Question
Download Solution PDFFor a power screw having square threads with lead angle of 45° and coefficient of friction of 0.15 between screw and nut, the efficiency of the power screw, neglecting collar friction, is given by
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFConcept:
The efficiency of the power screw:
\(\eta = \frac{{tan~α}}{{{\rm{tan}}\left(α + \phi\right)}}\)
where, ϕ = angle of friction, α = Helix angle or lead angle
Also, the coefficient of friction:
∵ µ = tan ϕ
Calculation:
Given:
µ = 0.15, α = 45°
As we know, the coefficient of friction:
µ = tan ϕ
tan ϕ = 0.15
ϕ = 8.53°
\(\eta = \frac{{{\rm{tan}}\left( {45} \right)}}{{{\rm{tan}}\left( {45 + 8.53} \right)}}\)
η = 74%
Last updated on Jul 2, 2025
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