Load-Independent Spin Power Losses of a Spur Gear Pair: Model Formulation

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
S. Seetharaman ◽  
A. Kahraman
Keyword(s):  
Power Loss ◽  
Spur Gear ◽  
Companion Paper ◽  
Total Spin ◽  
Operating Conditions ◽  
Gear Pair ◽  
Power Losses ◽  
Gear Mesh ◽  
Drag Forces ◽  
Mechanics Model

A physics-based fluid mechanics model is proposed to predict spin power losses of gear pairs due to oil churning and windage. While the model is intended to simulate oil churning losses in dip-lubricated conditions, certain components of it apply to air windage losses as well. The total spin power loss is defined as the sum of (i) power losses associated with the interactions of individual gears with the fluid, and (ii) power losses due to pumping of the oil at the gear mesh. The power losses in the first group are modeled through individual formulations for drag forces induced by the fluid on a rotating gear body along its periphery and faces, as well as for eddies formed in the cavities between adjacent teeth. Gear mesh pumping losses will be predicted analytically as the power loss due to squeezing of the lubricant, as a consequence of volume contraction of the mesh space between mating gears as they rotate. The model is applied to a unity-ratio spur gear pair to quantify the individual contributions of each power loss component to the total spin power loss. The influence of operating conditions, gear geometry parameters, and lubricant properties on spin power loss are also quantified at the end. A companion paper (Seetharaman et al., 2009, “Oil Churning Power Losses of a Gear Pair: Experiments and Model Validation,” ASME J. Tribol., 131, p. 022202) provides comparisons to experiments for validation of the proposed model.

Oil Churning Power Losses of a Gear Pair: Experiments and Model Validation

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
S. Seetharaman ◽  
A. Kahraman ◽  
M. D. Moorhead ◽  
T. T. Petry-Johnson
Keyword(s):  
Power Loss ◽  
Spur Gear ◽  
Companion Paper ◽  
Design Parameters ◽  
Measured Parameter ◽  
Gear Pair ◽  
Power Losses ◽  
Gear Design ◽  
Face Width ◽  
Wide Range

This paper presents the results of an experimental study on load-independent (spin) power losses of spur gear pairs operating under dip-lubricated conditions. The experiments were performed over a wide range of operating speed, temperature, oil levels, and key gear design parameters to quantify their influence on spin power losses. The measurements indicate that the static oil level, rotational speed, and face width of gears have a significant impact on spin power losses compared with other parameters such as oil temperature, gear module, and the direction of gear rotation. A physics-based gear pair spin power loss formulation that was proposed in a companion paper (Seetharaman and Kahraman, 2009, “Load-Independent Spin Power Losses of a Spur Gear Pair: Model Formulation,” ASME J. Tribol., 131, p. 022201) was used to simulate these experiments. Direct comparisons between the model predictions and measurements are provided at the end to demonstrate that the model is capable of predicting the measured spin power loss values as well as the measured parameter sensitivities reasonably well.

An Experimental Methodology to Determine Components of Power Losses of a Gearbox

2021 ◽  
Vol 143 (11) ◽  
Author(s):  
A. Dindar ◽  
K. Chaudhury ◽  
I. Hong ◽  
A. Kahraman ◽  
C. Wink
Keyword(s):  
Power Loss ◽  
Spur Gear ◽  
Rolling Element Bearing ◽  
Experimental Methodology ◽  
Total Power ◽  
Gear Pair ◽  
Rolling Element Bearings ◽  
Power Losses ◽  
Rolling Element ◽  
The One

Abstract In this study, an experimental methodology is presented to separate various components of the power loss of a gearbox. The methodology relies on two separate measurements. One is designed to measure total power loss of a gearbox housing a single spur gear pair under both loaded and unloaded conditions such that load-independent (spin) and load-dependent (mechanical) components can be separated. With the assumption that gear pair and rolling element bearings constitute the bulk of the gearbox power loss, a second measurement system designed to quantify rolling element bearing losses is proposed. With this setup, spin and mechanical power losses of rolling element bearings used in the gearbox experiments are measured. Combining the sets of gearbox and bearing data, power loss components attributable to the gear pair and rolling element bearings are quantified as a function of speed and torque. The results indicate that all gear and bearing related components are significant and a methodology such as the one proposed in this study is warranted.

Frictional dynamic model predictions of FZG-A10 spur gear pairs considering profile errors

2020 ◽  
pp. 135065012096297
Author(s):  
Nabih Feki ◽  
Maroua Hammami ◽  
Olfa Ksentini ◽  
Mohamed Slim Abbes ◽  
Mohamed Haddar
Keyword(s):  
Dynamic Model ◽  
Coefficient Of Friction ◽  
Power Loss ◽  
Spur Gear ◽  
Operating Conditions ◽  
Time Dependent ◽  
Nonlinear Dynamic Model ◽  
Gear Mesh ◽  
Proposed Model ◽  
Profile Errors

In this work, a nonlinear dynamic model of an FZG-A10 spur gear was investigated by taking into account for the actual time-varying gear mesh stiffness and the frictional effects between meshing gear teeth to evaluate the influence of the dynamic effects on frictional gear power loss predictions. The equations of motion of the generalized translational-torsional coupled dynamic system derived from Lagrange principle was extended compared to authors’ previous work in order to account for time dependent coefficient of friction and profile errors. The dynamic response of spur gears, computed by an iterative implicit scheme of Newmark, is changed due to the presence of coefficient of friction and profile errors. A dynamic analysis was performed and the influence of frictional effect including tooth shape deviations, in particular, was scrutinized since a time-dependent coefficient of friction is deeply related to the gear surface roughness and all parameters dependent on gears error profiles are introduced in the proposed model. The predicted meshing gear power losses with constant and local friction coefficient were compared. The influence of constant and variable profile errors considered in the local coefficient of friction formulation was also studied and their corresponding root mean square (RMS) power loss was compared to the experimental results. The results using FZG A10 spur gear pairs running under several operating conditions (different loads and speeds) validate the superiority of the proposed model against previous similar models.

Analysis of the Oil Squeezing Power Losses of a Spur Gear Pair by Mean of CFD Simulations

2012 ◽  
Author(s):  
Franco Concli ◽  
Carlo Gorla
Keyword(s):  
High Efficiency ◽  
Fluid Dynamic ◽  
Axial Direction ◽  
Spur Gear ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Main Concern ◽  
Power Losses ◽  
Dynamic Simulations ◽  
Gear Mesh

Efficiency is becoming more and more a main concern in the design of power transmissions and the demand for high efficiency gearboxes is continuously increasing. Also the new restrictive euro standards for the reduction of pollutant emissions from light vehicles impose to improve the efficiency of the engines but also of the gear transmissions. For this reason the resources dedicated to this goal are continuously increasing. The first step to improve efficiency is to have appropriate models to compare different design solutions. Even if the efficiency of transmissions is quit high if compared to the efficiency of the engines and appropriate models to predict the power losses due to gear meshing, to bearings and to seals already exist, in order to have a further improvement, some aspects like the power losses related to the oil churning, oil squeezing and windage are still to be investigated. These losses rise from the interaction between the moving or rotating elements of the transmission and the lubricant. In previous papers [39, 40, 41 43, 44], the authors have investigated the churning losses of planetary speed reducers (in which there is a relative motion between the “planets + planet carrier” and the lubricant). This report is focused on the oil squeezing power losses. This kind of losses is associated with the pumping of the oil at the gear mesh, where there is a contraction of the volume between the mating gears due to the rotation of them and a consequent overpressure. This overpressure implies a fluid flow primarily in the axial direction and this, for viscous fluids, means additional power losses and a decrease of the efficiency. In this work this phenomena has been studied by means of some CFD (computational fluid dynamic) simulations with a VOF (volume of fluid) approach. The influence of some operating conditions like the rotational speed and the lubricant temperature have been studied. The results of this study have been included in a model to predict the efficiency of the whole transmission.

A Computational Study on the Mechanical Power Loss of a Spur Gear Pair Under the Thermal Tribo-Dynamic Condition

2015 ◽  
Author(s):  
Sheng Li
Keyword(s):  
Power Loss ◽  
Computational Study ◽  
Dynamic Condition ◽  
Elastohydrodynamic Lubrication ◽  
Static Condition ◽  
Spur Gear ◽  
Mechanical Power ◽  
Gear Pair ◽  
Gear Mesh ◽  
Six Degree Of Freedom

This study proposes a formulation for the description of the gear mesh mechanical power loss under the thermal tribodynamic condition. A six degree-of-freedom motion equation set that models the vibratory motions of a general spur gear pair is coupled with the governing equations for the description of the gear thermal mixed elastohydrodynamic lubrication to include the interactions between the gear dynamics and gear tribology disciplines in the modeling of the gear mesh mechanical power loss. The important role of the gear thermal tribo-dynamics in power loss is demonstrated by comparing the predictions of the proposed model to those under the thermal quasi-static condition, and the iso-thermal tribo-dynamic condition, respectively.

scholarly journals An Experimental Investigation of Churning Power Losses of a Gearbox

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
J. Polly ◽  
D. Talbot ◽  
A. Kahraman ◽  
A. Singh ◽  
H. Xu
Keyword(s):  
Helical Gear ◽  
Operating Conditions ◽  
Gear Pair ◽  
Power Losses ◽  
Helical Gears ◽  
Gear Mesh ◽  
System A ◽  
Final Drive ◽  
Helical Gear Pair ◽  
Lubrication Conditions

In this study, load-independent (spin) power losses of a gearbox operating under dip-lubrication conditions are investigated experimentally using a final-drive helical gear pair from an automotive transmission as the example system. A dedicated gearbox is developed to operate a single gear or a gear pair under given speed and temperature conditions. A test matrix that consists of sets of tests with: (i) a single spur, helical gears, or disks with no teeth and (ii) helical gear pairs is executed at various temperatures, immersion depths, and pinion positions relative to its mating gear. Power losses from single gear and gear pair at identical operating conditions are compared to quantify the components of the total spin loss in the form of losses due to gear drag, gear mesh pocketing, and bearings and seals.

scholarly journals An Experimental Investigation of Churning Power Losses of a Gearbox

2017 ◽  
Author(s):  
J. Polly ◽  
David Talbot ◽  
Ahmet Kahraman ◽  
Avinash Singh ◽  
Hai Xu
Keyword(s):  
Helical Gear ◽  
Operating Conditions ◽  
Gear Pair ◽  
Power Losses ◽  
Gear Mesh ◽  
System A ◽  
Automotive Transmission ◽  
Final Drive ◽  
Helical Gear Pair ◽  
Lubrication Conditions

In this study, load-independent (spin) power losses of a gearbox operating under dip-lubrication conditions are investigated experimentally using a final-drive helical gear pair from an automotive transmission as the example system. A dedicated gearbox is developed to operate a single gear or a gear pair under given speed and temperature conditions. A test matrix that consists of sets of tests with (i) single gears (spur, helical, or representative disks with no teeth), and (ii) helical gear pairs is executed at various temperatures, immersion depths and pinion positions relative to its mating gear. Power losses from single gears and gear pairs at identical operating conditions are compared to quantify the components of the total spin loss in the form of losses due to gear drag, gear mesh pocketing, and bearings and seals.

Effect of Design Parameters on Lubrication Behavior of Spur Gear Pairs

2017 ◽  
Author(s):  
Yanfang Liu ◽  
Qiang Liu ◽  
Peng Dong
Keyword(s):  
Power Loss ◽  
Elastohydrodynamic Lubrication ◽  
Spur Gear ◽  
Design Parameters ◽  
Curvature Radius ◽  
Gear Pair ◽  
Sliding Velocity ◽  
Rolling Velocity ◽  
Lubrication Performance ◽  
Meshing Process

An involute spur gear pair meshing model is firstly provided in this study to achieve relevant data such as rolling velocity, sliding velocity, curvature radius etc. These data are needed in a transient, Newtonian elastohydrodynamic lubrication (EHL) model which is provided later. Based on these two models, the behavior of an engaged spur gear pair during the meshing process is investigated under dynamic conditions, film thickness, pressure, friction coefficient etc. could be achieved through the models. Then, power loss under certain operating condition is calculated. Relationship between power loss and lubrication performance is also analyzed.

On Rolling Resistance in Gear Transmission

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
S. S. Ghosh ◽  
G. Chakraborty
Keyword(s):  
Experimental Data ◽  
Friction Force ◽  
Contact Force ◽  
Power Loss ◽  
Degrees Of Freedom ◽  
Rolling Resistance ◽  
Spur Gear ◽  
Gear Transmission ◽  
Gear Pair ◽  
Six Degrees Of Freedom

The effect of rolling resistance on the power loss during gear transmission has been studied. The resistance has been modeled by a lateral shift of the line of action of the contact force. The effect of this shift on the equivalent friction force has been predicted with the help of a six degrees of freedom (DOF) model of a spur gear pair. The predicted results agree closely with the experimental data available in literature.

A Helical Gear Pair Pocketing Power Loss Model

2013 ◽  
Author(s):  
David Talbot ◽  
Ahmet Kahraman ◽  
Satya Seetharaman
Keyword(s):  
Fluid Dynamics ◽  
Power Loss ◽  
Control Volume ◽  
Fluid Pressure ◽  
Helix Angle ◽  
Helical Gear ◽  
Gear Pair ◽  
Dynamics Model ◽  
Gear Mesh ◽  
Helical Gear Pair

A new fluid dynamics model is proposed to predict the power losses due to pocketing of air, oil, or an air-oil mixture in the helical gear meshes. The proposed computational procedure treats a helical gear pair as combination of a number of narrow face width spur gear segments staggered according to the helix angle and forms a discrete, fluid dynamics model of the medium being pocketed in the gear mesh. Continuity and conservation of momentum equations are applied to each coupled control volume filled with a compressible fluid mixture to predict fluid pressure and velocity distributions from, which the instantaneous pocketing power loss is calculated. The proposed model is exercised in order to investigate fluid pressure and velocity distributions in time, as well as pocketing power loss as a function of speed, helix angle and oil-to-air ratio.

Sign in / Sign up

Export Citation Format

Share Document