汽车零部件(轴)的可靠性稳健优化设计

应用汽车零部件可靠性稳健优化设计的理论方法,对汽车典型轴系零部件,如半轴、前轴和后桥进行了可靠性稳健优化设计,给出了计算仿真分析结果,为工程实际的汽车零部件的可靠性稳健优化设计提供了理论依据。     

数控机床主轴激光热处理工艺研究

采用激光表面处理工艺,对数控机床主轴主要表面进行快速激光扫描,可获得高硬度的淬火硬化层.激光输出功率增大,淬硬层深度和宽度增加.     

Variable amplitude fatigue crack growth in a mild steel for railway axles: Experiments and predictive models

Railway axles, though designed for infinite life, are subject to failure due to various types of surface damage (ballast hits, corrosion) that might occur during their very long service life (30 years or 10⁷ km). This problem is dealt with by regular axle examinations in the form of nondestructive testing inspections, whose periodicity is calculated on the basis of the propagation lifetime of a given initial defect. The key point is therefore a reliable estimation of propagation lifetime under service loads.This paper discusses the application of predictive crack growth algorithms to the propagations of cracks in A1N steel axles. In particular, constant amplitude crack propagation tests on small-scale and “companion specimens” were carried out together with experiments on full-scale axles. Variable amplitude tests on companion specimens were performed and the results were then analysed using a simple “no-interaction” algorithm. Then, variable amplitude tests on companion specimens and the analysis of results with a simple “no-interaction” algorithm and the Strip-Yield model were dealt with.The results showed a negligible load-interaction effect on “companion specimens” and a significant retardation on full-scale axles. The consequences resulting from the application of predictive models to a full-scale axle under service spectrum were then analysed.     

铣床加工花键之方法改进

花键轴是电解天车上扭拔机构中的重要零件之一,起到提供扭矩和导向的作用。为使花键轴加工时保证精度的前提下提高效率,并能成批量的进行加工。通过对该机床的构造特点及工件外形的分析比对,对其在加工花键时的加工及装卡方法提出了改进,并制作了一套可以有效提高工作效率和保证产品质量的制具。     

Potential improvements of the presently applied in-service inspection of wheelset axles

Wheelset axles are safety relevant components because they are subject to high dynamic and static loads during operation. Therefore, they have to undergo periodic non-destructive examination to find potential defects before they can lead to failure. Minimizing the risk of fatigue failure for 3.5 million axles, potentially in service in Europe, was the objective of the 3.5 years R&D project EURAXLES which ended in April 2014. EURAXLES aimed to propose a global concept approach for axles design, production, and maintenance. An important objective within Work Package 5 was the analysis of the present status of in-service inspections. The strengths and weaknesses of the presently applied inspection systems and practices were evaluated with the aim to identify potential improvements provided by new technologies. That evaluation was firstly based on the results of a questionnaire which was distributed to the main European railway operators with the request to describe the testing procedures and equipment applied in their maintenance facilities. Secondly, the results of benchmark tests with presently applied ultrasonic inspection equipment were exploited for the analysis. These tests were performed at hollow axles and solid axles with implemented artificial defects.     

铁路车辆用LZ50钢车轴裂纹的形成机理

铁路车辆用车轴经锻造及机械加工后,在其表面常发现纵向裂纹,造成车轴报废。采用光学显微镜、扫描电子显微镜、能谱仪、维氏硬度计等分析手段,对LZ50钢车轴表面裂纹形成的机理进行了研究。发现车轴微裂纹的形成可有两种机理:一是车轴钢坯中的显微缩松在锻造时被轧扁但未完全弥合所致;二是由车轴钢坯中的氧化铝类夹杂物在锻造时形成裂纹源,导致车轴微观组织脆性穿晶断裂。     

细长轴切削的非线性系统动力稳定性分析

为了研究细长轴切削过程中的振动特征以及稳定性,运用轴承转子非线性分析理论研究非线性滚动轴承力和非线性切削力作用下的系统稳定性及失稳分叉规律.建立了非线性切削力模型和细长轴的有限元分析模型.通过周期解、Poincar(e)截面映射图确定系统的运动特性.经过计算,系统的失稳分叉方式是同步周期解经Hopf型伪周期分叉产生伪周期解.与空转情况相比,切削状态下的细长轴分又点转速下降近80%,且其分叉点转速范围较窄.在系统参数中,稳定性规律对转轴长径比和轴承刚度的变化比较敏感.通过双主轴驱动的细长轴切削实验可以得出,失稳前后系统的频率变化特征和运动形态与计算结果一致.为提高切削稳定性,失稳颤振的预测和监测提供理论依据.     

细长轴加工中刀具几何参数的选择

分析了细长轴加工的特点,介绍了细长轴加工中刀具几何参数的合理选择,并对其他工艺参考书中忽略的刀具前角和刃倾角对细长轴加工的背向力的影响作了介绍。     

铰接式车辆非驱动桥转向差速机构研究

基于ADAMS环境验证了铰接式车辆转向过程中内外侧轮胎转速不同时,车辆所产生的转弯半径的结果进行比较,分析除转向角及前后轮轴距外,影响车辆转弯半径的关键因素是内外侧轮胎速度差,并对非驱动桥结构转向差速进行深入研究和探讨,提供一种液压差速机构供实际生产需要参考。     

细长臂打磨机器人结构设计

针对细长圆筒形薄壁壳体设计了打磨机器人,对打磨机器人进行了结构设计,并利用有限元软件 ANSYS 对细长臂进行了优化,以此来保证打磨的精度和效率。试验结果显示,该机器人具有良好的稳定性,能实现高精度的打磨。