Development Of The Test Rig For Testing Traction Behaviors Of Journal Bearing Lubricated By Greases Under Low Speed And Heavy Load And The Experiment Study

In recent years, as application and promotion of tribology in industrial and technological field, the friction torque study for journal bearings that applied in important industrys was being paid more and more attention. Many literature has reported methods which calculated the friction torque through theoretical analysis, but only got rough results. In order to obtain more practical and accurate data, more and more designs need to measure the friction torque of the journal bearing under different loads, temperatures, speeds and lubrication conditions to estimate its life and the work efficiency, avoid design flaws, and improve its working state, and to provide exact basis for designning high reliability, high efficiency, long life journal bearing. But because most of journal bearings bear radial loads, and because of structure limits, the acquisition of the traction force will be inevitable afected by radial load during the test, So it is very difficult to test journal bearing friction torque in this way. So far, most of experimental studies were aimed at rolling bearings supported axial loads. But for journal bearing mainly bears radial load, it is seldom to see the test device for measuring the friction torque accurately.In order to simulate actual working conditions and to control them in the laboratory, the test rig was designed for testing traction behaviors of journal bearings lubricated by greases. The test rig includes four parts of drive device, loading device, bearing components and test system. Its main mechanical characteristics are, The test rig is driven by a 400W planet gear reduction motor with a frequency converter , which can provide 0.1-0.4 m/s stepless speed. This test rig has a 3 series levels of loading device and the double convex circle surfaces contact with the sleeve to simulate journal bearing, which can produce a high Hertz stress on surfaces by less weights but same to the effection of the journal bearing under the hevey load. So the rig's size and weight are greatly reduced. Load is imposed on the journal bearing through a boll bearing at the loading system terminal. Because the friction coefficient of the boll bearing is one to two orders of magnitude smaller than that of the journal bearing, so its friction would be negligible,.Thus the problem that the radial load interferes with the traction signal collection is well solved. By electrical heating and temperature control directly to the test part, the accurate ambient temperature can be provided from room temperature to 235℃. The traction force produced by the shaft sliding relative to the sleeve is collected by a rigid force sensor which contacts with bearing sleeve, and the data are processed and displayed by the computer system.By the rig, the grease used in Caterpillar engineering vehicles was tested in simulating working conditions of their journal bearings. The results were pretty good. After data analysis, the traction behavior of the special grease was clear.The test rig system provides a reliable way to measure friction torques of journal bearings under the radial loads. It has important practical value for many engineering fields which use journal bearings.