JPH08200514A - Sealing device - Google Patents

Abstract

PURPOSE: To provide a sealing device which is abutted on the sliding surface with the prescribed abutting area by the friction force irrespective of the pressure fluctuation of the sealed fluid with a simple constitution, provided with the stable working characteristics, reduced in the friction at the tip part of the lip of a sealing member, durable and excellent in the sealability such as the eccentricity followability. CONSTITUTION: An annular projecting bar 5f is provided on an abutting surface 5d with a holding member 4 of a sealing member 5, the holding member 4 is provided with an annular recessed groove 4f to be fitted to the projecting bar 5f on an abutting surface 4a with the sealing member 5, and this annular recessed groove 4f is provided with a marginal region 6 where the sealing member 5 can be deformed to the holding member 4 side under the pressure of the sealed fluid L1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating sealing device that seals a gap between a shaft and a housing member that relatively reciprocates by the pressure of a sealing fluid.

[0002]

2. Description of the Related Art As a conventional reciprocating sealing device of this type, there is one shown in FIG. 5, for example.

FIG. 5A shows a reciprocating oil seal 100.
FIG. The shaft 10 is provided on the inner circumference of the housing 101.
A rod guide 103 for supporting 2 is fitted, and a seal member holding portion 103a axially extending to the sealing fluid L101 side is provided on the inner periphery of the rod guide 103 on the sealing fluid L101 side.
Is provided, and the seal member holding portion 103a and the housing 1 are provided.
A seal member 105 made of a rubber-like elastic body is provided between the inner periphery of 01 and the inner periphery of 01 to abut the sliding surface of the shaft 102.

The rod guide 10 of the seal member 105
3, the shape of the seal member 105 is held on the contact surface in the radial direction with the seal member holding portion 103a and the housing 1.
The reinforcing ring 104 for fitting and fixing the seal member 105 is integrally formed with the inner circumference of the inner ring 01.

In this reciprocating oil seal 100, a piston member (not shown) connected to the shaft 102 operates in the axial direction in the housing 101 by the pressure fluctuation of the sealing fluid L101, and the seal member 105 slides the shaft 102. The moving surface and the lip tip portion 106 are in contact with each other to seal the sealing fluid L101. When the pressure of the sealing fluid L101 increases, the lip tip portion 106 is pressed, and the tightening force indicated by the arrow A102 increases.

FIG. 5B shows another conventional example,
FIG. 3 is a cross-sectional explanatory view of the reciprocating oil seal 200, and shows a housing 201 and the housing 2 as main components.
01 is composed of a reciprocating oil seal 200 and a shaft 202.
The reciprocating oil seal 200 seals the sealing fluid L201 with the sliding surface of the shaft.

This reciprocating oil seal 200 is provided with seal members 205 and 206 and holding members 203 and 207 which hold the two seal members so as to sandwich them from both sides in the axial direction. 207 has a communication hole 208 for communicating the sealing fluid L201 with the sealing member 206 and a pressure chamber 208a.
When 1 becomes high pressure, the seal member 20 is
Press 6.

The seal member 206 pressed by the sealing fluid L201 is in contact with the seal member 205 at a contact portion 206a.
The seal member 205 is pressed in the direction of the shaft 202 with the seal member 205 so that the contact surface 205a with the shaft 202 is indicated by the arrow A202.
Will give the tension shown in.

The reciprocating oil seal 200 is provided with a seal member 204 for sealing the atmosphere side, a connecting member 203a for connecting the seal member 204 to the holding member 203, and the reciprocating oil seal 200 for a predetermined housing 201. Fixing rings 209 and 21 for fixing in position
There is 0.

[0010]

However, in the conventional example shown in FIG. 5 described above, in FIG. 5A, the seal member holding portion 103a of the rod guide 103 changes the pressure of the sealing fluid L101 of the seal member 105. Although it acts to suppress the bending and deformation associated with the
01 pressure fluctuation causes the shaft 102 of the lip tip 106 to
The contact force and the contact area with respect to the sliding surface change, the frictional force with the sliding surface changes, and at the same time, the wear resistance is inferior, and there is a problem in operating characteristics and durability. Further, in the configuration of the reciprocating oil seal 100, the tightening margin of the lip tip portion 106 cannot be made large, and the ability to follow the eccentricity with respect to the shaft 102 is poor.

The reciprocating oil seal 200 shown in FIG. 5B solves some of the problems of the reciprocating oil seal 100, but as described above, it has a very complicated structure. And the price is high. Then, in particular, when the sealing fluid has a high pressure, the pressing force A202 of the contact surface 205a of the seal member 205 with respect to the shaft 202 increases, and the frictional resistance becomes very large. Further, when used at a low temperature, the sealing member 206 becomes hard and the sealing member 205 that directly abuts the shaft 202 cannot be pressed, resulting in poor sealing performance.

The present invention has been made to solve the above-mentioned problems of the prior art. It has a simple structure and abuts a sliding surface with a constant contact area and frictional force regardless of the pressure fluctuation of the sealed fluid. Another object of the present invention is to provide a sealing device which has stable operation characteristics, is durable with reduced wear of the lip end portion of the seal member, and has good sealing characteristics such as eccentricity tracking.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a gap is provided between a housing member and a shaft which are provided coaxially and which reciprocate relative to each other, and is fixed to one member. A sealing device including a rubber-like elastic seal member that seals a sealing fluid between the sliding surface of the other member and a holding member that is located on the anti-sealing fluid side of the sealing member and holds the sealing member. In the above, the seal member includes a fixed portion, a radial portion that extends in the radial direction from the fixed portion, and a lip portion that projects from the sliding surface side of the radial portion toward the sealed fluid side. The contact surface with the member has an annular convex strip, and the holding member is provided with an annular concave groove fitted on the convex strip on the contact surface with the seal member. The sealing member can be deformed to the holding member side under the pressure of the sealing fluid. Characterized in that it comprises a room area to be.

The sectional shape of the annular groove of the holding member is
It is also preferable to provide a side surface continuous from the edge on the sliding surface side of the contact surface with the seal member to the bottom of the concave groove in a stepwise manner.

It is also preferable that the holding member is a rod guide that supports a shaft.

[0016]

In the present invention configured as described above, when the pressure of the sealing fluid increases, the sealing fluid presses the sealing fluid side of the seal member, and the annular convex portion of the seal member and the vicinity thereof. The radial portion is projected into the space area in the annular groove of the holding member to shorten the shape of the lip portion and enhance the rigidity. The lip portion with increased rigidity acts so as to make the tightening force constant against the pressure of the sealing fluid, and suppresses the change in the contact area with the sliding surface to make the sliding resistance constant.

By making the cross-sectional shape of the concave groove a stepwise wall surface continuous to the bottom of the concave groove, the ridge portion of the sealing member projects to a position corresponding to the pressure of the sealing fluid, and within a predetermined pressure range. Stay in that position.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

FIGS. 1 and 2A and 2B show an embodiment to which the present invention is applied. FIG. 1 is a cross-sectional explanatory view of a sealing device 1 which is provided coaxially and mainly includes an annular seal member 5 and a holding member 4 that seal a gap between a housing member 2 and a shaft 3 that perform relative reciprocal movement, The seal member 5 is shown in a shape in which it is not restricted by the housing member 2 and the shaft 3. Further, the holding member 4 is located on the opposite side of the seal member 5 in contact with the sealing fluid L1, and the contact surface 4a with the seal member 5 and the contact surface 5d with the holding member 4 of the seal member 5 are in contact with each other. ing.

The seal member 5 is fixed to the inner periphery of the housing member 2, and includes a fixed portion 5a, a radial portion 5b extending radially inward from the fixed portion 5a, and sliding of the shaft 3 of the radial portion 5b. Lip portion 5 protruding from the surface side to the sealed fluid L1 side
c. In the present embodiment, the lip portion 5c has a length of l _A , and in a free-form state in which it does not contact the sliding surface of the shaft 3, a predetermined tightening force is applied when it contacts the shaft 3. Open outward so that it abuts. In this embodiment, FIG. 1 shows that the pressure of the sealed fluid L1 is low (10 to 20 k).
g / cm ² ) and when the sealing device 1 is actually operating at a low pressure, it contacts the sliding surface of the shaft 3 for a length of l _A1 from the lip tip 5e. .
Reference numeral 5f is an annular convex strip protruding from the contact surface 5d, and is fitted into an annular concave groove 4f of the holding member 4 described later.

The holding member 4 has a contact surface 4a with which the seal member 5 is abutted.
And an annular groove 4f. The cross-sectional shape of the annular groove 4f is such that the inclination and depth of the wall surfaces 4d and 4f are determined to be a desired shape depending on the conditions under which the sealing device 1 is used and the hardness and elastic deformation characteristics of the seal member 5. However, in the present embodiment, the wall surface 4d on the sliding surface side of the shaft 3 is formed stepwise, and the step portion 4b is formed between the bottom portion 4c and the contact surface 4a. Contact surface 4a of step 4b
Depth from is l _1, the depth from the contact surface 4a of the bottom portion 4c has a 1 _1.

Further, the annular groove 4f of the holding member 4 is provided with a room area 6 in a state where the pressure of the sealing fluid is low and the sealing member 5 is fitted without deformation.

Next, the operation of the sealing device 1 of the present embodiment configured as described above will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, the pressure of the sealing fluid L1 used in the sealing device 1 is low (0 to 20 kg / cm ² ).
2A, the pressure of the sealing fluid L2 is medium pressure (20 to 50 kg / cm ² ), and FIG. 2B is the high pressure of the sealing fluid L3 (50 to 100 kg / cm ^2). ) Shows the state of.

When the pressure of the sealing fluid L1 is low, the annular projection 5f of the seal member 5 is not deformed, and the lip portion 5c of the seal member 5 has a length of l _A1 with the sliding surface of the shaft 3. Only in contact. In this state of FIG. 1, when the pressure of the sealed fluid L1 increases (up to about 20 kg / cm ² ), the lip portion 5
When c is subjected to the pressure associated therewith, the tightening force with the sliding surface of the shaft 3 increases, and at the same time the contact length l _A1 with which it abuts increases.

However, when the pressure of the sealing fluid L1 rises to a predetermined pressure region (15 to 25 kg / cm ² in this embodiment), the annular convex strip of the seal member 5 as shown in FIG. 2 (a). 5f and the radial portion 5b in the vicinity thereof are the sealing fluid L.
It will bend to the pressure of 2 and will protrude to the room area 6 in the annular groove 4f of the holding member 4.

[0027] In this state, the sealing member 5 is elastically deformed by protruding annular ridge 5f to the step portion 4b in 1 ₁ of depth from the contact surface 4a, due to the elastic deformation The length of the lip portion 5c is reduced from 1 _A to 1 _B , and the rigidity is increased. Therefore, the length of the lip portion 5c is shortened and the rigidity thereof is increased to reduce the increase of the tension force against the pressure of the sealing fluid L2, and the contact length l _B1 with the sliding surface of the shaft 3 is sealed. The length is almost the same as the contact length l _A1 of the lip portion 5c in the state where there is no influence of the pressure of the fluid L1, and the change in the contact area is suppressed, and as a result, the increase in sliding resistance is prevented.

In the state shown in FIG. 2A, when the pressure of the sealing fluid L2 is maintained in the medium pressure range and the pressure of the sealing fluid L2 becomes higher (40 to 60 kg / cm in this embodiment).
² ) The state shown in FIG.

The bottom 4 this state that the seal member 5 is in the 1 ₂ deep annular ridge 5f is elastically deformed from the contact surface 4a
Since it is projected up to c, the length of the lip portion 5c is further reduced from 1 _B to 1 _{C due} to this elastic deformation, and the room area 6 is almost eliminated. Even in this state, the contact length l _C1 of the sliding surface with the shaft 3 is the contact length l _C of the lip portion 5c in a state where the pressure of the sealing fluid L1 does not influence.
_{In the} medium pressure region, _A1 and the sealing fluid L2 have the same length as the contact length l _B1 , which similarly suppresses a change in the contact area and, as a result, prevents an increase in sliding resistance.

FIG. 3 is a diagram showing a change in the sliding resistance of the sealing device 1 according to a change in the pressure region of the sealing fluid in the above-described embodiment, and the line G2 of the conventional example shows the sealing fluid. While the sliding resistance increases in proportion to the increase in the pressure of, the seal member 5 in the present embodiment changes in three stages in accordance with the pressure as described above. The absolute value of dynamic resistance is low, and the range of change in sliding resistance R1
Is smaller than the conventional example.

In this embodiment, the seal member 5 has a bifurcated shape, but the fixed portion 5a does not have to extend to the sealed fluid side, and the wall surface 4d on the sliding surface side of the shaft 3 of the holding member 4 is also acceptable.
It is also possible to form a smooth inclined surface instead of the step shape, and in that case, the sliding resistance changes as shown in FIG. In the line diagram G2 of the conventional example, the sliding resistance increases in proportion to the increase in the pressure of the sealed fluid, whereas in this case, the increase of the sliding resistance remains within the range of R2. Further, in this embodiment, the pressure of the sealed fluid is set to be between 0 and 100 kg / cm ² , but it goes without saying that this also differs depending on the environment in which it is used.

[0032]

EFFECT OF THE INVENTION The present invention has the above-described structure and operation. Since the predetermined contact force and the contact area between the sliding surface and the sliding surface are maintained regardless of the pressure fluctuation of the sealed fluid, the pressure dependence of the sealing performance is reduced. It becomes smaller and the sealing property is improved. Further, even if the pressure of the sealing fluid increases, the frictional force with the sliding surface does not increase, the increase of sliding resistance is prevented, wear is suppressed, and durability is improved.

The holding member provided with a stepped step in the concave groove can control the sliding resistance in accordance with a predetermined pressure range.

Further, by using the holding member as a rod guide for supporting the shaft, it is possible to make the parts multifunctional, reduce costs, and add value.

[Brief description of drawings]

FIG. 1 is a diagram of a sealing device according to an embodiment of the present invention.

FIG. 2 is a diagram of a sealing device according to an embodiment of the present invention.

FIG. 3 is a diagram of sliding resistance of the sealing device according to the embodiment of the present invention.

FIG. 4 is a diagram of sliding resistance of the sealing device according to the embodiment of the present invention.

FIG. 5 is a conventional sealing device.

[Explanation of symbols]

 1 Sealing Device 2 Housing Member 3 Shaft 4 Holding Member 4a Abutment Surface 4b Step 4c Bottom 4d Wall 4e Wall 4f Groove 5 Sealing Member 5a Fixing 5b Radial 5c Lip 5d Abutment 5e Lip Tip 5f Convex 6 room area L1, L2, L3 Sealed fluid

Claims (3)

[Claims] 1. A rubber which is provided coaxially and seals a gap between a housing member which relatively reciprocates and a shaft, and which is fixed to one member and seals a sealing fluid between a sliding surface of the other member. In a sealing device provided with a sealing member of elastic body and a holding member for holding the sealing member located on the anti-sealing fluid side of the sealing member, the sealing member includes a fixing portion and a radial direction from the fixing portion. An extending radial portion and a lip portion projecting from the sliding surface side of the radial portion toward the sealed fluid side, and further having an annular projection on the contact surface of the radial portion with the holding member, The holding member is provided with an annular concave groove on the contact surface with the sealing member that fits into the convex strip, and the annular concave groove is deformable toward the holding member side when the sealing member receives the pressure of the sealing fluid. A sealing device having a room area to be provided. 2. The cross-sectional shape of the annular recessed groove of the holding member has a side surface that is continuous from the edge on the sliding surface side of the contact surface with the seal member to the bottom of the recessed groove. The sealing device according to claim 1, which is characterized in that: 3. The sealing device according to claim 1, wherein the holding member is a rod guide that supports a shaft.