Cryocooler and rotary valve mechanism

A cryocooler, comprising:

• a compressor for a working gas, the compressor including a compressor discharging port and a compressor suction port;
• an expander including a gas expansion chamber, the gas expansion chamber defining an axial orientation of the expander, and a low-pressure gas chamber communicating with the compressor suction port;
• and
• a rotary valve component, the rotary valve component defining a valve-rotational direction about a valve-rotational axis and the valve-rotational axis being orthogonal to the axial orientation of the expander, the rotary valve component being composed of
• a valve stator provided with
• a stator planar surface perpendicular to the valve-rotational axis,
• a high-pressure gas inflow port opening onto the stator planar surface and communicating with the compressor discharging port, and
• in the stator planar surface, a stator recessed portion communicating with the gas expansion chamber, and defining a stator-recessed-portion front edge line and a stator-recessed-portion rear edge line located apart from each other in the valve-rotational direction,
• the valve stator being arranged in the low-pressure gas chamber, and
• a valve rotor provided with
• a rotor planar surface perpendicular to the valve-rotational axis and in surface-contact with the stator planar surface, and
• in the rotor planar surface, a rotor recessed portion communicating with the high-pressure gas inflow port, and defining a rotor-recessed-portion front edge line and a rotor-recessed-portion rear edge line located apart from each other in the valve-rotational direction,
• the valve rotor being disposed in the low-pressure gas chamber such as to rotate with respect to the valve stator, about the valve rotational axis;
• wherein
• the rotor recessed portion is formed in the valve rotor such that the rotor-recessed-portion front edge line passes through the stator-recessed-portion front edge line and the rotor recessed portion fluidally communicates with the stator recessed portion at a first phase of rotary-valve-component rotation, and such that the rotor-recessed-portion rear edge line passes through the stator-recessed-portion rear edge line and the rotor recessed portion is fluidally separated from the stator recessed portion at a second phase of the rotary-valve-component rotation, and
• the rotor recessed portion is shaped such that at the first phase of the rotary-valve-component rotation the rotor-recessed-portion front edge line overlappingly coincides with the stator-recessed-portion front edge line.