BRUSHLESS MOTOR

摘要

A brushless motor comprises a stator yoke plate made of a magnetic material, to the main surfaces of which are mounted first and second flexible printed circuit boards formed integrally and including a mutually connecting part. A plurality of driving coils is arranged annularly on the first flexible printed circuit board and a conductor pattern for a speed detecting coil is formed inside the driving coils. The first and second flexible printed circuit boards are provided with a central penetrated hole for receiving a rotor shaft. A tongue protudes generally inwardly from the periphery defining the penetrated hole and has a connecting conductor pattern thereon connected to the speed detecting coil. The tongue is folded back toward the side of the second flexible printed circuit board through the penetrated hole and the connecting conductor pattern is connected to the second flexible printed circuit board. An alternating signal induced in the speed detecting coil is withdrawn from the second flexible printed circuit board.