steering axis inclination
toe-out on turns tipping effect thrust angle wheel tracking dog tracking eccentric cam
转向轴线内倾角
转Hale Waihona Puke 负前束 侧倾效应 推力角，推力线 （前轮与后轮）同辙行驶 蛇形行驶 偏心凸轮
scraping scrubbing imaginary deviation
['skreipiŋ]
n.刮, 擦
[skrʌbiŋ]
n.洗擦, 擦净
[i'mæ ʤinəri] a.假想的, 想象的, 虚构的
[ֽdi:vi'ei∫ən] n.背离，偏离
chisel
['t∫izl]
eccentric [ik'sentrik]
159 Adjustable front wheel settings on most modern vehicles are caster, camber, and toe. Nonadjustable settings are steering axis inclination and toe-out on turns. Rear wheel settings that can be made on many modern vehicles are camber and toe. Modern practice is to check both front and rear wheel alignment. Note that the various alignment angles are all related. A change in one can alter the others. Alignment Measurement Values 14 All alignment values, except for toe, are measured in degrees. Toe is measured in fractions of an inch or millimeters. Caster 15 Positive caster tends to force the wheels to travel in a straight ahead position. It also assists in recovery (wheels turning back to straight ahead position) after making a turn. On late model cars, there is often little or no positive caster. Positive caster makes it more difficult to turn the wheels from the straight ahead position than when no caster angle is present [1].
本次课学习目标
掌握车轮定位的英文专业词汇 训练快速阅读能力，提高阅读速度
NEW WORDS
wandering provision misalign setting
['wɔndəriŋ] [prə'viƷən] ['misəlain] ['setiŋ]
caster camber toe toe-out toe-in offset
Steering Axis Inclination 42 The steering knuckle ball joints are closer together at the top than the bottom. The steering axis (view from the front of the car) places the centerline of the steering ball joints closer to the centerline of the wheel. This angle is known as steering axis inclination, or SAI. 43 When the wheel centerline is to the outside of the center line of the steering axis (where they intersect the road), the wheels tend to toe-out. This is caused by the road-tire resistance pushing back on the spindle, causing it to swivel backward on the ball joints or toe-out. When the centerline of the wheel intersects the road at a point inside of the steering axis centerline intersection, the wheels tend to toe-in (tires are closer together in the front than in the back).
17 Another aspect of positive caster is a mild tipping effect when cornering. When making a right turn, the right wheel will cause the steering knuckle to raise slightly, while the left wheel will allow the knuckle to lower, creating the tipping effect. If the left side of the vehicle was allowed to rise during a right turn, it would have an adverse effect on the vehicle's cornering ability. 18 To ease turning, many cars employ a negative caster angle, which angles the top of the steering knuckle to front of car. This will ease steering while also causing the mild tipping effect needed when cornering. Camber 19 Camber is the tilting of the wheel centerline, viewed from the front of the vehicle, away from a true vertical line. Camber angles are usually small, usually no more than 1º positive or negative from zero. An incorrect camber setting will cause pulling and tire wear.
PROFESSIONAL ENGLISH
UNIT 11 SUSPENSION AND STEERING SYSTEMS
TEXT C
Wheel Alignment
本次课学习内容
TEXT A Wheel Alignment
• Alignment Measurement Values • Front Wheel Alignment Adjustments • Rear Wheel Alignment Adjustments • Alignment Equipment
Wheel Alignment 4 Wheel alignment is the process of measuring and correcting the various angles formed by the front and rear wheels, spindles, and steering arms. Correct alignment is vital. Improper alignment can cause hard steering, pulling to one side, wandering, noise, and rapid tire wear. Types of Wheel Alignment 11 Rear-wheel drive vehicles require a two-wheel alignment or front-wheel alignment only. The rear wheels are attached to a solid rear axle assembly which cannot be adjusted, and generally stays in alignment throughout the life of the vehicle. 12 Today, most front-wheel drive vehicles have provisions for adjusting the rear wheels. In addition, many rear-wheel drive vehicles are equipped with independent rear suspensions, which also must be adjusted. Also, modern solid rear axles and suspension systems are lightweight and can become misaligned. Therefore, the four-wheel alignment, in which the front and rear wheel alignment angles are checked and adjusted, is commonly performed.