Capacity modulated scroll machine having one or more pin members movably disposed for restricting the radius of the orbiting scroll member

Abstract

A scroll-type machine is disclosed which is particularly well suited for use as a compressor in refrigeration and air conditioning systems and incorporates a unique arrangement for modulating the capacity thereof. In one group of embodiments the capacity of the scroll-type machine is modulated by relative axial movement between the scroll members so as to form a leakage path across the wrap tips and opposed end plates. In another group of embodiments, modulation is achieved by reducing the orbital radius of one of the scroll members to thereby form a leakage path across the flank surfaces of the wraps. In the second group, a plurality of pin members are moveable from a first and second positions. In a first position the plurality of pin members operably enable the scroll members to orbit and in a second position the pin members restrict the orbiting motion of the first scroll members. Both types of scroll separation may be accomplished in a time pulsed manner to thereby enable a full range of modulation with the duration of the loading and unloading periods being selected to maximize the efficiency of the overall system. A motor control arrangement is also disclosed which may be used with either of the modulation methods mentioned above to increase the efficiency of the motor during periods of reduced load. Additionally, either of the modulation arrangements mentioned above may be combined with a delayed suction form of capacity modulation with or without the motor control feature to thereby achieve better operating efficiency under certain conditions.

1. A scroll-type compressor comprising:
 a bearing housing; 
 a first scroll member movably supported on said bearing housing, said first scroll member including a first end plate and a first spiral wrap provided on one side thereof;  
 a second scroll member supported on said bearing housing, said second scroll member including a second end plate and a second spiral wrap provided on one side thereof;  
 a drive member;  
 a radially compliant coupling drivingly connecting said drive member to said first scroll member whereby said drive member operates to orbit said first scroll member with respect to said second scroll member at a first orbiting radius wherein said first and second spiral wraps are intermeshed and define sealed moving fluid pockets which decrease in size as they move from a radially outer position to a radially inward position;  
 a chamber;  
 a pin member movably disposed in said chamber, said pin member being movable from a first position at which said first scroll member orbits at said first orbiting radius and a second position in which said pin member restricts the orbiting radius of said first scroll member to a magnitude less than said first radius whereby leakage paths are formed between said moving fluid pockets; and  
 a drive system for reciprocating said pin between said first and second positions to thereby modulate the capacity of said compressor.  
 
     
     
       2. A scroll-type compressor as set forth in  claim 1  wherein said drive system reciprocates said pin in a time pulsed manner. 
     
     
       3. A scroll-type compressor as set forth in  claim 2  wherein said drive system operates to move said pin member to said first position for a first predetermined time period and to said second position for a second predetermined time period. 
     
     
       4. A scroll-type compressor as set forth in  claim 3  further comprising a sensor connected to a control module and operative to provide a signal thereto indicative of operating conditions, said control module being operative to control the duration of said first and second time periods to maximize the efficiency of said compressor for said operating conditions. 
     
     
       5. A scroll-type compressor as set forth in  claim 1  further including a plurality of chambers and a plurality of pin members movably disposed in each of said chambers, said drive system being operative to reciprocate each of said pin members between said first and second positions. 
     
     
       6. A scroll-type compressor as set forth in  claim 1  wherein said leakage path is sufficient to reduce the capacity of said scroll machine to substantially zero. 
     
     
       7. A scroll-type compressor as set forth in  claim 1  wherein said drive system is actuated by fluid pressure. 
     
     
       8. A scroll-type compressor as set forth in  claim 1  further comprising a motor for driving said drive member and a motor controller operative to vary an operating parameter of said motor in response to a signal indicative of movement of said pin into said second position to thereby improve the efficiency of said motor while the capacity of said compressor is reduced. 
     
     
       9. A scroll-type compressor as set forth in  claim 1  further comprising a passage opening into at least one of said moving fluid pockets and operative to vent said pocket to a lower pressure area of said compressor, a valve for opening and closing said passage and a control module to control operation of said valve. 
     
     
       10. A scroll-type compressor as set forth in  claim 9  wherein said control module includes at least one sensor operative to sense if said compressor is operating in an over-compression mode and to provide a signal indicative thereof to said control module, said control module being operative to actuate said valve in response to said signal to thereby reduce the compression ratio of said compressor. 
     
     
       11. A scroll-type compressor comprising:
 a hermetic shell;  
 a bearing housing supported within said shell;  
 a first scroll member movably supported on said bearing housing, said first scroll member including a first end plate and a first spiral wrap provided on one side thereof;  
 a second scroll member supported on said bearing housing, said second scroll member including a second end plate and a second spiral wrap provided on one side thereof;  
 a drive shaft rotatably supported by said bearing housing, said drive shaft including an eccentric;  
 a radially compliant coupling for drivingly connecting said drive shaft to said first scroll member whereby rotation of said drive shaft operates to orbit said first scroll member with respect to said second scroll member at a first orbiting radius with said first and second spiral wraps intermeshed and defining sealed moving fluid pockets which decrease in size as they move from a radially outer position to a radially inward position;  
 a plurality of chambers provided in spaced relationship in said bearing housing;  
 a plurality of pin members, one of said plurality of pin members being movably disposed in each of said chambers, said pin members being movable from a first position at which said first scroll member orbits at said first orbiting radius and a second position in which said pin members restrict the orbiting radius of said first scroll member to a magnitude less than said first radius whereby leakage paths are formed between said moving fluid pockets; and  
 a drive system for reciprocating said pins between said first and second positions in a time pulsed manner to thereby modulate the capacity of said compressor.  
 
     
     
       12. A scroll-type compressor as set forth in  claim 11  wherein each of said pin members extends through an opening in said first end plate. 
     
     
       13. A scroll-type compressor as set forth in  claim 11  wherein said drive system includes a fluid passage for selectively connecting said chambers to compressed fluid being discharged from said compressor to drive said pin members from said first position to said second position. 
     
     
       14. A scroll-type compressor as set forth in  claim 13  wherein each of said chambers includes a vent passage to vent said discharge pressure fluid into said shell. 
     
     
       15. A scroll-type compressor as set forth in  claim 13  wherein said drive system includes a valve for controlling fluid flow through said passage, said valve also being operative to place said chambers in fluid communication with a suction inlet of said compressor.