One of the two most important design features that characterize ball screws is the ball return system (the other being rolled vs. ground shaft construction – more on that here).
Steinmeyer pioneered internal return technology. In fact, we’ve never used a tube! With tube returns, balls are forced to change direction, occurring twice – at each end of the tube – at an angle of 90 degrees. Such extreme motion causes higher frictional losses, increases the risk of ball jamming, and leads to higher friction torque variation. Another problem with tube returns is loss of lubricant. The port where the tube enters the nut body is very difficult to seal.
Our design philosophy for return systems is guided by one main principle: follow the natural trajectory of the ball. All Steinmeyer returns are based on tangential deflection – an approach that minimizes the required forces and results in higher efficiency and reliability.
You may have heard that internal returns are incompatible with rapid design and high volume manufacturing. We solved this challenge long ago with technology and engineering know-how. All of our deflectors are fabricated in-house by milling or by additive methods. Combined with modern CAD tools, we design and produce a variety of complex shapes in high volume for customers around the world.
It’s our firm belief that our internal return technology is second to none. It is being successfully used in many demanding applications in machine tools, aerospace, and other applications.
Frankly, we have yet to find an application where tube returns out-perform internal returns.