Lead screws need clearance between the screw and the nut to move. Backlash is the relative axial movement distance between the nut and the screw without rotation of either one. Backlash can increase with wear. If your system has no way to compensate for backlash, you could experience inaccurate positioning. One of the most effective methods to prevent backlash is through preloading of the moving nut. This is achieved through the use of Anti-backlash nuts.
Axial Anti-backlash nuts consist of a main nut body and a secondary ring that share the same thread form. There is a spring between the two components that force each part against opposing flanks of the screw thread. This remove the clearance between all the components i.e. gets rid of the backlash.
The precautions to this design is that if the load is greater than the spring force, you can still get backlash in the system. For a greater load you need a stronger spring to keep backlash to a minimum, however, a stronger spring means more friction between the nut and screw which requires more drive torque to overcome.
ACME (tarapazoidal) here means the type of the thread of the lead screw on which we mount the moving nut block.
- Pitch: 2mm
- Lead: 8mm
- Material: Brass
- Thread Type: ACME (Tarapazoidal)