wheel

In addition to the traditional steering wheel, the latter two wheels are also steering wheels, that is, four-wheel steering, which began to develop in the mid-1980 s. Its main purpose is to improve the handling stability of the car under the action of high speed or crosswind, improve the handling portability at low speed and reduce the turning radius of the parking lot. There are two main ways of four-wheel steering: when the rear wheel steering and the front wheel steering are in the same direction, it is called co-steering; When the rear wheel turns in the opposite direction to the front wheel, it is called reverse steering.

The four-wheel steering system has the following obvious advantages:

First of all, when turning, it can basically keep the sideslip angle of the vehicle center of mass zero, and improve the dynamic response characteristics of the vehicle to the input of the steering wheel, improve the transient response performance index of yaw rate and lateral acceleration to a certain extent, and obviously improve the stability of the vehicle at high speed. During high-speed steering, the four-wheel steering system can effectively reduce/eliminate the probability of vehicle side-slip accidents by synchronously steering the rear wheel and the front wheel, obviously improve the stability and safety of vehicles driving at high speed, and further alleviate the fatigue of drivers in various road conditions (especially in rainy days).

Secondly, reduce the turning radius when the vehicle turns at low speed. When turning at low speed, the turning radius of the vehicle can be reduced by 20% due to the reverse steering of the front and rear wheels. Four-wheel steering technology makes large vehicles have the same agility of handling and parking as small vehicles.

Thirdly, the trailer capacity of the vehicle is improved. Through the steering traction of the rear axle to the trailer, the follow-up and correctness of the steering operation are greatly improved, and the maneuverability, stability and safety of the vehicle trailer are improved.