Effect of Pitch Difference on Stress Distribution of Thread Pair and Preload

doi:10.3901/JME.2021.17.132

Abstract

Abstract: The contact stress distribution law of the thread pair and the bearing surface in the bolt connection structure plays a key role in the assembly preload and connection reliability. The thread pitch difference generated during the threading process changes the contact stress under ideal conditions. The resulting change in thread engagement sequence will not only affect the stress distribution of the thread pair but also the stress distribution of the bearing surface, so that the relationship between the torque and the preload during the bolt tightening process will also change. Aiming at the above phenomenon, taking M10 bolt connection as an example, the theoretical model of screw thread engagement under the pitch difference is established, and the mechanism of stress redistribution is revealed. A fully parameterized three-dimensional finite element model of the bolt tightening process is established, and different The influence of the thread pitch difference distribution pattern on the thread pair stress, bearing surface stress and bolt assembly preload, and through the selection of internal and external thread pitches, the thread pair stress is evenly distributed. Finally, through the single bolt tightening experiment, the relationship between the pitch difference and the thread friction torque, bearing friction torque and bolt preload is established, and the accuracy of the simulation model and the above theory is verified.

Key words: pitch difference, thread pair, stress distribution, preload

CLC Number:

TH122

ZHANG Wei, LIU Yang, HOU Bowen, CHEN Dean, SUN Wei, HAN Xiao. Effect of Pitch Difference on Stress Distribution of Thread Pair and Preload[J]. Journal of Mechanical Engineering, 2021, 57(17): 132-148.

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