Page 101 - Mechanical Engineer's Data Handbook

90 MECHANICAL ENGINEER’S DATA HANDBOOK

Let:
m=mass of shoe
k = spring stiffness
x = deflection of spring
p = coefficient of friction
F = radial force on drum
N = rotational speed
o = angular velocity
Torque capacity (2 shoes) T=2pr(mro2 - kx)
where: w=2nN.

f

2.8.9 Dynamometers

The power output of a rotary machine may be
measured by means of a friction brake. The forces are
measured by spring balances or load cells. Other types
of dynamometer include fluid brakes and electric
generators.
Torque absorbed T=r(F, -F2)
Power P=2nNT

2.9 Bearings

The full analysis of heavily loaded plain bearings is Important factors are, load capacity, length to
extremely complex. For so called ‘lightly-loaded bear- diameter ratio, and allowable pressure on bearing
ings’ the calculation of power loss is simple for both material.
journal and thrust bearings. Information is also given on rolling bearings.

2.9. I Lightly loaded plain bearings

Let :
P = power t = radial clearance
L = length rl =inner radius
D = diameter r2 =outer radius
p = absolute viscosity N = rotational speed