Projeto e construção de um equipamento para teste de lubricidade de óleos lubrificantes minerais e sintéticos

Abstract

The study on lubrication works in several areas, for example, in the industry where each type of lubricant has its specification in order to generate savings, a greater gain in time of use and a reduction in wear failures. Each application requires an adequate study, a previous evaluation carried out under similar operating conditions, maintaining a guarantee range so that there is reliability and performance improvement. Thus, the objective is to design and build a test equipment to evaluate the lubricity of mineral and synthetic lubricating oils. The equipment applies the block-in-cylinder type of test, in which the specimens used are immersed in the fluid and made of 1020 drawn steel. The structure of the equipment consists of an electric motor of 0.7 hp and free rotation of 1100 ± 50 rpm transmitting its movement to a torque sensor that captures the influence that a given lubricating fluid makes on a forced contact within a period of up to 15 minutes per test. The data captured for each analysis are time (s) and torque (N.m) resulting from the applied load. The applied loads range from 1kg to 10kg. The volume of oil used in each test corresponds to approximately 5.0 ml. To evaluate the prototype equipment, two tests of 15 (fifteen) minutes were carried out with a load of 5.0 kg and with a rest time of 5 minutes using oil (A) mineral lubricant 20w50 and oil (B) synthetic lubricant 5w40 , so that the results were compared to the test results performing a standardized “Four ball” equipment with the same load parameters and test time. A micrograph test of the wear of both tests proved that oil (A) has greater lubricity than oil (B). The difference in precision between the Block in the cylinder test and the “Four Ball” was around 0.022 N.m for Oil A and 0.147 N.m for Oil B, showing that the prototype equipment is following the desired result. With this, the equipment is ready for use in which it is necessary to carry out more tests with other lubricating fluids and combine possibilities of working time and applied loads in order to create a database to serve as a comparison for future materials in research. The specimens used in each test can be taken for further analysis and the oil for the ferrography test.