【Listening】

【Vocabulary & Phrases】

spring弹簧

shock absorber减震器

anti-sway bar 横向稳定杆

coil spring螺旋弹簧

leaf spring钢板弹簧

torsion  bar扭杆弹簧、扭力杆

air spring空气弹簧

independent suspension独立悬架

hydraulic action液压作用

【Reading】

SuspensionSystem

Suspension components

There are three fundamental components p of anysuspension: springs, shock absorber and anti-sway bar.

1.Springs

The springs are a very important component of thesuspension system that provides ride comfort. The springs support the weight ofthe car, maintain ride height, and absorb road shock. Springs are thecompressible link between the frame and the body. When the car meets a bump inthe road, the springs will absorb the load by compressing. There are four majorspring designs in use today: coil spring, leaf spring, torsion bar, and airspring.

 1）Coil Spring

This is the most common type of spring. The coilspring is a length of round spring steel rod that is wound into a coil. Coilsprings compress and expand to absorb the motion of the wheels. It requires noadjustment and for the most part is trouble-free.

Most automotive vehicles have independent frontsuspension usually using coil springs as part of either a short-arm/long-arm ora MacPherson-strut suspension system. A MacPherson-strut suspension（seeillustration）combinesa coil spring and shock absorber into a strut assembly that requires only abeam-type lower control arm.

2）Leaf Spring

This type of spring consists of several layers ofsteel plates (called “leaves”)of different lengths stacked together to act as asingle unit. The leaf springs bend and slide on each other allowing suspensionmovement. They are still used today on most trucks and heavy-duty vehicles.

3）Torsion Bar

The torsion bar is a straight or L shaped bar ofspring steel. One end of a bar is anchored to the vehicle frame. The other endattached to a wishbone. When the wheel hits a bump, vertical motion istransferred to the wishbone and then, through the levering action, to thetorsion bar providing spring action.

Most automobiles and many light trucks have coilsprings at the rear. These may mount on the rear drive axle, on struts, or onvarious types of control or suspension arms in an independent suspensionsystem. Some rear-drive vehicles have leaf springs at the rear. Others usetransverse torsion bars.

4）Air Spring

The air spring is another type of spring that isbecoming more popular on passenger cars. The air spring is a rubber cylinderfilled with compressed air. A piston attached to the lower control arm moves upand down with the lower control arm. This causes the compressed air to providespring action.

2.Shock Absorber

Shock absorber is a device that controls unwantedspring motion, which is important in keeping the tires in firm contact with theroad. The shock absorber contains a piston that moves in a cylinder as thewheel moves up and down with respect to the vehicle body or frame. As thepiston moves, it forces a fluid through an orifice, imposing a restraint on thespring.

Shock absorbers are used to absorb energy developedin the springs or torsion bars when the wheels of an automobile move up anddown. The energy is absorbed by means of hydraulic action. The lower end of ashock absorber is mounted on a control arm (or on an extension of the U-boltplate if it is a rear shock absorber used with a leaf spring), and the upperend is mounted on the frame or one of its cross members.

3.Anti-sway Bar

Another important component of a suspension systemis the anti-sway bar. This device is used along with shock absorbers to give amoving car additional stability. The anti-sway bar is simply a metal rodconnected to both of the lower control arms.

When the suspension at one wheel moves up and downthe anti-sway bar transfers the movement to the other wheel. This creates amore level ride and reduces vehicle sway. In particular, it combats the roll ofa car on its suspension as it corners. For this reason, almost all cars todayare fitted with anti-sway bars as standard equipment, although if they’re not,kits make it easy to install the bars at any time.

【随堂测试】