Brushless motor

摘要

A brushless motor comprises a circuit protecting case; a holder disposed on the case; a motor shaft rotatably held by the holder; a stator disposed about the holder and including a plurality of coils which surround the motor shaft; a yoke fixed to the motor shaft to rotate therewith and covering the stator with a given space therebetween; permanent magnets held by the yoke; a circuit substrate tightly held in the circuit protecting case; a drive circuit arranged on the circuit substrate, the drive circuit including a switching section which switches the path of current directed to the coils of the stator and a control section which controls a switching timing of the switching section, the switching section including a plurality of switching elements which generate a certain heat when operated. A partition wall is provided in the circuit protection case to partition the interior of the case into a first chamber to which the switching elements of the switching section are exposed and a second chamber to which the control section is exposed.