AMESim Transmission Rattle Modeling

1. CAViDS Consortium AMESim Transmission Rattle Modeling A CAViDS Consortium Project Report to Eaton May 10, 2012

2. CAViDS Consortium Interim Project Objective • Model the effect of reverse synchronizer location on rattle intensity (tooth impact loading) on the FSO-2105A and compare with Isuzu • Set up the proper reverse gear set rattle model with driving gear and driven gears according to synchronizer location. • Model proper drag, pitch radius, and gear inertia for each gear in system • Model proper torsional vibration input to driving gear for equivalent comparison • Vary inertia of idler and amplitude of tooth impact loading

3. CAViDS Consortium FSO-2105A Synchronizer on Countershaft • 3rd gear operating ratio (1.47) at 1423 rpm input • Mainshaft reverse gear is driving gear • Reverse idler and reverse CS are unloaded • Torsional vibration on mainshaft is 300 rad/sec^2 • MS reverse gear inertia is 0.002953 kg-m^2 • Rev idler gear inertia is 0.0025 kg-m^2 • Backlash is 0.11 mm between each gear • Varied idler inertia from baseline to 0.0002 kg-m^2 • Varied torsional input from baseline to 2000 rad/sec^2

4. CAViDS Consortium AMESim Model

5. CAViDS Consortium Results Effect of Idler Inertia

6. CAViDS Consortium Results Effect of Torsional Input

7. CAViDS Consortium FSO-2105A Synchronizer on Mainshaft • 3rd gear operating ratio (1.47) at 1423 rpm input • Countershaft reverse gear is driving gear • Reverse idler and reverse MS are unloaded • Torsional vibration on countershaft is 310.3 rad/sec^2 • MS reverse gear inertia is 0.002953 kg-m^2 • Rev idler gear inertia is 0.0025 kg-m^2 • Backlash is 0.11 mm between each gear • Varied idler inertia from baseline to 0.0002 kg-m^2 • Varied torsional input from baseline to 2000 rad/sec^2

8. CAViDS Consortium AMESim Model

9. CAViDS Consortium Results Effect of Idler Inertia

10. CAViDS Consortium Results Effect of Torsional Input

11. CAViDS Consortium Conclusions Effect of Synchro Location • Effect of reverse idler inertia is significant in both synchronizer locations • Effect of torsional vibration is significant in both synchronizer locations • Synchro location does not seem to improve the rms level of rattle at high torsional input and normal idler inertias • With the synchro on the countershaft, as the reverse idler gear got smaller the character of the rattle was more single sided impact, because the both free gears were small inertia, had relatively high rattle thresholds, and inherently lower impact load (due to inertia).

12. CAViDS Consortium Isuzu Synchronizer on Mainshaft • 3rd gear FSO-2015 operating ratio (1.47) at 1423 rpm input • Countershaft reverse gear is driving gear • Reverse idler and reverse MS are unloaded • Torsional vibration on countershaft is 310.3 rad/sec^2 • MS reverse gear inertia is 0.002627 kg-m^2 • Rev idler gear inertia is 0.001 kg-m^2 (about 40% of the FSO-2105A) • Backlash was assumed to be 0.11 mm between each gear • Varied torsional input from baseline to 2000 rad/sec^2

13. CAViDS Consortium Results Effect of Torsional Input

14. CAViDS Consortium Isuzu Conclusions • The predicted reverse set rattle level (rms tooth impact load) at comparable torsional vibration inputs with the Isuzu transmission was about 85% of that with the FSO-2105A using the AMESim model described. • The Isuzu had about 80% of the peak torsional vibration at its output compared to the FSO-2105A according to the GM data (1200 rad/sec^2 vs 1500 rad/sec^2) • The combined effects of should have had the Isuzu reverse set rattle level at about 70% of the FS0-2105A. • The threshold of rattle perception on this vehicle is unknown, therefore evaluating the impact of the objectively predicted rattle on subjective reaction is very difficult. • The reason for the lower vibration level at the Isuzu transmission should be understood through modeling of the GM vehicle driveline.