Patent ID: 9366459
Filing Date: 2016-06-14
CPC Classification: F25B

Claim Text:
1. A cryogenic refrigerator comprising: a compressor having a return end and a suction end that selectively connects to an expansion space; a housing having an assist space that communicates to the return end; a cylinder having one end connected to the housing and another end connected to the expansion space; a displacer that undergoes a reciprocating motion inside the cylinder, and tolerates flow of a working gas to and from the expansion space via a gas channel provided inside the displacer; and a drive shaft that extends in an axial direction and is accommodated within the housing and drives the displacer, wherein the drive shaft includes a first shaft part that extends in the axial direction and is sealed and supported by a first seal member that is formed by a slipper seal, and a second shaft part that extends in the axial direction and is sealed and supported by a second seal member, the first shaft part having an end opposing the housing to form the assist space, the second shaft part having an end connecting to the displacer, and wherein a first cross sectional area of the first shaft part passing through the first seal member and a second cross sectional area of the second shaft part passing through the second seal member are mutually different.