difficult to finish the ball head which requires high sphericity and surface roughness.

Therefore, an object of the present invention is to provide a ball joint that solves the above problems.

[0008]

The structure of the ball joint of the present invention is shown below.

In a ball joint provided with a ball stud consisting of a spherical ball head and a handle portion projecting from the ball head, and a housing holding the ball head of the ball stud, the ball head of the ball stud is The outer spherical surface is covered with a sliding member made of synthetic resin.

[0010]

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

FIG. 4 shows a ball joint 1 according to an embodiment of the present invention, and 2 is a ball stud having a spherical ball head 4 and a stem 3 protruding from the ball head 4. Reference numeral 6 denotes a cylindrical housing made of sheet metal, which has an inner spherical surface 9 having substantially the same curvature as the ball head 4 of the ball stud 2 on its inner periphery, and the boot mounting portion 7 at one axial end and the boot mounting portion 7 at the other end. Caulking part 8
Have. An arm 12 having a support portion 13 for supporting the housing 6 is mounted on the outer periphery of the housing 6, and a plug 10 for closing the housing 6 is caulked and fixed to the inner periphery of the caulking portion 8 of the housing 6. Reference numeral 14 is a boot made of a rubber elastic body, and one end small opening 15 is a handle 3 of the ball stud 2.
It is attached to the outer periphery, and the other end large opening 16 is attached to the boot attaching portion 7 of the housing 6.

The ball stud 2 is, as shown in FIG.
By covering the spherical center 4a formed integrally with the handle 3 and the circumferential projection 4c formed on the outer periphery of the center 4a near the equator with the sliding member 4b made of synthetic resin. Ball head 4
Is configured. Therefore, in the ball joint 1, as shown in FIG. 4, the ball stud 2 swings and rotates between the outer circumference of the ball head 4 of the ball stud 2, that is, the outer circumference of the sliding member 4b and the inner spherical surface 9 of the housing 6.

Next, a method of manufacturing the ball joint 1 will be described.

First, a method of manufacturing the ball stud 2 will be described. As shown in FIG. 6, a preform 31 (FIG. 6B) in which a handle 33 is provided from a columnar material 21 (FIG. 6A). ) Is formed, and then the intermediate molded product 41 ((c) in FIG. 6) in which the end portion on the opposite side of the handle 33 is set up and the spare ball head 44 is formed, and finally the spare ball head is formed. The portion 44 is further installed to form a forged stud 51 ((d) in FIG. 6) provided with the spherical center portion 4a.

Here, from the intermediate molded product 41 to the forged stud 5
The forging process for molding 1 will be described with reference to FIG.

In the figure, the left half shows the state before forging and the right half shows the state after forging. The forging device 61 includes an upper mold 71 that can be raised and lowered, a lower mold 81 that has a mold engraved portion 83 and a knockout hole 84 to which a knockout pin 85 is to be mounted, and the lower part of the upper mold 71 and the lower mold 8 that face each other.
1. A hemispherical molding part 7 in which the spherical center part 4a is to be molded in the upper part
2, 82 are provided.

The forging stud 5 is manufactured by the forging device 61.
In the case of molding No. 1, first, as shown in the left half part of FIG.
As shown in the right half of FIG. 7, the upper die 71 is lowered and the forged stud 51 is formed by forging in the spherical center forming space formed of the hemispherical forming portions 72 and 82.

Subsequently, in a not-shown injection process, a sliding member 4b made of synthetic resin is spherically attached to the outer circumference of the spherical center portion 4a, and the manufacturing process of the ball stud 2 is completed. The movement of the sliding member 4b can be restricted by the circumferential convex portion 4c.

Further, the assembly of the ball joint 1 will be described in order. As shown in FIG. 1, an inner spherical surface 9 having substantially the same curvature as the ball head 4 of the ball stud 2 is previously formed on the inner periphery by sheet metal forming. An arm 12 having a cylindrical support portion 13 is attached to the outer periphery of a housing 6 having a caulking portion 8 to which a plug 10 can be attached at one end in the axial direction. Then, the end portion 7a of the housing 6 on the side opposite to the caulking portion is caulked to the outer peripheral side,
As shown in FIG. 3, the boot mounting portion 7 is molded, and thereafter, the spherical head portion 4 of the ball stud 2 is held on the inner spherical surface 9 of the housing 6 and the handle portion 3 is projected from the inner circumference of the boot mounting portion 7 as shown in FIG. Further, the plug 10 is attached to the inner circumference of the caulking portion 8, and the caulking portion 8 is caulked as shown in FIG.
Fix 0. Finally, the small opening 15 of the boot 14 is mounted on the outer periphery of the handle 3 of the ball stud 2, and the large opening 16 is mounted on the boot mounting portion 7 of the housing 6 to complete the manufacture of the ball joint 1.

Therefore, in the ball joint 1 manufactured as described above, the sliding member 4b is mounted on the outer periphery of the ball-center portion 4a of the ball stud 2, so that the ball-center portion 4a has high sphericity and surface roughness. Since the degree is not required, the spherical center portion 4a can be finished only by forging.

Further, since the caulking portion 8 is formed at one end of the housing 6 and the boot mounting portion 7 is formed at the other end by sheet metal processing when the ball joint 1 is assembled, it is not necessary to separately process.

Although the sliding member 4b is injection-molded in the above embodiment, it may be separately molded and mounted on the outer circumference of the ball center portion 4a of the ball stud 2.

[0023]

As described above, according to the present invention, the ball stud having the spherical ball head and the handle protruding from the ball head and the housing for holding the ball head of the ball stud are provided. In a ball joint, since the outer spherical surface of the ball head of the ball stud is covered with a sliding member made of synthetic resin, high sphericity and surface roughness are not required in the ball center portion. Can be finished only by forging, and the subsequent cutting and spherical rolling of the ball center is unnecessary, and costs can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional plan view showing a first stage of a manufacturing process of a ball joint according to an embodiment of the present invention.

FIG. 2 is a sectional plan view showing a second step of the manufacturing process of the ball joint according to the embodiment of the present invention.

FIG. 3 is a sectional plan view showing a third step of the manufacturing process of the ball joint according to the embodiment of the present invention.

FIG. 4 is a sectional plan view showing a ball joint according to an embodiment of the present invention.

FIG. 5 is a sectional plan view showing a ball stud used in the ball joint according to the embodiment of the present invention.

FIG. 6 is a plan view showing a forging process for manufacturing a ball stud used for a ball joint.

FIG. 7 is a partial cross-sectional plan view showing a final step of forging for manufacturing a ball stud used for a ball joint, in which the left half part shows a state before molding and the right half part shows a state after molding.

[Explanation of symbols]

 2 ball stud 3 handle part 4 ball head 4b sliding member 6 housing 7 boot mounting part 8 caulking part 10 plug 14 boot

Claims (2)

[Claims] 1. A ball stud (2) comprising a spherical ball head (4) and a handle (3) protruding from the ball head (4).
And a housing (6) holding the ball head (4) of the ball stud (2), the ball head (4) of the ball stud (2) has a composite outer spherical surface. A ball joint characterized by being covered by a sliding member (4b) made of resin. 2. A plug (10) for closing the housing (6) at one axial end of the housing (6) made of sheet metal.
The ball joint according to claim 1, wherein a swaged portion (8) is formed and a boot mounting portion (7) for mounting the boot (14) is formed at the other end.