Hydraulic motors are able to produce much more power than electric motors of the same size and for this reason are used for larger loads.
Hydraulic gear motors are one design of hydraulic motors, which are often part of a hydraulic drive system or hydraulic transmission along with hydraulic pumps and cylinders. The main enclosure and interior components are made from metal such as steel or iron so they can withstand high pressures and fast operating speeds. Hydraulic gear motors are a very common design of hydraulic motors and are widely used in aircraft, heavy duty vehicles, industrial lifting and in machinery that requires strong pressurized actions.
Additionally, hydraulic motors are frequently used to power automated manufacturing systems. Hydraulic motors are also used in trenchers, automobiles, construction equipment, drives for marine winches, waste management and recycling processes, wheel motors for military vehicles, self-driven cranes, excavators, forestry, agriculture, conveyor and auger systems, dredging and industrial processing.
Hydraulic motors are fairly simple machines that are composed of a reservoir, a pump and rotating machinery. The pump is connected by a line to a motor that draws the fluid, which is usually oil or water, from a reservoir and into the motor. The fluid forces motion by the moveable parts of the motor as it rotates. The rotation of the motor turns a coupled shaft which provides mechanical motion; the motor serves as the actuator that converts the pressure of the fluid into torque and rotational energy.
The fluid is discharged, filtered and reused. Hydraulic gear motors have meshed gears inside the motor; oil is pumped into this gear box to exert force on the gears which causes them to rotate and generate energy. Hydraulic gear motors are the least expensive and have the ability to operate at high speeds. However, they are also the noisiest of the hydraulic motors and are relatively inefficient at low speeds. Besides gear motors, there are vane and piston type hydraulic motors.
Vane motors have small parts that slide in and out of slots in a rotating wheel. Piston type motors have a pair of pistons distanced apart by tubing filled with hydraulic fluid. When a piston moves, the next piston will also move as a result of the incompressible hydraulic fluid. The hydraulic fluid transfers the pressure from the first piston, plus the built up pressure in the fluid to the next piston.