1、 附录：外文资料 Automotive Suspension System Overview The impact of the Vehicle in many aspects, Suspension plays a very important role . The components of the suspension system perform six basic functions: 1.Maintain correct vehicle ride height. 2.Reduce the effect of shock forces. 3.Maintain correct whee
2、l alignment. 4.Support vehicle weight. 5.Keep the tires in contact with the road. 6.Control the vehicles direction of travel. Most suspension systems have the same basic parts and operate basically in the same way. They differ, however, in the way the parts are arranged. The vehicle wheel is attache
3、d to a steering knuckle. The steering knuckle is attached to the vehicle frame by two control arms, which are mounted so they can pivot up and down. A coil spring is mounted between the lower control arm and the frame. When the wheel rolls over a bump, the control arms move up and compress the sprin
4、g. When the wheel rolls into a dip, the control arms move down and the springs expand. The spring force brings the control arms and the wheel back into the normal position as soon as the wheel is on flat pavement. The idea is to allow the wheel to move up and down while the frame, body, and passenge
5、rs stay smooth and level. The unequal length control arm or short, long arm (SLA) suspension system has been common on American vehicles for many years. Because each wheel is independently connected to the frame by a steering knuckle, ball joint assemblies, and upper and lower control arms, the syst
6、em is often described as an independent suspension. The short, long arm suspension system gets its name from the use of two control arms from the frame to the steering knuckle and wheel assembly. The two control arms are of unequal length with a long control arm on the bottom and a short control arm
7、 on the top. The control arms are sometimes called A arms because in the top view they are shaped like the letter A. In the short, long arm suspension system, the upper control arm is attached to a cross shaft through two combination rubber and metal bushings. The cross shaft, in turn, is bolted to
8、the frame. A ball joint, called the upper ball joint, is attached to the outer end of the upper arm and connects to the steering knuckle through a tapered stud held in position with a nut. The inner ends of the lower control arm have pressed-in bushings. Bolts, passing through the bushings, attach t
9、he arm to the frame. The lower ball joint is usually pressed into the control arm and connects to the steering knuckle through a tapered stud that is held in position with a nut. A ball joint is used on the control arms because it allows movement in more than one direction. It allows the up-and-down
10、 motion required as the wheels pass over dips and bumps. This type of joint also allows side-to-side motion as the wheels are turned back and forth for turns. For the upper and lower ball joint, the ball stud in the ball joint is a tapered stud at one end with a ball-shaped end. The ball end is supp
11、orted in a similarly shaped housing called a socket. The shape of the housing allows the ball stud to turn around or move side to side. A plastic or sintered iron bearing is positioned between the ball and socket .The bearing allows the ball stud to turn in relation to the housing for steering. The
12、tapered stud and nut hold the ball joint in position in the steering knuckle. There are four basic types of springs used in suspensions: coil, torsion bar, leaf spring, and air spring. The coil spring is the most popular type of spring in both front and rear suspension systems. It is simply a round
13、bar of spring steel that is wound into the shape of a coil. Usually, the top and bottom coils are closer together than the middle coils. A coil spring is commonly used on the short, long arm suspension system. Some cars have the spring mounted from the frame to the upper control arm. In either case,
14、 the shock absorber is mounted through the center of the spring. Most short, long arm systems use a stabilizer bar between the two sides of the suspension. The sway bar connects both lower control arms to the frame crossmember. Movements affecting one wheel are partially transmitted to the opposite
15、wheel through the frame to stabilize body roll. The sway bar is attached to the frame crossmember and lower control arms through rubber insulator bushings to reduce noise and vibrations. Sway bar end bushings and crossmember bushings are permanently installed on the sway bar. The advantages of the c
16、oil spring are its compactness, lack of moving parts, and excellent weight supporting characteristics. The disadvantage of a coil spring is its weakness in supporting side-to-side or lateral movement. When coil springs are used at the drive wheels, heavy traction bars or torque tubes are often requi
17、red to maintain axle housing alignment. A number of vehicles use a torsion bar spring. It is a long, solid steel shaft that is anchored at one end to the suspensions control arm and at the other end to the vehicles frame. Torsion is the twisting action that occurs in the bar when one end is twisted and the other end remains fixed. When a vertical impact on a wheel is transmitted through the control arm to the torsion bar, the bar twists to absorb the
