Variable speed scroll compressor

Abstract

This variable speed scroll compressor includes a closed casing including a low pressure volume and a high pressure volume, and an electric motor arranged in the low pressure volume and including a rotor and a stator, the rotor including permanent magnets, the stator including a stator core provided with a plurality of radially extending tooth portions and with a plurality of slots formed between the radially extending tooth portions, and stator windings each wound on the radially extending tooth portions. Each stator winding is wound around a respective tooth portion and includes winding portions extending respectively in the slots formed on each side of the respective tooth portion.

1 . A variable speed scroll compressor comprising:
 a closed casing comprising a low pressure volume and a high pressure volume,   a compression unit adapted for compressing refrigerant,   an electric motor arranged in the low pressure volume and comprising a rotor and a stator. the rotor including permanent magnets, the stator including a stator core provided with a plurality of radially extending tooth portions and with a plurality of slots formed between the radially extending tooth portions, and stator windings wound on the radially extending tooth portions, each stator winding being wound around a respective tooth portion,   a drive shaft adapted for driving the compression unit, the drive shaft being rotatably coupled to the rotor, and   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 sliding movements between the rotor and the drive shaft,   
       wherein at least one slot formed between a first and a second adjacent radially extending tooth portions includes a first slot portion in which extends a winding portion of a first stator winding wound around the first radially extending tooth portion, a second slot portion in which extends a winding portion of a second stator winding wound around the second radially extending tooth portion, and a third slot portion arranged between the first and second slot portions and defining a refrigerant flow passage. 
     
     
         2 . The variable speed scroll compressor according to  claim 1 , wherein the ratio of the sum of the refrigerant flow passages cross-sectional areas to the stator cross-sectional area is between 3 and 14%. 
     
     
         3 . The variable speed scroll compressor according to  claim 1 , wherein the variable speed scroll compressor is configured to force at least a part of the refrigerant entering the refrigerant suction inlet to pass through the refrigerant flow passages of the slots. 
     
     
         4 . The variable speed scroll compressor according to  claim 1 , further comprising an intermediate jacket surrounding the stator, the intermediate jacket delimiting an annular outer volume with the closed casing and at least an inner chamber, which contains a first winding head of the stator directed towards the high pressure volume. 
     
     
         5 . The variable speed scroll compressor according to  claim 1 , further comprising a locking element adapted to rotatably couple the drive shaft to the rotor. 
     
     
         6 . The variable speed scroll compressor according to  claim 5 , 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. 
     
     
         7 . The variable speed scroll compressor according to  claim 5 , wherein the locking element is adapted to allow limited relative angular sliding movements between the rotor and the drive shaft 
     
     
         8 . The variable speed scroll compressor according to  claim 1 , further comprising a positioning element secured on the drive shaft the positioning element having an axial stop surface arranged to slidably co-operate with an end portion of the rotor opposite to the compression unit. 
     
     
         9 . The variable speed scroll compressor according to  claim 8 , wherein the positioning element is a positioning ring secured to the drive shaft.