JP2000035136A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the starting friction while restricting the occurrence of noise by providing plural separate recessed parts in a surface of a seal lip part for abutting on the shaft surface in the only case where the deformed variable exceeds the predetermined value. SOLUTION: A seal lip 4 is provided with separate plural recessed parts 5 in an area S except for an area T near a tip of a flat surface extended from the tip of the lip 4 to the atmosphere side A. Dimension, number, arrangement and shape of the recessed part 5 is set in response to the material of the seal, pressure and kinds of the sealing fluid, and kinds of the lubricating material. When the deformed variable exceeds the predetermined value, an overlapped area is generated between a surface contact area V in relation to the shaft surface and the area S provided with the recessed part 5. Even in the case where the sealing device 1 is moved for reciprocation after the sealing device 1 is left for a long time in this condition, occurrence of noise is restricted by the lubricating material held in the recessed part 5 so as to improve the starting friction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device for sealing a sealing fluid, particularly for a reciprocating motion.

[0002]

2. Description of the Related Art Conventionally, this type of sealing device has
For example, it is applied to gas stays and the like.

Hereinafter, description will be made with reference to FIGS. 5 and 6.

FIG. 5 is a schematic view showing a state in which the sealing device is applied to a gas stay, and FIG. 6 is a schematic sectional view of a conventional sealing device.

[0005] As shown in FIG. 5, in the gas stay, the piston P is reciprocated by reciprocating the shaft 10 supported by the bush B in the cylinder 30. The fluid on the fluid (OIL + nitrogen gas) side O is prevented from leaking to the atmosphere side A.

The sealing device 1 prevents leakage of a sealing fluid by sealing the inner periphery of the cylinder 30 and the outer periphery of the shaft 10. In particular, the structure of the seal lip that slides on the outer periphery of the shaft 10 is as follows. It plays an important role in the sealing performance, but as the configuration of this seal lip,
Conventionally, there were approximately three types shown in FIG.

Hereinafter, a conventional sealing device will be described with reference to FIG.

First, the sealing device 100 shown in FIG.
In the most basic configuration, the seal lip 101 is a so-called female cut plane lip or a mold lip, and is formed by cutting or by molding.

The seal lip 101 is made of an elastic member, and slides on the shaft 10 to seal while following the eccentricity of the shaft 10.

The sealing lip 201 of the sealing device 200 shown in FIG. 2B has a configuration shown in FIG. 2A, and further has an annular projection (parallel or cut projection) 202 on the surface of the lip.
In which the ability of retaining oil on the surface is improved.

The sealing lip 301 of the sealing device 300 shown in FIG. 3C is obtained by coating a resin (PTFE or the like) 302 on the lip surface shown in FIG. It is intended.

[0012]

However, in the case of the above-described prior art, the following problems have occurred.

In the case of the above-described sealing device, the seal lip is slidably contacted with the shaft surface while deforming due to frictional resistance received from the shaft surface when moving relative to the shaft.

Here, when the sealing device moves toward the atmosphere relative to the shaft (when the above-described gas stay is applied, the shaft moves to the sealing fluid side while the sealing device is still stationary), the sealing lip is It is deformed to be stretched by being pulled toward the sealed fluid side.

At this time, the seal lip is in a state where the flat portion extending from the substantially edge portion of the tip to the atmosphere side is in planar contact with the shaft surface.

Therefore, the larger the amount of deformation of the seal lip, the larger the area of contact with the shaft surface.

Here, conventionally, when the sealing lip is deformed as described above and left in a fully extended state, and then the reciprocating motion of the sealing device is started, an abnormal noise may be generated.

This is because the oil on the surface of the lip squeezes out during the standing, and the respective contact surfaces become dry. It is believed that sound is generated.

In particular, in the structure shown in FIG. 6A, if the seal lip is left fully extended,
The contact surface was completely dried, and the noise was most likely to be generated, and the sound tended to be loud.

In the configuration shown in FIG. 6 (B), when the seal lip is fully extended and left to stand, the annular projection provided on the lip surface has a certain oil retaining ability. To some extent, noise generation was suppressed,
Due to its configuration, the holding capacity is still insufficient, and when the standing period is prolonged, abnormal noise is generated.

In the configuration shown in FIG. 6 (C), even if the contact surface becomes dry when the seal lip is left extended, the coefficient of friction is low due to the resin coating. The generation of abnormal noise was suppressed even when sliding between dry surfaces.

However, such a resin coating is worn away due to long-term use, so that such an effect is lost. Further, a step for applying the resin coating is required, and the cost is increased. Had been connected.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a sealing device which suppresses generation of abnormal noise and improves starting friction. is there.

[0024]

According to the present invention, there is provided a seal lip which extends toward a sealing fluid side and slides on a shaft surface, and is relatively fixed to the shaft. In a sealing device that is arranged to be reciprocable in the axial direction, the seal lip surface portion that comes into contact with the shaft surface only when the amount of deformation of the seal lip exceeds a predetermined amount due to relative movement to the side opposite to the sealing fluid. Characterized in that a plurality of recesses are provided.

Therefore, even if the seal lip is left in a state where the amount of deformation of the seal lip becomes a predetermined value or more due to the relative movement to the side opposite to the sealing fluid, a plurality of independent concave portions provided on the surface of the lip. Can hold a sealing fluid, a lubricant, and the like.

[0026]

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, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

A sealing device according to an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic partial cutaway view of a sealing device according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram showing a mounted state of the sealing device according to the embodiment of the present invention.
FIG. 3 is a schematic diagram illustrating an operation state of the sealing device according to the embodiment of the present invention.

As described above, the sealing device according to the embodiment of the present invention is applied to a gas stay or the like as shown in FIG.

That is, when the shaft 10 supported by the bush B reciprocates in the cylinder 30, the piston P
Are reciprocated so that the sealing device 1 does not leak the sealing fluid (OIL + nitrogen gas) O to the atmosphere side.

The sealing device 1 prevents leakage of the sealed fluid O by sealing the inner periphery of the cylinder 30 and the outer periphery of the shaft 10.

As shown in FIG. 1, a sealing device 1 according to the present embodiment generally includes a metal ring 2 and an outer peripheral lip 3 and a seal lip 4 which are integrally formed with the metal ring 2. Be composed.

The sealing device 1 constructed as described above
Is mounted in an annular gap between the housing 20 and the shaft 10 so that the outer peripheral lip 3 seals the inner periphery of the housing 20 and the seal lip 4 seals the outer periphery of the shaft 10 so that the sealing fluid side Seal between O and atmosphere side A.

Since the sealing device 1 shown in FIGS. 1 and 2 has the metal ring 2, the housing 20 is divided into a sealed fluid side housing 20a and an atmosphere side housing 20b. As a configuration, the sealing device 1 can be mounted.

Next, the configuration and the like of the seal lip which is a feature of the present embodiment will be described in detail.

In the seal lip 4 of the present embodiment, a plurality of independent concave portions (dimples) are provided in a region S excluding a region T near the front end of a plane extending from the front end of the lip toward the atmosphere side A. 5 are provided.

The size, number, arrangement position, shape, and the like of the recesses 5 may be appropriately set according to the material of the seal, the pressure of the sealing fluid, the type of the sealing fluid, the type of the lubricant (such as grease), and the like. .

The use state of the thus constructed sealing device will be described with particular reference to FIG.

FIG. 3A shows a case where the amount of deformation of the seal lip 4 is small, and the surface contact area U on the shaft surface is shown.
Does not overlap with the region S where the concave portion 5 is provided.

Then, the sealing device 1 moves to the atmosphere side A relative to the shaft 10 (when the above-described gas stay is applied, the shaft 10 moves to the sealing fluid side O while the sealing device 1 is still stationary). FIG. 3B shows a state in which the seal lip 4 is deformed so as to be pulled and extended toward the sealing fluid side O.

As shown in FIG. 3B, when the amount of deformation of the seal lip 4 exceeds a predetermined value, the seal lip 4 overlaps the surface contact region V with the shaft surface and the region S where the concave portion 5 is provided. An area will result.

In this state, a lubricant such as oil or grease can be held in the plurality of recesses 5 for a long time.

Therefore, after leaving the sealing device 1 for a long time in the state as shown in FIG.
, The generation of abnormal noise can be suppressed and the starting friction can be improved by the lubricant or the like held in the concave portion 5.

The recesses 5 are provided independently of each other.
As shown in FIG. 6 (B) in the above prior art, since the structure is not like a continuous groove, a lubricant such as oil does not easily escape, and the volume of the holding portion can be sufficiently ensured. Excellent function.

Further, as compared with the case of resin coating as shown in FIG. 6B, the degree of deterioration of the function due to abrasion is small (appropriate adjustment can be easily made by the depth of the concave portion, etc.). ) So it can last longer
Excellent quality and durability.

(Other Embodiments) In the above description,
Although the case of a sealing device having a metal ring has been described as an example,
A configuration without a metal ring may be employed. For example, the configuration shown in FIG. 4 may be employed.

In the sealing device 11 shown in FIG. 4, the outer peripheral lip 31 and the seal lip 41 are constituted only by the elastic member, and the concave portion 51 is provided at a predetermined position of the seal lip 41 as described above.

In such a configuration, the housing on which the sealing device 11 is mounted can be mounted without the above-described two-part structure.

The functions and the like are the same as those described above, and a description thereof will not be repeated.

The basic structure of the sealing device is not limited to the structure shown in FIGS. 1 and 4 and the like. If the sealing device has a known seal lip, the surface of the seal lip is formed as described above. What is necessary is just to provide a concave part.

[0051]

As described above, a plurality of independent seal lip surface portions are brought into contact with the shaft surface only when the amount of deformation of the seal lip exceeds a predetermined value due to the relative movement to the side opposite to the sealing fluid. Since the concave portion is provided, even if the seal lip is deformed to a predetermined amount or more due to relative movement to the side opposite to the sealing fluid, even if the seal lip is left alone, a plurality of independent lip surface portions are provided. Since the recess can hold a sealing fluid, a lubricating material, or the like, generation of abnormal noise can be suppressed, and starting friction can be improved.

[Brief description of the drawings]

FIG. 1 is a partial cutaway view of a schematic configuration of a sealing device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a mounted state of the sealing device according to the embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating an operation state of the sealing device according to the embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a sealing device according to another embodiment of the present invention.

FIG. 5 is a schematic diagram showing a state in which the sealing device is applied to a gas stay.

FIG. 6 is a schematic sectional view of a sealing device according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11 Sealing device 2 Metal ring 3, 31 Outer lip 4, 41 Seal lip 5, 51 Depression 10 Shaft 20 Housing 30 Cylinder

Claims (1)

[Claims] 1. A sealing device having a sealing lip extending toward a sealing fluid side and slidably in contact with a shaft surface, wherein the sealing device is disposed so as to be reciprocally movable in an axial direction relative to the shaft. A sealing device, wherein a plurality of independent concave portions are provided in a surface portion of a seal lip that comes into contact with a shaft surface only when a deformation amount of the seal lip becomes equal to or more than a predetermined amount due to a relative movement to a side.