Sealing ring

Abstract

The invention provides a seal ring capable of maintaining parallelism between sliding surfaces. The seal ring (3) is provided with: a sliding surface (3a) provided with a dynamic pressure generation groove (36) that generates dynamic pressure by rotationally sliding relative to one of the shaft (1) and the housing (2) into which the shaft (1) is inserted; an installation surface (3b) that intersects the sliding surface (3a) and is provided on the other of the shaft (1) and the housing (2); the seal ring (3) is provided with a recess (37) on a surface facing the other of the shaft and the housing, the recess opening to the other of the shaft (1) and the housing (2).

Description

Technical Field

[0001] The present invention relates to a sealing ring for shaft sealing the gap between a shaft and a housing, and particularly to a sealing ring used by being installed in an annular groove (so-called stuffing box). Background Art

[0002] As a shaft sealing device for preventing leakage of a fluid to be sealed, for example, there is an annular sealing ring provided between a rotating shaft of a rotating device and a housing. In such a sealing ring, in recent years, due to environmental protection measures and the like, it has been desired to reduce energy loss due to sliding.

[0003] For example, the sealing ring shown in Patent Document 1 is rotatably loosely fitted in an annular groove provided in a rotating shaft while being fixed to the housing, so that the side surface of the sealing ring and the side surface of the annular groove can relatively slide.

[0004] In addition, an oil groove communicating with the oil chamber side is provided on the side surface of the sealing ring, and a wedge effect generating groove extending in the circumferential direction is provided from the oil groove. When the rotating shaft rotates, the oil groove sucks hydraulic oil from the oil chamber, and dynamic pressure is generated by the wedge effect in the wedge effect generating groove, so that the side surface of the sealing ring floats from the side surface of the annular groove to form an oil film. Thereby, the frictional force between the side surface of the sealing ring and the side surface of the annular groove can be reduced. Patent Document

[0005] Patent Document 1: Japanese Patent Laid-Open No. 9-210211 (page 4, Figure 4) Summary of the Invention

[0006] In the sealing ring shown in Patent Document 1, the sealing ring protrudes outward in diameter with respect to the annular groove of the rotating shaft, and the outer diameter side portion of the side surface of the sealing ring is processed so that no dynamic pressure is generated at the wedge effect generating groove. Thus, since dynamic pressure is generated only at the inner diameter side portion in the side surface of the sealing ring, torsional deformation occurs in the sealing ring in such a manner that the inner diameter side portion is separated from the side surface of the annular groove while the outer diameter side portion approaches the side surface of the annular groove, which may reduce the dynamic pressure generation effect.

[0007] The present invention has been completed in view of such problems, and an object thereof is to provide a sealing ring capable of maintaining the parallelism of mutual sliding surfaces.

[0008] In order to solve the above problems, the sealing ring of the present invention is as follows: A sealing ring including: a sliding surface on which a dynamic pressure generating groove is provided, and one of a shaft and a housing into which the shaft is inserted rotates and slides relative to the dynamic pressure generating groove to generate dynamic pressure; and a setting surface that intersects the sliding surface and is provided on the other of the shaft and the housing. In the seal ring, on the surface of the seal ring that faces the shaft and the surface on the other side in the housing, a recess that opens toward the other side of the shaft and the housing is provided. Thereby, the portion between the sliding surface of the seal ring and the recess deforms toward the recess side due to the stress generated when hydrodynamic pressure occurs, and this stress can be absorbed, so the parallelism between the sliding surfaces can be maintained.

[0009] The recess can be provided over the entire circumference of the seal ring. Thereby, the portion between the sliding surface and the recess in the seal ring can deform uniformly over the entire circumference.

[0010] The sliding surface can be separated from the surface to be provided, which is the other of the shaft and the housing, and faces the installation surface. Thereby, since the portion between the sliding surface and the recess in the seal ring does not interfere with the surface to be provided, which is the other of the shaft and the housing, this portion easily deforms toward the recess side.

[0011] The recess can extend at least to the sliding surface of at least one of the shaft and the housing. Thereby, when viewed axially, since the recess extends to a position overlapping the sliding surface, the portion of the seal ring located between the sliding surface and the recess can be reliably deformed toward the recess side.

[0012] The hydrodynamic pressure generating groove can also be provided at a position closer to the side opposite to the shaft and the other in the housing than the bottom surface of the recess. Thereby, since the hydrodynamic pressure generating groove is not formed in the portion of the seal ring located between the sliding surface and the recess, a change in the function of the hydrodynamic pressure generating groove due to the deformation of this portion can be avoided.

[0013] The sliding surface of at least one of the shaft and the housing is axially opposed to the sliding surface, The recess can be provided at a position closer to the sliding surface than the axial center of the seal ring. Thereby, the portion of the seal ring located between the sliding surface and the recess can be configured in a thinner shape, so this portion easily deforms.

[0014] The sliding surface of at least one of the shaft and the housing is radially opposed to the sliding surface, The recess can be provided closer to the sliding surface side. Thereby, the portion of the seal ring located between the sliding surface and the recess can be configured in a thinner shape, so this portion easily deforms.

[0015] The cross-sectional shape of the seal ring can be line-symmetric with respect to the radial line.

[0016] Therefore, when assembling the seal ring, there is no need to pay attention to the orientation of the sliding surface, and the assembly can be carried out simply. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a schematic cross-sectional view showing a shaft seal device to which the seal ring according to Embodiment 1 of the present invention is applied. Figure 2 (a) is a view of the seal ring observed axially, Figure 2 (b) is an enlarged view of the cut-off part observed axially, Figure 2 (c) is a view from the A arrow view. Figure 3 (a) is a view of the hydrodynamic pressure generating groove observed axially, Figure 3 (b) is a sectional view taken along line B-B. Figure 4 It shows along Figure 3 A schematic view of the end face after being cut along the C-C section in. Figure 5 It is a schematic cross-sectional view showing a state where hydrodynamic pressure is generated by the hydrodynamic pressure generating groove. Figure 6 It is a schematic cross-sectional view showing a shaft seal device to which the seal ring according to Embodiment 2 of the present invention is applied. Figure 7 It is a schematic cross-sectional view showing a shaft seal device to which the seal ring according to Embodiment 3 of the present invention is applied. Figure 8 It is a schematic cross-sectional view showing a shaft seal device to which the seal ring according to Embodiment 4 of the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the embodiments of the seal ring according to the present invention will be described based on the embodiments. Embodiment 1

[0018] The seal ring according to Embodiment 1 will be described with reference to Figures 1 to 5 In addition, in this embodiment, the Figure 1 The right side of the paper surface in is referred to as the right side of the seal ring, and the left side of the paper surface is referred to as the left side of the seal ring for description. For convenience of explanation, the hydrodynamic pressure generating grooves 36, 36', grooves 37, 37', protrusions 38, 38', etc. are shown larger than the actual size.

[0019] Figure 1 The shaft seal device shown, for example, in a rotating device, can be suitably used for sealing the annular gap between the relatively rotating rotating shaft 1 and the housing 2 in order to maintain the oil pressure. In this embodiment, the case of being applied to the above-mentioned use will be described as an example. In addition, Figure 1 shows a state where no hydrodynamic pressure is generated in the hydrodynamic pressure generating groove 36 of the seal ring 3.

[0020] The shaft seal device mainly consists of a rotating shaft 1 serving as a shaft, a housing 2, and a sealing ring 3. The sealing ring 3 is loosely fitted in an annular groove 1A with a rectangular cross-section provided on the rotating shaft 1.

[0021] As described below, the right surface 3a of the sealing ring 3 serving as a sliding surface slides on the right surface 1a of the annular groove 1A serving as a surface to be slid, and the outer peripheral surface 3b of the sealing ring 3 serving as a setting surface is pressed against the inner peripheral surface 2a of the housing 2 serving as a surface to be set.

[0022] In addition, the right surface 3a of the sealing ring 3 has a portion in contact with the right surface 1a of the annular groove 1A, and a portion provided on the outer diameter side of the right surface 1a of the annular groove 1A (hereinafter also referred to as "coplanar portion"); in this embodiment, the sliding surface of the sealing ring 3 refers to the entire surface of the right surface 3a of the sealing ring 3. That is, the sliding surface of the sealing ring 3 includes: a portion in contact with the right surface 1a of the annular groove 1A, and a portion coplanar with this portion.

[0023] In this embodiment, it is configured that Figure 1 the fluid pressure in the left region changes, and the sealing ring 3 plays a role in maintaining the fluid pressure in the sealed object region (H) on the left side in the figure. In addition, although not shown, in the state where the equipment using the sealing ring 3 stops, the fluid pressure in the sealed object region (H) is low, and is the same as Figure 1 the pressure in the right leakage region (L), and in the state where the equipment is operating, the fluid pressure in the sealed object region (H) is higher than that in the leakage region (L).

[0024] The sealing ring 3 is made of resin materials such as polyether ether ketone (PEEK), polyphenylene sulfide (PPS), and polytetrafluoroethylene (PTFE).

[0025] As Figure 2 shown in (a) to (c), the sealing ring 3 is formed with a cut portion 31 at one place in the circumferential direction. In addition, Figure 2 (b) is Figure 2 an enlarged view of the circled portion in (a).

[0026] The cut portion 31 is in a known special stepped cut shape that is stepped when viewed from both axial sides (refer to Figure 2 (a), (b)) and the outer diameter side (refer to Figure 2 (c)). Thus, in the sealing ring 3, a first fitting convex portion 32 and a first fitting concave portion 33 are provided on the outer peripheral surface side of one side, and a second fitting concave portion 34 for fitting the first fitting convex portion 32 and a second fitting convex portion 35 for fitting the first fitting concave portion 33 are provided on the outer peripheral surface side of the other side.

[0027] In addition, the cutting portion 31 includes not only the case of cutting by machining, but also the case of being formed by molding. In addition, here, as an example of the cutting portion 31, although the case of a special stepped notch is shown, it is not limited thereto, and known straight notches, inclined notches, ordinary stepped notches, etc. can also be used. In addition, when the material of the sealing ring 3 is a low-elasticity material (such as PTFE, etc.), the cutting portion may not be provided.

[0028] In addition, as Figure 2 (a) and Figure 3 (a), (b) show, on the right surface 3a of the sealing ring 3, a plurality of hydrodynamic pressure generating grooves 36 are formed in the circumferential direction. In addition, the number of the hydrodynamic pressure generating grooves 36 can be freely changed.

[0029] Especially as Figure 3 (a) shows, the hydrodynamic pressure generating groove 36 has a rectangular shape extending in the circumferential direction in the axial view. The hydrodynamic pressure generating groove 36 opens toward the axial direction and the inner diameter direction. In addition, between the circumferentially adjacent hydrodynamic pressure generating grooves 36, they are separated by the boss 39 constituting the right surface 3a of the sealing ring 3.

[0030] In addition, the hydrodynamic pressure generating groove 36 includes an inlet groove portion 361 and an inclined groove portion 362.

[0031] Especially as Figure 3 (b) shows, the inlet groove portion 361 is provided on the upstream side in the rotation direction of the hydrodynamic pressure generating groove 36 (that is, Figure 3 the left side of the paper surface in (b)). The inlet groove portion 361 can store the oil on the inner diameter side of the sealing ring 3.

[0032] The inclined groove portion 362 is configured to gradually become shallower from the inlet groove portion 361 toward the downstream side in the rotation direction (that is, Figure 3 the right side of the paper surface in (b)). Specifically, the bottom surface 362a of the inclined groove portion 362 extends linearly from near the bottom of the inlet groove portion 361 to the boss 39.

[0033] When the right surface 3a of the sealing ring 3 slides relative to the right surface 1a of the rotating shaft 1, the oil in the inlet groove portion 361 is introduced into the inclined groove portion 362, and hydrodynamic pressure is generated due to the wedge effect of the inclined groove portion 362. As a result, the right surface 3a of the sealing ring 3 is slightly separated from the right surface 1a of the rotating shaft 1 (refer to Figure 5 ), and at the same time, an oil film is formed, so the frictional force between the right surface 3a of the sealing ring 3 and the right surface 1a of the annular groove 1A can be reduced.

[0034] As Figure 4 shown, the cross-sectional shape of the portion of the sealing ring 3 other than the cutting portion 31 is line-symmetric with respect to the radial line α.

[0035] Specifically, the seal ring 3 is provided with dynamic pressure generating grooves 36, 36', as well as grooves 37, 37' serving as recesses and protrusions 38, 38'.

[0036] The dynamic pressure generating groove 36' has a symmetrical shape with respect to the above-mentioned dynamic pressure generating groove 36.

[0037] The groove 37 is provided at a position leaving from the right surface 3a of the seal ring 3 toward the left side. That is, the groove 37 is provided on the back of the right surface 3a. In other words, the groove 37 is provided at a position axially overlapping with the right surface 3a. The groove 37 has a rectangular cross-sectional shape opening toward the outer diameter side and is provided over the entire circumference of the seal ring 3. In addition, the groove 37 opens at both circumferential ends.

[0038] In addition, the groove 37 extends to a position more on the inner diameter side than the outer diameter end of the right surface 1a of the annular groove 1A. In other words, the groove 37 axially overlaps with the right surface 1a of the annular groove 1A (see Figure 1 ).

[0039] The groove 37' is provided at a position leaving from the left surface 3c of the seal ring 3 toward the right side on the outer peripheral surface 3b of the seal ring 3. The groove 37' has a symmetrical shape with respect to the groove 37.

[0040] The protrusion 38 is a portion that is more on the outer diameter side than the bottom surface 37a of the groove 37 and protrudes. In other words, the protrusion 38 is a portion remaining between the groove 37 and the right surface 3a of the seal ring 3 and can also be called a corner portion. In addition, the right surface of the protrusion 38 constitutes a part of the right surface 3a of the seal ring 3.

[0041] The outer peripheral surface 38a of the protrusion 38 is provided at a position more on the inner diameter side than the outer peripheral surface 3b of the seal ring 3. In other words, the protrusion 38 is radially separated from the inner peripheral surface 2a of the housing 2.

[0042] The protrusion 38' is a portion remaining between the groove 37' and the left surface 3c of the seal ring 3 and can also be called a corner portion. The protrusion 38' has a symmetrical shape with respect to the protrusion 38.

[0043] The dynamic pressure generating grooves 36, 36' are provided at positions more on the inner diameter side than the bottom surfaces 37a, 37a' of the grooves 37, 37'. In other words, the dynamic pressure generating grooves 36, 36' do not axially overlap with the grooves 37, 37'. That is, the dynamic pressure generating grooves 36, 36' are not provided on the protrusions 38, 38'.

[0044] Next, the state of the seal ring during rotation of the rotating shaft 1 will be described using Figure 5 .

[0045] As Figure 1As shown, when the device is started, the fluid pressure in the area (H) to be sealed is higher than that in the leakage area (L). Due to the fluid pressure in the area (H) to be sealed, a force in the direction of expanding the diameter acts on the sealing ring 3, and the outer peripheral surface 3b of the sealing ring 3 is pressed against the inner peripheral surface 2a of the housing 2. That is, the sealing ring 3 is fixed to the housing 2.

[0046] In addition, due to the fluid pressure in the area (H) to be sealed, the right surface 3a of the sealing ring 3 is pressed against the right surface 1a of the annular groove 1A on the rotating shaft 1 and slides.

[0047] As Figure 5 shown, when the right surface 3a of the sealing ring 3 slides relative to the right surface 1a of the rotating shaft 1, hydrodynamic pressure is generated by the hydrodynamic pressure generating groove 36, and the right surface 3a of the sealing ring 3 is slightly separated from the right surface 1a of the annular groove 1A. In addition, in Figure 5 for ease of explanation, the separation width between the right surface 3a of the sealing ring 3 and the right surface 1a of the annular groove 1A is shown larger than the actual value.

[0048] At this time, since the hydrodynamic pressure generating groove 36 is not provided on the outer diameter side of the right surface 3a of the sealing ring 3, a greater hydrodynamic pressure acts on the inner diameter side than on the outer diameter side of the right surface 3a of the sealing ring 3. That is, a torsional force acts on the sealing ring 3, causing the inner diameter side of the right surface 3a of the sealing ring 3 to separate from the right surface 1a of the annular groove 1A more than the outer diameter side.

[0049] Specifically, a force acts on the sealing ring 3 to tilt the right surface 3a of the sealing ring 3 relative to the right surface 1a of the annular groove 1A, causing the portion of the sealing ring 3 closer to the inner diameter side than the center point P of its cross-section to separate from the right surface 1a of the annular groove 1A, while the portion closer to the outer diameter side than the center point P approaches the right surface 1a of the annular groove 1A.

[0050] Since the sealing ring 3 of the present Embodiment 1 is provided with the groove 37, when hydrodynamic pressure is generated between the right surface 3a of the sealing ring 3 and the right surface 1a of the annular groove 1A, the convex portion 38 can be deformed toward the groove 37 by the stress generated thereby, and the stress can be absorbed. Accordingly, the sealing ring 3 hardly deforms in the torsional direction, and the right surface 3a of the sealing ring 3 hardly tilts relative to the right surface 1a of the annular groove 1A. Therefore, the parallelism between the right surface 3a of the sealing ring 3 and the right surface 1a of the annular groove 1A can be maintained. Therefore, contact between the right surface 3a of the sealing ring 3 and the right surface 1a of the annular groove 1A can be avoided, and a reduction in the hydrodynamic pressure effect caused by the hydrodynamic pressure generating groove 36 can be prevented.

[0051] In addition, even if the left and right widths of the groove 37 are narrow, the convex portion 38 can be significantly deformed toward the groove 37, thereby ensuring that the outer peripheral surface 3b of the sealing ring 3 has sufficient left and right widths, enabling the sealing ring 3 to be stably mounted on the housing 2. In other words, synchronization rotation of the sealing ring 3 with the rotating shaft 1 can be prevented.

[0052] In addition, since the groove 37 is provided over the entire circumference of the seal ring 3, the convex portion 38 can be uniformly deformed circumferentially. Further, even if the groove 37 is divided by the cut portion 31 as in the present embodiment, it still forms an annular groove provided over the entire circumference.

[0053] In addition, since the outer peripheral surface 38a of the convex portion 38 is provided at a position closer to the inner diameter side than the outer peripheral surface 3b of the seal ring 3, when the convex portion 38 deforms toward the groove 37, the outer peripheral surface 38a of the convex portion 38 does not interfere with the inner peripheral surface 2a of the housing 2. Therefore, the convex portion 38 can deform smoothly.

[0054] In addition, since the groove 37 extends to a position closer to the inner diameter side than the outer diameter end of the right surface 1a of the annular groove 1A, the convex portion 38 can be reliably deformed toward the groove 37. Moreover, it is possible to ensure that the deformation of the convex portion 38 effectively contributes to maintaining the parallelism between the right surface 3a of the seal ring 3 and the right surface 1a of the annular groove 1A.

[0055] In addition, the hydrodynamic pressure generating groove 36 is provided at a position closer to the inner diameter side than the bottom surface 37a of the groove 37. Thus, since the hydrodynamic pressure generating groove 36 is not provided in the convex portion 38, even if the convex portion 38 deforms, it does not affect the effect of generating hydrodynamic pressure in the hydrodynamic pressure generating groove 36.

[0056] In addition, since the groove 37 is provided at a position on the seal ring 3 closer to the right surface 3a side than the axial center. Thus, the axial thickness of the convex portion 38 can be designed to be thin, so that it can be easily deformed even under a small hydrodynamic pressure.

[0057] In addition, since the cross-sectional shape of the seal ring 3 is linearly symmetric with respect to the radial line α, it is not necessary to consider the axial orientation of the seal ring 3 when assembling the seal ring 3, thereby making the assembly process simpler.

[0058] In addition, for example, when used in a shaft seal device in which the pressure balance is reversed in the regions on both sides of the seal ring 3, while generating hydrodynamic pressure using one of the hydrodynamic pressure generating grooves 36, 36', one of the convex portions 38, 38' can be deformed. Specifically, taking Figure 1 the case where the pressure balance in the regions on both sides is reversed as an example, the seal ring 3 moves to the left, and its left surface 3c contacts and slides on the left surface 1b of the annular groove 1A, so that while generating hydrodynamic pressure using the hydrodynamic pressure generating groove 36', the convex portion 38' is deformed. Embodiment 2

[0059] Next, a description will be given of the seal ring according to Embodiment 2 with reference to Figure 6 In addition, the description of the parts having the same configuration as in Embodiment 1 will be omitted.

[0060] As Figure 6As shown, the sealing ring 203 of the second embodiment does not have hydrodynamic pressure generating grooves 36', 37' and protrusion 38' on the left side. In other words, the sealing ring 203 of the second embodiment only has hydrodynamic pressure generating grooves 236, 237 and protrusion 238 on the right side. Embodiment 3

[0061] Next, refer to Figure 7 the sealing ring involved in Embodiment 3 will be described. In addition, the same structural parts as in Embodiment 2 will not be described again.

[0062] As Figure 7 shown, under the action of fluid pressure, the right surface 303a of the sealing ring 303 of the third embodiment, which is its setting surface, is pressed against the right surface 1a of the annular groove 1A on the rotating shaft 1 and rotates together with the rotating shaft 1.

[0063] The sealing ring 303 has a hydrodynamic pressure generating groove 336 formed on its outer peripheral surface 303b which is a sliding surface. In addition, a groove 337 is provided at a position separated from the outer peripheral surface 303b of the sealing ring 303 toward the inner diameter side. The groove 337 has a rectangular cross-section opening to the right and is provided over the entire circumference of the sealing ring 303. In addition, in the cross-section of the sealing ring 303, the groove 337 is provided near the radially outer side, that is, near the outer peripheral surface 303b side.

[0064] In addition, the protrusion 338 remaining between the groove 337 and the outer peripheral surface 303b is in a state of being separated to the left from the right surface 1a of the annular groove 1A.

[0065] When the sealing ring 303 rotates together with the rotating shaft 1, the outer peripheral surface 303b of the sealing ring 303 slides on the inner peripheral surface 2a of the housing 2, hydrodynamic pressure is generated in the hydrodynamic pressure generating groove 336, and the outer peripheral surface 303b of the sealing ring 303 is separated from the inner peripheral surface 2a of the housing 2, thereby forming an oil film.

[0066] At this time, due to the hydrodynamic pressure generated by the hydrodynamic pressure generating groove 336, the protrusion 338 deforms toward the inner diameter side, thereby being able to suppress the generation of inclination between the outer peripheral surface 303b of the sealing ring 303 and the inner peripheral surface 2a of the housing 2.

[0067] In addition, since the groove 337 is provided near the outer peripheral surface 303b side, the thickness of the protrusion 338 in the radial direction can be designed to be thinner, so it is easy to deform even under a small hydrodynamic pressure. Embodiment 4

[0068] Next, refer to Figure 8 the sealing ring involved in Embodiment 4 will be described. In addition, the same structural parts as in the above Embodiment 3 will not be described again.

[0069] As Figure 8As shown, the shaft seal device of the fourth embodiment has an annular groove 42A provided in the housing 42, and the sealing ring 403 is installed in the annular groove 42A. In addition, the outer peripheral surface 41a of the rotating shaft 41 extends axially flatly.

[0070] The inner peripheral surface 403d of the sealing ring 403, which serves as the setting surface, is pressed against the outer peripheral surface 41a of the rotating shaft 41 under the action of fluid pressure and rotates together with the rotating shaft 41.

[0071] In addition, the right surface 403a of the sealing ring 403, which serves as the sliding surface, contacts the right surface 42a of the annular groove 42A under the action of fluid pressure and can slide relative to the right surface 42a.

[0072] A hydrodynamic pressure generating groove 436 is formed on the right surface 403a of the sealing ring 403. In addition, a groove 437 is provided at a position of the sealing ring 403 separated from the right surface 403a toward the left side. The groove 437 has a rectangular cross-section opening toward the inner diameter side and is provided over the entire circumference of the sealing ring 403.

[0073] In addition, the convex portion 438 remaining between the groove 437 and the right surface 403a is separated from the outer peripheral surface 41a of the rotating shaft 41 toward the outer diameter side.

[0074] When the sealing ring 403 rotates together with the rotating shaft 41, the right surface 403a of the sealing ring 403 slides on the right surface 42a of the annular groove 42A, hydrodynamic pressure is generated in the hydrodynamic pressure generating groove 436, and the right surface 403a of the sealing ring 403 is separated from the right surface 42a of the annular groove 42A, thereby forming an oil film.

[0075] At this time, due to the hydrodynamic pressure generated by the hydrodynamic pressure generating groove 436, the convex portion 438 deforms toward the groove 437 side, thereby being able to suppress the generation of inclination between the right surface 403a of the sealing ring 403 and the right surface 42a of the annular groove 42A.

[0076] The embodiments of the present invention have been described above with reference to the drawings, but the specific structure of the present invention is not limited to the above embodiments, and any changes or additions made without departing from the gist of the present invention should be included in the present invention.

[0077] For example, in the above-described first to fourth embodiments, the form in which the sliding surface and the setting surface of the sealing ring are orthogonal to each other is taken as an example for description, but as long as the sliding surface and the setting surface extend in the intersecting direction, it is not limited to the orthogonal state.

[0078] In addition, in the above-described first to fourth embodiments, the hydrodynamic pressure generating groove is taken as an example of a rectangular groove opening to the sealing target area side and the opposite sliding surface side. However, for example, it may also be a pit opening only to the opposite sliding surface, or a spiral groove having circumferential and radial extension components, etc., and its shape can be freely changed. In addition, the number of hydrodynamic pressure generating grooves can also be freely adjusted.

[0079] In addition, in the above-described Embodiments 1 to 4, the form in which the recess extends over the entire circumference of the seal ring has been described as an example. However, for example, a plurality of recesses may be provided independently in the circumferential direction.

[0080] In addition, the circumferential end of the recess may not be provided to open toward the cut portion 31.

[0081] In addition, in the above-described Embodiments 1 to 4, the cross-section of the recess has been described as having a rectangular shape as an example. However, the cross-section may have other forms such as a U-shape or a V-shape.

[0082] In addition, in the above-described Embodiments 1 to 4, the form in which the convex portion is separated from the surface to be provided on the shaft or the housing has been illustrated. However, the convex portion may be in contact with the surface to be provided.

[0083] In addition, in the above-described Embodiments 1 to 4, the form in which no hydrodynamic pressure generating groove is provided in the convex portion has been illustrated. However, for example, a part of the hydrodynamic pressure generating groove may be provided in the convex portion.

[0084] In addition, as long as the convex portion can be deformed, its thickness and width can be freely adjusted.

[0085] In the above-described Embodiments 1 to 4, the form in which the shaft rotates relative to the housing has been illustrated. However, the housing may rotate relative to the shaft, or both the shaft and the housing may rotate in the relative rotation direction. Description of Reference Numerals

[0086] 1 Rotating shaft (shaft); 1A Annular groove; 1a Right surface (surface to be slid); 2 Housing; 2a Inner circumferential surface (surface to be provided); 3 Seal ring; 3a Right surface (sliding surface); 3b Outer circumferential surface (setting surface); 36, 36' Hydrodynamic pressure generating grooves; 37, 37' Grooves (recesses); 38, 38' Convex portions; α Radial line.

Claims

1. A sealing ring, characterized in that, Comprising: A sliding surface, on which a dynamic pressure generating groove is provided, and one of a shaft and a housing into which the shaft is inserted rotates and slides relative to the dynamic pressure generating groove to generate dynamic pressure; A setting surface, which intersects the sliding surface and is provided on the other of the shaft and the housing; In the seal ring, a recess is provided on a surface of the seal ring that faces the surface on the other side of the shaft and the housing, and the recess opens toward the other side of the shaft and the housing.

2. The sealing ring according to claim 1, wherein The recess is provided over the entire circumference of the seal ring.

3. The sealing ring according to claim 1, characterized in that, The sliding surface is separated from a surface to be provided, which is provided on the other of the shaft and the housing and faces the setting surface.

4. The seal ring according to any one of claims 1 to 3, characterized in that, The recess extends at least to a surface to be slid, which is one of the shaft and the housing.

5. The sealing ring according to claim 1, characterized in that, The dynamic pressure generating groove is arranged at a position closer to the side opposite to the other of the shaft and the housing than the bottom surface of the recess.

6. The sealing ring according to claim 1, characterized in that, The surface to be slid, which is one of the shaft and the housing, is axially opposed to the sliding surface. The recess is arranged at a position closer to the sliding surface than the axial center of the seal ring.

7. The sealing ring according to claim 1, characterized in that, The surface to be slid, which is one of the shaft and the housing, is radially opposed to the sliding surface. The recess is arranged closer to the sliding surface side.

8. The sealing ring according to claim 1, wherein, The cross-sectional shape of the seal ring is line-symmetric with respect to a radial line.

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