US Patent 9964102 Variable displacement compressor with drain passage

A variable displacement compressor includes a swash plate, a housing and a displacement control valve. The housing has a crank chamber where the swash plate is disposed, a discharge chamber and a suction chamber. The housing has plural bolt holes and is formed by separate members fastened together by plural bolts inserted through the bolt holes. The displacement control valve has a first valve member movable to connect the crank chamber and the discharge chamber, controlling the position of the first valve member to vary compressor displacement. The displacement control valve has a valve chamber and a second valve member serving to connect the crank chamber and the suction chamber in the valve chamber. The valve chamber is connected to the crank chamber by a drain passage part of which serves as the bolt hole located at the lowest of the plural bolt holes when the compressor is installed.