EFFECTS OF LUBRICATING CONDITIONS ON THE FRICTION COEFFICIENT OF SINTERED JOURNAL BEARINGS UNDER ALTERNATED LOADING

In this study, the performance of porous bearing was investigated under different lubricants and lubricating conditions. In order to carry out experiments, sintered bronze-based journal bearings were used in the tests. They are manufactured by powder metallurgy (P/M) techniques. To determine the effects of lubricating conditions that were with oil supplement (OS) and without oil supplement on tribological characteristics of these bearings under alternated loading, some experiments were carried out using different lubricants. In the tests, pure base oil (SAE 20W50), a fully formulated commercial engine oil (SAE20W50) and lubricating oils added at a commercial additive concentration ratio of 3% were used. The surfaces of test bearings were examined using optical microscopy. Experimental results showed that the friction coefficient conducted with base oil presented higher value than those of fully formulated oil both with OS and without OS lubricating conditions. In addition, commercial additive at a ratio of 3% concentration reduced the average coefficient of friction.