An Empirical Investigation of the Impact of an Axially Oscillating Shaft on Friction and Lubrication in Cylindrical Roller Bearings

Titelangaben

Meinel, Andreas ; Tremmel, Stephan:
An Empirical Investigation of the Impact of an Axially Oscillating Shaft on Friction and Lubrication in Cylindrical Roller Bearings.
In: Bearing World Journal. Bd. 3 (2018) . - S. 41-55.
ISSN 2513-1753

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Abstract

Rolling element bearings experience dynamic axial thrust and oscillating shaft movements of various frequencies and amplitudes in a multitude of applications, especially in heavy-duty machinery. These operating conditions can cause significant friction losses which entails higher operating temperatures and lower lubricant operating viscosities. Dynamic axial shaft movements increase shearing between rollers and raceways excessively which impairs the mechanical stability of the lubricant. In consequence, this results in accelerated lubricant degradation and may cause insufficient lubrication or even premature bearing failure. In order to choose a suitable lubricant for such a bearing application that experiences axial shaft movements or to be able to adequately schedule lubricant maintenance intervals, the occurring shear- or friction forces between rollers and raceways due to the axial oscillations are of particular interest. Therefore, in an experimental study, an oil-lubricated cylindrical roller bearing NU210 has been subjected to dynamic axial shaft movements of various frequencies and amplitudes. Two specifically designed bearing test rigs are introduced within the scope of this paper and the experimental procedure is presented. The results obtained which include measurements of axial friction forces between rollers and raceways, steady-state operating temperatures, bearing friction losses as well as cage slippage are discussed in detail and an axial friction coefficient is derived from the results. Concluding, a short assessment is given, to what extend axial shaft movements might exhibit a critical impact on lubricant performance, friction and wear.