A fatigue model for spiral bevel gears under mixed elastohydrodynamic lubrication conditions

2021 ◽  
Author(s):  
Wei Cao ◽  
Wei Pu ◽  
Di Wang ◽  
Yu Yang ◽  
Xuanqiu Li ◽  
...  
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Fatigue Model ◽  
Spiral Bevel ◽  
Lubrication Conditions

scholarly journals Contact stiffness and damping of spiral bevel gears under transient mixed lubrication conditions

Friction ◽  
2021 ◽  
Author(s):  
Zongzheng Wang ◽  
Wei Pu ◽  
Xin Pei ◽  
Wei Cao
Keyword(s):  
Contact Stiffness ◽  
Mixed Lubrication ◽  
Asperity Contact ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Dry Contact ◽  
Spiral Bevel ◽  
Stiffness And Damping ◽  
Lubrication Conditions ◽  
Film Lubrication

AbstractExisting studies primarily focus on stiffness and damping under full-film lubrication or dry contact conditions. However, most lubricated transmission components operate in the mixed lubrication region, indicating that both the asperity contact and film lubrication exist on the rubbing surfaces. Herein, a novel method is proposed to evaluate the time-varying contact stiffness and damping of spiral bevel gears under transient mixed lubrication conditions. This method is sufficiently robust for addressing any mixed lubrication state regardless of the severity of the asperity contact. Based on this method, the transient mixed contact stiffness and damping of spiral bevel gears are investigated systematically. The results show a significant difference between the transient mixed contact stiffness and damping and the results from Hertz (dry) contact. In addition, the roughness significantly changes the contact stiffness and damping, indicating the importance of film lubrication and asperity contact. The transient mixed contact stiffness and damping change significantly along the meshing path from an engaging-in to an engaging-out point, and both of them are affected by the applied torque and rotational speed. In addition, the middle contact path is recommended because of its comprehensive high stiffness and damping, which maintained the stability of spiral bevel gear transmission.

Numerical Analysis on Starved Elastohydrodynamic Lubrication Characteristics of Spiral Bevel Gears

2009 ◽  
Vol 16-19 ◽  
pp. 254-258 ◽  
Author(s):  
Yu Tao Yan ◽  
Zhi Li Sun ◽  
Qiang Yang ◽  
Yan Zhong Wang
Keyword(s):  
Numerical Analysis ◽  
Film Thickness ◽  
Gear Tooth ◽  
Elastohydrodynamic Lubrication ◽  
Analysis Model ◽  
Film Pressure ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Spiral Bevel ◽  
Lubrication Characteristics

The spiral bevel gears of attack helicopter transmission systems are taken as an object in this paper. The numerical analysis model for starved elastohydrodynamic lubrication (SEHL) of spiral bevel gears is established on the basis of the analysis of load tooth contacts analysis and SEHL in elliptical contacts. The SEHL characteristics of spiral bevel gears are also analyzed. The results are as follows: during the course of a gear-tooth meshing cycle of the spiral bevel gear, the extremum of minimal film thickness and maximal film pressure occurs near midpoint of the path of contact, and leans to dedendum. The minimal value of the minimal film thickness is 0.39 um, and the maximal value of the maximal film pressure is 0.69 GPa. The value of minimal film thickness gradually increases with the increasing of meshing point velocity. When the velocity of meshing point exceeds 110 m/s, the increase became tardiness. As the load of meshing point increases, the value of minimal film thickness gently diminishes.

scholarly journals Dynamics of lubricated spiral bevel gears under different contact paths

Friction ◽  
2021 ◽  
Author(s):  
Wei Cao ◽  
Tao He ◽  
Wei Pu ◽  
Ke Xiao
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Transmission Efficiency ◽  
Friction Model ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Spiral Bevel ◽  
Meshing Characteristics ◽  
Assembly Error ◽  
Good Agreement

AbstractTo assess the meshing quality of spiral bevel gears, the static meshing characteristics are usually checked under different contact paths to simulate the deviation in the footprint from the design point to the heel or toe of the gear flank caused by the assembly error of two gear axes. However, the effect of the contact path on gear dynamics under lubricated conditions has not been reported. In addition, most studies regarding spiral bevel gears disregard the lubricated condition because of the complicated solutions of mixed elastohydrodynamic lubrication (EHL). Hence, an analytical friction model with a highly efficient solution, whose friction coefficient and film thickness predictions agree well with the results from a well-validated mixed EHL model for spiral bevel gears, is established in the present study to facilitate the study of the dynamics of lubricated spiral bevel gears. The obtained results reveal the significant effect of the contact path on the dynamic response and meshing efficiency of gear systems. Finally, a comparison of the numerical transmission efficiency under different contact paths with experimental measurements indicates good agreement.

Friction Model Using Full Elastohydrodynamic Lubrication for Spiral Bevel Gears

2017 ◽  
Author(s):  
Srikumar C. Gopalakrishnan ◽  
Yawen Wang ◽  
Teik C. Lim
Keyword(s):  
Coefficient Of Friction ◽  
Control Volume ◽  
Elastohydrodynamic Lubrication ◽  
Time Varying ◽  
Tooth Contact Analysis ◽  
Spiral Bevel Gears ◽  
Varying Coefficient ◽  
Bevel Gears ◽  
The Coefficient Of Friction ◽  
Spiral Bevel

Elastohydrodynamic lubrication phenomenon in spiral bevel gears was modeled in this study. The coefficient of friction calculated from the elastohydrodynamic (EHL) lubrication model is time varying. Friction is expected to have a greater impact on the spiral bevel gears than on any other right angled geared system due to the reversal of the contact area over a full tooth-to-tooth engagement cycle. The coefficient of friction formulated from an EHL model of spiral bevel gears depends upon lubricant properties, mesh forces and rotational speeds of the pinion and gear. Hence in this present study, a full elastohydrodynamic lubrication model was used to calculate the coefficient of friction in spiral bevel gears. The geometric and kinematic input data required for the EHL simulations were obtained from tooth contact analysis. Full numerical elastohydrodynamic lubrication simulations were carried out using the asymmetric integrated control volume (AICV) algorithm to compute the contact pressures and the coefficient of friction. The elastic deformations on the gear contact surfaces were calculated by circular convolution using a Fourier transform technique. The computed pressures, film thickness and the effective viscosity were used to calculate the time varying coefficient of friction for the spiral bevel gears. Parametric studies were conducted by varying the speed, torque applied, lubricant properties, temperature and slide to roll ratio to identify their impact on the time varying coefficient of friction.

A Model to Predict Pocketing Power Losses in Spiral Bevel Gears

2015 ◽  
Author(s):  
E. Erkilic ◽  
D. Talbot ◽  
A. Kahraman
Keyword(s):  
Power Losses ◽  
Spiral Bevel Gears ◽  
Gear Teeth ◽  
Bevel Gears ◽  
Gear Mesh ◽  
Simulation Procedure ◽  
Aerospace Applications ◽  
Face Width ◽  
Spiral Bevel ◽  
Lubrication Conditions

A computational methodology is proposed for prediction of power losses due to pocketing (pumping or squeezing) of oil at the mesh interface of spiral bevel gears. The model employs an existing cutting simulation procedure to define surface geometries of the gears through face-milling and face-hobbing processes. A novel hypoidal discretization method is proposed to define pocket volumes between meshing gear teeth along circumferential and face width directions. An existing fluid mechanics formulation, utilizing principles of conservation of mass, momentum and energy, is used to compute the load-independent (spin) power losses due to pocketing of the medium in the gear mesh interface. A simulation of aerospace applications is presented to highlight the effects of lubrication conditions, on pocketing power losses.

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