Hydraulic power steering system
Hydraulic power feels dull. Whether it is driving at high speed or low speed, the boosting effect of hydraulic boost is fixed. This caused the steering wheel to be too sensitive when driving at high speeds, greatly reducing the handling and safety of driving. This is why many pickup users are eager for electric assistance.
The main components of the hydraulic power steering system are hydraulic pumps, oil pipes, pressure fluid control valves, V-shaped drive belts, oil storage tanks, etc. The power source of this system is the engine. The engine drives the steering oil pump to work. The steering control valve controls the direction of oil flow and the size of the oil pressure.
Electronic hydraulic power steering system
Electro-hydraulic assistance is now a wasteful design. In short, it is an electronically controlled hydraulic system. Compared with hydraulic boost, it can transmit the vehicle speed signal to the ECU, and then to the control system to adjust the boost effect. Its most representative pickup is the Ford Ranger.
The system has a large power-assistance effect at low speeds, and the driver is light and flexible. The power-assistance effect is weakened at high speeds. The driver's control power is increased, and the road feel is obvious. It not only ensures the comfort and flexibility of steering operation, but also improves It improves steering stability and safety during high-speed driving. However, the electronically controlled hydraulic system has a complicated mechanism and is expensive. It still overcomes the shortcomings of the hydraulic power steering system, such as low efficiency, large energy consumption, and oil pollution.
Electric power steering system
Electric power assist is a steering system that uses electric motors to assist it. Compared with hydraulic power assistance, it completely meets the needs of different power assistance effects at different speeds. Compared with electro-hydraulic assist, it has higher efficiency and lower energy consumption.
As shown in the figure above, the system works as follows: the output torque of the motor acts on the steering column through the reduction mechanism, and the product of the output torque of the motor and the reduction ratio of the reduction mechanism is the assist torque of the motor. The driver's steering torque, together with the motor assist torque, overcomes the tire's return torque and the friction torque of the steering system to achieve real-time control of the power steering.
At present, only domestic SAIC Chase T60 and T70 models are the only domestic brand pickup trucks; the Great Wall Artillery Passenger Pickup trucks are all models; some Jiangxi Isuzu extensions are equipped with electric power steering systems.
Active front wheel steering system
Compared with the auxiliary steering system, the active front wheel steering system is more intelligent. According to the driver's driving intention, the system can use the motor to apply an additional turning angle to the front wheels that does not rely on the input of the driver's steering wheel to correct the driver's steering angle, control the vehicle in time, and actively improve the maneuverability of the vehicle. , Stability and trajectory retention performance to achieve active steering.
Steer-by-wire
Exaggeratedly, in the on-line steering system, we are only a signal, and even turning the steering wheel is no different from pressing the arrow keys on the keyboard. Because the steer-by-wire system cancels the mechanical connection between the steering wheel and the steering wheel, the driver's steering operation and the steering wheel are connected by signals and controllers. The driver's steering operation only inputs driving instructions to the vehicle. According to the driver's instructions, the controller determines a reasonable front wheel rotation angle based on the current vehicle state and road conditions. The intelligent control of the steering system is implemented to improve the stability of the vehicle and reduce the driver's Manipulating the burden.