Trailer axle is a common supporting axle, also known as a follow-up axle, which generally does not have driving and steering functions. It mainly provides load-bearing, braking, and maintenance functions, and is a key component related to the vehicle's load-bearing capacity.

The axle, also known as the "axle assembly", refers to the welding of brake base plates, spherical bearing seats, air chamber brackets, etc. on the basis of the axle to form the axle assembly, and then the installation of camshaft assembly, brake assembly, wheel end assembly, cotter pins, adjustment arms and other components.

During installation, both ends of the axle are connected to the wheels through wheel end assemblies, and the middle is connected to the frame through a suspension system. Above the frame is the loading position for the goods. Therefore, the performance of the axle in the middle of the axle, commonly known as the "bridge rod" and "axle beam", directly determines the load-bearing capacity of the axle.

Common axles can be divided into two types: square tube and circular tube, which is better? What are the differences between a trailer square bridge and a circular bridge?

Traditionally, a circular shaft is one of the most common shaft shapes, consisting of a cylinder with different diameters and lengths;

The square axis has four planes and is usually composed of square columns. In the production process, there is an additional round to square process compared to the circular axis.

As for which of these two is better, generally under the same conditions, the bending and torsional resistance of the square axis is stronger. Due to the design of four right angles, the moment of inertia and center moment of the square axis are greater than those of the circular axis, making it less prone to deformation. For example, a circular tube with a wall thickness of 1cm may not be able to withstand a pressure of 50kg, and surface depressions are prone to occur in the middle; If two steel plates with a wall thickness of 1cm are welded vertically at 90 °, it may not be a problem to bear a pressure of 50kg, or even 100kg. This is the load-bearing performance of a right angle structure. So when the thickness of the axle wall is the same, the load-bearing capacity of the square tube is relatively stronger.

Of course, there is no question of 'which is better' for square and circular shafts, as long as they are used in the right working conditions. Although the bending resistance of circular pipes is not as good as that of square pipes in specific directions, their load-bearing performance in all directions is relatively balanced, and their advantages are more obvious in dealing with stress in all directions; Under the same cross-sectional area, the circumference of a circular tube is smaller than that of a square tube, so it uses less materials and has an advantage in self weight. In addition, on some special heavy-duty special axle types, such as low flat axle, three line six axle axle axle, etc., due to their high wall thickness and low center of gravity, they are also more suitable for using circular tubes.