For civilian cars, slight understeer characteristics can guarantee the stability of the vehicle, but tend to produce excessive steering vehicle speed when turning, so the rear wheel steering system, can make up for this excessive steering driving risk brings, while for large cars and luxury cars, the rear wheel steering can make the vehicle more flexible at low speed high speed, cornering is more stable, to drive the same fun.

Three turning characteristics of vehicle

Before turning to the specific questions, let's talk about the turning characteristics of the vehicle. The characteristics of the steering can be divided into three kinds of situations, which are insufficient, neutral and over turning.

The performance of the vehicle understeer in the actual bending rotation angle of the front wheel steering angle is small, the front wheel is also appeared to the outside of the turning slide, also known as the "tuitou".

Steering excessive performance for the vehicle in the actual steering angle of the steering angle than the rotation angle of the front wheel, that is, the rear wheel to the outside of the slide.

The performance of the actual vehicle in neutral steering curve of the steering angle is exactly the rotation angle of the front wheel, the steering characteristic can often reach maximum turning speed, but this also reduces the subjective feeling of the driver of the vehicle to a certain extent, close to the physical limits of the.

For the former car, when there is insufficient to turn, you can solve the problem by reducing the speed. However, if there is a serious turn over the need to reverse the direction and with the refueling to pass, which is the skill of drift, but this is very high demand for motorists. Therefore, in general, the general civil vehicle in the steering characteristics of the school will be biased towards a slight shift to ensure the stability of the ride.

Effect of rear wheel steering on vehicle steering characteristics

After understanding the steering characteristics of the vehicle, we look at the rear wheel steering on the vehicle's overall steering characteristics will produce what kind of impact. The rear wheel steering is in the same direction as the front wheel and the reverse two cases, and these two kinds of conditions also show two completely different steering characteristics. In simple terms, the same direction to increase the lack of steering, reverse increase over the steering. When the vehicle is running at low speed, the steering wheel can be turned over by the reverse rotation of the rear wheel and the front wheel. The high-speed vehicle emergency lane change situation, in the absence of any electronic auxiliary system, it is prone to oversteer tendency through the rear wheels produced a small but very important steering and front wheel in the same direction can make up the oversteering trend, the balance of this will make cars better.

The vehicle in cornering, change the wheel touchdown area and wheel alignment will lead to changes in steering characteristics. It should be said that the rear wheel steering technology can make up for the inherent defects of the vehicle steering mechanism caused by the use of rubber pneumatic tires. The rear wheel steering is more like the working principle of the ESP system, namely, when the vehicle is moving at high speed, the stability of the vehicle is maintained by braking a certain or a certain number of wheels.

Rear wheel steering

This structure is very simple, it is not the layout of a complete set of steering mechanism in the rear, but only in the rear suspension, the rubber pad is arranged between the suspension and the body, through the rubber suspension and body flexible connection, because the rubber has certain elasticity, so when the vehicle is turning, the elastic deformation occurred can the rear suspension connection point of the rubber pad in the lateral force, so as to drive the wheels of change at a certain angle. The steering angle depends on the hardness of rubber cushion. The rubber pad is soft, the rear wheel steering angle is variable, but the suspension stiffness reduce poor stability, more hard rubber cushion, the rear wheel steering angle is small, but the suspension stiffness, high stability. Therefore, in the design need to weigh its advantages and disadvantages, according to the actual use of the focus of the car to adjust, in general, the steering angle of the rear wheels are below 3 degrees.