Measurement Of Friction In Conformal Contacts

This project is mainly focused on the measurement of the friction in a lubricatedconformal contact formed by a fixed-incline slider bearing/a step bearing.For measurement of friction in a conformal contact, friction measurement systemhas been set up based on the existing slider-on-disc oil film thickness tester. Using thetest apparatus, accurate measurement of friction in a conformal contact can be achievedunder prescribed inclinations, velocities, loads and oils.The friction torque of the thrust ball bearing, which is a support of the load lever,was studied by a mutual pull of two force sensors. Different torques were obtainedwhen the sensors were located at different positions, and an optimum position for forcesensors was determined. Correction formula for friction measurements were derivedaccording to the measurements.Using the built system experimental studies were carried out to obtain the filmthickness and the friction for a fixed-incline slider. By parameter conversionrelationship of dimensionless friction coefficient (μB/h0) and convergence ratio K couldbe obtained, and its dependences on the load and the inclination were obtained. Theresults showed that the measured friction and the theoretical prediction agreequalitatively; Experiments were carried out to study the film thickness and the frictionbetween two parallel surfaces in a step bearing. The film thickness vs. speed and thefriction vs. speed have been gotten under different loads. By parameter conversionrelationship of dimensionless friction coefficient (μl/sh) and dimensionless filmthickness H0could be obtained. It was shown that when the lubrication was decided bythe hydrodynamic effect of geometry of the step bearing, the measured dimensionlessfriction coefficient showed the same tendency, when the lubrication was generatedmainly by local hydrodynamic effect caused by surface roughness, the measureddimensionless friction coefficient is different with the theoretical curve.