Question

A disk clutch is required to transmit 5 kW at 2000 rpm. The disk has a friction lining with coefficient of friction equal to 0.25. Bore radius of the friction lining is equal to 25 mm. Assume uniform contact pressure of 1 MPa. The value of outside radius of the friction lining is

• A. 97.9 mm
• B. 142.9 mm
• C. 49.5 mm
• D. 39.4 mm

Answer 1

The correct option is D 39.4 mm

According to uniform pressure theory,
$P=1MPa$

Power transmitted,

$P=T\omega =\frac{T\times 2\pi N}{60}$

$\Rightarrow T=\frac{60\times 5\times {10}^3}{2\pi \times 2000}=23.87Nm$

$T=\frac{2}{3}\times \mu P\pi (r_1^3-r_2^3)$
$\Rightarrow 23.81\times {10}^3=\frac{2}{3}\times 0.25\times 1\times (r_1^3-{25}^3)\times \pi$

$r_1=39.4mm$