L i n e a r
M o t i o n
For linear roller bearings: =
√
10 3
1
10
(| 1 | 3
1
10
+ | 2| 3
2
10
+⋯+| |3
Where Fm = mean equivalent dynamic load F1 … Fn = load during each phase L = total travel over the move cycle L1 … Ln = distance traveled during each phase
This BSHP ball-runner block from Rexroth has a special run-in zone and more load-bearing balls in the load zone that other designs. Interchangeable into existing profiled-rail applications, the block also has dynamic load capacities 26% higher than previous designs — with static load capacities to 50% higher. Higher dynamic values make for service life that’s to 200% longer.
Linear Motion 5-17_Vs5.LE.LL.indd 61
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Note that every discreet load is multiplied by the distance traveled while that load is applied — and the whole equation is divided by total travel. This expression converts travel during each discreet phase to a percentage of total travel. For example, if an application has three different loads and travel with F1 is 100 mm, then travel with F2 is 300 mm and travel with F3 is 100 mm. So F1 is carried for 20% of the travel, F2 is carried for 60% of the travel, and F3 is carried for 20% of the travel.
5/4/17 4:49 PM