Abstract: An electric multiphase motor with a closed ring housing and a pole piece star which is inserted therein after being wound from the outside, the pole piece star having axially integral pole pieces which are arranged in star-like fashion around a hollow cylinder and inserted therein in which great strength of the pole star is achieved while at the same time ensuring good electrical data by inserting the radially inner ends of the pole pieces into the hollow cylinder as individual parts up to the bore of the hollow cylinder so that after the assembly of the motor no further finishing operations are required and welding the radially outer ends of the pole pieces to the inside to the surrounding ring housing by electron beam welding starting at the outer circumference of the ring housing.

Abstract: An improved stator for an electric polyphase motor, particularly a stepping motor, is disclosed. The stator includes a pole piece star having axially integral pole pieces arranged in star-like fashion around the hollow cylinder with the radial inner ends of the pole pieces located in the hollow cylinder and protruding a pre-determined small distance beyond the inner wall of the hollow cylinder. Thus, the hollow cylinder is set back from the radial inner edges of the pole pieces to provide minimum sized air gaps without requiring finishing operations on the cylinder after the motor is assembled. The radial outer ends of the pole pieces are welded to the surrounding ring housing by laser beam welding. The hollow cylinder is disclosed as an injection-molded part with the pole pieces molded therein simultaneous with the injection molding. A core mold for the cylinder is also disclosed.

Abstract: An improved multi-section rotor stack for a squirrel-cage sliding rotor type motor which includes a laminated stator stack, a laminated rotor stack, an axial shorting ring disposed on at least one end thereof, and an intermediate shorting ring interposed in the rotor stack at the other end thereof. The intermediate ring divides the rotor stack into a pair of sections of unequal length disposed respectively between the intermediate and axial shorting rings, and between the intermediate ring and the opposing end of the rotor stack relative to the axial shorting ring. The latter of the sections is shorter in axial length then the other and has a radial diameter which is greater, and increases the resultant axial force produced by the motor.