Gear pump or motor with bearing passage for shaft lubrication

摘要

Gear pump and motor apparatus adapted to operate both as a pump and as a motor include two meshing gears whose shafts are supported in a housing chamber by respective bearing sleeves whose end faces sealingly engage the end faces of the respective gears. An oil supply passage is formed in each of the bearing sleeves in a region diametrically opposed to flat surface portions formed on the outer peripheral surface of the bearing sleeves and near a central plane which passes through the axes of cylindrical chamber portions in which the gears are situated. Oil leaking from the pump/motor chamber is directed into spaces defined between the peripheral surfaces of the bearing sleeves and the respective chamber portions through the oil supply passages into the bearing sleeve openings to lubricate the gear shafts which are received therein. The ratio of the length to the diameter of each of the oil supply passages is less than or equal to about 10.