Static Safety Factor (SKR)
LM Guide Unit
During actual operation, damage may be caused by an unexpectedly large load acting on the LM Guide that is caused in particular by sudden starting and stopping or a large moment created by an overhang. Therefore, a static safety factor (fs) must be considered. The static safety factor (fs) is derived from the relationship between the applied load and the basic static load rating. The estimates for the static safety factor based on operating conditions are given in Table 8.
| fs | Static safety factor |
|---|---|
| C01 | 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)
For ball screws and bearings, a static safety factor (fs) derived from the relationship between the calculated maximum axial load and static load rating must be considered. Vibrations, impacts, or inertia due to starting and stopping may result in an unexpectedly large load. Therefore, please confirm that a sufficient static safety factor has been ensured when selecting a model. The estimates for the static safety factor based on operating conditions are shown in Table 8.
| fs | Static safety factor |
|---|---|
| C0a1 | Basic static load rating (N) |
| Fmax | Maximum applied load (N) |
Static Safety Factor (Guideline)
| Load conditions2 | Lower limit of fs |
|---|---|
| Without vibration or impact | 2 or greater |
| With vibration or impact | 5 or greater |
- 1 The basic static load rating is a static load with a constant direction and size where 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.
- 2 In general, factors that cause vibration and impacts include acceleration and deceleration, sudden starts and stops, transmission of vibration and impacts from external devices and machines, and changes in processing force over time.
