Sewing machine motor unit

Claim 1

A motor unit for sewing machines, comprising: a fixed structure of non-ferromagnetic material; a motor mounted within said fixed structure; a stop ring of non-ferromagnetic material; a drive shaft driven by the motor; a flywheel of ferromagnetic material connected to the drive shaft, said stop ring being of non-ferromagnetic material and being fixed to said flywheel; an output shaft, and an electromagnetically operated brake-clutch unit for controlling a connection between the drive shaft and the output shaft, said brake-clutch unit including: a clutch disc and a brake disc both of ferromagnetic material, said clutch disc and said brake disc being slidable axially on the output shaft and connected for rotation therewith, the clutch disc and the brake disc facing said flywheel and said fixed stop ring, respectively, a clutch winding and a brake winding carried by the fixed structure, the flywheel being interposed between the clutch winding and the clutch disc, and the fixed stop ring being interposed between the brake winding and the brake disc, ferromagnetic inserts mounted on said fixed structure, said ferromagnetic inserts defining annular cavities, the clutch winding and the brake winding being mounted in said annular cavities respectively on said ferromagnetic inserts carried by the fixed structure, and two annular friction linings for a frictional connection of the clutch disc and the brake disc with the flywheel and the fixed stop ring.