Components $6,7$ and $9$ are rotating elements whose failure analysis criteria include

strength, life and wear. Carry out the following :

$($i$)$ By referring to the working principle of the system shown, discuss four factors

that would lead to wear and consequent failure of the highlighted components.

$[4$ Marks$]$

$($ii$)$ Two fits, H$9/$d$10$ and H$7/$p$6$ have been proposed to be used during assembly

of components $6,7,9$ and $10.$

Using the diameter obtained in question $3$ above and the Table of Limits and

Fits attached, determine the working limits for components $9$ and $10.$ Which

fit would be used in order to avoid problems of component wear and failure?

$[8$ Marks$]$

Component $2$ is to be used to 'connect'shafts from components $1$ and $3.$ Answer the

following questions:

$($i$)$ Make a neat sectioned and labelled sketch of component $2,$ showing the

internal connection with shafts from components $1$ and $3.$

$[4$ Marks$]$

$($ii$)$ For a required torque of $500$ Nm $,$ determine the dimensions of the connector

$($ie muff coupling: internal shaft diameter, $d,$ and external sleeve diameter $D),$

given that $k=\frac{d}{D}=0\mathrm{.}25$ and that ${}_c=175$MPa

Marks$]$

Hint: $T=\frac{}{16}*{}_c*D^3(1-k^4)$

$($iii$)$ Determine the dimensions of the key in each side of the connector $($ie $l,w,t.$

Hint: $l=\frac{L}{2}=\frac{3\mathrm{.}5d}{2}$;$T=l.w.{}_c*\frac{d}{2}=l*\frac{t}{2}*{}_c*\frac{d}{2}$

$[3$ Marks$]$

$($iv$)$ Explain the working principle of the multi$-$disc clutch shown in Figure $2$

below and discuss any four requirements for the materials used for lining of

the friction surfaces.