AUTOMATIC SCREW TIGHTENING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide an automatic screw tightening machine capable of accurately tightening a screw with compensating variation of load current from an effect of motor intrinsic characteristics. SOLUTION: An automatic screw tightening machine includes a driver bit 3 driven by a motor 2 to rotate and engaging with a screw head, an encoder 2a detecting rotation angles of a drive shaft 2b of the motor 2, and a current detection part 10 detecting a load current of the motor 2. The automatic screw tightening machine includes current compensation data predetermined according to rotation angles detected by the encoder 2a and is provided with a control unit 4 compensating load current of the motor 2 detected by the current detection part 10 based on the current compensation data.