楔形螺纹连接扭拉关系理论分析及拧紧特性

Wedge self-locking nut is a widely used anti-loosening structure. However, currently, there is a lack of theoretical analysis on the torsion-tension relationship and tightening characteristics of wedge threaded connection, which leads to the lack of theoretical guidance on the installation of wedge self-locking nut. The theoretical formula of torsion-tension relationship during the tightening process of wedge self-locking nut is established and verified for the first time, and the influencing factors of the tightening characteristics of wedge threaded connection are analyzed. First, the complex geometry of the wedge threaded surface is considered, the local coordinate system of any region on the wedge thread surface is constructed, and the plane equation, tangential vector and normal vector of any wedge area are obtained by coordinate transformation. On this basis, the theoretical formula of the torsion-tension relationship of wedge self-locking nut is established. Second, the accurate finite element model of wedge threaded connection is established and the actual tightening process is simulated. The different discrete data points of torque-tension are obtained by changing different friction coefficients, wedge angles and pitches. These data points of torque-tension are then compared with the relationship curve of torque-tension described by the theoretical formula, based on which the reliability of the theoretical formula of torque-preload is verified. At the same time, two typical wedge self-locking nuts in aerospace field are used as test objects, and the reliability of the theoretical formula is further verified by tightening experiment. Finally, the influences of the material of bolt and nut, the material of joint, the thread specification, the structural form of nut and the number of tightening times on the torque coefficient and the repeated tightening performance of the wedge self-locking nut are studied systematically.