FRONT END GEMOETRY AND WHEEL ALIGNMENT
In order to take into account the various features that constitute the steering or front end geometry of a vehicle, it is necessary not only to consider the system in plan view as related to Ackermann effect, but also in end and side views. Considered in end or front view, the orientation of the steered wheels both with respect to the road surface and to their swivel axis is defined in terms of camber angle, king-pin inclination and steering offset. In side view, it is the angular disposition of the swivel axis relative to the vertical that we are concerned with, and which is termed castor angle.
This is the inclination of the road wheel centre plane relative to the vertical, as viewed from the front of the vehicle (Figures 24.9a and 24.10a). The camber angle is considered to be positive if the top of the wheel leans outwards and negative if it leans inwards . Historically, a noticeably positive camber was given to the front wheels of motor cars of an earlier era (as any reader who has ever seen one of the legendary prewar Bugatti cars head on will agree!), its purpose being to maintain the wheels normal to the surface of the then steeply cambered or crowned single-track roads.
In modern automotive practice, however, the front wheels are usually provided with either a zero or a small camber angle of up to about 1度 positive, at the normal standing height of the vehicle. The tendency of a cambered wheel to roll in a direction towards which it is leaning, thereby producing a side force or camber thrust, can have two beneficial effects on the steerable wheels. First, it tends to counteract any small sideways forces imposed on the tyres by ridges in the road, and second, it induces a small lateral preload in the steering linkage. The overall effect is therefore to promote stable, straight-ahead running.
- 9 years agoFavorite Answer
在現代汽車，但實際上，前輪通常提供了無論是零或一小傾角高達約 1度陽性，在正常站立高度的車輛。這種傾向的一個弧形車輪滾動的方向，為此它是學習，從而產生一個側向力或拱的推力，可以有兩個有利影響的可操縱輪。首先，它往往以抵消任何小側身勢力強加給輪胎的山脊在路上，二，歸納在一個小的預側轉向聯動。因此，總的效果是促進穩定，筆直向前運行。Source(s): Google 軟體