Tuesday, September 6, 2016

Bearing Design Guide: Chapter Six: Recommended Assembly and Retention Practices

         There are many methods used to assemble to retain sleeve bearings in an assembly to prevent movement under rotation and load in service. Some of these methods include bolting the bearing with a retainer, a lugged end plate, set screwing, knurled or coarse threading the sleeve OD, key retention or retained by cap screw, press fitting and shrink fitting.

         Although the latter two methods are the most popular and give the most positive, efficient, economical and simplest means with little or no specialized equipment being necessary, each method will be described briefly.

FIGURE 1: BOLTED:                                                              
The sleeve bearing is slip-fitted into the housing
against the shoulder in the housing bore. The
bolted plate is counter bored to permit the
bearing to be in contact with it; the bearing
length tolerance should not be greater than .005"
and ends must be parallel and square.

Bearing pressed or slide fit into housing and
retained by lugged end plate. Slot is milled in
end of bearing to a depth of slightly below
bottom surface of the lug.

Headless setscrew tightened against flat on
bearing. Be careful not to deform bearing. The
flat on the bearing is not necessary but the setscrew
will form a burr on the bearing surface
and make removal difficult. The setscrew may
be locked in by another screw or by locking
compound. Bearing can be press or slip fitted.

Knurled or coarse-threaded outer surface used
where a die casting is to be made around the
bearing. Located one end surface of the bearing
flush with surface of housing.

Bearing dimensioned for key retention. Key seat
depth 112 wall thickness or less on small and
medium bearings. Length is specified same as key
length but milling-cutter overrun is shown. Finish machine
inner surface after key is in place.