Bolt tightening method

Abstract

The invention provides a bolt tightening method. The bolt tightening method comprises the following steps: (1) establishing horizontal and vertical coordinates; (2) setting an initial torque value; (3) tightening the NOS angle value and calculating the average value Ta of the torque in the NOS angle value interval; tightening the INC angle value; tightening a second NOS angle value and calculating an average value Tb; (4) obtaining an angle starting value X1 and an angle value X2 corresponding to an end point of a theoretical linear stretching area angle, continuously rotating and tightening A-(X2-X1) from the end point of a second NOS angle value, and recording a final torque value at the same time; and (5) performing statistical distribution analysis on the final torque value based on the tightening data of preset test times, setting a final torque threshold range, judging that tightening is qualified when the actual final torque value falls into the threshold range, and judging that tightening is unqualified if the actual final torque value exceeds the threshold range. According to the method, the final pre-tightening force after the bolt is tightened can be accurately controlled, the influence of the friction coefficient of the bolt and the clamping piece on the final pre-tightening force in a traditional tightening method is eliminated to the maximum extent, and the pre-tightening force is better controlled.

Description

technical field [0001] The invention relates to screw connection technology, in particular to a bolt tightening method. Background technique [0002] The bolt axial force is the process of tightening the nut so that the bolt is screwed into the threaded hole according to the bolt thread, and the elastic force generated by the bolt in the elastic range is the bolt pre-tightening force. Since the pre-tightening force cannot be directly controlled and monitored, the pre-tightening force after the bolt is tightened is generally controlled indirectly by controlling the torque or controlling the angle in production. [0003] At present, the commonly used methods are pure torque control method and torque angle control method, and the bolt pretightening force controlled by torque angle is usually more accurate than the bolt pretightening force of pure torque control method, but the above two methods have partial tightening process Torque control is used, and the torque control pret...

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Problems solved by technology

[0003] At present, the commonly used methods are pure torque control method and torque angle control method, and the bolt pretightening force controlled by torque angle is usually more accurate than the bolt pretightening force of pure torque control method, but the above two methods have partial tightening process Torque control is used, and the torque control pretightening force will be greatly affected by the friction coefficient, but due to the limitation of the production process, the friction coefficient cannot be well controlled, which leads to the pretightening force after the bolts are tightened in actual production. large deviation

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