How to Choose the Right Hydraulic Actuator
Different actuator models typically depend on the system’s operating pressure. This is why it’s important to know the pressure required, along with other key factors including load capacity, rotation angle, rotation speed, and more.
Operating Pressure
First, determine the operating pressure. This is important to ensure the actuator is rated for the system pressure being used.
Torque
The amount of torque helps determine how the actuator will perform and how much it can handle, especially in terms of load capacity. The higher the torque output, the more load capacity the device will have.
Dynamic Movement
Next, determine if the rotary actuator will be used in highly dynamic applications, such as torque/torsion testing. If so, end-cushioning is important to have, along with a servo valve that can be mounted to the actuator to offer more control to the device.
End-Cushioning
End-cushioning is an important factor to consider for highly dynamic applications, such as when the actuator needs to function as an end stop in a load. End-cushioning acts as a hydraulic break to slow down the movement of the actuator so that it doesn’t slam into the end position causing damage to the device or the workpiece. The end-cushioning effect can be finely tuned using built-in orifices and set screws.
Mounting
Actuators can be mounted in different ways, along with different shaft styles. The actuator might have a flange mount, foot mount, or threaded holes in the actuator body. The shaft could be male or female with spline, key, or other shapes; as well as flange style.
Temperature
Typical hydraulic systems operate in an oil temperature range from -4°F to +240°F (-20°C to +60°C) in the same range. Actuators operate in the same range. If actuators need to operate above or below the standard temperature range, then special steels or special seal material may need to be used.
Mediums
The same applies to different mediums. Different mediums could require non-standard seals and different actuator materials.
Side Loads
If the application and actuator have side loads, the side loads need be absorbed separately from the actuator, or the actuator needs to be designed to accommodate the side loads. This is often done through the use of bearings. Eckart usually includes 4-point contact bearings as standard.
General Applications
Finally, it’s important to understand the general application. For example, will the device be going offshore? This might require special paint and special seals to protect the actuator from harsh seawater environments. As mentioned above, it’s important to know if the actuator will be used in testing applications, as special attention would be needed to make low-friction seals and a servo valve adapter plate.
