What are the two common structural types of oil pumps?

[LeColton]

There are two common structural types of oil pumps. Below are the specific introductions to these common structural types of oil pumps: 1. Gear-type oil pump: The oil pump housing is machined with an inlet and an outlet. Inside the oil pump housing, there is a driving gear and a driven gear. There is a very small gap between the gears and the inner wall of the housing. The working principle is that when the gears rotate clockwise, the volume of the inlet chamber increases as the gear teeth move away from the meshing direction, creating a certain degree of vacuum. The lubricating oil is then drawn from the inlet and fills the inlet chamber. The rotating gears carry the lubricating oil between the teeth to the oil chamber. As the gear teeth enter the meshing state, the volume of the outlet chamber decreases, increasing the oil pressure. The lubricating oil is then delivered to the engine oil passage through the outlet. 2. Rotor-type oil pump: The oil pump housing contains an inner rotor and an outer rotor. The inner rotor is fixed to the driving shaft with a key, and the outer cylindrical surface of the outer rotor fits with the housing, with a certain eccentricity between them. The outer rotor is driven by the inner rotor to rotate. The housing is equipped with an inlet pipe and an outlet. The working principle of the rotor-type oil pump is that during the rotation of the inner and outer rotors, the tooth profile of each tooth of the rotors always forms point contact with each other, creating four enclosed working chambers between the inner and outer rotors. Since the outer rotor always rotates slower than the inner rotor, the volumes of these four working chambers continuously change.