Linear Motion Technology

Hidden champions of conveyor technology: five tips for selecting the right ball transfer units

Web Editorial Team Editor

2024.04.18. 10 min

Ball transfer units are true all-rounders. They ensure a reliable flow of materials in a wide variety of scenarios. With these five selection criteria, machine and system manufacturers can achieve optimum performance and service life with minimum maintenance costs.

Ball transfer units - friction coefficient diagram

1. Minimum friction

When it comes to selecting the appropriate ball transfer unit, it makes a big difference whether heavy loads such as cover plates or airport containers are moved or small objects are moved ergonomically by hand. After all, the ball transfer units should have minimal frictional resistance during material transport. These friction coefficients depend directly on the load and the required speed. As the conveying speed at Bosch Rexroth is consistently up to 2 m/s, the selection is very easy with the help of the friction coefficient diagrams provided throughout.

Various installation scenarios for ball transfer units

2. Installation position and fastening

Ball transfer units are typically installed with the rotating ball facing upwards. If the installation position is overhead, sideways or at an angle, the Rexroth ball transfer units work without any functional restrictions or loss of load capacity. There are also various mounting options. Ball transfer units can be pressed into bores, glued in or fixed with a tolerance ring. The ball transfer unit version with spring-loaded claws is particularly easy to install, as it can be fitted and removed very quickly and easily.

3. Ambient conditions

Ball transfer units work in all conceivable scenarios: indoors and outdoors, in a vacuum or in constant contact with dust, emulsions and other substances that place stress on materials. Oil-soaked felt seals, with which almost all Bosch Rexroth versions are equipped, protect against contamination. The ambient temperature can also influence the function of the ball transfer unit. It is therefore important to have a wide range of applications with regard to possible temperatures, without compromising the load capacity. Ball transfer units from Bosch Rexroth are suitable for the temperature range from -30 to 100 °C.

4. Required performance

Achieving the best possible performance requires binding manufacturer specifications in addition to high product quality. Life and service cycles can only be reliably determined with concrete values for load capacity and temperature. If the selected ball transfer units cannot remain in use for their entire service life, it is important to know when a planned replacement is due. The Rexroth product catalog provides a simple formula for calculating the individual service life for all types and sizes. This ensures productivity, minimizes maintenance costs and increases sustainability.

See for yourself!

To the Rexroth ball transfer unit catalog

Author: Christian Oppelt

Function: Product manager linear bushing and ball transfer units at Bosch Rexroth AG

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