Seal device

Abstract

To suppress the deterioration of seal performance caused by an inclination of a seal axial line to a rotation axial line.SOLUTION: A seal device comprises an annular seal ring with a seal axial line as a center, and a seal holding ring for holding the seal ring. The seal holding ring has an annular holding groove which is recessed to the inside in a radial direction. The seal ring has a contact face which can contact with a low-pressure side groove side face in a face defining the holding groove in an axial line direction. The seal ring is divided into four or more pieces in a circumferential direction with respect to the seal axial line. A thrust load center radius is a distance in the radial direction between a thrust load center being an intermediate position between and an end of the contact face at the outside in the radial direction and a position at the most inside in the radial direction in the seal ring and the seal axial line. An inside end radius is a distance in the radial direction between an end at the most inside in the radial direction in the contact face and the seal axial line. A ratio of the inside end radius with respect to the thrust load center radius is equal to or lower than 1.20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a seal arrangement mounted about a shaft. [Background technology]

[0002] An example of a seal device that is attached around a shaft is the seal device described in Patent Document 1 below.

[0003] This seal device has a seal ring that faces the outer circumferential surface of the shaft and a seal retaining ring (seal ring receiver) that retains the seal ring. The seal ring is annular with the seal axis centered on the rotation axis of the shaft. The seal ring has an annular body and a plurality of annular seal fins that protrude radially inward with respect to the seal axis from the inner circumferential surface of the body.

[0004] In the technique described in Patent Document 1, a guide pin is provided to guide radial movement of the seal ring relative to its axis, thereby preventing the seal ring from becoming misaligned in the radial direction relative to its axis. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-097350 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the seal device described in Patent Document 1, the seal ring receives a thrust load from the high pressure side with respect to the seal ring as a reference, and a moment may be generated that tends to tilt the seal axis of the seal ring with respect to the rotation axis of the shaft. In this case, if the seal axis is tilted with respect to the rotation axis due to this moment, it may lead to deterioration of the sealing performance and damage to seal pieces such as seal fins.

[0007] Therefore, an object of the present disclosure is to provide a sealing device that can suppress deterioration of sealing performance and damage to seal pieces. [Means for solving the problem]

[0008] In order to achieve the above object, a sealing device according to one aspect of the present invention comprises: The seal ring is annular about a seal axis, and a seal retaining ring is annular about the seal axis and retains the seal ring from the outer circumferential side of the seal ring. The seal retaining ring has an annular retaining groove recessed toward the radially outer side, among the radially inner side and the radially outer side in the radial direction relative to the seal axis. The seal ring has a seal body having an annular shape about the seal axis and a portion inserted into the retaining groove of the seal retaining ring, and a plurality of seal pieces having an annular shape about the seal axis and disposed on the inner circumferential side of the seal body and fixed to the seal body. The seal body has an axial high pressure side and an axial low pressure side in the axial direction in which the seal axis extends, and a high pressure side surface facing the axial high pressure side and a low pressure side surface facing the axial low pressure side. The retaining groove is defined by a retaining groove bottom surface facing the radially inward, a high-pressure side retaining groove side surface facing the high-pressure side surface of the seal body in the axial direction, and a low-pressure side retaining groove side surface facing the low-pressure side surface of the seal body in the axial direction. At least a part of the low-pressure side surface of the seal body forms a contact surface of the seal ring that can contact the low-pressure side retaining groove side surface of the seal retaining ring in the axial direction. The seal ring is divided into four or more in the circumferential direction with respect to the seal axis. A ratio of an inner end radius to a thrust load center radius is 1.20 or less. The thrust load center radius is the radial distance between a thrust load center, which is a radially intermediate position between the radially outermost position of the portion where the seal ring contacts the seal retaining ring and the radially innermost position of the seal ring, and the seal axis. The inner end radius is the radial distance between the radially innermost end position of the contact surface and the seal axis.

[0009] The seal ring receives a thrust load from a high-pressure fluid present on the axial high-pressure side with respect to the seal ring. This thrust load may cause a moment to act on the seal ring, which tends to tilt the seal axis with respect to the rotation axis of the shaft. If the seal ring is divided into four or more parts in the circumferential direction, when such a moment acts on it, the seal axis may tilt with respect to the rotation axis of the shaft, which may lead to deterioration of sealing properties and damage to seal pieces such as seal fins. In this embodiment, the generation of a moment acting on the seal ring can be suppressed, and the seal axis of the seal ring can be suppressed from tilting with respect to the rotation axis of the shaft. Effect of the Invention

[0010] According to one aspect of the present disclosure, it is possible to suppress deterioration of sealing performance and damage to seal pieces caused by the seal axis of the seal ring being inclined relative to the rotational axis of the shaft. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a sealing device according to a first embodiment of the present disclosure. FIG. [Diagram 2] 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 4 is a cross-sectional view of a sealing device in a comparative example. [Figure 4] 13 is a graph showing the relationship between the division number of the seal ring and the upper limit ratio. [Diagram 5] FIG. 4 is a cross-sectional view of a sealing device in a second embodiment according to the present disclosure. [Figure 6] FIG. 11 is a cross-sectional view of a sealing device in a third embodiment according to the present disclosure. [Figure 7] FIG. 13 is a cross-sectional view of a sealing device according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Various embodiments of a sealing device according to the present disclosure and modified examples thereof will be described below with reference to the drawings.

[0013] "First embodiment" A first embodiment of a sealing device will be described with reference to Figs.

[0014] 1, the seal device S in this embodiment is a seal device provided around a shaft 1 that is rotatable about a rotation axis Ar. The seal device S includes a seal ring 10 that is annular about the seal axis As, and a seal retaining ring 20 that is annular about the seal axis As and retains the seal ring 10. The seal retaining ring 20 has a retaining groove 25 into which a portion of the seal ring 10 is inserted.

[0015] Here, the direction in which the seal axis As extends is referred to as the axial direction Da, the radial direction relative to the seal axis As is simply referred to as the radial direction Dr, and the circumferential direction relative to the seal axis As is simply referred to as the circumferential direction Dc. Moreover, of both sides of the axial direction Da, one side is referred to as the axial high pressure side Dah, and the other side is referred to as the axial low pressure side Dal. Furthermore, the side approaching the seal axis As in the radial direction Dr is referred to as the radial inner side Dri, and the side moving away from the seal axis As in the radial direction Dr is referred to as the radial outer side Dro. In this embodiment, when the seal device S is arranged around the shaft 1, the seal axis As of the seal device S is basically located on the aforementioned rotation axis Ar.

[0016] The sealing device S serves to prevent high-pressure fluid (e.g., steam) present on the axial high-pressure side Dah of the sealing device S from flowing out along the outer circumferential surface of the shaft 1 to the axial low-pressure side Dal of the sealing device S.

[0017] The seal ring 10 has a seal body 11 and multiple seal pieces 19. The seal body 11 is annular about the seal axis As. The multiple seal pieces 19 are annular about the seal axis As and arranged in the axial direction Da. The multiple seal pieces 19 are disposed on the inner periphery of the seal body 11 and fixed to the seal body 11. The radially inner ends Dri of the multiple seal pieces 19 face the outer periphery of the shaft 1 with a small gap therebetween.

[0018] The seal trunk 11 has a trunk main body 12 and a held portion 13 inserted into the holding groove 25. The trunk main body 12 has a trunk inner circumferential surface 12i facing the radially inward direction Dri, a trunk outer circumferential surface 12o facing the radially outward direction Dro, a trunk high-pressure side surface 12h facing the axial high-pressure side Dah, and a trunk low-pressure side surface 12l facing the axial low-pressure side Dal.

[0019] The held portion 13 has a held leg portion 14 protruding from the main body outer peripheral surface 12o to the radially outward side Dro, and a hook portion 15 provided at the end of the held leg portion 14 on the radially outward side Dro and protruding from the held leg portion 14 to the axial high pressure side Dah. The held leg portion 14 has a leg high pressure side 14h facing the axial high pressure side Dah and a leg low pressure side 14l facing the axial low pressure side Dal. The hook portion 15 has a hook outer peripheral surface 15o facing the radially outward side Dro, a hook inner peripheral surface 15i facing the radially inward side Dri, a hook high pressure side 15h facing the axial high pressure side Dah, and a hook low pressure side 15l facing the axial low pressure side Dal. The main body low pressure side 12l, the leg low pressure side 14l, and the hook low pressure side 15l are flush with each other. The main body low pressure side 12l, the leg low pressure side 14l, and the hook low pressure side 15l form the low pressure side 11l of the seal body 11. The hook outer peripheral surface 15o spreads from the radially outer end Dro of the hook low pressure side 15l toward the axial high pressure side DAh. The hook inner peripheral surface 15i spreads from the radially outer end of the leg high pressure side 14h toward the axial high pressure side Dah. The leg high pressure side 14h is located on the axial low pressure side Dal of the main body high pressure side 12h. The hook high pressure side 15h is located on the axial low pressure side Dal of the main body high pressure side 12h and on the axial high pressure side Dah of the leg high pressure side 14h. This hook high pressure side 15h connects the end of the axial high pressure side Dah of the hook outer peripheral surface 15o to the end of the axial high pressure side Dah of the hook inner peripheral surface 15i. The main body high pressure side 12 h , the leg high pressure side 14 h , and the hook high pressure side 15 h form the high pressure side 11 h of the seal body 11 .

[0020] The seal retainer ring 20 has a retainer ring barrel 22, a high pressure side wall portion 23, and a low pressure side wall portion 24. The retainer ring barrel 22 is cylindrical with the seal axis As at the center. The high pressure side wall portion 23 has a high pressure side first wall portion 23a and a high pressure side second wall portion 23b. The high pressure side first wall portion 23a is provided on the axial high pressure side Dah of the retainer ring barrel 22, and protrudes from the axial high pressure side Dah portion of the retainer ring barrel 22 to the radially inward Dri. The high pressure side second wall portion 23b is provided on the radially inward Dri of the high pressure side first wall portion 23a, and protrudes from the radially inward Dri portion of the high pressure side first wall portion 23a to the axial low pressure side Dal. The low pressure side wall portion 24 is provided on the axial low pressure side Dal of the retainer ring barrel 22, and protrudes from the axial low pressure side Dal portion of the retainer ring barrel 22 to the radially inward Dri. The retaining groove 25 is formed on the radially inner side Dri of the retaining ring barrel 22, between the high pressure side wall portion 23 and the low pressure side wall portion 24 in the axial direction Da.

[0021] The retaining groove 25 is an annular groove recessed radially outward Dro and centered on the seal axis As. The retaining groove 25 has a hook insertion groove portion 27 and a leg insertion groove portion .

[0022] The hook insertion groove 27 is a portion into which the hook portion 15 of the seal ring 10 is inserted. The width of the hook insertion groove 27 in the axial direction Da is wider than the width of the hook portion 15 in the axial direction Da. The hook insertion groove 27 is defined by a retaining groove bottom surface 25b, a radial movement restricting surface 27r, a high-pressure side retaining groove first side surface 27h, and a low-pressure side retaining groove first side surface 27l. The retaining groove bottom surface 25b is formed by a surface facing the radially inner side Dri of the retaining ring body 22. The retaining groove bottom surface 25b faces the hook outer peripheral surface 15o in the radial direction Dr. The radial movement restricting surface 27r is formed by a surface facing the radially outer side Dro of the high-pressure side second wall portion 23b. The radial movement restricting surface 27r faces the retaining groove bottom surface 25b in the radial direction Dr. Furthermore, this radial movement restricting surface 27r faces the hook inner peripheral surface 15i in the radial direction Dr. The high-pressure side retaining groove first side surface 27h is formed by a surface facing the axial low-pressure side Dal of the high-pressure side first wall portion 23a. This high-pressure side retaining groove first side surface 27h faces the hook high-pressure side surface 15h in the axial direction Da. The high-pressure side second wall portion 23b of the seal retaining ring 20 has a back-to-back relationship with the radial movement restricting surface 27r and has a high-pressure side inner peripheral surface 29r facing the radially inward Dri. This high-pressure side inner peripheral surface 29r faces the main body outer peripheral surface 12o of the seal body 11 in the radial direction Dr. The low-pressure side retaining groove first side surface 27l is formed by a surface facing the axial high-pressure side Dah of the low-pressure side wall portion 24. This low-pressure side retaining groove first side surface 27l faces the high-pressure side retaining groove first side surface 27h in the axial direction Da. Furthermore, this low-pressure-side retaining groove first side surface 27l faces the hook high-pressure side surface 15h in the axial direction Da.

[0023] The leg insertion groove 28 is a portion into which the held leg 14 of the seal ring 10 is inserted. The width of the leg insertion groove 28 in the axial direction Da is wider than the width of the held leg 14 in the axial direction Da and narrower than the width of the hook 15 in the axial direction Da. The leg insertion groove 28 is located on the radial inner side Dri of the hook insertion groove 27 and communicates with the hook insertion groove 27. The leg insertion groove 28 is defined by a high-pressure side holding groove second side surface 28h and a low-pressure side holding groove second side surface 28l. The high-pressure side holding groove second side surface 28h is formed by a surface facing the axial low-pressure side Dal of the high-pressure side second wall portion 23b. The high-pressure side holding groove second side surface 28h faces the leg high-pressure side surface 14h in the axial direction Da. The high pressure side retaining groove second side surface 28h and the high pressure side retaining groove first side surface 27h form the high pressure side retaining groove side surface 25h of the retaining groove 25. The low pressure side retaining groove second side surface 28l is formed by a surface facing the axial high pressure side Dah of the low pressure side wall portion 24. This low pressure side retaining groove second side surface 28l faces the high pressure side retaining groove second side surface 28h in the axial direction Da. Furthermore, this low pressure side retaining groove second side surface 28l faces the leg low pressure side surface 14l in the axial direction Da. In addition, this low pressure side retaining groove second side surface 28l is flush with the low pressure side retaining groove first side surface 27l. These low pressure side retaining groove second side surface 28l and low pressure side retaining groove first side surface 27l form the low pressure side retaining groove side surface 25l of the retaining groove 25.

[0024] A gap Ga exists between the high pressure side retaining groove first side surface 27h and the hook high pressure side surface 15h, which face each other in the axial direction Da. Also, a gap Gr exists between the high pressure side inner circumferential surface 29r and the main body outer circumferential surface 12o, which face each other in the radial direction Dr. In this way, because the gaps Ga and Gr exist between the seal ring 10 and the seal retaining ring 20, the seal ring 10 can tilt with respect to the seal retaining ring 20.

[0025] Of the low pressure side surface 11l of the seal ring 10, a portion on the radially outer side Dro forms a contact surface 11C that can come into contact with the low pressure side retaining groove side surface 25l of the retaining groove 25.

[0026] Here, the middle position in the radial direction Dr between the position P1o of the radially outermost Dro among the portions where the seal ring 10 contacts the seal retaining ring 20 and the position P1i of the radially innermost Dri in the seal ring 10 is defined as the thrust load center P1c. The position P1i of the radially innermost Dri in the seal ring 10 is the end of the radially innermost Dri of the seal piece 19. In addition, the position Pio of the radially outermost Dro among the portions where the seal ring 10 contacts the seal retaining ring 20 is the end of the radially outermost Dro of the contact surface 11C in this embodiment. The seal ring 10 receives a thrust load F directed toward the axial low pressure side Dal from the high pressure fluid present on the axial high pressure side Dah of the seal device S. The thrust load center P1c described above is the center in the radial direction Dr of the area where the seal ring 10 receives the thrust load F.

[0027] The radial distance Dr between the thrust load center P1c and the seal axis As is defined as the thrust load center radius R1. The radial distance Dr between the end position P2 of the radially innermost Dri of the contact surface 11C and the seal axis As is defined as the inner end radius R2.

[0028] In this embodiment, the ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 is 1.0 or less. In other words, R2 / R1≦1.

[0029] 2, in this embodiment, the seal ring 10 and the seal retainer ring 20 are both divided into a plurality of parts in the circumferential direction Dc. Specifically, the seal ring 10 is divided into four parts in the circumferential direction Dc, and the seal retainer ring 20 is divided into, for example, two parts in the circumferential direction Dc.

[0030] Next, in order to explain the effect of the sealing device S in this embodiment, a comparative example will be described with reference to FIG.

[0031] The seal device Sx in the comparative example also includes a seal ring 10 and a seal retainer ring 20x that retains the seal ring 10, similar to the seal device S in the present embodiment. The seal ring 10 in the comparative example is completely the same as the seal ring 10 in the present embodiment. The seal retainer ring 20x in the comparative example is basically the same as the seal retainer ring 20 in the present embodiment. Thus, the seal retainer ring 20x in the comparative example also includes a retainer ring body 22, a high-pressure side wall portion 23, and a low-pressure side wall portion 24x, similar to the seal retainer ring 20 in the present embodiment. The retainer groove 25x in the comparative example is also formed on the radial inner side Dri of the retainer ring body 22, between the high-pressure side wall portion 23 and the low-pressure side wall portion 24x in the axial direction Da. In this comparative example, a portion of the low-pressure side surface 11l of the seal ring 10 that can come into contact with the low-pressure side retainer groove side surface 25l of the retainer groove 25x forms a contact surface 11Cx. Also in this comparative example, since there are gaps Ga and Gr between the seal ring 10 and the seal retainer ring 20x, it is possible for the seal ring 10 to tilt with respect to the seal retainer ring 20x.

[0032] The low-pressure side wall portion 24x in the comparative example is also provided on the axial low-pressure side Dal of the retaining ring barrel 22, like the low-pressure side wall portion 24 in this embodiment, and protrudes from the axial low-pressure side Dal of the retaining ring barrel 22 to the radially inward Dri. However, the amount of protrusion of the low-pressure side wall portion 24x in the comparative example to the radially inward Dri is smaller than the amount of protrusion of the low-pressure side wall portion 24 in this embodiment to the radially inward Dri. Therefore, the position P2 of the end of the radially inward Dri of the contact surface 11Cx in the comparative example is located radially outward Dro than the position P2 of the end of the radially inward Dri of the contact surface 11C in this embodiment. As a result, the ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 in the comparative example is larger than the ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 in this embodiment. Specifically, the ratio (R2 / R1) in the comparative example is, for example, about 1.25.

[0033] The seal ring 10 in the comparative example is also divided into four in the circumferential direction Dc, similar to the seal ring 10 in this embodiment.

[0034] In the comparative example described above, when the seal ring 10 receives a thrust load F from the high-pressure fluid present on the axial high-pressure side Dah, a moment M acts about the position P2 of the end of the radially inner side Dri on the contact surface 11Cx to relatively displace the portion of the axial high-pressure side Dah of the seal axis As toward the radially outer side Dro with respect to the rotation axis Ar. Specifically, in the example shown in Fig. 3, a counterclockwise moment M acts about the position P2 of the end of the radially inner side Dri on the contact surface 11Cx on the portion above the seal axis As, and a counterclockwise moment M acts about the position P2 of the end of the radially inner side Dri on the contact surface 11Cx on the portion below the seal axis As.

[0035] If the seal ring 10 is not divided in the circumferential direction Dc, the counterclockwise moment M acting on the portion above the seal axis As is canceled out by the counterclockwise moment M acting on the portion below the seal axis As, so that the seal axis As does not tilt with respect to the rotation axis Ar.

[0036] However, as the number of divisions of the seal ring 10 in the circumferential direction Dc increases, the amount by which the moment M in a cross section including the seal axis As at a given position in the circumferential direction Dc is canceled by the moment M in a cross section including the seal axis As at another position in the circumferential direction Dc decreases. For this reason, as the number of divisions of the seal ring 10 in the circumferential direction Dc increases, the seal axis As may be inclined with respect to the rotation axis Ar, which may lead to deterioration of sealing performance and damage to the seal pieces 19.

[0037] When the ratio (R2 / R1) is approximately 1.25 and the seal ring 10 is divided into four in the circumferential direction Dc as in the comparative example, the thrust load F received from the high-pressure fluid causes the seal axis As to tilt with respect to the rotation axis Ar.

[0038] In this embodiment, like the comparative example, the seal ring 10 is divided into four in the circumferential direction Dc, but since the ratio (R2 / R1) is approximately 1.0 or less, even if the seal ring 10 receives a thrust load F from the high-pressure fluid, a moment M that tilts the seal axis As with respect to the rotation axis Ar does not act on each of the four divided portions of the seal ring 10. Therefore, in this embodiment, even if the seal ring 10 receives a thrust load F from the high-pressure fluid, the seal axis As of the seal ring 10 does not substantially tilt with respect to the rotation axis Ar, and deterioration of the sealing performance and damage to the seal piece 19 can be suppressed.

[0039] Second Embodiment A second embodiment of the sealing device will be described with reference to FIGS.

[0040] FIG. 4 is a graph showing the relationship between the number of divisions of the seal ring and the upper limit ratio (R2 / R1) at which the seal axis As does not substantially tilt with respect to the rotation axis Ar even when the seal ring receives a thrust load F from a high-pressure fluid.

[0041] As described above, as the number of divisions of the seal ring in the circumferential direction Dc increases, the amount by which the moment M in a cross section including the seal axis As at a given position in the circumferential direction Dc is canceled by the moment M in a cross section including the seal axis As at another position in the circumferential direction Dc decreases. Therefore, as shown in the graph in Figure 4, the upper limit ratio U(R2 / R1) decreases as the number of divisions increases. However, the upper limit ratio U(R2 / R1) will never be smaller than 1.0.

[0042] Specifically, when the seal ring is divided into four, the upper limit ratio U (R2 / R1) is 1.2. Therefore, when the seal ring is divided into four, by setting the ratio (R2 / R1) to 1.2 or less, the seal axis As does not substantially tilt with respect to the rotation axis Ar even if the seal ring receives a thrust load F from the high-pressure fluid. The seal ring 10 in the above-mentioned comparative example has a division number of 4 and a ratio (R2 / R1) of 1.25, so that when the seal ring 10 receives a thrust load F from the high-pressure fluid, the seal axis As tilts with respect to the rotation axis Ar.

[0043] When the seal ring is divided into 6 parts, the upper limit ratio U (R2 / R1) is 1.1. Therefore, when the seal ring is divided into 6 parts, by setting the ratio (R2 / R1) to 1.1 or less, the seal axis As will not substantially tilt with respect to the rotation axis Ar even if the seal ring receives a thrust load F from the high-pressure fluid.

[0044] When the seal ring is divided into 8 parts, the upper limit ratio U (R2 / R1) is 1.06. Therefore, when the seal ring is divided into 8 parts, by setting the ratio (R2 / R1) to 1.06 or less, the seal axis As will not substantially tilt with respect to the rotation axis Ar even if the seal ring receives a thrust load F from the high-pressure fluid.

[0045] The sealing device in this embodiment is a sealing device based on the above viewpoint. As shown in FIG. 5, the sealing device Sa in this embodiment also includes a seal ring 10 and a seal retaining ring 20a that retains the seal ring 10, similar to the sealing device S in the first embodiment. The seal ring 10 in this embodiment has four divisions, similar to the seal ring 10 in the first embodiment. The seal retaining ring 20a in this embodiment also has a retaining ring body 22, a high-pressure side wall portion 23, and a low-pressure side wall portion 24a, similar to the seal retaining ring 20 in this embodiment. However, the protruding amount of the low-pressure side wall portion 24b in this embodiment toward the radially inward Dri from the retaining ring body 22 is greater than the protruding amount of the low-pressure side wall portion 24x in the comparative example described above toward the radially inward Dri from the retaining ring body 22, but is smaller than the protruding amount of the low-pressure side wall portion 24 in the first embodiment toward the radially inward Dri from the retaining ring body 22. In this relationship, the ratio (R2 / R1) of the seal device Sa in this embodiment is larger than the ratio (R2 / R1) in the first embodiment, and is 1.05.

[0046] Although the ratio (R2 / R1) of the sealing device Sa in this embodiment is 1.05, which is larger than the ratio (R2 / R1) of the sealing device S in the first embodiment, it is equal to or less than the upper limit ratio U (R2 / R1=1.2) when the division number is 4. Therefore, also in this embodiment, even if a thrust load F is applied from the high-pressure fluid, the seal axis As of the seal ring 10 does not substantially tilt with respect to the rotation axis Ar, and deterioration of the sealing performance and damage to the seal piece 19 can be suppressed.

[0047] In the sealing device Sa of this embodiment, the seal ring 10 is divided into four parts. However, if the seal ring 10 is divided into six parts, the ratio (R2 / R1) can be set to be equal to or less than the upper limit ratio U (R2 / R1 = 1.1), and if the seal ring 10 is divided into eight parts, the ratio (R2 / R1) can be set to be equal to or less than the upper limit ratio U (R2 / R1 = 1.06).

[0048] "Third embodiment" A third embodiment of the sealing device will be described with reference to FIG.

[0049] As shown in FIG. 6, like the seal device S in the first embodiment, the seal device Sb in this embodiment also includes a seal ring 10b and a seal retaining ring 20b that retains the seal ring 10b.

[0050] The seal ring 10b in this embodiment also has a seal body 11b and a plurality of seal pieces 19, similar to the seal ring 10 in the first embodiment. The seal body 11b is annular about the seal axis As. The plurality of seal pieces 19 are annular about the seal axis As and arranged in the axial direction Da. The plurality of seal pieces 19 are arranged on the inner circumferential side of the seal body 11b and fixed to the seal body 11b. As described above, the seal body 11b in this embodiment has a body inner circumferential surface 12i from which the plurality of seal pieces 19 protrude radially inward Dri. This seal body 11b further has a protruding portion 16 protruding radially inward Dri from a portion of the axial low pressure side Dal of the body inner circumferential surface 12i. The surface of this protruding portion 16 facing the axial low pressure side Dal is a part of the low pressure side surface 11l of the seal body 11b. Similarly to the seal ring 10 in the first embodiment, the seal ring 10b in this embodiment is also divided into four in the circumferential direction Dc.

[0051] The seal retaining ring 20b in this embodiment also has a retaining ring body 22, a high pressure side wall portion 23, and a low pressure side wall portion 24b, similar to the seal retaining ring 20 in the first embodiment. The retaining groove 25 in this embodiment is also formed on the radial inner side Dri of the retaining ring body 22, between the high pressure side wall portion 23 and the low pressure side wall portion 24b in the axial direction Da. The protrusion amount of the low pressure side wall portion 24b from the retaining ring body 22 to the radial inner Dri in this embodiment is greater than the protrusion amount of the low pressure side wall portion 24 from the retaining ring body 22 to the radial inner Dri in the first embodiment. Therefore, the end of the radial inner Dri of the low pressure side retaining groove side surface 25l in this embodiment is located radially inner Dri than the end of the radial inner Dri of the low pressure side retaining groove side surface 25l in the first embodiment. This low pressure side retaining groove side surface 25l is in contact with the low pressure side surface 11l of the seal body 11b. Therefore, also in this embodiment, at least a portion of the low-pressure side surface 11l of the seal body 11b forms the contact surface 11Cb of the seal ring 10b.

[0052] The position P2 of the end of the radially inner Dri of the contact surface 11Cb in this embodiment is located radially inward Dri of the body inner circumferential surface 12i of the seal body 11b, and radially inward Dri of the position P2 of the end of the radially inner Dri of the contact surface 11C in the first embodiment. Therefore, the inner end radius R2, which is the radial distance Dr between the end of the radially innermost Dri of this contact surface 11Cb and the seal axis As, is smaller than the inner end radius R2 in the first embodiment.

[0053] As described above, the inner end radius R2 in this embodiment is smaller than the inner end radius R2 in the first embodiment, so that the ratio (R2 / R1) in this embodiment is smaller than the ratio (R2 / R1) in the first embodiment. Thus, like the ratio (R2 / R1) in the first embodiment, the ratio (R2 / R1) in this embodiment is also 1.0 or less. Therefore, even if a thrust load F is applied from a high-pressure fluid, in this embodiment as well, the seal axis As of the seal ring 10b is not substantially inclined with respect to the rotation axis Ar, and deterioration of the sealing performance and damage to the seal piece 19 can be suppressed.

[0054] As described above, the upper limit ratio U(R2 / R1) gradually decreases as the number of divisions of the seal ring increases. Therefore, when the number of divisions of the seal ring is 6 or more, it is effective to provide the protrusion 16 on the seal body 11b of the seal ring 10b to reduce the inner end radius R2, as in this embodiment.

[0055] "Fourth embodiment" A fourth embodiment of the sealing device will be described with reference to FIG.

[0056] As shown in FIG. 7, the seal device Sc in this embodiment also includes a seal ring 10 and a seal retaining ring 20c that retains the seal ring 10, similar to the seal device S in the first embodiment.

[0057] The seal ring 10 in this embodiment is the same as the seal ring 10 in the first embodiment.

[0058] The seal retainer ring 20c in this embodiment has a retainer ring body 21 and a spacer 30. The retainer ring body 21 has a retainer ring barrel 22, a high pressure side wall portion 23, and a low pressure side wall portion 24c, similar to the seal retainer ring 20 in the first embodiment. A ring-shaped groove 26 is formed on the radial inner side Dri of the retainer ring barrel 22 between the high pressure side wall portion 23 and the low pressure side wall portion 24c in the axial direction Da, recessed toward the radial outer side Dro, and centered on the seal axis As. This groove 26 is defined by a retainer groove bottom surface 25b facing the radial inner side Dri, a high pressure side retainer groove side surface 25h facing the high pressure side surface 11h of the seal barrel 11 in the axial direction Da, and a low pressure side groove side surface 26l facing the low pressure side surface 11l of the seal barrel 11 in the axial direction Da. The retainer groove bottom surface 25b is formed by a surface facing the radial inner side Dri of the retainer ring barrel 22. The high pressure side retaining groove side surface 25h is formed by a surface facing the axial low pressure side Dal of the high pressure side wall portion 23. The low pressure side groove side surface 26l is formed by a surface facing the axial high pressure side Dah of the low pressure side wall portion 24c.

[0059] The spacer 30 has a ring disk portion 31 having a ring disk shape centered on the seal axis As, and a cylindrical portion 32 having a cylindrical shape centered on the seal axis As. The cylindrical portion 32 extends from a radially outer portion Dro of the ring disk portion 31 toward the axial high pressure side Dah. The inner peripheral surface of the cylindrical portion 32 faces or contacts the hook outer peripheral surface 15o of the seal body 11. The ring disk portion 31 has a disk first side surface 31a facing the axial high pressure side Dah and a disk second side surface 31b facing the axial low pressure side Dal. This ring disk portion 31 is located between the low pressure side surface 11l of the seal body 11 and the low pressure groove side surface 26l of the groove 26. The disk first side surface 31a of the ring disk portion 31 contacts the low pressure side surface 11l of the seal body 11. The second disk side surface 31b of the ring disk portion 31 contacts the low-pressure side groove side surface 26l of the groove 26. The end of the radially inner Dri of the ring disk portion 31 protrudes radially inward Dri further than the end of the radially inner Dri of the low-pressure side wall portion 24c of the retaining ring body 21.

[0060] The retaining groove 25c in this embodiment is formed by the groove 26 of the retaining ring body 21 and the spacer 30. This retaining groove 25c is defined by a surface having the retaining groove bottom surface 25b of the groove 26, the high-pressure side retaining groove side surface 25h of the groove 26, a part of the low-pressure side groove side surface 26l of the groove 26, and the disk first side surface 31a of the spacer 30. The low-pressure side retaining groove side surface 25lc of this retaining groove 25c has a part of the low-pressure side groove side surface 26l of the groove 26 and the disk first side surface 31a of the spacer 30.

[0061] The contact surface 11Cc of the surface of the seal ring 10 that can contact the seal retainer ring 20c in the axial direction Da is a portion of the low-pressure side surface 11l of the seal body 11 that can contact the disk first side surface 31a of the spacer 30, which is a part of the low-pressure side retainer groove side surface 25lc of the retainer groove 25c. In this embodiment, the position P2 of the end of the radially innermost Dri of the contact surface 11Cc is the end of the radially inner Dri of the disk first side surface 31a of the spacer 30. Therefore, the inner end radius R2 in this embodiment is the radial distance Dr between the end of the radially inner Dri of the disk first side surface 31a of the spacer 30 and the seal axis As. In this embodiment, the ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 is 1.0 or less, as in the first embodiment. Therefore, even in this embodiment, even if a thrust load F is applied from a high-pressure fluid, the seal axis As of the seal ring 10 does not substantially tilt with respect to the rotation axis Ar, and deterioration of the sealing performance and damage to the seal piece 19 can be suppressed.

[0062] In this embodiment, the position P2 of the end of the radially inner Dri of the contact surface 11Cc is located radially inward Dri than the end of the radially inner Dri of the low-pressure side wall portion 24c of the retaining ring body 21. For this reason, if, for some reason, the end of the radially inner Dri of the low-pressure side wall portion 24c is located radially outward Dro than the end of the radially inner Dri of the low-pressure side wall portion 24, 24a in the first or second embodiment and the ratio (R2 / R1) cannot be made equal to or less than the upper limit ratio U(R2 / R1), it is effective to provide a spacer 30 as in this embodiment.

[0063] "Variations" The seal devices S, Sa, Sb, and Sc in the above embodiments are fin seal devices or labyrinth seal devices having a plurality of fins as the plurality of seal pieces 19. However, the seal device may be a brush seal device having a plurality of wires as the plurality of seal pieces, or a leaf seal device having a plurality of thin plates as the plurality of seal pieces, or the like.

[0064] Furthermore, the present disclosure is not limited to the embodiments described above. Various additions, modifications, substitutions, partial deletions, etc. are possible within the scope of the conceptual idea and intent of the present invention derived from the contents defined in the claims and their equivalents.

[0065] "Additional Notes" The sealing devices S, Sa, Sb, and Sc in the above-described embodiments and modified examples can be understood, for example, as follows. (1) A sealing device according to a first aspect, The seal retaining ring 20 includes an annular seal ring 10, 10b centered on the seal axis As, and a seal retaining ring 20, 20a, 20b, 20c that is annular about the seal axis As and holds the seal ring 10, 10b from the outer circumferential side of the seal ring 10, 10b. The seal retaining ring 20, 20a, 20b, 20c has an annular retaining groove 25, 25c recessed toward the radially outer side Dro out of the radially inner side Dri and the radially outer side Dro in the radial direction Dr relative to the seal axis As. The seal ring 10, 10b has a seal body 11, 11b that is annular about the seal axis As and has a portion inserted into the retaining groove 25, 25c of the seal retaining ring 20, 20a, 20b, 20c, and a plurality of seal pieces 19 that are annular about the seal axis As and are disposed on the inner peripheral side of the seal body 11, 11b and fixed to the seal body 11, 11b. The seal body 11, 11b has an axial high pressure side Dah and an axial low pressure side Dal in the axial direction Da in which the seal axis As extends, and has a high pressure side 11h facing the axial high pressure side Dah and a low pressure side 11l facing the axial low pressure side Dal. The retaining groove 25, 25c is defined by a retaining groove bottom surface 25b facing the radially inward Dri, a high-pressure side retaining groove side surface 25h facing the high-pressure side surface 11h of the seal body 11, 11b in the axial direction Da, and a low-pressure side retaining groove side surface 25l, 25lc facing the low-pressure side surface 11l of the seal body 11, 11b in the axial direction Da. At least a part of the low-pressure side surface 11l of the seal body 11, 11b forms a contact surface 11C, 11Cb, 11Cc of the seal ring 10, 10b that can contact the low-pressure side retaining groove side surface 25l, 25lc of the seal retaining ring 20, 20a, 20b, 20c in the axial direction Da. The seal ring 10, 10b is divided into four or more parts in the circumferential direction Dc relative to the seal axis As. The ratio of the inner end radius R2 to the thrust load center radius R1 (R2 / R1) is 1.20 or less.The thrust load center radius R1 is the distance in the radial direction Dr between a thrust load center P1c, which is an intermediate position in the radial direction Dr between a position P1o of the radially outermost Dro of the portion of the seal ring 10, 10b in contact with the seal retaining ring 20, 20a, 20b, 20c and a position P1i of the radially innermost Dri of the seal ring 10, 10b, and the seal axis As. The inner end radius R2 is the distance in the radial direction Dr between a position P2 of the end of the radially innermost Dri of the contact surface 11C, 11Cb, 11Cc and the seal axis As.

[0066] The seal rings 10, 10b receive a thrust load F from the high-pressure fluid present on the axial high-pressure side Dah with respect to the seal rings 10, 10b. This thrust load F may cause a moment M to act on the seal rings 10, 10b, which tends to tilt the seal axis As with respect to the rotation axis Ar of the shaft 1. If the seal rings 10, 10b are divided into four or more parts in the circumferential direction Dc, when such a moment M acts on them, the seal axis As may tilt with respect to the rotation axis Ar of the shaft 1, which may lead to deterioration of sealing properties and damage to the seal pieces 19 such as seal fins. In this embodiment, the generation of the moment M acting on the seal rings 10, 10b can be suppressed, and the seal axis As of the seal rings 10, 10b can be suppressed from tilting with respect to the rotation axis Ar of the shaft 1.

[0067] (2) The sealing device in the second aspect is In the seal device according to the first aspect, the seal ring 10 is divided into six in the circumferential direction Dc. A ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 is 1.10 or less.

[0068] In this embodiment, even if the seal ring 10 is divided into six in the circumferential direction Dc, the generation of moment M acting on the seal ring 10 can be suppressed, and the seal axis As can be prevented from tilting relative to the rotation axis Ar of the shaft 1.

[0069] (3) The sealing device in the third aspect comprises: In the seal device according to the first aspect, the seal ring 10 is divided into eight parts in the circumferential direction Dc. A ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 is 1.06 or less.

[0070] In this embodiment, even if the seal ring 10 is divided into eight parts in the circumferential direction Dc, the generation of moment M acting on the seal ring 10 can be suppressed, and the seal axis As can be prevented from tilting relative to the rotation axis Ar of the shaft 1.

[0071] (4) In a fourth aspect, the sealing device comprises: In the seal device of the first aspect, a ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 is 1.0 or less.

[0072] In this embodiment, regardless of the number of divisions of the seal ring 10, the generation of moment M acting on the seal ring 10 can be suppressed, and the inclination of the seal axis As with respect to the rotation axis Ar of the shaft 1 can be suppressed.

[0073] (5) In a fifth aspect, the sealing device comprises: In the seal device according to any one of the first to fourth embodiments, the seal body 11b has a body inner circumferential surface 12i facing the inner circumferential side, from which the plurality of seal pieces 19 protrude toward the radially inward Dri, and a protruding portion 16 protruding from the axial low pressure side Dal of the body inner circumferential surface 12i toward the radially inward Dri. At least a part of the surface of the protruding portion 16 facing the axial low pressure side Dal forms a part of the contact surface 11Cb.

[0074] In this embodiment, by providing the protrusion 16 on the seal body 11b, the end of the contact surface 11Cb that is the innermost in the radial direction Dri can be easily brought close to the seal axis As. Therefore, in this embodiment, the inner end radius R2 can be easily reduced, and the ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 can also be easily reduced.

[0075] (6) A sealing device according to a sixth aspect, In the seal device according to any one of the first to fourth aspects, the seal retaining ring 20c has a retaining ring body 21 having an annular groove 26 that is recessed toward the radially outer side Dro and a spacer 30 that is partially inserted into the groove 26. The spacer 30 and the groove 26 form the retaining groove 25c. The spacer 30 contacts at least a part of the low-pressure groove side surface 26l that faces the axial high-pressure side Dah among the surfaces that define the groove 26, and contacts at least a part of the low-pressure side surface 11l of the seal body 11. The end of the radially innermost Dri of the contact surface 11Cc is the end of the radially innermost Dri among the surfaces where the low-pressure side surface 11l of the seal body 11 contacts the spacer 30.

[0076] In this embodiment, the end of the contact surface 11Cc that is the radially innermost Dri can be easily brought closer to the seal axis As by providing the spacer 30. Therefore, in this embodiment, the inner end radius R2 can be easily reduced, and the ratio (R2 / R1) of the inner end radius R2 to the thrust load center radius R1 can also be easily reduced.

[0077] (7) A sealing device according to a seventh aspect, In the sealing device according to any one of the first to sixth aspects, the seal body 11, 11b has a body main body 12 and a held portion 13 inserted into the holding groove 25, 25c. The body main body 12 has a body inner peripheral surface 12i facing the radially inward Dri, from which the seal pieces 19 protrude toward the radially inward Dri, and a body outer peripheral surface 12o facing the radially outward Dro. The held portion 13 has a held leg portion 14 protruding from the body outer peripheral surface 12o of the body main body 12 to the radially outward Dro, and a hook portion 15 provided at an end of the radially outward Dro of the held leg portion 14 and protruding from the held leg portion 14 to the axial high pressure side Dah. The holding groove 25, 25c has a leg insertion groove portion 28 and a hook insertion groove portion 27. The leg insertion groove 28 is insertable with the held leg 14, and the width of the leg insertion groove 28 in the axial direction Da is wider than the width of the held leg 14 in the axial direction Da and narrower than the width of the hook portion 15 in the axial direction Da. The hook insertion groove 27 is located on the radial outside Dro of the leg insertion groove 28 and communicates with the leg insertion groove 28, is insertable with the hook portion 15, and the width of the hook insertion groove 27 in the axial direction Da is wider than the width of the hook portion 15 in the axial direction Da. [Explanation of symbols]

[0078] 1: Axis S, Sa, Sb, Sc, Sx: Sealing device 10, 10b: Seal ring 11, 11b: Seal body 11h: High pressure side 11l: Low pressure side 11C,11Cb,11Cc,11Cx: Contact surface 12: Body 12i: Inner circumferential surface of the barrel 12o: Outer surface of main body 12h: High pressure side of the main body 12l: Low pressure side of main body 13:Holded part 14: Retained leg 14h: High pressure side of legs 14L:Leg low pressure side 15: Hook section 15i: Inner surface of hook 15o: Hook outer surface 15h: Hook high pressure side 15L: Hook low pressure side 16:Protrusion 19: Sticker piece 20, 20a, 20b, 20c, 20x: Seal retaining ring 21:Retaining ring body 22: Holding ring barrel 23: High pressure side wall 23a: High pressure side first wall 23b: High pressure side second wall 24, 24a, 24b, 24c, 24x: low pressure side wall 25,25c,25x: Retaining groove 26: Groove 25h: High pressure side retaining groove side 25l: Low pressure side retaining groove side 25b: Bottom of retaining groove 26l: Low pressure gutter side 27: Hook insertion groove 27h: First side of high pressure side retaining groove 27l: First side of low pressure side retaining groove 27r: Radial movement restriction surface 28: Leg insertion groove 28h: High pressure side retaining groove second side 28l: Low pressure side retaining groove second side 29r: High pressure side inner surface 30: Spacer 31: Ring disc section 31a: First side of disk 31b: Second side of the disk 32: Cylinder part Ga,Gr: Gap F: Thrust load M: Moment P1i: Position of the radially inner end of the seal ring P1o: Position of the radially outer end of the contact surface P1c: Thrust load center P2: Position of the radially inner end of the contact surface R1: Thrust load center radius R2: Inner edge radius Ar: axis of rotation As: Seal axis Da: Axial direction Dah: Axial high pressure side Dal: Axial low pressure side Dc: Circumferential direction Dr: Radial direction Dri: Radial inner direction Dro: Radial outer side

Claims

1. A seal ring with an annular shape centered on the seal axis, A seal retaining ring that forms an annular shape with respect to the seal axis and holds the seal ring from the outer circumference side of the seal ring, Equipped with, The seal retaining ring has an annular retaining groove that is recessed toward the radially outer side of the radial direction relative to the seal axis, The seal ring comprises a seal body that is annular around the seal axis and partially inserted into the retaining groove of the seal retaining ring, and a plurality of seal pieces that are annular around the seal axis, arranged on the inner circumference of the seal body and fixed to the seal body. The seal body comprises a body, a retained portion inserted into the retaining groove, and, in the axial direction in which the seal axis extends, a high-pressure side facing the high-pressure side and a low-pressure side facing the low-pressure side. The body of the aforementioned shell has an inner circumferential surface facing radially inward, on which the plurality of sealing pieces protrude radially inward, and an outer circumferential surface facing radially outward, The holding portion has a holding leg portion that protrudes radially outward from the outer circumferential surface of the main body of the main body, and a hook portion provided radially outward from the holding leg portion and protruding from the holding leg portion toward the axial high-voltage side. The retaining groove is defined by the bottom surface of the retaining groove facing radially inward, the high-pressure side retaining groove surface facing the high-pressure side of the seal cylinder in the axial direction, and the low-pressure side retaining groove surface facing the low-pressure side of the seal cylinder in the axial direction. At least a portion of the low-pressure side surface of the seal body forms a contact surface of the seal ring that can contact the low-pressure side retaining groove surface of the seal retaining ring in the axial direction, The seal ring is divided into four or more sections in the circumferential direction with respect to the seal axis. The ratio of the inner end radius to the thrust load center radius is 1.20 or less. The thrust load center radius is the radial distance between the thrust load center, which is an intermediate position in the radial direction between the radially outermost position of the portion of the seal ring that is in contact with the seal retaining ring and the radially innermost position of the seal ring, and the seal axis. The inner end radius is the radial distance between the position of the radially innermost end of the contact surface and the seal axis. Sealing device.

2. In the sealing device according to claim 1, The seal ring is divided into six sections in the circumferential direction. The ratio of the inner end radius to the center radius of the thrust load is 1.10 or less. Sealing device.

3. In the sealing device according to claim 1, The seal ring is divided into eight sections in the circumferential direction, The ratio of the inner end radius to the center radius of the thrust load is 1.06 or less. Sealing device.

4. In the sealing device according to claim 1, The ratio of the inner end radius to the thrust load center radius is 1.0 or less. Sealing device.

5. In the sealing device according to any one of claims 1 to 4, The seal body has an inner circumferential surface facing the inner circumference, on which the plurality of seal pieces protrude radially inward, and a projection that protrudes radially inward from the low-pressure side of the axis of the inner circumferential surface of the body. At least a portion of the surface of the protruding portion facing the low-pressure side of the axis forms a portion of the contact surface. Sealing device.

6. In the sealing device according to any one of claims 1 to 4, The seal retaining ring comprises a retaining ring body that is annular in shape with respect to the seal axis and has an annular groove that is recessed radially outward, and a spacer that fits into the groove in part. The retaining groove is formed by the spacer and the groove. The spacer contacts at least a portion of the low-pressure side groove surface facing the high-pressure side of the axis, among the surfaces defining the groove, and also contacts at least a portion of the low-pressure side of the seal body. The radially innermost end of the contact surface is the radially innermost end of the surface on which the low-pressure side of the seal body contacts the spacer. Sealing device.

7. In the sealing device according to any one of claims 1 to 4, The retaining groove has a leg insertion groove and a hook insertion groove, The leg insertion groove is such that the leg to be held can be inserted into it, and the axial width of the leg insertion groove is wider than the axial width of the leg to be held and narrower than the axial width of the hook portion. The hook insertion groove is located radially outward from the leg insertion groove, communicates with the leg insertion groove, allows the hook to be inserted, and the axial width of the hook insertion groove is wider than the axial width of the hook. Sealing device.

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