Spindle Shaft

Revision as of 21:09, 12 April 2007 by Martin (Talk | contribs)

Spindle Shaft Design, 7th April

Developed a model to predict the peak cutting force and shaft torque
Wrote a matlab tool (edited version below) to determine peak forces and bending moments in spindle shaft and bearings
Wrote a matlab tool to specify bearing from cutting force, torque, and desired life and reliability (via the Weibull Equation)
Specified a collet from sheets provided in lab
Used results from above tools and supplied lathe solid model to specify shaft dimensions:
- 30 mm shaft outer diameter, 50mm diameter for center section
- 10 mm inner diameter

Altered matlab tool to take into account fatigue at bearing A.
For a steel shaft, we have a slope factor of safety of 9, a stress factor of safety of 15. The stresses are an order of magnitude below the endurance limit, so fatigue should not occur anywhere in this shaft. (or, a lifetime of 10^10 minutes - about right according to Chris).
Assumptions - w_shaft = 570rpm, axial force = 100N, radial force = 240N, stress concentration at fillet = 2.5, assume 1020 steel which is pretty weak.
Endurance limit of 1020 steel = 210MPa, k_overall=0.75, Von Mises stress at Bearing A = 21.6MPa, and smaller at nut by rough calculation.