Ball screw linear actuators
Ball screws get their name from the re-circulating ball bearings that fit between arch-shaped screw threads and corresponding threads in the nut. The ball bearings transmit force and relative motion efficiently as they roll through one or more circuits in the nut.
Ball screw actuators have higher thrust capabilities, longer service lives and higher efficiency than those with acme screw systems, but they can’t match the performance of roller screw actuators. Ball screw actuators can be back-driven and can be noisy. They’re ideal for applications that require high duty cycles, moderately high thrust and moderate speeds. They tend to be reasonably priced, making them popular in many applications.
When it comes to comparing roller screw vs ball screw of similar size and lead, a ball screw’s ball bearings have fewer points of contact than roller screws as shown in the diagram below.
This, plus a design that allows the bearings to contact each other, limits the ball screw’s DLR*, leading to lower forces and shorter life.
|Dynamic Load Rating
||Very Long, Many times greater than ball screw
|Relative Space Required
||None to Minimal
For most applications that require high force, repetitive cycles and long expected life, Tolomatic will recommend a roller screw linear actuator. However, if the force is lower and high continuous speeds are present in the application, Tolomatic may recommend a ball screw actuator.