SEAL STRUCTURE AND POWER STEERING DEVICE

PROBLEM TO BE SOLVED: To provide a seal structure capable of reducing sliding rotation resistance of a position where radial one side of a seal ring is contacted with a peripheral surface of a first member, and a power steering device capable of reducing steering force required when a steering means connected to a valve body as a second member is steered and obtaining sufficient steering feeling. SOLUTION: The seal structure is provided with a cylindrical valve body 5 and a valve spool fitted so as to perform relative angle displacement by steering of a steering wheel; a valve housing 7 in which the valve body 5 is rotatably internally fitted to a pressurized liquid chamber 71; and the seal ring 8 fitted to an annular groove 4 provided on the valve body 5, pressed to one side in a radial direction and in an axial direction by the pressurized liquid of the pressurized liquid chamber 71 and preventing leakage of the pressurized liquid. A projection peripheral surface 81 having shorter length than length in an axial direction is provided on one side in a radial direction of the seal ring 8, an annular recession 82 is provided on the other side in a radial direction, and an elastic ring 9 for pressing the seal ring 8 to one side in the radial direction and in the axial direction by the pressurized liquid is provided in the annular recession 82. COPYRIGHT: (C)2009,JPO&INPIT