JPH0350134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ball joint used in automobile suspension systems, steering systems, and the like.

Conventional technology Ball joints for high loads are generally metal contacts with high frictional resistance, where metal-to-metal sliding contact is made.
For low-load applications, resin contacts with low frictional resistance, where metal and resin slide, are used. However, in order to save energy, it is desired to develop a ball joint that is not only smaller and lighter but also has low frictional resistance and can withstand high loads.

Therefore, the idea was to install a thin layer of resin bearing of about 0.2 to 0.9 mm on the high load bearing side of the sliding surface with the ball stud ball head to reduce friction and to reduce the amount of movement of the ball stud under load (lift). In addition, the inner wall surface of the housing is treated as an integral back metal, and a thin layer of resin bearing is placed in close contact with the hemispherical catch seat to withstand high loads.

Problems to be Solved by the Invention However, in this case, if the ball joint is used for an extremely long period of time, the thin resin layer will flow under load, stretch to the axial opening, and create a thinned part, as well as metal contact. There was a risk that it would happen.

An object of the present invention is to prevent flow of a resin bearing without increasing the thickness of the resin bearing more than necessary.

Means for Solving the Problem A conical conical seat is provided on the inner periphery adjacent to the opening of the housing, and a cylindrical seat is provided that is connected to the large diameter side of the conical seat and extends cylindrically in the axial direction of the housing. In addition, a shoulder portion is provided that is the thickest part near the intersection of the conical seat and the cylindrical seat, and an opening edge that tapers toward the opening of the housing and has a wedge-shaped cross section. A certain ball head receiving surface is a curved surface whose radius is larger than the radius of the ball head, and when viewed from approximately the center of the ball head,
Contact the ball head most strongly in the direction of the intersection between the conical seat and the cylindrical seat.

Function During normal use, the load transmitted to the bearing by the ball head of the ball stud is concentrated on the shoulder, which is the thick wall of the bearing, near the intersection of the conical seat and the cylindrical seat of the housing. Both sides of the shoulder have a wedge shape with an extremely thin wall thickness at the closest point between the seat and the ball head, so as the shoulder stretches, the resin tries to enter the extremely thin wall on both sides like a wedge. However, when a load is applied that moves the ball head of the ball stud toward the opening of the housing, the ball head moves toward the opening of the housing, causing the conical seat and the ball head to
The opening edge of the bearing is firmly pinched, and the opening edge of the bearing is pressed against the surfaces of the conical seat and the ball head.
Since the resin at the opening edge of the bearing is pushed back into the thick shoulder portion, the resin is eventually trapped in the shoulder portion and its flow is blocked.

Embodiment The structure of an embodiment of the present invention will be explained below with reference to the drawings.

FIG. 1 shows the ball joint 1, and FIG. 2 is an enlarged cross-sectional view of a portion thereof. In the figure, 2 is a ball stud having a ball head 4 at one end of a shaft portion 3.

Reference numeral 6 denotes a housing having a conical conical seat 9 extending substantially tangentially with respect to the ball head 4 of the ball stud 2 on the inner periphery adjacent to the opening 7, and a housing 6 connected to the large diameter side of the conical seat 9. It has a cylindrical seat 10 extending in a cylindrical shape in the axial direction, and the cylindrical seat 10 is formed slightly beyond the equator of the spherical head 4 to the top side of the spherical head.

At the lower end of the cylindrical seat 10 is a truncated conical stepped surface 11.
are connected to each other, and a large-diameter cylindrical portion 12 is formed on the large-diameter side thereof.

The intersection angle θ between the inclination of the conical seat 9 and the axis of the housing 6 is set to about 52 degrees in the embodiment, and the opposing gap between the conical seat 9 and the cylindrical seat 10 and the ball stud spherical head 4 at the closest point is as follows. It must be made extremely small, and in the embodiment, it is set to about 0.8 mm.

Reference numeral 19 designates a synthetic resin bearing on the high load bearing side, the inner circumference of which is adapted to the shaft portion 3 side of the ball head 4 of the ball stud 2, and the outer circumference of which is fitted to the conical seat 9 and the cylindrical seat 1 of the housing 6.
0 and the large diameter cylindrical part 12.

This bearing 19 has a shoulder portion 21 which is the thickest part near the intersection of the conical seat 9 and the cylindrical seat 10.
, an opening edge 24 having an extremely thin wall thickness at the closest point between the conical seat 9 and the spherical head 4, and an opening edge 24 at the closest point between the cylindrical seat 10 and the spherical head 4. an equatorial portion 25 having an extremely thin wall thickness comparable to that of the cylindrical portion 25, a cylindrical portion 22 connected below the equatorial portion 25, and a flange that is connected to the cylindrical portion 22 and expands in diameter in a truncated conical shape downward. It is composed of a shoulder 27 portion and a flange portion 23 having a thick outer peripheral portion.

Therefore, both sides of the thick shoulder portion 21 of the bearing 19 have a wedge shape, with the wall thickness being extremely thin at the portion closest to the ball head 6.

Further, the ball head receiving surface 20, which is the inner circumferential surface of the shoulder portion 21 of the bearing 19, is formed into a curved surface with a radius _{R2 larger than the radius R1 of} the ball head 4.
It abuts the ball head 4 most strongly in the direction of the intersection of the conical seat 9 and the cylindrical seat 10 when viewed from approximately the center of the ball.

That is, the virtual center O ₂ of the ball head receiving surface 20 is
It is located closer to the tip of the ball head 4 than the center O ₁ of the ball head 4 and is located away from the central axis of the housing 6 in the radial direction.

Therefore, the head spherical surface 5 of the ball head 4 is
There is a gap 1 between the opening edge 24 and the equatorial portion 25 of
7, 18 or tend to contact the bearing 19 weaker than the thick shoulder 21.

The flange portion 23 of the bearing 19 is connected to a flange shoulder 27 and a step surface 1 of the housing 6 so that the facing surface of the bearing 19 is set in close contact with the conical seat 9 and the bearing 19 is securely and firmly fixed to the housing 6.
1, and is press-fitted into the large-diameter cylindrical portion 12 from its free state with a tightening allowance P, as shown by the two-dot chain line.

And the tightening amount P and the clearance L of this flange portion 23
As the bearing 19 is press-fitted, the cylindrical portion 22 curves to form a holding portion 26 that holds the ball head 4 by holding the tip side of the ball head 4 from the equator.

Reference numeral 16 denotes a bearing for wear compensation, which is made of urethane rubber or the like to reduce the load burden, and is assembled in a compressed state in the axial direction to absorb wear of the sliding part.

The sliding portions between the bearings 19, 16 and the ball head 4 are coated with a suitable lubricating oil such as grease.

A closing plate 15 closes one end of the housing 6, and is crimped and fixed by deforming the edge of the housing 6 with a roller or the like.

Next, the assembly of the ball joint 1 will be explained.

First, the bearing 19 is press-fitted into the housing 6, the flange portion 23 is firmly connected to the large diameter cylindrical portion 12, and the bearing 19 is brought into close contact with the conical seat 9. Next, after applying lubricating oil to the inner surface of the bearing 19,
The ball head 4 of the ball stud 2 is fitted to the ball head 4, and the other bearing 16 is set on the ball head 4, and finally the closing plate 15 is crimped and fixed to the housing jig 6.

Effects As described above, according to the present invention, during normal use, the load transmitted to the bearing by the ball head of the ball stud is transferred to the shoulder of the thick part of the bearing near the intersection of the conical seat and the cylindrical seat of the housing. In addition to this, the resin on both sides of the shoulder has a wedge-like shape with an extremely thin wall thickness at the closest point between the seat and the ball head, so the elongation of the shoulder causes the resin to spread out on both sides like a wedge. The ball stud tries to enter the extremely thin walled part, but if a load is applied that moves the ball head of the ball stud in the direction of the opening of the housing, the ball head will move in the direction of the opening of the housing and meet the conical seat. The ball head firmly squeezes the opening edge of the bearing, and the opening edge of the bearing is pressed against the surfaces of the conical seat and the ball head, causing the resin on the opening edge of the bearing to become a thick part. Since the resin acts in the direction of pushing it back to the shoulder, the resin is eventually confined in the shoulder and its flow is blocked, so the ball joint can maintain its low operating torque while maintaining high durability without making the bearing thicker than necessary. Load performance can be improved.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and is a cross-sectional plan view of a ball joint. FIG. 2 is a partially enlarged sectional view of FIG. 1. (Explanation of symbols), 1...Ball joint. 2
...Ball Stud. 4... Ball head. 6...Housing. 7...Opening. 9... Conus. 10... Cylindrical seat. 12...Large diameter cylindrical part. 16, 19...Bearing. 20... Ball head receiving surface. 21...Shoulder. 24
...Aperture edge. R ₁ ...radius. R ₂ ...radius.

Claims (1)

[Claims] 1 Housing 6 with one end open and the other end closed
The housing 6 is a ball joint in which the ball head 4 at one end of the ball stud 2 is swingably supported via synthetic resin bearings 19 and 16.
is a conical conical seat 9 on the inner periphery adjacent to the opening 7.
and a cylindrical seat 1 connected to the large diameter side of the conical seat 9 and extending cylindrically in the axial direction of the housing 6.
0, and the bearing 19 has a shoulder portion 21 that is the thickest part near the intersection of the conical seat 9 and the cylindrical seat 10, and has a cross section that tapers toward the opening 7 of the housing 6. Wedge-shaped opening edge 2
4 and is the inner peripheral surface of the bearing 19, the radius R ₂ of which is the inner circumferential surface of the bearing 19.
It is characterized by being a spherical surface with a radius larger than _R1 , and making the strongest contact with the spherical head 4 in the direction of the intersection of the conical seat 9 and the cylindrical seat 10 when viewed from approximately the center of the spherical head 4. ball joint.