The correlation between gear contact friction and ball on disc friction measurements

Abstract

Running experiments with full-size gearboxes from the actual application has the advantage of giving realistic results in terms of power losses. The drawback is extensive costs, lengthy testing, and the difficulty in differentiating between load dependent and load independent losses, and which losses are coming from the gears, seals, bearings or synchronizers. In this work, the correlation between friction measurements conducted in a ball-on-disc machine and friction measurements conducted in a back-to-back gear rig is investigated. The correlation between the gear tests and the ball-on-disc tests were reasonably good in terms of absolute values, and the shape of the friction curves were similar, indicating that the ball-on-disc measurements to a large extent are capturing the behavior of the gear contact.

Friction Mapping as a Tool for Measuring the Elastohydrodynamic Contact Running-in Process

“…Mapping out the friction coefficient over a large range of entrainment velocity and slip provides an excellent measure of general lubricant and surface properties, and the information gained can be correlated to gear tooth mesh behavior. 22 However, to accurately simulate the running-in for a gear tooth, a somewhat different procedure must be used. Any point along the gear tooth face in a spur gear contact will experience a single value of slip with the entrainment velocity changing as the gear is started, operated at various speeds, then stopped.…”

“…Björling et al have used friction mapping with entrainment velocity and slip to study friction coefficient, surface roughness, lubricant viscosity and type, surface material, and lubrication regime. [19][20][21][22] By mapping over these variables during the running-in process, we can also study the contact history that cause running-in and the friction coefficient that one can expect during and after the running-in process.…”

A Review on Tribological Wear Test Rigs for Various Applications

“…The disc's diameter was in 10.16 cm, and the balls were in diameter of 2.063 cm under different types of lubricant. The test was performed under 76 N load, speeds of 1 m/s to 4 m/s, with temperatures of 40 o and 70 o , pressure of 1.24 GPa, and 0.0002 -1.2 Slide to Roll Ration (SRR)[42]. EHL tribological systems is presented by Björling et al with different parameters and conditions.…”

Contribution to the Assessment of the Potential of Low Viscosity Engine Oils to Reduce ICE Fuel Consumption and CO2 Emissions

“…5 different engine oil formulations were used, however, it should be mentioned that the viscosity effect was only studied indirectly varying the temperature from 30°C to 140°C, the different formulations corresponded to different degrees of fricton modifier additives. The study found a significant engine friction reduction as temperature risen, the authors claimed correlations of those friction tests with previous fuel economy tests, concluding that a 11% friction reduction led to 1% fuel economy differences [60].…”

“…In order to complete the engine and fleet tests, two tribometers were used to mimic certain ICE tribocontacts; the Cameron Plint Machine TE77 reciprocating rig, widely used to reproduce the piston ring/cylinder liner contact [47][48][49][50][51][52][53][54][55] and the WAM Ball-onDisc machine, which is normally used to reproduce valvetrain and transmission gears tribocontacts [56][57][58][59][60] were used alongside some of the engine oils used in the fleet test.…”