Experimental Investigations About the Power Loss Transition Between Churning and Windage for Spur Gears

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Romain Quiban ◽  
Christophe Changenet ◽  
Yann Marchesse ◽  
Fabrice Ville
Keyword(s):  
Power Loss ◽  
Spur Gear ◽  
Experimental Investigations ◽  
Spur Gears ◽  
Power Losses ◽  
Loss Model ◽  
Torque Measurements ◽  
Oil Immersion ◽  
Oil Jet ◽  
Very High

Abstract Oil sump lubrication is commonly used in gearboxes. When considering consistent speeds, oil immersion is usually set to low level in order to reduce associated power losses. This configuration is already used in some parts of helicopter mechanical transmissions, and it is under consideration as a lubrication solution for future electric powertrain where gearbox input speeds may be very high. The gear drag power losses are generally evaluated from either a churning power loss model for classic oil sump lubrication or a windage power loss model for oil jet lubrication. One may thus wonder how to estimate drag losses when considering a gear that only a small part is immersed. In this study, the authors investigate the transition between churning and windage phenomena for a spur gear. A series of torque measurements on a single spur gear rotating in an oil bath at numerous oil immersion levels have been carried out. Based on these results, a criterion to indicate which power loss model to use is proposed.

An Experimental Study of Influence of Lubrication Methods on Efficiency and Contact Fatigue Life of Spur Gears

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
J. Moss ◽  
A. Kahraman ◽  
C. Wink
Keyword(s):  
Experimental Study ◽  
Power Loss ◽  
Contact Fatigue ◽  
Spur Gear ◽  
Spur Gears ◽  
Power Losses ◽  
Contact Fatigue Life ◽  
The Impact ◽  
Jet Velocities ◽  
Lubrication Conditions

An experimental investigation of spur gear behavior was conducted with the aim of quantifying the impact of lubrication methods and conditions on the power losses and contact fatigue lives. Variations of dip and jet-lubrication are defined, and these behaviors were observed as a function of the lubrication conditions. Both types of measurements were performed using the same type of back-to-back test machines and the same spur gear test articles such that their evaluations can be correlated. Power loss experiments were performed under both loaded and unloaded conditions to determine both load-independent (spin) and load-dependent (mechanical) losses. Sets of long-cycle contact fatigue experiments were performed under the same lubrication conditions to determine macropitting lives in a statistically meaningful manner. Results indicate that the spin power losses are impacted by the lubrication method significantly while the mechanical losses are not influenced. Contact fatigue lives from jet-lubricated tests are comparable to those under dip-lubricated conditions ones as long as jet velocities are sufficient.

An Experimental Study of Influence of Lubrication Methods on Efficiency and Contact Fatigue Life of Spur Gears

2017 ◽  
Author(s):  
J. Moss ◽  
A. Kahraman ◽  
C. Wink
Keyword(s):  
Power Loss ◽  
Contact Fatigue ◽  
Spur Gear ◽  
Test Machine ◽  
Spur Gears ◽  
Power Losses ◽  
Contact Fatigue Life ◽  
The Impact ◽  
Jet Velocities ◽  
Lubrication Conditions

An experimental investigation of spur gear behavior was conducted with the aim of quantifying the impact of lubrication methods and conditions on the power losses and contact fatigue lives. Variations of dip and jet-lubrication were defined and these behaviors were observed as a function of the lubrication conditions. All measurements were performed using the same back-to-back test machine and the same spur gear test articles such that all evaluations were correlated. Power loss experiments were performed under both loaded and unloaded conditions to determine both load-independent (spin) and load-dependent (mechanical) losses. Sets of long-cycle contact fatigue experiments were performed under the same lubrication conditions to determine macro-pitting lives in a statistically meaningful manner. Results indicate that the spin power losses are impacted by the lubrication method significantly while the mechanical losses are not influenced. Contact fatigue lives from jet-lubricated tests are comparable to those under dip-lubricated conditions ones as long as jet velocities are sufficient.

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.

scholarly journals Study of Lubricant Jet Flow Phenomena in Spur Gears

1975 ◽  
Vol 97 (2) ◽  
pp. 283-288 ◽  
Author(s):  
L. S. Akin ◽  
J. J. Mross ◽  
D. P. Townsend
Keyword(s):  
Motion Picture ◽  
High Speed ◽  
Drop Size ◽  
Gear Tooth ◽  
Jet Flow ◽  
Spur Gear ◽  
Spur Gears ◽  
Gear Teeth ◽  
Flow Phenomena ◽  
Oil Jet

Lubricant jet flow impingement and penetration depth into a gear tooth space were measured at 4920 and 2560 using a 8.89-cm- (3.5-in.) pitch dia 8 pitch spur gear at oil pressures from 7 × 104 to 41 × 104 N/m2 (10 psi to 60 psi). A high speed motion picture camera was used with xenon and high speed stroboscopic lights to slow down and stop the motion of the oil jet so that the impingement depth could be determined. An analytical model was developed for the vectorial impingement depth and for the impingement depth with tooth space windage effects included. The windage effects on the oil jet were small for oil drop size greater than 0.0076 cm (0.003 in.). The analytical impingement depth compared favorably with experimental results above an oil jet pressure of 7 × 104 N/m2 (10 psi). Some of this oil jet penetrates further into the tooth space after impingement. Much of this post impingement oil is thrown out of the tooth space without further contacting the gear teeth.

scholarly journals Baseline Experimental Results on the Effect of Oil Temperature on Shrouded Meshed Spur Gear Windage Power Loss

2017 ◽  
Author(s):  
Irebert R. Delgado ◽  
Michael J. Hurrell
Keyword(s):  
Experimental Test ◽  
Power Loss ◽  
Spur Gear ◽  
Spur Gears ◽  
Test Results ◽  
Oil Viscosity ◽  
Gear Teeth ◽  
Temperature Load ◽  
Loss Efficiency

Rotorcraft gearbox efficiencies are reduced at increased surface speeds due to viscous and impingement drag on the gear teeth. This windage power loss can affect overall mission range, payload, and frequency of transmission maintenance. Experimental and analytical studies on shrouding for single gears have shown it to be potentially effective in mitigating windage power loss. Efficiency studies on unshrouded meshed gears have shown the effect of speed, oil viscosity, temperature, load, lubrication scheme, etc. on gear windage power loss. The open literature does not contain experimental test data on shrouded meshed spur gears. Gear windage power loss test results are presented on shrouded meshed spur gears at elevated oil inlet temperatures and constant oil pressure both with and without shrouding. Shroud effectiveness is compared at four oil inlet temperatures. The results are compared to the available literature and follow-up work is outlined.

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.

scholarly journals A windage power loss model based on CFD study about the volumetric flow rate expelled by spur gears

2012 ◽  
Vol 13 (5) ◽  
pp. 317-323 ◽  
Author(s):  
Sylvain Pallas ◽  
Yann Marchesse ◽  
Christophe Changenet ◽  
Fabrice Ville ◽  
Philippe Velex
Keyword(s):  
Flow Rate ◽  
Power Loss ◽  
Volumetric Flow Rate ◽  
Spur Gears ◽  
Loss Model ◽  
Model Based

Experimental and Numerical Simulation Study of Simultaneous Toothing of Spur Gears by Press-Rolling Process

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Liviu Nistor ◽  
Adriana Neag ◽  
Ionut Marian ◽  
Dan Frunza
Keyword(s):  
Numerical Simulation ◽  
Continuous Flow ◽  
Spur Gear ◽  
Rolling Process ◽  
Experimental Investigations ◽  
Spur Gears ◽  
Element Analysis ◽  
3D Finite Element ◽  
Gear Geometry ◽  
Experimental Trials

In this paper, the cold simultaneous toothing of spur gears has been investigated. This method can be described as a press-rolling process. The influence of gear geometry such as teeth number and the deformation mechanism was investigated by 3D finite-element analysis using forge® software in terms of teeth forming and forming loads evolution. Based on these simulations, the experimental investigations were carried out to obtain a spur gear form with the good quality, using several billet dimensions. The experimental trials and simulations conducted for the spur gear (z = 23 teeth and m = 1.5 mm) showed premises to continuous flow lines formation at the base of the teeth. The maximum pressing force results from the numerical simulation agree with the experimental maximum force recorded.

Instantaneous Behavior of Lubricating Oil Supplied onto the Tooth Flanks and Its Influence on the Scoring Resistance of Spur Gears

1976 ◽  
Vol 98 (2) ◽  
pp. 635-641 ◽  
Author(s):  
K. Fujita ◽  
F. Obata ◽  
K. Matsuo
Keyword(s):  
Spur Gear ◽  
Lubricating Oil ◽  
Spur Gears ◽  
Gear Pair ◽  
Oil Supply ◽  
Nozzle Position ◽  
Jet Velocity ◽  
Oil Jet ◽  
Scoring Resistance

The correlation between the oil supply conditions, such as oil jet velocity, oil-nozzle position and its direction, and the scoring resistance of spur gear pair has been studied. The influence of the oil supply conditions on the instantaneous behaviors of the lubricating oil supplied onto the tooth flanks were brought to light by stroboscopic photographs. The scoring resistance was greatly affected by the oil supply conditions and the reasons were clarified by considering the instantaneous behaviors of lubricating oil. In order to have high scoring resistance, oil must be supplied over the whole working flank.

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