Page 75 - The Tribology Handbook

A12 Plain bearing form and installation

S ELECT1 0 N

Types of replaceable plain bearing
Bush Half bearing

SOLID SPLIT CLENCHED THINWALL MEDIUM WALL THICK WALL
Normal housing Solid Solid Solid Split Split Split
Location feature None None None Nick Nick or button Dowel or button
stop stop
Bearing material Monometal* Bimetal Bimetal Bimetal or Monometal, Bimetal or
trimetal bimetal or trimetal
trimetal

Manufacture Cast or machine Wrap from flat Wrap from flat Press from flat Cast lining on Cast lining on
from solid strip strip strip preformed preformed
blanks blanks
Forming of outside Machined As pressed Ground As pressed Fine-turned or Fine turned
diameter ground

Other points to note Mainly below Cheaper than Higher Cheapest for Moderate Made in pairs
when selecting a 50 mm dia. solid in precision mass pro- quantities for 1-10 off
suitable type quantity duction 10-100 off
* Rarely large solid bimetal bushes are made for end assembly Double-flanged half bearings (thin and thick wall) and single
in solid housings. The wall thickness would approximate to flanged (solid) bushes are also used.
that of medium-wall half bearings. An oil distribution groove may be cut circumferentially in the
Double split bushes, with halves directly bolted together have outside diameter of thick-wall bearings only.
been used in the past for turbine bearings, and some gearbox
and ring oiled bearings. These are not now common in
modern designs.

Choice of wall thickness
In the past, the shaft was chosen as the basis. The
emphasis is now changing to standardising on the housing
size.
LERANCE
BEARING
BORE
MINIMUM CLEARANCE
MINIMUM CLEARANCE
ALLOWANCE A
T- TOLERANCET
TOLERANCE I I ON SHAFT
ON SHAFT
BASIC
SIZE n

.1 I
/
PREFERRED
FACILITATES INTERCHANGEABILITY AND PRIMARY USE WHEN PREGROUND BAR
STANDAROISATION OF BEARINGS STOCK CAN BE USED FOR JOURNAL
A12.1