Sliding member

Abstract

Provided is a sliding member capable of improving lubricity. A sliding member (10, 20) in which a pair of sliding surfaces (11, 21) of the sliding member (10, 20) rotate relative to each other, the sliding member (10, 20) demarcating a space (S1) for fluid to be sealed and a leakage space (S2), the sliding surface (11) being provided with a dynamic pressure generating groove (13) and a fluid recovery groove (12), and the fluid recovery groove (12) being provided in the sliding surface (11). The fluid recovery groove (12) is provided with a pressure generation part (17) which is a circumferential end part, a bent part or a bent part on the downstream side of the relative rotation direction, and the fluid recovery groove (12) is provided with a first groove part (15) which overlaps with the dynamic pressure generation groove (13) in the radial direction at a position closer to the leakage space (S2) side than the dynamic pressure generation groove (13), and a second groove part (15) which overlaps with the first groove part (15) in the radial direction at a position closer to the leakage space (S2) side than the dynamic pressure generation groove (13). And a second groove section (16) that overlaps the dynamic pressure generating groove (13) in the circumferential direction at a position downstream of the dynamic pressure generating groove (13) in relative rotation.

Description

Technical Field

[0001] The present invention relates to sliding members that rotate relative to each other. For example, it relates to sliding members used in a shaft seal device for shaft-sealing a rotating shaft of a rotating machine in the fields of automobiles, general industrial machinery, or other sealing fields, or sliding members used in bearings of machines in the fields of automobiles, general industrial machinery, or other bearing fields. Background Art

[0002] As a shaft seal device for preventing leakage of a fluid to be sealed, for example, a mechanical seal has a pair of annular sliding members that rotate relative to each other and whose sliding surfaces slide on each other. In such a mechanical seal, in recent years, in order to address environmental concerns and the like, it has been desired to reduce the energy lost due to sliding.

[0003] For example, in the mechanical seal shown in Patent Document 1, a plurality of pits are provided in the circumferential direction on the sliding surface of the stationary seal ring. The pits are formed in a crank shape having a cavitation formation region and a positive pressure generation region. The cavitation formation region is arranged on the low-pressure fluid side and is formed in a groove shape extending in the circumferential direction. The positive pressure generation region is arranged on the high-pressure fluid side and is formed in a groove shape extending in the circumferential direction. Moreover, the downstream end in the rotation direction of the cavitation formation region communicates with the upstream end in the rotation direction of the positive pressure generation region.

[0004] As the rotating seal ring rotates, the pits guide the fluid to be sealed from the upstream side in the rotation direction of the cavitation formation region to the downstream side in the rotation direction of the positive pressure generation region, and a positive pressure is generated at its downstream end. By means of this positive pressure, the opposing sliding surface is lifted, and the fluid to be sealed is introduced between the sliding surfaces. Therefore, the energy lost due to sliding can be reduced. Moreover, by means of the negative pressure generated at the upstream end in the rotation direction of the cavitation formation region, the recess can recover the fluid to be sealed that has moved to the low-pressure space side.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent No. 6058018 (pages 7 and 8, Figure 4 ) Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] In the sliding member of Patent Document 1 as described above, the positive pressure generation region of the pits is arranged close to the fluid space to be sealed. Therefore, a part of the fluid to be sealed can be recovered to the high-pressure fluid side. However, the positive pressure generation regions of the pits are arranged to be scattered in the circumferential direction. As a result, the positive pressure generated between the sliding surfaces becomes uneven in the circumferential direction, and it is difficult to achieve a floating balance. Therefore, the lubricity may be impaired.

[0010] The present invention has been completed in view of such problems, and an object thereof is to provide a sliding member capable of improving lubricity.

[0011] Means for Solving the Problem

[0012] In order to solve the above problems, a pair of sliding surfaces of the sliding member of the present invention rotate relative to each other, and the sliding member divides between a sealed fluid space and a leakage space. Among them, a hydrodynamic pressure generating groove and a fluid recovery groove are provided on at least any one of the sliding surfaces. The fluid recovery groove has a pressure generating portion that is a circumferential end portion, a bent portion, or a folded portion on the downstream side in the relative rotation direction. The fluid recovery groove has: a first groove portion that overlaps the hydrodynamic pressure generating groove in the radial direction at a position closer to the leakage space than the hydrodynamic pressure generating groove; and a second groove portion that overlaps the hydrodynamic pressure generating groove in the circumferential direction at a position closer to the downstream side of the relative rotation than the hydrodynamic pressure generating groove.

[0013] Thus, in addition to being able to generate a positive pressure in the hydrodynamic pressure generating groove, a positive pressure can also be generated in the fluid recovery groove. Therefore, a greater hydrodynamic pressure can be generated. The first groove portion of the fluid recovery groove is used to recover the sealed fluid that flows out of the hydrodynamic pressure generating groove and wants to flow to the leakage side, and the downstream second groove portion is used to recover the excess sealed fluid on the sliding surface that causes leakage and return it to the sealed fluid side. Thereby, leakage can be suppressed, and a hydrodynamic pressure can also be generated in the fluid recovery groove. By generating positive pressures at multiple locations using the hydrodynamic pressure generating groove and the fluid recovery groove, the floating balance between the sliding members can be improved, and thereby the lubricity can also be improved.

[0014] Alternatively, the pressure generating portion is a bent portion between the first groove portion and the second groove portion that bends or folds from the first groove portion and extends radially toward the sealed fluid space side.

[0015] Thus, a positive pressure can be generated at the bent portion between the first groove portion and the second groove portion, and the fluid in the fluid recovery groove can be guided toward the sealed fluid space side.

[0016] Alternatively, the fluid recovery groove overlaps with a plurality of the hydrodynamic pressure generating grooves in the radial direction.

[0017] Thus, positive pressures can be reliably generated at multiple locations. And leakage of the sealed fluid to the leakage side can be more reliably prevented.

[0018] Alternatively, the second groove portion inclines from the sealed fluid space toward the leakage space in a direction opposite to the hydrodynamic pressure generating groove.

[0019] Thus, the second groove portion can guide the sealed fluid toward the sealed fluid space side. Thereby, the fluid recovery groove can contribute to preventing leakage.

[0020] Alternatively, the upstream end of the first groove portion of the fluid recovery groove may overlap circumferentially with the bent portion of the fluid recovery groove adjacent on the upstream side of the relative rotation.

[0021] Thus, the fluid recovery groove can efficiently recover the sealed fluid flowing out between the sliding surfaces from the pressure generating portion of the fluid recovery groove adjacent on the upstream side of the relative rotation.

[0022] Alternatively, the adjacent first groove portions may be arranged on the same circumference.

[0023] Thus, the first groove portion can guide the sealed fluid in the rotational direction. Also, the sealed fluid flowing out between the sliding surfaces from the pressure generating portion of the fluid recovery groove adjacent on the upstream side of the relative rotation is also likely to move in the rotational direction. Thus, the sliding member can recover the sealed fluid without omission.

[0024] Alternatively, the first groove portion of the fluid recovery groove may overlap radially with the second groove portion of the fluid recovery groove adjacent on the upstream side of the relative rotation, and the hydrodynamic pressure generating groove is surrounded by the fluid recovery groove and the second groove portion of the fluid recovery groove adjacent on the upstream side of the relative rotation.

[0025] Thus, in addition to improving the floating balance between the sliding members, it is also possible to recover the sealed fluid flowing out between the sliding surfaces from each hydrodynamic pressure generating groove or the pressure generating portion of each fluid recovery groove, reliably preventing radial leakage. Moreover, the sealed fluid recovered by the fluid recovery groove can be discharged to the sealed fluid space from multiple locations in the circumferential direction. Therefore, not only can the deterioration of the sealed fluid staying between the sliding surfaces be suppressed, but also the accumulation of contaminants and the like can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a longitudinal sectional view showing an example of a mechanical seal according to Embodiment 1 of the present invention.

[0027] Figure 2 is a view of the sliding surface of the stationary seal ring of Embodiment 1 as observed axially.

[0028] Figure 3 is Figure 2 a partial enlarged view of

[0029] Figure 4 is an enlarged view of a modified example of the sliding surface of the stationary seal ring of Embodiment 1 as observed axially.

[0030] Figure 5 is an enlarged view of another modified example of the sliding surface of the stationary seal ring of Embodiment 1 as observed axially.

[0031] Figure 6It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 2 of the present invention observed axially.

[0032] Figure 7 It is an enlarged view of a modified example of the sliding surface of the stationary seal ring of Embodiment 2 observed axially.

[0033] Figure 8 It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 3 of the present invention observed axially.

[0034] Figure 9 It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 4 of the present invention observed axially.

[0035] Figure 10 It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 5 of the present invention observed axially.

[0036] Figure 11 It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 6 of the present invention observed axially.

[0037] Figure 12 It is an enlarged view of a modified example of the sliding surface of the stationary seal ring of Embodiment 6 observed axially.

[0038] Figure 13 It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 7 of the present invention observed axially.

[0039] Figure 14 It is a view of the sliding surface of the stationary seal ring of Embodiment 8 of the present invention observed axially.

[0040] Figure 15 It is a view of the sliding surface of the stationary seal ring of Embodiment 9 of the present invention observed axially.

[0041] Figure 16 It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 10 of the present invention observed axially.

[0042] Figure 17 It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 11 of the present invention observed axially.

[0043] Figure 18 It is a view of the sliding surface of the stationary seal ring of Embodiment 12 of the present invention observed axially.

[0044] Figure 19 It is an enlarged view of the sliding surface of the stationary seal ring of Embodiment 13 of the present invention observed axially. Detailed implementation manners

[0045] Hereinafter, a manner for implementing the sliding member of the present invention will be described based on embodiments.

[0046] Example 1

[0047] Reference Figures 1 to 5 The sliding member of Example 1 will be described. In addition, in this example, the case where the sliding member is applied to a mechanical seal will be described as an example.

[0048] Moreover, in the inner space S1 of the mechanical seal, there is a sealed fluid F as the first fluid, and in the outer space S2, there is the atmosphere A as the second fluid. The inner diameter side of the sliding member constituting the mechanical seal is the sealed fluid space side (high pressure side), and the outer diameter side is the leakage space side (low pressure side) for description. And for the sake of convenience in explanation, in the drawings, sometimes points are also marked on the grooves formed on the sliding surface.

[0049] Figure 1 The shown mechanical seal is an outer type mechanical seal that seals the sealed fluid F that wants to leak from the inner diameter side to the outer diameter side of the sliding surface and the outer space S2 communicates with the atmosphere A. In addition, in this example, the case where the sealed fluid F is a high-pressure liquid and the atmosphere A is a gas with a lower pressure than the sealed fluid F is exemplified.

[0050] The mechanical seal mainly consists of an annular stationary seal ring 10 as a sliding member and an annular rotating seal ring 20 as another sliding member. The rotating seal ring 20 is provided on the rotating shaft 1 via a sleeve 2 in a state capable of rotating together with the rotating shaft 1. The stationary seal ring 10 is provided on the seal cover 5 in a non-rotating state and capable of moving axially, and the seal cover 5 is fixed to the housing 4 of the installed equipment. The stationary seal ring 10 is axially biased by an elastic member 7, and the sliding surface 11 of the stationary seal ring 10 and the sliding surface 21 of the rotating seal ring 20 slide while being in close contact with each other. In addition, the sliding surface 21 of the rotating seal ring 20 is a flat surface, and no concave portions such as grooves are provided on this flat surface.

[0051] The stationary seal ring 10 and the rotating seal ring 20 are typically formed by a combination of SiC (hard material) and SiC (hard material) or a combination of SiC (hard material) and carbon (soft material), but are not limited thereto. Any sliding material can be used as long as it can be used as a sliding material for mechanical seals. In addition, as SiC, there are materials composed of two or more phases with different compositions, such as sintered bodies with boron, aluminum, carbon, etc. as sintering aids. For example, SiC dispersed with graphite particles, reaction-sintered SiC composed of SiC and Si, SiC-TiC, SiC-TiN, etc. As carbon, resin-molded carbon, sintered carbon, etc., which are represented by carbon mixed with carbonaceous and graphite materials, can be used. And in addition to the above sliding materials, metal materials, resin materials, surface-modified materials (coating materials), composite materials, etc. can also be used.

[0052] As Figure 2 and Figure 3 shown, relative to the stationary seal ring 10, the rotating seal ring 20 as the opposing side seal ring slides counterclockwise relative to the stationary seal ring 10 as indicated by the solid arrow.

[0053] On the sliding surface 11 of the stationary seal ring 10, a plurality of pumping grooves 12 (12 in this embodiment) serving as fluid recovery grooves and a plurality of dynamic pressure grooves 13 (12 groups of 4 in this embodiment) serving as dynamic pressure generation grooves are formed. And, the portion of the sliding surface 11 other than the pumping grooves 12 and the dynamic pressure grooves 13 is a land portion 14 forming a flat surface.

[0054] The pumping groove 12 is a groove having a substantially L shape with an obtuse inner angle and a substantially constant depth. The pumping groove 12 has a circumferential groove 15 as a first groove portion and an inclined groove 16 as a second groove portion. In addition, the cross-sectional shape of the pumping groove 12 is a rectangular shape, but it may also be a U shape, a semicircular shape, or a triangular shape, and can be appropriately changed. The same applies to the dynamic pressure groove 13.

[0055] More specifically, as Figure 3 shown, the circumferential groove 15 is inclined toward the inner diameter side from the upstream side in the rotation direction of the rotating seal ring 20 to the downstream side in the rotation direction, that is, from the upstream side to the downstream side in the relative rotation direction, and extends in an arc shape in the circumferential direction. The circumferential component of the circumferential groove 15 is larger than the radial component. In addition, the circumferential groove 15 only needs to have at least a circumferential component. That is, the circumferential direction in the present invention means that as long as it includes at least a circumferential component.

[0056] And, the groove width of the circumferential groove 15 gradually expands from the upstream side in the rotation direction of the rotating seal ring 20 to the downstream side in the rotation direction. The end 12c of the circumferential groove 15 on the upstream side in the rotation direction of the rotating seal ring 20 is closed. The end of the circumferential groove 15 on the downstream side in the rotation direction of the rotating seal ring 20 communicates with the inclined groove 16.

[0057] The inclined groove 16 is inclined from the end of the circumferential groove 15 on the downstream side in the rotation direction of the rotating seal ring 20 to the downstream side in the rotation direction of the rotating seal ring 20 and extends substantially linearly toward the inner diameter side. In other words, the inclined groove 16 is inclined in a direction opposite to the dynamic pressure groove 13. The radial component of the inclined groove 16 is larger than the circumferential component. In addition, the inclined groove 16 only needs to have at least a radial component. That is, the radial direction in the present invention means that as long as it includes at least a radial component. And, the circumferential component of the inclined groove 16 is smaller than the circumferential component of the circumferential groove 15, and the radial component of the inclined groove 16 is larger than the radial component of the circumferential groove 15.

[0058] In other words, the inclined groove 16 bends from the circumferential groove 15 at an obtuse angle and extends toward the inner space S1. Moreover, the inner diameter end 16a of the inclined groove 16 communicates with the inner space S1. A bent portion 17 having a bent shape as a pressure generating portion is formed at the connecting portion between the circumferential groove 15 and the inclined groove 16. In other words, the bent portion 17 is a portion where the curvature of the pumping groove 12 changes, and is a bent portion on the downstream side in the relative rotation direction of the pumping groove 12.

[0059] Moreover, four dynamic pressure grooves 13 are formed in the inner diameter side region 11b, which is partitioned by the pumping groove 12, i.e., the side of the fluid F to be sealed. The depth of the dynamic pressure groove 13 is substantially constant. In addition, among the four dynamic pressure grooves 13, the dynamic pressure groove 13 closer to the upstream side in the rotation direction of the rotary seal ring 20 than the inclined groove 16 side of the pumping groove 12 has a longer dimension from the inner diameter end 13a to the outer diameter end 13b.

[0060] More specifically, each dynamic pressure groove 13 extends linearly from the inner diameter end 13a to the outer diameter end 13b toward the downstream side in the rotation direction of the rotary seal ring 20. The inner diameter end 13a of the dynamic pressure groove 13 communicates with the inner space S1, and the outer diameter end 13b as a dynamic pressure generating portion is closed. In addition, the dynamic pressure groove 13 is not limited to a linear shape, and may be an arc shape or the like when viewed in the axial direction.

[0061] Next, Figure 3 The operation when the stationary seal ring 10 and the rotary seal ring 20 rotate relative to each other will be described.

[0062] When the rotary seal ring 20 rotates, as shown by the solid thin arrows in Figure 3 , the fluid F to be sealed in each dynamic pressure groove 13 tends to move following the rotation direction of the rotary seal ring 20 due to the shear with the sliding surface 21. At this time, the fluid F to be sealed is guided along the dynamic pressure groove 13, flows out from the outer diameter end 13b and its vicinity to between the sliding surfaces 11 and 21, and a positive pressure is generated.

[0063] Moreover, when the rotary seal ring 20 rotates, as shown by the hollow arrows in Figure 3 , the fluid F to be sealed in the circumferential groove 15 of the pumping groove 12 follows the rotation direction of the rotary seal ring 20 due to the shear with the sliding surface 21, is guided along the circumferential groove 15 toward the inclined groove 16 side, and is guided along the inclined groove 16 and discharged from the inner diameter end 16a to the inner space S1.

[0064] Moreover, when flowing from the circumferential groove 15 into the inclined groove 16, the flow direction of the fluid F to be sealed changes sharply toward the inner diameter side due to the bent portion 17. At this time, a part of the fluid F to be sealed cannot fully follow the change in the flow direction, flows out from the bent portion 17 and its vicinity to between the sliding surfaces 11 and 21, and a positive pressure is generated.

[0065] On the other hand, a negative pressure is relatively generated within the pumping groove 12. The closer to the end portion 12c of the circumferential groove 15, the greater this negative pressure becomes. That is, the force for sucking in the sealed fluid F becomes stronger.

[0066] Moreover, the circumferential groove 15 is disposed on the outer space S2 side, i.e., the leakage side, of the outer diameter end 13b where a positive pressure is generated in each hydrodynamic groove 13 and its vicinity. And the circumferential groove 15 extends in the circumferential direction in such a manner as to prevent the sealed fluid F flowing out from each hydrodynamic groove 13 to between the sliding surfaces 11 and 12 from moving toward the outer space S2 side. In other words, the circumferential groove 15 and the portion where a positive pressure is generated in each hydrodynamic groove 13 are formed at positions that overlap when observed in the radial direction. Thus, in the present invention, the situation where they are disposed at overlapping positions when observed in the radial direction is expressed as overlapping in the radial direction. Similarly, in the present invention, the situation where they are disposed at overlapping positions when observed in the circumferential direction is expressed as overlapping in the circumferential direction.

[0067] Thereby, most of the sealed fluid F flowing out from each hydrodynamic groove 13 to between the sliding surfaces 11 and 21 is recovered by the circumferential groove 15.

[0068] Moreover, the sealed fluid F not recovered by the circumferential groove 15 also moves following the rotation direction of the rotary seal ring 20 due to shear with the sliding surface 21, and is discharged into the inner space S1 together with the sealed fluid F guided along the inclined groove 16.

[0069] And the end portion 12c of the circumferential groove 15 is disposed at a position on the outer space S2 side that is more outward than the bent portion 17 of the pumping groove 12 adjacent to the upstream side in the rotation direction of the rotary seal ring 20, and overlaps with the bent portion 17 in the radial direction. Therefore, the sealed fluid F flowing out from the bent portion 17 of the circumferential groove 15 on the upstream side and its vicinity to between the sliding surfaces 11 and 21 is also recovered by the pumping groove 12 on the downstream side in the rotation direction.

[0070] As described above, the stationary seal ring 10 of the present embodiment can generate a hydrodynamic pressure in each hydrodynamic groove 13, and can also generate a positive pressure in the pumping groove 12. Thereby, the stationary seal ring 10 can generate a greater hydrodynamic pressure. And the stationary seal ring 10 can use the circumferential groove 15 of the pumping groove 12 to recover the sealed fluid F that flows out from the hydrodynamic groove 13 and wants to flow out to the outer space S2 side. Moreover, the stationary seal ring 10 uses the inclined groove 16 on the downstream side to recover the excess sealed fluid F between the sliding surfaces 11 and 21 that would cause leakage, and returns the sealed fluid F to the inner space S1 side. Thereby, leakage can be suppressed, and a hydrodynamic pressure can also be generated in the pumping groove 12.

[0071] And the stationary seal ring 10 generates a positive pressure at multiple locations, improving the floating balance with the rotary seal ring 20, and thereby lubricity can be improved.

[0072] Moreover, the bent portion 17 of the pumping groove 12 is located circumferentially between two adjacent sets of dynamic pressure grooves 13 and at a position closer to the outer diameter side than each dynamic pressure groove 13. Thus, the stationary seal ring 10 can generate a positive pressure evenly between the sliding surfaces 11 and 12.

[0073] In addition, since the pumping groove 12 and the dynamic pressure groove 13 overlap in the radial direction, the sealed fluid F flowing from the dynamic pressure groove 13 toward the outer space S2 side is easily recovered by the pumping groove 12.

[0074] Moreover, one pumping groove 12 overlaps with four dynamic pressure grooves 13 in the radial direction. Thus, the stationary seal ring 10 can reliably generate a positive pressure at multiple locations. Also, leakage of the sealed fluid F toward the outer space S2 side can be more reliably prevented.

[0075] Furthermore, the radial positions of the outer diameter ends 13b of the four dynamic pressure grooves 13 forming one set are different. More specifically, from the upstream side to the downstream side in the relative rotation direction, the outer diameter ends 13b of the four dynamic pressure grooves 13 are gradually arranged from the outer diameter side toward the inner diameter side. Thereby, a dynamic pressure can be generated at different positions in the radial direction. Thus, the stationary seal ring 10 can further improve the floating balance with the rotating seal ring 20.

[0076] In addition, the number of dynamic pressure grooves in one set can also be one, or a plurality other than four, and can be changed appropriately.

[0077] Moreover, since the inclined groove 16 of the pumping groove 12 inclines from the inner space S1 to the outer space S2 in a direction opposite to each dynamic pressure groove 13, the sealed fluid F can be guided toward the inner space S1 side during relative rotation. Thus, the pumping groove 12 can contribute to preventing leakage.

[0078] Moreover, one set of dynamic pressure grooves 13 is surrounded by the pumping groove 12 that overlaps in the radial and circumferential directions and the inclined groove 16 of the pumping groove 12 adjacent to the pumping groove 12 on the upstream side in the rotation direction of the rotating seal ring 20.

[0079] Thereby, in addition to improving the floating balance with the rotating seal ring 20, the stationary seal ring 10 can recover the sealed fluid F flowing out between the sliding surfaces 11 and 21 from each dynamic pressure groove 13 or the bent portion 17 of each pumping groove 12, and reliably prevent radial leakage.

[0080] Moreover, the sealed fluid F recovered by the pumping groove 12 can be discharged from multiple locations in the circumferential direction into the inner space S1. Thus, not only can the deterioration of the sealed fluid F staying between the sliding surfaces 11 and 21 be suppressed, but also the accumulation of contaminants and the like can be prevented.

[0081] In addition, the circumferential groove 15 widens from the upstream side in the rotation direction of the rotating seal ring 20 toward the downstream side in the rotation direction. Thus, it is easier for the pumping groove 12 to generate a negative pressure relatively within the circumferential groove 15.

[0082] Moreover, the end portion on the upstream side in the rotation direction of the rotary seal ring 20 of the circumferential groove 15 is closed, and the circumferential groove 15 is disposed on the outer space S2 side, i.e., the leakage side. As described above, the more upstream in the rotation direction of the rotary seal ring 20, the greater the negative pressure relatively generated in the circumferential groove 15. Therefore, the circumferential groove 15 can recover the sealed fluid F that has moved to a position on the outer space S2 side beyond the pumping groove 12 located on the upstream side in the rotation direction of the rotary seal ring 20.

[0083] In addition, in the present embodiment, the structure in which the inclined groove 16 of the pumping groove 12 communicates with the inner space S1 has been described, but it is not limited thereto, and reference may also be made to the Figure 4 showing a modified example, such as the inclined groove 116 of the pumping groove 112 of the stationary seal ring 110A, the inner diameter end 116a on the downstream side in the rotation direction of the rotary seal ring 20 is closed.

[0084] If the structure is like this, the sealed fluid F can flow out from the inner diameter end 116a on the downstream side in the rotation direction of the rotary seal ring 20 to between the sliding surfaces 111A and 21, and a positive pressure is generated at and near the inner diameter end 116a. In this way, the inner diameter end 116a of the inclined groove 116 functions as another pressure generating portion of the pumping groove 112.

[0085] And, in Figure 4 , the inner diameter end 116a is located between the circumferences of a set of adjacent dynamic pressure grooves 13 and at a position closer to the inner diameter side than the outer diameter end 13b of each dynamic pressure groove 13. Thereby, a positive pressure can be generated evenly between the sliding surfaces 111A and 21.

[0086] And, in Figure 4 , the pumping groove 112 can discharge a part of the sealed fluid F that has flowed out from the inner diameter end 116a on the downstream side in the rotation direction of the rotary seal ring 20 to between the sliding surfaces 111A and 21 into the inner space S1.

[0087] In addition, in the present embodiment, the structure in which the dynamic pressure groove 13 communicates with the inner space S1 has been described, but it is not limited thereto, and reference may also be made to the Figure 5 showing another modified example, such as the dynamic pressure groove 113 of the stationary seal ring 110B, the end 113a on the upstream side in the rotation direction is closed.

[0088] Even with such a structure, the sealed fluid F flowing into the dynamic pressure groove 113 can move from the end 113a on the upstream side in the rotation direction to the downstream side and flow out between the sliding surfaces 111B and 21 to generate dynamic pressure. And, the negative pressure generated at the end 113a on the upstream side in the rotation direction of the dynamic pressure groove 113 can be utilized to introduce the sealed fluid F from the inner space S1.

[0089] Further, in this embodiment, the hydrodynamic pressure generating groove is exemplified by the hydrodynamic groove 13, but it is not limited thereto. As long as it can generate a positive pressure, for example, it can also be grooves or pits of various shapes such as bent grooves, Rayleigh steps, spiral grooves, herringbone shapes, etc., and its structure can be appropriately changed.

[0090] Embodiment 2

[0091] Next, refer to Figure 6 、 Figure 7 to describe the sliding member of Embodiment 2. In addition, the repeated structural descriptions of the same structures as those in the foregoing Embodiment 1 are omitted.

[0092] On the sliding surface 211 of the stationary seal ring 210 in this Embodiment 2, a plurality of pumping grooves 212 and a plurality of hydrodynamic grooves 13 are formed.

[0093] The pumping groove 212 has a circumferential groove 215 and a bent inclined groove 216.

[0094] The bent inclined groove 216 extends from the end of the circumferential groove 215 on the downstream side in the rotation direction of the rotary seal ring 20 toward the inner space S1 in a gently curved arc shape protruding toward the outer diameter side. Thus, the bent portion 217 of the bent inclined groove 216 is formed gentler than the bent portion 17 of Embodiment 1. That is, the bent portion 217 is in a bent shape. In other words, the bent portion 217 is the portion where the curvature of the bent inclined groove 216 changes, and is the bent portion on the downstream side of the relative rotation direction of the pumping groove 212.

[0095] Thus, compared with the pumping groove 12 of Embodiment 1, the positive pressure generated at the bent portion 217 of the pumping groove 212 in this embodiment is suppressed, and it is easy to discharge the recovered fluid into the inner space S1.

[0096] In addition, reference can also be made to Figure 7 showing a modified example. As in the bent inclined groove 216A of the pumping groove 212A in the stationary seal ring 210A, it extends from the end of the circumferential groove 15 on the downstream side in the rotation direction of the rotary seal ring 20 toward the inner space S1 in an arc shape protruding toward the inner diameter side. Thus, the bent portion 217A of the pumping groove 212A is formed sharper than the bent portion 17 of Embodiment 1.

[0097] Thus, compared with the pumping groove 12 of Embodiment 1, the positive pressure generated at the bent portion 217A of the pumping groove 212A becomes higher, and the flow rate returning to the inner space S1 becomes smaller.

[0098] Embodiment 3

[0099] Next, refer to Figure 8 to describe the sliding member of Embodiment 3. In addition, the repeated structural descriptions of the same structures as those in the foregoing Embodiment 1 are omitted.

[0100] On the sliding surface 311 of the stationary seal ring 310 in the third embodiment, a plurality of pumping grooves 312 and a plurality of hydrodynamic grooves 13 are formed.

[0101] The pumping groove 312 has a circumferential groove 315, an inclined groove 16, and an upstream inclined groove 316.

[0102] The upstream inclined groove 316 is inclined from the end on the upstream side in the rotation direction of the rotary seal ring 20 of the circumferential groove 315 toward the downstream side in the rotation direction of the rotary seal ring 20 and extends substantially linearly toward the inner diameter side. Moreover, the inner diameter end 312h of the upstream inclined groove 316 is closed.

[0103] Thereby, the pumping groove 312 can generate a positive pressure at the inner diameter end 312h of the upstream inclined groove 316 and in its vicinity. In this way, the inner diameter end 312h functions as another pressure generating portion of the pumping groove 12.

[0104] Moreover, the inner diameter end 312h of the upstream inclined groove 316 is arranged at a position closer to the inner diameter side than the bent portion 17. Therefore, one pumping groove 312 can generate a positive pressure at a plurality of positions different in the radial direction.

[0105] In addition, the pressure generating portions of the fluid recovery groove in which the pressure generating portions are formed at multiple locations may be at substantially the same position in the radial direction.

[0106] Embodiment 4

[0107] Next, the sliding member of the fourth embodiment will be described. In addition, the description of the structure that is the same as that of the foregoing first embodiment will be omitted. Figure 9

[0108] On the sliding surface 411 of the stationary seal ring 410 in the fourth embodiment, a plurality of pumping grooves 412 and a plurality of hydrodynamic grooves 13 are formed.

[0109] The pumping groove 412 has a circumferential groove 415, an inclined groove 16, and six outer diameter side inclined grooves 418.

[0110] The outer diameter side inclined groove 418 communicates with the circumferential groove 415, is inclined from the circumferential groove 415 toward the upstream side in the rotation direction of the rotary seal ring 20, and extends substantially linearly toward the outer diameter side. Moreover, the outer diameter end 418a of the outer diameter side inclined groove 418 is closed. Moreover, the depth of the outer diameter side inclined groove 418 is substantially constant and is substantially the same as the depths of the circumferential groove 415 and the inclined groove 16, respectively.

[0111] Moreover, among the six outer diameter side inclined grooves 418, the outer diameter side inclined groove 418 closer to the upstream side in the rotation direction of the rotary seal ring 20 than the inclined groove 416 side of the pumping groove 412 has a longer dimension from the circumferential groove 415 to the outer diameter end 418a of the outer diameter side inclined groove 418.​

[0112] Thus, the pumping groove 412 can also recover the sealed fluid F that has moved to a position on the outer diameter side of the circumferential groove 415 by using each outer diameter side inclined groove 418.

[0113] Moreover, the radial positions of the outer diameter ends 418a of the six outer diameter side inclined grooves 418 are different. Therefore, the six outer diameter side inclined grooves 418 can recover the sealed fluid F in a wider range.

[0114] Embodiment 5

[0115] Next, a sliding member of Embodiment 5 will be described with reference to Figure 10 In addition, the description of the structure that is the same as that of the aforementioned Embodiment 1 will be omitted.

[0116] On the sliding surface 511 of the stationary seal ring 510 of the present Embodiment 5, a plurality of pumping grooves 12, a plurality of hydrodynamic grooves 13, and a plurality of outer diameter side hydrodynamic grooves 519 are formed.

[0117] Compared with Embodiment 1, the adjacent pumping grooves 12 are separated and arranged at a predetermined interval. Three outer diameter side hydrodynamic grooves 519 are arranged in a group between these adjacent pumping grooves 12.

[0118] The outer diameter side hydrodynamic groove 519 communicates with the outer space S2, is inclined from the outer space S2 toward the downstream side in the rotation direction of the rotary seal ring 20, and extends substantially linearly toward the inner diameter side. Moreover, the inner diameter end 519a of the outer diameter side hydrodynamic groove 519 is closed. And the depth of the outer diameter side hydrodynamic groove 519 is substantially constant and is substantially the same as the depth of each hydrodynamic groove 13.

[0119] Moreover, among the three outer diameter side hydrodynamic grooves 519, the outer diameter side hydrodynamic groove 519 closer to the upstream side in the rotation direction has a longer dimension from the outer diameter end to the inner diameter end 519a than the downstream side in the rotation direction of the rotary seal ring 20.

[0120] Thus, the three outer diameter side hydrodynamic grooves 519 can recover the sealed fluid F that wants to move to the outer space S2, and a positive pressure is generated at and near the inner diameter end 519a.

[0121] Moreover, the radial positions of the inner diameter ends 519a of the three outer diameter side hydrodynamic grooves 519 are different. Therefore, the three outer diameter side hydrodynamic grooves 519 can generate a positive pressure at a plurality of different positions in the radial direction.

[0122] In this way, in the sliding member of the present invention, in addition to the hydrodynamic generation groove and the fluid recovery groove, grooves, pits, etc. that can generate hydrodynamic pressure can also be provided.

[0123] Embodiment 6

[0124] Next, a description will be given with reference to Figure 11 the sliding member of Example 6. In addition, redundant structural descriptions of the same structures as those in the aforementioned Example 1 will be omitted.

[0125] On the sliding surface 611 of the stationary seal ring 610 in this Example 6, a plurality of pumping grooves 612 and a plurality of hydrodynamic grooves 13 are formed.

[0126] The pumping groove 612 has a circumferential groove 15, an inclined groove 616, and an inner diameter side circumferential groove 615.

[0127] The inner diameter side circumferential groove 615 extends in the circumferential direction, and its circumferential center communicates with the inner diameter end of the inclined groove 616. Moreover, the end 612m on the downstream side in the rotation direction of the rotary seal ring 20 of the inner diameter side circumferential groove 615, the end 612n on the upstream side in the rotation direction, and the inner diameter end 612p of the inner diameter side circumferential groove 615 are closed. In other words, the end 612m is the circumferential end on the downstream side in the relative rotation direction of the pumping groove 612.

[0128] Thereby, the pumping groove 612 can generate a positive pressure at the end 612m on the downstream side in the rotation direction of the rotary seal ring 20 of the inner diameter side circumferential groove 615 and in its vicinity. Thus, the end 612m functions as another pressure generating portion of the pumping groove 12.

[0129] Moreover, a negative pressure is relatively generated in the inner diameter side circumferential groove 615. The closer to the end 612n on the upstream side in the rotation direction of the rotary seal ring 20 of the inner diameter side circumferential groove 615, the greater this negative pressure. Thereby, the inner diameter side circumferential groove 615 can efficiently recover the sealed fluid F, particularly the sealed fluid F that flows out between the sliding surfaces 611 and 21 from the hydrodynamic groove 13 that overlaps the pumping groove 612 in the circumferential and radial directions.

[0130] Moreover, the end 612m on the downstream side in the rotation direction of the rotary seal ring 20 of the inner diameter side circumferential groove 615 overlaps with the circumferential groove 15 of the adjacent pumping groove 612 in the radial direction. Therefore, the sealed fluid F that flows out between the sliding surfaces 611 and 21 from the end 612m and in its vicinity is recovered by the pumping groove 612 located on the downstream side in the rotation direction.

[0131] Moreover, when the rotation direction of the rotary seal ring 20 is reversed, that is, when the rotary seal ring 20, which is the opposing seal ring, slides relatively clockwise, the inner diameter side circumferential groove 615 can generate a positive pressure at the end 612n on the upstream side in the rotation direction of the rotary seal ring 20 and in its vicinity. This is the same for the circumferential groove 15.

[0132] In addition, a structure in which the inclined groove 616 of the pumping groove 612 communicates with the circumferential center of the inner diameter side circumferential groove 615 has been described, but it is not limited thereto, and the inclined groove may communicate with a portion other than the circumferential center of the inner diameter side circumferential groove.

[0133] Moreover, a structure in which the pumping groove 612 extends from the portion where the inner diameter side circumferential groove 615 communicates with the inclined groove 616 to the circumferential upstream side has been described, but it is not limited thereto. As a modification example, it may be a Z-shaped, in other words, a crank shape, like the pumping groove 612A shown Figure 12 in the figure.

[0134] Specifically, the upstream end of the inner diameter side circumferential groove 615A of the pumping groove 612A communicates with the inner diameter end of the inclined groove 616. In other words, the pumping groove 612A omits the portion of the inner diameter side circumferential groove 615 in the upstream side in the rotation direction from the inclined groove 616. By adopting such a pumping groove 612A, a larger number of hydrodynamic grooves 13 can be provided.

[0135] Embodiment 7

[0136] Next, the sliding member of Embodiment 7 will be described with reference to Figure 13 the figure. In addition, the description of the structure that is the same as that in the aforementioned Embodiment 1 will be omitted.

[0137] On the sliding surface 711 of the stationary seal ring 710 in the present Embodiment 7, a plurality of pumping grooves 712, a plurality of hydrodynamic grooves 13, and a plurality of counter-hydrodynamic grooves 13' are formed.

[0138] The pumping groove 712 has a circumferential groove 715, an inclined groove 16, a counter-circumferential groove 715', and a counter-inclined groove 16'.

[0139] The two counter-hydrodynamic grooves 13', counter-circumferential groove 715', and counter-inclined groove 16' that overlap with one pumping groove 712 in the radial and circumferential directions are obtained by flipping the two hydrodynamic grooves 13, circumferential groove 715, and inclined groove 16 that overlap with the one pumping groove 712 in the radial and circumferential directions along the circumferential direction with the upstream end in the rotation direction of the circumferential groove 715 of the rotary seal ring 20 as the boundary. And the upstream end in the rotation direction of the circumferential groove 715 of the rotary seal ring 20 communicates with the downstream end in the rotation direction of the counter-circumferential groove 715'.

[0140] Thus, as shown by the solid line arrow, when the rotary seal ring 20 slides counterclockwise relatively, a positive pressure is generated at the bent portion 17 of the circumferential groove 715 and its vicinity and the inclined groove 16. And the sealed fluid F is discharged from the inclined groove 16 to the inner space S1.

[0141] On the other hand, as shown by the dashed arrow, when the rotary seal ring 20 slides relatively clockwise, a positive pressure is generated at the bent portion 17' of the counterclockwise groove 715' and the counterinclined groove 16' and in the vicinity thereof. Also, the fluid F to be sealed is discharged from the counterinclined groove 16' into the inner space S1.

[0142] In this way, the hydrodynamic pressure generating groove and the fluid recovery groove are configured in a circumferentially symmetric shape, whereby positive pressure generation and fluid recovery can be achieved regardless of whether the rotation direction is one direction or the other. Also, as long as positive pressure generation and fluid recovery can be achieved on the one side and the other side of the rotation direction respectively, the shapes of the hydrodynamic pressure grooves and the fluid recovery grooves for achieving positive pressure generation and fluid recovery on the one side of the rotation direction may be different from the shapes of the hydrodynamic pressure grooves and the fluid recovery grooves for achieving positive pressure generation or fluid recovery on the other side of the rotation direction. That is, it may not be a symmetric shape.

[0143] Example 8

[0144] Next, a sliding member of Example 8 will be described with reference to Figure 14 In addition, the description of the structure that is the same as that of the aforementioned Example 1 will be omitted.

[0145] On the sliding surface 1011 of the stationary seal ring 1010 of the present Example 8, a plurality of pumping grooves 1012 and a plurality of hydrodynamic pressure grooves 13 are formed.

[0146] The end portion 1015c on the upstream side in the rotation direction of the rotary seal ring 20 of each circumferential groove 1015 overlaps with the bent portion 1017 of the pumping groove 1012 adjacent to the upstream side in the rotation direction of the rotary seal ring 20 in the circumferential direction.

[0147] Also, each circumferential groove 1015 extends linearly. Therefore, by extending each circumferential groove 1015 in the circumferential direction, a dodecagon can be drawn. Also, the number of circumferential grooves 1015 may be a number other than 12, and in this case, a polygon having that number of sides can be drawn.

[0148] Thereby, the pumping groove 1012 can efficiently recover the fluid F to be sealed that has flowed out from the bent portion 1017 of the pumping groove 1012 adjacent to the upstream side in the rotation direction of the rotary seal ring 20 between the sliding surfaces 1011 and 21.

[0149] Example 9

[0150] Next, a sliding member of Example 9 will be described with reference to Figure 15 In addition, the description of the structure that is the same as that of the aforementioned Example 1 will be omitted.

[0151] On the sliding surface 1111 of the stationary seal ring 1110 of the present Example 9, a plurality of pumping grooves 1112 and a plurality of hydrodynamic pressure grooves 13 are formed.

[0152] The circumferential grooves 1115 of each pumping groove 1112 are formed as arcs of the same curvature and are arranged on the same circumference. Moreover, the curvature of each circumferential groove 1115 is substantially the same as the curvature of the stationary seal ring 1110. Furthermore, by extending each circumferential groove 1115 in the circumferential direction, a circle can be drawn.

[0153] Moreover, the upstream end 1115c on the upstream side in the rotational direction of the circumferential groove 1115 of the rotating seal ring 20 overlaps with the bent portion 1117 of the pumping groove 1112 adjacent to the upstream side in the rotational direction of the rotating seal ring 20 in the circumferential direction.

[0154] Thus, the circumferential groove 1115 can guide the sealed fluid F along the rotational direction. Also, the sealed fluid F flowing out from the bent portion 1117 of the pumping groove 1112 adjacent to the upstream side in the rotational direction of the rotating seal ring 20 between the sliding surfaces 1111 and 21 also easily moves along the rotational direction. Thus, the stationary seal ring 1110 can recover the sealed fluid F without omission.

[0155] Example 10

[0156] Next, with reference to Figure 16 the sliding member of Example 10 will be described. In addition, the description of the repeated structures that are the same as those in the aforementioned Example 1 will be omitted.

[0157] On the sliding surface 1211 of the stationary seal ring 1210 in this Example 10, a plurality of pumping grooves 1212 and a plurality of hydrodynamic grooves 13 serving as fluid recovery grooves are formed.

[0158] In the pumping groove 1212, the circumferential groove 1215 and the inclined groove 1216 are radially partitioned by the land portion 1214. That is, the circumferential groove 1215 and the inclined groove 1216 are not connected. In other words, the end portion 1215m is the circumferential end portion on the relatively downstream side in the rotational direction of the pumping groove 1212. In addition, from the viewpoint of recovering the fluid, the separation distance between the circumferential groove 1215 and the inclined groove 1216 is preferably equal to or less than the separation distance between the circumferential groove 1215 and the hydrodynamic groove 13.

[0159] Thus, a positive pressure is generated at the end portion 1215b serving as a pressure generation portion and its vicinity on the relatively rotationally downstream side of the circumferential groove 1215 of the rotating seal ring 20, and a part of the fluid flowing out from the end portion 1215b between the sliding surfaces can be recovered by the inclined groove 1216. And another part of the fluid flowing out from the end portion 1215b between the sliding surfaces is recovered by the circumferential groove 1215 of the pumping groove 1212 on the relatively rotationally downstream side.

[0160] Example 11

[0161] Next, with reference toFigure 17 The sliding member of Embodiment 11 will be described. In addition, the description of the repeated structures identical to those of the foregoing Embodiment 1 will be omitted.

[0162] On the sliding surface 1311 of the stationary seal ring 1310 of the present Embodiment 11, a plurality of pumping grooves 1312 and a plurality of hydrodynamic grooves 13 are formed.

[0163] The pumping groove 1312 communicates with the inclined groove 1316 at a position away from the end portion 1315b, which is a pressure generating portion, on the relatively rotation downstream side of the circumferential groove 1315 of the rotating seal ring 20 toward the relatively rotation upstream side. The end portion 1315b is the circumferential end portion on the relatively rotation downstream side of the pumping groove 1312.

[0164] Thereby, a positive pressure can be generated at the end portion 1315b of the circumferential groove 1315 and its vicinity. And, another part of the fluid flowing out between the sliding surfaces to the relatively rotation downstream side is recovered by the circumferential groove 1315 of the pumping groove 1312.

[0165] Embodiment 12

[0166] Next, with reference to Figure 18 The sliding member of Embodiment 12 will be described. In addition, the description of the repeated structures identical to those of the foregoing Embodiment 1 will be omitted.

[0167] The mechanical seal using the stationary seal ring 810 of the present Embodiment 12 is an inner type mechanical seal that seals the fluid F to be sealed existing on the outer space S12 side of the sliding surfaces 811, 21 and the inner space S11 communicates with the atmosphere A.

[0168] On the sliding surface 811, a plurality of pumping grooves 812 and a plurality of hydrodynamic grooves 813 are formed.

[0169] The pumping groove 812 has a circumferential groove 815 and an inclined groove 816.

[0170] The inclined groove 816 has a shape obtained by substantially turning over the inclined groove 16 of the foregoing Embodiment 1 along the radial direction and communicates with the circumferential groove 815. The hydrodynamic groove 813 is obtained by substantially turning over the hydrodynamic groove 13 of the foregoing Embodiment 1 along the radial direction and communicates with the outer space S12.

[0171] Thereby, as Figure 18 indicated by the hollow arrow, by rotating the rotating seal ring 20, a positive pressure is generated at the inner diameter end of the hydrodynamic groove 813 and its vicinity. And, a positive pressure is generated at the bent portion 817 of the circumferential groove 815 and the inclined groove 816 and its vicinity. Moreover, the fluid F to be sealed is discharged from the inclined groove 816 to the outer space S12.

[0172] Thus, the sliding member of the present invention can also be applied to an environment where the fluid space to be sealed is on the outer diameter side of the sliding surface and the leakage side space is on the inner diameter side of the sliding surface.

[0173] Example 13

[0174] Next, with reference to Figure 19 the sliding member of Example 13 will be described. In addition, the description of the structure that is the same as that of the aforementioned Example 1 will be omitted.

[0175] On the sliding surface 911 of the stationary seal ring 910 in this Example 13, a plurality of pumping grooves 912 and a plurality of hydrodynamic grooves 13 are formed.

[0176] The pumping groove 912 has an inclined groove 916 as the first groove portion and a reverse inclined groove 916' as the second groove portion.

[0177] The reverse inclined groove 916' is a shape obtained by radially flipping the downstream end in the rotation direction of the rotating seal ring 20 of the inclined groove 916. And the downstream end in the rotation direction of the reverse inclined groove 916', that is, the outer diameter end of the reverse inclined groove 916', communicates with the downstream end in the rotation direction of the inclined groove 916, that is, the inner diameter end of the inclined groove 916. The pumping groove 912 is a substantially L-shaped groove with an obtuse crossing angle.

[0178] And, the inclined groove 916 is arranged at a position on the outer diameter side of one hydrodynamic groove 13 and overlaps with one hydrodynamic groove 13 in the radial direction and the circumferential direction.

[0179] Thus, when the rotating seal ring 20 rotates, as Figure 19 shown by the hollow arrow, the sealed fluid F in the inclined groove 916 moves following the rotation direction of the rotating seal ring 20 due to the shear with the sliding surface 21 and is guided along the inclined groove 916 to the bent portion 917 of the inclined groove 916 and the reverse inclined groove 916'.

[0180] Similarly, the sealed fluid F in the reverse inclined groove 916' is also guided along the reverse inclined groove 916' to the bent portion 917.

[0181] Then, the sealed fluid F flows out from the bent portion 917 and its vicinity to between the sliding surfaces 911 and 21, generating a positive pressure. Thus, the bent portion 917 functions as a pressure generating portion of the pumping groove 912. In other words, the bent portion 917 is the folded end portion on the downstream side in the relative rotation direction of the pumping groove 912.

[0182] Moreover, relative negative pressures are respectively generated within the inclined groove 916 and the reverse inclined groove 916'. The closer to the upstream side in the rotational direction of the rotary seal ring 20, the greater these negative pressures become. Therefore, the pumping groove 912 can efficiently recover the sealed fluid F, particularly the sealed fluid F that flows out between the sliding surfaces 911 and 21 from the dynamic pressure groove 13 that overlaps the pumping groove 912 both circumferentially and radially.

[0183] In addition, the substantially L-shaped groove formed by the inclined groove and the reverse inclined groove as in the present embodiment can be continuous with the circumferential groove 15 of the aforementioned Embodiment 1 and extend circumferentially, or can be continuous with the inclined groove 16 of the aforementioned Embodiment 1 and communicate with the inner space S1.

[0184] Moreover, in the present embodiment, the shape of the bending groove having a bending angle is illustrated, but it is not limited thereto, and it may also be a shape having a curved portion with a large curvature.

[0185] Furthermore, in the present embodiment, the case where one pressure generating portion is constituted by one inclined groove and one reverse inclined groove is described, but it is not limited thereto. For example, a plurality of inclined grooves and a plurality of reverse inclined grooves may be alternately arranged to form multiple pressure generating portions.

[0186] The embodiments of the present invention have been described above with reference to the drawings, but the specific structure is not limited to these embodiments, and changes and additions within the scope not departing from the gist of the present invention are also included in the present invention.

[0187] For example, in the aforementioned Embodiments 1 to 13, a mechanical seal is described as an example of the sliding member, but it is not limited thereto, and it may also be a sliding member other than a mechanical seal such as a sliding bearing.

[0188] Moreover, in the aforementioned Embodiments 1 to 13, the case where the sealed fluid is a high-pressure liquid is described, but it is not limited thereto, and it may also be a gas or a low-pressure liquid, or may be a mist mixture of liquid and gas.

[0189] Furthermore, in the aforementioned Embodiments 1 to 13, the case where the fluid on the leakage space side is the atmosphere as a low-pressure gas is described, but it is not limited thereto, and it may also be a liquid or a high-pressure gas, or may be a mist mixture of liquid and gas.

[0190] Moreover, in the aforementioned Embodiments 1 to 13, the sealed fluid space side is described as the high-pressure side and the leakage space side is described as the low-pressure side, but it may also be that the sealed fluid space side is the low-pressure side and the leakage space side is the high-pressure side, or it may be that the sealed fluid space side and the leakage space side have substantially the same pressure.

[0191] Further, in the aforementioned Embodiments 1 to 13, an example in which the hydrodynamic pressure generating groove and the fluid recovery groove are provided in the stationary seal ring has been described. However, the hydrodynamic pressure generating groove and the fluid recovery groove may also be provided in the rotating seal ring.

[0192] Further, in the aforementioned Embodiments 1 to 12, a structure in which the circumferential groove widens from the upstream side in the rotation direction of the rotating seal ring toward the downstream side in the rotation direction has been described. However, it is not limited thereto, and the width may be constant, may narrow, and its shape may be appropriately changed.

[0193] Reference Numeral Explanation

[0194] 10: stationary seal ring (sliding member); 11: sliding surface; 12: pumping groove (fluid recovery groove); 13: hydrodynamic pressure groove (hydrodynamic pressure generating groove); 15: circumferential groove (first groove); 16: inclined groove (second groove); 17: bent portion (pressure generating portion); 20: rotating seal ring (sliding member); 21: sliding surface; 110A, 110B: stationary seal rings; 111A, 111B: sliding surfaces; 112: pumping groove (fluid recovery groove); 113: hydrodynamic pressure groove (hydrodynamic pressure generating groove); 210 to 1310: stationary seal rings; 211 to 1311: sliding surfaces; 212 to 412, 612 to 1112, 1312: pumping grooves (fluid recovery grooves); 315, 415, 715, 815, 1015 to 1315: circumferential grooves (first groove portions); 116, 416, 616, 816 to 1316: inclined grooves (second groove portions); 216, 216A: bent inclined grooves (second groove portions); 217, 217A, 817 to 1117: bent portions (pressure generating portions); 1212: pumping groove (fluid recovery groove); 1215b, 1315b: end portions (pressure generating portions); 13': reverse hydrodynamic pressure groove; 16': reverse inclined groove (second groove portion); 17': bent portion (pressure generating portion); 813: hydrodynamic pressure groove (hydrodynamic pressure generating groove); 916': reverse inclined groove (second groove portion); A: atmosphere (fluid on the leakage space side); F: fluid to be sealed; S1, S11: inner spaces; S2, S12: outer spaces.

Claims

1. A sliding member, wherein a pair of sliding surfaces of the sliding member rotate relative to each other, and the sliding member divides between a fluid space to be sealed and a leakage space, where a hydrodynamic generating groove and a fluid recovery groove are provided on at least any one of the sliding surfaces, and the fluid recovery groove has a pressure generating portion which is a circumferential end portion, a bent portion or a folded portion on the downstream side in the relative rotation direction, the fluid recovery groove has: a first groove portion which overlaps with the hydrodynamic generating groove in the radial direction at a position closer to the leakage space than the hydrodynamic generating groove; and a second groove portion which overlaps with the hydrodynamic generating groove in the circumferential direction at a position closer to the downstream side of the relative rotation than the hydrodynamic generating groove.

2. The sliding member according to claim 1, wherein the pressure generating portion is a bent portion between the first groove portion and the second groove portion which is bent or folded from the first groove portion and extends radially toward the fluid space to be sealed.

3. The sliding member according to claim 1, wherein the fluid recovery groove overlaps with a plurality of the hydrodynamic generating grooves in the radial direction.

4. The sliding member according to claim 1, wherein the second groove portion inclines from the fluid space to be sealed toward the leakage space in a direction opposite to the hydrodynamic generating groove.

5. The sliding member according to claim 2, wherein the upstream end of the first groove portion of the fluid recovery groove overlaps with the bent portion of the fluid recovery groove adjacent in the upstream side of the relative rotation in the circumferential direction.

6. The sliding member according to claim 2, wherein adjacent first groove portions are arranged on the same circumference.

7. The sliding member according to claim 1, wherein the first groove portion of the fluid recovery groove overlaps with the second groove portion of the fluid recovery groove adjacent in the upstream side of the relative rotation in the radial direction, and the hydrodynamic generating groove is surrounded by the fluid recovery groove and the second groove portion of the fluid recovery groove adjacent in the upstream side of the relative rotation.

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