Hermetically sealed compressor

Abstract

A hermetically sealed compressor includes a sealed vessel filled with a coolant and a freezer oil, an electromotive element including a rotor and a stator and accommodated within the sealed vessel, and a compressing element accommodated within an upper region of the sealed vessel and adapted to be driven by the electromotive element. This compressing element is provided with a shaft, arranged so as to extend vertically and having the rotor mounted thereon, and a bearing for supporting the shaft. A first oil pump is provided in a lower portion of the shaft and opening into the freezer oil, a second oil pump is provided above the first oil pump and formed by a spiral groove, provided on an outer periphery of the shaft, and an inner peripheral wall surface of the rotor, and a third oil pump is provided above the second oil pump and formed by a spiral groove, provided on the outer periphery of the shaft, and an inner peripheral surface of the bearing.

1 . A hermetically sealed compressor comprising: 
 a sealed vessel filled with a coolant and a freezer oil;    an electromotive element including a rotor and a stator and accommodated within the sealed vessel;    a compressing element accommodated within an upper region of the sealed vessel and adapted to be driven by the electromotive element, the compressing element being provided with a shaft, arranged so as to extend vertically and having the rotor mounted thereon, and a bearing for supporting the shaft;    a first oil pump provided in a lower portion of the shaft and opening into the freezer oil;    a second oil pump provided above the first oil pump and formed by a spiral groove, provided on an outer periphery of the shaft, and an inner peripheral wall surface of the rotor; and    a third oil pump provided above the second oil pump and formed by a spiral groove, provided on the outer periphery of the shaft, and an inner peripheral surface of the bearing.    
     
     
         2 . The hermetically sealed compressor as claimed in  claim 1 , wherein the spiral groove of the second oil pump and the spiral groove of the third oil pump are formed continuously.  
     
     
         3 . The hermetically sealed compressor as claimed in  claim 2 , wherein the spiral groove of the second oil pump and the spiral groove of the third oil pump open in communication with a first gap formed between the rotor and the bearing.  
     
     
         4 . The hermetically sealed compressor as claimed in  claim 3 , wherein the first gap is 0.5 mm or smaller over the entire circumference thereof.  
     
     
         5 . The hermetically sealed compressor as claimed in  claim 2 , wherein the rotor has an upper end face formed with a bore for receiving the bearing and a second gap is formed between an inner peripheral surface of the bore and an outer peripheral surface of the bearing.  
     
     
         6 . The hermetically sealed compressor as claimed in  claim 5 , wherein the second gap is 1.0 mm or smaller over the entire circumference thereof.  
     
     
         7 . The hermetically sealed compressor as claimed in  claim 5 , wherein the bore has a depth of 5.0 mm or larger.  
     
     
         8 . The hermetically sealed compressor as claimed in  claim 3 , further comprising an axially elastically deformable washer interposed in the first gap.  
     
     
         9 . The hermetically sealed compressor as claimed in  claim 3 , wherein the rotor has a center of magnetism displaced below a center of magnetism of the stator and the first gap becomes almost zero over the entire circumference thereof when the rotor ascends by a magnetic force of attraction during operation.  
     
     
         10 . A hermetically sealed compressor comprising: 
 a sealed vessel filled with a lubricant oil;    an electromotive element including a rotor and a stator and accommodated within the sealed vessel;    a compressing element accommodated within the sealed vessel and adapted to be driven by the electromotive element, the compressing element being provided with a shaft, having an eccentric shaft portion and a main shaft portion, and a main bearing for supporting the shaft;    a first oil pump provided in a lower portion of the shaft and opening into the lubricant oil;    a second oil pump provided above the first oil pump and formed by a spiral groove, provided on an outer periphery of the shaft, and an inner peripheral wall surface of the rotor; and    a third oil pump provided above the second oil pump and formed by a spiral groove, provided on the outer periphery of the shaft, and an inner peripheral surface of the main bearing;    wherein the electromotive element is a bipolar permanent magnet electric motor including a permanent magnet built in a rotor iron core of the rotor.    
     
     
         11 . The hermetically sealed compressor as claimed in  claim 10 , wherein the main bearing does not intersect a plane containing one end of the rotor iron core adjacent the compressing element and lying generally perpendicular to a longitudinal axis of the main shaft.  
     
     
         12 . The hermetically sealed compressor as claimed in  claim 10 , further comprising an auxiliary shaft portion provided coaxially of the main shaft portion with the eccentric shaft portion intervening between it and the main shaft portion, and an auxiliary bearing for supporting the auxiliary shaft portion.  
     
     
         13 . The hermetically sealed compressor as claimed in  claim 10 , wherein the bipolar permanent magnet electric motor is a self-starting permanent magnet synchronous motor including a rotor having a plurality of conductor bars of a starter cage conductor in an outer periphery of the rotor iron core and also having a plurality of permanent magnets embedded within the rotor iron core.  
     
     
         14 . The hermetically sealed compressor as claimed in  claim 10 , wherein each of the permanent magnet is in the form of a rare earth magnet.