Abstract: A seal ring includes a center axis, an outer peripheral surface, an inner peripheral surface, a side surface, and a groove. The center axis is a rotation center. The outer peripheral surface is an outward cylindrical surface whose center is positioned at the central axis. The inner peripheral surface is an inward cylindrical surface disposed between the center axis and the outer peripheral surface whose center is positioned at the central axis. The side surface connects the outer peripheral surface and the inner peripheral surface. The groove is formed in a dented groove from the side surface, extends along a radial direction spaced from the outer peripheral surface, has a first end connected to the inner peripheral surface and a second end at an opposite side of the first end, and returns oil entered from the first end to an inner peripheral surface side via the second end.

Abstract: Object: To provide a seal ring capable of both reducing a friction loss and reducing oil leakage. Solving Means: The seal ring includes an inner circumferential surface, an outer circumferential surface, side surfaces, a plurality of pockets, and recess regions. The outer circumferential surface is opposed to the inner circumferential surface. The side surfaces are orthogonal to the inner circumferential surface and the outer circumferential surface. The plurality of pockets are provided, spaced apart from one another in at least one of the side surfaces. The recess regions are provided in the at least one of the side surfaces and includes a plurality of independent recesses. In this seal ring, it is possible to both reduce the friction loss and reduce the oil leakage due to a function of buffering oil by the recess region.

Abstract: A seal ring includes a center axis, an outer peripheral surface, an inner peripheral surface, a side surface, and a groove. The center axis is a rotation center. The outer peripheral surface is an outward cylindrical surface whose center is positioned at the central axis. The inner peripheral surface is an inward cylindrical surface disposed between the center axis and the outer peripheral surface whose center is positioned at the central axis. The side surface connects the outer peripheral surface and the inner peripheral surface. The groove is formed in a dented groove from the side surface, extends along a radial direction spaced from the outer peripheral surface, has a first end connected to the inner peripheral surface and a second end at an opposite side of the first end, and returns oil entered from the first end to an inner peripheral surface side via the second end.