Page 179 - domce

9 EXTERNAL SELF ALIGNING BALL BEARING UNITS

Installation of covered bearing units
Covered bearing units can be installed in the same way as
standard bearing units with regard to selecting and fitting the
shaft. The cover can be easily removed without the need for
special tools or jigs. The installation procedure is as follows:
Shaft Sleeve
1. Remove the steel plate cover from the bearing unit.
This can be done by hand but, if necessary, use a
screwdriver as shown.

Be sure to install the sleeve so that the nut is positioned
opposite the pulley. This will make is easier to handle the unit.
2. Fit the bearing unit over the sleeve and fit a cylindrical
support to the side face of the bearing’s inner ring (on the nut
side). Be sure it covers the whole circumference of the
bearing’s inner ring.

2. To enhance dust and moisture resistance, completely fill
the area between the two lips of the rubber seal in the
cover with grease. Also put grease into the cover inside
space, filling it to about two thirds of its volume.
3. Chamfer the shaft end to protect the lips of the rubber
seal against possible damage. By following previous
procedures, fit the inner ring to the shaft and tighten the
Washer mounting bolts to the frame. Then fit the grease cover onto
Nut Sleeve the shaft.
4. Fit the cover into the spigot of the bearing housing.
(Never hit the cover directly with a steel hammer. Always
place a large wooden or synthetic resin dowell between the
0
hammer and the cover.) Then, from a 45 angle, tap it with a
hammer around the circumference of the cover to fit it into
the groove on the bearing housing (as shown below).

3a) Gently tap the larger diameter side of the sleeve in the
direction of the arrow around the whole circumference of the
sleeve so that the bearing inner ring is closely seated on the
tapered side of the sleeve.
3b) Position the lockwasher, and fully hand-tighten the nut.

4. Fit a jig or screwdriver on the bevel of the nut, and tap it with
0
0
a hammer until the nut turns 60 to 90 . (NEVER tap the
flinger). Do not overtighten the nut as this will decrease
bearing clearance and deform the inner ring – resulting in the
5. Put grease in the other cover as for Step 2, and fit the
bearing overheating or seizing. After tightening the nut, check
cover over the shaft. If the cover is a closed type, put
that the shaft can be smoothly turned by hand.
some grease into the spigot section (see diagram top left
5. To lock the nut, bend a tab on the lockwasher into one next page). Fit the cover into the spigot of the housing as
of the bevels on the nut to stop it loosening. (NEVER slacken shown in Step 4.
the nut to suit.)
6. Securely install the bearing housing to the frame.

175