| Summary: | 博士 === 國立成功大學 === 機械工程學系 === 86 === A gear/cam adapter was employed to study various aspects of
line-contact lubrication, using oil with extreme-pressure at two
different concentrations. The effect of run-in on the
tribological performance of rollers with two different surface
roughnesses was investigated in terms of friction coefficient,
wear loss, oil temperature, specimen roughness and electrical
resistanc?蒞he relation between roller wear loss and the time
rate of electrical resistance change was established. The run-in
effect on roller wear loss in smooth rollers is opposed to that
in rough rollers. The asperity height of the smooth rollers was
increased by wear testing irrespective of run-in; however, run-
in enhanced the increase in surface roughness. The extreme-
pressure additive concentration instead of run-in was the
decisive factor in electrical resistance. Friction coefficient
during testing showed a strong positive relation with composite
surface roughness. The pitting behavior of rollers with two
different surface roghnesses was investigated in terms of crack
length, chemical reaction thin film, pitting area, pitting
depth, and specimen''s life. Rollers with a rough contact surface
induced a longer life by means of a shallower stress
distribution in the subsurface. The presence of extreme-pressure
additive in the base oil reduced Weibull slope and promoted the
L50 life. The results were confirmed due to the plastic flowing
of Beilby layer, which restrained the propagation of cracks.
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