What are the four types of frames according to their different institutional forms?

1, trapezoidal frame

It consists of two longitudinal beams and several cross beams. The cross-sectional shape of the longitudinal beam is groove-shaped, Z-shaped or box-shaped. The longitudinal beam can be curved, with equal cross-section or variable cross-section in the horizontal or longitudinal plane.

Trapezoidal frame is widely used in commercial vehicles and some buses because of its high bending strength and convenient installation of parts. It is rarely used in passenger cars.

2. Backbone frame

There is only one longitudinal beam in the center of the spine frame, which runs through the front and rear of the car. The cross-sectional shape of the longitudinal beam can be a circular tube or a box.

The frame of the spine frame is light in weight, high in strength and rigidity, and the spine frame with independent suspension can improve the passing capacity of the car. The disadvantages of the frame are high manufacturing accuracy and difficult maintenance.

3. Peripheral frame

The middle part of the frame is widened without beams, and its main part is often a closed section.

Because of its advantages of low floor height, large passenger room volume, simple structure, light weight and easy manufacture, the enclosure has been applied to large-displacement buses.

4. Truss

Trusses are welded by steel pipes. It has the characteristics of high rigidity and low mass, but it is difficult to manufacture, and is mainly used for racing cars.

Extended data

Most modern cars have a frame as the skeleton of the whole car. Most parts of the car are fixed by the frame, such as engine, transmission system, suspension, steering system, cab, cargo box and related control mechanisms. The frame plays the role of supporting and connecting all parts of the car and bears various loads from inside and outside the car.

The structural form of the frame must first meet the requirements of the general layout of the car. There should be no interference between the assembly and parts fixed on the frame during the complicated driving of the car. When a car runs on a rough road, the frame may be distorted in the longitudinal plane under the load.

When a wheel meets an obstacle, it may also twist the whole frame into a diamond. These deformations will change the relative position of the components installed on the rack, thus affecting its normal work. Therefore, the frame should also have sufficient strength and appropriate stiffness. In order to improve the lightweight level of the whole vehicle, it is required that the weight of the frame be as small as possible.

In addition, the frame should be arranged closer to the ground to reduce the center of gravity of the car and improve the driving stability of the car. This is especially important for buses and cars.