Patent ID: 10348158

Abstract:
A power tool (1) includes a brushless motor (8) having a stator (9) and a rotor (10). The stator (9) includes: a tubular stator core (60); front and rear insulators (61, 62) fixed to the stator core; and coils (64), which are wound around a plurality of teeth (63) on the stator core. The rotor (10) includes: a rotor core (67) disposed within the stator; a rotary shaft (11) fixed to the rotor core; and one or more permanent magnets (68) fixed to the rotor core. A sensor-circuit board (65) detects the position(s) of the permanent magnet(s) and is fixed to the stator. One or more notched parts (91) is/are formed, in an outer circumference of the sensor-circuit board, between circumferentially-adjacent teeth in an axial direction of the stator. The notch part(s) allow(s) air for cooling the brushless motor to pass more easily through the interior of the stator.