Viscous fluid metering device

摘要

A metering device having two gears and a center plate defining a gear chamber having two major lobes to receive the gears, each of the major lobes defining a diameter and a circular segment having a perimeter extending greater than one hundred eighty degrees. The face surfaces of the first gear, the second gear and the center plate are each machined to be as precisely flat as practical and to be as precisely of equal thickness as practical. The first gear and the second gear are trued on an arbor to eliminate as much runout as practical while at the same time reducing a diameter of the first gear and the second gear to be the substantially the same or slightly larger than the diameter of the major lobes. The first gear and the second gear are press fit into the major lobes; and lapped in the major lobes.