Views:14 Author:Site Editor Publish Time: 2021-10-11 Origin:Site
Due to the large volume, semi-trailers are not suitable to move in a narrow space. However, they have to adjust the vehicle attitude in a narrow space under many working conditions. Thus, in order to solve this problem, the rear wheel steering system came into being. Through the reverse rotation of the rear wheel on the guide wheel, it reduces the turning radius of the vehicle and greatly improves the flexibility of the truck.
There are two main types of rear wheel steering: the rear wheel steering of tractor trailer and the rear wheel follow-up steering of integrated vehicle.
1. The rear wheel steering on the tractor is divided into follow-up and manual control. The following type automatically adjusts the steering angle of the rear wheel of the trailer according to the steering angle of the tractor head.
This adjustment is subdivided into two categories. One is widely used on military tractors. It uses hydraulic devices to independently adjust the steering angle of each wheel of the trailer. The adjusted angle is based on the program set in advance. This program will ensure that the wheels comply with Ackerman angle theory, that is, the normals of the steering angles of each wheel intersect at one point.
In this way, the wheels of the semi-trailer can be in a pure rolling state when turning. And it can avoid the phenomenon of "twisting the tire" of the ordinary semi-trailer when turning, which greatly reduces the wear of the tire and makes the vehicle attitude more stable. For the military card that often runs on the non paved road, it can also avoid the tire pushing away the soil and causing the vehicle to sink when turning.
In addition to this complex rear wheel steering system, there is a simpler structure. Two matched tooth bosses are designed between the rear wheel base and the axle fixing point. When turning, the trailer wheels squeeze and jack up each other because they receive transverse friction to realize steering. When driving in a straight line, the transverse force disappears and the rear wheel returns to normal independently.
The manual control type is mainly used on the large cargo transport vehicle. Its structure is similar to the hydraulic control type rear wheel steering system, but it is changed to manual control. When adjusting the angle, one person needs to cooperate with the driver at the rear of the vehicle. The adjustable angle is larger, and the axis plate steering structure used in the transportation of large cargo is also similar.
2. The rear wheel steering system of the integrated vehicle is all follow-up type, which greatly alleviates the problem of tire wear and greatly improves the flexibility.