What Types of Hydraulic Gear Pumps Are Available?

Hydraulic gear pumps suppliers are fundamental components in a vast array of machinery, from agricultural equipment and construction vehicles to industrial manufacturing systems. Their primary role is to convert mechanical energy into hydraulic energy by moving fluid, creating the flow and pressure necessary to power hydraulic circuits. Their popularity stems from a straightforward design, cost-effectiveness, and general robustness. When embarking on a project that requires such a pump, understanding the available types is a crucial step. This knowledge not only informs the design and specification process but also guides you in your conversations with potential Hydraulic Gear Pump Suppliers. The main categories of hydraulic gear pumps are defined by their gear geometry and how they manage the fluid within the pumping chambers.

External Gear Pumps

External gear pumps are the common and widely recognized type. Their design is characterized by two identical, interlocking gears—a driven gear and an idler gear—that rotate within a closely fitted housing. As the gears unmesh on the inlet side, they create a void, allowing fluid to be drawn into the pump. This fluid is then carried in the spaces between the gear teeth and the housing wall to the outlet side. As the teeth mesh again on the discharge side, the fluid is forced out, creating flow.

Simple and Durable Construction: With only two moving parts, their design is uncomplicated, high reliability and ease of manufacture.

Cost-Effective: They are generally the economical option, offering good performance for a wide range of medium-pressure applications.

Fixed Displacement: Many standard models are fixed displacement, meaning they move a specific volume of fluid per revolution.

Common Applications: These pumps are frequently used in machine tools, power steering systems, and lubrication systems, as well as in various mobile and industrial hydraulics.

When consulting with Hydraulic Gear Pump Suppliers, you will find that external gear pumps are often the default recommendation for standard-duty tasks. They handle a variety of hydraulic fluids with reasonable efficiency and are available in a multitude of sizes and pressure ratings. Their main limitations include a fixed, non-adjustable flow rate and a tendency to generate more audible noise at higher pressures and speeds compared to some other pump types.

Internal Gear Pumps

Internal gear pumps operate on a similar principle but with a different mechanical arrangement. This design features a smaller external gear (the rotor) that meshes inside a larger, ring-shaped internal gear (the idler). A crescent-shaped partition is fixed between the two gears, which acts as a seal between the inlet and outlet ports. As the gears rotate, fluid is trapped in the spaces created between the crescent and the gear teeth, moving from the inlet to the outlet.

Compact and Smoother Operation: The internal meshing of the gears often results in quieter and smoother flow compared to external gear designs.

Good Suction Characteristics: They are particularly adept at handling fluids with higher viscosities and can prime themselves well, making them suitable for a range of fluids beyond standard hydraulic oil.

Single Direction of Flow: The design is inherently unidirectional.

Common Applications: Their gentle pumping action makes them ideal for lubricating oils, fuel transfer, polymers, and other sensitive fluids.

This type of pump offers a valuable balance of performance and compactness. Reputable Hydraulic Gear Pump Suppliers will often suggest internal gear pumps for applications where space is a constraint and a quieter, more consistent flow is desired, especially with more viscous fluids. While they can be slightly more complex to manufacture than external gear pumps, their performance benefits in specific scenarios make them a compelling choice.

Gerotor Pumps

Gerotor pumps are a specialized subset of internal gear pumps. They also consist of an inner and outer rotor, but the design differs. The inner rotor, which has one less lobe than the outer rotor, is driven and causes the outer rotor to rotate. As they turn, the spaces between the lobes change volume, drawing in fluid at the inlet and expelling it at the outlet. There is no fixed crescent seal; the sealing is achieved through the precise meshing of the rotor lobes.

High Volumetric Efficiency: The tight tolerances and continuous sealing line can very good efficiency for their size.

Compact and Balanced Design: They offer a high power density, delivering significant flow from a small package, and their rotating assembly is typically well-balanced.

Common Applications: Gerotor pumps are frequently employed in engine lubrication systems, transmission systems, and as charge pumps for larger, more complex hydraulic systems.

The high efficiency and compact nature of gerotor pumps make them a go-to solution for integrated systems within engines and transmissions. When discussing requirements with Hydraulic Gear Pump Suppliers, it is useful to inquire about gerotor options for applications where package size is a critical factor and high efficiency is required at moderate pressures.