JP2002181200A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device of high reliability capable of preventing the generation of negative pressure and improving the sealing performance. SOLUTION: A dust lip 8b comprises a bottomed recessed part 8b1 opened to a space 10 side, a recognizing part 8b2 mounted on a part equivalent to a bottom part of the bottomed recessed part 8b1 at an atmospheric side O to recognize the bottom part from the atmospheric air side O, and a cut part 8b3 cut from the atmospheric air side O in the recognizing part 8b2, the cut part 8b3 is opened and closed in accordance with the pressure difference between the inside of the space 10 and the atmospheric air side O, and communicating the space 10 and the atmospheric side O in an opened state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device used for, for example, a shaft sealing portion of various devices.

[0002]

2. Description of the Related Art Conventionally, in a shaft sealing portion or the like of a device on which a sealing fluid acts, for example, as shown in a sectional configuration diagram of FIG. 3, an inner peripheral surface of a shaft hole 101a of a housing 101 and the shaft hole 101a. The annular gap 103 between the shaft 102 (rotating shaft) and the outer peripheral surface 102a of the shaft 102 is sealed.
Sealing device 100 (so-called oil seal) to prevent leakage of the sealing fluid from the air to the atmosphere side O as the anti-sealing side
Is provided.

The sealing device 100 has an annular shape, and has a substantially L-shaped cross section having an axial portion 105a on the outer peripheral side and a radial portion 105b bent inward from one end of the axial portion 105a (opposite the sealing fluid side 0). A reinforcement ring 105 having a U-shape is provided.

[0004] The seal portion 107 extends from the radial portion 105b of the reinforcing ring 105 to the sealing side M, and the shaft 10 serving as a sliding surface.
2, a main lip 107a in contact with the outer peripheral surface 102a,
And a dust lip 107b extending to the atmosphere side O. Reference numeral 108 denotes a spring that applies a tension to the main lip 107a.

[0005]

However, in the case of the above-described prior art, the following problems may occur.

The main lip 107a and dust lip 107b of the seal portion 107 and the outer peripheral surface 102a of the shaft 102
, A closed space 109 is formed, but a negative pressure may be generated in the closed space 109 as the shaft 102 rotates as a relative movement between the two members.

When a negative pressure is generated in the closed space 109, the main lip 107a and the dust lip 107b are attracted toward the closed space 109, respectively, so that the sliding resistance increases, and there is a possibility that the operational stability during sliding may be reduced. Was.

Therefore, conventionally, in order to prevent negative pressure, the inner diameter of the dust lip 107b is set to be smaller than the shaft diameter of the shaft 102 by 0.1 mm.
2 to 0.3 mm larger,
7b was provided with a through hole.

However, although these methods can prevent negative pressure, they are always in communication with the atmosphere side O, so that dust easily enters and the sealing function may be deteriorated. Is done.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a highly reliable sealing device which prevents generation of negative pressure and improves sealing performance. To provide.

[0011]

According to the present invention, there is provided a sealing device for sealing an annular gap between two members provided coaxially. A sealing device comprising: a main lip in sealing contact with one member; and a dust lip for preventing intrusion of dust from a non-sealing side, wherein a space is formed by the main lip, the dust lip, and the one member. In the above, the dust lip is provided in a bottomed concave portion that opens to the space side, and on the anti-sealing side, at a portion corresponding to the bottom of the bottomed concave portion, and identifies that it is the bottom from the non-sealing side. An identification portion to be provided, and a cut portion cut from the anti-sealing side in the identification portion, wherein the cut portion corresponds to a pressure difference between the space and the anti-sealing side. Open and close, in the open state, Characterized in that for communicating the space and the reflected sealing side.

With this configuration, when the negative pressure becomes a predetermined pressure and the dust lip is attracted to the space side and deforms, the cut portion is opened due to the pressure and the deformation of the dust lip, and the space to be cut is opened. When the negative pressure is suppressed, there is no deformation of the dust lip due to the negative pressure, and the cut portion is closed.

Therefore, unlike the conventional case, the main lip and the dust lip are attracted to the space side by the negative pressure, the sliding resistance increases, and the operation stability at the time of sliding does not decrease, and the negative pressure is reduced. In the suppressed state, the cut portion is in the closed state, so that dust does not invade and the sealing function does not deteriorate.

[0014]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, and relative arrangement thereof should be appropriately changed depending on the configuration of the apparatus to which the invention is applied and various conditions, and are not intended to limit the scope of the invention to the following embodiments.

FIG. 1 is a view for explaining the configuration of a sealing device 1 according to an embodiment of the present invention.

The sealing device 1 has a shaft hole 2a and a shaft (one member) 3 of a housing 2 as two members provided coaxially.
Sealing device 1 for sealing an annular gap 4 between the outer peripheral surface 3a and the outer peripheral surface 3a
(So-called oil seal), which is provided to prevent leakage of the sealing fluid from the sealing side M to the atmosphere side O as the anti-sealing side.

The sealing device 1 has an annular shape, and has an axial portion 5a on the outer peripheral side and one end of the axial portion 5a (atmospheric side O).
A reinforcing ring 5 having a radial portion 5b bent more inward and serving as a support portion; a fitting portion 7 and a sealing portion 8 formed by a rubber-like elastic body integrally formed so as to cover the periphery of the reinforcing ring 5; A radial portion 9 (a part of the seal portion 8) for connecting the mating portion 7 and the seal portion 8 is provided.

The reinforcing ring 5 is generally formed by press-molding a metal plate such as SPCC. However, the reinforcing ring 5 may be formed of an aluminum die-cast member or a resin member having a certain degree of rigidity. Is also possible.

The seal portion 8 includes a radial portion 9 of a rubber-like elastic body.
A main lip 8a extending to the sealing side M from the
And a dust lip 8b extending to the outside. Then, the main lip 8a, the dust lip 8b, and the shaft 3
A space 10 is formed by the outer peripheral surface 3a.

Here, as a characteristic configuration of the present invention, the dust lip 8b has a bottomed concave portion 8b1 that opens to the space 10 side.
And an identification portion 8b2 provided at a portion corresponding to the bottom of the bottomed concave portion 8b1 so that the bottom can be identified from the atmosphere side O.
And a cut portion 8b3 cut from the atmosphere side O in the identification portion 8b2. Dust lip 8b
It is preferable that the bottomed concave portion 8b1, the identification portion 8b2, and the cut portion 8b3 are provided in a uniform arrangement.

FIG. 2 is an enlarged view of a main part of the dust lip 8b, and FIGS. 2 (a), 2 (c) and 2 (e) are views showing an embodiment of the identification section 8b2. (D) and (f) are arrow views of FIGS. (A), (c) and (e), respectively.

The discriminating portion 8b2 allows the bottom of the bottomed recessed portion 8b1 to be easily identified from the atmosphere side O, that is, from the outside. The protrusion protrudes from the outside wall surface of the dust lip 8b on the atmosphere side O. (FIG. 2A,
(B)), a substantially circular convex (or concave) mark indicating a portion corresponding to the bottom may be formed on the outer wall surface of the dust lip 8b on the atmosphere side O (FIGS. 2C and 2D). ), A convex (or concave) mark indicating a line to be cut with a scalpel (FIGS. 2 (e) and (f)).
A combination of these may be used.

The cut portion 8b3 is located in the identification portion 8b2, and is cut in the manufacturing process. That is, it is cut at the same time as finishing the rubber-like elastic body in the manufacturing process, and is provided in the identification portion 8b2 which can be easily identified from the outside. The bottom of 8b1 can be cut, and the workability is excellent.

The cut portion 8b3 formed by scalping the rubber-like elastic body is substantially closed in the normal state where the negative pressure is suppressed.
When the dust lip 8b is deformed, the dust lip 8b is opened.

Here, the identification portion 8b2 and the cut portion 8b
Although it is conceivable to provide 3 on the sealing side M (inner wall surface) of the dust lip 8b, since the inner wall surface of the sealing side M of the dust lip 8b becomes a sliding surface, there is a possibility that the sealing performance may be affected. Also, cutting with a scalpel inside the annular seal portion 8 is inferior in workability. In the present embodiment, the outer wall of the dust lip 8b on the atmosphere side O is
Since the identification portion 8b2 and the cut portion 8b3 are provided, the sealing performance is not affected and the workability (workability of the rubber-like elastic body) is excellent.

Reference numeral 11 denotes a spring for applying a tension to the main lip 8a.

The sealing device 1 configured as described above seals the annular gap 4 between the shaft hole 2a of the housing 2 provided coaxially and the outer peripheral surface 3a of the shaft 3. With the relative movement between the shaft 10 and the shaft 3, a negative pressure may be generated in the space 10.

In the present embodiment, however, the dust lip 8b has a concave portion 8b1 having a bottom and a cut portion 8b3.
Is provided, when the negative pressure reaches a predetermined pressure, the cut portion 8b3 opens to allow the space 10 to communicate with the atmosphere side O, or when the negative pressure reaches a predetermined pressure, the dust lip 8b Is deformed by being attracted to the space 10 side, and the cut portion 8 is deformed along with the deformation of the dust lip 8b.
By opening b3, the space 10 and the atmosphere side O can be communicated. When the negative pressure can be suppressed, the dust lip 8b is not deformed by the negative pressure, and the cut portion 8b3 is closed.

Therefore, unlike the related art, the main lip 8a and the dust lip 8b are attracted to the space 10 side by the negative pressure, so that the sliding resistance increases, and the operation stability during sliding does not decrease, and In the state where the negative pressure is suppressed, since the cut portion 8b3 is in the closed state, dust does not invade and the sealing function does not deteriorate.

That is, it is possible to prevent the negative pressure and the intrusion of dust, and it is possible to provide a highly reliable sealing device having improved sealing performance.

Further, the bottomed concave portion 8b1, the identification portion 8b2, and the cut portion 8 provided on the dust lip 8b are arranged equally.
By appropriately setting the number of b3 and the thickness of the bottom of the bottomed concave portion 8b1, it is possible to preferably prevent the negative pressure and the dust from entering.

[0032]

As described above, according to the present invention,
The cut portion opens and closes according to the pressure difference between the inside of the space and the anti-sealing side, and in an open state, connects the space and the anti-sealing side to prevent negative pressure and prevent dust from entering. Can be prevented, and a highly reliable sealing device with improved sealing performance can be provided.

That is, unlike the conventional case, the main lip and the dust lip are attracted to the space side by the negative pressure, the sliding resistance is increased, the operation stability during sliding is not reduced, and the negative pressure is reduced. In the suppressed state, the cut portion is in the closed state, so that dust does not invade and the sealing function does not deteriorate.

Further, the cut portion cut from the non-sealing side is provided in the identification portion which can be identified as the bottom of the bottomed concave portion from the non-sealing side, so that it can be easily and externally applied. It can be cut reliably and has excellent workability (workability).

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration explanatory view of a sealing device according to an embodiment.

FIG. 2 is a diagram illustrating a main part of the sealing device according to the embodiment;

FIG. 3 is an explanatory view of a cross-sectional configuration of a sealing device according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing device 2 Housing 2a Shaft hole 3 Shaft 3a Outer peripheral surface 4 Annular gap 5 Reinforcement ring 5a Axial portion 5b Radial portion 7 Fitting portion 8 Seal portion 8a Main lip 8b Dustrip 8b1 Bottom concave portion 8b2 Identification portion 8b3 Cut part 9 Radial part 10 Space 11 Spring M Sealed side O Atmospheric side (anti-sealed side)

Claims (1)

[Claims] 1. A sealing device for sealing an annular gap between two members provided coaxially, wherein a main lip sealingly contacts one of the two members, and a dust of dust from a non-sealing side. A dust lip for preventing intrusion; and a sealing device in which a space is formed by the main lip, the dust lip, and the one member, wherein the dust lip has a bottomed concave portion that opens to the space side, An identification portion that is provided on a portion corresponding to the bottom of the bottomed concave portion on the anti-sealing side, and that can be identified as the bottom from the anti-sealing side; and an identification portion cut from the anti-sealing side in the identification portion. A cut portion, wherein the cut portion opens and closes in accordance with a pressure difference between the inside of the space and the anti-sealing side, and communicates the space with the anti-sealing side in an open state. Characterized by sealing Location.