JP2010190314A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device exhibiting excellent pressure resistance, although an attachment groove is a rectangular groove having a rectangular cross section, suppressing protrusion of a seal ring, and simplifying grooving work and reduction of a cost. <P>SOLUTION: The sealing device includes the seal ring, a relatively hard first backup ring arranged in a counter sealed fluid side thereof, and a relatively soft second backup ring arranged between the rings. The attachment groove is the rectangular groove having the rectangular cross section. The first backup ring has a tapered shape in a protruded portion provided on the seal ring side of a body part. The second backup ring has a tapered part corresponding to the tapered shape of the first backup ring and capable of overhanging on it. An initial gap is set between the body part of the first backup ring and the second backup ring. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealing device according to a sealing technique. The sealing device of the present invention is used for, for example, an injector for an in-cylinder direct injection gasoline engine or an in-cylinder high-pressure seal part.

  The applicant of the present application has previously proposed a sealing device 51 shown in FIG. 3, and this sealing device 51 is disposed between two members 61 and 62 facing each other to seal a sealing fluid, It is relatively hard on the anti-sealing fluid side of the seal ring 52 that is mounted in a mounting groove 63 provided in one member (for example, shaft) 61 of the two members 61 and 62 and is in close contact with the other member (for example, housing) 62. The first backup ring 53 is disposed, and a relatively soft second backup ring 54 is disposed between the rings 52, 53. When a high pressure is applied to the sealing device 51 from the sealed fluid side, the backup rings 53, 54 are disposed. However, by riding on the tapered shape 64 provided on the bottom surface of the mounting groove 63, it is possible to exhibit excellent pressure resistance and to suppress the protrusion of the seal ring 52 ( Patent reference 1).

  However, according to the above prior art, since it is necessary to provide the tapered shape 64 on the bottom surface of the mounting groove 63 as described above, the groove processing is performed as compared with the case where the mounting groove 63 is a rectangular groove having a rectangular cross section. It takes time and processing costs are high.

International Publication WO2006 / 070568

  In view of the above points, the present invention exhibits the same performance as the above prior art while the mounting groove is a rectangular groove having a rectangular cross section (exhibits excellent pressure resistance and can suppress the protrusion of the seal ring). Therefore, an object of the present invention is to provide a sealing device that can realize easy groove processing and cost reduction.

  In order to achieve the above object, a sealing device according to claim 1 of the present invention is a sealing device that is disposed between two members facing each other and seals a sealing fluid, and the sealing member is attached to one of the two members. A seal ring that is mounted in the provided mounting groove and is in close contact with the other member; a relatively hard first backup ring that is disposed on the anti-sealing fluid side of the seal ring; and between the seal ring and the first backup ring A relatively soft second backup ring disposed on the mounting groove, and the mounting groove is a rectangular groove having a rectangular cross section. The first backup ring includes an annular main body portion and a seal ring side of the main body portion. And a projecting portion provided in a portion near the bottom surface of the mounting groove, and in the direction in which the projecting portion approaches the bottom surface of the groove as it approaches the seal ring An inclined taper shape is provided, and the second backup ring is provided with a taper portion that can run on the taper shape corresponding to the taper shape of the first backup ring. An initial gap is set between the second backup ring and the second backup ring.

  A sealing device according to claim 2 of the present invention is a sealing device that is disposed between two members facing each other and seals a sealing fluid, and is provided in a mounting groove provided in one of the two members. A seal ring mounted and in close contact with the other member; a relatively hard first backup ring disposed on the anti-sealing fluid side of the seal ring; and a comparison disposed between the seal ring and the first backup ring A soft second backup ring, the mounting groove is a rectangular groove having a rectangular cross section, and the first backup ring is an annular main body portion and a surface of the main body portion on the seal ring side. A taper shape integrally including a projecting portion provided in a portion close to the other member, and inclining in the direction approaching the other member as the seal ring is approached to the projecting portion. The second backup ring is provided with a taper portion that can ride on the taper shape corresponding to the taper shape of the first backup ring, and the main body portion of the first backup ring and the second backup ring An initial gap is set between and.

  The sealing device according to claim 3 of the present invention is the sealing device according to claim 2, wherein the height dimension of the first backup ring is set to a dimension that does not cause crushing in an over-compressed state after eccentricity. The height dimension of the second backup ring is usually set in accordance with the height dimension of the mounting groove.

  In the sealing device of the present invention having the above-described configuration, the mounting groove is a rectangular groove having a rectangular cross section, and the tapered shape in the prior art is not provided at all. In the above prior art, the taper shape is set so that the groove height (depth) of the mounting groove gradually decreases (shallows) from the sealing fluid side to the anti-sealing fluid side, and the high pressure is applied to the sealing device from the sealing fluid side. As the backup ring rides on this taper shape when the pressure acts, the pressure resistance is exhibited and the protrusion of the seal ring is suppressed. On the other hand, in the present invention, the taper shape is provided not on the bottom surface of the mounting groove but on the first backup ring, and the second backup ring rides on the taper shape provided on the first backup ring. It is supposed to suppress the protrusion of the seal ring.

  For this reason, in the sealing device according to claim 1, the first backup ring includes an annular main body portion, and a projecting portion provided on a surface of the main body portion on the seal ring side and close to the groove bottom surface of the mounting groove. The projecting portion is provided with a taper shape that inclines in a direction approaching the groove bottom as it approaches the seal ring. The second backup ring is provided with a tapered portion that can ride on the tapered shape provided in the first backup ring. In addition, since the two backup rings must be displaced relative to each other when riding, an initial gap is set between the main body of the first backup ring and the second backup ring. Therefore, according to the above configuration, the second backup ring rides on the taper shape provided in the first backup ring, whereby the pressure resistance is exhibited and the protrusion of the seal ring is suppressed.

  In the sealing device according to claim 2, the first backup ring integrally includes an annular main body portion and an overhang portion provided on a portion close to the other member on the seal ring side surface of the main body portion. The latter projecting portion is provided with a tapered shape that inclines in a direction approaching the other member as it approaches the seal ring. The second backup ring is provided with a tapered portion that can ride on the tapered shape provided in the first backup ring. In addition, since the two backup rings must be displaced relative to each other when riding, an initial gap is set between the main body of the first backup ring and the second backup ring. Therefore, according to the above configuration, the second backup ring rides on the taper shape provided in the first backup ring, whereby the pressure resistance is exhibited and the protrusion of the seal ring is suppressed.

  Note that further consideration is required when the two members are eccentric (shaft eccentricity).

  That is, according to the sealing device of the first aspect, when one member and the other member are eccentric, the second backup ring is deformed due to the soft material on the overcompression side on the circumference, and the other member And fill the gap. On the non-compressed side on the circumference, the second backup ring rides on the tapered shape of the first backup ring and fills the gap with the other member.

  However, since the first backup ring is hard and difficult to deform, when the amount of eccentricity is large, there is a possibility that the first backup ring hits the other member strongly and breaks on the overcompression side. On the non-compression side, since a gap is generated between the first backup ring and the other member, there is a possibility that the second backup ring protrudes to the gap between the one member and the other member.

  On the other hand, in the sealing device according to the second aspect, as described in the third aspect, by setting the height dimension of the first backup ring to a dimension that does not cause crushing in the overcompressed state after eccentricity, The first backup ring is not crushed and broken even in the eccentric overcompressed state, and no gap is generated between the first backup ring and the other member on the non-compression side. Therefore, specifically, the diameter dimension of the surface facing the other member of the first backup ring is set to be approximately equal to the diameter dimension of the other member, and between the second backup ring and the groove bottom surface of the mounting groove. Set the initial gap to.

  Further, by setting the height dimension of the second backup ring in accordance with the height dimension of the mounting groove at normal time, the second backup ring is deformed at the time of eccentricity and fills the gap with the other member.

  The present invention has the following effects.

  That is, in the sealing device according to claim 1 or 2 of the present invention, the mounting groove is a rectangular groove having a rectangular cross section, and no tapered shape is provided in the groove. On the other hand, since the second backup ring rides over the taper shape provided in the first backup ring, pressure resistance is exhibited, and protrusion of the seal ring can be suppressed. Compared with the case where a taper shape is provided in the groove, it is much easier in terms of the process to provide the backup ring with a taper shape, and the processing cost can be reduced. Therefore, according to the intended purpose of the present invention, the mounting groove is a rectangular groove with a rectangular cross section, and can exhibit the same performance as the prior art (exhibiting excellent pressure resistance and suppressing the seal ring from protruding). Therefore, it is possible to provide a sealing device that can realize easy grooving and cost reduction.

  In addition to this, in the sealing device according to claim 3, the first backup ring is not crushed and broken even in the eccentric over-compressed state, and on the non-compression side, the first backup ring is interposed between the first backup ring and the other member. Since no gap is generated, the protrusion of the second backup ring can be effectively suppressed.

(A) is sectional drawing which shows the normal state of the sealing device which concerns on 1st Example of this invention, (B) is sectional drawing which shows the state at the time of eccentricity of the sealing device (A) is sectional drawing which shows the normal state of the sealing device which concerns on 2nd Example of this invention, (B) is sectional drawing which shows the state at the time of eccentricity of the sealing device Sectional drawing of the sealing device which concerns on a prior art example

  The present invention includes the following embodiments.

(1) The two-taper backup ring currently used for direct injection consists of a combination of hard and soft materials, and is effective against pressure resistance, O-ring protrusion and shaft eccentricity, and is a high-pressure seal. Widely used. However, it is necessary to provide a tapered portion in the groove shape. Therefore, the processing cost of a groove | channel becomes high compared with a rectangular groove | channel.

(2) Therefore, in the present invention, the shape of the backup ring (BR) of the hard material is changed to a shape in which the backup ring itself is tapered, and the same effect as the two-taper backup ring is obtained by the rectangular groove.

(3) Invention 1 has the following configuration.
(3-1) BR1 (hard material) is provided with a tapered portion on the rectangular + O-ring side (boots shape).
(3-2) BR2 (soft material) is tapered to match BR1.
(3-3) A clearance is provided between BR1 and BR2.

(4) Invention 2 has the following configuration.
(4-1) In contrast to Invention No. 1, the direction of BR is reversed in the axial direction.
(4-2) The BR1 height is set to a dimension that does not cause crushing even in an over-compressed state after eccentricity.
(4-3) The BR2 height is adjusted to the groove height in normal times (because BR2 can be deformed).

(5) In invention No. 1, the following effects are exhibited.
(5-1) The mounting groove becomes a rectangular groove, and the groove processing cost is reduced.
(5-2) At the time of eccentricity, BR2 is deformed due to the soft material on the overcompression side and fills the gap.
(5-3) On the non-overcompression side, BR2 climbs the taper portion of BR1 and fills the gap.

(6) However,
(6-1) Since BR1 is a hard material, it is difficult to deform, and if the eccentricity is large at the time of eccentricity, there is a possibility of cracking on the overcompression side.
(6-2) On the non-compression side, a clearance occurs between BR1 and the housing, and BR2 protrudes. The protrusion of BR2 protrudes to the groove clearance (between the shaft outer diameter and the housing), and the protrusion continues forever. Eventually, scratches may occur in the O-ring.

(7) According to Invention No. 2, the demerit described in (6) above is eliminated. That is,
(7-1) BR1 is not crushed or broken even in an eccentric over-compressed state.
(7-2) At the time of eccentricity, BR2 (soft material) is deformed to fill the gap.
(7-3) Clearance does not occur in BR1 and the housing on the non-overcompressed side. In addition, although a clearance is generated on the shaft side of BR1 and BR2 protrudes, it stops at a certain amount of protrusion (it does not protrude forever) because the protruding point is a dead end.

(8) Therefore, according to Invention No. 2, it is possible to suppress the protrusion of the O-ring due to eccentricity with a normal rectangular groove that does not use a tapered groove.

(9) BR1 is a hard material and uses nylon resin or the like. BR2 is a soft material such as PTFE resin.
(10) The O-ring is not particularly limited by the rubber material, but if it is for high pressure, a high hardness / high strength material is preferable. In fuel applications, fluorine materials are used in consideration of oil resistance.

  Next, embodiments of the present invention will be described with reference to the drawings.

First embodiment (related to claim 1) ...
FIG. 1 (A) shows a cross section of the main part of the sealing device 1 according to the first embodiment of the present invention. The sealing device 1 according to the embodiment is used for a high-pressure seal portion in an injector for an in-cylinder direct injection gasoline engine, and is configured as follows.

  That is, the sealing device 1 is arranged in an annular gap between the shaft 61 and the housing 62 as two members facing each other so that the sealing fluid existing in the right direction in the figure does not leak to the atmosphere side in the left direction in the figure. An O-ring 11 serving as a seal ring that is attached to an annular mounting groove 63 provided on the peripheral surface of the shaft 61 and is in close contact with the inner peripheral surface of the shaft hole of the housing 62, and an anti-sealing of the O-ring 11 A first backup ring 21 disposed on the fluid side and mounted in the mounting groove 63; a second backup ring 31 disposed between the O-ring 11 and the first backup ring 21 and mounted in the mounting groove 63; have. Instead of this, the O-ring 11 may be a seal ring having another cross-sectional shape such as a D ring or an X ring.

  The O-ring 11 is formed by a rubber-like elastic body. The first backup ring 21 is formed of, for example, nylon resin that is harder than the second backup ring 31. The second backup ring 31 is formed of, for example, PTFE resin that is softer than the first backup ring 21.

  The mounting groove 63 is a rectangular groove having a rectangular cross section, and no tapered shape is provided in the groove. Therefore, the mounting groove 63 has only a cylindrical groove-shaped groove bottom surface 63a and both side surfaces 63b having a plane perpendicular to the axis.

  The first backup ring 21 has an annular main body portion 22 having a rectangular cross section (a rectangular shape that is long in the radial direction), and is a side surface of the main body portion 22 on the O-ring 11 side and an inner peripheral end portion thereof. An annular projecting portion 23 is integrally formed, and a taper shape (also referred to as an inclined surface) 24 is provided on the outer peripheral surface of the projecting portion 23 such that the diameter dimension gradually decreases as the O-ring 11 is approached. Yes. Therefore, the projecting portion 23 has a triangular shape in cross section.

  On the other hand, the second backup ring 31 has a rectangular cross section as a whole (a rectangular shape that is long in the radial direction), and can run on the inner peripheral surface corresponding to the tapered shape 24 of the first backup ring 21. A tapered portion (also referred to as an inclined surface) 32 is provided. Therefore, like the tapered shape 24, the tapered portion 32 is formed in such a direction that the diameter dimension gradually decreases as it approaches the O-ring 11.

  The outer diameter dimension of the first backup ring 21 is set to be equal to or substantially equal to the diameter dimension of the inner peripheral surface of the shaft hole of the housing 62. The inner diameter dimension of the first backup ring 21 is set to be equal to or substantially equal to the diameter dimension of the groove bottom surface 63 a of the mounting groove 63.

  On the other hand, the outer diameter dimension of the second backup ring 31 is set to be equal to or substantially equal to the diameter dimension of the inner peripheral surface of the shaft hole of the housing 62. Further, the minimum inner diameter of the second backup ring 31 is set to be equal to or substantially equal to the diameter of the groove bottom surface 63 a of the mounting groove 63.

As shown in the figure, in the normal state, which is the initial state, the taper shape 24 and the taper portion 32 are arranged so as to overlap each other in the axial direction. However, an initial gap (axial gap) c ₁ having a predetermined size is set between the main body portion 22 of the first backup ring 21 and the second backup ring 31 so that it can be further climbed. ing.

In the sealing device 1 having the above configuration, when the high pressure P acts from the sealing fluid side, the O-ring 11 is pressed against the second backup ring 31, and the second backup ring 31 further rides on the tapered shape 24 of the first backup ring 21. Te initial clearance c ₁ is narrowed, the second backup ring 31, a shaft hole of the housing 62 at its outer peripheral surface with closely strongly at the tapered portion 32 of the inner peripheral surface of the tapered shape 24 of the first backup ring 21 Closely close to the inner surface. Therefore, according to the sealing device 1, excellent pressure resistance is exhibited, and the protrusion of the O-ring 11 can be effectively suppressed. Further, since the second backup ring 31 is softer than the first backup ring 21, even if the O-ring 11 is pressed against this, the surface of the O-ring 11 is not damaged. Further, since the mounting groove 63 is a simple rectangular groove, the groove processing is facilitated and the processing cost is reduced.

Second embodiment (related to claims 2 and 3) ...
FIG. 2A shows a cross-section of the main part of the sealing device 1 according to the second embodiment of the present invention. The sealing device 1 according to the embodiment is used for a high-pressure seal portion in an injector for an in-cylinder direct injection gasoline engine, and is configured as follows.

  That is, the sealing device 1 is arranged in an annular gap between the shaft 61 and the housing 62 as two members facing each other so that the sealing fluid existing in the right direction in the figure does not leak to the atmosphere side in the left direction in the figure. An O-ring 11 serving as a seal ring that is attached to an annular mounting groove 63 provided on the peripheral surface of the shaft 61 and is in close contact with the inner peripheral surface of the shaft hole of the housing 62, and an anti-sealing of the O-ring 11 A first backup ring 21 disposed on the fluid side and mounted in the mounting groove 63; a second backup ring 31 disposed between the O-ring 11 and the first backup ring 21 and mounted in the mounting groove 63; have. Instead of this, the O-ring 11 may be a seal ring having another cross-sectional shape such as a D ring or an X ring.

  The O-ring 11 is formed by a rubber-like elastic body. The first backup ring 21 is formed of, for example, nylon resin that is harder than the second backup ring 31. The second backup ring 31 is formed of, for example, PTFE resin that is softer than the first backup ring 21.

  The mounting groove 63 is a rectangular groove having a rectangular cross section, and no tapered shape is provided in the groove. Accordingly, the mounting groove 63 has only a cylindrical groove bottom surface 63a and both side surfaces 63b having a plane perpendicular to the axis.

  The first backup ring 21 has an annular main body portion 22 having a rectangular cross section (a rectangular shape that is long in the radial direction), and is a side surface of the main body portion 22 on the O-ring 11 side at the outer peripheral end portion. An annular projecting portion 23 is integrally formed, and a taper shape (also referred to as an inclined surface) 24 is provided on the inner peripheral surface of the projecting portion 23 so that the diameter dimension gradually increases as the O-ring 11 is approached. Yes. Therefore, the projecting portion 23 has a triangular shape in cross section.

  On the other hand, the second backup ring 31 has a rectangular cross section as a whole (a rectangular shape that is long in the radial direction), and can run on the inner peripheral surface corresponding to the tapered shape 24 of the first backup ring 21. A tapered portion (also referred to as an inclined surface) 32 is provided. Accordingly, the tapered portion 32 is formed in a direction in which the diameter dimension gradually increases as it approaches the O-ring 11, as in the tapered shape 24.

The outer diameter dimension of the first backup ring 21 is set to be equal to or substantially equal to the diameter dimension of the inner peripheral surface of the shaft hole of the housing 62. The inner diameter dimension of the first backup ring 21 is set to be larger than the diameter dimension of the groove bottom surface 63a of the mounting groove 63. Therefore, a predetermined distance is provided between the inner peripheral surface of the first backup ring 21 and the groove bottom surface 63a of the mounting groove 63. the size of the initial clearance (radial clearance) c ₂ is set.

  On the other hand, the maximum outer diameter dimension of the second backup ring 31 is set equal to or substantially equal to the diameter dimension of the inner peripheral surface of the shaft hole of the housing 62. Further, the inner diameter dimension of the second backup ring 31 is set to be equal to or substantially equal to the diameter dimension of the groove bottom surface 63 a of the mounting groove 63.

  In addition, as described above, the height dimension of the first backup ring 21 is set to a dimension that does not crush in the over-compressed state after the eccentricity, and the height dimension of the second backup ring 31 is the mounting groove 63 in the normal state. Are set in accordance with the height dimension (the distance dimension between the groove bottom surface 63a of the mounting groove 63 and the inner peripheral surface of the shaft hole of the housing 62), which will be described later.

As shown in the figure, in the normal state, which is the initial state, the taper shape 24 and the taper portion 32 are arranged so as to overlap each other in the axial direction. However, an initial gap (axial gap) c ₁ having a predetermined size is set between the main body portion 22 of the first backup ring 21 and the second backup ring 31 so that it can be further climbed. ing.

In the sealing device 1 having the above configuration, when the high pressure P acts from the sealing fluid side, the O-ring 11 is pressed against the second backup ring 31, and the second backup ring 31 further rides on the tapered shape 24 of the first backup ring 21. Thus, the initial gap c ₁ is narrowed, and the second backup ring 31 is closely in close contact with the tapered shape 24 of the first backup ring 21 at the tapered portion 32 of the outer peripheral surface, and the groove of the mounting groove 63 on the inner peripheral surface thereof. Strongly in close contact with the bottom surface 63a. Therefore, according to the sealing device 1, excellent pressure resistance is exhibited, and the protrusion of the O-ring 11 can be effectively suppressed. Further, since the second backup ring 31 is softer than the first backup ring 21, even if the O-ring 11 is pressed against this, the surface of the O-ring 11 is not damaged. Further, since the mounting groove 63 is a simple rectangular groove, the groove processing is facilitated and the processing cost is reduced.

  When the first and second embodiments are compared, there are the following differences.

  That is, in the sealing device 1 according to the first embodiment, when the shaft 61 is eccentric, as shown in the upper half of FIG. Since 31 is a soft material, it deforms and fills the gap with the housing 62. On the non-compression side on the circumference, as shown in the lower half of FIG. 1B, the second backup ring 31 rides on the tapered shape 24 of the first backup ring 21 and fills the gap with the housing 62. .

However, since the first backup ring 21 is a hard material and is not easily deformed, when the eccentric amount is large, as shown in the upper half of FIG. May hit against the housing 62 and crack (the interference portion is indicated by reference numeral 25). On the non-compression side, as shown in the lower half of FIG. 1B, a gap c ₃ is generated between the first backup ring 21 and the housing 62, so that the second backup ring 31 is connected to the shaft 61. There is a possibility that the gap 64 between the housing 62 and the housing 62 protrudes greatly.

On the other hand, in the sealing device 1 according to the second embodiment, as described above, the height dimension of the first backup ring 21 is set to a dimension that does not crush in the overcompressed state after eccentricity. In addition, as shown in the upper half of FIG. 2B, the first backup ring 21 is not crushed and cracked even on the overcompressed side, and is shown in the lower half of FIG. 2B on the non-compressed side. As described above, since no gap is generated between the first backup ring 21 and the housing 62, it is possible to effectively prevent the second backup ring 31 from protruding (in this case, the inner circumference of the first backup ring 21). a gap c ₄ between the surface and the groove bottom surface 63a of the mounting groove 63 is formed, there is a possibility that the second backup ring 31 protrudes here, the side surface of the gap c ₄ is the mounting groove 63 63 Because it is above blind-like space is blocked by, but not the second backup ring 31 protrudes significantly).

  Therefore, when comparing the first and second embodiments, it can be said that the second embodiment is superior in that it can prevent the second backup ring 31 from protruding greatly.

1 Sealing device 11 O-ring (seal ring)
21 First backup ring 22 Body portion 23 Overhang portion 24 Tapered shape 25 Interference portion 31 Second backup ring 32 Tapered portion 61 Shaft (one member)
62 housing 63 mounting groove 63a groove bottom surface 63b side _{64, c 1, c 2,} c 3, c 4 gap

Claims (3)

A sealing device disposed between two members facing each other for sealing a sealing fluid,
A seal ring mounted in a mounting groove provided in one of the two members and in close contact with the other member; a relatively hard first backup ring disposed on the anti-sealing fluid side of the seal ring; A relatively soft second backup ring disposed between the seal ring and the first backup ring;
The mounting groove is a rectangular groove having a rectangular cross section,
The first backup ring integrally includes an annular main body part and an overhang part provided on a seal ring side surface of the main body part and close to a groove bottom surface of the mounting groove, and the overhang part A tapered shape that is inclined in a direction approaching the groove bottom as it approaches the seal ring;
The second backup ring is provided with a tapered portion capable of riding on the taper shape of the first backup ring,
An sealing device, wherein an initial gap is set between the main body of the first backup ring and the second backup ring. A sealing device disposed between two members facing each other for sealing a sealing fluid,
A seal ring mounted in a mounting groove provided in one of the two members and in close contact with the other member; a relatively hard first backup ring disposed on the anti-sealing fluid side of the seal ring; A relatively soft second backup ring disposed between the seal ring and the first backup ring;
The mounting groove is a rectangular groove having a rectangular cross section,
The first backup ring integrally has an annular main body portion and a projecting portion provided on a portion close to the other member on the seal ring side surface of the main body portion. A tapered shape is provided that is inclined in a direction approaching the other member as the seal ring is approached,
The second backup ring is provided with a tapered portion capable of riding on the taper shape of the first backup ring,
An sealing device, wherein an initial gap is set between the main body of the first backup ring and the second backup ring. The sealing device according to claim 2.
The height dimension of the first backup ring is set to a dimension that does not crush in the over-compressed state after eccentricity,
The height of the second backup ring is normally set in accordance with the height of the mounting groove.

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