Design of Flexible Coupling

Design of Flexible Coupling.

Design of Shaft.  The shaft Undergoes Torsional Shear stress .  The diameter of the shaft can be calculated by

τmax=16T/πd3

Design of Key

 The Dimension of the Key are set by using Standard Relation’s. Width of key Height of Key Length of Key

w=d/4 h=2/3*w l=1.5d

or

h=w

 The Key undergoes Direct Shear Stress as well as Crushing Stress and the Key needs to be checked for the Same.

Check for Shear Stress

τd=2T(d*w*l)

Check for Shear Stress

σc=4T/(d*h*l)

Design of Hub

 The Dimensions of the Hub are set using Standard Relations.

Outer Diameter “D”

Length of Hub “L” Key

D=2d

Length of Hub = Length of 

 The Hub undergoes Torsional Shear Stress and the Dimensions needs to be checked for the same.

Check for Torsional Shear Stress

τh=16T/πD3[1-k4] where

k=d/D

For Safety

τh < τall

Design of Flange

 The thickness of Flange and of Protective Flange are set by using Standard Relations.

 Thickness of Flange

 Thickness of Protective Flange

tf =0.5d tp=0.25d

 The Flange Undergoes Direct Shear Stress and Needs to be Checked for the same. Check for Direct Shear Stress

τf =2T/πD2tf 

For Safety

τf  < τall

Design of Pin

 The dimensions of the Pin are Set Using Standard relation’s. Number of Pins n

dp 1/2 d Dia0.5d/(n) of Enlarged portion 1 Outer Dia of Rubber Bush d 2 Nominal Dia of Pin

n=3 for d less than 30mm n=4 for 30 < d ≤75 n=6 for 75< d ≤110 n=8 for 80< d ≤150

dp= d1= db+4mm

d2=d1+16

D1 D1=D+d2+(2*8)

Bolt Circle Dia

Length of Bush in Flange

Pb

Pb=2T/(nD1d2lb)

 The Pin’s need to be checked for Max Shear Stress and Max Principal Stress. Max Shear Stress

τmax=[(σb/2)2+τb2]1/2

Max Principal Stress. [(σb/2)2+τb2]1/2

σmax=(σb/2)+

σb = {32*F*(lb/2)+5}/∏db3

F = T/[n*(D1/2)]

τb = F/[π * db2 /4]

For Safety

τmax < τall

Outer Diameter of Flange D 2

D2=(2D1 - D)