Patent ID: 6779612
Filing Date: 2004-08-24
Classification: B25F,H02K

Abstract:
A power tool comprising:a housing having a part defining a fan chamber and having outer and inner circumferential surfaces, the part of the housing being formed with at least one discharge window extending in a circumferential direction of the housing for allowing air to pass therethrough from the fan chamber to an atmosphere; a motor disposed in the housing and comprising an armature and a stator, the motor being rotatable in a first rotating direction and a second rotating direction opposite to the first rotating direction; and a cooling fan connected to the armature and rotatable together with the armature, the cooling fan being disposed in the fan chamber; and wherein the at least one discharge window is defined by at least a first wall portion and a second wall portion in opposition to the first wall portion in the circumferential direction, the first wall portion connecting the inner circumferential surface and the outer circumferential surface, and the a second wall portion connecting the inner circumferential surface and the outer circumferential surface, wherein at least a part of the first wall portion that is adjacent to the inner circumferential surface is inclined to the inner circumferential surface, and wherein at least a part of the second wall portion that is adjacent to the inner circumferential surface is inclined to the inner circumferential surface and substantially opposite to an inclination of the inclined part of the first wall portion, allowing a distance between the inclined part first wall portion and the inclined part of the second wall portion to be gradually reduced toward a radially outward direction of the housing.