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.
Calculation Validation
Check against manufacturers recommendations
Select Acme Leadscrew thread Size (dia. - threads per inch)
1) Leadscrew Dimensions
Outside diameter of thread
Thread Pitch
Inside diameter of thread
Manufacterer's (Roton) Static Load Rating
Manufacterer's (Roton) Operating Load Rating
Thread angle
Shear thickness per thread
2) Estimate wear allowance
Maximum clearance and wear allowed
Nut/collar thickness
Shear Area
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
Operating load
5) Calculate wear for nut thread stripping
Critical Clearance/Wear Limit for nut stripping
Amount of wear for nut stripping
6) Estimate Wear
Bearing stress
Rubbing Distance
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

Calculation Reference
Fundamentals Of Machine Component Design - Juvinall
Machinery's Handbook
Mechanical Engineers' Handbook
Schaum's Outline - Machine Design

Calculation Preview

28 Jan 2010
Last Modified
28 Jan 2010
File Size:
182.00 Kb
File Version:

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