A Comparative Study of Tooth Wear, Mechanical Power Losses and Efficiency in Normal and High Contact Ratio Asymmetric Spur Gears
Subject Areas : Mechanical Engineering
1 - Mechanical Engineering Department, Motilal Nehru National Institute of Technology, Allahabad, India
Keywords: High contact ratio, Wear depth, Direct design, Asymmetric gear, power losses,
Abstract :
The surface tooth wear which occurs at the gear contact region due to inadequate contact strength of the tooth is one of the predominant modes of gear failures. Currently, higher contact ratio spur gears are increasingly used in power transmission applications such as aircraft, wind turbine, automobiles and compact tracked vehicles due to their high load carrying capacity. In this work, the direct design is found to be one of the efficient gear design methods to reduce the tooth surface wear on high contact ratio asymmetric spur gears. Asymmetric gear tooth is defined as one whose tooth geometry of the drive and coast sides is not symmetric. Asymmetry between tooth sides is achieved by providing two different pressure angles at the respective coast and drive side pitch circles. The area of existence diagrams for normal and high contact ratio gears have been developed to select suitable design solution with the given variables of gear ratio, contact ratio and teeth number. The contact load capacity, wear resistance, power losses and mechanical efficiency have also been deduced for directly designing normal and high contact ratio asymmetric spur gears.
[1] Elkholy A.H., 1985, Tooth load sharing in high contact ratio spur gears, Journal of Mechanisms, Transmissions, and Automation in Design 107: 11-16.
[2] Tsai M.H., Tsai Y.C., 1997, Design of high contact ratio spur gears using quadratic parametric tooth profiles, Mechanism and Machine Theory 33: 551-564.
[3] Arafa M.H., Megahed M.M., 1999, Evaluation of spur gear mesh compliance using finite element method, Proceedings of the Institution of Mechanical Engineers Part C, Journal of Mechanical Engineering Science 213: 569-579.
[4] Saribay Z. B., 2012, Tooth geometry and bending stress analysis of conjugate meshing face-gear pairs, Proceedings of the Institution of Mechanical Engineers Part C, Journal of Mechanical Engineering Science 227: 1302-1314.
[5] Wang J., Howard I., 2005, Finite element analysis of high contact ratio spur gears in mesh, Journal of Tribology 127: 469-483.
[6] Li S., 2007, Effect of addendum on contact strength, bending strength and basic performance parameters of a pair of spur gears, Mechanism and Machine Theory 43: 1557-1584.
[7] Pedrero J., Vallejo I., Pleguezuelos M., 2007, Calculation of tooth bending strength and surface durability of high transverse contact ratio spur and helical gear drives, Journal of Mechanical Design 129: 69-74.
[8] Basan R., Franulović M., Križan B., 2008, Numerical model and procedure for determination of stresses in spur gears teeth flanks, XII International Conference on Mechanical Engineering, Bratislava, Slovakia.
[9] Sivakumar P., Kopinath K., Sundaresh S., 2009, Performance evaluation of high-contact-ratio gearing for combat tracked vehicles – a case study, Proceedings of the Institution of Mechanical Engineers Part D, Journal of Automobile Engineering 224: 631-643.
[10] Thirumurugan R., Muthuveerappan G., 2011, Critical loading points for fillet and contact stresses in normal and high contact ratio spur gears based on load sharing ratio, Mechanics Based Design of Structures and Machines 39: 118-141.
[11] Archard A. F., 1953, Contact of rubbing flat surfaces, Journal of Applied Physics 24: 981-988.
[12] Wu S., Cheng H.S., 1993, Sliding wear calculation in spur gears, ASME Journal of Tribology 115: 493-503.
[13] Flodin A., Andersson S., 1997, Simulation of mild wear in spur gears, Wear 207: 123-128.
[14] Mao K., 2007, Gear Tooth contact analysis and its application in the reduction of fatigue wear, Wear 262: 1281-1288.
[15] Imrek H., Duzcukoglu H., 2007, Relation between wear and tooth width modification in spur gears, Wear 262: 390-394.
[16] Imrek H., Unuvar A., 2009, Investigation of influence of load and velocity on scoring of addendum modified gear tooth profiles, Mechanism and Machine Theory 44: 938-948.
[17] Chernets M., Chernets J., 2016, The simulation of Influence of engagement conditions and technological teeth correction on contact strength, wear and durability of cylindrical spur gear of electric locomotive, Journal Engineering Tribology 231: 57-62.
[18] Bergseth E., Sjoberg S., Bjorklund S., 2012, Influence of real surface topography on the contact area ratio in differently manufactured spur gears, Tribology International 56: 72-80.
[19] Parsa M., Akbarzadeh S., 2014, A new load sharing based approach to model mixed-lubrication contact of spur gears, Journal Engineering Tribology 228: 1319-1329.
[20] Zhang J., Liu X., 2015, Effects of misalignment on surface wear of spur gears, Journal Engineering Tribology 229: 1145-1158.
[21] Prabhu Sekar R., Sathish Kumar R., 2017, Enhancement of wear resistance on normal contact ratio spur gear pairs through non-standard gears, Wear 380-381: 228-229.
[22] Kapelevich A., 2000, Geometry and design of involute spur gears with asymmetric teeth, Mechanism and Machine Theory 35: 117-130.
[23] Karpat F., Osire S.E., 2008, Influence of tip relief modification on the wear of NCR spur gears with asymmetric teeth, Tribology Transactions 51: 581-588.
[24] Litvin F.L., Perez I.G., Fuentes A., Hayasaka K., 2008, Design and investigation of gear drives with non-circular gears applied for speed variation and generation function, Computer Methods in Applied Mechanics and Engineering 197: 3783-3802.
[25] Costopoulos T., Spitas V., 2009, Reduction of gear fillet stresses using one side asymmetric teeth, Mechanism and Machine Theory 44: 1524-1534.
[26] Muni D.V., Muthuveerappan G., 2009, A comprehensive study on the asymmetric internal spur gear drives through direct and conventional gear design, Mechanics Based Design of Structures and Machines 37: 431-461.
[27] Alipiev O., 2011, Geometric design of involute spur gear drives with symmetric and asymmetric teeth using the Realized Potential Method, Mechanism and Machine Theory 46: 10-32.
[28] Prabhu Sekar R., Muthuveerappan G., 2015, Estimation of tooth form factor for normal contact ratio asymmetric spur gear tooth, Mechanism and Machine Theory 90: 187-218.
[29] Maitra G.N.,2001, Handbook of Gear Design, Tata MaGraw-Hill Pubns.
[30] Xu H., Kahraman A., Anderson N., Maddock D., 2007, Prediction of mechanical efficiency of parallel-axis gear pairs, Journal of Mechanical Design 129: 58-68.
[31] Hamrock B.J., Dowson O., 1977, Isothermal elastohydrodynamic lubrication of point contacts, fully flooded results, Journal of Lubricatton Technology 99: 264-276.
[32] Anderson N.E., Loewenthal S.H., 1980, Spur-Gear-System efficiency at part and full load, NASA TP-1622.
[33] Cheng H.S., 1974, Prediction of film thickness and sliding frictional coefficient in elastohydrodynamic contacts, Design Engineering Technology Conference, American Society of Mechanical Engineers.
[34] Maitra G.M., 1989, Hand Book of Gear Design, Tata McGraw Hill Publishing Company Limited, New Delhi.