Patent ID: 6592348
Filing Date: 2003-07-15
Classification: F04C,F05C,Y10T

Abstract:
A method of producing a lubrication pump for a vehicle transfer case, the method comprising:forming a pump body, the pump body having a generally hollow cylindrical shape and a central longitudinal axis, one end of the pump body having a radial wall with a centrally disposed aperture; molding a pump insert from a synthetic polymer, the pump insert having a generally cylindrical main body with a central aperture, an inlet channel formed in the main body and adapted for fluid communication with a source of lubricating fluid, and an outlet channel formed in the main body in fluid communication with the central aperture of the main body; molding an outer gear from a synthetic polymer, the outer gear being generally ring shaped with an inner surface forming an aperture, the inner surface having a generally sinusoidal shape which forms a plurality of peaks and valleys; molding an inner gear from a synthetic polymer, the inner gear being generally disc shaped with a central aperture formed by an inner surface, the inner surface having a shaft engaging portion to drivingly engage the inner gear with a shaft of a vehicle transfer case, an outer surface of the inner gear having a generally sinusoidal shape which forms a plurality of peaks and valleys, the number of peaks and valleys being at least one less than the number of peaks and valleys of the inner surface of the outer gear, the inner gear rotatingly received in the central aperture of the outer gear; forming a pump cover, the pump cover being generally disc shaped and having a central aperture; inserting the pump insert into the pump body; mating the inner gear and the outer gear by aligning at least one of the valleys of the outer gear with at least one of the peaks of the inner gear and inserting the mated inner gear and outer gear into the pump body adjacent the pump insert; joining the pump cover and the pump body to form a substantially liquid tight seal between the pump body and the pump cover.