Linear actuators are one of the vital parts of many mechanical components nowadays. These convert rotational motion into reciprocating motion, usually used in machine tools, industrial machinery, and in many other places where linear motion is necessary. Utilizing linear actuators are more efficient due to safe and clean motion control.
There are two distinct capacity load variables in operating Linear actuators: static and dynamic load capacity. Dynamic load capacity is referred to as the amount of force exerted while the actuator moves or is in motion. Static load capacity is referred to as the exerted force while the actuator is not moving or motionless. Another difference between actuators is their stroke, which can easily determine by the length of the lead screw and shaft.
Electrical linear actuators use stepper motors coupled to a series of gears and a lead screw that forces the primary rod shaft. The difference between them is usually determined by the load capacity and the size of the motor.
The actuator's operation is very simple; the motion starts with the turning of the screw, known as the lead screw, the rotation is either clockwise or counterclockwise. This causes the nut on the screw to create a push or a pull motion called linear motion.
The actuator's power supply comes from a DC or AC motor. The commonly used motor is 12v DC; however, many voltage ranges are available depending on the applications. Actuators have a switch capable of reversing the motor's polarity, causing the actuator to change its motion. The speed and force of the actuators will depend on the specifications of the gearbox.
Basic Parts of Linear Actuators
Power Source
A commonly used power source is electricity. Some actuators are operated using air (pneumatic) and fluid (hydraulic).
Power Converter
Responsible for supplying power from the power source, which is usually regulated by a controller.
Actuator
The main device.
Mechanical load
Dynamic and static load, Dynamic load is the force exerted when moving, Static load is the force exerted when it is stationary.
Controllers
It allows the operator to manipulate the system, change settings, and input quantities and setpoints.
Types of Linear Actuators Used in the Industry
Mechanical Actuators
Mechanical Actuators are the simplest type of actuator that converts one motion, such as rotary, into another kind, such as linear motion. Conversions are usually executed through simple types of mechanisms: Screw, wheel and axle, and cams.Hydraulic Actuators
Hydraulic Actuator or Hydraulic Cylinders consists of a hollow cylinder having a piston inserted in it. It uses incompressible fluid to produce unbalanced pressure on the piston and provide linear displacement of the piston. In Hydraulic Cylinders, the displacement only varies along the axis of the piston.
Pneumatic Actuators
Pneumatic Actuator or Pneumatic Cylinders are relatively similar to Hydraulic Cylinders, except instead of using incompressible fluid, Pneumatic Actuator uses compressed gas to provide pressure. Pneumatic actuators are not advisable to be used for heavy-duty machinery and instances where large weight is present. Usually, pneumatic actuators are used in the medical industry.
Piezoelectric Actuators
Piezoelectric Actuators use the piezoelectric effect. This effect is the capability of a material to produce an electric charge when mechanical stress is applied. Piezo actuators have different components of piezo elements, such as ceramics. The combination of different components results in an expansion that creates movement.
Coiled Actuators
Coiled actuators consist of magnets that produce a magnetic field. Magnetic fields are created by moving electric charges, wherein it generates current to move to a coil that will then create a motion in the shaft or shuttle. The higher the current produced, the higher force of motion produced.
Electromechanical Actuators
The distinction of electromechanical actuators from their mechanical counterpart is that they are cranked/ operated with an electric motor. The rotary motion of the motor is converted into linear motion of the actuator. Electromechanical actuators are programmable, wherein the force exerted can be changed using the computer.
