Sealing device

Abstract

A sealing device comprising a projected portion having a rubber-like elastic member on the outer periphery of a seal member, an outer cylindrical portion extending toward the seal member on a flange portion of a sleeve member. This outer cylindrical portion covers an opening formed between the seal member and the flange portion, thereby preventing entry of dust. The outer cylindrical portion is further provided on the tip thereof with a bend portion which can be engaged with the projected portion. The projected portion, the outer cylindrical portion, and the bend portion form a small clearance which serves as a labyrinth seal. The projected portion is fixedly fitted with a projection ring for covering the opening formed between the seal member and the flange portion of the sleeve member so that the free end portion of the projection ring can be engaged with the flange. This free end portion of the protection ring and the flange portion form a small clearance, and this small clearance serves as a labyrinth seal.

Description

The recessed portion 9 is formed on the outer surface of the seal member 2; and the projected portion 10 outwardly protrudes in a radius direction from a bottom portion of the recessed portion 9. 37 39 and lip 38 provides the function of a labyrinth seal L3, thereby further improving the sealing performance against dust.

The protection ring 40 serves to function of making proper adjustments so that the protection ring 40 does not become eccentric in a radial direction, does not move out in a thrust direction, is not subjected to friction due to excessive load, nor is it deformed or damaged due to contact should the shaft 71 be eccentrically rotated or mounted onto the housing 7, thrust movement be generated, and as a consequence, should an improper load be applied to the two members in relative rotation. Thus, any deformation, damage, and generation of excessive heat due to sliding contact between the two members 2, 30 can be prevented, thereby providing a longstanding sealing performance.

Claims

1. A sealing device for sealing between concentric inner and outer members which are relatively rotatable with respect to one another, the sealing device comprising:

a seal member to be mounted onto the outer member, said seal member having a side facing outward towards the atmosphere, a seal lip for sealing a liquid in slidable contact with a sleeve member, an annular projected portion having a rubber-like elastic member on the outer periphery of said seal member, and an end portion on the atmosphere side of said seal member; and

a sleeve member to be mounted onto the inner member, said sleeve member having a flange portion protruding so as to face the atmosphere side of said seal member, and an outer cylindrical portion over-lapping with the projected portion of said seal member for covering an opening defined between the flange portion of said sleeve member and the end portion of said seal member,

the outer cylindrical portion of said sleeve member having a lip tip with a bend portion of axially over-lapping and inter-engaging with the projected portion of said seal member.

2. The sealing device according to claim 1, wherein said seal member is provided with a ring-shaped projection for slidably contacting said sleeve member on said atmosphere side thereof.

3. The sealing device according to claim 2, wherein said outer cylindrical portion of said seal member to be mounted onto said outer member is stepped by a greater diameter portion and a smaller diameter portion, said small diameter portion being provided with a projected portion.

4. The sealing device according to claim 3, wherein said smaller diameter portion of the seal member is provided with a recessed portion on the sealed liquid side of the projected portion.

5. A sealing device for sealing between concentric inner and outer members which are relatively rotatable with respect to one another, the sealing device comprising:

a seal member to be mounted onto said outer member, said seal member having a side facing radially outward towards the atmosphere, a recessed portion on said radially facing side of said seal member, an annular projected portion having a first rubber-like elastic member on said radially facing side of said seal member and protruding in a radial direction from a bottom portion of said recessed portion, a seal lip for sealing a liquid and an end portion on the atmosphere side of said seal member;

a sleeve member to be mounted onto said inner member, said sleeve member having an inner cylindrical portion, a flange portion protruding therefrom so as to face said end portion of said seal member and a second rubber-like elastic member covering at least an inner peripheral portion of said inner cylindrical portion, wherein said sleeve member slidably contacts with said seal lip of said seal member for sealing said liquid; and

an outer cylindrical member positioned over an opening formed between said flange portion of said sleeve member and said end portion of said seal member, said outer cylindrical member having a bend portion for forming a substantially narrow channel portion between said opening and the atmosphere, wherein an end portion of said outer cylindrical member extends into said recessed portion, whereby said outer cylindrical member is resiliently supported.