THEORETICAL AND EXPERIMENTAL STUDIES ON SLIDING AT LOW SPEEDS WITH INTERMITTENCIES

Abstract

The guides of the machine tools, brakes, clutches there is the possibility of the intermittent movement of stick-slip. This opens in the case of frictional couples with sliding motion, due to the low sliding speeds. Intermittent slip introduces vibrational phenomena and influences the uniformity of movement and the state of the surface of the couples due to their use. In this respect, the concerns related to the study of this phenomenon represent an interest in the machine building industry. The paper aims to achieve an original theoretical model for calculating the static and kinetic friction coefficients and its experimental verification on a stick-slip stand. The proposed theoretical model establishes the calculation relations of the static and kinetic friction coefficient and the connection between them taking into account the surface processing method. The originality of the approach is that the model is considered friction between the conical penetrator (steel material) and a polymer material. In the literature, the stick-slip phenomenon is approached only in terms of the analysis of flat surfaces. The torques of said materials is frequently used on the parts of sliding machines where this phenomenon is possible. The paper highlights the influence of exploitation factors (load, speed), the processing of surfaces, and the quality of the lubricating liquid on the stick-slip phenomenon, for a friction coupling of polymeric material / metallic material.