Like hydraulic cylinders, hydraulic motors are essential components that transform fluid energy into mechanical energy. By utilizing the flow and pressure from a pump, they provide the necessary power to drive various types of machinery. When high-pressure fluid enters a hydraulic motor, it pushes internal parts like gears, vanes or pistons to rotate the output shaft and generate torque. While motors provide continuous rotation, hydraulic cylinders are used for linear operations, such as pushing and pulling.

What Are the Different Types of Hydraulic Motors?

Hydraulic motors are categorized into four primary types based on their construction: Orbital (Gerotor) motors, Axial Piston motors, Radial Piston motors (star-like shape), and Gear motors. The choice between these types depends on the specific requirements of your system, such as the desired speed, pressure range, and torque output.

Orbital Motors

Orbital motors, such as the CML BMM, BMP, BMPH Series, operate on an internal planetary gear principle. The design consists of a fixed stator and a rotor with one less tooth. As high-pressure oil enters the motor, the pressure difference drives the rotor in an orbital motion within the stator. This mechanism makes orbital motors the premier choice for applications requiring high torque at low speeds.
Advantages: High starting torque, smooth low-speed operation, and direct drive of heavy objects without the need for a speed reducer (Gearbox).
Applications:Conveyor belts and automation equipment, Winches and hoisting systems, Agriculture, forestry, and fishery machinery, Logistics and material handling solutions, Construction and engineering vehicles, Wheel/track drive and cooling fan systems, Municipal and special-purpose vehicles.

For those seeking value, CML’s BMM Series Orbital Motors deliver exceptional quality at a competitive price. Ideal for low-speed, high-torque tasks and suitable for all the applications mentioned above, the BMM, BMP, BMPH Series ensure a perfect fit for your machinery.

Axial Piston Motors

Axial piston motors utilize pistons aligned with the output shaft to drive a swashplate, generating rotation. Known for their ability to handle high pressures (up to 350~450 bar) and high volumetric efficiency, these motors are highly responsive and offer impressive power density. They are the essential drive component for high-pressure, high-power applications like heavy-duty excavators and industrial injection molding equipment.

Radial Piston Motors

Radial piston motors feature pistons distributed in a radial pattern that move perpendicularly to the drive shaft. When hydraulic oil pushes the pistons against a waved cam ring, tangential forces are generated to produce rotation.
Due to its long internal stroke and large contact area, it can maintain extremely high torque output and smoothness at very low speeds (even below 1 RPM), and is commonly found in maritime winches, heavy lift cranes, and industrial machinery requiring extremely high starting torque.

Gear Motors

A gear motor consists of a pair of meshing drive and idler gears mounted within a robust housing. As high-pressure oil acts on the gear surfaces, it forces the gears to rotate in opposite directions.
Due to its straightforward design, this motor is lightweight, cost-effective, and offers a remarkably high tolerance to fluid contamination. While its efficiency and noise levels at high pressures may not match those of piston motors, its ease of maintenance and high-speed capability make it the ideal choice for fan drives, lawnmowers, and various low-to-medium pressure power assistance applications.