l 轻型货车动力转向系统结构设计
摘 要
汽车在行驶的过程中，需要按照驾驶员的意志经常改变其行驶方向，即所谓的汽车转向。汽车的转向系统是一套用来改变或恢复汽车行驶方向的专用机构，本文的研究内容是轻型货车动力转向系统结构设计。
本文针对的是与非独立悬架相匹配的整体式两轮转向机构。利用相关汽车设计和连杆机构运动学的知识，首先对汽车总体参数进行设计，在此基础上，对转向器，动力转向机构，转向传动机构进行选择，接着再对转向器，动力转向机构和转向传动机构（主要是转向梯形）进行设计，最后，利用软件AUTOCAD完成转向系统的设计图纸。
转向器在设计中选用的是循环球式齿条齿扇转向器，在对转向器的设计中，包括了螺杆—钢球—螺母传动副的设计和齿条—齿扇传动副的设计，前者是基于参照同类汽车，确定出钢球中心距，设计出一系列的尺寸，而后者则是根据汽车前轴的载荷来确定出齿扇模数，再由此设计出所有参数的。
动力转向机构的设计选用的是半整体式动力转向器，其分配阀装在转向器上。在对动力转向机构的设计中，包括了动力缸尺寸，分配阀参数，回位弹簧的设计计算。
转向梯形的设计选用的是整体式转向梯形，本文在设计中借鉴同类汽车转向梯形设计的经验尺寸对转向梯形进行尺寸初选。再通过对转向内轮实际达到的最大偏转角时与转向外轮理想最大偏转角度的差值的检验，和作为一个四杆机构对其最小传动角的检验，来判定转向梯形的设计是否符合基本要求。
本文在消化，吸收，总结，归纳前人的成果上，系统、全面地对转向系进行理论分析，设计及优化。为轻型货车转向系统的结构设计提供了一种步骤简单的设计方法。
关键词：转向系；转向器；动力转向；转向梯形
Van power steering system structure Designing
Abstract
In a moving vehicle, the driver will need to frequently change its traveling direction, the so-called steering. Vehicle steering system is used to change or restore a car in the direction of a dedicated agency, the contents of this paper is the study of design of Van power steering system structure designing.
This article is aimed at non-independent suspension and would like to match the overall style of the two steering. The use of the relevant vehicle design and kinematic linkage of knowledge, first of all, the overall parameters of the vehicle design, in this basis, the steering gear, power steering mechanism, steering transmission choice, and then to the steering gear and steering transmission (mainly trapezoidal steering) design, and finally, the use of AUTOCAD software and the steering gear steering linkage to complete the design drawings.
Steering the ball of choice is the cycle of fan-type steering gear rack teeth, in the design of steering gear, including a screw - Ball - Vice-nut drive the design and rack - fan drive gear pair design, the former is based on the reference to similar vehicles, to determine the center distance of the ball, the design of a series of size, while the latter is based on the vehicle front axle load to determine the fan module out of gear, and then all of the resulting design parameters.
Power steering mechanism design is half integral power steering gear, the distributing valve installed in steering gear. In the design of power steering mechanism, including power cylinder size, corundum, additional parameters and design calculation of spring.
Steering linkage design is a whole selection of steering, the paper design is used in car steering linkage from a similar experience in the design of the size of the steering linkage to the primary size. Through to the actual steering wheel in the maximum deflection angle with the steering wheel in the most ideal test of the difference of deflection angle, and four institutions, as a minimum transmission angle of its examination, to determine whether the design of steering trapezoid in line with the basic requirements.
In this paper, digestion, absorption, and summing up the results of their predecessors, the systematic, comprehensive steering system to carry out the oretical analysis, design and optimization. For the Van power steering system structure designing provides a simple design method steps.
KeyWords Steering system and Steering Gear，Power steering，Steering trapezium
目 录
摘 要 I
Abstract II
第 1 章 绪论 1
1.1 转向系概述 1
1.2汽车转向系统的现状及发展趋势 1
1.3 本课题主要研究内容 3
第 2 章 汽车总体参数的确定 5
2.1汽车形式的选择 5
2.2汽车主要参数的选择 6
2.2.1汽车主要尺寸的确定 6
2.2.2汽车质量参数的确定 7
2.2.3汽车性能参数的确定 9
2.3轮胎的选择 12
2.4本章小结 12
第 3 章 汽车转向系方案的选择 13
3.1 转向系主要性能参数 13
3.1.1转向器的效率 13
3.1.2传动比的变化特性 14
3.2 转向系的选择 18
3.3 液压助力转向机构布置方案分析 20
3.3.1动力转向机构布置方案 20
3.3.2动力转向器结构形式的选择 21
3.3.3分配阀的结构方案 21
3.4液压系统方案分析 22
3.4.1常用转向液压系统工作原理 22
3.4.2系统设计工作原理 22
3.5转向传动机构的选择 24
3.6转向梯形的选择 26
3.7本章小结 27
第 4 章 转向系的设计计算 28
4.1 转向器的结构型式选择及其设计计算 28
4.1.1 螺杆—钢球—螺母传动副的设计 28
4.1.2 齿条、齿扇传动副的设计 32
4.1.3 循环球式转向器零件强度计算 38
4.2 动力转向机构的计算 42
4.2.1 动力缸尺寸的计算 42
4.2.2 分配滑阀参数的选择 43
4.2.3 动力转向器的评价指标 47
4.3 转向传动机构设计 48
4.3.1 转向摇臂的计算 49
4.3.2 转向纵拉杆与横拉杆的计算 50
4.4整体式转向梯形结构优化设计 51
4.5转向系结构元件 57
4.6本章小结 59
结 论 60
致 谢 61
参考文献 62
