GM cryocooler with buffer volume communicating with drive chamber

A GM cryocooler comprising:

• a compressor having a compressor discharge port and a compressor suction port;
• a displacer capable of reciprocating in an axial direction;
• a displacer cylinder which accommodates the displacer;
• a drive piston connected to the displacer so as to drive the displacer in the axial direction;
• a drive chamber in which the drive piston is driven;
• a main pressure switching valve configured to alternately connect the displacer cylinder to the compressor discharge port and the compressor suction port;
• an auxiliary pressure switching valve configured to alternately connect the drive chamber to the compressor discharge port and the compressor suction port;
• a buffer volume connected between the auxiliary pressure switching valve and the compressor;
• and
• a second auxiliary intake on-off valve connected between the compressor discharge port and the buffer volume,
• wherein the auxiliary pressure switching valve includes an auxiliary intake on-off valve that connects the compressor discharge port to the drive chamber, and an auxiliary exhaust on-off valve that connects the compressor suction port to the drive chamber,
• wherein the buffer volume is connected between the compressor discharge port and the auxiliary intake on-off valve, and
• wherein the second auxiliary on-off valve is opened after an intake start timing of the drive chamber through the auxiliary intake on-off valve.