sliding member

Abstract

The present application provides a sliding member capable of obtaining high lubricity over the entire surface of a sliding surface. A ring-shaped sliding member 10 is arranged at a portion that relatively rotates in a rotary machine, a plurality of positive pressure generating grooves 15 are arranged in parallel along a circumferential direction on a sliding surface 11 of the sliding member 10, a positive pressure is generated in each of the positive pressure generating grooves 15 by introducing a sealed fluid F from a side of the sealed fluid when the sliding member 10, 20 relatively rotates, a leading end portion 9a is provided at a leading end of each of the positive pressure generating grooves 15 on a downstream side in a relatively rotating direction, and at least a portion of the leading end portions 9a arranged in parallel in the circumferential direction is arranged at different positions in a radial direction.

Description

[0001] This application is a divisional application of the invention patent application with the application date of 2020-04-07, the application number of 202080026547.2, and the name of “Sliding member”. TECHNICAL FIELD

[0002] The present application relates to a sliding member for relative rotation, for example, a sliding member used for a shaft seal device for a rotating shaft of a rotating machine such as an automobile, a general industrial machine, or other sealing field, or a bearing of a machine such as an automobile, a general industrial machine, or other bearing field. BACKGROUND

[0003] As a shaft seal device for preventing leakage of a sealed liquid, for example, a mechanical seal has a pair of annular sliding members that relatively rotate and whose sliding surfaces slide against each other. In such a mechanical seal, in recent years, in order to protect the environment and the like, it is desired to reduce energy lost due to sliding, and some provide a positive pressure generating groove that communicates with the high-pressure sealed liquid side and is blocked at one end of the sliding surface of the sliding member.

[0004] For example, the mechanical seal shown in Patent Document 1 has a plurality of positive pressure generating grooves arranged in the circumferential direction on the sliding surface of one sliding member, which are arranged so as to extend obliquely toward the downstream side in the rotation direction with one side facing the atmosphere side and have an opening portion that communicates with the sealed fluid side. Thus, when the sliding members relatively rotate, the positive pressure generating grooves are introduced with the sealed liquid, the sealed liquid is concentrated at the leading end portion located at the most downstream end of the positive pressure generating grooves to generate positive pressure, a liquid film is generated between the sliding surfaces and the sliding surfaces slightly separate from each other, thereby improving lubricity and achieving low friction.

[0005] In addition, in the mechanical seal shown in Patent Document 2, a plurality of V-shaped grooves that are V-shaped with the tip portion facing the downstream side in the rotation direction are arranged in the circumferential direction on the sliding surface of one sliding member. One side of the two sides of the V-shaped groove that communicates with the sealed liquid side functions as a positive pressure generating groove, and in addition, the tip portion where the two sides of the V-shaped groove intersect is located at the leading end portion on the downstream side in the relative rotation direction. Thus, as in Patent Document 1, the sealed liquid is concentrated at the tip portion of the V-shaped groove, thereby forming a liquid film of the sealed liquid to improve lubricity.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT DOCUMENTS

[0008] Patent Document 1: Japanese Patent Application Publication No. 5-164249 (page 4, Figure 2 , 3 ).

[0009] Patent Document 2: U.S. Patent No. 6,152,452 (page 14,Figure 8 ).

[0010] However, in Patent Literature 1, the frontmost end portions of the plurality of positive pressure generating grooves arranged along the circumferential direction of the sliding surface are located at the same position in the radial direction, that is, all of the plurality of frontmost end portions are juxtaposed on the same circumference. Similarly, in Patent Literature 2, the tips of the plurality of V-shaped grooves arranged along the circumferential direction of the sliding surface are all juxtaposed on the same circumference. Therefore, in Patent Literatures 1 and 2, the positive pressure is generated with the frontmost end portions or the tips juxtaposed on the same circumference as the center, and thus the radial pressure gradient of the sliding surface becomes large, and it is difficult to form a uniform liquid film over a large area of the sliding surface, and as a result, high lubricity is not obtained over the entire surface of the sliding surface, and there is a risk that the sliding surface is in a state of insufficient lubrication. Further, in Patent Literature 2, the liquid film of the sealed liquid is formed with the tips juxtaposed on the same circumference as the center, and thus the problem is that the gas-liquid interface between the sealed liquid side of the sealed liquid and the leakage side atmosphere is fixed to a specific narrow range in the radial direction when the sliding members relatively rotate. SUMMARY

[0011] The present application has been made in view of such problems, and an object thereof is to provide a sliding member capable of obtaining high lubricity over the entire surface of a sliding surface.

[0012] To solve the problem, the sliding member of the present application is a ring-shaped sliding member arranged at a position where members relatively rotate in a rotary machine,

[0013] A plurality of positive pressure generating grooves are juxtaposed in the circumferential direction on the sliding surface of the sliding member, the positive pressure generating grooves generate positive pressure by being introduced into a sealed fluid on the sealed fluid side when the sliding member relatively rotates, each of the positive pressure generating grooves has a frontmost end portion at the frontmost end on the downstream side in the relative rotation direction, and at least a part of the plurality of frontmost end portions juxtaposed in the circumferential direction is arranged at different positions in the radial direction.

[0014] Thus, when the sliding member relatively rotates, the sealed fluid flows to the downstream side in the relative rotation direction of each of the positive pressure generating grooves, and concentrates on the frontmost end portion to generate positive pressure. At least a part of the frontmost end portion of each of the positive pressure generating grooves is arranged at different positions in the radial direction, and thus positive pressure is generated at different positions in the radial direction in the circumferential direction on the sliding surface, and the pressure gradient in the radial direction of the sliding surface becomes small, and it is easy to form a liquid film uniformly over a large area of the sliding surface. Therefore, the lubricity of the sliding surface by the sealed fluid is good.

[0015] It can also be that the plurality of frontmost end portions juxtaposed in the circumferential direction are regularly arranged in the circumferential direction.

[0016] Thus, when the sliding member relatively rotates, a fluid film of the sealed fluid is formed at the regularly arranged positions, and thus the lubricity is good. Thus, when the sliding member relatively rotates, a fluid film of the sealed fluid is formed at the regularly arranged positions, and thus the lubricity is good.

[0017] Also, the plurality of the frontmost end portions arranged side by side can be configured in a wave shape along the circumferential direction with the radial positions gradually changing.

[0018] Thus, the fluid film of the sealed fluid is formed in a wave shape by the sealed fluid when the sliding member is relatively rotated, and lubrication is good.

[0019] Also, the positive pressure generation groove can have an opening portion that communicates with the sealed fluid side.

[0020] Thus, the sealed fluid is easily introduced from the sealed fluid side into the opening portion of the positive pressure generation groove when the sliding member is relatively rotated, and thus the fluid film of the sealed fluid is easily formed at the frontmost end portion, and lubrication of the sliding surface is good.

[0021] Also, the positive pressure generation groove can be arranged extending obliquely toward the downstream side in the relative rotation direction while facing the leakage side,

[0022] The negative pressure generation groove can be arranged extending obliquely toward the upstream side in the relative rotation direction while continuously facing the leakage side from the leakage side end portion of the positive pressure generation groove.

[0023] Thus, the fluid film of the sealed fluid formed at the frontmost end portion is sucked into the negative pressure generation groove that is a relative negative pressure when the sliding member is relatively rotated, and leakage of the sealed fluid to the leakage side can be prevented, and the sealing performance of the sliding member can be improved.

[0024] Also, a land portion extending in the circumferential direction can be arranged on the leakage side of the negative pressure generation groove of the sliding surface.

[0025] Thus, the leakage side end portion of the negative pressure generation groove is blocked by the land portion, and thus leakage of the sealed fluid to the leakage side can be prevented when the sliding member is at rest.

[0026] Also, the land portion from the negative pressure generation groove to the leakage side can have a fixed radial width in the circumferential direction.

[0027] Thus, the radial position of the leakage side end portion of the negative pressure generation groove is fixed in the circumferential direction, and thus manufacturing is easy.

[0028] Also, the plurality of the frontmost end portions arranged side by side and the bent portions on the upstream side in the relative rotation direction at which the positive pressure generation groove and the negative pressure generation groove intersect can be configured in a wave shape along the circumferential direction with the radial positions gradually changing.

[0029] Thus, the frontmost end portions and the bent portions are arranged on a virtual curve in a wave shape, and thus manufacturing is easy.

[0030] Also, a second positive pressure generating groove can be provided on the sliding surface, the second positive pressure generating groove being independent of the positive pressure generating groove on the leakage side, the fluid introduced on the leakage side of the positive pressure generating groove generating positive pressure when the rotating machine relatively rotates, and the second front end portion being provided at the front end on the downstream side in the direction of relative rotation of the second positive pressure generating groove.

[0031] Thus, the leakage side fluid flows to the downstream side in the direction of relative rotation of the second positive pressure generating groove when the sliding member relatively rotates, and concentrates in the second front end portion to generate positive pressure, so the sealed fluid approaching the vicinity of the second front end portion from the sealed fluid side can be bounced back, and the leakage of the sealed fluid to the leakage side can be prevented.

[0032] Also, the second positive pressure generating groove can be provided corresponding to the number and position of the positive pressure generating groove.

[0033] Thus, the second positive pressure generating groove can be machined in accordance with the number and position of the positive pressure generating groove, and manufacturing can be facilitated.

[0034] Also, a land portion extending in the circumferential direction can be provided between the radial directions of the positive pressure generating groove and the second positive pressure generating groove.

[0035] Thus, the positive pressure generating groove and the second positive pressure generating groove can be separated, and the functions of both can be clearly defined when relatively rotating.

[0036] Also, the radial width of the land portion provided between the radial directions of the positive pressure generating groove and the second positive pressure generating groove can be fixed in the circumferential direction.

[0037] Thus, the second front end portion is separated from the front end portion by a fixed size on the leakage side, and the second front end portion generating positive pressure when relatively rotating is provided at a position of a different diameter length in the circumferential direction, so the sealed fluid flowing from the fluid film generated at the front end portion can be prevented from entering the leakage side when relatively rotating.

[0038] Also, the front end portion and the corner portion on the upstream side in the direction of relative rotation of the leakage side end portion of the positive pressure generating groove, which are provided in plurality, can be gradually changed in the radial direction along the circumferential direction, and can be provided in a wave shape.

[0039] Thus, the front end portion and the corner portion can be provided on a virtual curve in a wave shape, and manufacturing can be facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a longitudinal sectional view showing an example of a mechanical seal in Embodiment 1 of the present application.

[0041] Figure 2 is a view of the sliding surface of the stationary seal ring as viewed from the axial direction.

[0042] Figure 3 is a detail enlargement of a sliding surface of the stationary seal ring in relative rotation.

[0043] Figure 4 is a view of a sliding surface of the stationary seal ring in Example 2 of the present application, as viewed from the axial direction.

[0044] Figure 5 is a detail enlargement of a sliding surface of the stationary seal ring in relative rotation.

[0045] Figure 6 is an explanatory view showing Modified Example 1 of the present application.

[0046] Figure 7 is an explanatory view showing Modified Example 2 of the present application.

[0047] Figure 8 is a view of a sliding surface of the stationary seal ring in Example 3 of the present application, as viewed from the axial direction.

[0048] Figure 9 is a detail enlargement of a sliding surface of the stationary seal ring in relative rotation.

[0049] Figure 10 is a detail enlargement of a sliding surface of the stationary seal ring in relative rotation, when the sliding surface is entered by the sealing liquid into the second positive pressure generating groove.

[0050] Figure 11 is an explanatory view showing Modified Example 3 of the present application. DETAILED DESCRIPTION

[0051] Based on the Examples, the following describes a method for implementing the sliding member to which the present application pertains.

[0052] Example 1

[0053] The sliding member pertaining to Example 1 is described with reference to Figures 1 to 3 . In this example, the sliding member is described as an example of a mechanical seal. The outer diameter side of the sliding member constituting the mechanical seal is described as the sealed liquid side (high pressure side), and the inner diameter side is described as the atmospheric side (leakage side, low pressure side). However, the present application is not limited to this, and the sealed liquid side can be the low pressure side, and the leakage side can be the high pressure side. Further, the sealed fluid is not limited to a liquid, and can be a gas, such as air. In the drawings, the grooves and the like formed on the sliding surface are sometimes indicated by points for ease of explanation.

[0054] Figure 1The mechanical seal shown is a typical industrial machinery seal, an inside-type mechanical seal, designed to seal against leakage of the sealed liquid F from the sliding surface towards the atmosphere. It primarily consists of a rotating sealing ring 20 and a stationary sealing ring 10. The rotating sealing ring 20 is a ring-shaped sliding component, configured to rotate with the rotating shaft 1 via a sleeve 2. The stationary sealing ring 10, also a ring-shaped sliding component, is mounted on a sealing cover 5 fixed to the housing 4 of the installed equipment in a non-rotating state, but is axially movable. Force is applied radially to the stationary sealing ring 10 via a bellows 7, causing the sliding surface 11 of the stationary sealing ring 10 and the sliding surface 21 of the rotating sealing ring 20 to slide in close contact. Furthermore, the sliding surface 21 of the rotating sealing ring 20 can be a flat surface or have a recessed portion.

[0055] The stationary sealing ring 10 and the rotary sealing ring 20 are typically formed from SiC (hard material) together or from a combination of SiC (hard material) and carbon (soft material), but are not limited to this. Any sliding material that can be used as a sliding material for mechanical seals is acceptable. Among these, SiC is represented by sintered bodies with boron, aluminum, carbon, etc., as sintering aids. Materials composed of two or more phases with different compositions and components exist, such as SiC with dispersed graphite particles, reaction-sintered SiC composed of SiC and Si, SiC-TiC, SiC-TiN, etc. Carbon is represented by carbon formed from a mixture of carbon and graphite, and can be formed using resin molding carbon, sintered carbon, etc. In addition to the above-mentioned sliding materials, metallic materials, resin materials, surface-modified materials (coating materials), or composite materials can also be used.

[0056] like Figure 2 As shown, the rotating sealing ring 20 slides relative to the stationary sealing ring 10 as indicated by the arrow. On the sliding surface 11 of the stationary sealing ring 10, a plurality of dynamic pressure generating mechanisms 14 are evenly arranged along the circumferential direction of the stationary sealing ring 10. The portion of the sliding surface 11 other than the dynamic pressure generating mechanisms 14 forms a flat-end facet 12.

[0057] Below is a summary of the dynamic pressure generating mechanism 14, based on... Figure 2 , Figure 3 This will be explained below. Furthermore, when the stationary sealing ring 10 and the rotating sealing ring 20 rotate relative to each other, Figure 3 The left side of the paper serves as the downstream side of the sealed liquid F, and... Figure 3 The right side of the paper is used as the upstream side of the sealed liquid F for explanation.

[0058] The dynamic pressure generating mechanism 14 has a positive pressure generating groove 15, which has an opening 15a that opens to and communicates with the sealed liquid side. The opening is inclined downstream towards the atmosphere side and is linearly recessed to the atmosphere side end 9b, which is blocked as a leakage side end. A foremost end 9a is located at the foremost point downstream of this atmosphere side end 9b. A ground portion 12 is provided on the atmosphere side of the positive pressure generating groove 15, thus preventing leakage of the sealed liquid F to the atmosphere side when the rotating sealing ring 20 is stationary. Furthermore, the foremost ends 9a of the plurality of positive pressure generating grooves 15 arranged side-by-side gradually change their radial position along the circumferential direction, and are arranged on a smooth and continuous virtual curve C that is shaped like a circumferential sine wave. Moreover, not limited to this embodiment, although not specifically illustrated, in addition to the foremost end 9a, the corner 9c located upstream of the atmosphere side end 9b of the positive pressure generating groove 15 may also be arranged on the virtual curve C. Furthermore, the virtual curve C is periodic, but it is not limited to this and may not be periodic.

[0059] Furthermore, the multiple positive pressure generating grooves 15 are configured such that each opening 15a is evenly arranged along the circumference and the inclination angle of each positive pressure generating groove 15 is different. Therefore, multiple positive pressure generating grooves 15 can be arranged side by side in a narrow area. However, it is not limited to this. It can also be configured such that each opening 15a is not evenly arranged along the circumference and the inclination angle of each positive pressure generating groove 15 is fixed.

[0060] Next, the operation when the stationary sealing ring 10 and the rotating sealing ring 20 rotate relative to each other will be explained. First, when the rotating sealing ring 20 is not rotating and the general industrial machinery is not in operation, the sealed liquid F, which is closer to the sealed liquid side than the sliding surfaces 11 and 21, slightly enters between the sliding surfaces 11 and 21 due to capillary action, and the dynamic pressure generating mechanism 14 is filled with the sealed liquid F flowing in from the opening 15a of the positive pressure generating groove 15. Furthermore, the sealed liquid F has a higher viscosity than gas, so the amount leaking from the dynamic pressure generating mechanism 14 to the atmospheric side when the general industrial machinery is stopped is extremely small.

[0061] Below, as Figure 3 As shown, when the rotating sealing ring 20 rotates relative to the stationary sealing ring 10, the sealed liquid F on the sealed liquid side flows from the opening 15a of the positive pressure generating tank 15 towards the foremost end 9a, as indicated by arrow H1, generating dynamic pressure within the positive pressure generating tank 15. Furthermore, inside the positive pressure generating tank 15, the positive pressure gradually increases from the upstream opening 15a towards the downstream foremost end 9a.

[0062] That is, the pressure is highest near the leading end portion 9a located at the most upstream side of the positive pressure generation grooves 15, the sliding surfaces 11, 21 are separated from each other, and the sealing liquid F flows out from near the leading end portion 9a to between the sliding surfaces 11, 21 on the periphery thereof as indicated by an arrow H2, whereby a liquid film of the sealing liquid F is formed on the sealing liquid side between the sliding surfaces 11, 21. Thus, the liquid film of the sealing liquid F is formed near the leading end portions 9a of the plurality of positive pressure generation grooves 15, and thus so-called fluid lubrication is achieved between the sliding surfaces 11, 21, the lubricity is improved, and low friction is achieved. Further, the sealing liquid F flows slightly to the downstream side from portions other than the leading end portions 9a of the positive pressure generation grooves 15.

[0063] Further, the plurality of leading end portions 9a are arranged on the virtual curve C of the sinusoidal shape as described above, and thus when the rotary seal ring 20 relatively rotates, the positive pressure is generated at different positions in the radial direction along the circumferential direction on the sliding surface 11, the radial pressure gradient in the sliding surface 11 is small, and thus the liquid film is easily formed substantially uniformly over a large area of the sliding surface 11. Thus, the lubricity by the sealing liquid F of the sliding surface 11 is good.

[0064] Further, the sealing liquid F flowing out from the positive pressure generation grooves 15 is introduced into other positive pressure generation grooves 15 arranged on the downstream side of the positive pressure generation grooves 15 as indicated by an arrow H3, and thus the pressure in the positive pressure generation grooves 15 can be stabilized.

[0065] As described above, at least a portion of the plurality of leading end portions 9a arranged in parallel in the circumferential direction are arranged at different positions in the radial direction, and thus when the rotary seal ring 20 relatively rotates, the sealing liquid F flows to the downstream side in the relative rotation direction of each positive pressure generation groove 15, and the positive pressure is generated by being concentrated on the leading end portion 9a. At least a portion of the leading end portions 9a of the respective positive pressure generation grooves 15 are arranged at different positions in the radial direction, and thus when the rotary seal ring 20 relatively rotates, the positive pressure is generated at different positions in the radial direction along the circumferential direction on the sliding surface 11, the radial pressure gradient in the sliding surface 11 is small, and thus the liquid film is easily formed substantially uniformly over a large area of the sliding surface 11. Thus, the lubricity by the sealing liquid F of the sliding surface 11 is good.

[0066] Further, the plurality of leading end portions 9a arranged in parallel are regularly arranged in the circumferential direction, and thus when the rotary seal ring 20 relatively rotates, the liquid film of the sealing liquid F is formed at the regularly arranged positions, and thus the lubricity is good.

[0067] Further, the plurality of leading end portions 9a arranged in parallel are regularly arranged in the circumferential direction, and thus when the rotary seal ring 20 relatively rotates, the liquid film of the sealing liquid F is formed at the regularly arranged positions, and thus the lubricity is good.

[0068] Further, the positive pressure generating groove 15 has an opening portion 15a that communicates with the sealed liquid side, and thus when the rotary seal ring 20 relatively rotates, the sealed liquid F is easily introduced from the sealed liquid side at the front end portion 9a of the positive pressure generating groove 15, and thus a liquid film of the sealed liquid F is easily formed at the front end portion 9a, and the lubricity of the sliding surface 11 is good.

[0069] Example 2

[0070] Next, the sliding member related to Example 2 will be described with reference to Figures 4 to 7 , and the description of the configuration that is repeated with the same configuration as Example 1 will be omitted.

[0071] As shown in Figure 4 and Figure 5 , the V-shaped dynamic pressure generating mechanism 141, in which the tip portion faces the downstream direction, is provided at the sliding surface 11 of the stationary seal ring 101. The V-shaped dynamic pressure generating mechanism 141 has a positive pressure generating groove 15 in which one side that is open to the sealed liquid side and one side that is inclined to the atmospheric side in a straight line is recessed, and a negative pressure generating groove 171 in which the other side that is open to the atmospheric side and one side that is inclined to the upstream side is recessed in a straight line to the atmospheric side end portion 171a that is blocked as a leakage side end portion. The tip portion where the two sides of the V shape intersect corresponds to the front end portion 9a. Further, the radial positions of the respective front end portions 9a of the positive pressure generating grooves 15 that are provided in parallel gradually change along the circumferential direction, and are arranged on a virtual curve C that is a smooth and continuous sinusoidal wave shape in the circumferential direction.

[0072] Next, the operation when the rotary seal ring 20 relatively rotates will be described. First, when the general industrial machine in which the rotary seal ring 20 does not rotate is not operating, the sealed liquid F on the sealed liquid side of the sliding surface 11, 21 slightly enters between the sliding surfaces 11, 21 due to the capillary phenomenon, and the dynamic pressure generating mechanism 141 is filled with the sealed liquid F that flows from the opening portion 15a of the positive pressure generating groove 15. Further, the viscosity of the sealed liquid F is high compared to that of the gas, and thus the amount of leakage to the atmospheric side from the dynamic pressure generating mechanism 141 when the general industrial machine is stopped is extremely small.

[0073] Next, as shown in Figure 5 , when the rotary seal ring 20 rotates with respect to the stationary seal ring 101, a flow of the sealed liquid F that is introduced from the opening portion 15a of the positive pressure generating groove 15 to the sealed liquid side toward the front end portion 9a as shown by an arrow H1 occurs, and thus dynamic pressure is generated in the positive pressure generating groove 15. Further, inside the positive pressure generating groove 15, the positive pressure gradually increases as it goes from the opening portion 15a side that is the upstream side to the front end portion 9a that is the downstream side.

[0074] That is, the pressure is highest near the leading end portion 9a at the most upstream side of the positive pressure generating grooves 15, the sliding surfaces 11, 21 are separated from each other, and the sealed liquid F flows out from near the leading end portion 9a to between the sliding surfaces 11, 21 around it as indicated by an arrow H2, thereby forming a liquid film of the sealed liquid F on the sealed liquid side between the sliding surfaces 11, 21. Thus, the liquid film of the sealed liquid F is formed near the leading end portion 9a of the plurality of positive pressure generating grooves 15, thereby becoming so-called fluid lubrication between the sliding surfaces 11, 21, improving lubricity, and realizing low frictionalization. Further, the sealed liquid F slightly flows out to the downstream side from portions other than the leading end portion 9a of the positive pressure generating grooves 15.

[0075] Further, the plurality of leading end portions 9a are arranged on the virtual curve C of the sine wave shape as described above, so that the positive pressure is generated at different positions in the radial direction along the circumferential direction on the sliding surface 11 at the time of relative rotation of the rotary seal ring 20, the radial pressure gradient of the sliding surface 11 is small, and the liquid film is easily formed substantially uniformly over a large area of the sliding surface 11. Thus, the lubricity by the sealed liquid F of the sliding surface 11 is good.

[0076] Further, the sealed liquid F that flows out from the positive pressure generating grooves 15 to the land portion 12 as described above flows into other positive pressure generating grooves 15 arranged in parallel at the downstream side of the positive pressure generating grooves 15 as indicated by an arrow H3, so that the pressure in the positive pressure generating grooves 15 can be stabilized.

[0077] Next, the negative pressure generating groove 171 at the time of relative rotation of the rotary seal ring 20 will be described. When the rotary seal ring 20 rotates relative to the stationary seal ring 10, the negative pressure of the dynamic pressure is generated in the negative pressure generating groove 171, and the sealed liquid F introduced to the atmospheric side end portion 171a side of the negative pressure generating groove 171 flows as indicated by an arrow H4, so that the flow introduced from the atmospheric side end portion 171a of the negative pressure generating groove 171 toward the leading end portion 9a is generated. Further, inside the negative pressure generating groove 171, the pressure gradually becomes higher from the atmospheric side end portion 171a side as the upstream side toward the downstream side, and the atmospheric side end portion 171a becomes a relative negative pressure.

[0078] That is, the pressure is highest near the leading end portion 9a, the sliding surfaces 11, 21 are separated from each other, and the sealed liquid F flows out from near the leading end portion 9a to between the sliding surfaces 11, 21 around it as indicated by an arrow H5, thereby forming a liquid film of the sealed liquid F on the sealed liquid side between the sliding surfaces 11, 21. Thus, the sealed liquid F that flows out from the liquid film flows into the negative pressure generating groove 171 of the other dynamic pressure generating mechanism 141 adjacent at the downstream side. In this way, the sealed liquid F once introduced from the opening portion 15a circulates in the circumferential direction between the plurality of dynamic pressure generating mechanisms 141, so that leakage of the sealed liquid F to the atmospheric side can be prevented.

[0079] In addition, as described above, the plurality of leading end portions 9a arranged on the virtual curve C in the sinusoidal shape circulate along the circumferential direction between the plurality of dynamic pressure generating mechanisms 141 by the sealing liquid F at the time of relative rotation, and thus the gas-liquid interface Yl of the sealing liquid F and the atmosphere A in the sliding surface 11 is formed in a substantially sinusoidal shape on the atmosphere side of the virtual curve C, and the liquid film formation region Y (in Figure 4 indicated by the hatched line in the middle) is formed on the sealing liquid side including a portion of the positive pressure generating groove 15 and the negative pressure generating groove 171 (refer to Figure 4 ). Furthermore, a relative negative pressure is generated on the side of the atmosphere side end portion 171a of the negative pressure generating groove 171, and thus the surrounding sealing liquid F is sucked, and thus it is possible to return the sealing liquid F that is intended to leak to the atmosphere side to the sealing liquid F side on the outer diameter side. In addition, the position of the gas-liquid interface Yl and the range of the liquid film formation region Y vary from the position indicated by the hatched line in the middle due to differences in the rotational speed at the time of relative rotation of the rotary seal ring 20, the pressure of the sealing liquid F, and the like, and it goes without saying. Figure 4

[0080] In addition, as described above, the sealing liquid F that flows out of the negative pressure generating groove 171 to the land portion 12 flows into the other negative pressure generating groove 171 that is arranged in parallel on the downstream side of the negative pressure generating groove 171 as indicated by the arrow H6, and thus it is possible to stabilize the pressure in the negative pressure generating groove 171.

[0081] As described above, the positive pressure generating groove 15 is arranged so as to extend on the atmosphere side and on the downstream side while being inclined, and the negative pressure generating groove 171 that is continuously arranged so as to extend on the atmosphere side and on the upstream side while being inclined from the atmosphere side end portion 9b of the positive pressure generating groove 15 is arranged on the sliding surface. In this way, at the time of relative rotation of the rotary seal ring 20, the negative pressure generating groove 171 that becomes a relative negative pressure sucks the liquid film of the sealing liquid F that is formed in the leading end portion 9a, and thus leakage of the sealing liquid F to the atmosphere side is prevented, and it is possible to improve the sealing performance of the stationary seal ring 10 and the rotary seal ring 20.

[0082] In addition, the land portion 12 is arranged so as to extend in a ring shape on the leakage side of the negative pressure generating groove 171 on the sliding surface 11 in a manner that is continuous in the circumferential direction, and thus the atmosphere side end portion 171a of the negative pressure generating groove 171 is blocked by the land portion 12, and thus it is possible to prevent leakage of the sealing liquid F to the atmosphere side at the time when the rotary seal ring 20 is stationary.

[0083] In addition, the width of the land portion 12 on the atmosphere side from the negative pressure generating groove 171 is fixed in the radial direction in the circumferential direction, and thus the radial position of the atmosphere side end portion 171a of the negative pressure generating groove 171 is fixed in the circumferential direction, and this is easy to manufacture.

[0084] Next, a modification example of the present embodiment will be described. Furthermore, the description that is repeated due to the same configuration as the above-described embodiment will be omitted. As described above, Figure 6 ​As shown, in Modified Example 1, the sliding surface 11 of the stationary sealing ring 101', in addition to the dynamic pressure generating mechanisms 141 arranged in parallel in the circumferential direction as described above, also has a plurality of reverse dynamic pressure generating mechanisms 141' with tips facing the opposite side to the dynamic pressure generating mechanisms 141. The reverse dynamic pressure generating mechanisms 141' have a generally similar structure formed by flipping the dynamic pressure generating mechanisms 141 in the circumferential direction. One side of the V-shape that is open and connected to the sealed liquid side is equivalent to an inverted positive pressure generating groove 15' that is recessed in a straight line with one side facing the atmosphere side and the opposite side to the positive pressure generating groove 15. The other side that is recessed continuously with the inverted positive pressure generating groove 15' is equivalent to an inverted negative pressure generating groove 171' that is recessed in a straight line with one side facing the atmosphere side and the opposite side to the negative pressure generating groove 171, and the tip where the two sides of the V-shape intersect is equivalent to the inverted foremost end 9a'.

[0085] Rotary sealing ring 20 Figure 6 As indicated by the solid arrow, rotating counterclockwise around the paper, i.e., rotating clockwise, the sealed liquid F introduced from the opening 15a in the positive pressure generating tank 15 moves downstream, thereby generating a positive pressure to form a liquid film at the foremost end 9a. The sealed liquid F introduced from the negative pressure generating tank 171 moves downstream, thereby generating a relative negative pressure at the atmospheric end 171a. Additionally, the rotating sealing ring 20... Figure 6 As indicated by the dashed arrow, when rotating clockwise around the paper (i.e., in reverse rotation), the sealed liquid F introduced from the opening 15a' in the positive pressure generating groove 15' moves downstream during the reverse rotation, thereby generating positive pressure at the foremost end 9a' to form a liquid film. Similarly, the sealed liquid F introduced from the negative pressure generating groove 171' moves downstream during the reverse rotation, thereby generating a relative negative pressure at the atmospheric end 171a'. That is, the rotating sealing ring 20 rotates... Figure 6 When the paper is rotated clockwise, the reverse positive pressure generating groove 15' functions as a positive pressure generating groove, and the reverse negative pressure generating groove 171' functions as a negative pressure generating groove.

[0086] Thus, the sliding surface 11 of the stationary sealing ring 101' is provided with a dynamic pressure generating mechanism 141 that faces the downstream side of the relative rotation direction when the tip rotates forward and a reverse dynamic pressure generating mechanism 141' that faces the downstream side of the relative rotation direction when the tip rotates backward, so it can be used regardless of the relative rotation direction of the stationary sealing ring 101 and the rotating sealing ring 20.

[0087] The following explains variation example 2. For example... Figure 7As shown, the plurality of leading end portions 9a and the plurality of upstream-side bent portions 92c where the positive pressure generating grooves 152 and the negative pressure generating grooves 172 intersect are arranged side by side along the circumferential direction, and their radial positions gradually change along the imaginary curve C in a sinusoidal shape, so that the sliding member is easily manufactured.

[0088] Embodiment 3

[0089] Hereinafter, the sliding member according to Embodiment 3 will be described with reference to Figures 8 to 11 , and the description of the configuration common to Embodiment 2 will be omitted.

[0090] As shown in FIG. 6, the sliding surface 11 of the stationary seal ring 103 is uniformly provided with a plurality of dynamic pressure generating mechanisms 143 in the circumferential direction, and the dynamic pressure generating mechanisms 143 are composed of the positive pressure generating grooves 15 extending obliquely toward the atmosphere side and the second positive pressure generating grooves 173 extending obliquely toward the upstream side. Figures 8 to 10

[0091] The positive pressure generating grooves 15 have opening portions 15a open to the sealed liquid side, and are linearly recessed to the blocked atmosphere side end portion 9b, and the leading end portion 9a is arranged at the leading end on the downstream side of the atmosphere side end portion 9b. In addition, the respective leading end portions 9a of the plurality of positive pressure generating grooves 15 arranged side by side along the circumferential direction gradually change in radial position, and are arranged on the smooth and continuous imaginary curve C in a sinusoidal shape along the circumferential direction.

[0092] The second positive pressure generating grooves 173 have opening portions 173a open to the atmosphere side, and are linearly recessed to the blocked sealed liquid side end portion 17b, and the leading end portion 9a is arranged at the leading end on the downstream side of the sealed liquid side end portion 17b. In addition, the radial width of the land portion 12 provided between the positive pressure generating grooves 15 and the second positive pressure generating grooves 173 in the radial direction is formed to have a fixed width along the circumferential direction.

[0093] Hereinafter, the operation when the rotary seal ring 20 rotates will be described. In addition, the operation of the positive pressure generating grooves 15 is the same as in Embodiments 1 and 2, and the description thereof will be omitted as appropriate.

[0094] ​First, when the rotary sealing ring 20 is not rotating and the general industrial machinery is not in operation, the sealed liquid F, which is closer to the sealed liquid side than the sliding surfaces 11 and 21, slightly enters between the sliding surfaces 11 and 21 due to capillary action, and the dynamic pressure generating mechanism 143 is filled with the sealed liquid F flowing in from the opening 15a of the positive pressure generating groove 15. Furthermore, the sealed liquid F has a higher viscosity than gas, so the amount leaking from the dynamic pressure generating mechanism 143 to the atmosphere when the general industrial machinery stops is extremely small.

[0095] Below, as Figure 9 and Figure 10 As shown, when the rotating sealing ring 20 rotates relative to the stationary sealing ring 103, the sealed liquid F on the sealed liquid side flows from the opening 15a of the positive pressure generating tank 15 towards the foremost end 9a, as indicated by arrow H1, thus generating dynamic pressure within the positive pressure generating tank 15. Furthermore, the positive pressure inside the positive pressure generating tank 15 gradually increases from the opening 15a (upstream side) to the foremost end 9a (downstream side).

[0096] That is, the pressure is highest near the foremost end 9a on the downstream side of the positive pressure generating tank 15, where the sliding surfaces 11 and 21 are separated from each other, and the sealed liquid F, as shown by arrow H2, flows out from near the foremost end 9a to the area between the surrounding sliding surfaces 11 and 21, thereby forming a liquid film of sealed liquid F on the sealed liquid side between the sliding surfaces 11 and 21. Thus, a liquid film of sealed liquid F is formed near the foremost end 9a of the plurality of positive pressure generating tanks 15, creating so-called fluid lubrication between the sliding surfaces 11 and 21, improving lubricity, and achieving low friction. Furthermore, the sealed liquid F flows slightly downstream from portions other than the foremost end 9a of the positive pressure generating tank 15.

[0097] Furthermore, the multiple foremost ends 9a are arranged on a sinusoidal virtual curve C as described above. When the rotating sealing ring 20 rotates relative to it, positive pressure is generated at different radial positions along the circumference on the sliding surface 11, and the radial pressure gradient in the sliding surface 11 becomes smaller. Therefore, it is easy to form a liquid film that is approximately uniform in a large area of ​​the sliding surface 11. As a result, the lubrication produced by the sealed liquid F on the sliding surface 11 is good.

[0098] Additionally, as described above, the sealed liquid F flowing from the positive pressure generating tank 15 to the ground portion 12, as indicated by arrow H3, flows into other positive pressure generating tanks 15 arranged parallel to each other downstream of the positive pressure generating tank 15, in the liquid film forming region W (in Figure 8 (As shown by the linear shading.) A liquid film of roughly uniform thickness is formed.

[0099] The second positive pressure generating groove 173 when the rotary sealing ring 20 rotates relative to the surrounding area will be described below. Figure 9As shown, when the rotating seal ring 20 rotates relative to the stationary seal ring 103, the atmosphere A on the atmospheric side flows as indicated by arrow LI from the opening portion 173a of the second positive pressure generation groove 173 toward the second forwardmost end portion 17a, and dynamic pressure is generated in the second positive pressure generation groove 173. Further, inside the second positive pressure generation groove 173, the positive pressure gradually increases from the opening portion 173a side as the upstream side toward the second forwardmost end portion 17a as the downstream side.

[0100] That is, the pressure is highest near the second forwardmost end portion 17a, which is located at the downstream side of the second positive pressure generation groove 173, the sliding surfaces 11, 21 are separated from each other, and the atmosphere A flows as indicated by arrow L2 from near the second forwardmost end portion 17a to between the sliding surfaces 11, 21 around the second forwardmost end portion 17a. In this way, the positive pressure is generated near the second forwardmost end portion 17a, whereby the sealed liquid F that approaches near the second forwardmost end portion from the sealed liquid side can be bounced back, and leakage of the sealed liquid F to the atmospheric side is prevented.

[0101] In addition, as described above, in addition to the liquid film formed when the rotating seal ring 20 rotates relative to the stationary seal ring 103 among the plurality of forwardmost end portions 9a arranged on the virtual curve C in the sine wave shape, the positive pressure generated when the rotating seal ring 20 rotates relative to the stationary seal ring 103 due to the concentration of the atmosphere A in the plurality of second forwardmost end portions 17a does not cause the liquid film to enter the atmospheric side, and therefore the gas-liquid interface Wl of the sealed liquid F and the atmosphere A in the sliding surface 11 is formed in the sine wave shape between the plurality of atmospheric side end portions 9b and the plurality of sealed liquid side end portions 17b, and the liquid film formation region W is formed on the sealed liquid side including the positive pressure generation groove 15 (refer to FIG. 9). Figure 8 In addition, the position of the gas-liquid interface Wl and the range of the liquid film formation region W vary from the position shown in FIG. 9 depending on the rotational speed when the rotating seal ring 20 rotates relative to the stationary seal ring 103, the pressure of the sealed liquid F, and the like, without saying. Figure 8

[0102] First, a case where the sealed liquid F does not enter the land portion 12 on the atmospheric side when the rotating seal ring 20 rotates relative to the stationary seal ring 103 will be described. A portion of the atmosphere A in the second positive pressure generation groove 173 follows the relative rotation of the rotating seal ring 20, and flows out at the land portion 12 on the downstream side where the pressure is increased, whereby the gas-liquid interface Wl is maintained between the positive pressure generation groove 15 and the second positive pressure generation groove 173 as shown in FIG. 9, and the sealed liquid F that wants to enter the second positive pressure generation groove 173 side is prevented. Figure 8

[0103] Next, a case where the sealed liquid F enters the land portion 12 on the atmospheric side when the rotating seal ring 20 rotates relative to the stationary seal ring 103 will be described. As shown in FIG. 10, the sealed liquid F that wants to enter the second positive pressure generation groove 173 side is prevented by the gas-liquid interface Wl that is maintained between the positive pressure generation groove 15 and the second positive pressure generation groove 173 as shown in FIG. 9. Figure 10 ​​As shown, the atmosphere A on the atmospheric side is introduced from the opening portion 173a of the second positive pressure generation groove 173 toward the second front end portion 17a as indicated by an arrow L3, and is introduced from the land portion 12 as indicated by an arrow H9, and in the flow of the atmosphere A indicated by the arrow L3, the sealed liquid F is merged, and the flow of the sealed liquid F toward the second front end portion 17a as indicated by an arrow H7 is generated, and dynamic pressure is generated in the second positive pressure generation groove 173. Further, as in the case of the positive pressure generation groove 15, the inside of the second positive pressure generation groove 173 gradually becomes higher in pressure from the upstream side opening portion 173a toward the second front end portion 17a on the downstream side. Figure 9

[0104] That is, the pressure is the highest in the vicinity of the second front end portion 17a that is the front end on the downstream side of the second positive pressure generation groove 173, and the sealed liquid F flows out from the vicinity of the second front end portion 17a to between the sliding surfaces 11, 21 on the periphery thereof as indicated by an arrow H8. In this way, the sealed liquid F that has entered the land portion 12 is returned to the sealed liquid side on the outer diameter side, and leakage of the sealed liquid F to the atmospheric side can be prevented. Further, the sealed liquid F has incompressibility and high viscosity as compared with the atmosphere, and therefore the sealed liquid F that has entered the second positive pressure generation groove 173 easily flows out to between the sliding surfaces 11, 21 in conjunction with the relative rotation of the rotary seal ring 20.

[0105] As described above, the second positive pressure generation groove 173 is provided on the atmospheric side of the positive pressure generation groove 15, the second positive pressure generation groove 173 is independent of the positive pressure generation groove 15, and when the rotary seal ring 20 relatively rotates, the atmosphere on the atmospheric side of the positive pressure generation groove 15 is introduced to generate positive pressure, and the second front end portion 17a is provided at the front end on the downstream side in the direction of relative rotation of the second positive pressure generation groove 173. In this way, the atmosphere on the atmospheric side flows to the downstream side of the second positive pressure generation groove 173 at the time of relative rotation of the rotary seal ring 20, and positive pressure is generated by being concentrated on the second front end portion 17a, and therefore the sealed liquid F that has approached the vicinity of the second front end portion 17a from the sealed liquid side can be bounced back, and leakage of the sealed liquid F to the atmospheric side can be prevented.

[0106] Further, the second positive pressure generation groove 173 is arranged in correspondence with the number and positions of the positive pressure generation grooves 15, and therefore the second positive pressure generation groove 173 can be machined in correspondence with the number and positions of the positive pressure generation grooves 15, and manufacturing is facilitated.

[0107] Further, the land portion 12 is annularly provided between the radial directions of the positive pressure generation groove 15 and the second positive pressure generation groove 173, the positive pressure generation groove 15 and the second positive pressure generation groove 173 can be separated, and the functions of the two at the time of relative rotation can be made clear.

[0108] ​In addition, the radial width of the land portion 12 provided between the radial direction of the positive pressure generation groove 15 and the second positive pressure generation groove 173 is fixed in the circumferential direction, and thus the second forward end portion 17a is separated from the forward end portion 9a by a fixed size toward the leakage side, and the second forward end portion 17a that generates positive pressure at the time of relative rotation is arranged at a position of a different diameter length in the circumferential direction, and thus it is possible to prevent the sealed liquid F flowing from the liquid film generated at the forward end portion 9a from entering the atmosphere side at the time of relative rotation.

[0109] Hereinafter, a modification will be described. Furthermore, the description of the same configuration as the above-described embodiment will be omitted. As shown in FIG. 9, in the modification 3, the forward end portion 9a and the corner portion 9c located on the upstream side of the atmospheric side end portion 9b of the positive pressure generation groove 154 are arranged in parallel on the sliding surface 11 of the stationary seal ring 104, and the radial positions thereof are gradually changed along the circumferential direction, and are arranged on the virtual curve C in a sinusoidal shape, and thus it is easy to manufacture. Figure 11

[0110] The above describes the embodiment of the present application according to the drawings, but the specific configuration is not limited to these embodiments, and even if there is a change or addition within the range of the gist of the present application, it is included in the present application.

[0111] For example, in the above-described embodiment, the mechanical seal for general industrial machinery is described as an example of the sliding member, but it can be another mechanical seal such as a mechanical seal for an automobile or a water pump. In addition, it is not limited to the mechanical seal, and it can be a sliding member other than the mechanical seal such as a sliding bearing.

[0112] In addition, in the above-described embodiment, the example in which the dynamic pressure generation mechanism is provided only in the stationary seal ring 10 is described, but the dynamic pressure generation mechanism can be provided only in the rotating seal ring 20, or it can be provided in both the stationary seal ring and the rotating seal ring.

[0113] In addition, in the above-described embodiment, the forward end portion 9a and the corner portion 9c or the bent portion 92c are arranged on the virtual curve C in a sinusoidal shape that is smooth and continuous, but it is not limited thereto, and the virtual curve can be, for example, a wavy shape or a rectangular wave shape with a small period.

[0114] In addition, in the above-described embodiment, the positive pressure generation groove 15, the negative pressure generation groove, the inverted positive pressure generation groove 15', the inverted negative pressure generation groove 171', and the second positive pressure generation groove 173 are concave in a straight line shape, but it is not limited thereto, and it can be concave in a curved shape, for example.

[0115] In addition, the positive pressure generation groove has an opening portion 15a that is open to the sealed liquid side, but it is not limited thereto, and it can be plugged without being open.

[0116] ​Further, the second positive pressure generating groove 173 is provided with an opening portion 173a that is open to the atmosphere, but is not limited thereto and can be closed without being open.

[0117] Symbol explanation

[0118] 1, rotating shaft; 2, sleeve; 4, housing; 5, seal cover; 7, bellows; 9a, foremost end portion; 9b, atmospheric side end portion (leakage side end portion); 9c, corner portion; 10, stationary seal ring (sliding member); 11, sliding surface; 12, ground portion; 14, dynamic pressure generating mechanism; 15, positive pressure generating groove; 15a, opening portion; 17a, second foremost end portion; 20, rotating seal ring (sliding member); 21, sliding surface; 92c, bent portion; 171, negative pressure generating groove; 173, second positive pressure generating groove.

Claims

1. A sliding member that is a ring-shaped sliding member configured at a relative rotation portion of a rotary machine, wherein a plurality of positive pressure generating grooves are provided in parallel along a circumferential direction on a sliding surface of the sliding member, the positive pressure generating grooves are introduced with a sealed fluid on a sealed fluid side to generate a positive pressure when the rotary machine is relatively rotated, each of the positive pressure generating grooves has a leading end portion at a leading end on a downstream side in a relative rotation direction, at least a part of the leading end portions provided in parallel along the circumferential direction is configured at different positions in a radial direction, each of the positive pressure generating grooves is formed to extend from the sealed fluid side to a leakage side and to be inclined toward the downstream side in the relative rotation direction, the leading end portions provided in parallel along the circumferential direction gradually change in the radial direction, a land portion is formed between at least one of the positive pressure generating grooves and an adjacent positive pressure generating groove on an upstream side in the relative rotation direction and between the at least one of the positive pressure generating grooves and an adjacent positive pressure generating groove on a downstream side in the relative rotation direction, and the greater the extension direction length of the positive pressure generating groove, the smaller the inclination angle of the positive pressure generating groove with respect to the radial direction.

2. The sliding member according to claim 1, wherein the leading end portions provided in parallel along the circumferential direction are regularly configured along the circumferential direction.

3. The sliding member according to claim 1 or 2, wherein the leading end portions provided in parallel along the circumferential direction are configured in a wave shape.

4. The sliding member according to claim 1 or 2, wherein the positive pressure generating groove has an opening portion that communicates with the sealed fluid side.

5. The sliding member according to claim 1 or 2, wherein the positive pressure generating groove is provided while being inclined toward the downstream side in the relative rotation direction on the leakage side, a negative pressure generating groove is provided on the sliding surface, the negative pressure generating groove is provided while being continuously inclined toward an upstream side in the relative rotation direction on the leakage side from a leakage side end portion of the positive pressure generating groove.

6. The sliding member according to claim 5, wherein a land portion extending in the circumferential direction is provided on the sliding surface on the leakage side from the negative pressure generating groove.

7. The sliding member according to claim 6, wherein the land portion on the leakage side from the negative pressure generating groove is fixed in the circumferential direction in the radial direction.

8. The sliding member according to claim 5, wherein the leading end portions provided in parallel along the circumferential direction and a bent portion on the upstream side in the relative rotation direction at which the positive pressure generating groove and the negative pressure generating groove intersect are gradually changed in the radial direction along the circumferential direction and are configured in a wave shape.

9. The sliding member according to claim 1 or 2, wherein a second positive pressure generating groove is provided on the sliding surface, the second positive pressure generating groove is independent of the positive pressure generating groove on the leakage side from the positive pressure generating groove, is introduced with a fluid on the leakage side from the positive pressure generating groove to generate a positive pressure when the rotary machine is relatively rotated, and has a second leading end portion at a leading end on the downstream side in the relative rotation direction.

10. The sliding member according to claim 9, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The second positive pressure generating groove is arranged corresponding to the number and position of the positive pressure generating grooves.

11. The sliding member according to claim 10, wherein A land extending in the circumferential direction is provided between the positive pressure generating groove and the second positive pressure generating groove in the radial direction.

12. The sliding member according to claim 11, wherein The radial width of the land provided between the positive pressure generating groove and the second positive pressure generating groove in the radial direction is fixed in the circumferential direction.

13. The sliding member according to claim 3, wherein The radially positions of the leading end portions and the corner portions located on the upstream side of the relative rotation direction at the leakage side end portions of the positive pressure generating grooves gradually change along the circumferential direction, and are arranged in a wave shape.

14. A sliding member that is a ring-shaped sliding member arranged at a relative rotation portion of a rotary machine, wherein A plurality of first positive pressure generating grooves are arranged in parallel along the circumferential direction on a sliding surface of the sliding member, the first positive pressure generating grooves are introduced into a sealed fluid on the sealed fluid side by a sealed fluid when the sliding member is relatively rotated to generate a positive pressure, each of the first positive pressure generating grooves has a first leading end at a leading end on the downstream side of the relative rotation direction, and at least a portion of the first leading ends arranged in parallel along the circumferential direction is arranged at different positions along the radial direction; A plurality of second positive pressure generating grooves are also arranged in parallel along the circumferential direction on the sliding surface, the second positive pressure generating grooves are introduced into a fluid on the leakage side from the first positive pressure generating grooves and independently from the first positive pressure generating grooves when the rotary machine is relatively rotated to generate a positive pressure, the second positive pressure generating grooves have a second leading end at a leading end on the downstream side of the relative rotation direction, and at least a portion of the second leading ends arranged in parallel along the circumferential direction is arranged at different positions along the radial direction; The radially positions of the first leading ends arranged in parallel along the circumferential direction gradually change, A land is formed between at least one of the first positive pressure generating grooves and an adjacent first positive pressure generating groove on the upstream side of the relative rotation direction, and between the at least one of the first positive pressure generating grooves and an adjacent first positive pressure generating groove on the downstream side of the relative rotation direction, and The greater the length of the first positive pressure generating grooves in the extending direction, the smaller the inclination angle of the first positive pressure generating grooves with respect to the radial direction.

15. The sliding member according to claim 14, wherein The first leading ends arranged in parallel along the circumferential direction are regularly arranged.

16. The sliding member according to claim 15, wherein The first leading ends arranged in parallel along the circumferential direction are arranged in a wave shape.

17. The sliding member according to claim 14, wherein The second leading ends arranged in parallel along the circumferential direction are regularly arranged.

18. The sliding member according to claim 15, wherein The radially positions of the second leading ends arranged in parallel along the circumferential direction gradually change, and the second leading ends are arranged in a wave shape.

19. The sliding member according to claim 14, wherein The first positive pressure generation groove has an opening portion that communicates with the sealed fluid side.

20. The sliding member according to claim 14, wherein The second positive pressure generation groove has an opening portion that communicates with the leakage side.

21. The sliding member according to claim 14 or 15, wherein The first positive pressure generation groove is disposed extending obliquely toward the leakage side and toward the downstream side in the relative rotation direction.

22. The sliding member according to claim 14 or 15, wherein The second positive pressure generation groove is disposed extending obliquely toward the sealed fluid side and toward the downstream side in the relative rotation direction.

23. The sliding member according to claim 14 or 15, wherein The second positive pressure generation groove is disposed corresponding to the number and position of the first positive pressure generation groove.

24. The sliding member according to claim 14 or 15, wherein A land portion extending in the circumferential direction is provided between the first positive pressure generation groove and the second positive pressure generation groove in the radial direction.

25. The sliding member according to claim 24, wherein The width of the land portion provided between the first positive pressure generation groove and the second positive pressure generation groove in the radial direction is fixed in the circumferential direction.

26. The sliding member according to claim 14 or 15, wherein The first frontmost end portion and the corner portion located on the upstream side in the relative rotation direction from the leakage side end portion of the first positive pressure generation groove, which are provided in plurality, are disposed in a wave shape in which the radial position thereof changes gradually along the circumferential direction.

Images