Seal ring

1. A seal ring for sealing a clearance between a rotary shaft and housing, comprising:

multiple static pressure grooves provided at a sliding surface of the seal ring and arranged in a circumferential direction, the static pressure grooves being opened on a sealed fluid side and closed on an outer diameter side, a circumferential length of each of the static pressure grooves being shorter than a radial length of each of the static pressure grooves;

multiple communication grooves each extending in the circumferential direction on the outer diameter side, each of the communication grooves respectively being in communication with two of the static pressure grooves adjoining each other in the circumferential direction; and

multiple dynamic pressure grooves each opened on the sealed fluid side, each of the dynamic pressure groove respectively being provided between two of the static pressure grooves adjoining each other in the circumferential direction,

wherein the static pressure grooves each has a depth which is in a range from 100 μm to 1 mm.

2. The seal ring according to claim 1 , wherein

each of the static pressure grooves is formed linearly in a radiation direction.

3. The seal ring according to claim 1 , wherein

the communication grooves together form a continuous annular path.

4. The seal ring according to claim 1 , wherein

each of the static pressure grooves is formed deeper on an inner diameter side than on the outer diameter side.

5. The seal ring according to claim 2 , wherein

each of the static pressure grooves is formed deeper on an inner diameter side than on the outer diameter side.