Thread flanks are the lateral surfaces of a thread turn located between the thread root and the thread crest. They are the load-bearing contact surfaces through which forces are transmitted between the spindle and the nut.
Thread flanks are crucial for:
- Force transmission: Axial forces are absorbed directly via the flanks of the nut and spindle
- Wear behavior: Surface quality and lubrication influence friction and service life
- Efficiency: Flank angle and friction determine the mechanical efficiency of the thread drive
- Accuracy: Uniform flank contact is important for spindle backlash and positioning accuracy
Properties
- Flank angle: Depending on the thread profile (e.g., trapezoidal, buttress, round or ball screw thread)
- Type of contact: Sliding contact
- Ball screw drives: Force transmission via balls between the flanks
- Load: Uniform flank loading reduces local stress peaks
Practical relevance
In precision or highly loaded thread drives, the thread flanks must be hardened, ground and well lubricated to minimize friction and ensure a long service life.