The axle refers to the column on the vehicle that connects the two wheels to fix it on the vehicle to bear the weight of the vehicle body. Each pair of left and right wheels is connected by an axle. Of course, the axle semi trailer is much more complicated in structure, and is generally installed and used in the form of an axle assembly, which is what we often call an axle. The axle not only needs to bear the weight of the body, but also needs to bear the function of braking and maintaining the vehicle running, so its performance is particularly important for driving safety. Knowing what an axle is, then the wheelbase is easier to understand. The wheelbase of a semi-trailer refers to the distance from the center of the front axle to the center of the rear axle, the distance between two perpendicular lines passing through the centers of two adjacent wheels on the same side of the vehicle and perpendicular to the longitudinal symmetry plane of the vehicle.

Ⅰ. The wheelbase of the semi-trailer can be divided into fixed wheelbase, bogie wheelbase and full wheelbase

1. The fixed wheelbase refers to the horizontal distance between the centerlines of the front and rear axles in the main frame of the frame-type vehicle. In order to facilitate the passage of the curve, the fixed wheelbase should not be too long.

2. The wheelbase of a bogie refers to the distance between the centerlines of the axles at both ends of a bogie.

3. The full wheelbase of the semi-trailer axle refers to the horizontal distance between the centerlines of the front and rear axles of the vehicle, that is, the distance from the frontmost axle to the last axle, which is the main parameter affecting the "turntable length" of the train.

Ⅱ. For semi-trailers, the difference between the length of the wheelbase of the semi-trailer

1. Long wheelbase

(1) Advantages

The longer the wheelbase and the larger the turning radius, the more stable the vehicle travels; the longer the semi-trailer is, the more convenient it is to transport larger types of goods; the riding space can be expanded to a certain extent, and the comfort can generally be improved.

(2) Disadvantages

The longer the wheelbase of the semi-trailer, the less flexible the vehicle turns; although the riding space is comfortable, the handling is poor and the safety factor is reduced; the requirement for parking space is larger, and the long wheelbase means a larger parking space.

2. Short wheelbase

(1) Advantages

The wheelbase is short, the vehicle is more flexible, and it is more convenient to enter and exit the curve or park in the parking space; the short wheelbase has good movement and strong handling.

(2) Disadvantages

Poor stability at high speed; limited transport of goods.

As the most widely used model in the transportation industry, semi trailer air suspension plays a very important role, which requires that the quality of the axles used by semi-trailers must be strictly passed. Especially under the premise that the current lightweight trend prevails, the load-bearing performance of the axle itself must not be sacrificed blindly for the purpose of weight reduction, otherwise once the axle breaks during the full load process, the consequences will be disastrous. When car owners buy semi-trailer axles, especially lightweight axles, they must choose regular manufacturers, and must not believe in the publicity stunts of Sanwu products.