人人文库网 > 图纸下载 > 毕业设计 > 齿轮齿条式转向器设计【优秀机械毕业设计】【word+7张CAD图纸全套】

齿轮齿条式转向器设计.doc

齿轮齿条式转向器设计【优秀机械毕业设计】【word+7张CAD图纸全套】

资源目录

[A0032]齿轮齿条式转向器设计【优秀机械毕业设计】【word+7张CAD图纸全套】.zip

齿轮齿条式转向器设计.doc---(点击预览)

诚信承诺书.doc---(点击预览)

毕业设计（论文）开题报告.doc---(点击预览)

毕业设计（论文）任务书.doc---(点击预览)

曹佳珺中期检查表.doc---(点击预览)

A3齿轮轴.dwg---(点击预览)

A2齿条衬套套管.dwg---(点击预览)

外文翻译

外文翻译=汽车转向系统=3200字符.doc---(点击预览)

文献综述

文献综述封皮.doc---(点击预览)

文献综述.doc---(点击预览)

齿轮齿条式转向器设计_检测报告

PDF报告.pdf---(点击预览)

css

printstyle.css

report_detail.css

report_xiangxi.css

images

topline.gif---(点击预览)

topbg_black.gif---(点击预览)

topbg.gif---(点击预览)

stamp_print.gif---(点击预览)

stamp.gif---(点击预览)

print_xspd.gif---(点击预览)

print_pdlb.gif---(点击预览)

print_jghz.gif---(点击预览)

print_jcjl.gif---(点击预览)

pdf_xiangxi.jpg---(点击预览)

nochecked.gif---(点击预览)

menu_submit.gif---(点击预览)

menu_report.gif---(点击预览)

menu_mzsm.gif---(点击预览)

menu_down.gif---(点击预览)

menu_detail.gif---(点击预览)

menu_back.gif---(点击预览)

lunwen_15.jpg---(点击预览)

logo_xiangxi.gif---(点击预览)

logo_jianjie.gif---(点击预览)

logo_black.gif---(点击预览)

logo_bidui.gif---(点击预览)

leftlinebg.gif---(点击预览)

leftbg.gif---(点击预览)

lc1_07.jpg---(点击预览)

icon_user.gif---(点击预览)

icon_unlog.gif---(点击预览)

icon_top.gif---(点击预览)

icon_search.gif---(点击预览)

icon_save.png---(点击预览)

icon_right.gif---(点击预览)

icon_print.png---(点击预览)

icon_message.gif---(点击预览)

icon_mail.png---(点击预览)

icon_faq.gif---(点击预览)

icon_ding.gif---(点击预览)

icon_computer.gif---(点击预览)

icon_attention.gif---(点击预览)

icon_arrow_red.gif---(点击预览)

icon_arrow_gray.gif---(点击预览)

icon_arrow_blue.gif---(点击预览)

icon_arrow01.gif---(点击预览)

example.gif---(点击预览)

dian_03.jpg---(点击预览)

d1.png---(点击预览)

color_yellow.gif---(点击预览)

color_red.gif---(点击预览)

color_green.gif---(点击预览)

color_black.gif---(点击预览)

close.gif---(点击预览)

checked.gif---(点击预览)

script

highcharts.js

jquery-1.7.1.min.js

reportall.js

reportshow.js

比对报告.html

简洁报告.html

详细报告.html

压缩包内文档预览：(预览前20页/共25页)

编号：445076 类型：共享资源大小：995.28KB 格式：ZIP 上传时间：2015-06-30 上传人：小*** IP属地：福建

50
积分

版权申诉 word格式文档无特别注明外均可编辑修改；预览文档经过压缩，下载后原文更清晰！ 立即下载

关键词：: a0032 齿轮齿条转向器设计优秀优良机械毕业设计 word cad 图纸全套

资源描述：

您若下载本次文件，将获得（CAD图纸+word文档）源文件哦！

以下为本次文件的目录及部分图纸截图

【需要其他机械类资料可以联系QQ97666224】

!【详情如下】CAD图纸+设计说明书.doc[8000字，24页]【需要咨询购买全套设计请加QQ97666224】.bat

外文翻译

文献综述

曹佳珺中期检查表.doc

毕业设计（论文）任务书.doc

毕业设计（论文）开题报告.doc

诚信承诺书.doc

齿轮齿条式转向器设计.doc

齿轮齿条式转向器设计_检测报告

A0装配图.dwg

A1万向传动节.dwg

A1转向蜗杆箱.dwg

A1转向齿条.dwg

A2转向拉杆.dwg

A2齿条衬套套管.dwg

A3齿轮轴.dwg

摘要

当今我们社会的汽车发展水平很快，然而汽车的转向器则是汽车中一个重要的组成部分，它也影响着汽车操纵的稳定性，所以转向器的质量就很关键，如果质量不过关，那么会影响汽车的主动安全。

这次设计的是铃木北斗星的转向器，在齿轮齿条转向器的结构上是选用的侧面输入、两端输出，主要的优点就是结构比较简单。壳体主要是由铝或镁合金压铸成的，所以质量轻，在传动效率上可达百分之九十。齿轮齿条在长时间的工作后如果出现了磨损间隙，那么可以利用靠近在齿条背面与小齿轮的压紧力可调弹簧自动的来消除间隙，此转向器无转向摇臂，也没有直拉杆，同时能扩大转向轮的转角。齿轮齿条转向器的工作原理：转动方向盘时，在连接处有万向节并且通过它的旋转驱动齿轮轴，齿条和齿轮轴啮合，从而使齿条做线性运动，最终实现转向。

关键词：转向器；设计；发展；齿轮齿条

ABSTRACT

The level of vehicle development today in our society very quickly, but the car's steering is an important car part, it also affects vehicle handling and stability, so the quality of steering is very critical, if quality tests, then will affect the active safety of the car.

This design is the Suzuki Big Dipper steering, rack and pinion steering gear on the structure of the input side is chosen, both ends of the output, the main advantage is that the structure is relatively simple. The main case is made of aluminum or magnesium alloy die casting, so the quality of light in the transmission efficiency of up to 90 percent. Rack and pinion after long hours of work if there is a gap of wear, you can use the back of the rack near the clamping force and pinion adjustable spring automatically to eliminate the gap, this steering without steering arm, nor straight rod, while the steering wheel angle expand. Rack and pinion steering works: when turning the steering wheel, there is a universal joint at the junction and by its rotary drive gear shaft, rack and pinion shaft is engaged, so that linear motion of the rack, and ultimately turn.

Keywords: steering; design; develop; rack and pinion

1前言1

1.1选题的目的与意义1

1.2转向器的国内外研究现状1

1.3转向器的发展趋势1

2齿轮齿条转向器设计内容与方案2

2.1设计的主要内容2

2.2制定转向器设计的方案2

2.2.1转向器的输入与输出形式2

2.2.2齿轮齿条的选择3

2.2.3齿条断面形状的选择3

2.2.4齿轮齿条转向器布置形式3

2.3齿轮齿条转向器最终方案及结论4

3齿轮齿条式转向器的设计和计算4

3.1计算汽车的原地转向阻力矩4

3.2转向器角传动比的计算4

3.2.1转向轮侧偏角计算5

3.2.2角传动比的计算5

3.3作用在转向盘上的手力的计算5

3.4梯形臂长度计算（L2）6

3.5轮胎直径RT的计算6

3.6齿轮齿条式转向器的设计计算6

3.6.1齿轮齿条式转向器的设计要求6

3.6.2齿轮齿条转向器的主要部件7

3.7齿轮齿条式转向器的材料选择及强度校核8

3.8齿轮齿条的基本参数10

4齿轮轴的结构设计11

4.1齿轮齿条式转向器的受力分析与计算11

4.2齿轮轴的设计计算11

4.3齿轮轴的强度校核13

5转向器间隙调整弹簧的设计计算13

5.1选择材料并确定许用应力13

5.2根据强度条件计算弹簧钢丝直径13

5.3计算弹簧圈数和弹簧的自由高度14

5.4稳定性验算14

5.5检查δ及δ114

5.6几何参数和结构尺寸的确定14

5.7弹簧工作图15

6轴承、润滑方式和密封类型的选择15

6.1轴承的选择15

6.2润滑方式的确定16

6.3密封结构的确定16

7结论17

参考文献18

致谢19

A0装配图.jpg

A1万向传动节.jpg

A1转向齿条.jpg

A1转向蜗杆箱.jpg

A2齿条衬套套管.jpg

A2转向拉杆.jpg

A3齿轮轴.jpg

QQ截图20150627153407.jpg

QQ截图20150627154344.jpg

内容简介：: 汽车转向系统随着汽车电子技术的迅猛发展，人们对汽车转向操纵性能的要求也日益提高。汽车转向系统已从传统机械转向、液压助力转向(HydraulicPowerSteering,简称HPS)、电控液压助力转向(ElectricHydraulicPowerSteering,简称EHPS)，发展到电动助力转向系统(ElectricPowerSteering,简称EPS)，最终还将过渡到线控转向系统(SteerByWire，简称SBW)。机械转向系统是指以驾驶员的体力作为转向能源，其中所有传力件都是机械的，汽车的转向运动是由驾驶员操纵方向盘，通过转向器和一系列的杆件传递到转向车轮而实现的。机械转向系由转向操纵机构、转向器和转向传动机械3大部分组成。通常根据机械式转向器形式可以分为:齿轮齿条式、循环球式、蜗杆滚轮式、蜗杆指销式。应用最广的两种是齿轮齿条式和循环球式(用于需要较大的转向力时)。在循环球式转向器中，输入转向圈与输出的转向摇臂摆角是成正比的;在齿轮齿条式转向器中，输入转向圈数与输出的齿条位移是成正比的。循环球式转向器由于是滚动摩擦形式，因而正传动效率很高，操作方便且使用寿命长，而且承载能力强，故广泛应用于载货汽车上。齿轮齿条式转向器与循环球式相比，最大特点是刚性大，结构紧凑重量轻，且成本低。由于这种方式容易由车轮将反作用力传至转向盘，所以具有对路面状态反应灵敏的优点，但同时也容易产生打手和摆振等现象，且其承载效率相对较弱，故主要应用于小汽车及轻型货车上，目前大部分低端轿车采用的就是齿轮齿条式机械转向系统。随着车辆载重的增加以及人们对车辆操纵性能要求的提高，简单的机械式转向系统已经无法满足需要，动力转向系统应运而生，它能在驾驶员转动方向盘的同时提供助力，动力转向系统分为液压转向系统和电动转向系统2种。其中液压转向系统是目前使用最为广泛的转向系统。液压转向系统在机械系统的基础上增加了液压系统，包括液压泵、V形带轮、油管、供油装置、助力装置和控制阀。它借助于汽车发动机的动力驱动液压泵、空气压缩机和发电机等，以液力、气力或电力增大驾驶员操纵前轮转向的力量，使驾驶员可以轻便灵活地操纵汽车转向，减轻了劳动强度，提高了行驶安全性。液压助力转向系统从发明到现在已经有了大约半个世纪的历史，可以说是一种较为完善的系统，由于其工作可靠、技术成熟至今仍被广泛应用。它由液压泵作为动力源，经油管道控制阀向动力液压缸供油，通过活塞杆带动转向机构动作，可通过改变缸径及油压的大小来改变助力的大小，由此达到转向助力的作用。传统液压式动力转向系统一般按液流的形式可以分为:常流式和常压式2种类型，也可根据控制阀形式分为转阀式和滑阀式。随着液压动力转向系统在汽车上的日益普及，人们对操作时的轻便性和路感的要求也日益提高，然而液压动力转向系统却存在许多的缺点：由于其本身的结构决定了其无法保证车辆在任何工况下转动转向盘时，都有较理想的操纵稳定性，即无法同时保证低速时的转向轻便性和高速时的操纵稳定性；汽车的转向特性受驾驶员驾驶技术的影响严重；转向传动比固定，使汽车转向响应特性随车速、侧向加速度等变化而变化，驾驶员必须提前针对汽车转向特性幅值和相位的变化进行一定的操作补偿，从而控制汽车按其意愿行驶。这样增加了驾驶员的操纵负担，也使汽车转向行驶中存在不安全隐患;而此后出现了电控液压助力系统，它在传统的液压动力转向系统的基础上增加速度传感器，使汽车能够随着车速的变化自动调节操纵力的大小，在一定程度上缓和了传统的液压转向系统存在的问题。目前我国生产的商用车和轿车上采用的大多是电控液压助力转向系统，它是比较成熟和应用广泛的转向系统。尽管电控液压助力装置从一定程度上缓解了传统的液压转向中轻便性和路感之间的矛盾，然而它还是没有从根本上解决HPS系统存在的不足，随着汽车微电子技术的发展，汽车燃油节能的要求以及全球性倡导环保，其在布置、安装、密封性、操纵灵敏度、能量消耗、磨损与噪声等方面的不足已越来越明显，转向系统向着电动助力转向系统发展。电动助力转向系统是现在汽车转向系统的发展方向，其工作原理是:EPS系统的ECU对来自转向盘转矩传感器和车速传感器的信号进行分析处理后，控制电机产生适当的助力转矩，协助驾驶员完成转向操作。近几年来，随着电子技术的发展，大幅度降低EPS的成本已成为可能，日本的大发汽车公司、三菱汽车公司、本田汽车公司、美国的Delphi汽车系统公司、TRW公司及德国的ZF公司都相继研制出EPS。Mercedes2Benz和SiemensAutomotive两大公司共同投资6500万英镑用于开发EPS，目标是到2002年装车，年产300万套，成为全球EPS制造商。到目前为止，EPS系统在轻微型轿车、厢式车上得到广泛的应用，并且每年以300万台的速度发展。转向是一个专业术语，适用于采集部件，联系等，其中允许一艘(舰船)或汽车(轿车)按照预期的方向行驶.一个例外的情况是铁路运输由路轨组合在一起铁路道岔提供转向功能。许多现代轿车使用齿轮齿条式转向器，在方向盘末端有转动齿轮;该齿轮带动齿条移动，它是一种线性的齿轮紧密配合，从一边到一边。这种运动把转矩通过转向横拉杆和一种叫做转向节臂的短形臂传递给转向轮的主销。以前的设计往往采用循环球式转向器，而这种转向器仍然应用在卡车和多用途车辆。这是一种老式的螺母和齿扇设计，该转向管柱转动大螺丝(蜗轮)，它与一个齿扇齿轮啮合，当蜗轮转动时，齿扇也随之转动，一个安装在齿扇轴上且与转向联动有关的摇臂带动转向节臂，从而使车轮转动.循环球式转向器通过安装滚珠减少螺母和螺杆之间的摩擦;两根导管和螺母内的螺旋管状通道组合成两条各自独立的封闭的钢球“流到”。齿轮齿条式转向器设计具有很大程度的反馈和直接转向路感;它也通常不会有任何反弹，或呆滞。缺点是，它是不可调的，因此当它磨损唯一的解决办法更换。循环球式转向器的优点是机械优势，因此，它被使用在较大较重的车辆，而齿轮齿条式原本仅限于较小和较轻;由于几乎普遍采用动力转向系统，不过，这已不再是一个重要的优势，导致越来越多地在新型汽车应用齿轮齿条式转向器。循环球式转向器设计在中心也有明显的冲击，或死点。凡一分钟交替方向盘出不来并不移动转向机构;这是很容易可调螺杆的端部来减少磨损，但它并不能完全消除或机制开始磨损很快。这项设计目前仍在使用中，在卡车和其他大型车辆，也应用于迅速转向，路感与稳健性，可维护性，和机械的优势相比不太重要的场合。较小程度的反馈，这样的设计也有时是一种优点;当前轮碰撞时，使用齿轮齿条转向的司机只有自己的大拇指受伤，造成方向盘揭开一边突然(因为驾驶教练告诉学生把自己的大拇指在前面的方向盘，而非放在左右的内边缘).这种效果在像卡车一样的重型汽车更为明显;循环球式转向防止这种程度的反馈，只是因为它可以在正常情况下防止可取反馈。转向连锁连接转向器和车轮通常符合一个阿克曼转向几何的变化，它交代了一个事实:当转向是，内轮转过的半径比外轮小得多，因此适合驾驶的直路，是不适合曲折。由于车辆已成为较重而改用前轮驱动，为了扭转方向盘，通常的，主要的是体力。为了解决这一问题，汽车业发展的动力转向系统。有两种类型的助力转向系统-液压和电气/电子。还有一种液压-电动混合系统。液压助力转向系统(hps)利用油压供应的一个发动机驱动泵，以协助将方向盘转转动。电动助力转向系统(EPS)方式，是较有效率的液压助力转向系统，由于电动助力转向汽车只需要提供协助时，方向盘被转动，而液压泵必须不断运行。在EPS的帮助下是很容易调节车型，最高车速，甚至驾驶的喜好。另外一个好处是，通过泄漏和处置动力转向液消除对环境构成危险。动力转向的分支是速度可调转向而转向是大量辅助以低速行驶，稍微协助高速。汽车制造商认位，当要停车时驾驶人可能需要做出大量转向投入，但当时高速行驶时则不然。第一辆有这特点的汽车，是雪铁龙与其diravi，虽然改变了现代汽车转向系统资金的投入，但它改变了定心凸轮的压力，使得方向盘尽力去回到原来的位置。现代速度可调式动力转向系统，当速度增长时减少了活塞的压力，给予更直接的感受，这一特点在所有新车正逐渐成为司空见惯。 Themotorturningsystem Along with automobile electronic technology swift and violent development, the people also day by day enhance to the motor turning handling quality request. The motor turning system changed, the hydraulic pressure boost from the traditional machinery changes (Hydraulic Power Steering, is called HPS), the electrically controlled hydraulic pressure boost changes (Electric Hydraulic Power Steering, is called EHPS), develops the electrically operated boost steering system (Electric Power Steering, is called EPS), finally also will transit to the line controls the steering system (Steer By Wire, will be called SBW).The machinery steering system is refers by pilots physical strength achievement changes the energy, in which all power transmission all is mechanical, the automobile changes the movement is operates the steering wheel by the pilot, transmits through the diverter and a series of members changes the wheel to realize. The mechanical steering system by changes the control mechanism, the diverter and major part changes the gearing 3 to be composed.Usually may divide into according to the mechanical diverter form: The gear rack type, follows round the world -like, the worm bearing adjuster hoop type, the worm bearing adjuster refers sells the type. Is the gear rack type and follows using the broadest two kinds round the world -like (uses in needing time big steering force).In follows round the world -like in the diverter, the input changes the circle and the output steering arm pivot angle is proportional; In the gear rack type diverter, the input changes the turn and the output rack displacement is proportional. Follows round the world -like the diverter because is the rolling friction form, thus the transmission efficiency is very high, the ease of operation also the service life are long, moreover bearing capacity, therefore widely applies on the truck. The gear rack type diverter with follows round the world -like compares, the most major characteristic is the rigidity is big, the structure compact weight is light, also the cost is low. Because this way passes on easily by the wheel the reacting force to the steering wheel, therefore has to the pavement behavior response keen merit, but simultaneously also easy to have phenomena and so on goon and oscillation, also its load bearing efficiency relative weak, therefore mainly applies on the compact car and the pickup truck, at present the majority of low end passenger vehicle uses is the gear rack type machinery steering system. Along with the vehicles carrying capacity increase as well as the people to the vehicles handling quality request enhancement, the simple mechanical type steering system were already unable to meet the needs, the power steering system arise at the historic moment, it could rotate the steering wheel while the pilot to provide the boost, the power steering system divides into the hydraulic pressure steering system and the electrically operated steering system 2kinds.Hydraulic pressure steering system is at present uses the most widespread steering system.The hydraulic pressure steering system increased the hydraulic system in the mechanical system foundation, including hydraulic pump, V shape band pulley, drill tubing, feed installment, boost installment and control valve. It with the aid of in the motor car engine power actuation hydraulic pump, the air compressor and the generator and so on, by the fluid strength, the physical strength or the electric power increases the pilot to operate the strength which the front wheel changes, enables the pilot to be possible nimbly to operate motor turning facilely, reduced the labor intensity, enhanced the travel security.The hydraulic pressure boost steering system from invented already had about half century history to the present, might say was one kind of more perfect system, because its work reliable, the technology mature still widely is applied until now. It takes the power supply by the hydraulic pump, after oil pipe-line control valves to power hydraulic cylinder feed, through the connecting rod impetus rotation gear movement, may changes the boost through the change cylinder bore and the flowing tubing head pressure size the size, from this achieved changes the boost the function. The traditional hydraulic pressure type power steering system may divide into generally according to the liquid flow form: Ordinary flow type and atmospheric pressure type 2 kind of types, also may divide into according to the control valve form transfers the valve type and the slide-valve type.Along with hydraulic pressure power steering system on automobile daily popularization, the people to operates when the portability and the road feeling request also day by day enhance, however the hydraulic pressure power steering system has many shortcomings actually: Because its itself structure had decided it is unable to guarantee vehicles rotates the steering wheel when any operating mode, all has the ideal operation stability, namely is unable simultaneously to guarantee time the low speed changes the portability and the high speed time operation stability;The automobile changes the characteristic to drive the pilot technical the influence to be serious; The steering ratio is fixed, causes the motor turning response characteristic along with changes and so on vehicle speed, transverse acceleration to change, the pilot must aim at the motor turning characteristic peak-to-peak value and the phase change ahead of time carries on certain operation compensation, thus controls the automobile according to its wish travel. Like this increased pilots operation burden, also causes in the motor turning travel not to have the security hidden danger; But hereafter appeared the electrically controlled hydraulic booster system, it increases the velocity generator in the traditional hydraulic pressure power steering system foundation, enables the automobile along with the vehicle speed change automatic control force size, has to a certain extent relaxed the traditional hydraulic pressure steering system existence question.At present our country produces on the commercial vehicle and the passenger vehicle uses mostly is the electrically controlled hydraulic pressure boost steering system, it is quite mature and the application widespread steering system. Although the electrically controlled hydraulic servo alleviated the traditional hydraulic pressure from certain degree to change between the portability and the road feeling contradiction, however it did not have fundamentally to solve the HPS system existence insufficiency, along with automobile microelectronic technology development, automobile fuel oil energy conservation request as well as global initiative environmental protection, it in aspect and so on arrangement, installment, leak-proof quality, control sensitivity, energy consumption, attrition and noise insufficiencies already more and more obvious, the steering system turned towards the electrically operated boost steering system development.The electrically operated boost steering system is the present motor turning system development direction, its principle of work is: EPS system ECU after comes from the steering wheel torque sensor and the vehicle speed sensor signal carries on analysis processing, controls the electrical machinery to have the suitable boost torque, assists the pilot to complete changes the operation. In the last few years, along with the electronic technology development, reduces EPS the cost to become large scale possibly, Japan sends the car company, Mitsubishi Car company, this field car company, USs Delphi automobile system company, TRW Corporation and Germanys ZF Corporation greatly all one after another develops EPS.Mercedes2Benz 和Siemens Automotive Two big companies invested 65,000,000 pounds to use in developing EPS, the goal are together load a car to 2002, yearly produce 300 ten thousand sets, became the global EPS manufacturer. So far, the EPS system in the slight passenger vehicle, on the theater box type vehicle obtains the widespread application, and every year by 300 ten thousand speed development.Steering is the term applied to the collection of components, linkages, etc. which allow for a vessel (ship, boat) or vehicle (car) to follow the desired course. An exception is the case of rail transport by which rail tracks combined together with railroad switches provide the steering function.The most conventional steering arrangement is to turn the front wheels using a handoperated steering wheel which is positioned in front of the driver, via the steering column, which may contain universal joints to allow it to deviate somewhat from a straight line. Other arrangements are sometimes found on different types of vehicles, for example, a tiller or rearwheel steering. Tracked vehicles such as tanks usually employ differential steering that is, the tracks are made to move at different speeds or even in opposite directions to bring about a change of course.Many modern cars use rack and pinion steering mechanisms, where the steering wheel turns the pinion gear; the pinion moves the rack, which is a sort of linear gear which meshes with the pinion, from side to side. This motion applies steering torque to the kingpins of the steered wheels via tie rods and a short lever arm called the steering arm.Older designs often use the recirculating ball mechanism, which is still found on trucks and utility vehicles. This is a variation on the older worm and sector design; the steering column turns a large screw (the worm gear) which meshes with a sector of a gear, causing it to rotate about its axis as the worm gear is turned; an arm attached to the axis of the sector moves the pitman arm, which is connected to the steering linkage and thus steers the wheels. The recirculating ball version of this apparatus reduces the considerable friction by placing large ball bearings between the teeth of the worm and those of the screw; at either end of the apparatus the balls exit from between the two pieces into a channel internal to the box which connects them with the other end of the apparatus, thus they are recirculated.The rack and pinion design has the advantages of a large degree of feedback and direct steering feel; it also does not normally have any backlash, or slack. A disadvantage is that it is not adjustable, so that when it does wear and develop lash, the only cure is replacement.The recirculating ball mechanism has the advantage of a much greater mechanical advantage, so that it was found on larger, heavier vehicles while the rack and pinion was originally limited to smaller and lighter ones; due to the almost universal adoption of power steering, however, this is no longer an important advantage, leading to the increasing use of rack and pinion on newer cars. The recirculating ball design also has a perceptible lash, or dead spot on center, where a minute turn of the steering wheel in either direction does not move the steering apparatus; this is easily adjustable via a screw on the end of the steering box to account for wear, but it cannot be entirely eliminated or the mechanism begins to wear very rapidly. This design is still in use in trucks and other large vehicles, where rapidity of steering and direct feel are less important than robustness, maintainability, and mechanical advantage. The much smaller degree of feedback with this design can also sometimes be an advantage; drivers of vehicles with rack and pinion steering can have their thumbs broken when a front wheel hits a bump, causing the steering wheel to kick to one side suddenly (leading to driving instructors telling students to keep their thumbs on the front of the steering wheel, rather than wrapping around the inside of the rim). This effect is even stronger with a heavy vehicle like a truck; recirculating ball steering prevents this degree of feedback, just as it prevents desirable feedback under normal circumstances.The steering linkage connecting the steering box and the wheels usually conforms to a variation of Ackermann steering geometry, to account for the fact that in a turn, the inner wheel is actually traveling a path of smaller radius than the outer wheel, so that the degree of toe suitable for driving in a straight path is not suitable for turns.As vehicles have become heavier and switched

温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。