A deep dive into how the orientation of a linear ball bushing bearing affects its load capacity
To optimise linear ball bushing load capacity, you need to orientate your linear ball bushing bearing correctly in relation to the applied load. For maximum performance, the bearing should be positioned, so the load is distributed across multiple load-bearing tracks rather than a single track.
Using a polar graph to map ball bushing orientation against maximum load capacity, it is easy to understand the relationship between load direction and bearing performance. These load correction graphs are included in Thomson linear ball bushing bearing data sheets to help engineers optimise installation and maximise linear bearing load rating.
Here’s What the Graphs Tell Us
- Where the load is distributed across multiple bearing tracks, linear ball bushing load capacity is at its highest.
- Where the load is applied directly over a single bearing track, the load capacity is at its lowest.
What Do We Need to Do?
When the load is carried by only one set of bearing tracks, the linear bearing load rating should be derated. This can be achieved by changing the ball bushing orientation within the housing so the load is shared across multiple bearing paths. This is known as applying the correction factor for maximum load and is an important consideration during ball bushing selection.
What About Open Linear Bearings?
In most applications, it is not practical to rotate open-type linear ball bushing bearing assemblies because the shaft supports restrict movement.
However, understanding how load direction affects linear motion load capacity remains essential. Polar graphs show that downward loads acting onto the support rail behave similarly to closed bearings, while loads acting opposite the slot (attempting to pull the bearing away from the rail) significantly reduce the available load capacity. In some cases, these bearings can resist pull-off loads of only around 25% of their maximum rated load.
If in Doubt, Ask for Support
Optimising linear ball bushing load capacity is one of the most effective ways to improve bearing performance, extend service life, and achieve reliable operation. If you are unsure about ball bushing selection, bearing orientation, or load ratings, seek technical advice before installation.
Bowman stocks a wide range of Thomson linear ball bushing bearings. Contact our team for expert guidance on load optimisation, product selection, stock availability, and delivery times.
