The influence of permeability on the bearing performance of the oil impregnated tin bronze sintered bearing

Abstract

The oil impregnated tin bronze sintered bearing is one of the most popular industrial material in the sintered mechanical parts. A number of investigators have been studying about the conditions suitable for the bearing performance of this material. However, factors affecting the bearing performance are so many and complex that those systematic relations have not been clarified completely. Therefore, we picked up the oil supply efficiency of oil supply as one of the factors and discussed it's relation to the bearing performance, by using the two kinds of oil impregnated tin bronze sintered bearings; one is made from the pre-alloyed powders. In this case we assumed the efficiency of oil supply is closely related to the permeability.
Results. obtained were as follows:
1) Despite of coincidence of the composition and the intercommunicating porosity of the bearings, the per-meability of the bearing made from the pre-alloyed powders is higher than that made from the mixed powders, where all the powders used in this experiment were obtained as commercial ones and these particle sizes were all minus 100 mesh.
2) Under the condition of low speed operation, the bearing performance of the bearing made from the pre-alloyed powders was superior to that made from the mixed powders. On the other hand, under the condition of high speed operation those differences were not measured.
3) The hardness of matrix affects the bearing performance, e.g. the harder the matrix, the lower the frictional coefficient and the temperature increment of bearings in general where the hardness of matrix was varied by the tin content of the bearing.
5) Radial crushing strength of the bearings made from the prealloyed powder was about twice as high as those made from the mixed powders.