How much do you know about trailer balance beams and shaft pins?

What are balance beams and pivot pins

Conventional trailer suspension structures are mostly seen in leaf springs, airbag suspensions and a rare rubber suspension. In terms of economy and load capacity, leaf spring suspensions are of course more advantageous, and balance beams and pivot pins are exactly leaf springs. As part of the suspension structure, let me introduce their functions and damage symptoms separately.

(1) Balance beam: The balance beam of the trailer is located in the middle of the front and rear two sets of leaf springs. Its working principle is like a "seesaw". As the fixed point of the steel plate floating frame, it also plays a role in balancing the bearing capacity between the axles. , so that when the vehicle is driving on undulating roads, the force on each axle is more even.

Generally, the balance beam is not easy to be damaged. Many of them are caused by the heavy load, which causes the steel plate floating frame and the top of the balance beam to wear too much, and all the force is applied to the shaft pin, which is like a "traction pin". "The role is the same, the steel plate bracket and the balance beam are combined together.

Common balance beam damage occurs on heavy-duty vehicles, and cracks appear directly on the top of the balance beam. After all, this is a fixed part of the chassis structure, and it has been welded when the trailer leaves the factory. If it is a standard For the loaded model, it is almost free of replacement for life, as long as the shaft pin and bearing hole are welded and replaced.

(2) Shaft pin: In fact, from a structural point of view, the shaft pin and the balance beam should be integrated. The reason why they are introduced separately here is precisely because attention needs to be paid when replacing the balance beam. If the balance beam is not worn by the base It is too serious, and the bearing hole cannot be repaired by welding. It only needs to replace the shaft pin, and its appearance looks like a circular shaft.

During work, the shaft pins are used to combine and limit the activity range of the balance beam and the steel plate floating frame. Even if it is a cylinder, I believe everyone has heard the saying, "As long as the hard work is deep, the iron pestle can be ground into a needle", and it will not last for a long time. During maintenance and replacement, the shaft pin will also lose its roundness due to wear and tear, thus losing the role of balance.