CONTROL METHOD AND CONTROL UNIT FOR IMPACT TYPE SCREW FASTENING DEVICE

摘要

In an impact screw tightening device using an electric motor as the drivesource for rotation, tightening torque accuracy is improved and time requiredfor screw tightening is reduced. A control method for an impact screwtightening device using an electric motor as the drive source for rotation,where an electric current is intermittently supplied to the motor to drive androtate it so that torque applied to a load by the rotation of the motor ispulse-shaped on a time axis, and where, after the torque has reached targetapproach torque TQN which is a first set value, an electric current for eachbeat of the pulse of the torque is controlled so that an increment for eachbeat is less than that before the torque reaches the target approach torqueTQN.