Session: 03-13-01: Manufacturing: General I

Paper Number: 166110

Effects of Lubricant Groove Design on the Steady State Performance of Hydrodynamic Tapered-Land Thrust Bearings 

Unlike rolling element bearings which are composed of an assembly of balls or rollers, a cage, and a raceway, hydrodynamic thrust bearings reduce friction and support loads using only the bearing surface and a thin film of lubricant. A common type of hydrodynamic thrust bearing is the tapered-land thrust bearing; they are typically composed of a central lubricant inlet hole, and sectors that have tapered and flat portions to stimulate pressurization of the lubricant film. A lubricant groove (or vein, typically machined) separates each sector and its primary function is to feed fresh lubricant into the tapered region of the sector during operation. The load supporting mechanism of hydrodynamic tapered-land thrust bearing begins with the converging motion between a rotating thrust collar and the bearing. As lubricant is being supplied into the inlet hole, it flows into the lubricant grooves where it is then squeezed (due to shearing) into the wedge-like region created by the tapered bearing section and converging flat thrust collar. The squeeze effect pressurizes the lubricant thus resisting axial loads and maintaining separation between the shaft and bearing. Although rarely studied, lubricant groove geometry plays an important role in the overall operation of the bearing, if too restrictive, the bearing may become starved. If the grooves are too large thus allowing excessive flow through the bearing and not forcing it to move into the wedged shaped region, then again, the bearing may become starved. Lubricant groove geometry varies between manufactures and is selected based on testing which is often not shared publicly. The primary groove geometries seen throughout industry include V-grooves, square-grooves, and rounded-grooves, however, experimental studies comparing these commonly used lubricant grooves on hydrodynamic tapered-land thrust bearings are not publicly available. The research presented here aims to experimentally investigate how machined lubricant groove geometry impacts the steady state performance of hydrodynamic tapered-land thrust bearings. Experimental analysis was conducted on an aluminum-based V-grooved, square-grooved, and rounded-grooved tapered-land thrust bearing, each having equal taper depths, sector counts, and diameters. Each bearing was subjected to applied loads and rotational speeds of 222.4 – 667.2 N and 1500 – 2000 RPM, respectively. Film pressure distribution, film thickness and bearing temperature was recorded for each test. Inlet pressure was also recorded during each test so analysis of flow restriction as it relates to the geometry of the lubricant grooves could also be conducted. The data obtained in this analysis provides experimental insight into the effects of lubricant groove design on the steady state performance of hydrodynamic tapered-land thrust bearings. Further, based on this work, manufacturing friendly groove geometries are recommended.

Presenting Author: Muhammad Ali Ohio University

Presenting Author Biography: Dr. Ali is a faculty in Mechanical Engineering Department

Authors:

Isaiah Yasko Ohio University
William Downs Ohio University
Ian Switzer Ohio University
Muhammad Ali Ohio University
Richard Walker Miba Bearings