Portable electric cutter

A portable electric cutter comprising:

• a motor having a rotor and a stator;
• a circular saw blade driven to rotate by the motor;
• a base having an upper surface and a bottom surface which is opposite to the upper surface and is slidable on a material to be cut, and having an opening through which the circular saw blade protrudes downward from the bottom surface;
• a mechanism configured to adjust a cut-depth which is an amount of the circular saw blade protruding from the bottom surface of the base;
• a housing, disposed on the upper surface of the base, including a motor casing for accommodating the motor, the motor casing extending beyond an edge of the base in a first direction perpendicular to, and away from a circular surface of the circular saw blade;
• a fan which is disposed between the motor and the circular saw and which is driven to rotate by the motor to cool the motor by fan air generated by the rotation, the circular saw blade, the fan, and the motor being arranged in that order in the first direction;
• a driving circuit including switching elements for switching power supplied to the motor;
• a control circuit for controlling the driving circuit;
• and
• a circuit board on which one or both of the driving circuit and the control circuit are mounted, wherein:
• the housing includes a circuit board casing for accommodating the circuit board, the circuit board casing extending toward the circular saw blade, at least a part of the circuit board casing is disposed closer to the circular saw blade than any part of blades of the fan,
• the motor casing has motor cooling air vents,
• the circuit board casing has circuit board cooling air vents,
• the housing includes a space which is disposed between the stator and the circular saw blade, the space serving as an air flow path which communicates between the motor casing and the circuit board casing,
• at least a first part of the circuit board is disposed on a radially outer side of the fan wherein a direction orthogonal to a rotation axis of the fan is defined as a radial direction,
• at least a second part of the circuit board is disposed in a flow path of the fan air,
• the motor is a brushless motor,
• a rotation state detector for generating a signal in accordance with a rotation position of the motor is further provided,
• the control circuit receives the signal of the rotation state detector and transmits a signal for controlling the drive of the motor to the driving circuit,
• the motor has a rotator and a stator facing the rotator, the stator having an outer side opposite to a side facing the rotator, and
• the circuit board has a surface facing the outer side of the stator and extends in parallel to the rotation axis of the motor.

A portable electric cutter having a motor, the portable electric cutter comprising:

• a motor;
• a circular saw blade driven to rotate by the motor;
• a base having an upper surface and a bottom surface which is opposite to the upper surface and is slidable on a material to be cut, and having an opening through which the circular saw blade protrudes downward from the bottom surface;
• a housing, disposed on the upper surface of the base, including a motor casing for accommodating the motor, the motor casing extending beyond an edge of the base in a first direction perpendicular to, and away from a circular surface of the circular saw blade;
• a saw cover attached to the housing which is covering a part of the circular saw blade;
• a fan which is disposed between the motor and the saw cover and which is driven by the motor to generate an air flow for cooling the motor, the circular saw blade, the fan, and the motor casing being arranged in that order in the first direction;
• a driving circuit including switching elements for switching power supplied to the motor;
• a control circuit for controlling the driving circuit;
• and
• a power supply cord extending from the housing;
• a rectifier for rectifying an AC power from the power cord;
• and
• a circuit board on which the driving circuit, the control circuit, and the rectifier are mounted, wherein:
• the housing includes a circuit board casing for accommodating the circuit board, the circuit board casing extending toward the circular saw blade, at least a part of the circuit board casing is disposed closer to the circular saw blade than any part of blades of the fan,
• the motor casing has motor cooling air vents,
• the circuit board casing has circuit board cooling air vents,
• the circuit board is disposed in a flow path of the fan air,
• at least a part of the circuit board is disposed closer to the saw cover than any part of the blades of the fan,
• the motor is a brushless motor,
• a rotation state detector for generating a signal in accordance with a rotation position of the motor is further provided, and
• the control circuit receives the signal of the rotation state detector and transmits a signal for controlling the drive of the motor to the driving circuit.