The automobile chassis is one of the important components of the automobile and the basis of automobile assembly. Its function is to receive the power of the engine to make the car move and ensure that the car can drive normally according to the driver's manipulation.

2. Structural composition of automobile chassis

The automobile chassis generally consists of four major systems: the transmission system, the driving system, the steering system, and the braking system.

3． Car chassis drive form

The driving form of the automobile chassis is related to the relative positions of the engine and the drive axle. Generally, there are the following four driving forms.

(1) Front-rear drive of the engine

Front-wheel drive of the engine, referred to as front-wheel drive (FR for short).

This is a traditional arrangement, which is widely used in various large and medium-sized cargo cars, mini cars and some premium cars. It is characterized by the need for a longer drive shaft, which increases the vehicle weight. Affects the efficiency of the drive system.

(2) Front-engine front-wheel drive

Engine front front wheel drive

Referred to as the front precursor (FF for short). This arrangement eliminates the universal joint and the drive shaft between the transmission and the drive axle, making the structure simple and compact. Because the front wheels are driving wheels, it helps to improve the stability of the car's handling at high speeds. According to the direction of the engine arrangement, it can be divided into engine front transverse front wheel drive and engine front longitudinal front wheel drive. This type of arrangement is currently widely used in cars and mini cars, but this type of arrangement has poor climbing performance. Luxury cars are generally not used, but instead use the traditional "front-drive" form.

(3) Rear-engine rear-wheel drive

The engine rear-mounted rear-wheel drive is referred to as rear-mounted rear-wheel drive (RR). This type of arrangement is to install the engine at the rear of the car. The engine has poor cooling conditions, and the operating mechanisms of the engine, clutch, and transmission are more complex. In the past, there are also a small number of cars and mini cars using this method.

(4) Front all-wheel drive of the engine

Engine front all-wheel drive, referred to as front all-wheel drive (nWD). nWD is the abbreviation of n Wheel Drive (n stands for the number of driving wheels), which indicates the form of all-wheel drive. It can be seen from Figure 1-5 that it is in the form of 4WD. A transfer case is provided behind the transmission, which distributes the power output by the transmission to the front and rear drive axles. The front drive axle can be switched on by a shift fork as required Or disconnected. This arrangement makes all wheels drive wheels, which greatly improves the off-road performance of the car and is widely used in off-road cars, special cars and military cars.