Page 72 - The Tribology Handbook

Crankshaft bearings AI 1

Locating devices
Recommended

Nick, tang or lug locates shell in axial direction only.
Lugs should be on one joint face of each shell with both
lugs positioned at the same housing joint face.
Back face of nick must not foul slot or notch in housing,
and nick should not be in heavily loaded area of bearing.
Bearing must be arranged with joint face in line with
housing joint face.

Button stops-useful for large and heavy bearing shells
-to retain upper halves in housings against falling out
by own weight. Button may be any shape but is usually
circular, and must be securely screwed to housing with
small clearance all round and at upper face.

Dowel, tight fitting in one joint face, clearance in the
other, locates shells to each other. More susceptible to
damage during assembly, does not locate shells in housing
and cannot be used on thin shells.

Not recommended

Dowel in crown-weakens shell, may induce fatigue or,
if hole pierces shell, may cause erosion and oil film break-
down. Will not prevent a seized bearing from rotating, and
when this happens damage is aggravated.
Redundant locating devices result in ‘fighting’ between
them and possible damage to bearings.
The correct conditions of installation are particularly
important with dynamically loaded bearings.

AI 1.6