sliding element

Abstract

A sliding element is provided that can prevent the sealed fluid from leaking into the space on the leakage side, regardless of the relative rotation direction, forward or reverse rotation. A pair of sliding members (10, 20) are provided such that sliding surfaces (11, 21) rotate relative to each other and slide. The sliding surface (11) has a plurality of low-speed rotation inlet grooves (13, 13') in communication with a space (S2) on the side of the fluid to be sealed (F), and the sliding surface (11) has a high-speed rotation dynamic pressure generating groove (12) in communication with a space (S1) on the side of leakage. In the sliding surface (11) having the low-speed rotation inlet grooves (13, 13'), groove means (14, 15') are additionally provided, which are positioned on the side of the fluid to be sealed (F) rather than the dynamic pressure generating groove (12) and allow the fluid to be sealed (F) to flow between adjacent inlet grooves (13, 13').

Description

Technology Field

[0001] The present invention relates to a sliding element having a pair of sliding members used in a sliding element, for example, a shaft seal or a bearing. Background Technology

[0002] In rotating machinery, mechanical seals are known as sliding elements that prevent leakage of a sealed fluid around a rotating shaft, for example, by sliding the sliding surfaces of a pair of sliding members relative to each other. In such mechanical seals, there is a recent demand for a reduction in energy lost due to sliding for reasons such as environmental measures, and there are types in which a dynamic pressure generating groove is provided on the sliding surface to separate the sliding surfaces.

[0003] For example, the mechanical seal described in Patent Document 1 has a plurality of spiral grooves provided on the sliding surface of one sliding member, each serving as an inlet groove communicating with the fluid to be sealed and a dynamic pressure generating groove communicating with the leakage side. The inlet groove extends in the inner diameter direction while inclined in the circumferential direction from the fluid to be sealed side. Additionally, the spiral groove extends in the outer diameter direction while inclined in the circumferential direction from the leakage side.

[0004] When the relative rotational speed of the sliding member is low, the introduction groove introduces the fluid to be sealed between the sliding surfaces. Consequently, since a liquid film is formed between the sliding surfaces, the introduction groove can contribute to improving lubricity between a pair of sliding surfaces. Additionally, the spiral groove draws in a small amount of gas from the leakage side. Since this gas prevents the fluid to be sealed from moving toward the leakage side, the spiral groove can contribute to preventing leakage of the fluid to be sealed toward the leakage side.

[0005] Meanwhile, when the relative rotational speed of the sliding member is high, static pressure is generated at the closed end located on the outer diameter side of the sliding surface in the spiral groove that draws in gas from the leakage side. Since this static pressure causes a slight separation between the sliding surfaces, the spiral groove can contribute to improving lubricity between a pair of sliding surfaces. Furthermore, similar to the case where the relative rotational speed of the sliding member is low, the spiral groove that draws in gas between the sliding surfaces can contribute to preventing leakage of the sealed fluid to the leakage side. Prior art literature

[0006] International Publication No. 2018 / 051867 (Page 10, Fig. 3) The problem to be solved

[0007] However, depending on the type of rotating machine, the direction of rotation may be changed according to the situation. Therefore, there is a demand for a mechanical seal that can handle not only forward rotation but also reverse rotation of the relative rotation between sliding members. However, in a mechanical seal such as that of Patent Document 1, when the relative rotation of the sliding members is reverse rotation, the fluid to be sealed is supplied from the introduction groove between the sliding surfaces to ensure lubrication, but there was a risk that the fluid to be sealed supplied between the sliding surfaces would flow into the spiral groove and leak into the leakage side space.

[0008] The present invention was made by focusing on these problems and aims to provide a sliding element capable of preventing the sealed fluid from leaking into the space on the leakage side, regardless of the relative rotation direction of forward or reverse rotation. means of solving the problem

[0009] To solve the above problem, the sliding element of the present invention is,

[0010] A pair of sliding members are provided, wherein the sliding surfaces rotate relative to each other and slide.

[0011] At least one of the above sliding surfaces has a plurality of low-speed rotation introduction grooves communicating with the space on the fluid-to-seal side, and

[0012] At least one of the above sliding surfaces is a sliding element having a dynamic pressure generating groove for high-speed rotation that communicates with the space on the leakage side,

[0013] On the sliding surface having the above-mentioned introduction groove for low-speed rotation, a groove means is additionally provided that is positioned on the fluid to be sealed side rather than the dynamic pressure generating groove and enables the fluid to be sealed to flow between adjacent introduction grooves.

[0014] According to this, when the relative rotation is forward rotation and also low speed, the introduction groove introduces the fluid to be sealed between the sliding surfaces. Accordingly, the lubricity of the pair of sliding surfaces is improved. Furthermore, when the relative rotation is forward rotation and also high speed, the dynamic pressure generating groove introduces the fluid on the leakage side between the sliding surfaces. Accordingly, the lubricity of the pair of sliding surfaces is improved. On the other hand, when the relative rotation is reverse rotation, the introduction groove introduces the fluid to be sealed between the sliding surfaces. Accordingly, the lubricity of the pair of sliding surfaces is improved. In addition, the groove means can efficiently introduce the fluid to be sealed that has entered into one introduction groove into an adjacent introduction groove. That is, the fluid to be sealed is recovered into the introduction groove through the groove means. In this way, the groove means can contribute to preventing leakage of the fluid to be sealed into the space on the leakage side through the dynamic pressure generating groove.

[0015] The above groove means may be a first groove extending from the introduction groove and a second groove extending from the introduction groove in a direction opposite to that of the first groove.

[0016] According to this, static pressure is generated in the first groove or the second groove depending on the direction of rotation. Accordingly, the first groove or the second groove can contribute to improving lubricity on a pair of sliding surfaces.

[0017] The first groove and the second groove may be extended in an arc shape.

[0018] According to this, in the first and second grooves formed in an arc shape, it is difficult to generate dynamic pressure, such as positive or negative pressure in the radial direction. For this reason, the first and second grooves are designed to facilitate the flow of a sealed fluid from one inlet groove to an adjacent inlet groove.

[0019] The end portion in the first groove of one of the above-mentioned introduction grooves may be positioned on the leakage side rather than the end portion in the second groove of the adjacent introduction groove.

[0020] According to this, when the relative rotation is reverse rotation, the first groove can efficiently recover the sealed fluid leaked from the second groove.

[0021] The first groove of one of the above-mentioned introduction grooves may be arranged to partially overlap in the diameter direction with the second groove of the adjacent introduction groove.

[0022] According to this, when the relative rotation is reverse rotation, the first groove can recover the sealed fluid leaked from the second groove more efficiently.

[0023] The above-mentioned inlet groove, the above-mentioned first groove, and the above-mentioned second groove may have the same depth.

[0024] According to this, the flow of the fluid to be sealed in the introduction groove, the first groove, and the second groove is made smooth, whether the relative rotation is forward rotation or reverse rotation.

[0025] One of the above sliding members has an introduction groove for low-speed rotation, a dynamic pressure generating groove for high-speed rotation, and a groove means.

[0026] According to this, since the positions of the introduction groove for low-speed rotation, the dynamic pressure generating groove for high-speed rotation, and the groove means do not change even during relative rotation, the fluid to be sealed can be smoothly introduced into the adjacent introduction groove. Brief explanation of the drawing

[0027] FIG. 1 is a cross-sectional view showing an example of a mechanical seal in Example 1 of the present invention. FIG. 2 is a view of the sliding surface of the rotary seal ring in Example 1 from the axial direction. FIG. 3 is an enlarged view from the axial direction of the sliding surface of the rotation seal ring in the case where the relative rotation is forward rotation and also low speed in Example 1. FIG. 4 is an enlarged view from the axial direction of the sliding surface of the rotation seal ring in the case where the relative rotation is also a forward rotation and high speed in Example 1. FIG. 5 is an enlarged view of the sliding surface of the rotation seal ring in the case where the relative rotation is reverse rotation in Example 1, viewed from the axial direction. FIG. 6 is a view of the sliding surface of the rotary sealing ring in Example 2 of the present invention seen from the axial direction. FIG. 7 is a view of the sliding surface of the rotary sealing ring in Example 3 of the present invention seen from the axial direction. FIG. 8 is a view of the sliding surface of the rotary sealing ring in Example 4 of the present invention seen from the axial direction. FIG. 9 is a view of the sliding surface of the rotary sealing ring in Example 5 of the present invention seen from the axial direction. FIG. 10 is a view of the sliding surface of the rotary sealing ring in Example 6 of the present invention seen from the axial direction. FIG. 11 is a view of the sliding surface of the rotary sealing ring in Example 7 of the present invention seen from the axial direction. FIG. 12 is a view of the sliding surface of the rotary sealing ring in Example 8 of the present invention seen from the axial direction. Specific details for implementing the invention

[0028] A form for implementing a sliding element according to the present invention is described below based on an example.

[0029] Example 1

[0030] A sliding element according to Example 1 will be described with reference to FIGS. 1 to 5. In addition, in this embodiment, a mechanical seal having a pair of rotating sealing rings and a static sealing ring is described as an example of a sliding element having a pair of sliding members. Also, for convenience of explanation, dots may be provided in the drawings, such as in the grooves formed on the sliding surface.

[0031] As shown in FIG. 1, the mechanical seal (M) of the present embodiment is a so-called inside-type mechanical seal that prevents the fluid to be sealed (F) existing in the outer space (S2) from leaking into the inner space (S1) where the atmosphere (A) exists.

[0032] In this embodiment, the fluid to be sealed (F) is a high-pressure liquid. Also, the atmosphere (A) is a gas with a lower pressure than the fluid to be sealed (F). That is, the inner diameter side of the sealing ring constituting the mechanical seal (M) is the leakage side (low-pressure side). Also, the outer diameter side is the fluid to be sealed side (high-pressure side). Furthermore, in the present invention, it is preferable to have a combination such that there is no problem even if the fluid on the leakage side is mixed with the fluid to be sealed.

[0033] The mechanical seal (M) is mainly composed of a rotating seal ring (10) and a stationary seal ring (20). The rotating seal ring (10) is circular in shape and is provided to be rotatable together with the rotating shaft (1) through a sleeve (2) on the rotating shaft (1).

[0034] The stop seal ring (20) is formed in an annular shape and is provided in a non-rotating state and axially movable state on a seal cover (5) fixed to a housing (4) in a device to be mounted.

[0035] The stationary sealing ring (20) is axially supported by an elastic member (7). Accordingly, the sliding surface (11) of the rotating sealing ring (10) and the sliding surface (21) of the stationary sealing ring (20) are configured to slide closely together. In addition, the sliding surface (21) of the stationary sealing ring (20) is formed as a flat surface, and no grooves, etc., are provided on this flat surface.

[0036] The rotating seal ring (10) and the stationary seal ring (20) are typically formed from SiC (hard material) or a combination of SiC (hard material) and carbon (soft material), but are not limited thereto; any sliding material used as a sliding material for a mechanical seal can be applied. Furthermore, as SiC, materials consisting of two or more phases with different components and compositions, such as sintered bodies made of boron, aluminum, carbon, etc. as sintering aids, are used, for example, SiC with dispersed graphite particles, reaction-sintered SiC consisting of SiC and Si, SiC-TiC, SiC-TiN, etc. As for carbon, materials such as carbon mixed with carbonaceous and graphite materials, resin-molded carbon, and sintered carbon can be used. In addition, other than the above sliding materials, metal materials, resin materials, surface modification materials (coating materials), composite materials, etc. can also be applied.

[0037] As shown in FIG. 2, the rotating sealing ring (10) is configured to slide relative to the stationary sealing ring (20) in a counterclockwise direction, as indicated by the solid arrow, or in a clockwise direction, as indicated by the dashed arrow. Hereinafter, the direction of the solid arrow is described as the forward rotation direction of the rotating sealing ring (10), which is the relative sealing ring, and the direction of the dashed arrow is described as the reverse rotation direction.

[0038] The sliding surface (11) in the rotary sealing ring (10) is composed of a plurality of spiral grooves (12) as dynamic pressure generating grooves, a plurality of introduction grooves (13), a plurality of first grooves (14) that are part of the groove means, a plurality of second grooves (15) that are part of the groove means, and a land (16).

[0039] Afterwards, since multiple spiral grooves (12) have the same shape, if it is not necessary, an explanation is given for one spiral groove (12). This is also the case for the introduction groove (13), the first groove (14), and the second groove (15).

[0040] Additionally, regarding the inlet groove (13), for convenience of explanation, the groove shown on the left side of the paper surface in FIG. 3 may be described as one inlet groove (13), and the groove shown on the right side of the same paper surface as one inlet groove (13), in other words, the groove arranged adjacent to one inlet groove (13) in a clockwise direction as another inlet groove (13'). Additionally, there may be cases where it is described as another first groove (14') and another second groove (15') that are in communication with the other inlet groove (13').

[0041] As shown in FIGS. 2 and 3, the spiral groove (12) extends in an arc shape while inclined with a reverse rotational component from the opening end (12A) toward the outer diameter side. Additionally, the spiral groove (12) is equally distributed on the inner diameter side of the sliding surface (11).

[0042] The inner diameter side of the spiral groove (12) is formed as an open end (12A) communicating with the inner space (S1). The outer diameter side of the spiral groove (12) is formed as a closed end (12B). The depth of the spiral groove (12) is formed to be constant in the elongation direction.

[0043] The introduction groove (13) extends in a parallelogram shape, inclined in the reverse rotation direction toward the inner diameter side from the opening end (13A). Additionally, the introduction groove (13) is equal in diameter on the outer diameter side of the sliding surface (11).

[0044] The opening end (13A) on the outer diameter side of the introduction groove (13) is in communication with the outer space (S2). The inner diameter side of the introduction groove (13) is formed by an inner diameter side wall (13B). The reverse rotation direction side of the introduction groove (13) is formed by a reverse rotation side wall (13C). The forward rotation direction side of the introduction groove (13) is formed by a forward rotation side wall (13D). The depth of the introduction groove (13) is formed to be constant in the elongation direction.

[0045] The reverse rotation side wall (13C) extends in a reverse rotation direction, inclined from the outer diameter side toward the inner diameter side. Additionally, the forward rotation side wall (13D) is positioned opposite the reverse rotation side wall (13C) and extends approximately parallel to it.

[0046] The first groove (14) is an arc-shaped groove extending in the reverse rotational direction in a concentric shape with the rotational sealing ring (10) from the opening end (14A). Additionally, the first groove (14) is symmetrically positioned at the outer diameter side of the spiral groove (12) and also at the radial center of the sliding surface (11).

[0047] In the first groove (14), the forward rotation direction side is formed as an open end (14A) that communicates with the inner diameter side end of the reverse rotation side wall (13C) in the introduction groove (13). Additionally, the inner diameter side wall in the first groove (14) is continuous with the inner diameter side wall (13B) in the introduction groove (13). In other words, the first groove (14) is formed to allow the fluid to be sealed (F) to flow between the outer space (S2) and the outer space (S2) at the position furthest from the outer space (S2) among the grooves (13, 14, 15) that communicate with the outer space (S2). The reverse rotation direction side in the first groove (14) is formed as a closed end (14B). The depth of the first groove (14) is formed to be constant in the elongation direction.

[0048] In addition, since the introduction groove (13) and the first groove (14) are continuous, in FIGS. 3 to 6, for convenience of explanation, the opening end (14A) in the first groove (14) is shown with a dotted line. This is also the same for the opening end (15A) in the second groove (15).

[0049] The second groove (15) is an arc-shaped groove that extends from the opening end (15A) in a concentric shape with the rotational sealing ring (10) in a forward rotational direction, that is, in a direction opposite to that of the first groove (14). Additionally, the second groove (15) is positioned on the outer diameter side more than the first groove (14).

[0050] In the second groove (15), the reverse rotation direction side is formed as an open end (15A) communicating near the center of the outer diameter side wall (13D) of the introduction groove (13). The forward rotation direction side of the second groove (15) is formed as a closed closed end (15B). The depth of the second groove (15) is formed to be constant in the elongation direction.

[0051] In addition, the depths of the spiral groove (12), the introduction groove (13), the first groove (14), and the second groove (15) are approximately the same. For this reason, the spiral groove (12), the introduction groove (13), the first groove (14), and the second groove (15) are given dots of the same density as in FIGS. 2 to FIGS. 5.

[0052] Additionally, the closed end (15B) in one second groove (15) is positioned on the outer diameter side of the closed end (14B) in another first groove (14'), and also overlaps the circumferential center and the diameter direction of the other first groove (14').

[0053] Accordingly, the closed end (14B) in the other first groove (14') is closer to one introduction groove (13) in the circumferential direction than the closed end (15B) in the second groove (15). Additionally, the closed end (15B) in the other second groove (15) is closer to another introduction groove (13') in the circumferential direction than the closed end (14B) in the other first groove (14').

[0054] In addition, the portion other than the spiral groove (12), introduction groove (13), first groove (14), and second groove (15) in the sliding surface (11) is formed as a land (16) having a flat surface arranged on the same plane. The flat surface in this land (16) functions as a sliding surface that substantially slides with the sliding surface (21) in the stop sealing ring (20).

[0055] Next, the prevention of leakage into the inner space (S1) of the fluid to be sealed (F) by the mechanical seal (M) will be explained with reference to FIGS. 3 to 5.

[0056] First, the case where the rotation of the rotating seal ring (10) is stopped will be explained. The stop seal ring (20) is attached to the rotating seal ring (10) side by the elastic member (7). Because of this, the sliding surfaces (11, 21) are in contact with each other, more specifically, the land (16) on the sliding surface (11) and the sliding surface (21).

[0057] Accordingly, the mechanical seal (M) prevents the sealed fluid (F) from leaking from the outer space (S2) into the inner space (S1).

[0058] Meanwhile, air (A) is introduced into the spiral groove (12) from the inner space (S1) through the opening end (12A).

[0059] On the other hand, the fluid to be sealed (F) is introduced into the introduction groove (13) from the outer space (S2) through the opening end (13A). Additionally, the fluid to be sealed (F) is introduced into the first groove (14) from the introduction groove (13) through the opening end (14A). Likewise, the fluid to be sealed (F) is introduced into the second groove (15) from the introduction groove (13) through the opening end (15A).

[0060] Next, the operation of the mechanical seal (M) in the case where the rotating seal ring (10) is rotating at a low speed will be explained.

[0061] A portion of the fluid to be sealed (F) that has entered the introduction groove (13) is supplied from the introduction groove (13) to the sliding surfaces (11, 21). Specifically, the fluid to be sealed (F) within the introduction groove (13) is supplied to the sliding surfaces (11, 21) by receiving a shear force in the rotational direction. As described above, the fluid to be sealed (F) is introduced into the introduction groove (13) even when the rotating sealing ring (10) is stationary. Therefore, when the rotating sealing ring (10) begins to rotate, the fluid to be sealed (F) is sufficiently supplied to the sliding surfaces (11, 21). Meanwhile, the fluid to be sealed (F) is supplied to the introduction groove (13) from the outer space (S2) through the opening end (13A). Because of this, a sufficient amount of fluid to be sealed (F) is maintained in the introduction groove (13).

[0062] Here, the fluid to be sealed (F) between the sliding surfaces (11, 21) flows in a counterclockwise direction relative to the sliding surface (11), that is, in the opposite direction to the rotational direction of the rotating seal ring (10), due to the shear force generated by the relative sliding of the sliding surfaces (11, 21). Furthermore, regarding this relative fluid flow, it will be described simply as fluid flow in the following description.

[0063] In the first groove (14) (see also the first groove (14') in FIG. 3), as indicated by the black arrow, the fluid to be sealed (F) flows toward the closed end (14B) in the first groove (14). At this time, the fluid to be sealed (F) flows along the first groove (14), which is formed in an arc shape, along a concentric arc with the sliding surface (11). Accordingly, within the first groove (14), dynamic pressure mainly of the circumferential component is generated. In other words, in the first groove (14), it is difficult for dynamic pressure of the radial component to be generated.

[0064] And, the sealed fluid (F) flowing along the first groove (14) flows out from the closed end (14B) between the land (16) and the sliding surface (21) on the sliding surface (11), as indicated by the black arrow. Accordingly, static pressure is generated at the closed end (14B). In addition, static pressure in this embodiment refers to a relative static pressure that is higher than the surrounding pressure.

[0065] Meanwhile, in the first groove (14), as indicated by the black arrow, the fluid to be sealed (F) is supplied from the introduction groove (13) through the opening end (14A). Because of this, a sufficient amount of the fluid to be sealed (F) is maintained in the first groove (14).

[0066] Additionally, a portion of the sealed fluid (F) in the first groove (14) is supplied between the sliding surfaces (11, 21) from the open end (14A) side rather than the closed end (14B) in the first groove (14).

[0067] In the second groove (15) (see also the second groove (15') in FIG. 3), as indicated by the black arrow, the fluid to be sealed (F) flows toward the opening end (15A) in the second groove (15). At this time, the fluid to be sealed (F) flows along the second groove (15), which is formed in an arc shape, along a concentric arc with the sliding surface (11). Accordingly, it is difficult for dynamic pressure of the radial component to be generated within the second groove (15).

[0068] And, the sealed fluid (F) flowing along the second groove (15) is introduced into the introduction groove (13) through the opening end (15A), as indicated by the black arrow.

[0069] Meanwhile, negative pressure is generated at the closed end (15B) in the second groove (15). Accordingly, as indicated by the black arrow, a portion of the fluid to be sealed (F) between the land (16) of the sliding surface (11) and the sliding surface (21) flows from the closed end (15B) into the second groove (15). Because of this, a sufficient amount of fluid to be sealed (F) is maintained in the second groove (15). Furthermore, in this embodiment, negative pressure refers to a relative negative pressure that is lower than the surrounding pressure.

[0070] Additionally, a portion of the sealed fluid (F) in the second groove (15) is supplied between the sliding surfaces (11, 21) from the open end (15A) side rather than the closed end (15B) in the second groove (15).

[0071] In this way, in addition to the supply of the fluid to be sealed (F) from the introduction groove (13), the fluid to be sealed (F) is also supplied between the sliding surfaces (11, 21) from the first groove (14) and the second groove (15). For this reason, compared to a configuration having only the introduction groove (13) as in Patent Document 1, the efficiency of forming a liquid film is good.

[0072] Additionally, since positive pressure is generated at the closed end (14B) of the first groove (14), the mechanical seal (M) is made to make it easier to introduce the fluid to be sealed (F) between the sliding surfaces (11, 21). On the other hand, since negative pressure is generated at the closed end (15B) of the second groove (15), the mechanical seal (M) prevents the sliding surfaces (11, 21) from separating excessively.

[0073] Additionally, the blocking end (14B) in the other first groove (14') is positioned close to one introduction groove (13). Because of this, the fluid to be sealed (F) supplied from the blocking end (14B) to the sliding surface (11, 21) has a small amount of movement in the radial direction. In this respect, the fluid to be sealed (F) flows to one introduction groove (13) located downstream in the flow direction. Accordingly, the other first groove (14') can efficiently recover the fluid to be sealed (F) to one introduction groove (13).

[0074] In addition, the introduction groove (13), which is inclined in the reverse rotation direction from the outer diameter side toward the inner diameter side, is designed to facilitate the guidance of the fluid to be sealed (F), which intends to move in the reverse rotation direction from the opening end (13A) side, to the first groove (14) by the reverse rotation side wall (13C). In this respect, static pressure is stably generated at the closing end (14B).

[0075] In addition, most of the fluid to be sealed (F) that flows into the introduction groove (13) through the opening end (15A) in the second groove (15) flows into the first groove (14) or is returned to the outside space (S2) from the opening end (13A) of the introduction groove (13). Accordingly, the fluid to be sealed (F) in the second groove (15) is unlikely to stagnate. In this respect, negative pressure is stably generated at the closing end (15B).

[0076] In addition, in an inside type mechanical seal, the fluid to be sealed (F), which has a specific gravity greater than that of the atmosphere (A), is easily pushed out into the outer space (S2) by centrifugal force. For this reason, the second groove (15) located on the outer diameter side is designed to easily recover the fluid to be sealed (F) supplied between the sliding surfaces (11, 21).

[0077] Meanwhile, in the spiral groove (12), as indicated by the white arrow, the atmosphere (A) moves to the closed end (12B), and a static pressure is generated at the closed end (12B). Consequently, as the atmosphere (A) flows between the sliding surfaces (11, 21), the fluid to be sealed (F) near the spiral groove (12) is returned to the outer diameter side.

[0078] Accordingly, as schematically shown by the two-dot dashed line in FIG. 3, a liquid film is formed on the outer diameter side of the circumferential area along the closed end (12B) in each spiral groove (12), and a gas film is formed on the inner diameter side.

[0079] As described above, when the rotary sealing ring (10) rotates at a low speed, the mechanical seal (M) prevents the fluid to be sealed (F) from leaking into the inner space (S1). In addition, by ensuring lubricity between the sliding surfaces (11, 21), wear between the sliding surfaces (11, 21) can be suppressed.

[0080] Next, we will explain how to prevent leakage into the inner space (S1) of the fluid to be sealed (F) by the mechanical seal (M) when the rotary seal ring (10) is rotating at high speed. Additionally, explanations that overlap with low-speed rotation will be omitted or simplified.

[0081] As shown in FIG. 4, a higher static pressure is generated at the closed end (12B) of the spiral groove (12) than when rotating at the aforementioned low speed. Accordingly, as indicated by the white arrow, the air (A) supplied between the sliding surfaces (11, 21) is supplied to the outer diameter side more than when rotating at the low speed. Then, it flows into the introduction groove (13), the first groove (14), and the second groove (15).

[0082] On the other hand, when rotating at a low speed, most of the sealed fluid (F) supplied between the sliding surfaces (11, 21) is pushed into the atmosphere (A) and discharged into the outer space (S2).

[0083] Because of this, at the closed end (14B) of the first groove (14), air (A) flows out between the land (16) and the sliding surface (21) on the sliding surface (11). Likewise, at the closed end (15B) of the second groove (15), air (A) is recovered into the second groove (15). And, most of the air (A) recovered into the second groove (15) flows into the first groove (14) through the introduction groove (13).

[0084] Accordingly, as schematically shown by the two-dot dashed line in FIG. 4, a liquid film and a gas film are formed along the circumferential area along the outer diameter end of each second groove (15).

[0085] As described above, when the rotary seal ring (10) rotates at high speed, the mechanical seal (M) can ensure lubrication between the sliding surfaces (11, 21) through the gas film, thereby suppressing wear between the sliding surfaces (11, 21).

[0086] Next, the operation when the rotating seal ring (10) is rotating in reverse, in particular the prevention of leakage into the inner space (S1) of the fluid to be sealed (F), will be explained. Additionally, explanations that overlap with those for the case of forward rotation will be omitted or simplified.

[0087] As with the case of forward rotation, the sealing fluid (F) is supplied between the sliding surfaces (11, 21) from the introduction groove (13), the first groove (14), and the second groove (15).

[0088] As shown in FIG. 5, the sealing fluid (F) flowing between the sliding surfaces (11, 21) flows clockwise with respect to the sliding surface (11), that is, in the opposite direction to the rotation direction of the rotating seal ring (10).

[0089] In the second groove (15) (see also the second groove (15') in FIG. 5), as indicated by the black arrow, the fluid to be sealed (F) flows toward the closed end (15B) of the second groove (15). Accordingly, it is difficult for dynamic pressure of the radial component to be generated within the second groove (15).

[0090] And, the sealed fluid (F) flowing along the second groove (15) flows out from the closed end (15B) between the land (16) of the sliding surface (11) and the sliding surface (21), as indicated by the black arrow. Accordingly, positive pressure is generated at the closed end (15B).

[0091] Meanwhile, in the second groove (15), as indicated by the black arrow, the fluid to be sealed (F) is supplied from the introduction groove (13) through the opening end (15A). Because of this, a sufficient amount of the fluid to be sealed (F) is maintained in the second groove (15).

[0092] In the first groove (14) (see also the first groove (14') in FIG. 5), as indicated by the black arrow, the fluid to be sealed (F) flows toward the opening end (14A) in the first groove (14). Accordingly, it is difficult for dynamic pressure of the radial component to be generated within the first groove (14).

[0093] And, the sealed fluid (F) flowing along the first groove (14) is introduced into the introduction groove (13) through the opening end (14A), as indicated by the black arrow.

[0094] Meanwhile, negative pressure is generated at the closed end (14B) of the first groove (14). Accordingly, as indicated by the black arrow, a portion of the fluid to be sealed (F) between the land (16) of the sliding surface (11) and the sliding surface (21) flows from the closed end (14B) into the first groove (14). Because of this, a sufficient amount of fluid to be sealed (F) is maintained in the first groove (14).

[0095] In addition, due to the static pressure generated in the second groove (15), the sealed fluid (F) in the introduction groove (13) is made easy to supply to the second groove (15).

[0096] For this reason, compared to a configuration having only an introduction groove (13) as in Patent Document 1, the amount of fluid to be sealed (F) flowing into the inner diameter side wall (13B) of the introduction groove (13) per short time is reduced. Accordingly, the fluid to be sealed (F) is made difficult to leak into the inner space (S1) from the mechanical seal (M).

[0097] Additionally, the closed end (15B) of one second groove (15) is positioned close to another introduction groove (13'). Because of this, the fluid to be sealed (F) supplied from the closed end (15B) to the sliding surface (11, 21) has a small amount of movement in the radial direction. At this point, the fluid to be sealed (F) flows to another introduction groove (13') located downstream in the flow direction. Accordingly, one second groove (15) can efficiently recover the fluid to be sealed (F) to the other introduction groove (13').

[0098] Additionally, the sealed fluid (F) that flows out between the sliding surfaces (11, 21) from the closed end (15B) of one second groove (15) flows into the other first groove (14') even if it flows towards the inner diameter. Accordingly, it flows into the other first groove (14') and is recovered into the other introduction groove (13').

[0099] Likewise, the closed end (14B) of the other first groove (14') is positioned at the circumferential center of one second groove (15). Because of this, the other first groove (14') can recover the sealed fluid (F) supplied between the sliding surfaces (11, 21) from the open end (15A) side rather than the closed end (15B) of one second groove (15) over a wide range.

[0100] The sealing fluid (F) supplied between the sliding surfaces (11, 21) from the inner diameter side of the second groove (15) of one introduction groove (13) is recovered by the negative pressure generated at the closed end (14B) in another first groove (14') located downstream in the direction of flow.

[0101] Additionally, the closing end (14B) of the other first groove (14') is positioned close to one introduction groove (13). Accordingly, the other first groove (14') can efficiently recover the sealing fluid (F) supplied directly between the sliding surfaces (11, 21) from one introduction groove (13).

[0102] Additionally, the introduction groove (13), which is inclined in a forward rotational direction from the inner diameter side toward the outer diameter side, is designed to facilitate the guidance of the fluid to be sealed (F), which intends to move in a forward rotational direction from the first groove (14) side, to the second groove (15) by the forward rotational side wall (13D). Accordingly, it is designed to facilitate the introduction of the fluid to be sealed (F) from the vicinity of the inner diameter side wall (13B), which is closest to the spiral groove (12) within the introduction groove (13), toward the opening end (13A).

[0103] Additionally, the fluid to be sealed (F) introduced from the first groove (14) into the introduction groove (13) is introduced into the second groove (15) or returned to the outside space (S2) from the opening end (13A) in the introduction groove (13). Accordingly, the fluid to be sealed (F) in the first groove (14) is made difficult to stagnate. In this respect, negative pressure is stably generated at the closing end (14B).

[0104] In this way, when the rotating seal ring (10) rotates in reverse, the mechanical seal (M) prevents the fluid to be sealed (F) from leaking into the inner space (S1). In addition, by ensuring lubricity between the sliding surfaces (11, 21), wear between the sliding surfaces (11, 21) can be suppressed.

[0105] The mechanical seal (M) of the present embodiment configured as described above can efficiently introduce the sealing fluid (F) introduced into one introduction groove (13) into another introduction groove (13') through the second groove (15) and another first groove (14'), compared to the configuration in which only lands are formed between adjacent introduction grooves as in Patent Document 1.

[0106] Accordingly, when the rotary sealing ring (10) is rotating in reverse, the fluid to be sealed (F) supplied between the sliding surfaces (11, 21) is recovered into another introduction groove (13') through one second groove (15) and another first groove (14'). In this way, the first groove (14, 14', …) and the second groove (15, 15', …) can contribute to preventing leakage of the fluid to be sealed (F) into the inner space (S1) through the spiral groove (12).

[0107] Additionally, the first groove (14, 14', …) and the second groove (15, 15', …) are configured so that dynamic pressure of the radial component is difficult to generate in either rotational direction. Additionally, the introduction groove (13) is positioned in the elongation direction of the first groove (14) and the second groove (15). Because of this, the other first groove (14') and one second groove (15) are configured to facilitate the flow of the sealing fluid (F) introduced into one introduction groove (13) into the other introduction groove (13').

[0108] In addition, the introduction groove (13), the first groove (14), and the second groove (15) have approximately the same depth as described above. Because of this, the flow of the fluid to be sealed (F) in the introduction groove (13), the first groove (14), and the second groove (15) is smooth, whether the rotation direction of the rotating sealing ring (10) is forward rotation or reverse rotation.

[0109] Additionally, the spiral groove (12), the introduction groove (13), the first groove (14), and the second groove (15) are formed in the rotating sealing ring (10). Because of this, the positions of the spiral groove (12), the introduction groove (13), the first groove (14), and the second groove (15) do not change even when rotating relative to each other, so the fluid to be sealed (F) introduced into the introduction groove (13) can be smoothly introduced into another introduction groove (13') through the first groove (14) and the second groove (15).

[0110] Compared to a configuration in which a spiral groove (12), an inlet groove (13), a first groove (14), and a second groove (15) are formed in a stationary sealing ring (20), the rotational force of the rotating sealing ring (10) is applied directly to the fluid to be sealed (F) that flows into the spiral groove (12), the inlet groove (13), the first groove (14), and the second groove (15), so that dynamic pressure is easily generated.

[0111] In addition, in this embodiment, the spiral groove (12), the introduction groove (13), the first groove (14), and the second groove (15) have been described as having approximately the same depth, but are not limited thereto and may be appropriately modified.

[0112] Additionally, although the spiral groove (12), introduction groove (13), first groove (14), and second groove (15) have been described as having a constant depth in the elongation direction, they are not limited thereto and may have a gradually changing depth or a stepped shape.

[0113] Example 2

[0114] Next, the sliding element according to Example 2 will be described with reference to FIG. 6. In addition, the description of the same configuration as Example 1 and the redundant configuration will be omitted.

[0115] The sliding surface (111) of the rotary sealing ring (110) of the present embodiment 2 is composed of a plurality of spiral grooves (12), a plurality of introduction grooves (113), a plurality of first grooves (14), a plurality of second grooves (15), and a land (116).

[0116] The introduction groove (113) is a rectangular groove extending inward from an opening end communicating with the outer space (S2).

[0117] Accordingly, whether the rotary sealing ring (110) rotates in the forward direction or in the reverse direction, approximately the same amount of sealing fluid (F) is supplied to the introduction groove (113) from the outer space (S2). Because of this, whether the rotary sealing ring (110) rotates in the forward direction or in the reverse direction, the introduction groove (113) is designed to easily ensure stable lubrication between the sliding surfaces (111, 21).

[0118] In this way, the shape of the inlet groove may be appropriately modified.

[0119] Example 3

[0120] Next, the sliding element according to Example 3 will be described with reference to FIG. 7. In addition, descriptions of configurations identical to or overlapping with those of Examples 1 and 2 will be omitted.

[0121] The sliding surface (211) of the rotary sealing ring (210) of the present embodiment 3 is composed of a plurality of spiral grooves (12), a plurality of first introduction grooves (217), a plurality of second introduction grooves (218), a plurality of first grooves (14), a plurality of second grooves (15), and a land (216).

[0122] The first introduction groove (217) is a rectangular groove extending in the inner diameter direction from an opening end communicating with the outer space (S2). Additionally, the first groove (14) is communicating with the first introduction groove (217).

[0123] The second introduction groove (218) is a rectangular groove extending in the inner diameter direction from an opening end communicating with the outer space (S2). Additionally, the second groove (15) is communicating with the second introduction groove (218).

[0124] Accordingly, when the rotary sealing ring (210) is rotating in the forward direction, the fluid to be sealed (F) is supplied to the first groove (14) through the first introduction groove (217). Additionally, the fluid to be sealed (F) is returned from the second groove (15) to the outer space (S2) through the first introduction groove (217).

[0125] In this way, the flow direction of the fluid to be sealed (F) in the first introduction groove (217) and the flow direction of the fluid to be sealed (F) in the second introduction groove (218) can be made different.

[0126] For this reason, the first introduction groove (217) and the second introduction groove (218), which are not in communication with each other, can prevent the dynamic pressure generated at one side of the first groove (14) and the second groove (15) from interfering with the sealed fluid (F) at the other side.

[0127] In this way, the inlet groove may be divided into two or more. In other words, it may be arranged so that only one side of the first groove and the second groove is connected to a single inlet groove.

[0128] Example 4

[0129] Next, the sliding element according to Example 4 will be described with reference to FIG. 8. In addition, descriptions of configurations identical to or overlapping with Examples 1 to 3 will be omitted.

[0130] The sliding surface (311) of the rotary sealing ring (310) of the present embodiment 4 is composed of a plurality of spiral grooves (12), a plurality of introduction grooves (313), a plurality of first grooves (314), a plurality of second grooves (315), and a land (316).

[0131] The first groove (314) is provided at approximately the same position in the radial direction as the second groove (315), that is, on the elongation direction of the second groove (315). Additionally, the first groove (314) is spaced apart from the second groove (315) in the circumferential direction. In other words, the first groove (314) and the second groove (315) do not overlap in the radial direction.

[0132] Accordingly, when the rotating seal ring (310) is rotating in the forward direction, positive pressure is generated in the first groove (314). Because of this, the fluid to be sealed (F) in the introduction groove (313) is easily supplied to the first groove (314).

[0133] Additionally, negative pressure is generated in the second groove (315). Because of this, the sealing fluid (F) supplied from the first groove (314) to the sliding surface (311, 21) is recovered into the second groove (315).

[0134] In addition, when the rotating seal ring (310) is rotating in reverse, positive pressure is generated in the second groove (315). Because of this, the fluid to be sealed (F) in the introduction groove (313) is easily supplied to the second groove (315).

[0135] Additionally, negative pressure is generated in the first groove (314). Because of this, the sealing fluid (F) supplied from the second groove (315) to the sliding surface (311, 21) is recovered into the first groove (314).

[0136] In this way, the diametrical positions of the first and second grooves may be appropriately changed.

[0137] Example 5

[0138] Next, the sliding element according to Example 5 will be described with reference to FIG. 9. In addition, descriptions of configurations identical to or overlapping with Examples 1 to 4 will be omitted.

[0139] The sliding surface (411) of the rotary sealing ring (410) of the present embodiment 5 is composed of a plurality of spiral grooves (12), a plurality of introduction grooves (413), a plurality of second grooves (415), and a land (416).

[0140] The second groove (415) is extended to the vicinity of an adjacent introduction groove (413) located on the forward rotation side, where the closed end (415B) is located.

[0141] Accordingly, when the rotary sealing ring (410) is rotating in the forward direction, the fluid to be sealed (F) is supplied from the introduction groove (413) and the second groove (415) to the sliding surface (411, 21).

[0142] Additionally, when the rotating seal ring (410) is rotating in reverse, the sealing fluid (F) supplied from the second groove (415) to the sliding surface (411, 21) is recovered to an adjacent introduction groove (413) located downstream in the direction of flow.

[0143] In addition, due to the static pressure generated in the second groove (415), the fluid to be sealed (F) in the introduction groove (413) is made easy to supply to the second groove (415).

[0144] In this way, the groove means may be composed of only the second groove. Likewise, the groove means may be composed of only the first groove.

[0145] Example 6

[0146] Next, the sliding element according to Example 6 will be described with reference to FIG. 10. In addition, descriptions of configurations identical to or overlapping with those in Examples 1 to 5 will be omitted.

[0147] The sliding surface (511) of the rotary sealing ring (510) of the present embodiment 6 is composed of a plurality of spiral grooves (12), a plurality of introduction grooves (513), a plurality of third grooves (519) as groove means, and a land (516).

[0148] The third groove (519) is arranged on the outer diameter side of the sliding surface (511), just like the second groove (15) in the above embodiment 1.

[0149] The third groove (519) is a groove that extends circumferentially in a concentric shape with the rotational sealing ring (510). Additionally, the third groove (519) has a blocking end (519A) located on the reverse rotation direction side and a blocking end (519B) located on the forward rotation direction side. That is, the third groove (519) does not communicate with the introduction groove (513) located on the reverse rotation direction side and the introduction groove (513) located on the forward rotation direction side that are adjacent circumferentially.

[0150] When the rotating seal ring (510) is rotating in the forward direction, positive pressure is generated at the closed end (519A) and negative pressure is generated at the closed end (519B).

[0151] Accordingly, the sealing fluid (F) supplied from the introduction groove (513) on the forward rotation direction side to the sliding surface (511, 21) is recovered to the blocking end (519B) located downstream in the flow direction. Additionally, the sealing fluid (F) discharged from the blocking end (519A) to the sliding surface (511, 21) is recovered to the introduction groove (513) on the reverse rotation direction side located downstream in the flow direction.

[0152] Additionally, when the rotating seal ring (510) is rotating in reverse, negative pressure is generated at the closed end (519A) and positive pressure is generated at the closed end (519B).

[0153] Accordingly, the fluid to be sealed (F) supplied from the introduction groove (513) on the reverse rotation direction side to the sliding surface (511, 21) is recovered to the blocking end (519A) located downstream in the flow direction. Additionally, the fluid to be sealed (F) supplied from the blocking end (519B) to the sliding surface (511, 21) is recovered to the introduction groove (513) on the forward rotation direction side located downstream in the flow direction.

[0154] In this way, the groove means may be configured to assist in the recovery of the sealed fluid (F) through the introduction groove, and may not be connected to the introduction groove.

[0155] Example 7

[0156] Next, the sliding element according to Example 7 will be described with reference to FIG. 11. In addition, descriptions of configurations identical to or overlapping with those in Examples 1 to 6 will be omitted.

[0157] The sliding surface (611) of the rotary sealing ring (610) of the present embodiment 7 is composed of a plurality of deep grooves (612) which are part of the dynamic pressure generating groove, a Rayleigh step (632) which is part of the dynamic pressure generating groove, a plurality of introduction grooves (13), a plurality of first grooves (14) which are part of the groove means, a plurality of second grooves (15) which are part of the groove means, and a land (616).

[0158] The core (612) is a rectangular groove in which the opening end on the inner diameter side communicates with the inner space (S1) and extends outward from the opening end. The core (612) is equal in diameter on the inner diameter side of the sliding surface (611).

[0159] The depth of the core (612) is formed to a constant depth in the elongation direction. In addition, the depth of the core (612) is deeper than the introduction groove (13), the first groove (14), and the second groove (15). Because of this, the core (612) in FIG. 11 is given a high density of dots.

[0160] The Rayleigh step (632) is an arc-shaped groove extending in the reverse rotational direction in a concentric shape with the rotational seal ring (610) from the opening end. The Rayleigh step (632) is also symmetrically positioned at the center of the sliding surface (611) in the diametrical direction and on the inner side of the first groove (14).

[0161] The forward rotation direction side of the Rayleigh step (632) is formed as an open end that communicates with the reverse rotation direction side of the outer diameter end in the diameter direction of the core (612). Additionally, the reverse rotation direction side of the Rayleigh step (632) is formed as a closed end.

[0162] The depth of the Rayleigh step (632) is formed to a constant depth in the elongation direction. Additionally, the depth of the Rayleigh step (632) is formed shallower than the introduction groove (13), the first groove (14), and the second groove (15). Because of this, the Rayleigh step (632) in FIG. 11 is given low-density dots.

[0163] Accordingly, as the rotating seal ring (610) rotates forward, the atmosphere (A) within the Rayleigh step (632) moves toward the closed end and flows out from the closed end between the sliding surfaces (611, 21), thereby generating positive pressure.

[0164] In addition, air (A) is always stored in the deep hole (612). Accordingly, air (A) flows stably into the Rayleigh step (632). Because of this, the Rayleigh step (632) can stably generate static pressure.

[0165] In this way, the dynamic pressure generating groove is not limited to the spiral groove (12) and may be appropriately modified.

[0166] Additionally, the depth of the deep ball (612) and the Rayleigh step (632) may be appropriately changed.

[0167] Example 8

[0168] Next, the sliding element according to Example 8 will be described with reference to FIG. 12. In addition, descriptions of configurations identical to or overlapping with Examples 1 to 7 will be omitted.

[0169] The mechanical seal of the present embodiment 8 is a so-called outside type mechanical seal in which a fluid to be sealed (F) exists in the inner space (S11) and an atmosphere (A) exists in the outer space (S12).

[0170] The sliding surface (711) in the rotary sealing ring (710) is composed of a plurality of spiral grooves (712), a plurality of introduction grooves (713), a plurality of first grooves (714), a plurality of second grooves (715), and a land (716).

[0171] The spiral groove (712) is arranged evenly on the outer diameter side of the sliding surface (711). The opening end of the spiral groove (712) on the outer diameter side is in communication with the outer space (S12), and extends in the reverse rotation direction based on the point of communication.

[0172] The introduction groove (713) is evenly spaced on the inner diameter side of the sliding surface (711). The opening end of the introduction groove (713) on the inner diameter side is in communication with the inner space (S11), and the reverse rotation direction side is also extended in the outer diameter direction based on the communication point.

[0173] The first groove (714) is symmetrically positioned at the center of the sliding surface (711) in the diametrical direction and also on the inner diameter side of the spiral groove (712). The opening end of the first groove (714) on the forward rotation direction side is connected to the inner diameter end of the reverse rotation side wall in the introduction groove (713), and extends in the reverse rotation direction based on the connection point.

[0174] The second groove (715) is equal in diameter on the inner side of the sliding surface (711). The opening end of the second groove (715), located on the reverse rotation direction side, communicates near the center of the inner diameter of the forward rotation side wall in the introduction groove (713), and extends toward the forward rotation direction side based on the communication point.

[0175] When the rotating seal ring (710) is rotating in the forward direction, positive pressure is generated at the closed end of the spiral groove (712).

[0176] The introduction groove (713) introduces the fluid to be sealed (F) between the sliding surfaces (711, 21). Additionally, positive pressure is generated at the closed end of the first groove (714). Additionally, negative pressure is generated at the closed end of the second groove (715).

[0177] Accordingly, the lubricity of a pair of sliding surfaces (711, 21) is improved, whether the relative rotation is at a low speed or the relative rotation is at a high speed.

[0178] Additionally, when the rotating seal ring (710) is rotating in reverse, negative pressure is generated at the closed end of the first groove (714). Additionally, positive pressure is generated at the closed end of the second groove (715).

[0179] Accordingly, the sealed fluid (F) is recovered into the introduction groove (713) through the first groove (714) and the second groove (715).

[0180] In this way, a pair of sliding surfaces having a dynamic pressure generating groove, an introduction groove, and a groove means may be applied to an outside-type mechanical seal.

[0181] Although embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and changes or additions within the scope that do not deviate from the gist of the present invention are also included in the present invention.

[0182] For example, in the above Examples 1 to 8, a mechanical seal was described as an example of a sliding element, but other mechanical seals such as those for general industrial machinery, automobiles, or water pumps may also be used. Furthermore, it is not limited to mechanical seals, and sliding elements other than mechanical seals, such as sliding bearings, may also be used.

[0183] In addition, although the above embodiments 1 to 8 described the configuration in which the dynamic pressure generating groove, the introduction groove, the first groove, and the second groove are formed on the rotating sealing ring, they are not limited thereto and may be formed on the stationary sealing ring. Furthermore, the dynamic pressure generating groove may be formed on one side of the rotating sealing ring and the stationary sealing ring, and the introduction groove, the first groove, and the second groove may be formed on the other side of the rotating sealing ring and the stationary sealing ring.

[0184] Furthermore, regarding the sliding surface of the stationary sealing ring, the fluid to be sealed flows relatively in the same direction as the relative rotation direction. In this regard, in a configuration where an inlet groove, a first groove, and a second groove are formed in the stationary sealing ring, the first groove extends from the inlet groove in the forward rotation direction, and the second groove extends from the inlet groove in the reverse rotation direction. That is, in the case of relative rotation and forward rotation, the first groove is the groove on the side where the fluid to be sealed flows in from the inlet groove, and the second groove is the groove on the side where the fluid to be sealed flows into the inlet groove.

[0185] In addition, in the above Examples 1 to 8, the fluid to be sealed (F) was 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 state in which liquid and gas are mixed.

[0186] In addition, in the above Examples 1 to 8, the fluid on the leakage side was described as an atmosphere that is a low-pressure gas, but it is not limited thereto and may be a liquid or a high-pressure gas, or may be a mist state in which liquid and gas are mixed.

[0187] In addition, in the above Examples 1 to 8, the first groove and the second groove were described as having a configuration in which positive pressure or negative pressure is generated at each closed end, but are not limited thereto and may have a configuration in which little or no positive pressure or negative pressure is generated.

[0188] In addition, in the above embodiments 1 to 8, the first groove and the second groove were described as having an arc shape, but are not limited thereto; they may have a straight line shape or a broken line shape, and the shape may be appropriately changed. Explanation of the symbols

[0189] 10; Rotating seal ring 11; sliding surface 12; Spiral groove (dynamic pressure generating groove) 13, 13'; Introduction Home 14, 14'; 1st home (home means) 15, 15'; second home (home means) 20; Stop seal ring 21; sliding surface 110~710; Rotating sealing ring 111~711; Sliding surface 113~713; Introduction Home 217; 1st Introduction Home 218; 2nd Introduction Home 314, 714; 1st home (home means) 415, 715; 2nd home (home means) 519; 3rd home (home means) 612; Deep groove (dynamic pressure generating groove) 632; Rayleigh step (dynamic pressure generating groove) 712; Spiral groove (dynamic pressure generating groove) A; Waiting F; sealed fluid M; Mechanical Seal S1, S11; inner space (space on the leakage side) S2, S12; outer space (space on the fluid side to be sealed)

Claims

Claim 1 A pair of sliding members each having sliding surfaces that slide by relative rotation, wherein at least one of the sliding surfaces has a plurality of inlet grooves communicating with a space on the fluid to be sealed side, and at least one of the sliding surfaces has a dynamic pressure generating groove communicating with a space on the leakage side, wherein the sliding surface having the inlet groove is further provided with a groove means disposed on the fluid to be sealed side rather than the dynamic pressure generating groove and enabling the fluid to be sealed to flow between adjacent inlet grooves, wherein the relative rotation of the sliding surface on the opposite side with respect to the one sliding surface includes forward rotation and reverse rotation, and the relative rotation direction during forward rotation and the relative rotation direction during reverse rotation are opposite to each other, wherein the groove means has a first groove extending from the inlet groove and generating static pressure during forward rotation, and a second groove extending from the inlet groove in a direction opposite to that of the first groove and generating static pressure during reverse rotation, and the end of the first groove extending from one of the inlet grooves is the same as the one extending from the adjacent inlet groove A sliding element positioned on the leakage side above the end of the second groove. Claim 2 In claim 1, the first groove and the second groove are sliding elements that extend in an arc shape. Claim 3 In claim 1 or 2, the end portion in the first groove of one of the above-mentioned grooves is a sliding element positioned on the leakage side rather than the end portion in the second groove of the adjacent above-mentioned groove. Claim 4 In claim 1, the first groove of one of the above-mentioned introduction grooves is a sliding element arranged to partially overlap in the diameter direction with the second groove of the adjacent above-mentioned introduction groove. Claim 5 In claim 1 or 2, the introduction groove, the first groove, and the second groove are sliding elements having the same depth. Claim 6 In claim 1, one of the above sliding members is a sliding element having the above introduction groove, the above dynamic pressure generating groove, and the above groove means. Claim 7 In claim 1, the above-mentioned introduction groove is a sliding element that extends at an angle with respect to the diameter direction from the sealing side toward the leakage side. Claim 8 In claim 1, the above-mentioned introduction groove is a sliding element that extends parallel to the diameter direction from the sealing side toward the leakage side. Claim 9 A sliding element according to claim 1, wherein the introduction groove is formed by a first introduction groove portion and a second introduction groove portion extending independently and parallel to each other, and the first groove is in communication with the first introduction groove portion and the second groove is in communication with the second introduction groove portion.

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