| 摘要 |
PURPOSE: To suppress cogging torque by setting a teeth peripheral direction forming space as 1 pitch, and forming a recessed groove in a position separated by a prescribed pitch from the teeth peripheral direction center part of a surface facing a rotor side of a flange part. CONSTITUTION: A brushless MOSFET1 is constituted by a motor driving permanent magnet 5 fixed to a rotary shaft 4 and by a stator 6 fixed so as to surround the permanent magnet 5 further to wind an excitation coil 6a, to form a rotor 7 of the rotary shaft 4 and the permanent magnet 5. A recessed groove 25 extended in an axial direction of the rotary shaft 4 is formed in a surface facing a side of the rotor 7 of a flange part 22. That is, each recessed groove 25 is a groove having a sectional shape of semicircular arc, to set a peripheral direction forming space of each tooth 20 as 1 pitch, to be formed in a position 1/4 pitch separated from the peripheral direction enter part of this tooth 20. |
