Magnetorheological fan coupling

Abstract

A magnetorheological fan coupling ( 10 ) having a fan-drive subassembly ( 12 ), an electromagnet subassembly ( 14 ), and a magnetic medium ( 16 ). The fan-drive subassembly ( 12 ) includes an output member ( 22 ) and an input member ( 20 ) rotatably mounted around the output member ( 22 ) with the magnetic medium ( 16 ) therebetween. The magnetic medium ( 16 ) has a shear stress that can be adjusted by a magnetic flux ( 24 ) for transferring torque between the input member ( 20 ) and the output member ( 22 ). The electromagnet subassembly ( 14 ) includes a stationary electromagnet coil ( 62 ) for adjusting the shear stress of the magnetic medium ( 16 ) and regulating a torque transferred between the input member ( 20 ) and the output member ( 22 ).

1 . A magnetic coupling comprising:
 an electromagnet;   a drivable input member rotatably mounted proximate said electromagnet;   an output member rotatably mounted proximate said electromagnet such that said input member is rotatably mounted about said output member; and   a magnetic medium having an associated shear stress and disposed within a substantially closed and continuous work chamber defined between said input member and said output member;   wherein said electromagnet is activatable to generate a magnetic field and thereby adjust said shear stress of said magnetic medium so as to regulate the transfer of any torque from said input member and to said output member; and   wherein said input member has a plurality of external fins for producing a flow of air that cools said magnetic coupling when said input member is driven to rotate.   
   
   
       2 . A magnetic coupling as set forth in  claim 1 , wherein said input member includes a pulley by which said input member is drivable by a belt. 
   
   
       3 . A magnetic coupling as set forth in  claim 2 , wherein said input member is structurally adapted so that said pulley is selectively removable therefrom and also installable thereon. 
   
   
       4 . A magnetic coupling as set forth in  claim 1 , wherein said input member is structurally adapted for having any one of a series of different-sized pulleys selectively installed thereon for use in one of a plurality of different-sized vehicles. 
   
   
       5 . A magnetic coupling as set forth in  claim 1 , wherein said output member is structurally adapted for having a fan coupled thereto. 
   
   
       6 . A magnetic coupling as set forth in  claim 1 , wherein said magnetic medium comprises a magnetorheological fluid. 
   
   
       7 . A magnetic coupling as set forth in  claim 1 , wherein said magnetic medium comprises a magnetic powder. 
   
   
       8 . A magnetic coupling as set forth in  claim 1 , said magnetic coupling further comprising a controller coupled to said electromagnet. 
   
   
       9 . A magnetic coupling as set forth in  claim 8 , said magnetic coupling further comprising a sensor that is coupled to said controller and operable to sense temperature. 
   
   
       10 . A magnetic coupling as set forth in  claim 8 , said magnetic coupling further comprising a sensor that is coupled to said controller and operable to sense any rotational-speed differential between said input member and said output member. 
   
   
       11 . A magnetic coupling for a fan, said magnetic coupling comprising:
 a controller;   an activatable electromagnet coupled to said controller;   a drivable input member rotatably mounted proximate said electromagnet;   an output member rotatably mounted proximate said electromagnet such that said input member is rotatably mounted about said output member; and   a magnetic medium having an associated shear stress and disposed within a substantially closed and continuous work chamber defined between said input member and said output member;   wherein said controller is operable to activate said electromagnet so as to generate a magnetic field and thereby controllably adjust said shear stress of said magnetic medium for regulating the transfer of any torque from said input member and to said output member;   wherein said input member has a plurality of external fins for producing a flow of air that cools said magnetic coupling when said input member is driven to rotate; and   wherein said output member is structurally adapted for having said fan coupled thereto.   
   
   
       12 . A magnetic coupling as set forth in  claim 11 , wherein said input member includes a pulley by which said input member is drivable by a belt. 
   
   
       13 . A magnetic coupling as set forth in  claim 11 , wherein said magnetic medium comprises a magnetorheological fluid. 
   
   
       14 . A magnetic coupling as set forth in  claim 11 , wherein said magnetic medium comprises a magnetic powder. 
   
   
       15 . A magnetic coupling as set forth in  claim 11 , said magnetic coupling further comprising a sensor that is coupled to said controller and operable to sense any rotational-speed differential between said input member and said output member. 
   
   
       16 . A magnetic coupling for a fan, said magnetic coupling comprising:
 a controller;   an activatable electromagnet coupled to said controller;   a drivable input member rotatably mounted proximate said electromagnet;   an output member rotatably mounted proximate said electromagnet such that said input member is rotatably mounted about said output member; and   a magnetic medium having an associated field-sensitive viscosity and disposed within a substantially closed and continuous work chamber defined between said input member and said output member;   wherein said controller is operable to activate said electromagnet so as to generate a magnetic field and thereby controllably adjust said viscosity of said magnetic medium for regulating the transfer of any torque from said input member and to said output member;   wherein said input member has a plurality of external fins for producing a flow of air that cools said magnetic coupling when said input member is driven to rotate; and   wherein said output member is structurally adapted for having said fan coupled thereto.   
   
   
       17 . A magnetic coupling as set forth in  claim 16 , wherein said input member includes a pulley by which said input member is drivable by a belt. 
   
   
       18 . A magnetic coupling as set forth in  claim 16 , wherein said magnetic medium comprises a magnetorheological fluid. 
   
   
       19 . A magnetic coupling as set forth in  claim 16 , wherein said magnetic medium comprises a magnetic powder. 
   
   
       20 . A magnetic coupling as set forth in  claim 16 , said magnetic coupling further comprising a sensor that is coupled to said controller and operable to sense any rotational-speed differential between said input member and said output member.