Gear rattle modelling and analysis for automotive manual transmissions

Abstract This paper describes a model for torsional vibration of automotive manual transmissions and its subsequent analysis. The model is developed for the purpose of analysis and prediction of gear rattles. Efforts have been made to include as many components of power train as possible and to study the rattle responses of all the speeds. Elements of the model include engine, clutch, flywheel, laden and unladen gears, and shafts. Numerical methods available in MATLAB for solving the ordinary differential equations are employed for the dynamic analysis. Results are presented to show the effectiveness of the modelling and analysis scheme. A software package has also been developed to build and analyse any power train model. The package was used to analyse the Daimler-Chrysler T350 transmission and the results are presented in the paper. It is shown that the gear rattle may exhibit three major modes of double-sided, single-sided or irregular impacts. A rattle index has been used to compare the rattle levels produced by different gear pairs. This could be very useful for the purpose of tuning the clutch for the best rattle noise reduction.

[1]  P. Velex,et al.  An Analytical Expression for the Time-Varying Contact Length in Perfect Cylindrical Gears: Some Possible Applications in Gear Dynamics , 1996 .

[2]  Yu Wang,et al.  Dynamics of unsymmetric piecewise-linear/non-linear systems using finite elements in time , 1995 .

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

[4]  R. J. Comparin,et al.  Non-linear frequency response characteristics of an impact pair , 1989 .

[5]  Y. Cai,et al.  The Linear Approximated Equation of Vibration of a Pair of Spur Gears (Theory and Experiment) , 1994 .

[6]  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 .

[7]  Ray Shaver.  Manual transmission clutch systems , 1997 .

[8]  Andrew Szadkowski,et al.  Mathematical Model and Computer Simulation of Idle Gear Rattle , 1991 .

[9]  Todd E. Rook,et al.  Dynamic analysis of a reverse-idler gear pair with concurrent clearances , 1995 .

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

[11]  Todd E. Rook,et al.  Computational Issues Associated with Gear Rattle Analysis , 1995 .

[12]  Paolo Mantegazza,et al.  DYNAMIC RESPONSE OF MECHANICAL SYSTEMS BY A WEAK HAMILTONIAN FORMULATION , 1985 .

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

[14]  A. Kahraman,et al.  Steady state forced response of a mechanical oscillator with combined parametric excitation and clearance type non-linearity , 1995 .

[15]  Oliver Johnson,et al.  Diagnosis and Objective Evaluation of Gear Rattle , 1991 .