Patent ID: 7467797

Claim:
A seal system comprising: a shaft supported by a housing; an elastic seal ring including an annular fitted part and a lip part, said annular fitted part to be fitted into a hole of the housing, said lip part extending from said fitted part inwardly in a radial direction in the shape of a substantially conical ring that is to be brought into contact with an outer periphery of said shaft; and a support ring including an annular joint part joined to said annular fitted part, and an annular supporting part, said annular supporting part defining a hole through which said shaft is to pass, extending from a side of said annular joint part to a middle region of said lip part, and supporting said lip part, from inwardly of said lip part, in the radial direction, wherein said lip part is formed so as to extend linearly when high pressure is not applied to said lip part and be tapered in cross section from an area at which non-contact with said annular supporting part begins toward an end of said lip part, such that a value of T 0 /T 1 falls within 0.3 to 0.7, with T 1 being a thickness of said lip part at the area at which non-contact with said annular supporting part begins, and T 0 being a thickness of said end of said lip part, and such that a value (D 1 -D 0 )/D 1 falls within 0.03 to 0.15, with D 0 being an inner diameter of said end of said lip part, and D 1 being an outer diameter of said shaft.