Patent ID: 8807973

Claim:
A 2-stage rotary compressor, comprising: a hermetic container; a rotating shaft provided in the hermetic container, that transfers a rotational force; a low pressure compression assembly including a low pressure roller eccentrically rotated around a center of the rotating shaft, a low pressure cylinder that accommodates the low pressure roller, and a low pressure vane that partitions an inner space of the low pressure cylinder; a high pressure compression assembly including a high pressure roller eccentrically rotated around the center of the rotating shaft, a high pressure cylinder that accommodates the high pressure roller, and a high pressure vane that partitions an inner space of the high pressure cylinder; a connection pipe that provides a passage for the refrigerant compressed in the low pressure compression assembly to be introduced into the high pressure compression assembly; and an injection pipe connected to the connection pipe, wherein a ratio of a stroke volume V 2 of the high pressure cylinder to a stroke volume V 1 of the low pressure cylinder satisfies the relational expression of 0.43<V 2 /V 1 <0.82, and wherein an inner diameter of a middle portion of the connection pipe is greater than inner diameters of both end portions of the connection pipe.