Refrigeration compressor and a method for assembling such a refrigeration compressor

Abstract

This refrigeration compressor includes an electric motor having a stator and a rotor provided with an axial through passage, a compression unit adapted for compressing refrigerant, and a drive shaft adapted for driving the compression unit, the drive shaft extending into the axial through passage of the rotor. The rotor is slide-fitted on the drive shaft.

1 . A refrigeration compressor comprising:
 an electric motor having a stator and a rotor, the rotor being provided with an axial through passage,   a compression unit adapted for compressing refrigerant,   a drive shaft shaft adapted for driving the compression unit, the drive shaft extending into the axial through passage of the rotor and being connected to the rotor, the drive shaft extending, in use, substantially vertically, and   a positioning element secured on the drive shaft, the positioning element having an axial stop surface on which rests a lower end portion of the rotor, the axial stop surface being arranged to slidably co-operate with a lower end portion of the rotor,   wherein the connection between the rotor and the drive shaft is arranged to allow limited relative movements between the rotor and the drive shaft during start and normal operations of the refrigeration compressor.   
     
     
         2 . The refrigeration compressor according to  claim 1 , wherein the rotor is slide-fitted on the drive shaft. 
     
     
         3 . The refrigeration compressor according to  claim 1 , further comprising a locking element adapted to rotatably couple the drive shaft to the rotor. 
     
     
         4 . The refrigeration compressor according to  claim 3 , wherein an outer surface of the drive shaft has a first longitudinal recess, and an inner surface of the rotor has a second longitudinal recess, the first and second longitudinal recesses being circumferentially aligned and the locking element extending into the first and second longitudinal recesses. 
     
     
         5 . The refrigeration compressor according to  claim 3 , wherein the locking element is adapted to allow limited relative angular sliding movements between the rotor and the drive shaft. 
     
     
         6 . The refrigeration compressor according to  claim 1 , wherein the positioning element is a positioning ring secured to the drive shaft. 
     
     
         7 . The refrigeration compressor according to  claim 1 , wherein the positioning element is heat shrink fitted to the drive shaft. 
     
     
         8 . The refrigeration compressor according to  claim 1 , further comprising a first axial abutment surface provided on the rotor and a second axial abutment surface provided on the drive shaft, a predetermined axial gap being provided between the first and second axial abutment surfaces in order to allow limited relative axial movements between the drive shaft and the rotor. 
     
     
         9 . The refrigeration compressor according to  claim 8 , wherein the first and second axial abutment surfaces are arranged to prevent the rotor from axially moving beyond a predetermined position towards the compression unit. 
     
     
         10 . A method for assembling a refrigeration compressor according to  claim 1 , comprising the steps of:
 connecting the rotor to the drive shaft so as to allow limited relative movements between the rotor and the drive shaft during start and normal operations of the refrigeration compressor, and   securing the positioning element to the drive shaft so that the lower end portion of the rotor rests on the axial stop surface of the positioning element.   
     
     
         11 . The method according to  claim 10 , wherein the connecting step consists in slide-fitting the rotor to the drive shaft.