JP2000283145A - Ball joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increasing of a rotary torque by positioning an inner circumferential surface spherical core of a bearing before assembly on an opening side from an outer peripheral surface spherical core, setting an inner circumferential surface curvature larger than an outer peripheral surface curvature, and gradually thinning its wall thickness from a bottom part toward the opening port. SOLUTION: In a bearing 5, a spherical core O of an inner circumferential surface 5a and a spherical core O' of an outer peripheral surface 5b are set on the same line of an axial direction in a condition before assembly, and the spherical core O is positioned on an opening port 6 side from the spherical core O'. A curvature of the inner circumferential surface 5a is set larger than a curvature of the outer peripheral surface 5b, an wall thickness of the bearing 5 is most thickened in the vicinity of a bottom part 7, and it is gradually thinned toward the opening port 6. In pressure applied on a bearing 5 by a load of an axial direction of a joint, pressure P is largest in the vicinity of the bottom part 7, and it is gradually small toward the opening port 6. The pressure P is increased in the vicinity of a tip end part of the spherical head part 4 where there is a few ratio when a spherical head part 4 is brought into contact with the bearing 5 and an interference of a rotary torque is small. On the other hand, pressure P' is decreased in the vicinity of the equator part of the spherical head part 4 where there is much ratios and the influence is large. It is thus possible to suppress increasing of the rotary torque.

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 for, for example, a vehicle suspension system.

[0002]

2. Description of the Related Art Conventionally, ball joints have been frequently used for connecting parts of a suspension system of an automobile or the like. Such ball joints include those as shown in FIG. A ball joint 101 shown in FIG. 4 has a spherical ball head 104 and a handle 1 protruding from the ball head 104.
The ball stud 102 and the ball head 104 of the ball stud 102 are swingably and rotatably held, and an opening 106 is formed on one side and a bottom 107 is formed on the other side. Bearing 105 made of synthetic resin having a substantially hemispherical shape, and an opening 1
A housing 109 having a substantially cup-like shape having an outer peripheral surface 10 and one end face being applied to the peripheral convex portion 108 of the bearing 105, and a flange portion 111 a formed in a peripheral shape on the outer peripheral surface is caulked and fixed to the opening 110 of the housing 109. Ring 111 and a small opening 113 in which a reinforcing ring 115 having an L-shaped cross section is embedded are mounted on the outer periphery of the handle portion 103 of the ball stud 102, a large opening 114 is mounted on the outer periphery of the ring 111, and an annular circlip 116 is formed. It consisted of the dust cover 112 fitted. The inner diameter of the bearing 105 of the ball joint 101 is slightly smaller than the outer diameter of the ball head 104 of the ball stud 102. The inner peripheral shape of the housing 109 is substantially the same as the outer peripheral shape of the bearing 105.

As shown in FIG. 6, the bearing 105 of the ball joint 101 is formed such that the sphere O of the inner peripheral surface 105a and the sphere O 'of the outer peripheral surface 105b coincide with each other before assembly. And the thickness is almost the same over the entire circumference.

[0004]

The ball joint 101 having the bearing 105 having the above-described structure is substantially evenly placed on the ball head 104 of the ball stud 102 when an axial load is applied, as shown in FIG. , The pressure from the bearing 105 is applied, and the torque increases. Particularly with respect to the rotational torque, the ball head 104 is
When the pressure P ′ near the equator, which has a large contact ratio with 5, increases, the rotational torque increases more remarkably than the pressure P near the tip of the ball head 104 increases. Therefore, there has been a problem that the rotational torque becomes larger than a desired value.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a ball joint capable of suppressing an increase in rotational torque.

[0006]

The configuration of the present invention is as follows.

A ball stud having a spherical ball head and a handle protruding from the ball head; In a ball joint composed of a bearing having a bottom portion and a housing including the bearing and having an opening on one side, the bearing has a center of the inner peripheral surface which is coaxial with a center of the outer peripheral surface in the axial direction before assembly. , And the curvature of the inner peripheral surface is larger than the curvature of the outer peripheral surface, and the thickness of the bearing gradually decreases from the bottom toward the opening.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a ball joint 1 according to an embodiment of the present invention. This ball joint 1
Is a spherical ball head 4 and a handle 3 protruding from the ball head 4
And a ball head 4 of the ball stud 2 which swingably and rotatably surrounds, has an opening 6 on one side and a bottom 7 on the other side, and has a circumferential projection 8 formed on the outer peripheral surface. A substantially hemispherical bearing 5 made of synthetic resin, and a substantially cup-shaped housing 9 containing the bearing 5 and having an opening 10 on one side.
One end face is applied to the circumferential convex portion 8 of the bearing 5, and a flange portion 11 a formed circumferentially on the outer circumferential surface is caulked and fixed to the opening 10 of the housing 9 to prevent the bearing 5 from coming off. A ring 11 and a small opening 13 in which a reinforcing ring 15 having an L-shaped cross section is embedded are mounted around the handle 3 of the ball stud 2, and a large opening 14 is mounted around the ring 11 by an annular circlip 16. It is composed of a dust cover 12. The inner diameter of the bearing 5 of the ball joint 1 is formed slightly smaller than the outer diameter of the ball head 4 of the ball stud 2. Housing 9
Is substantially the same as the outer peripheral shape of the bearing 5.

[0010] The bearing 5 of the ball joint 1
In the state before assembly, as shown in FIG. 3, the spherical center O of the inner peripheral surface 5a and the spherical center O 'of the outer peripheral surface 5b are located on the same line in the axial direction as shown in FIG. Are located closer to the bearing 5 opening 6 than the spherical center O 'of the outer peripheral surface 5b. The curvature of the inner peripheral surface 5a is larger than the curvature of the outer peripheral surface 5b, and the thickness of the bearing 5 is thickest near the bottom 7 of the bearing 5 and is gradually reduced toward the opening 6 of the bearing 5. Is formed. When the ball head 4 of the ball stud 2 is press-fitted into the bearing 5 through the bearing 5 opening 6 at the time of assembling the ball joint, the inner diameter of the bearing 5 is smaller than the diameter of the ball head 4. The diameter is increased to the same diameter as the diameter. At this time, the interference is large near the bottom 7 of the bearing 5, and the interference is reduced toward the opening 6.

When an axial load is applied to the ball joint 1 having the bearing 5 configured as described above, pressure is applied to the ball head 4 of the ball stud 2 from the bearing 5. At this time, the pressure applied to the bearing 5 is as shown in FIG.
As shown in the figure, the pressure P generated near the bottom 7 of the bearing 5 is the largest, and gradually decreases toward the opening 6. Therefore, the ratio of the ball head 4 of the ball stud 2 in contact with the bearing 5 is small, so that the influence of the rotational torque is small, the pressure P from the bearing 5 near the tip of the ball head 4 is large, and the contact ratio is large. Pressure P from the bearing 5 near the equator of the ball head 4 which greatly affects the torque
'Can be reduced.

[0012]

As described above, according to the present invention, a ball stud having a spherical ball head and a handle protruding from the ball head is provided, and the ball head of the ball stud is swingably and rotatably wrapped. In a ball joint comprising a bearing having an opening on one side and a bottom on the side opposite to the opening, and a housing containing the bearing and having an opening on the other side, the bearing has a ball on an inner peripheral surface in a state before assembly. The core is located on the bearing opening side on the same line in the axial direction from the spherical center of the outer peripheral surface, and the curvature of the inner peripheral surface is formed larger than the curvature of the outer peripheral surface, and the thickness of the bearing gradually increases from the bottom toward the opening. Since the ball joint becomes thinner, when the axial load is applied to the ball joint, the pressure that the ball head of the ball stud receives from the bearing is the largest pressure generated near the bottom of the bearing,
It becomes smaller gradually toward the opening. Therefore, the ball stud receives a large amount of pressure from the bearing near the tip of the ball head, which has a small effect on the rotational torque, and receives a large amount of contact from the bearing near the equator of the ball head, which has a large effect on the rotational torque. Since the pressure can be reduced, an increase in rotational torque can be suppressed. Also,
The ball joint requires a predetermined amount of torque. However, in the ball joint of the present invention, since the spherical center on the inner peripheral surface and the spherical center on the outer peripheral surface of the bearing are located on the same line in the axial direction, the wall thickness is large. Can be adjusted in a well-balanced manner, and a desired rotational torque can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a ball joint according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of a ball joint according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a ball joint bearing according to an embodiment of the present invention.

FIG. 4 is a partial sectional view showing a conventional ball joint.

FIG. 5 is an enlarged view of a main part of a conventional ball joint.

FIG. 6 is a sectional view showing a conventional ball joint bearing.

[Explanation of symbols]

 2 Ball stud 3 Handle 4 Ball head 5 Bearing 5a Inner peripheral surface 5b Outer peripheral surface 6 (Bearing) Opening 7 (Bearing) Bottom 9 Housing 10 (Housing) Opening O (Inner peripheral surface) Core O '(Outer peripheral surface) Sphere

Claims (1)

[Claims] 1. A ball stud (2) having a spherical ball head (4) and a handle (3) projecting from the ball head (4).
And a bearing (5) having a ball head (4) of the ball stud (2) swingably and rotatably and having an opening (6) on one side and a bottom (7) on the side opposite to the opening side. In a ball joint comprising a housing (9) including the bearing (5) and having an opening (10) in one side, the bearing (5) has a spherical center of an inner peripheral surface (5a) before being assembled. (O) is located on the bearing (5) opening (6) side on the same axial line as the spherical center (O ′) of the outer peripheral surface (5b), and the curvature of the inner peripheral surface (5a) is the outer peripheral surface (5b). A ball joint characterized in that the thickness of the bearing (5) is gradually reduced from the bottom (7) toward the opening (6).