Sliding component

1. A sliding component comprising a stationary sliding member and a rotary sliding member forming a pair of sliding faces, and a mechanism to generate dynamic pressure resulting from relative sliding of the pair of sealing faces, wherein both sealing faces are flat, one sealing face being provided with a plurality of lands for generating dynamic pressure facing a high-pressure fluid side and a seal area facing a low-pressure fluid side,

wherein the lands are provided at multiple locations at an equal pitch in a circumferential direction each land and seal area are positioned away from each other in a radial direction, and areas of the sealing faces other than the lands and seal area are formed lower than these areas to constitute fluid communication paths,

wherein the fluid communication paths are constituted by (i) multiple radial fluid communication paths, each and every radial fluid communication path extending in the radial direction and being formed between two adjacent lands and defined by the radially extending sidewalls of the adjacent lands, and (ii) an annular fluid communication path extending in a circumferential direction and formed between the seal area and the lands,

wherein the annular fluid communication path is defined, on the low pressure fluid side, by a continuous side wall having a convexly curved smooth arc shape and, on the high pressure fluid side, by a plurality of discontinuous side walls each having a convexly curved smooth arc shape, an arc of the continuous side wall being larger than an arc of each of the discontinuous side walls,

wherein all of the multiple radial fluid communication paths communicate with one another via the annular fluid communication path along the smooth arcs and are open to the high-pressure fluid side, and

wherein a width of each land in the circumferential direction and widths of each fluid communication path in the radial and circumferential directions are set to optimize lubrication of the sealing faces, and to discharge impurities toward the high-pressure side.

2. A sliding component according to claim 1 , wherein one sealing face is given hydrophilizing treatment.

3. A sliding component according to claim 1 , wherein the multiple radial fluid communication paths and the annular fluid communication path are set 10 nm to 1 μm lower than the seal area.

4. A sliding component according to claim 1 , wherein the sliding faces are lapped or finished to a mirror surface.

5. A sliding component according to claim 1 , wherein the widths of the multiple radial fluid communication paths and the annular fluid communication path are equal to or smaller than a width of each land in the circumferential direction.

6. A sliding component comprising a stationary sliding member and a rotary sliding member forming a pair of sliding faces, and a mechanism to generate dynamic pressure resulting from relative sliding of the pair of sealing faces, wherein both of the sealing faces are flat, one sealing face being provided with a plurality of lands for generating dynamic pressure facing a high-pressure fluid side and a seal area facing a low-pressure fluid side, wherein the lands are provided at multiple locations at an equal pitch in a circumferential direction, each land and seal area are positioned away from each other in a radial direction, and areas of the sealing faces other than the lands and seal area are formed lower than these areas to constitute fluid communication paths,

wherein each land has a generally U-shaped profile including radially extending side walls joined at-a curved smooth arc end positioned in such a way that the curved smooth arc end faces the seal area, and the end opposite the curved, smooth arc end faces the high-pressure fluid side,

wherein both the stationary sliding member and the rotary sliding member are rigid, a contact pattern of the pair of sealing faces including a plurality of profiles that are identical with the generally U-shaped profiles of the lands of the one sealing face,

wherein the fluid communication paths are constituted by (i) multiple radial fluid communication paths, each and every radial fluid communication path extending in the radial direction and being formed between two adjacent lands and defined by the radially extending sidewalls of the adjacent lands, and (ii) an annular fluid communication path extending in a circumferential direction and formed between the seal area and the lands, wherein all of the multiple radial fluid communication paths communicate with one another via the annular fluid communication path along the smooth arcs and are open to the high-pressure fluid side, and

wherein a width of each land in the circumferential direction and widths of each fluid communication paths in the radial and circumferential directions are set to optimize lubrication of the sealing faces, and to discharge impurities toward the high-pressure side.

7. A sliding component according to claim 6 , wherein one sealing face is given hydrophilizing treatment.

8. A sliding component according to claim 6 , wherein the multiple radial fluid communication paths and the annular fluid communication path are set 10 nm to 1 μm lower than the seal area.

9. A sliding component according to claim 6 , wherein the sliding faces are lapped or finished to a mirror surface.

10. A sliding component according to claim 6 , wherein the widths of the multiple radial fluid communication path and the annular fluid communication path are equal to or smaller than a width of each land in the circumferential direction.