Simulation of Friction Fault of Lightly Loaded Flywheel Bearing Cage and Its Fault Characteristics

Abstract

Because of the operating environment and load, the main fault form of flywheel bearing is the friction fault between the cage and the rolling elements, which often lead to an increase in the friction torque of the bearing and even to the failure of the flywheel. However, due to the complex mechanism of the friction fault, the characteristic frequencies often used to indicate cage failure are not obvious, which makes it difficult to monitor and quantitatively judge such faults. Therefore, this paper studies the mechanism of the friction fault of the flywheel bearing cage and establishes its fault feature identification method. Firstly, the basic dynamic model of the bearing is established in this paper, and the friction between the cage and the rolling elements is simulated by the variable stiffness. The influence law of the bearing vibration response reveals the relationship between the periodic fluctuation of cage-rolling element friction failure and the bearing load. After analyzing the envelope spectrum of the vibration data, it was found that when a friction fault occurred between the cage and the rolling element, the rotation frequency component of the cage modulated the rotational frequency component of the rolling element, that is, the side frequency components appeared on both sides of the characteristic frequency of the rolling element (with the characteristic frequency of the cage as the interval). In addition, the modulation frequency components of the cage and rolling element changed with the severity of the fault. Then, a modulation sideband ratio method based on envelope spectrum was proposed to qualitatively diagnose the severity of the cage-rolling element friction faults. Finally, the effectiveness of the presented method was verified by experiments.

Study on Cage Wear of Railway Traction Motor Bearings Based on Analysis of Rolling Element Motion

“…Since there is no perfect way to reduce cage wear, several studies on cage wear have been conducted to date. There are various approaches to addressing cage wear, such as examining cage specifications [3], improving lubrication [4], developing wear detection techniques [5,6], and developing cageless bearings [7]. The problem of cage wear becomes even more apparent when the bearing is used under light loads in addition to high rotational speeds.…”

Intelligent Early Fault Diagnosis of Space Flywheel Rotor System

“…The operational accuracy of the flywheel could be reduced by various factors, such as the abnormal rubbing of cages [7], wear [8], or the surface damage defects [9] of bearings, which could further lead to the failure of the attitude control system. Given the complex types of early faults and the insufficient labeling data and missing fault types in flywheel rotor systems, the intelligent early fault diagnosis of space flywheel rotor systems becomes a challenging task.…”