Linear Actuator Types

If you want to transfer a load from one point to another point in a controlled manner, in a machine, or in a place in your home that needs movement, you need electromechanical products. You can also do this yourself by purchasing mechanical products such as ball screws, belts/pulleys, or racks/pinions and combining them with a stepper motor or servo motor. But putting these products together may require a high degree of mechanical, electronic, and software knowledge. If you want to have a ready-made product, you can use linear actuators produced by many different companies.

Linear actuators are generally divided into two types, pneumatic and mechanical. Pneumatic actuators are more difficult to use because they cannot provide high precision and a compressed air line is required. For this reason, we will not examine the pneumatic types in this article.
Mechanical linear actuators are divided into 4 according to their drive method.
These types can be explained as follows;
Ball Screw type,
Rack-Pinion type,
Belt-Pulley type
Linear Servo Motor type.

Ball Screw Linear Actuator

Ball screw linear actuators are divided into two according to their working methods.
1- Linear Motion Guide Actuators
2- Rod Actuators
1- Linear Motion Guide Actuators
This type of linear actuator works with ball screw positioning between LM Guide products housed in a sealed aluminum body. They are used to change position by carrying the load instead of pushing the load to be moved. The LM Guide products used in the linear actuator determine the magnitude of the load and the moment values ​​it can create. Then, ball screw shaft diameter and pitch may be checked for axial movement requirements. I explained how to make these calculations in my previous articles. You can see 2 sample images showing the interior and exterior structure below. The picture showing the internal structure is a custom-made LM guide actuator. The one showing the outer structure is the GL series LM guide actuator of the THK brand.

2- Rod Actuators
Rod-type actuators usually have LM bushing bearings to support the lateral load. However, this type of actuator is not made to carry radial loads.
Radial loads must be carried with an external LM Guide. Rod Type Actuators are only used to generate axial force. Smaller ones usually come with a built-in DC motor. However, the types that require high thrust work with a servo motor and gearbox combination. You can see examples in the images and video below.

Rack-Pinion Linear Actuator

It has the same logic as ball screw-type linear actuators. Similarly, LM guide is used to carry the load in the aluminum body. In addition, rack and pinion linear actuators can also be used for gripper purposes.

Belt-Pulley Linear Actuator

If speed is needed in applications that require the use of linear actuators, belt-pulley types are the most suitable ones. The method of using LM Guide is the same as the previous types, but the pulley diameters are determined according to the speed requirement. It is the linear actuator type with the lowest positioning accuracy.

Linear Servo Motor Linear Actuator

It is the actuator type that includes the newest technology. The linear actuator does not contain any mechanical drive equipment. It makes positioning with the electromagnetic thrust force produced by the linear servo motor. In addition, a linear encoder is required to measure its position.

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