Static Safety Factor (SKR)
Caged Ball LM Guide Actuator Model SKR consists of an LM Guide, a Ball Screw and a support bearing. The static safety factor and the service life of each component can be obtained from the basic load rating indicated in "Rated load of model SKR" (see Table4 detailed information for each model numbers [load rating] ).
Calculating the Static Safety Factor
LM Guide Unit
To calculate a load applied to the LM Guide of model SKR, the average load required for calculating the service life and the maximum load needed for calculating the static safety factor must be obtained first. In particular, if the system starts and stops frequently, or if a large moment caused by an overhung load is applied to the system, it may receive an unexpectedly large load.When selecting a model number, make sure that the desired model is capable of receiving the required maximum load (whether stationary or in motion).
| fs | Static safety factor |
|---|---|
| C0 | Basic static load rating (N) |
| Pmax | Maximum applied load (N) |
* The basic static load rating is a static load with a constant direction and magnitude whereby the sum of the permanent deformation of the rolling element and that of the raceway on the contact area under the maximum stress is 0.0001 times the rolling element diameter.
Ball Screw Unit/Bearing Unit(Fixed Side)
If an unexpected external force is applied in the axial direction as a result of an inertia caused by an impact or start and stop while model SKR is stationary or operating, it is necessary to take into account the static safety factor.
| fs | Static safety factor |
|---|---|
| C0a | Basic static load rating (N) |
| Fmax | Maximum applied load (N) |
Standard Values for the Static Safety Factor (fS)
| Machine type | Load conditions | Minimum Static Safety Factor (fs) |
|---|---|---|
| General industrial machinery | Without vibration or impact | 1.0 to 3.5 |
| With vibration or impact | 2.0 to 5.0 |
* The standard value of the static safety factor may vary depending on the load conditions as well as environment, lubrication status, mounting accuracy, and/or rigidity.
