What is the role of a locknut in mechanical assemblies?

The role of a locknut in mechanical assemblies is primarily to secure a bolt or screw against loosening due to vibrations or rotational forces. When a locknut is tightened against a regular nut or a bolt's head, it creates a frictional resistance that prevents movement between the components. This is crucial in applications where vibration could lead to loosening, which might compromise the integrity of the assembly and lead to potential failures or hazards.

Locknuts are specifically designed with features such as serrations or nylon inserts that increase friction significantly compared to regular nuts, which is essential for maintaining a stable connection in dynamic environments. This function makes locknuts a common choice in machinery and structural applications where safety and reliability are paramount.

Other options like providing electrical insulation, acting as a spacer, or absorbing vibration address different functions unrelated to the primary purpose of a locknut in securing mechanical connections.