How a Gear Pump Works

A hydraulic gear pump is a component on your vehicle that is used to pump hydraulic fluid to various points in your car. In most cases, they are used to provide hydraulic fluid to hydraulic motors and actuators and use two meshed gears inside a sealed case to accomplish this.

How They Work

A gear pump is able to pump hydraulic fluid to other components in your car that need the fluid through a series of gears and an inlet and outlet valve. A gear pump can be connected to either a diesel or a gasoline motor, which is used to supply the energy needed to power the pump. Once hydraulic fluid enters a gear pump enclosure, the gears in the system turn in opposite directions in order to push fluid from the inlet valve out through the outlet valve.

Fluid is drawn in to the inlet valve from the outer layer of the gear pump case, and the meshing of the gears prohibits the fluid from flowing backwards toward the inlet valve. Rather, because the gears mesh in the middle of the assembly, the fluid is continuously pushed toward the outlet valve.

Generally speaking, the gear pump is the center of your vehicle's hydraulic system. Once the fluid is drawn out of its reservoir tank, it is pumped into a pressurized tube. The gear pump is operated at a constant speed in order to provide consistent pressure throughout the system. Once the fluid is pushed through the inlet valve and meshed gears, a vacuum is created behind the gears that serves to draw in even more fluid. That hydraulic pressure is used to power several hydraulic devices in your vehicle.

Gear Pump Design Basics

In most cases, a gear pump is located inside an airtight, sealed case or enclosure. Also, there is usually an outer gear that is positioned outside of the case that is used to create an additional seal. A smaller inner gear is then used on one side of the case and is fitted so that it meshes tightly with the outer gear.

At the point where the gears mesh together, there are gaps between the gears. In relation to the case as a whole, the meshed gears are usually centered between the point where the fluid enters the case, or the inlet port (sometimes also referred to as a suction port), and the point where the fluid flows out of the case, the outlet port. A small motor is attached to the internal gear and is used to drive the entire pump mechanism.

Vehicle Systems that Use a Gear Pump

The most common component in many cars that utilize a gear pump is the vehicle's transmission. However, some vehicles use hydraulic pumps in other areas as well. In addition, many commercial vehicles use hydraulic pumps. For instance, cranes use hydraulic gear pumps to provide power to turn the arm, turn the tracks and even raise and lower the winch. Likewise, dump trucks use hydraulic gear pumps to raise and lower the dump bed.