PRIN. OF INTERNAL COMBUSTION ENGINES - OD1619 LESSON 2/TASK 2
openings in the outer lobes.
This action is much like that in the gear-type pump.
c. Gear-Type Oil Pump (figure 52 on the following page). Gear-type oil pumps have
a primary gear that is driven by an external member, and which drives a companion
gear. Oil is forced into the pump cavity, around each gear, and out the other side
into the oil passages. The pressure is derived from the action of the meshed gear
teeth, which prevents oil from passing between the gears, forcing it around the
outside of each gear instead. The oil pump incorporates a pressure relief valve, a
spring-loaded ball that rises when the desired pressure is reached, allowing the
excess oil to be delivered to the inlet side of the pump.