Preload Analysis And Improving Methods Of Bolt Connection In Automotive Aluminum Alloys Wheel

Bolt connection is the main connection way of automobile hub.Its preload design and control affect the safety and reliability of hub bolt connection.Anti-loosening ability of bolt connection and bolt fatigue strength can be enhanced by increasing bolt preload.Aluminum alloy wheels are generally used on automobile.For aluminum alloy is soft,hub bolt connection structure contact state is changed,bolt preload is insufficient,the bolt may loose and fracture,affecting automotive driving function and safety.In this paper,automobile aluminum alloy hub bolt preload is studied,the main contents are as follows:According to conical interference connection theory and elastic punch contact model,mechanical analysis model of the hub bolt cone connection in the tightening process is established.Calculating formulas of friction torque,bolt tension moment and bolt preload force are deduced.Conical interference fit geometry model is established to analyze the elastic-plastic state of hub conical hole and nut.By calculating the deformation of internal and external threads,the axial force distribution of coupling threads is obtained.Calculation algorithm of wheel hub bolt preload is established based on MATLAB,analyzing the influence of various factors such as thread angle,nut cone angle and nut cone friction coefficient on bolt preload.The mechanism affecting bolt preload is analyzed from the source.Bolt preload improving methods and measures are proposed.The mechanism of improvement of bolt preload and improvement measures are put forward.The finite element model of hub bolt connection is established through ABAQUS.Material model and contact model are determined.Mesh of each component is reasonably divided.Load and boundary conditions are set.The stress and strain distribution and the axial force distribution of coupling threads are obtained.Influencing factors of bolt preload are analyzed.Hub bolt connection experiment is used to collect the bolt strain value and analyze the test data.The variation rule of bolt preload is studied,The theoretical results,simulation results and experiment results are compared to verify the results accuracy of bolt preload.