Rotary stepping motor with laminated stator and rotor pole construction

Abstract

Abstract A multiphase rotary stepping motor of the type wherein each phase has a stator with a plurality of flux-conductive stator poles, a rotor with a plurality of flux-conductive rotor poles alignable with the stator poles, and a coil energized with appropriate timing to produce a magnetic field through said stator poles and rotor poles to bring them into alignment to thereby advance or retard the rotation of a shaft to which the rotors are attached. The rotor poles and stator poles are laminated from thin strips of flux-conductive material oriented so that at the confronting pole faces of rotor and stator, the longer dimension of the strip ends extends in a circumferential direction to permit high flux concentration at approaching or receding edges of the rotor and stator poles. The stator poles are constructed from a plurality of nesting strips of fluxconductive material assembled in two abutting C-shaped sections to form a rectangular loop having a gap therein to receive a rotor pole, the coil extending through the loop. The nesting strips in each C-shaped section have straight leg portions, graduated with increasing length toward the outside of the loop, joined by curved corners bent with a common radius of curvature. The leg length is graduated to provide a flush pole face at the gap and a flush abutting face for contact with the other C-shaped section, and the graduated increase in leg length is greater than the strip thickness in order to allow for minor deviations in length. Each C-shaped section is mounted between inner and outer mounting rings by being embedded therebetween with epoxy plastic. The rotor poles are constructed from a single strip of material wound spirally around a core member located axially between the inner rings of the stator. The strip is provided with wide portions forming the rotor poles, alternating with narrow portions between the wide portions. The narrow portions have graduated increases in circumferential length toward the outside of the spiral so that the wide portions are radially aligned and the rotor poles therefore extend radially. The spirally wound strip is mounted by embedding it and an outer flange of the core member with epoxy plastic.

Inventors

• 👤 I Cox

Bibliographic Details