JPH08291868A - Oil seal - Google Patents

Abstract

PURPOSE: To prevent generation of rust when slurry splashes an exposed part in a metal reinforcement ring and peeling of a dust lip so as to improve durability and a life of an oil seal. CONSTITUTION: An extension part 8a in a dust lip 8 is arranged in a part of a section in which an exposed part 6a in a metal reinforcement ring 6 is brought into contact with a stopper wall member 9, while in the dust lip extension part 8a, one or more circular projection 8b is arranged on the surface on the side which is brought into contact with the stopper wall member 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal for sealing liquid or gas inside a machine so as not to leak to the outside, and water or dust from the outside to the inside of the machine.

[0002]

2. Description of the Related Art FIG. 2 shows the structure of a conventional oil seal. The oil seal 1 is used in the power steering device and is provided between the input shaft 2 and the housing 3,
It is composed of a rubber lip holding portion 4 and a mounting fitting portion 5, and a metal reinforcing ring 6 having an L-shaped cross section integrally formed from the mounting fitting portion 5 toward the lip holding portion 4. Lip holder 4
Has a main lip 7 on the inner side in the axial direction and a dust lip 8 on the outer side, and makes elastic contact with the input shaft 2 in a state of being attached to the housing 3. The mounting fitting portion 5 is fitted to the oil seal mounting portion 3a of the housing 3, and the exposed portion 6a of the metal reinforcing ring 6 on the axially outer side abuts on the stopper wall member 9 of the housing 3 to move in the direction of arrow A. Supports internal pressure. Reference numeral 10 is a spring for pressing the main lip 7 against the input shaft 2.

The oil in the housing 3 is prevented from flowing out by the main lip 7 of the oil seal 1, and the water and dust on the outside are prevented from flowing into the housing 3 by the dust lip 8.

[0004]

However, in the above-mentioned conventional oil seal, since the exposed portion 6a of the metal reinforcing ring 6 exists on the axially outer side of the oil seal 1, muddy water is exposed to the exposed portion 6a from the outside. In this case, rust occurs. When this rust progresses, peeling occurs on the adhesion surface 6b with the dust lip 8. Therefore, even if the dust lip 8 has good muddy water resistance and the main lip 7 has good sealing performance, the peeling of the dust lip 8 makes it impossible for the dust lip 8 to maintain its performance, and muddy water may enter. There is a risk that the durability performance and the life of the oil seal 1 itself may be reduced due to the reduction of the pressure resistance performance. The present invention solves such conventional problems, and an object of the present invention is to provide an oil seal with improved durability and life.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an extension of a dust lip in a part of a portion where an exposed portion of a metal reinforcing ring contacts a stopper wall member. In addition, one or more annular protrusions are provided on the surface of the extension of the dust strip that is in contact with the stopper wall member.

[0006]

Therefore, according to the present invention, since the extension portion of the dust lip is interposed in a part of the portion where the exposed portion of the metal reinforcing ring contacts the stopper wall member, the exposed portion of the metal reinforcing ring is directly exposed to the outside. Since it is not exposed to muddy water or the like, the occurrence of rust or peeling is prevented, and the durability and life of the oil seal can be improved.

[0007]

FIG. 1 shows the configuration of an embodiment of the present invention, and FIG.
Since it has almost the same configuration as the above, the same reference numerals are given to the similar elements. That is, the oil seal 1
Provided between the input shaft 2 and the housing 3, the lip holding portion 4 and the mounting fitting portion 5 made of rubber, and having an L-shaped cross section integrally formed from the mounting fitting portion 5 toward the lip holding portion 4. And a metal reinforcing ring 6. The lip holding portion 4 has a main lip 7 on the inner side in the axial direction and a dust lip 8 on the outer side, and is elastically contacted with the input shaft 2 in a state of being attached to the housing 3. The mounting fitting portion 5 is fitted to the oil seal mounting portion 3a of the housing 3, and the exposed portion 6a of the metal reinforcing ring 6 on the outer side in the axial direction abuts the stopper wall member 9 of the housing 3 to cause an internal pressure in the direction of arrow A. Is supporting. The stopper wall member 9 may be a separate member fixed to the housing 3. Reference numeral 10 is a spring for pressing the main lip 7 against the input shaft 2.

The exposed portion 6a of the metal reinforcing ring 6 is bent so as to be slightly recessed inward in the axial direction from the middle thereof to form a gap with the stopper wall member 9, and the exposed portion of the metal reinforcing ring 6 is filled with the gap. 6a so as to form the same side surface as the surface,
An extension 8a is formed on the dust lip 8. Further, one or more annular protrusions 8b are formed on the surface of the extension portion 8a on the side that contacts the stopper wall member 9. In addition,
The entire exposed portion 6a of the metal reinforcing ring 6 is replaced with the dust lip extension portion 8
When covered with a, the oil seal 1 moves in the axial direction due to internal pressure fluctuations, causing problems such as oil leakage from the mounting fitting portion 5, so that the extension portion 8a is formed in a part of the metal reinforcing ring exposed portion 6a. The extension 8a and the metal reinforcing ring exposed portion 6 should be provided.
It is assumed that a contacts the stopper wall member 9 together.

Since the oil seal 1 of this embodiment is constructed as described above, when it is fixed to the housing 3, the stopper wall member 9 of the housing 3 has a metal reinforcing ring exposed portion 6a and a dust lip. 8 will be in contact with the extended portion 8a of the metal reinforcing ring 8 and the exposed metal reinforcing ring 6a will not be directly exposed to muddy water or the like, and the metal reinforcing ring exposed portion 6a will be rusted or the dust lip 8 will be bonded. No peeling occurs on the surface. Further, when the metal reinforcing ring exposed portion 6a and the dust lip extension portion 8a are in uniform contact with the stopper wall member 9, there is no problem, but when they are in non-uniform contact, muddy water or the like enters from that portion. In this embodiment, there is a possibility that there is a possibility that 1
Since the annular projection 8b is provided so that the annular projection 8b always contacts the stopper wall member 9 even if there is a slight gap, it is possible to reliably prevent the entry of muddy water or the like.

In the above embodiment, the metal reinforcing ring exposed portion 6a is bent to form a gap for interposing the dust lip extended portion 8a. However, without bending the metal reinforcing ring exposed portion 6a, the gap is formed from the beginning. It may be formed into a shape having such a gap.

[0011]

As described above, according to the present invention, the extension portion of the dust lip is interposed in a part of the portion where the exposed portion of the metal reinforcing ring contacts the stopper wall member. The exposed portion of the ring is not directly exposed to external muddy water or the like, the occurrence of rust and peeling is prevented, and the durability and life of the oil seal can be improved. Further, by providing one or more annular protrusions on the extension portion of the dust lip, even if the surface accuracy between the exposed portion of the metal reinforcing ring that contacts the stopper wall member and the extension portion of the dust lip is slightly poor, the extension of the dust lip is performed. The part can be reliably brought into contact with the stopper wall member.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an oil seal showing an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing an example of a conventional oil seal.

[Explanation of symbols]

 1 Oil seal 2 Input shaft 3 Housing 4 Lip holding part 5 Mounting fitting part 6 Metal reinforcement ring 6a Exposed part 7 Main lip 8 Dust lip 8a Extension part 8b Annular protrusion 9 Stopper wall member 10 Spring

Claims (2)

[Claims] 1. An oil seal comprising a main lip on the inner side in the axial direction and a dust lip on the outer side, the metal reinforcing ring exposed on the outer side in the axial direction being fixed to the housing in a state of being in contact with a stopper wall member of the housing. An oil seal, wherein an extension portion of the dust lip is interposed in a part of a portion where the exposed portion of the reinforcing ring contacts the stopper wall member. 2. The oil seal according to claim 1, wherein one or more annular protrusions are provided on the surface of the extension portion of the dust lip that is in contact with the stopper wall member.