Elliptical lobe shape gerotor pump design to minimize wear

Abstract

The gerotor pumps are the most important parts of mechanical equipment that have a vast number of applications in industries and automobiles. Because the gerotor pumps cannot be adjusted for wear so it is important to reduce the wear as much as possible. In this paper first mathematical equations for elliptical lobe shape rotors profile and curvature of them have been derived and then Specific flow and wear rate proportional factor (WRPF) have been formulated. To reach the minimum wear in rotors teeth, the ellipse shape factor is changed for each value of number of outer rotor teeth in a feasible range and wear rate proportional factor has been resulted. Also in order to have better comparison specific flow has been presented. The obtained results have been compared with circular pumps with similar geometrical parameters and show the significant improvement in wear of the rotors with negligible changes in the specific flow.

Keywords

gerotor pump / elliptical lobe shape pump / wear rate proportional factor (WRPF) / specific flow

References

[1] Vecchiato D, Demenego A, Argyris J, Litvin F L. Geometry of a cycloidal pump. Computer Methods in Applied Mechanics and Engineering, 2001, 190(18-19): 2309-2330

[2] Chen B K, Fang T T, Li C Y, Wang S Y. Gear geometry of cycloid drives. Science in China, Series E: Technology Sciences, 2008, 51(5): 598-610

[3] Hwang Y W, Hsieh C F. Geometry design and analysis for Trochoidal type speed reducers with conjugate envelopes. Transactions of the Canadian Society for Mechanical Engineering, 2006, 30: 261-278

[4] Hwang Y W, Hsieh C F. Determination of surface singularities of a cycloidal gear drive with inner meshing. Mathematical and Computer Modeling, 2007, 45(3-4): 340-354

[5] Ivanović L, Josifović D. Specific sliding of trochoidal gearing profile in the gerotor pumps. FME Transactions, 2006, 34(3): 121-127

[6] Chang Y J, Kim J H, Jeon C H, Kim C, Jung S Y. Development of an integrated system for the automated design of a gerotor oil pump. Journal of Mechanical Design, 2007, 129(10): 1099-1105

[7] Kwon S M, Kim M S, Shin J H. Analytical wear model of a gerotor pump without hydrodynamic effect. Journal of Advanced Mechanical Design, Systems, and Manufacturing, 2008, 2: 230-237

[8] Gamez-Montero P J, Castilla R, Mujal R, Khamashta M, Codina E. GEROLAB package system: innovative tool to design a trochoidal-gear pump. Journal of Mechanical Design, 2009, 131(7): 074502

[9] Demenego A, Vecchiato D, Litvin F L, Nervegna N, Manco S. Design and simulation of meshing of a cycloidal pump. Mechanism and Machine Theory, 2002, 37(3): 311-332

[10] Gamez-Montero P J, Castilla R, Khamashta M, Codina E. Contact problems of a trochoidal-gear pump. International Journal of Mechanical Sciences, 2006, 48(12): 1471-1480

[11] Kim J H, Kim C, Chang Y J. Optimum design on lobe shapes of gerotor oil pump. Journal of Mechanical Science Technology, 2006, 20(9): 1390-1398

[12] Inaguma Y. Calculation of theoretical torque and displacement in an internal gear pump. Koyo Engineering Journal, 2006, 1001E: 70-76

[13] Maiti R, Sinha G L. Kinematics of active contact in modified epitrochoid generated rotary piston machines. Mechanism and Machine Theory, 1988, 23(1): 39-45

[14] Shung J B, Pennock G R. The direct contact problem in a trochoidal-type machine. Mechanism and Machine Theory, 1994, 29(5): 673-689

[15] Beard J E, Yannitell D W, Pennock G R. The effects of the generating pin size and placement on the curvature and displacement of epitrochoidal gerotors. Mechanism and Machine Theory, 1992, 27(4): 373-389

[16] Mimmi G C, Pennacchi P E. Involute gear pumps versus lobe pumps: A comparison. Journal of Mechanical Design, 1997, 119(4): 458-465

[17] Mimmi G C, Pennacchi P E. Rotor design and optimization in internal lobe pumps. Applied Mechanics Reviews, 1997, 50(11): 133-141

[18] Jung S Y, Han S M, Cho H Y, Kim C. Automated design system for a rotor with an ellipse lobe profile. Journal of Mechanical Science Technology, 2009, 23(11): 2928-2937

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Higher Education Press and Springer-Verlag Berlin Heidelberg