Hydraulic gear pump with recesses in non-working gear flanks

摘要

A gear pump has a pair of externally meshed gears, and an inlet port and an outlet port on respective sides of the zone of mesh of the gears. The teeth of the gears have their non-working flanks relieved so as to increase an inter-tooth volume lying between two adjacent contact areas of the gears, this inter-tooth volume first decreasing and then increasing as the gears rotate. The relief of the non-working flanks is such that each successive inter-tooth volume communicates with the inlet port before that volume increases from its minimum value.