The driving system is divided into four main parts: axle, wheel, frame and suspension

According to different driving methods , axles are also divided into steering axles , drive axles, steering axles and support axles. Steering and support bridges are driven bridges . Most cars use front-rear drive (FR), so the front axle acts as a steering axle and the rear axle acts as a drive axle; the front-front drive (FF) car, on the other hand, becomes the steering axle and the rear axle acts as a support bridge.

The structure of the steering axle is basically the same, consisting of two knuckles and a beam . If we compare the beam to the body, the knuckle is the head that he shakes around. The neck is the kingpin we often say. The wheels are mounted on the knuckles , as if there were a straw hat on the head. However, the straw hat turns when driving, but the head does not turn, the middle is separated by a bearing , the head just shakes around. Neck - The main pin is the axis of rotation of the wheel , the axis of this axis is not perpendicular to the ground, the wheel itself is not vertical, we will discuss in the wheel positioning section.

The difference between the steering axle and the steering axle is that everything is hollow, the beam becomes the axle housing , and the steering knuckle becomes the steering knuckle housing because there is more drive shaft inside . This driveshaft is split into two by a differential located in the middle of the axle housing and becomes two axle shafts . The two straw hats are not simply placed on the head, but are also directly connected with the two half shafts inside. The half shaft also has a joint in the "neck" position - the universal joint , so the half shaft also becomes two parts, the inner half shaft and the outer half shaft.