Swash plate type variable displacement compressor

Abstract

A swash plate type variable displacement compressor comprises cylinder bores, pistons, a suction chamber and a discharge chamber. A suction valve introduces a low pressure gas into a working chamber in each cylinder bore. A discharge valve introduces a high pressure gas in the working chamber into the discharge chamber during a compression stroke. A crank chamber communicates to each of the cylinder bores at rear sides of the pistons. A swash plate is tiltably supported on a drive shaft and connected to each of the pistons through associated rods. The swash plate makes the pistons reciprocate in response to its undulating swing motion and varies its inclination angle based upon pressure differential between pressure in the suction chamber and pressure in the crank chamber therefore adjusting discharge displacement. A gas supply passage communicates each cylinder bore to the crank chamber in order to supply gas having a lower pressure than that in the working chamber at the time of completing the compression stroke. A gas bleed passage communicates the crank chamber to the suction chamber in order to introduce gas in the crank chamber into the suction chamber. A pressure control valve is provided in the gas supply passage or the gas bleed passage to control pressure of gas in the crank chamber. A valve is provided for opening and closing the gas supply passage in the middle of the compression stroke of each of the pistons.