Sliding member

Abstract

Provided is a sliding member capable of improving lubricity. A sliding member (10, 20) having a pair of sliding surfaces (11, 21) that rotate relative to each other, the sliding member (10, 20) partitioning a space (S1) for fluid to be sealed and a leakage space (S2), the sliding member (10, 20) having, on at least one of the sliding surfaces (11): a dynamic pressure generating groove (13); a fluid recovery tank (14) that is provided further toward the leakage space (S2) side than the dynamic pressure generation tank (13), and that has a pressure generation section (143), which is a circumferential end section, a curved section, or a bent section, on the downstream side in the relative rotation direction; and a surrounding groove (15) provided between the dynamic pressure generating groove (13) and the fluid recovery groove (14) in the radial direction and extending in the circumferential direction.

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 against each other. In such a mechanical seal, in recent years, in order to address environmental measures and the like, it has been desired to reduce the energy loss due to sliding.

[0003] For example, in the mechanical seal shown in Patent Document 1, a plurality of recesses are provided in the circumferential direction on the sliding surface of the stationary seal ring. The recesses 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. Further, 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 recesses 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 loss due to sliding can be reduced. Further, by means of the negative pressure generated at the upstream end in the rotation direction of the cavitation formation region, the recesses 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, 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 recesses 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 recesses are scattered in the circumferential direction and are arranged close to the fluid space to be sealed side. As a result, the positive pressure generated between the sliding surfaces becomes uneven in the circumferential and radial directions, 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 a problem, and an object thereof is to provide a sliding member capable of improving lubricity.

[0011] Means for Solving the Problem

[0012] 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 fluid-sealed space and a leakage space. Among them, on at least any one of the sliding surfaces, there are: a hydrodynamic pressure generating groove; a fluid recovery groove, which is provided at a position closer to the leakage space side than the hydrodynamic pressure generating groove, and has at least one pressure generating portion as a circumferential end portion, a bent portion or a folded portion; and an annular groove, which is provided between the radial directions of the hydrodynamic pressure generating groove and the fluid recovery groove and extends in the circumferential direction.

[0013] Thus, it is possible to generate a positive pressure at different positions in the radial direction of the sliding surface by the pressure generating portions of the hydrodynamic pressure generating groove and the fluid recovery groove. Moreover, since the fluid-sealed space side and the leakage space side of the sliding surface are separated by the annular groove, it is possible to suppress the interference between the positive pressure generated in the hydrodynamic pressure generating groove and the positive pressure generated in the fluid recovery groove. Thus, a positive pressure is stably generated at multiple positions in the circumferential and radial directions, the floating balance between the sliding members is improved, and thus the lubricity can be improved.

[0014] Alternatively, the fluid recovery groove may have a first groove portion extending in the circumferential direction and a second groove portion that bends or folds from the first groove portion and extends toward the annular groove, and the pressure generating portion is the bent portion between the first groove portion and the second groove portion.

[0015] Thus, it is possible to generate a positive pressure at the bent portion between the first groove portion and the second groove portion, and it is possible to guide the fluid in the fluid recovery groove to the annular groove.

[0016] Alternatively, the annular groove may be circular.

[0017] Thus, the fluid-sealed space side and the leakage space side are separated over the entire circumference in the circumferential direction, so it is possible to further prevent the interference between the positive pressure generated in the hydrodynamic pressure generating groove and the positive pressure generated in the fluid recovery groove.

[0018] Alternatively, the fluid recovery groove may communicate with the annular groove.

[0019] Thus, it is possible not to generate a positive pressure at the circumferential side end portion of the second groove portion of the fluid recovery groove on the annular groove side, so it will not affect the positive pressure at the hydrodynamic pressure generating groove. And it is possible to reliably recover the fluid using the fluid recovery groove.

[0020] Alternatively, the sliding member may have a communication groove that communicates the annular groove with the fluid-sealed space.

[0021] Thus, it is possible to prevent the positive pressure on the sealed fluid space side of the sliding surface from becoming too high.

[0022] Alternatively, the surrounding groove may be deeper than the fluid recovery groove.

[0023] Thus, it is easy to recover the sealed fluid flowing out between the sliding surfaces using the surrounding groove. Moreover, it is possible to prevent the positive pressure on the sealed fluid space side of the sliding surface from becoming too high.

[0024] Alternatively, the upstream end of the first groove portion of the fluid recovery groove may overlap with the bent portion of the fluid recovery groove adjacent on the upstream side of the relative rotation in the circumferential direction.

[0025] 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.

[0026] Alternatively, the adjacent first groove portions may be arranged on the same circumference.

[0027] Thus, the first groove portion can guide the sealed fluid along the rotation 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 also easily moves along the rotation direction. Thus, the sliding member can recover the sealed fluid without omission. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a longitudinal sectional view showing an example of a mechanical seal according to Embodiment 1 of the present invention.

[0029] Figure 2 is a view of the sliding surface of the stationary seal ring of Embodiment 1 as observed axially.

[0030] Figure 3 is Figure 2 a partial enlarged view of

[0031] Figure 4 is a view of the sliding surface of the stationary seal ring of Embodiment 2 of the present invention as observed axially.

[0032] Figure 5 is a partial enlarged view of the sliding surface of the stationary seal ring of Embodiment 3 of the present invention as observed axially.

[0033] Figure 6 is a partial enlarged view of the sliding surface of the stationary seal ring of Embodiment 4 of the present invention as observed axially.

[0034] Figure 7 is a partial enlarged view of the sliding surface of the stationary seal ring of Embodiment 5 of the present invention as observed axially.

[0035] Figure 8 It is a partial enlarged view of the sliding surface of the stationary seal ring of Example 6 of the present invention as observed axially.

[0036] Figure 9 It is a partial enlarged view of the sliding surface of the stationary seal ring of Example 7 of the present invention as observed axially.

[0037] Figure 10 It is a partial enlarged view of the sliding surface of the stationary seal ring of Example 8 of the present invention as observed axially.

[0038] Figure 11 It is a partial enlarged view of the sliding surface of the stationary seal ring of Example 9 of the present invention as observed axially.

[0039] Figure 12 It is a partial enlarged view of the sliding surface of the stationary seal ring of Example 10 of the present invention as observed axially.

[0040] Figure 13 It is a partial enlarged view of the sliding surface of the stationary seal ring of Example 11 of the present invention as observed axially.

[0041] Figure 14 It is a partial enlarged view of the sliding surface of the stationary seal ring of Example 12 of the present invention as observed axially.

[0042] Figure 15 It is a view of the sliding surface of the stationary seal ring of Example 13 of the present invention as observed axially.

[0043] Figure 16 It is a view of the sliding surface of the stationary seal ring of Example 14 of the present invention as observed axially.

[0044] Figure 17 It is a partial enlarged view of the sliding surface of the stationary seal ring of Example 15 of the present invention as observed axially.

[0045] Figure 18 It is a view of the sliding surface of the stationary seal ring of Example 16 of the present invention as observed axially.

[0046] Figure 19 It is a view of the sliding surface of the stationary seal ring of Example 17 of the present invention as observed axially. Detailed Description of the Invention

[0047] Hereinafter, a method for implementing the sliding member of the present invention will be described based on examples.

[0048] Example 1

[0049] Refer to Figures 1 to 3 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 taken as an example for description.

[0050] Also, a fluid F to be sealed as the first fluid exists in the inner space S1 of the mechanical seal, and the atmosphere A as the second fluid exists in the outer space S2. The inner diameter side of the sliding member constituting the mechanical seal is taken as the fluid space side to be sealed (high-pressure side), and the outer diameter side is taken as the leakage space side (low-pressure side) for explanation. Also, for ease of explanation, in the drawings, points may sometimes be marked on grooves or the like formed on the sliding surface.

[0051] Figure 1 The shown mechanical seal is an outer type mechanical seal that seals the fluid F to be sealed 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 the present embodiment, a mode is exemplified in which the fluid F to be sealed is a high-pressure liquid and the atmosphere A is a gas at a lower pressure than the fluid F to be sealed.

[0052] 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 so as to be able to rotate together with the rotating shaft 1. The stationary seal ring 10 is provided on the seal housing 5 in a non-rotating state and in a state capable of moving axially, and the seal housing 5 is fixed to the housing 4 of the equipment to be installed. 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 the flat surface.

[0053] 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, and any sliding material that can be used as a sliding material for a mechanical seal can be used. In addition, as SiC, there are materials composed of two or more phases with different compositions, such as sintered bodies using 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. 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 modification materials (coating materials), composite materials, etc. can also be used.

[0054] As Figure 2 and Figure 3 shown, relative to the stationary seal ring 10, the rotating seal ring 20 as the opposing seal ring slides counterclockwise relatively as shown by the solid line arrow.

[0055] On the sliding surface 11 of the stationary seal ring 10, there are provided a dynamic pressure groove 13 as a dynamic pressure generating groove, a fluid recovery groove 14, and an annular groove 15 as a surrounding groove.

[0056] The dynamic pressure grooves 13 are circumferentially and equally disposed on the inner diameter side of the sliding surface 11 (for example, 36 in this embodiment).

[0057] The dynamic pressure groove 13 is inclined from the inner diameter end 13a toward the outer diameter end 13b toward the downstream side in the rotation direction of the rotary seal ring 20, that is, the relative rotation downstream side, and extends in an arc shape. The inner diameter end 13a of the dynamic pressure groove 13 communicates with the inner space S1, and the outer diameter end 13b as the dynamic pressure generating portion is closed.

[0058] In addition, the dynamic pressure groove 13 is not limited to being arc-shaped when viewed axially, and may also be linear, Rayleigh step, spiral groove, chevron shape, etc. Also, it may be a pit surrounded by lands.

[0059] An annular groove 15 is provided on the outer diameter side of the dynamic pressure groove 13. The annular groove 15 is provided concentrically with the stationary seal ring 10. The portion of the sliding surface 11 other than the dynamic pressure groove 13, the fluid recovery groove 14, and the annular groove 15 is a flat land portion 12.

[0060] Moreover, the annular groove 15 is formed deeper than the dynamic pressure groove 13 and the fluid recovery groove 14. Additionally, preferably, the annular groove 15 has a depth of 10 times or more that of the dynamic pressure groove 13 and the fluid recovery groove 14.

[0061] Fluid recovery grooves 14 are circumferentially and equally disposed on the outer diameter side of the annular groove 15 (for example, 16 in this embodiment). The first groove portion 141 of the fluid recovery groove 14 described later and the second groove portion 142 of the fluid recovery groove 14 disposed on the relatively rotating upstream side partially overlap in the radial direction.

[0062] The fluid recovery groove 14 is composed of a first groove portion 141 and a second groove portion 142. The fluid recovery groove 14 is formed, for example, to have the same depth as the dynamic pressure groove 13, and the cross section of the fluid recovery groove 14 has a rectangular shape. Additionally, the depth of the fluid recovery groove 14 may also be different from the depth of the dynamic pressure groove 13.

[0063] The first groove portion 141 is inclined toward the inner diameter side from the upstream side in the rotation direction of the rotary seal ring 20 toward the downstream side in the rotation direction, that is, it extends in an arc shape circumferentially from the relatively rotating upstream side to the downstream side. The circumferential component of the first groove portion 141 in this embodiment is larger than the radial component. In addition, the first groove portion 141 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. The same applies to the radial direction, as long as it includes at least a radial component.

[0064] The groove width of the first groove portion 141 gradually widens from the upstream side in the rotation direction of the rotary seal ring 20 toward the downstream side in the rotation direction. The end portion 141a on the upstream side in the rotation direction of the rotary seal ring 20 of the first groove portion 141 is closed. The end portion on the downstream side in the rotation direction of the rotary seal ring 20 of the first groove portion 141 communicates with the second groove portion 142.

[0065] The second groove portion 142 inclines from the end portion on the downstream side in the rotation direction of the rotary seal ring 20 of the first groove portion 141 toward the downstream side in the rotation direction of the rotary seal ring 20 and extends substantially linearly toward the inner diameter side. In other words, the second groove portion 142 inclines in a direction opposite to that of the hydrodynamic groove 13.

[0066] In other words, the second groove portion 142 bends at an obtuse angle from the first groove portion 141 and extends toward the annular groove 15. A corner portion 143 having a bent shape as a pressure generating portion, i.e., a bent portion, is formed between the first groove portion 141 and the second groove portion 142. In other words, the corner portion 143 is a portion where the curvature of the fluid recovery groove 14 changes, and is a bent portion on the downstream side in the relative rotation direction of the fluid recovery groove 14. The corner portion 143 is provided at the terminal of the first groove portion 141. In addition, the corner portion between the first groove portion 141 and the second groove portion 142 may be formed in a bent manner.

[0067] In the second groove portion 142 of the present embodiment, the radial component is larger than the circumferential component. In addition, the second groove portion 142 only needs to have at least a radial component. That is, the circumferential component of the second groove portion 142 is smaller than the circumferential component of the first groove portion 141, and the radial component of the second groove portion 142 is larger than the radial component of the first groove portion 141.

[0068] The end portion 142a on the downstream side in the rotation direction of the rotary seal ring 20 of the second groove portion 142 communicates with the annular groove 15.

[0069] Next, the functions of the hydrodynamic groove 13 and the fluid recovery groove 14 when the stationary seal ring 10 and the rotary seal ring 20 rotate relative to each other will be briefly described.

[0070] As Figure 3 shown, when the rotary seal ring 20 rotates relative to the stationary seal ring 10, the fluid in the hydrodynamic groove 13, the fluid recovery groove 14, and the annular groove 15 moves following the relative rotation of the rotary seal ring 20.

[0071] Specifically, in the hydrodynamic groove 13, as Figure 3 indicated by the black arrow, the sealed fluid F moves from the inner diameter end 13a of the hydrodynamic groove 13 toward the outer diameter end 13b. Thereby, a positive pressure is generated at the outer diameter end 13b and in its vicinity. And the sealed fluid F is supplied to the hydrodynamic groove 13 from the inner space S1 via the inner diameter end 13a at any time.

[0072] A part of the sealed fluid F discharged from the outer diameter end 13b and its vicinity to between the sliding surfaces 11 and 21 flows into the annular groove 15.

[0073] On the other hand, in the fluid recovery groove 14, as Figure 3 shown by the white arrow in, the atmosphere A moves from the end 141a of the fluid recovery groove 14 toward the end 142a. As a result, a positive pressure is slightly generated at the corner 143 of the fluid recovery groove 14 and its vicinity.

[0074] A part of the sealed fluid F discharged from the corner 143 of the fluid recovery groove 14 to between the sliding surfaces 11 and 21 flows into the fluid recovery groove 14 adjacent in the circumferential direction, and another part flows into the annular groove 15.

[0075] Moreover, the pressure in the region closer to the inner space S1 than the annular groove 15 is higher than the pressure in the region closer to the outer space S2 than the annular groove 15. Therefore, sometimes a part of the sealed fluid F crosses the annular groove 15 and leaks to the inner space S1 side.

[0076] A part of the sealed fluid F flowing out toward the outer space S2 across the annular groove 15 is sucked into the fluid recovery groove 14 and returns to the annular groove 15 from the end 142a, and another part is restricted from moving toward the outer space S2 by the positive pressure generated at the corner 143 and its vicinity. Therefore, leakage of the sealed fluid F to the outer space S2 is prevented.

[0077] As described above, it is possible to generate a positive pressure on the inner diameter side and the outer diameter side of the annular groove 15 sandwiching the sliding surface 11 by the outer diameter end 13b of each hydrodynamic groove 13 and the corner 143 of each fluid recovery groove 14. Moreover, each hydrodynamic groove 13 and each fluid recovery groove 14 are arranged uniformly in the circumferential direction. Thereby, it is possible to generate a positive pressure evenly in the circumferential direction on the inner diameter side and the outer diameter side of the annular groove 15 sandwiching the sliding surface 11, and it is possible to improve the floating balance between the stationary seal ring 10 and the rotating seal ring 20. Therefore, the lubricity between the sliding surfaces 11 and 21 can be improved.

[0078] Moreover, the region of the sliding surface 11 where the hydrodynamic groove 13 is provided and the region where the fluid recovery groove 14 is provided are divided by the annular groove 15 over the entire circumference in the circumferential direction. Therefore, it is possible to suppress the interference between the positive pressure generated in the hydrodynamic groove 13 and the positive pressure generated in the fluid recovery groove 14.

[0079] Moreover, the fluid recovery groove 14 has a corner 143 where the first groove portion 141 and the second groove portion 142 are bent. Thereby, a positive pressure can be generated at the corner 143 when the stationary seal ring 10 and the rotating seal ring 20 rotate relative to each other.

[0080] Moreover, the circumferentially extending first groove portion 141 can recover the sealed fluid F flowing out to a position on the outer diameter side of the annular groove 15 within a relatively large range in the circumferential direction. Further, the radially extending second groove portion 142 can guide the sealed fluid F recovered by the first groove portion 141 to the annular groove 15.

[0081] Moreover, the end portion 142a of the second groove portion 142 communicates with the annular groove 15. Accordingly, a positive pressure is not generated at the end portion 142a of the second groove portion 142 of the fluid recovery groove 14, and thus the positive pressure generated at the outer diameter end 13b of the hydrodynamic groove 13 is not affected.

[0082] Moreover, since the fluid in the fluid recovery groove 14 can always be discharged to the annular groove 15, the pumping function of the fluid recovery groove 14 is not reduced, and the sealed fluid F can be reliably recovered.

[0083] Moreover, since the annular groove 15 is deeper than the fluid recovery groove 14, it is easy to recover the sealed fluid F flowing out between the sliding surfaces 11 and 12 into the annular groove 15. Accordingly, it is possible to prevent the positive pressure in the region of the sliding surface 11 on the inner space S1 side of the annular groove 15 from becoming excessive.

[0084] Further, since the pressure in the fluid recovery groove 14 is opened by means of the annular groove 15, the reduction in the pumping function of the fluid recovery groove 14 can be further suppressed.

[0085] Moreover, since the hydrodynamic groove 13 communicates with the inner space S1 side, the sealed fluid F in the hydrodynamic groove 13 does not run dry, and the hydrodynamic effect is high.

[0086] Moreover, since the hydrodynamic groove 13 does not communicate with the annular groove 15, it is not affected by the pressure fluctuation in the annular groove 15, and a positive pressure can be stably generated.

[0087] Moreover, the first groove portion 141 becomes wider from the upstream side in the rotation direction of the rotary seal ring 20 toward the downstream side in the rotation direction. Accordingly, it is easy for a negative pressure to be relatively generated in the first groove portion 141 of the fluid recovery groove 14.

[0088] Moreover, the end portion 141a of the first groove portion 141 is disposed near the outer diameter side of the corner portion 143 of the fluid recovery groove 14 on the upstream side in the rotation direction of the rotary seal ring 20. Accordingly, the sealed fluid F flowing out from the corner portion 143 and its vicinity between the sliding surfaces 11 and 21 is recovered into the first groove portion 141 of the fluid recovery groove 14 on the downstream side in the rotation direction.

[0089] Moreover, the more upstream the rotation direction of the rotary seal ring 20 is, the greater the negative pressure relatively generated in the first groove portion 141. Therefore, the first groove portion 141 can recover the sealed fluid F that has moved to a position closer to the outer space S2 side than the fluid recovery groove 14 located upstream of the rotary seal ring 20 in the rotation direction.

[0090] In addition, in the present embodiment, an example is shown in which the end portion 142a of the second groove portion 142 communicates with the annular groove 15, but it is not limited thereto. The end portion of the second groove portion may also be a closed end portion, that is, not communicate with the annular groove. In this case, a positive pressure can be generated at the closed end portion of the second groove portion and its vicinity, so the pressure balance is good. And the fluid flowing out from the closed end portion of the second groove portion to the sliding surface is recovered into the annular groove.

[0091] In addition, in the present embodiment, an example is shown in which the annular groove 15 is provided between the hydrodynamic groove 13 and the fluid recovery groove 14, but it is not limited thereto. For example, the surrounding groove may also be C-shaped, or may be a circular arc-shaped groove provided in a plurality along the circumferential direction. The surrounding groove only needs to be provided at least between the hydrodynamic generation portion of the hydrodynamic groove and the pressure generation portion of the fluid recovery.

[0092] In addition, in the present embodiment, an example is shown in which the annular groove 15 is formed deeper than the hydrodynamic groove 13 and the fluid recovery groove 14, but it may also be the same depth as the hydrodynamic groove 13 and the fluid recovery groove 14.

[0093] In addition, in the present embodiment, an example is shown in which the cross section of the fluid recovery groove 14 is rectangular, but the cross-sectional shape may also be U-shaped, semicircular, or triangular, and can be appropriately changed. The same applies to the hydrodynamic groove 13.

[0094] In addition, in the present embodiment, an example is shown in which the corner portion 143 of the fluid recovery groove 14 as a bent portion functions as a pressure generation portion, but the pressure generation portion may also be provided at a portion different from the bent portion of the fluid recovery groove 14.

[0095] In addition, in the present embodiment, the outer diameter ends 13b of the respective hydrodynamic grooves 13 are configured to be arranged on the same circle, but it is not limited thereto. The positions of the outer diameter ends of the respective hydrodynamic grooves can be appropriately changed. For example, the outer diameter ends of the respective hydrodynamic grooves may also be arranged such that they gradually move from the outer diameter side to the inner diameter side from the upstream side to the downstream side in the relative rotation direction. With such a structure, the stationary seal ring 10 generates hydrodynamic pressure at different positions in the radial direction, and the floating balance with the rotary seal ring 20 can be further improved.

[0096] Embodiment 2

[0097] Next, refer to Figure 4A description will be given of the sliding member of Example 2. In addition, redundant structural descriptions of the same structures as those in the foregoing Example 1 will be omitted.

[0098] As Figure 4 shown, the stationary seal ring 210 of the present Example 2 has a communication groove 216 that communicates the annular groove 215 with the inner space S1. A plurality of (for example, four in the present example) communication grooves 216 are provided along the circumferential direction.

[0099] Thereby, the positive pressure generated in the hydrodynamic pressure generation groove 213 can be reduced to the pressure in the inner space S1 via the annular groove 215 and the communication groove 216. Therefore, it is possible to prevent the positive pressure in the region of the sliding surface 211 on the inner space S1 side from becoming too high compared to the annular groove 215. Thereby, it is possible to make it difficult for the sealed fluid F to enter the region of the sliding surface 211 on the outer space S2 side compared to the annular groove 215, and therefore it is possible to suppress the leakage of the sealed fluid F to the outer space S2 side.

[0100] In addition, in the present Example 2, the manner in which the communication groove 216 communicates with the inner space S1 is illustrated, but as long as it extends near the inner space S1, the inner diameter end of the communication groove may also be closed, that is, not communicate with the inner space S1.

[0101] Example 3

[0102] Next, a description will be given of the sliding member of Example 3 with reference to Figure 5 In addition, redundant structural descriptions of the same structures as those in the foregoing Example 1 will be omitted.

[0103] As Figure 5 shown, in the stationary seal ring 310 of the present Example 3, the shape of the fluid recovery groove 314 is different from the shape of the fluid recovery groove 14 of Example 1.

[0104] The second groove portion 342 of the fluid recovery groove 314 of the present Example 3 extends in an arc shape protruding toward the outer diameter side from the end portion on the downstream side in the rotation direction of the rotary seal ring 20 of the first groove portion 341 toward the annular groove 315. Thereby, the corner portion 343 of the fluid recovery groove 314 is formed more gently than the corner portion 143 of Example 1. That is, the corner portion 343 has a curved shape. In other words, the corner portion 343 is a portion where the curvature of the fluid recovery groove 314 changes, and is the curved portion on the downstream side of the fluid recovery groove 314 with respect to the relative rotation direction.

[0105] Thereby, compared with the fluid recovery groove 14 of Example 1, the positive pressure generated at the corner portion 343 of the fluid recovery groove 314 of the present Example 3 is suppressed, and it is easy for the recovered fluid to return to the annular groove 315.

[0106] Example 4

[0107] Next, with reference toFigure 6 The sliding member of Example 4 will be described. In addition, the description of the repeated structures that are the same as those in the foregoing Example 1 will be omitted.

[0108] As Figure 6 shown, in the stationary seal ring 410 of the present Example 4, the shape of the fluid recovery groove 414 is different from the shape of the fluid recovery groove 14 of Example 1.

[0109] In the fluid recovery groove 414 of the present Example 4, the second groove portion 442 extends in an arc shape from the end portion on the downstream side in the rotation direction of the rotary seal ring 20 of the first groove portion 441 toward the annular groove 415 so as to protrude toward the inner diameter side. Thus, the corner portion 443 of the fluid recovery groove 414 is formed sharper than the corner portion 143 of Example 1.

[0110] As a result, compared with the fluid recovery groove 14 of Example 1, the positive pressure generated at the corner portion 443 of the fluid recovery groove 414 of the present Example 4 is higher, and the flow rate returning to the annular groove 415 is smaller.

[0111] Example 5

[0112] Next, with reference to Figure 7 the sliding member of Example 5 will be described. In addition, the description of the repeated structures that are the same as those in the foregoing Example 1 will be omitted.

[0113] As Figure 7 shown, in the stationary seal ring 510 of the present Example 5, the shape of the fluid recovery groove 514 is different from the shape of the fluid recovery groove 14 of Example 1.

[0114] In the fluid recovery groove 514 of the present Example 5, the first groove portion 541 and the second groove portion 542 are radially separated by the land portion 512. That is, the first groove portion 541 and the second groove portion 542 are not connected. The end portion 541b on the relatively downstream side in the rotation direction of the first groove portion 541 is the circumferential end portion on the relatively downstream side in the rotation direction of the fluid recovery groove 514.

[0115] As a result, a positive pressure is generated at the end portion 541b on the relatively downstream side in the rotation direction of the first groove portion 541 and in the vicinity thereof, and a part of the fluid flowing out from the end portion 541b to between the sliding surfaces can be recovered by the second groove portion 542. And another part of the fluid flowing out from the end portion 541b to between the sliding surfaces is recovered by the first groove portion 541 of the fluid recovery groove 514 on the relatively downstream side in the rotation direction.

[0116] Example 6

[0117] Next, with reference to Figure 8 the sliding member of Example 6 will be described. In addition, the description of the repeated structures that are the same as those in the foregoing Example 1 will be omitted.

[0118] As Figure 8 shown, the fluid recovery groove 614 of the stationary seal ring 610 in the sixth embodiment has a third groove portion 644 that extends circumferentially from the inner diameter end of the second groove portion 642. That is, when viewed axially, the fluid recovery groove 614 is formed by the first groove portion 641, the second groove portion 642, and the third groove portion 644 into a substantially reverse Z shape. The end portion 644a on the relatively rotation downstream side of the third groove portion 644 is the circumferential end portion on the relatively rotation downstream side of the fluid recovery groove 514. In addition, the third groove portion 644 is disposed on the inner diameter side of the first groove portion 641 of the fluid recovery groove 614 on the relatively rotation downstream side.

[0119] A part of the fluid flowing out from the corner portion 643 of the fluid recovery groove 614 to between the sliding surfaces is recovered into the third groove portion 644, and another part is recovered into the first groove portion 641 of the adjacent fluid recovery groove 614. And, the fluid moving toward the inner diameter side along the second groove portion 642 flows out from the end portion 644a of the third groove portion 644 to between the sliding surfaces. Thereby, a positive pressure is generated at the end portion 644a and its vicinity.

[0120] And, a part of the fluid flowing out from the end portion 644a to between the sliding surfaces is recovered into the annular groove 615, and another part is recovered into the first groove portion 641 of the adjacent fluid recovery groove 614.

[0121] Embodiment 7

[0122] Next, the sliding member of the seventh embodiment will be described with reference to Figure 9 In addition, the description of the structure that is the same as that of the foregoing sixth embodiment will be omitted.

[0123] As Figure 9 shown, in the stationary seal ring 710 of the seventh embodiment, the second groove portion 742 of the fluid recovery groove 714 extends in an arc shape protruding toward the outer diameter side from the end portion on the rotation downstream side of the rotation seal ring 20 of the first groove portion 741. Thereby, it flows out from the end portion 744a of the third groove portion 744 to between the sliding surfaces, so a positive pressure is generated at the end portion 744a and its vicinity. Therefore, regarding the positive pressure generation portions on the leakage side (outer diameter side) relative to the annular groove 715, the corner portion 743 on the leakage side and the end portion 744a on the annular groove 715 side alternately exist in the circumferential direction. In addition, there is a dynamic pressure groove 713 at a position on the sealed fluid side (inner diameter side) relative to the annular groove 715. Therefore, the positive pressure generation effect is evenly improved in the radial direction, the floating balance between the stationary seal ring 10 and the rotation seal ring 20 can be further improved, and the lubricity between the sliding surfaces can be improved.

[0124] Moreover, the second groove portion 742 extends in an arc shape so as to protrude toward the outer diameter side. Accordingly, compared with the fluid recovery groove 614 of the sixth embodiment, the positive pressure generated at the corner portion 743 of the fluid recovery groove 714 is suppressed, and the recovered fluid can easily return to the annular groove 715.

[0125] Embodiment 8

[0126] Next, a sliding member according to the eighth embodiment will be described. In addition, redundant structural descriptions of the same structures as those in the aforementioned sixth embodiment are omitted. Figure 10

[0127] Figure 10 As Figure 10 shown, in the stationary seal ring 810 of the eighth embodiment, the second groove portion 842 of the fluid recovery groove 814 extends in an arc shape so as to protrude toward the inner diameter side from the end portion on the downstream side in the rotation direction of the rotary seal ring 20 of the first groove portion 841 toward the third groove portion 844. Accordingly, the fluid flows out from the end portion 844a of the third groove portion 844 between the sliding surfaces, and thus positive pressure is generated at the end portion 844a and its vicinity. Therefore, with respect to the positive pressure generation portions on the leakage side (outer diameter side) with respect to the annular groove 815, the leakage side corner portion 843 and the end portion 844a on the annular groove 815 side alternately exist in the circumferential direction. In addition, a dynamic pressure groove 813 exists at a position on the sealed fluid side (inner diameter side) with respect to the annular groove 815. Therefore, the positive pressure generation effect is equally improved in the radial direction, and the floating balance between the stationary seal ring 10 and the rotary seal ring 20 can be further improved, and the lubricity between the sliding surfaces can be improved.

[0128] Moreover, the second groove portion 842 extends in an arc shape so as to protrude toward the inner diameter side. Accordingly, the corner portion 843 of the fluid recovery groove 814 is formed sharper than the corner portion 643 of the sixth embodiment. Accordingly, compared with the fluid recovery groove 614 of the sixth embodiment, the positive pressure generated at the corner portion 843 becomes higher, and the flow rate returning to the annular groove 815 becomes smaller.

[0129] Embodiment 9

[0130] Next, a sliding member according to the ninth embodiment will be described. In addition, redundant structural descriptions of the same structures as those in the aforementioned ninth embodiment are omitted. Figure 11

[0131] Figure 11

[0132] As shown, a plurality of inclined grooves 1016 (for example, four in the ninth embodiment) are provided between the first groove portion 1041 of the fluid recovery groove 1014 of the stationary seal ring 1010 of the ninth embodiment and the third groove portion 1044' of the fluid recovery groove 1014' adjacent to the upstream side in the circumferential direction.

[0132] The inclined groove 1016 extends obliquely from the first groove portion 1041 toward the third groove portion 1044' on the relatively rotation downstream side. Further, the inclined groove 1016 is formed shallower than the fluid recovery groove 1014. Alternatively, the inclined groove 1016 may have the same depth as the fluid recovery groove 1014.

[0133] Thereby, a part of the fluid recovered by the first groove portion 1041 can be introduced into the third groove portion 1044', contributing to the generation of positive pressure in the third groove portion 1044'.

[0134] Example 10

[0135] Next, Figure 12 the sliding member of Example 10 will be described. In addition, the description of the structure that is the same as that of the foregoing Example 1 will be omitted.

[0136] As Figure 12 shown, in the stationary seal ring 1110 of the present Example 10, the fluid recovery groove 1114 is different from the fluid recovery groove 14 of the foregoing Example 1.

[0137] On the inner diameter side of the first groove portion 1141 of the fluid recovery groove 1114, a plurality of inclined grooves 1117 (for example, six in the present Example 9) that extend linearly obliquely toward the inner diameter side on the relatively rotation downstream side are provided. The outer diameter ends of these inclined grooves 1117 communicate with the first groove portion 1141, and the inner diameter ends are closed ends 1117a.

[0138] The second groove portion 1142 and the inclined grooves 1117 are arranged on the inner diameter side of the corner portion 1143 of the fluid recovery groove 1114. Thereby, positive pressure can be generated by the corner portion 1143, the closed ends 1117a of the respective inclined grooves 1117, and the hydrodynamic pressure grooves 1113.

[0139] Example 11

[0140] Next, Figure 13 the sliding member of Example 11 will be described. In addition, the description of the structure that is the same as that of the foregoing Example 10 will be omitted.

[0141] As Figure 13 shown, the second groove portion 1242 and the inclined grooves 1217 of the stationary seal ring 1210 of the present Example 11 extend in an arc shape so as to protrude toward the outer diameter side. Thereby, the positive pressure generated at the corner portion 1243 is suppressed, and it becomes easy for the recovered fluid to return to the annular groove 1215.

[0142] Example 12

[0143] Next, Figure 14The sliding member of Example 12 will be described. In addition, the description of the repeated structures that are the same as those of the foregoing Example 10 will be omitted.

[0144] As Figure 14 shown, the second groove portion 1342 and the inclined groove 1317 of the stationary seal ring 1310 of the present Example 12 extend in an arc shape so as to protrude toward the inner diameter side. Here, it extends in an arc shape so as to protrude toward the inner diameter side from the end portion on the downstream side in the rotation direction of the rotary seal ring 20 of the first groove portion 1341 toward the annular groove 1315. As a result, the corner portion 1343 is formed sharper than in Example 11. Accordingly, the positive pressure generated at the corner portion 1343 is higher than that of the fluid recovery groove 1114 of Example 11, and the flow rate returning to the annular groove 1315 becomes smaller.

[0145] Example 13

[0146] Next, Figure 15 the sliding member of Example 13 will be described. In addition, the description of the repeated structures that are the same as those of the foregoing Example 1 will be omitted.

[0147] On the sliding surface 1511 of the stationary seal ring 1510 of the present Example 13, a plurality of fluid recovery grooves 1514, a plurality of hydrodynamic grooves 1513, and an annular groove 1515 are formed.

[0148] The end portion 1541c on the upstream side in the rotation direction of the rotary seal ring 20 of each first groove portion 1541 overlaps with the corner portion 1543 of the fluid recovery groove 1514 adjacent to the upstream side in the rotation direction of the rotary seal ring 20 in the circumferential direction. In addition, in the present invention, the case where they are arranged at overlapping positions when viewed in the circumferential direction is expressed as overlapping in the circumferential direction. Similarly, in the present invention, the case where they are arranged at overlapping positions when viewed in the radial direction is expressed as overlapping in the radial direction.

[0149] And each first groove portion 1541 extends linearly. Therefore, by extending each first groove portion 1541 in the circumferential direction, a polygon can be drawn. And the number of the first groove portions 1541 can be freely changed, and in this case, a polygon having the number of sides can be drawn.

[0150] Accordingly, the first groove portion 1541 can efficiently recover the sealed fluid F flowing out between the sliding surfaces 1511 and 21 from the corner portion 1543 of the first groove portion 1541 adjacent to the upstream side in the rotation direction of the rotary seal ring 20.

[0151] Example 14

[0152] Next, Figure 16 the sliding member of Example 14 will be described. In addition, the description of the repeated structures that are the same as those of the foregoing Example 1 will be omitted.

[0153] On the sliding surface 1611 of the stationary seal ring 1610 of the present Embodiment 14, a plurality of fluid recovery grooves 1614, a plurality of hydrodynamic grooves 1613, and an annular groove 1615 are formed.

[0154] The first groove portions 1641 of the respective fluid recovery grooves 1614 are formed in an arc shape with the same curvature and are arranged on the same circumference. Moreover, the curvature of the first groove portions 1641 is substantially the same as the curvature of the stationary seal ring 1610. Further, by extending each of the first groove portions 1641 in the circumferential direction, a circle can be depicted.

[0155] Moreover, the upstream end 1641a on the upstream side in the rotational direction of the rotary seal ring 20 of each of the first groove portions 1641 overlaps with the corner portion 1643 of the fluid recovery groove 1614 adjacent to the upstream side in the rotational direction of the rotary seal ring 20 in the circumferential direction.

[0156] Accordingly, the first groove portions 1641 can guide the fluid F to be sealed along the rotational direction. Also, the fluid F that has flowed out from the corner portion 1643 of the fluid recovery groove 1614 adjacent to the upstream side in the rotational direction of the rotary seal ring 20 between the sliding surfaces 1611 and 21 also easily moves along the rotational direction. Thereby, the stationary seal ring 1610 can recover the fluid F to be sealed without omission.

[0157] Embodiment 15

[0158] Next, a sliding member of Embodiment 15 will be described with reference to Figure 17 The description of the structure that is the same as that of the aforementioned Embodiment 1 will be omitted.

[0159] On the sliding surface 1711 of the stationary seal ring 1710 of the present Embodiment 15, a plurality of fluid recovery grooves 1714, a plurality of hydrodynamic grooves 1713, and an annular groove 1715 are formed.

[0160] The fluid recovery groove 1714 communicates with the second groove portion 1742 at a position separated from the end portion 1741b, which is a pressure generation portion, on the relatively rotation downstream side of the rotary seal ring 20 of the first groove portion 1741 toward the relatively rotation upstream side.

[0161] Accordingly, a positive pressure can be generated at the end portion 1741b of the first groove portion 1741 and in its vicinity. Also, another part of the fluid that has flowed out from the end portion 1741b between the sliding surfaces is recovered by the first groove portion 1741 of the fluid recovery groove 1714 on the relatively rotation downstream side.

[0162] Embodiment 16

[0163] Next, a reference will be made to Figure 18A description is given of the sliding member of Embodiment 16. In addition, the description of the structure that is the same as that of the aforementioned Embodiment 1 is omitted.

[0164] On the sliding surface 1811 of the stationary seal ring 1810 of the present Embodiment 16, a plurality of fluid recovery grooves 1814, a plurality of hydrodynamic grooves 1813, and an annular groove 1815 are formed.

[0165] The fluid recovery grooves 1814 are formed in an arc shape protruding toward the outer diameter side with a substantially constant curvature that is smaller than the curvature of the corner portion 343 of the aforementioned Embodiment 2. The end portion 1814a on the downstream side in the rotation direction of the rotary seal ring 20 of the fluid recovery groove 1814 communicates with the annular groove 1815. The end portion 1814b on the upstream side in the rotation direction of the rotary seal ring 20 of the fluid recovery groove 1814 is closed.

[0166] Moreover, the fluid recovery groove 1814 has a relatively downstream-side curved portion 1814c that extends from its circumferential center toward the end portion 1814a toward the inner diameter side and the downstream side in the rotation direction of the rotary seal ring 20. A positive pressure is slightly generated in the curved portion 1814c. Thus, the curved portion 1814c functions as a pressure generation portion of the fluid recovery groove 1814.

[0167] Accordingly, compared with the fluid recovery groove 212 of Embodiment 2, the positive pressure generated in the curved portion 1814c of the fluid recovery groove 1814 of the present embodiment is suppressed, and it is easy to discharge the recovered fluid from the end portion 1814a to the annular groove 1815.

[0168] Embodiment 17

[0169] Next, refer to Figure 19 A description is given of the sliding member of Embodiment 17. In addition, the description of the structure that is the same as that of the aforementioned Embodiment 1 is omitted.

[0170] The mechanical seal using the stationary seal ring 1410 of the present Embodiment 17 is an inside-type mechanical seal that seals the fluid F to be sealed existing on the outer space S12 side of the sliding surfaces 1411 and 21 and the inner space S11 communicates with the atmosphere A.

[0171] On the sliding surface 1411, a plurality of fluid recovery grooves 1414, a plurality of hydrodynamic grooves 1413, and an annular groove 1415 are formed.

[0172] The fluid recovery grooves 1414 and the hydrodynamic grooves 1413 have a shape obtained by substantially turning the fluid recovery grooves 14 and the hydrodynamic grooves 13 of the aforementioned Embodiment 1 in the radial direction.

[0173] Thus, as indicated by the solid-line arrow, by rotating the rotary seal ring 20, a positive pressure is generated at the corner 1443 of the fluid recovery groove 1414 and in its vicinity. Also, a positive pressure is generated at the outer diameter end 1413b of the hydrodynamic pressure groove 1413 and in its vicinity.

[0174] In this way, 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 space is on the inner diameter side of the sliding surface.

[0175] As described above, the embodiments of the present invention have been described with reference to the drawings. However, 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.

[0176] For example, in the foregoing Embodiments 1 to 16, as the sliding member, a mechanical seal for an automobile has been described as an example, but it may also be other mechanical seals such as those for general industrial machinery. Moreover, it is not limited to mechanical seals, and it may also be a sliding member other than mechanical seals such as a sliding bearing.

[0177] Also, in the foregoing Embodiments 1 to 16, the case where the fluid to be sealed is a high-pressure liquid has been described. However, it is not limited thereto, and it may also be a gas or a low-pressure liquid, or it may be a mist mixture of liquid and gas.

[0178] Also, in the foregoing Embodiments 1 to 16, the case where the fluid on the leakage space side is the atmosphere as a low-pressure gas has been described. However, it is not limited thereto, and it may also be a liquid or a high-pressure gas, or it may be a mist mixture of liquid and gas.

[0179] Also, in the foregoing Embodiments 1 to 16, the fluid space to be sealed side has been described as the high-pressure side and the leakage space side as the low-pressure side. However, it may also be that the fluid space to be sealed side is the low-pressure side and the leakage space side is the high-pressure side, or it may be that the fluid space to be sealed side and the leakage space side are at substantially the same pressure.

[0180] Also, in the foregoing Embodiments 1 to 16, 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 rotary seal ring.

[0181] Reference Numeral Explanation

[0182] 10: Stationary seal ring (sliding part); 11: Sliding surface; 13: Hydrodynamic groove (hydrodynamic generation groove); 13b: Outer diameter end (hydrodynamic generation part); 14: Fluid recovery groove (fluid recovery groove); 15: Annular groove (surrounding groove); 20: Rotating seal ring (sliding part); 21: Sliding surface; 141: First groove part; 142: Second groove part; 143: Corner part (pressure generation part); A: Atmosphere (fluid on the leakage space side); F: Fluid to be sealed; S1: Inner space (fluid to be sealed space); S2: Outer space (leakage space).

Claims

1. A sliding member, in which 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, wherein, at least on any one of the sliding surfaces there is provided: a hydrodynamic generation groove; a fluid recovery groove which is provided at a position closer to the leakage space side than the hydrodynamic generation groove and has at least one pressure generation part as a circumferential end part, a bent part or a folded part; and a surrounding groove which is provided between the hydrodynamic generation groove and the fluid recovery groove in the radial direction and extends in the circumferential direction.

2. The sliding member according to claim 1, wherein, the fluid recovery groove has a first groove part extending in the circumferential direction and a second groove part which bends or folds from the first groove part and extends toward the surrounding groove, and the pressure generation part is a bent part between the first groove part and the second groove part.

3. The sliding member according to claim 1, wherein, the surrounding groove is annular.

4. The sliding member according to claim 1, wherein, the fluid recovery groove communicates with the surrounding groove.

5. The sliding member according to claim 1, wherein, the sliding member has a communication groove which communicates the surrounding groove with the fluid space to be sealed.

6. The sliding member according to any one of claims 1 to 5, wherein, the surrounding groove is deeper than the fluid recovery groove.

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

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

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