MOTION SYSTEMS HANDBOOK
Calculating
linear bearing life When selecting linear guides, have you ever seen a disclaimer in the catalog or on the manufacturer’s website regarding dynamic load capacities? It typically reads something like this: Note that dynamic load capacities are based on 100,000 m of travel. When comparing to products whose load capacities are based on 50,000 m of travel, multiply the 100,000 m rating by 1.26.
If you saw this, you probably wondered where the 1.26 comes from and why it’s important. To find out, we’ll look at the bearing life equations for each rating to derive the conversion factor. But first, let’s review the difference between static and dynamic load capacity. Static load capacity according to ISO 14728 Part 2 is the force that causes permanent deformation of the rolling element (ball) and raceway, which equals 0.0001 times the rolling element diameter. This is an important specification because if it is exceeded, the running characteristics of the bearing will be compromised.
Motion Control Solutions from
LSM Series bit.ly/Config-LeadScrew
Compact Series bit.ly/Config-Compact
ML Series bit.ly/Config-ML
SIMO Series
PL
bit.ly/Config-SIMO
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Try Our New Configurators Today at pbclinear.com Linear Guide Rails & Slides & Ways — Motion Control HB 08-19 V3.indd 88
8/21/19 11:31 AM
