Screwing angle determining method for electrical screwdriver, involves dividing number of switching ripple by gear reduction of transmission between motor and screwdriver and by number of switching blades of motor, to determine angle

摘要

The method involves counting switching ripple at the level of rise of current and/or fall of voltage and/or increase of torque of a direct current motor. The number of switching ripples is divided by gear reduction of a transmission between the motor and a screwdriver and by a number of switching blades of the motor, to determine screwing angle. An independent claim is also included for an electrical screwdriver provided with a direct current motor.