볼 베어링의 구름 요소 주위 유동 특성에 대한 해석

Abstract

*Center for Bionic Systems Korea Institute of Science and Technology**Dept. of Mechanical Engineering, Graduate school, Yonsei University(Received August 1, 2012; Revised September 4, 2012; Accepted September 8, 2012)Abstract − Various bearings such as deep-groove ball bearings, angular-contact ball bearings, and roller bearingsare used to support the load and to lubricate between the shaft and the housing. The bearings of potential rollingsystems in a turbo pump are the deep-groove ball bearings as comparing with the bearings with rolling elementssuch as cylindrical rollers, tapered cylindrical rollers, and needle rollers. The deep-groove ball bearings consistof rolling elements, an inner raceway, an outer raceway and a retainer that maintain separation and help to lubri-cate the rolling element that is rotating in the raceways. In the case of water-lubricated ball bearings, however,fluid friction between the ball and raceways is affected by the entry direction of flow, rotation speed, and flowrate. In addition, this friction is the key factor affecting the bearing life cycles and reliability. In this paper, thecharacteristics of flow conditions corresponding to a deep-groove ball bearing are investigated numerically, withparticular focus on the friction distribution on the rolling element, in order to extend the analysis to the area thatexperiences solid friction. A simple analysis model of fluid flow inside the water-lubricated ball bearing is ana-lyzed with CFD, and the flow characteristics at high rotation speeds are presented. Keywords − ball bearing (볼 베어링), fluid flow characteristics (유체 흐름 특성), rolling element (구름 요소), shear stress (전단응력), torque (토크)