Electric compressor

Abstract

A compressor includes a motor unit formed of a stator and a rotor, a compressor mechanism driven by the motor unit, and an enclosed container accommodating the foregoing elements. The compressor mechanism includes a cylinder block equipped with a compressing chamber and a piston. A shaft directly coupled to the rotor that drives the piston is supported by a double-sided bearing system, namely, a main bearing and a sub bearing. This structure allows preventing the shaft from slanting, and reducing a loss and a noise caused by sliding. As a result, a low profile, highly reliable and efficient compressor is obtainable.

What is claimed is:  
     
         1 . An electric compressor comprising: 
 (a) a motor unit including a stator with a winding, and a rotor with a rotor iron-core and a permanent magnet;    (b) a compressor mechanism driven by the motor unit and including: 
 (b-1) a shaft including an eccentric shaft section, a main shaft section and a sub shaft section, the main shaft section and the sub shaft section sandwiching the eccentric shaft section vertically and being placed coaxially,;  
 (b-2) a cylinder block including a compressing chamber;  
 (b-3) a main bearing, disposed in the cylinder block such that the main bearing crosses with an axial core of the compressing chamber at right angles, for rotatably supporting the main shaft section;  
 (b-4) a sub bearing, disposed in the cylinder block, for rotatably supporting the sub shaft section;  
 (b-5) a piston for reciprocating in the compressing chamber;  
 (b-6) a linking means for coupling the piston with the eccentric shaft section; and  
   (c) an enclosed container for pooling lubricant oil and accommodating the motor unit and the compressor mechanism.    
     
     
         2 . The compressor of  claim 1 , wherein the main bearing does not cross with a plane which includes an end section of rotor iron-core on the compressor mechanism side and is orthogonal to an axial core of the main shaft section.  
     
     
         3 . The compressor of  claim 2 , wherein the main bearing is made of iron-based material.  
     
     
         4 . The compressor of  claim 1 , wherein the rotor iron-core has a hollow bore at its end section on the compressor mechanism side, and the main bearing extends into the bore.  
     
     
         5 . The compressor of  claim 4 , wherein the main bearing is made of non-magnetic material.  
     
     
         6 . The compressor of  claim 1 , wherein the permanent magnet is made of rare-earth material.  
     
     
         7 . The compressor of  claim 1 , wherein the motor unit is driven at a plurality of frequencies including a frequency not lower than a commercial power frequency.  
     
     
         8 . The compressor of  claim 1 , wherein the stator includes a plurality of teeth, and the winding is wound on the teeth via insulating material.  
     
     
         9 . The compressor of  claim 1 , wherein the motor unit starts working as an induction motor, and when its rotation becomes near a synchronizing rotation, synchronous pull-in is carried out for synchronous operation.