In order to determine the assembly scheme of permanent magnet synchronous motor assembly for new energy vehicle, this paper compares the front magnetized rotor with rear magnetized rotor. The study shows that the magnetic flux of the front magnetization scheme is higher than that of the rear magnetization scheme, and its peak value external characteristics, comparison in the controlled variable motor test is less than 2%, which meets the requirements of power performance indicators, and the efficiency indicators of the two schemes are the same.Moreover, the rear magnetization scheme does not affect product performance, it is the best choice for the rotor assembly magnetization process for good assembly process, high yield, and low equipment maintenance cost.

To accumulate experience in the design and manufacturing of lightweight vehicle body connection technologies and enhance the quality of vehicle body mechanical connection processes, this paper summarizes and analyzes lightweight vehicle body mechanical connection technologies such as self-piercing riveting, rivetless connection, hot-melt self-tapping riveting, bolt connection, pull riveting and pressing riveting, and elaborates in detail the process principles, process characteristics, quality control methods and innovative process schemes of each process.

To increase the paint transfer efficiency, reduce production costs, minimize environmental pollution, and enhance production efficiency, this paper first introduces traditional automotive painting technology and the necessity of increasing the pain transfer efficiency, then elaborates the technical direction of paint atomization, and provides a detailed overview of several high paint transfer efficiency technologies, including electrostatic atomization, ultrasonic atomization, microporous atomization. It also elaborates fundamental principle, technical features and current development and application progress of these high print transfer technologies. After that, this paper compares the index and range of application of the above technical approaches as well.

In order to speed up the process of introducing aluminum engine hood, numerical simulation and Global Manufacturing Simulation (GMS) are used to verify the accessibility, interference, production cycle of the welding robot, and numerical simulation is used to confirm that the welding deformation can satisfy the process requirements, realize parallel engineering with production line, tooling and fixture, and accelerate the introduction of tooling and fixtures. Finally, the introduction cycle of models can be shortened by 3 months, cost reduction of 200,000 RMB, with improved welding quality.

In order to solve the issue of cracking in the polyvinyl chloride (PVC) fine sealing strips in the folded edge areas of passenger car doors, hoods, and trunk lids, and in conjunction with production manufacturing cases of PVC fine sealing strip cracking in the corresponding areas, the paper analyzes the cause of PVC cracking and proposes measures with metallographic analysis method. For the cracking caused by insufficient glue volume of folding edge glue, and sufficient inner and outer board bonding, measures are taken to increase the amount of glue, while ensuring the uniformity of the glue coating. For the cracking caused by external forces, measures are taken to optimize the PVC finishing process to avoid stress concentration. For the cracking caused by over-drying, measures are taken to control the drying time of the PVC. Through the above measures, the cracking are eliminated and solved.

In order to ensure the products applied Arplas welding process to meet users’ requirements, it is necessary to have a perfect and effective process quality standard, and a set of reasonable and effective control methods on the process and equipment to achieve the relevant process standards and quality standards. In this paper, the application of Arplas welding process at the D-pillar position of a vehicle model is taken as an example. Through the accumulation of practical application experience and process control optimization practice, the quality standard and inspection method of Arplas welding process are determined. At the same time, a set of process and equipment control methods are summarized through experience to meet the product quality standards applied in Arplas process.

Taking 22CrMo material passive bevel gear of drive axle as the research object, this paper studies the influence of material composition fluctuation on carburizing and quenching characteristics of bevel gear by finite element method. Based on the upper and lower limits of the fluctuation range of the material elements, two groups of material property databases are established using material database software. The heat treatment simulation software is used to establish a model to simulate the carburizing and quenching process of 2 groups of passive bevel gears, and the surface carbon concentration, microstructure evolution and gear deformation of bevel gears are compared and analyzed. The results show that the material composition fluctuation has great influence on the phase structure distribution and gear deformation of 22CrMo bevel gear after quenching, but has little influence on carburizing layer.

This paper analyzes the effects of Sr elements and different heat treatment states on the microstructure, eutectic silicon morphology, mechanical properties, and fracture mode of Al-Si-Mg alloy. The paper also proposes a way to improve the plasticity of Al Si Mg cast alloys by regulating the morphology of eutectic silicon and reducing the number and sizes of hard and brittle phases such as Al (Fe, Mn) Si. The results show that, after Sr modification, the straight sheet eutectic silicon is transformed into fine feather shaped eutectic silicon, the elongation of the aluminum alloy increases by 137% compared to unmodified, while the alloy strength doesn’t improve significantly. After heat treatment, eutectic silicon undergoes melting and spheroidization, changing the fracture mode and mechanical properties of the aluminum alloy. After artificial aging and solid solution treatment, the yield strength and the elongation of the aluminum alloy increase by 73% and 97% respectively compared to the cast state. The quenching temperatures have a significant impact on the mechanical properties of the 2# alloy by T6 treated. When the quenching temperature is 530 ℃, after artificial aging treatment, the tensile and yield strength of the aluminum alloy are increased by 14% and 100% respectively compared to the cast state, and the elongation remains unchanged, demonstrating superior comprehensive mechanical properties.

The shear-tensile properties of bonded joint, self-piercing riveted joint, bolted joint, self-piercing riveted-bonded joint, bolted-bonded joint of HC420/780DP steel and AA6063 extruded aluminum alloy are studied by shear tensile experiments. The results show that self-piercing riveting and bolting can damage the integrity of the plate, and stress concentration occurs in the contact position between the rivets or bolts with the plate during shear tensile process, leading to crack initiation and propagation, and eventually rivet pulling or tearing of AA6063 extrusion aluminum alloy. The structural adhesive increases the stress area of the steel/aluminum joint, and the AA6063 extrusion aluminum alloy with lower strength is broken during shear tensile process. The maximum shear load of bonded joint, self-piercing riveted-bonded joint, bolted-bonded joint are basically the same, but the energy absorption value of self-piercing riveted-bonded joint and bolted-bonded joint increases by 11.8% and 8% respectively compared to adhesive joint. When the steel/aluminum joint is in service under shear tensile load only, it may be considered to use structural adhesive alone for connection without the additional use of self-piercing rivet or bolt.

Considering the application trend of lightweight car body design and the demands for cost reduction, this paper selects metal, CFRP, PC/ABS, PC/PET, PC/PBT, PBT-GF30 as examples, and applies and studies the basic physical properties of sealants and the performance of adhesive strength, substrate matching, aging (thermal aging, damp heat aging, high and low temperature alternation, water resistance, low temperature resistance). The results show that the selected sealant can meet the design requirements except for the poor matching for some plastic substrates (PBT-GF30) at a low temperature of -40 °C. By introducing surface treatment methods such as grinding and plasma, the problem of poor matching of PBT-GF30 in -40 ℃ is solved. Therefore, this paper develops a sealant and process that can adapt to the use of multiple substrates, which can be used in the vehicle design and production.

In order to solve the extensive control of excessive large buffer area in and large welding workshop, large buffer stereoscopic storehouse during different shops transition, simple material flow control inventory quantity, Beijing Benz has developed an intelligent production flow management (PFM) system to assist the BIW to adopt the precise pearl chain order type production control mode, the application of the high flexibility new bin planning (0, X), (1,X) and (1+Y) further improves the workshop process equipment floor area and logistics area, reduces the workshop equipment investment, and reduces the body storage house volume.

Due to the significant difference in the position of the body pivot holes between the new model produced in an assembly workshop and the original one, the existing spreader can’t meet the production needs. Therefore, a solution is proposed to achieve co-production of 2 platform vehicle models by replacing the lifting fulcrum and rear support arm. This solution greatly reduces the modification workload of spreader and the impact on related equipment, shortens the spreader modification cycle, and reduces the cost in integrating new vehicle models. Based on the ANSYS simulation platform, the stiffness and strength analysis of the modified spreader under static and dynamic working conditions are carried out. Online no-load operation testing and vehicle assembly testing are carried out on the spreader samples. The results show that the modified spreader can meet the co-production needs of this dual platform models.