u bolt for mechanical suspension and bogie use

In the actual assembly process of vehicle chassis suspension, the quality control of dynamic and static torque of front and rear U-bolts is particularly important. Because after the assembly of the cab components and other components of the vehicle, the torque of the U-bolt will be attenuated to a certain extent, and after the vehicle is tested on the road, the torque will be further attenuated, leading to the fracture of the central bolt of the leaf spring, the dislocation and fracture of the leaf spring, and the attenuation of the bolt tightening torque will have a greater impact on the stiffness and stress distribution of the leaf spring, which will lead to the failure The deformation of leaf spring is an important reason. Heavy truck suspension system components damaged. The main reasons are as follows:

1.Because the U-bolt of leaf spring does not have enough pre tightening force and gradually relaxes, the maximum stress is transferred from the U-bolt to the central bolt, and the maximum bending moment is also increased. When the vehicle is overloaded or affected by uneven road bumps, it will fracture, while when the vehicle is overloaded for a long time, most of it will fracture.

2.The U-bolt itself will not be tightened or loosened, resulting in the weakening of its effective torque, which will reduce the prestress of the leaf spring and weaken the stiffness of the leaf spring assembly. The uniformly distributed stress of the support seat changes into concentrated stress, which makes the center of the leaf spring empty to produce stress concentration.
Therefore, after driving for a period of time, truck drivers need to observe and inspect the U-bolts irregularly to see if there is any relaxation. If there is any relaxation, they need to be preloaded.