Sealing ring

Abstract

Provided is a sealing ring capable of maintaining a degree of parallelism between sliding surfaces.　A sealing ring 3 includes a sliding surface 3a which rotates and slides relative to a shaft 1 or a housing 2 through which the shaft 1 is inserted, and an installation surface 3b which intersects the sliding surface 3a and is installed on the other of the shaft 1 and the housing 2, the sealing ring serving as a partition between one space H located on the opposite side to a side of the sliding surface 3a intersecting the installation surface 3b, and another space L installed on the intersection side, and the seal ring serving as a partition between the one space H disposed on the opposite side to the installation surface 3b and the other space L disposed on the installation surface 3b side, wherein a dynamic pressure generating mechanism 36 which communicates with the one space H and includes a dynamic pressure generating portion 39b, and a fluid recovery mechanism 37 which is disposed closer to the one space H side than the dynamic pressure generating portion 39b and which communicates with the relative rotation upstream side of the dynamic pressure generation mechanism 36 are provided on the sliding surface 3a.

Description

Seal ring

[0001] The present invention relates to a seal ring used to seal a gap between a shaft and a housing, and more particularly to a seal ring used by being mounted in an annular groove, known as a stuffing box.

[0002] For example, an annular seal ring is placed between the rotating shaft and housing of a rotary machine as a shaft seal device to prevent leakage of a sealed fluid. In recent years, there has been a demand for reducing the energy lost due to sliding of such seal rings, for environmental reasons.

[0003] For example, the seal ring shown in Patent Document 1 is fixed to a housing and is loosely fitted rotatably into an annular groove provided in a rotating shaft, so that the side of the seal ring and the side of the annular groove can slide relative to each other.

[0004] The side of the seal ring is provided with an oil groove that communicates with the oil chamber and a wedge-effect groove that extends circumferentially from the oil groove. When the rotating shaft rotates, hydraulic oil is drawn in from the oil chamber through the oil groove, and a wedge effect in the wedge-effect groove generates dynamic pressure, lifting the side of the seal ring above the side of the annular groove and forming an oil film. This reduces the friction between the side of the seal ring and the side of the annular groove.

[0005] Japanese Patent Application Laid-Open No. 9-210211 (page 4, Figure 4)

[0006] In the seal ring of Patent Document 1, the seal ring is disposed so as to protrude radially outward from the annular groove of the rotating shaft, and dynamic pressure due to the wedge effect-generating groove is not generated in the outer diameter portion of the side surface of the seal ring. However, because dynamic pressure is generated only in the inner diameter portion of the side surface of the seal ring, there is a risk that the seal ring will twist so that the inner diameter portion moves away from the side surface of the annular groove and the outer diameter portion moves closer to the side surface of the annular groove, reducing the dynamic pressure generation effect.

[0007] The present invention has been made in view of these problems, and has as its object to provide a seal ring capable of maintaining parallelism between the sliding surfaces.

[0008] To solve the above problems, the seal ring of the present invention has a sliding surface that rotates and slides relative to a shaft or a housing through which the shaft is inserted, and an installation surface that intersects with the sliding surface and is installed on the other of the shaft and the housing, and separates one space located on the sliding surface opposite the side where the installation surface intersects with the installation surface from another space located on the intersecting side, and the sliding surface is provided with a dynamic pressure generating mechanism having a dynamic pressure generating unit that communicates with the one space, and a fluid recovery mechanism that is located on the one space side of the dynamic pressure generating unit and communicates with the upstream side of the dynamic pressure generating mechanism in terms of relative rotation. With this, the pressure on the one space side of the positive pressure generated near the dynamic pressure generating unit of the dynamic pressure generating mechanism is released to the one space via the fluid recovery mechanism, thereby suppressing the pressure on the one space side of the sliding surface. Furthermore, because the dynamic pressure generating mechanism is connected to the fluid recovery mechanism as well as the one space, a sufficient amount of fluid is supplied to the dynamic pressure generating mechanism, ensuring the generation of positive pressure. Therefore, twisting such that one space side of the sliding surface moves away from the mating sliding surface and the other space side moves closer to the mating sliding surface is unlikely to occur, and the parallelism between the sliding surfaces can be maintained.

[0009] The fluid recovery mechanism may be formed to be long in the circumferential direction, whereby the fluid between the sliding surfaces can be easily recovered by the flow of fluid within the fluid recovery mechanism.

[0010] The fluid recovery mechanism may be a deep groove, which can take in a large amount of fluid between the sliding surfaces, making it easier to reduce the pressure in one space on the sliding surfaces.

[0011] The dynamic pressure generating mechanism may be composed of a fluid inlet groove communicating with the one space and a dynamic pressure generating groove extending circumferentially from the fluid inlet groove and shallower than the fluid inlet groove, and the fluid recovery mechanism may be in communication with the fluid inlet groove. This allows the sealed fluid to be efficiently introduced from the deep fluid inlet groove to the dynamic pressure generating groove, thereby enhancing the dynamic pressure generating effect in the dynamic pressure generating portion. Furthermore, since the fluid recovery mechanism is in communication with the deep fluid inlet groove, it is possible to suppress the fluid recovery mechanism from affecting the dynamic pressure generating effect of the dynamic pressure generating portion.

[0012] The fluid recovery mechanism may be in communication with the fluid introduction grooves that are adjacent to each other in the circumferential direction, which makes it easier to reduce the pressure in one space on the sliding surface uniformly in the circumferential direction.

[0013] 1 is a schematic cross-sectional view showing a shaft sealing device to which a seal ring according to a first embodiment of the present invention is applied. (a) is a view of the seal ring from the axial direction, (b) is an enlarged view of the cut portion from the axial direction, and (c) is a view as viewed from the arrow A. (a) is an enlarged view of the dynamic pressure generating groove and the fluid recovery groove in the first embodiment to which the seal ring is applied from the axial direction, and (b) is a cross-sectional view taken along the line B-B. (b) is a schematic cross-sectional view showing a state in which dynamic pressure is generated by the dynamic pressure generating groove. (c) is an enlarged view of the dynamic pressure generating groove and the fluid recovery groove in the second embodiment of the present invention to which the seal ring according to a first embodiment of the present invention is applied. (c) is a schematic cross-sectional view of the dynamic pressure generating groove and the fluid recovery groove in the fifth embodiment of the present invention to which the seal ring according to a sixth embodiment of the present invention is applied. (c) is a schematic cross-sectional view of the shaft sealing device to which a seal ring according to a seventh embodiment of the present invention is applied. (c) is an enlarged view of a modified example of the fluid recovery groove in the first embodiment to which the seal ring according to the first embodiment is applied from the axial direction.

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A seal ring according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0015] A seal ring according to a first embodiment will be described with reference to Figures 1 to 4. In this embodiment, the right side of the paper in Figure 1 will be the right side of the seal ring, and the left side of the paper in Figure 1 will be the left side of the seal ring. For ease of explanation, the dynamic pressure generating grooves 36, the fluid recovery grooves 37, etc. are illustrated larger than they actually are.

[0016] The shaft seal device shown in Fig. 1 can be suitably used, for example, in a rotating machine to seal the annular gap between a rotating shaft 1 and a housing 2 that rotate relative to each other in order to maintain hydraulic pressure. In this embodiment, an example in which the device is applied to such an application will be described. Note that Fig. 1 shows a state in which no dynamic pressure is generated in the dynamic pressure generating groove 36 of the seal ring 3.

[0017] The shaft seal device is mainly composed of a rotating shaft 1, a housing 2, and a seal ring 3. The seal ring 3 is loosely fitted into an annular groove 1A having a rectangular cross section provided in the rotating shaft 1.

[0018] As will be described later, the right surface 3a serving as the sliding surface of the seal ring 3 slides against the right surface 1a serving as the mating sliding surface that constitutes the annular groove 1A, and the outer peripheral surface 3b serving as the installation surface of the seal ring 3 is pressed against the inner peripheral surface 2a serving as the installed surface of the housing 2. In other words, it is sufficient that the installation surface and the installed surface are in contact with each other, and the seal ring 3 is assembled in a state that allows circumferential sliding between the installation surface and the installed surface in situations where there is insufficient lubrication of the sliding surfaces, such as when starting up the equipment.

[0019] The right surface 3a of the seal ring 3 has a portion that abuts against the right surface 1a of the annular groove 1A and a portion that is located radially outward of the right surface 1a of the annular groove 1A, and the sliding surface of the seal ring 3 in this embodiment refers to the entire right surface 3a of the seal ring 3. In other words, the sliding surface of the seal ring 3 includes the portion that abuts against the right surface 1a of the annular groove 1A and a portion that is flush with the portion that abuts against the right surface 1a of the annular groove 1A.

[0020] In addition, the corners between the outer peripheral surface 3b and the right surface 3a of the seal ring 3 and the corners between the outer peripheral surface 3b and the left surface are cut out to form steps. This makes it easier to maintain the pressure contact state between the outer peripheral surface 3b and the inner peripheral surface 2a. This is because the seal ring 3 itself can undergo slight deformation when an external force such as fluid pressure acts on it.

[0021] 1 is configured to change the fluid pressure in the region on the left side of the drawing, and the seal ring 3 plays a role in maintaining the fluid pressure in the region to be sealed (H) on the left side of the drawing. The region to be sealed (H) as one space is located on the opposite side of the outer peripheral surface 3b with respect to the right surface 3a of the seal ring 3, and the leakage region (L) as the other space is located on the outer peripheral surface 3b side with respect to the right surface 3a of the seal ring 3.

[0022] Although not shown, when the equipment using the seal ring 3 is stopped, the fluid pressure in the sealed area (H) is low and is the same pressure as the leakage area (L) on the right side of Figure 1, and when the equipment is operating, the fluid pressure in the sealed area (H) is higher than that in the leakage area (L).

[0023] The seal ring 3 is made of a resin material such as polyether ether ketone (PEEK), polyphenylene sulfide (PPS), or polytetrafluoroethylene (PTFE).

[0024] 2(a) to 2(c), a cut portion 31 is formed at one location in the circumferential direction of the seal ring 3. Note that Fig. 2(b) is an enlarged view of the enclosed area in Fig. 2(a).

[0025] The cut portion 31 is a known special step cut that is cut in a stepped manner when viewed from both axial sides (see FIGS. 2(a) and 2(b)) and the outer diameter side (see FIG. 2(c)). As a result, in the seal ring 3, a first fitting convex portion 32 and a first fitting recessed portion 33 are provided on the outer peripheral surface side on one circumferential side, and a second fitting recessed portion 34 into which the first fitting convex portion 32 fits and a second fitting convex portion 35 which fits into the first fitting recessed portion 33 are provided on the outer peripheral surface side on the other circumferential side.

[0026] The cut portion 31 may be formed by molding as well as by cutting. While a special step cut is shown as an example of the cut portion 31, it is not limited to this, and well-known straight cuts, bias cuts, step cuts, etc. may also be used. If a low-elasticity material (such as PTFE) is used as the material for the seal ring 3, the cut portion need not be provided.

[0027] 2(b) and 3, a plurality of dynamic pressure generating grooves 36 serving as dynamic pressure generating mechanisms and a plurality of fluid recovery grooves 37 serving as fluid recovery mechanisms are formed in the circumferential direction on the right surface 3a of the seal ring 3. In this embodiment, a plurality of sets of one dynamic pressure generating groove 36 and one fluid recovery groove 37 disposed downstream of the dynamic pressure generating groove 36 in the direction of rotation of the rotating shaft 1 are formed in the circumferential direction on the right surface 3a of the seal ring 3.

[0028] It is possible to freely change the numbers of the dynamic pressure generating grooves 36 and the fluid recovery grooves 37. For example, the number of the dynamic pressure generating grooves 36 and the number of the fluid recovery grooves 37 provided on the right surface 3a of the seal ring 3 may be different.

[0029] As shown in particular in FIGS. 3(a) and 3(b), the dynamic pressure generating groove 36 includes a first groove portion 38 serving as a fluid introduction groove and a second groove portion 39 serving as a dynamic pressure generating groove.

[0030] The first groove 38 extends radially in a straight line from an inner diameter end 38 a to an outer diameter end 38 b. The inner diameter end 38 a communicates with the region to be sealed (H). The outer diameter side of the outer diameter end 38 b is closed by a land 40.

[0031] The second groove portion 39 extends in an arc shape from the outer diameter end 38b of the first groove portion 38 toward the downstream side in the rotation direction of the rotating shaft 1. The second groove portion 39 is formed so that its circumferential length is longer than its radial groove width.

[0032] The second groove 39 becomes shallower from the upstream side to the downstream side in the rotation direction of the rotating shaft 1. Specifically, the bottom surface 39a of the second groove 39 extends linearly from the side wall of the first groove 38 to the land 40 (see FIG. 3B in particular). The bottom surface 39a of the second groove 39 may be stepped.

[0033] An end 39b of this second groove portion 39 is disposed radially outward from the center of the radial width on the right surface 3a of the seal ring 3. In other words, the end 39b of the second groove portion 39 serving as a pressure generating portion is disposed closer to the radially outer side of the right surface 3a of the seal ring 3, i.e., the leakage region (L) side.

[0034] As shown in Figure 3(b), the depth D1 of the first groove portion 38 is deeper than the depth D2 of the second groove portion 39 (D1 > D2). Specifically, the depth D1 of the first groove portion 38 is approximately 25 times the depth D2 of the second groove portion 39. Note that the depth D2 of the second groove portion 39 here refers to the depth of the deepest portion of the second groove portion 39. For ease of explanation, the depth D2 of the second groove portion 39 is illustrated exaggerated in Figure 3(b) than it actually is.

[0035] The fluid recovery groove 37 extends in an arc shape from the inner diameter end 38a of the first groove portion 38 toward the upstream side in the rotation direction of the rotating shaft 1. The circumferential component of the fluid recovery groove 37 is larger than the radial component. Note that the fluid recovery groove 37 is not limited to an arc shape when viewed in the axial direction, and may extend, for example, linearly when viewed in the axial direction.

[0036] The fluid recovery groove 37 communicates with the area to be sealed (H) along the circumferential direction.

[0037] Furthermore, the fluid recovery groove 37 and the first groove portion 38 of the adjacent dynamic pressure generating groove 36 on the upstream side in the relative rotational direction are partitioned in the circumferential direction by a land 40 .

[0038] 1 and 3B, the depth D3 of the fluid recovery groove 37 is the same as the depth D1 of the first groove portion 38 (D1=D3).

[0039] In this embodiment, the depth D1 of the first groove portion 38 and the depth D3 of the fluid recovery groove 37 are approximately 25 times the depth D2 of the second groove portion 39, but these may be freely changed, and are preferably approximately 5 to 50 times deeper.

[0040] The fluid recovery groove 37 is disposed on the inner diameter side of the center of the radial width on the right surface 3 a of the seal ring 3. In other words, the fluid recovery groove 37 is disposed closer to the inner diameter side of the right surface 3 a of the seal ring 3, i.e., closer to the area to be sealed (H).

[0041] Furthermore, since it is essential that the dynamic pressure generating grooves 36 generate dynamic pressure over a wide radial range on the right face 3 a, as described above, they are arranged on the outer diameter side of the center of the radial width on the right face 3 a. On the other hand, since it is only necessary for the fluid recovery grooves 37 to suppress excessive pressure on the inner diameter side of the right face 3 a, they only need to be arranged on the inner diameter side of the dynamic pressure generating grooves 36, and as described above, it is even more preferable that the fluid recovery grooves 37 are arranged on the inner diameter side of the center of the radial width on the right face 3 a of the seal ring 3.

[0042] When the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A slide relative to each other, oil in the dynamic pressure generating groove 36 moves toward the end 39b of the second groove portion 39, generating positive pressure at and near the end 39b. This causes a slight separation between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A (see FIG. 4), and an oil film is formed, reducing the friction between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A. Oil is constantly supplied to the second groove portion 39 from the sealed area (H) through the first groove portion 38.

[0043] On the other hand, part of the oil in the fluid recovery groove 37 moves from the end 37b towards the first groove portion 38, and the other part is discharged into the area to be sealed (H).

[0044] In this way, a flow occurs within the fluid recovery groove 37 from the end 37b toward the first groove portion 38, which allows the fluid near the fluid recovery groove 37 to be recovered.As a result, as shown in Figure 4, the positive pressure generated in the dynamic pressure generating groove 36 can be reduced on the inner diameter side between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A, i.e., the pressure on the side of the area to be sealed (H).

[0045] When the pressure inside the fluid recovery groove 37 becomes relatively negative, oil is supplied from the area to be sealed (H). In other words, the pressure inside the fluid recovery groove 37 is the same as the pressure inside the area to be sealed (H).

[0046] Next, the state of the seal ring 3 when the rotating shaft 1 rotates will be described with reference to FIGS.

[0047] 1 , when the device is operated, the fluid pressure in the area to be sealed (H) becomes higher than that in the leakage area (L), and the seal ring 3 is subjected to a force in the radial direction by the fluid pressure in the area to be sealed (H), and the outer peripheral surface 3b of the seal ring 3 is pressed against the inner peripheral surface 2a of the housing 2. In other words, the seal ring 3 is fixed to the housing 2.

[0048] Further, the right surface 3a of the seal ring 3 is pressed against the right surface 1a of the annular groove 1A in the rotating shaft 1 by the fluid pressure in the area to be sealed (H) and slides thereon.

[0049] 4, when the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A slide relative to each other, dynamic pressure is generated by the dynamic pressure generating groove 36, and the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A are slightly spaced apart. For ease of explanation, the distance between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A is shown larger than it actually is in FIG.

[0050] The right surface 3a of the seal ring 3 has a larger diameter than the right surface 1a of the annular groove 1A, and no dynamic pressure generating groove 36 is provided in the portion of the right surface 3a of the seal ring 3 that protrudes radially outward from the right surface 1a of the annular groove 1A. As a result, a greater dynamic pressure acts on the inner diameter side of the right surface 3a of the seal ring 3 than on the outer diameter side. In other words, a twisting force acts on the seal ring 3 such that the inner diameter side of the right surface 3a of the seal ring 3 is greater than the outer diameter side and moves away from the right surface 1a of the annular groove 1A.

[0051] In detail, a force acts on the seal ring 3 to tilt the right surface 3a of the seal ring 3 relative to the right surface 1a of the annular groove 1A so that the inner diameter portion of the seal ring 3 relative to the center point P of its cross section moves away from the right surface 1a of the annular groove 1A and the outer diameter portion of the seal ring 3 relative to the center point P moves closer to the right surface 1a of the annular groove 1A.

[0052] In the first embodiment, a fluid recovery groove 37 is provided on the right surface 3a of the seal ring 3, closer to the region to be sealed (H) than the end 39b of the second groove portion 39 of the dynamic pressure generating groove 36. With this, the pressure on the region to be sealed (H) side out of the positive pressure generated near the end 39b of the second groove portion 39 is released to the region to be sealed (H) through the fluid recovery groove 37, so that the pressure on the region to be sealed (H) side between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A can be suppressed.

[0053] Therefore, it is difficult for the right surface 3a of the seal ring 3 to twist so that the sealed area (H) side of the right surface 3a of the seal ring 3 moves away from the right surface 1a of the annular groove 1A and the leakage area (L) side moves closer to it, and it is possible to maintain parallelism between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A. This makes it possible to avoid contact between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A and to prevent a decrease in the dynamic pressure effect of the dynamic pressure generating groove 36.

[0054] Furthermore, since the first groove portion 38 of the dynamic pressure generating groove 36 is connected to the fluid recovery groove 37 in addition to the area to be sealed (H), sufficient fluid is supplied to the dynamic pressure generating groove 36, thereby ensuring the generation of positive pressure.

[0055] Furthermore, the fluid recovery groove 37 has a circumferential component that is larger than its radial component, i.e., is formed long in the circumferential direction, so that the fluid between the right faces 1 a, 3 a can be recovered over a wide range in the circumferential direction of the fluid recovery groove 37.

[0056] Furthermore, the fluid recovery groove 37 is a deep groove, which prevents dynamic pressure from being generated near the inner diameter end 38a of the first groove portion 38 between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A, thereby efficiently reducing the pressure on the sealed region (H) side. Furthermore, the fluid can be recovered by the entire fluid recovery groove 37.

[0057] Furthermore, the dynamic pressure generating groove 36 has a first groove portion 38 and a second groove portion 39, and since the first groove portion 38 is a deep groove, oil can be efficiently introduced from the first groove portion 38 to the second groove portion 39, and therefore the dynamic pressure generating effect in the second groove portion 39 is high.

[0058] Furthermore, since the fluid recovery groove 37 is connected to the first groove portion 38 which is a deep groove, the influence of the fluid recovery groove 37 on the dynamic pressure generating effect of the second groove portion 39 can be suppressed.

[0059] In addition, since the second groove portion 39 becomes shallower from the upstream side to the downstream side in the rotation direction of the rotating shaft 1, the wedge effect of the second groove portion 39 makes it possible to generate dynamic pressure efficiently.

[0060] Furthermore, the fluid recovery groove 37 overlaps with the second groove portion 39 of the adjacent dynamic pressure generating groove 36 on the upstream side in terms of relative rotation when viewed from the radial direction. This allows the sets of the dynamic pressure generating groove 36 and the fluid recovery groove 37 that are adjacent on the upstream side in terms of relative rotation to be positioned close to each other in the circumferential direction.

[0061] While this embodiment illustrates an embodiment in which the dynamic pressure generating grooves 36 and the fluid recovery grooves 37 are provided only on the right surface 3a of the seal ring 3, the dynamic pressure generating grooves and the fluid recovery grooves may also be provided on the left surface of the seal ring 3. In this case, for example, when the pressure balance between the regions on both sides is reversed from the state shown in Figure 1, the seal ring 3 moves to the left, and its left surface comes into contact with and slides on the left surface of the annular groove 1A, generating dynamic pressure in the dynamic pressure generating grooves on the left side while recovering fluid through the fluid recovery grooves on the left side. In addition, assembly can be performed either upside down, improving work efficiency.

[0062] Furthermore, in this embodiment, the depth of the second groove portion 39 of the dynamic pressure generating groove 36 is illustrated as gradually becoming shallower from the upstream side of the relative rotation toward the downstream side of the relative rotation, but the depth may be constant.

[0063] Furthermore, in this embodiment, the depth of the fluid recovery groove 37 is the same as the depth of the first groove portion 38 of the dynamic pressure generating groove 36, but the depths of the first groove portion 38 and the dynamic pressure generating groove 36 may be different. For example, the fluid recovery groove may be a shallow groove, and a relative negative pressure may be generated in the fluid recovery groove during relative rotation, thereby enhancing the fluid recovery effect of the fluid recovery groove.

[0064] Next, a seal ring according to a second embodiment will be described with reference to Fig. 5. Note that the description of the same configuration as in the first embodiment will be omitted.

[0065] 5, a dynamic pressure generating groove 236 and a fluid recovery groove 237 are provided on a right surface 203a of a seal ring 203 of the second embodiment. The dynamic pressure generating groove 236 has the same configuration as the dynamic pressure generating groove 36 of the first embodiment.

[0066] The fluid recovery groove 237 extends in an arc shape from the inner diameter end 238a of the first groove portion 238 toward the upstream side in the rotation direction of the rotating shaft 1. Furthermore, the upstream end of the fluid recovery groove 237 in the relative rotation direction communicates with the first groove portion 238 of the adjacent dynamic pressure generation groove 236 on the upstream side in the relative rotation direction.

[0067] That is, the fluid recovery groove 237 is formed in an annular shape around the entire circumference of the right surface 203a. This makes it easy to reduce the pressure on the sealed area (H) side between the right surface 203a of the seal ring 203 and the right surface 1a of the annular groove 1A evenly in the circumferential direction. Also, a circumferential flow is easily generated in the fluid recovery groove 237, making it easy to maintain the same pressure in the circumferential direction inside the fluid recovery groove 237.

[0068] Next, a seal ring according to a third embodiment will be described with reference to Fig. 6. Note that the configuration is the same as that of the first embodiment, and therefore a description of the configuration that overlaps with the first embodiment will be omitted.

[0069] 6, a dynamic pressure generating groove 336 and a fluid recovery groove 337 are provided on a right surface 303a of a seal ring 303 of the third embodiment. The dynamic pressure generating groove 336 has the same configuration as the dynamic pressure generating groove 36 of the first embodiment.

[0070] The fluid recovery groove 337 extends in an arc shape from the first groove portion 338 toward the upstream side in the rotation direction of the rotating shaft 1. The fluid recovery groove 337 and the area to be sealed (H) are partitioned by the land 340. In other words, the fluid recovery groove 337 communicates with the area to be sealed (H) via the first groove portion 338.

[0071] Fluid can be recovered near the fluid recovery groove 337 by flowing from the upstream end 337b of the fluid recovery groove 337 in relation to the relative rotation toward the first groove portion 338, so that even if the fluid recovery groove 337 does not directly communicate with the area to be sealed (H), it is possible to reduce the pressure on the side of the area to be sealed (H) between the right surface 303a of the seal ring 303 and the right surface 1a of the annular groove 1A. In addition, because the land 340 is present on the inner diameter side of the fluid recovery groove 337, the fluid in the fluid recovery groove 337 is more likely to be retained even if the pressure of the fluid in the area to be sealed (H) fluctuates.

[0072] Next, a seal ring according to a fourth embodiment will be described with reference to Fig. 7. Note that the configuration is the same as that of the third embodiment, and therefore a description of the configuration that overlaps with the third embodiment will be omitted.

[0073] 7, a dynamic pressure generating groove 436 and a fluid recovery groove 437 are provided on a right surface 403a of a seal ring 403 of the fourth embodiment. The dynamic pressure generating groove 436 has the same configuration as the dynamic pressure generating groove 36 of the first embodiment.

[0074] The upstream end of the fluid recovery groove 437 in the relative rotation direction is connected to the first groove portion 438 of the adjacent dynamic pressure generating groove 436 on the upstream side in the relative rotation direction. The fluid recovery groove 437 and the area to be sealed (H) are separated by a land 440.

[0075] This allows the pressure on the sealed region (H) side between the right surface 403a of the seal ring 403 and the right surface 1a of the annular groove 1A to be reduced uniformly in the circumferential direction.

[0076] Furthermore, a circumferential flow is likely to occur in the fluid recovery groove 437, and the pressure inside the fluid recovery groove 437 tends to be uniform throughout the circumferential direction.

[0077] Furthermore, since the land 440 is present on the inner diameter side of the fluid recovery groove 437, the fluid in the fluid recovery groove 437 is easily retained even if the pressure of the fluid in the area to be sealed (H) fluctuates.

[0078] Next, a seal ring according to a fifth embodiment will be described with reference to Fig. 8. Note that the configuration is the same as that of the third embodiment, and therefore a description of the configuration that overlaps with the third embodiment will be omitted.

[0079] 8, a dynamic pressure generating groove 536 and a fluid recovery groove 537 are provided on a right surface 503a of a seal ring 503 of the fifth embodiment. The dynamic pressure generating groove 536 has the same configuration as the dynamic pressure generating groove 36 of the first embodiment.

[0080] A land 540 provided between the fluid recovery groove 537 and the area to be sealed (H) is provided with a radially extending communication groove 541. The communication groove 541 radially connects the fluid recovery groove 537 and the area to be sealed (H).

[0081] In this way, since the fluid recovery groove 537 is connected to the sealed area (H) in part of its circumferential direction by the connecting groove 541, it is easy to reduce the pressure on the sealed area (H) side between the right surface 503a of the seal ring 503 and the right surface 1a of the annular groove 1A.

[0082] Furthermore, since the land 540 is present on the inner diameter side of the fluid recovery groove 537, the fluid in the fluid recovery groove 537 is easily retained even if the pressure of the fluid in the area to be sealed (H) fluctuates.

[0083] Next, a seal ring according to a sixth embodiment will be described with reference to Fig. 9. Note that the description of the same configuration as in the first embodiment will be omitted.

[0084] As shown in Figure 9, the seal ring 603 of this embodiment 6 is configured so that the right surface 603a, which serves as the installation surface, is pressed against the right surface 1a of the annular groove 1A in the rotating shaft 1 by fluid pressure, and rotates together with the rotating shaft 1.

[0085] This seal ring 603 has a dynamic pressure generating groove 636 and a fluid recovery groove 637 formed on an outer peripheral surface 603b serving as a sliding surface. These dynamic pressure generating groove 636 and fluid recovery groove 637 communicate with a region to be sealed (H) on the outer peripheral surface 603b opposite to the right surface 603a.

[0086] When the seal ring 603 rotates together with the rotating shaft 1, the outer peripheral surface 603b of the seal ring 603 slides against the inner peripheral surface 2a of the housing 2, generating dynamic pressure in the dynamic pressure generating groove 636, causing the outer peripheral surface 603b of the seal ring 603 and the inner peripheral surface 2a of the housing 2 to separate, forming an oil film.

[0087] At this time, the fluid between the outer peripheral surface 603b of the seal ring 603 and the inner peripheral surface 2a of the housing 2 is recovered by the fluid recovery groove 637 on the side of the area to be sealed (H) closer to the dynamic pressure generating groove 636, and the pressure on the side of the area to be sealed (H) decreases, thereby suppressing the inclination between the outer peripheral surface 603b of the seal ring 603 and the inner peripheral surface 2a of the housing 2.

[0088] Next, a seal ring according to a seventh embodiment will be described with reference to Fig. 10. Note that the description of the same configuration as that of the first embodiment will be omitted.

[0089] 10, in the shaft seal device of the seventh embodiment, an annular groove 72A is formed in a housing 72, and a seal ring 703 is disposed in the annular groove 72A. The outer peripheral surface 71a of the rotating shaft 71 extends flat in the axial direction.

[0090] An inner peripheral surface 703 d serving as a mounting surface of the seal ring 703 is pressed against the outer peripheral surface 71 a of the rotary shaft 71 by fluid pressure, and rotates together with the rotary shaft 71 .

[0091] A right surface 703a of the seal ring 703 as a sliding surface comes into contact with the right surface 72a of the annular groove 72A due to fluid pressure, and is capable of sliding relative to the right surface 72a.

[0092] A dynamic pressure generating groove 736 and a fluid recovery groove 737 are formed on the right surface 703a of the seal ring 703. The dynamic pressure generating groove 736 and the fluid recovery groove 737 communicate with the area to be sealed (H) on the right surface 703a opposite the inner circumferential surface 703d.

[0093] When the seal ring 703 rotates together with the rotating shaft 71, the right surface 703a of the seal ring 703 slides against the right surface 72a of the annular groove 72A, generating dynamic pressure in the dynamic pressure generating groove 736, causing the right surface 703a of the seal ring 703 and the right surface 72a of the annular groove 72A to separate, forming an oil film.

[0094] At this time, the fluid between the right surface 703a of the seal ring 703 and the right surface 72a of the annular groove 72A is recovered by the fluid recovery groove 737 on the side of the area to be sealed (H) closer to the dynamic pressure generating groove 736, thereby reducing the pressure on the side of the area to be sealed (H), thereby suppressing the inclination between the right surface 703a of the seal ring 703 and the right surface 72a of the annular groove 72A.

[0095] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0096] For example, in the first to seventh embodiments, the sliding surface and the installation surface of the seal ring are perpendicular to each other, but they are not limited to being perpendicular as long as they extend in directions that intersect each other.

[0097] Furthermore, in the above-described Examples 1 to 7, the configuration in which the shaft rotates relative to the housing is exemplified, but the housing may also rotate relative to the shaft, or both the shaft and the housing may rotate in a relative rotation direction.

[0098] Furthermore, in the first to seventh embodiments, the fluid recovery mechanism has been exemplified as having a circumferential component greater than a radial component, but the radial component may be greater than the circumferential component.

[0099] Furthermore, in the first to seventh embodiments, the dynamic pressure generating mechanism is configured from a fluid introduction groove and a dynamic pressure generating groove, but it may also be, for example, a spiral groove.

[0100] Furthermore, while the fluid recovery mechanism in Examples 1 to 7 has a constant depth, the depth may vary. For example, as shown in FIG. 11 , the fluid recovery groove 837 may gradually become shallower from the downstream end 838a of the relative rotation to the upstream end 837b of the relative rotation. This allows a relative negative pressure to be generated at the upstream end 837b of the fluid recovery groove 837, making it easier to capture fluid between the sliding surfaces. Furthermore, because the downstream end 838a is a deep groove, dynamic pressure is less likely to be generated near the downstream end 838a.

[0101] DESCRIPTION OF SYMBOLS 1 Rotating shaft (shaft) 1A Annular groove 1a Right surface (sliding surface) 2 Housing 2a Inner peripheral surface (mounting surface) 3 Seal ring 3a Right surface (sliding surface) 3b Outer peripheral surface (mounting surface) 36 Dynamic pressure generating groove (dynamic pressure generating mechanism) 37 Fluid recovery groove (fluid recovery mechanism) 38 First groove portion (fluid introduction groove) 39 Second groove portion (dynamic pressure generating groove) 39b End portion (dynamic pressure generating portion) 40 Land

Claims

1. A seal ring having a sliding surface which rotates and slides relative to a shaft or a housing through which the shaft is inserted, and an installation surface which intersects with the sliding surface and is installed on the other side of the shaft and the housing, separating one space located on the opposite side of the sliding surface to the side which intersects with the installation surface, and another space located on the intersecting side, wherein the sliding surface is equipped with a dynamic pressure generating mechanism which has a dynamic pressure generating part and communicates with the one space, and a fluid recovery mechanism which is located on the side of the one space relative to the dynamic pressure generating part and communicates with the upstream side of the dynamic pressure generating mechanism in terms of relative rotation.

2. The seal ring according to claim 1, wherein said fluid recovery mechanism is formed long in the circumferential direction.

3. The seal ring of claim 1, wherein said fluid recovery feature is a deep groove.

4. A seal ring as described in any one of claims 1 to 3, wherein the dynamic pressure generating mechanism is composed of a fluid inlet groove communicating with the one space, and a dynamic pressure generating groove extending circumferentially from the fluid inlet groove and shallower than the fluid inlet groove, and the fluid recovery mechanism is connected to the fluid inlet groove.

5. A seal ring according to claim 1, wherein said fluid recovery mechanism is in communication with adjacent ones of said fluid introduction grooves in the circumferential direction.

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