Sliding component

Abstract

The present invention provides a sliding component capable of enhancing sealability.　Provided are sliding components 10, 20 in which a pair of sliding surfaces 11, 21 rotate relative to each other and which divide a space between a sealed fluid space S1 and a leakage space S2, wherein: at least one of the sliding surfaces, e.g., the sliding surface 11 is provided with dynamic pressure generating grooves 13, and an endless annular groove 15 that is located closer to the leakage space S2 side than the dynamic pressure generating grooves 13 and that extends in the circumferential direction; the one sliding surface 11 or the other sliding surface 21 is provided with a pumping groove 14 provided closer to the sealed fluid space S1 side than the annular groove 15; and an end 14b of the pumping groove 14 that is positioned on the opposite side in the radial direction from the annular groove 15 and the dynamic pressure generating grooves 13 overlap each other in the circumferential direction.

Description

Sliding parts

[0001] The present invention relates to a sliding part that rotates relative to another sliding part, such as a sliding part used in a shaft sealing device that seals the rotating shaft of a rotating machine in an automobile, general industrial machine, or other sealing field, or a sliding part used in a bearing of a machine in an automobile, general industrial machine, or other bearing field.

[0002] Mechanical seals, for example, are shaft sealing devices that prevent leakage of sealed fluids and are equipped with a pair of annular sliding components that rotate relative to one another and have sliding surfaces that slide against each other. In recent years, there has been a demand for reducing the energy lost due to sliding in such mechanical seals, for environmental reasons.

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

[0004] As the rotary seal ring rotates, the dimples guide the sealed fluid from the upstream side in the direction of rotation in the cavitation formation region to the downstream side in the direction of rotation in the positive pressure generation region, generating positive pressure at the downstream end. This positive pressure causes the mating sliding surfaces to float, introducing the sealed fluid between the sliding surfaces, thereby reducing energy loss due to sliding. In addition, the negative pressure generated at the upstream end in the direction of rotation in the cavitation formation region allows the dimples to recover the sealed fluid that has migrated to the low-pressure space.

[0005] Patent No. 6058018 (pages 8 and 9, Figure 4)

[0006] In the sliding component of Patent Document 1, the positive pressure generating regions of the dimples are positioned close to the sealed fluid space, allowing a portion of the sealed fluid to be recovered to the high-pressure fluid side. However, the cavitation generating regions of the dimples are positioned scattered in the circumferential direction. This causes the negative pressure generated in the circumferential direction between the sliding surfaces to be uneven, which may impair sealing performance.

[0007] The present invention has been made in view of these problems, and has as its object to provide a sliding component that can improve sealing performance.

[0008] To solve the above problems, the present invention provides a sliding component having a pair of sliding surfaces that rotate relative to each other and partition a sealed fluid space and a leakage space, wherein at least one of the sliding surfaces includes a dynamic pressure generating groove and an endless annular groove that is located closer to the leakage space than the dynamic pressure generating groove and extends circumferentially, and either one sliding surface or the other sliding surface includes a pumping groove that is located closer to the sealed fluid space than the annular groove, and an end of the pumping groove that is located radially opposite the annular groove overlaps with the dynamic pressure generating groove in the circumferential direction. This pumping groove allows fluid to flow from the annular groove toward the sealed fluid space, making it easier for the annular groove to become relatively negative pressure. This allows fluid that has leaked between the sliding surfaces to be collected over the entire circumference by the annular groove, thereby improving sealing performance. Furthermore, since the pumping groove and the dynamic pressure generating groove overlap in the circumferential direction, the dynamic pressure generating groove can be positioned close to the annular groove, allowing fluid to be supplied from the dynamic pressure generating groove to the annular groove, thereby preventing the annular groove from becoming excessively poorly lubricated.

[0009] The dynamic pressure generating groove may be in communication with the sealed fluid space, thereby improving the dynamic pressure generating effect of the dynamic pressure generating groove.

[0010] The pumping groove may be in communication with the annular groove, which allows fluid to flow smoothly from the annular groove to the pumping groove, making it easier to generate a relative negative pressure in the annular groove.

[0011] A plurality of the pumping grooves may be arranged in the circumferential direction, whereby fluid can be discharged between the sliding surfaces from a plurality of locations in the circumferential direction of the annular groove, thereby generating a relative negative pressure in a well-balanced manner over the circumferential direction of the annular groove.

[0012] The annular groove may be a circular ring, which allows a relative negative pressure to be generated in a well-balanced manner around the circumference of the annular groove.

[0013] The pumping groove may extend radially toward the sealed fluid space, thereby pushing the fluid toward the sealed fluid space, thereby reducing leakage.

[0014] Fig. 1 is a longitudinal sectional view showing an example of a mechanical seal in a first embodiment according to the present invention. Fig. 2 is a view of the sliding surface of a stationary seal ring in the first embodiment, as viewed from the axial direction. Fig. 3 is a partially enlarged view of Fig. 2. Fig. 4 is a partially enlarged view of the sliding surface of a stationary seal ring in a second embodiment according to the present invention, as viewed from the axial direction. Fig. 5 is a partially enlarged view of the sliding surface of a stationary seal ring in a third embodiment according to the present invention, as viewed from the axial direction. Fig. 6 is a partially enlarged view of the sliding surface of a stationary seal ring in a fourth embodiment according to the present invention, as viewed from the axial direction. Fig. 7 is a partially enlarged view of the sliding surface of a stationary seal ring in a fifth embodiment according to the present invention, as viewed from the axial direction. Fig. 8 is a partially enlarged view of the sliding surface of a stationary seal ring in a sixth embodiment according to the present invention, as viewed from the axial direction.

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sliding element according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0016] A sliding element according to a first embodiment will be described with reference to Figures 1 to 3. In this embodiment, the sliding element will be described as being applied to a mechanical seal.

[0017] In addition, the inner space S1 of the mechanical seal contains a sealed fluid F as a first fluid, and the outer space S2 contains atmosphere A as a second fluid, and the inner diameter side of the sliding components constituting the mechanical seal will be described as the sealed fluid space side (high pressure side) and the outer diameter side as the leakage space side (low pressure side). For ease of explanation, grooves and the like formed on the sliding surfaces may be marked with dots in the drawings.

[0018] 1 is an outside type mechanical seal that seals against a sealed fluid F that attempts to leak from the inner diameter side to the outer diameter side of the sliding surface, and has an outer space S2 that communicates with the atmosphere A. In this embodiment, the sealed fluid F is a high-pressure liquid, and the atmosphere A is a gas that is at a lower pressure than the sealed fluid F.

[0019] The mechanical seal is primarily composed of a stationary seal ring 10 as an annular sliding component and a rotary seal ring 20 as another annular sliding component. The rotary seal ring 20 is mounted on a rotary shaft 1 via a sleeve 2 so as to be rotatable together with the rotary shaft 1. The stationary seal ring 10 is mounted on a seal cover 5 fixed to a housing 4 of the device to which it is attached so as to be non-rotating but movable in the axial direction. The stationary seal ring 10 is biased in the axial direction by an elastic member 7, so that the sliding surface 11 of the stationary seal ring 10 and the sliding surface 21 of the rotary seal ring 20 slide closely against each other. The sliding surface 21 of the rotary seal ring 20 is flat, and this flat surface does not have any recesses such as grooves.

[0020] The stationary seal ring 10 and the rotating seal ring 20 are typically formed from a combination of SiC (hard material) or SiC (hard material) and carbon (soft material), but are not limited to this; any sliding material used as a sliding material for mechanical seals can be used. Examples of SiC include sintered bodies using boron, aluminum, carbon, or other sintering aids, as well as materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC consisting of SiC and Si, SiC-TiC, and SiC-TiN. Examples of carbon include a mixture of carbonaceous and graphitic materials, resin-molded carbon, and sintered carbon. In addition to the above sliding materials, metal materials, resin materials, surface-modified materials (coating materials), composite materials, and the like can also be used.

[0021] As shown in FIGS. 2 and 3, the rotary seal ring 20, which is the mating seal ring, slides counterclockwise relative to the stationary seal ring 10 as indicated by the solid arrow.

[0022] The sliding surface 11 of the stationary seal ring 10 is provided with dynamic pressure grooves 13 as dynamic pressure generating grooves, pumping grooves 14 , and an annular groove 15 .

[0023] The dynamic pressure grooves 13 are arranged evenly in the circumferential direction on the inner diameter side of the sliding surface 11 (for example, 32 grooves in this embodiment).

[0024] The dynamic pressure groove 13 extends linearly from an inner diameter end 13a on the inner space S1 side to an outer diameter end 13b on the outer space S2 side, inclined toward the downstream side in the rotation direction of the rotary seal ring 20, i.e., toward the downstream side in the relative rotation direction. The inner diameter end 13a of the dynamic pressure groove 13 communicates with the inner space S1, and the outer diameter end 13b, which serves as a dynamic pressure generating portion, is closed. Note that the dynamic pressure groove 13 is not limited to being linear when viewed in the axial direction, but may be arc-shaped or spiral-shaped, or may be a dimple surrounded by a land.

[0025] An annular groove 15 is provided on the outer diameter side of the dynamic pressure groove 13. This annular groove 15 is provided concentrically with the stationary seal ring 10. The area of ​​the sliding surface 11 other than the dynamic pressure groove 13, the pumping groove 14, and the annular groove 15 forms a flat land 12.

[0026] Furthermore, the annular groove 15 in this embodiment is formed to the same depth as the dynamic pressure grooves 13 and the pumping grooves 14. However, the annular groove 15 may have a different depth from the dynamic pressure grooves 13 and the pumping grooves 14. If the annular groove 15 is shallow, a relative negative pressure is easily generated, which makes it easier to recover the sealed fluid. If the annular groove 15 is deep, the sealed fluid can be more reliably supplied to the pumping grooves 14 than in the case of a shallower annular groove, resulting in superior pumping efficiency. In this way, the depth of the annular groove 15 can be selected appropriately depending on the conditions of use.

[0027] On the inner diameter side of the annular groove 15, pumping grooves 14 are arranged evenly in the circumferential direction (for example, four in this embodiment).

[0028] The pumping groove 14 extends linearly from an outer diameter end 14a on the outer space S2 side toward an inner diameter end 14b on the inner space S1 side, tilting in the circumferential direction toward the downstream side in the rotational direction of the rotary seal ring 20, i.e., toward the downstream side of relative rotation. The outer diameter end 14a of the pumping groove 14 communicates with the annular groove 15, and the inner diameter end 14b, which is the end located radially opposite the annular groove 15, is closed. Note that the pumping groove 14 is not limited to being linear when viewed in the axial direction, but may be arc-shaped, or generally J- or L-shaped when viewed in the axial direction. Note that the radial direction in the present invention may include at least a radial component, and the circumferential direction in the present invention may include at least a circumferential component.

[0029] The inner diameter ends 14b of the pumping grooves 14 are positioned radially inward relative to the outer diameter ends 13b of the dynamic pressure grooves 13. In other words, the pumping grooves 14 and the dynamic pressure grooves 13 are formed in positions where they overlap when viewed from the circumferential direction. In this way, when they are positioned so that they overlap when viewed from the circumferential direction, this is referred to as "overlapping in the circumferential direction" in the present invention. Similarly, when they are positioned so that they overlap when viewed from the radial direction, this is referred to as "overlapping in the radial direction" in the present invention.

[0030] Next, the action of the dynamic pressure grooves 13 and the pumping grooves 14 during relative rotation between the stationary seal ring 10 and the rotating seal ring 20 will be briefly described.

[0031] As shown in FIG. 3, when the rotary seal ring 20 rotates relative to the stationary seal ring 10, the fluid in the dynamic pressure grooves 13, pumping grooves 14, and annular groove 15 moves in accordance with the relative rotation of the rotary seal ring 20.

[0032] Specifically, in the dynamic pressure grooves 13, the sealed fluid F moves from the inner diameter end 13a to the outer diameter end 13b as shown by the black arrow in Fig. 3. This generates positive pressure at the outer diameter end 13b and its vicinity. In addition, the sealed fluid F is constantly supplied to the dynamic pressure grooves 13 from the internal space S1 through the inner diameter end 13a.

[0033] A part of the sealed fluid F discharged from the outer diameter end 13 b and its vicinity between the sliding surfaces 11 and 21 flows into the pumping groove 14 or the annular groove 15 .

[0034] 3, the fluid moves from the outer diameter end 14a to the inner diameter end 14b of the pumping groove 14 and is discharged from the inner diameter end 14b to between the sliding surfaces 11 and 21. This generates a slight positive pressure at and near the inner diameter end 14b of the pumping groove 14.

[0035] Furthermore, a relative negative pressure is generated in the vicinity of the outer diameter end 14a of the pumping groove 14 and in the annular groove 15. As a result, the sealed fluid F discharged between the sliding surfaces 11 and 21 is easily recovered in the pumping groove 14 and the annular groove 15.

[0036] Furthermore, most of the fluid discharged from the inner diameter end 14b of the pumping groove 14 to between the sliding surfaces 11, 21 flows into the adjacent dynamic pressure groove 13 on the downstream side in the circumferential direction.

[0037] As described above, the pumping groove 14 is provided on the inner diameter side of the annular groove 15, i.e., on the inner space S1 side, and when the sliding surfaces 11 and 21 rotate relative to each other, the pumping groove 14 causes the fluid to flow from the annular groove 15 to the inner space S1 side, creating a relatively negative pressure in the annular groove 15. As a result, the fluid that has flowed out between the sliding surfaces 11 and 21 can be recovered over the entire circumference by the annular groove 15, and leakage of the sealed fluid F into the outer space S2 side can be suppressed, thereby improving the sealing performance.

[0038] Furthermore, since the pumping groove 14 is connected to the annular groove 15, the fluid flows smoothly from the annular groove 15 to the pumping groove 14, and a relative negative pressure is likely to occur in the annular groove 15.

[0039] In addition, a plurality of pumping grooves 14 are equally spaced in the circumferential direction, which allows the fluid to be discharged between the sliding surfaces 11 and 21 from a plurality of locations in the circumferential direction of the annular groove 15, thereby generating a negative pressure in a well-balanced manner.

[0040] Furthermore, since a positive pressure can be generated at the inner diameter ends 14b of the pumping grooves 14 that are evenly spaced in the circumferential direction, the floating balance between the stationary seal ring 10 and the rotary seal ring 20 can be improved.

[0041] Furthermore, since the annular groove 15 is a ring, pressure is less likely to become uneven in the circumferential direction of the annular groove 15, and negative pressure can be generated in a well-balanced manner in the circumferential direction.

[0042] Furthermore, the hydrodynamic grooves 13 are provided on the inner space S1 side of the annular groove 15, and positive pressure can be generated at multiple locations in the circumferential direction by the pumping grooves 14 and the hydrodynamic grooves 13. This improves the balance of floating between the stationary seal ring 10 and the rotating seal ring 20, thereby improving lubrication.

[0043] Furthermore, since the inner diameter end 14b of the pumping groove 14 is located radially inward of the outer diameter end 13b of the dynamic pressure groove 13, there is little interference between the positive pressure generated at the inner diameter end 14b of the pumping groove 14 and the positive pressure generated at the outer diameter end 13b of the dynamic pressure groove 13. Furthermore, the pumping groove 14 and the dynamic pressure groove 13 can generate positive pressure in a balanced manner in the radial direction of the sliding surfaces 11, 21. Furthermore, since the pumping groove 14 extends radially toward the sealed fluid space, i.e., toward the inner space S1, the fluid is pushed out toward the sealed fluid side, thereby reducing leakage.

[0044] Furthermore, since the inner diameter end 14b of the pumping groove 14 is positioned circumferentially to the side of the dynamic pressure groove 13, more specifically, upstream of the relative rotation, the fluid that flows out from the inner diameter end 14b of the pumping groove 14 between the sliding surfaces 11, 21 can be easily recovered by the dynamic pressure groove 13.

[0045] Furthermore, since the outer diameter end 13b of the dynamic pressure groove 13 is positioned circumferentially to the side of the pumping groove 14, more specifically, upstream of the relative rotation, that is, since the pumping groove 14 and the dynamic pressure groove 13 overlap in the circumferential direction, the fluid that flows out from the outer diameter end 13b of the dynamic pressure groove 13 to between the sliding surfaces 11, 21 can be easily recovered by the pumping groove 14.

[0046] Furthermore, since the pumping groove 14 and the dynamic pressure groove 13 overlap in the circumferential direction, the outer diameter end 13b of the dynamic pressure groove 13 can be positioned close to the annular groove 15, so that fluid can be supplied from the dynamic pressure groove 13 to the annular groove 15, and excessive poor lubrication of the annular groove 15 can be prevented.

[0047] Furthermore, since the dynamic pressure grooves 13 communicate with the inner space S1, the sealed fluid F in the dynamic pressure grooves 13 is not depleted, and the dynamic pressure generating effect is high.

[0048] Furthermore, since the dynamic pressure grooves 13 are not connected to the annular groove 15, they are not affected by fluctuations in pressure within the annular groove 15 and can generate a stable positive pressure.

[0049] Furthermore, the fluid present between the sliding surfaces 11, 21 may contain contaminants, and if contaminants exist between the lands, there is a risk of abnormal noise, damage, etc. In this embodiment, the contaminants can be discharged to the annular groove 15 by the fluid discharged from the dynamic pressure grooves 13, and the contaminants can be discharged to the dynamic pressure grooves 13 located downstream of the relative rotation by the fluid discharged from the pumping grooves 14. Therefore, it is possible to prevent contaminants from remaining between the lands.

[0050] Furthermore, since a plurality of dynamic pressure grooves 13 are provided between the two pumping grooves 14, contaminants between the lands can be discharged to the annular groove 15 over a wide area.

[0051] Furthermore, by ensuring a large circumferential width between the pumping groove 14 and the dynamic pressure groove 13 arranged downstream in the relative rotation, the dynamic pressure generated in the pumping groove 14 is less likely to interfere with the dynamic pressure groove 13 arranged downstream in the relative rotation, thereby improving sealing performance. Furthermore, by ensuring a large circumferential width between the pumping groove 14 and the dynamic pressure groove 13 arranged upstream in the relative rotation, the dynamic pressure generated in the dynamic pressure groove 13 is less likely to interfere with the pumping groove 14, thereby improving the floating effect between the sliding surfaces.

[0052] In this embodiment, the annular groove 15 has a rectangular cross section, but the cross section may be U-shaped, semicircular, triangular, or may be modified as appropriate. The same applies to the dynamic pressure groove 13 and the pumping groove 14.

[0053] Furthermore, in this embodiment, the annular groove 15 is shown as having a circular ring shape, but it may have a wave shape when viewed in the axial direction, or a star-shaped polygonal shape, etc., as long as it is endless.

[0054] Furthermore, in this embodiment, a configuration in which a plurality of pumping grooves 14 are provided in the circumferential direction has been exemplified, but it is sufficient that at least one pumping groove is provided.

[0055] Next, a sliding element according to a second embodiment will be described with reference to Fig. 4. Note that the description of the same configuration as in the first embodiment will be omitted.

[0056] 4, in the stationary seal ring 410 of the second embodiment, the outer diameter end 414a of the pumping groove 414 is disposed close to the annular groove 415 and is not in communication with the annular groove 415. For example, it is sufficient that the distance between the outer diameter end 414a and the annular groove 415 is equal to or less than the groove width of the annular groove 415.

[0057] When the stationary seal ring 410 and the rotary seal ring 20 rotate relative to each other, the fluid in the annular groove 415 is sucked in by the negative pressure generated near the outer diameter end 414a of the pumping groove 414, generating a relative negative pressure in the annular groove 415. In addition, since the negative pressure is generated near the outer diameter end 414a, the sealed fluid between the sliding surfaces is easily sucked in directly from the vicinity of the outer diameter end 414a.

[0058] Next, a sliding element according to a third embodiment will be described with reference to Fig. 5. Note that the description of the same configuration as in the first embodiment will be omitted.

[0059] As shown in FIG. 5, the pumping groove 514 in the stationary seal ring 510 of the third embodiment is composed of a first groove portion 514A and a second groove portion 514B.

[0060] The first groove 514A extends radially inward from the annular groove 515 while tilting downstream in the direction of relative rotation. The second groove 514B extends radially inward from the inner end of the first groove 514A while tilting upstream in the direction of relative rotation. That is, an acutely bent corner 514C is formed between the first groove 514A and the second groove 514B.

[0061] Furthermore, the dynamic pressure grooves 513 are arranged between the pumping grooves 514 that are adjacent to each other in the circumferential direction.

[0062] When the stationary seal ring 510 and the rotary seal ring 20 rotate relative to each other, fluid flows from the annular groove 515 to the first groove portion 514A. The fluid in the first groove portion 514A flows from its outer diameter end 514a toward the corner 514C. The fluid in the second groove portion 514B flows from its inner diameter end 514b toward the corner 514C. As a result, positive pressure is generated at and near the corner 514C.

[0063] Furthermore, the fluid that flows out from the outer diameter end 513b of the dynamic pressure groove 513 between the sliding surfaces is recovered at the inner diameter end 514b of the second groove portion 514B located downstream of the outer diameter end 513b in the relative rotation direction, so that positive pressure can be efficiently generated at the corner portion 514C and its vicinity by using the high-pressure sealed fluid F that flows out from the dynamic pressure groove 513 between the sliding surfaces.

[0064] Next, a sliding element according to a fourth embodiment will be described with reference to Fig. 6. Note that the description of the same configuration as in the first embodiment will be omitted.

[0065] As shown in FIG. 6, the stationary seal ring 810 of the fourth embodiment has dynamic pressure grooves 813A, 813B, and 813C of different lengths provided between two pumping grooves 814.

[0066] The dynamic pressure groove 813A arranged most upstream in the relative rotation direction is shorter than the dynamic pressure groove 813B adjacent thereto on the downstream side in the relative rotation direction, and the dynamic pressure groove 813B is shorter than the dynamic pressure groove 813C adjacent thereto on the downstream side in the relative rotation direction.

[0067] Some of the contaminants present in the land near the outer diameter end 813Ab of the dynamic pressure groove 813A are pushed out to the vicinity of the outer diameter end 813Bb of the dynamic pressure groove 813B. Some of the contaminants present in the land near the outer diameter end 813Bb of the dynamic pressure groove 813B are pushed out to the vicinity of the outer diameter end 813Cb of the dynamic pressure groove 813C. Contaminants present in the land near the outer diameter end 813Cb of the dynamic pressure groove 813C are pushed out into the annular groove 815. In other words, contaminants can be discharged into the annular groove 815 over a wide radial range.

[0068] Additionally, the outer diameter ends 813Ab, 813Bb, and 813Cb are farthest from the annular groove 815 in ascending order of proximity to the upstream pumping groove 814. The fluid flows from the upstream pumping groove 814 toward the downstream side. As a result, the fluid pushed out from the outer diameter ends 813Ab, 813Bb, and 813Cb and the upstream pumping groove 814 toward the annular groove 815 is uniform in the circumferential direction.

[0069] Although the dynamic pressure grooves 813A, 813B, and 813C are illustrated as becoming longer toward the downstream side in the relative rotation direction, the length of each dynamic pressure groove may be freely changed.

[0070] Next, a sliding element according to a fifth embodiment will be described with reference to Fig. 7. Note that the description of the same configuration as in the first embodiment will be omitted.

[0071] 7, the stationary seal ring 910 of this fifth embodiment has pumping grooves 914 and dynamic pressure grooves 913 arranged alternately in the circumferential direction. This allows the positive pressure generated in the pumping grooves 914 and the positive pressure generated in the dynamic pressure grooves 913 to act in a well-balanced manner in the circumferential direction.

[0072] Next, a sliding element according to a sixth embodiment will be described with reference to Fig. 8. Note that the description of the same configuration as in the first embodiment will be omitted.

[0073] The mechanical seal to which the stationary seal ring 710 of this embodiment 6 is applied seals the sealed fluid F present on the outer space S12 side of the sliding surfaces 711, 21, and is an inside type in which the inner space S11 is connected to the atmosphere A.

[0074] The sliding surface 711 is formed with a plurality of pumping grooves 714 , a plurality of dynamic pressure grooves 713 , and an annular groove 715 .

[0075] The pumping groove 714 and the dynamic pressure groove 713 have shapes that are approximately inverted in the radial direction from the pumping groove 14 and the dynamic pressure groove 13 in Example 1. That is, the pumping groove 714 is provided on the outer diameter side of the annular groove 715, and the dynamic pressure groove 713 communicates with the outer space S12.

[0076] As a result, as shown by the solid arrows, rotation of the rotary seal ring 20 causes fluid to flow from the annular groove 715 toward the pumping groove 714, generating a relative negative pressure in the annular groove 715. Also, positive pressure is generated at and near the outer diameter end 714a of the pumping groove 714. Also, positive pressure is generated at and near the inner diameter end 713a of the dynamic pressure groove 713.

[0077] In this way, the sliding component of the present invention may be applied to an environment in which the sealed fluid space is on the outer diameter side of the sliding surface and the leakage space is on the inner diameter side of the sliding surface.

[0078] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0079] For example, in the above-described Examples 1 to 6, the sliding parts are provided with dynamic pressure generating grooves, but it is sufficient that the sliding parts are provided with an annular groove and a pumping groove, and the dynamic pressure generating groove may be omitted.

[0080] Furthermore, in the first to sixth embodiments, a mechanical seal for an automobile is used as an example of the sliding part, but other mechanical seals for general industrial machinery, etc. may also be used. Furthermore, the sliding part is not limited to a mechanical seal, and may be a sliding bearing or other sliding part other than a mechanical seal.

[0081] In addition, in the above-described first to sixth embodiments, the sealed fluid is described as a high-pressure liquid, but it is not limited to this and may be a gas or a low-pressure liquid, or a mist-like mixture of liquid and gas.

[0082] Furthermore, in the above-described Examples 1 to 6, the fluid on the leakage space side was described as being atmospheric air, which is a low-pressure gas, but this is not limited to this and it may be a liquid or a high-pressure gas, or a mist-like mixture of liquid and gas.

[0083] In addition, in the above-described first to sixth embodiments, the sealed fluid space side has been described as the high-pressure side and the leakage space side as the low-pressure side, but the sealed fluid space side may be the low-pressure side and the leakage space side may be the high-pressure side, or the sealed fluid space side and the leakage space side may be at approximately the same pressure.

[0084] Furthermore, in the first to sixth embodiments, examples have been described in which the dynamic pressure generating grooves and pumping grooves are provided in the stationary seal ring, but the dynamic pressure generating grooves and pumping grooves may also be provided in the rotary seal ring.

[0085] In addition, in the above-described Examples 1 to 6, the dynamic pressure generating groove and the pumping groove are provided in the same sliding component, but the dynamic pressure generating groove and the pumping groove may be provided in separate sliding components, or the dynamic pressure generating groove and the pumping groove may be provided in both sliding components.

[0086] REFERENCE SIGNS LIST 10 Stationary seal ring (sliding component) 11 Sliding surface 13 Dynamic pressure groove (dynamic pressure generating groove) 13b Outer diameter end (dynamic pressure generating portion) 14 Pumping groove (pumping groove) 14b Inner diameter end (end portion) 15 Annular groove 20 Rotary seal ring (sliding component) 21 Sliding surface A Atmosphere (pumping groove) F Sealed fluid S1 Inner space (pumping groove) S2 Outer space (leakage space)

Claims

1. A sliding component in which a pair of sliding surfaces rotate relative to each other and partition between a fluid space to be sealed and a leakage space, wherein at least one of the sliding surfaces includes a hydrodynamic groove and an endless annular groove that is located on the leakage space side of the hydrodynamic groove and extends in the circumferential direction, and one of the sliding surfaces or the other sliding surface includes a pumping groove provided on the fluid space to be sealed side of the annular groove, and an end portion of the pumping groove that is located on the opposite side in the radial direction from the annular groove and the hydrodynamic groove overlap in the circumferential direction.

2. The sliding component according to claim 1, wherein the hydrodynamic groove communicates with the fluid space to be sealed.

3. The sliding component according to claim 1, wherein the pumping groove communicates with the annular groove.

4. The sliding component according to claim 1, wherein a plurality of the pumping grooves are arranged in the circumferential direction.

5. The sliding component according to claim 1, wherein the annular groove is an annulus.

6. The sliding component according to claim 1, wherein the pumping groove extends radially toward the fluid space to be sealed side.

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