ROTARY COMPRESSOR

PURPOSE:To prevent generation of seizure between a main shaft and a main bearing, by forming in the periphery of the main shaft a hollow part of a rotor cutting it from its bottom end surface and positioning an upper end surface of the main bearing higher than the bottom end surface of the rotor so as to reduce a margin of deflection in the main shaft even when it rotates at a high speed. CONSTITUTION:A rotor 23, being cut from its bottom end surface, forms a hollow part in the periphery of a main shaft 10, and the upper end surface of a main bearing 16, being placed in said hollow part, is situated in the vicinity of the center of gravity of the rotor 23. While a compressor is in operation, an impeller pump 22, provided in the bottom of the main shaft 10, carries lubricating oil 4 to a cut groove (not shown in the drawing) in an internal wall of the main bearing 16 further to an upper end surface of the main shaft 10. During this time, the lubricating oil is carried into a part between the main shaft 10 and the main bearing 16, forming an oil film. While the main shaft 10, by the above constitution, enables its deflecting margin by the main bearing 16, and the compressor, even when it is in high speed operation, can prevent seizure by forming the oil film between the main shaft 10 and the main bearing 16.