JP2010101426A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device capable of stabilizing the turbulence of surface pressure distribution when sealing as much as possible by stabilizing the behavior of a rubbery elastic body ring. <P>SOLUTION: The sealing device includes a resin seal ring 20, the rubbery elastic body ring 10 attached between an outer peripheral surface of the resin seal ring 20 and a groove bottom surface 53c in a circular groove 53. The outer peripheral surface of the resin seal ring 20 is composed of a low-pressure fluid side outer peripheral part 22 extending from a low-pressure fluid side end toward a high-pressure fluid side to an intermediate position on the outer peripheral surface, and a stepped part 21 with its diameter gradually increased outward in the radial direction from the high-pressure fluid side end of the low-pressure fluid side outer peripheral part 22 to regulate displacement of the rubbery elastic body ring 10 to the high-pressure fluid side. The rubbery elastic body ring 10 is composed to be held at a position slanting to the low-pressure fluid side in the circular groove 53. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealing device used for, for example, a rod seal of a fluid pressure cylinder, and more particularly to a combination type sealing device in which a rubber-like elastic ring and a resin seal ring are combined.

  As a conventional sealing device of this type, for example, a device as shown in FIG. 4 (A) is known.

  That is, this sealing device seals an annular gap between the shaft 101 and the housing 102 that reciprocally move relatively, and is a resin seal ring that is mounted in an annular groove 103 provided on the inner periphery of the housing 102. 120, and a rubber-like elastic ring 110 mounted in the annular groove 103 between the outer peripheral surface of the resin seal ring 120 and the groove bottom surface 103c.

  The resin seal ring 120 has an inner periphery that is slidably in contact with the shaft 101 in a sealed state, and seals the fluid to be sealed.

  The rubber-like elastic ring 110 is mounted in a radially compressed state between the outer peripheral surface of the resin seal ring 120 and the groove bottom surface 103c, and the elastic seal force causes the resin seal ring 120 to be attached to the shaft 101. The contact surface pressure is applied by pressing.

  A convex lip-shaped portion 130 is formed on the sliding surface of the resin seal ring 120 with the shaft 101 to improve the sealing performance by controlling the thickness of the oil film that enters and exits.

In this shape, since the outer peripheral surface of the resin seal ring 120 with which the rubber-like elastic ring 110 contacts is a flat shape parallel to the shaft 101, the annular groove 103 is affected by the pressure of the high-pressure fluid and the sliding resistance. The rubber-like elastic ring 110 swings left and right.
Then, the position of the tightening force acting from the rubber-like elastic ring moves in the axial direction, and the fact that the sliding surface is a convex lip-shaped portion 130 also affects the rubber-like elastic ring 110. The behavior of is not stable. Therefore, the surface pressure distribution on the sliding surface is also disturbed (see FIGS. 4B to 4D), the control of the thickness of the oil film becomes unstable, and leakage may occur.

In addition, as a sealing device of such a shape, it describes in patent document 1, for example.
JP 59-13166 A

  An object of the present invention is to provide a sealing device that can stabilize the behavior of a rubber-like elastic ring and stabilize the disturbance of the surface pressure distribution on the sliding surface as much as possible.

In order to solve the above problems, a sealing device of the present invention seals an annular gap between one member and the other member that reciprocate relative to each other, and is provided on the inner periphery of the other member. In a sealing device constituted by a resin seal ring mounted in an annular groove, and a rubber-like elastic ring mounted in the annular groove between the outer peripheral surface of the resin seal ring and the groove bottom surface,
The peripheral surface on the other member side of the resin seal ring has a low pressure fluid side outer peripheral portion extending from the low pressure fluid side end portion toward the middle position of the peripheral surface on the other member side toward the high pressure fluid side, and a low pressure fluid side outer periphery. And a step portion for restricting the movement of the rubber-like elastic ring toward the high-pressure fluid side from the end of the high-pressure fluid side in the radial direction, and the rubber-like elastic ring within the annular groove It is characterized in that it is held at a position biased toward the low-pressure fluid side.

  In this way, even when one member reciprocates, the rubber-like elastic ring is held in a predetermined position because the movement to the high-pressure fluid side is restricted by the step provided on the resin seal ring. The surface pressure distribution on the sliding surface of the resin seal ring can be stably maintained.

  If the circumferential surface on the one member side of the resin seal ring is provided with an annular recess that opens toward the high-pressure fluid side, and the sliding portion with the one member is provided at a position that is biased toward the low-pressure fluid side The pressing force of the rubber-like elastic ring held at a position biased toward the low-pressure fluid side acts stably on the sliding portion.

  Moreover, even if the sliding part is provided with a convex lip-shaped part toward one member side, the posture of the lip-shaped part can be stably held.

  In addition, since the rubber-like elastic ring has a structure that is supported at one place on the outer peripheral surface of the resin seal ring, the boundary between the stepped portion and the low-pressure fluid side outer peripheral portion, the high-pressure fluid of the rubber-like elastic ring The movement to the side can be restricted.

  If the rubber-like elastic ring has a structure that is supported at two locations on the outer peripheral surface of the resin seal ring, that is, the stepped portion and the low-pressure fluid side outer peripheral portion, the rubber-like elastic ring further moves to the high-pressure fluid side. Hard to do.

  According to the present invention, even when one member reciprocates, the rubber-like elastic ring is held at a predetermined position because the movement to the high-pressure fluid side is restricted by the step portion provided on the resin seal ring. The surface pressure distribution on the sliding surface of the resin seal ring can be stably maintained, and good sealing performance can be maintained.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

FIG. 3 shows a sealing device according to Embodiment 1 of the present invention.
<Configuration of sealing device>
The sealing device 200 seals an annular gap between a shaft 51 as one member that relatively reciprocates and a housing 52 as the other member, and is in an annular groove 53 provided on the inner periphery of the housing 52. And a rubber-like elastic ring 210 attached in the annular groove 53 between the outer peripheral surface of the resin seal ring 220 and the groove bottom surface 53c.

  The annular groove 53 is rectangular, the groove bottom surface 53c is parallel to the axial direction, and the groove side surfaces 53a and 53b are orthogonal surfaces orthogonal to the axial direction.

  The rubber-like elastic ring 210 is mounted in a state of being radially compressed between the outer peripheral surface of the resin seal ring 220 and the groove bottom surface 53c, and the resin seal ring 220 is attached to the shaft 51 by its elastic restoring force. The contact surface pressure is applied by pressing.

  The resin seal ring 220 has an inner circumference that is slidably in contact with the shaft 51 in a sealed state, and seals leakage of pressure fluid such as oil to the atmosphere as a fluid to be sealed. In this example, the high pressure fluid side H is described as the pressure fluid side, and the low pressure fluid side L is described as the atmospheric side.

  Preferable examples of the specific material of the resin seal ring 220 include PTFE and PA containing a filler.

  On the other hand, an annular recess 233 that opens toward the high-pressure fluid side H is provided on the inner peripheral surface of the resin seal ring 220, and the sliding surface 232 with the shaft 51 is provided at a position that is biased toward the low-pressure fluid side L. Yes.

  In the sealing device 201 according to the first embodiment, the outer peripheral surface of the resin seal ring 220 includes a low-pressure fluid-side outer peripheral portion 222 extending from the low-pressure fluid-side end toward the high-pressure fluid-side H to a midway position on the outer peripheral surface, and a low-pressure It has a stepped portion 221 that expands radially outward from the high-pressure fluid-side end of the fluid-side outer peripheral portion 222 and restricts the movement of the rubber-like elastic body ring 210 to the high-pressure fluid side H, and has a rubber-like elasticity. The body ring 210 is held in the annular groove 253 at a position biased toward the low pressure fluid side L.

  The step portion 221 of the resin seal ring 220 is provided with a gradient (tilt angle θ3) that is inclined in a direction in which the diameter gradually increases toward the fluid to be sealed in the axial direction. The inclination angle θ3 is such that the rubber-like elastic ring 10 having a circular cross section is geometrically located at one location near the boundary between the step portion 221 on the outer peripheral surface of the resin seal ring 220 and the outer peripheral portion 222 on the low-pressure fluid side (c3 in the figure). ) Is set to an inclination angle that can be supported by contact.

  In this example, the inclination angle θ3 is small, and it is not bent in two stages as in the first embodiment. The step portion 221 extends to the high pressure fluid side end as it is.

  On the other hand, an annular recess 233 that opens toward the high-pressure fluid side H is provided on the inner peripheral surface of the resin seal ring 220, and the sliding surface 232 with the shaft 51 is provided at a position that is biased toward the low-pressure fluid side L. Yes.

  The sliding surface 232 may be an inclined surface that slightly inclines so as to gradually decrease in diameter from the end of the low pressure fluid side L toward the axial high pressure fluid side, but in the illustrated example, a cylindrical surface parallel to the shaft 51 It has become.

  The annular recess 233 has a conical shape extending in parallel with the step 221 on the outer peripheral side.

  Further, unlike the first embodiment, the low pressure fluid side end surface 225 of the resin seal ring 220 is an orthogonal surface orthogonal to the central axis from the inner diameter end toward the outer diameter end. The high pressure fluid side end surface 227 of the resin seal ring 220 is also an orthogonal surface orthogonal to the central axis from the inner diameter end toward the outer diameter end.

<Excellent points of this embodiment>
In the first embodiment, a force that causes the rubber-like elastic body ring 210 to move relatively to the high-pressure fluid side H with respect to the resin seal ring 220 due to pressure fluctuation or reciprocation of the shaft 51 acts. Even so, the movement of the rubber-like elastic ring 210 is restricted by the step portion 221. Further, the movement of the rubber-like elastic ring 210 on the low-pressure fluid side L is restricted by the groove side surface 53 b of the annular groove 53.
Therefore, the pressing force by the rubber-like elastic ring 210 acts on substantially the same position of the resin seal ring 220, and an appropriate pressure distribution is maintained on the sliding surface 232 and the sealing performance is maintained.

Next, a second embodiment of the present invention will be described. In the following description, parts different from those of the first embodiment will be mainly described, and the same constituent parts will be denoted by the same reference numerals and the description thereof will be omitted.
FIG. 1 shows a sealing device according to Embodiment 2 of the present invention.

<Configuration of sealing device>
The sealing device according to the second embodiment also seals an annular gap between the shaft 51 as one member that relatively reciprocates and the housing 52 as the other member, and is provided on the inner periphery of the housing 52. A resin seal ring 20 mounted in the annular groove 53, a rubber-like elastic ring 10 mounted in the annular groove 53 between the outer peripheral surface of the resin seal ring 20 and the groove bottom surface 53c, It has.

  Also in Example 2, an annular recess 33 that opens toward the high-pressure fluid side H is provided on the inner peripheral surface of the resin seal ring 20, and the sliding surface 32 with the shaft 51 is biased toward the low-pressure fluid side L. In the position.

  The sliding surface 32 is an inclined surface that is slightly inclined so that the diameter gradually decreases from the end of the low pressure fluid side L toward the axial high pressure fluid side. The inclination angle α2 is set to about 8 °. The tip portion on the high-pressure fluid side H of the sliding surface 32 is a seal tip portion S that protrudes most toward the inner diameter side.

  In the second embodiment, the annular recess 33 is gradually extended from the end portion on the high pressure fluid side in parallel with the shaft 51 to the inner peripheral parallel portion 34 from the seal tip S to the inner peripheral parallel portion 34. An inner circumferential step portion 31 that is inclined greatly in the direction of increasing the diameter and is connected to the inner circumferential parallel portion 34 is provided.

  The outer peripheral surface of the resin seal ring 20 includes a low-pressure fluid-side outer peripheral portion 22 extending from the low-pressure fluid-side end toward the high-pressure fluid side H to a midway position on the outer peripheral surface, and the low-pressure fluid-side outer peripheral portion 22 on the high-pressure fluid side. A stepped portion 21 that expands radially outward from the end portion to restrict the movement of the rubber-like elastic ring 10 to the high pressure fluid side H, and an end portion on the high pressure fluid side H that is the maximum diameter of the stepped portion 21. The rubber-like elastic ring 10 is held in a position biased toward the low-pressure fluid side L in the annular groove 53 with a configuration having a high-pressure side outer peripheral portion 23 extending toward the axial high-pressure fluid side.

  The step portion 21 of the resin seal ring 20 is provided with a gradient (inclination angle θ1) that is inclined in the direction of gradually increasing the diameter toward the axial pressure fluid side.

The low pressure fluid side outer peripheral portion 22 is an inclined surface inclined by α _{1 with} respect to the axis.

  The inclination angle α1 of the low pressure fluid side outer peripheral portion 22 is the same as the inclination angle α2 of the inner peripheral sliding surface 32.

  In addition, the boundary portion of the step portion 21 on the outer peripheral side and the outer peripheral portion 22 on the low pressure fluid side that bends in a concave shape is formed at substantially the same position as the position of the seal tip portion S on the inner peripheral side when viewed in the axial direction.

In addition, the boundary between the step portion 21 on the outer peripheral side and the outer peripheral portion 23 on the high pressure side is the inner peripheral step portion 31 on the inner peripheral side.
And the boundary portion between the inner circumferential parallel portion 34 and the axial direction are almost the same position.

  The gradient is such that the rubber-like elastic ring 10 having a circular cross section is geometrically contacted at two locations (c1 and c2 in the figure) of the stepped portion 21 on the outer peripheral surface of the resin seal ring 20 and the outer peripheral portion 22 on the low-pressure fluid side. The tilt angle is set to such a degree that it can be supported. In particular, in the illustrated example, it is set to about 45 °.

  On the other hand, the low pressure fluid side end surface 25 of the resin seal ring 20 is an inclined surface that gradually inclines toward the high pressure fluid side H from the inner diameter end toward the outer diameter end. The inclination angle β1 of the low-pressure fluid side end face 25 with respect to the orthogonal plane orthogonal to the central axis N of the resin seal ring 20 is set to the same angle as the inclination angle α2 of the inner peripheral sliding face 32. . Therefore, the corner between the low-pressure fluid side end face 25 and the sliding face 32 is 90 °. Further, the corner portions of the sliding surface 32 and the low-pressure fluid side end surface 25 are rounded so as to suppress a sudden rise in surface pressure.

  The high pressure fluid side end surface 27 of the resin seal ring 20 is also an inclined surface that gradually inclines toward the high pressure fluid side H from the inner diameter end toward the outer diameter end. The inclination angle β2 of the high pressure fluid side end face 27 with respect to the orthogonal plane orthogonal to the central axis N of the resin seal ring 20 is also set to the same angle as the inclination angle β1 of the low pressure fluid side end face 25.

<Use condition of sealing device>
When the resin seal ring 20 and the rubber-like elastic ring 10 are combined and mounted in the annular groove 53 of the housing 52 and the shaft 51 is assembled, the inner peripheral sliding surface 32 is expanded and the rubber-like elastic ring. 20 is compressed in the radial direction between the outer peripheral surface of the resin seal ring and the groove bottom surface 53c of the annular groove 53, and the outer peripheral surface of the resin seal ring is pressed toward the inner diameter side by the elastic restoring force. Contacts the surface of the shaft 51.

  As shown in FIG. 1D, the surface pressure distribution P of the sliding surface has such a distribution that the seal surface pressure gradually decreases toward the low-pressure fluid side in the axial direction with the seal tip S as a peak. The high-pressure fluid side H rises rapidly, and the outflow amount and return amount of the high-pressure fluid are adjusted to appropriate amounts.

<Excellent points of this embodiment>
(I) Even if a force that causes the rubber-like elastic body ring 10 to move relatively to the high-pressure fluid side H with respect to the resin seal ring 20 due to pressure fluctuation or reciprocation of the shaft 51, the stepped portion 21 restricts the movement of the rubber-like elastic ring 10. Further, the movement of the rubber-like elastic ring 10 on the low pressure fluid side L is regulated by the groove side surface 53 b of the annular groove 53. Therefore, the pressing force by the rubber-like elastic ring 10 acts on substantially the same position of the resin seal ring 20, and an appropriate pressure distribution is maintained on the sliding surface 32, and the sealing performance is maintained.
ii) Furthermore, since the rubber-like elastic ring 10 is supported at two points, the rubber-like elastic ring 10 is difficult to roll.

FIG. 2 shows a modification of the second embodiment.
In this modification, the inclination angles of the sliding surface 32 ′, the low pressure fluid side outer peripheral portion 22 ′, the low pressure fluid side end surface 25 ′, and the high pressure fluid side end surface 27 ′ are set to zero. Other configurations are the same as those of the second embodiment, and the same components are denoted by the same reference numerals, and descriptions of the configurations and functions and effects are omitted.

  In addition, although Example 1, 2 demonstrated the rod seal which provided the annular groove in the housing, it is applicable not only to this but the piston seal which provided the annular groove in the axis | shaft.

FIG. 1 shows a sealing device according to Embodiment 2 of the present invention, in which FIG. (A) is an enlarged cross-sectional view of a main part in a mounted state, and (B) is an enlarged cross-sectional view of a main part in a state before mounting, FIG. 4C is a cross-sectional view of the resin seal ring, and FIG. 4D is a diagram showing the surface pressure distribution on the sliding surface. FIGS. 2A and 2B show a sealing device according to a modification of the second embodiment of the present invention. FIG. 2A is an enlarged cross-sectional view of the main part in the mounted state, and FIG. 2B is an enlarged main part in the state before the mounting. Sectional drawing and FIG. 4C are sectional views of a resin seal ring. 3A and 3B show the sealing device according to the first embodiment of the present invention, in which FIG. 3A is an enlarged cross-sectional view of a main part in a mounted state, and FIG. 3B is an enlarged cross-sectional view of a main part in a state before the mounting. is there. FIG. 4 shows a conventional sealing device. FIG. 4 (A) is an enlarged sectional view of a main part in the mounted state, and FIGS. 4 (B) to (D) are cases where the rubber-like elastic ring is swung in the axial direction. It is explanatory drawing which shows the state of the surface pressure distribution of a sliding surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rubber-like elastic ring 20 Resin seal ring 21 Step part 22 Low pressure fluid side outer peripheral part 23 High pressure side outer peripheral part 25 Low pressure fluid side end face 27 High pressure fluid side end face 31 Inner peripheral step part 32 Sliding surface 33 Annular recess 34 Inner circumference Parallel part 51 Shaft 52 Housing 53 Annular grooves 53a, 53b Groove side face 53c Groove bottom face 201 Sealing device 210 Rubber elastic ring 220 Resin seal ring 221 Stepped part 222 Low pressure fluid side outer peripheral part 225 Low pressure fluid side end face 227 High pressure fluid side end face 232 Sliding surface 233 Annular recess 253 Annular groove 101 Shaft 102 Housing 103 Annular groove 103c Groove bottom face 110 Rubber elastic ring 120 Resin seal ring 130 Lip-shaped part H High pressure fluid side L Low pressure fluid side N Center axis P Surface pressure distribution S Seal tip α1 Inclination angle (low pressure fluid side outer periphery 22)
α2 Inclination angle (sliding surface 32)
β1 angle of inclination (low pressure fluid side end face 25)
β2 Inclination angle (End surface 27 on the high pressure fluid side)
θ1 Inclination angle (step 21)
θ3 inclination angle (step 221)

Claims (5)

Seals an annular gap between one member and the other member that reciprocally move relative to each other, and includes a resin seal ring mounted in an annular groove provided on the inner periphery of the other member, and an annular groove In a sealing device composed of a rubber-like elastic ring attached between the outer peripheral surface of the resin seal ring and the groove bottom surface,
The peripheral surface on the other member side of the resin seal ring includes a low-pressure fluid-side outer peripheral portion extending from the low-pressure fluid-side end portion to a midway position on the other member-side peripheral surface, and the low-pressure fluid side And a step portion for restricting the movement of the rubber-like elastic ring toward the high-pressure fluid side from the end portion on the high-pressure fluid side of the outer peripheral portion in the radial direction. The sealing device is configured to be held at a position biased toward the low-pressure fluid side.   An annular recess that opens toward the high-pressure fluid side is provided on the peripheral surface of one side of the resin seal ring, and a sliding portion with the one member is provided at a position that is biased toward the low-pressure fluid side. The sealing device according to claim 1.   The sealing device according to claim 2, wherein the sliding portion is provided with a lip-shaped portion that protrudes toward one member side.   4. The rubber elastic ring according to claim 1, wherein the rubber-like elastic body ring is structured to be supported at one place on the outer peripheral surface of the resin seal ring, at a boundary portion between the stepped portion and the low pressure fluid side outer peripheral portion. The sealing device as described. The sealing device according to any one of claims 1 to 3, wherein the rubber-like elastic ring has a structure that is supported at two locations on the outer peripheral surface of the resin seal ring, the stepped portion and the outer peripheral portion on the low-pressure fluid side. .

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