The tube deflection system is a type of ball recirculation mechanism used in ball screws. In this system, after the balls have traveled through the load-bearing threads, they are returned to the starting point via a deflection system located outside the nut. This creates a closed ball circuit that enables continuous force transmission between the screw and the nut.
How Pipe Deflection Works
During operation, the balls roll between the raceways of the spindle and nut, transmitting the resulting axial forces with virtually no friction. After the balls have passed through the loaded section, they exit the threaded groove and enter an external return tube. There, they are transported—without transmitting any force—to the start of the ball circulation path and then reinserted into the raceway.
The distinctive feature of this design is the externally visible return tube, which is arranged along the nut body and handles the ball return.
Design Features
Rohrumlenkungen werden hauptsächlich bei Kugelgewindetrieben mittlerer bis großer Baugrößen eingesetzt. Durch die externe Anordnung der Rückführung kann der Kugelkreislauf vergleichsweise einfach aufgebaut werden. Die Umlenkung erfolgt über speziell ausgeführte Übergangsbereiche, welche die Kugeln sicher aus der Gewindebahn aufnehmen und wieder einführen.
Je nach Konstruktion können unterschiedliche Geometrien und Rückführsysteme verwendet werden, um Laufruhe, Belastbarkeit und Lebensdauer an die jeweilige Anwendung anzupassen.
Advantages of Pipe Redirection
- A robust design principle that has proven itself over many years
- Cost-effective manufacturing compared to complex high-speed deflection systems
- High load-bearing capacity even with larger nominal diameters
- Easy access to the feedback elements for maintenance and service work
- Reliable operation in a wide range of industrial applications
Disadvantages of Pipe Redirection
- More installation space thanks to the return pipe located outside the nut
- Limited suitability for very high rotational speeds and extreme dynamic requirements
- The nut has a larger outer profile compared to compact internal recirculating systems
- Often less suitable than internal ball recirculating systems in tight installation spaces
Typical Applications
Ball screws with tubular guides are used in a wide variety of industrial applications. These include, among others:
- Machine Tools
- Automation and Handling Systems
- Positioning Axes
- Packaging and Assembly Technology
- General Machinery and Plant Engineering
- Applications involving heavy loads and long travel distances
Comparison with Other Repatriation Systems
Compared to internal deflection systems or end-cover deflection systems, the tubular deflection system stands out primarily for its robust build and simple design. While modern internal recirculation systems are often designed for particularly compact configurations and high rotational speeds, the tubular deflection system offers advantages in terms of cost-effectiveness, durability, and ease of maintenance.