Measurement method for radial force of interference fit and the force evolution mechanism of the interference contact surface

Abstract The interference fit pressure assembly manufacturing process of spindles has the advantages of simple implementation, high quality control, high efficiency, energy saving, and being pollution-free, and it is widely used in the industrial manufacturing field. The key components of the force feedback mechanism of electrohydraulic servo valves need to be obtained through press-fit assembly manufacturing. However, during the assembly process, the axial displacement cannot be precisely controlled due to changes in frictional forces during the pressing process. Currently, there is a lack of research on position control for interference fits in the relevant fields. Therefore, it is necessary to conduct in-depth research on the friction process of the interference fit pressure assembly to identify the influencing factors and laws of the frictional forces during pressure assembly. The study proposes a method for measuring the radial pressure on a closed cylindrical surface, which utilizes the Poisson’s ratio of the pressed component material to obtain the radial strain, and subsequently calculates the radial force directly using the material’s elastic modulus. We find that under the effect of the Poisson ratio of the material, the actual pressing force exceeds the static bonding force and a theoretical model is established to derive the calculation formula for the frictional force of the interference fit contact surface during the pressing process. This effectively guides the application of pressing force during the spray nozzle interference fit pressure assembly process and to some extent plays a positive role in reducing creep and improving displacement accuracy.