Page 82 - The Tribology Handbook

Oscillatory journal bearings AI 3

Spherical bearings are commonly used where the oscillatory motion is a result ofa misalignment, which may be intentional
or not. A lateral oscillatory motion is then often combined with a rotatary motion about the bearing axis. If the frequency
of rotation is high, it may require a separate bearing fitted inside the spherical assembly.

Clearance
Clearance definitions :-
Bore Radial cbarance C,

D C2 .Nod c3
From Up to Min. Max. Min. Max. Min. Max.
r

- 12 8 32 32 68 68 104
~~~~~
12 20 10 40 40 82 82 124 Usually :
4Cr<C,tBC,
20 35 12 50 50 100 100 150
35 60 15 60 60 120 120 180
~~ ~~ ~ ~ ~~ C2 CLEARANCE may somtimes be chosen
69 90 18 72 72 142 142 212
if the loading is alternating
90 140 18 85 85 165 165 245
140 240 18 100 100 192 192 284
C3 CLEARANCE is sometimes required if
240 300 18 110 110 214 214 318 the temperature difference between
inner sphere and outer ring is large, or
the bearing works in dirty conditions

Fit

Most commonjt Housing PuriiJfit Pushjt
Contact point made of in on
c2 Normal C3 lightalloy housing journal
Recommended h6 m6 m6 - 7716 h6
journal jt Journal
should be
hardened

Recommended J7 X7 M7 Jv7" H7 M7
hom'ngfi or M7

* In general, if the housing is made of light-metal alloy or other soft material, or the
housing is thin-walled, a tighter fit is required. Recommended: one degree tighter fit
than otherwise would have been chosen, i.e. Mis replaced by N, j by K, etc.
Journal Housing

A13.2