1. The drive axle lightweight demand
The total mass of non-breaking drive axle and wheel, brake and brake drum accounts for about 11% to 16% of the chassis mass of ordinary trucks, and about 3.5% to 5% of the total mass of vehicles for heavy goods vehicles, its proportion is larger.
The lightweight drive axle not only reduces the unsprung mass, reduces the running noise, improves the vehicle comfort and passability, but also reduces the material use and its own power consumption.
2. The main methods of low-cost lightweight technology
Automotive lightweight needs to consider five factors: performance, function, process, cost and weight.
Low cost lightweight requires the minimum cost, weight and process investment in exchange for the best safety, NVH, durability and other performance, and to achieve the corresponding system functions.
3. Drive axle development status
The drive axle is the mechanism at the end of the drive line that changes the speed and torque from the transmission and transmits them to the drive wheels.
The drive axle is generally composed of the main reducer, the differential, the half shaft and the drive axle housing. In addition, the drive axle also has to withstand the vertical force between the road and the frame or body, the longitudinal force and the lateral force, as well as the braking torque and reaction force. With the continuous progress of automotive technology, the drive axle reflects the application of lightweight technology to different degrees.
4. New material application of drive axle
At present, the use of lightweight materials is one of the most important ways to achieve lightweight goals. The use of materials to achieve lightweight is mainly divided into two cases, one is the use of low-density materials, such as aluminum alloy, magnesium alloy, alloy, plastic or a variety of composite materials; The other is to use high-strength materials, so as to reduce the amount of material, reduce the weight such as the use of high-strength steel and so on. Weight loss effect: Taking aluminum alloy as an example, the density is only 1/3 of the density of iron, based on structural optimization analysis, its weight loss effect can reach 40%-60%.
5. New technology application of drive axle
In the product design and development, under the premise of ensuring the product structure and performance requirements, try to use new technologies or processes to integrate and hollow the structure and parts, so as to reduce the weight of the product and achieve the goal of lightweight. At present, the most widely used forming technology mainly includes laser welding, internal high pressure forming technology, hot pressing forming, hydraulic forming, powder metallurgy and other technologies.
Drive axle housing: The domestic drive axle housing mostly uses the traditional casting axle housing and stamping welding axle housing. The high pressure forming in the drive axle housing is a new process, with high material utilization, energy saving, material saving, consumption reduction, fewer processing procedures, high processing efficiency, easy to realize mechanization, automation, reasonable wall thickness distribution of parts, high strength, stiffness, light weight and other advantages.
6. Application of structure optimization technology
Through finite element analysis technology, based on vehicle performance indicators such as mass, fatigue life, stiffness and modal frequency, the drive axle lightweight collaborative optimization design process is established. Sensitivity analysis, topology optimization, size optimization, morphology optimization, multi-objective genetic method and other optimization methods are adopted, combined with lightweight materials and advanced technology applications, under the condition of achieving manufacturing feasibility and weight reduction standards. The performance meets the development target requirements.
7. Drive axle lightweight technology development trend
Lightweight technology innovation strategy: Establish a cooperation mechanism between production, learning, research and application, from the development and promotion of materials to parts, give full play to their respective advantages such as high efficiency, enterprises and research institutes, accelerate the transformation of scientific research results, and effectively promote the development and application of lightweight technology innovation products.
Drive axle parts integration, hollowing, lightweight, composite, localization is a hot spot in order to reduce costs, based on the integration of structural optimization technology and hollowing, based on the application of new materials, based on performance and cost consideration of composite, domestic replacement of imported materials is a hot spot of technology development.
Drive axle optimization technology application can minimize costs: through the integrated design of the drive axle components, fully consider the functions of multiple parts, combined with CAE analysis technology optimization, can shorten the development cycle, reduce research and development costs, and improve the market competitiveness of the product.
Lightweight evaluation and reasonable control of cost: the lightweight design and application of the drive axle need to cover the target set of the production process and maintain the balance between materials, processes and costs, and find the preferred target set in order to finally achieve the established lightweight design goals, which has become the future direction and development trend of the lightweight application of the drive axle.