Determination of ball bearing impedances under steady-state operating conditions using a further developed rolling contact model with full lubrication

由于越来越多地使用变频器来控制变速驱动系统、电动机和发电机，因此由滚动轴承中的寄生轴承电流（涡流、凹坑、润滑剂氧化）引起的损坏数量正在增加。为了预测或防止可能的轴承损坏，电气驱动系统可以用等效电路图建模，将电机的相关主要部件视为电容和电阻等效变量。考虑到这一点，滚动轴承还充当电容器。它的电性能在很大程度上取决于润滑和摩擦条件。目前，摩擦学系统之间的相互作用和由此产生的定义的电气行为的描述是一项具有挑战性的任务，这是实现的机电模型的滚动接触的帮助下，电容使用校正因子和校正函数。为此，将在项目范围内进行实验和模拟研究，以改进滚动轴承的电气建模，从而实现更精确的驱动系统建模。在工作计划内，将分两组（建模和实验）和两个级别（单接触和滚动轴承级别）对主题区域进行研究。通过滚动接触的耦合机械和电气仿真以及对边界影响（或接触的入口和出口面积）的详细考虑来执行建模。使用阻抗和充电曲线测量的实验结果用于验证。同时，将使用电场调查确定已开发和现有电接触模型（和校正函数）的局限性和适用性。该项目的目的是开发一个改进的滚动轴承阻抗模型（最初）纯轴向加载球轴承在充分润滑条件下。经验证的阻抗模型将作为导出基于物理的电滚动轴承模型的基础，用于点接触的轴向/径向负载滚动轴承。调查的重点是通过计算和实验确定的滚动轴承中的电接触电容的操作条件的准确描述。混合摩擦条件和电老化过程或损坏机制的调查不是该项目的主题。

As a result of the increasing use of frequency converters to control variable speed drive systems, electric motors and generators, the number of damages caused by parasitic bearing currents (corrugation, cratering, lubricant oxidation) in rolling bearings is increasing. To predict or prevent possible bearing damage, electrical drive systems can be modelled with equivalent circuit diagrams, considering the relevant main components of the motor as capacitive and resistive equivalent variables. In this consideration, the rolling bearing also acts as a capacitor. Its electrical behaviour depends significantly on the lubrication and friction conditions. Currently, the description of the interaction between the tribological system and the resulting defined electrical behaviour is a challenging task, which is realized by electromechanical models of the rolling contact with the help of electrical capacitances using correction factors and correction functions. For this purpose, experimental and simulative investigations will be carried out within the scope of the project in order to improve the electrical modelling of the rolling bearing and thus enable the possibility of more accurate modelling of the drive system.The subject area will be investigated within the work program in two groups (modelling and experiment) and in two levels each (single contact and rolling bearing level). Modelling is performed by means of coupled mechanical and electrical simulation of the rolling contact and detailed consideration of the boundary influences (or the inlet and outlet area of the contact). Experimental results using impedance and charge curve measurements are used for validation. In parallel, limitations and applicability of the developed and existing electrical contact models (and correction functions) will be determined using the electrical field investigations. The aim of the project is to develop an improved rolling bearing impedance model for (initially) purely axially loaded ball bearings under full lubrication conditions. The validated impedance model is to serve as the basis for deriving a physically based electrical rolling bearing model for combined axial/radial loaded rolling bearings with point contact. The investigations focus on the exact description of the operating condition through the computational and experimental determination of the electrical contact capacitance in the rolling bearing. Investigations of the mixed friction condition and electrical aging processes or damage mechanisms are not the subject of the project.