Dust cover for ball joint

Abstract

In a dust cover for a ball joint, one end of a ball stud is retained within a socket, the other end is fixed by fastening a knuckle having a notch portion, one end large-diameter and other end small-diameter opening portions are respectively retained to the socket and the shaft, and a plate member is retained between an inner peripheral surface of the knuckle and an outer peripheral surface of the shaft. The plate member is constructed by an annular plate member, an elastic annular seal portion integrally formed in an inner peripheral side of the annular plate member, and an elastic engagement projection in the annular plate member in the knuckle side, and engaging with the notch portion. The annular seal portion is retained in a compression manner between an annular step portion in an inner peripheral surface of the knuckle and an outer peripheral surface of the shaft.

Claims

1. A dust cover configured for use with a ball joint that includes a ball stud having a spherical head portion and a shaft, a socket, and a knuckle, the spherical head portion of the ball stud being retained within the socket, and the shaft of the ball stud being fixed to the knuckle, the knuckle including a notch portion, and an annular step portion that is provided on an inner peripheral surface of the knuckle, the dust cover comprising: a first end large-diameter opening portion that is configured to be fixed and retained to an outer peripheral surface of the socket; a second end small-diameter opening portion that is configured to be retained to an outer peripheral surface of the shaft; and a plate member that is separate and apart from the second end small-diameter opening portion, and that is at least partially positioned between the inner peripheral surface of the knuckle located at a second end small-diameter opening portion side of the knuckle and the outer peripheral surface of the shaft, wherein the plate member includes an annular plate member that is made of a hard material, an annular seal portion that is integrally formed on an inner peripheral side of the annular plate member and is made of a rubber-like elastic material, and an engagement projection which is provided on the annular seal portion, engages with the notch portion of the knuckle, and is made of a rubber-like elastic material, and wherein the annular seal portion is configured to be compressed between the annular step portion of the knuckle and the outer peripheral surface of the shaft.

2. The dust cover according to claim 1, wherein a seal lip portion that contacts with the outer peripheral surface of the shaft is formed on an inner peripheral surface of the annular seal portion.

3. The dust cover according to claim 1, wherein a dust lip provided on the second end small-diameter opening portion that contacts the annular plate member.

4. The dust cover according to claim 2, wherein a dust lip provided on the second end small-diameter opening portion that contacts the annular plate member.

Description

BRIEF EXPLANATION OF THE DRAWINGS

(1) FIG. 1 is a vertical cross-sectional view of a dust cover for a ball joint according to the present invention in the case that the dust cover for the ball joint is cut in the same manner as a cross section along a line B-B in FIG. 6 showing a prior art;

(2) FIG. 2 is a partly enlarged view of FIG. 1;

(3) FIG. 3 is a plan view of a plate member which is used in FIG. 1;

(4) FIG. 4 is a cross-sectional view along a line A-A in FIG. 3;

(5) FIG. 5 is a vertical cross-sectional view of a taper alignment ball joint according to the prior art;

(6) FIG. 6 is a top elevational view of a pinch bolt type ball joint according to the prior art; and

(7) FIG. 7 is a side elevational view of FIG. 6.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

(8) A description will be given below of a mode for carrying out the present invention.

(9) As shown in FIGS. 1, 2, 3 and 4, a dust cover 6 for a ball joint according to the present invention is structured such that a spherical head portion formed in one end of a ball stud 1 is retained within a socket 3, and a shaft 4 in the other end of the ball stud 1 is fixed to a knuckle 5 side by fastening the knuckle 5 by a fastening means 520 such as a bolt.

(10) Further, the dust cover 6 is structured such that a one end large-diameter opening portion 8 is fixed and retained to an outer peripheral surface of the socket 3, and the other end small-diameter opening portion 7 is retained to the shaft 4.

(11) Further, a basic structure is provided by that the plate member 2 is retained between an inner peripheral surface of the knuckle 5 in the other end small-diameter opening portion 7 side and an outer peripheral surface of the shaft 4.

(12) This kind of knuckle 5 is used in the pinch bolt type ball joint, and is fastened and fixed onto the outer peripheral surface of the shaft 4 by the fastening means 520 such as the bolt, and an annular step portion 52 is formed in the inner peripheral surface of the knuckle 5 in the other end small-diameter opening portion 7 side (a lower surface side on the drawing).

(13) Further, the plate member 2 is constructed by an annular plate member 21 which is made of a hard material, an annular seal portion 22 which is integrally formed in an inner peripheral side of the annular plate member 21 and is made of a rubber-like elastic material, and an engagement projection 23 which is provided in a surface of the annular plate member 21 in the knuckle 5 side, engages with a notch portion 51 and is made of a rubber-like elastic material, and the annular seal portion 22 is retained in a compression manner between an annular step portion 52 which is provided in an inner peripheral surface of the knuckle 5 and an outer peripheral surface of the shaft 4.

(14) As mentioned above, the annular seal portion 22 is inserted between the annular step portion 52 provided in the inner peripheral surface of the knuckle 5 and the outer peripheral surface of the shaft 4, the knuckle 5 is thereafter fastened by the fastening means 520 such as the bolt, and a gap of the notch portion 51 is reduced. As a result, since the annular seal portion 22 is compressed between the annular step portion 52 and the outer peripheral surface of the shaft 4, a good sealing state can be achieved.

(15) Further, as shown in FIG. 4, since a seal lip portion 221 coming into contact with an outer peripheral surface of the shaft 4 is provided in an inner peripheral surface of the annular seal portion 22, it is possible to more securely achieve the seal between the annular seal portion 22 and the outer peripheral surface of the shaft 4.

(16) In the same manner, since the engagement projection 23 made of the rubber-like elastic material is inserted into the gap of the notch portion 51, the knuckle 5 is thereafter fastened by the bolt means 520, and the gap of the notch portion 51 is reduced, it is possible to maintain a state in which the engagement projection 23 is securely retained to the notch portion 51. As a result, it is possible to securely prevent the corotation of the plate member 2 in relation to the knuckle 5, and a stable sealing performance can be maintained.

(17) Further, since a dust lip 71 coming into close contact with a lower surface of the annular plate member 21 is provided in the other end small-diameter opening portion 7, it is possible to obtain the same water prevention and dust prevention effects as those of the taper alignment ball joint, even in the pinch bolt type ball joint.

(18) Further, a metal material and a resin material can be appropriately selected and employed as a material of the annular plate member 21.

(19) Further, a material of the dust cover 6 employs by appropriately selecting from rubber-like elastic materials such as chloroprene, polyester elastomer and thermoplastic elastomer such as thermoplastic polyurethane in conformity to intended use.

(20) Further, grease is sealed into the dust cover 6.

(21) On the other hand, a metal reinforcing ring is buried and integrated into the other end small-diameter opening portion 7 and the one end large-diameter opening portion 8 of the dust cover 6.

(22) Further, it goes without saying that the present invention is not limited to the best mode for carrying out the invention mentioned above, but can employ the other various structures without deviating from the scope of the present invention.

INDUSTRIAL APPLICABILITY

(23) The present invention can be used for the ball joint which is used in the suspension device, the steering device and so on of the motor vehicle.