Hydraulic motors have a wide wide range of applications in the construction and agriculture industries. These motors will utilize the hydraulic pressure for driving mechanical loads. It is an important part of any hydraulic system along with hydraulic pumps, cylinders, valves, filters, seals, etc.
The design and construction of both hydraulic pumps and motors are similar. But the functions they perform are distinct. The hydraulic pump will pressurize the fluid drawn from the reservoir and will pass it to a hydraulic motor through the circuit for developing torque and rotary motion. Most of the hydraulic motors are interchangeable with hydraulic pumps. Those type of motors can perform functions like converting mechanical energy to hydraulic and hydraulic energy to rotary motion or torque.
In general, hydraulic motors are rotary actuators that provide the force and supply the motion to move an external load. Fixed or variable displacement motors that operate bi-directionally or uni-directionally are available in the market. Hydraulic motors are rated by its displacement and torque.
Hydraulic motors are classified into two based on its torque and rotational speed: Low-Speed High Torque(LSHT) and High-Speed Low Torque(HSLT). 0.1 to 1000 revolutions per minute is the speed limit of LSHT motors and 1000 to 5000 revolutions per minute is the speed limit of HSLT motors. Vane motors, gear motors, and piston motors are important subcategories. Vane motors use a vane to produce mechanical energy. This HSLT unit has features like low noise level, low flow pulsation, high torque at low speed, ease of vertical installation, etc.. Gear motors are low cost and lightweight motors suitable for handling a wide range of temperature, speed, and pressure. Piston pumps are suitable for applications requiring higher speed and higher efficiencies.
Also, Read: How Hydraulic Pump Works
Hydraulic Motor Applications
Almost every equipment utilizing hydraulics will have a hydraulic motor in it. They are important for moving or lifting heavy loads by converting hydraulic energy to rotary motion. Heavy earth moving equipment like excavators, skids, forklifts, heavy dumper trucks, bulldozers, etc.. work based on the extension and retraction of hydraulic cylinders. Hydraulic motors that transmit linear power are these cylinders. The high torque at low-speed operations of hydraulic motors made it suitable for heavy construction equipment like loaders. Compact and efficient hydraulic motors are suitable for operations like boring, reaming, drilling, etc.
Some other hydraulic applications are listed below;
- Oil pipeline inspection equipment
- Milling and sawing applications
- Drill and tap machine tool
- Marine and offshore applications
- Mining applications
- Tannery machines
- Wind turbines
- Injection moulding machines
Also, Read: Types of Hydraulic Cylinder
How to Select Hydraulic Motors
Hydraulic motor selection is a crucial step for every hydraulic professional. It is not so easy, because you need to choose one suitable for your application from the wide varieties. So, some important hydraulic motor specifications that you need to consider while purchasing a motor are listed in this section.
Not all motors are designed to suit all fluids, atmospheric conditions, pressure, speed, etc.. Each parameter will vary based on the selected motors. The important factor that one must consider while selecting, is the performance needs of the application. The maximum speed, flow, temperature and pressure requirements of the application are other key factors to consider. You need to choose a hydraulic motor that reduces the risk of installation and maintenance and also with reduced contamination potential.