Energy Efficient Hydrodynamic Journal Bearings by Means of Closed-Loop Controlled Lubrication Flow

Abstract

State of the art of hydrodynamic journal bearing lubrication is realized by a significant oversupply with lubricant, causing energy losses due to fluid film friction in the unloaded areas of the bearing. Reducing the lubricant flow however may lead to overheating or collapse of the load carrying fluid film, both resulting in a complete failure of the journal bearing. A new approach to safely reduce the lubricant flow is presented in this paper, by using a broadband piezoelectric acoustic emission sensor to detect ultrasonic structure-borne noise, usually caused by metal-to-metal contact at boundary conditions. The method of structure-borne noise analysis has proven to be suitable for detecting the occurrence of solid friction [1–4]. By combining structure-borne noise analysis with a closed loop control of a proportional flow control valve a condition dependent lubricant flow can be set. Thus lubricant friction in the bearing is reduced and additionally electrical energy in the peripheral devices, such as pumps can be saved.

Actively lubricated hybrid journal bearings based on magnetic fluids for high-precision spindles of machine tools

“…Working with oil lubricated bearings, different approaches can be found in bibliography for pure hydrodynamic cases, e.g. closed loop control in oil feeding (Albers et al, 2011) to improve the energy efficiency of guiding, and in the particular case of tilting pads hydrodynamic bearings (Deckler, 2004;Nicoletti and Santos, 2003;Sun and Krodkiewski, 1999), the lubrication conditions and tilting angle of pads were modified by hydraulic or electromechanical actuators.…”

“…This solution has been explored with active air bearings by including flexible structures driven by piezo actuators (Aguirre et al, 2010;Morosi and Santos, 2011;Shamoto et al, 2006), but they are not transposable to high-pressure hybrid journal bearings. Working with oil lubricated bearings, different approaches can be found in bibliography for pure hydrodynamic cases, for example, closed loop control in oil feeding (Albers et al, 2011) to improve the energy efficiency of guiding, and in the particular case of tilting pads hydrodynamic bearings (Deckler et al, 2004;Nicoletti and Santos, 2003;Sun and Krodkiewski, 1999), the lubrication Regarding active bearings with hydrostatic lubrication, therefore with active restrictors (Jordan, 2000), some other research works aimed at (1) the improvement of hybrid bearings with servo-valves (Santos and Watanabe, 2006), (2) the study of active lubrication in complex multibody simulation (Estupin˜an and Santos, 2009) and (3) special considerations required for flexible rotors typical of energy generation machinery (Nicoletti and Santos, 2008). But a common characteristic in all those works was the use of either complex mechanisms for the bearing or precise servo-valves for lubricant feeding.…”