Thermal Model of a Ball Bearing using the State-Space approach and Light Gray-Box Lumped Parameter Thermal Network

In this paper, a thermal model of a ball bearing subjected to radial loads is presented. By the application of the State-Space approach and the Light Gray-Box lumped parameter thermal network, the temperature of the inner components of a ball bearing, these are: outer-race To; balls Tb and inner-race Ti; and the temperature of the housing Th were determined. The relation between the external force, rotational speed, lubrication type, were investigated for the purpose of determining the total frictional moment Mf that occurs among the elements comprising the ball bearing. Subsequently, the total heat losses Qf were calculated together with the heat distribution along the elements of the ball bearing. The analytical results were validated experimentally. It could be seen that the standard deviation of temperature between the thermal model and the experimental measurements over the outer-race To and housing Th were sd = 5.06 % and sd = 0.33 % . Moreover, the temperature of the balls Tb and the inner-race Ti were predicted. In this context, the results show good agreement with real data, therefore, the thermal model can be utilized to foresee the thermal behavior of bearings with similar geometry that undergo effects of radial loads.