Static Safety Factor
To calculate a load applied to the ball spline, you must first know the average load used to calculate the service life and the maximum load used to calculate the static safety factor.
In particular, if the system starts and stops frequently, or if impact loads are applied, a large moment load or torque caused by overhung loads may be applied to the system. When selecting a model number, make sure that the desired model is capable of handling the required maximum load (whetherstationary or in motion). The reference values for the static safety factor are shown in the table below.
| fs | Static Safety Factor |
|---|---|
| C0 | Basic static load rating * (N) |
| Pmax | Maximum applied load (N) |
| fT | Temperature factor (see Fig.1 on Predicting the Service Life ) |
| fC | Contact factor (see Table8 on Predicting the Service Life ) |
* The basic static load rating is a static load of a defined direction and size where the sum of the permanent deformation of the ball and that of the rolling groove at the contact area under maximum stress is 0.0001 times the ball diameter.
| Machine using the Ball Spline | Load conditions | Minimum reference values |
|---|---|---|
| General industrial machinery | Without vibration or impact | 3.0 to 6.0 |
| With vibration or impact | 4.0 to 7.0 | |
| With vibration or impact under combined loads | 5.0 to 8.0 |
* The reference values for the static safety factor may vary depending on the load conditions as well as the environment, lubrication status, precision of the mounted surface, and/or rigidity.
