汽车专业英语(幻灯片)chapter 5 steering system.ppt

Review 1:Whats the function of Steering system?,To convert the steering-wheel rotary motion into a turn motion of the steered wheels of the vehicle.To guide the car where the driver wants it to go.,转向器Steering box/gear,转向摇臂Pitman/Drop arm,转向直拉杆Drag link,转向节臂Steering arm,转向节Steering knuckle,梯形臂Track arm,横拉杆Track rod,Review 2:Basic parts of steering system,转向轴Steering axle,方向盘Steering wheel,转向万向节steering shaft universal joint,steering control mechanism 转向操纵机构 Steering gear 转向器 Steering linkage 转向传动机构,梯形臂Track arm,The basic steering system in most cars is the same.The steering gear of steering box is the heart of the steering system.This usually is next to the engine.A shaft extends from the back of the steering gear.This shaft is connected to the steering column or steering shaft.The steering wheel is at the top of the steering column.Another shaft comes from the bottom of the steering gear.This shaft connects to the arms,rods,and links.This parts assembly,called the steering linkage,connects the steering gear to the parts at the wheels.The wheels and tires mount to the steering knuckles.As shown in Fig.5-1,the knuckles are pivoted at the top and bottom.Thus,the wheels and tires can turn from side to side.,多数汽车的转向系基本上是一样的。转向系的核心是转向器，一般位于发动机附近。一根轴从转向器后部伸出，连接着转向柱。方向盘在转向柱的顶端。另一根轴从转向器低端伸出，连接着转向臂、转向拉杆和转向杆系，这些部件总称为转向传动机构，连接转向器和车轮上的部件。车轮和轮胎安装在转向节上。如图5-1所示，转向节的上下端可自由转动，这样车轮可从一侧转到另一侧。,While the steering system may look complicated,it works quite simply.When a driver drives a car straight down the road,the steering gear is centered.The gear holds the linkage centered so that the wheels and tires point straight ahead.When the driver turns the steering wheel,the steering shaft rotates and the steering gear moves toward that side.The shaft coming out the bottom of the steering gear turns,as well.When the shaft turns,it pulls the linkage to one side and makes the steering knuckles turn slightly about their pivot points.Thus,the steering knuckle,spindle,wheels,and tires turn to one side,causing the car to turn.,转向系看起来复杂，工作原理却很简单。汽车直行时，转向器处于中间位置，转向传动机构也处于中间位置，车轮直行。驾驶员转动方向盘，转向轴旋转，转向器向同侧转动，同时转向器底部的输出轴也会旋转。输出轴转动时，会向一侧拉动拉杆，使得转向节绕其支点旋转。这样，转向节、转向节轴端、车轮和轮胎都会向一侧旋转，汽车实现转向。,Review 2:How the of Steering System works?,Review 3:How does the Steering System work?,Review 3:How does the Steering System work?,Review 4:Whats the meaning of Steering Geometry?,CotCotBL,To minimize tire wear the front wheels should be steered from the straight ahead to a position where they form an angle of 90 to a line drawn from the instantaneous center to the wheel center.It means that the inner wheel turns through a larger angle than the outer wheel.,为减少轮胎的磨损，前轮应该从前进方向转到和瞬时转动中心到车轮中心的连线成90角的位置，这表明内侧车轮比外侧车轮转过的角度要大。,It is obtained by making the track rod a different length to the distance between the king pins.The track rod length is set so that its connection to the track arm falls on an imaginary line taken from the king pin to a point on the vehicle center line just in front of the rear axle.,转向横拉杆的长度同主销间的距离不相等，就可保证各前轮以期望的角度旋转。转向横拉杆长度的设置要保证转向横拉杆与梯形臂的连接点位于主销到后桥前端汽车中心线上的点所形成的假想连线上。,Review 5:List the main types of Steering Box.,recirculation ball循环球转向器,rack and pinion齿轮齿条转向器,Worm and peg 蜗杆曲柄指销式,Worm and roller 蜗杆蜗轮式,recirculation ball,Most heavy commercial vehicles use the recirculating ball type of steering gear.This steering gear is durable,with good steering response and good road feel for the driver.,多数重型商用车采用循环球式转向器，这类转向器性能稳定、转向灵敏而且路感好。,In the recirculating ball steering gear,the wormshaft is the input shaft.The wormshaft connects to the steering column in such a way that a mechanic can remove the steering gear or steering column independently of one another.The sector shaft(also called the pitman shaft)is like the output shaft of the steering gear.The main parts of the steering gear are the balls,ball nut,and the gear teeth on the ball nut.,在循环球式转向器中，转向螺杆是输入轴。这样转向螺杆连接着转向柱，修理工就可独立拆卸转向器或转向柱。齿扇轴（也叫摇臂轴）相当于转向器的输出轴转向器的主要部件是钢球，转向螺母和转向螺母上的齿,As the wormshaft turns,the balls move the ball nut up and down along the wormshaft.This turns the sector shaft,since the sector teeth mesh with the ball nut teeth.The sector shaft is connected through steering linkage to the front wheels.,As the wormshaft turns,the balls move the ball nut up and down along the wormshaft.This turns the sector shaft,since the sector teeth mesh with the ball nut teeth.The sector shaft is connected through steering linkage to the front wheels.,当转向螺杆转动时，刚球使球螺母沿转向螺杆上下运动由于扇齿与球螺母齿啮合，齿扇轴转动齿扇轴通过转向传动机构与前轮连接,rack and pinion,The rack-and-pinion system has two main partsthe pinion and the rack.The pinion is on the end of the steering column.The steering wheel turns the pinion.The rack is a long,flat bar with teeth on one side.The rack teeth mesh with the teeth on the pinion.,齿轮齿条转向器有两个主要部件齿轮和齿条齿轮安装在转向柱的末端方向盘带动齿轮转动齿条是一个一面有齿的长平杆齿条与齿轮啮合,Rack-and-pinion steering is used on many new smaller cars and on most cars with a transverse engine.This steering gear is small and lightweight.It provides good steering with minimum driver effort.Also,rack-and-pinion steering needs fewer parts in the steering gear and linkage.Thus,it is easy to service.Rack-and-pinion steering gives more feedback and road feel to the driver.,很多新型小汽车和多数发动机横置的汽车都采用齿轮齿条式转向器。这类转向器尺寸小、重量轻，而且转向轻便。另外，转向器和转向传动机构所需的部件较少，便于维修。齿轮齿条式转向器为驾驶员提供了较好的反馈和路感,Rotation of the pinion moves the rack from left to right and right to left,the motion of the rack causes the steering linkage to move back and forth,then causes the wheels to turn to the left or right.,Hydraulic Power Assisted Steering(HPAS)液压助力转向系统Electro-Hydraulic Power Steering（EHPS）液压电动转向系统Electric Power Assisted Steering（EPAS 或EPS）电动助力转向系统Active Front Steering（AFS）主动前轮电动转向系统Electric Power Steering by wire（EPS-by wire或SBW）线控电动转向系统,齿轮齿条Rack and pinion,叶片泵Oil pump,流量控制阀Flow-limiting valve,储液罐Oil reservoir,Hydraulic Power Assisted Steering,动力缸Steering cylinder,活塞Power Piston,扭杆torsion bar,转向控制阀 Control valve（Sleeve and Rotor）,The pumpusually a vane-type pump with internal bypassmust be dimensioned such that,even with the engine idling,it delivers a flow of oil with which it is possible to achieve a steering-angle velocity of at least 1.5 s-1 at the steering wheel.At higher engine speeds a further rise in the pressure of the oil flow is prevented by a flow-limiting valve integrated in the pump.这种泵通常是内部有旁通管路的叶片泵，它的尺寸已定，这样即使发动机空转时，它不断的输送油液使方向盘达到至少1.5 s-1转向角速度发动机转速较高时，装在泵中的流量控制阀阻止了油压进一步增加,The double-acting steering cylinder converts the applied oil pressure into an assisting force which acts on the rack and which intensifies the steering force exerted by the driver.The steering cylinder is normally integrated in the steering box.双动的动力缸将施加的油压转换成助动力，作用在齿条上，加强了驾驶员施加的转向力。动力缸通常安装在转向器中。,Electric Power Assisted Steering,The EPAS system is replacing the hydraulic steering system and is destined to soon become mainstream among automotive manufacturers.Electric power assisted steering systems do not require engine power to operate.Thus,a vehicle equipped with an EPAS system may achieve an estimated three percent greater fuel economy than the same vehicle with conventional hydraulic power steering.电动转向助力系统正逐步代替液力转向系统并在汽车制造业中很快成为主流电动转向助力系统不需要发动机动力驱动这样，装备电动转向助力系统的汽车可以比装液力转向系统的同类型车辆节约大约的燃油,The benefits of EPAS compare to HPAS:Reducing system mass compared to HPAS;Reducing fuel consumption;Offering a lower cost solution than HPAS;Increasing the flexibility of component placement by removing the hydraulic system.,Active Front Steering,主动前轮电动转向系统,At low-speed driving in city traffic,when much steering work is necessary,the use of the electric motor provides for a smaller number of steering wheel turns with the same effort required.At high speeds,however,the driver no longer needs to fear that he or she will lose control of the vehicle as a result of a steering motion.在市内运输中低速行驶需要大的转向操作，使用电动机，方向盘转动较小角度就可以得到同样的转向力高速行驶时，驾驶员不必再担心转向引起车辆失去控制,The Active steering is a first step to the steer by wire function;so fundamental steer by wire functions can definitely be implemented at this early stage,also with regard to the capability of integration into a net work and signal processing.主动电动转向系统是实现线控转向功能的第一步，线控转向的基本功能，也就是关于网络和信号处理一体化的能力，在这一步得到明显的应用,线控转向系统(SBW),