Page 83 - Mechanical Engineer's Data Handbook

72 MECHANICAL ENGINEER'S DATA HANDBOOK

Annular ring:
m =pn(ri -rf)b

2.4.3 Hooke's joint (cardan joint)

This is a type of flexible shaft coupling used extensively
for vehicle drives. They are used in pairs when there is
parallel misalignment.
Symbols used :
N = input speed
N, = output speed
a = angle of input to output shaft
I
0 =angle of rotation
Thin ring:
If rm =mean radius, A =cross-sectional area. N2
m = 2nr,Ap
k=rm
2
I = mr,

Spokes of uniform cross-section:
m= p(r, -rl)A
N cos a
Speed ratio>=
N, 1-sin2acos2a
I, = mk2 1
Maximum speed ratio = ~ (at 0 =O" or 180")
Spoked wheel: cos a
The hub and rim are regarded as annular rings. Minimum speed ratio=cosa (at 0=90" or 270")
I =l,,u,,+lrim+nl, N +1
2=1, when 0=cos-'
where: n = number of spokes. Nl JG