Design of the NUT

The main stress considerations in designing a power screw are: (for both nut and screw)

1. Bearing Pressure

2. Bending Stress

3. Shearing Stress

4. Tensile or Compressive Stress

5. Combined Stress

6. Buckling Stress

1. BEARING PRESSURE

The bearing pressure is the crushing stress between the surface of the screw thread and the contacting surface of the nut.

where = depth of the thread

= number of threads in engagement

Active Length of the nut ()

2. BENDING STRESS

3. SHEAR STRESS

4. Combined Shear and Bending Stress on the nut

5. Combined Axial and Torsion Stress on the nut

Compressive stress

Torsional Stress on the nut

6. Bearing Stress on the nut head

7. Shear Stress on the nut head

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