JPH0570728B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in ball joints used in automobile suspension systems, steering systems, etc.

Prior Art In this type of ball joint, a hemispherical cup-shaped dust cover is compressed in the axial direction between the socket and the socket, with its axial height being restricted by a knuckle arm, and the inner peripheral surface of the dust cover is compressed in the axial direction. US Pat. No. 2,928,687 discloses a device in which the socket is slidably attached to the outer periphery of the socket.

Problems to be Solved by the Invention In the conventional dust cover described above, when the ball stud is tilted, the dust cover has no rigidity in the axial direction, so the shape of the inner circumference of the dust cover that is in contact with the outer circumference of the socket follows the movement of the ball stud. First, there is a problem that a sealing function between the outer periphery of the socket and the large opening of the dust cover cannot be secured.

In addition, if the dust cover's small opening is brought into contact with a compression member such as a knuckle arm that limits the height of the dust cover set, and the dust cover is compressed in the axial direction and attached to the socket, the dust cover's axial repulsive force may be insufficient. However, there is a problem in that an axial gap easily occurs between the contact surfaces of the compression member and the vicinity of the small opening of the dust cover.

Means for Solving the Problems The dust cover is installed with the front and back turned upside down, and the dust cover is installed with its axial height compressed.

Effect Tensile stress is generated on the outside of the dust cover that has been turned inside out, and compressive stress is generated on the inside, increasing the rigidity of the dust cover in the axial direction. Therefore, when the dust cover is compressed in the axial direction, a high repulsion force in the axial direction is obtained in the dust cover.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a ball joint 1 according to an embodiment of the invention. In the figure, reference numeral 2 denotes a ball stud, which consists of a handle 3 having a flange 4 projecting in the shape of a disk perpendicular to the axial direction, and a spherical head 5.

The collar 4 of the ball stud 2 also functions as a compression member that limits the set height of the dust cover 10.

A socket 6 has an opening 7 through which the handle 3 of the ball stud 2 protrudes, and a shoulder 8 is formed at the edge of the opening 7.

Reference numeral 9 denotes an upper bearing made of resin, which slidably supports the spherical head 5. A dust cover 10 is made of an elastic material such as urethane foam, and has a large opening 12 and a small opening 14 at both ends of a curved cylindrical body 11. The large opening 12 is attached to the outer periphery of the socket 6, and the small opening 14 is attached to the handle 3 of the ball stud 2 with a tightening margin.

The dust cover 10 may be formed not only from urethane foam but also from rubber or plastic rubber.

The dust cover 10 is formed in advance into a cup shape with a disc-shaped bottom, as shown by the two-dot chain line in FIG. Thereafter, when attaching the dust cover 10 to the ball joint 1, the front side 16 and the back side 17 are reversed. As a result, as shown by the solid line in Figure 2,
The front side 16 constitutes the inner circumferential surface of the dust cover 10, and the back side 17 constitutes the outer circumferential surface, and the dust cover body near the small opening 14 is transformed into a cylindrical body 11 curved into a nearly conical shape.

To attach the dust cover 10, attach the dust cover 1 to the pre-assembled ball joint.
In addition to the method of attaching the dust cover after flipping the dust cover inside out, the dust cover small opening 14 can be inserted between the flange 4 of the ball stud 2 and the spherical head 5.
There is also a method of press-fitting the dust cover 10 until it is located between the two sides, and then turning the dust cover 10 upside down and moving the large opening 13 to the outer periphery of the socket 6.

When the dust cover 10 is turned over, compressive stress is generated on the inner side (front 16) of the dust cover 10, and tensile stress is generated on the outer side (back 17), so that the repulsive force in the axial direction prevents the front and back from turning over. significantly higher than that of And dust cover 1
0, as shown by the two-dot chain line in FIG. 1, in the free state after the front and back are reversed, the conical curved cylindrical body 11 that is long in the axial direction is attached to the ball joint 1 in a compressed state in the axial direction. It means that it was done. Therefore, since the dust cover 10 always tries to return to the free state due to the repulsive force accumulated in the curved cylindrical body 11, there is a gap in the axial direction between the edge of the small opening 14 and the end surface of the collar 4, which is a compression member. There will never be any gaps.

In the above embodiment, the collar 4 protruding from the ball stud 2 functions as a compression member that compresses the dust cover 10 in the axial direction. may be fitted to compress the dust cover in the axial direction.

In addition, when the ball stud 2 is tilted, the dust cover 10, which has been turned upside down, always brings the inner circumferential surface of the dust cover 10 into close contact with the shoulder 8 of the socket 6 due to its repulsive force, thereby maintaining the sealing function therebetween. It is in.

Effects As described above, according to the present invention, tensile stress is generated on the outside of the dust cover that has been turned inside out, and compressive stress is generated on the inside, so that the dust cover rigidity in the axial direction increases, and the dust cover is compressed in the axial direction. (1) The contact surface between the edge of the small opening of the dust cover and the compression member that compresses the dust cover in the axial direction is The strong repulsive force accumulated in the curved cylindrical body ensures high sealing performance when the ball stud is tilted.

(2) Due to the strong repulsive force accumulated in the curved cylindrical body when the ball stud tilts, the inner peripheral surface of the dust cover always comes into close contact with the shoulder of the socket, ensuring a secure seal between them.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and is a cross-sectional plan view of a ball joint. FIG. 2 is a sectional plan view of a dust cover in an embodiment of the present invention. Explanation of symbols, 1...Ball joint, 2...
Ball stud, 3...handle, 6...socket,
7...Socket opening, 10...Dust cover, 1
2...Large opening, 14...Small opening, 16...Front, 1
7...Back.

Claims (1)

[Claims] 1. The ball stud 2, the socket 6 in which the handle 3 of the ball stud 2 swingably projects from the opening 7 at one end, and the large and small openings 12 and 14 that seal the socket opening 7 are formed in a curved cylindrical shape. In the ball joint 1 consisting of a dust cover 10 in the form of an elastic thin film, the dust cover 10 is shown in Table 1.
6. A ball joint characterized in that the dust cover 10 is installed with its back 17 reversed and the height in the axial direction of the dust cover 10 is compressed.