电动汽车轮边减速系统的主动载荷谱设计原理研究

Electric vehicle (EV)with wheel hub driving is a competitive vehicle in future market.The ministry of science and technology of China lunched the important research program(973 program) on the basic science problems of distributional electric vehicle in 2011.As the kernel component of the EV,The wheel hub driving transmission, being a mass modal under suspension spring, needs to be light-weighted so as to ensure good driving stability.For it can't effectively reduce the weight of the transmission using the traditional design method,a new light-weighted design method of transmission will be explored in this program,which will focus on the principle of strength matching among major elements,such as spindles,gears and cases,of the transmission,each element with reasonable strength. The key points of the principle are designing the transmission's load spectrum corresponding to the standard road driving cycles based on the strength variable properties of elements materials,actively distributing the cycle numbers of strength strengthening and damaging to each element in the load spectrum,and as a result, realizing the full exertion of strength potential of each element in the transmission while the duration miles reached. This method changes traditional passively designing based on known load spectrum into actively designing load spectrum,so as to derive the duration goal of a system with minimum element strength.This method will supply a new way for the light-weight design of the transmission of electric vehicles and other conventional vehicles and improve the self-development capabilities.

分布式驱动电动汽车是未来极具市场竞争力的车型，我国科技部2011年启动了973项目对分布式驱动电动汽车整车基础问题开展研究。然而该车型的核心部件轮边减速系统作为簧下质量模块，直接影响整车操纵稳定性，轻量化问题亟待解决。传统设计方法在该部件轻量化方面难有作为，本项目重点探索在标准道路行驶循环工况下，减速系统主要元件间的设计强度匹配原理，使齿轮、轴、壳体等元件以适中的强度指标组成轻量化的减速系统。关键技术是基于不同元件材料的强度变化特性，设计出标准道路循环对减速系统产生的载荷谱，主动控制载荷谱中对各个元件的强度强化循环和损伤循环的数量，在耐久性里程达到时各元件的强度潜能都得到充分发挥。此技术将传统的被动依据载荷谱设计升级到主动设计载荷谱，达到以最佳的零件强度匹配实现系统耐久性指标的目的。不仅为电动汽车，也为传统车辆变速系统的强度匹配设计提供新的思路和方法，促进我国车辆自主开发水平提高。

轮边减速系统作为分布式驱动电动汽车簧下质量模块，直接影响整车操纵稳定性，轻量化问题亟待解决。本项目主要研究了在上海道路行驶循环工况下，减速系统主要元件间的设计强度匹配原理。通过四年的研究，提出了电动汽车标准道路循环下减速器零件载荷的转换方法，探索了基于整车标准道路循环工况的零件主动载荷谱设计原理，以耐久性里程指标为约束，设计了满足15万公里耐久性指标要求的电动汽车轻量化轮边减速系统，实现关联零件强度的合理匹配，主要零件中轴系减重32.88%，齿轮组减重40.55%，壳体减重27.09%；减速器共减重29.88%，形成了部件级动力传动系统轻量化设计方法,并通过10套轻量化减速器的台架耐久性试验验证了所提出的设计方法的有效性，为我国新能源汽车（包括传统汽车）的机械变速系统的轻量化开发提供了理论和方法基础，也为传统车辆变速系统的强度匹配设计提供新的思路和方法，推广应用此项成果，必将有力地促进我国车辆自主开发水平的提高。