Influência do controle de temperatura em ensaios de deslizamento lubrificado de superfícies conformes

Abstract

The use of lubricating fluid acts directly in reducing friction and wear between animated solid surfaces of relative motion through partial or complete separation of surfaces. This idea is not new, since records dating back to ancient Egypt on the use of oilseed substances are found in order to reduce friction between the blocks of stones used in the construction of pyramids. The lubrication efficiency of an oil is influenced by its properties, such as its composition, consistency and surface activity. However, the fundamental factor for the study of lubricant performance and efficiency is the understanding of the characteristics of the tribological system. Temperature is directly related to the viscosity of the lubricating fluid, which influences the tribological behavior of lubricated systems. The present work aims to analyze the effect of lubricant fluid cooling on the performance of lubricated block-on-ring tests. To cool the fluid, the heating system of the lubricant fluid of the Tribometer Falex® block on ring has been adapted to function as a radiator, thus preventing the heating of the lubricating fluid. Lubricated sliding wear tests were performed on ABNT 1045 compliant steel samples with loads 49.05 N and 98.1 N, in the presence of the refrigeration system. It is important to highlight that the tests performed during the work have as main reference the mechanical systems that use hydrodynamic bearings. The present work showed that the cooling of the lubricating fluid reduced the coefficient of friction by 28.26% and 62.76% for the loads of 49.05 N and 98.1 N, respectively. Therefore, the temperature reduction resulted in a higher viscosity of the lubricating fluid, reducing the contact of sample and ring roughness.