Experimental Investigation of Clearance Influences on Cage Motion and Wear in Ball Bearings

Baogang Wen,Jingyu Zhai,Xu Zhang,Meiling Wang,Wei Sun

doi:10.3390/app112411848

Baogang Wen, Jingyu Zhai + Show 3 more

Open Access

https://doi.org/10.3390/app112411848

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Abstract

Clearances of cages in ball bearings, including pocket and guiding clearances, play a vital role in the stability and reliability of bearings. In this paper, experiments on the cage motion and wear were carried out to investigate the influence of clearances in ball bearings. Firstly, the cages with a series of pocket and guiding clearances were specially designed and tested for prescribed operating conditions on a bearing test rig in which the cage motions were measured, and corresponding wear was also observed. Then, the normalized trajectory, waveform, and spectra of cage motion were constructed and compared to illustrate the effects of clearances on the cage motion and then to establish the relationship between cage motion and wear. Results reveal that the cage motion and wear are both significantly affected by its clearances. The increment of cage guiding clearance makes the whirl trajectories of the cage regular and the motion frequency of cage motion significantly change. However, the increment of cage pocket clearance make the whirl trajectories change from well-defined patterns to complicated ones, and the frequency of cage motion apparently changes. Additionally, the bearing wear is closely related to the cage motion. If the inner ring frequency is of domination for the cage motion, the cage guiding surface will wear seriously. While cage motion is dominated by two times cage frequency in spectrum domain, the cage pocket will wear more seriously.

Highlights

A cage is a key component in rolling bearings to ensure stable running [1]
The cage motion plays a decisive role in the dynamic performance and service life of the bearing, even leading to abnormal operation of the bearing and occasionally premature bearing failure [6,7]
Ghaisas [8] and Liu [9] discussed the effects of the ratio of pocket clearance to guiding clearance on the cage motion in a cylindrical roller bearing and ball bearing, respectively, and indicated that cage motion stability is strongly dependent on the roller-cage pocket clearance

Summary

Introduction

A cage is a key component in rolling bearings to ensure stable running [1]. The cage clearance is one of the important parameters influences on bearing properties, such as lubrication [2], oil film [3], and heating [4], and especially cage motion and instability [5]. Meeks [11] analyzed the cage motion and forces affected by varying cage clearances and found that if a bearing has a larger ball pocket clearance compared with the guiding clearance, this may result in cage nonsynchronous motion and lower ball forces. Ryu [13] experimentally investigated the cage instability with respect to ball-pocket clearances by measuring the friction coefficient of bearing and sound vibration and found larger ball-pocket clearance to be more stable. As for the cage motion measurements in rolling bearings, Gupta [15] checked a certain shaft speed at which the cage can run into a whirling pattern. A bearing test rig was specially developed to measure the spatial motions of the cage, and six diverse pocket and guiding clearances of the cage were designed and carried out on the test rig at prescriptive operating conditions. All the experimental results are useful references for cage ball-pocket clearance design and optimization

Experimental Approach

Description of Test Rig

TesNteudmBbeearroifnbgaallns d Cage Design

Radial Motions of the Bearing Cage

Wear of the Bearing Cage