Plunger oil pump with combined rotary and axial motion where plunger is made from two materials with different wear properties

摘要

The oil pump has a plunger (50) which consists of a pump head (52) formed of the same material as the body (10) and a drive section (54) made of a high wear resistant material. The end of the pump has a recess into which fits a projection from the drive section. At the rear of the drive section is a cam element for reciprocating motion. The drive section (54) contains gearing (60) on its periphery, which engages with a worm drive to give rotary motion. The drive contains bearing surfaces (62,64) on either side of the gearing.