Profile Modification for Increasing the Tooth Strength in Spur Gear Using CAD

Shanmugasundaram Sankar, Maasanamuthu Sundar Raj, Muthusamy Nataraj

.

DOI: 10.4236/eng.2010.29096                

Abstract

This paper examines the tooth failure in spur gears. Corrective measures are taken to avoid tooth damage by introducing profile modification in root fillet. In general, spur gear with less than 17 numbers of teeth had the problem of undercutting during gear manufacturing process which minimizes the strength of gear at root. In this study, a novel design method, namely circular root fillet instead of the standard trochoidal root fillet is introduced in spur gear and analyzed using ANSYS version 11.0 software. The strength of these modified teeth is studied in comparison with the standard design. The analysis demonstrates that the novel design exhibit higher bending strength over the standard trochoidal root fillet gear. The result reveals that the circular root fillet design is particularly suitable for lesser number of teeth in pinion and where as the trochoidal root fillet gear is more opt for higher number of teeth.

Keywords

Bending Stress, Circular Root Fillet, Deflection, Profile Modification, Spur Gear, Trochoidal Root Fillet

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	T. Costopoulos and V. Spitas, “Reduction of Gear Fillet Stresses by Using One Sided Involute Asymmetric Teeth,” Mechanism and Machine Theory, Vol. 44, No. 8, 2009, pp. 1524-1534.
[2]	Y. A. Tesfahunegn and F. Rosa, “The Effects of the Shape of Tooth Profile Modification on the Transmission Error Bending and Contact Stress of Spur Gears,” Journal of Mechanical Engineering Science, Vol. 224, No. 8, 2010, pp. 1749-1758.
[3]	V. Spitas, T. Costopoulos and C. Spitas, “In-creasing the Strength of Standard Involute Gear Teeth with Novel Circular Root Fillet Design,” American Journal of Ap-plied Sciences, Vol. 2, No. 6, 2005, pp. 1058-1064.
[4]	L. Fredette and M. Brown, “Gear Stress Reduction Using Internal Stress Relief Features,” Journal of Mechanical Design, Vol. 119, No. 4, 1997, pp. 518-521.
[5]	M. Ciavarella and G. Demelio, “Numerical Methods for the Optimization of Specific Sliding Stress Concentration and Fatigue Life of Gears,” International Journal of fatigue, Vol. 21, No. 5, 1999, pp. 465-474.
[6]	M. S. Hebbal, V. B. Math and B. G. Sheeparamatti, “A Study on Reducing the Root Fillet Stress in Spur Gear Using Internal Stress Relieving Feature of Different Shapes,” International Journal of RTE, Vol. 1, No. 5, May 2009, pp. 163-165.
[7]	S. Senthilvelan and Gnanamoorthy, “Effects of Gear Tooth Fillet Radius on the Performance of Injection Moulded Nylon 6/6 Gears,” Materials and Design, Vol. 27, No. 8, 2005, pp. 632-639.
[8]	T. H. Chong, T. H. Myong and K. T. Kim, “Tooth Modification of Helical Gears for Minimization of Vibration and Noise,” International Journal of KSPE, Vol. 2, No. 4, 2001, pp. 5-11.
[9]	M. Beghini, F. Presicce and C. Santus, “A Method to Define Profile Modification of Spur Gear and Minimize the Transmission Error,” AGMA Fall Technical Meeting, Milwaukee, Wisconsin, October 2004, pp. 1-28.
[10]	ISO, 6336-3, “Calculation of the Load Capacity of Spur and Helical Gears-Part 3,” Calculation of Bending Strength, 1996.
[11]	AGMA, 2101-C95, “Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear (Metric Version),” American Gear Manufacturers Association, 1995.
[12]	H. H. Mabie, C. A. Rogers and C. F. Reinholtz, “Design of Nonstandard Spur Gears Cut by a Hob,” Mechanism and Machine Theory, Vol. 25, No. 6, 1990, pp. 635-644.
[13]	C. A. Rogers, H. H. Mabie and C. F. Reinholtz, “Design of Spur Gears Generated with Pinion Cutters,” Mechanism and Machine Theory, Vol. 25, No. 6, 1990, pp. 623-634.
[14]	G. Niemann,“Maschinenelemente,” Band 2, Springer, Verlag, 1965.