Gearing with mating internal and spur gears

This invention relates to improvements in gearings in general, and more particularly to improvements in gearings of the type wherein an internal gear surrounds a second gear having an annulus of external gear teeth in mesh with the annulus of gear teeth forming part of the internal gear. Gearings of the type to which the present invention pertains are often utilized in pumps, e.g., in so-called internal gear pumps which serve to supply a lubricant (such as oil) to various constituents of the power train in a motor vehicle. A gearing, particularly for use in a gear pump which can be utilized in the power train of a motor vehicle, has a housing, a rotary internal gear in the housing, and a spur gear driven by a prime mover, mating with the internal gear and defining with the latter a crescent-shaped chamber for forcible conveying of a fluid, such as lubricant, from an inlet communicating with one end portion to an outlet communicating with the other end portion of the chamber. In order to avoid turbulent flow of fluid in the chamber, the latter is substantially filled by a composite insert. Such insert can comprise several crescent-shaped fillers with at least one seal between them, or two one-piece or composite fillers which are disposed end-to-end as seen in the circumferential direction of the internal gear and are separated from each other by an abutment which is secured to or of one piece with the housing.