The frictional torque transmitted in a flat pivot bearing assuming uniform wear
Frictional troque transmitted
μ = Coefficient of friction
W = Load over the bearing
R = Radius of bearing
A single clutch operating under dry sliding condition transmits 150 Nm. The average coefficient of friction is 0.3 and maximum operating pressure is 0.5 MPa. The ratio between the outside radius and inner radius is 1.73. Under uniform wear conditions, if the outside radius of the clutch is to be minimum, the inside radius will have to be
Torque transmitted = 150 N-m
For uniform wear
p • r = Constant
0.5 x r1 = C
Torque transmitted =
Consider the following statements regarding a centrifugal clutch:
1. It need not be unloaded before engagement.
2. It enables the prime mover to start up under no-load conditions.
3. It picks up the load gradually with the increase in speed.
4. It will not slip to the point of destruction.
5. It is very useful when the power unit has a low starting torque.
Q. Which of these are the advantages of a centrifugal clutch?
Centrifugal clutch will have slip as it is example of friction clutch. it has to be unloaded before engagement.
Fc = mω2r
A clutch has outer and inner diameters 100 mm and 40 mm respectively. Assuming a uniform pressure of 2 MPa and coefficient of friction of liner material 0.4, the torque carrying capacity of the clutch is
Using uniform pressure theory, torque carrying capacity of clutch is given by
= 195936 Nmm
= 195.936 Nm.
A disc clutch is required to transmit 5 kW at 2000 rpm. The disc has a friction lining with coefficient of friction equal to 0.25. Bore radius of friction lining is equal 0.25 mm. Assume uniform contact pressure of 1 MPa. The value of outside radius of the friction lining is
Power Transmitted = 5 kW
N = 2000 rpm
μ = 0.25
r1 = 25 mm
Uniform Pressure = 1 MPa
T = 23.87 N-m
ro= 39.4 mm
Bolts in a rigid flangecoupling fails in shear and crushing.
Which one of the following statement is correct? In case of clutches, the uniform pressure theory:
Which one of the following is the correct expression for the torque transmitted by a conical clutch of outer radius R, inner radius r and semi-cone angle a assuming uniform pressure? (where W = total axial load and μ = coefficient of friction)
Conical clutch, uniform pressure
where, α → semi angle of cone for uniform wear
In a plate clutch axial force is 4 kN. The inside radius of contact surface is 50 mm and the outside radius is 100 mm. For uniform pressure the mean radius of friction surface will be
In the multiple disc clutch, if there are 6 discs on the driving shaft and 5 discs on the driven shaft, then the number of pairs of contact surfaces will be equal to
n = n1 + n2 -1 = 6 + 5 - 1 = 10
In cone clutch