Lubrication life of cylindrical roller bearings for traction motors of railway vehicles (Effects of bearing temperature, vibration acceleration, and grease mass)

Abstract

In general, the life of a rolling bearing is calculated as the total number of rotations until rolling fatigue occurs on the raceway. However, when rolling bearings are used under light loads and high rotational speeds, they are damaged not by rolling fatigue on the raceways but by cage wear due to lubrication life. In such cases, the conventional method for calculating the rolling bearing life is not applicable. Rolling bearings for traction motors of railway vehicles (hereafter referred to as traction motor bearings) are one example of this and are replaced primarily due to lubrication life. However, there is no practical way to calculate lubrication life and these rolling bearings are replaced empirically. The purpose of this paper is to obtain basic data to create a method for calculating lubrication life. Therefore, traction motor bearings were rotated under conditions like actual operating conditions to reproduce damage due to lubrication life. As a result, damage due to lubrication life could be reproduced, so the next step was to investigate the effect on lubrication life when the operating conditions of traction motor bearings were varied as parameters. The parameters considered were “bearing temperature”, “vibration acceleration”, and “grease mass”. As a result of these verifications, lubrication life decreased exponentially when the bearing temperature was increased. In addition, lubrication life decreased exponentially when vibration acceleration was increased. Furthermore, lubrication life increased logarithmically when the grease mass was increased. The effects of these verified parameters on lubrication life could all be formulated within this paper.

Keywords

• railway
• traction motor
• cylindrical roller bearing
• lubrication life
• cage wear
• bearing temperature
• vibration
• grease mass