JP2013160326A - Dust cover for ball joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce strain to be applied to a membrane part of a dust cover and prevent a reduction in durability of the dust cover even when a shape of the dust cover becomes close to a cylindrical shape.SOLUTION: In a dust cover for a ball joint made of an elastic material, a ball head part formed at 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 large-diameter opening at one end is fixedly held to an outer peripheral surface of the socket, a small-diameter opening at the other end with a reinforcing ring embedded therein is held by the shaft; and a membrane part connecting the large-diameter and small-diameter openings is provided. An annular groove part is provided on the outer peripheral surface side of the membrane part, and an annular protrusion is provided on an inner peripheral surface side corresponding to the groove part.

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. 4 is known as a ball joint to which a dust cover is attached for the purpose of dust-proofing and waterproofing the 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, the large-diameter opening 80 at one end of the rubber elastic material dust cover 600 is fitted and held by a buried ring 801 at the step formed on the outer peripheral surface of the socket 300, and the other end at which the reinforcing ring 900 is buried. The small-diameter opening 70 is held on the shaft 400.

This kind of conventional dust cover 600 generally has a bell shape in general, but due to a reduction in the size of the socket 300 or the like, if the diameter difference between the ball stud 100 and the socket 300 decreases, There was a case where the dust cover 600 had to be set so as to approach the cylindrical shape as shown in FIG. 5 from the bell shape.
In other words, one end of the cylindrical portion 613 is connected to the large-diameter opening 80, and the other end of the cylindrical portion 613 is connected to the bending portion 614 having the small-diameter opening 70.

Thus, as the shape of the dust cover 600 approaches the cylindrical shape, the strain applied to the film portion 610 of the dust cover 600 tends to increase.
As a result, the durability of the film portion 610 of the dust cover 600 is lowered, and a problem occurs that a part of the circumference of the film portion 610 of the dust cover 600 is abnormally deformed to the inner diameter side when the dust cover 600 is set.

For this reason, a method of increasing the thickness of the film part and a method of providing an annular groove in the film part have been proposed. (Patent Document 1)
However, when the annular groove is provided in the film part, the distortion of the film part when the dust cover is swung is increased, which causes a problem of reducing the durability of the dust cover.
Further, when the thickness of the film portion is increased, a problem that the small-diameter opening of the dust cover falls off from the ball stud is caused.

JP 62-137408 A Japanese Utility Model Publication No. 58-189858

  The present invention has been made in view of such a problem, and even when the shape of the dust cover approaches a cylindrical shape, the distortion applied to the film portion of the dust cover is reduced, and the durability of the dust cover is reduced. The purpose is to deter.

  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. An elastic material provided with a membrane portion that is fixedly held on the outer peripheral surface of the socket, the other end small-diameter opening embedded with a reinforcing ring is held by the shaft, and connects the large-diameter opening and the small-diameter opening In the ball joint dust cover, an annular groove is provided on the outer peripheral surface side of the film portion, and an annular protrusion is provided on the inner peripheral surface side corresponding to the groove portion.

The present invention has the following effects.
According to the dust cover for a ball joint of the invention of claim 1, since the annular groove portion is provided on the outer peripheral surface side of the film portion and the annular protrusion portion is provided on the inner peripheral surface side corresponding to the groove portion, Even if the shape of the dust cover approaches a cylindrical shape, distortion applied to the film portion of the dust cover can be suppressed to a small extent, and a decrease in the durability of the dust cover can be suppressed.
Furthermore, according to the dust cover for a ball joint of the invention described in claim 2, since the cross-sectional shape of the groove part and the protrusion part is an arc shape, and the radius of the protrusion part is larger than the radius of the groove part, the dust cover The strain applied to the film portion can be suppressed to a lower level, and the decrease in the durability of the dust cover can be suppressed.

Furthermore, according to the dust cover for a ball joint of the invention as set forth in claim 3, it is particularly effective for a dust cover having a cylindrical part in the film part.
Furthermore, according to the dust cover for a ball joint of the invention described in claim 4, since the groove portion and the projection portion exist in the vicinity of the joint portion between the cylindrical portion and the curved portion, the strain applied to the film portion of the dust cover is further reduced. It is possible to suppress the decrease in the durability of the dust cover.

The longitudinal cross-sectional view of the dust cover for ball joints based on this invention. The longitudinal cross-sectional view before mounting | wearing with the dust cover for ball joints of 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. The longitudinal cross-sectional view before mounting | wearing with the dust cover for ball joints of FIG.

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, the one end large-diameter opening 8 in which the embedded ring 81 is embedded is fitted and held in the step provided on the outer peripheral surface of the socket 3, and the reinforcing ring 9 is embedded An end small-diameter opening 7 is held on the shaft 4 and has a basic configuration including a film part 61 that connects the large-diameter opening 8 and the small-diameter opening 7.

An annular groove 611 is provided on the outer peripheral surface side of the film portion 61, and an annular protrusion 612 is provided on the inner peripheral surface side corresponding to the groove 611.
For this reason, even if the shape of the dust cover 6 approaches a cylindrical shape, distortion applied to the film portion 61 of the dust cover 6 can be suppressed to a small extent, and a decrease in durability of the dust cover 6 can be suppressed.

As shown in FIG. 2, the cross-sectional shapes of the groove 611 and the protrusion 612 are arcuate, and the radius R2 of the protrusion 612 is larger than the radius R1 of the groove 611.
For this reason, the distortion applied to the film part 61 of the dust cover 6 can be suppressed to a lower level, and the deterioration of the durability of the dust cover 6 can be suppressed.

In the present embodiment, the cross-sectional shapes of the groove 611 and the protrusion 612 are arcuate, but an elliptical shape, a polygonal shape such as a triangular shape, or the like is appropriately selected and used.
The dust cover 6 generally has a bell shape, but when the diameter difference between the ball stud 1 and the socket 3 is reduced due to the size reduction of the socket 3, the shape of the dust cover 6 is reduced. There is a case where it has to be set so as to approach the cylindrical shape as shown in FIG. 2 from the bell shape.

That is, one end (lower end in the figure) of the cylindrical part 613 is connected to the large-diameter opening 8, and the other end (upper end in the figure) of the cylindrical part 613 is connected to the curved part 614 having the small-diameter opening 7. It has become.
Thus, the smaller the difference in diameter between the ball stud 1 and the socket 3, the greater the proportion of the cylindrical portion 613 in the film portion 61 of the dust cover 6.
As described above, as the shape of the dust cover 6 approaches the cylindrical shape, the strain applied to the film portion 61 of the dust cover 6 tends to increase.
As a result, the durability of the film part 61 of the dust cover 6 is lowered, and there is a problem that a part of the circumference of the film part 61 of the dust cover 6 is abnormally deformed to the inner diameter side when the dust cover is set. By providing the annular groove 611 on the outer peripheral surface side of the portion 61 and providing the annular protrusion 612 on the inner peripheral surface side corresponding to the groove 611, this problem can be solved.

  Furthermore, the groove portion 611 and the protruding portion 612 are configured to be present at the joint portion 615 between the cylindrical portion 613 and the curved portion 614, so that the distortion applied to the film portion 61 of the dust cover 6 can be further suppressed, and the dust cover 6 It is possible to suppress a decrease in durability.

  The dust cover 6 is filled with grease.

The reinforcing ring 9 is manufactured by punching from a steel plate such as SPCC.
For this reason, since the reinforcing ring 9 can be made thinner than when a resin material or the like is used, even if the diameter difference between the ball stud 1 and the socket 3 is reduced, the shape of the dust cover 6 is maintained in a bell shape. Things are more possible.

  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.

  On the other hand, the large-diameter opening 8 at one end of the rubber-like elastic material dust cover 6 is configured to be fitted and held in a stepped portion formed on the outer peripheral surface of the socket 3 by an annular buried ring 81 made of a metal material. ing.

The small-diameter opening 7 is provided with a dust lip 71 in elastic contact with the knuckle 5 and a seal lip 72 in elastic contact with the outer peripheral surface of the shaft 4.
For this reason, it is possible to more effectively prevent dust from entering the dust cover 6 from the outside, and to prevent the grease from flowing out of the dust cover 6.

  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.

1 Ball Stud 2 Ball Head 3 Socket 4 Shaft 5 Knuckle 6 Dust Cover 7 Small Diameter Opening 8 Large Diameter Opening 9 Reinforcement Ring 61 Film 71 Dustrip 72 Seal Lip 81 Buried Ring 611 Groove 612 Projection 613 Cylindrical 614 Curve 615 joint

Claims (4)

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). , One end large diameter opening (8) is fixed and held on the outer peripheral surface of the socket (3), the other end small diameter opening (7) embedded with a reinforcing ring (9) is held on the shaft (4), In the dust cover (6) for a ball joint made of an elastic material, including a film part (61) connecting the large diameter opening (8) and the small diameter opening (7),
An annular groove (611) is provided on the outer peripheral surface side of the film portion (61), and an annular protrusion (612) is provided on the inner peripheral surface side corresponding to the groove (611). Dust cover for joints.   The groove (611) and the protrusion (612) have arcuate cross-sectional shapes, and the protrusion (612) has a radius (R2) larger than a radius (R1) of the groove (611). The dust cover for a ball joint according to claim 1.   The dust cover for a ball joint according to claim 1 or 2, wherein the film part (61) is composed of a cylindrical part (613) and a curved part (614).   4. The ball joint according to claim 3, wherein the groove portion (611) and the protrusion portion (612) are present at a joint portion (615) between the cylindrical portion (613) and the curved portion (614). Dust cover.

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