Abstract: A gas compressor for use in a gas refrigerator includes a compression space having a volume varied with a positional shift of a piston when the latter reciprocates in a cylinder, a first buffer space communicating with the compression space in one direction with respect to the compression space and a second buffer space communicating with the compression space in the opposite direction. Forces acting on working surfaces of the piston are set in such a way that, when a reciprocation stroke of the piston is to be lengthened, a shift of a neutral position of the piston reciprocation toward the compression space is prevented and, when the reciprocation stroke is to be shortened, a shift of the neutral position away from the compression space is prevented, so that the dead space in the compression space is minimized and a highly efficient operation can be realized in a wide output control range.

Abstract: A Stirling refrigerator has a cold-finger in which a displacer can reciprocate in accordance with changes in pressure inside the cold-finger which are produced by a compressor. A spring is connected between the displacer and the cold-finger in order to brake gradually the movement of the displacer at the ends of its stroke. The spring has a greater spring constant when it is deformed by the displacer being near either end of its stroke than when the spring is in, or near, a neutral position.

Abstract: A refrigerator comprising a cold finger having an expansion space and a first compression space defined by a displacer, a regenerator connected to the expansion space and the first compression space, a cylinder having a second compression space and a buffer space defined by a piston, and a communicating tube connecting the first compression space to the second compression space. The working space thus defined is filled with the working gas so that a thermodynamic cycle can be generated in the working gas within the working space to generate coldness within the expansio space by reciprocatingly moving the piston and the displacer with a predetermined phase relationship therebetween. The refrigerator further comprises a first passage having a check valve between the working space and the buffer space, and a second connecting passage connecting the drain space and the buffer space.

Abstract: A gas cycle machine includes a moving coil composed of a first moving coil portion and a second moving coil portion opposing to the first moving coil portion and a magnetic circuit is constituted such that magnetic flux in a first gap in which the first moving coil portion is disposed passes through the first moving coil portion inwardly and magnetic flux in a second gap in which the second moving coil portion is disposed passes through the latter outwardly. Magnetic flux of a permanent magnet passes through the first and the second gaps in opposite directions, respectively, and, therefore, a closed magnetic circuit is composed of the permanent magnet, a cylinder of soft iron and an annular disc, which eliminates the necessity of providing a large circular disc as in the conventional engine.

Abstract: A cold finger portion of a refrigerator is coupled to a movable member by means of a spring member having a linear characteristics to form a vibration system make phase difference between pressure variation and movement of the movable member and amplitude thereof possible to set at optimum values and to make a center of movement of the movable member constant by the linearity of the spring member regardless of operating condition.

Abstract: A refrigerator has a reciprocation portion including a piston and a portion of a linear motor and having an angular resonance frequency W defined by the following equation: ##EQU1## where m=total mass of the reciprocation portionSp=area of a working surface of the pistonPa=amplitude of pressure variation of a working gas in a compression space of the refrigerator.alpha.=phase difference between a displacement of the piston and pressure variation of the working gas in the compression spaceS=stroke of the pistonKs=spring constant of a support spring of the pistonand an a.c. power source for driving the reciprocation portion, the power source has an angular frequency W.sub.o substantially equal to said angular frequency W with an acceptable error therebetween being .+-.10%.

Abstract: In a vibration-reducing apparatus for a direct-acting type stirling engine, a change of pressure caused by the reciprocal movement of a displacer is applied to a power piston to produce a mechanical force, and the mechanical force is converted into an electric power by a direct-acting type electric generator which is directly connected to the power piston so as to effect reciprocating movements with the power piston.