Application of EHD Oil Film Theory to Industrial Gear Drives

1976 ◽  
Vol 98 (2) ◽  
pp. 626-631 ◽  
Author(s):  
E. J. Wellauer ◽  
G. A. Holloway
Keyword(s):  
Film Thickness ◽  
Surface Texture ◽  
Rapid Determination ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Composite Surface ◽  
Oil Film ◽  
Wide Range ◽  
Surface Distress ◽  
Gear Drives

The method and assumptions used for the application of EHD theory to the calculation of gear tooth oil film thicknesses for the design and analysis of industrial gear drives is presented. A nomograph, utilizing readily available gear geometry, operational, and lubricant parameters, is illustrated which allows rapid determination of calculated gear tooth oil film thicknesses for a wide range of gear drive conditions. Gear tooth surface distress is related to the specific film thickness, λ, the ratio of calculated oil film thickness to the magnitude of the composite surface texture. The term “surface texture” is introduced for gear contacts to indicate that surface attributes coarser than roughness importantly relate to tooth surface distress, but a sophisticated method for its quantitative assessment has not been developed. Data from several hundred petroleum lubricated laboratory tests and closely followed field applications which include through hardened gears of 1 in. to 15 ft in diameter are used to correlate specific film thickness and gear tooth surface distress. Curves are given to predict the probability of occurrence of such distress over the range of pitch line velocities of 4–35,000 ft/min.

Optimal Design of Modified Cylindrical Gear Based on Minimum Flash Temperature of Tooth Surfaces

2013 ◽  
Vol 655-657 ◽  
pp. 573-577
Author(s):  
Jin Ke Jiang ◽  
Zong De Fang ◽  
Xian Long Peng
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Contact Line ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Uniform Grid ◽  
Normal Vector ◽  
Flash Temperature ◽  
Oil Film ◽  
Tooth Surfaces

Considering the gap of the contact line of modified involute cylindrical gears influencing on loads, oil film thickness, the friction coefficient was determined on the basis theory of TCA、 LTCA and EHL. so oil film thickness and friction coefficient corresponded with loads on contact line were dispersed, which was used to computed discrete temperature according to the Blok flash temperature formula. and an approach of modified tooth surface optimum design based on the minimum flash temperature was proposed: the modified tooth surfaces was defined as a sum of theoretical tooth and cubic B-spline fit surface based on the uniform grid points created by double parabolas and a straight line and whose normal vector was deduced, besides, used genetic algorithm to optimize the parameter of curve, and get the best modified gear tooth surfaces. the results shows that oil film is thicker in engaging-out, coefficient of friction is contrary, which is responsible for lower flash temperature in engaging-in, besides the flash temperature has little changes in the single tooth meshing zone, and helical gear has a lower flash temperature than spur gear due to higher overlap ratio.

Estimation of Gear Friction Coefficient using Directional Parameter of Tooth Surface

2021 ◽  
pp. 1-27
Author(s):  
Junichi Hongu ◽  
Ryohei Horita ◽  
Takao Koide
Keyword(s):  
Friction Coefficient ◽  
Contact Surface ◽  
Gear Tooth ◽  
Correction Term ◽  
Tooth Surface ◽  
Oil Film ◽  
Tooth Surfaces ◽  
Frictional Coefficients ◽  
Finishing Processes ◽  
The Relationship

Abstract This study proposes a modification of the Matsumoto equation using a directional parameter of tooth surfaces to adapt various gear finishing processes. The directional parameters of a contact surface, which affect oil film formations, have been discussed in the field of tribology; but this effect has been undetermined on the meshing gear tooth surfaces having directional machining marks. Thus, this paper investigates the relationship between the gear frictional coefficients and the directional parameters (based on ISO25178) of their tooth surfaces with the various finishing processes; and modifies the Matsumoto equation by introducing a new directional parameter to augment the various gear finishing processes. Our findings indicate that through optimizing the coefficient of the correction term the include the new directional parameter, the calculated friction values using the modified Matsumoto equation correlate more highly to the experimental friction values than that using the unmodified Matsumoto equation.

Experimental study on line-contact elastohydrodynamic grease lubrication properties of surface-textured rollers

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fuqin Yang ◽  
Dexing Hu ◽  
Qianhao Xiao ◽  
Shun Zhao
Keyword(s):  
Film Thickness ◽  
Surface Texture ◽  
Inhibitory Effect ◽  
Lubricating Oil ◽  
Line Contact ◽  
Grease Lubrication ◽  
Content Type ◽  
Oil Film ◽  
Crown Width ◽  
Lubrication Properties

Purpose This paper aims to study line-contact elastohydrodynamic grease lubrication properties of surface-textured rollers as well as the effect of different crown widths (dw) on oil film thickness under textured conditions. Design/methodology/approach The laser processing method was used to make the micro-texture on the surface of GCr15 steel rollers; lithium grease was used as the lubricant, and line-contact elastohydrodynamic grease lubrication experiments under pure sliding conditions were performed on light interference elastohydrodynamic-lubricated experimental table. Findings The results show that the line-contact elastohydrodynamic grease lubrication is closely related to the textured crown width of steel rollers. At low speeds and light loads, texturing has an inevitable inhibitory effect on the formation of the lubricating oil film, and the smaller the width of the crown area, the more obvious the inhibitory effect, which is not conducive to the improvement of the lubrication condition. At high speeds and high loads, the textured roller with dw = 1 mm has the largest oil film thickness and shows better lubrication performance. Originality/value At present, there is little research on the surface texture of line-contact friction pairs. This work explores the effect of different textured crown width on the lubricating properties of line-contact elastohydrodynamic grease lubrication by experiment. It provides a new theoretical basis for the subsequent practical application of surface texture technology.

The Influence of Gear Parameters on Oil Film Thickness of Tooth Surface

2011 ◽  
Vol 79 ◽  
pp. 293-297
Author(s):  
Li Hong Liu ◽  
Zhan Ni Li ◽  
Han Bing Cao
Keyword(s):  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Gear Ratio ◽  
Tooth Surface ◽  
Speed Ratio ◽  
Oil Film ◽  
Single Tooth ◽  
Hydrodynamic Lubrication Theory ◽  
Tooth Flank ◽  
Center Distance

Applying elastic-hydrodynamic lubrication theory, oil film thickness of tooth surface was studies in accordance with the quasi-steady state. This paper focused on the influence of gear parameters such as gear ratio, module and center distance on the thickness of oil film of tooth flank. The results show, as speed ratio increases, oil film thickness increases significantly. When the number of teeth is fixed, oil film thickness increases significantly with the increase of module. When center distance is fixed, oil film thickness declines greatly with the increase of module in both into meshing and out of meshing points. Therefore when center distance is fixed, less module and more teeth are selected，on the condition that gear intensity is met. By results analyzing, the minimal oil film thickness may occur in the single tooth meshing area and into meshing or out of meshing points.

Simplified modellization of gear micropitting

2002 ◽  
Vol 216 (6) ◽  
pp. 291-302 ◽  
Author(s):  
F Antoine ◽  
J-M Besson
Keyword(s):  
Film Thickness ◽  
Thermochemical Treatment ◽  
Gear Train ◽  
Surface Finishing ◽  
Case Hardening ◽  
Reference Case ◽  
Oil Film ◽  
Epicyclic Gear ◽  
Wide Range ◽  
Physical Phenomena

This document gives a simplified method of calculating gear micropitting. The method has been developed by EUROCOPTER. The objective was to provide a model that took into consideration the maximum number of parameters in order to model the different physical phenomena, particularly: an oil-film thickness calculation taking the influence of pressure into consideration a simplified modellization of roughness an estimation of the plastification effect on the roughness overpressure at the contact surface taking into account the combined effects of roughness and oil-film thickness. The elaborated model is presented in an Excel file form. The application program is called APICS (approche du pitting par calculs simplifiés). In order to validate this model, this program has been applied to: An epicyclic gear train of a helicopter. Tests on discs as part of the ASETT European program. Discs are in hardened M50NiL Duplex (surface treatment: carburized and nitrided). Different kinds of surface finishing were proposed. The reference case of discs in 16NCD13 without thermochemical treatment has been also treated. FZG gear benchtests, also as part of the ASETT program. Gears have been manufactured in hardened M50NiL Duplex, with different kinds of surface finishing proposed. The results of the calculations express quite exactly the experimental facts observed on discs and gears for a wide range of studied cases, covering different materials, different kinds of case hardening and different kinds of surface finishing.

Research on Gear Cutter Tooth Profile for Semi-Topping: A Case of a Helical Gear

1992 ◽  
Author(s):  
Y. Ariga ◽  
Shiyeyoshi Nagata
Keyword(s):  
Design Method ◽  
Gear Tooth ◽  
Helical Gear ◽  
Tooth Profile ◽  
Tooth Surface ◽  
Gear Cutting ◽  
Gear Cutter ◽  
Conventional Design ◽  
Wide Range ◽  
Tooth Number

Abstract Gear tooth tips are frequently chamfered to prevent nicks or scuffing on the tooth surface. Some of the hob cutters and pinion cutters can be chamfered but many types of cutters should be used for a particular range of tooth numbers since the amount chamfering largely varies depending on the tooth number. However, intensive efforts in the design have made it possible to produce cutters with little variation of chamfering amount for a wide range of tooth numbers. The error in the amount of chamfering by a single cutter designed by the above method can be maintained within ±10 % for gears with tooth numbers ranging from 16 to 94. It was found that three cutters of the conventional design are required for keeping the error within the same range for cutting gears within a given range of tooth numbers. The paper describes the tooth design method of the hob cutter with little variation of chamfering amount along changes in number of teeth to be machined and demonstrates that chamfering errors are maintained within practically allowable ranges for profile shift cutting or helical gear cutting with the use of this cutter.

T1101-2-5 Effect of surface texture on oil film thickness of slideway

2009 ◽  
Vol 2009.8 (0) ◽  
pp. 197-198
Author(s):  
Hayato Ogawa ◽  
Shinya Sasaki ◽  
Atsushi Korenaga ◽  
Koji Miyake ◽  
Miki Nakano ◽  
...  
Keyword(s):  
Film Thickness ◽  
Surface Texture ◽  
Oil Film ◽  
Effect Of Surface

Measurement of Oil Film Thickness Between W-N Helical Gear Tooth Profiles Using Laser Transmission Method

1990 ◽  
Vol 112 (4) ◽  
pp. 708-711 ◽  
Author(s):  
Yang Ji-Bin ◽  
Qi Yu-Lin ◽  
Chen Chen-Wen
Keyword(s):  
Film Thickness ◽  
Gear Tooth ◽  
Helical Gear ◽  
Spur Gears ◽  
Measuring Apparatus ◽  
Transmission Method ◽  
Helical Gears ◽  
Oil Film ◽  
Measurement Results ◽  
First Time

In this experiment, it was the first time that the center oil film thickness between W-N helical gear tooth profiles has been measured indirectly through measuring the change of gaps of a pair of unloaded involute spur gears mounted on the extended shafts of W-N gear box by means of laser transmission method. During the measurement of every time, it was calibrated separately, so that all errors could be eliminated completely except ones of measuring apparatus. The accuracy of this method has reached 0.1 μm (dynamic) and 0.01 μm (static), respectively. Measurement results were identical with theoretical ones. This method is also suitable for the measurement of center oil film thickness between tooth profiles and deformation of any cylindrical spur and helical gears.

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