A Helical Gear Pair Pocketing Power Loss Model

2014 ◽  
Vol 136 (2) ◽  
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 a 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 the fluid pressure and velocity distributions in time along with the pocketing power loss as a function of the speed, helix angle, and oil-to-air ratio.

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.

Effect of Axial Vibrations on the Dynamics of a Helical Gear Pair

1993 ◽  
Vol 115 (1) ◽  
pp. 33-39 ◽  
Author(s):  
A. Kahraman
Keyword(s):  
Natural Frequencies ◽  
Helix Angle ◽  
Transmission Error ◽  
Helical Gear ◽  
Forced Response ◽  
Dynamic Mesh ◽  
Gear Pair ◽  
Gear Mesh ◽  
Static Transmission Error ◽  
Helical Gear Pair

In this paper, a linear dynamic model of a helical gear pair has been developed. The model accounts for the shaft and bearing flexibilities, and the dynamic coupling among the transverse, torsional, axial and rotational (rocking) motions due to the gear mesh. The natural frequencies and the mode shapes have been predicted, and the modes which are excited by the static transmission error have been identified. The forced response due to the static transmission error has also been predicted, including the dynamic mesh and bearing forces. A parametric study has been performed to investigate the effect of the helix angle on the free and forced vibrational characteristics of the gear pair. It has been shown that the helix angle can be neglected in predicting the natural frequencies and the dynamic mesh forces. An accurate prediction of dynamic bearing forces and moments requires inclusion of the helix angle in the analysis.

Effect of Axial Vibrations on the Dynamics of a Helical Gear Pair

1991 ◽  
Author(s):  
Ahmet Kahraman
Keyword(s):  
Natural Frequencies ◽  
Helix Angle ◽  
Transmission Error ◽  
Helical Gear ◽  
Forced Response ◽  
Dynamic Mesh ◽  
Gear Pair ◽  
Gear Mesh ◽  
Static Transmission Error ◽  
Helical Gear Pair

Abstract In this paper, a linear dynamic model of a helical gear pair has. been developed. The model accounts for the shaft and bearing flexibilities, and the dynamic coupling among the transverse, torsional, axial and rotational motions because of the gear mesh. The natural frequencies and the mode shapes have been predicted, and the modes which are excited by the static transmission error have been identified. The forced response due to the static transmission error has also been predicted, including the dynamic mesh and bearing forces. A parametric study has been performed to investigate the effect of the helix angle on the free and forced vibrational characteristics of the gear pair. It has been shown that the helix angle can be neglected in predicting the natural frequencies and the dynamic mesh forces. An accurate prediction of dynamic bearing forces and moments requires inclusion of helix angle in the analysis.

Utilization of Tooth Contact Pattern in a Gear Meshing Model for Estimation of Sliding Loss in a Parallel-Axis Gear Pair

2014 ◽  
Vol 619 ◽  
pp. 68-72
Author(s):  
Jetsada Phraeknanthoe ◽  
Natcha Ponchai ◽  
Chanat Ratanasumawong
Keyword(s):  
Helix Angle ◽  
Helical Gear ◽  
Experimental Results ◽  
Gear Pair ◽  
Contact Pattern ◽  
Tooth Contact ◽  
Parallel Axis ◽  
Helical Gear Pair

The utilization of tooth contact pattern in a gear meshing model for estimation of sliding loss in a spur and helical gear pair is presented in this paper. The photo of tooth contact pattern taken after the gear operation is used as the database to generate the simplified tooth contact pattern. Then the simplified contact pattern is used along with the gear meshing model to estimate the sliding loss of a gear pair. Experiments are done to verify the results. The estimated results from the presented method agree well with the experimental results. The presented method is able to estimate the effect of the helix angle on the sliding loss correctly whereas the estimation without using the data of tooth contact pattern cannot.

scholarly journals Time-varying dynamic analysis for a helical gear pair system with three-dimensional motion due to bearing deformation

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402091812
Author(s):  
Ying-Chung Chen
Keyword(s):  
Three Dimensional ◽  
Helix Angle ◽  
Helical Gear ◽  
Dynamic Responses ◽  
Time Varying ◽  
Gear Pair ◽  
Contact Ratio ◽  
Transverse Pressure ◽  
Helical Gear Pair ◽  
Center Distance

The dynamic response of a helical gear pair system is investigated. A new dynamic model for a helical gear pair system, considering three-dimensional motion due to bearing deformation, is proposed. The proposed model considers the helix angle, gear pair center distance, transverse pressure angle, and the contact ratio as time-dependent variables, which are considered as constants in other models. In fact, three-dimensional motion due to bearing deformation will lead to the changes in a series of dynamic responses. The system equations of motion were obtained by applying Lagrange’s equation and the dynamic responses are computed by the fourth-order Runge–Kutta method. The time-varying dynamic displacements, helix angle, gear pair center distance, transverse pressure angle, and the contact ratio are investigated with bearing deformation, different radial bear stiffness, different axial bear stiffness, and gear eccentricity. The results show that, due to the time-varying effect, this new helical gear pair model provides more accurate dynamic responses than those previous models which are considered as constant. In the future, this study can provide some useful information for the time-varying dynamic design of a helical gear pair system.

Analysis of mechanical power loss of a helical gear pair based on the starved thermal-elastohydrodynamic lubrication model

2019 ◽  
Vol 72 (3) ◽  
pp. 333-340
Author(s):  
Mingyong Liu ◽  
Peidong Xu ◽  
Jinxi Zhang ◽  
Huafeng Ding
Keyword(s):  
Surface Roughness ◽  
Tribological Properties ◽  
Power Loss ◽  
Elastohydrodynamic Lubrication ◽  
Helical Gear ◽  
Mechanical Power ◽  
Gear Pair ◽  
Content Type ◽  
Helical Gear Pair ◽  
Film Lubrication

Purpose Power loss is an important index to evaluate the transmission performance of a gear pair. In some cases, the starved lubrication exists on the gear contact interface. The purpose of this paper is to reveal the mechanical power loss of a helical gear pair under starved lubrication. Design/methodology/approach A starved thermal-elastohydrodynamic lubrication (EHL) model is proposed to evaluate the tribological properties of a helical gear pair. The numerical result has been validated against the published simulation data. Based on the proposed model, the influence of thermal effect, working conditions, inlet oil-supply layer and surface roughness on the mechanical power loss and lubrication performance has been discussed. Findings Results show that the thermal effect has a significant effect on the tribological properties of helical gear pair, especially on mechanical power loss. For a specified working condition, there is an optimal oil supply for gear lubrication to obtain the state of full film lubrication. Meanwhile, it reveals that the mechanical power loss increases with the increase of the surface roughness amplitude. Originality/value In this paper, a starved thermal-EHL model has been developed for the helical gear pair based on the finite line contact theory. This model can be used to analyze the tribological properties of gear pair from full film lubrication to mixed lubrication. The results can provide the tribological guidance for design of a helical gear pair.

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.

Parametric Studies of Mechanical Power Loss for Helical Gear Pair Using a Thermal Elastohydrodynamic Lubrication Model

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Mingyong Liu ◽  
Peidong Xu ◽  
Chunai Yan
Keyword(s):  
Friction Coefficient ◽  
Thermal Effect ◽  
Power Loss ◽  
Elastohydrodynamic Lubrication ◽  
Mechanical Efficiency ◽  
Helical Gear ◽  
Tribological Performance ◽  
Mechanical Power ◽  
Gear Pair ◽  
Helical Gear Pair

In this study, a comprehensive mechanical efficiency model based on the thermal elastohydrodynamic lubrication (TEHL) is developed for a helical gear pair. The tribological performance of the helical gear pair is evaluated in terms of the average film thickness, friction coefficient, mechanical power loss, mechanical efficiency, etc. The influence of basic design parameters, working conditions, thermal effect, and surface roughness are studied under various transmission ratios. Results show that the contribution of thermal effect on the tribological performance is remarkable. Meanwhile, the rolling power loss constitutes an important portion of the total mechanical power loss, especially around the meshing position where the pitch point is located in the middle of contact line and the full elastohydrodynamic lubrication (EHL) state with the friction coefficient less than 0.005. The proper increase of normal pressure angle and number of tooth can improve the tribological performance. The influence of helix angle on the mechanical efficiency is less significant. A positive addendum modification coefficient for pinion and a negative addendum modification coefficient for wheel are good for improving the mechanical efficiency. The results provide the tribological guidance for design of a helical gear pair in engineering.

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