Patent ID: 7755229

Claim:
A hybrid step motor, comprising: a stator, a rotor assembly, a magnet and a mandrel, wherein: the stator is formed with a stator outer diameter having a magnetic space, in a periphery of the magnetic space is provided a plurality of stator poles that are spaced at intervals, inner peripheries of the stator poles form a stator inner diameter, a proportion of the stator outer diameter to the stator inner diameter is 1:0.475 to 1:0.6; the rotor assembly comprises a first rotor and a second rotor which are made of silicon steel sheets and are round-shaped, the rotor assembly is formed with a rotor outer diameter, the first rotor is formed with a first rotor thickness along a axial direction, the second rotor is formed with a second rotor thickness along the axial direction, the first and second rotors are mounted on the mandrel and are disposed in the magnetic space of the stator, a proportion of the stator outer diameter to the rotor outer diameter is 1:0.5125 to 1:0.5875; the magnet is formed with a magnet outer diameter and is formed with a magnet thickness along the axial direction, the magnet is mounted on the mandrel and is located between the first rotor and the second rotor; a proportion of the first rotor thickness to the magnet thickness to the second rotor thickness is 0.236:0.09:0.236, an error is ±0.0375 mm, a proportion of the rotor outer diameter to the magnet outer diameter is 0.54:0.45, an error is ±0.025 mm; the mandrel is provided for mounting the rotor assembly and the magnet, and making the rotor assembly and the magnet receive in the magnetic space of the stator.