Abstract
It was known in the first fundamental study that in the light load and very high speed revolution region (2-6 kg/cm2, above 20, 000 rpm), sintered bearings could be driven under hydrodynamic lubrication after achieving sufficiently good conformity. In the actual applications, however, the state of the lubrication at the start-up becomes a severe boundary owing to insufficient conformity, consequently a large amount of wear occurs or the bearings may seize.
On the basis of the above-mentioned study, a new Cu-Sn-P-MoS2 type bearing has been developed, which showed excellent performance under both boundary and hydrodynamic conditions. The distinctive features of the bearing are as follows; the thin layer of the reaction product (phosphorus compound) formed around the MoS2 particles in the sintered structure acted as a kind of binder between the matrix and the MoS2 particles, thus preventing the solid lubricant (MoS2) from mixing into the lubricant oil, which causes the increase in the apparent viscosity of the oil and consequently the coefficient of friction and the bearing temperature under the hydrodynamic conditions.
