Sealing ring

Abstract

This sealing ring comprises: a first ring having an inner circumferential surface and an outer tapered surface that is inclined with respect to the inner circumferential surface; and a second ring having an outer circumferential surface and an inner tapered surface that is inclined with respect to the outer circumferential surface and that faces the outer tapered surface. One of the first ring and the second ring is formed of a first resin having a flexural modulus of less than 700 MPa, and the other is formed of a second resin having a flexural modulus of at least 700 MPa. When the first ring is formed of the first resin, the seal ring seals fluid on the outer circumferential surface side of the second ring. When the second ring is formed of the first resin, the seal ring seals fluid on the inner circumferential surface side of the first ring.

Description

Sealing ring

[0001] The present invention relates to a sealing ring.

[0002] Generally, a sealing ring is pressed against a mating member by the pressure of the fluid to be sealed, thereby preventing the entry of the fluid between the mating member. However, a low-viscosity fluid (especially gas) that can enter even through a small gap will enter between the sealing ring and the mating member before the sealing ring is pressed against the mating member. Therefore, such a sealing ring may not be able to exhibit sufficient sealing performance initially.

[0003] On the other hand, Patent Documents 1 and 2 disclose techniques for pressing a sealing ring against a mating member before the pressure of the fluid is generated. In these techniques, a metal coil expander for pressing the sealing ring from the inside is provided. In these techniques, the sealing ring is pressed against the mating member by the pressure generated by the coil expander to expand the diameter of the sealing ring, so high sealing performance can be easily obtained from the beginning.

[0004] Japanese Utility Model Publication No. 55-94440, Japanese Patent Application Laid-Open No. 2014-178037

[0005] In the technique using the above-mentioned coil expander, it is difficult to generate a pressure by the coil expander such that sufficient sealing performance can be obtained even for a low-viscosity fluid. Further, in the technique using the above-mentioned metal coil expander, since the coil expander and the shaft groove are in metal contact, abnormal wear of the mating member and abnormal wear of the sealing ring due to metal powder generated accordingly may occur.

[0006] In view of the above circumstances, an object of the present invention is to provide a sealing ring that can obtain high sealing performance even for a low-viscosity fluid.

[0007] A seal ring according to one embodiment of the present invention comprises a first ring having an inner circumferential surface and an outer tapered surface inclined with respect to the inner circumferential surface, and a second ring having an outer circumferential surface and an inner tapered surface inclined with respect to the outer circumferential surface and facing the outer tapered surface. Of the first ring and the second ring, one is formed of a first resin having a flexural modulus of less than 700 MPa, and the other is formed of a second resin having a flexural modulus of 700 MPa or more. When the first ring is formed of the first resin, the seal ring seals the fluid on the outer circumferential surface side of the second ring. When the second ring is formed of the first resin, the seal ring seals the fluid on the inner circumferential surface side of the first ring.

[0008] This seal ring consists of a main ring, one of which is made of a soft first resin, and a backup ring, the other of which is made of a hard second resin. This seal ring can exhibit high sealing performance even for low-viscosity fluids such as gases by compressing and deforming the soft main ring between the outer or inner tapered surface of the hard backup ring and the mating material.

[0009] If the first ring is formed of the first resin, the first ring may further have a joint portion comprising a first engaging portion having a first inclined surface that is inclined with respect to the inner circumferential surface in the same direction as the outer tapered surface and extends at a distance from the outer tapered surface, and a second engaging portion having a second inclined surface that faces the first inclined surface.

[0010] If the second ring is formed of the first resin, the second ring may further have a joint portion comprising a first engaging portion having a first inclined surface that is inclined with respect to the outer circumferential surface in the same direction as the inner tapered surface and extends at a distance from the inner tapered surface, and a second engaging portion having a second inclined surface that faces the first inclined surface.

[0011] The fluid may be a gas.

[0012] As described above, the present invention provides a seal ring that can achieve high sealing performance even with low-viscosity fluids.

[0013] This is a plan view of a seal ring according to the first embodiment of the present invention. This is a cross-sectional view of the seal ring shown in Figure 1 along the line A-A'. This is a cross-sectional view showing the seal ring shown in Figure 1 assembled to the movable scroll and housing. This is a partial perspective view showing the joint of the main ring of the seal ring shown in Figure 1. This is a cross-sectional view of the main ring shown in Figure 4 along the line B-B'. This is a plan view of a seal ring according to the second embodiment of the present invention. This is a cross-sectional view of the seal ring shown in Figure 6 along the line C-C'. This is a cross-sectional view showing the seal ring shown in Figure 6 assembled to the movable scroll and housing. This is a partial perspective view showing the joint of the main ring of the seal ring shown in Figure 6. This is a cross-sectional view of the main ring shown in Figure 9 along the line D-D'. This is a cross-sectional view showing the seal ring according to the third embodiment of the present invention assembled to the shaft and cylinder. This is a graph showing the leakage reduction rate at each atmospheric pressure for samples according to Examples 1-1 and 1-2. This is a graph showing the leakage reduction rate at each atmospheric pressure for samples according to Examples 2-1 and 2-2.

[0014] [Introduction] Embodiments of the present invention will be described with reference to the drawings. One embodiment of the seal ring can be used to seal the gap between a movable scroll and a housing in a scroll compressor. In this case, the configuration of the seal ring that seals the fluid on the outer circumference (first embodiment) and the configuration of the seal ring that seals the fluid on the inner circumference (second embodiment) are different from each other. The seal ring according to one embodiment can also be used to seal the gap between a shaft and a cylinder that reciprocate relatively (third embodiment). In any of the seal ring embodiments, the fluid to be sealed is a liquid or a gas, typically a gas such as air, nitrogen, or oxygen.

[0015] [First Embodiment] The seal ring 100 according to the first embodiment of the present invention is configured to seal the fluid F on the outer circumference. Figure 1 is a plan view of the seal ring 100. Figure 2 is a cross-sectional view of the seal ring 100 along the line A-A' in Figure 1. The seal ring 100 has a main ring 110 which is a first ring and a backup ring 120 which is a second ring. The main ring 110 and the backup ring 120 have a common central axis C and are superimposed on each other in the direction of the central axis C. The diameter of the backup ring 120 is slightly larger than the diameter of the main ring 110.

[0016] The backup ring 120 is made of a harder resin than the main ring 110. Specifically, the main ring 110 is made of a first resin with a flexural modulus of less than 700 MPa. Examples of the first resin include polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), fluororubber (FKM), and hydrogenated nitrile rubber (HNBR). The backup ring 120 is made of a second resin with a flexural modulus of 700 MPa or more. The flexural modulus of the second resin is preferably 1000 MPa or more, and more preferably 1500 MPa or more. Examples of the second resin include polyetheretherketone (PEEK), polyphenylene sulfide (PPS), nylon 66, polyphenol (PF), polyethylene terephthalate (PBT), polyimide (PI), polyamideimide (PAI), polyacetal (POM), and polyphthalamide (PPA).

[0017] The main ring 110 has an inner circumferential surface 111, a first side surface 112, and an outer tapered surface 113, which are formed along the circumferential direction. The inner circumferential surface 111 of the main ring 110 is an inwardly facing cylindrical surface extending parallel to the central axis C. The first side surface 112 of the main ring 110 is a plane perpendicular to the central axis C, extending outward from the end of the inner circumferential surface 111. The outer tapered surface 113 of the main ring 110 is an inclined surface facing outward, inclined with respect to the inner circumferential surface 111 and the first side surface 112, and formed with a gap between it and the inner circumferential surface 111 and the first side surface 112.

[0018] The backup ring 120 has an outer circumferential surface 121, a second side surface 122, and an inner tapered surface 123, all formed along the circumferential direction. The outer circumferential surface 121 of the backup ring 120 is an outward-facing cylindrical surface extending parallel to the central axis C. The second side surface 122 of the backup ring 120 is a plane perpendicular to the central axis C, extending inward from the end of the outer circumferential surface 121. The inner tapered surface 123 of the backup ring 120 is an inclined surface facing inward, inclined with respect to the outer circumferential surface 121 and the second side surface 122, and formed with a gap between it and the outer circumferential surface 121 and the second side surface 122.

[0019] In the seal ring 100, the outer tapered surface 113 of the main ring 110 and the inner tapered surface 123 of the backup ring 120 face each other. Also, in the seal ring 100, the angle α formed by the inner circumferential surface 111 of the main ring 110 and the outer tapered surface 113 is equal to the angle β formed by the outer circumferential surface 121 of the backup ring 120 and the inner tapered surface 123. Therefore, in the seal ring 100, the inner circumferential surface 111 of the main ring 110 and the outer circumferential surface 121 of the backup ring 120 face each other in the radial direction, and the first side surface 112 of the main ring 110 and the second side surface 122 of the backup ring 120 face each other in the direction of the central axis C.

[0020] Figure 3 shows the seal ring 100 assembled to the movable scroll 140 and housing 150 of the scroll compressor. The seal ring 100 is housed in a groove 141 provided in the movable scroll 140 and seals the gap between the movable scroll 140 and the housing 150 so that the fluid F on the outer circumference side of the groove 141 does not leak to the inner circumference side of the groove 141. Before being assembled to the movable scroll 140 and housing 150, the dimensions of the seal ring 100 in the direction of the central axis C (distance between the first side surface 112 and the second side surface 122) are slightly larger than the distance between the groove bottom of the groove 141 of the movable scroll 140 and the housing 150.

[0021] As shown in Figure 3, the seal ring 100 is assembled between the bottom of the groove 141 on the movable scroll 140 and the housing 150, with its inner circumferential surface 111 in contact with the inner wall surface of the groove 141 on the movable scroll 140. Therefore, in the state of the seal ring 100 shown in Figure 3, the first side surface 112 receives a pressing force from the housing 150, and the second side surface 122 receives a pressing force from the bottom of the groove 141 on the movable scroll 140. As a result, the main ring 110, which is softer than the backup ring 120, is compressed and deformed in the direction of the central axis C as it is sandwiched between the housing 150 and the inner tapered surface 123 of the backup ring 120.

[0022] Therefore, in the state of the seal ring 100 shown in Figure 3, the first side surface 112 is firmly in contact with the housing 150 due to the compressive force of the main ring 110. Furthermore, in the seal ring 100, the pressing force that the main ring 110 receives from the inner tapered surface 123 of the backup ring 120 on the outer tapered surface 113 has an inward circumferential component, so the inner circumferential surface 111 is firmly in contact with the inner wall surface of the groove 141 of the movable scroll 140. As a result, the seal ring 100 firmly seals the gap between the movable scroll 140 and the housing 150, thereby significantly reducing the amount of leakage to the inner circumferential side, even with low-viscosity fluids F such as gas.

[0023] In the seal ring 100, it is preferable that the dimension in the direction of the central axis C before assembly to the movable scroll 140 and housing 150 is 1.05 times or more and 1.20 times or less the distance between the groove bottom of the groove portion 141 provided in the movable scroll 140 and the housing 150. This allows the seal ring 100 to more effectively obtain the above-mentioned effect due to the compressive force of the main ring 110 while ensuring good assembly.

[0024] Furthermore, as shown in Figure 1, the main ring 110 is provided with a joint portion 130. The joint portion 130 has a first engaging portion 131 and a second engaging portion 132 that can move toward and away from each other. As a result, the main ring 110 can be assembled into the groove portion 141 of the movable scroll 140 in an overall enlarged diameter state by expanding the first engaging portion 131 and the second engaging portion 132 in the circumferential direction at the joint portion 130. In the main ring 110, the amount of fluid F leakage at the joint portion 130 can be reduced by devising the shapes of the first engaging portion 131 and the second engaging portion 132.

[0025] Figure 4 is a partial perspective view of the joint portion 130 of the main ring 110, viewed from the inner circumferential surface 111 side. Figure 5 is a cross-sectional view of the joint portion 130 along the line B-B' in Figure 4. The first engaging portion 131 has a first inclined surface 131a that slopes outward from the inner circumferential surface 111, similar to the outer tapered surface 113, and extends between the inner circumferential surface 111 and the first side surface 112 at a distance from the outer tapered surface 113. The second engaging portion 132 has a rod-like cross-section with a right-angled triangular shape, slopes outward from the inner circumferential surface 111, similar to the outer tapered surface 113, and has a second inclined surface 132a that faces the first inclined surface 131a of the first engaging portion 131.

[0026] In the state shown in Figure 3, the joint portion 130 of the main ring 110 is configured such that the area on the housing 150 side of the inner circumferential surface 111 that seals the gap between the movable scroll 140 and the housing 150 is formed by the second engaging portion 132, and there is no gap connecting the inner circumferential region and the outer circumferential region. Furthermore, in the state shown in Figure 3, the joint portion 130 also undergoes elastic deformation, causing the first inclined surface 131a of the first engaging portion 131 and the second inclined surface 132a of the second engaging portion 132 to be firmly in contact. For this reason, in the state shown in Figure 3, the amount of fluid F leakage at the joint portion 130 of the main ring 110 can be reduced.

[0027] The configuration of the seal ring 100 is not limited to the above and can be changed in various ways depending on the specifications of the movable scroll 140 and the housing 150. For example, in the seal ring 100, the configuration of the joint portion 130 of the main ring 110 can be changed in various ways depending on the allowable leakage amount of fluid F. Also, in the seal ring 100, the main ring 110 does not necessarily have to have a joint portion 130, and the backup ring 120 may have a joint portion.

[0028] [Second Embodiment] The seal ring 200 according to the second embodiment of the present invention is configured to seal the fluid F on the inner circumference. Figure 6 is a plan view of the seal ring 200. Figure 7 is a cross-sectional view of the seal ring 200 along the line C-C' in Figure 6. The seal ring 200 has a main ring 210 which is a second ring and a backup ring 220 which is a first ring. The main ring 210 and the backup ring 220 have a common central axis C and are superimposed on each other in the direction of the central axis C. The diameter of the backup ring 220 is slightly smaller than the diameter of the main ring 210.

[0029] The backup ring 220 is made of a harder resin than the main ring 210. Specifically, the main ring 210 is made of a first resin with a flexural modulus of less than 700 MPa. Examples of the first resin include polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), fluororubber (FKM), and hydrogenated nitrile rubber (HNBR). The backup ring 220 is made of a second resin with a flexural modulus of 700 MPa or more. The flexural modulus of the second resin is preferably 1000 MPa or more, and more preferably 1500 MPa or more. Examples of the second resin include polyetheretherketone (PEEK), polyphenylene sulfide (PPS), nylon 66, polyphenol (PF), polyethylene terephthalate (PBT), polyimide (PI), polyamideimide (PAI), polyacetal (POM), and polyphthalamide (PPA).

[0030] The main ring 210 has an outer circumferential surface 211, a first side surface 212, and an inner tapered surface 213, all formed along the circumferential direction. The outer circumferential surface 211 of the main ring 210 is an outward-facing cylindrical surface extending parallel to the central axis C. The first side surface 212 of the main ring 210 is a plane perpendicular to the central axis C, extending inward from the end of the outer circumferential surface 211. The inner tapered surface 213 of the main ring 210 is an inclined surface facing inward, inclined with respect to the outer circumferential surface 211 and the first side surface 212, and formed with a gap between it and the outer circumferential surface 211 and the first side surface 212.

[0031] The backup ring 220 has an inner circumferential surface 221, a second side surface 222, and an outer tapered surface 223, all formed along the circumferential direction. The inner circumferential surface 221 of the backup ring 220 is an inwardly facing cylindrical surface extending parallel to the central axis C. The second side surface 222 of the backup ring 220 is a plane perpendicular to the central axis C, extending outward from the end of the inner circumferential surface 221. The outer tapered surface 223 of the backup ring 220 is an inclined surface facing outward, inclined with respect to the inner circumferential surface 221 and the second side surface 222, and formed with a gap between it and the inner circumferential surface 221 and the second side surface 222.

[0032] In the seal ring 200, the inner tapered surface 213 of the main ring 210 and the outer tapered surface 223 of the backup ring 220 face each other. Also, in the seal ring 200, the angle α formed by the outer circumferential surface 211 of the main ring 210 and the inner tapered surface 213 is equal to the angle β formed by the inner circumferential surface 221 of the backup ring 220 and the outer tapered surface 223. Therefore, in the seal ring 200, the outer circumferential surface 211 of the main ring 210 and the inner circumferential surface 221 of the backup ring 220 face each other in the radial direction, and the first side surface 212 of the main ring 210 and the second side surface 222 of the backup ring 220 face each other in the direction of the central axis C.

[0033] Figure 8 shows the seal ring 200 assembled to the movable scroll 240 and housing 250 of the scroll compressor. The seal ring 200 is housed in a groove 241 provided in the movable scroll 240 and seals the gap between the movable scroll 240 and the housing 250 so that the fluid F on the inner circumference side of the groove 241 does not leak to the outer circumference side of the groove 241. Before being assembled to the movable scroll 240 and housing 250, the dimensions of the seal ring 200 in the direction of the central axis C (distance between the first side surface 212 and the second side surface 222) are slightly larger than the distance between the groove bottom of the groove 241 of the movable scroll 240 and the housing 250.

[0034] As shown in Figure 8, the seal ring 200 is assembled between the bottom of the groove 241 on the movable scroll 240 and the housing 250, with its outer peripheral surface 211 in contact with the inner wall surface of the groove 241 on the movable scroll 240. Therefore, in the state of the seal ring 200 shown in Figure 8, the first side surface 212 receives a pressing force from the housing 250, and the second side surface 222 receives a pressing force from the bottom of the groove 241 on the movable scroll 240. As a result, the main ring 210, which is softer than the backup ring 220, is compressed and deformed in the direction of the central axis C as it is sandwiched between the housing 250 and the outer tapered surface 223 of the backup ring 220.

[0035] Therefore, in the state of the seal ring 200 shown in Figure 8, the first side surface 212 is firmly in contact with the housing 250 due to the compressive force of the main ring 210. Furthermore, in the seal ring 200, the pressing force received by the main ring 210 from the outer tapered surface 223 of the backup ring 220 on the inner tapered surface 213 has an outer-circumferential component, so the outer surface 211 is firmly in contact with the outer wall surface of the groove 241 of the movable scroll 240. As a result, the seal ring 200 firmly seals the gap between the movable scroll 240 and the housing 250, significantly reducing leakage to the outer side even with low-viscosity fluids F such as gas.

[0036] In the seal ring 200, it is preferable that the dimension in the direction of the central axis C before assembly to the movable scroll 240 and housing 250 is 1.05 times or more and 1.20 times or less the distance between the groove bottom of the groove portion 241 provided in the movable scroll 240 and the housing 250. This allows the seal ring 200 to more effectively obtain the above-mentioned effect due to the compressive force of the main ring 210 while ensuring good assembly.

[0037] Furthermore, as shown in Figure 6, the main ring 210 is provided with a joint portion 230. The joint portion 230 has a first engaging portion 231 and a second engaging portion 232 that can move toward and away from each other. As a result, the main ring 210 can be assembled into the groove portion 241 of the movable scroll 240 in an overall enlarged diameter state by expanding the first engaging portion 231 and the second engaging portion 232 in the circumferential direction at the joint portion 230. In the main ring 210, the amount of fluid F leakage at the joint portion 230 can be reduced by devising the shapes of the first engaging portion 231 and the second engaging portion 232.

[0038] Figure 9 is a partial perspective view of the joint portion 230 of the main ring 210, viewed from the outer circumferential surface 211 side. Figure 10 is a cross-sectional view of the joint portion 230 along the line D-D' in Figure 9. The first engaging portion 231 is inclined inward from the outer circumferential surface 211, similar to the inner tapered surface 213, and has a first inclined surface 231a that extends between the outer circumferential surface 211 and the first side surface 212, spaced apart from the inner tapered surface 213. The second engaging portion 232 is rod-shaped with a right-angled triangular cross-section, is inclined inward from the outer circumferential surface 211, similar to the inner tapered surface 213, and has a second inclined surface 232a that faces the first inclined surface 231a of the first engaging portion 231.

[0039] In the state shown in Figure 8, the joint portion 230 of the main ring 210 is configured such that the area on the housing 250 side of the outer peripheral surface 211 that seals the gap between the movable scroll 240 and the housing 250 is formed by the second engaging portion 232, and there is no gap connecting the outer peripheral region and the inner peripheral region. Furthermore, in the state shown in Figure 8, the joint portion 230 also undergoes elastic deformation, causing the first inclined surface 231a of the first engaging portion 231 and the second inclined surface 232a of the second engaging portion 232 to be firmly in contact. For this reason, in the state shown in Figure 8, the amount of fluid F leakage at the joint portion 230 of the main ring 210 can be reduced.

[0040] The configuration of the seal ring 200 is not limited to the above and can be changed in various ways depending on the specifications of the movable scroll 240 and the housing 250. For example, in the seal ring 200, the configuration of the joint portion 230 of the main ring 210 can be changed in various ways depending on the allowable leakage amount of fluid F. Also, in the seal ring 200, the main ring 210 does not necessarily have a joint portion 230, and the backup ring 220 may have a joint portion.

[0041] [Third Embodiment] In the third embodiment of the present invention, a seal ring 200 having the same configuration as in the second embodiment is used to seal the gap between a shaft and a cylinder that reciprocate relatively. For this reason, the description of the configuration of the seal ring 200 is omitted in this embodiment.

[0042] Figure 11 shows the seal ring 200 assembled to the shaft 260 and cylinder 270. The seal ring 200 is fitted into a groove 261 provided around the entire circumference of the shaft 260, sealing the gap between the shaft 260 and the cylinder 270 so that fluid F on one side of the groove 261 in the direction of the central axis C does not leak to the other side. Before being assembled to the shaft 260 and cylinder 270, the dimension of the seal ring 200 in the direction of the central axis C (distance between the first side surface 212 and the second side surface 222) is slightly larger than the distance between the side walls of the groove 261 on the shaft 260.

[0043] As shown in FIG. 11, the seal ring 200 is assembled to the groove 261 of the shaft 260 with the first side surface 212 and the second side surface 222 abutting against both side wall surfaces of the groove 261 of the shaft 260, respectively. Therefore, in the seal ring 200 in the state shown in FIG. 11, the first side surface 212 receives a pressing force from one side wall surface of the groove 261 of the shaft 260, and the second side surface 222 receives a pressing force from the other side wall surface of the groove 261 of the shaft 260, so that the main ring 210, which is softer than the backup ring 220, is sandwiched between the side wall surface of the groove 261 of the shaft 260 and the outer tapered surface 223 of the backup ring 220 and is compressed and deformed in the direction of the central axis C.

[0044] Therefore, in the seal ring 200 in the state shown in FIG. 11, the first side surface 212 is firmly adhered to the side wall surface of the groove 261 of the shaft 260 by the compression force of the main ring 210. Further, in the seal ring 200, since the pressing force received by the main ring 210 from the outer tapered surface 223 of the backup ring 220 at the inner tapered surface 213 has a radially outward component, the outer peripheral surface 211 is firmly adhered to the cylinder 270. For this reason, in the seal ring 200, by firmly sealing the gap between the shaft 260 and the cylinder 270 with the first side surface 212, it is possible to significantly reduce the leakage amount even for a fluid F with low viscosity such as gas.

[0045] In the seal ring 200, it is preferable that the dimension in the direction of the central axis C before being assembled to the shaft 260 and the cylinder 270 is 1.05 times or more and 1.20 times or less the distance between both side wall surfaces of the groove 261 of the shaft 260. Thereby, in the seal ring 200, while ensuring good assemblability, the above-described action by the compression force of the main ring 210 can be obtained more effectively.

[0046] [Embodiment] Hereinafter, embodiments of the present invention will be described.

[0047] (Examples 1-1 and 1-2) In Examples 1-1 and 1-2, samples of the seal ring 100 according to the first embodiment were produced. In the sample according to Example 1-1, the dimension in the central axis C direction of the backup ring was adjusted so that it was 0.2 mm larger than the distance between the groove bottom of the groove portion of the movable scroll and the housing. In the sample according to Example 1-2, the dimension in the central axis C direction of the backup ring was adjusted so that it was 0.5 mm larger than the distance between the groove bottom of the groove portion of the movable scroll and the housing. Also, as a sample according to Comparative Example 1, a general seal ring with a rectangular cross-section was prepared.

[0048] For the samples according to Examples 1-1, 1-2 and Comparative Example 1, the leakage amount of the fluid F was measured by operating the scroll compressor assembled to the movable scroll and the housing. Nitrogen was used as the fluid F, and the air pressure was changed within the range of 0.1 to 0.7 MPa. Then, for the samples according to Examples 1-1, 1-2, the ratio (leakage amount reduction rate) at which the leakage amount was reduced with respect to the sample according to Comparative Example 1 at each air pressure was obtained. Fig. 12 is a graph showing the leakage amount reduction rate at each air pressure for the samples according to Examples 1-1, 1-2. In Fig. 12, the horizontal axis represents the air pressure (MPa), and the vertical axis represents the leakage amount reduction rate (%).

[0049] Referring to Fig. 12, it can be seen that for the samples according to Examples 1-1, 1-2, the leakage amount is significantly reduced compared to the sample according to Comparative Example 1. Specifically, for all the samples according to Examples 1-1, 1-2, the leakage amount reduction rate was 99% or more.

[0050] (Examples 2-1, 2-2) In Examples 2-1 and 2-2, samples of the seal ring 200 according to the second embodiment were prepared. In the sample according to Example 2-1, the dimension of the backup ring in the direction of the central axis C was adjusted so that the dimension in the direction of the central axis C was 0.2 mm larger than the distance between the groove bottom of the groove portion of the movable scroll and the housing. In the sample according to Example 2-2, the dimension of the backup ring in the direction of the central axis C was adjusted so that the dimension in the direction of the central axis C was 0.5 mm larger than the distance between the groove bottom of the groove portion of the movable scroll and the housing. In addition, a general seal ring with a rectangular cross-section was prepared as a sample according to Comparative Example 2.

[0051] For the samples in Examples 2-1, 2-2, and Comparative Example 2, the leakage rate of fluid F was measured by operating a scroll compressor assembled in a movable scroll and housing. Nitrogen was used as the fluid F, and the atmospheric pressure was varied within the range of 0.1 to 0.7 MPa. For the samples in Examples 2-1 and 2-2, the ratio of the reduction in leakage rate compared to the sample in Comparative Example 2 (leakage reduction rate) was determined at each atmospheric pressure. Figure 13 is a graph showing the leakage reduction rate at each atmospheric pressure for the samples in Examples 2-1 and 2-2. In Figure 13, the horizontal axis represents atmospheric pressure (MPa), and the vertical axis represents the leakage reduction rate (%).

[0052] Referring to Figure 13, it can be seen that the leakage amount in the samples of Examples 2-1 and 2-2 is significantly reduced compared to the sample of Comparative Example 2. Specifically, the leakage reduction rate was 80% or more in both the samples of Examples 2-1 and 2-2.

[0053] 100: Seal ring 110: Main ring 111: Inner circumferential surface 112: First side surface 113: Outer tapered surface 120: Backup ring 121: Outer circumferential surface 122: Second side surface 123: Inner tapered surface 130: Joint 200: Seal ring 210: Main ring 211: Outer circumferential surface 212: First side surface 213: Inner tapered surface 220: Backup ring 221: Inner circumferential surface 222: Second side surface 223: Outer tapered surface 230: Joint

Claims

1. A seal ring comprising: a first ring having an inner circumferential surface and an outer tapered surface inclined with respect to the inner circumferential surface; and a second ring having an outer circumferential surface and an inner tapered surface inclined with respect to the outer circumferential surface and facing the outer tapered surface, wherein one of the first ring and the second ring is formed of a first resin having a flexural modulus of less than 700 MPa, and the other is formed of a second resin having a flexural modulus of 700 MPa or more, wherein when the first ring is formed of the first resin, the seal ring seals the fluid on the outer circumferential surface side of the second ring, and when the second ring is formed of the first resin, the seal ring seals the fluid on the inner circumferential surface side of the first ring.

2. A seal ring according to claim 1, wherein the first ring is formed of the first resin, and the first ring further has a joint portion comprising: a first engaging portion having a first inclined surface that is inclined with respect to the inner circumferential surface in the same direction as the outer tapered surface and extends at a distance from the outer tapered surface; and a second engaging portion having a second inclined surface that faces the first inclined surface.

3. A seal ring according to claim 1, wherein the second ring is formed of the first resin, and the second ring further has a joint portion comprising: a first engaging portion having a first inclined surface that is inclined with respect to the outer circumferential surface in the same direction as the inner tapered surface and extends at a distance from the inner tapered surface; and a second engaging portion having a second inclined surface that faces the first inclined surface.

4. A seal ring according to any one of claims 1 to 3, wherein the fluid is a gas.

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