考虑局部故障边缘形态的球轴承振动特征

在分析球与不同边缘形态的局部故障之间接触关系的基础上,根据赫兹接触理论建立了球与局部故障光滑圆柱型边缘之间的接触刚度模型,以及球进入故障区域时的时变位移激励模型。考虑弹性流体动力润滑油膜的影响,提出时变冲击激励耦合的球轴承圆弧边缘型局部故障动力学模型。该模型考虑了故障边缘形态特征变化引起的球进入故障时的时变额外位移激励,以及球与故障边缘之间的时变接触刚度。研究滚道表面圆弧型边缘型局部故障激励下的球轴承振动响应特征,并分析故障边缘形态变化对球轴承振动响应特征的影响规律,解决了尖锐边缘型局部故障模型无法描述其边缘形态变化的问题,为获得可靠的局部故障球轴承的动力学响应特征提供新的手段和方法,也为球轴承局部故障的准确识别与定量诊断提供一定的理论依据。

An Investigation of Vibration Characteristics of a Ball Bearing with a Localized Defect Considering Different Edge Shapes

According to the contact relationship between the ball and localized defect with different shapes, a contact stiffness model for the ball-defect edge contact based on Hertzian contact theory is presented, as well as the time-varying displacement model in the defect zone. A new dynamic model coupling time-varying excitations for a lubricated ball bearing with a localized defect on its races is proposed considering the lubricating film oil. This model can formulate the time-varying excitations including the time-varying displacement excitation when the ball passing over the defect zone and the time-varying contact stiffness between the ball and the defect cylindrical edges. The proposed model is applied to investigate the effect of the defect edge shape on the vibration characteristics of the ball bearing. The numerical results show that the proposed model can describe the effect of the changes in the edge shape of the defect on the vibration characteristics of the ball bearing, which cannot be formulated by the previous sharp defect edge models in the literature. It seems that the proposed method can provide some new approach for predicting accurate vibration characteristics of the ball bearing with a localized defect on its races. It also can provide some theoretical foundations for accurate ball bearing fault defection and diagnosis.