Seal ring

A seal ring which is mounted on an annular groove formed on one member consisting of either a housing having a shaft hole or a rotary shaft inserted into said shaft hole, partly projects from said annular groove and contacts a surface of other member consisting of either said housing or said rotary shaft, and slidably contacts a side wall surface of said annular groove at a non-sealed fluid side thereof, thereby sealing an annular gap between said one member and said other member,

• wherein an outer diameter side of said side surface of said ring to be subjected to at least said side wall surface of said annular groove is formed as an inclined surface having an inclined angle in such a way as to decrease a width of said ring from said outer diameter side of said side surface of said ring to an inner diameter side of said side surface thereof;
• said inclined angle of said inclined surface with respect to a plane perpendicular to an axial direction of said seal ring is set to a range of 1.5 to 5 degrees;
• said inner diameter side of said side surface of said ring is formed as a non-inclined surface;
• a concave portion which does not contact said side wall surface of said annular groove and communicates with an inner circumferential surface of said ring is formed on a portion of said inner diameter side of said side surface of said ring not projecting from said annular groove;
• and
• said concave portion is V-shaped along a circumferential direction of said seal ring.