基于3DCS的麦弗逊悬架前轮外倾角偏差分析

为验证零件制造及装配偏差是否满足麦弗逊悬架前轮外倾角偏差设计要求,基于三维偏差分析软件3DCS建立误差分析模型,对前轮外倾角偏差进行仿真分析,同时基于前轮外倾角计算公式,对其进行理论分析与计算。依据分析结果对影响最大的零件公差进行修正,将减振器与转向节装配偏差由0.7 mm改为0.3 mm,转向节与减振器安装孔位置度由0.6 mm改为0.4 mm,经计算及实际生产验证,前轮外倾角偏差满足设计要求,解决了麦弗逊悬架前轮外倾角过线率低的问题。     

模拟重力影响下的三维偏差分析模型创建研究

整车尺寸工程覆盖新车型开发的整个过程,这个过程中需要完成上百零件的公差设计。为缩短新产品的研发周期,并且制造出的新产品能够精确地达到设计的产品目标,高效准确的前期三维偏差分析与控制成为尺寸公差设计的重要环节。本文介绍了常用的三维偏差分析基本原理和偏差分析软件使用的假设条件,并且以公司某车型尾灯到尾门的装配为例,介绍了在考虑重力影响下的三维尺寸偏差分析模型的创建。本文采用软件提供的添加孔销Vis VSA浮动的自定义装配功能,模拟重力影响下前大灯和翼子板的装配,达到预期的研究目的。这种考虑重力因素影响下的三维偏差分析方法,可适用于汽车上其他零件的尺寸偏差分析。     

基于偏差分析的前照灯区域尺寸链优化

为了优化轿车前照灯区域尺寸链长及尺寸配合,更好地体现整车的设计水平和制造装配水平,文章介绍了三维偏差分析采用的蒙特卡罗模拟法算法及尺寸项目开发中的公差分配管理方法,实例分析了前照灯和发动机盖之间的装配偏差,优化了前照灯的定位方案.实践表明,借助偏差分析工具,对比研究零件定位方案,分析零件的偏差累积,以此来指导设计开发工作,可以提高设计稳健性,尤其在结构方案设计初期更具有指导意义.     

线性装配尺寸链计算程序设计及应用

采用计算机C语言全新设计了可独立运行、可同时计算封闭环的极值公差和统计公差的线性装配尺寸链计算程序,应用到发动机前端附件系统的相邻楔轮中心平面偏差的装配尺寸链计算过程中,通过设计相邻楔轮相关组成环的尺寸公差,使封闭环的最大统计尺寸对应的角度合理。多楔带通过了台架耐久试验和整车道路可靠性试验考核,未出现偏磨,验证了计算程序的实际效果。     

白车身开发过程中焊接精度控制

白车身的焊接精度决定整车的装配效果和性能,有效控制白车身的焊接精度,是车身质量的重要保障。白车身的主要偏差在于零部件各个环节公差的积累,控制车身偏差主要通过控制夹具、检具和模具的精度来控制公差的积累。如果车身匹配精度超过规定值,就会影响汽车制造质量、生产节拍和产品成本。保证白车身质量可以提高产品的市场竞争力。     

整车装配中线束失效模式分析

整车线束的正常运行是整车各项功能实现的前提。整车装配中频发的线束失效问题对整车制造效率及整车产品品质影响巨大。通过对整车装配过程中的线束失效模式进行系统分析,着重对线束失效模式进行了归类,并针对同类失效模式提出了相应的解决方案。文章可对线束设计以及整车装配过程中线束失效问题的解决提供帮助。     

白车身制造过程中对其Y向开度控制的研究

白车身Y向尺寸精度是保证整车总装内外饰DTS的基础,然而白车身的制造过程复杂,工艺烦琐,公差累计等诸多影响因子,导致整车的制造尺寸精度无法满足装配需求。通过现场多年造车经验及3DCS虚拟仿真,对产品结构、工装夹具、零件精度、焊接方式等一系列的控制,来保证白车身尺寸精度,满足整车装配。     

定性仿真在车身概念装配设计中的应用研究

简述了公差设计、定性仿真及定性建模等方面的研究现状,并探讨了定性仿真在车身概念装配设计阶段的工程应用、定性装配的可行性分析与车身装配的定性公差分析描述。仿真系统对装配特征的物理参数进行了定性信息提取,通过定性分析确定装配过程偏差的主要影响因素。     

基于VisVSA技术的汽车装配公差分析

VisVSA是一种以服从正态分布的蒙特卡罗法为计算核心,可以为机械系统装配提供高信度计算依据的公差分析软件。本文利用VisVSA技术对整车不同类型的集成分静态和动态两方面论述。在可能影响到装配性能的因素中,通过对比分析方式,重点论述了装配顺序对车门缝隙和面差的影响及装配公差在设计载荷下对底盘系统转向角度的影响。     

基于PCWR的薄板件装配偏差计算与控制研究

针对汽车车身设计中由于未考虑柔性薄板件装配误差而导致多次的试制和设计变更问题,提出了一种面向设计的装配偏差控制方法。该方法在设计阶段基于柔性薄板件焊接的定位、夹紧、焊接、释放(PCWR)过程进行焊接装配偏差分析,使用影响系数法和蒙特卡罗模拟法建立焊接装配偏差模型,并结合实例进行了偏差计算模型的验证。在装配偏差分析基础上使用遗传算法进行零件结构和公差的优化设计,从而以较低的成本实现对车身装配偏差的控制。     

车轮外倾角与前束值的设计匹配

车轮外倾角与车轮前束值是车轮定位中的两个重要参数,车轮前束是为了抵消车轮外倾产生的侧滑不利影响,因此前束值要与车轮的外倾角有合理的匹配。综合考虑车辆的结构参数和轮胎特性,基于车轮的侧滑机理,推导出车轮外倾角与前束值的合理匹配关系模型,用试验结果验证了模型的正确性,为在车辆的设计开发过程中,合理的确定车轮的外倾角与前束值提供理论参考。     

基于RBF神经网络的车轮定位参数识别

结合在侧滑试验台上做试验确定的车辆侧滑量与车轮外倾角及前束值间的映射关系，提出利用RBF神经网络对车轮定位参数优化识别的方法，并编制相应的程序。试验结果表明该方法能快速识别出车轮定位参数，并能指导检修人员进行车轮外倾角和车轮前束值调整。     

混合动力车型新增蓄电池Powerbox的车身更改开发设计探讨

主要论述了混合动力车型新增Powerbox在传统车型上装配时需要对白车身总成进行一定的更改设计,增加专用的Powerbox支架总成.设计方案在满足功能和性能的前提下,通过轻量化设计,适应满足传统制造工艺的生产模式,降低了制造成本.     

Kinematics of a smart variable caster mechanism for a vehicle steerable wheel

The lateral force of a tyre is a function of the sideslip and camber angles. The camber angle can provide a significant effect on the stability of a vehicle by increasing or adjusting the required lateral force to keep the vehicle on the road. To control the camber angle and hence, the lateral force of each tyre, we can use the caster angle of the wheel. We introduce a possible variable and controllable caster angle ? in order to adjust the camber angle when the sideslip angle cannot be changed. As long as the left and right wheels are steering together according to a kinematic condition, such as Ackerman, the sideslip angle of the inner wheel cannot be increased independently to alter the reduced lateral force because of weight transfer and reduction of the normal load F _z . A variable caster mechanism can adjust the caster angle of the wheels to achieve their top capacity and maximise the lateral force, when needed. Such a system would potentially increase the safety, stability, and maneuverability of the vehicles. Using the screw theory, this paper will examine the kinematics of a variable caster and present the required mathematical equation to calculate the camber angle as a function of suspension mechanism parameters and other relevant variables. Having a steered wheel about a tilted steering axis will change the position and orientation of the wheel with respect to the body of the car. This paper provides the required kinematics of such a suspension and extracts the equations in special practical situations. The analysis is for an ideal situation in which we substitute the tyre with its equivalent disc at the tyre plane.     

Dynamic analysis and control of an anti-lock brake system for a motorcycle with a camber angle

This paper analyses the dynamic response of a motorcycle with an anti-lock brake system (ABS) and camber or steering angle. Most studies have assumed that motorcycles brake in a straight line – that is, without a steering or camber angle. In this work, the performance of an ABS modulator is designed and analysed at first. Then, a controller is designed for motorcycle turning. The controller uses angular acceleration and the pressure value in brake calipers on the front and rear wheels, camber angle and lateral acceleration as commands to control brake pressure on each wheel to prevent wheel locking. The equation of motion for a motorcycle is based on Weir's equations. This motorcycle model combines a mathematical equation of the ABS modulator, tyre model and controller in simulations.     

客车发动机悬置软垫变形原因分析

本论文详细介绍了客车发动机悬置软垫的基本类型和安装要求。针对客车生产制造过程中常出现发动机悬置软垫变形的问题,从装配过程和设计原理上分析产生软垫变形的原因。     

南京长江三桥钢索塔施工测量技术

南京长江三桥为我国首座采用钢索塔结构的特大型斜拉桥。针对机加工车间的钢索塔节段预拼装工艺流程和桥位现场的钢索塔拼装施工流程,研究了预拼装过程中的微型控制网建立、测量点选择、钢索塔节段温度测量、钢索塔轴线偏差等方面的测量技术和数据处理方法。根据钢索塔的施工流程,提出了钢索塔拼装控制网布设、拼装定位等测量与数据处理方案;通过预拼装测量获取钢索塔已预拼装节段的状态,指导了钢索塔后继节段加工与调整,为桥位施工现场钢索塔拼装提供数据和保证了钢索塔拼装的顺利进行。南京三桥钢索塔的各项竣工数据指标均优于钢索塔验收标准,说明所采用的钢索塔施工测量方法完全满足特大型桥梁钢索塔设计、施工的需要,可以为同类型的工程提供参考。     

Two-Dimensional Contact Area of a Pneumatic Tire Subjected to a Lateral Force

A mathematical model of a two-dimensional contact patch of pneumatic tires rolling over a rigid flat road surface at arbitrary slip and camber angles has been developed. The model is simple in concept, contains few parameters and is applicable to any tire simulation models. In addition to tire geometric parameters and vertical deflection, the carcass camber angle is introduced in the model. This angle is alone responsible for the asymmetric shape of the tire contact patch when the tire undergoes a lateral force. The computed contact patches agree well with the measured patches of an automotive tire at different slip and camber angles. Lastly, the influence of the contact patch geometry on the tire cornering and aligning properties has been discussed through a computational example. It has been shown that the effect of tire contact patch geometry on the steady state behavior is rather remarkable.     

Computational model for analyzing the kinematics and compliance characteristics of a commercial vehicle’s front suspension system

This paper develops a computational model that can analyze the kinematics and compliance characteristics of the front suspension of a commercial vehicle. This computational model is called the flexible multi-body dynamic model because it is developed by interfacing the finite element model of the multi-leaf spring with the dynamic model of the front suspension. In this paper, the bump mode and roll mode tests are performed with a suspension parameter measuring device (SPMD). An excitation load for creating the bump mode and roll mode motion is applied on the left and right tires slowly in in-phase and out-of-phase modes. In the test, wheel rate, toe angle change, caster angle change, and camber angle change, which together represent the wheel alignment, are measured along with the longitudinal and lateral wheel center loci which together represent the wheel center trajectory change. The reliability of the developed computational model is verified by comparing the simulation results with the SPMD test results. The developed flexible multi-body computational model will provide useful information on kinematics and compliance characteristics in the earliest stages of the commercial vehicle design process.