Inductor device, in particular for hardening rolling tracks of an outer ring of a vehicle hub bearing unit

An inductor device, for hardening rolling tracks of an outer ring of a vehicle hub bearing unit, the inductor device comprising:

• at least one pair of blocks of electrically conducting material mechanically coupled to each other and electrically isolated from each other;
• at least one block of electrically insulating material mechanically connected to the blocks of electrically conducting material and supporting respective induction coils;
• a first hydraulic circuit comprising a block conduit portion formed as a plurality of holes passing through the blocks of electrically conducting material and a pipe stretch portion provided by respective pipe stretches made of electrically conducting material, wherein the pipe stretch portions are external to the blocks of electrically conducting material and mechanically connected in a fluid-tight manner on one end with the blocks of electrically conducting material and on the other end, the first hydraulic circuit providing flow of cooling fluid past the induction coils and providing electrical current to the induction coils;
• wherein the first hydraulic circuit comprises at least a first branch for feeding a cooling fluid to the induction coils and at least a second branch for removing the cooling fluid from the induction coils, the first branch utilizing at least one hole of the plurality of holes passing through the blocks;
• wherein the first branch and the second branch create an electric circuit with the induction coils,
• wherein, in combination:
• i) the first branch hydraulically connects all the induction coils in parallel and mechanically in sequence to each other;
• ii) the second branch hydraulically connects only a first induction coil of the induction coils with a first return outlet of the first hydraulic circuit;
• and
• iii) the first hydraulic circuit comprises at least a third branch for each induction coil in addition to the first induction coil, the at least a third branch comprising a second return outlet separated from the first outlet and being hydraulically connected with only one single induction coil other than the first induction coil.