Gerotor Pump: Applications & Efficiency Advantages

The gerotor pump is everywhere and almost invisible. Open the oil pan of most modern car engines and you will find one driving the lubrication circuit. Crack open a hydraulic power unit for a closed-loop drive system and you will probably find one serving as the charge pump. The design is simple enough to manufacture precisely at very low cost, smooth enough to run quietly, and compact enough to fit where other pump types will not.

What Makes the Gerotor Work

An inner rotor with one fewer tooth than an outer ring gear turns eccentrically inside the ring. The tooth count difference creates a series of expanding and contracting crescent-shaped spaces between the two rotors as they turn together. Fluid is drawn in through the expanding spaces on the inlet side and expelled through the contracting spaces on the outlet side. There are no reciprocating parts, no valve plates, no check valves in the basic design. The mechanism is as simple as positive displacement gets.

That simplicity translates directly into noise behavior. The internal mesh geometry eliminates the gear impact that makes external gear pumps audible across a machine room. Low noise is intrinsic to the gerotor design, not an engineered-in feature that adds cost.

Where Gerotors Fit in Hydraulic Systems

Low-pressure gerotor pumps are the standard solution for charge circuits in closed-loop axial piston pump installations. The charge pump maintains a minimum inlet pressure at the main pump suction, preventing cavitation at high operating speeds and low ambient temperatures. Without a functioning charge pump, main pump service life is dramatically shortened.

Cooling circuits pumps in thermal management systems also commonly use gerotor designs where the circuit fluid is oil or a viscous coolant blend — conditions where centrifugal pumps lose efficiency rapidly.

Maintenance Reality

Gerotor pumps run a long time without attention, which means shaft seal degradation is often ignored until external leakage becomes impossible to overlook. A slow shaft seal leak in a lubrication circuit can contaminate adjacent systems with hydraulic oil or allow lubricant to escape until bearing starvation occurs. HOVOO / HOUFU stocks seal kits for major gerotor platforms. HOUFU seals keep quiet pumps running quietly — hovooseal.com.

Source: www.hovooseal.com