Experimental Investigations on the Effect of Surface Pocket in a Powder-Lubricated Journal Bearing on Friction and Vibration

This paper presents an experimental study on the influence of surface pockets on the friction and vibration of powder-lubricated journal bearings. A pocket in the bearing bore surface modifies the pressure profile compared with a conventional bearing, resulting in improved performance parameters. In the present work, a test rig was designed and fabricated to carry out experiments with three types of bearings (conventional, bearing with elliptical pocket, and bearing with rectangular pocket). A fine powder of molybdenum disulfide was used as a lubricant. Tests were conducted for different shaft speeds and external loadings. It was found that pocketed bearings offer lower friction as compared with conventional bearing at all speeds and external loads. In comparison with conventional bearing, frictional torque was decreased by 2.0-8.1 % with elliptical pocket bearing and 4.5-9.3 % with rectangular pocket bearing. Pocketed bearings also reduced the vibration amplitude of the bearing housing compared with conventional bearing; the root mean square (rms) value of acceleration with elliptical pocket bearing was reduced in the range of 3.0-10.0 %, while rectangular pocket bearing improved it by 6.8-11.4 %.