JPH10246338A - Oil seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil seal with high reliability and simple structure which can surely prevent oil leakage. SOLUTION: An oil seal 4 which is fit to the through section of a housing 1 of a rotary shaft 2 comprises a seal ring 5b provided on the inner periphery thereof with a seal lip 5c fitted securely into a through hole 3 of the housing 1 and expanding its diameter as it goes to the tip, and a slinger 6 provided with a flange 6b having a sealing surface 6c formed at the outside thereof in sliding contact with the inside surface of the tip of the seal lip 5c at the inner end of a cylindrical section 6a fitted to the rotary shaft 2 thereof. Further, by forming an annular oil reservoir 6f at the outer side of the flange 6b by provision of an oil dam 6e protruding against the lip seal 5c on the surface of the cylindrical section 6a, oil leakage can surely be prevented, naturally when the rotary shaft 2 is in operation but even when the shaft 2 is out of operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal, and more particularly, to an oil seal capable of accurately preventing oil leakage from a portion of a rotary shaft through a housing.

[0002]

2. Description of the Related Art A conventional oil seal used for avoiding oil leakage from a rotating shaft penetrating portion of a housing is disclosed, for example, in "Automotive Diesel Engine" issued by Sankaido Co., Ltd. on July 30, 1977. 15th
As shown on page 2, a slinger is provided on the rotating shaft, and a seal lip is slid on the outer surface (atmosphere side) of the slinger, thereby applying a centrifugal force to the oil passing through the contact surface with the seal lip. It may be pulled back inside the housing.

However, even when the slinger is provided in this manner, when the rotating shaft stops, the return action by the centrifugal force cannot be performed. There is a possibility that minute oil adhering to the surface leaks to the outside along the surface of the cylindrical portion of the slinger.

In order to prevent such oil leakage, a secondary slinger is provided outside the main slinger as shown in Japanese Utility Model Laid-Open Publication No. 1-168061.
A ring-shaped projection protruding between both slinger is provided on the inner peripheral surface of the seal ring, but in this case, there is a problem that the structure of the oil seal becomes complicated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to accurately prevent oil leakage not only during rotation of a rotating shaft but also when the rotating shaft is stopped. It is an object of the present invention to provide a highly reliable oil seal having a simple structure.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention expands an oil seal attached to a portion of a rotary shaft through a housing through a through-hole provided in the housing and extends toward an end. A seal ring provided on the inner periphery with a sealing lip having a diameter, and a slinger provided on an inner end of a cylindrical portion fitted on the rotary shaft, and a flange formed on the outside with a sealing surface slidably in contact with the inner surface of the tip of the sealing lip. It consists of. An oil dam protruding toward the seal lip is provided on the surface of the cylindrical portion to form an annular oil reservoir outside the flange.

According to the present invention, an oil dam can be formed by bulging a cylindrical portion of a slinger or attaching an O-ring to the cylindrical portion of the slinger.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of an oil seal according to the present invention, in which an oil seal 4 is attached to a through hole 3 of a rotating shaft 2 provided in a housing 1. The oil seal 4 includes a seal ring 5 fitted to the through hole 3 and a slinger 6 fitted to the rotating shaft 2.

The seal ring 5 includes an outer ring 5b having a packing 5a in close contact with the through hole 3 mounted on the outer peripheral surface thereof, and a seal lip 5 integrally formed on the inner periphery of the outer ring 5b.
c.

The seal lip 5c constitutes a so-called outward seal lip that projects toward the inside of the housing 1 while gradually increasing in diameter toward the tip. Reference numeral 5d denotes an auxiliary lip for forming a guide groove 5e on the inner peripheral surface of the base of the seal lip 5c, and receives the oil adhering to the inner peripheral surface of the seal lip 5c and flowing down. 5f is a dust seal for preventing foreign matter from entering from outside.

On the other hand, the slinger 6 has a cylindrical portion 6a fitted to the rotating shaft 2 and a flange 6b bent from the inner end of the cylindrical portion 6a in the outer peripheral direction. ) Is a seal surface 6c that slides on the seal lip 5c. 6d is a packing for sealing the fitting gap between the cylindrical portion 6a and the rotary shaft 2.

In this embodiment, the oil dam 6e is formed by bulging the cylindrical portion 6a of the slinger 6 into a ring shape at a position facing the base of the seal lip 5c, thereby forming an annular shape outside the flange 6b. The oil reservoir 6f is formed.

In the oil seal having such a configuration,
When the rotary shaft 2 is rotating, the small amount of oil that has passed through the sliding contact gap with the seal lip 5c and has lubricated the seal lip 5c is generated by the flange 6b of the slinger 6 rotating together with the rotary shaft 2. Under the centrifugal force, it is returned into the housing 1 again.

On the other hand, when the rotating shaft 2 is stopped, since the centrifugal force is not applied by the flange 6b, the sealing surface 6d of the flange 6c is located above the center of the rotating shaft 2.
The oil adhering to the dust seal 7 tends to leak through the gap of the dust seal 7 through the cylindrical portion 6a. However, since the oil reservoir 6f formed by the oil dam 6e is formed in the cylindrical portion 6a, the oil flowing down along the sealing surface 6c of the flange 6b is blocked by the oil dam 6e and collected in the oil reservoir 6f. The oil sump 6f flows in the circumferential direction and drops on the surface of the seal lip 5c.

At this time, the oil dam 6e is formed to face the seal lip 5c whose diameter increases toward the tip. Accordingly, the oil that has flowed in the oil sump 6f in the circumferential direction and dropped has returned along the surface of the seal lip 5c and into the housing 1 through the contact portion with the lower seal surface 6c.

The oil adhering to the surface of the seal lip 5c above the center of the rotary shaft 2 is guided by the guide groove 5e and drops into the oil sump 6f, and goes through the same process as described above. Or the seal lip 5c below the center of the rotating shaft 2.
There is no concern that oil leakage will occur as in the prior art, since the oil is temporarily stored between the seal and the sealing surface 6c.

In the above embodiment, a part of the cylindrical portion 6a of the slinger 6 is bulged into a ring shape to form an oil dam 6e.
Although the manufacturing cost is prevented from increasing due to an increase in the number of parts, the oil dam 6e
Can also be configured.

FIG. 2 is a sectional view showing another embodiment of an oil seal according to the present invention. In this embodiment, an oil dam is formed by fitting an O-ring 6g to a cylindrical portion 6a of a slinger 6. doing. Therefore, in the case of this embodiment, there is an advantage that an oil dam having a desired height can be easily formed while using the O-ring 6g, which is a general-purpose component, and the molding process of the slinger 6 can be simplified. .

[0019]

As is apparent from the above description, according to the present invention, an oil dam is provided on the surface of the cylindrical portion of the slinger so as to protrude toward the seal lip which expands in diameter toward the tip end, and an annular oil sump is provided outside the flange. Is formed to prevent oil from flowing out, so that oil leakage can be accurately prevented not only during rotation of the rotating shaft but also while the rotating shaft is stopped. In addition, since an oil dam is provided on the cylindrical portion of the slinger and a ring-shaped oil reservoir is formed outside the flange, the desired purpose can be achieved, but the production cost of the oil seal increases. I don't have to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an oil seal according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the oil seal according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 housing 2 rotating shaft 3 through hole 4 oil seal 5 seal ring 5a packing 5b outer ring 5c seal lip 5d auxiliary lip 5e guide groove 5f dust seal 6 slinger 6a cylindrical portion 6b flange 6c seal surface 6d packing 6e oil dam 6g O oil ring 6g

Claims (3)

[Claims] 1. An oil seal attached to a housing penetrating portion of a rotary shaft, the seal ring having a seal lip provided on an inner periphery thereof, the seal lip being fitted into a through hole provided in the housing and increasing in diameter toward a tip end. An oil dam that includes a slinger provided at an inner end of a cylindrical portion fitted to the rotary shaft and having a flange formed on the outer side of the seal surface in sliding contact with the inner surface of the distal end of the seal lip, and protruding toward the seal lip. An oil seal, wherein an annular oil reservoir is formed on a surface of the cylindrical portion and outside a flange. 2. The oil seal according to claim 1, wherein an oil dam is formed by bulging a cylindrical portion of the slinger. 3. The oil seal according to claim 1, wherein an O-ring is mounted on a cylindrical portion of the slinger to form an oil dam.