Patent ID: 12188516

DESCRIPTION OF EMBODIMENTS

Modes for carrying out a sliding component according to the present invention will be described below on the basis of the embodiments.

First Embodiment

A sliding component according to a first embodiment of the present invention will be described with reference toFIGS.1to6. Additionally, in this embodiment, an embodiment in which a sliding component is a mechanical seal will be described as an example. Further, a description will be made such that a sealing target fluid exists in an outer space of the mechanical seal, an atmosphere exists in an inner space, an outer radial side of the sliding component constituting the mechanical seal is a sealing target fluid side (i.e., high pressure side), and an inner radial side is a leakage side (i.e., low pressure side). Further, for convenience of description, in the drawings, dots may be added to a groove and the like formed on a sliding surface.

A mechanical seal for automobiles shown inFIG.1is of an inside type that seals a sealing target fluid F tending to leak from the outer radial side toward the inner radial side of the sliding surface and allows an inner space S1to communicate with an atmosphere A. Additionally, in this embodiment, an embodiment in which the sealing target fluid F is a high-pressure liquid and the atmosphere A is a gas having a pressure lower than that of the sealing target fluid F is illustrated.

The mechanical seal mainly includes a rotating seal ring20which is the other annular sliding component provided in a rotary shaft1through a sleeve2to be rotatable together with the rotary shaft1and an annular stationary seal ring10which is a sliding component provided in a seal cover5fixed to a housing4of an attachment target device not to be rotatable and to be movable in the axial direction and when an elastic member7urges the stationary seal ring10in the axial direction, a sliding surface11of the stationary seal ring10and a sliding surface21of the rotating seal ring20slide closely with each other. Additionally, the sliding surface21of the rotating seal ring20is formed as a flat surface and this flat surface is not provided with a concave portion such as a groove.

The stationary seal ring10and the rotating seal ring20are typically formed of SiC (hard material) or a combination of SiC (hard material) and carbon (soft material). However, the present invention is not limited thereto and any sliding material can be applied insofar as it is used as a sliding material for a mechanical seal. It should be noted that the SiC includes a sintered body using boron, aluminum, carbon, or the like as a sintering aid and a material made of two or more types of phases having different components and compositions, examples of which include SiC in which graphite particles are dispersed, reaction-sintered SiC made of SiC and Si, SiC—TiC, and SiC—TiN. As the carbon, resin-molded carbon, sintered carbon, and the like can be used, including carbon in which carbon and graphite are mixed. In addition to the above sliding materials, a metal material, a resin material, a surface modification material (coating material), a composite material, and the like can also be applied.

As shown inFIGS.2and3, the rotating seal ring20slides relative to the stationary seal ring10counterclockwise as indicated by the solid arrow or clockwise as indicated by the dotted arrow, a plurality of dynamic pressure generation grooves13and inclined grooves13′ are evenly arranged in the circumferential direction on the inner radial side of the sliding surface11of the stationary seal ring10, and a plurality of fluid introduction grooves16are evenly arranged in the circumferential direction on the outer radial side.

Hereinafter, in the embodiments, the counterclockwise rotation direction of the rotating seal ring20indicated by the solid arrow will be described as the normal rotation direction and the clockwise rotation direction of the rotating seal ring20indicated by the dotted arrow will be described as the reverse rotation direction.

Further, a portion other than the dynamic pressure generation groove13, the inclined groove13′, and a fluid introduction groove16of the sliding surface11is formed as a land12forming a flat surface. Specifically, the land12includes a land portion12aformed between the adjacent dynamic pressure generation grooves13, the adjacent inclined grooves13′, and the dynamic pressure generation groove13and the inclined groove13′ in the circumferential direction, a land portion12bformed between the adjacent fluid introduction grooves16in the circumferential direction, and a land portion12cformed between the inclined groove13′ and the fluid introduction groove16separated from each other in the radial direction and these land portions are arranged on the same plane and constitute the flat surface of the land12.

As shown inFIG.3, the dynamic pressure generation groove13is formed such that an outer radial end13B extends to the land portion12bbetween the adjacent fluid introduction grooves16in the circumferential direction, includes an inclined groove14which extends from the inner radial side toward the outer radial side and generates a dynamic pressure and a reverse inclined groove15which is a concave portion continuously formed on the outer radial side of the inclined groove14, extending in the reverse direction with respect to the inclined groove14, and generating a dynamic pressure, and is formed in an L shape. In addition, the reverse inclined groove15which is the concave portion is disposed between the adjacent fluid introduction grooves16in the circumferential direction.

Further, extending in the reverse direction with respect to the inclined groove14means that the reverse inclined groove15obliquely extends while having a component in the reverse rotation direction from the inner radial side toward the outer radial side with respect to the inclined groove14obliquely extending while having a component in the normal rotation direction from the inner radial side toward the outer radial side.

Specifically, the dynamic pressure generation groove13extends in an arc shape while being inclined in the normal rotation direction of the rotating seal ring20from an inner radial end13A toward the outer radial side by allowing the inner radial end13A, that is, the inner radial end of the inclined groove14to communicate with the inner space S1and the reverse inclined groove15is continuously formed on the outer radial end portion of the inclined groove14to extend in the reverse direction with respect to the inclined groove14. The reverse inclined groove15extends in a linear shape while being inclined in the reverse rotation direction of the rotating seal ring20from the inner radial end portion toward the outer radial side and is closed so that the outer radial end portion, that is, the outer radial end13B of the dynamic pressure generation groove13does not communicate with the outer space S2. In addition, the reverse inclined groove15is not limited to the one obliquely extending in a linear shape and may be one extending in an arc shape.

As shown inFIG.3, the inclined groove14includes a bottom surface14awhich is flat in the extension direction and is parallel to the flat surface of the land12and side wall portions14cand14dwhich perpendicularly extend from both side edges of the bottom surface14atoward the sliding surface11.

The reverse inclined groove15includes a bottom surface15awhich is flat in the extension direction and is parallel to the flat surface of the land12, a wall portion15bwhich extends perpendicularly from the end edge on the side of the outer radial end13B in the bottom surface15atoward the sliding surface11, and side wall portions15cand15dwhich extend perpendicularly from both side edges of the bottom surface15atoward the sliding surface11.

Further, the dynamic pressure generation groove13is provided with an acute angle portion13C which is formed by the side wall portion14dof the inclined groove14and the side wall portion15dof the reverse inclined groove15, an acute angle portion13D which is formed by the wall portion15band the side wall portion15cof the reverse inclined groove15, and an obtuse angle portion13E which is formed by the wall portion15band the side wall portion15dof the reverse inclined groove15and the acute angle portion13D is located on the outer radial side of the acute angle portion13C and the downstream side in the reverse rotation direction of the rotating seal ring20. Further, the angle of the acute angle portion13D is smaller than that of the acute angle portion13C. In addition, the acute angle portion13C is formed at substantially the same radial position as an inner radial peripheral wall portion17aof a liquid guide groove portion17of the fluid introduction groove16to be described later and the acute angle portion13D is formed at substantially the same radial position as an outer radial peripheral wall portion18aof a Rayleigh step18of the fluid introduction groove16to be described later.

Further, the extension length of the reverse inclined groove15in its inclined direction is shorter than the extension length of the inclined groove14in its inclined direction. That is, the length of each of the side wall portions15cand15dof the reverse inclined groove15is shorter than the length of each of the side wall portions14cand14dof the continuous inclined groove14.

Further, the depth of the reverse inclined groove15is the same as the depth of the inclined groove14. That is, the bottom surface15aof the reverse inclined groove15is disposed on the same plane as the bottom surface14aof the continuous inclined groove14and forms a flat surface. In addition, the bottom surface14aof the inclined groove14and the bottom surface15aof the reverse inclined groove15are not limited to the one forming the flat surface and may have an inclination or unevenness.

As shown inFIG.3, the inclined groove13′ is for generating a dynamic pressure while an outer radial end13B′ is disposed on the inner radial side of the fluid introduction groove16and extends from the inner radial side toward the outer radial side.

Specifically, the inclined groove13′ extends in an arc shape while being inclined in the normal rotation direction of the rotating seal ring20from an inner radial end13A′ toward the outer radial side by allowing the inner radial end13A′ to communicate with the inner space S1and an outer radial end13B′ is closed not to communicate with the fluid introduction groove16.

As shown inFIG.3, the inclined groove13′ includes a bottom surface13a′ which is flat in the extension direction and is parallel to the flat surface of the land12, a wall portion13b′ which perpendicularly extends from the end edge on the side of the outer radial end13B′ of the bottom surface13a′ toward the sliding surface11, and side wall portions13c′ and13d′ which perpendicularly extend from both side edges of the bottom surface13a′ toward the sliding surface11.

Further, the inclined groove13′ is provided with an acute angle portion13C′ which is formed by the wall portion13b′ and the side wall portion13d′ and an obtuse angle portion13D′ which is formed by the wall portion13b′ and the side wall portion13c′.

As shown inFIG.3, the fluid introduction groove16includes the liquid guide groove portion17which communicates with the outer space S2and the Rayleigh step18which extends in the circumferential direction concentrically with the stationary seal ring10from the inner radial side of the liquid guide groove portion17toward the normal rotation direction of the rotating seal ring20. In addition, the liquid guide groove portion17and the Rayleigh step18are formed to have substantially the same depth as the depth dimension of the dynamic pressure generation groove13. Further, the circumferential length of the Rayleigh step18is formed to be longer than the circumferential length of the liquid guide groove portion17or the circumferential length of one dynamic pressure generation groove13.

Next, the operation during the relative rotation of the stationary seal ring10and the rotating seal ring20will be described with reference toFIGS.4and5. Additionally, in this embodiment, the rotating seal ring20will be described in order of the stop state, the normal rotation state, and the reverse rotation state.

First, the sealing target fluid F flows into the fluid introduction groove16in the stop state in which the rotating seal ring20does not rotate. In addition, since the elastic member7urges the stationary seal ring10toward the rotating seal ring20, the sliding surfaces11and21are in the contact state and the sealing target fluid F between the sliding surfaces11and21substantially does not leak to the inner space S1.

As shown inFIG.4, since the sealing target fluid F in the Rayleigh step18moves in a following manner in the normal rotation direction of the rotating seal ring20due to shearing with the sliding surface21at the low speed immediately after the rotating seal ring20starts to rotate in the normal rotation direction relative to the stationary seal ring10, the sealing target fluid F in the outer space S2is drawn into the liquid guide groove portion17. That is, in the fluid introduction groove16, the sealing target fluid F moves from the liquid guide groove portion17toward the downstream end portion18A in the relative rotation direction of the Rayleigh step18as indicated by the arrow H1. In addition, the flow of the sealing target fluid F or the atmosphere A ofFIG.4is schematically shown without specifying the relative rotation speed of the rotating seal ring20.

The pressure of the sealing target fluid F having moved toward the end portion18A of the Rayleigh step18is increased at the end portion18A of the Rayleigh step18and in the vicinity thereof. That is, a positive pressure is generated at the end portion18A of the Rayleigh step18and in the vicinity thereof.

Since the depth of the Rayleigh step18is shallow, a positive pressure is generated at the end portion18A of the Rayleigh step18and in the vicinity thereof even when the movement amount of the sealing target fluid F is small when the rotation speed of the rotating seal ring20is low.

Further, the sliding surfaces11and21are slightly separated from each other by a force caused by the positive pressure generated at the end portion18A of the Rayleigh step18and in the vicinity thereof. Accordingly, the sealing target fluid F in the fluid introduction groove16indicated by the arrow H2mainly flows between the sliding surfaces11and21. In this way, since the sealing target fluid F is interposed between the sliding surfaces11and21, lubricity is improved even at a low-speed rotation and the wear between the sliding surfaces11and21can be suppressed.

Additionally, since the levitation distance between the sliding surfaces11and21is small, the amount of the sealing target fluid F leaking into the inner space S1is small. Further, since the liquid guide groove portion17is provided, a large amount of the sealing target fluid F can be held and poor lubrication between the sliding surfaces11and21can be prevented at the low-speed rotation.

On the other hand, in the dynamic pressure generation groove13and the inclined groove13′, when the relative rotation speed of the rotating seal ring20and the stationary seal ring10is low, the atmosphere A is not sufficiently dense in the dynamic pressure generation groove13and the inclined groove13′, a high positive pressure is not generated, and a force caused by the positive pressure generated by the dynamic pressure generation groove13and the inclined groove13′ is relatively smaller than a force caused by the positive pressure generated at the end portion18A of the Rayleigh step18and in the vicinity thereof. Thus, when the rotating seal ring20rotates at a low speed, a force caused by the positive pressure generated at the end portion18A of the Rayleigh step18and in the vicinity thereof mainly serves to separate the sliding surfaces11and21from each other.

When the relative rotation speed of the rotating seal ring20increases, as shown inFIG.4, the atmosphere A in the dynamic pressure generation groove13and the inclined groove13′ moves in a following manner in the normal rotation direction of the rotating seal ring20due to shearing with the sliding surface21and the atmosphere A of the inner space S1is drawn into the dynamic pressure generation groove13and the inclined groove13′. That is, in the dynamic pressure generation groove13and the inclined groove13′, a large amount of the atmosphere A moves as indicated by the arrows L1and L1′ from the inner radial end13A of the inclined groove14toward the outer radial end portion of the inclined groove14and from the inner radial end13A′ of the inclined groove13′ toward the outer radial end13B′.

The pressure of the atmosphere A having moved toward the outer radial end portion of the inclined groove14is increased at the acute angle portion13C and in the vicinity thereof. That is, a positive pressure is generated at the acute angle portion13C and in the vicinity thereof. Further, the pressure of the atmosphere A having moved toward the outer radial end13B′ of the inclined groove13′ is increased at the acute angle portion13C′ and in the vicinity thereof. That is, a positive pressure is generated at the acute angle portion13C′ and in the vicinity thereof.

In this way, a force caused by the positive pressure generated at the acute angle portions13C and13C′ and in the vicinity thereof is added to a force caused by the positive pressure generated at the end portion18A of the Rayleigh step18and in the vicinity thereof and the sliding surfaces11and21are further separated from each other compared to a low-speed state. Accordingly, the atmosphere A in the dynamic pressure generation groove13and the inclined groove13′ indicated by the arrows L2and L2′ mainly flows between the sliding surfaces11and21.

Since the atmosphere A in the dynamic pressure generation groove13and the inclined groove13′ indicated by the arrows L2and L2′ acts to push back the sealing target fluid F in the vicinity of the acute angle portion13C of the dynamic pressure generation groove13and the acute angle portion13C′ of the inclined groove13′ toward the outer space S2, the amount of the sealing target fluid F leaking into the dynamic pressure generation groove13and the inclined groove13′ or the inner space S1is small.

Further, since the atmosphere A in the inclined groove13′ indicated by the arrow L2′ pushes back the sealing target fluid F in the vicinity of the acute angle portion13C′ of the inclined groove13′ toward the outer space S2to enter the Rayleigh step18of the fluid introduction groove16as indicated by the arrow H3, it is possible to suppress the sealing target fluid F from leaking to the inner space S1.

Since the sliding component of this embodiment is designed so that the positive pressure generation ability of the entire inclined grooves14and13′ at the high-speed rotation in the normal rotation direction is sufficiently larger than the positive pressure generation ability of the entire reverse inclined groove15and the positive pressure generation ability of the entire Rayleigh step18, only the atmosphere A finally exists between the sliding surfaces11and21, that is, a gas lubrication is performed.

Next, the reverse rotation state of the rotating seal ring20will be described with reference toFIG.5. As shown inFIG.5, when the rotating seal ring20rotates in the reverse rotation direction relative to the stationary seal ring10, the sealing target fluid F in the Rayleigh step18moves in a following manner in the reverse rotation direction of the rotating seal ring20due to shearing with the sliding surface21and enters the liquid guide groove portion17on the downstream side in the relative rotation direction and a part of the sealing target fluid F in the liquid guide groove portion17flows out to the outer space S2. In addition, the flow of the sealing target fluid F or the atmosphere A ofFIG.5is schematically shown without specifying the relative rotation speed of the rotating seal ring20.

Further, at this time, the sealing target fluid F existing at the land portion12bbetween the adjacent fluid introduction grooves16or the land portion12cbetween the dynamic pressure generation groove13and the fluid introduction groove16separated from each other in the radial direction is sucked into the fluid introduction groove16as indicated by the arrow H2′ due to the negative pressure generated at the end portion18A of the Rayleigh step18and in the vicinity thereof and this tendency becomes remarkable in the vicinity of the end portion18A.

In this way, when the rotating seal ring20rotates counterclockwise in the reverse rotation direction relative to the stationary seal ring10, a large amount of the sealing target fluid F sucked into the fluid introduction groove16is held in the liquid guide groove portion17and poor lubrication between the sliding surfaces11and21can be prevented.

On the other hand, in the dynamic pressure generation groove13, as shown inFIG.5, the sealing target fluid F having entered the reverse inclined groove15formed on the outer radial side of the dynamic pressure generation groove13moves in a following manner in the reverse rotation direction of the rotating seal ring20due to shearing with the sliding surface21. That is, in the dynamic pressure generation groove13, the sealing target fluid F moves toward the acute angle portion13D through the reverse inclined groove15as indicated by the arrow H3′.

The pressure of the sealing target fluid F having moved toward the acute angle portion13D is increased at the acute angle portion13D and in the vicinity thereof. That is, a positive pressure is generated at the acute angle portion13D and in the vicinity thereof.

Further, the sliding surfaces11and21are slightly separated from each other due to a force caused by the positive pressure generated at the acute angle portion13D and in the vicinity thereof. Accordingly, the sealing target fluid F in the fluid introduction groove16indicated by the arrow H4′ mainly flows between the sliding surfaces11and21.

Since the sealing target fluid F flowing out of the acute angle portion13D as indicated by the arrow H4′ acts to push back the sealing target fluid F in the vicinity of the acute angle portion13D of the dynamic pressure generation groove13toward the outer space S2, the amount of the sealing target fluid F leaking into the dynamic pressure generation groove13or the inner space S1is small.

Further, at this time, the sealing target fluid F existing in the vicinity of the acute angle portion13C is sucked into the reverse inclined groove15as indicated by the arrow H5′ due to the negative pressure generated at the acute angle portion13C and in the vicinity thereof. The sealing target fluid F sucked into the reverse inclined groove15is returned between the sliding surfaces11and21from the acute angle portion13D.

Further, the sealing target fluid F introduced into the fluid introduction groove16and flowing out between the sliding surfaces11and21from the vicinity of the liquid guide groove portion17is captured by being sucked into the reverse inclined groove15of the dynamic pressure generation groove13located on the downstream side in the relative rotation direction of the liquid guide groove portion17of the fluid introduction groove16. At this time, since a negative pressure is generated at the acute angle portion13C and in the vicinity thereof, the sealing target fluid F having flowed out between the sliding surfaces11and21is easily sucked into the reverse inclined groove15of the dynamic pressure generation groove13.

Further, the sealing target fluid F having returned between the sliding surfaces11and21from the acute angle portion13D of the dynamic pressure generation groove13located on the upstream side in the relative rotation direction of the Rayleigh step18of the fluid introduction groove16toward the outer radial side is sucked into the fluid introduction groove16as indicated by the arrow H2′ due to the negative pressure generated at the end portion18A of the Rayleigh step18and in the vicinity thereof as described above.

In this way, since the sealing target fluid F is passed between the fluid introduction groove16and the plurality of reverse inclined grooves15and is retained on the outer radial side in such a manner that the reverse inclined grooves15of the plurality of dynamic pressure generation grooves13are arranged between the adjacent fluid introduction grooves16in the circumferential direction in the reverse rotation state, the amount of the sealing target fluid F leaking into the dynamic pressure generation groove13or the inner space S1is small.

In addition, in the inclined groove14, since the inner radial end13A is opened to the inner space S1, the negative pressure generated in the inclined groove14during the reverse rotation of the rotating seal ring20decreases. Further, since the inclined groove14and the reverse inclined groove15are continuous grooves, the sealing target fluid F having entered the dynamic pressure generation groove13is returned between the sliding surfaces11and21from the acute angle portion13D toward the outer radial side due to the flow of the sealing target fluid F in the reverse inclined groove15during the reverse rotation of the rotating seal ring20. Accordingly, the amount of the sealing target fluid F leaking to the inner space S1through the inclined groove14can be reduced.

As described above, when the rotating seal ring20starts to rotate relative to the stationary seal ring10, the sliding surfaces11and21are lubricated by the sealing target fluid F flowing out between the sliding surfaces11and21from the fluid introduction groove16. When the rotating seal ring rotates at a high speed, the sliding surfaces11and21are separated from each other by the positive pressure generated by the atmosphere A in the dynamic pressure generation groove13and the inclined groove13′. Accordingly, it is possible to suppress the wear between the sliding surfaces11and21from the start of the relative rotation to the high-speed rotation.

Further, when the rotating seal ring20rotates in the normal rotation direction, the sealing target fluid F having flowed between the sliding surfaces11and21from the outer space S2is sucked and pushed back toward the outer space S2due to the positive pressure mainly generated in the inclined groove13′ and the inclined groove14of the dynamic pressure generation groove13. Accordingly, it is possible to suppress the sealing target fluid F from leaking to the inner space S1from between the sliding surfaces11and21. On the other hand, when the rotating seal ring20rotates in the reverse rotation direction, the sealing target fluid F having entered the reverse inclined groove15on the outer radial side of the inclined groove14in the dynamic pressure generation groove13moves in a following manner due to shearing with the sliding surface21of the rotating seal ring20and is returned between the sliding surfaces11and21from the end portion on the side of the sealing target fluid F of the reverse inclined groove15, that is, the acute angle portion13D toward the outer radial side. Accordingly, it is possible to reduce the leakage of the sealing target fluid F to the inner space S1. In this way, since the dynamic pressure generation groove13includes the inclined groove14and the reverse inclined groove15having different rotation directions for generating the main dynamic pressure, it is possible to suppress the wear by separating the sliding surfaces11and21from each other during both rotations and to suppress the sealing target fluid F from leaking to the inner space S1from between the sliding surfaces11and21.

Further, in the reverse rotation state, the sealing target fluid F introduced into the fluid introduction groove16and flowing out between the sliding surfaces11and21from the vicinity of the liquid guide groove portion17is captured by being sucked into the reverse inclined groove15of the dynamic pressure generation groove13due to the negative pressure generated at the acute angle portion13C of the dynamic pressure generation groove13located on the downstream side in the relative rotation direction of the liquid guide groove portion17of the fluid introduction groove16and in the vicinity thereof and the sealing target fluid F captured in the reverse inclined groove15moves in a following manner due to shearing with the sliding surface21of the rotating seal ring20and is returned between the sliding surfaces11and21from the acute angle portion13D of the reverse inclined groove15toward the outer radial side. Accordingly, it is possible to further reduce the leakage of the sealing target fluid F to the inner space S1.

Further, since the dynamic pressure generation groove13is formed in an L shape by the inclined groove14and the reverse inclined groove15, it is possible to generate a positive pressure by allowing the acute angle portion13C to accumulate the sealing target fluid F sucked from the acute angle portion13D to the reverse inclined groove15along with the atmosphere A sucked from the inner radial end13A to the inclined groove14in the normal rotation state. Further, since the sealing target fluid F can be pushed back toward the outer space S2by the dynamic pressure generated in the reverse inclined groove15in the reverse rotation state, it is possible to suppress the sealing target fluid F from entering the inclined groove14and to suppress the sealing target fluid F from leaking to the inner space S1through the inclined groove14.

Further, the extension length of the reverse inclined groove15is shorter than that of the inclined groove14. Accordingly, it is possible to generate a positive pressure by the reverse inclined groove15at an early time in the reverse rotation state.

Further, the reverse inclined groove15is a groove including the acute angle portion13D of which the outer radial end portion is tapered. Accordingly, since it is easy to generate a positive pressure by concentrating the sealing target fluid F in the reverse inclined groove15on the acute angle portion13D in the reverse rotation state, it is possible to increase the dynamic pressure effect.

Further, the reverse inclined groove15is provided only at the dynamic pressure generation groove13formed between the adjacent fluid introduction grooves16. Accordingly, the reverse inclined groove15does not exist at the position radially overlapping with the inclined groove13′ disposed on the inner radial side of the fluid introduction groove16and the extension length of the inclined groove13′ disposed on the inner radial side of the fluid introduction groove16can be increased. Therefore, since it is easy to generate a high positive pressure in the inclined groove13′ by the atmosphere A in the normal rotation state, it is possible to increase the dynamic pressure effect.

Further, the inclined grooves14and13′ communicate with the inner space S1. Accordingly, since it is easy to introduce the atmosphere A of the inner space S1from the inner radial ends13A and13A′ to the inclined grooves14and13′ and to generate a positive pressure in the inclined grooves14and13′ by the atmosphere A in the normal rotation state, it is possible to increase the dynamic pressure effect.

Further, the fluid introduction groove16includes the Rayleigh step18. Accordingly, since it is possible to generate the dynamic pressure by the Rayleigh step18in the normal rotation state so that the sliding surfaces11and21are slightly separated from each other and the sealing target fluid F can be introduced between the sliding surfaces11and21, it is possible to improve the lubricity between the sliding surfaces11and21. Further, since the liquid guide groove portion17of the fluid introduction groove16communicates with the outer space S2, it is easy to introduce the sealing target fluid F into the liquid guide groove portion17and to generate the positive pressure by the Rayleigh step18at an early time.

Further, since the Rayleigh step18can suck the sealing target fluid F in the periphery of the end portion18A by the negative pressure in the reverse rotation state and introduce the sealing target fluid into the liquid guide groove portion17, it is possible to suppress the sealing target fluid F from leaking to the inner space S1.

In addition, as a modified example of the stationary seal ring10, as in a stationary seal ring110corresponding to the sliding component shown inFIG.6, this stationary seal ring may be applied to an outside type mechanical seal that seals the sealing target fluid F tending to leak from the inner radial side toward the outer radial side of the sliding surface111in such a manner that a plurality of fluid introduction grooves116are evenly and circumferentially arranged on the inner radial side of the sliding surface111and a plurality of dynamic pressure generation grooves113and inclined grooves113′ are evenly and circumferentially arranged on the outer radial side thereof. In addition, the dynamic pressure generation groove113, the inclined groove113′, and the fluid introduction groove116are formed by reversing the dynamic pressure generation groove13, the inclined groove13′, and the fluid introduction groove16of the first embodiment.

In addition, the arrangement configuration of the dynamic pressure generation groove or the fluid introduction groove of this modified example can be also applied to the sliding surfaces of the sliding components of the following embodiments. That is, the arrangement configuration can be applied to an outside type mechanical seal by replacing the radial arrangement of the dynamic pressure generation grooves or the fluid introduction grooves of the following embodiments.

Second Embodiment

Next, a sliding component according to a second embodiment of the present invention will be described with reference toFIG.7. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.7, a dynamic pressure generation groove213of which an outer radial end213B is disposed between the adjacent fluid introduction grooves16in the circumferential direction in a sliding surface211of a stationary seal ring210of the second embodiment has the same configuration as the dynamic pressure generation groove13of the first embodiment. Further, a dynamic pressure generation groove213′ of which an outer radial end213B′ is disposed on the inner radial side of the fluid introduction groove16includes an inclined groove214′ which extends from the inner radial side toward the outer radial side and generates the dynamic pressure and a reverse inclined groove215′ which is continuously formed on the outer radial side of the inclined groove214′, extends in the reverse direction with respect to the inclined groove214′, and generates the dynamic pressure and is formed in an L shape.

In addition, the extension length of the reverse inclined groove215′ is shorter than the extension length of the inclined groove214′. Further, the extension lengths of the inclined groove214′ and the reverse inclined groove215′ are respectively shorter than the extension lengths of an inclined groove214and a reverse inclined groove215constituting the dynamic pressure generation groove213.

Accordingly, in the normal rotation state, similarly to the dynamic pressure generation groove213, the sealing target fluid F sucked into the dynamic pressure generation groove213′ in the periphery of the reverse inclined groove215′ and the inclined groove214′ also on the inner radial side of the fluid introduction groove16is returned between the sliding surfaces211and21from an acute angle portion213C′ toward the outer radial side and is pushed back toward the outer space S2. Further, in the reverse rotation state, the sealing target fluid F flowing out of an acute angle portion213D′ pushes back the sealing target fluid F in the vicinity of the acute angle portion213D′ toward the outer space S2to enter the Rayleigh step18of the fluid introduction groove16. Therefore, it is possible to suppress the wear by separating the sliding surfaces211and21from each other during both rotations and to further suppress the sealing target fluid F from leaking to the inner space S1from between the sliding surfaces211and21.

Third Embodiment

Next, a sliding component according to a third embodiment of the present invention will be described with reference toFIGS.8to10. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.8, an inclined groove313′ of which an outer radial end313B′ is disposed on the inner radial side of the fluid introduction groove16in a sliding surface311of a stationary seal ring310of the third embodiment has the same configuration as that of the inclined groove13′ of the first embodiment. Further, the dynamic pressure generation groove313includes an inclined groove314which extends from the inner radial side toward the outer radial side and generates the dynamic pressure and a reverse inclined groove315which is a concave portion radially separated on the outer radial side of the inclined groove314, extending in the reverse direction with respect to the inclined groove314, and generating the dynamic pressure. That is, the dynamic pressure generation groove313has a configuration in which the inclined groove314and the reverse inclined groove315are separated in the radial direction by an annular land portion312dto be described later. In addition, the reverse inclined groove315is disposed at a land portion312bbetween the adjacent fluid introduction grooves16in the circumferential direction.

Specifically, the inclined groove314extends in an arc shape while being inclined in the normal rotation direction of the rotating seal ring20from an inner radial end314A toward the outer radial side by allowing the inner radial end314A to communicate with the inner space S1and a linear outer radial end314B of the inclined groove314is closed not to communicate with the reverse inclined groove315.

The reverse inclined groove315has a substantially parallelogram shape and extends in a linear shape while being inclined in the reverse rotation direction of the rotating seal ring20from an inner radial end315A toward the outer radial side and an outer radial end315B is closed not to communicate with the outer space S2.

Further, the annular land portion312dwhich is continuous in the circumferential direction and has a predetermined radial width or more is formed between the inclined groove314and the reverse inclined groove315. In addition, the annular land portion312dis also disposed on the same plane as the other land portion and forms the flat surface of the land312.

Further, the inclined groove314is provided with an acute angle portion314C which is formed by a wall portion314band a side wall portion314dat the outer radial end314B and an obtuse angle portion314D which is formed by the wall portion314band a side wall portion314c.

Further, the reverse inclined groove315is provided with an acute angle portion315C which is formed by a wall portion315band a side wall portion315dat the inner radial end315A and an acute angle portion315D which is formed by a wall portion315eand a side wall portion315cat the linear outer radial end315B and the acute angle portion315D is located on the outer radial side in relation to the acute angle portion315C and the downstream side in the reverse rotation direction of the rotating seal ring20.

Further, the extension length of the reverse inclined groove315is shorter than the extension length of the inclined groove314. Further, the depth of the reverse inclined groove315is the same as the depth of the inclined groove314. In addition, the reverse inclined groove315may be formed to have a depth different from that of the inclined groove314.

Further, the outer radial end314B and the inner radial end315A are arranged at the radially overlapping position to be substantially parallel with substantially the same length. It is preferable that the inner radial end315A is disposed at the radially overlapping position while having a length equal to or larger than the outer radial end314B from the viewpoint of preventing the leakage.

Next, the operation during the relative rotation of the stationary seal ring310and the rotating seal ring20will be described with reference toFIGS.9and10. In addition, since the movement of the fluid at the fluid introduction groove16and the inclined groove313′ is substantially the same as that of the first embodiment, this embodiment will be described by focusing on the movement of the fluid at the inclined groove314and the reverse inclined groove315constituting the dynamic pressure generation groove313.

In the dynamic pressure generation groove313, when the relative rotation speed of the rotating seal ring20and the stationary seal ring310in the normal rotation direction is low, the atmosphere A is not sufficiently dense in the inclined groove314and a high positive pressure is not generated. Further, since the extension length of the reverse inclined groove315is short, a high positive pressure is not generated even when the sealing target fluid F enters the reverse inclined groove315.

When the relative rotation speed of the rotating seal ring20increases, as shown inFIG.9, the atmosphere A in the inclined groove314moves in a following manner in the normal rotation direction of the rotating seal ring20due to shearing with the sliding surface21and the atmosphere A of the inner space S1is drawn into the inclined groove314. That is, a large amount of the atmosphere A moves in the inclined groove314from the inner radial end314A toward the outer radial end314B of the inclined groove314as indicated by the arrow L1.

The pressure of the atmosphere A having moved toward the outer radial end314B of the inclined groove314is increased at the acute angle portion314C and in the vicinity thereof. That is, a positive pressure is generated at the acute angle portion314C and in the vicinity thereof.

Further, since the atmosphere A in the inclined groove314indicated by the arrow L2acts to push back the sealing target fluid F in the vicinity of the acute angle portion314C toward the outer space S2, the amount of the sealing target fluid F leaking into the inclined groove314or the inner space S1is small.

On the other hand, in the reverse inclined groove315, the sealing target fluid F having entered the reverse inclined groove315moves in a following manner in the normal rotation direction of the rotating seal ring20due to shearing with the sliding surface21and the sealing target fluid F in the vicinity of the acute angle portion315D is drawn into the reverse inclined groove315. That is, in the reverse inclined groove315, the sealing target fluid F moves from the acute angle portion315D toward the acute angle portion315C of the reverse inclined groove315as indicated by the arrow H5and the pressure at the acute angle portion315C and in the vicinity thereof is increased. That is, a positive pressure is generated at the acute angle portion315C and in the vicinity thereof.

Further, the sealing target fluid F in the reverse inclined groove315indicated by the arrow H6is pushed back toward the outer space S2by the atmosphere A in the inclined groove314indicated by the arrow L2together with the sealing target fluid F in the vicinity of the acute angle portion315C.

Next, the reverse rotation state of the rotating seal ring20will be described with reference toFIG.10. As shown inFIG.10, the sealing target fluid F having entered the reverse inclined groove315formed on the outer radial side of the inclined groove314moves in a following manner in the reverse rotation direction of the rotating seal ring20due to shearing with the sliding surface21and the sealing target fluid F in the vicinity of the acute angle portion315C is drawn into the reverse inclined groove315. That is, in the reverse inclined groove315, the sealing target fluid F moves from the acute angle portion315C toward the acute angle portion315D of the reverse inclined groove315as indicated by the arrow H3′ and the pressure at the acute angle portion315D and in the vicinity thereof is increased. That is, a positive pressure is generated at the acute angle portion315D and in the vicinity thereof.

Since the sealing target fluid F in the reverse inclined groove315indicated by the arrow H4′ acts to push back the sealing target fluid F in the vicinity of the acute angle portion315D of the reverse inclined groove315toward the outer space S2, the amount of the sealing target fluid F leaking into the inclined groove314or the inner space S1is small.

Further, at this time, the sealing target fluid F existing in the periphery of the acute angle portion315C is sucked into the reverse inclined groove315as indicated by the arrow H5′ due to the negative pressure generated at the acute angle portion315C and in the vicinity thereof. The sealing target fluid F sucked into the reverse inclined groove315is returned between the sliding surfaces311and21from the acute angle portion315D toward the outer radial side.

Further, the sealing target fluid F introduced into the fluid introduction groove16and flowing out between the sliding surfaces311and21from the vicinity of the liquid guide groove portion17is captured by being sucked into the reverse inclined groove315of the dynamic pressure generation groove313located on the downstream side in the relative rotation direction of the liquid guide groove portion17of the fluid introduction groove16. At this time, since a negative pressure is generated at the acute angle portion315C and in the vicinity thereof, the sealing target fluid F having flowed out between the sliding surfaces311and21is easily sucked into the reverse inclined groove315of the dynamic pressure generation groove313.

Further, the sealing target fluid F having returned between the sliding surfaces311and21toward the outer radial side from the acute angle portion315D of the reverse inclined groove315of the dynamic pressure generation groove313located on the upstream side in the relative rotation direction of the Rayleigh step18of the fluid introduction groove16is sucked into the fluid introduction groove16as indicated by the arrow H2′ due to the negative pressure generated at the end portion18A of the Rayleigh step18and in the vicinity thereof as described above.

In this way, since the sealing target fluid F is passed between the fluid introduction groove16and the plurality of reverse inclined grooves315and is retained on the outer radial side in such a manner that the reverse inclined grooves315of the plurality of dynamic pressure generation grooves313are arranged between the adjacent fluid introduction grooves16in the circumferential direction in the reverse rotation state, the amount of the sealing target fluid F leaking into the dynamic pressure generation groove313or the inner space S1is small.

As described above, when the rotating seal ring20rotates in the normal rotation direction, the sealing target fluid F having flowed between the sliding surfaces311and21from the outer space S2is sucked and pushed back toward the outer space S2due to the positive pressure generated in each of the reverse inclined groove315and the inclined groove314of the dynamic pressure generation groove313. Accordingly, it is possible to suppress the sealing target fluid F from leaking to the inner space S1from between the sliding surfaces311and21. On the other hand, when the rotating seal ring20rotates in the reverse rotation direction, the sealing target fluid F having entered the reverse inclined groove315on the outer radial side of the inclined groove314moves in a following manner due to shearing with the sliding surface21of the rotating seal ring20and is returned between the sliding surfaces311and21from the end portion on the side of the sealing target fluid F of the reverse inclined groove315, that is, the acute angle portion315D toward the outer radial side. Accordingly, it is possible to reduce the leakage of the sealing target fluid F to the inner space S1. In this way, since the dynamic pressure generation groove313includes the inclined groove314and the reverse inclined groove315having different rotation directions for generating the main dynamic pressure, it is possible to suppress the wear by separating the sliding surfaces311and21during both rotations and to suppress the sealing target fluid F from leaking to the inner space S1from between the sliding surfaces311and21.

Further, in the reverse rotation state, the sealing target fluid F introduced into the fluid introduction groove16and flowing out between the sliding surfaces311and21from the vicinity of the liquid guide groove portion17is captured by being sucked into the reverse inclined groove315of the dynamic pressure generation groove313located on the downstream side in the relative rotation direction of the liquid guide groove portion17of the fluid introduction groove16. At this time, since a negative pressure is generated at the acute angle portion315C and in the vicinity thereof, the sealing target fluid F having flowed out between the sliding surfaces311and21is easily sucked into the reverse inclined groove315of the dynamic pressure generation groove313. Further, since the sealing target fluid F captured in the reverse inclined groove315moves in a following manner due to shearing with the sliding surface21of the rotating seal ring20and is returned between the sliding surfaces311and21from the acute angle portion315D of the reverse inclined groove315toward the outer radial side, it is possible to further reduce the leakage of the sealing target fluid F to the inner space S1.

Further, since the annular land portion312dwhich is continuous in the circumferential direction and has a predetermined radial width or more is formed between the inclined groove314and the reverse inclined groove315and the inclined groove314and the reverse inclined groove315are separated from each other by the annular land portion312d, the sealing target fluid F is captured by being sucked into the reverse inclined groove315from the acute angle portion315C on the outer radial side of the annular land portion312din the reverse rotation state of the rotating seal ring20. Accordingly, it is possible to suppress the sealing target fluid F from entering the inclined groove314over the annular land portion312dand to further reduce the sealing target fluid F leaking to the inner space S1through the inclined groove314.

Further, since the inclined groove314and the reverse inclined groove315are separated from each other by the annular land portion312d, the inclined groove314and the reverse inclined groove315do not interfere with each other in the generation of the dynamic pressure during both rotations. Accordingly, it is easy to exhibit the dynamic pressure effect.

Further, the radial center of the annular land portion312dseparating the inclined groove314and the reverse inclined groove315from each other is disposed closer to the sealing target fluid F than the radial center of the sliding surface311. Accordingly, since the long extension length of the inclined groove314can be ensured and the inclined groove314serves as a main dynamic pressure generation source compared to the reverse inclined groove315in the normal rotation state, it is possible to further suppress the sealing target fluid F from leaking to the inner space S1.

In addition, the inclined groove313′ is not limited to the same configuration as that of the inclined groove13′ of the first embodiment and may have, for example, the same configuration as the dynamic pressure generation groove213′ of the second embodiment. Similarly to the dynamic pressure generation groove313, the inclined groove and the reverse inclined groove may be separated from each other in the radial direction. Further, the modified configuration of the dynamic pressure generation groove can be also applied to the sliding surfaces of the sliding components of the following embodiments.

Fourth Embodiment

Next, a sliding component according to a fourth embodiment of the present invention will be described with reference toFIG.11. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.11, in a sliding surface411of a stationary seal ring410of the fourth embodiment, a dynamic pressure generation groove413includes an inclined groove414which extends from the inner radial side toward the outer radial side and generates the dynamic pressure and a concave portion415which is radially separated on the outer radial side of the inclined groove414.

The concave portion415has a substantially square shape and is disposed at the substantially circumferential center of an outer radial end414B of the inclined groove414in a land portion412bbetween the adjacent fluid introduction grooves16in the circumferential direction. In the concave portion415, corner portions facing each other in the radial direction, that is, diagonal lines are arranged on the radial line of the stationary seal ring410.

Accordingly, since the sealing target fluid F flowing out between the sliding surfaces411and21from the fluid introduction groove16is captured by the concave portion415on the downstream side in the relative rotation direction of the fluid introduction groove16in the reverse rotation state, it is possible to reduce the leakage of the sealing target fluid F to the inner space S1.

In addition, similarly to the reverse inclined groove315of the third embodiment, the concave portion415is not limited to a substantially square shape unless there is directionality in the circumferential direction extending from upstream to downstream during relative rotation. For example, the concave portion may be freely formed in other shapes such as a circular shape or a triangular shape.

Fifth Embodiment

Next, a sliding component according to a fifth embodiment of the present invention will be described with reference toFIG.12. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.12, a fluid introduction groove516of a stationary seal ring510of the fifth embodiment includes a liquid guide groove portion517which communicates with the outer space S2and Rayleigh steps518and518′ which respectively extend in the circumferential direction concentrically with the stationary seal ring510from the inner radial side of the liquid guide groove portion517toward the normal rotation direction and the reverse rotation direction of the rotating seal ring20.

Accordingly, in the normal rotation state of the rotating seal ring20, the sealing target fluid F in the fluid introduction groove516moves in a following manner in the normal rotation direction of the rotating seal ring20due to shearing with the sliding surface21to move from the liquid guide groove portion517toward the Rayleigh step518and the sealing target fluid F of the outer space S2is drawn into the liquid guide groove portion517. Further, even in the reverse rotation state, the sealing target fluid F in the fluid introduction groove516moves in a following manner in the reverse rotation direction of the rotating seal ring20due to shearing with the sliding surface21to move from the liquid guide groove portion517toward the Rayleigh step518′ and the sealing target fluid F of the outer space S2is drawn into the liquid guide groove portion517.

In this way, since the fluid introduction groove516generate the dynamic pressure by the Rayleigh steps518and518′ during both rotations so that the sliding surfaces511and21are slightly separated from each other and the sealing target fluid F can be supplied between the sliding surfaces511and21, it is possible to improve the lubricity between the sliding surfaces511and21.

Sixth Embodiment

Next, a sliding component according to a sixth embodiment of the present invention will be described with reference toFIG.13. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.13, a fluid introduction groove616of a stationary seal ring610of the sixth embodiment has the same configuration as that of the fluid introduction groove516of the fifth embodiment. Further, a dynamic pressure generation groove613has the same configuration as that of the dynamic pressure generation groove313of the third embodiment.

Accordingly, since the fluid introduction groove616slightly separates the sliding surfaces611and21from each other during both rotations so that the sealing target fluid F is introduced between the sliding surfaces611and21, it is possible to further suppress the wear between the sliding surfaces611and21and to suppress the leakage of the sealing target fluid F by the inclined groove614and the reverse inclined groove615separated in the radial direction in the dynamic pressure generation groove613.

Seventh Embodiment

Next, a sliding component according to a seventh embodiment of the present invention will be described with reference toFIG.14. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.14, a fluid introduction groove716of a stationary seal ring710of the seventh embodiment is formed as a substantially trapezoidal groove communicating with the outer space S2.

Specifically, in the fluid introduction groove716, a side wall portion716aon the downstream side in the normal rotation direction of the rotating seal ring20extends in a linear shape while being inclined toward the reverse rotation direction from the outer radial side toward the inner radial side and a side wall portion716don the upstream side in the normal rotation direction of the rotating seal ring20extends in a linear shape along a radial line from the outer radial side toward the inner radial side. Further, in the fluid introduction groove716, an acute angle portion716A which is formed by a side wall portion716band a wall portion716cat the inner radial end is disposed to be circumferentially adjacent to an acute angle portion713C of the dynamic pressure generation groove713on the downstream side in the normal rotation direction.

Accordingly, since the side wall portion716aof the fluid introduction groove716is inclined along the circumferential direction, the sealing target fluid F is likely to be introduced into the fluid introduction groove716when the relative rotation of the stationary seal ring710and the rotating seal ring20starts in the normal rotation state of the rotating seal ring20.

Further, since the acute angle portion716A of the fluid introduction groove716is disposed to be circumferentially adjacent to the acute angle portion713C of the dynamic pressure generation groove713, the sealing target fluid F intensively leaking to the acute angle portion716A of the fluid introduction groove716in the reverse rotation state of the rotating seal ring20can be sucked and collected by the negative pressure generated at the acute angle portion713C of the dynamic pressure generation groove713and in the vicinity thereof. Accordingly, it is possible to further suppress the sealing target fluid F from leaking to the inner space S1.

Eighth Embodiment

Next, a sliding component according to an eighth embodiment of the present invention will be described with reference toFIG.15. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.15, a fluid introduction groove816of a stationary seal ring810of the eighth embodiment is formed as a square groove communicating with the outer space S2.

Specifically, the fluid introduction groove816extends in a linear shape while being inclined toward the reverse rotation direction from the outer radial side toward the inner radial side of a side wall portion816aon the downstream side in the normal rotation direction of the rotating seal ring20and a side wall portion816bon the upstream side in the normal rotation direction thereof. Further, in the fluid introduction groove816, an acute angle portion816A which is formed by a side wall portion816band a wall portion816cat the inner radial end is disposed to be circumferentially adjacent to an acute angle portion813C of the dynamic pressure generation groove813on the downstream side in the normal rotation direction.

Accordingly, since each of the side wall portions816aand816bof the fluid introduction groove816is inclined along the circumferential direction, the sealing target fluid F is more likely to be introduced into the fluid introduction groove816when the relative rotation of the stationary seal ring810and the rotating seal ring20starts in the normal rotation state of the rotating seal ring20.

Further, in the fluid introduction groove816, since the acute angle portion816A has an angle smaller than that of the seventh embodiment and is adjacent to the acute angle portion813C of the dynamic pressure generation groove813in the circumferential direction, the sealing target fluid F is likely to concentrate on the acute angle portion816A and the sealing target fluid F intensively leaking to the acute angle portion816A of the fluid introduction groove816can be sucked and collected by the negative pressure generated at the acute angle portion813C of the dynamic pressure generation groove813and in the vicinity thereof in the reverse rotation state of the rotating seal ring20. Accordingly, it is possible to further suppress the sealing target fluid F from leaking to the inner space S1.

Ninth Embodiment

Next, a sliding component according to a ninth embodiment of the present invention will be described with reference toFIG.16. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.16, a fluid introduction groove916of a stationary seal ring910of the ninth embodiment includes a liquid guide groove portion917which communicates with the outer space S2and a Rayleigh step918which extends in the circumferential direction concentrically with the stationary seal ring910from the outer radial side of the liquid guide groove portion917toward the normal rotation direction of the rotating seal ring20. In addition, the liquid guide groove portion917has substantially the same shape as that of the fluid introduction groove916of the eighth embodiment.

Accordingly, since the fluid introduction groove916includes the Rayleigh step918, it is possible to improve the lubricity between the sliding surfaces911and21in such a manner that the Rayleigh step918generates the dynamic pressure in the normal rotation state so that the sliding surfaces911and21are slightly separated from each other and the sealing target fluid F is supplied between the sliding surfaces911and21.

Tenth Embodiment

Next, a sliding component according to a tenth embodiment of the present invention will be described with reference toFIG.17. In addition, the description of the configuration that is the same as that of the above-described embodiment and is duplicated will be omitted.

As shown inFIG.17, a fluid introduction groove1016of a stationary seal ring1010of the tenth embodiment includes a liquid guide groove portion1017which communicates with the outer space S2and Rayleigh steps1018and1018′ which respectively extend in the circumferential direction concentrically with the stationary seal ring1010from the inner radial side of the liquid guide groove portion1017toward the normal rotation direction and the reverse rotation direction of the rotating seal ring20. In addition, the liquid guide groove portion1017has substantially the same shape as that of the fluid introduction groove816of the eighth embodiment.

Accordingly, since the dynamic pressure is generated by the Rayleigh steps1018and1018′ during both rotations so that the sliding surfaces1011and21are slightly separated from each other and the sealing target fluid F is supplied between the sliding surfaces1011and21, it is possible to improve the lubricity between the sliding surfaces1011and21.

Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments and is included in the present invention even if there are changes or additions within the scope of the present invention.

For example, in the above-described embodiments, as the sliding component, the mechanical seal for automobiles has been described as an example, but other mechanical seals for general industrial machines may be used. Further, the present invention is not limited to the mechanical seal and may be a sliding component other than the mechanical seal such as a slide bearing.

Further, in the above-described embodiments, an example in which the dynamic pressure generation groove and the fluid introduction groove are provided in the stationary seal ring has been described, but the dynamic pressure generation groove and the fluid introduction groove may be provided in the rotating seal ring.

Further, the sealing target fluid side has been described as the high-pressure side and the leakage side has been described as the low-pressure side. However, the sealing target fluid side may be the low-pressure side, the leakage side may be the high pressure side, and the sealing target fluid side and the leakage side may have substantially the same pressure.

Further, it has been described that the inclined groove in the dynamic pressure generation groove communicates with the inner space S1, but the present invention is not limited thereto. If the dynamic pressure can be generated, the inclined groove may not communicate with the inner space.

Further, the dynamic pressure generation groove is not limited to the one in which the reverse inclined groove is continuously formed at the outer radial end portion of the inclined groove and the reverse inclined groove may be formed by branching from substantially the center portion of the inclined groove in the extension direction.

Further, in the dynamic pressure generation groove, the plurality of reverse inclined grooves may be arranged for one inclined groove.

Further, the inclined groove is not limited to the one extending in the circular shape while being inclined in the circumferential direction and the shape may be simplified by the linear shape.

Further, it has been described that the dynamic pressure generation groove and the fluid introduction groove have substantially the same depth, but the fluid introduction groove may be deeper than the dynamic pressure generation groove.

Further, in this embodiment, the sealing target fluid F has been described as the high-pressure liquid, but the present invention is not limited thereto. For example, the sealing target fluid may be a gas or a low-pressure liquid or may be a mist in which a liquid and a gas are mixed.

Further, in this embodiment, the leakage side fluid has been described as the atmosphere A corresponding to the low-pressure gas, but the present invention is not limited thereto. For example, the leakage side fluid may be a liquid or a high-pressure gas or may be a mist in which a liquid and a gas are mixed.

REFERENCE SIGNS LIST

10Stationary seal ring (sliding component)11Sliding surface12Land12ato12cLand portion13Dynamic pressure generation groove13′ Inclined groove13C,13C′,13D Acute angle portion14Inclined groove15Reverse inclined groove (concave portion)16Fluid introduction groove17Liquid guide groove portion18Rayleigh step20Rotating seal ring (different component)21Sliding surface310Stationary seal ring (sliding component)311Sliding surface312dAnnular land portion313Dynamic pressure generation groove313′ Inclined groove314Inclined groove314C Acute angle portion315Reverse inclined groove (concave portion)315C,315D Acute angle portion410Stationary seal ring (sliding component)411Sliding surface413Dynamic pressure generation groove414Inclined groove415Concave portionA AtmosphereF Sealing target fluidS1Inner spaceS2Outer space