Single nuts can be preloaded by ball oversize, which results in a 4-point contact. This sets them apart from all other nut designs and has an impact on technical data.
4-point contact influences the kinematics of the balls with the following results:
- Efficiency of a single nut with preload is always somewhat lower than that of a double nut
- Single nuts with preload show a more pronounced reaction to manufacturing tolerances, which is why they are normally not suitable for very long screws
Caution: these statements are only true for single nuts with preload. Without preload, single nuts have 2-point contact with the same ball kinematics as double nuts!
Advantages of the single ball nut are:
- Cost effectiveness
- Compact envelope
- No unloading of balls when subjected to peak loads (see preload chart)