Soft start compressor clutch

An electromagnetic clutch for an air conditioning compressor housed in a compressor housing having a drive shaft extending from the housing and being rotatable about an axis of rotation, the clutch comprising:

• a generally cylindrical driven member having an axis of rotation and a peripheral annular first frictional surface, said driven member having a first axial end and a second axial end;
• an annular pulley extending about said driven member and having an axis of rotation coaxial with said driven member axis of rotation, said pulley having an annular second frictional surface positioned radially adjacent said first frictional surface to form an annular space therebetween;
• a plurality of reservoirs, each of said plurality of reservoirs in fluid communication with said annular space, at least one of said plurality of reservoirs disposed adjacent the first axial end of said driven member and another of said plurality of reservoirs disposed adjacent the second axial end of said driven member;
• a quantity of flowable magnetic material provided in said annular space and said plurality of reservoirs;
• a magnetic coil positioned adjacent said annular space;
• and
• a control means connected to said magnetic coil for supplying electrical power from a power supply to energize said magnetic coil whereby when said driven member is attached to a shaft of a compressor extending from a compressor housing, said pulley is rotatably mounted on the compressor housing and said magnetic coil is fixed to the compressor housing, said pulley can be rotated without rotating said driven member, and when said control means applies electrical power to said magnetic coil, magnetic flux is created in said annular space polarizing said magnetic material and frictionally coupling said first and second frictional surfaces to cause said driven member to rotate with said pulley.

An air conditioning compressor assembly of the type for compressing a refrigerant fluid, said assembly comprising:

• a fluid pump in a housing having a drive shaft rotatably supported about a central axis and operatively connected to said fluid pump, a portion of said drive shaft extending from said housing;
• a generally circular driven member fixedly secured to said drive shaft adjacent said housing, said driven member having a peripheral annular first clutch surface including at least one annular groove formed therein;
• a pulley rotatably supported on said housing independently of said drive shaft for rotation about said central axis and including an annular second clutch surface adjacent said first clutch surface forming an annular space therebetween;
• a plurality of reservoirs, each of said plurality of reservoirs in fluid communication with said annular space;
• a quantity of a magnetic material provided in said annular space and said plurality of reservoirs;
• a magnetic coil fixedly mounted on said housing adjacent said annular space;
• and
• a control means operable to apply electrical power to said magnetic coil to create magnetic flux across said annular space to energize said magnetic material and cause said driven member to rotate with said pulley.