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CAViDS Consortium. AMESim Transmission Rattle Modeling. A CAViDS Consortium Project. Report to Eaton April 6, 2012. CAViDS Consortium. 2012 Project Objective. Develop AMESim Transmission Idle Rattle Model Use measured flywheel torsional input
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CAViDS Consortium AMESim Transmission Rattle Modeling A CAViDS Consortium Project Report to Eaton April 6, 2012
CAViDS Consortium 2012 Project Objective • Develop AMESim Transmission Idle Rattle Model • Use measured flywheel torsional input • Include appropriate clutch and transmission stiffness, mass and damping from specified medium duty transmission • Include backlash from splines and gears • Use verified predictions of bearing, synchronizer and churning drag • Use literature search and previous Eaton modeling efforts to guide development
CAViDS Consortium Work Plan Investigate basic AMESim rattle model capability Perform literature search Review previous Eaton models Input parameters from selected transmission Vary clutch pre-damper, backlash, and drag to determine effects Establish preliminary severity rating criteria
CAViDS Consortium 2012 Technical Status Built simple model in AMESim Verified basic dynamic effects Documented previous Eaton models Performed literature search Wrote preliminary report with recommendations Developed second level model
CAViDS Consortium Eaton Models Supercharger 2005 MATLAB Heavy Trans 2002 MATLAB Medium Trans 2007 Dymola
CAViDS Consortium Literature Search 25 papers Idle rattle and operating rattle Basic mechanism well understood Non linear behavior needs further study Rattle criteria developed Subjective/objective correlation established Conclusions Engine/driveline dynamic speed variation is forcing function When dynamic inertial torque on gears exceed drag, they separate and rattle Predamper spring can be used to isolate engine oscillations for idle rattle Complex modeling of rattle phenomenon may not be necessary Project objectives need to be carefully defined
CAViDS Consortium Second Level Model
CAViDS Consortium Second Level Model Input Torsional Vibration 600 rpm idle speed 15 rpm 0-peak oscillation at 30 Hz (engine firing excitation at idle) System Pre-damper Spring 2.25 NM/degree 3 degrees of travel Clutch Hub and Input Shaft 0.002 kg-m^2 inertia 3 degrees of backlash Input Gear 67 mm radius 0.00439 kg-m^2 inertia Countershaft 80 mm radius drive gear 0.012 kg-m^2 inertia 0.5 mm backlash Drag Torque Various levels 0.6 NM calculated threshold of rattle
CAViDS Consortium Second Level Model
CAViDS Consortium Second Level Model Results Tooth Force
CAViDS Consortium Second Level Model Results Tooth Force
CAViDS Consortium Second Level Model Results Tooth Force
CAViDS Consortium Conclusions Results make intuitive sense: Pre-damper spring working as expected Drag torque working as expected Backlash working as expected
CAViDS Consortium Next Steps Define modeling objectives Define model users Define modeling software