Reliability
215
The reliability of the components are from Table D.3. The 2s for the components are stated (high extreme) (mean) (low extreme) -6 for f ailu re
rates/hr.
Bearings and Seals
From Eq. (D.2)
2 = 2aKF
Kf = 30 for rail-mounted equipment with Eq. (D.2.), Table D.2
(a) Ball bearing high speed heavy duty (high, mean, low)x .6
failure/hr
26 = (3.53, 1.8, 0.072)
(b) Rotating seals
26 = (1.12, 0.7, 0.25) = 262
For all -6 components use the high extreme 3.53 x 10 .6 for ball bearing and 1.12 x 10 .6 for rotating seals which means shorter life, cheaper
parts, and maybe a good design. For a bearing and its seals reliability
R = exp[--KF(2al + 2a2)t]
[" 139.5
= exp [- 1-6~-/r t
Gear Pairs
g F -----30
(c) Spur gears for high failure rate
2a = (4.3, 2.175, 0.087) -- 263
[- 129 -]
Rgear = exp[KFR63t]----exp|-- ,,--~C_ t
|
k lUvlll _]
Shafting
KF =30
(d) Shafting
26 = (0.62, 0.35, 0.15) = 264
18.6 -1
Rshafting = exp[KF~G4] ---= exp 1~- ~rr t|
/