JP2012122489A - Dust cover for ball joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust cover for a ball joint, which maintains performance of the dust cover even when the membrane portion of the dust cover is broken by collision with pebbles, contact with a peripheral member, or the like.SOLUTION: The dust cover for a ball joint made of rubber-like elastic material is configured in such a manner that a ball head portion formed at one end of a ball stud is held in a socket, a shaft portion at the other end of the ball stud is fastened and fixed to a knuckle, a large diameter opening at one end is fixed and held on the outer circumferential face of the socket, and a small diameter opening at the other end is held on the outer circumferential face of a retainer fitted and held on the shaft portion, and having an L-shaped cross-section, and the dust cover has a drum-shaped membrane portion outwardly protruding and connecting the large diameter opening and the small diameter opening. The dust cover also includes an inner membrane portion made of a rubber-like elastic material, whose one end is integrally fixed to the retainer and the other end is fixed and held to the outer circumferential face of the socket, which is present inside the above membrane portion, and which has a drum-like shape.

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 the ball joint joint. (Patent Documents 1 and 2)

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 as shown in FIG.
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 of the rubber elastic material dust cover 600 is fixedly held by the snap ring 900 on the outer peripheral surface of the socket 300, and the other end small-diameter opening 150 is held by the shaft 400. ing.
And the whole film | membrane part 700 which has connected the large diameter opening part 800 and the small diameter opening part 150 is exhibiting the drum shape which protruded outside.

The conventional dust cover 600 plays a role of preventing water and dust from entering the ball joint and preventing grease from flowing out of the ball joint.
However, since the dust cover 600 is made of a rubber-like elastic material, there is a risk that the dust cover 600 may be damaged due to collision of pebbles, contact with peripheral members, and the like.
When the dust cover 600 is damaged, the problem of allowing the outflow of grease in the ball joint and the intrusion of water, dust or the like into the ball joint is immediately caused.

Therefore, a mode in which the dust cover is used in a doubled manner has been proposed. (Patent Document 3)
However, the double-diameter structure in the small-diameter opening causes a problem that sufficient sealing performance in the small-diameter opening cannot be obtained.

Japanese Utility Model Publication No. 4-32313 JP 2004-92776 A Japanese Utility Model Publication No. 1-60078

  The present invention maintains the performance of the dust cover even when the film portion of the dust cover is torn due to collision of pebbles or the like, contact with peripheral members, etc. An object of the present invention is to provide a dust cover for a ball joint.

In the dust cover for ball joint according to the present invention, a ball head formed at one end of the ball stud is held in the socket, and a shaft portion at the other end of the ball stud is fastened and fixed to a knuckle. Is fixed and held on the outer peripheral surface of the socket, and the other end small diameter opening portion is held on the outer peripheral surface of the retainer having an L-shaped cross section fitted and held on the shaft portion, and the large diameter opening and the small diameter opening In a dust cover for a ball joint made of a rubber-like elastic material provided with a substantially drum-shaped membrane portion projecting outside.
It is provided with a substantially drum-shaped rubber-like elastic inner membrane part existing inside the membrane part, one end of which is integrally fixed to the retainer and the other end is fixedly held on the outer peripheral surface of the socket. It is characterized by.

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 performance of the dust cover is maintained and the small diameter is maintained even if the film portion of the dust cover is torn due to the collision of pebbles, contact with peripheral members, and the like. There is no problem that the sealing function is lowered in the opening.
Furthermore, according to the dust cover for a ball joint of the invention described in claim 2, since the snap ring used conventionally can be used, it can be manufactured at low cost.

Furthermore, according to the dust cover for a ball joint of the invention described in claim 3, the sealing function at the large-diameter opening can exhibit the same good sealing function as the conventional one, and the large-diameter opening also in the double membrane structure. It is possible to further improve the reliability of the function of preventing the part from coming off.
Furthermore, according to the dust cover for a ball joint of the invention described in claim 4, the expansion and contraction function of the dust cover is not hindered.

  Furthermore, according to the dust cover for a ball joint of the invention described in claim 5, since the material suitable for the environmental difference between the inside and outside of the ball joint can be selected, the reliability of the dust cover can be improved.

The longitudinal cross-sectional view of the dust cover for ball joints based on this invention. The figure which showed the 2nd aspect which concerns on this invention with the longitudinal cross-section. 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 FIG. 1, 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 portion 4 is fastened and fixed to the knuckle 5, and one end large-diameter opening portion 8 is fixed and held on the outer peripheral surface of the socket 3, and the other end small-diameter opening portion 15 is fitted and held on the shaft portion 4. The retainer 6 has a basic structure including a substantially drum-shaped film portion 7 that is held on the outer peripheral surface of the retainer 6 and projects outwardly connecting the large-diameter opening 8 and the small-diameter opening 15.

Then, one end 711 is integrally fixed to the retainer 6, and the other end 712 is fixedly held on the outer peripheral surface of the socket 3. It is set as the structure equipped with.
In this first aspect, the other end 712 of the inner membrane portion 71 is a snap fitted to the outer peripheral surface of the large-diameter opening 8 between the outer peripheral surface of the socket 3 and the inner peripheral surface of the large-diameter opening 8. The ring 9 is fastened and fixed.
Further, a seal lip portion 151 that is in close contact with the outer peripheral surface of the retainer 6 is formed on the inner peripheral surface of the small-diameter opening 15.

As a result, even in the double membrane structure, a good sealing function of the small-diameter opening 15 can be exhibited, so that water, dust, etc. enter the gap between the membrane portion 7 and the inner membrane portion 71, and the function of the dust cover Will not be damaged.
Further, the inner film portion 71 is formed thinner than the film portion 7.
For this reason, even in the double membrane structure, the expansion and contraction function of the dust cover is not hindered.

Next, a second mode according to the present invention will be described with reference to FIG.
The difference from the first embodiment is that the other end 712 of the inner membrane portion 71 is integrally fixed to a press-fit ring 72 fitted and fixed to the outer peripheral surface of the socket 3, and the large-diameter opening 8 is press-fit ring 72. It is the point which becomes the structure fitted and fixed to the outer peripheral surface of this.

Further, a locking ring 81 that is engaged with the outer peripheral surface of the press-fit ring 72 is embedded in the large-diameter opening 8.
For this reason, the sealing function in the large-diameter opening 8 can exhibit the same good sealing function as the conventional one, and the reliability of the function of preventing the large-diameter opening 8 from coming out can be further improved in the double membrane structure. I can do it.

The material of the film part 7 and the inner film part 71 is appropriately selected from a rubbery elastic material such as chloroprene, or a thermoplastic elastomer such as a polyester-based elastomer or a thermoplastic polyurethane.
Furthermore, in order to make the configuration suitable for the difference in environment between the inside and outside of the ball joint, the reliability of the dust cover can be improved by using different materials for the inner membrane 71 and the membrane 7. Can be increased.

  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 stud 2 Ball head 3 Socket 4 Shaft part 5 Knuckle 6 Retainer 7 Film part 8 Large diameter opening part 9 Snap ring 15 Small diameter opening part 71 Inner film part 72 Press-fit ring 81 Locking ring 711 One end 712 Other end

Claims (5)

A ball head (2) formed at one end of the ball stud (1) is held in the socket (3),
The shaft (4) at the other end of the ball stud (1) is fastened and fixed to a knuckle (5), one end large-diameter opening (8) is fixedly held on the outer peripheral surface of the socket (3), and the other end has a small diameter. An opening portion (15) is held by an outer peripheral surface of an L-shaped retainer (6) fitted and held on the shaft portion (4), and the large-diameter opening portion (8) and the small-diameter opening portion (15). In the dust cover for a ball joint made of an elastic material provided with a substantially drum-shaped film portion (7) projecting outside,
One end (711) is integrally fixed to the retainer (6), and the other end (712) is fixedly held on the outer peripheral surface of the socket (3). A dust cover for ball joints, comprising an inner film part (71) made of an elastic material having a shape.   The other end (712) of the inner membrane part (71) is fitted to the outer peripheral surface of the large-diameter opening (8) between the outer peripheral surface of the socket (3) and the large-diameter opening (8). 2. The dust cover for a ball joint according to claim 1, wherein the dust cover is fastened and fixed by a combined snap ring.   The other end (712) of the inner membrane part (71) is integrally fixed to a press-fit ring (72) fitted and fixed to the outer peripheral surface of the socket (3), and the large-diameter opening (8) is A locking ring (81) that engages with the outer peripheral surface of the press-fit ring (72) is embedded in the large-diameter opening (8) while being fitted and fixed to the outer peripheral surface of the press-fit ring (72). The ball joint dust cover according to claim 1, wherein the dust cover is a dust cover.   The ball joint dust according to any one of claims 1 to 3, wherein a thickness of the inner membrane portion (71) is thinner than a thickness of the membrane portion (7). cover.   The ball joint dust according to any one of claims 1 to 4, wherein the inner film portion (71) and the film portion (7) are made of different materials. cover.

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