Effect of Surface Finish on Gear Tooth Friction

1999 ◽  
Vol 122 (1) ◽  
pp. 354-360 ◽  
Author(s):  
R. D. Britton ◽  
C. D. Elcoate ◽  
M. P. Alanou ◽  
H. P. Evans ◽  
R. W. Snidle
Keyword(s):  
Surface Finish ◽  
Gear Tooth ◽  
Elastohydrodynamic Lubrication ◽  
Engine Oil ◽  
Tooth Surface ◽  
Engineering Practice ◽  
Turbine Engine ◽  
Frictional Losses ◽  
Friction Measurements ◽  
Effect Of Surface

A special four-gear rig has been used to determine gear tooth frictional losses at loads and speeds representative of engineering practice using a gas-turbine engine oil. The effect of surface finish has been investigated by comparing the frictional losses of conventionally ground teeth (with roughness average, Ra, of approximately 0.4 μm) with those of teeth which were superfinished to approximately 0.05 μm Ra. It was found that superfinishing resulted in a reduction of friction of typically 30 percent with correspondingly lower tooth surface temperatures under the same conditions of load and speed. Film generation and frictional traction in the experiments were simulated theoretically using a thin film non-Newtonian micro-elastohydrodynamic lubrication solver, and encouraging agreement between friction measurements and theoretical predictions was obtained. [S0742-4787(00)04701-9]

Conditions for Scuffing Failure of Ground and Superfinished Steel Disks at High Sliding Speeds Using a Gas Turbine Engine Oil

1995 ◽  
Vol 117 (3) ◽  
pp. 482-489 ◽  
Author(s):  
M. J. Patching ◽  
C. C. Kweh ◽  
H. P. Evans ◽  
R. W. Snidle
Keyword(s):  
Experimental Investigation ◽  
Gas Turbine ◽  
Surface Finish ◽  
Axial Direction ◽  
Gas Turbine Engine ◽  
Hardened Steel ◽  
Engine Oil ◽  
Turbine Engine ◽  
Involute Gears ◽  
Scuffing Failure

This paper describes the results of an experimental investigation to compare the scuffing performance of conventionally ground and superfinished hardened steel disks operating at sliding speeds of up to 26 m/s and lubricated with a gas turbine engine oil at a temperature of 100° C. The ground disks were finished in the axial direction to simulate the orientation of surface finish found on involute gears. Superfinishing was found to give a significant increase in the load at which scuffing occurred. Frictional traction was also measured in the experiments and was found to be significantly lower for the superfinished disks in the loading stages preceding scuffing failure.

Study on Design Method of the Double Arc Gear Hobs

2013 ◽  
Vol 823 ◽  
pp. 257-260
Author(s):  
Jie Wu ◽  
Jia Quan Wang
Keyword(s):  
Design Method ◽  
Gear Tooth ◽  
Tooth Profile ◽  
Tooth Surface ◽  
Engineering Practice ◽  
Approximate Design ◽  
Circular Arc ◽  
Running Performance ◽  
Engagement Theory ◽  
Gear Rack

This article find that one of the effecting the double circular arc gear s running performance is the double circular arc gear tooth profile precision, through analysis to the running-in properties of double arc gear. The problems about tooth profile precision of gear hobs caused by the current profiling theory and approximate design method of gear hobs are analyzed. In the design of circular arc gear hob, use the space engagement theory, can eliminating the tooth error. Acquiring the equation of hobs basic of worm tooth surface by analytical and calculation that the establishment of basic gear rack and worm of hob meshing. The hob not only eliminate the tooth profile error in manufacturing, but also improve the running performance of double circular arc gear, and provides the theory evidence for engineering practice.

Tribological Information for Designers: Some Observations on the Proceedings of the International Conference on Lubrication and Wear Held at the Institution of Mechanical Engineers in September 1967

1967 ◽  
Vol 182 (14) ◽  
pp. 227-238
Author(s):  
F. T. Barwell
Keyword(s):  
Surface Finish ◽  
Digital Computer ◽  
Elastohydrodynamic Lubrication ◽  
Journal Bearings ◽  
Sufficient Information ◽  
Transient Load ◽  
Extended Range ◽  
Correct Application ◽  
Fundamental Equations ◽  
Effect Of Surface

A series of comprehensive reviews reveals much useful information that has become available during the last ten years and which enables the design of bearings to be placed on a sounder basis. The extended range and utilization of the digital computer has facilitated the solution of both the fundamental equations of lubrication and the optimization of design. Sufficient information now exists to solve the problem of correct application of journal bearings under conditions of turbulence, transient load, and instability. Gas bearings are being used extensively and the design and stabilization of externally pressurized bearings are described. The theory of elastohydrodynamic lubrication has proved revealing in the design of cams and has provided understanding of the effect of surface finish on endurance under pitting fatigue conditions.

Analysis of Micro-Elastohydrodynamic Lubrication and Prediction of Surface Fatigue Damage in Micropitting Tests on Helical Gears

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
H. P. Evans ◽  
R. W. Snidle ◽  
K. J. Sharif ◽  
B. A. Shaw ◽  
J. Zhang
Keyword(s):  
Damage Accumulation ◽  
Gear Tooth ◽  
Contact Fatigue ◽  
Elastohydrodynamic Lubrication ◽  
Tooth Surface ◽  
Asperity Contact ◽  
Surface Fatigue ◽  
Tooth Surfaces ◽  
Surface Profiles ◽  
Alternative Processes

The paper describes results obtained from the micro-elastohydrodynamic lubrication (micro-EHL) modeling of the gear tooth contacts used in micropitting tests together with a contact fatigue and damage accumulation analysis of the surfaces involved. Tooth surface profiles were acquired from pairs of helical test gears and micro-EHL simulations were performed corresponding to surfaces that actually came into contact during the meshing cycle. Plane strain fatigue and damage accumulation analysis shows that the predicted damage is concentrated close to the tooth surfaces and this supports the view that micropitting arises from fatigue at the asperity contact level. A comparison of the micropitting performance of gears finish-ground by two alternative processes (generation-grinding and form-grinding) suggests that 3D “waviness” may be an important factor in explaining their different micropitting behavior.

Analysis of Micro-Elastohydrodynamic Lubrication and Surface Fatigue in Gear Micropitting Tests

2011 ◽  
Author(s):  
H. P. Evans ◽  
R. W. Snidle ◽  
K. J. Sharif
Keyword(s):  
Damage Accumulation ◽  
Gear Tooth ◽  
Contact Fatigue ◽  
Elastohydrodynamic Lubrication ◽  
Tooth Surface ◽  
Asperity Contact ◽  
Cycle Fatigue ◽  
Surface Fatigue ◽  
Tooth Surfaces ◽  
Surface Profiles

The paper describes results obtained from the micro-elastohydrodynamic lubrication (micro-EHL) modelling of the gear tooth contacts used in micropitting tests together with contact fatigue and damage accumulation analysis of the surfaces involved. Tooth surface profiles were acquired from pairs of helical test gears and micro-EHL simulations were performed corresponding to surfaces that actually came into contact during the meshing cycle. Fatigue and damage accumulation analysis shows that predicted damage is concentrated close to the tooth surfaces and this strongly suggests that micropitting damage arises from fatigue at the asperity contact level.

Effect of Impact Load on Transient Elastohydrodynamic Lubrication of Spur Gears

2011 ◽  
Vol 317-319 ◽  
pp. 548-551
Author(s):  
You Qiang Wang ◽  
Zhi Cheng He
Keyword(s):  
Film Thickness ◽  
Impact Load ◽  
Gear Tooth ◽  
Elastohydrodynamic Lubrication ◽  
Tooth Surface ◽  
Maximum Pressure ◽  
Spur Gears ◽  
Load Spectrum ◽  
Minimum Film Thickness ◽  
The Impact

A full transient elastohydrodynamic lubrication(EHL) solution of involute spur gears is obtained under impact load based on the multi-grid (MG) method for solving the pressures, the multi-level multi-integration (MLMI) approach for evaluating the elastic deformations, which takes into account the variation of equivalent curvature , entertainment velocity and load on time along the line of action, the gear tooth surface is assumed to be smooth. The influences of impact load spectrum and the approach impact load when the teeth come into action on the EHL pressure and film thickness are analyzed in the paper. The results show that the approach impact load can strongly influence the approach point maximum pressure and minimum film thickness. The impact load can lead to instantaneous lubrication film deterioration between contact teeth of involute spur gears. The maximum pressure and the minimum film thickness all occur in the vicinity of approach point immediately after the impact load was feed. The approach impact load is seriously harmful to the gear lubrication.

Modeling of surface roughness in a novel magnetorheological gear profile finishing process

2020 ◽  
pp. 095440622097826
Author(s):  
Ravi Datt Yadav ◽  
Anant Kumar Singh ◽  
Kunal Arora
Keyword(s):  
Surface Roughness ◽  
Gear Tooth ◽  
Surface Characteristics ◽  
Spur Gear ◽  
Tooth Profile ◽  
Tooth Surface ◽  
Magnetic Flux Density ◽  
Element Analysis ◽  
Finishing Process ◽  
Gear Profile

Fine finishing of spur gears reduces the vibrations and noise and upsurges the service life of two mating gears. A new magnetorheological gear profile finishing (MRGPF) process is utilized for the fine finishing of spur gear teeth profile surfaces. In the present study, the development of a theoretical mathematical model for the prediction of change in surface roughness during the MRGPF process is done. The present MRGPF is a controllable process with the magnitude of the magnetic field, therefore, the effect of magnetic flux density (MFD) on the gear tooth profile has been analyzed using an analytical approach. Theoretically calculated MFD is validated experimentally and with the finite element analysis. To understand the finishing process mechanism, the different forces acting on the gear surface has been investigated. For the validation of the present roughness model, three sets of finishing cycle experimentations have been performed on the spur gear profile by the MRGPF process. The surface roughness of the spur gear tooth surface after experimentation was measured using Mitutoyo SJ-400 surftest and is equated with the values of theoretically calculated surface roughness. The results show the close agreement which ranges from −7.69% to 2.85% for the same number of finishing cycles. To study the surface characteristics of the finished spur gear tooth profile surface, scanning electron microscopy is used. The present developed theoretical model for surface roughness during the MRGPF process predicts the finishing performance with cycle time, improvement in the surface quality, and functional application of the gears.

Investigation of Noise Features of Planetary Gear Trains Based on Human Aural Characteristic

2017 ◽  
Author(s):  
Masao Nakagawa ◽  
Dai Nishida ◽  
Deepak Sah ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama
Keyword(s):  
Gear Tooth ◽  
Structural Complexity ◽  
Planetary Gear ◽  
Transmission Error ◽  
Sound Level ◽  
Tooth Surface ◽  
Surface Error ◽  
Planetary Gear Trains ◽  
Tooth Stiffness ◽  
Gear Trains

Planetary gear trains (PGTs) are widely used in various machines owing to their many advantages. However, they suffer from problems of noise and vibration due to the structural complexity and giving rise to substantial noise, vibration, and harshness with respect to both structures and human users. In this report, the sound level from PGTs is measured in an anechoic chamber based on human aural characteristic, and basic features of sound are investigated. Gear noise is generated by the vibration force due to varying gear tooth stiffness and the vibration force due to tooth surface error, or transmission error (TE). Dynamic TE is considered to be increased because of internal and external meshing. The vibration force due to tooth surface error can be ignored owing to almost perfect tooth surface. A vibration force due to varying tooth stiffness could be a major factor.

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