Patent ID: 6907730

Claim:
A displacer and seal assembly for Stirling cycle machines comprising: a displacer ( 2 ), a power piston ( 9 ), a cylinder ( 5 ), a seal ( 1 ) and a retaining ring ( 3 ); said displacer ( 2 ) and said power piston ( 9 ) structured so as to reciprocate with each other in a phase relationship along the inner peripheral surfaces ( 5 a , 5 b ) of a cylinder bore formed concentrically with said cylinder ( 5 ); said displacer ( 2 ) comprising a cylindrical body portion ( 2 a ), and a step ( 2 b ) and a rod ( 4 ), both of which are provided concentrically with said body portion ( 2 a ); the outer periphery of said body portion ( 2 a ) having a diameter to be inserted into the inner peripheral surface ( 5 a ) of said cylinder ( 5 ) with a predetermined radial clearance; said step ( 2 b ) integrally disposed on one end of said body portion ( 2 a ) and having a diameter smaller than the outer periphery of said body portion; a side surface ( 2 d ), which connects the outer periphery of said step ( 2 b ) to the outer peripheral end of said body portion ( 2 a ), formed perpendicularly to the axial direction; said rod ( 4 ) integrally disposed on one end of said step ( 2 b ) and having a circular cross sectional shape; said seal ( 1 ) formed in a ring shape and having a circular hole in the center thereof; the outer periphery of said seal ( 1 ) having a diameter to be closely inserted into the inner peripheral surface ( 5 a ) of said cylinder ( 5 ); the inner periphery of the circular hole in said seal ( 1 ) having a diameter to be attached to the outer periphery of said step ( 2 b ) with a predetermined radial clearance; said retaining ring ( 3 ) formed in a cylindrical shape and having a through hole in the center thereof; the outer periphery of said retaining ring ( 3 ) formed so as to have the same diameter as the outer periphery of said body portion ( 2 a ); one end surface ( 3 a ) of said retaining ring ( 3 ) formed perpendicularly to the axial direction; said rod ( 4 ) passing through a center hole ( 9 a ) that is formed in the center of said power piston ( 9 ) and radially supported by a bearing seal ( 10 ) that is provided in said center hole ( 9 a ); said seal ( 1 ) inserted on the outer periphery of said step ( 2 b ); said retaining ring ( 3 ) installed in a position at which no axial pressure is applied to said seal ( 1 ) that is inserted on the step ( 2 b ); wherein said seal ( 1 ) is structured to freely move in the radial direction thereof between said one end surface ( 3 a ) of said retaining ring ( 3 ) and said side surface ( 2 d ) of said step ( 2 b ).