| 摘要 |
PROBLEM TO BE SOLVED: To improve space efficiency (output per size) of an SR motor, which requires no permanent magnet.SOLUTION: A DC brushless motor 1 for performing an SR operation comprises: a stator 2 including excitation coils 31 and 32; and a rotor 4 arranged coaxially with the stator 2. The stator 2 is formed into a substantially E-shaped form when viewed as a half cross section in a Z-axis direction, to have a two-layer structure. Among three parallel parts 21, 22 and 23 of the E-shaped portion, the top and bottom parallel parts have a plurality of protrusions 212 and 232 repeatedly formed in a circumferential direction so as to serve as magnetic poles and the middle parallel part is formed in an annular shape, and the magnetic poles (the protrusions 212 and 232) are given in the same number and arranged in a phase-shifting manner with each other, so as to enable the DC brushless motor 1 to start. Since the rotor 4 includes no magnet, the cost thereof is low, and there is no problem related to thermal demagnetization of a magnet. Furthermore, space efficiency can be improved since a magnetic circuit for two phases always contributes to generation of torque. |
