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.

Performance Characteristics of Lubricating Oil Film Between Rotating Disks

1960 ◽  
Vol 82 (1) ◽  
pp. 19-28 ◽  
Author(s):  
S. I. El-Sisi ◽  
G. S. A. Shawki
Keyword(s):  
Testing Machine ◽  
Lubricating Oil ◽  
Test Results ◽  
Rotating Disks ◽  
Rolling Velocity ◽  
Oil Film ◽  
Gear Teeth ◽  
Pure Rolling ◽  
Theoretical Investigations ◽  
The Subject

A testing machine has been designed to investigate the performance of the lubricating oil film between two independently driven circular disks in line contact under conditions of combined rolling and sliding, in an endeavor to study the behavior of meshing gear teeth with adequate supply of lubricant. Test results show that the ratio of sliding to rolling velocity is a prime factor in the behavior of rotating disks. Values of this ratio equal to zero and unity (conditions of pure rolling and pure sliding, respectively) give rise to critical changes in the performance of the disks, being most favorable, from a lubrication viewpoint, at pure rolling (i.e., at the gear pitch line) and least favorable at pure sliding where scuffing of surfaces may well be expected Recent theoretical investigations do not seem to be able yet to account for salient results obtained in the present study. Further work on the subject is proceeding.

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.

scholarly journals Ligament and Droplet Generation by Oil Film on a Rotating Disk

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Hengchao Sun ◽  
Guoding Chen ◽  
Li’na Wang ◽  
Fei Wang
Keyword(s):  
Film Thickness ◽  
Flow Rate ◽  
Rotational Speed ◽  
Two Phase Flow ◽  
Rotating Disk ◽  
Droplet Generation ◽  
Phase Flow ◽  
Two Phase ◽  
Disk Radius ◽  
Oil Film

The lubrication and heat transfer designs of bearing chamber depend on an understanding of oil/air two-phase flow. As initial and boundary conditions, the characteristics of ligament and droplet generation by oil film on rotating parts have significant influence on the feasibility of oil/air two-phase flow analysis. An integrated model to predict the oil film flow, ligament number, and droplet Sauter mean diameter (SMD) of a rotating disk, which is an abstraction of the droplet generation sources in a bearing chamber, is developed based on the oil film force balance analysis and wave theory. The oil film thickness and velocity, ligaments number, and droplet SMD are calculated as functions of the rotating disk radius, rotational speed and oil volume flow rate and oil properties. The theoretical results show that the oil film thickness and SMD are decreased with an increasing rotational speed, while the radial, transverse velocities, and ligament number are increased. The oil film thickness, radial velocity, and SMD are increased with an increasing oil flow rate, but the transverse velocity and ligament number are decreased. A test facility is built for the investigation into the ligament number of a rotating disk, and the measurement of ligament number is carried out by means of a high speed photography.

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.

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