JP2014202288A - Dust cover for ball joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust cover for a ball joint capable of suppressing a so-called opening phenomenon of a small-diameter opening portion in which the small-diameter opening portion and a shaft are separated, even under a low temperature atmosphere, and improving sealing performance of the small-diameter opening portion.SOLUTION: In a dust cover 6 for a ball joint, a spherical head portion formed on one end of a ball stud is held in a socket, a shaft at the other end of the ball stud is fastened and fixed to a knuckle, a one-end large diameter opening portion 8 is fixed and retained to an outer peripheral face of the socket, and the other end small-diameter opening portion 7 on which a reinforcement ring made of a hard material is integrally formed, is held on the shaft. The reinforcement ring 9 has an inclined portion 91 extended while inclined radially inward from an inner peripheral side end portion toward an outer peripheral face of the shaft.

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.

  2. Description of the Related Art Conventionally, a ball joint dust cover shown in FIG. 5 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 other end small-diameter opening 150 in which the L-shaped metal reinforcing ring is embedded is held by the shaft 400. The rubber existing between the metal reinforcing ring and the shaft 400 is appropriately compressed, and exhibits a sealing property against the swinging motion of the ball stud 100 due to the repulsive force (tightening force) and followability of the rubber. It takes a shape to do.

However, this type of conventional dust cover 600 made of an elastic material swings in a state where the ball stud 100 is inclined as shown in FIG. 5, on the side where the film portion of the dust cover 600 made of an elastic material extends (the right side in the figure). Since the force that stretches the small diameter opening 150 is applied, the contact between the lip portion of the small diameter opening 150 and the knuckle 500 is released, and a 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.

  In addition, when such a mouth opening phenomenon occurs, not only earth and sand and dust enter the dust cover 600 from the outside, but also there is a risk that the grease enclosed in the dust cover 600 leaks out.

JP 62-137408 A

  The present invention has been made in view of such a problem, and even in a low-temperature atmosphere, the contact between the small-diameter opening and the shaft is released, and the occurrence of the so-called opening phenomenon of the small-diameter opening is suppressed, and the small-diameter opening An object of the present invention is to provide a dust cover for a ball joint having a good seal performance at a part.

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, which is fixedly held on the outer peripheral surface of the socket and the other end small-diameter opening formed integrally with a hard material reinforcing ring is held on the shaft,
The reinforcing ring has an inclined portion extending from the inner peripheral side end portion thereof in an inward radial direction toward the outer peripheral surface of the shaft.

The present invention has the following effects.
According to the dust cover for a ball joint of the first aspect of the present invention, the reinforcing ring reinforcing ring made of a hard material integrally formed with the small-diameter opening at the other end extends from the inner peripheral side end toward the outer peripheral surface of the shaft. In other words, the other end small-diameter opening is not contacted with the other end of the small-diameter opening, even in a low-temperature atmosphere. While suppressing, the sealing performance of a small diameter opening part at the other end can be maintained well.
Furthermore, according to the dust cover for a ball joint according to the second aspect of the present invention, since the elastic material layer in contact with the outer peripheral surface of the shaft at the time of mounting is provided on the inner peripheral surface of the inclined portion of the reinforcing ring, the shaft The sealing performance between the outer peripheral surface of the inner ring and the inner peripheral surface of the inclined portion of the reinforcing ring does not deteriorate.

  Furthermore, according to the dust cover for a ball joint of the invention described in claim 3, since there is a gap between the outer peripheral surface of the inclined portion of the reinforcing ring and the inner peripheral surface of the small-diameter opening at the other end, Deformation of the inclined portion of the ring in the radial direction is facilitated, and good adhesion to the outer peripheral surface of the shaft can be maintained.

The longitudinal section of the dust cover for ball joints concerning the present invention. The elements on larger scale of FIG. The longitudinal cross-sectional view before mounting | wearing with the dust cover shown in FIG. The elements on larger scale of FIG. The longitudinal cross-sectional view of the dust cover for ball joints based on a prior art.

Hereinafter, embodiments for carrying out the present invention will be described.
As shown in FIGS. 1, 2, 3 and 4, 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, The shaft 4 at the other end of the ball stud 1 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 integrally formed with a hard material reinforcing ring 9. The portion 7 has a basic configuration held on the shaft 4.

The reinforcing ring 9 integrally formed in the other end small-diameter opening 7 of the dust cover 6 is inclined radially inward from the inner peripheral end toward the outer peripheral surface 41 of the shaft 4 before mounting. An extending inclined portion 91 is provided.
The shape embedded in the other end small-diameter opening 7 of the reinforcing ring 9 has a substantially Z-shaped cross section, but various forms such as a L-shaped cross section can be applied.

In addition, since the inclined portion 91 of the reinforcing ring 9 is designed to be thinner than the other portions, from the state before mounting shown in FIGS. 3 and 4 to the state at the time of mounting shown in FIGS. It can be easily pushed outward in the radial direction.
That is, the inclined portion 91 expands from the radially inner end side, and is deformed into a cylindrical shape and held in close contact with the outer peripheral surface 41 of the shaft 4 as shown in FIG.

And since the force which the inclination part 91 always returns from the state of FIG. 2 to the state of FIG. 4 is acting on the outer peripheral surface 41 of the axis | shaft 4, even in a low temperature atmosphere, the other end small-diameter opening part 7 and the axis | shaft 4 It is possible to suppress the occurrence of the so-called opening phenomenon of the other-end small-diameter opening 7 that comes out of contact, and to favorably maintain the sealing performance of the other-end small-diameter opening 7.
Further, the tip of the inclined portion 91 is a guide portion 911 that extends while being inclined outward in the radial direction.

Due to the presence of the guide portion 911, the other end small-diameter opening 7 can be easily attached to the outer peripheral surface 41 of the shaft 4.
Further, as the material of the reinforcing ring 9, a metal material or a resin material is appropriately selected and used, but a resin material is preferable in consideration of sliding resistance with the shaft 4 and ease of deformation (easy diameter expansion). .

Further, an elastic material layer 92 that is in contact with the outer peripheral surface 41 of the shaft 4 is integrally provided on the inner peripheral surface of the inclined portion 91 at the time of mounting.
As a result, the sealing performance between the outer peripheral surface 41 of the shaft 4 and the inner peripheral surface of the inclined portion 91 of the reinforcing ring 9 can be maintained satisfactorily.
As the material of the elastic material layer 92, a rubber-like elastic material or a fluororesin material is used, but a fluororesin material is preferable from the viewpoint of keeping the sliding resistance low.

In addition, as shown in FIG. 4, the design is such that a gap X exists between the outer peripheral surface of the inclined portion 91 and the inner peripheral surface of the other end small-diameter opening 7 before mounting. Although it is not necessary to exist, the presence of the gap X makes it easy to deform the inclined portion 91 of the reinforcing ring 9 in the radial direction, and it is possible to maintain good adhesion to the outer peripheral surface 41 of the shaft 4.
Furthermore, a dust seal 61 is formed in the other end small-diameter opening 7 to elastically contact the lower surface of the knuckle 5 and prevent entry of earth and sand from the outside.

  The material of the dust cover 6 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.

  The dust cover 6 is filled with grease.

On the other hand, the one end large-diameter opening 8 having a substantially U-shaped cross section of the dust cover 6 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. Yes.
Although the circlip having a substantially rectangular cross section is used as the pressing ring 11, various pressing rings are used depending on applications such as a type in which a metal reinforcing ring is embedded and integrated in the large-diameter opening 8 at one end.

  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 Other end small diameter opening part 8 One end large diameter opening part 9 Reinforcement ring 11 Press ring 31 Groove part 61 Dust seal 91 Inclination part 92 Elastic material layer

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 fixedly held on the outer peripheral surface of the socket (3), and the other end small-diameter opening (7) integrally formed with a hard material reinforcing ring (9) is the shaft (4). In the ball joint dust cover (6) held by
The reinforcing ring (9) has an inclined portion (91) extending from the inner peripheral side end portion thereof in a radially inward direction toward the outer peripheral surface (41) of the shaft (4). Dust cover for ball joint.   The ball joint according to claim 1, wherein an elastic material layer (92) is provided on the inner peripheral surface of the inclined portion (91) so as to contact the outer peripheral surface (41) of the shaft (4) when mounted. Dust cover.   3. The ball joint dust according to claim 1, wherein a gap (X) exists between an outer peripheral surface of the inclined portion (91) and an inner peripheral surface of the other end small-diameter opening (7). cover.

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