Patent ID: 8816544
Filing Date: 2014-08-26
Classification: B24B,B25F,H02K

Abstract:
1. An electric power tool comprising: a housing defining an axial direction including a grip portion that extends in the axial direction, the housing having: an inner surface; one end portion formed with an air outlet port; and another end portion formed with an air inlet port, an air passage being defined in the housing from the air inlet port to the air outlet port; a brushless motor accommodated in the grip portion and having a drive shaft; and a motor driver circuit accommodated in the grip portion and configured to drive the brushless motor; wherein the motor driver circuit includes a switching circuit board on which a switching element is surface-mounted, the switching circuit board extending in a direction substantially parallel to the extending direction of the grip portion; wherein the housing has a guide portion protruding toward the switching circuit board from the inner surface, the guide portion being integral with the housing and having a guide surface extending in a direction parallel to the switching circuit board; wherein the air passage includes a gap defined between the switching circuit board and the guide surface, the air passage being configured to direct a cooling air flow through the gap.