Sliding member

Abstract

The present invention provides a sliding member which has high sealing performance when the sliding member rotates relatively forward, and which can sufficiently lubricate sliding surfaces when the sliding member rotates relatively backward. The sliding surface of at least one of the sliding members is provided with: a forward-direction dynamic pressure generation groove (13) that communicates with the leak space (S2); a forward fluid introduction / discharge groove (18) which is separated from the forward dynamic pressure generation groove (13) by a shoulder section and which communicates with the sealed fluid space (S1); and a reverse fluid introduction / discharge groove (18 ') that is separated from the forward dynamic pressure generation groove (13) by a shoulder section and that communicates with the sealed fluid space (S1), the forward dynamic pressure generation groove (13) being disposed in a state that is sparse relative to the reverse fluid introduction / discharge groove (18') than the forward fluid introduction / discharge groove (18).

Description

Technical Field

[0001] The present invention relates to a relatively rotating sliding component, for example, a sliding component used in a shaft sealing device for sealing a rotating shaft of a rotating machine in an automobile, general industrial machinery, or other sealing fields, or a sliding component used in a bearing of an automobile, general industrial machinery, or other bearing-related machinery. Background Art

[0002] As a shaft sealing device for preventing leakage of a sealed fluid, for example, a mechanical seal includes a pair of annular sliding members that rotate relatively and slide on sliding surfaces. In recent years, in such a mechanical seal, it has been desired to reduce energy lost due to sliding for environmental protection and the like.

[0003] For example, the mechanical seal shown in Patent Document 1 is provided with a dynamic pressure generating groove and a fluid introduction groove on the stationary sealing ring. The starting end of the dynamic pressure generating groove is connected to the internal space on the leakage side, and the dynamic pressure generating groove extends in an arc shape from the starting end toward the outer diameter side in the positive rotation direction of the rotating sealing ring, and multiple dynamic pressure generating grooves are evenly arranged along the circumferential direction. In addition, the fluid introduction groove is composed of the following parts: a fluid guide groove portion, which is connected to the external space; and a Rayleigh step, which extends circumferentially concentrically with the stationary sealing ring from the inner diameter side of the fluid guide groove portion toward the positive rotation direction of the rotating sealing ring. There is a sealed fluid in the external space, and there is atmosphere in the internal space.

[0004] When the rotating seal ring rotates forward at a low speed, the positive pressure generated at the terminal of the Rayleigh step of the fluid introduction groove and its vicinity causes the sliding surfaces to be slightly separated from each other and the sealed fluid to flow in, thereby lubricating the sliding surfaces to each other, which can suppress the wear of the sliding surfaces, and the positive pressure generated at the terminal side of the dynamic pressure generating groove causes the sealed fluid flowing between the sliding surfaces to be pressed back to the external space side, thereby suppressing the leakage of the sealed fluid from between the sliding surfaces to the internal space. In addition, when the rotating seal ring rotates forward at a high speed, the positive pressure generating capacity of the dynamic pressure generating groove as a whole is greater than the positive pressure generating capacity of the Rayleigh step as a whole, and gas lubrication can be performed.

[0005] In the sliding part of the cited document 1, the lubricity is improved only when the rotating seal ring rotates forward, but there are also mechanical seals in which the rotating seal ring rotates reversely depending on the environment in which it is used. In such mechanical seals, it is required to improve the lubricity also when the rotating seal ring rotates reversely. Therefore, it is considered to further form a reverse Rayleigh step extending circumferentially from the inner diameter side of the fluid guide groove portion of the fluid introduction groove toward the reverse direction of the rotating seal ring and concentrically with the stationary seal ring (for example, refer to patent document 2). As a result, when the rotating seal ring rotates reversely, the sliding surfaces are lubricated by the sealed fluid flowing from the terminal of the reverse Rayleigh step to between the sliding surfaces, and the wear between the sliding surfaces can be suppressed.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2016 / 167262 (page 13, Figure 7 )

[0009] Patent Document 2: International Publication No. 2020 / 162348 (page 8, Figure 6 ) Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, although Patent Document 2 can improve lubricity with respect to any rotation direction, the sealing performance during forward rotation is insufficient. Therefore, when the fluid inlet groove with a reverse Rayleigh step such as Patent Document 2 is applied to Patent Document 1, the dynamic pressure generating groove has a pressure-return effect on the sealed fluid, so leakage during forward rotation can be reduced. On the other hand, during reverse rotation, the sealed fluid in the fluid inlet groove flowing out from the terminal and the vicinity of the reverse Rayleigh step will be immediately sucked into the dynamic pressure generating groove from the terminal side, and the pressure of the sealed fluid flowing out from the terminal and the vicinity of the reverse Rayleigh step of the fluid inlet groove will decrease, and it may be impossible to form a gap between the sliding surfaces sufficient for the sealed fluid to flow in.

[0012] The present invention has been made in view of such problems, and an object of the present invention is to provide a sliding component which has high sealing performance during relative forward rotation and can sufficiently lubricate sliding surfaces during relative reverse rotation.

[0013] Means for solving problems

[0014] In order to solve the above-mentioned problems, the sliding component of the present invention is:

[0015] The sliding surfaces of a pair of sliding rings rotate relative to each other and divide the sealed fluid space and the leakage space.

[0016] The sliding surface of at least one of the slide surfaces includes: a positive dynamic pressure generating groove, which is connected to the leakage space; a positive fluid introduction and deduction groove, which is separated from the positive dynamic pressure generating groove by a shoulder portion and is connected to the sealed fluid space; and a reverse fluid introduction and deduction groove, which is separated from the positive dynamic pressure generating groove by a shoulder portion and is connected to the sealed fluid space.

[0017] The positive direction dynamic pressure generating grooves are arranged more sparsely with respect to the negative direction fluid introduction and outlet grooves than with respect to the positive direction fluid introduction and outlet grooves.

[0018] Thus, when the sliding part rotates forward relative to the other, the interface between the sealed fluid and the fluid in the leakage space, such as the gas-liquid interface, is located on the sealed fluid space side, so the sealing performance is high. In addition, the positive dynamic pressure generating groove is arranged in a more sparse state relative to the reverse fluid introduction and derivation groove, so when the sliding part is reversed relative to the other, the sealed fluid is not easy to flow from the reverse fluid introduction and derivation groove to the positive dynamic pressure generating groove, so that pressure is easily generated at the terminal of the reverse fluid introduction and derivation groove and the shoulder portion near it, and a gap sufficient for the sealed fluid to flow in can be formed between the sliding surfaces, so that the sliding surfaces can be fully lubricated with each other.

[0019] The terminal ends of the positive direction dynamic pressure generating grooves may be arranged more sparsely with respect to the terminal ends of the negative direction fluid introduction and outlet grooves than with respect to the terminal ends of the positive direction fluid introduction and outlet grooves.

[0020] Therefore, when positive pressure is generated in the reverse fluid inlet and outlet groove during relative reversal, the negative pressure generated on the terminal side of the positive dynamic pressure generating groove has a smaller impact, so pressure is easily generated at the terminal of the reverse fluid inlet and outlet groove and the shoulder near it.

[0021] The rarefaction state may be formed by arranging the forward dynamic pressure generating grooves having a smaller total volume relative to the reverse fluid introduction and discharge grooves than relative to the forward fluid introduction and discharge grooves.

[0022] Therefore, a positive dynamic pressure generating groove with a smaller total volume is configured relative to the reverse fluid inlet and outlet grooves, so that positive pressure is also generated through the positive dynamic pressure generating groove. As a result, dynamic pressure can be reliably generated during relative positive rotation, and leakage of the sealed fluid during relative positive rotation can be reliably prevented.

[0023] The rarefaction state may be formed by arranging the positive direction dynamic pressure generating groove shorter in the radial direction with respect to the negative direction fluid introduction and discharge groove than with respect to the positive direction fluid introduction and discharge groove.

[0024] Therefore, a radially shorter positive dynamic pressure generating groove is configured relative to the reverse fluid inlet and outlet groove, so that positive pressure is also generated through the positive dynamic pressure generating groove. As a result, dynamic pressure can be reliably generated during relative positive rotation, and leakage of the sealed fluid during relative positive rotation can be reliably prevented.

[0025] A plurality of regions in the sparse state may be arranged in the circumferential direction of the sliding surface.

[0026] Thus, during relative inversion, pressure is easily generated at the shoulder portions near the reverse fluid introduction and discharge grooves at a plurality of locations in the circumferential direction of the sliding surfaces, and the sliding surfaces can be sufficiently lubricated to each other.

[0027] It can also be that the positive dynamic pressure generating groove is a spiral groove extending in an arc shape from the starting end at an inclination relative to the radial direction, the positive fluid inlet and outlet groove has a fluid guide groove portion connected to the sealed fluid space and a Rayleigh step extending along the relative positive rotation direction, and the reverse fluid inlet and outlet groove has a fluid guide groove portion connected to the sealed fluid space and a reverse Rayleigh step extending along the relative reverse direction.

[0028] Thus, the positive dynamic pressure generating groove is a spiral groove, so that the positive pressure can be efficiently generated at the terminal using the fluid such as gas on the leakage space side. In addition, the Rayleigh step and the reverse Rayleigh step extend in the relative forward rotation direction or the relative reverse rotation direction, so that during relative forward rotation and relative reverse rotation, most of the sealed fluid flows out from the terminal of the Rayleigh step or the terminal of the reverse Rayleigh step toward the circumferential direction, and is therefore not easily sucked from the terminal of the positive dynamic pressure generating groove.

[0029] The forward fluid introduction and outlet groove and the reverse fluid introduction and outlet groove may be substantially T-shaped and share the fluid guide groove portion.

[0030] Therefore, in either the relative forward rotation or the relative reverse rotation, in addition to the sealed fluid in the fluid guide groove, the sealed fluid in the Rayleigh step on the other side when positive pressure is generated on one side can also be utilized, so that a sufficient amount of sealed fluid can be used to efficiently generate positive pressure.

[0031] The forward-direction fluid introduction and outlet groove may be arranged on the reverse direction side of the reverse-direction fluid introduction and outlet groove.

[0032] Thus, part of the sealed fluid flowing into the sliding surfaces from the terminal end of the reverse fluid introduction and outlet groove is sucked and recovered from the terminal end of the reverse fluid introduction and outlet groove adjacent in the rotational direction, and is less likely to leak into the external space serving as the leakage space.

[0033] Furthermore, the sealed fluid may be a gas or a liquid, or may be a mist formed by a mixture of liquid and gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a longitudinal sectional view showing an example of a mechanical seal in Embodiment 1 of the present invention;

[0035] Figure 2 is a diagram of the sliding surface of the stationary seal ring in Example 1 observed from the axial direction;

[0036] Figure 3 is an enlarged view of the sliding surface of the stationary seal ring in Example 1 observed from the axial direction;

[0037] Figure 4This is an explanatory diagram of the movement of the fluid in the dynamic pressure generating groove and the fluid introduction groove when the sliding surface of the stationary seal ring in the first embodiment is viewed from the axial direction during normal rotation;

[0038] Figure 5 It is an explanatory diagram of the movement of the fluid in the dynamic pressure generating groove and the fluid introducing groove when the sliding surface of the stationary seal ring in the first embodiment is viewed from the axial direction in the counter-rotation;

[0039] Figure 6 is an enlarged view of the sliding surface of the stationary seal ring in Example 2 of the present invention observed from the axial direction;

[0040] Figure 7 is an enlarged view of the sliding surface of the stationary seal ring in Example 3 of the present invention observed from the axial direction;

[0041] Figure 8 is an enlarged view of the sliding surface of the stationary seal ring in Example 4 of the present invention observed from the axial direction;

[0042] Fig. 9 This is a diagram showing the sliding surface of the stationary seal ring in Example 5 of the present invention as viewed from the axial direction;

[0043] Fig.10 is a diagram showing the sliding surface of the stationary seal ring in Example 6 of the present invention as viewed from the axial direction;

[0044] Fig.11 is a diagram showing the sliding surface of the stationary seal ring in Example 7 of the present invention as viewed from the axial direction;

[0045] Fig.12 This is a diagram showing a sliding surface of a stationary seal ring in a modified example of the first embodiment of the present invention as viewed from the axial direction. DETAILED DESCRIPTION

[0046] Hereinafter, modes for implementing the sliding member of the present invention will be described based on examples.

[0047] [Example 1]

[0048] Reference Figures 1 to 5 The sliding component of Example 1 is described. In addition, in this embodiment, the sliding component is a mechanical seal. In addition, there is a sealed fluid in the internal space of the mechanical seal, and there is air in the external space. The inner diameter side of the sliding component constituting the mechanical seal is described as the sealed fluid side (high pressure side), and the outer diameter side is described as the leakage side (low pressure side). In addition, for the convenience of description, in the drawings, points are sometimes marked on grooves formed on the sliding surface.

[0049] Figure 1The automotive mechanical seal shown is an outer-type mechanical seal that seals the sealed fluid F that leaks from the inner diameter side to the outer diameter side of the sliding surface, and the external space S2 is connected to the atmosphere A. In addition, in this embodiment, the sealed fluid F is a high-pressure liquid, and the atmosphere A is a gas with a lower pressure than the sealed fluid F.

[0050] The mechanical seal is mainly composed of an annular rotating seal ring 20 as another sliding component and an annular stationary seal ring 10 as a sliding component. The rotating seal ring 20 is arranged on the rotating shaft 1 via the sleeve 2 so as to be able to rotate together with the rotating shaft 1. The stationary seal ring 10 is arranged on the sealing cover 5 fixed to the housing 4 of the mounted device in a non-rotating state and axially movable state. The stationary seal ring 10 is urged in the axial direction by the elastic component 7, and the sliding surface 11 of the stationary seal ring 10 and the sliding surface 21 of the rotating seal ring 20 slide in close contact with each other. In addition, the sliding surface 21 of the rotating seal ring 20 is a flat surface, and no recessed parts such as grooves are provided on the flat surface.

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

[0052] like Figure 2 and Figure 3 As shown, the rotating seal ring 20 as the counterpart seal ring slides counterclockwise as indicated by the solid arrow or clockwise as indicated by the dotted arrow relative to the stationary seal ring 10. In the following description, the rotation direction of the solid arrow is referred to as the forward rotation direction, and the rotation direction of the dotted arrow is referred to as the reverse rotation direction.

[0053] On the sliding surface 11 of the stationary seal ring 10, a plurality of dynamic pressure generating grooves 13 are evenly arranged along the circumferential direction on the outer diameter side, and a plurality of fluid introduction grooves 16 as fluid introduction and deflection grooves are evenly arranged along the circumferential direction on the inner diameter side. In this embodiment, the fluid introduction grooves 16 have the function of introducing fluid, but can also be used to deflect fluid.

[0054] In addition, the portion of the sliding surface 11 other than the dynamic pressure generating groove 13 and the fluid introduction groove 16 is formed into a shoulder 12 having a flat surface (see Figure 2 ). In detail, Figure 3 As shown, the shoulder 12 has a shoulder portion 12a between circumferentially adjacent dynamic pressure generating grooves 13, a shoulder portion 12b between circumferentially adjacent fluid inlet grooves 16, a shoulder portion 12c and a shoulder portion 12d described later, and the upper surfaces (i.e., axial end surfaces) of each of these shoulder portions are arranged in the same plane, constituting a flat surface of the shoulder 12.

[0055] like Figure 2 As shown, the starting end of the dynamic pressure generating groove 13 is connected to the external space S2, and the dynamic pressure generating groove 13 extends in an arc shape from the starting end toward the inner diameter side in the forward rotation direction of the rotating seal ring 20. The dynamic pressure generating groove 13 is a positive dynamic pressure generating groove that generates positive pressure at the terminal end when the rotating seal ring 20 rotates forward.

[0056] The dynamic pressure generating groove 13 includes a first dynamic pressure generating groove 131 which is relatively long in the radial direction and has a terminal end 131a (see Figure 3 ) is closer to the fluid introduction groove 16; and a second dynamic pressure generating groove 132, which is shorter in the radial direction than the first dynamic pressure generating groove 131, and the terminal 132a (reference Figure 3 ) is further away from the fluid introduction groove 16.

[0057] The first dynamic pressure generating grooves 131 and the second dynamic pressure generating grooves 132 respectively constitute a first dynamic pressure generating groove group and a second dynamic pressure generating groove group by a predetermined number. In this embodiment, the first dynamic pressure generating groove group is constituted by six first dynamic pressure generating grooves 131 in the circumferential direction, and the second dynamic pressure generating groove group is constituted by three second dynamic pressure generating grooves 132 in the circumferential direction, and these first dynamic pressure generating groove groups and second dynamic pressure generating groove groups are alternately arranged.

[0058] In addition, the adjacent first dynamic pressure generating grooves 131 and the second dynamic pressure generating grooves 132 are separated by the same distance as the circumferential separation distance between the first dynamic pressure generating grooves 131 and the circumferential separation distance between the second dynamic pressure generating grooves 132. That is, the first dynamic pressure generating grooves 131 and the second dynamic pressure generating grooves 132 are all evenly arranged in the circumferential direction, that is, arranged at equal intervals, but the present invention is not limited thereto, and the adjacent first dynamic pressure generating grooves 131 and the second dynamic pressure generating grooves 132 may be separated by a distance different from the circumferential separation distance between the first dynamic pressure generating grooves 131 and the circumferential separation distance between the second dynamic pressure generating grooves 132.

[0059] Furthermore, the dynamic pressure generating groove 13 is not limited to extending in an arc shape inclined in the normal rotation direction of the rotary seal ring 20 , and may extend in a linear shape inclined in the normal rotation direction of the rotary seal ring 20 , for example.

[0060] like Figure 3 As shown, the fluid inlet groove 16 is composed of the following parts: a fluid guide groove portion 17, which is connected to the internal space S1; and a Rayleigh step 18 and a reverse Rayleigh step 18' as a dynamic pressure generating portion, which extend circumferentially from the outer diameter side of the fluid guide groove portion 17 toward the forward rotation direction or reverse rotation direction of the rotating seal ring 20 concentrically with the stationary seal ring 10.

[0061] In addition, the fluid guide groove 17 is formed to be deeper than the depth dimension of the dynamic pressure generating groove 13. In addition, the Rayleigh step 18 and the reverse Rayleigh step 18' are formed to be shallower than the depth dimension of the fluid guide groove 17 and to be substantially the same depth dimension as the depth dimension of the dynamic pressure generating groove 13. In addition, the fluid guide groove 17 may also be the same depth dimension as the dynamic pressure generating groove 13. In addition, the Rayleigh step 18 and the reverse Rayleigh step 18' are formed to have a circumferential length longer than the circumferential length of the fluid guide groove 17 and the circumferential length of one dynamic pressure generating groove 13.

[0062] The Rayleigh step 18 extends circumferentially concentrically with the stationary seal ring 10 toward the forward rotation direction of the rotating seal ring 20, and together with the fluid guide groove 17, forms a forward fluid introduction and deduction groove. The reverse Rayleigh step 18' extends circumferentially concentrically with the stationary seal ring 10 toward the reverse rotation direction of the rotating seal ring 20, and together with the fluid guide groove 17, forms a reverse fluid introduction and deduction groove.

[0063] In addition, the fluid introduction groove 16 is arranged in a radially inner position than the first dynamic pressure generating groove group and the second dynamic pressure generating groove group so as to straddle them, in other words, arranged opposite to them in the radial direction. Specifically, the terminal 131a of the first dynamic pressure generating groove 131Z at the rearmost end adjacent to the second dynamic pressure generating groove 132, i.e., the upstream end in the normal rotation direction, of the first dynamic pressure generating groove 131 constituting the first dynamic pressure generating groove group is opposite to the fluid guide groove portion 17 of the fluid introduction groove 16. In other words, the fluid guide groove portion 17 is located in the extension direction of the terminal 131a of the rearmost first dynamic pressure generating groove 131Z.

[0064] The terminal 131a of the front-end first dynamic pressure generating groove 131A of the first dynamic pressure generating groove 131 constituting the first dynamic pressure generating groove group is located slightly on the outer diameter side than the shoulder 12b between the circumferentially adjacent fluid introduction grooves 16. In addition, all the first dynamic pressure generating grooves 131 constituting the first dynamic pressure generating groove group are formed toward the shoulder 12b, the Rayleigh step 18, and the fluid guide groove 17 between the circumferentially adjacent fluid introduction grooves 16, and are not opposite to the reverse Rayleigh step 18'. In other words, the reverse Rayleigh step 18' is not located in the extension direction of the terminal 131a of the rear-end first dynamic pressure generating groove 131Z.

[0065] In contrast, the terminal 132a of the front-end second dynamic pressure generating groove 132A adjacent to the first dynamic pressure generating groove 131 in the second dynamic pressure generating groove 132 constituting the second dynamic pressure generating groove group is opposite to the reverse Rayleigh step 18' of the fluid inlet groove 16. In other words, the reverse Rayleigh step 18' is located in the extension direction of the terminal 132a of the front-end second dynamic pressure generating groove 132A. In addition, the terminal 132a of the rear-end second dynamic pressure generating groove 132Z in the second dynamic pressure generating groove 132 constituting the second dynamic pressure generating groove group is also radially spaced farther than the first dynamic pressure generating groove 131 and is opposite to the reverse Rayleigh step 18' of the fluid inlet groove 16. That is, all the second dynamic pressure generating grooves 132 constituting the second dynamic pressure generating groove group are only opposite to the reverse Rayleigh step 18'. In other words, only the reverse Rayleigh step 18' is located in the extension direction of all the second dynamic pressure generating grooves 132.

[0066] Thus, the shoulder portion 12d between the second dynamic pressure generating grooves 132 opposing the reverse Rayleigh step 18' is longer in the radial direction than the shoulder portion 12c between the reverse Rayleigh step 18, the fluid guide groove portion 17 and the first dynamic pressure generating groove 131 opposing them.

[0067] like Figure 3 As shown, the terminal ends 131a of the four first dynamic pressure generating grooves 131 of the dynamic pressure generating grooves 13 are arranged in a dense state close to the Rayleigh step 18 and the fluid guiding groove portion 17 via the shoulder portion 12c. In contrast, the terminal ends 132a of the three second dynamic pressure generating grooves 132 are arranged in a sparse state, separated from the reverse Rayleigh step 18' via the shoulder portion 12d.

[0068] In addition, the sparse state mentioned here refers to the following state: on the sliding surface 11, the proportion of the area where the dynamic pressure generating grooves 13 are arranged around the reverse Rayleigh step 18', especially the terminal 18a', is less than the proportion of the area where the dynamic pressure generating grooves 13 are arranged around the Rayleigh step 18, especially the terminal 18a. In addition, it can also be said that the total volume of the dynamic pressure generating grooves 13 arranged around the reverse Rayleigh step 18', especially the terminal 18a', that is, the second dynamic pressure generating grooves 132 is less than the total volume of the dynamic pressure generating grooves 13 arranged around the Rayleigh step 18, especially the terminal 18a, that is, the first dynamic pressure generating grooves 131. In this embodiment, compared with the second dynamic pressure generating grooves 132, which are all separated from the reverse Rayleigh step 18' by a longer distance in the radial direction, the first dynamic pressure generating grooves 131 are all separated from the Rayleigh step 18 by a shorter distance in the radial direction, that is, close. In addition, for the second dynamic pressure generating grooves 132 that are not arranged around the reverse Rayleigh step 18', especially the terminal 18a'. Figure 6In such a structure, it can be said that the dynamic pressure generating grooves 13 arranged around the reverse Rayleigh step 18', especially the terminal 18a', are sparser than the dynamic pressure generating grooves 13 arranged around the Rayleigh step 18, especially the terminal 18a, which will be described in detail later using other embodiments.

[0069] Next, use Figure 4 and Figure 5 The operation when the stationary seal ring 10 and the rotary seal ring 20 rotate relative to each other will be described. In this embodiment, the description will be made in the order of when the rotary seal ring 20 is stopped, when it rotates forward, and when it rotates reversely.

[0070] First, when the rotary seal ring 20 stops without rotating, the sealed fluid F flows into the fluid introduction groove 16. In addition, the stationary seal ring 10 is urged toward the rotary seal ring 20 by the elastic member 7, so that the sliding surfaces 11 and 21 are in contact with each other, and the amount of the sealed fluid F between the sliding surfaces 11 and 21 leaking to the external space S2 is almost zero.

[0071] like Figure 4 As shown, at a low speed just after the rotating seal ring 20 begins to rotate relative to the stationary seal ring 10 in the forward direction, the sealed fluid F in the Rayleigh step 18 follows the rotating seal ring 20 in the forward direction due to shearing with the sliding surface 21, thereby the sealed fluid F in the internal space S1 is sucked into the fluid guide groove 17.

[0072] That is, in the fluid introduction groove 16, the sealed fluid F moves from the fluid guide groove portion 17 toward the terminal 18a on the downstream side of the relative rotation direction in the Rayleigh step 18 as indicated by the arrow H1, and a force acts in the fluid guide groove portion 17 to suck in the sealed fluid F as indicated by the arrow H1. Figure 4 The flows of the sealed fluid F and the atmosphere A are schematically shown without specifying the relative rotation speed of the rotating seal ring 20 .

[0073] The sealed fluid F moving toward the terminal end 18a of the Rayleigh step 18 has its pressure increased at and in the vicinity of the terminal end 18a of the Rayleigh step 18. That is, a positive pressure is generated at and in the vicinity of the terminal end 18a of the Rayleigh step 18.

[0074] The Rayleigh step 18 is shallow, so even if the rotation speed of the rotary seal ring 20 is low and the amount of movement of the sealed fluid F is small, a positive pressure is generated at the terminal end 18 a of the Rayleigh step 18 and its vicinity.

[0075] In addition, the sliding surfaces 11 and 21 are slightly separated from each other by the force generated by the positive pressure generated at the terminal 18a of the Rayleigh step 18 and its vicinity. As a result, the sealed fluid F flows into the sliding surfaces 11 and 21 from the terminal 18a of the Rayleigh step 18 and the internal space S1 side. In this way, the sealed fluid F is interposed between the sliding surfaces 11 and 21, thereby improving the lubricity even at low speed rotation, and can suppress the wear of the sliding surfaces 11 and 21.

[0076] In addition, at a low speed just after the rotary seal ring 20 starts to rotate relative to the stationary seal ring 10 in the forward direction, the sealed fluid F in the reverse Rayleigh step 18' follows the rotary seal ring 20 in the forward direction due to shearing with the sliding surface 21, thereby generating a relative negative pressure at the terminal 18a' of the reverse Rayleigh step 18' and its vicinity. Therefore, as shown by arrow H2, a portion of the sealed fluid F that flows out from the terminal 18a of the Rayleigh step 18 to between the sliding surfaces 11 and 21 is sucked in and recovered from the terminal 18a' of the reverse Rayleigh step 18' on the downstream side adjacent to the shoulder portion 12b as shown by arrow H3. In addition, the sealed fluid F enters the fluid guide groove 17 from the reverse Rayleigh step 18', and a force acts in the fluid guide groove 17 to push a portion of the sealed fluid F toward the internal space S1.

[0077] On the other hand, in the dynamic pressure generating groove 13, when the relative rotation of the rotating seal ring 20 and the stationary seal ring 10 is low speed, the atmosphere A does not become sufficiently dense in the dynamic pressure generating groove 13, and a high positive pressure is not generated, and the force generated by the positive pressure generated by the dynamic pressure generating groove 13 is relatively smaller than the force generated by the positive pressure generated at the terminal 18a of the Rayleigh step 18 and its vicinity. Therefore, when the rotating seal ring 20 rotates at a low speed, the force generated by the positive pressure generated at the terminal 18a of the Rayleigh step 18 and its vicinity becomes the main force, and the sliding surfaces 11 and 21 are separated from each other.

[0078] When the relative rotation speed of the rotating seal ring 20 increases, as Figure 4 As shown, the atmosphere A in the dynamic pressure generating groove 13 moves in the positive rotation direction of the rotating seal ring 20 by shearing with the sliding surface 21, and the atmosphere A in the external space S2 is sucked into the dynamic pressure generating groove 13. That is, in the first dynamic pressure generating groove 131 and the second dynamic pressure generating groove 132, a large amount of atmosphere A moves from the starting ends 131b, 132b toward the terminal ends 131a, 132a as shown by the arrow L1, and a positive pressure is generated at the terminal ends 131a, 132a and their vicinities.

[0079] Thus, the force generated by the positive pressure generated at the terminal 18a of the Rayleigh step 18 and its vicinity is added to the force generated by the positive pressure generated at the terminal 131a, 132a of the dynamic pressure generating groove 13 and its vicinity, and the sliding surfaces 11 and 21 are further separated from each other than at a low speed. As a result, the atmosphere A in the dynamic pressure generating groove 13 mainly flows in between the sliding surfaces 11 and 21 as indicated by the arrow L2.

[0080] At this time, in the dynamic pressure generating groove 13, the atmosphere A mixed with the sealed fluid F as shown by the arrow L3 is pushed out from the terminals 131a, 132a and their vicinity toward the inner diameter side, i.e., the sealed fluid F side, by the atmosphere A as shown by the arrow L1 having a larger flow velocity and other energy.

[0081] The sliding components of this embodiment are designed so that when rotating at high speed in the forward direction, the positive pressure generating capacity of the dynamic pressure generating groove 13 as a whole is sufficiently large compared with the positive pressure generating capacity of the fluid inlet groove 16 as a whole. Therefore, a state is eventually formed in which only atmosphere A exists between the sliding surfaces 11 and 21, i.e., gas lubrication.

[0082] Thus, when the rotating seal ring 20 starts to rotate relative to the stationary seal ring 10 in the forward direction, the sliding surfaces 11 and 21 are lubricated by the sealed fluid F flowing from the fluid introduction groove 16 to between the sliding surfaces 11 and 21. When rotating at high speed, the sliding surfaces 11 and 21 are separated from each other by the positive pressure generated by the atmosphere A in the dynamic pressure generating groove 13, and the sealed fluid F and the atmosphere A are introduced between the sliding surfaces 11 and 21, so that the lubricity is improved, and the wear of the sliding surfaces 11 and 21 can be suppressed from the start of relative rotation to high-speed rotation. In addition, the dynamic pressure generating groove 13 extends to the inner space S1 side as the sealed fluid space, and the gas-liquid interface is located on the sealed fluid space side, so that the sealed fluid F is not easy to leak.

[0083] Next, use Figure 5 The reverse rotation of the rotary seal ring 20 will be described. Figure 5 As shown in FIG. 1 , when the rotary seal ring 20 rotates relative to the stationary seal ring 10 in the reverse direction, the sealed fluid F in the Rayleigh step 18 follows the rotary seal ring 20 in the reverse direction due to shearing with the sliding surface 21. As a result, the fluid guide groove 17 on the downstream side of the relative rotation direction is entered, and a force acts in the fluid guide groove 17 to push out a part of the sealed fluid F as shown by the arrow H1'. In addition, regarding Figure 5 The flows of the sealed fluid F and the atmosphere A are schematically shown without specifying the relative rotation speed of the rotating seal ring 20 .

[0084] On the other hand, the sealed fluid F in the reverse Rayleigh step 18' follows the rotation seal ring 20 in the reverse direction by shearing with the sliding surface 21, and generates positive pressure at its terminal 18a' and its vicinity. At this time, the second dynamic pressure generating groove 132 is separated from the reverse Rayleigh step 18' by a long distance in the radial direction, that is, the radial length of the shoulder 12d is long, so a relatively high positive pressure is generated at its terminal 18a' and its vicinity. As a result, between the sliding surfaces 11 and 21, the sealed fluid F flows in from the terminal 18a' (refer to arrow H3') of the reverse Rayleigh step 18' and the internal space S1 side.

[0085] Thus, when the rotating seal ring 20 is reversed counterclockwise relative to the stationary seal ring 10, the sealed fluid F sucked into the fluid introduction groove 16 is supplied from the terminal 18a' of the reverse Rayleigh step 18' to between the sliding surfaces 11 and 21, thereby preventing poor lubrication. In addition, the fluid guide groove 17 is provided, so that a large amount of the sealed fluid F can be retained.

[0086] In addition, since the shoulder 12 b extends in the circumferential direction between the reverse Rayleigh step 18 ′ and the adjacent downstream Rayleigh step 18 , the sealed fluid flowing out in the circumferential direction from the reverse Rayleigh step 18 ′ easily flows to the downstream Rayleigh step 18 .

[0087] As described above, when the rotary seal ring 20 is reversed, most of the sealed fluid F supplied from the terminal 18a' of the reverse Rayleigh step 18' to the sliding surfaces 11 and 21 is supplied to the shoulder portion 12b and the shoulder portion 12d between the adjacent fluid introduction grooves 16. At the shoulder portion 12d, the radial distance from the second dynamic pressure generating groove 132 is greater than that of the shoulder portion 12c, that is, the second dynamic pressure generating groove 132 is arranged in a sparse state relative to the reverse Rayleigh step 18', compared with the first dynamic pressure generating groove 131 being in a dense state relative to the Rayleigh step 18. Therefore, it is possible to suppress the sealed fluid F from immediately flowing to the second dynamic pressure generating groove 132, and it is easy to generate a relatively high positive pressure at the terminal 18a' of the reverse Rayleigh step 18' and its vicinity, that is, the shoulder portion 12b and the shoulder portion 12d, so that a gap sufficient for the sealed fluid F to flow in can be formed between the sliding surfaces 11 and 21, and the sliding surfaces 11 and 21 can be fully lubricated with each other.

[0088] In addition, in particular, compared with the terminal 131a of the first dynamic pressure generating groove 131 being in a tight state relative to the terminal 18a of the Rayleigh step 18, the terminal 132a of the second dynamic pressure generating groove 132 is arranged in a sparse state relative to the terminal 18a' of the reverse Rayleigh step 18'. Therefore, when positive pressure is generated at the reverse Rayleigh step 18' during reversal, the influence of the negative pressure generated on the terminal 132a side of the second dynamic pressure generating groove 132 is less, and therefore pressure is easily generated at the terminal 18a' of the reverse Rayleigh step 18' and its vicinity, that is, the shoulder portion 12b and the shoulder portion 12d.

[0089] In addition, there are multiple shoulder portions 12b and 12d, i.e., areas where the reverse Rayleigh step 18' and the second dynamic pressure generating groove 132 become sparse, arranged in the circumferential direction of the sliding surface 11. Therefore, during reversal, pressure is easily generated at the terminal end 18a' of the reverse Rayleigh step 18' at multiple locations along the entire circumference of the sliding surface 11, thereby enabling the sliding surfaces 11 and 21 to be fully lubricated with each other.

[0090] In addition, a Rayleigh step 18 is arranged on the reversing direction side of the reverse Rayleigh step 18', so that a portion of the sealed fluid F that flows into the sliding surfaces 11 and 21 from the terminal 18a' of the reverse Rayleigh step 18' as shown by the arrow H3' is sucked in and recovered from the terminal 18a of the Rayleigh step 18 on the downstream side adjacent to the shoulder portion 12b as shown by the arrow H2', and is not easily leaked to the external space S2 serving as the leakage space.

[0091] In addition, the Rayleigh step 18 and the reverse Rayleigh step 18' are roughly T-shaped and share the common fluid guide groove 17. Therefore, in either the forward rotation or the reverse rotation, in addition to the sealed fluid F in the fluid guide groove 17, the sealed fluid F in the Rayleigh step on the other side when positive pressure is generated on one side can also be utilized, so that a sufficient amount of sealed fluid F can be used to efficiently generate positive pressure.

[0092] In addition, the first dynamic pressure generating groove 131 and the second dynamic pressure generating groove 132 are spiral grooves extending in an arc shape from the starting ends 131b and 132b toward the inner diameter side, so that positive pressure can be efficiently generated at the terminal ends 131a and 132a using the fluid on the side of the external space S2 serving as the leakage space, which is gas here.

[0093] In addition, the positive fluid inlet and outlet groove is composed of the following parts: a fluid guide groove portion 17, which is connected to the internal space S1; and a Rayleigh step 18 as a dynamic pressure generating portion, which extends circumferentially from the outer diameter side of the fluid guide groove portion 17 toward the forward rotation direction of the rotating seal ring 20 and concentrically with the stationary seal ring 10. The reverse fluid inlet and outlet groove is composed of the following parts: a fluid guide groove portion 17, which is connected to the internal space S1; and a reverse Rayleigh step 18' as a dynamic pressure generating portion, which extends circumferentially from the outer diameter side of the fluid guide groove portion 17 toward the reverse rotation direction of the rotating seal ring 20 and concentrically with the stationary seal ring 10. Furthermore, the Rayleigh step 18 and the reverse Rayleigh step 18' extend in the relative forward rotation direction or the relative reverse rotation direction. Therefore, during forward rotation and reverse rotation, most of the sealed fluid F flows out from the terminal end 18a of the Rayleigh step 18 or the terminal end 18a' of the reverse Rayleigh step 18' toward the circumferential direction, that is, toward the shoulder portion 12b, and is therefore not easily sucked in from the terminal end 132a of the second dynamic pressure generating groove 132.

[0094] [Example 2]

[0095] Next, refer to Figure 6 The sliding member of Example 2 will be described. In addition, the same structure as that of the above-mentioned Example 1 and the repeated description will be omitted.

[0096] In the above-mentioned embodiment 1, the following structure is described: by shortening the radial length of the second dynamic pressure generating groove 132 compared with the first dynamic pressure generating groove 131, the dynamic pressure generating groove 13 is in a tight state relative to the Rayleigh step 18, and in comparison, it is in a sparse state relative to the reverse Rayleigh step 18', but in the sliding component of the present embodiment 2, the dynamic pressure generating groove opposite to the reverse Rayleigh step 18' in the extension direction is omitted, that is, in the dynamic pressure generating groove 13 of the present embodiment 2, there is no dynamic pressure generating groove extending toward the shoulder portion 12d in its extension direction, and the dynamic pressure generating groove 13 is in a sparse state relative to the reverse Rayleigh step 18'.

[0097] Thus, the positive pressure generating capability of the entire dynamic pressure generating groove 13 during normal rotation is slightly reduced, but leakage of the sealed fluid F from the dynamic pressure generating groove opposing the reverse Rayleigh step 18 ′ in the extension direction can be further suppressed.

[0098] [Example 3]

[0099] Next, refer to Figure 7 The sliding member of Example 3 will be described. In addition, the same structure as that of the above-mentioned Example 1 and the repeated description will be omitted.

[0100] In the above-mentioned embodiment 1, the following structure is described: by shortening the radial length of the second dynamic pressure generating groove 132 compared with the first dynamic pressure generating groove 131, the dynamic pressure generating groove 13 is in a dense state relative to the Rayleigh step 18, and in comparison, it is in a sparse state relative to the reverse Rayleigh step 18'. However, in the sliding component of the present embodiment 3, the radial lengths of the first dynamic pressure generating groove 131 and the second dynamic pressure generating groove 232 are the same, and the number of the second dynamic pressure generating grooves 232 opposite to the reverse Rayleigh step 18' in the extension direction is smaller than the number of the first dynamic pressure generating grooves 131 opposite to the Rayleigh step 18 in the extension direction, thereby, the dynamic pressure generating groove 13 is in a sparse state relative to the reverse Rayleigh step 18'.

[0101] Therefore, during reversal, the sealed fluid F is easily partially sucked in from the second dynamic pressure generating groove 232 opposite to the reverse Rayleigh step 18' in the extension direction, but the second dynamic pressure generating groove 232 extends to the side of the internal space S1 which is the sealed fluid space. Therefore, during forward rotation, the gas-liquid interface is located on the side of the sealed fluid space, so that the sealed fluid F is not easy to leak.

[0102] [Example 4]

[0103] Next, refer to Figure 8 The sliding member of Example 4 will be described. In addition, the same structure as that of the above-mentioned Example 1 and the repeated description will be omitted.

[0104] In the above-mentioned embodiment 1, the Rayleigh step 18 and the reverse Rayleigh step 18' are formed integrally as the roughly T-shaped fluid inlet groove 16 of the common fluid guide groove portion 17, but in the sliding component of the present embodiment 4, the Rayleigh step 18 and the fluid guide groove portion 17 constitute the forward fluid inlet and outlet groove 26, and the reverse Rayleigh step 18' and the fluid guide groove portion 17' constitute the reverse fluid inlet and outlet groove 26', which are arranged to separate the fluid guide groove portions 17 and 17' from each other in the circumferential direction.

[0105] Thus, the forward fluid inlet and outlet grooves 26 and the reverse fluid inlet and outlet grooves 26' can be cut, so that in either forward or reverse rotation, the movement of the sealed fluid F on one side is unlikely to affect the other side, making it easy to design for obtaining the required positive pressures.

[0106] [Example 5]

[0107] Next, refer to Fig. 9 The sliding member of Example 5 will be described. In addition, the same structure as that of the above-mentioned Example 1 and the repeated description will be omitted.

[0108] The dynamic pressure generating groove 23 is open to the leakage space and communicates with it, and is inclined toward the downstream side of the sealed fluid space side, and is set to the terminal 23a in a straight line. The radial position of each terminal 23a of the plurality of parallel dynamic pressure generating grooves 23 gradually changes along the circumferential direction, and is arranged on a smooth and continuous virtual curve in a sine wave shape in the entire circumferential direction. In addition, it is not limited to this embodiment. Although not specifically shown in the figure, the virtual curve configuring the terminal 23a may not have periodicity like the sine wave shape.

[0109] The dynamic pressure generating grooves 23A to 23L of the dynamic pressure generating grooves 23 are formed into one dynamic pressure generating groove group. The dynamic pressure generating groove groups are evenly arranged in the circumferential direction, and one fluid introduction groove 16 is arranged for each dynamic pressure generating groove group.

[0110] like Fig. 9 As shown, the reverse Rayleigh step 18' is located in the extension direction of the dynamic pressure generating groove 23L at the terminal 23a closest to the leakage space side (here, the outer diameter side), and the shoulder portion 12d is located in the extension direction of the dynamic pressure generating groove 23A at the terminal 23a closer to the sealed fluid space side (here, the inner diameter side) than the dynamic pressure generating groove 23L. In addition, the Rayleigh step 18 is located across the shoulder portion 12c in the extension direction of the dynamic pressure generating grooves 23F to 23H at the terminal 23a located on the sealed fluid space side (here, the inner diameter side). In this way, the terminal 23a of the dynamic pressure generating groove 23 is arranged in a close state with respect to the Rayleigh step 18 and the fluid guide groove portion 17 across the shoulder portion 12c, while, on the reverse Rayleigh step 18' side, the terminal 23a is separated and arranged in a sparse state across the shoulder portion 12d.

[0111] Thus, the plurality of terminals 23a are arranged on a virtual curve of a sine wave shape, so that when the rotary seal ring 20 rotates forward, positive pressure is generated at different radial positions along the circumferential direction on the sliding surface 211, and the radial pressure gradient on the sliding surface 211 becomes small, so that it is easy to uniformly form a fluid film on a large area of ​​the sliding surface 211. Therefore, the lubricity between the sliding surfaces 211 and 21 is good. In addition, when the rotation is reversed, the terminal 23a of the dynamic pressure generating groove 23 is separated from the reverse Rayleigh step 18' and becomes sparse, so it is easy to generate pressure at the shoulder portion 12d.

[0112] Furthermore, in the fifth embodiment, the reverse Rayleigh step 18' is located in the extension direction of the dynamic pressure generating groove 23L at the terminal 23a which is closest to the sealed fluid space side (here, the outer diameter side), and the Rayleigh step 18 is located in the extension direction of the dynamic pressure generating grooves 23F to 23H at the terminal 23a which is relatively close to the leakage space side (here, the inner diameter side), but this is not limited to this, and the Rayleigh step 18 or the reverse Rayleigh step 18' may also be located in the extension direction of any of the dynamic pressure generating grooves 23A to 23L as long as it is arranged in a dense state relative to the Rayleigh step 18 and, in contrast, in a sparse state relative to the reverse Rayleigh step 18'.

[0113] [Example 6]

[0114] Next, refer to Fig.10 The sliding member of Example 6 will be described. In addition, the same structure as that of the above-mentioned Example 1 and the repeated description will be omitted.

[0115] In the sliding member of the sixth embodiment, the radial lengths of the first dynamic pressure generating groove 131 and the second dynamic pressure generating groove 133 are the same, and the groove width of the second dynamic pressure generating groove 133 opposite to the reverse Rayleigh step 18' in the extension direction is shorter than that of the first dynamic pressure generating groove 131 opposite to the Rayleigh step 18 in the extension direction. In this way, the dynamic pressure generating groove 13 is sparsely spaced relative to the reverse Rayleigh step 18'.

[0116] Thus, during reverse rotation, the sealed fluid F is partially sucked from the second dynamic pressure generating groove 133 opposite to the reverse Rayleigh step 18' in the extension direction, but the amount sucked is small. In addition, the second dynamic pressure generating groove 133 extends to the inner space S1 side as the sealed fluid space, so that during normal rotation, the gas-liquid interface is located on the sealed fluid space side, so that the sealed fluid F is not easy to leak.

[0117] [Example 7]

[0118] Next, refer to Fig.11 The sliding member of Example 7 will be described. In addition, the same structure as that of the above-mentioned Example 1 and the repeated description will be omitted.

[0119] In the sliding member of the present embodiment 7, the radial lengths of the first dynamic pressure generating groove 131 and the second dynamic pressure generating groove 134 are the same, and the depth dimension of the second dynamic pressure generating groove 134 opposite to the reverse Rayleigh step 18' in the extension direction is shorter than that of the first dynamic pressure generating groove 131 opposite to the Rayleigh step 18 in the extension direction. In this way, the dynamic pressure generating groove 13 is sparsely spaced relative to the reverse Rayleigh step 18'.

[0120] Thus, during reverse rotation, the sealed fluid F is partially sucked from the second dynamic pressure generating groove 134 that is opposite to the reverse Rayleigh step 18' in the extension direction, but the absolute value of the negative pressure generated by the second dynamic pressure generating groove 134 at a predetermined rotation speed is smaller than that of the first dynamic pressure generating groove 131, so the influence on the positive pressure generated at the terminal 18' and the vicinity of the reverse Rayleigh step 18' is small. In addition, the second dynamic pressure generating groove 134 extends to the inner space S1 side as the sealed fluid space, so that during forward rotation, the gas-liquid interface is located on the sealed fluid space side, so that the sealed fluid F is difficult to leak.

[0121] As mentioned above, although the embodiment of the present invention is described based on the drawings, the specific structure is not limited to these embodiments, and even if there are changes and additions within the scope that does not depart from the gist of the present invention, they are also included in the present invention.

[0122] For example, in the above-mentioned embodiments 1 to 7, the sliding parts are described by taking the mechanical seal for automobile as an example, but other mechanical seals for general industrial machinery etc. may also be used. In addition, it is not limited to mechanical seals, and may be sliding parts other than mechanical seals such as sliding bearings.

[0123] Furthermore, in the above-mentioned first to seventh embodiments, the examples in which the dynamic pressure generating groove and the fluid introducing groove are provided in the stationary seal ring are described. However, the dynamic pressure generating groove and the fluid introducing groove may be provided in the rotating seal ring.

[0124] In addition, in the above-mentioned embodiments 1 to 7, the sealed fluid side is described as the high-pressure side and the leakage side is described as the low-pressure side, but the sealed fluid side may be the low-pressure side and the leakage side may be the high-pressure side, or the sealed fluid side and the leakage side may be at approximately the same pressure.

[0125] In addition, the mechanical seals with sliding parts in the above-mentioned embodiments 1 to 7 are described as an outer type, but can also be applied to an inner type in which a fluid leaking from the outer periphery of the sliding surface to the inner periphery is sealed. In the case of the inner type, for example, Fig.12 As shown in the sliding part 30, the first dynamic pressure generating groove 331 and the second dynamic pressure generating groove 332 as the dynamic pressure generating groove 33 are arranged on the inner diameter side, that is, the inner space S11 side as the leakage space, and the fluid introduction groove 36 having the Rayleigh step 38, the reverse Rayleigh step 38' and the fluid guide groove portion 37 is arranged on the outer diameter side, that is, the outer space S12 side as the sealed fluid space.

[0126] Furthermore, in the above-mentioned Embodiments 1 to 7, the case where the dynamic pressure generating groove and the leakage space are communicated is described, but the present invention is not limited to this, and the dynamic pressure generating groove and the leakage space do not need to be communicated as long as dynamic pressure can be generated.

[0127] In the above-mentioned embodiments 1 to 7, the fluid introduction groove is described as being in communication with the sealed fluid space, but the present invention is not limited thereto and may not be in communication as long as the sealed fluid can be stored, and may be, for example, a recess.

[0128] In addition, in the above-mentioned embodiments 1 to 7, the fluid introduction groove has a Rayleigh step, but it is not limited to this. As long as positive pressure can be generated during forward rotation and reverse rotation, for example, the Rayleigh step part can also be an inclined groove that is inclined in the circumferential direction and extends in the radial direction.

[0129] Furthermore, in the above-mentioned Examples 1 to 7, an example is given in which a plurality of fluid introduction grooves are provided in the circumferential direction, but it is sufficient that at least one is provided.

[0130] In the above-mentioned embodiments 1 to 7, the sealed fluid is described as a high-pressure liquid, but it is not limited thereto and may be a gas or a low-pressure liquid, or may be a mist formed by a mixture of liquid and gas.

[0131] In the above-mentioned embodiments 1 to 7, the fluid on the leakage side is described as low-pressure gas, that is, atmospheric air. However, the present invention is not limited thereto and may be liquid or high-pressure gas, or may be a mist formed by a mixture of liquid and gas.

[0132] Explanation of symbols

[0133] 10: stationary seal ring; 11, 21: sliding surface; 12a~12d: shoulder; 13: dynamic pressure generating groove (positive dynamic pressure generating groove); 16: fluid introduction groove; 17: fluid guide groove (positive fluid introduction and derivation groove, reverse fluid introduction and derivation groove); 18: Rayleigh step (positive fluid introduction and derivation groove); 18': reverse Rayleigh step (reverse fluid introduction and derivation groove); 18a, 18a': terminal; 20: rotating seal ring; 23: dynamic pressure generating groove; 23A~23L: dynamic pressure generating groove; 23a : terminal; 26: reverse fluid inlet and outlet groove; 26: forward fluid inlet and outlet groove; 131: first dynamic pressure generating groove; 131a: terminal; 131: second dynamic pressure generating groove; 132a: terminal; 133: second dynamic pressure generating groove; 134: second dynamic pressure generating groove; 232: second dynamic pressure generating groove; F: sealed fluid; S1: internal space (sealed fluid space); S2: external space (leakage space); S11: internal space (leakage space); S12: external space (sealed fluid space).

Claims

1. A sliding component, wherein the sliding surfaces of a pair of sliding rings rotate relative to each other and divide the sealed fluid space and the leakage space, wherein: On at least one of the sliding surfaces, there is provided: a positive dynamic pressure generating groove, which is connected to the leakage space; a positive fluid introduction and outlet groove, which is separated from the positive dynamic pressure generating groove by a shoulder portion and is connected to the sealed fluid space; and a reverse fluid introduction and outlet groove, which is separated from the positive dynamic pressure generating groove by a shoulder portion and communicates with the sealed fluid space, The positive direction dynamic pressure generating grooves are arranged more sparsely with respect to the negative direction fluid introduction and discharge grooves than with respect to the positive direction fluid introduction and discharge grooves.

2. The sliding component according to claim 1, wherein: The terminal ends of the forward direction dynamic pressure generating grooves are arranged more sparsely with respect to the terminal ends of the reverse direction fluid introduction and outlet grooves than with respect to the terminal ends of the forward direction fluid introduction and outlet grooves.

3. The sliding component according to claim 1, wherein: The rarefaction state is achieved by arranging the forward dynamic pressure generating grooves having a smaller total volume relative to the reverse fluid introduction and discharge grooves than relative to the forward fluid introduction and discharge grooves.

4. The sliding component according to claim 1, wherein: The rarefaction state is achieved by arranging the positive direction dynamic pressure generating grooves shorter in the radial direction with respect to the negative direction fluid introduction and discharge grooves than with respect to the positive direction fluid introduction and discharge grooves.

5. The sliding component according to claim 1, wherein: A plurality of regions in the sparse state are arranged in the circumferential direction of the sliding surface.

6. The sliding component according to any one of claims 1 to 5, wherein: The positive dynamic pressure generating groove is a spiral groove extending in an arc shape from the starting end at an inclination relative to the radial direction. The positive fluid inlet and outlet groove has a fluid guide groove portion connected to the sealed fluid space and a Rayleigh step extending along the relative positive rotation direction. The reverse fluid inlet and outlet groove has a fluid guide groove portion connected to the sealed fluid space and a reverse Rayleigh step extending along the relative reverse direction.

7. The sliding component according to claim 6, wherein: The forward fluid introduction and outlet groove and the reverse fluid introduction and outlet groove are substantially T-shaped and share the fluid guide groove portion.

8. The sliding component according to any one of claims 1 to 5, wherein: The forward fluid introduction and discharge groove is arranged on the reverse direction side of the reverse fluid introduction and discharge groove.

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