Experimental study of heat transfer between the rings of a roller bearing: influence of rotational speed and load

The heat transfer between the rings of a bearing are governed by two modes of transport related respectively to the two periodical movements of the rolling element. First is related to the orbital movement of the roller around the shaft; that is the orbital transport mode. The second mode is related to the rotational movement of the roller around its own axis in the double contact zone: it is the mode of transport by simple rotation. We model this heat transfer between the rings (solid convection) by a Transport Thermal Conductance (TTC) related to the raceway of external ring. The reference temperature is the one of the internal ring. The study of the influence rotational speed on the TTC emphasised that for the weak loads, the heat transfer by orbital transport increases quickly in the range 100-400 rpm. Under the influence of the centrifugal force, orbital transport becomes sufficiently significant to restrict the cooling of the external ring in double contact zone. This increase is braked when the speed corresponding to a permanent contact between rollers and the external ring is reached (430 rpm approximately). Beyond this speed, both transport modes are stimulated by the same mechanism: the reduction in thermal constriction resistances present on both sides of the rolling contact by the increase in speed. At low speed, the influence of the load is felt only in the double contact zone. For loads larger than 1000 N and speeds higher than 500 rpm, the two modes of transport become strongly Coupled and the TTC is then monotonous increasing according to the two parameters. (C) 2001 Editions scientifiques et medicales Elsevier SAS.