CN214946369U - Sealing ring - Google Patents

Abstract

The utility model provides a sealing ring, the damage of joint opposite part when it can prevent to install the sealing ring can reduce and reduce the friction torque with the area of contact of the cyclic annular groove side of rotation axis. The seal ring at least comprises: an annular seal ring main body (1A) having a joint section (15); and a reinforcement portion (17) formed in the seal ring main body (1A) at a joint opposing portion (16) opposing the joint portion (15), the reinforcement portion (17) being formed at an inner peripheral surface of the seal ring main body (1A) so as to protrude radially inward, a cross-section of the joint opposing portion (16) along an axis of the seal ring main body (1A) being formed in a T-shape protruding radially inward by the reinforcement portion (17).

Description

Sealing ring

Technical Field

The present invention relates to a seal ring, and, for example, to a seal ring used in an Automatic Transmission (AT) of an automobile for sealing lubricating oil in a gap between a rotating shaft and a housing.

Background

For example, a plurality of seal rings are used in an Automatic Transmission (AT) for an automobile. The annular seal ring 100 shown in fig. 9 and 10 is assembled between the rotary shaft 300 and the housing 200 that move relatively in the hydraulic circuit of the transmission, and functions to seal the lubricating oil while sliding.

As shown in fig. 10 and 11, the seal ring 100 is mounted in an annular groove 301 formed in the outer peripheral surface 300a of the rotary shaft 300, and seals an annular gap 400 between the housing 200 and the rotary shaft 300 assembled in the housing 201.

As shown in fig. 9, in the seal ring 100, protruding pieces 101 protruding radially inward may be provided at a plurality of positions on the inner circumferential surface 100a of the seal ring 100. The protruding piece 101 is used to prevent the center of the seal ring 100 from being largely deviated from the center of the rotary shaft by bringing the tip end thereof into contact with the groove bottom surface of the annular groove 301 when the rotary shaft 300 is assembled in the housing 200.

As described above, the seal ring 100 is mounted in the annular groove 301 provided in the outer peripheral surface 300a of the rotary shaft 300, and the outer peripheral surface 100b thereof is brought into contact with the inner peripheral surface 201 of the housing 200 by the pressure P of the lubricating oil received from the oil supply side (the annular gap 400 side), as shown in fig. 11. Further, a side surface 100c on the oil seal side (the annular gap 401 side) of the seal ring 100 is in sliding contact with a side wall surface 301a of the annular groove 301. Thereby, the lubricating oil is prevented from leaking to the oil seal side.

Further, the side surface 100c of the seal ring which is in sliding contact with the side wall surface 301a of the annular groove 301 slides with respect to the side wall surface 301a of the annular groove 301 by the rotation of the rotary shaft 300. The seal ring 100 is formed in a T-shape in cross section, for example. Thus, a force in a direction in which the side surface 100c of the seal ring 100 is separated from the side wall surface 301a of the annular groove 301 is exerted by the pressure of the lubricating oil that has entered between the non-seal surface 100d and the side wall surface 301a of the annular groove 301. As a result, the sliding frictional force generated between the side surface 100c of the seal ring 100 and the side wall surface 301a of the annular groove 301 is reduced, and the frictional torque generated by the sliding with the side wall surface 301a of the annular groove 301 is reduced.

However, as shown in fig. 9, the seal ring 100 is partially cut (at the joint portion 102), and when being mounted on a rotary shaft or the like, the joint portion 102 is enlarged and mounted. At this time, the facing portion 103 of the seal ring of the joint portion 102 is strained, and high stress is generated. Therefore, if there is an injection molding gate in the opposing portion 103, the strength of the portion becomes weak, and there is a problem that the seal ring is broken when mounted on a rotating shaft or the like. In order to solve such a problem, in the invention disclosed in japanese patent application laid-open No. 2004-205003, as shown in fig. 12, the gate position 153 is shifted from the facing portion 152 in the seal ring 150, thereby suppressing a decrease in strength at the facing portion 152.

In this method, since the flow length and the volume from the gate position 153 to the joint portion 151 (cut ends at both ends of the seal ring) are different, if the filling amount of the molten resin is adjusted to the side having a short flow length, the filling shortage occurs at the side having a long flow length, whereas if the filling amount is adjusted to the side having a long flow length, the side having a short flow length becomes the filling shortage, and the burr is likely to occur. Therefore, in the seal ring 150 shown in japanese patent application laid-open No. 2004-205003, after the gate 153 is disposed at a position shifted from the opposing portion 152 on the seal ring 150 of the joint portion 151, the resin reservoir 154 is provided at the side T1 where the distance between the gate 153 and the joint portion 151 is short. Thus, the resin filling amount at the side T2 where the distance between gate 153 and connecting part 151 is longer is the same as the resin filling amount at the side T1 where the distance from gate 153 to connecting part 151 is shorter. According to this structure, when the seal ring is mounted on the rotary shaft or the like, the seal ring is not damaged by enlarging the joint portion, and occurrence of troubles such as burrs can be prevented.

However, in the structure of the seal ring disclosed in japanese patent application laid-open No. 2004-205003, the resin reservoir 154 must be removed with high accuracy after injection molding of the seal ring, which requires more man-hours and materials and is costly.

On the other hand, japanese patent application laid-open No. 2008-157397 discloses the following structure: as shown in fig. 13 a and 13B (a cross-sectional view taken along line B-B of fig. 13 a), in the seal ring 160 having the joint portion 161 cut at one position in the circumferential direction, a thick-walled portion 163 having a convex shape toward the inside in the radial direction is provided in a vicinity of the joint opposing portion 162 opposing the joint portion 161 on the seal ring 160.

The inner diameter side of the thick portion 163 is connected to the thin adjacent regions on both sides in a smooth tapered shape. In this way, by using the thick portion 163 in which the vicinity region including the joint counterpart 162 is convex in the radial direction, the strength of the vicinity region including the joint counterpart 162 is greatly improved. Thus, when the seal ring is mounted on a rotary shaft or the like, the seal ring can be prevented from being damaged by enlarging the joint portion. Further, a gate position may be provided at the joint opposing portion 162, and it is not necessary to provide a resin reservoir portion as in the seal ring disclosed in japanese patent application laid-open No. 2004-205003.

However, the thick portion provided in the seal ring shown in jp 2008-157397 a and protruding inward in the radial direction of the seal ring has a shape that is smaller in diameter from the center of the seal ring than the seal ring main body and is long and continuous in the circumferential direction.

Therefore, there is a problem that a contact area S (see fig. 13 b) with the annular groove side wall surface of the rotating shaft to which the seal ring is assembled becomes large and a friction torque becomes large.

Further, although the inner diameter side of the thick-walled portion is connected with the thin-walled adjacent regions on both sides in a smoothly tapered shape, bending stress is concentrated at the connecting portion, and permanent deformation or damage may occur.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a sealing ring, the sealing ring is used for sealing up the casing and assembles the annular clearance between its inside rotation axis, can prevent the damage of the joint opposite parts when installing the sealing ring on the rotation axis, can reduce the friction torque with the cyclic annular groove lateral wall face of rotation axis.

In order to solve the problem, according to the utility model discloses a sealing ring, its characterized in that includes at least: an annular seal ring main body having a joint portion; and a reinforcement portion formed in the seal ring main body at a joint opposing portion opposing the joint portion, the reinforcement portion being formed at an inner peripheral surface of the seal ring main body so as to protrude radially inward, a shape of a cross section of the joint opposing portion along an axis of the seal ring main body being formed in a T-shape protruding radially inward by the reinforcement portion.

Here, it is desirable that a protrusion portion protruding toward the radially inner side be provided at the inner peripheral surface of the seal ring main body in the vicinity of the joint portion, and a radial thickness of the reinforcement portion at a portion opposed to the joint portion is the same as a radial thickness of the protrusion portion.

Further, it is desirable that the reinforcement portion is curved to have a single radius of curvature larger than that of the seal ring main body in the circumferential direction.

Further, it is desirable that, at the circumferential center of the joint opposing portion, a ratio a1: a2 of a radial thickness a2 of the reinforcement portion to a radial thickness a1 of the seal ring main body is 1:0.15 to 1: 0.5.

Further, it is desirable that a ratio h1: h2 of an axial height h2 of the reinforcement portion to an axial height h1 of the seal ring main body is 1:0.6 to 1: 0.9.

Further, it is desirable that the reinforcement portion has a centering function together with the protrusion portion, that is, when the seal ring main body is mounted at the annular groove formed at the rotating shaft, the center of the seal ring main body is prevented from being largely deviated from the center of the rotating shaft by abutting against a groove bottom surface of the annular groove.

According to the utility model discloses a sealing ring has reinforcement, reinforcement is protruding towards radial inboard at the joint opposite part department of sealing ring. The joint counterpart having the reinforcement portion has a T-shaped cross-section along the axis of the seal ring. This makes the joint opposing portion thicker, and prevents damage to the joint opposing portion when the seal ring is attached to the rotary shaft (when the joint portion is enlarged).

Further, since the cross-sectional shape along the axis of the seal ring of the joining opposing portion having the reinforcement portion is formed in the T-shape, as described in the background art, by the pressure of the lubricating oil that is wound between the non-seal surface and the side wall surface of the annular groove, a force acts in a direction in which the side surface of the seal ring is separated from the side wall surface of the annular groove, whereby the sliding frictional force generated between the side surface of the seal ring and the side wall surface of the annular groove is reduced, and the frictional torque generated by the sliding with the side wall surface of the annular groove can be reduced as compared with the case of the rectangular shape that protrudes radially inward.

According to the present invention, a seal ring can be obtained, which is used to seal an annular gap between a housing and a rotating shaft assembled inside the housing, and which can prevent damage to a joint counterpart portion when the seal ring is mounted on the rotating shaft, and which can reduce a friction torque with an annular groove side wall surface of the rotating shaft.

Drawings

Fig. 1 is a perspective view of a seal ring according to an embodiment of the present invention.

Fig. 2 is a perspective view of the seal ring shown in fig. 1 viewed from another direction.

Fig. 3 (a) is a plan view of the seal ring of fig. 1, and fig. 3 (b) is a side view of the seal ring.

Fig. 4 is a sectional view showing a state where the seal ring of the present invention is mounted in the annular groove of the rotary shaft.

Fig. 5 (a) is a partially enlarged plan view of a region of the seal ring including the reinforcement portion, fig. 5 (b) is a cross-sectional view taken along line a-a of fig. 5 (a), and fig. 5 (c) is a perspective view of the reinforcement portion.

Fig. 6 (a) is a plan view of the engagement portion and the protruding piece in the vicinity thereof as viewed in an enlarged manner, fig. 6 (b) is a side view of the engagement portion as viewed from the outside of the seal ring, and fig. 6 (c) is a perspective view of the engagement portion and the protruding piece in the vicinity thereof as viewed in an enlarged manner.

Fig. 7 is a perspective view showing another form of the reinforcement portion.

Fig. 8 is a perspective view showing another form of the reinforcement portion.

Fig. 9 is a perspective view of a conventional seal ring.

Fig. 10 is a sectional view of a state where a conventional seal ring is mounted.

Fig. 11 is a partially enlarged view of fig. 10.

Fig. 12 is a plan view of a conventional seal ring.

Fig. 13 (a) is a plan view of another conventional seal ring, and fig. 13 (B) is a sectional view taken along line B-B of fig. 13 (a).

Detailed Description

Hereinafter, embodiments of the seal ring according to the present invention will be described with reference to the drawings. The seal ring according to the present embodiment is incorporated between a rotary shaft and a housing that move relatively in a hydraulic circuit of an automatic transmission of an automobile, for example, and functions to seal lubricating oil while sliding.

Fig. 1 is a perspective view of a seal ring according to an embodiment of the present invention, and fig. 2 is a perspective view of the seal ring shown in fig. 1 as viewed from another direction. Fig. 3 (a) is a plan view of the seal ring of fig. 1 and 2, and fig. 3 (b) is a side view of the seal ring. Fig. 4 is a cross-sectional view showing a state in which the seal ring of the present invention is mounted in the annular groove of the rotary shaft.

The illustrated seal ring 1 is formed of a material in which filler fibers such as carbon fibers as a reinforcing material are blended with resin Polyamide (PA) such as PEEK and PPS, a fluororesin (polytetrafluoroethylene (4 fluoride) (PTFE), a tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer (PFA), a tetrafluoroethylene/ethylene copolymer (ETFE), an alloy material thereof, a Liquid Crystal Polymer (LCP), Polyimide (PI), polyether ketone (PEK), polyarylether ketone (PAEK), polyether ketone ether ketone (PEKEKK), super engineering plastic represented by polyether ether ketone (PEEK) and polyphenylene sulfide (PPS), Polybenzimidazole (PBI), and the like.

The seal ring 1 includes: an annular seal ring main body 1A for sealing a gap between the housing and the rotating shaft; a plurality of tabs (protrusions) 10 formed at the inner peripheral surface of the seal ring main body 1A; and a reinforcing portion 17 formed in the vicinity including the joint opposing portion 16.

The seal ring main body 1A is formed to have a rectangular cross section at a portion where the protruding piece 10 and the reinforcing portion 17 are not formed.

Specifically, as shown in fig. 4, the seal ring main body 1A has a first seal surface 2 on the oil seal side (seal surface side). The first seal surface 2 is in sliding contact with a side wall surface (oil seal side surface of the annular groove) 21a of the annular groove 21 of the rotary shaft 20, and seals the side wall surface 21 a.

Further, a second seal surface 5 is formed on the outer peripheral surface of the seal ring main body 1A. The second seal surface 5 is in contact with the inner peripheral surface 31 of the housing 30 to perform sealing.

As shown in fig. 4, a non-seal surface 6 and an inner circumferential surface 7 are formed on the oil supply side surface and the inner circumferential surface of the seal ring main body 1A, respectively.

As described above, at the inner peripheral surface 7 of the seal ring 1 shown in fig. 1 to 3, a plurality of (6 in the drawing, as shown in fig. 3) tabs 10 are provided at predetermined intervals. The tab 10 is also formed near the engaging portion.

As one of the functions, the protruding piece 10 has a centering function of preventing the center O of the seal ring main body 1A from being greatly deviated from the center of the shaft 20 when the rotary shaft 20 is assembled inside the housing 30.

That is, when the seal ring body 1A is offset from the center of the rotary shaft 20 when the seal ring 1 is mounted in the annular groove 21 of the rotary shaft 20, the tip end portion 10a of the protruding piece 10 abuts on the groove bottom surface 21b of the annular groove 21. By the abutment, the center O of the seal ring main body 1A is prevented from largely deviating from the center of the rotary shaft 20. That is, the protruding piece 10 has a centering function of correcting the center deviation between the seal ring main body 1A and the rotary shaft 20.

Therefore, as shown in fig. 3, the protruding pieces 10 protrude radially inward from the inner peripheral surface 7, the seal ring 1 is mounted in the annular groove 21 of the rotary shaft 20, and when the seal ring body 1A is offset from the rotary shaft 20, the tip end portions 10a of the protruding pieces 10 abut against the groove bottom surface 21b of the annular groove 21.

Further, as shown in fig. 1 to 3, an engaging portion 15 (a separating portion) is formed at one position in the circumferential direction of the seal ring 1, and when attached to the rotary shaft 20, the seal ring 1 can be easily attached to the annular groove 21 of the rotary shaft 20 by enlarging the seal ring 1 in a direction of separating the engaging portion 15.

When the seal ring 1 is mounted on the rotary shaft 20, if the seal ring 1 is enlarged in a direction of separating the joint portion 15, a high stress is generated in the joint opposing portion 16, which is an opposing portion of the seal ring of the joint portion 15. Therefore, the seal ring 1 includes the reinforcement portion 17, and the reinforcement portion 17 protrudes radially inward in the vicinity area including the engagement opposing portion 16.

Fig. 5 (a) is a partially enlarged plan view of the region of the seal ring including the reinforcement portion 17, and fig. 5 (b) is a sectional view taken along line a-a of fig. 5 (a). Further, (c) in fig. 5 shows a perspective view of the reinforcement portion 17.

As shown in fig. 5 (b), the cross-sectional shape along the axis of the seal ring main body 1A having the joint opposing portion of the reinforcement portion 17 is formed in a T shape protruding radially inward. This thickens the joint counterpart 16, and prevents the joint counterpart 16 from being damaged when the seal ring body 1A is mounted on the rotary shaft (when the joint 15 is enlarged).

As shown in fig. 5 (b), the cross-sectional shape of the joint counterpart 16 including the reinforcement 17 is a so-called T-shaped cross-sectional shape obtained by removing the thickness (a2), the upper side rectangular cross-section of the height ((h1-h2)/2), the thickness (a2), and the lower side rectangular cross-section of the height (h1-h2)/2) from the rectangular cross-sections of the thickness (a1+ a2) and the height (h 1).

As described in the background art (see fig. 11), a force acts in a direction in which the side surface 100c of the seal ring 100 is separated from the side wall surface 301a of the annular groove 301 by the pressure of the lubricating oil that has entered between the non-seal surface 100d and the side wall surface 301a of the annular groove 301. This reduces the sliding friction force generated between the side surface 100c of the seal ring 100 and the side surface 301a of the annular groove 301.

In this seal ring 1, since the joint counterpart 16 is formed in a T-shape in cross section, the frictional torque generated by sliding with the side surface 301a of the annular groove 301 can be reduced as compared with the case where the cross-sectional shape is rectangular (rectangular with a height of h1, radial thickness (a1+ a 2)).

Further, the engagement opposing portion 16 formed in a T-shaped cross-sectional shape has a centering function as the protruding piece 10, that is, when the rotary shaft 20 is assembled inside the housing 30, the center O of the seal ring main body 1A is prevented from being largely deviated from the center of the rotary shaft 20.

When the rectangular cross section having the thickness (a1+ a2) and the height (h1) is compared with the T-shaped cross section, the second moment of area of the T-shaped cross section is smaller than the second moment of area of the rectangular cross section. Therefore, when the joint portion is enlarged by the same length, the joint portion can be enlarged with a smaller force than the case of the rectangular cross section.

As shown in fig. 5 (a) and 5 (c), the reinforcing portion 17 includes: a reinforcement part main body 17a having the same single radius of curvature as the seal ring main body 1A in plan view; and connecting portions 17b, on both sides of the reinforcing portion main body 17a in the circumferential direction, whose inner diameter side surfaces are connected to the inner circumferential surface of the seal ring main body 1A.

The connecting portion 17b is formed by two curved portions 17b1, 17b2 that are curved in a concave shape in series, and each of the curved portions 17b1, 17b2 is formed to have a radius of curvature larger than that of the seal ring main body 1A in the circumferential direction.

When the radius of curvature of the curved portions 17b1, 17b2 is smaller than the radius of curvature of the seal ring main body 1A in the circumferential direction, a step is generated at the connecting portion 17b of the reinforcement portion 17 with the seal ring main body 1A, bending strain (bending stress) is concentrated at the step, and permanent deformation or breakage may occur.

On the other hand, when the radius of curvature of the curved portions 17b1 and 17b2 is larger than the radius of curvature of the seal ring main body 1A in the circumferential direction, a step is less likely to occur, and permanent deformation and breakage can be suppressed.

Further, as shown in fig. 5 (b), at the circumferential center of the joint opposing portion 16, the ratio a1: a2 of the radial thickness a2 of the reinforcing portion 17 to the radial thickness a1 (width dimension) of the seal ring main body 1A is formed to be 1:0.15 to 1: 0.5.

If importance is attached to the centering function, it is desirable that the radial thickness a2 of the reinforcement portion 17 is formed to be equal to the radial thickness of the tab 10.

In this way, when the radial thickness a2 of the reinforcing portion 17 and the radial thickness of the tab 10 are formed to be equal to each other, the reinforcing portion 17 also exhibits the centering function in the same manner as the tab 10.

In the case where the ratio of the radial thickness a2 of the reinforcement portion 17 is small (in the case where the ratio of the radial thickness a1 of the seal ring main body 1A is large), there is a possibility that damage of the joint counterpart portion cannot be prevented when the seal ring main body 1A is mounted to the annular groove 21 of the rotary shaft 20 (when the joint portion is enlarged).

On the other hand, when the ratio of the radial thickness a2 of the reinforcement portion 17 is large, the radial thickness a1 of the seal ring main body 1A becomes small, and therefore the strength of the seal ring main body 1A may become small.

Further, the ratio of the axial height h2 of the reinforcement portion 17 to the axial height h1 of the seal ring main body 1A is formed to be 1:0.6 to 1: 0.9.

When the ratio of h2 is large, the reinforcing portion 17 becomes the same surface as the first seal surface 2 due to the wear of the first seal surface 2, and as a result, the sliding resistance may be increased. Further, the sealing performance may be deteriorated by interference with the groove bottom surface 21b of the annular groove 21 of the rotary shaft 20.

When the ratio of h2 is small, the reinforcing effect is reduced by the ratio, and there is a possibility that a sufficient reinforcing effect cannot be secured, so that it is necessary to increase the ratio within a range in which there is no influence of the increase in sliding resistance.

In addition, in the case where the gate 153 (fig. 12) is provided at the joint counterpart 16, the strength of the joint counterpart 16 is reduced by about 30% to 50% with respect to the strength of the seal ring main body 1A due to the presence of the gate 153. However, by providing the reinforcing portion 17 at the joint counterpart 16, the bending rigidity (second moment of area) of 140% to 200% is reinforced, and the strength drop of the joint counterpart 16 due to the presence of the gate 153 can be offset.

Fig. 6 (a) is a plan view of the joint 15 and the protruding piece 10 in the vicinity thereof, as viewed in an enlarged manner, and fig. 6 (b) is a side view of the joint 15 as viewed from the outside of the seal ring 1. Fig. 6 (c) is an enlarged perspective view of the joint 15 and the protruding piece 10 in the vicinity thereof.

The joint 15 has engaging convex portions 15a1, 15b1 and engaging concave portions 15a2, 15b2, which are formed so as to be engageable with each other and have a smaller axial cross-sectional area than the seal ring body 1A.

The engaging convex portion 15a1 is engaged with the engaging concave portion 15b2, and the engaging convex portion 15b1 is engaged with the engaging concave portion 15a2, thereby closing the joint portion 15.

The seal ring 1 configured as described above is obtained by normal injection molding in which a molten resin is injected into a mold (not shown). A gate into which the resin flows in the mold is formed at a facing portion on the seal ring of the joint portion 15.

In injection molding, a molten resin injected from an injection nozzle (not shown) flows into a mold through a gate of the mold, and is divided into left and right sides and flows toward a formation portion of the joint portion 15 at a predetermined injection pressure. The molten resin flowing from the gate to the left and right sides also flows into the formation position of the protruding piece 10 in the formation portion of the protruding piece 10.

The liquid flows into a position where a reinforcing portion 17 protruding radially inward is formed at the joint opposing portion 16 of the seal ring 1, and the seal ring 1 including the reinforcing portion 17 is molded.

As described above, according to the embodiment of the present invention, the seal ring 1 has the reinforcement portion 17 protruding radially inward at the joint opposing portion 16. The joint counterpart 16 having the reinforcement portion 17 is formed in a T-shape protruding radially inward along a cross section of the shaft of the seal ring 1. This increases the thickness of the joint counterpart 16, and prevents damage to the joint counterpart 16 when the seal ring 1 is mounted in the annular groove 21 of the rotary shaft 20 (when the joint 15 is enlarged).

Further, as described in the background art (see fig. 11), since the joint counterpart 16 is formed in a T-shape in cross section, a force in a direction in which the side surface 100c of the seal ring 100 is separated from the side wall surface 301a of the annular groove 301 acts by the pressure of the lubricating oil that has entered between the non-seal surface 100d and the side wall surface 301a of the annular groove 301. As a result, the sliding friction force generated between the side surface 100c of the seal ring 100 and the side surface 301a of the annular groove 301 is reduced, and the friction torque generated by the sliding with the side surface of the annular groove can be reduced as compared with the case where the cross-sectional shape is rectangular (rectangular with a height of h1 and a thickness in the radial direction (a1+ a 2)).

In addition, in the above embodiment, the shape having the continuous curved portions 17b1, 17b2 in the connecting portion 17b of the reinforcing portion 17 is shown, but the present invention is not limited to this form. For example, as shown in the perspective view of fig. 7, the connecting portion 17b of the reinforcing portion 17 may be a single bent portion.

As shown in fig. 8, the reinforcing portion main body 17a may be formed in a linear shape (planar shape) on the inner diameter side (inner surface) without providing the connecting portion 17 b.

Claims (5)

1. A sealing ring, characterized by comprising at least:

an annular seal ring main body having a joint portion; and

a reinforcement portion formed in the seal ring main body at a joint opposing portion opposing the joint portion,

the reinforcement portion is formed on the inner peripheral surface of the seal ring main body so as to protrude radially inward, and the reinforcement portion forms a T-shape in a cross section along the axis of the seal ring main body in the joint opposing portion so as to protrude radially inward.

2. The seal ring of claim 1,

a protruding portion that protrudes radially inward is provided at an inner peripheral surface of the seal ring main body in the vicinity of the joint portion,

the radial thickness of the reinforcement portion at a portion opposite to the joint portion is the same as the radial thickness of the protrusion portion.

3. The seal ring of claim 1, wherein the reinforcement is curved to have a single radius of curvature in a circumferential direction that is greater than a radius of curvature of the seal ring body.

4. The seal ring according to claim 1 or 2, wherein a ratio a 1a 2 of a radial thickness a2 of the reinforcement portion to a radial thickness a1 of the seal ring main body is 1:0.15 to 1:0.5 at a circumferential center of the joint opposing portion.

5. The seal ring of any one of claims 1 to 4, wherein a ratio h1: h2 of an axial height h2 of the reinforcement portion to an axial height h1 of the seal ring body is 1:0.6 to 1: 0.9.

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