JP2014066333A - Ball joint dust cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball joint dust cover capable of suppressing occurrence of a so-called opening phenomenon of a small-diameter aperture that may cause separation of contact between a lip part of the small-diameter opening and a shaft even in low-temperature atmosphere, capable of preventing occurrence of danger that may generate vibration in a cover waist part and cause breakage because relative rotation motion between the small-diameter aperture and the shaft is not damaged, and having high durability.SOLUTION: In a ball joint dust cover 6 made of an elastic material and configured so that a ball head part 2 formed on one end of a ball stud 1 is held in a socket 3, a shaft 4 on the other end of the ball stud 1 is fastened and fixed on a knuckle 5, a large-diameter aperture on the one end is fixedly held on an outer peripheral surface of the socket 3, and a small-diameter aperture on the other end in which a reinforcing ring 9 is buried is held on the shaft 4, the reinforcing ring 9 includes a screw groove inner peripheral surface 91 to be screwed with a screw part 41 formed on an outer peripheral surface of the shaft 4.

Description

The present invention relates to a dust cover for a ball joint.
The present invention also relates to a ball joint dust cover used for an automobile suspension device, a steering device, and the like.

  Conventionally, a ball joint dust cover shown in FIG. 3 is known as a ball joint to which a dust cover is attached for the purpose of dust prevention and waterproofing of a ball joint joint. (Patent Document 1)

In this kind of ball joint dust cover sealing structure, a ball head 200 formed at one end of a ball stud 100 is held in a socket 300.
The shaft 400 at the other end of the ball stud 100 is fastened and fixed to the knuckle 500.
On the other hand, one end large-diameter opening 800 having a substantially U-shaped cross section of the dust cover 600 made of an elastic material is fixed and held in an annular groove 310 formed on the outer peripheral surface of the socket 300 by an annular pressing ring 700. The small end opening 150 is held by the shaft 400.
The pressing ring 700 uses a circlip having a substantially rectangular cross section.

When this type of conventional dust cover 600 made of elastic material is swung in a state where the ball stud 100 is inclined as shown in FIG. 3, on the side where the film portion of the elastic material dust cover 600 extends (the right side in the figure), Since a force for stretching the small diameter opening 150 acts, a contact phenomenon between the lip portion of the small diameter opening 150 and the knuckle 500 occurs, so-called opening phenomenon of the small diameter opening 150 occurs.
As a result, the sealing performance at the small-diameter opening 150 is lowered, and the problem that earth and sand and dust enter the dust cover 600 from the outside is caused.

In particular, the rubber constituting the dust cover 600 made of an elastic material loses its elasticity in a low temperature atmosphere, and the followability of the film portion with respect to the swinging motion of the ball joint is reduced. As a result, the opening phenomenon in which the seal lip portion separates from the shaft 400. It was found that the problem occurred significantly.
One way to prevent this phenomenon is to completely fix the other end small-diameter opening 150 (lip portion) and the shaft 400 side. The other end small-diameter opening 150 (lip portion) is completely fixed. In this case, the dust cover waist was shaken by the sliding movement of the ball joint, resulting in the risk of breakage.

JP 62-137408 A

  The present invention has been made in view of such problems, and suppresses the occurrence of the so-called opening phenomenon of the small-diameter opening, in which the contact between the lip of the small-diameter opening and the shaft is released even in a low-temperature atmosphere. The purpose is to provide a ball joint dust cover with good durability that does not impair the relative rotational movement between the small-diameter opening and the shaft, causing vibration at the waist of the cover and no risk of breakage. And

  In the dust cover for a ball joint according to the present invention, the ball head formed at one end of the ball stud is held in the socket, the shaft at the other end of the ball stud is fastened and fixed to the knuckle, and the large-diameter opening is at the one end. In the dust cover for ball joint made of elastic material, which is fixedly held on the outer peripheral surface of the socket and the other end small-diameter opening embedded with the reinforcing ring is held on the shaft, the reinforcing ring is formed on the outer peripheral surface of the shaft A screw groove inner peripheral surface that is screwed into the screw portion is provided.

The present invention has the following effects.
According to the dust cover for a ball joint of the invention described in claim 1, since the reinforcing ring is provided with the thread groove inner peripheral surface that is screwed with the screw portion formed on the shaft outer peripheral surface, However, the contact between the lip portion of the small-diameter opening and the shaft is released, so that the opening phenomenon of the so-called small-diameter opening at the other end is suppressed, and the relative rotational motion between the small-diameter opening at the other end and the shaft is not impaired. Therefore, the cover waist is shaken, there is no risk of breakage, and durability is good.
Furthermore, according to the dust cover for ball joint of the invention described in claim 2, since it has a structure having a lip portion which is in elastic contact with the outer peripheral surface of the shaft, it is possible to prevent dirt and dust from entering the dust cover from the outside. Can be effectively blocked.

  Furthermore, according to the dust cover for a ball joint of the invention described in claim 3, since the inner peripheral surface of the thread groove is a discontinuous groove provided at equal intervals on the circumference, the mold release at the time of forming the dust cover is prevented. It is easy and can reduce the sliding resistance during the relative rotational movement between the small-diameter opening and the shaft.

The longitudinal cross-sectional view of the dust cover for ball joints based on this invention. The partial expanded sectional view before mounting | wearing with the other end small diameter opening part of the dust cover for ball joints based on this invention. The longitudinal cross-sectional view of the dust cover for ball joints based on a prior art.

Hereinafter, modes for carrying out the present invention will be described.
As shown in FIGS. 1 and 2, the ball joint dust cover according to the present invention has a ball head 2 formed at one end of a ball stud 1 held in a socket 3, and the other end of the ball stud 1. The shaft 4 is fastened and fixed to the knuckle 5, one end large-diameter opening 8 is fixedly held on the outer peripheral surface of the socket 3, and the other end small-diameter opening 7 embedded with the reinforcing ring 9 is held on the shaft 4. It has become.

The reinforcing ring 9 includes a thread groove inner peripheral surface 91 that is screwed with a screw portion 41 formed on the outer peripheral surface of the shaft 4.
Furthermore, the other end small-diameter opening 7 is formed with a lip portion 71 in elastic contact with the outer peripheral surface of the shaft 4 on one end large-diameter opening 8 side (upper and lower side in the figure) of the inner peripheral surface 91 of the thread groove. .
The lip portion 71 is formed integrally with the dust cover 6 main body made of an elastic material, and is attached to the outer peripheral surface of the shaft 4 with a certain tightening margin (about 0.8 mm / dia).
Therefore, it is possible to more effectively prevent dust from entering the elastic material dust cover 6 from the outside, and to prevent the grease from flowing out from the elastic material dust cover 6.
In the present embodiment, two annular lip portions 71 are provided. However, the number of lip portions 71 can be changed according to the use environment.
In this embodiment, the material of the reinforcing ring 9 is a resin material, but may be a metal material.

  Further, the screw portion 41 formed on the outer peripheral surface of the shaft 4 of the ball stud 1 can be formed in advance by cutting, but the sleeve formed with the screw portion 41 is fitted to the outer peripheral surface of the shaft 4. It is good also as a form provided.

The thread groove inner peripheral surface 91 formed in the reinforcing ring 9 is formed in a screw shape corresponding to the screw portion 41 by a molding die when the elastic material dust cover 6 main body is molded. The shape of the groove inner peripheral surface 91 may be discontinuous grooves provided on the circumference at equal intervals.
This makes it easy to release the dust cover made of elastic material, and lowers the sliding resistance during the relative rotational movement between the other end small-diameter opening 7 and the shaft 4.

  Further, when attaching the elastic material dust cover 6 to the ball stud 1, while rotating the elastic material dust cover 6 and the ball stat 1 relatively, the thread groove inner peripheral surface 91 of the reinforcing ring 9 and the outer peripheral surface of the shaft 4. The screw part 41 formed in the above is screwed together.

In this way, the screw groove 41 formed on the inner peripheral surface 91 of the thread groove of the reinforcing ring 9 and the outer peripheral surface of the shaft 4 is screwed, so that the lip portion 71 of the small-diameter opening 7 on the other end is also provided in a low temperature atmosphere. Made of an elastic material because the contact between the shaft 4 and the other end small-diameter opening 7 is prevented from occurring, and the other end small-diameter opening 7 and the shaft 4 are not damaged relative to each other. The dust cover has vibration at the waist and there is no risk of breakage, and durability is good.
Since the threaded groove inner peripheral surface 91 of the reinforcing ring 9 and the threaded portion 41 formed on the outer peripheral surface of the shaft 4 are screwed together, the other rotational movement between the other end small-diameter opening 7 and the shaft 4 causes other Although the end small-diameter opening 7 slightly moves in the axial direction, it is slight and does not cause a problem. However, it is also considered that a margin (gap) is provided in advance with the knuckle 5 side.

  The material of the dust cover 6 made of an elastic material is appropriately selected from a rubber-like elastic material such as chloroprene and a thermoplastic elastomer such as a polyester-based elastomer and a thermoplastic polyurethane.

  Further, grease is enclosed in the dust cover 6 made of an elastic material.

On the other hand, the one-end large-diameter opening 8 having a substantially U-shaped cross section of the dust cover 6 made of an elastic material is fixed and held by an annular pressing ring 11 in an annular groove 31 formed on the outer peripheral surface of the socket 3. It has become.
The holding ring 11 is a circlip having a substantially rectangular cross section.

  Further, the present invention is not limited to the best mode for carrying out the invention described above, and various other configurations can be adopted without departing from the gist of the present invention.

  It can be used for ball joints used in automobile suspension systems and steering systems.

DESCRIPTION OF SYMBOLS 1 Ball stat 2 Ball head 3 Socket 4 Shaft 5 Knuckle 6 Dust cover 7 made of elastic material Other end small-diameter opening 8 One end large-diameter opening 9 Reinforcement ring 11 Press ring 41 Screw part 71 Lip part 91 Screw groove inner peripheral surface

Claims (3)

The ball head (2) formed at one end of the ball stud (1) is held in the socket (3), and the shaft (4) at the other end of the ball stud (1) is fastened and fixed to the knuckle (5). The one end large diameter opening (8) is fixed and held on the outer peripheral surface of the socket (3), and the other end small diameter opening (7) embedded with the reinforcing ring (9) is held on the shaft (4). In the ball joint dust cover (6),
The dust cover for a ball joint, wherein the reinforcing ring (9) includes a thread groove inner peripheral surface (91) screwed with a screw portion (41) formed on the outer peripheral surface of the shaft (4). .   The other end small-diameter opening (7) is on the one end large-diameter opening (8) side of the thread groove inner peripheral surface (91), and the lip portion (71) is in elastic contact with the outer peripheral surface of the shaft (4). The dust cover for a ball joint according to claim 1, further comprising:   The dust cover for a ball joint according to claim 1 or 2, wherein the inner peripheral surface (91) of the thread groove is a discontinuous groove provided on the circumference at equal intervals.

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