Actuator And Types of Actuators

An Actuator or actuating member is a part of a mechanical system that controls. It responds to a current, such as an electric motor, an elevator, or a pulley. In simple terms, it’s a “motion controller”. Actuators come in many forms, including belt-driven, fixed, and mounted directly on the shaft.


Some are powered by electricity, others by hydraulic, and others, such as screw pumps and lift tables, are powered by minute changes in pressure. As the name suggests, an actuator used in an electric current application is characterized by its ability to regulate the speed of a rotating motor.

For example, in an electric linear actuator, the speed of a motor is controlled via a variable pressure signal generated by a variable in-line actuator. The actuator supplies the signal, which is converted into a smooth and continuous motion, either through a shaft or belt, by using a power-stepped variable or non-step variable control.

These types of actuators are usually mounted in a shaft mounted on a truck or generator. They may also act as a reduction unit, converting the electric motor’s motion into a pulse shape.

Stepper actuators consist of a screw shaft with an electric actuator, and a variable or non-stepsister has driven spring. The screw rotates a geared member that interfaces with a fixed or variable actuator. Stepper and screw linear actuators are commonly seen in applications where high mechanical tension is required.

The two types of actuators – screw thread – are both susceptible to various common errors, such as improper lubrication, slow speed or slow operation, and slow performance, resulting in both higher costs and increased downtime.

Actuator Valves

An actuator valve is a mechanism for manually and automatically opening and closing a specific valve. Manual-operated valves usually need a person in attendance to manually adjust them using a geared or direct actuator valve stem. Most valves are either hydraulically operated or electronically operated.

In some instances, the hydraulic actuator valve is used as a safety device. Hydraulic actuators have two shafts that run parallel to each other. One of the shafts has a ball element that rotates. The ball moves up and down in the groove that is lined with the ball element of the actuator valve, thus opening and closing the valve.

The other shaft is non-rotating and has a seat. The seat can be moved up and down by hand or by a motor to open and close the valve, depending on whether the valve is a manual or hydraulic one.

Actuator valves come in various types, such as single true, double accurate, or parallel single genuine unions. Single-True Unions are those that can only lock in either position, while parallel single-true unions are those that are capable of locking and unlocking in both positions. The type of actuator valve you choose will depend on the type of valve needed and the application you need.

Types of Actuators

There are many actuator types, each with its unique characteristics. Some of which will be described below:

Rotary Actuators

As the name implies, a rotary actuator is an actuator that produces a rotary force or rotation. This force can be either applied to a system component (the mechanical actuator) or applied to an exterior component such as a moving body (the non-mechanical actuators).

This actuator is used to provide a controlled force by rotating the actuator to perform a particular action. The simplest rotary actuator uses a screw-threaded rod through a hole in the shaft of the electric motor. A thin steel cylinder, with the rotary movement of the rod, provides the torque.

To control the speed of the rod, a variable resistor is connected between the rod and the motor; this resistor increases or decreases the speed of the rod so that either constant force or torque can be applied to the shaft to change the amount of flow through the electric motor. These actuators are the most commonly used and are available in both hydraulic and electric rotary valve forms.

Hydraulic rotary valves are usually the preferred form as they are generally much more reliable than their electric counterparts. However, they are limited in terms of the angle of movement and the speed they can achieve; the rotary valve forms must be perfectly square for the total torque to be achieved.

Non-mechanical rotary actuators are often used to provide a controlled pressure on a moving surface. Common examples include pumps, turbines, excavators, and some kinds of water pumps. These systems generally use a fluid such as oil (as in a water pump) or some compressed gas such as nitrogen.

This allows the mechanical force generated by the rotary actuator to vary the pressure of the fluid being exerted, which is then amplified as the speed of the actuator increases.

Screw Actuators

Screw actuators are devices that apply torque to a screw or bolt. As the name suggests, the screw acts as the actuator, and the screw threads act as threads on the actuator shaft. Screws or bolts of all kinds can be fitted with actuators.

From nuts and bolts to fishing weights and water pumps, screw threads are used in various applications to enhance performance and efficiency. The essential purpose is to force a fixed shaft to move against a differential that is not in motion.

In the past, mechanical actuators were usually made of brass or steel with a screw thread in between the holes. As technology advanced, different materials were used to advance the actuator concept. With the advancement of screw thread technology. It was possible to produce high-torque screw threads that are stronger than brass or steel.

Some examples of screw threads include diamond and silicon. The latest innovation in screw actuator technology is Teflon-coated threads, which are nearly indestructible, making them the ideal choice for screw application.

The application of a screw thread is just like applying for any other screw. However, the screw threads must be carefully selected based on the application. Some screws are suited for a particular application, while others may not be suitable at all.

To ensure that the screw does not fail before its time. The screw should be designed carefully, and the application should be performed using a jack and a moderate supply of pressure.

Linear Actuators

Linear actuators, also known as strain Gages, are measurement devices that use a fixed length of spring to transmit electrical signals. This actuator is used to measure the strain on a given load and then calculate the voltage across the load.

For example, it measures the force applied when a weight is lifted and measures the amount of energy used to lift the weight, the capacitance measured across the load after the weight is lowered. The capacitance measured at the end of the lift, when the load is let up. To make this calculation a bit easier, you can imagine that the spring will only move as much as its weight without any external force acting on it.

These kinds of actuators used in a variety of different applications. The most common example of a medical actuator is the electronic weighing scales used in clinical and hospital laboratories. In these settings, the actuator is attached to a machine that weighs the patient or object and then attaches a digital register to the machine.

The register gives the current reading, which can compare with the average values stored in the machine to determine whether the patient is overweight, underweight, or has some other range of readings. Linear actuators can also be used in other environments outside of the laboratory.

For example, they are often used in electric motors for variable load systems. There are three different main categories of linear actuators available, including direct control actuators.

Pneumatic Actuators

There are two main categories of pneumatic actuators available on the market. The first category is the piston pump, consisting of a cylinder and piston rod that is rigidly mounted to a gear in the back and an arm with a rotor that is rotational at the front of the cylinder.

When the rod is rotated, the rotor imparts radial force upon the gear at the front of the cylinder. This force causes the piston to rotate, which reciprocates the force into the cylinder and produces hydraulic pressure. These types of pumps are commonly used in aquaculture, where high pressure is required.

The second group of pneumatic actuators consists of rotary cylinder actuators. These cylinder units are available as either a ring or a disk rotating in a cylinder and having a gear in the back that is rigidly mounted to a gear assembly. These actuation systems can also be fitted with ring gears.

The force that the ring gears produce is radial. And, therefore, the rotary cylinder units must be positioned close to the center of gravity of the system. The advantage of ring and disk rotary actuators is that the disks can have a higher stroke force than the ring gears; this higher force will allow the actuators to exert more significant hydraulic pressure.

The disadvantage is that the disks can suffer from poor axial loadings if they are not appropriately sized.
The third type of pneumatic actuator is the compressed air actuator (also known as axial flow or axial force). These actuators use a cylindrical cylinder with a piston within a housing; the actuators’ piston acts upon the compressed air inside the cylinder.

Electric Actuators

Electric actuators are mechanical devices that transfer energy between two points utilizing an electric current. An actuator is a mechanism for closing and opening a physical valve. Manually operated valves need someone to manually open them with gear or mechanical mechanism attached to both the valve stem and the valve itself.

The advantages of using electric actuators for control and automated control of mechanical processes is that they are extremely fast to install and use. They have very high availability, as there is a great deal of demand for them throughout various industries and various applications.

The high reliability of these devices, along with high fluid power, makes them ideal for controlling the flushing of wastewater from mines and pumping industrial fluid power. Electric actuators are available in various types such as wire wound, rope mounting, or belt mounting; each type has its own set of benefits that make them ideal for different applications.

Electric motors that can be activated through electrical resistors also make use of an actuator. There are also different motor mounting options, such as integral mount, screw mount, and pipe mount. All these varieties are engineered with different features that make them a practical choice for various industrial applications.

Hydraulic Actuators

A hydraulic actuator is a diaphragm-like mechanical actuator that exerts a non-directional force on a shaft using a pressure swing. It has numerous applications, especially in manufacturing machinery, construction equipment, and civil engineering. Hydraulic actuators are designed to have a linear or a rotary motion.

The forces applied to the actuator’s two chambers are analogous to the application of a screw thread through a tight bore. Meanwhile, a diaphragm in a rotary actuator is similar to the inner ring of an oil pump. As the force applied to the two chambers is identical to the force acting on the inner ring. The results is the same as a one-way rotary actuator. Hydraulic collocation, however, applies the concept of internal pressure to the two chambers through two rotors instead of a single screw pump.

A diaphragm and piston are placed inside a fluid motor that has an external rotation shaft. A diaphragm’s motion is controlled by the control valve, usually a solenoid or an overload detector. The piston’s motion is controlled by an operator, typically a hydraulic power distributor.

Mechanical Actuators

Mechanical actuators, also known as mechanical actuators, are devices that transform the mechanical rotary motions of the machine to the outside entrance, usually in a linear direction. The mechanical actuators available for the mechanical engineering fields are applicable mostly for the areas where the needs are high for linear movements like: linear positioning, elevation and arachnology.

The mechanical actuator is used primarily to provide mechanical support and application to the mechanical processes. It is important for both industrial and household applications to determine the importance of mechanical actuators in our daily life.

To understand the significance of mechanical actuators, it is necessary to know about their mechanism. As the name suggests these actuation mechanisms use the principles of electromagnetic induction. Which are usually referred to as the electromagnetic force.

The mechanical actuator uses an electric motor to move the wire around a shaft, and when the wire moves it creates a resultant electric motor movement. The concept behind these types of motors is based on the inherent potential energy of any moving object. The amount of potential energy is dependent upon the wire’s position. The mechanical actuators use two types of motors, the electric motor, and the magnetic motor.

Although there are many types of mechanical actuators used in industries today. The most common and important type is the screw mechanical actuator. A number of screws are fixed to the main article and it contains numerous balls with teeth on its surface.

You can also read about the Pyrometer

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