Sliding component

1. A sliding component comprising

a positive pressure generating mechanism comprising a positive pressure generating groove provided to a high-pressure side of one of two sliding surfaces that slide relative to each other in a pair of sliding components, and

a negative pressure generating mechanism comprising a negative pressure generating groove provided to a low-pressure side, said positive pressure generating groove and negative pressure generating groove being communicated with a high-pressure fluid side and separated from a low-pressure fluid side by a seal surface,

wherein the external-peripheral-side positive pressure generating mechanism is formed from a Rayleigh step mechanism, and the internal-peripheral-side negative pressure generating mechanism is formed from a reverse Rayleigh step mechanism, said Rayleigh step mechanism and reverse Rayleigh step mechanism being communicated with the high-pressure fluid side, and

wherein pluralities of Rayleigh step mechanisms and reverse Rayleigh step mechanisms are provided in parallel in a circumferential direction so as to constitute pairs, and an upstream end of a groove part of an n th Rayleigh step mechanism and a downstream end of a groove part of an n−1 th reverse Rayleigh step mechanism are formed so as to substantially coincide in a position in the circumferential direction as seen from the upstream side, both groove parts being communicated with the high-pressure fluid side via a shared communication.

2. A sliding component according to claim 1 , wherein said negative pressure generating groove is provided to a low-pressure side of the other sliding surface.

3. The sliding component according to claim 2 , wherein the width of the internal-peripheral-side seal surface can be varied.

4. The sliding component according to claim 1 , wherein the width of the internal-peripheral-side seal surface can be varied.

5. The sliding component according to claim 1 , wherein a radial-direction groove is shaped so as to be slanted from the internal peripheral side communicated with the negative pressure generating mechanism to the external peripheral side in the rotational direction of the counterpart sliding surface.

6. A sliding component comprising an external peripheral side of a pair of sliding components having a high-pressure fluid side and an internal peripheral side having a low-pressure fluid side,

a positive pressure generating mechanism comprising a positive pressure generating groove provided to a high-pressure side of a sliding surface of a stationary-side sliding component, and

a negative pressure generating mechanism comprising a negative pressure generating groove provided to a low-pressure side of a sliding surface of a rotating-side sliding component, said positive pressure generating groove and negative pressure generating groove being communicated with the high-pressure fluid side and separated from the low-pressure fluid side by an internal-peripheral-side seal surface,

wherein the external-peripheral-side positive pressure generating mechanism is formed from a Rayleigh step mechanism, and the internal-peripheral-side negative pressure generating mechanism is formed from a reverse Rayleigh step mechanism, said Rayleigh step mechanism and reverse Rayleigh step mechanism being communicated with the high-pressure fluid side, and wherein

wherein pluralities of Rayleigh step mechanisms and reverse Rayleigh step mechanisms are provided in parallel in a circumferential direction so as to constitute pairs, and an upstream end of a groove part of an n th Rayleigh step mechanism and a downstream end of a groove part of an n−1 th reverse Rayleigh step mechanism are formed so as to substantially coincide in a position in the circumferential direction as seen from the upstream side, both groove parts being communicated with the high-pressure fluid side via a shared communication.

7. The sliding component according to claim 6 , wherein the width of the internal-peripheral-side seal surface can be varied.

8. The sliding component according to claim 6 , wherein a radial-direction groove is shaped so as to be slanted from the internal peripheral side communicated with the negative pressure generating mechanism to the external peripheral side in the rotational direction of the counterpart sliding surface.

9. A sliding component comprising a pair of sliding components comprising annular bodies,

an external peripheral side of said annular bodies having a high-pressure fluid side and an internal peripheral side having a low-pressure fluid side, in a sliding surface on one side of the annular body,

a positive pressure generating mechanism comprising a positive pressure generating groove provided to the external peripheral side, and a negative pressure generating mechanism comprising a negative pressure generating groove provided to the internal peripheral side, said positive pressure generating groove and negative pressure generating groove being communicated with the high-pressure fluid side, and separated from the low-pressure fluid side by an internal-peripheral-side seal surface,

wherein the external-peripheral-side positive pressure generating mechanism is formed from a Rayleigh step mechanism, and the internal-peripheral-side negative pressure generating mechanism is formed from a reverse Rayleigh step mechanism, said Rayleigh step mechanism and reverse Rayleigh step mechanism being communicated with the high-pressure fluid side, and

wherein pluralities of Rayleigh step mechanisms and reverse Rayleigh step mechanisms are provided in parallel in a circumferential direction so as to constitute pairs, and an upstream end of a groove part of an n th Rayleigh step mechanism and a downstream end of a groove part of an n−1 th reverse Rayleigh step mechanism are formed so as to substantially coincide in a position in the circumferential direction as seen from the upstream side, both groove parts being communicated with the high-pressure fluid side via a shared communication.

10. The sliding component according to claim 9 , wherein the width of the internal-peripheral-side seal surface can be varied.

11. The sliding component according to claim 9 , wherein a radial-direction groove is shaped so as to be slanted from the internal peripheral side communicated with the negative pressure generating mechanism to the external peripheral side in the rotational direction of the counterpart sliding surface.

12. A sliding component comprising an external peripheral side of a pair of sliding components having a high-pressure fluid side and an internal peripheral side having a low-pressure fluid side,

a positive pressure generating mechanism comprising a positive pressure generating groove provided to a high-pressure side of a sliding surface of a stationary-side sliding component, and

a negative pressure generating mechanism comprising a negative pressure generating groove provided to a low-pressure side of a sliding surface of a rotating-side sliding component, said positive pressure generating groove and negative pressure generating groove being communicated with the high-pressure fluid side and separated from the low-pressure fluid side by an internal-peripheral-side seal surface,

wherein the external-peripheral-side positive pressure generating mechanism is formed from a Rayleigh step mechanism, and the internal-peripheral-side negative pressure generating mechanism is formed from a reverse Rayleigh step mechanism, said Rayleigh step mechanism and reverse Rayleigh step mechanism being communicated with the high-pressure fluid side, and

wherein a plurality of Rayleigh step mechanisms and one reverse Rayleigh step mechanism are provided in parallel in a circumferential direction, an upstream end of a groove part of one of the Rayleigh step mechanisms and a downstream end of a groove part of the reverse Rayleigh step mechanism are formed so as to substantially coincide in a position in the circumferential direction, and both groove parts are communicated with the high-pressure fluid side via a shared communication, the upstream ends of the groove parts of the remaining Rayleigh step mechanisms being individually communicated with the high-pressure fluid side.

13. The sliding component according to claim 12 , wherein the width of the internal-peripheral-side seal surface can be varied.

14. The sliding component according to claim 12 , wherein a radial-direction groove is shaped so as to be slanted from the internal peripheral side communicated with the negative pressure generating mechanism to the external peripheral side in the rotational direction of the counterpart sliding surface.

15. A sliding component comprising a pair of sliding components comprising annular bodies,

an external peripheral side of said annular bodies having a high-pressure fluid side and an internal peripheral side having a low-pressure fluid side; in a sliding surface on one side of the annular body,

a positive pressure generating mechanism comprising a positive pressure generating groove provided to the external peripheral side, and a negative pressure generating mechanism comprising a negative pressure generating groove provided to the internal peripheral side, said positive pressure generating groove and negative pressure generating groove being communicated with the high-pressure fluid side, and separated from the low-pressure fluid side by an internal-peripheral-side seal surface,

wherein the external-peripheral-side positive pressure generating mechanism is formed from a Rayleigh step mechanism, and the internal-peripheral-side negative pressure generating mechanism is formed from a reverse Rayleigh step mechanism, said Rayleigh step mechanism and reverse Rayleigh step mechanism being communicated with the high-pressure fluid side, and

wherein a plurality of Rayleigh step mechanisms and one reverse Rayleigh step mechanism are provided in parallel in a circumferential direction, an upstream end of a groove part of one of the Rayleigh step mechanisms and a downstream end of a groove part of the reverse Rayleigh step mechanism are formed so as to substantially coincide in a position in the circumferential direction, and both groove parts are communicated with the high-pressure fluid side via a shared communication, the upstream ends of the groove parts of the remaining Rayleigh step mechanisms being individually communicated with the high-pressure fluid side.

16. The sliding component according to claim 15 , wherein the width of the internal-peripheral-side seal surface can be varied.

17. The sliding component according to claim 15 , wherein a radial-direction groove is shaped so as to be slanted from the internal peripheral side communicated with the negative pressure generating mechanism to the external peripheral side in the rotational direction of the counterpart sliding surface.