An actuator is a component of a machine or device that aids in generating mechanical force by converting energy, frequently electrical, air, or hydraulic energy. It is the part of any machine that allows movement, to put it simply.
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What Is An Actuator?
In order to translate a control signal into mechanical motion, a device called an actuator must have some kind of power. Actuators are used in everything from ailerons on airplanes to electric door locks in cars. Actuators are used in industrial plants to control valves, dampers, fluid couplings, and other equipment involved in industrial process control. Electricity, hydraulic fluid, or air can all be used to power an industrial actuator. They are known as electric, electro-hydraulic, or pneumatic actuators.
Types Of Actuators
There are various types of actuators, each with a unique movement pattern and power source. Here is a list of the various types of actuators:
Electric Linear Actuator
Electric linear actuators, as their name suggests, use electrical energy to allow motion in a straight line. The majority of the movements they are used for include pulling, pushing, blocking, lifting, ejecting, clamping, or descending. They operate by moving a piston back and forth in response to electrical signals.
A motor that produces high-speed rotational motion and a gearbox that reduces the impact are the components of a linear actuator. As a result, the torque needed to turn a lead screw will increase, causing a shaft or drive nut to move linearly. In linear actuators, a 12V DC motor is frequently used, though other voltages can also be used. The motor would rotate in the opposite direction if the polarity of the connection from the motor to the battery were switched.
By varying the length of the shaft, manufacturers can provide linear actuators with various stroke lengths. You can achieve various speeds by using various gears. Generally speaking, the force decreases as the screw turns faster. When the screw reaches the end of its movement or stroke, a switch inside the main actuator shaft at the top and lower end stop it. The switch turns off the motor’s power when the shaft reaches its terminus.
Electric Rotary Actuator
Electrical energy is used by electric rotary actuators to produce rotational movement. As with servo and stepper motors, this movement can be either continuous or directed at a predetermined angle. An electric rotary actuator typically consists of an electric motor, limit switch, and multiple-stage helical gearbox.
The operation of this actuator can be stated simply as follows: When a conductor carrying current is brought within a magnetic field, it will experience a force that is proportional to the flux density of the field, the current flowing through it, and its dimensions. Due to the force and back electromotive force (EMF) that result, rotation, and torque are produced.
Hydraulic Linear Actuator
A hydraulic linear actuator serves the same purpose as an electric linear actuator, namely to produce a mechanical movement in a straight line. The distinction is that hydraulic linear actuators accomplish this by applying an uneven pressure with hydraulic fluid to a piston inside a hollow cylinder, which can result in torque powerful enough to move an external object.
A hydraulic linear actuator’s enormous torque capacity is its main benefit. This is due to the almost incompressibility of liquids. Piston motion is limited to one direction in single-acting hydraulic actuators, and reverse motion requires the use of a spring. A double-acting hydraulic actuator exerts pressure at both ends to enable comparable movement from both sides.
Hydraulic Rotary Actuator
Utilizing incompressible, pressurized fluid, hydraulic rotary actuators turn the mechanical components of a device. Rotational components typically come in one of two varieties: tables with a bolt pattern for mounting other parts or circular shafts with keyways.
They come in both single and double-shaft options. When the helical spline teeth on the shaft make contact with the corresponding splines on the piston, rotation of the shaft occurs, effectively converting linear motion to rotational motion. The piston rotates inside the housing as a result of fluid pressure, which causes the splines to turn the shaft. When a control valve is closed and fluid is kept inside the housing, the shaft can be locked in place.
Pneumatic Linear Actuator
The simplest and most affordable actuators are frequently regarded as pneumatic actuators. In order to move objects, pneumatic linear actuators use compressed air to move a piston, a carriage that rolls along a driveway, or, less frequently, a cylindrical tube. Using a spring or by supplying fluid from the other end, the piston is forced backward.
The best linear actuators for high speed and torque on a relatively small footprint are pneumatic ones. Quick, point-to-point motion is their strength and they don’t easily get damaged by hard stops. Because of their toughness, they are frequently used in equipment that needs to be resistant to harsh conditions like high temperatures or be explosion-proof.
Pneumatic Rotary Actuator
The oscillatory motion is created by pneumatic rotary actuators, which use compressed air. These are similarly straightforward in design, enduring, and appropriate for use in hazardous environments as pneumatic linear actuators.
Rack & pinion, scotch yoke, and vane design are three of the most popular configurations for pneumatic rotary actuators. In a rack and pinion configuration, compressed air pushes a piston and rack in a linear motion, which in turn causes rotary movements in a pinion gear and output shaft. There may be single, double, or multiple racks available for these.
Piezoelectric Actuators
When a mechanical force is applied, a class of solids called piezo materials, such as ceramic, respond to the electrical charge by expanding or contracting and releasing energy. Piezoelectric actuators use the movement brought on by electric signals to produce brief, high-frequency, and quick-response strokes. The movement that piezoelectric actuators produce is often parallel to the electric field. The movement is sometimes orthogonal to the electric field when the device is programmed to operate on the transverse piezoelectric effect, though.
Everyday Examples
An actuator is, to put it simply, a tool that causes something to move or function. We all use actuators on a daily basis—at least one of us does. Let’s examine some actuator examples.
1. Grocery Store Door
The door opens for us automatically when we enter the grocery store. The door opens using an actuator.
2. Car Seat
Prior to starting our car, we can move the seat forward or backward. The seat can be adjusted using an actuator.
How To Select A Linear Actuator
Actuators have numerous uses in a variety of industries, as we have already seen. All actuators, however, are not created equal. You ought to be able to determine which actuator best meets your needs before making a purchase. This detailed guide will show you how to select the ideal actuator for your requirements.
Step 1. Assess the movement required:
Does the object you need to move for your project require rotary or linear movement? While rotary actuators produce circular motion, linear actuators are useful for applying a mechanical force that would move an object in a straight line.
Step 2: Consider the energy input:
Due to their growing sophistication and versatility in handling a variety of operations, electrical actuators are growing in popularity. However, that does not imply that it is appropriate for all works available. If your work does not require electrical voltage input, think about hydraulic or pneumatic actuators.
Step 3: Assess the precision level required:
Some actuators work well for heavy-duty tasks in challenging environments, but they might struggle with smaller tasks like packaging that call for accuracy and the capacity to repeat the same action hundreds or thousands of times.
Step 4: Find out how much force you need:
An actuator’s function is to move or raise a target. Find out how much this object weighs in your situation. The amount that an actuator can lift depends on its load capacity, which varies even though many actuators may have a similar appearance. Ensure that the weight of your object and the actuator’s capacity match before purchasing an actuator.
Step 5: Find out how far you need the object moved:
It matters here how far you travel, or how long your stroke is. Your object’s motion is limited by the stroke length. Actuators with different stroke lengths are frequently sold by manufacturers.
Step 6: How fast do you want the movement to be:
Depending on the project, the actuator’s speed is frequently a crucial consideration for most people. Projects that demand high force output from actuators typically progress more slowly than those that produce low force. In distance per second, an actuator’s speed is expressed.
Step 7: Consider the operating environment:
Is there a need for the actuator to operate in a challenging or harsh environment where humidity or dust is a concern? You should pick a product with a higher protection rating if this is the case.
Step 8: Decide on the mounting style:
Before purchasing an actuator, it is important to understand the advantages of the various mounting options available on the market. For instance, a dual-pivot mounting method in a linear electric actuator allows the device to pivot on both sides while extending and retracting. This gives the application two free pivot points while following a set course.
On the other hand, stationary mounting, which fastens the actuator to an item along the shaft, is helpful for actions like pressing a button. You ought to be able to reduce your selections at this point to a much smaller pool than when you first started. You must further focus your efforts after this. For instance, there are numerous designs of linear actuators available for various uses. The most popular and straightforward among them, the rod-style, has a shaft that can be expanded and contracted. When there is a concern about space, a track style that does not change in size or length overall while in use is better suited. Additionally, column lifts and other actuators would be perfect for constructing TV and table lifts. Considerations like operating voltage and motor type may also be important.
Capabilities Of A Linear Actuator
Performance metrics are quantifiable results that assist you in assessing the caliber of a specific product. Actuators can be categorized under a number of performance metrics. Historically, torque, speed, and durability have been the most popular ones. Nowadays, energy efficiency is valued on par with other factors. Volume, mass, operating conditions, and other variables may also be taken into account.
Torque or force
Naturally, one of the key factors to take into account when evaluating the performance of an actuator is torque. A key factor here is to note that there are two kinds of torque metrics to consider, static and dynamic load. The capacity of the actuator at rest is referred to as the static load torque or force. The dynamic metric refers to the device’s torque capacity when it is in motion.
Speed
The speed of an actuator differs depending on the weight of the load it is supposed to carry. In general, speed decreases as weight increases. Therefore, it is best to look at the speed metric when the actuator is not carrying any load.
Durability
The durability of an actuator is determined by the type of actuator and the manufacturer’s design. Although hydraulic actuators are thought to be more robust and durable than electric actuators, the manufacturer will determine the exact specifications regarding the quality of the material used.
Energy efficiency
With increasing concerns about energy conservation and its direct impact on operational costs, energy efficiency is becoming more and more a decisive metric in all kinds of machinery. The amount of energy an actuator needs to accomplish its task in this case should be as low as possible.
How To Connect Linear Actuators
Different techniques are used to connect actuators to the control because there is such a wide range of actuators available. An electric linear actuator can be connected in a fairly straightforward manner. These days, a lot of electric linear actuators have four pins, and connecting them is as easy as plugging them in. In contrast, the procedure is slightly different if your actuator does not have four pins. A second connector, which is typically available in 6- and 2-foot lengths, will be required to be purchased.
Prepare the wires
There may be wires exposed at the end of your actuator. If necessary, you can slightly strip this back before connecting to a 4-pin connector. You should also strip back the connector’s wire if it is not exposed enough.
Connect the wires
Connect the linear actuator to the 4-pin connector by twisting the right exposed wires together and covering it up with electrical tape. Often the wires on the actuator and connector come in blue and brown colors and they can be connected accordingly.
The colors on the actuator might occasionally vary. Connect the brown actuator wire of the actuator with the red wire, and the blue wire with the black wire, for instance, if the actuator has red and black wires. If it comes with red and blue, connect the red to the brown and blue to the blue wire on the connector. Red and yellow actuator wires should be connected to the brown wire and yellow to the blue wire, respectively.
All set
Right now, you can start. Connect your device, then plug the control panel into the power outlet. Click here for a more comprehensive guide on connecting an actuator to a connector in case you encounter problems despite this.
How To Mount A Linear Actuator
The task of selecting an actuator and properly connecting it is only half completed. The actuator must be mounted in a manner appropriate to your application, which is equally important. Following are two popular ways to mount an electric linear actuator.
Dual pivot mounting
With this technique, an actuator is fixed on both sides with a mounting point that can pivot. This mounting point is typically made of a mounting pin or a clevis. The application can achieve a fixed path motion with two free pivot points by using dual pivot mounting, which enables the actuator to pivot on either side as it extends and retracts.
The ability to open and close doors is one of this method’s most practical uses. When the actuator extends, the dual fixed points enable the door to swing open. The action of the door closing and opening causes changes in angle, but the pivot provides ample space for the two mounting points to rotate. When employing this technique, make sure the actuator has sufficient space and is not blocked from extending by anything.
Stationary mounting
In this method, the actuator is mounted in a stationary position
Summary
Let’s go over what we talked about.
– A tool that causes something to move or function is known as an actuator.
– An Actuator can move something in a straight line, referred to as linear, or in a circular motion, referred to as rotary.
– An actuator utilizes energy from a source to move objects. It transforms the energy source into physical-mechanical motion, to put it another way.
That source of energy can be in 3 different forms:
– Pneumatic
– Electric
– Hydraulic
We sincerely hope you found this Actuator article to be interesting.
