Abstract: A torque transmission mechanism transmits a torque produced by a rotation of a driving shaft to an output shaft. A clutch mechanism is provided between a motor and the torque transmission mechanism. The torque transmission mechanism includes a magnet coupling including a driving magnet member coupled to the driving shaft side and a driven magnet member coupled to the output shaft side. The driving magnet member and the driven magnet member are arranged such that magnetic surfaces on each of which S-pole magnets and N-pole magnets are alternately arranged face other. The clutch mechanism transmits the torque produced by the rotation of the driving shaft to the driving magnet member but does not transmit a torque the driving magnet member receives from the driven magnet member to the driving shaft.

Abstract: A motor retainer is provided on an inner circumferential surface of a housing and retains an outer circumference of a motor unit. A rotation detector includes a rotating body attached to a motor shaft and a position detector that outputs a rotational position signal corresponding to a rotational position of the rotating body. A sensor substrate retainer is provided on the inner circumferential surface of the housing and retains the position detector at a position facing the rotating body.

Abstract: An electric power tool includes: a motor unit including a motor; a driving block for transmitting a rotational output of the motor to a front-end tool; and a rotation detector that detects an angle of rotation of the motor. The rotation detector includes a rotating body attached to a motor shaft and a position detector that outputs a rotational position signal corresponding to a rotational position of the rotating body. The rotating body includes an opening, and the motor shaft is press fitted and fixed to the opening of the rotating body.

Abstract: An electric power tool includes: a driving shaft that is rotated by a motor; an output shaft on which a front-end tool is attachable; and a torque transmission mechanism that transmits a torque produced by the rotation of the driving shaft to the output shaft. The torque transmission mechanism includes a magnet coupling including a driving magnet member coupled to a side of the driving shaft and a driven magnet member coupled to a side of the output shaft, and the driving magnet member and the driven magnet member are provided such that respective magnetic surfaces face each other, S-poles and N-poles being alternately arranged on each of the magnetic surfaces.

Abstract: An impact rotation tool including a drive source, an impact force generation unit that generates an impact force for converting power from the drive source to pulsed torque, a shaft that transmits the pulsed torque to a bit used to perform a tightening task, a torque measurement unit that measures torque applied to the shaft as measured torque, a rotation angle measurement unit that measures a rotation angle of the shaft, a tightening torque calculation unit that calculates an angular acceleration from the rotation angle to calculate a tightening torque based on the angular acceleration and the measured torque, and a controller that controls the drive source based on the tightening torque.

Abstract: An impact rotation tool includes an impact force generator that changes power of a drive source into pulsed torque to generate impact force. An output shaft transmits the pulsed torque to a bit based on the impact force. A torque measurement unit measures a shaft torque applied to the output shaft. An angular acceleration measurement unit measures angular acceleration of the output shaft. A moment of inertia calculator calculates moment of inertia of the bit coupled to the output shaft when rotated by the output shaft based on the shaft torque and the angular acceleration. A torque calculator calculates tightening torque based on the angular acceleration, the shaft torque, and the moment of inertia. A controller controls the drive source based on the tightening torque.

Abstract: A rotary impact tool comprises: a motor that is a rotation driving source; an impact generation device for generating a pulse impact by rotation of the motor and applying a rotational torque to an output shaft by the impact; a torque sensor for measuring the torque applied to the output shaft; and a control means for halting the motor when the torque measured by the torque sensor has reached a target torque having been set. The control means is configured to change an increased torque value for one impact according to the target torque having been set.

Abstract: An impact power tool includes an impact mechanism for applying a striking impact to an output shaft by using an output power of a motor. A strike detection unit detects the striking impact applied by the impact mechanism to obtain a striking timing and a striking speed detection unit calculates a striking speed from the striking timing obtained by the strike detection unit and a rotation angle of the motor obtained by a rotation angle detection unit. A control unit counts the number of striking impact detected by the strike detection unit and stops the motor if the number of striking impact reaches a predetermined strike number. The control unit is designed to correct the predetermined strike number when the striking speed obtained in the striking speed detection unit is equal to or lower than a specified striking speed.

Abstract: An impact rotation tool including a drive source, an impact force generation unit that generates an impact force for converting power from the drive source to pulsed torque, a shaft that transmits the pulsed torque to a bit used to perform a tightening task, a torque measurement unit that measures torque applied to the shaft as measured torque, a rotation angle measurement unit that measures a rotation angle of the shaft, a tightening torque calculation unit that calculates an angular acceleration from the rotation angle to calculate a tightening torque based on the angular acceleration and the measured torque, and a controller that controls the drive source based on the tightening torque.

Abstract: A rotary impact tool comprises: a motor that is a rotation driving source; an impact generation device for generating a pulse impact by rotation of the motor and applying a rotational torque to an output shaft by the impact; a torque sensor for measuring the torque applied to the output shaft; and a control means for halting the motor when the torque measured by the torque sensor has reached a target torque having been set. The control means is configured to change an increased torque value for one impact according to the target torque having been set.

Abstract: An impact power tool includes an impact mechanism for applying a striking impact to an output shaft by using an output power of a motor. A strike detection unit detects the striking impact applied by the impact mechanism to obtain a striking timing and a striking speed detection unit calculates a striking speed from the striking timing obtained by the strike detection unit and a rotation angle of the motor obtained by a rotation angle detection unit. A control unit counts the number of striking impact detected by the strike detection unit and stops the motor if the number of striking impact reaches a predetermined strike number. The control unit is designed to correct the predetermined strike number when the striking speed obtained in the striking speed detection unit is equal to or lower than a specified striking speed.

Abstract: A brushless motor has a stator, a rotor and a circuit board for controlling rotation of the rotor. The stator has iron cores and coils wound around the iron cores. Switching elements for turning on and off electric power to be supplied to the coils for the stator are mounted to the circuit board. A heat-radiating member is fixed to the iron cores.

Abstract: A brushless motor has a stator 6, a rotor 7 and a circuit board 4 for controlling rotation of the rotor 7. The stator 6 has iron cores 1 and coils 2 wound around the iron cores. Switching elements 3 for turning on and off electric power to be supplied to the coils 2 for the stator are mounted to the circuit board 4. A heat-radiating member 5 is fixed to the iron cores 1.