If you need to drive a 500kN axial load, 1500mm of travel, do you use a roller screw or a ball screw?
If you instinctively say roller screws, you may not be familiar with high-capacity ball screws as an economical and simple option.
With size constraints, roller screws have been promoted as the only technology option to handle large loads.
But in fact, technological advances have made special ball screws a candidate for high-load applications. The important thing is that a high load ball screw is usually half the cost of a roller screw with the same performance.
What’s the difference?
A ball screw consists of a threaded metal shaft and a nut that moves along the shaft as the motor drives the shaft to rotate.
Depending on the application in industrial automation, the nut is attached to a table, robotic arm or other load. Steel balls circulating within the nut contact the threads and provide load bearing. The coefficient of friction between components is very low, which often increases system efficiency to over 90%.
Therefore, the load capacity of a ball screw is a function of the diameter of the balls, the number of balls, and the surface contact area. The combination of these parameters determines the load capacity of the ball screw and also its service life.
In a roller screw, the load bearing member is a set of recirculating rollers rather than steel balls. The surface contact area of the roller is larger than that of the steel ball, which increases the bearing capacity and prolongs the service life.
But these benefits are relative. Compared with the simple and reliable ball screw, the roller screw requires more precise processing and more complex assembly in the early stage. This results in a higher overall cost of the roller screw and a larger size package for final installation.
Ball screw driven horizontal and vertical axes are used in large machining machinery to move heavy objects accurately and safely. Ball screws ensure long and reliable life with minimal maintenance. Such as machine tools, water jet cutting, plasma cutting machines and automatic welding machines.
Post time: Jun-09-2022
