Study on the influence of mixed lubrication friction on gear stress field and associated failure risks
LIU Jian
TIAN Hualiang
LI Luke
CHU Yankui
CAO Changxing
XU Ningbo
WANG Xiaopeng
Abstract：[Objective]Mixed lubrication,as a typical service state of gear transmission,exerts a significant regulatory effect on tooth surface friction characteristics and the meshing stress field distribution.However,the rapid analysis and evaluation of their coupling effects remain insufficient in existing studies.Therefore,an efficient calculation model for the gear tooth stress field was constructed incorporating mixed lubrication friction effects,in order to support the precise prediction of gear transmission failure risks.[Methods]Firstly,a calculation method for the mixed lubrication friction coefficient was derived based on the kinematic relations along the line of action and the load-bearing ratio of asperity contacts,which provided an accurate interface parameter for stress field analysis.Secondly,this friction coefficient was integrated into the gear contact mechanics model to construct a computational framework for stress field distribution and failure risk prediction.Then,the influence laws of characteristic parameters,including rotational speed,roughness,tooth profile modification,and load,on the friction coefficient and stress field were systematically analyzed.Finally,micropitting tests on tooth surfaces with different roughness levels were carried out on a gear contact fatigue test rig to validate the model analysis results.[Results]The results indicate that when the rotational speed increases from 250 r/min to 4 000 r/min,the specific film thickness ratio rises from 0.5 to above 1.0,the lubrication state transitions from boundary to elastohydrodynamic lubrication,and the friction coefficient decreases by approximately 22%.When the tooth surface roughness is reduced from 0.8 μm to 0.4 μm,the specific film thickness ratio approaches or exceeds 1,and the initial micropitting life is delayed by 200%.Appropriate tooth profile modification effectively reduces the stress drop at the transition points between single and double tooth contact zones.As the friction coefficient increases from 0.06 to 0.15,the peak point of the maximum subsurface shear stress migrates toward the surface,significantly exacerbating the risk of crack initiation.
Keywords：Gear pairMixed lubricationOil film bearing ratioFriction coefficientStress field
Publication Date：2026-05-31
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：11( 42-52 )