ROTARY COMPRESSOR

PURPOSE:To prevent a bearing from damage and to reduce vibration, by forming a recessed part in a roller, opposed to a recessed part formed in the roller side of a subbearing, and mounting a balancer to a main shaft, passing through space formed by the two recessed parts, so as to prevent generation of bending moment. CONSTITUTION:A subbearing 10 forms a recessed part in the side of a roller 5, while space is formed by the roller 5, crank part 4 and the subbearing 10, and a balancer 11 is mounted to the subbearing 10 of a main shaft 3 in a side opposite to the eccentric side of the crank part 4 in said space. Hereupon, centrifugal forces, generated by the crank part 4 of the main shaft 3, roller 5 and the balancer 11, are balanced around the rotary axis of the main shaft 3. Consequently, small bending moment is generated in the main shaft 3 while it is in rotation, and the main shaft 3 stably rotates. While the total sum of the centrifugal forces, acting on the main shaft 3, decreases because the crank part 4 of the main shaft 3 and the roller 5 are formed in light weight, and a compressor can form the main shaft in a thin size while prevent generation of seizure and scuffing of a main bearing 8 and reduce an input, vibration and noise.