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Minimizing Tooth Mesh Misalignment in Heavy Duty Tractor Transmission
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 27, 2016 by SAE International in United States
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In any drive system, tooth mesh misalignment originates primarily from its torque transmitting components such as spline connections, gears, shafts, bearings and housing. The major influencing factors for tooth mesh misalignments are clearance between components, deflection, stiffness, thermal expansion, manufacturing limitations and assembly limitations. Tooth mesh misalignments in heavy duty off-highway applications like tractor, propagates drastically while handling severe loads and tends to shift the load distribution in a gear pair to an un-biased manner along the facewidth, resulting in high contact stresses and poor transmission performance. Misalignments definitely add few more decibels to the driveline system which will be an annoyance to the user. Moreover, mesh misalignments in any drive system cannot be eliminated and hence different approaches and methods were followed to compensate the misalignment.
Current tractor drivelines are geared up to accommodate new technologies and updates experienced throughout the industry. One such phenomenon is the use of wet clutch in forward and reverse tractor application. The applications include agriculture, livestock, construction, material handling, etc. In all such heavy duty tractor applications in particular, gears that are connected with the wet clutch assembly experiences severe cyclic loading and duty cycle. Misalignments in this case, will directly affect the performance of drive system to a substantial amount.
This paper revolves on the case study of two factors influencing mesh misalignment: (1) bearing offset and (2) gear hub, as an initiative to minimize the amount of tooth mesh misalignment on gear pair. Advanced driveline analysis tools like KISSsoft and MASTA were used to analyze and calculate the amount of misalignment on the gear tooth mesh. The optimized gear pair showed more than 40% reduction in tooth mesh misalignment and more than 10% reduction in peak contact stress during initial design stage.
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CitationRajagopal, M., Kumar N, S., and Rao P, N., "Minimizing Tooth Mesh Misalignment in Heavy Duty Tractor Transmission," SAE Technical Paper 2016-01-8069, 2016, https://doi.org/10.4271/2016-01-8069.
- Houser. Donald R., Harianto. Jonny, and Talbot. David, "Gear Mesh Misalignments," in Gear Solutions magazine, June, 2006.
- Litvin, F. L., Lian, Q., and Kapelevich, A. L., "Asymmetric Modified Spur Gear Drives: Reduction of Noise, Localization of Contact, Simulation of Meshing and Stress Analysis," Comput. Methods Appl. Mech. Engrg. 188(2000), pp. 363-390.
- Tarutani, I. and Maki, H., "A New Tooth Flank Form to Reduce Transmission Error of Helical Gear," SAE Technical Paper 2000-01-1153, 2000, doi:10.4271/2000-01-1153.
- Podzharov. Evgueni, Mozuras. Almantas, Sanchez. Jesus A. Alvarez, "Design of high contact ratio spur gears to reduce static and dynamic transmission error," Ingenieria Mecanica, Septiembre 2003, Vol. 1.
- Roda-Casanova, V., Iserte-Vilar, J. L., Sanchez-Marin, F. T., Fuentes, A., Gonzalez-Perez, I., "Development and comparison of shaft-gear models for the computation of gear misalignments due to power transmission," Proceedings of the ASME 2011 International Design Engineering Technical Conferences, Washington, DC, USA.
- Gonzalez-Perez, I., Roda-Casanova, V., Fuentes, A., "Modified geometry of spur gear drives for compensation of shaft deflections," Springer Science+Business Media Dordrecht 2015, Meccanica, doi:10.1007/s11012-015-0129-9.
- Koide, T., Oda, S., Matsuura, S., " Equivalent Misalignment of Gears due to Deformation of Shafts, Bearings and Gears -(Model Proposal and Development of Calculation Program)," JSME International Journal, Series C, Mechanical Systems, Machine Elements and Manufacturing, Vol.46, no.4, 2003, pp. 1563-1571.
- Ganti, V., Dewangan, Y., and Subramanian, G., "Influence of Gear Web and Macro Geometry on Mesh Misalignment," SAE Technical Paper 2016-28-0082, 2016, doi:10.4271/2016-28-0082.
- Harris O.J., Douglas M., James B.M., Woolley A.M., Lack L.W., "Predicting the Effects of Transmission Housing Flexibility and Bearing Stiffness on Gear Mesh Misalignment and Transmission Error", Proceedings of 2nd MSC Worldwide Automotive Conference, 2000.
- Ameen. Hani Aziz, "Effect of Shaft Misalignment on the Stresses Distribution of Spur Gears," Eng. & Tech. Journal, Vol.28, no.7, 2010
- Litvin, F. L., Kim, D. H., "Computerized Design, Generation and Simulation of Meshing of Modified Involute Spur Gears With Localized Bearing Contact and Reduced Level of Transmission Errors" Journal of Mechanical Design, Vol.119(1), 1997, pp. 96-100.
- Wang. Jiande, "Numerical and Experimental analysis of Spur gears in mesh," Doctoral thesis, Curtin University, 2003