Diagnostics – Experimental Analysis of Friction Pairs at Stick – Slip Sliding

Abstract

The movement of parts of friction pairs with small quantities and displacements is the cause of the so-called stick-slip movement. This is due to the instability of the process of formation and destruction of adhesive contact between the surfaces. In this case, the lubricant has a decisive influence on the processes of friction in the contact. In this work, based on the diagnostic and experimental complex, the dependences of the magnitude of the friction force on displacements for various lubricants were obtained. Statistical characteristics of the scattering parameters of friction force are obtained to estimate the vibrations of a moving body. It is received that the dispersion of the friction force relative to the average value decreases with increasing load and with dry and lubricated contact. On the basis of the obtained experimental results, it is possible to establish some quantitative characteristics of such a movement: the number of oscillations (jumps) per unit of time; the average movement in a contact before a shift in a contact; the average resistance force in a contact before a shift. The correct selection of lubricant and loads ensures minimum values of vibrations of the friction units of machines. This consequently improves the positioning accuracy of the machines.