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.

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.

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.

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.

Evaluation of Spur Gear Pair on Tooth Root Bending Stress in Yawing Misalignment Contact Condition

2014 ◽  
Vol 980 ◽  
pp. 97-101 ◽  
Author(s):  
Mohd Rizal Lias ◽  
Mokhtar Awang ◽  
T.V.V.L.N. Rao ◽  
M. Fadhil
Keyword(s):  
Influence Factor ◽  
Spur Gear ◽  
Dynamics Simulation ◽  
Gear Pair ◽  
Tooth Root ◽  
Bending Stress ◽  
Time Dynamics ◽  
Gear Design ◽  
Face Width ◽  
Assembly Error

This paper evaluates the effects of yawing misalignment contact on the tooth root bending stress values of spur gear pair during the gear meshing cycle. A model basedon involute 3DparametricCAD geometry, of spur gear design ISO 6336:2006 is analyzed with worst loading position when yawing misalignment (Y) exist due to assembly error (AE) between 0.20 to 0.40 in degree scale values. Finite-element method (FEM) with dynamics module from ANSYS is used in order to calculate the tooth root bending stress (TRBS) at the critical region with respect to face width of pinion and gear section. A comparison is made between standard high point single tooth contactmodels (HPSTC) to this model as verification. Further analysis showeda good agreement that these methodologies are adequate in order to conduct a real time dynamics simulation to define the value of TRBS in Y condition due to AE. Yawingmisalignment influence factor (YMIF) was introduced as an indication of TRBS values in consideration of Y due to AEshows a higher result for pinion, give a good justification that the pinion is weaker compared to the gear in Y condition.

Effect of design parameters on stresses occurring at the tooth root in a spur gear pressed on a shaft

2021 ◽  
pp. 095440892199529
Author(s):  
Fatih Güven
Keyword(s):  
Internal Pressure ◽  
Tangential Stress ◽  
Spur Gear ◽  
Design Parameters ◽  
Interference Fit ◽  
Gear Design ◽  
Compact Design ◽  
Fit Tolerance ◽  
Moderate Stress ◽  
Good Agreement

Gears are commonly used in transmission systems to adjust velocity and torque. An integral gear or an interference fit could be used in a gearbox. Integral gears are mostly preferred as driving gear for a compact design to reduce the weight of the system. Interference fit makes the replacement of damaged gear possible and re-use of the shaft compared to the integral shaft. However, internal pressure occurs between mating surfaces of the components mated. This internal pressure affects the stress distribution at the root and bottom land of the gear. In this case, gear parameters should be re-considered to assure gear life while reducing the size of the gear. In this study, interference fitted gear-shaft assembly was examined numerically. The effects of rim thickness, profile shifting, module and fit tolerance on bending stress occurring at the root of the gear were investigated to optimize gear design parameters. Finite element models were in good agreement with analytical solutions. Results showed that the rim thickness of the gear is the main parameter in terms of tangential stress occurring at the bottom land of the gear. Positive profile shifting reduces the tangential stress while the pitch diameter of the gear remains constant. Also, lower tolerance class could be selected to moderate stress for small rim thickness.

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.

scholarly journals A Multiobjective Optimization Analysis of Spur Gear Pair: The Profile Shift Factor Effect on Structure Design and Efficiency

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Samya Belarhzal ◽  
Kaoutar Daoudi ◽  
El Mostapha Boudi ◽  
Aziz Bachir ◽  
Samira Elmoumen
Keyword(s):  
Multiobjective Optimization ◽  
Power Transmission ◽  
Spur Gear ◽  
Shift Factor ◽  
Structure Design ◽  
Operating Conditions ◽  
Gear Pair ◽  
Contact Ratio ◽  
Face Width ◽  
Volume Equation

Spur gears are an indispensable element of power transmission, most of the time used in small environments with severe operating conditions such as high temperature, vibrations, and humidity. For this reason, manufacturers and transmission designers are required to look for better gear designs and higher efficiency. In this paper, a multiobjective optimization was conducted, using genetic algorithms (GAs) for corrected spur gear pair with an objective to reduce the structure volume and transmission power loss and reveal the influence of the profile shift factor on the optimal structure fitness. The optimization variables included are the pinion and wheel profile shift factors in addition to the module, face width, and the number of pinion teeth mostly used in standard gear optimization. The profile shift factor influences the shape of the gear teeth, the contact ratio, and the load sharing. It affects then the optimal results meaningfully. The gear pair volume, center distance, and efficiency presented the objective functions while contact stress, bending stress, face with coefficient, and tooth tip interferences served as constraints. Furthermore, a volume equation was developed, in which a bottom clearance formula is included for more accurate results. "Multiobjective optimization" is conducted at medium and high speeds, and the results show that the structure design is compact compared to standard gears with reasonable efficiency for medium contact ratio.

Comparison of tooth profiles and oil formulation focusing lower power losses

2012 ◽  
Vol 226 (6) ◽  
pp. 529-540 ◽  
Author(s):  
Luís Magalhães ◽  
Ramiro Martins ◽  
Ivo Oliveira ◽  
Jorge Seabra
Keyword(s):  
Power Loss ◽  
Raw Materials ◽  
Helix Angle ◽  
Tooth Profile ◽  
Power Losses ◽  
Gear Teeth ◽  
Gear Design ◽  
Lubricant Formulation ◽  
Oil Formulation ◽  
Energetic Model

Environmental awareness, lower consumption of raw materials and longer life of equipment are main concerns nowadays and are leading to the research and development of lubricants and equipment to access those requirements. In this study, the power loss performance of three different tooth profile geometries, developed with the purpose of decreasing power losses while keeping the predicted life, were tested and evaluated in a FZG test rig. The path to reduce power losses was based on the decrease of the module, the increase of the helix angle and increase of the addendum modification coefficients in order to reduce the path of contact, i.e. the sliding velocity. The power loss behaviour of two different lubricants was also evaluated for each tooth profile geometry considered. The influence of the oil level in the gearbox was also evaluated. One of the lubricants has an ester base while the other has a polyalphaolefin base and both are fully formulated. An energetic model was developed for the FZG test gearbox and applied to these tests to improve the knowledge about the influence of tooth geometries as well as lubricant formulation in the power losses and coefficient of friction between gear teeth. The developed geometries showed that the path followed for the reduction of power losses produced the expected results and can be implemented with success on gear design.

Uncertainty Considerations in the Dynamics of Gear-Pair

2012 ◽  
Author(s):  
Fisseha M. Alemayehu ◽  
Stephen Ekwaro-Osire
Keyword(s):  
Parameter Uncertainty ◽  
Traditional Approach ◽  
Design Parameters ◽  
Dynamic Factor ◽  
Gear Pair ◽  
The Novel ◽  
Gear Design ◽  
Pair Model ◽  
Multibody Dynamic ◽  
Gear Systems

Gears and Gear systems are subjected to uncertainty of design parameters and loading caused by inherent conditions, measurement and manufacturing errors. Hence, the motivation of this work is to improve the deterministic design practice of gears and gear systems. A probabilistic rigid multibody dynamic gear-pair model with design and load uncertainties has been developed and analyzed. Rigid gear-pair model was developed in multibody dynamics software ADAMS and parameter uncertainty and probabilistic analysis was performed from separate probabilistic software called NESSUS. To perform the probabilistic multibody analysis, ADAMS and NESSUS were interfaced using MATLAB. The effect of parameter uncertainty on dynamic factor, DF of a gear pair was investigated. The sensitivity of DF to five uncertain loading and design parameters were also determined. This paper has demonstrated the importance of the novel PMBD modeling approach to gear design and dynamic factor analysis. The method has brought a new dimension of design approach of gears and gear systems than traditional approach that considers a certain empirically defined dynamic rating factors. In addition to revealing system reliability or under-performance through probability of failure, it also helps designers to consider certain variables critically through the sensitivity results.

Probabilistic Optimum Design of Compact Spur Gear Sets

1995 ◽  
Author(s):  
Chinyere Onwubiko ◽  
Landon Onyebueke ◽  
Feng C. Chen
Keyword(s):  
Optimum Design ◽  
Material Properties ◽  
Probabilistic Method ◽  
Spur Gear ◽  
Optimization Techniques ◽  
Design Parameters ◽  
Deterministic Method ◽  
Wide Range ◽  
Comparison Of The Results ◽  
Center Distance

Abstract Several methods have been proposed in the past for optimum design of spur gears. These methods have utilized deterministic design optimization techniques to obtain what could be considered satisfactory design parameters. At least two problems arise with the results of the deterministic approach; the inability to deal with uncertainties in material properties and over conservative design. On the other hand, probabilistic analysis methodology seeks to account for the uncertainties in material properties, loading conditions and disparate failure models. This paper discusses the application of probabilistic design methodology to the design of compact gear set. This is done by minimizing the gear center distance while constrained by the allowable surface pressure and bending stress. A comparison of the results of compact gear design using both deterministic and probabilistic methodologies is presented. The results indicate that deterministic method though satisfactory does not provide the designer enough information to make vast design decisions. The deterministic method provides only one value of the center distance while the probabilistic method provides the designer a range of choices. In fact, a designer is provided a wide range of design options depending on a desired level of reliability.

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