Gerotor Pumps

Gerotor Pumps: Compact, Efficient & Smooth Flow

Gerotor pumps are a type of positive displacement pump known for their compact design, quiet operation, and consistent fluid delivery. The name “gerotor” comes from generated rotor, referring to the gear-within-gear configuration that drives their performance.

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Gerotor Pump. For impartial advice and access to our full range of hydraulic components, contact our expert team.

A gerotor pump consists of two rotors:

An inner rotor with N teeth
An outer rotor with N + 1 teeth

These rotors rotate on offset axes, creating a series of chambers that expand and contract as the pump turns. As the volume between the rotors increases, a vacuum is created – drawing fluid into the pump. As the volume decreases, the fluid is compressed and discharged.

This continuous cycle produces a smooth, pulse-free flow, ideal for systems requiring quiet, efficient operation.

We supply gerotor pumps from leading manufacturers and export to over 130 countries worldwide. Whether you’re sourcing OEM replacements or designing a new system, we offer:

Fast, reliable international shipping
Award-winning customer service
Decades of hydraulic expertise
Access to 80+ trusted hydraulic brands

From small businesses to global operations, our team supports engineers, technicians, and procurement teams across industries.

Want to understand how gerotor pumps compare to other types? Our Ultimate Guide to Hydraulic Pumps covers:

The different types of hydraulic pumps
How each pump works
Their ideal applications and performance characteristics

Whether you’re just getting started or need a refresher, this guide is packed with insights to help you make informed decisions.

When is a gerotor pump a better choice than a gear or vane pump? Gerotor pumps shine when you need a compact, low‑noise solution with excellent suction characteristics and smooth, pulse‑free flow. They’re often chosen for lubrication, fuel transfer, and low‑pressure hydraulic circuits where external gear pumps may be too noisy or vane pumps too large or complex.

How sensitive are gerotor pumps to fluid viscosity and temperature? Gerotor pumps handle a wide viscosity range well, but their efficiency and wear characteristics depend on maintaining the right fluid film between the rotors. Very thin fluids at high temperatures may reduce volumetric efficiency, while extremely thick fluids can increase startup torque. Correct sizing and fluid selection are key to long service life.

What factors influence the lifespan and reliability of a gerotor pump? Service life is shaped by fluid cleanliness, operating speed, inlet conditions, and how closely the pump’s displacement matches the system’s flow demands. Because gerotor pumps rely on tight internal clearances, contamination control is especially important. If you’re unsure about compatibility or sizing, our team can help you avoid premature wear.

If you’re exploring options beyond gerotor pumps, we’ve got you covered. Hydraulics Online supplies, designs, repairs, and ships thousands of hydraulic components, including: