Investigation of the influence of oil film thickness on helical gear defect detection using Acoustic Emission

2014 ◽  
Vol 79 ◽  
pp. 42-46 ◽  
Author(s):  
Mhmod Hamel ◽  
Abdulmajid Addali ◽  
David Mba
Keyword(s):  
Acoustic Emission ◽  
Film Thickness ◽  
Defect Detection ◽  
Helical Gear ◽  
Oil Film

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.

Acoustic Emission and Elastohydrodynamic Film Thickness for Meshing of Spur and Helical Gear

2007 ◽  
Author(s):  
R. I. Raja Hamzah ◽  
D. Mba
Keyword(s):  
Acoustic Emission ◽  
Film Thickness ◽  
Experimental Evidence ◽  
Liquid Nitrogen ◽  
Gear Wheel ◽  
Helical Gear ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Helical Gears ◽  
Test Conditions

This paper presents experimental evidence of the correlation between Acoustic Emission (AE) activity and the specific film thickness (λ) for operational spur and helical gears. Whilst recording AE activity for a range of test conditions the specific film thickness was varied during operation by spraying liquid nitrogen onto the rotating gear wheel. It was noted that the AE activity reduced significantly as the theoretically estimated specific film thickness increased. It is concluded that the measurements of AE activity may offer an opportunity to quantify the level of asperity contact for meshing gears under a range of operating conditions.

The Surface-Roughness of Bearing-Surfaces and its Relation to Oil Film Thickness at Breakdown

1949 ◽  
Vol 161 (1) ◽  
pp. 73-79 ◽  
Author(s):  
A. Cameron
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Hydrodynamic Theory ◽  
Quantitative Relation ◽  
Metal Contact ◽  
Initial Contact ◽  
Frictional Drag ◽  
Average Roughness ◽  
Finished Steel ◽  
Oil Film

In this paper the relation of surface roughness of bearing surfaces to allowable film thickness is studied quantitatively with a simple Michell pad apparatus. The pads used were faced with white metal and ran against mild steel collars. The lubricants studied were water, soap solution, paraffin, and light oil. There was little difference in the frictional behaviour of any of the lubricants, except that the aqueous lubricants would not run with very finely finished steel surfaces. The onset of metal to metal contact was detected by an increase in the frictional drag, and also by the change in electrical conductivity between the pad and collar—an extremely sensitive method. The paper shows that there is, at any rate for this system, a quantitative relation between the total surface roughness of the rubbing surfaces and the calculated oil film thickness both at the initial metal to metal contact and seizure. Initial contact occurs when the outlet film thickness, calculated from normal hydrodynamic theory, falls to three times the maximum surface roughness and seizure occurs when it is double the average roughness.

Influence of Surface Waviness on the Thermal Elastohydrodynamic Lubrication of an Eccentric-Tappet Pair

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
J. Wang ◽  
C. H. Venner ◽  
A. A. Lubrecht
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Surface Waviness ◽  
Film Pressure ◽  
Oil Film ◽  
Working Cycle ◽  
Temperature Oscillations ◽  
Minimum Film Thickness ◽  
Traction Coefficient ◽  
Oil Film Pressure

The effect of single-sided and double-sided harmonic surface waviness on the film thickness, pressure, and temperature oscillations in an elastohydrodynamically lubricated eccentric-tappet pair has been investigated in relation to the eccentricity and the waviness wavelength. The results show that, during one working cycle, the waviness causes significant fluctuations of the oil film, pressure, and temperature, as well as a reduction in minimum film thickness. Smaller wavelength causes more dramatic variations in oil film. The fluctuations of the pressure, film thickness, temperature, and traction coefficient caused by double-sided waviness are nearly the same compared with the single-sided waviness, but the variations are less intense.

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