What do linear actuators and peanut butter cups have in common? It was only a matter of time until someone thought to combine the rich flavors of chocolate and peanut butter into a single, delicious, bite-sized snack.
That same mindset also brought about the melding of linear guides and linear actuation. Actuators make use of components that convert rotary motion (provided by a couple motor) into linear motion.
However, as these assemblies only accomplish the task of linear thrust, linear bearings such as guides or bushings, are incorporated into the design to handle any non-axial loads that the payload would impose. Through the combining of these technologies, linear actuators offer load bearing rigidity, as well as a smooth translation.
Two of the most common components for a linear actuator are ball screw systems and belt and pulley assemblies. There are benefits and limitations to these components, so choosing the right component comes down to the specifications needed for the application.
Below is an overview of ball screws versus belt drives.
Ball screws offer superior positional precision and repeatability as they come in a variety of accuracy grades. They also generally have a higher friction resistance, meaning they are preferred for a vertical application when paired with a brake.
Additionally, ball screws win out on load capacity as they typically offer greater thrust than belt driven actuators in a similar envelope. Examples of ball screw driven actuators are MISUMI’s LX and LS series.
Belt drives may fall behind on load capacities and linear precision, but, depending on the application, do provide some advantages over their ball screw cousins. Belt drives are ideal in applications that require high velocities or very long strokes because they are not restricted by shaft deflection which can cause whipping issues in a ball screw.
While ball screws are usually capped to around 2.5 m/s linear velocity, belts can reach up to approximate 15m/s! Examples of belt driven actuators include MISUMI’s MSA series and some varieties of the RS series.
While both ball screws and belt-driven actuators are the most common, understanding the strengths and limitations of each is essential. For a deeper dive into strengths and limitations of each type, click here.
Beyond Linear Thrust
Linear thrust is only one function of a linear actuator. The other half of the actuator formula is made up of non-axial load capacity which is supplemented by linear bearings.
Actuators can be subject to a variety of radial and moment loads, and the configuration of the linear bearings inside will have a significant effect as to how well these loads can be distributed and handled.
For example, an actuator that makes use of two parallel linear rails with 2 guides on each, such as MISUMI’s KU series will have significantly higher load capacities than one that uses only a single bearing.
When it comes to choosing the right linear actuator for your next project, you have options. But at MISUMI, we understand that having more options can make the decision process more of a challenge.
We make it easy to quickly find and configure high-quality parts for your next project. Explore MISUMI’s catalog of linear actuators here.