The Measurement of Oil-Film Thickness in Gear Teeth

1960 ◽  
Vol 82 (1) ◽  
pp. 29-34 ◽  
Author(s):  
I. O. MacConochie ◽  
A. Cameron
Keyword(s):  
Film Thickness ◽  
Voltage Drop ◽  
Theoretical Work ◽  
Discharge Voltage ◽  
Constant Current ◽  
Oil Film ◽  
Gear Teeth ◽  
Order Of Magnitude ◽  
The Difference ◽  
Experimental Values

The voltage drop across thin oil films when a constant current of 1 amp is passed, i.e., the discharge voltage, is used to measure the oil-film thickness between loaded gear teeth while running. It is found that the thickness at the pitch line is between 1 and 4 × 10−4 in., which varies slightly with the viscosity and rather more strongly with load. The thickness at the tips and roots is very dependent on the tip relief. The conditions here may explain the difference between disk and gear tests. These experimental values are compared with theoretical work and are shown to be of the same order of magnitude.

Experimental Investigation of the Minimum Oil-Film Thickness in Spur Gears

1963 ◽  
Vol 85 (3) ◽  
pp. 451-455 ◽  
Author(s):  
D. W. Dareing ◽  
E. I. Radzimovsky
Keyword(s):  
Film Thickness ◽  
Voltage Drop ◽  
Planetary Gear ◽  
Gear Train ◽  
Spur Gears ◽  
Minimum Thickness ◽  
Testing Technique ◽  
Oil Film ◽  
Gear Teeth ◽  
Gear Drive

As a pair of gears is loaded, the minimum oil-film thickness between the gear teeth decreases and can approach a magnitude equal to the magnitude of the surface roughness. Metal-to-metal contact then occurs between the microscopic peaks on both mating teeth surfaces. Therefore, the minimum thickness of the film separating the mating teeth surfaces may be considered as one of the criteria of capacity for a gear drive. A testing technique that was developed for measuring oil-film thickness between loaded gear teeth while running is presented in this paper. The voltage drop across a thin oil film that is required to cause an electrical discharge was used to determine the oil-film thickness. A specially designed machine containing a planetary gear train was used in these experiments. The relationships between the minimum oil-film thickness and the load transmitted by the gearing under certain conditions were determined using this method.

scholarly journals Anti-symmetric Compton scattering in LiNiPO4: Towards a direct probe of the magneto-electric multipole moment

2021 ◽  
Vol 1 ◽  
pp. 132
Author(s):  
Sayantika Bhowal ◽  
Daniel O'Neill ◽  
Michael Fechner ◽  
Nicola A. Spaldin ◽  
Urs Staub ◽  
...  
Keyword(s):  
Compton Scattering ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Theoretical Work ◽  
Multipole Moment ◽  
Compton Profile ◽  
Magnetoelectric Materials ◽  
Order Of Magnitude ◽  
The Difference ◽  
Electric Multipole Moment

Background: Magnetoelectric multipoles, which break both space-inversion and time-reversal symmetries, play an important role in the magnetoelectric response of a material. Motivated by uncovering the underlying fundamental physics of the magnetoelectric multipoles and the possible technological applications of magnetoelectric materials, understanding as well as detecting such magnetoelectric multipoles has become an active area of research in condensed matter physics. Here we employ the well-established Compton scattering effect as a possible probe for the magnetoelectric toroidal moments in LiNiPO4. Methods: We employ combined theoretical and experimental techniques to compute as well as detect the antisymmetric Compton profile in LiNiPO4. For the theoretical investigation we use density functional theory to compute the anti-symmetric part of the Compton profile for the magnetic and structural ground state of LiNiPO4. For the experimental verification, we measure the Compton signals for a single magnetoelectric domain sample of LiNiPO4, and then again for the same sample with its magnetoelectric domain reversed. We then take the difference between these two measured signals to extract the antisymmetric Compton profile in LiNiPO4. Results: Our theoretical calculations indicate an antisymmetric Compton profile in the direction of the ty toroidal moment in momentum space, with the computed antisymmetric profile around four orders of magnitude smaller than the total profile. The difference signal that we measure is consistent with the computed profile, but of the same order of magnitude as the statistical errors and systematic uncertainties of the experiment. Conclusions: While the weak difference signal in the measurements prevents an unambiguous determination of the antisymmetric Compton profile in LiNiPO4, our results motivate  further theoretical work to understand the factors that influence the size of the antisymmetric Compton profile, and to identify materials exhibiting larger effects.

Elastohydrodynamic Lubrication of Hypoid Gears

1981 ◽  
Vol 103 (1) ◽  
pp. 195-203 ◽  
Author(s):  
V. Simon
Keyword(s):  
Film Thickness ◽  
Numerical Solution ◽  
Elastohydrodynamic Lubrication ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Temperature Variations ◽  
Hypoid Gears ◽  
Oil Film ◽  
Gear Teeth ◽  
Energy Equations

The full thermal elastohydrodynamic analysis of the lubrication of hypoid gears is presented. A numerical solution of the coupled Reynolds, elasticity and energy equations for the pressure, temperature and film thickness is obtained. The temperature variations across the oil film and in the pinion and gear teeth are included. The real tooth geometry of the modified hypoid gears is treated. The effect of the operating conditions on the performance characteristics is discussed.

Measurement of Oil-Film Thickness Between Disks by Electrical Conductivity

1960 ◽  
Vol 82 (1) ◽  
pp. 12-16 ◽  
Author(s):  
S. I. El-Sisi ◽  
G. S. A. Shawki
Keyword(s):  
Electrical Conductivity ◽  
Film Thickness ◽  
Testing Machine ◽  
Rotating Disk ◽  
Substantial Improvement ◽  
Film Resistance ◽  
Test Results ◽  
Oil Film ◽  
Gear Teeth ◽  
Special Apparatus

A special apparatus is designed to measure the oil-film thickness between two stationary disks (simulating meshing gear teeth) by applying a-c or d-c potential across the film and measuring its resistance for given gap between the disks. Experiments show that the treatment of oil with additive (sodium-petroleum sulphonate in this case) may well lead to a considerable increase in its electrical conductivity, and to a substantial improvement in the independence of the oil-film resistance of the electrical history and temperature of the oil. A reliable relationship could eventually be obtained between the oil-film resistance and relevant thickness. Test results are employed in investigating the behavior of the oil film in a rotating-disk testing machine developed by the authors for studying the performance of meshing gear teeth with adequate supply of lubricant.

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