Introduction to Hydraulic Orbital Motors Offered by Impro Fluidtek - Impro Precision


Introduction to Hydraulic Orbital Motors Offered by Impro Fluidtek

January 17th, 2023

If patents signify technological mastery, the many held by Impro Fluidtek show an understanding of hydraulic orbital motors in ways few can match. Impro Fluidtek traces its roots back to White Drive Products, founded in the USA over 40 years ago, and is a leader in these motors. You’ll find them used in agriculture, forestry, construction, mining and manufacturing operations. They’re even used in casting processes like those carried out by Impro Precision.

About Impro Fluidtek Hydraulic Orbital Motors

Hydraulic orbital motors deliver high torque at low speed. This is achieved through a precision machined gerotor assembly, where a rotor gear rolls around the inner surface of a stator.

The rotor has one tooth less than the stator, which facilitates the rolling motion and divides the rotor cavity into two chambers. Pressurized hydraulic fluid delivered to one chamber pushes the rotor towards the other, low pressure, chamber. A valve moves the fluid delivery point around in a circle so the rotor is constantly pushed towards the rotating low pressure side, which creates the orbital motion.

An output shaft passes through and is geared to the center of the rotor. With this arrangement it takes multiple revolutions of the rotor to produce a single turn of the output shaft. The output shaft therefore turns relatively slowly, and this speed reduction multiplies the torque produced by fluid acting on the rotor teeth.

Product Range

Impro Fluidtek offers eight series of orbital motors for light, medium and heavy-duty applications. Each series is produced in a range of displacements that yield specific combinations of torque and speed. Motor specifications provide both maximum continuous and intermittent speed and torque ratings, with the intermittent ratings being significantly higher.

The four light duty motors are designated WD, WG, WP and WR. Designed for 173 – 207 bar (2,500 – 3,000 psi), maximum continuous speed ranges from 140 to 1,362 rpm and maximum continuous torque from 34 to 480 Nm (25 – 354 ft-lbs). A range of mounts and shafts are available for design integration flexibility.

Medium duty applications are addressed by the CE and RE/RC motors. These handle up to 241 bar (3,500 psi) and the latter models are intended specifically for low flow – high pressure environments.

The heavy duty WS 360 and WS 365/366 hydraulic motors come with multiple shaft and mounting options and heavy-duty bearings for increased resistance to side loads. Maximum pressure is 276 bar (4,000 psi).

Reasons for Using Hydraulic Orbital Motors

Hydraulic motors are intended for high torque and low speed applications where it’s undesirable or impractical to use electric motors. This could be because high voltage cables can’t be used or because mobility is needed. Advantages of hydraulic orbital motors include:

  • High torque from a small housing
  • Controllable output speed and torque
  • Reversible
  • Rugged and durable
  • Can eliminate complex transmission designs
  • Highly mobile (with a hydraulic power pack)


Hydraulic orbital motors are used in two situations: static applications found in industry, mining and agriculture, and mobile, vehicular applications like those in agriculture, forestry, construction, landscaping and logistics.

In industrial, mining and agricultural settings hydraulic orbital motors drive belt and screw conveyors carrying heavy loads or lifting material significant heights. They are also used in rolling mills, big injection molding machines and casting processes.

Mobile applications include powering vehicle motion, often through individual wheel motors, plus raising, lowering and actuating equipment like augers and spreaders. Skid steer machines used in landscaping and construction use hydraulic wheel motors for steering.

Cranes and scissor lifts are another group of mobile applications using hydraulic orbital motors. They are also found in various types of material handling equipment.

Meeting the Need for High Torque Rotary Motion

Rugged hydraulic orbital motors provide rotary power in remote and inaccessible locations and in factories and warehouses. With a history in these motors stretching back over 40 years, Impro Fluidtek has the range and experience to meet the needs of the most challenging applications. Contact us to learn more about our motors and our capabilities.


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