A driven nut is a special type of screw drive in which it is not the spindle but the nut that is rotated to produce a translational movement of the spindle (or the load attached to it).
Advantages
One advantage of this design is, for example, the elimination of the critical bending speed. As the spindle does not rotate, there is no upper speed limit dictated by the critical bending speed of a rotating spindle. However, the natural bending frequency must still be taken into account even with stationary spindles. The resonance scenario is less critical due to the low energy input from the driven nut.
Furthermore, radial and axial runout are optimised by the driven nut. This allows the system to be operated up to the maximum speed, which is determined by the speed rating. However, the natural frequency range should be passed through quickly to avoid placing unnecessary strain on the system.
The mass inertia is also reduced by this special nut. As the spindle does not need to be set in rotation, the mass inertia in the system is reduced. This enables a simpler and more cost-effective end bearing arrangement for the non-rotating spindle.
A further advantage arises from the compensation of temperature effects. The stationary spindle can be easily preloaded to compensate for changes in length caused by temperature effects, which are further minimised by the use of a hollow spindle with cooling.
Disadvantages
One drawback of this system is the motor, which has to be moved along with the table, requiring additional space and the necessary power supply.
Areas of application
- CNC machines
- 3D printers or handling systems
- Machine tools with high dynamic performance requirements
- Aktuatoren mit integriertem Linearantrieb