Seal ring

Abstract

Provided is a seal ring capable of maintaining parallelism between sliding surfaces.　A seal ring 3 has: a sliding surface 3a that rotationally slides relative to one of a shaft 1 and a housing 2 into which the shaft 1 is inserted; and an installation surface 3b that intersects with the sliding surface 3a and is installed on the other one of the shaft 1 and the housing 2. The seal ring serves as a partition between one space H located on the side of the sliding surface 3a opposite to the side intersecting with the installation surface 3b, and an other space L disposed on the intersecting side. The seal ring serves as a partition between the one space H disposed on the side opposite to the installation surface 3b and the other space L disposed on the side of the installation surface 3b. The sliding surface 3a includes: a dynamic pressure generation mechanism 36 that communicates with the one space H and has a dynamic pressure generation part 39b; and a fluid recovery mechanism 37 that is disposed closer to the one space H than the dynamic pressure generation part 39b is, communicates with the relative rotation downstream side of the dynamic pressure generation mechanism 36, and does not communicate with 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 with 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. 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 on the first space side of the dynamic pressure generating unit and communicates with the downstream side of the dynamic pressure generating mechanism in terms of relative rotation but is not in communication with the first space. With this, the pressure on the first space side of the positive pressure generated near the dynamic pressure generating unit of the dynamic pressure generating mechanism is released via the fluid recovery mechanism due to the pressure difference with the first space, thereby suppressing the pressure on the first space side of the sliding surface. Furthermore, because the dynamic pressure generating mechanism is in communication with the fluid recovery mechanism as well as the first space, a sufficient amount of fluid is supplied to the dynamic pressure generating mechanism, thereby reliably generating 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 deeper than the dynamic pressure generating mechanism. This allows a large amount of fluid to be taken in between the sliding surfaces, making it easier to reduce the pressure on one side of the sliding surfaces. Furthermore, it is possible to prevent positive pressure from being generated in the fluid recovery mechanism.

[0010] 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. In this way, since the fluid recovery mechanism is in communication with the fluid inlet groove, which is a deep groove, it is possible to suppress the fluid recovery mechanism from affecting the dynamic pressure generating effect of the dynamic pressure generating part.

[0011] The fluid recovery mechanism may be disposed such 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.

[0012] 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.

[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 as viewed from the axial direction, (b) is an enlarged view of the cut portion as viewed 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 grooves and fluid recovery grooves as viewed from the axial direction in the first embodiment, 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 grooves. (c) is an enlarged view of the dynamic pressure generating grooves and fluid recovery grooves as viewed from the axial direction in the second embodiment of the present invention. (d) is an enlarged view of the dynamic pressure generating grooves and fluid recovery grooves as viewed from the axial direction in the third embodiment of the present invention. (e) is an enlarged view of the dynamic pressure generating grooves and fluid recovery grooves as viewed from the axial direction in the fourth embodiment of the present invention. (f) is an enlarged view of the dynamic pressure generating grooves and fluid recovery grooves as viewed from the axial direction in the fifth embodiment of the present invention. (f) is an enlarged view of the dynamic pressure generating grooves and fluid recovery grooves as viewed from the axial direction in the sixth embodiment of the present invention. (f) 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. (f) 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.

[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 is provided between the end 39b of the second groove portion 39 and the region to be sealed (H). More specifically, the fluid recovery groove 37 extends in an arc shape from the first groove portion 38 toward the downstream side in the rotational direction of the rotating shaft 1. The fluid recovery groove 37 is formed so that its circumferential length is longer than its radial width. Note that the fluid recovery groove 37 is not limited to an arc shape when viewed in the axial direction, and may, for example, extend linearly when viewed in the axial direction.

[0036] The fluid recovery groove 37 and the area to be sealed (H) are separated by the land 40. Furthermore, the fluid recovery groove 37 and the second groove portion 39 are separated by the land 40. In other words, the fluid recovery groove 37 is not in communication with the second groove portion 39 and the area to be sealed (H).

[0037] The fluid recovery groove 37 is disposed radially inward from 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 radially inward side of the right surface 3 a of the seal ring 3, i.e., closer to the area to be sealed (H).

[0038] The land 401, which radially separates 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).

[0039] Furthermore, the land 402 that radially separates the fluid recovery groove 37 and the second groove portion 39 has a radial width L2. In other words, the radial width L2 can be said to be the shortest distance between the fluid recovery groove 37 and the second groove portion 39.

[0040] 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 / 3 of the radial width L2, but this can be freely changed. Preferably, the radial width L1 is approximately 1 / 2 to 1 / 50 of the radial width L2.

[0041] 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 / 3 times the groove width L3, but this can be freely changed. Preferably, the radial width L1 is approximately 1 / 2 to 1 / 20 times the radial width L2.

[0042] 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).

[0043] 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.

[0044] 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 it is even more preferable that the end portion 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, as described above.

[0045] 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.

[0046] On the other hand, the oil in the fluid recovery groove 37 moves from the first groove portion 38 toward the end 37b. Note that because the fluid recovery groove 37 is a deep groove, dynamic pressure is not generated near the end 37b.

[0047] In this way, a flow occurs within the fluid recovery groove 37 from the first groove portion 38 toward the end portion 37b, 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).

[0048] Next, the state of the seal ring 3 when the rotating shaft 1 rotates will be described with reference to FIGS.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Furthermore, since a land 401 exists between the fluid recovery groove 37 and the area to be sealed (H), the fluid in the fluid recovery groove 37 is more easily retained even if the pressure of the fluid in the area to be sealed (H) fluctuates.

[0057] Furthermore, the radial width L1 of the land 401 is smaller than the groove width L3 of the fluid recovery groove 37. This positions the fluid recovery groove 37 closer to the area to be sealed (H), making it easier to discharge oil from the fluid recovery groove 37 to the area to be sealed (H).

[0058] 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.

[0059] Furthermore, the fluid recovery groove 37 is a deep groove, which prevents dynamic pressure from being generated near 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 sealed region (H) side. Furthermore, the fluid can be recovered by the entire fluid recovery groove 37.

[0060] Furthermore, the dynamic pressure generating groove 36 includes a first groove portion 38 and a second groove portion 39, and because 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, thereby enhancing the dynamic pressure generating effect in the second groove portion 39. Furthermore, because the fluid recovery groove 37 is in communication with the first groove portion 38, which is a deep groove, the influence of the fluid recovery groove 37 on the dynamic pressure generating effect in the second groove portion 39 can be suppressed.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The fluid recovery groove 237 has an extended end 237c that bends and extends from an end 237b toward the inner diameter side. A land 240 exists between the extended end 237c and the region to be sealed (H).

[0068] In this way, the extended end portion 237c of the fluid recovery groove 237 downstream of the relative rotation is positioned closer to the sealed area (H) than the upstream side of the relative rotation, and during relative sliding, the fluid flows within the fluid recovery groove 237 from the end portion 237b toward the inner diameter side, making it easier to discharge the fluid toward the sealed area (H).

[0069] Furthermore, since the radial width of the land 240 can be reduced, it becomes easier to discharge the fluid toward the sealed region (H).

[0070] 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.

[0071] 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.

[0072] The fluid recovery groove 337 extends from the first groove portion 338 at an inclination toward the inner diameter side toward the downstream side in the rotation direction of the rotating shaft 1. This fluid recovery groove 337 is formed in an arc shape that is convex toward the outer diameter side when viewed in the axial direction. It should be noted that the fluid recovery groove 337 may also extend linearly.

[0073] Furthermore, a land 340 exists between the end 337b of the fluid recovery groove 337 and the area to be sealed (H).

[0074] In this way, the end 337b of the fluid recovery groove 337 downstream of the relative rotation is positioned closer to the sealed area (H) than the upstream side of the relative rotation, and during relative sliding, fluid flows within the fluid recovery groove 237 from the first groove portion 338 toward the end 337b, making it easier to discharge the fluid toward the sealed area (H).

[0075] Furthermore, since the radial width of the land 340 can be reduced, it becomes easier to discharge the fluid toward the sealed region (H).

[0076] 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 first embodiment, and therefore a description of the configuration that overlaps will be omitted.

[0077] 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.

[0078] The fluid recovery groove 437 becomes gradually shallower from the end 437b side toward the first groove portion 438 side. This allows a relative negative pressure to be generated near the end 437d on the upstream side of the relative rotation of the fluid recovery groove 437, making it easier to take in fluid between the sliding surfaces. In addition, because the end 437b of the fluid recovery groove 437 is a deep groove, dynamic pressure is less likely to be generated near the end 437b.

[0079] In this embodiment, the fluid recovery groove 437 is parallel to the circumferential direction of the right surface 403a, i.e., is arranged along the circumferential direction, but it 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.

[0080] 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.

[0081] 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 this embodiment 5. The dynamic pressure generating groove 536 and the fluid recovery groove 537 have the same configuration as the dynamic pressure generating groove 336 and the fluid recovery groove 337 of the embodiment 3.

[0082] 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).

[0083] 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.

[0084] 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.

[0085] 9, a dynamic pressure generating groove 636 and a fluid recovery groove 637 are provided on a right surface 603a of a seal ring 603 of the sixth embodiment. The dynamic pressure generating groove 636 and the fluid recovery groove 637 have the same configuration as the dynamic pressure generating groove 336 and the fluid recovery groove 337 of the third embodiment.

[0086] 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).

[0087] 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.

[0088] 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 .

[0089] Next, a seal ring according to a seventh embodiment will be described with reference to Fig. 10. Note that the configuration is the same as that of the first embodiment, and therefore a description of the configuration that overlaps will be omitted.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] Next, a seal ring according to an eighth embodiment will be described with reference to Fig. 11. Note that the configuration is the same as that of the first embodiment, and therefore a description of the configuration that overlaps will be omitted.

[0095] 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.

[0096] 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 .

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] Furthermore, in the first to eighth 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.

[0105] 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.

[0106] DESCRIPTION OF SYMBOLS 1 Rotating shaft (shaft) 1A Annular groove 1a Right surface (sliding surface) 2 Housing 2a Inner peripheral surface (sliding surface) 3 Seal ring 3a Right surface (sliding surface) 3b Outer peripheral surface (installation surface) 36 Dynamic pressure generating groove (dynamic pressure generating mechanism) 37 Fluid recovery groove (dynamic pressure generating mechanism) 38 First groove portion (fluid introduction groove) 39 Second groove portion (dynamic pressure generating groove) 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 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 one space side of the dynamic pressure generating part and communicates with the downstream side of the dynamic pressure generating mechanism in relation to the relative rotation but is not communicated with the one space side.

2. The seal ring according to claim 1, wherein said fluid recovery mechanism is deeper than said dynamic pressure generating mechanism.

3. A seal ring as described in claim 1 or 2, 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 in communication with the fluid inlet groove.

4. 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.

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

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