Effect of bearing thermally induced preload on the efficiency of automotive manual transmission under RDE

In order to calculate the efficiency of an automotive manual transmission, taking into consideration the effect of its most power consuming components – gears and bearings – as well as the interactions between them is of high importance. In this paper, a dynamic model has been developed which can predict the frictional losses of a complete gearbox as a system and, thus, its efficiency. The effect of temperature on bearing preload is also considered and taken into account from a system perspective identifying its effect on the bearings frictional losses (as well as the overall efficiency). The operating conditions used are snapshots of the Real Driving Emissions driving cycle, which is a standard metric for automotive manufacturers. Results show that doubling the temperature can lead to 120% increase of the bearing losses and up to 140% increase of the total transmission losses. The effect of the variation of operating conditions (velocity and torque) is also taken into account. The novelty of this paper lays in the development of a dynamic model which takes into account the performance of a complete gearbox under transient operating conditions, as well as the interaction among its main components and the ability to make changes on the influencing factors of transmission efficiency so that their effect on the complete gearbox efficiency can be tracked. This has not been yet reported in the relevant literature which mainly focuses on the influencing factors of transmission power loss and efficiency experimental measurements under various operating conditions for gear pairs instead of complete gearboxes.

[1]  J. Greenwood,et al.  The Contact of Two Nominally Flat Rough Surfaces , 1970 .

[2]  J. A. Greenwood,et al.  Thermal analysis of an Eyring fluid in elastohydrodynamic traction , 1980 .

[3]  H Rahnejat,et al.  An investigation of manual transmission drive rattle , 2010 .

[4]  David,et al.  Determining Power Losses in Helical Gear Mesh: Case Study , 2003 .

[5]  Uttara Kumar,et al.  Investigation of spindle bearing preload on dynamics and stability limit in milling , 2012 .

[6]  Bernd-Robert Höhn,et al.  Influence factors on gearbox power loss , 2011 .

[7]  M. Schmied,et al.  Comparison of 3D Surface Reconstruction Data from Certified Depth Standards Obtained by SEM and an Infinite Focus Measurement Machine (IFM) , 2006 .

[8]  Homer Rahnejat,et al.  Transient mixed non-Newtonian thermo-elastohydrodynamics of vehicle differential hypoid gears with starved partial counter-flow inlet boundary , 2014 .

[9]  K L Johnson,et al.  Regimes of Traction in Elastohydrodynamic Lubrication , 1986 .

[10]  Ramiro C. Martins,et al.  Gearbox power loss. Part I: Losses in rolling bearings , 2015 .

[11]  J. F. Rigal,et al.  Static Rolling Bearing Models in a C.A.D. Environment for the Study of Complex Mechanisms: Part I—Rolling Bearing Model , 1999 .

[12]  Jeffrey L. Stein,et al.  A State-Space Model for Monitoring Thermally Induced Preload in Anti-Friction Spindle Bearings of High-Speed Machine Tools , 1994 .

[13]  S. Theodossiades,et al.  Lightly loaded lubricated impacts: Idle gear rattle , 2007 .

[14]  Homer Rahnejat,et al.  Effect of teeth micro-geometrical form modification on contact kinematics and efficiency of high performance transmissions , 2017 .

[15]  Necdet Demirhan,et al.  Stress and Displacement Distributions on Cylindrical Roller Bearing Rings Using FEM , 2008 .

[16]  K. Johnson,et al.  Shear behaviour of elastohydrodynamic oil films at high rolling contact pressures , 1967 .

[17]  Hannes Allmaier,et al.  Investigating the efficiency of automotive manual gearboxes by experiment and simulation , 2014 .

[18]  Homer Rahnejat,et al.  Multiphysics Investigations on the Dynamics of Differential Hypoid Gears , 2014 .

[19]  Clemens Schlegel,et al.  Detailed Loss Modelling of Vehicle Gearboxes , 2009 .

[20]  Homer Rahnejat,et al.  Effect of cylinder deactivation on the tribo-dynamics and acoustic emission of overlay big end bearings , 2014 .

[21]  Christophe Changenet,et al.  Power loss predictions in geared transmissions using thermal networks-applications to a six-speed manual gearbox , 2006 .

[22]  T. A. Harris,et al.  Rolling Bearing Analysis , 1967 .

[23]  Michael M. Khonsari,et al.  Experimental testing and thermal analysis of ball bearings , 2013 .

[24]  Yung C. Shin,et al.  Dynamics of Machine Tool Spindle/Bearing Systems Under Thermal Growth , 1996, Dynamic Systems and Control.

[25]  P. A. McKeown,et al.  Reduction and compensation of thermal errors in machine tools , 1995 .

[26]  J. Börner,et al.  How to Minimize Power Losses in Transmissions, Axles and Steering Systems , 2012 .

[27]  Homer Rahnejat,et al.  Gear teeth impacts in hydrodynamic conjunctions promoting idle gear rattle , 2007 .

[28]  Michael M. Khonsari,et al.  On the Thermally Induced Failure of Rolling Element Bearings , 2016 .

[29]  S. Theodossiades,et al.  NON-LINEAR DYNAMICS OF GEAR-PAIR SYSTEMS WITH PERIODIC STIFFNESS AND BACKLASH , 2000 .

[30]  Christophe Changenet,et al.  Housing Influence on Churning Losses in Geared Transmissions , 2008 .

[31]  Ahmet Kahraman,et al.  Prediction of Mechanical Efficiency of Parallel-Axis Gear Pairs , 2007 .

[32]  J. F. Dunn,et al.  A theoretical analysis of the isothermal elastohydrodynamic lubrication of concentrated contacts. II. General case, with lubricant entrainment along either principal axis of the Hertzian contact ellipse or at some intermediate angle , 1985, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[33]  G. D. T. Carmichael,et al.  MEASUREMENT OF THERMALLY INDUCED PRELOADS IN BEARINGS , 1970 .

[34]  T. A. Harris.  The endurance of a thrust-loaded, double row radial cylindrical roller bearing , 1971 .

[35]  Ramiro C. Martins,et al.  Gearbox power loss. Part II: Friction losses in gears , 2015 .

[36]  Martin Andersson,et al.  Churning losses and efficiency in gearboxes , 2014 .

[37]  Ahmet Kahraman,et al.  Oil Churning Power Losses of a Gear Pair: Experiments and Model Validation , 2009 .

[38]  Fabrice Ville,et al.  Influence of Aerated Lubricants on Gear Churning Losses–An Engineering Model , 2011 .

[39]  D. C. Evans,et al.  The shear properties of Langmuir—Blodgett layers , 1982, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[40]  Pradeep K. Gupta,et al.  Dynamics of Rolling-Element Bearings—Part IV: Ball Bearing Results , 1979 .

[41]  Ahmet Kahraman,et al.  An Experimental Investigation of Spur Gear Efficiency , 2008 .

[42]  Simon C. Tung,et al.  Automotive tribology overview of current advances and challenges for the future , 2004 .

[43]  Bernd-Robert Höhn,et al.  Optimization of Gearbox Efficiency , 2009 .

[44]  Miguel De la Cruz,et al.  The influence of transient thermo-elastohydrodynamic conjunctions on automotive transmission rattle , 2011 .

[45]  Ramiro C. Martins,et al.  Power losses at low speed in a gearbox lubricated with wind turbine gear oils with special focus on churning losses , 2013 .