Lightly loaded lubricated impacts: Idle gear rattle

Abstract Idle gear rattle is associated with the characteristic noise that unselected impacting gears radiate to the environment. It is induced by engine order vibration in the presence of backlash in the unengaged gear pairs, resulting in oscillatory response within their backlash range. A tribo-dynamic model of a front wheel drive manual transmission has been developed to study idle rattle, considering the hydrodynamic contact film reaction and flank friction. The model includes the torsional motions of the idle gears and the lateral motions of the supporting output shafts. The hydrodynamic lubricant film formed between the gear teeth under light impact loads behaves as a nonlinear spring-damper mechanism, whilst the inclusion of the shafts’ bearing compliances introduces additional nonlinear terms, which are modelled as piecewise linear functions. The aim of the paper is to extend the existing methodology reported by the authors on idle rattle investigations of geared lubricated systems, based on torsional vibrations only, by considering the system response, which is eventually transferred to the gearbox case through the bearings. These are preliminary results found, which conform closely to experimental measurements taken from a vehicle equipped with a manual transmission of the same type.

[1]  Charles E. Johnson,et al.  COMPONENT INERTIAL EFFECTS ON TRANSMISSION DESIGN , 1984 .

[2]  Stephen P. Timoshenko,et al.  Vibration problems in engineering , 1928 .

[3]  Tsutomu Fujimoto,et al.  An Improvement of the Prediction Method of the Idling Rattle in Manual Transmission - In the Case of the Manual Transmission with Backlash Eliminator - , 2001 .

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

[5]  Stephanos Theodossiades,et al.  ON GEARED ROTORDYNAMIC SYSTEMS WITH OIL JOURNAL BEARINGS , 2001 .

[6]  Toshimitsu Sakai,et al.  THEORETICAL AND EXPERIMENTAL ANALYSIS OF RATTLING NOISE OF AUTOMOTIVE GEARBOX , 1981 .

[7]  Norio Okino,et al.  Closure to “Discussion of ‘Fluid Lubrication Theory of Roller Bearing—Parts I and II’” (1962, ASME J. Basic Eng., 84, p. 180) , 1962 .

[8]  Rajendra Singh,et al.  Dynamic interactions between loaded and unloaded gear pairs under rattle conditions , 2001 .

[9]  K. Johnson,et al.  Fluid Film Damping of Rolling Contact Vibrations , 1975 .

[10]  Süreyya Nejat Dogan,et al.  Zur Minimierung der Losteilgeräusche von Fahrzeuggetrieben , 2001 .

[11]  Rajendra Singh,et al.  Analysis of automotive neutral grear rattle , 1989 .

[12]  Michael Yu Wang,et al.  Numerical Modelling and Analysis of Automotive Transmission Rattle , 2002 .

[13]  Homer Rahnejat,et al.  The Tribo-Contact Dynamics Phenomenon in Torsional Impact of Loose Gears - Promoting Gear Rattle , 2002 .

[14]  H. Rahnejat,et al.  Vibration response of wavy surfaced disc in elastohydrodynamic rolling contact , 1990 .

[15]  Todd E. Rook,et al.  Modeling of Automotive Gear Rattle Phenomenon: State of the Art , 1995 .

[16]  Gisbert Lechner,et al.  Maß;nahmen zur Verringerung von Losteilschwingungen in Fahrzeuggetrieben , 1998 .

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

[18]  Ramsey Gohar.  Experimental Methods in Elastohydrodynamics , 2001 .

[19]  Pietro Bellomo,et al.  Innovative Vehicle Powertrain Systems Engineering: Beating the Noisy Offenders in Vehicle Transmissions , 2000 .

[20]  Y. Cai,et al.  Simulation on the Rotational Vibration of Helical Gears in Consideration of the Tooth Separation Phenomenon (A New Stiffness Function of Helical Involute Tooth Pair) , 1995 .

[21]  Kiyohiko Umezawa,et al.  VIBRATION OF POWER TRANSMISSION HELICAL GEARS (APPROXIMATE EQUATION OF TOOTH STIFFNESS) , 1986 .

[22]  Kiyohiko Umezawa,et al.  Analysis Method for the Contribution Rate of Each Pair of Gears on the Driveline Gear Rattle , 1996 .

[23]  Rajendra Singh,et al.  A new gear mesh interface dynamic model to predict multi-dimensional force coupling and excitation , 1995 .

[24]  Homer Rahnejat,et al.  The Vibrations of Radial Ball Bearings , 1985 .

[25]  Riccardo Russo,et al.  A gear rattle model accounting for oil squeeze between the meshing gear teeth , 2005 .

[26]  Norio Okino,et al.  Fluid Lubrication Theory of Roller Bearing—Part II: Fluid Lubrication Theory Applied to Roller Bearing , 1962 .

[27]  Shan Shih,et al.  Drivetrain Noise and Vibration Troubleshooting , 2001 .

[28]  Stefan Dutre,et al.  Prediction of system-level gear rattle using multibody and vibro-acoustic techniques , 2004 .

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

[30]  R Manoj,et al.  Gear rattle modelling and analysis for automotive manual transmissions , 2001 .

[31]  Rajendra Singh,et al.  Interactions between time-varying mesh stiffness and clearance non-linearities in a geared system , 1991 .