Patent ID: 7618245

Claim:
A fluid machine comprising: a casing ( 31 ), the casing ( 31 ) containing therein (i) a compression mechanism ( 50 ) for compressing fluid and (ii) an expansion mechanism ( 60 ) for generating rotational power by the expansion of fluid, wherein: (a) a rotating shaft ( 70 ) of the compression mechanism ( 50 ) and a rotating shaft ( 80 ) of the expansion mechanism ( 60 ) are coupled together; (b) oil supply grooves ( 74 , 84 ) in fluid communication with each other are formed respectively in the rotating shafts ( 70 , 80 ); and (c) a seal mechanism (S, R) for providing sealing between coupling portions of the rotating shafts ( 70 , 80 ) is provided; (d) the rotating shaft ( 80 ) has a shaft end with a convex portion ( 85 ) and the rotating shaft ( 70 ) has a shaft end with a concave portion ( 75 ) into which the convex portion ( 85 ) is engaged; and (e) the seal mechanism (S, R) comprises (i) a seal groove (S) formed in a peripheral surface over the circumferential direction of either one of the convex portion ( 85 ) and the concave portion ( 75 ) and (ii) a seal member (R) engaged into the seal groove (S), wherein the fluid machine is provided with locating means ( 8 ) by which the rotating shafts ( 70 , 80 ) are coupled together in a predetermined phase relation which permits correspondence between the compression stroke of the compression mechanism ( 50 ) and the expansion stroke of the expansion mechanism ( 60 ).