Experimental and numerical study of the influence of loading direction on the lubrication and cooling of self-circulating oil bearing system applied in internal gear pumps

For middle-pressure and high pressure gear pumps, the temperature failure problem of bearings is now of considerable concern due to their heavy loads. A self-circulating oil bearing system has been developed for gear pumps in this paper to solve this problem. A test rig has been designed and built to carry out a series of tests for variable loading directions and rotational speeds. An experimental investigation and numerical model development to predict the behaviour of the self-circulating bearing subjected to different loading directions is described. The experimental and numerical results agree well. It was found that the variation of loading directions has a strong effect on the oil flow rates of the system. The maximum oil flow rate can be achieved when the loading direction is along the hole axis direction and a considerable part of the friction heat can be carried away by the oil. The lubrication of the bearing will also be improved.