US Patent 7891956 Rotary compressor

A rotary compressor includes a driving shaft having an eccentric portion, a cylinder, and a roller installed on an outer circumference of the eccentric portion to contact an inner circumference of the cylinder, performing a rolling motion along the inner circumference and forming a fluid chamber to suck and compress fluid along with the inner circumference. A vane is installed elastically in the cylinder to contact the roller continuously. Discharge ports communicate with the fluid chamber. Suction ports communicate with the fluid chamber and are spaced apart from each other by a predetermined angle. A valve assembly selectively opens any one of the suction ports according to a rotation direction of the driving shaft. Compression spaces having different volumes are formed in the fluid chamber according to the rotation direction of the driving shaft such that two different compression capacities are formed.