Cryogenic refrigerator

A cryogenic refrigerator comprising:

• a scotch yoke mechanism including an eccentric rotating body and a yoke plate that reciprocates by rotation of the eccentric rotating body, the yoke plate comprising a first yoke plate side surface and a second yoke plate side surface opposite the first yoke plate side surface, each of the first and second yoke plate side surfaces comprising a groove, the groove extending in a direction of the yoke plate's reciprocation;
• a displacer connected to the yoke plate so as to reciprocate together with the yoke plate;
• a cylinder that houses the displacer and form an expansion space for refrigerant gas in a space with the displacer;
• and
• an airtight container provided on a high-temperature side of the cylinder, and that houses the scotch yoke mechanism and receive the refrigerant gas discharged from the expansion space,
• wherein the airtight container includes a supporting unit that supports the first and second yoke plate side surfaces so as to restrict tilting of the yoke plate around a rotary shaft of the eccentric rotating body,
• wherein the supporting unit comprises a guide rail extending in the direction of the yoke plate's reciprocation and inserted into the groove, and a plurality of balls arranged within the groove and rollably held between the groove and the guide rail such that the yoke plate reciprocates along the guide rail,
• wherein the airtight container comprises an inner wall surface arranged in slidable contact with the first and second yoke plate side surfaces.