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 friction lining is equal to 25 mm. Assume uniform contact pressure of 1 MPa. The value of outside radius of the friction lining is:
1. 39.4 mm
2. 49.5 mm
3. 97.9 mm
4. 142.9 mm

Answer 1

Correct Answer - Option 1 : 39.4 mm

According to uniform pressure theory,

p = constant = 1 MPa

Power transmitted, \(P = T\:\omega = \frac{{T \times\; 2\;\pi N}}{{60}}\)

\(\begin{array}{l} T = \frac{{60 \times 5 \times {{10}^3}}}{{2\pi \times 2000}} = 23.87\ Nm\\ T = \frac{2}{3} \times \mu p\pi \left( {r_1^3 - r_2^3} \right)\\ \Rightarrow 23.81 \times {10^3} = \frac{2}{3} \times 0.25 \times 1 \times \left( {r_1^3 - {{25}^3}} \right) \times \pi \end{array}\)

∴ r₁ = 39.4 mm