Page 47 - Mechanical Engineer's Data Handbook

36 MECHANICAL ENGINEER’S DATA HANDBOOK
y =deflection
E =Young’s modulus
v = Poisson’s ratio
P nGD4 k,, k,, k,=constants
Stiffness s = - = -
y 32RZL urn =maximum stress
W= load
nD3r
Maximum load P,, = -
16R
W= [ (h - e -$) + t3] (may be negative)
y
t
(1 -vz)klD:
I .SA Belleville washer spring (disk or
diaphragm spring) arn=(l-v2)klD~ [,,(h-i),,,t]
This is an annular dished steel ring which deflects (positive for A, negative for B. Stress is positive or
axially under load. Several springs may be used in negative depending on the value of y)
series or parallel arrangements to give lower or higher
stiffness, respectively. The spring is space saving and
its non-linear characteristics can be altered consider- DoPi kl k, k3
ably by varying the proportions.
1.4 0.46 1.07 1.14
Symbols used: 1.8 0.64 1.18 1.30
Do = outer diameter 2.2 0.73 1.27 1.46
Di =inner diameter 2.6 0.76 1.35 1.60
t = thickness 3 .O 0.78 1.43 1.74
h = height 3.4 0.80 1 .so 1.88
3.8 0.80 1.57 2 .oo
4.2 0.80 1.64 2.14
4.6 0.80 1.71 2.26
5.0 0.79 1.77 2.38
c

_- --
I Series stacking

WI

Parallel stacking