JP2006112486A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide technique capable of restraining variation of friction and capable of maintaining stable sealing performance even when a pressure of a target fluid to be sealed is varied. <P>SOLUTION: In a slipper seal 1 equipped with a seal ring 2 and a back ring 3 provided on a groove bottom 15a side of an annular groove 14 more than the seal ring 2 and having a squeeze margin so as to seal an annular space 13, a side ring 4 arranged on the pressure side of the seal ring 2 and in a side ring attachment groove 16 provided on a side wall 15b of the annular groove 14 and having a groove bottom 16a shallower than a groove bottom 15a is provided, and the side ring 4 is closely fitted to the groove bottom 16a and the seal ring 2 by the pressure acting from the pressure side, and seals the annular space 13 between the groove bottom 16a and the seal ring 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sealing device for sealing an annular gap between two members provided to be relatively movable.

  As a sealing device of this type, for example, a piston portion and a rod portion seal of a hydraulic / pneumatic cylinder are required to have low friction. Therefore, a seal (so-called slipper seal) excellent in low friction and wear resistance is applied by selecting a resin material for the sliding surface.

  FIG. 12 is a cross-sectional configuration explanatory view showing a slipper seal 100 as an example of a conventional sealing device. In addition, in FIG. 12, the state at the time of no pressure is shown.

As shown in FIG. 12, the slipper seal 100 is mounted in a mounting groove 110a provided in the shaft 110, and seals the annular gap between the shaft 110 and the cylinder housing 120. A seal ring 101 that slides on the housing 120 and a back ring 102 that is formed of an elastic body such as rubber or urethane and is provided on the inner peripheral side of the seal ring 101 are provided. The back ring 102 is provided with a crushing allowance E to apply a tightening force (force generated when the seal ring 101 contacts the cylinder housing 120) to the seal ring 101.
As a document disclosing related conventional examples, there is Patent Document 1.
Japanese Utility Model Publication No. 62-133005

  By the way, the slipper seal 100 as described above obtains an urging force by giving a crushing margin of the buckling 102 when there is no pressure, but at the time of pressurization (when the pressure of the fluid to be sealed increases) There is a concern that the friction changes according to the pressure and becomes larger than when no pressure is applied.

  This point will be further described with reference to FIG. FIG. 13 is a diagram showing a state during pressurization in which the pressure P is applied in FIG.

  When the pressure P is applied from the pressure side, the pressure P is pressed to the counter pressure side (the side opposite to the pressure side on which the pressure P acts), whereby an expansion force is applied to the buckling 102 (the buckling 102 is a seal ring). 101 or force generated when contacting the groove bottom of the mounting groove 110a. When this expansion force is applied to the seal ring 101, the force with which the seal ring 101 is applied to the cylinder housing 120 is increased, and the friction is increased.

Here, assuming that the rod diameter is d, the seal ring height is b, the pressure is P, and the seal pressing force at no pressure is Pr0, the pressing force Pr1 when the pressure is applied is
Pr1 = π · d · b · P + Pr0
It can be expressed as

The present invention has been made in view of the circumstances as described above, and provides a technique capable of maintaining stable sealing performance by suppressing changes in friction even when the pressure of a fluid to be sealed changes. For the purpose.

In order to achieve the above object, the present invention provides:
A sliding ring that is attached to an annular groove formed on one of the two members that are assembled so as to be relatively movable and slides on the other member of the two members, and the annular groove is formed by the sliding ring. A biasing ring provided on the groove bottom side and provided with a crushing margin with respect to the length between the sliding ring and the groove bottom, and sealing the annular gap between the two members In the device
A side ring disposed on a pressure side of the sliding ring and disposed on a pressure side wall of the annular groove and having a groove bottom shallower than a groove bottom of the annular groove;
The side ring is characterized in that an annular gap between the groove bottom and the sliding ring is sealed in close contact with the groove bottom of the stepped portion and the sliding ring by pressure acting from the pressure side.

  With this configuration, during pressurization, the pressure acting from the pressure side is sealed by the side ring, so that the pressure acts on the urging ring provided on the counter pressure side of the side ring. This can be suppressed. Therefore, it is possible to suppress an increase in the tension force on the other member, and it is possible to suppress an increase in friction during pressurization.

In the above configuration, the stepped portion is provided on both side walls of the annular groove,
The side rings may be provided respectively on the step portions provided on the both side walls.

  Thereby, the sealing device according to the present invention is not only applied as a so-called one-sided (one-pressure) seal in which pressure acts from one side of the sealing device, but also from which pressure acts from both sides of the sealing device, It can also be suitably applied as a so-called both-side (both pressure) seal.

  In the above-described configuration, the groove is formed on the pressure side of the peripheral contact surface of the side ring, which is closer to the pressure contact portion than the sealing contact portion in close contact with the stepped portion and closer to the sliding contact portion. It is also preferable to comprise.

  By configuring in this way, the pressure in the space between the side ring and the biasing ring becomes higher than the pressure on the pressure side of the side ring, and the close state between the side ring and the groove bottom of the stepped portion is maintained. When released, the space and the annular gap side communicate with each other through the groove. Thereby, even when there is a possibility that accumulated pressure is generated in the space, the accumulated pressure can be released, so that it is possible to suppress an adverse effect caused by the accumulated pressure.

  In the above configuration, the opposing surface of the sliding ring that faces the other member is recessed at the center and both ends project toward the other member to form a sliding portion with the other member. It is also preferable that the cross-sectional shape is substantially concave.

  By comprising in this way, in a sliding ring, the area which carries out sliding contact with the other member can be made smaller. Therefore, at the time of pressurization, it is possible to suppress the occurrence of leakage due to the fluid to be sealed blown out from the sliding surface between the sliding ring and the other member.

  In addition, said each structure can be employ | adopted combining as much as possible.

ADVANTAGE OF THE INVENTION According to this invention, even when the pressure of the fluid for sealing changes, it becomes possible to provide the technique which can suppress the change of friction and can maintain the stable sealing performance.

  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, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments. In the drawings shown below, hatching may not be given for convenience even when a cross section is shown.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing a state in which a slipper seal 1 as a sealing device according to Embodiment 1 of the present invention is provided in an annular gap 13 between two members, and FIG. The state (b) of FIG. 2 shows a state during pressurization. FIG. 2 is a schematic cross-sectional view showing the slipper seal 1 according to the present embodiment. FIG. 3 is a schematic cross-sectional view for explaining the annular groove 14 in which the slipper seal 1 according to the present embodiment is mounted.

  The slipper seal 1 according to the present embodiment is suitably applied to, for example, various hydraulic cylinders driven by high-pressure hydraulic oil (sealing target fluid) and piston portions and rod portions of pneumatic cylinders. (Shaft member) 11 is mounted in an annular groove 14 provided on the outer peripheral surface of the rod 11, and the outer peripheral surface of the rod 11 and the inner peripheral surface 12a of a cylinder housing or rod guide (here, referred to as the housing 12) through which the rod 11 is inserted. The annular gap 13 between the two is sealed.

  This prevents leakage of the fluid to be sealed (hydraulic fluid, air, etc.) existing on the pressure side (sealed fluid side), and maintains an appropriate amount of oil film on the inner peripheral surface 12a of the housing 12 to improve the lubricity sliding performance. Etc.

  Here, the rod 11 constitutes one member of the two members, and the housing 12 constitutes the other member of the two members. Further, the rod 11 and the housing 12 are provided coaxially and relatively freely movable, and may be relatively rotated or relatively reciprocated.

  Below, the slipper seal 1 which concerns on this Embodiment is demonstrated.

  The slipper seal 1 includes a seal ring 2 as a sliding ring that slides on the inner peripheral surface 12 a of the housing 12, and a biasing ring that biases the seal ring 2 toward the housing 12 and applies a pressing force to the seal ring 2. And a side ring 4 provided on both ends of the seal ring 2 in the axial direction.

  The seal ring 2 has a substantially rectangular cross-sectional shape, and is made of a resin member for the purpose of wear resistance and a low friction coefficient (reduction of sliding heat generation). The seal ring 2 is preferably made of, for example, PTFE (tetrafluoroethylene resin) or PA (polyamide resin).

  The back ring 3 is composed of a rubber-like elastic body in order to apply a pressing force Pr0 to the seal ring 2. The buckling 3 is preferably composed of, for example, NBR (nitrile rubber), UR (polyurethane), or the like.

The side ring 4 is constituted by an O-ring having a wire diameter smaller than the radial thickness of the seal ring 2. Side ring 4 is the same as back ring 3, NBR (nitrile rubber), U
It may be composed of R (polyurethane) or the like.

  The annular groove 14 to which the slipper seal 1 is attached is provided with a main groove 15 for mainly attaching the seal ring 2 and the back ring 3 and side walls 15b on both sides of the main groove 15, respectively. A side ring mounting groove 16 is provided for mounting. Here, the side ring attachment groove 16 constitutes a step portion according to the present invention.

  Next, the relationship between the slipper seal 1 and the annular groove 14 will be described.

  The cross-sectional shape of the seal ring 2 is smaller than the cross-sectional shape of the main groove 15. That is, the seal ring 2 is such that H1 <W1 when the height (axial length) of the seal ring 2 is H1 and the groove width (axial length) of the main groove 15 is W1. Is provided. The thickness of the seal ring 2, that is, the radial width (thickness) of the seal ring 2 is T1, and the groove depth, that is, the groove bottom of the main groove 15 (annular groove 14), When the length (in the axial direction) to the peripheral surface 12a is h, T1 <h is provided.

  The slipper seal 1 in which the back ring 3 and the side ring 4 are combined with such a seal ring 2 is provided so as to have a crushing margin in both the axial direction and the radial direction with respect to the annular groove 14. .

  That is, the slipper seal 1 is crushed so that T2> h, where T2 is the thickness of the slipper seal 1, that is, the radial length when the seal ring 2 and the back ring 3 are combined. Is provided.

  Further, the height of the slipper seal 1, that is, the length in the axial direction when the seal ring 2 and two side rings 4 provided so as to sandwich the seal ring 2 are combined is H2, and the side ring mounting groove 16 Groove width, that is, from the end surface 16b provided at the end portion in the axial direction of the side ring mounting groove 16 provided on one side wall 15b (this end surface has a radially extending surface) 16b, The length to the end surface 16b of the side ring attachment groove 16 provided in the side wall 15b is set to W2. In this case, the slipper seal 1 is provided with a crushing margin so that H2> W2.

  Here, in the present embodiment, since the seal ring 2 is made of a resin member, the slipper seal 1 is provided with a crushing margin. It can also be said that the side ring 4 is provided with a crushing margin in the direction.

  In the slipper seal 1 configured as described above, when no pressure is applied, as shown in FIG. 1A, the back ring 3 is provided with a crushing margin so that the seal ring 2 comes into sliding contact. A pressing force Pr0 is generated on the inner peripheral surface 12a of the housing 12 and the groove bottom 15a of the main groove 15 with which the back ring 3 contacts.

  Furthermore, by providing the side ring 4 with a crushing margin, a pressing force is generated on the end surface of the seal ring 2 that the side ring 4 contacts and the end surface 16b of the side ring mounting groove 16 that the side ring 4 contacts. To do.

  Thereby, the annular gap 13 is sealed.

At the time of pressurization, as shown in FIG. 1 (b), the buckling 3 is provided with a crushing margin, whereby the inner peripheral surface 12a of the housing 12 on which the seal ring 2 slides,
In addition, a pressing force is generated at the groove bottom 15a of the main groove 15 with which the back ring 3 contacts.

  Further, the side ring 4 is provided with a crushing allowance, and due to the expansion force of the side ring 4 generated by the action of the pressure P, the end surface of the seal ring 2 that the side ring 4 contacts and the side ring 4 Tightening force is generated on the end surface 16b of the side ring mounting groove 16 that comes into contact. Further, due to the action of the pressure P, the side ring 4 has an end surface provided on the axial center side (side farther away from the housing 12) in the radial direction in the side ring mounting groove 16 (this end surface is in the axial direction). (Which has a surface extending in the direction). Here, the end face 16a constitutes the groove bottom of the step portion according to the present invention.

  Thereby, the annular gap 13 is sealed.

  At this time, the A chamber partitioned by the sliding surface between the seal ring 2 and the inner peripheral surface 12a of the housing 12, and the end surface 16b of the seal ring 2, the side ring 4, and the side ring mounting groove 16 (FIG. 1B). ), The sealing function can be exerted in the space B), which is on the counter-pressure side from the chamber A, and is enclosed in the chamber B provided with the buckling 3 (B in FIG. 1B). Hydraulic pressure is not introduced into the space), and it is possible to suppress the pressure from acting on the buckling 3.

  Thereby, it is possible to suppress an increase (change) in the tightening force with respect to the inner peripheral surface 12a of the housing 12 on which the seal ring 2 slides. Therefore, it is possible to suppress an increase in friction at a high pressure.

  Here, the B chamber is a chamber partitioned by the contact surface between the back ring 3 and the groove bottom 15a of the main groove 15, and the end surface 16b of the seal ring 2, the side ring 4, and the side ring mounting groove 16. Is.

(Embodiment 2)
In the first embodiment described above, there is a possibility that the accumulated pressure in the B room shown in FIG. In the second embodiment, as a countermeasure in such a case, a groove (slit) 4A1 for avoiding pressure accumulation is provided on the side ring 4A.

  FIG. 4 is a schematic cross-sectional view showing a state in which a slipper seal 1A as a sealing device according to the present embodiment is provided in an annular gap 13 between two members. FIG. 5 is a schematic diagram showing the side ring 4A in the present embodiment, and shows the side ring 4A of the portion C shown in FIG. FIG. 6 is an enlarged view of the A chamber shown in FIG. 4, in which FIG. 6 (a) shows a state during pressurization, and FIG. 6 (b) shows a state during pressure accumulation. In the present embodiment, the slipper seal 1 described in the first embodiment is provided with a slit in the side ring, and other configurations are the same as those in the first embodiment. The same reference numerals are given and description thereof is omitted.

  The feature of this embodiment is that a slit 4A1 is provided on the A chamber side of the peripheral surface of the side ring 4A, as shown in FIGS. Here, the side A chamber side of the peripheral surface of the side ring 4A in which the slit 4A1 is provided is specifically attached to the side ring when combined as a slipper seal 1A as shown in FIG. 6 (a). Provided in a range that is on the pressure side of the sealing contact portion 4A2 of the side ring 4A that is in close contact with the end face 16a of the groove 16 and that is on the pressure side of the sealing contact portion 4A3 of the side ring 4A that is in close contact with the seal ring 2. Yes. Note that the shape and dimensions of the slits 4A1 may be set as appropriate, and the number of slits 4A1 may be set as appropriate. However, the slits 4A1 may be provided at equal intervals (equally spaced) in the circumferential direction. .

By constituting in this way, at the time of pressurization, by the action of pressure from the pressure side,
When the side ring 4A is pressed against the end surface 16a of the side ring attachment groove 16, the sealing contact portions 4A2 and 4A3 become seal portions. Therefore, the hydraulic pressure is not introduced into the B chamber, and it is possible to suppress the pressure from acting on the buckling 3. As a result, it is possible to suppress an increase (change) in the pressing force on the inner peripheral surface 12a of the housing 12 on which the seal ring 2 slides, and to suppress an increase in friction at high pressure. it can.

  When the pressure accumulation D is generated in the B chamber, the side ring 4A is separated from the end surface 16a of the side ring mounting groove 16 by the pressure from the B chamber side, and the housing in the radial direction in the side ring mounting groove 16 is provided. It comes to be pressed against the end surface 16c provided on the 12 side (this end surface has a surface extending in the axial direction).

  As a result, the contact state between the side ring 4A and the end surface 16a of the side ring mounting groove 16 is released, and the A chamber and the B chamber can be communicated through the slit 4A1 of the side ring 4A. Accumulated pressure D flows to the annular gap 13 side.

  As described above, when the accumulated pressure is generated in the B chamber, the accumulated pressure can be released, so that it is possible to suppress the adverse effect caused by the accumulated pressure in the B chamber. In other words, it is possible to suppress adverse effects on the sealing performance of the slipper seal 1A and reduce the durability of the slipper seal 1A.

(Embodiment 3)
In the first embodiment described above, when the pressure acting from the pressure side is higher (for example, when applied as a sealing device for high-pressure applications), the seal ring 2 and the inner peripheral surface 12a of the housing 12 There is a possibility that the fluid to be sealed blows out from the sliding surface and leakage occurs. In the third embodiment, as a countermeasure for such a case, the cross-sectional shape of the seal ring is made substantially concave, and the seal ring portion (contact area) that is in sliding contact with the inner peripheral surface 12a of the housing 12 is reduced. is there.

  FIG. 7A is a schematic sectional view showing a state in which a slipper seal 1B as a sealing device according to the present embodiment is provided in an annular gap 13 between two members, and FIG. 7B is an embodiment shown in FIG. It is a schematic sectional drawing showing the slipper seal 1 of the form 1 of. In the present embodiment, the cross-sectional shape of the seal ring is different from that of the slipper seal 1 described in the first embodiment, and other configurations are the same as those in the first embodiment. The same reference numerals are given and description thereof is omitted.

  As a feature of the present embodiment, in the seal ring 2A as a sliding ring, the opposing surface facing the housing 12 has a central portion 2A1 that is depressed, and both end portions 2A2 project toward the housing 12 and come into contact with the housing 12. It is provided in a concave cross-sectional shape that constitutes a sliding portion with the housing 12.

  Thus, by making the area of the sliding portion that slides with the housing 12 smaller than that in the case of the seal ring 2 in the first embodiment described above, the peak of the compressive force generated on the inner peripheral surface 12a of the housing 12 is achieved. The magnitude of the value P1max can be made larger than when the seal ring 2 is used (P2max shown in FIG. 7B).

Thereby, when the seal ring 2 according to the first embodiment is used, even when the tension force P2max generated on the inner peripheral surface 12a of the housing 12 may be smaller than the pressure P acting from the pressure side, By using the seal ring 2 </ b> A of the present embodiment, the magnitude of the peak value P <b> 1 max of the tension generated on the inner peripheral surface 12 a of the housing 12 can be made larger than the pressure P.

  Therefore, it is possible to suppress the occurrence of leakage due to the sealing target fluid blowing through the sliding surface between the seal ring 2A and the inner peripheral surface 12a of the housing 12 during pressurization.

  In the seal ring 2A, the shape of the ring body, such as the size of the area where both end portions 2A2 contact the inner peripheral surface 12a of the housing 12, and the crushing cost of the back ring 3 are generated on the inner peripheral surface 12a of the housing 12. It is preferable that the peak value P1max of the tightening force is appropriately set so as to be larger than the pressure P. In the present embodiment, the shape of the seal ring 2A is substantially concave in cross section. However, the present invention is not limited to this, and the sliding area with the inner peripheral surface 12a of the housing 12 is smaller than that of the seal ring 2. Any shape may be used as long as the peak value of the pressing force generated on the inner peripheral surface 12a of the housing 12 becomes larger than the pressure P by setting the crushing allowance of the buckling 3.

(Other embodiments)
FIGS. 8-11 is a schematic sectional drawing which shows the state by which the slipper seal as a sealing device which concerns on other embodiment was provided in the annular clearance 13 between two members. In addition, the same code | symbol is attached | subjected about the component similar to embodiment mentioned above, and the description is abbreviate | omitted.

  In the embodiment described above, the back ring and the side ring as the urging ring have been described as the O-ring. However, the present invention is not limited to this, and the rectangular ring (back ring 3A, side ring 4B; FIGS. Or a D-ring having a substantially D-shaped cross section (back ring 3B, side ring 4D; see FIG. 10). Alternatively, an X ring (not shown) having a substantially X-shaped cross section may be used. By applying such a ring, the behavior of the ring body is stabilized, so that the sealing performance of the slipper seal can be improved. Any back ring may be used as long as the seal ring 2 is urged toward the housing 12 to generate a pressing force on the inner peripheral surface 12a of the housing 12, and the side ring is pressed against the seal ring 2. Any force generating force may be used (if a pressing force is generated on the seal ring 2, it is pressed against the end surface 16a of the side ring mounting groove 16 by the action of pressure during pressurization to exhibit a sealing function).

  Also, in the sealing device according to another embodiment, as described in the second embodiment, it is preferable to provide a slit for avoiding pressure accumulation in the side ring. FIG. 9A shows a state in which the accumulated pressure D is released through the slit 4C1 provided in the side ring 4C in the slipper seal using the square ring as shown in FIG. 8, and FIG. A side ring 4C provided with 4C1 is shown.

  Further, in the slipper seal shown in FIGS. 8 to 10, it is preferable to apply the seal ring 2A described in the third embodiment.

  Further, in the above description, the side ring is shown in the case where it is provided on both sides of the seal ring, so that it can be suitably applied to a so-called double side (both pressure) seal in which pressure acts from both sides of the slipper seal. Although it was a thing, it is not restricted to this. That is, in the case of a so-called one-side (one-pressure) seal in which pressure acts only from one side, the side ring 4 is provided only on one side of the seal ring 2 as shown in FIG. Also good. The shape of the side ring attachment groove 16 in this case is the groove shape provided on the side wall 15b of the main groove 15 as described above (it can also be said to have three surfaces and surround the side ring 4 from three sides). However, as shown in FIG. 11, it is only necessary to provide an end face 16a against which the side ring 4 is pressed by the action of pressure during pressurization.

  In the above description, the slipper seal as the sealing device is mounted on the annular groove 14 formed on the rod 11 as one of the two members. It may be mounted and slide on the outer peripheral surface of the rod (shaft member).

It is a schematic sectional drawing which shows the state by which the sealing device which concerns on Embodiment 1 of this invention was provided in the annular clearance between two members, The figure (a) shows the state at the time of no pressure, The figure (b) Indicates a state during pressurization. It is a schematic sectional drawing which shows the sealing device which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the annular groove where the sealing device which concerns on Embodiment 1 of this invention is mounted | worn. It is a schematic sectional drawing which shows the state by which the sealing device which concerns on Embodiment 2 of this invention was provided in the annular clearance between two members. It is the schematic which shows the side ring in Embodiment 2 of this invention. It is an enlarged view of the A room shown in FIG. 7A is a schematic cross-sectional view showing a state in which the sealing device according to Embodiment 3 is provided in an annular gap between two members, and FIG. 7B is a schematic cross-sectional view showing the sealing device shown in FIG. It is. It is a schematic sectional drawing which shows the state by which the sealing device which concerns on other embodiment was provided in the annular clearance between two members. It is a schematic sectional drawing which shows the state by which the sealing device which concerns on other embodiment was provided in the annular clearance between two members. It is a schematic sectional drawing which shows the state by which the sealing device which concerns on other embodiment was provided in the annular clearance between two members. It is a schematic sectional drawing which shows the state by which the sealing device which concerns on other embodiment was provided in the annular clearance between two members. It is a schematic sectional drawing which shows the conventional sealing device. It is a schematic sectional drawing which shows the conventional sealing device.

Explanation of symbols

1, 1A, 1B Slipper seal 2, 2A Seal ring 2A1 Central part 2A2 Both ends 3, 3A, 3B Back ring 4, 4A, 4B, 4C, 4D Side ring 4A1, 4C1 Slit 4A2, 4A3 Sealing contact part 11 Rod 12 Housing 12a Inner peripheral surface 13 Annular gap 14 Annular groove 15 Main groove 15a Groove bottom 15b Side wall 16 Side ring mounting groove 16a End face 16b provided on the axial center side in the radial direction 16b End face 16c provided on the axial end End face provided on the housing 12 side

Claims (4)

A sliding ring that is attached to an annular groove formed on one of the two members that are assembled so as to be relatively movable and slides on the other member of the two members, and the annular groove is formed by the sliding ring. A biasing ring provided on the groove bottom side and provided with a crushing margin with respect to the length between the sliding ring and the groove bottom, and sealing the annular gap between the two members In the device
A side ring disposed on a pressure side of the sliding ring and disposed on a pressure side wall of the annular groove and having a groove bottom shallower than a groove bottom of the annular groove;
The side ring is in close contact with the groove bottom of the stepped portion and the sliding ring by pressure acting from the pressure side, and seals the annular gap between the groove bottom and the sliding ring. apparatus. The step is provided on both side walls of the annular groove;
The sealing device according to claim 1, wherein the side rings are respectively provided in the step portions provided on the both side walls.   Of the peripheral surface of the side ring, a groove is provided on the pressure side of the sealing contact portion in close contact with the stepped portion and on the pressure side of the sealing contact portion in close contact with the sliding ring. The sealing device according to claim 1 or 2.   The opposed surface of the sliding ring that faces the other member has a substantially concave shape in cross section that has a recessed central portion and both end portions project toward the other member to form a sliding portion with the other member. The sealing device according to claim 1, wherein the sealing device is provided.

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