关键词: 滚动轴承, 局部故障, 时变激励, 撞击力, 动力学模型

Abstract: Establishing a dynamic model of rolling bearing local fault is a common method to study the mechanism of rolling bearing fault. There are complex contact processes when rolling elements pass through the fault area. The accuracy of the local fault excitation function directly affects the accuracy of the entire dynamic model. However, because local fault excitation is related to the bearing fault size, bearing speed and other conditions, the existing single simplified excitation function cannot accurately reflect the actual contact between the rolling element and the fault. Therefore, this article investigates the bearing outer ring fault. First, the change of contact gap of the rolling element passing through the fault area is analyzed, and the time-varying displacement excitation function related to the relative position of rolling element is established. Then, according to the impact force generated by the contact between the rolling element and the fault edge, an instantaneous impact force excitation function that takes into account the size of the fault and bearing speed is proposed. Under the guidance of the rigid ring hypothesis and Hertz contact theory, a dynamic model for the local fault of cylindrical roller bearing outer ring is established based on the above excitation function. The accuracy of the model is verified by the measured signal. Finally, the model is used to analyze the influence of fault size on vibration characteristics of one-and multi-dimensional bearings, thereby providing some guidance for state evaluation of rolling bearings in practical application.

Key words: rolling bearing, local fault, time-varying excitation, impact force, dynamic model