Pulse tube cryocooler and rotary valve unit for pulse tube cryocooler

A pulse tube cryocooler comprising:

• a regenerator which includes a regenerator high-temperature end and a regenerator low-temperature end;
• a pulse tube which includes a pulse tube high-temperature end and a pulse tube low-temperature end in communication with the regenerator low-temperature end;
• a rotary valve which alternately connects the regenerator high-temperature end to a compressor discharge port and a compressor suction port to generate a working gas pressure oscillation in the pulse tube, and which is connected to the pulse tube high-temperature end to control a phase delay of a working gas displacement oscillation in the pulse tube with respect to the working gas pressure oscillation, the rotary valve being operated according to a cooling valve timing for cooling the pulse tube cryocooler or a heating valve timing for heating the pulse tube cryocooler;
• and
• a reversible motor which is connected to the rotary valve to rotate the rotary valve around a rotary valve rotation axis,
• wherein the rotary valve includes:
• a valve stator,
• a first valve rotor which is connected to the reversible motor to rotate with respect to the valve stator around the rotary valve rotation axis, the first valve rotor being configured to alternately connect the regenerator high-temperature end to the compressor discharge port and the compressor suction port by a rotation,
• a second valve rotor which is connected to the reversible motor to rotate with respect to the valve stator around the rotary valve rotation axis, the second valve rotor being configured to alternately connect the pulse tube high-temperature end to the compressor discharge port and the compressor suction port by a rotation, and
• a valve rotor connection mechanism which connects the first valve rotor and the second valve rotor to each other such that when the reversible motor rotates in a forward direction, both valve rotors rotate around the rotary valve rotation axis while the first valve rotor holds a first relative angle relative to the second valve rotor, and when the reversible motor rotates in a backward direction, both valve rotors rotate around the rotary valve rotation axis while the first valve rotor holds a second relative angle relative to the second valve rotor, and
• wherein the second relative angle is different from the first relative angle.