Sliding component
A sliding component is characterized in that, on one sealing face of a pair of sliding parts that slide relative to each other, multiple positive pressure-generating mechanisms that include extremely shallow parallel grooves running roughly in parallel with the sealing face and having a submicron-level height difference are provided independently in the circumferential direction, and that the extremely shallow parallel grooves connect to the high-pressure fluid side, but are isolated from the low-pressure fluid side by a seal area. The sliding component can reduce a leakage rate of sealed fluid and significantly improve lubrication characteristics at startup or stop, while being actuated by means of fluid lubrication in a rotation phase, thereby achieving the effects of sealing and lubrication at the same time.
1. A sliding component comprising a pair of sliding parts constituted by ring shaped bodies and having sealing faces relatively slidable to each other, wherein:
on one of the sealing faces of the pair of sliding parts, a positive pressure-generating mechanism that comprises multiples of extremely shallow parallel grooves having bottoms with a submicron-level depth, the bottom of the grooves running roughly in parallel with the sealing face, said multiples of extremely shallow parallel grooves being aligned in a circumferential direction in such a way to be separated from and not connected to each other by a seal area, wherein
each extremely shallow parallel groove is a recess that is recessed from the seal area and that is defined by:
a bottom surface having a roughly oval shape,
two straight side walls facing each other in the circumferential direction in such a way to widen a distance therebetween toward a low pressure fluid side and slightly curved toward each other at the low pressure fluid side, and
one low-pressure fluid curved side wall smoothly connecting the two curved side walls,
wherein the recess opens at one peripheral surface of the sliding part on a high-pressure fluid side and directly communicates with the high pressure fluid side, said bottom surface having an arc-shaped apex protruded toward the low-pressure fluid side, and
wherein the extremely shallow parallel grooves are isolated from the low-pressure fluid side by the seal area.
2. A sliding component according to claim 1 , wherein the extremely shallow parallel grooves have a depth h of 10 nm to 1 μm and roughness α of 1 to 100 nm at a bottom of the groove, and satisfy a relationship of h>α.
3. A sliding component according to claim 2 , wherein preferably the extremely shallow parallel grooves have a depth h of 50 to 500 nm and roughness α of 1 to 30 nm at a bottom of the groove, where a relationship of h>α is satisfied.
4. A sliding component according to claim 1 , wherein the extremely shallow parallel grooves are formed by multiple grooves of different depths.
5. A sliding component according to claim 1 , wherein preferably the extremely shallow parallel grooves are provided to account for 5 to 70% of an area of the sealing face.
6. A sliding component according to claim 1 , wherein the pair of sliding parts is comprised of ring-shaped bodies each used as either a stationary-side sliding member or rotating-side sliding member of a mechanical seal that rotates relative to the other member.
7. A sliding component according to claim 2 , wherein the extremely shallow parallel grooves are formed by multiple grooves of different depths.
8. A sliding component according to claim 2 , wherein the extremely shallow parallel grooves account for 5 to 70% of an area of the sealing face.
9. A sliding component according to claim 2 , wherein the pair of sliding parts is comprised of ring-shaped bodies each used as either a stationary-side sliding member or a rotating-side sliding member of a mechanical seal that rotates relative to the other member.
10. A sliding component according to claim 3 , wherein the extremely shallow parallel grooves are formed by multiple grooves of different depths.
11. A sliding component according to claim 3 , wherein characterized in that preferably the extremely shallow parallel grooves account for 5 to 70% of an area of the sealing face.
12. A sliding component according to claim 3 , wherein the pair of sliding parts is comprised of ring-shaped bodies each used as either a stationary-side sliding member or a rotating-side sliding member of a mechanical seal that rotates relative to the other member.
13. A sliding component according to claim 4 , wherein the extremely shallow parallel grooves account for 5 to 70% of an area of the sealing face.
14. A sliding component according to claim 4 , wherein the pair of sliding parts is comprised of ring-shaped bodies each used as either a stationary-side sliding member or a rotating-side sliding member of a mechanical seal that rotates relative to the other member.
15. A sliding component according to claim 5 , wherein the pair of sliding parts is comprised of ring-shaped bodies each used as either a stationary-side sliding member or a rotating-side sliding member of a mechanical seal that rotates relative to the other member.