Research On Preload And Tightening Technology Of Bolt Connection In High-speed Rail

The wheels of the high-speed train are the important components for ensuring the running of the train.They consist of wheels and brake discs.Brake discs are bolted to the spokes and are the source of high-speed rail braking.The working conditions of the connecting bolts are very complicated,and it needs to withstand the centrifugal force caused by its own weight and high-speed rotation,as well as the impact caused by temperature and vibration.Once the bolt fails,the train brake will be abnormal,resulting in disastrous consequences.Bolt pre-tightening force requirements and fastening technology cannot be used universally,and each type of wheel needs specific solutions.High-speed rail adopts imported bolts and tightening technology at present.Newly-produced vehicles still need to develop fastening technology.This paper expounds the principle of high iron wheel bolt connection,by analyzing wheel assembly,bolt strength and the temperature impact and vibration load,explored the scope of the preload and develop tightening processes.We obtain the influence factors of the tightening torque from analysis of the bolt tightening process,and establish the relationship between the tightening torque and the pre-tightening force,and tightening data are combined to obtain the mathematical model available for the project.Analyzed the influence of the wheel and plate after tightening under the temperature change.In addition,the finite element model of the wheel and plate connector was established in this paper.The influence of temperature load on the pre-tightening force was obtained through the thermo-structure coupling analysis considering the transient temperature change while braking.Dynamic model was established based on the rail structure,and the harmonic response analysis and random vibration analysis were carried out based on the track surface roughness.A reasonable range of preload force is obtained when considering all,and the effects of friction coefficient and tightening method are analyzed,and the tightening process is formulated based on the relationship among preload,torque,and angle.