Axial Flux Machine Manufacture

Abstract

We describe a method of manufacturing a stator of an axial flux permanent magnet machine, the machine having a stator comprising a stator housing defining a chamber comprising a set of coils wound on respective stator bars and disposed circumferentially at intervals about an axis of the machine, and a rotor bearing a set of permanent magnets and mounted for rotation about said axis, and wherein said rotor and stator are spaced apart along said axis to define a gap therebetween in which magnetic flux in the machine is generally in an axial direction, the method comprising: providing first and second radial walls for said stator housing; providing inner and outer side walls for said stator housing; assembling said first and second radial walls and said inner and outer side walls around said set of coils to form a stator assembly, wherein said assembling further comprises: providing one or more collapsible elements between said side walls and one or both of said first and second radial walls; and attaching said side walls to said first and second radial walls, wherein said attaching comprises controlling one or both of a spacing and a degree of parallelism of said first and second radial walls by controlling the collapse of said one or more collapsible elements.

1 .- 19 . (canceled) 
     
     
         20 . An axial flux permanent magnet machine, the machine having a stator with a stator housing defining a chamber comprising a set of coils wound on respective stator bars and disposed circumferentially at intervals about an axis of the machine, and at least one rotor bearing a set of permanent magnets and mounted for rotation about said axis, and wherein said rotor and stator are spaced apart along said axis to define a gap therebetween in which magnetic flux in the machine is generally in an axial direction; wherein said stator housing further comprises one or more collapsed elements; and wherein said one or more collapsed elements comprise a collapsed polymer formation. 
     
     
         21 . An axial flux permanent magnet machine as claimed in  claim 20  wherein said collapsed elements comprise axially-collapsed portions of side or end walls of said stator housing. 
     
     
         22 . An axial flux permanent magnet machine as claimed in  claim 20 , the machine comprising two said rotors each bearing a set of permanent magnets, wherein said rotors and stator are spaced apart along said axis to define gaps therebetween in which magnetic flux in the machine is generally in an axial direction; wherein said rotors are disposed one to either side of said stator; and wherein one said rotor is mounted on the other said rotor. 
     
     
         23 . An axial flux permanent magnet machine as claimed in  claim 20 , further comprising a labyrinth seal between the stator and rotor. 
     
     
         24 . (canceled) 
     
     
         25 . (canceled)