Types of Electric Actuators, What are they and how are they different from each other.
There are several different types of Actuators you need to know about before selecting the ideal one for your application. Electric Actuators are a suitable alternative to pneumatic or Hydraulic actuators because they don't need all the extra equipment that needs to go along with each of those, they are also maintenance-free and provide simple, clean trouble free operation, and are highly controllable. These types of actuator last a long time and are very versatile. plus they are available in many different speeds, forces and strokes.
If you want to know the basics of an Actuator, please read our article dedicated to just this topic.
Within the Electric actuator rage there are many different type, each with their own unique qualities, benefits and of course downsides. Typically is the application that dictates the type of actuator you need to use. Lets explore the different types:
Parallel Drive Actuator
This Actuator style is called Parallel Drive, because it means the Motor sits parallel with the main Leadscrew which makes the Rod slide in and out. This type of Actuator style means that the Gear system inside the actuator uses a Spur gear or spiral gear drive mechanism to drive the leadscrew. The advantage of this drive style is that many different gear ratios are possible without having to change very much to the overall Actuator design. In fact its normal to have exactly the same housing of the motor and drive gear box never need to change and only the gears have to change in order to achieve different forces and speeds of the actuator. The downside is that when using spur gears on this style of actuator, they tend to be on the noisier side.
Some examples of Parallel Drive Actuators are shown below.
Right-Angle or L-Drive Actuator
With Right-angle Actuators, the main drive motor is set perpendicular to the Main drive shaft (Leadscrew). Therefore the driving force has to be transferred 90-degrees, and the only way to do this is by using a worm gear drive mechanism. One of the main positives for using a worm gear drive system is that they are very quiet. Unlike with spur gears where a majority of the noise comes from the gears, in an Actuator that uses a worm gear drive system, the noise from the gears in extremely quiet, thus the motor noise becomes the main noise source for this type of actuator.
Other benefits include the self locking feature which means these actuator styles are very hard to back drive. But creating different gear ratios can me a little harder, in fact there is a limited number of gear ratios possible with a Right-angle L-drive actuator type.
Some examples of Right-angle L-Drive Actuators are below
With an In-Line Actuator, the motors and drive mechanisms are all placed on the same center line as the main drive shaft (Leadscrew). Thais main design change allows for the actuator to be symmetrical is design and that offers the added benefit of having a cleaner aesthetic look to it. One of the downsides is the the Actuator typically will need to be longer because the motor and gear box need to sit behind the main drive shaft, instead of at the side. So when you decide to use an in-line type actuator, remember to account for the longer lengths compared to any other style of actuator you may consider.
Here are some examples of In-line Actuators:
With a Rotary Actuator, the final drive motion is rotary instead of Linear. One way to think of a Linear Actuator is that its basically a rotary Actuator with a Leadscrew and drive nut and Rod. After-all the leadscrew basically converts rotary motion from a rotary actuator into linear motion via the leadscrew. Therefore the driving motion in rotary actuators are continuous in either direction. Their are no stops or limits to stop a rotary actuator unless you give it a stopping component to make it stop. Typically people use Rotary actuators and attach something to the driving flange to create a motion they need in their final application. These types of actuators are very versatile and the only thing you need to consider is the torquer and speed required. It is worth remembering that in rotary actuators, the motion been rotary means the force is angular, so they are specified selected based on a torque dimensions and speed. Also remember that in these types of actuators, torque and speed trade-off against each other. So you can have high torque but the speed will be lower. If you need high speed, then you need to settle for less torque. This is due the the way gear ratio's work, not just for rotary actuator but in any type of motion where there are gears that sit in-between the driving motor and the final driving wheel.
Here is an example of a Rotary Actuator
Track Actuator (Slide Actuator)
This type of Actuator does not have a Rod or shaft that slides in and out of the end of the Actuator. Instead it has a carriage that slides along the main body or track of the actuator. These Actuators are quire different and are ideal for very specific applications. They are commonly used in Massage chairs and also in industrial assembly line type applications where the Track will slide something in and out repeatedly. The added benefit of these actuator types is that they are quite versatile with respect to the installation. The carriage or Nut as they are sometimes called have various threaded holes so you can easily attach things to them. Its also possible to have more than one carriage installed on the same track for greater strength and rigidity.
Here is an example of Track Actuators (Slide Actuator)
Electric Lifting Column Actuator
An Electric Lifting Column has the benefit of been able to lift long strokes whilst maintaining a compact closed length size. This is because column lift actuators have multiple stages inside of them, so they act as a telescopic actuator. This makes them great for Kitchen appliance lifts, podium lifts, hospital and office type lifts and desk lift applications. These types of actuators are also sturdier because they can handle side-loading which most other types of actuators cannot. A great example of electric lifting column if for use as a sit-stand desk lift, where each corner of the desk has one of these lifting columns installed and all 4 would work together to make the desk top lift up and down and all synchronized. Of course not all applications need more than one Lifting column, many applications are able to work fine on their own. A great example of a lifting column Actuators if in the use of a TV Lift from a cabinet. Fot TV Lifting, its important to have a short closed length when the TV is dropped into a cabinet, but be able to have a long stroke so larger TVs can clearly lift above the cabinet they are placed inside of.
Here is an example of a Lifting Colum.
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How to choose the ideal actuator