Stator for an axial flux machine and method for producing the same

A yokeless stator for an axial flux electrical machine, comprising:

• a housing comprising a circumferential portion;
• a plurality of discrete stator teeth arranged within the circumferential portion, each discrete stator tooth comprising a ferromagnetic material and an electrical winding wound around said ferromagnetic material;
• the housing further comprising a plurality of elongated portions extending in a radially inward direction from said circumferential portion,
• the elongated portions having a proximal end being mechanically connected to the circumferential portion and being in thermal contact with said circumferential portion, and having a distal portion or distal end being physically located between the electrical windings of adjacent stator teeth;
• an electrically isolating filling material filling empty space within said circumferential portion between said plurality of stator teeth and said plurality of elongated portions,
• wherein said circumferential portion of said housing is made of a first non-ferromagnetic material and said elongated portions are made of a second non-ferromagnetic material,
• wherein said housing comprises a laminated structure, said laminated structure comprising at least some of said plurality of inwardly directed elongated portions, and
• wherein an inner wall of said circumferential portion of said housing comprises a plurality of notches or grooves for mounting said plurality of elongated portions.

A method of producing a yokeless stator for an axial flux electrical machine, comprising the steps of:

• a) providing a stator housing comprising a circumferential portion made of a first non-ferromagnetic material and a plurality of elongated portions made of a second non-ferromagnetic material and extending from said circumferential portion in a radially inward direction,
• the elongated portions having a proximal end which is mechanically connected to the circumferential portion and is in thermal contact with said circumferential portion,
• the elongated portions being adapted for defining a plurality of cavities for receiving a plurality of discrete stator teeth;
• at least some of said elongated portions being comprised in a laminated structure of said stator housing,
• b) arranging a plurality of discrete stator teeth in said plurality of cavities, each discrete stator tooth comprising a ferromagnetic material or ferromagnetic core and an electrical winding wound around said ferromagnetic material or ferromagnetic core;
• c) increasing a temperature of the arrangement to a temperature in the range from 50° C. to 250° C., and while maintaining this temperature, filling empty space within said circumferential portion with an electrically isolating filling material;
• d) allowing the filling material to harden and/or cure.