Screwjack effects of wear on thread stripping load
Purpose of calculation:
Calculate thread stripping load on ACME leadscrew
Determine effects of wear on thread stripping load.
This calculation is featured as a case study.
Check against manufacturers recommendations
Select Acme Leadscrew thread Size (dia. - threads per inch)
1) Leadscrew Dimensions
Outside diameter of thread
Inside diameter of thread
Manufacterer's (Roton) Static Load Rating
Manufacterer's (Roton) Operating Load Rating
Shear thickness per thread
2) Estimate wear allowance
Maximum clearance and wear allowed
3) Nut material properties and nut shear strength calculation
Calculated operating load
Correlation between calculated and manufacturers value
4) Calculate normal loading with maximum allowable load nut wear
Force on leadscrew
5) Calculate wear for nut thread stripping
Critical Clearance/Wear Limit for nut stripping
Amount of wear for nut stripping
6) Estimate Wear
Surface Hardness (Brinell Hardness in kg/mm2 convered to psi)
Wear Coefficients from ExcelCalcs Repository
Unlubricated wear depth in 6 months - Ref. Juvinall Eqn. (9.1)
Time to unlubricated load nut failure
Lubricated wear depth in 6 months
Time to lubricated load nut failure
Fundamentals Of Machine Component Design - Juvinall
Mechanical Engineers' Handbook
Schaum's Outline - Machine Design
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