Abstract: Provided is a cryocooler configured to be mountable on a vacuum container to cool a liquid refrigerant container. The cryocooler includes an attachment flange forming a refrigerant gas chamber between a mounting port of the vacuum container and the attachment flange when the cryocooler is mounted on the mounting port, and movable in a detachment direction by raising a pressure of the refrigerant gas chamber, and a cooling stage cooling an object to be cooled disposed inside the vacuum container and movable from a cooling position in contact with the object to be cooled to a non-cooling position separated from the object to be cooled in response to a movement of the attachment flange in the detachment direction. The refrigerant gas chamber is connected to the liquid refrigerant container.

Abstract: There is provided a cryocooler including a cryocooler cylinder, a pressure switching valve that generates a periodic pressure fluctuation inside the cryocooler cylinder, and a sensor that measures a periodic deformation of the cryocooler cylinder, which is caused by the periodic pressure fluctuation inside the cryocooler cylinder.

Abstract: Provided is a cryocooler configured to be mountable on a vacuum container to cool a liquid refrigerant container. The cryocooler includes an attachment flange forming a refrigerant gas chamber between a mounting port of the vacuum container and the attachment flange when the cryocooler is mounted on the mounting port, and movable in a detachment direction by raising a pressure of the refrigerant gas chamber, and a cooling stage cooling an object to be cooled disposed inside the vacuum container and movable from a cooling position in contact with the object to be cooled to a non-cooling position separated from the object to be cooled in response to a movement of the attachment flange in the detachment direction. The refrigerant gas chamber is connected to the liquid refrigerant container.

Abstract: There is provided a cryocooler including a cryocooler cylinder, a pressure switching valve that generates a periodic pressure fluctuation inside the cryocooler cylinder, and a sensor that measures a periodic deformation of the cryocooler cylinder, which is caused by the periodic pressure fluctuation inside the cryocooler cylinder.

Abstract: A rotary valve mechanism of a cryocooler includes a valve rotor and a valve stator. A rotor recessed portion is formed such that the rotor recessed portion fluidally communicates with a stator recessed portion at a first opening degree at a second phase of a valve rotation. The valve rotor includes a first rotor communication groove and/or a second rotor communication groove formed in the valve rotor such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at a first phase preceding the second phase, and/or the valve stator includes a stator communication path formed in the valve stator such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at the first phase preceding the second phase.

Abstract: A rotary valve mechanism of a cryocooler includes a valve rotor and a valve stator. A rotor recessed portion is formed such that the rotor recessed portion fluidally communicates with a stator recessed portion at a first opening degree at a second phase of a valve rotation. The valve rotor includes a first rotor communication groove and/or a second rotor communication groove formed in the valve rotor such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at a first phase preceding the second phase, and/or the valve stator includes a stator communication path formed in the valve stator such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at the first phase preceding the second phase.

Abstract: A rotary valve mechanism of a cryocooler includes a valve rotor and a valve stator. A rotor recessed portion is formed such that the rotor recessed portion fluidally communicates with a stator recessed portion at a first opening degree at a second phase of a valve rotation. The valve rotor includes a first rotor communication groove and/or a second rotor communication groove formed in the valve rotor such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at a first phase preceding the second phase, and/or the valve stator includes a stator communication path formed in the valve stator such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at the first phase preceding the second phase.

Abstract: A rotary valve mechanism of a cryocooler includes a valve rotor and a valve stator. A rotor recessed portion is formed such that the rotor recessed portion fluidally communicates with a stator recessed portion at a first opening degree at a second phase of a valve rotation. The valve rotor includes a first rotor communication groove and/or a second rotor communication groove formed in the valve rotor such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at a first phase preceding the second phase, and/or the valve stator includes a stator communication path formed in the valve stator such that the rotor recessed portion fluidally communicates with the stator recessed portion at an opening degree which is smaller than the first opening degree at the first phase preceding the second phase.

Abstract: A cryogenic refrigerator according to an embodiment of the present invention is used in cooling a superconducting magnet. The cryogenic refrigerator includes a crankpin bearing of a scotch yoke. The crankpin bearing is made of a cylindrical nonmagnetic resin material. The crankpin bearing includes a cylindrical inner wall and a cylindrical outer wall. The cylindrical inner wall supports a crankpin. The crankpin is eccentrically attached to an output shaft of a motor slidably in a circumferential direction. The cylindrical outer wall contacts with an inner wall of a window portion of the scotch yoke. The cylindrical inner wall is made of another nonmagnetic resin material different from the nonmagnetic resin material of the cylindrical outer wall. Hardness of the cylindrical inner wall is higher than hardness of the cylindrical outer wall.

Abstract: A cryogenic refrigerator includes a pressure switching valve with a rotational element for switching between channels. The cryogenic refrigerator includes a first member located on one side in a direction of a rotational axis of the rotational element; a second member located on another side in the direction of the rotational axis of the rotational element; a bearing rotatably supporting the rotational element; and an elastic element. The first and second members sandwich the bearing via the elastic element.

Abstract: A sealing boot of elastomeric material for hermetically enclosing an annular opening between a support member and a movable member axially reciprocable on the support member, the sealing boot including a tubular bellows which is integrally formed at one end thereof with a first cylindrical sealing sleeve portion coupled over the support member and at the other end thereof with a second cylindrical sealing sleeve portion coupled within the movable member, the sealing boot being characterized in that the first cylindrical sealing sleeve portion being connected substantially at its center to the one end of the tubular bellows and being formed at its inner end shoulder with an annular thick wall tapering radially toward the inner wall surface of the tubular bellows.