In order to solve the problem that the cross-sectional parameters of AutoForm drawbead could not be directly used in 3D software design, this paper derived solution formula for the cross-sectional parameters of Z-direction drawbead that could be directly used in 3D software, mainly including the distance between the Z-direction elevation on the inflow and outflow sides and the centerline of the drawbead, convex fillets, and concave fillets. The drawbead designed using CATIA software was compared with the drawbead automatically generated by AutoForm, which yielded ideal validation results, with both the width and height errors controlled within the range of 0.05mm, and the draw-in error was controlled in 1 millimeter.

At present, most of the powertrains of medium and large luxury cars adopt the form of longitudinal engine rear-drive. Based on the assembly of a luxury brand vertical engine structure in the engine pre-assembly line of the assembly workshop, a specially designed engine carrier lifting fixture was used to realize the process installation of the parts. The lifting fixture was used to simultaneously lift the engine and transmission as well as the front axle assembly on the pre-assembly line, and automatically move the suspended integrated lifting fixture assembly and the workpiece on the pre-assembly line by carrying lifting fixture, thus completing the process installation of the parts. This paper discussed the application advantages and functional characteristics of this engine pre-assembly line process planning scheme and engine carrier lifting fixture for simultaneous suspension of multiple large mass parts, then introduced cases of lifting fixuture optimization.

To deal with the limitation of the existing non-destructive testing technology for the depth of the carburized layer of axle steel, a weak magnetic detection method is proposed. Since the stress concentrates at the junction of the carburized layer and its heart and can’t be eliminated, and then externally show a specific magnetic induction intensity for non. By collecting magnetic field signals from different samples of axle steel and different parts of axle steel, we analyzed the corresponding relationship between magnetic induction intensity amplitude and depth, and constructed a mathematical model for weak magnetic detection. The test results show that: spline outer circle (standard thickness/inspection thickness/absolute error): 3.50 mm/3.57 mm/0.07 mm; rod outer circle: 4.30 mm/4.46 mm/0.16 mm; R-angle: 4.00 mm/3.86 mm/-0.14 mm. The overall relative error of the inspection accuracy is less than 5%, which meets the actual needs of the factory inspection.

Since the line has to be stopped when replacing the electrode tip, the Overall Equipment Effectiveness (OEE) improvement of the automatic production line and manufacturing cost of per vehicle will be affected directly. To address this issue, this paper analyzed the electrode tip replacement time and frequency, used the linear programming model method to build a data replacement analysis model, summarized the risk level of replacement in different scenarios according to practical experience. At the same time, the standardized method of “fixed person, fixed time, fixed station” was implemented, and the final solution was determined after repeated iterative adjustment. After the grouping electrode tip replacement according to this strategy, the replacement frequency and time of electrode tip in the production line area has been reduced, and the overall OEE index has been significantly improved. At the same time, the cost of unit vehicle auxiliary materials was also optimized.

After the vehicle abuse road test, the eccentric bolt connecting spring swing arm and subframe rotates mainly because the flange surface of the bolt is convex, the friction on the flange surface is uneven, and the friction coefficient does not meet the standard requirements (standard value: 0.08~016, measured value: head friction coefficient is 0.25~0.27, and the total friction coefficient is 0.18~0.20). The friction surface of flange is line contact. Compared with the surface contact, this kind of bolt has poor anti-loose and anti-rotation performance. Improve the flatness of the bolt flange surface and the uniformity of the friction surface by the following measures: reducing the step height at the hexagon connection of bolts (from 3.2~3.25 mm to 3.1~3.15 mm), increasing the hole diameter of gasket before riveting (from 13.85~13.9 mm to 14.3~14.35 mm) and making the gasket into an opposite angle before riveting (0.5°~1°). The friction coefficient of optimized bolt is qualified, and there is no abnormal rotation failure after the vehicle abuse road test.

A Ls-dyna software based self-piercing riveting joint simulation method for vehicle crashworthiness analysis of was proposed in this research. Method of solving failure parameters for self-piercing riveting joint was studied based on the combination of finite element analysis and test in different forced states, thus improving simulation calculation efficiency while ensuring simulation accuracy. Firstly, a refined simulation model for riveted joints was established based on experimental design, afterwards, a simplified simulation model was established using *CONSTRAINED_SPR2. Using the extracted values from experimental and refined simulation results as simplified parameter inputs can greatly improve the calculation speed of the vehicle crash crashworthiness model. Through this study, it is shown that this method can achieve a simulation accuracy of over 90% for the peak failure force of the self-piercing riveting joint through calibration with experimental results, and can be applied to crashworthiness analysis of complete vehicle model.

Due to the fact that riveting technology is mostly applied for aluminum connection, its application in automotive Body In White (BIW) is limited. To solve the issue of compatibility between riveting process and other basic processes, this paper studied the integration of multiple riveting processes, designed a scheme to achieve multiple riveting processes emplying a single robot, validation analysis was conducted. The integration mainly includes self-piercing riveting process, rivetless self-piercing riveting process and rotary tapping riveting process. Meanwhile this paper also objectively analyzed the post-integration of other processes. The validation results indicate that the integration of multiple riveting processes can improve equipment start-up rate, reduce production costs and energy consumption in a single production cycle.

The fracture of a high-strength bolt used for fixing battery module of a new energy vehicle in the process of vibration test was investigated and analyzed through physical and chemical inspection, assembly process and vibration test. The results of investigation and analysis show that the cause of fracture is the formation of fatigue source caused by improper bolt assembly, the fatigue source continues to expand under the combined action of alternating stress and radial shear force at the upper and lower joint plane of the failed bolt along Z-direction vibration, which eventually leads to fracture.

In order to promote the development of flat wire motor technologies for new energy vehicles and introduce it into large-scale production, this article studied the paint removal welding process in the manufacturing process chain. A paint removal process plan for flat wire motors was developed. Based on the requirements of product characteristics and combined with the evaluation method of paint removal effects, the article analyzed the correlation between residual organic matter, surface roughness, heat affected zone length, welding pulling force, residual organic matter on the paint removal surface, and clearly defined the RFU value of paint quality within a limited range. By comparing the paint removal effects of different flat wire paint film insulation schemes, the article concludes that the laser paint removal process is adaptable to various insulation schemes, reducing the costs of model change. The article also analyzed comprehensively, guided practice and application of this process plan in aspects of paint removal effects, investment, application and maintenance.

To address the issue of automotive body weld seam sealant bubble, this paper started from the cause of automotive body sealant bubble, it firstly introduced 2 sealant bubble analysis methods including automotive body break-up analysis and section analysis, determined that excessive use of hemming sealant was the cause of sealant bubble, proposed the adjustment of slab gap and hemming sealant to eliminate sealant bubble. The results show that sealant bubble will be eliminated when slab gap is less than 0.02 mm, whereas adjustment of furnace temperature can only reduce the size of sealant bubble, can’t reduce the amount of sealant bubble.