汽车专业英语 教学课件 ppt 作者 廖忠诚 杨晓波 主编Chapter3 Steering and Suspension.pptVIP

3.1 Steering System 3.1.1 Principle Of Steering And Steering Gearbox The direction of motion of a motor vehicle is controlled by a steering system. The steering system must provide control over the direction of travel of the vehicle, good manoeuvrability, smooth recovery from turns, and minimum transmission of road shocks from the road surface. system are designed according to the use requirements of the vehicle. They can be in single or multi-axle designs. A basic steering system has 3 main parts: Steering wheel and steering column, A steering box connected to the steering wheel. The linkage connects the steering box to the wheel assemblies at the front wheels. And front suspension parts let the wheel assemblies pivot (see fig.3-1) 1,6-steering knuckle 2-drag linkage 3-front axle 4,10- steering box 5- steering column 7-steering wheel 8,12- steering arm 9- tie-rod 11- pitman arm 3.1.2 Power Steering Systems With heavier vehicles, increased use of front-wheel-drive, and wider, low-profile tyres, more steering effort is needed, so power steering is used. Power steering systems produce assistance that reduces the drivers effort. They are of most benefit during slow cornering and when parking. Assistance is provided as soon as the steering wheel is rotated in either direction, and it’s designed so that even if system failure occurs, the vehicle can still be steered. Hydraulic power steering system Hydraulic power steering systems are hydraulic mechanical unit with an integral steering gearbox assembly. A hydraulic pump is driven from the engine, to provide pressure to help the driver steer the vehicle. The pump is normally a vane-type, with sufficient capacity for all operating conditions.Hydraulic pump delivers hydraulic fluid to the power unit at the steering box, through connecting hoses and pipes. With the engine running, fluid flows continuously from the power steering pump, to the steering gear, and back to the pump.