$4$

A cast iron flange coupling needs to be designed for a steel shaft transmitting $15$ kW at $200$ rpm and having

$10$

an allowable shear stress of $40$ MPa $.$ The working stress in the bolts gre not to exceed $30$ MPa $.$ The maximum torque is $25\%$ greater than the full load torque The allowable shear stress for cast iron is $14$ MPa $.$ Assume that the same material is used for shaft and key and that the crushing stress is twice the value of its shear gotress Refer figure $4.$

Empirical relations$/$Usual proportions:

Oysilide diameter of hub.

$D=2d$

Kength of hub,

$L=1\mathrm{.}5d$

Pifch circle diameter of bolts,

$D_1=3d$

Qitside diameter of flange,

$D_2=D_1+(D_1-D)=2D_1-D=4d$

$t_f=0\mathrm{.}5d$

$=3,$ for dupto $40mm$

$=4,$ for $d$ upto $100mm$

$=6,$ for dupto $180mm$

Thickness of flange,

Number of bolts

Other dimensions are shown in Figure $4$