Analysis And Optimization Of Technological Parameters Of Support Bolts For Automotive Transmission

During the assembly process of the whole vehicle parts,the parts and the body are mainly connected by bolts.Bolt fastening is a commonly used bolting method.The quality of the bolt thread connection is related to the quality of the assembly of the car,and it will affect the driving safety during the driving process.The control of the fastening quality of the fastening bolts is mainly to control the pre-tightening force of the bolt connection.The bolt connection mainly consists of bolts,nuts and connecting parts.At present,various kinds of fastening wrenches and tightening equipment are widely used to fasten the connection between automobile bolts and connectors.In the second chapter,the fastening technology and tightening technology of transmission support and body connection bolt are analyzed.The assembly process of transmission support and body connection bolt and the significance of bolt torque control are introduced respectively.The process connection method of bolt connection,hard connection and soft connection are introduced.The comparison of different control methods,such as torque method,torque angle method,yield point method,elongation method and so on,is emphatically introduced.Chapter 3 introduces the main influencing factors of bolt quality of transmission support and body connection,including bolt pre-tightening force,torque coefficient,friction coefficient,material stiffness coefficient and so on.The relationship between pre-tightening force,dispersion of pre-tightening force and influencing factors,pre-tightening force and tightening torque are analyzed and studied respectively.This chapter also analyses the friction coefficient,which is the key factor affecting bolt tightening quality,and introduces the influence of thread friction coefficient,support surface friction coefficient and friction coefficient on the torque method.The fourth chapter is mainly about the analysis and optimization of the process parameters of the transmission support and body connection bolt,and introduces the method of determining the tightening method of the transmission support and body connection bolt,and introduces the electric tightening tool and the mass and energy index Cm and Cmk respectively.Use Ergospin hand-held electric tool to tighten.In this chapter,the torque method is used to test,the results of the test data are analyzed by Minitab software,the fastening process parameters are optimized,and the torque angle method is used to control,so as to realize the process optimization of transmission support and body connecting bolt.In the fifth chapter,the test data of different parameters are analyzed by using the method of torque and angle.At the same time,the required data are tested and analyzed twice.The results are verified by SPC statistical process control method and displayed by control chart.