Variable capacity compressor with line-start brushless permanent magnet motor

Abstract

A variable capacity compressor assembly ( 20 ) configured for variable capacity modulation includes a housing ( 30 ), with a compressing mechanism ( 22 ) and a driving mechanism ( 24 ) disposed within the housing. The compressing mechanism includes compressing members ( 54, 56 ) that are shiftable relative to one another between loaded and unloaded states. The driving mechanism includes a line-start brushless permanent magnet motor ( 26 ). The line-start brushless permanent magnet motor includes a plurality of permanent magnets ( 102 ) that are mounted on, and extend generally axially along, a rotor core body ( 90 ) of the motor. Using the motor may reduce manufacture cost, maintain conveniently, and increase reliability.

What is claimed is: 
     
         1 . A variable capacity compressor assembly configured to provide variable capacity modulation, said compressor assembly comprising:
 a housing;   a compressing mechanism disposed within the housing and including first and second mechanical elements,   said mechanical elements being shiftable relative to one another between a loaded state and an unloaded state; and   a driving mechanism disposed within the housing and drivingly engaging at least one of the mechanical elements for causing the mechanical elements to move relative to one another, said driving mechanism including a line-start brushless permanent magnet motor,   said motor including a stator and a rotor rotatable about an axis and spaced away from the stator,   said rotor including a rotor core body and a plurality of permanent magnets mounted on the rotor core body,   said permanent magnets extending generally axially along the rotor core body.   
     
     
         2 . The variable capacity compressor assembly as claimed in  claim 1 , said mechanical elements comprising scroll members. 
     
     
         3 . The variable capacity compressor assembly as claimed in  claim 2 ,
 said driving mechanism further including a drive shaft configured to rotate with the rotor,   said drive shaft being operably coupled with one of the scroll members for causing the one of the scroll members to move in a generally orbital relationship relative to the other of the scroll members.   
     
     
         4 . The variable capacity compressor assembly as claimed in  claim 3 , said scroll members being shiftable generally axially relative to one another between the loaded and unloaded states. 
     
     
         5 . The variable capacity compressor assembly as claimed in  claim 4 , said housing comprising a hermetic shell defining a substantially enclosed space. 
     
     
         6 . The variable capacity compressor assembly as claimed in  claim 1 ,
 said permanent magnets being received within the rotor core body,   said rotor core body comprising a plurality of axially stacked rotor laminations,   at least one of said rotor laminations being disposed in contact with the plurality of permanent magnets to retain the same in place.   
     
     
         7 . The variable capacity compressor assembly as claimed in  claim 6 ,
 said permanent magnets being disposed generally parallel to the axis,   said permanent magnets being disposed substantially adjacent a radially outer periphery of the rotor core body.   
     
     
         8 . The variable capacity compressor assembly as claimed in  claim 7 ,
 said rotor assembly further including a plurality of circumferentially spaced axial bars disposed adjacent the radially outer periphery of the rotor core body to cooperatively define at least a portion thereof.   
     
     
         9 . The variable capacity compressor assembly as claimed in  claim 8 ,
 said rotor assembly including four substantially equally-sized permanent magnets,   said permanent magnets being arranged in two pairs, with each of the pairs of magnets being symmetrical to the other of the pairs of magnets with respect to the axis.   
     
     
         10 . The variable capacity compressor assembly as claimed in  claim 9 ,
 said mechanical elements comprising scroll members shiftable generally axially relative to one another between the loaded and unloaded states,   said motor assembly defining a single-speed, three-phase motor.   
     
     
         11 . The variable capacity compressor assembly as claimed in  claim 1 ,
 said motor assembly defining a single-speed motor.   
     
     
         12 . The variable capacity compressor assembly as claimed in  claim 11 , said motor assembly defining a three-phase motor. 
     
     
         13 . The variable capacity compressor assembly as claimed in  claim 1 ,
 said stator including a stator core body presenting a plurality of circumferentially spaced axial slots and defining a central bore for receiving the rotor,   said stator further including electrically conductive winding coils received within and distributed generally across multiple ones of the axial slots of the stator core body, said winding coils comprising aluminum.   
     
     
         14 . The variable capacity compressor assembly as claimed in  claim 1 , said permanent magnets comprising neodymium. 
     
     
         15 . The variable capacity compressor assembly as claimed in  claim 1 , said compressing mechanism comprising a piston and cylinder assembly, and said mechanical elements including a valve to block suction gas to said piston and cylinder assembly. 
     
     
         16 . The variable capacity compressor assembly as claimed in  claim 1 , said compressing mechanism comprising scroll members and said mechanical elements including a valve to release gas from an intermediate chamber of said scroll members to a suction chamber within said housing. 
     
     
         17 . The variable capacity compressor assembly as claimed in  claim 1 , said compressing mechanism comprising a rotary vane and a compression rotor and said mechanical elements including a three-way valve to alternately apply suction gas and discharge gas to said rotary vane to bias said rotary vane against and away from said compression rotor. 
     
     
         18 . In a variable capacity compressor assembly configured to provide variable capacity modulation including a compressing mechanism disposed within a housing with first and second mechanical elements shiftable relative to one another between a loaded state and an unloaded state, and a driving mechanism disposed within the housing for drivingly engaging one of the mechanical elements to cause the mechanical elements to move relative to one another, wherein the improvement comprises combining the shiftable mechanical elements with a single-speed, line-start brushless permanent magnet motor operable to drive the one of the mechanical elements,
 said motor including a stator and a rotor rotatable about an axis and spaced away from the stator,   said rotor including a rotor core body and a plurality of permanent magnets mounted on the rotor core body,   said permanent magnets extending generally axially along the rotor core body.   
     
     
         19 . In the variable capacity compressor assembly configured to provide variable capacity modulation as claimed in  claim 18 ,
 said mechanical elements comprising scroll members,   said driving mechanism further including a drive shaft configured to rotate with the rotor,   said drive shaft being operably coupled with one of the scroll members for causing the one of the scroll members to move in a generally orbital relationship relative to the other of the scroll members.   
     
     
         20 . In the variable capacity compressor assembly configured to provide variable capacity modulation as claimed in  claim 19 ,
 said permanent magnets being received within the rotor core body,   said rotor core body comprising a plurality of axially stacked rotor laminations,   at least one of said rotor laminations being disposed in contact with the plurality of permanent magnets to retain the same in place.   
     
     
         21 . In the variable capacity compressor assembly as claimed in  claim 18 , said compressing mechanism comprising a piston and cylinder assembly, and said mechanical elements including a valve to block suction gas to said piston and cylinder assembly. 
     
     
         22 . The variable capacity compressor assembly as claimed in  claim 18 , said compressing mechanism comprising scroll members and said mechanical elements including a valve to release gas from an intermediate chamber of said scroll members to a suction chamber within said housing. 
     
     
         23 . The variable capacity compressor assembly as claimed in  claim 18 , said compressing mechanism comprising a rotary vane and a compression rotor and said mechanical elements including a three-way valve to alternately apply suction gas and discharge gas to said rotary vane to bias said rotary vane against and away from said compression rotor. 
     
     
         24 . A method of delivering increased compressor efficiency at lower incremental cost within a variable capacity compressor assembly configured to provide variable capacity modulation, wherein the compressor includes first and second scroll members generally axially shiftable relative to one another between a loaded state and an unloaded state, said method comprising:
 driving one of the scroll members with a single-speed, line-start brushless permanent magnet motor, such that the driven scroll member moves in a generally orbital relationship relative to the other scroll member to thereby compress a working fluid when the scrolls are in the loaded state; and   shifting the scroll members into the unloaded state during continuous operation of the single-speed motor to thereby efficiently modulate capacity of the compressor without the expense of a complex drive unit to vary motor speed.   
     
     
         25 . The increased compressor efficiency delivering method of  claim 24 ,
 said motor including a stator and a rotor rotatable about an axis and spaced away from the stator,   said rotor including a rotor core body and a plurality of permanent magnets mounted on the rotor core body,   said permanent magnets extending generally axially along the rotor core body.   
     
     
         26 . The increased compressor efficiency delivering method of  claim 25 , said scroll members and said single-speed motor being disposed within a hermetic shell defining a substantially enclosed space.