Optimization of Tolerance Grades of a Bearing and Shaft Assembly in a Washing Machine with Regard to Fatigue Life
The drum is one of the critical parts in a washing machine in which the clothes are washed and spin by the rotational movement. It is activated by the drum shaft which is attached to an electric motor and subjected to dynamic loading. Being one of the critical components, failures of the drum require costly repairs of dynamic components. In this study, tolerance bands between the drum shaft and its two bearings were examined to develop a relationship between the fatigue life of the shaft and the interaction tolerances. Optimization of tolerance bands was completed in consideration of the fatigue life of the shaft as the cost function. The following methodology is followed: multibody dynamic model of a washing machine was constructed and used to calculate dynamic loading on the components. Then, these forces were used in finite element analyses to calculate the stress field in critical components which was used for fatigue life predictions. The factors affecting the fatigue life were examined to find optimum tolerance grade for a given test condition. Numerical results were verified by experimental observations.
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1340558Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 541
 J. Schijve. Fatigue of Structures and Materials. Springer, 2008.
 A. Halfpenny, A frequency domain approach for fatigue life estimation from finite element analysis. In M. D. Gilchrist, J. M. Dulieu Barton, and K. Worden, editors, DAMAS 99: Damage Assessment of Structures, volume 167-1 of Key Engineering Materials, pages 401-410, 1999.
 M. Matsuishi, T. Endo, Fatigue of metals subject to varying stress. Paper presented to Japan Society of Mechanical Engineers, Fukuoka, Japan, 1968.
 ASTM Designation E 1049-85 (1985). Standard practises for cycle counting in fatigue analysis.
 S. D. Downing, D. F. Socie (1982). “Simple rainflow counting algorithms.” Int. J Fatigue, January 1982, pp 31-40.
 A. Palmgren, Die lebensdauer von kugellagern. VDI-Zeitschrift, 68:339-341, 1924.
 M. A. Miner, Cumulative damage in fatigue. J. Appl. Mech., 12: A159-A164, 1945.
 E. Haibach, Betriebsfestigkeit-Verfaren und Daten zur Bauteliberechnung, Springer Berlin Heidelberg, 2006.
 I. Rychlik, Fatigue and stochastic loads, Scand. J. Stat., 23(4):387-404, 1996.
 W. Zhao, M. J. Baker, On the probability density function of rainow stress range for statonary gaussian processes. Int. J. Fatigue, 14(2):121- 135, March 1992.
 R. Tovo, Cycle distribution and fatigue damage under broad-band random loading. Int. J. Fatigue, 24(11):1137-1147, 2002.
 G. Petrucci, B. Zuccarello, Fatigue life prediction under wide band random loading. Fatigue & Fract. Eng. Mater. & Struct., 27(12):1183- 1195, December 2004.
 ISO 286-2. Geometrical product specifications (GPS) -- ISO code system for tolerances on linear sizes -- Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts, International Organization for Standardization, 2010.
 C. Ersoy, M. Cangi, T. Dolar, Tolerance Analysis, Optimization, FEM Analysis and DOE of the Bearings and Drum Shaft of a Washing Machine. B.Sc. Graduation Cap Stone Design Project, Faculty of Mechanical Engineering, Istanbul Technical University, 2018.