Sliding parts
A positive pressure generation mechanism includes a positive pressure generation groove provided on a high pressure side of one of sealing faces of a pair of sliding parts including annular bodies that relatively slide on each other, a negative pressure generation mechanism including a negative pressure generation groove provided on a low pressure side, a pressure release groove provided between the positive pressure generation groove and the negative pressure generation groove, and a radial groove that provides communication between the positive pressure generation groove.
1. A pair of sliding parts comprising annular bodies, in which
a positive pressure generation mechanism including a positive pressure generation groove is provided on a high pressure side of one of sealing faces that relatively slide on each other,
a negative pressure generation mechanism including a negative pressure generation groove is provided on a low pressure side,
a pressure release groove is provided between the positive pressure generation groove and the negative pressure generation groove, and further, a radial groove that provides communication between the positive pressure generation groove, the pressure release groove and the negative pressure generation groove, and a high pressure fluid side is provided on the sealing face, and
the positive pressure generation groove, the pressure release groove, the negative pressure generation groove, and the radial groove are isolated from a low pressure fluid side by a seal face,
wherein:
the radial groove includes an inlet section that provides communication between an upstream side of the positive pressure generation groove and the pressure release groove, and the high pressure fluid side, and an outlet section that provides communication between a downstream side of the negative pressure generation groove and the pressure release groove, and the high pressure fluid side;
the inlet section and the outlet section are inclined in the directions in which the sections respectively open from the low pressure side toward the high pressure side; and
an intersection angle of both the sections made by a tangent line on a sealing face end is set to be an obtuse angle.
2. The sliding parts according to claim 1 , wherein:
the positive pressure generation mechanism on the high pressure side is formed from a Rayleigh step mechanism;
the negative pressure generation mechanism on the low pressure side is formed from a reversed Rayleigh step mechanism;
the pressure release groove is formed from a circumferential groove;
plural pairs of the Rayleigh step mechanisms and the reversed Rayleigh step mechanisms are provided in such a manner that each of the pairs is set in parallel in the circumferential direction across the pressure release groove;
the Rayleigh step is also provided between the outlet section on the upstream side and the adjacent inlet section on the downstream side; and
the reversed Rayleigh step mechanism is extended over the adjacent outlet sections.
3. The sliding parts according to claim 1 , wherein:
the outlet section is formed in a spiral shape from the low pressure side to the high pressure side.
4. The sliding parts according to claim 3 , wherein:
a part of the outlet section that communicates with the negative pressure generation groove is formed to be equal to or deeper than the positive pressure generation groove or the negative pressure generation groove and shallower than the other parts of the radial groove.
5. The sliding parts according to claim 4 , wherein:
the positive pressure generation mechanism on the high pressure side is formed from a Rayleigh step mechanism;
the negative pressure generation mechanism on the low pressure side is formed from a reversed Rayleigh step mechanism;
the pressure release groove is formed from a circumferential groove;
plural pairs of the Rayleigh step mechanisms and the reversed Rayleigh step mechanisms are provided in such a manner that each of the pairs is set in parallel in the circumferential direction across the pressure release groove;
the Rayleigh step is also provided between the outlet section on the upstream side and the adjacent inlet section on the downstream side; and
the reversed Rayleigh step mechanism is extended over the adjacent outlet sections.
6. The sliding parts according to claim 3 , wherein:
the positive pressure generation mechanism on the high pressure side is formed from a Rayleigh step mechanism;
the negative pressure generation mechanism on the low pressure side is formed from a reversed Rayleigh step mechanism;
the pressure release groove is formed from a circumferential groove;
plural pairs of the Rayleigh step mechanisms and the reversed Rayleigh step mechanisms are provided in such a manner that each of the pairs is set in parallel in the circumferential direction across the pressure release groove;
the Rayleigh step is also provided between the outlet section on the upstream side and the adjacent inlet section on the downstream side; and
the reversed Rayleigh step mechanism is extended over the adjacent outlet sections.
7. The sliding parts according to claim 6 , wherein:
the positive pressure generation mechanism on the high pressure side is formed from a Rayleigh step mechanism;
the negative pressure generation mechanism on the low pressure side is formed from a reversed Rayleigh step mechanism;
the pressure release groove is formed from a circumferential groove;
plural pairs of the Rayleigh step mechanisms and the reversed Rayleigh step mechanisms are provided in such a manner that each of the pairs is set in parallel in the circumferential direction across the pressure release groove;
the Rayleigh step is also provided between the outlet section on the upstream side and the adjacent inlet section on the downstream side; and
the reversed Rayleigh step mechanism is extended over the adjacent outlet sections.
8. The sliding parts according to claim 1 , wherein:
a part of the outlet section that communicates with the negative pressure generation groove is formed to be equal to or deeper than the positive pressure generation groove or the negative pressure generation groove and shallower than the other parts of the radial groove.
9. The sliding parts according to claim 8 , wherein:
the positive pressure generation mechanism on the high pressure side is formed from a Rayleigh step mechanism;
the negative pressure generation mechanism on the low pressure side is formed from a reversed Rayleigh step mechanism;
the pressure release groove is formed from a circumferential groove;
plural pairs of the Rayleigh step mechanisms and the reversed Rayleigh step mechanisms are provided in such a manner that each of the pairs is set in parallel in the circumferential direction across the pressure release groove;
the Rayleigh step is also provided between the outlet section on the upstream side and the adjacent inlet section on the downstream side; and
the reversed Rayleigh step mechanism is extended over the adjacent outlet sections.