JPH0594579U - Dust cover - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a dust cover capable of increasing the contact surface pressure of the sealing surface while ensuring the elasticity of the mounting portion in the radial direction. [Structure] An annular mounting portion 9 that is expandable and contractible in the radial direction is provided,
In the dust cover 7 in which the inner peripheral surface 13 of the mounting portion 9 is in close contact with the shaft 4 to form the sealing surface B, the mounting portion 9 is expandable and contractible in the radial direction. A spring 14 is provided which gives a contracting force in the radial direction to the mounting portion in a state of being in close contact with the shaft.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dust cover used for a seal of a ball joint part of a steering mechanism of an automobile or a construction machine.

[0002]

[Prior Art]

 FIG. 3 shows a conventional example. Reference numeral 100 denotes a socket, and a spherical bearing 101 is provided in the socket 100. On the other hand, 102 is a stud, and the stud 102 has a shaft portion 103 and a sphere 104. The sphere 104 is slidably held by the spherical bearing 101. A knuckle arm 105 having a diameter larger than that of the shaft 103 is integrally provided on the shaft 103.

Reference numeral 106 denotes a dust cover, and the dust cover 106 is integrally formed of a rubber-like elastic body. The dust cover 106 has a cylindrical film portion 107 and annular mounting portions 108 and 109 provided at both ends of the film portion 107.

An inner peripheral surface 110 of the one mounting portion 108 is in close contact with the shaft 103 to form a sealing surface A. Further, the mounting portion 108 is formed of a single rubber-like elastic body in order to secure radial stretchability when mounting over the knuckle arm 105 as indicated by a chain double-dashed line.

Further, the other mounting portion 109 is mounted and fixed to an annular mounting groove 111 provided on the socket 100 side. Then, grease (not shown) is filled in the dust cover 106, and the grease lubricates the sliding surface between the ball 104 and the spherical bearing 101.

[0006]

[Problems to be solved by the device]

 However, in the above-mentioned conventional example, since the mounting portion 108 secures the elasticity in the radial direction, the contracting force in the state of being in close contact with the shaft 103 is insufficient. As a result, the contact surface pressure of the sealing surface A is lowered, and there is a possibility that the sealing performance may be deteriorated, such as leakage of grease and intrusion of external dust.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a dust cover capable of increasing the contact pressure of the sealing surface while ensuring the elasticity of the mounting portion in the radial direction. There is.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a dust cover having a ring-shaped mounting portion that is expandable and contractible in the radial direction, the inner peripheral surface of the mounting portion being in close contact with a shaft to form a sealing surface. The mounting portion is provided with a tensioning ring that is expandable and contractible in the radial direction and that applies a contracting force in the radial direction to the mounting portion while the mounting portion is in close contact with the shaft.

[0009]

[Action]

 When the mounting portion is extended in the radial direction in order to pass over the large diameter portion of the shaft, the elastic force applying ring is also extended in the same direction, so that the elasticity is secured. Further, when the mounting portion is in close contact with the shaft, the contracting force in the radial direction of the tightening force applying ring is applied to the mounting portion, so that the contact surface pressure of the sealing surface increases.

[0010]

【Example】

 FIG. 1 shows a dust cover for a ball joint to which the present invention is applied. In the figure, 1 is a socket, and a spherical bearing 2 is provided in the socket 1. 3 is a stud, and the stud 3 has a ball 5 at the end of the shaft 4. A knuckle arm 6 having a diameter larger than that of the shaft 4 is integrally provided on the shaft 4.

Reference numeral 7 denotes a dust cover integrally formed of a rubber-like elastic body, and the dust cover 7 has mounting portions 9 and 10 at both ends of a cylindrical film portion 8.

The mounting portion 9 is expandable and contractible in the radial direction, and the inner diameter of its inner peripheral surface is set to be substantially the same as or slightly smaller than the outer diameter of the shaft 4. A coil-shaped spring 14 serving as a tensioning ring is embedded in the mounting portion 9 by vulcanization molding. The spring 14 is expandable and contractible in the radial direction, and applies a contracting force in the radial direction to the mounting portion 9 with the inner peripheral surface 13 in close contact with the shaft 4.

A seal lip 15 that comes into contact with the lower end surface of the knuckle arm 6 is integrally provided on the upper surface of the mounting portion 9. The outer diameter of the mounting portion 9 is set to be substantially the same as the outer diameter of the knuckle arm 6 in this embodiment.

On the other hand, an annular mounting groove 11 is provided on the outer periphery of the socket 1, and another mounting portion 10 is mounted in the mounting groove 11. Reference numeral 12 is a clamp mounted on the outer periphery of the mounting portion 10.

Grease (not shown) is sealed inside the dust cover 7 having the above-described structure, and the grease lubricates the sliding surface between the ball 5 and the spherical bearing 2. The inner peripheral surface 13 of the mounting portion 9 is in close contact with the shaft 4 to form a sealing surface B.

By the way, when the dust cover 7 is mounted on the shaft 4, the mounting portion 9 located above the shaft 4 is radially extended as shown in FIG. .. At this time, since the spring 14 also extends in the same direction, there is no hindrance to the work.

When the mounting portion 9 is brought into close contact with the shaft 4 as shown in FIG. 1, the contracting force of the spring 14 is applied in addition to the contracting force of the mounting portion 9 itself, so that the contact surface pressure of the sealing surface B increases.

Therefore, there is no leakage of grease or intrusion of external dust, and the sealing performance is improved.

Although the spring 14 is embedded in the mounting portion 9 in the above embodiment, a groove may be provided on the outer periphery of the mounting portion 9 and the spring may be mounted in the groove.

[0020]

[Effect of the device]

 Since the present invention is configured as described above, the elasticity of the mounting portion can be secured, and the contact pressure of the sealing surface formed by the inner peripheral surface of the mounting portion and the shaft can be increased to improve the sealing performance. To do.

[Brief description of drawings]

FIG. 1 is a half sectional view of a ball joint dust cover according to an embodiment of the present invention.

2A and 2B are half cross-sectional views of a mounting portion of the dust cover of FIG. 1 when it is extended.

FIG. 3 is a half sectional view of a conventional dust cover.

[Explanation of symbols]

 1 Socket 2 Spherical Bearing 3 Stud 4 Shaft 5 Ball 6 Knuckle Arm 7 Dust Cover 8 Membrane 9, 10 Mounting Part 11 Mounting Groove 12 Clamp 13 Inner Surface B Sealing Surface

Claims (1)

[Scope of utility model registration request] 1. A dust cover having a ring-shaped mounting portion that is expandable and contractible in a radial direction, the inner peripheral surface of the mounting portion being in close contact with a shaft to form a sealing surface, wherein the mounting portion has a diameter of A dust cover that is expandable and contractible in a direction and is provided with a tightening force applying ring that applies a contracting force in a radial direction to the mounting portion while the mounting portion is in close contact with the shaft.