Crescent gear pump or motor having bearing means for supporting the ring

Abstract

A gear pump or motor comprising a body having a cavity with high pressure and low pressure ports. A pinion, an internally toothed ring gear meshing together, a filling member interposed between pinion and ring gear and an arcuate bearing member are housed within the cavity. The pinion has a shaft which is journalled in the body. The arcuate bearing member is interposed between the periphery of the ring gear and the body wall near the low pressure port and yieldingly supports the ring gear such that the latter can shift in a direction of a plane of eccentricity containing the axis of rotation of the pinion and the ring gear. The arcuate bearing member defines, at its outer face, an area of low pressure, which is smaller than a further area of low pressure at its inner face which areas of low pressure are connected to one another. The filling member has a sickle-shaped cross section with a tapering end and a rounded end and which is mounted for pivotal movement and axial shifting movement transversely to the pivot axis and to the longitudinal extension of the filling member.