| 摘要 |
PROBLEM TO BE SOLVED: To allow an accurate fastening torque to be managed by efficiently performing fastening while reducing reaction of a fastening torque even when fastening a soft body, in a screw fastening method using an electric motor as a drive source.SOLUTION: High-speed speed control of causing an output shaft to rotate at high speed by a continuous fastening torque is performed until fastening is started and a fastening torque T reaches a seating torque T, and thereafter low-speed speed control of causing the output shaft to rotate at low speed by the continuous fastening torque is performed until the fastening torque T reaches a switching torque T. After the fastening torque T reaches the switching torque T, pulse control of cyclically increasing and decreasing the fastening torque T is performed, and fastening is performed to a stipulated torque T. Thus, fastening time to a seating point S is shortened, and compression and deformation from the seating point S to a switching point SW when fastening a soft body are efficiently performed. After the switching point SW is reached, fastening is performed by the pulse control, and the reaction of the fastening torque is reduced. |
