High Precision Control Method of Pre-Tightening Force for Threaded Connection of Joining-Separation Mechanism in Aircraft

摘要

In order to ensure the reliability of threaded connection of joining-separation mechanism in aircraft, high precision control of pre-tightening force is needed in the process of assembling and adjustment. In view of the precision and applicability of existing control methods, a high precision control method, i.e., torque-displacement method is proposed in this paper. In this method, a small part of pre-tightening force is achieved by using torque wrench to eliminate the gap between contact surfaces, while the rest part is achieved by using common wrench, according to the theoretical displacement at the end of bolt produced by pretightening force. The bolt applied in a typical joining-separation mechanism in aircraft is used as a case study to explain how this method works. The theoretical displacement at the end of the bolt is calculated by finite element method, considering material nonlinearity, contact problem and mesh generation which are related to the numerical accuracy. In this case, high pr ecision laser displacement sensor is used to monitor the displacement of the bolt, and high precision strain gauge is used to valuate the control precision of pre-tightening force. The experimental results show that the proposed torque-displacement control method of pre-tightening force is of a high control precision of ±4%.