Commonly used anti-loose measures

Through the force analysis of the connected parts, determine the load mode it receives, such as the influence of axial load, lateral load, etc., and select the appropriate anti-loose method.

Increase the friction torque of the thread pair

In most existing product structures, there are many thread pairs that bear lateral loads. The anti-loosening method of increasing the friction torque of the thread pairs is the most widely used. For example, the fixing bolt of the front spring bracket of an automobile is subjected to a lateral load during actual work. effect.

The results of “Tightening Torque and Clamping Force Experiments” on hexagonal flange toothed bolts and hexagonal head bolts with the same nominal diameter by the Shanghai Zwick Laboratory prove that increasing the radius and surface roughness of the thread pair support surface The friction torque, when the lateral load is less than the friction, the thread pair will not loosen.

Improve the grade strength of bolts

When controlled by factors such as the shape, structure and cost of the connecting piece, the pre-tightening force of the bolt pair cannot meet the design requirements. You can choose to increase the grade strength of the thread pair and increase the pre-tightening force of the thread pair. Avoid that the required pre-tightening force is greater than the yield limit of the bolt, causing plastic deformation of the bolt to loosen.

Mechanical anti-loosening

This type of anti-loosening method uses various metal stop elements to prevent relative movement between the nut and bolt. Commonly used mechanical anti-loosening methods include split pins and hexagon nuts, stop washers, and tandem steel wires. This kind of anti-loosening method is suitable for occasions with large vibration, impact, and high speed, especially the occasions where the inside of the machine is not easy to inspect. The anti-loose method is reliable, but it is not easy to disassemble.

Anti-loosening of vice relations

This is a permanent way. The purpose of preventing loosening is achieved by destroying the thread pair. Commonly used methods to prevent loosening of the damage movement pair relationship include riveting, punching, brazing, etc. This method is reliable for preventing loosening, but cannot be reused.