| 摘要 |
Method for controlling the mechanical stress for a nut driver with the use of a nut driver and an assigned control device. In accordance with the invention, the tightening torque Tf of the torque transmitter of a nut driver is stored in a middle position of a fixed first rotational angle theta , contained in a middle region of the seat of a controlled screw on an object attached by screws to the final attached position of the screw. The motor of the nut driver is stopped in a position of a second rotational angle ( theta + alpha ) which is larger by a fixed value alpha than the first rotation angle. The motor of the nut driver is reversed at the second rotation angle ( theta + alpha ). A reaction torque Tr of the motor is stored at the position of the first rotation angle theta . The ratio of the fastening torque Tf to the axial force applied to the screw is calculated using a difference between the fastening torque Tf and the reaction torque Tr at the position of the first rotation angle theta . In order to fasten the screw with a stable required axial force, the motor is stopped at a fastening torque Ts which is obtained by multiplying a previous input target value FS of the required axial force by the calculated ratio.
|
