Abstract: An electric tool includes a motor. The motor includes a stator core and a rotor. The rotor rotates with respect to the stator core. The rotor includes: a rotor core having a circular cylindrical shape; a plurality of permanent magnets; and an output shaft. The output shaft is held inside the rotor core. The plurality of permanent magnets are arranged as spokes around a center of the rotor core.

Abstract: An electric tool includes a motor. The motor includes a stator core and a rotor. The rotor rotates with respect to the stator core. The rotor includes: a rotor core having a circular cylindrical shape; a plurality of permanent magnets; and an output shaft. The output shaft is held inside the rotor core. The plurality of permanent magnets are arranged as spokes around a center of the rotor core.

Abstract: An electric tool includes a motor. The motor includes a stator core and a rotor. The rotor has an output shaft and rotates with respect to the stator core. The stator core includes: an inner cylindrical portion having a circular cylindrical shape; and a plurality of teeth. Inside the inner cylindrical portion, the rotor is arranged. Each of the plurality of teeth includes a body portion and a tip piece. The body portion protrudes outward from the inner cylindrical portion along a radius of the inner cylindrical portion. The tip piece extends, from a tip part of the body portion, in a direction intersecting with a direction in which the body portion protrudes.

Abstract: A control circuit for an electric tool according to the present invention, includes a permanent magnet synchronous motor, a plurality of switching elements, and a PWM inverter circuit that drives the permanent magnet synchronous motor. The control circuit includes a current detector that detects a current flowing through the PWM inverter circuit. When braking the permanent magnet synchronous motor, the control circuit limits a current flowing through the permanent magnet synchronous motor and the PWM inverter circuit, to a predetermined current limit value. At the same time, by switching low-side switching elements or high-side switching elements of the PWM inverter circuit, the control circuit boosts an induced electromotive voltage of the permanent magnet synchronous motor, and regenerates a regenerative current to the battery.

Abstract: A power converting apparatus is provided with an inverter circuit, an output short-circuiting circuit, and a control circuit. The inverter circuit comprises a first inverter switch and a second inverter switch. The output short-circuiting circuit comprises a first short-circuiting switch configured so as to short-circuit a power supply line that outputs a first polarity voltage, out of a pair of power supply lines, and a second short-circuiting switch configured so as to short-circuit a power supply line that outputs a second polarity voltage, out of the pair of power supply lines. Upon switching the polarity from the first polarity to the second polarity, the control circuit turns off the first short-circuiting switch before the timing whereby the second inverter switch is turned on.

Abstract: Provided is a contactless power receiving unit which has a simple configuration, and which is capable of generating constant induced electromotive force regardless of the orientation of a power receiving coil. Multiple power receiving coils are arranged to form certain relative angles to one another in a parallel magnetic field generated by a power supply unit. A rectifier circuit is connected to each power receiving coil. An adder circuit is configured to add DC power obtained, through the rectifier circuits, from the multiple power receiving coils, and to output resultant DC power of the addition.

Abstract: Provided is a contactless power receiving unit which has a simple configuration, and which is capable of generating constant induced electromotive force regardless of the orientation of a power receiving coil. Multiple power receiving coils are arranged to form certain relative angles to one another in a parallel magnetic field generated by a power supply unit. A rectifier circuit is connected to each power receiving coil. An adder circuit is configured to add DC power obtained, through the rectifier circuits, from the multiple power receiving coils, and to output resultant DC power of the addition.