Seal ring

Abstract

The present invention provides a seal ring capable of maintaining parallelism between sliding surfaces.　Provided is a seal ring having a sliding surface 3a that slides, in relative fashion, with a shaft 1 or a housing 2 into which the shaft 1 is inserted, and an installation surface 3b that crosses the sliding surface 3a and that is installed on the other of the shaft 1 and the housing 2, the seal ring partitioning a gap between one space H located on the side of the sliding surface 3a that is opposite to the side crossing the installation surface 3b and another space L disposed on the crossing side, wherein the sliding surface 3a is provided with a dynamic pressure generation mechanism 36 that communicates with the one space H and that has a dynamic pressure generation part 39b, and a fluid recovery mechanism 37 disposed between the dynamic pressure generation part 39b and the one space H.

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 present invention provides a seal ring having 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 the sliding surface and is installed on the other of the shaft and the housing, and that separates a first space located on the sliding surface opposite the side that intersects with the installation surface from a second 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 first space, and a fluid recovery mechanism that is located between the dynamic pressure generating unit and the first space. In this way, the pressure on the first space side of the sliding surface, of the positive pressure generated near the dynamic pressure generating unit of the dynamic pressure generating mechanism, is released by the pressure difference with the first space via the fluid recovery mechanism, thereby suppressing the pressure on the first space side. Furthermore, the fluid recovery mechanism is surrounded by lands, which makes it less likely to interfere with the dynamic pressure generating mechanism during relative rotation and less likely to be affected by the first space when the device is stopped. 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 disposed closer to the one space, which makes it easier to discharge the fluid in the fluid recovery mechanism into the one space.

[0010] The width of the land between the fluid recovery mechanism and the one space may be smaller than the width of the fluid recovery mechanism, which makes it easier to discharge the fluid in the fluid recovery mechanism into the one space.

[0011] The fluid recovery mechanism may be formed to be long in the circumferential direction, whereby a flow of fluid toward the downstream side of the relative rotation in the circumferential direction occurs within the fluid recovery mechanism, and the flow of fluid within the fluid recovery mechanism makes it easier to recover the fluid between the sliding surfaces.

[0012] The fluid recovery mechanism may be disposed so that an end portion on the downstream side of the relative rotation faces the one space, thereby making it easier to discharge the fluid within the fluid recovery mechanism into the one space.

[0013] The fluid recovery mechanism may have a depth that decreases from the downstream side of the relative rotation to the upstream side of the relative rotation, which allows a relative negative pressure to be generated on the upstream side of the relative rotation of the fluid recovery mechanism, making it easier to take in fluid between the sliding surfaces.

[0014] 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 on one side of the space on the sliding surfaces.

[0015] The dynamic pressure generating mechanism may be composed of a fluid introduction groove communicating with the one space, and a dynamic pressure generating groove extending circumferentially from the fluid introduction groove and shallower than the fluid introduction groove. In this way, the sealed fluid can be efficiently introduced from the deep fluid introduction groove to the dynamic pressure generating groove, thereby increasing the dynamic pressure generation effect in the dynamic pressure generating portion.

[0016] The dynamic pressure generating groove may be shallower from the upstream side of the relative rotation to the downstream side of the relative rotation, thereby increasing the dynamic pressure generating effect in the dynamic pressure generating portion.

[0017] 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 be viewed 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 be viewed from the axial direction. (c) is an enlarged view of the dynamic pressure generating groove and the fluid recovery groove in the third embodiment of the present invention to be viewed from the axial direction. (d) is an enlarged view of the dynamic pressure generating groove and the fluid recovery groove in the fourth embodiment of the present invention to be viewed from the axial direction. (d) is an enlarged view of the dynamic pressure generating groove and the fluid recovery groove in the fifth embodiment of the present invention to be viewed from the axial direction. (c) is a schematic cross-sectional view showing a shaft sealing device to which a seal ring according to a seventh embodiment of the present invention is applied. (c) is a schematic cross-sectional view showing a shaft sealing device to which a seal ring according to an eighth embodiment of the present invention is applied. (d) is an enlarged view of a modified example of the fluid recovery groove in the first embodiment to be viewed from the axial direction.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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 manner that allows 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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).

[0027] The seal ring 3 is made of a resin material such as polyether ether ketone (PEEK), polyphenylene sulfide (PPS), or polytetrafluoroethylene (PTFE).

[0028] 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).

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The fluid recovery groove 37 is provided between the end 39b of the second groove portion 39 and the area to be sealed (H).

[0040] More specifically, the fluid recovery groove 37 extends from the inner diameter side toward the outer diameter side, inclining toward the upstream side in the direction of rotation of the rotating shaft 1. In other words, the inner diameter end 37a, which is the end of the fluid recovery groove 37 on the downstream side in terms of relative rotation, is located closer to the inner diameter side than the outer diameter end 37b, which is the end on the upstream side in terms of relative rotation, i.e., closer to the region to be sealed (H).

[0041] The fluid recovery groove 37 is formed in an arc shape that is convex toward the outer diameter side when viewed in the axial direction. 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 being arc-shaped when viewed in the axial direction, and may, for example, extend linearly when viewed in the axial direction.

[0042] The entire periphery of the fluid recovery groove 37 is closed by the land 40. In other words, the fluid recovery groove 37 does not communicate with the dynamic pressure generating groove 36 and the area to be sealed (H).

[0043] The outer diameter end 37b of this fluid recovery groove 37 is located on the inner diameter side of the center of the radial width on the right surface 3a of the seal ring 3. In other words, the outer diameter end 37b of the fluid recovery groove 37 is located closer to the inner diameter side of the right surface 3a of the seal ring 3, i.e., the side of the area to be sealed (H).

[0044] The land 401, which radially separates the inner diameter end 37a of the fluid recovery groove 37 from the area to be sealed (H), has a radial width L1. In other words, the radial width L1 can be said to be the shortest distance between the fluid recovery groove 37 and the area to be sealed (H).

[0045] Furthermore, a land 402 that radially separates the inner diameter end 37a of the fluid recovery groove 37 from the end 39b of the second groove portion 39 has a radial width L2.

[0046] The radial width L1 of the land 401 is smaller than the radial width L2 of the land 402 (L1<L2). In this embodiment, the radial width L1 is approximately 1 / 30 times the radial width L2, but this can be freely changed. Preferably, the radial width L1 is approximately 1 / 2 to 1 / 50 times the radial width L2.

[0047] Furthermore, the radial width L1 of the land 401 is smaller than the groove width L3 of the fluid recovery groove 37 (L1<L3). In this embodiment, the radial width L1 is approximately 1 / 10 of the groove width L3, but this can be freely changed. Preferably, the radial width L1 is approximately 1 / 2 to 1 / 20 of the radial width L2.

[0048] 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).

[0049] 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.

[0050] Furthermore, since it is essential that the dynamic pressure generating groove 36 generates dynamic pressure over a wide radial range on the right face 3 a, as described above, it is disposed 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 groove 37 to suppress excessive pressure on the inner diameter side of the right face 3 a, it is sufficient that it is disposed on the inner diameter side of the dynamic pressure generating groove 36, and as described above, it is even more preferable that the outer diameter end 37 b is disposed on the inner diameter side of the center of the radial width on the right face 3 a of the seal ring 3.

[0051] 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.

[0052] On the other hand, the oil in the fluid recovery groove 37 moves from the outer diameter end 37b toward the inner diameter end 37a, and is discharged over the land 401 into the area to be sealed (H).

[0053] In this way, a flow occurs within the fluid recovery groove 37 from the outer diameter end 37b toward the inner diameter end 37a, which causes the fluid near the fluid recovery groove 37 to be recovered.As a result, as shown in FIG. 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).

[0054] Next, the state of the seal ring when the rotating shaft 1 rotates will be described with reference to FIG.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] In the first embodiment, a fluid recovery groove 37 is provided on the right surface 3a of the seal ring 3 between the region to be sealed (H) and 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.

[0061] Furthermore, the radial width L1 of the land 401 is smaller than the radial width L2 of the land 402. In other words, the fluid recovery groove 37 is disposed on the right surface 3 a of the seal ring 3 closer to the area to be sealed (H). This makes it easier for the oil in the fluid recovery groove 37 to be discharged to the area to be sealed (H). As a result, the oil in the fluid recovery groove 37 is discharged from the inner diameter end 37 a, over the land 401, and immediately into the area to be sealed (H), making it difficult for dynamic pressure to be generated near the inner diameter end 37 a.

[0062] Furthermore, since the radial width L1 of the land 401 is smaller than the groove width L3 of the fluid recovery groove 37, the fluid recovery groove 37 is positioned closer to the area to be sealed (H), making it easier to discharge the oil in the fluid recovery groove 37 into the area to be sealed (H).

[0063] 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.

[0064] In addition, the inner diameter end 37a of the fluid recovery groove 37 is positioned closer to the area to be sealed (H) than the outer diameter end 37b, and the oil in the fluid recovery groove 37 flows from the outer diameter end 37b toward the inner diameter end 37a, so the oil in the fluid recovery groove 37 can be efficiently discharged into the area to be sealed (H).

[0065] Furthermore, the fluid recovery groove 37 is a deep groove, which prevents dynamic pressure from being generated near the inner diameter end 37a of the fluid recovery groove 37 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 side of the region to be sealed (H). Furthermore, the fluid can be recovered by the entire fluid recovery groove 37.

[0066] 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.

[0067] 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.

[0068] Furthermore, the fluid recovery groove 37 is surrounded by the land 40, i.e., the dynamic pressure generation groove 36 and the fluid recovery groove 37 are not in communication with each other, so that it is possible to avoid mutual obstruction of the fluid flow in the dynamic pressure generation groove 36 and the fluid flow in the fluid recovery groove 37 during relative rotation. Furthermore, when stopped, the fluid recovery groove 37 is less likely to be affected by the sealed area (H).

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] The fluid recovery groove 237 extends in the circumferential direction substantially parallel to the inner peripheral surface of the seal ring 203. This fluid recovery groove 237 is disposed between the second groove portion 239 of the dynamic pressure generating groove 236 and the area to be sealed (H), and is positioned closer to the area to be sealed (H).

[0075] According to this, since the fluid recovery groove 237 is close to the region to be sealed (H) over a wide range in the circumferential direction, the fluid in the fluid recovery groove 237 is easily discharged to the side of the region to be sealed (H).

[0076] In this embodiment, the fluid recovery grooves 237 are arranged parallel to the circumferential direction, but they may be inclined or deformed so that the end on the downstream side of the relative rotation approaches the area to be sealed (H). This allows the direction of fluid flow to be directed toward the area to be sealed (H), making the recovery and discharge of fluid more efficient.

[0077] 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.

[0078] 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.

[0079] The fluid recovery groove 337 has a rectangular shape when viewed in the axial direction. A plurality of fluid recovery grooves 337 (three in this embodiment) are arranged in the circumferential direction between the second groove portion 339 of the dynamic pressure generating groove 336 and the region to be sealed (H) and are positioned closer to the region to be sealed (H).

[0080] In this way, a plurality of fluid recovery grooves 337 may be provided for one dynamic pressure generating groove 336 .

[0081] In this embodiment, a plurality of fluid recovery grooves 337 are provided parallel to the circumferential direction, but they may be arranged in an inclined or stepped pattern so that the downstream end of the relative rotation approaches the area to be sealed (H). This allows the direction of fluid flow to be directed toward the area to be sealed (H), making recovery and discharge of the fluid more efficient.

[0082] 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.

[0083] As shown in FIG. 7, a plurality of fluid recovery grooves 437 (four in this embodiment) are provided for one dynamic pressure generating groove 436 on the right surface 403 a of the seal ring 403 of this embodiment.

[0084] The fluid recovery groove 437 of the fourth embodiment has an elliptical shape that is long in the radial direction when viewed in the axial direction.

[0085] In this way, it is possible to freely change the shape of the fluid recovery groove 437. The fluid recovery groove is not limited to an elliptical shape, and may be a circular shape or the like.

[0086] In this embodiment, a plurality of fluid recovery grooves 437 are provided parallel to the circumferential direction, but they may be arranged in an inclined or stepped pattern so that the downstream end of the relative rotation approaches the area to be sealed (H). This allows the direction of fluid flow to be directed toward the area to be sealed (H), making recovery and discharge of the fluid more efficient.

[0087] 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 first embodiment, and therefore a description of the configuration that overlaps with the first embodiment will be omitted.

[0088] 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 and the fluid recovery groove 537 have the same configurations as the dynamic pressure generating groove 36 and the fluid recovery groove 37 of the first embodiment.

[0089] A narrow groove 510 extending in the circumferential direction is provided in a land 540 between the inner diameter end 537a of the fluid recovery groove 537 and the area to be sealed (H) on the right surface 503a of the seal ring 503. The narrow groove 510 provided between the inner diameter end 537a of the fluid recovery groove 537 and the area to be sealed (H) makes it easier to discharge the fluid toward the area to be sealed (H).

[0090] In this way, even though a narrow groove 510 is provided between the inner diameter end 537a of the fluid recovery groove 537 and the area to be sealed (H), the inner diameter end 537a of the fluid recovery groove 537 and the area to be sealed (H) are separated by the remaining land 540, and therefore the fluid recovery groove 537 and the area to be sealed (H) are not connected to each other.

[0091] Next, a seal ring according to a sixth embodiment will be described with reference to Fig. 9. 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.

[0092] 9, a dynamic pressure generating groove 636 and a fluid recovery groove 637 are provided on the right surface 503a of the seal ring 603 of the sixth embodiment. The dynamic pressure generating groove 636 and the fluid recovery groove 637 have the same configurations as the dynamic pressure generating groove 36 and the fluid recovery groove 37 of the first embodiment.

[0093] A land 640 between the inner diameter end 637a of the fluid recovery groove 637 and the area to be sealed (H) on the right surface 603a of the seal ring 603 is provided with a plurality of dimples 610. The plurality of dimples 610 provided between the inner diameter end 637a of the fluid recovery groove 637 and the area to be sealed (H) make it easier to discharge the fluid toward the area to be sealed (H).

[0094] In this way, even if a dimple 610 is provided between the inner diameter end 637a of the fluid recovery groove 637 and the area to be sealed (H), the inner diameter end 637a of the fluid recovery groove 637 and the area to be sealed (H) are separated by the remaining land 640, so the fluid recovery groove 637 and the area to be sealed (H) are not connected to each other.

[0095] In other words, it is only necessary that the fluid recovery groove 637 and the area to be sealed (H) are not in communication with each other via the dimple 610 .

[0096] Next, a seal ring according to a seventh embodiment will be described with reference to Fig. 10. Note that the seal ring has the same configuration as that of the first embodiment, and therefore the description of the same configuration will be omitted.

[0097] As shown in Figure 10, the seal ring 703 of this embodiment 7 is configured so that the right surface 703a, 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.

[0098] This seal ring 703 has a dynamic pressure generating groove 736 and a fluid recovery groove 737 formed on an outer peripheral surface 703b serving as a sliding surface. These dynamic pressure generating groove 736 and fluid recovery groove 737 communicate with a region to be sealed (H) on the outer peripheral surface 703b opposite to the right surface 703a.

[0099] When the seal ring 703 rotates together with the rotating shaft 1, the outer peripheral surface 703b of the seal ring 703 slides against the inner peripheral surface 2a of the housing 2, generating dynamic pressure in the dynamic pressure generating groove 736, causing the outer peripheral surface 703b of the seal ring 703 and the inner peripheral surface 2a of the housing 2 to separate, forming an oil film.

[0100] At this time, the fluid between the outer peripheral surface 703b of the seal ring 703 and the inner peripheral surface 2a of the housing 2 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, and the pressure on the side of the area to be sealed (H) decreases, thereby suppressing the inclination between the outer peripheral surface 703b of the seal ring 703 and the inner peripheral surface 2a of the housing 2.

[0101] Next, a seal ring according to an eighth embodiment will be described with reference to Fig. 11. Note that the seal ring has the same configuration as that of the first embodiment, and therefore the description of the same configuration will be omitted.

[0102] 11, in the shaft seal device of the eighth embodiment, an annular groove 82A is formed in a housing 82, and a seal ring 803 is disposed in the annular groove 82A. The outer peripheral surface 81a of the rotating shaft 81 extends flat in the axial direction.

[0103] An inner peripheral surface 803 d as a mounting surface of the seal ring 803 is pressed against the outer peripheral surface 81 a of the rotary shaft 81 by fluid pressure, and rotates together with the rotary shaft 81 .

[0104] A right surface 803a of the seal ring 803 as a sliding surface comes into contact with the right surface 82a of the annular groove 82A due to fluid pressure, and is capable of sliding relative to the right surface 82a.

[0105] A dynamic pressure generating groove 836 and a fluid recovery groove 837 are formed on the right surface 803a of the seal ring 803. The dynamic pressure generating groove 836 and the fluid recovery groove 837 communicate with the area to be sealed (H) on the right surface 803a opposite the inner circumferential surface 803d.

[0106] When the seal ring 803 rotates together with the rotating shaft 81, the right surface 803a of the seal ring 803 slides against the right surface 82a of the annular groove 82A, generating dynamic pressure in the dynamic pressure generating groove 836, causing the right surface 803a of the seal ring 803 and the right surface 82a of the annular groove 82A to separate, forming an oil film.

[0107] At this time, the fluid between the right surface 803a of the seal ring 803 and the right surface 82a of the annular groove 82A is recovered by the fluid recovery groove 837 on the side of the area to be sealed (H) closer to the dynamic pressure generating groove 836, thereby reducing the pressure on the side of the area to be sealed (H), thereby suppressing the inclination between the right surface 803a of the seal ring 803 and the right surface 82a of the annular groove 82A.

[0108] 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.

[0109] For example, in the first to eighth 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.

[0110] Furthermore, in the above-described Examples 1 to 8, 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.

[0111] Furthermore, in the first, second, fifth and sixth 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.

[0112] Furthermore, in the first to eighth 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.

[0113] Furthermore, while the fluid recovery mechanism in Examples 1 to 8 has a constant depth, the depth may vary. For example, as shown in FIG. 12 , the fluid recovery groove 937 may gradually become shallower from the inner diameter end 937 a to the outer diameter end 937 b. This allows a relative negative pressure to be generated at the outer diameter end 937 b, which is upstream of the relative rotation of the fluid recovery groove 937, making it easier to capture fluid between the sliding surfaces. Furthermore, because the inner diameter end 937 a of the fluid recovery groove 937 is a deep groove, dynamic pressure is less likely to be generated near the inner diameter end 937 a.

[0114] 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) 37a Inner diameter end (end on downstream side of relative rotation) 37b Outer diameter end (end on upstream side of relative rotation) 38 First groove portion (fluid introduction groove) 39 Second groove portion (dynamic pressure generating groove) 39b End (dynamic pressure generating portion) 40 Land 401 Land 402 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 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 provided with a dynamic pressure generating mechanism which communicates with the one space and has a dynamic pressure generating part, and a fluid recovery mechanism which is located between the dynamic pressure generating part and the one space.

2. A seal ring according to claim 1, wherein said fluid recovery mechanism is disposed on a side closer to said one space.

3. The seal ring according to claim 1, wherein the width of the land between said fluid recovery mechanism and said one space is smaller than the width of said fluid recovery mechanism.

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

5. A seal ring according to claim 1, wherein said fluid recovery mechanism is disposed so that an end portion on the downstream side in terms of relative rotation faces said one space side.

6. A seal ring according to claim 1, wherein said fluid recovery mechanism has a depth that decreases from the downstream side in the direction of relative rotation to the upstream side in the direction of relative rotation.

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

8. A seal ring as claimed in any one of claims 1 to 7, wherein the dynamic pressure generating mechanism comprises 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.

9. A seal ring as set forth in claim 8, wherein said dynamic pressure generating groove becomes shallower from the upstream side of the relative rotation to the downstream side of the relative rotation.

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