| 摘要 |
PROBLEM TO BE SOLVED: To obtain a brushless DC motor in which a dynamic characteristic is enhanced, by a method wherein a base and a shaft are coupled by a bearing system so as to be rotatable and an idle-movement suppression means is controlled according to the signal of a sensing part in bearing system. SOLUTION: An idle-movement suppression means 19 is installed between the inside wall and the outside wall of a bearing 11 which constitutes a bearing system. The idle-movement suppression means 19 is used in such a way that rotor 17 is not levitated to the axial direction by a centrifugal force in a process in which the rotor 17 is turned. An electromagnet coil 20 which constitutes the idle-movement suppression means 19 is wound, in a definite amount, on a groove 21 which is formed on the bearing 11. When an idle-movement amount due to the levitation of the rotor 17 is sensed by a sensing part 22, the idle-movement suppression means 19 is operated. The sensing part 22 is constituted of an induction coil 23 which is wound on the bearing 11, and an analog PID controller which is called an operational amplifier or the like is used. Consequently, an induced current is generated by the induction coil 23 by the displacement amount of the rotor 17, the induced current is applied to an amplifier 24 and a controller 25, and the idle-movement suppression means 29 is controlled finally. |
