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: A seal means for use in the Stirling engine or the like, the seal means comprising: a cylinder including a piston reciprocating therein, and a buffer chamber located in one of the spaces produced at the both sides of the piston; a tank for storing the working fluid in the buffer chamber when the engine is at rest, the tank being located outside the cylinder; a means for introducing the working fluid in the tank into the buffer chamber under pressure when the engine is started; a crank shaft driven by means of the piston through a piston rod; a crankcase for accommodating the crank shaft; a plurality of packings for preventing the working fluid in the buffer chamber from entering the crankcase by flowing along the outer surface of the moving piston rod, the packings being arranged in contact with the outer surface of the piston rod; and a means for returning the working fluid leaked in the packings from the buffer chamber through the moving piston rod to the buffer chamber.

Abstract: A Stirling engine wherein a pressure variation is provided by a reciprocative movement of a displacer and is effected upon a power piston to obtain an output motive force. A first elastic film is provided at the displacer rod projecting into the crankcase so as to produce a first hermetically sealed space bounded by the expansion cylinder. A second elastic film is provided at the power piston rod so as to produce a second hermetically sealed space below the power piston. A pressure adjusting device equalizes the mean pressure of a reactive space, which includes the first and the second hermetically sealed spaces, and that of the crankcase.