Patent ID: 7836696

Claim:
A fluid machine comprising: means for compressing or expanding a working fluid which is heated to be brought into a vapor phase state after circulating in a cycle; means for storing lubricant oil for lubricating a sliding surface of the fluidization means; a lubricant oil feed passage for guiding the lubricant oil stored in the storing means to a sliding portion of the compressing or expanding means by a flow of the working fluid; means for adjusting a sliding surface pressure of the sliding portion, and means for controlling the adjusting means to perform a sliding surface pressure decreasing mode which involves decreasing the sliding surface pressure of the sliding portion, wherein the working fluid flows inside the fluid machine with the sliding surface pressure of the sliding portion decreased as compared with that in a normal operation of the compressing or expanding means by the adjusting means, and thereafter the decreasing of the sliding surface pressure by the adjusting means is released; and wherein the controlling means starts the sliding surface pressure decreasing mode when a temperature of a coolant for an engine exceeds a predetermined temperature in actuation of the compressing or expanding means.