Single-headed-piston type refrigerant compressor with means for preventing rotation of the piston about its own axis within the cylinder bore

Abstract

A single headed piston type refrigerant compressor having a cylinder block forming therein a plurality of cylinder bores receiving a plurality of single-headed pistons for reciprocation therein, and a front housing joined to the cylinder block to define a crank chamber for receiving therein a cam plate. An extended bore-forming portion of the cylinder block having partial cylindrical guide surfaces each being continuous with the corresponding cylinder bore and capable of being in slide contact with the piston head portion of the single-headed piston and the outer circumference of a shoe-holding portion of the single-headed piston is formed by extending a peripheral portion of a front end of the cylinder block into the crank chamber. A projecting portion formed on each single head piston protrudes from a side end surface of the shoe-holding portion extending behind the piston head portion into the crank chamber. Therefore, the extended bore-forming portion can additionally be extended toward the crank chamber by a length corresponding to the distance of dislocation of the projecting portion into a space on the front side of the crank chamber to increase additionally the length of contact of the piston with cylinder bore.