齿轮弹流润滑理论及其在变位齿轮中的应用研究综述OA

With the continuous advancement of modern equipment manufacturing toward higher load capacity,higher rotational speed,and improved reliability,the performance requirements for gear transmission systems in wind power,aerospace,automotive engineering and precision machinery have become increasingly stringent.To meet the growing demands for enhanced transmission efficiency,improved load-carrying capability and extended service life,the research on elastohydro-dynamic lubrication(EHL)has become an essential foundation in the design and optimization of advanced gear systems. The work aims to provide a detailed examination of the development of lubrication theories for standard gears and profile-shifted gears.The evolution was traced from early constant-viscosity rigid lubrication models and idealized Hertzian elastic contact assumptions to the contemporary thermal elastohydrodynamic lubrication(TEHL)and transient EHL models.This progression demonstrated a clear shift from simplified mechanical descriptions toward multi-field coupled analyses incorporating thermal effects,transient effects,complex rheology and real surface conditions.Regarding affecting factors,major advances in understanding lubrication characteristics of gears and profile-shifted gears were summarized.The profile shift coefficient was found to play a central role in modifying local curvature,meshing kinematics and contact load distribution,which directly affected minimum film thickness and pressure distribution across the tooth surface.Positive profile shift generally helped maintain thicker lubricant oil films and reduced contact stress concentrations,while negative profile shift tended to create thin-film regions that increased the risk of micro-contact and lubrication deterioration.Thermal and transient effects became particularly significant at high speeds and heavy loads.Temperature rise lowered lubricant viscosity and weakened load-carrying capacity,causing an overall reduction in film thickness,while the sliding-rolling interaction produced periodic changes in contact characteristics.Non-Newtonian characteristics,especially shear thinning under high shear rates,further altered the internal flow and stress fields within the EHL contact zone.Load and speed exhibited clear and predictable effects.Higher load led to a thinner film and increased pressure peaks,while greater rotational speed enhanced lubricant entrainment,thickened the film and generally reduced hydrodynamic pressure levels.Surface micro-geometry was also identified as a critical factor.Since roughness height was often comparable to oil-film thickness,mixed lubrication conditions frequently arise,in which asperity contact might occur and cause localized film rupture and subsurface fatigue damage.Proper tooth surface modifications improved the distribution of contact stress,reduced edge-loading phenomena and significantly enhanced lubrication stability and fatigue resistance.In addition,the governing equations of gear EHL were summarized,including the Reynolds equation,the film thickness relation,viscosity-pressure and viscosity-temperature equations,density variations and the energy equation.Typical numerical approaches such as direct iteration,inverse solution,Newton-Raphson iterative procedure,finite element methods and multigrid algorithms were discussed in terms of their applicability and efficiency for solving complex gear EHL problems. Finally,the work presented future research perspectives focusing on the coupling mechanisms under complex operating conditions,the effect of plastic deformation on lubrication characteristics,the integration of high-fidelity experiments with advanced numerical simulations and the potential of molecular dynamics for revealing lubrication mechanisms at nanometer scales.These developments are expected to further advance the understanding and engineering application of elastohydro-dynamic lubrication in modern gear systems.