EHL oil film thickness analysis of VH-CATT cylindrical gears based on parabolic blade modification
MA Dengqiu
BAO Linli
JIANG Bing
YE Zhenhuan
Abstract：[Objective]Previous studies on variable hyperbolic circular-arc-tooth-trace(VH-CATT)cylindrical gears have primarily focused on contact characteristics and mesh stiffness,with limited research on the lubrication aspects of this gear type,particularly in the calculation of oil film thickness.It is necessary to further investigate the influence of tooth profile modification on the oil film thickness of the meshing tooth surface in variable hyperbolic circular-arc-tooth-trace cylindrical gear transmissions.[Methods]Firstly,based on the parabolic blade tooth profile modification method,the equation of the modified tooth surface was derived.Secondly,a tooth surface contact analysis model was established based on contact analysis theory,and combined with classical elasto-hydrodynamic lubrication(EHL)theory,dynamic parameter expressions related to elastohydrodynamic lubrication were derived to develop an oil film thickness model.Finally,the variation laws of the minimum and central EHL oil film thicknesses on the meshing tooth surface of VH-CATT cylindrical gears during engagement were analyzed with respect to modification parameters,rotational speed,and torque.[Results]The results indicate that from the engagement region to position t,both the EHL central oil film thickness and minimum oil film thickness decrease with increasing parabolic coefficient;from position t to the disengagement region,the oil film thickness increases with increasing parabolic coefficient.The EHL central and minimum oil film thicknesses decrease with an increase in the parabolic vertex position,increase significantly with rising input rotational speed,and exhibit a decreasing trend with increasing input torque.These findings provide a basis for the lubrication characteristics and tooth surface optimization design of modified VH-CATT cylindrical gears.
Keywords：VH-CATT cylindrical gearModified designElasto-hydrodynamic lubricationCentral oil film thicknessMin-imum oil film thickness
Publication Date：2025-12-15
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：9( 38-46 )