A method of tightening bolts

Abstract

The invention provides a bolt tightening method, comprising (1) establishing the horizontal and vertical coordinates; (2) setting the initial torque value; (3) tightening the NOS angle value and calculating the average value Ta of the torque in the NOS angle value interval; Tighten the INC angle value; Tighten the second NOS angle value and calculate the average value Tb; (4) Get the initial value of the theoretical linear stretch zone angle X 1 The angle value corresponding to the end point is X 2 , continue to rotate and tighten A‑(X 2 -X 1 ), and record the final torque value at the same time; (5) Based on the tightening data of the predetermined number of tests, perform statistical distribution analysis on the final torque value, set the final torque threshold range, and determine that the tightening is qualified when the actual final torque value falls within the threshold range, if If it exceeds the threshold range, it is judged that the tightening is unqualified. The present invention can accurately control the final pre-tightening force after the bolts are tightened, eliminate the influence of the friction coefficient of the bolts and clamping parts on the final pre-tightening force to the greatest extent in the traditional tightening method, and better realize the control of the pre-tightening force.

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...

AI Technical Summary

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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