JP2002310305A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outer periphery rubber sealing device easy to assemble with superior assembling accuracy. SOLUTION: The sealing device comprises a cylindrical outer periphery portion formed of a rubber elastic body to be fitted to a housing cylindrical face and an inner periphery portion for sealing a shaft, wherein an annular stepped portion 6 is provided at the end of the outer periphery portion with its outer diameter set to be smaller than the inner diameter of the housing cylindrical face and protruded portions 8 are provided at plural cylindrical places on the annular stepped portion with its diameter larger than the inner diameter of a protruded housing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a sealing device. More specifically, the present invention relates to a sealing device such as an oil seal whose outer periphery is formed of rubber, which is easy to assemble and has excellent assembling accuracy.

[0002]

2. Description of the Related Art Conventionally, in a sealing device in which the outer peripheral surface of a metal ring is covered with rubber, the outer peripheral surface is a cylindrical surface,
The outer diameter is formed to be larger than the inner diameter of the housing in order to maintain sealing with the housing.

[0003]

When a sealing device having such a structure is mounted on a cylindrical surface of a housing, the sealing device cannot be held on the housing side depending on a mounting position such as a place where the cylindrical surface of the housing is not horizontal. there were. In such a case, after the sealing device is held by the press-fitting jig, a method of press-fitting into the housing cylindrical surface is adopted.
If the centering of the housing and the sealing device held by the press-fitting jig is not performed accurately, there is a possibility that oblique installation or galling may occur.

Therefore, as shown in FIG. 5, an annular step 6 having a diameter slightly larger than the cylindrical surface of the housing is provided on the distal end side of the outer peripheral portion of the sealing device, so that the sealing device is manually inserted into the cylindrical surface of the housing and positioned. After the holding, the press-fitting jig is pressed against the base end side of the sealing device to apply pressure to fit the fitting portion of the sealing device to a regular position on the cylindrical surface of the housing. Is uniformly in circumferential contact with the inner peripheral surface of the housing, so that the ratio of the change in the fitting force to the change in the fitting margin δ increases. (See FIG. 6) That is, if the fitting margin δ becomes slightly large, the fitting force is increased, and the insertion resistance is accordingly increased, and there is a possibility that the insertion cannot be performed by hand. When the fitting margin δ is small, there is a possibility that sufficient elasticity may not be maintained, and there is a possibility that galling due to oblique mounting may occur. For this reason, it has been necessary to strictly control the dimensional control of the inner diameter of the housing cylindrical surface and the outer diameter of the annular step portion of the sealing device.

An object of the present invention is to provide a sealing device that can be smoothly and accurately press-fitted into a housing cylindrical surface.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned drawbacks, the present invention provides a cylindrical outer peripheral portion formed of a rubber-like elastic body fitted on a cylindrical surface of a housing, and an inner peripheral portion for sealing a shaft. In the sealing device having a portion, an outer diameter is provided on the distal end side of the outer peripheral portion with an outer diameter set to be smaller than the inner diameter of the housing cylindrical surface, and the annular step has a projection having a diameter larger than the inner diameter of the housing. It is characterized in that a plurality of circumferential positions are provided.

Therefore, according to the present invention, an annular step portion having a smaller diameter than the cylindrical surface of the housing is formed on the distal end side of the outer peripheral portion of the sealing device, and a plurality of projections are provided on the annular step portion in a circumferential manner. With this configuration, the sealing device has an insertion resistance that can be pressed by hand, and after the insertion, the sealing device can be held on the housing cylindrical surface with a certain fitting force. Also, since the ratio of the change of the fitting force to the change of the fitting margin δ of the projection is small, even if there is a slight dimensional error between the inner diameter of the housing and the projection, the housing cannot be held on the cylindrical surface of the housing or cannot be pressed by hand. The problem described above can be prevented, and since there is no backlash in the housing cylindrical surface,
Centering of the sealing device can be performed with high precision, and galling due to oblique installation is prevented. Further, a structure for holding the sealing device on the press-fitting jig side is not required.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

FIG. 1 shows an embodiment of the present invention. FIG.
The sealing device has a reinforcing ring 4 having an L-shaped cross section, and a main lip 1 for sealing a shaft on an inner peripheral surface of the sealing device;
A dust lip 3 is provided on the opposite side of the main lip to prevent dust and dirt from entering, and a garter spring 2 is provided on the outer peripheral side of the main lip 1. The outer peripheral surface of the sealing device has an outer peripheral portion covered with a rubber member for sealing the cylindrical surface of the housing.

At the base end side (atmosphere side) of the outer peripheral portion of the sealing device,
A fitting portion 7 that fits into the housing cylindrical surface is formed. The fitting portion has an outer diameter larger than an inner diameter of the housing cylindrical surface in order to provide a predetermined fitting margin. And, on the tip side (sealing side) of the outer peripheral portion of the sealing device,
An annular step 6 having a smaller diameter than the cylindrical surface of the housing is formed. On the annular step 6, a projection 8 having a substantially circular cross section and substantially the same diameter as the fitting portion 7 is formed on the circumference. It is provided at intervals.

When the sealing device having the rubber portion on the outer periphery configured as described above is fitted to the cylindrical surface of the housing, first, the portion of the annular step portion 6 provided on the distal end side (sealing side) of the outer peripheral portion of the sealing device is removed. It is manually inserted into the housing cylindrical surface and positioned and held on the housing cylindrical surface. (See Fig. 2)
Only the projection 8 comes into contact with the inner peripheral surface of the housing, and the contact area between the cylindrical surface of the housing and the sealing device is reduced. Also, since the annular step absorbs the deformation of the projection,
Even if the fitting margin δ becomes slightly large, there is no significant change in the fitting force, so that there is no possibility that the fitting force cannot be inserted by hand. Also,
Since there is little change in the fitting force with respect to the fitting margin δ, the diameter of the projection can be set sufficiently larger than the inner diameter of the housing, so that the holding force after insertion can be sufficiently ensured, and the sealing device can be mounted on the housing cylinder. Positioning and holding can be stably and accurately performed on the surface.

Next, a press-fitting jig is pressed against the base end side of the sealing device which is positioned and held on the housing cylindrical surface by the protruding portion 8 and pressurized to fit the sealing device into a proper position on the housing cylindrical surface. Accordingly, even if pressure is applied to the sealing device from the inside of the housing such as hydraulic pressure, the sealing device does not easily fall off the cylindrical surface of the housing, and the sealing performance between the outer peripheral portion 5 of the sealing device and the cylindrical surface of the housing is improved. Secure.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited thereto, and various modifications can be made without departing from the spirit of the present invention. In the present embodiment, the protrusion is a substantially circular protrusion. However, the protrusion may be easily pressed into the housing by hand, and may be set to such a degree that it does not rattle or easily fall off after press-fitting. For example, the shape, outer diameter, number, etc., such as a triangular cross section shown in FIG. 4, can be variously modified.

[0014]

As described above, according to the present invention, the distal end of the outer peripheral portion of the sealing device is formed as an annular step having a smaller diameter than the cylindrical surface of the housing, and a projection is formed on the annular step.
The sealing device can be easily inserted into the cylindrical surface of the housing by hand, and after insertion, the sealing device can be stably and accurately positioned and held by the elastic restoring force of the projection.
In addition, since the ratio of the change in the fitting force to the change in the fitting allowance is small, the dimensional control of the sealing device can be made rough. Further, a structure for holding the sealing device on the press-fitting jig side becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a state where a sealing device of the present invention is fitted to a regular position on a cylindrical surface of a housing.

FIG. 2 is a partial cross-sectional view showing a state where the sealing device of the present invention is positioned and held on a cylindrical surface of a housing.

FIG. 3 is a partial perspective view of a sealing device showing one embodiment of the present invention.

FIG. 4 is a partial perspective view of a sealing device showing another embodiment of the present invention.

FIG. 5 is a partial sectional view showing a conventional sealing device.

FIG. 6 is an enlarged cross-sectional view around the annular step portion of the conventional sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main lip 2 Garter spring 3 Dust lip 4 Metal ring 5 Outer peripheral part 6 Annular step part 7 Fitting part 8 Projection part

Claims (1)

[Claims] 1. A sealing device having a cylindrical outer peripheral portion formed of a rubber-like elastic body fitted to a cylindrical surface of a housing and an inner peripheral portion for sealing a shaft. A sealing device comprising: an annular step portion whose diameter is set to be smaller than the inner diameter of the housing cylindrical surface; and a plurality of circumferential protrusions having a diameter larger than the inner diameter of the housing are provided at the annular step portion.