JPS61228116A - Ball joint - Google Patents

Abstract

PURPOSE:To prevent a boot from being cracked, by expanding an increase of a radius of curvature in the vicinity of the peripheral end part of a spiral cir-clip and eliminating a small curvature part and a clearance in the vicinity of the peripheral end part. CONSTITUTION:A spiral cir-clip 10 forms in the vicinity of its peripheral end part 21 a large radius of curvature part 23 forming an increase of a radius of curvature in the vicinity of the peripheral end part 21 larger than the increase of that in an intermediate part. The spiral cir-clip 10, spreading its internal contour in the free condition, is mounted to a boot groove 9. Consequently, the spiral cir-clip 10 tightens a boot large opening edge part 8 to a peripheral groove 15 of socket 11. Accordingly, the spiral cir-clip, when it is mounted, generates no small curvature part and clearance in the vicinity of the peripheral end part of the cir-clip, preventing a boot from being cracked.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to ball joints used in automobile steering systems, suspension systems, and other link mechanisms, and is used to securely attach a boot to a socket or the like that is the main body of the pole joint. This invention relates to a ball joint in which a spiral circlip that spirals on a plane is attached to the outer periphery of the boot opening edge in order to achieve this.

Prior Art This type of ball joint is disclosed in Japanese Patent Application No. 59-45086 filed by the same applicant as the present application.

Problems to be Solved by the Invention When the spiral circlip 10a as shown in FIG. 5 is attached to the predetermined position of the ball joint 1 as shown in FIG. 4 and FIG. The circlip 10a has approximately two turns when installed.

In this way, when the spiral circlip 10a is designed to have approximately two turns when installed, a small radius of curvature portion 25 and a gap 24 are generated near the outer peripheral end portion 21a of the circlip due to the installation.

Since this small radius of curvature portion 25 protrudes toward the outer periphery in the radial direction as shown in FIG. 4, the deformation of the boot 5 caused by the rocking of the ball stud 2 causes unnecessary friction with the boot body 6.

As a result, cracks occur in the friction portion 17a of the boot body 6,
Further, as shown in FIG. 7, there is a problem in that the outer circumferential end portion 21 of the circlip comes off from the groove, which causes the boot function to be lost.

Means for Solving the Problem The amount of increase in the radius of curvature near the outer peripheral end of the spiral circlip when it is free is made larger than the amount of increase in the middle portion.

Function: Small curvature and gaps do not occur near the outer edge when the spiral circlip is installed.

Embodiments Hereinafter, the configuration of embodiments of the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of a pole joint 1 according to the present invention. In the figure, reference numeral 11 denotes a socket having a bearing member 12 on its inner periphery.

A ball stud 2 has a handle 3 and a spherical head at the tip of the handle, and the spherical head is supported by the inner spherical surface of the bearing member 12.

The socket 11 has openings at the top and bottom, and the large opening at the bottom is closed by press-fitting and fixing a closing plate 18 made of a disc spring covered with a rubber layer 14, and the other upper opening 16 allows the handle 3 of the ball stud 2 to protrude. At the same time, the space around the opening is shielded from the outside by the boot 5.

The boot 5 has an upper small opening edge 7 fitted into a predetermined position of the ball stud handle 3, and a lower large opening edge 8 fitted into the circumferential groove 15 of the socket 11.

An annular boot groove 9 that opens to the outer periphery in the radial direction is formed on the outer periphery of the lower large opening edge 8, and a spiral circlip 10 that swirls on a plane is attached to the groove 9.

The boot 5 is formed of a suitable synthetic rubber into a cylindrical shape having a thin cylindrical body portion 6 whose middle portion between the opening edges 7 and 8 bulges outward in the radial direction.

The spiral circlip 10 is designed in advance to have approximately two turns when installed.

The spiral circlip 10 is made of metal or other suitable material and is approximately
A large radius of curvature portion 22 is formed in the vicinity of the inner peripheral end portion 20 and has a large radius of curvature.

and the outer peripheral end 21 of the spiral circlip when it is free.
A large radius of curvature portion 23 is formed near the outer circumferential end portion 21 in which the amount of increase in the radius of curvature is larger than that of the intermediate portion.

The radius of curvature of the large radius of curvature portion 28 on the side of the outer peripheral end 21 is as follows:
The radius of curvature is equal to or slightly smaller than the radius of curvature near the outer peripheral end 21 assuming that the spiral circlip is normally and closely attached.

When installing the spiral circlip 10, the inner diameter of the circlip in the free state is expanded and the spiral circlip 10 is installed in the boot groove 9. This allows the spiral circlip 10 to tighten the large opening edge 8 of the boot into the circumferential groove 15 of the socket 11. Further, the vicinity of the outer circumferential end 21 of the spiral circlip 10 also becomes close to the inner circumferential side without creating a small radius of curvature, as shown in FIG.

Note that the present invention is not limited to the above-mentioned embodiments; the socket may be made of fiber-reinforced plastic, the socket bearing member may be integrally molded from the same material, or a circumferential groove into which the boot opening periphery is fitted may be formed in the bearing member. Alternatively, in order to eliminate the closing plate, a socket without an opening at the bottom may be used, or a 7-flange portion may be integrally formed on the outer periphery of the bottom of the bearing member and fitted into a groove provided on the inner periphery of the socket portion. Needless to say, it can be applied to structural pole shields.

Effects As described above, according to the present invention, when a spiral circlip is installed, a small curvature portion and a gap do not occur near the outer peripheral edge of the circlip, and therefore, cracks in the boot and separation of the spiral circlip are eliminated. This has the effect of facilitating stabilization of functions.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional plan view of a pole joint according to an embodiment of the present invention. FIG. 2 is a plan view of the spiral circlip attached to the ball cylinder in FIG. 1. Figure 3 shows ■-■ of Figure 1.
A sectional view showing a cross section. FIG. 4 is an explanatory cross-sectional plan view of a conventional ball joint. FIG. 5 is a plan view of the spiral circlip attached to the pole joint of FIG. 4. FIG. 6 is a sectional view taken along the line ■-■ in FIG. 4. FIG. 7 is a partial plan view taken in the direction of arrow 2 in FIG. 4. (Explanation of symbols) 1...Pole joint. 2...Ball stud. 3...Handle. 5...B
- Tsu. 8... Large opening edge. io・・・・・・
Swirl circlip. 11...Socket. 21...Outer peripheral end. 23...Large curvature radius part. j Figure 4 Figure 6

Claims (1)

[Claims] Protected by a boot 5 whose one end fits into the ball stud handle 3 and whose other end fits into the socket 11,
In a ball joint 1 in which a spiral circlip 10 that spirals on a plane is attached to the outer periphery of the large opening edge 8 of the boot 5, the outer peripheral end 2 of the spiral circlip when it is free.
A ball joint characterized in that the amount of increase in the radius of curvature near 1 is greater than the amount of increase in the middle portion.