汽车专业英语第五章

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。
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90º 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 (or wheel swivel axis centers). 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。
recirculation ball
Most heavy commercial vehicles use the recirculation ball type of steering gear. This steering gear is durable, with good steering response and good road feel for the driver.
To minimize tire wear the front wheels should be steered from the straight ahead to a position where they form an angle of 90º a line drawn from the to instantaneous center to the wheel center. It means that the inner wheel turns through a larger angle than the outer wheel.
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转向节 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。
The main types of Steering Box.
recirculation ball rack and pinion
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 recirculation ball steering gear, the wormshaft is the input shaft. The wormshaft connects to the steering columnin 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.
5.4.3 Hydraulic Power Assisted Steering
1. Energy Source The pump－usually a vane-type pump with internal bypass－must 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-1at 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.
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.
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.
CHAPTER 5
STEERING AND SUSPENSION SYSTEM
5.1 Basic parts of steering system
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.
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．转向盘转动齿轮．齿条是一 个一面有齿长平杆．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，转向器和反馈和路感．
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
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 parts－the 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.