Prediction of micropitting life in spur gears operating under mixed-lubrication regime using load-sharing concept

Abstract

Micropitting is a surface fatigue failure of the gear tooth that occurs due to repeated loading and unloading of the tooth surface in a manner that the contact stresses exceed the surface fatigue strength of the material. The micropitting process in essence is a fatigue problem and thus it occurs during millions of cycles of operation. Micropitting can lead to problems such as wearing of the gear tooth, vibrations, noise, and misalignment. Therefore, micropitting life prediction is necessary for design, performance, and reliability improvements. The present study predicts the coefficient of friction for each point along the line of action of the pinion and gear using the load-sharing concept. The subsurface stresses are then calculated and the Von Mises stresses at each point are obtained. Then, the pitting life is predicted by employing a model which was developed by Zaretsky. The predicted pitting lives are compared with the experimental data from the literature. A parametric study on the effect of applied load, speed, and surface roughness on the micropitting life of a pair of spur gears is conducted. It is shown that increasing the applied load results in the decrease in the micropitting life of the gear. Increase in the speed, on the other hand, results in formation of a better lubricant film and therefore the micropitting life increases. An increase in the surface roughness leads to a decrease in the micropitting life.

Keywords

Spur gear micropitting life elastohydrodynamic lubrication load-sharing mixed-lubrication

Get full access to this article

View all access options for this article.

References

Lundberg

Palmgren

. Dynamic capacity of rolling bearings. Acta Polytech Mech Eng Ser I 1947; 3(1): 1–50.

Ioannides

Harris

. A new fatigue life model for rolling bearings. ASME J Tribol 1985; 107: 367–378.

Zaretsky

. Fatigue criterion to system design, life and reliability. J Propul Power 1987; 3(1): 76–83.

Blake

Cheng

. A surface pitting life model for spur gears: part I Life prediction. ASME J Tribol 1991; 113: 712–718.

Aslantaş

Taşgetiren

. A study of spur gear pitting formation and life prediction. Wear 2004; 257(11): 1167–1175.

Glodez

Abersek

Flasker

. Evaluation of the service life of gears in regard to surface pitting. Eng Frach Mech 2003; 71(4–6): 429–438.

Düzcükoglu

Imrek

. A new method for preventing premature pitting formation on spur gears. Eng Fract Mech 2008; 75(15): 4431–4438.

Dong

Ning Ren

Jane

. Pitting life prediction based on a 3D lin contact mixed EHL analysis and subsurfacevon misesstress calculation. J Tribol 2009; 131(4): 1–8.

Ren

Zhu

Chen

. A three-dimensional deterministic model for rough surface line-contact ehl problems. ASME J Tribol 2000. 131:011501(1–9).

10.

Kahraman

. A physics-based model to predict micro-pitting lives of lubricated point contacts. Int J Fatigue 2013; 47: 205–215.

11.

Johnson

Greenwood

Poon

. A simple theory of asperity contact in elastohydrodynamic lubrication. Wear 1972; 19: 91–108.

12.

Gelinck

ERM

Schipper

. Calculation of stribeck curve for line contacts. Tribol Int 2000; 33: 175–181.

13.

Khonsari

Gelinck

ERM

. The stribeck curve: experimental results and theoretical prediction. ASME J Tribol 2006; 128: 784–794.

14.

Akbarzadeh

Khonsari

. Performance of spur gears considering surface roughness and shear thinning lubricant. ASME J Tribol 2008; 130(2): 021503–021503.

15.

Akbarzadeh

Khonsari

. Thermoelastohydrodynamic analysis of spur gears with consideration of spur gears. Tribol Lett 2008; 32: 129–141.

16.

Akbarzadeh

Khonsari

. Prediction of steady-state adhesive wear in spur gears using the EHL load sharing concept. ASME J Tribol 2009; 131: 021503–021503.

17.

Akbarzadeh

Khonsari

. Experimental and theoretical investigation of running-in. Tribol Int 2011; 44: 92–100.

18.

Akbarzadeh

Khonsari

. On the prediction of running-in behavior in mixed-lubrication line contact. ASME J Tribol 2010; 32: 032102–032112.

19.

Ebrahimi Serest

Akbarzadeh

. Mixed-elastohydrodynamic analysis of helical gears using load-sharing concept. Proc IMechE, Part J: J Engineering Tribology 2014; 228: 320–331.

20.

Bahrami Ghahnavieh

Akbarzadeh

Mosaddegh

. A numerical study on the performance of straight bevel gears operating under mixed-lubrication regime. Mech Mach Theor 2014; 75: 27–40.

21.

Masjedi

Khonsari

. Film thickness and asperity load formulas for line-contact EHL with provision for surface roughness. J Tribol 2012; 134(1): 011503–011503.

22.

Masjedi

Khonsari

. On the effect of surface roughness in point-contact EHL: Formulas for film thickness and asperity load. Tribol Int 2015; 82: 228–244.

23.

Zhao

Maietta

Chang

. An asperity microcontact model incorporating the transition from elastic deformation to fully plastic flow. Tribology 2000; 122: 86–93.

24.

Briscoe

Scruton

Willis

. The shear strength of thin lubricant films. Philos Trans R Soc London Series A 1973; 333: 99–114.

25.

Roelands

CJA

Vlugter

Waterman

. The viscosity temperature-pressure relationship of lubricating oils and its correlation with chemical constitution. ASME J Basic Eng 1962; 85: 601–610.

26.

Moes

. Optimum similarity analysis with applications to elastohydrodynamic lubrication. Wear 1992; 159(1): 57–66.

27.

Greenwood

Williamson

JBP

. Contact of nominally flat surfaces. Proc R Soc London Ser A 1966, pp. 300–319.

28.

Johnson

. Contact mechanics, UK: Cambridge University Press, 1985.

29.

Brandão

Seabra

JHO

Castro

. Surface initiated tooth flank damage. Part II: Prediction of micropitting initiation and mass loss. Wear 2010; 268: 13–22.