Parametric design has been playing an important role in modern manufacturing industry where people need the virtual models in short period of time to do calculation, simulation and analysis before the production processes. Hence, expensive costs for experiments are considerably reduced. Gears are crucial components in engines, machine tools, and mechanical devices, etc. The development of 3-D model parametric design for gears is essential in mechanical design and manufacturing. It does not only diminish the time for designing, but also intuitively provides the view of models as real products. Parametric design of 3-D models for shifted gears is presented in this thesis under program tools inside Pro/Engineer software. This thesis proposes solution for following problems:

1. Firstly, based on theory of gears and gear design, proper sequences of geometrical calculations for typical gear types in mechanical engineering are described. These calculation sequences are necessary not only for gear design, but they are also used in manufacturing and inspection of gears. These calculation procedures are concisely presented for following gear types:
• Parallel axes gears such as external spur gears, internal spur gear, helical gears, herringbone gears, internal helical gear, spur gear and rack, helical gear - rack, double helical gear -rack.
• Intersecting axes gears such as straight bevel gears, spiral bevel gears, skew bevel gears, Zerol bevel gears.
• Non-paralleled, non-intersecting axes gears such as crossed axes helical gears, cylindrical worm gears.
2. Secondly, processes to create 3-D parametric models for the above gear types under program tools inside Pro/Engineer are mentioned in details. Proper sequences from input parameters to output results of parametric gear models are presented steps by steps. The results are 3-D gear models at both part level and assembly level in which Pro/Engineer users can change any of input parameter to create new models quickly without recreate gear models from the beginning.
3. In addition, proper assembly methods of 3-D models for all the above gear types are proposed in this thesis. Therefore, two mating gear models are assembled in exact position.
4. Finally, methods to create report tables of gear parameters in the form of Excel file from Pro/Engineer models are presented in details. This excel file, which has online relation with input parameters of gears model in Pro/Engineer, can be updated automatically when any of input parameters are changed. Moreover, these tables also provide important of parameters and dimensions, which are used in manufacturing, measurement, and inspection of gears.

From the result of this research, it is possible for 3-D gears design software to be developed.

Parametric design has been playing an important role in modern manufacturing industry where people need the virtual models in short period of time to do calculation, simulation and analysis before the production processes. Hence, expensive costs for experiments are considerably reduced. Gears are crucial components in engines, machine tools, and mechanical devices, etc. The development of 3-D model parametric design for gears is essential in mechanical design and manufacturing. It does not only diminish the time for designing, but also intuitively provides the view of models as real products. Parametric design of 3-D models for shifted gears is presented in this thesis under program tools inside Pro/Engineer software. This thesis proposes solution for following problems:

1. Firstly, based on theory of gears and gear design, proper sequences of geometrical calculations for typical gear types in mechanical engineering are described. These calculation sequences are necessary not only for gear design, but they are also used in manufacturing and inspection of gears. These calculation procedures are concisely presented for following gear types:
• Parallel axes gears such as external spur gears, internal spur gear, helical gears, herringbone gears, internal helical gear, spur gear and rack, helical gear - rack, double helical gear -rack.
• Intersecting axes gears such as straight bevel gears, spiral bevel gears, skew bevel gears, Zerol bevel gears.
• Non-paralleled, non-intersecting axes gears such as crossed axes helical gears, cylindrical worm gears.
2. Secondly, processes to create 3-D parametric models for the above gear types under program tools inside Pro/Engineer are mentioned in details. Proper sequences from input parameters to output results of parametric gear models are presented steps by steps. The results are 3-D gear models at both part level and assembly level in which Pro/Engineer users can change any of input parameter to create new models quickly without recreate gear models from the beginning.
3. In addition, proper assembly methods of 3-D models for all the above gear types are proposed in this thesis. Therefore, two mating gear models are assembled in exact position.
4. Finally, methods to create report tables of gear parameters in the form of Excel file from Pro/Engineer models are presented in details. This excel file, which has online relation with input parameters of gears model in Pro/Engineer, can be updated automatically when any of input parameters are changed. Moreover, these tables also provide important of parameters and dimensions, which are used in manufacturing, measurement, and inspection of gears.

From the result of this research, it is possible for 3-D gears design software to be developed.

[1] Faydor L. Litvin, Alfonso Fuentes, “Geometry and Applied Theory”, Second Edition 2004, Cambridge University Press.
[2] L.Y. Wang, “Elements of Gear Technology”, First Edition 1993, Editional Cooperater: Kohara Gear Industry Co.Ltd. Japan.
[3] G.M. Maitra, “Handbook of Gear Design”, Tata McGraw-Hill Publishing Co.Ltd. 1988.
[4] Dennis P. Townsend, “Dudley’s Gear Handbook”, Second Edition 1962, McGraw-Hill Inc.
[5] Z.H. Fong, Tsay. C.B “a Mathematical Model for the Tooth Geometry of Circular-Cut Spiral Bevel Gears” Transactions of the ASME 174/ Vol. 113, June 1991.
[6] Lin Ai-Qin, Huang Kai, “3D Parametric Modeling of Spiral Bevel Gears under Pro/E”, Journal of Liaoning Institute of Tech. Vol. 24, No. 5, 2004.
[7] V. M. Drecun, T. A. Dean, “A Parametric CAD Program for Die Sets for Precision Forging Spur Gears”, Int. J. Mach. Tools Manufact. Vol.31. No.2, pp183-191, 1991.
[8] Joseph E. Shigley, Charles R. Mischke, “Standard handbook of Machine Design”, Second Edition, A Division of The McGraw-Hill Companies, 1996.
[9] Darle W. Dudley, “Practical Gear Design”, McGraw-Hill Book Company, Inc. 1954.
[10] Litvin, F. L., Chiang, W. S., Kuan, C., Lundy, M., and Tsung, W. J., “Generation and Geometry of Hypoid Gear-Member with Face-Hobbed Teeth of Uniform Depth,” Int. J. of Mach. Tools Manufacturing., 31(2), 1991, pp 167-181.
[11] Lelkes, M., Marialigeti, J., and Play, D., “Numerical Determination of Cutting Parameters for the Control of Klingelnberg Spiral Bevel Gear Geometry,” ASME J. Mech. Des., 124(4), pp 761-771.
[12] Fred H. Colvin, Frank A. Stanley, “Gear Cutting Practice – Methods of Producing Gears for Commercial Use”, Third Edition, McGraw-Hill Book Company, Inc. 1950.
[13] W.A. Tuplin, “Gear Design”, the Machinary Publishing Co.Ltd. 1962.
[14] John Vince, “Geometry for Computer Graphics: Formulae, Examples and Proofs”, Springer-Verlag London Limited 2005.
[15] Erik Oberg, Franklin D. Jones, Holbrook L. Horton, And Henry H. Ryffel, “Machinery’s Handbook”, 27th Edition, Industrial Press Inc. New York, 2004.
[16] Earle Buckingham, “Analytical Mechanics of Gears”, McGraw-Hill Book Company 1949.
[17] S. J. Tsai, S. H. Wu, “Geometrical Design of Conical Gear Drives with Profile-shifted Transmission”, 12th IFToMM World Congress, Besançon (France), June18-21, 2007.