Off-Highway Power: Hydraulic Orbital Motors in Construction and Agricultural Machinery - Impro Precision


Off-Highway Power: Hydraulic Orbital Motors in Construction and Agricultural Machinery

February 5th, 2024

Mobile machinery used in construction and agriculture needs low speed and high torque rotary motion. For many such applications, the best way of achieving this is with hydraulic orbital motors. This blog explains why and looks at some examples of applications. First, though, is a short introduction to this motor technology.

Hydraulic Orbital Motor Basics

Hydraulic motors are an alternative to electric motors. They are driven by the flow of hydraulic fluid, and so need a pump and reservoir, plus a power source to drive the pump. This makes them a good fit with diesel-powered machinery where an engine can run the hydraulic system.

Hydraulic motors are similar in design and operation to pumps: one uses rotary motion to push fluid, the other uses moving fluid to produce rotary motion. An orbital motor is a specific type of hydraulic motor that uses a gerotor – essentially a gear within a gear – to turn an output shaft. Fluid from the pump acts on one side of the inner gear – the rotor – making it roll around the inner surface of the stator.

Torque from a hydraulic motor is proportional to fluid pressure and the surface area of the rotor teeth. This results in high torque output from a compact motor design. Rotation speed is low – typically 50 – 250 rpm – due to the reduction effect of the rotor-stator combination.

Environmental Considerations for Construction and Agricultural Machinery

Job sites and farms are tough places for mobile machinery. There’s a lot of dirt, dust, mud and water, and equipment will suffer random heavy impacts and high levels of vibration. Durability requires a rugged design that excludes water and grit while also resisting shocks and withstanding high loads.

Applications for Hydraulic Orbital Motors

The main classes of application in construction and agricultural machinery are:

  • Wheel motors
  • Positioning mechanisms
  • Driving rotary equipment

In construction, machines like road rollers, excavators, wheel loaders and backhoe loaders can all use hydraulic wheel motors. The compact size, high torque and low speed characteristics of orbital motors make them the ideal choice.

These same machines may use hydraulic orbital motors to move buckets and arms. Their high torque and low speed can eliminate the need for reducers, saving space, weight and cost.

Under the “rotary equipment” heading come cement mixers. Again, the hydraulic orbital motor has the ideal operating characteristics for this application.

“Agricultural machinery” covers a wide range of machinery, but the same considerations apply as for construction machinery. Skid steers and combine harvesters are examples of machines using hydraulic wheel motors. Planters, rotary tillers and sprayers are agricultural machines that can use hydraulic orbital motors to rotate and position arms, booms or other mechanical components. And lastly, augers, like those used for elevating grain, are often powered by compact hydraulic motors.

Impro Fluidtek Orbital Motors for Construction and Agricultural Applications

The Impro family of hydraulic orbital motors spans light, medium, and heavy-duty models. Many of the uses discussed previously are classed as heavy-duty, and Impro WS product line motors are more than up to the challenge.

These heavy-duty hydraulic orbital motors incorporate tapered roller bearings engineered for increased side load capacity. That ensures they can handle the forces experienced in wheel motor and positioning applications. They also use a heavy-duty drive link design that enables them to handle spikes in pressure and torque. In addition, to cope with the arduous conditions found on job sites and in fields, they are available with slinger seals that prevent material building up around shafts and finding its way inside.

Durable Design and Construction

Construction sites and farms are tough environments for mobile machinery. Only rugged, heavy-duty motors can survive in dirty, wet conditions where impacts and vibration are constant factors.

Impro Fluidtek hydraulic orbital motors are engineered to deliver the low speed and high torque needed and are more than up to the application challenges. Contact us for more information.


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