Closed cycle gas refrigerator

Claim 1

A regrigerator having a working space including a compression space held at a relatively high temperature during operation and having a volume varied according to a displacement of a piston arranged adjacent said compression space or displacements of said piston and a displacer, an expansion space held at a relatively low temperature during operation and having a volume varied according to said displacement of said displacer arranged adjacent said expansion space, a cooler, a regenerator and a freezer disposed between said compression space and said expansion space to communicate therebetween and a working gas filling said working space and performing a thermodynamic cycle by movements of said piston and said displacer in different phase to generate a cold production therein, comprising a linear motor including an armature coil and a closed magnetic circuit for driving said piston, a support spring for supporting said piston in a constant position in a stationary condition and a power source for driving said armature coil, wherein an angular resonance frequency ω of a reciprocation portion including said piston and a portion of said linear motor is defined by the following equation: ##EQU5## where m=total mass of said reciprocation portion SP=area of a working surface of said piston Pa=amplitude of pressure variation of said working gas in said compression space α=phase difference between a displacement of said piston and pressure variation of said working gas in said compression space S=stroke of said piston Ks=spring constant of said support spring and wherein an angular frequency of said power source ω o is substantially equal to said angular resonance frequency ω with an acceptable error therebetween being ±10%.