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Damage Matching Criterion for Development of Accelerated Duty Cycle from Road Load Data, and Achieving Right Duty Cycle to Determine Gear and Bearing Durability
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 11, 2019 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
Event: International Conference on Advances in Design, Materials, Manufacturing and Surface Engineering for Mobility
While designing the transmission, designer needs to have a duty cycle which is a set of load cases against which he wants to confirm the durability of the same. This is done through data acquisition by running a vehicle on various terrains and converting those data points to a concise set of load cases which we term as duty cycle. This concise set of load cases required because data acquired has millions of data points giving value of torque and RPM at every millisecond which cannot be directly used to assess the fatigue durability of gears and bearings. Converting these millions of road load data points into fewer number of load cases is always a challenge. For a transmission designer, it is being a major hurdle to determine as what is the scientific way of converting these millions of data points into a concise duty cycle. The road load data is taken for few hundred or few thousand kilometres covering enough types of terrains on which vehicle is expected to run. The methods available with today’s engineers does not establish the relation between duration of collected road load data and expected transmission life and duration of test rig. The designer does not know whether the millions of data points are being represented correctly in the fewer load cases while evaluating the durability of the gears and bearing in the transmission or any geared drive for that matter.
The calculation of equivalent load of the data points from road load data which is a torque, RPM and duration can be moved along SN curve to convert given torque and RPM to higher torque and rpm. This is the easiest way which many engineers are following using a binning method. However, calculation of equivalent load by binning method does not confirm that the cumulative damage due to the number of load cases in a bin is equal to the damage by a condensed equivalent load.
The method developed at Romax is unique and confirms that the damage caused due millions of data point of a road load data for gear contact, gear bending and bearing damage (roller and ball both) for all gears and bearings in a system is equal to the damage caused by condensed duty cycle. This is done in one single analysis run. Moreover, the one can develop a test duty cycle for same damage with specified single torque or RPM or for fixed duration.
CitationKorde, A., "Damage Matching Criterion for Development of Accelerated Duty Cycle from Road Load Data, and Achieving Right Duty Cycle to Determine Gear and Bearing Durability," SAE Technical Paper 2019-28-0121, 2019, https://doi.org/10.4271/2019-28-0121.
Data Sets - Support Documents
|[Unnamed Dataset 1]|
- Romax Technology Limited , “RomaxDesigner Technical Note 118-TN-RI - Gear Design and Transmission Error Theory,” 2002.
- ISO 6336 , “Calculation of Load Capacity of Spur and Helical Gear - Part 2 - Calculation of Surface Durability (Pitting),” 1996.
- ISO 6336 , “Calculation of Load Capacity of Spur and Helical Gear - Part 6 - Calculation of Service Life Under Variable Load,” 2006.
- DIN 3990 , “Calculation of Load Capacity of Cylindrical Gears”.
- AGMA 6003-A03.
- ISO 281 , 1990 (E).
- Shigley, J.E., Mischke, C.R., and Budynas, R.G. , Mechanical Engineering Design 7th Edition (McGraw Hill Higher Education, 2003).
- James, B. et al. , “Predicting Unequal Planetary Load Sharing Due to Manufacturing Errors and System Deflections, with Validation against Test Data,” SAE Technical Paper 2002-01-0699, 2002, doi:10.4271/2002-01-0699.
- James, B., Potter, T., Coultate, J., Jain, S. et al. , “Re-Evaluating the Effect of Engine Firing on Transmission Durability,” in Proceedings CTI Symposium, Berlin, December 2007.
- Harris, O.K., James, B.M., and Woolley, A.M. , “Predicting the Effects of Housing Flexibility and Bearing Stiffness on Gear Misalignment and Transmission Noise Using a Fully Coupled Non-Linear Hyperstatic Analysis,” in Proc. Inst. Mech. Eng., C577/005/2000, May 2000.
- James, B.M. et al. , “Development of a Gear Whine Model for the Complete Transmission System,” SAE Technical Paper 2002-01-0700, 2002, doi:10.4271/2002-01-0700.