【作者】 毛建中；

【导师】 钟志华；

【作者基本信息】 湖南大学 ， 车辆工程， 2009， 博士

【摘要】 本论文设计与分析了一款基于菱形车的中悬架;由于菱形车具有碰撞安全性好,转弯半径小的优点,因此其具有较强的工程应用与科学研究价值;文中主要内容侧重于中悬架系统的设计与分析并通过整车试验来验证中悬架设计的可行性与合理性;由于菱形车驱动轮中置,为避免车厢中部凸起而影响车内的空间使用与布置,对减振元件与弹性元件分别采用了筒式减振器与扭力减振器、扭杆与板簧两种方案并对其进行比较,在性能得以提升的前提下降低悬架系统高度方向尺寸,满足菱形车的结构与布置需求。文中还对菱形车的侧倾和制动进行了研究和分析,得出了菱形车的制动策略。最后本文对菱形车进行了详细地现场试验,试验结果令人满意,达到了国家规定的试验标准。在导向元件的设计中,鉴于双横臂悬架具有高度尺寸小和操纵稳定性好的优点,本文采用了这一结构;采用传统的悬架导向元件设计方法获得基本参数,通过张量理论建立起动力学模型,借助ADAMS和Matlab软件,对其进行了结构的优化,从而精确地定出了各导向杆件的空间位置与相关尺寸,且以此建立起相应的三维数模。在弹性元件的设计与分析中,本文对扭杆的选用作了较详细的设计计算;对板簧的设计作了较充分的分析,特别是对板簧的刚度、长度、应力均分别采用了共同曲率法、集中载荷法和改良集中载荷法等不同的计算方案,并对其作了相应比较,尤其是对板簧横置时的刚度作了深入的分析与计算。通过对扭杆与板簧的比较,且基于菱形车结构与对悬架变刚度的需求,最后选用了板簧结构;因为弹性元件主要失效形式之一是疲劳,故本文对板簧进行了疲劳分析;由于汽车板簧所受载荷为非稳定变应力,文中引入疲劳损伤累积理论对菱形车的板簧进行了较为精细的疲劳计算。在减振元件的设计中,通过对车辆平顺性的分析,得出了菱形车中悬架所需要的阻尼特性曲线,为阻尼元件的计算提供了基础。通过对筒式减振器进行的设计与分析,确定了减振器的各种参数与数学模型。为减小高度尺寸采用了扭力减振器。利用扭力减振器提供的阻尼力矩与筒式减振器提供的阻尼力等价的思想,提出了筒式减振器与扭力减振器的换算关系,并以此确定扭力减振器的各个设计与选用参数及布置方案。制动和侧倾是车辆动力学研究的两个重点方向,本文对菱形车的侧倾工况和制动工况进行了较为详细地分析。借助Matlab/simulink软件对菱形车侧倾时发生的载荷转移和不同的制动形式进行仿真,并对其仿真结果进行了比较,得出了菱形车的制动策略,为菱形车制动系统的优化设计奠定了基础。本文对菱形车进行了较完整的整车试验,其试验内容为操纵稳定性六个和平顺性一个,共计七个试验,并对操纵稳定性试验进行了综合评价。通过试验与评价验证了菱形车具有与普通轿车相当的操纵稳定性与平顺性。这为菱形车未来的开发与研究奠定的充实的试验依据。论文中创造性地设计了一款采用双横臂做导向元件,板簧作弹性元件,扭力减振器作减振元件的悬架系统。根据设计计算与分析的结果,并通过试验,证实了菱形车的中悬架采用本论文的设计是完全可行的。本文还对菱形车的侧倾和制动问题进行了研究,得到了菱形车的制动策略。更多还原

【Abstract】 This dessertation makes the design and analysis on the middle suspension based on the rhombus vehicle. Since the rhombus vehicle has the advantage of good collision safety and small turning radius, there is strong engineering and scientific research value for it. This paper is mainly focus on the design in suspension system, and also carrying out the whole vehicle experiments to identify the feasibility and reasonableness of the design. As to the driving wheel middle layout, we took a variety of methods to decrease the vertical dimension of suspension system to avoid to decrease of useful space which was caused by the protruding of the middle part of the cab so that the structure and disposition of the rhombus vehicle can be most actualized. Investigation to roll and brake conditions of the rhombus vehicle, the dissertation also presents the brake methods of the rhombus vehicle. Finally, the rhombus vehicle was detailedly experimented in the dissertation. Experimental results was satisfied to reach to experimental standard established by countryIn the design of guiding components, considering that the double wishbone suspension system has the advantage of small vertical dimension, we chose it. Meanwhile, we also opimizated the structure through the genetic algorithm and the softwares of ADAMS and MATLAB and determined the space position of hardpoint and length dimension of each guiding components. At the same time, we constructed three-dimensional model of the guiding components.In the design and analysis of elastic components, a detailed calculation about the choice of torsion bars was made in the paper; a relatively thorough analysis about the design of the leaf spring was carried out, and a variety of calculation methods, such as common curvature method, concentrated load method and improved concentrated load method, are applied to the calculation of the stiffness, length, and stress of leaf spring, and a comparison between them is made, especially on the stiffness of leaf spring when it is installed transversally. The leaf spring structure is finally chosen to be the elastic elements of middle suspension based on the comparison between torsion bar and leaf spring as well as the requirements for variable stiffness of the suspension and the structure of the rhombus vehicle. Because the main reason for failure of elastic components is fatigue, a discussion on fatigue of the leaf spring is made. Also, since unstable variable stress is endured by the leaf spring, a precise fatigue calculation on the leaf spring of rhombus is made using the Fatigue Accumulation Damage theory.Design to damp elements, according to analysis of the vehicle ride, the damp characteristic curve of the middle suspension rhombus vehicle in order to provide bassis for calculating damp elements. Through analysis and design for the tube shock absorber, the all kinds of parameters and mathematical model were determined. In order to descrease vertical size, the torsion shock absorber was applied to middle suspension. Using the idea of the damp moment of the torsion shock absorber to be equal to the damp force of the tube shock absorber, the equivalent relations of the tube shock absorber and torsion shock absorber was presented. The design parameters and layout methods of the torsion shock absorber were determined.The brake and roll conditions are mainly investigated in vehicle dynamics. The dissertation detailed analyzed the roll and brake conditions of the rhombus vehicle. The load transfer of the roll condition and brake methods of the rhombus vehicle were simulated with Matlab/simulink software. The simulation result were compared and analyzed to obtain the brake methods of the rhombus vehicle. The brake methods establish basis for optimizing design brake system of the rhombus vehicle.We took series of experiments on rhombus-vehicles. The 7 experiments focused on the handling and ride characteristics of rhombus vehicles. Through these experiments, we proved that rhombus vehicles have the similar performance in the handling stability and ride with the ordinary layout cars.This paper originally presented a kind of suspension system which consisted of the double wishbone suspension as guiding components, leaf spring as elastic component and torsion shock absorber as damp components. According to comparison the simulation analysis and the experiments results, we proved that the design of this paper to the middle-set suspension of rhombus vehicle is feasible. Finally, the dissertation firstly analyzed the roll and brake conditions of the rhombus vehicle and present brake methods of the rhombus vehicle更多还原