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9 EXTERNAL SELF ALIGNING BALL BEARING UNITS

HANDLING BEARING UNITS Cartridge type bearing units:
For normal operating conditions, the cartridge type bearing
Although bearing units are relatively robust, inappropriate
housing fit must be H7. The housing bore must be finished so
handling can lead to premature failure. Damage to bearing
the bearing unit can move freely in the axial direction.
units is often caused by improper installation or handling.
Take-up type bearing units:
INSTALLATION OF BEARING UNIT To install take-up type bearing units, fit the unit in the guide rail
on a frame, and secure the inner ring of the bearing to the
Pillow block, flange and take-up type bearing units:
shaft. Then install the adjusting bolt and nut, and lock the
Pillow block, flange and take-up type bearing units can be bearing unit with a tapered pin. Finally, correctly position the
easily installed using a wide range of mounting methods, all of bearing unit.
which allow full design performance to be achieved. Observing
the following precautions will ensure they work efficiently for
their full design life.
Installation of cylindrical bore type units
1. Ensure the mounting face is rigid, and as flat and smooth as
possible. Set screw bearing units:
2. When placing the bearing on the mounting frame, the To install the bearing unit to the shaft, equally tighten two set
bearing housing must be stably seated, without any screws to the recommended torque.
excess play. (Installing a bearing housing on an uneven
frame will deform the bearing housing, and the bearing itself,
causing the bearing to fail prematurely.)

Ball

Ball point set screws (such as those shown above) are hard to
loosen, even when subjected to vibration or impact loads. If the
Housing must be stably seated without any excess play. fitting clearance between the inner ring and the shaft is small,
3. To allow for convenient grease injection, the tolerance of the make a flat (as shown in the right hand diagram) approximately
angle between the bearing housing mounting face and the 0.2mm to 0.5mm deep on an area of the shaft to which the ball
0
shaft should be ± 2 max. For narrower outer ring bearings point of the set screw is seated. This will allow for the tight fit
0
and for covered units, the tolerance should be ± 1 max. bearing to be easily removed from the shaft.
Recommended tightening torque for set screws
S E T S C R E W
S E T S C R E W I T G H T E N I N G
B E A N I R G N . o T O R Q U E
M c i r t e N m ( m a ) x
U C 2 0 1 o t U C 2 0 5 – M 5 x 8 . 0 0 9 . 3 - 0 . 3
U C 2 0 6 U C 3 0 5 o t U C 3 0 6 M 6 x 7 . 0 5 9 . 4 - 9 . 3
±2 0
U C 2 0 7 – M 6 x 7 . 0 5 8 . 5 - 9 . 4
U C 2 0 8 o t U C 2 0 1 – M 8 x 0 . 1 0 8 . 7 - 8 . 6
U C 2 1 1 U C 3 0 7 M 8 x 0 . 1 0 8 . 9 - 9 . 8
U C 2 2 1 –
90 ±2 0 M 0 1 x 2 . 1 5 6 . 6 1 - 8 . 4 1
0
U C 2 3 1 o t U C 2 5 1 U C 3 0 8 o t U C 3 0 9 M 0 1 x 2 . 1 5 6 . 9 1 - 8 . 7 1
U C 2 6 1 - M 0 1 x 2 . 1 5 2 2 - 8 . 0 5 . 2
U C 2 7 1 o t U C 2 8 1 U C 3 0 1 o t U C 3 4 1 M 2 1 x 5 . 1 0
2 2 - 8 . 6 4 . 9
– U C 3 5 1 o t U C 3 6 1 M 4 1 x 5 . 1 0 3 3 - 7 . 1 3 . 4
– U C 3 7 1 o t U C 3 9 1 M 6 1 x 5 . 1 0 4 5 - 6 . 9 9 . 3
– U C 3 2 0 M 8 1 x 5 . 1 0 5 5 - 5 . 3 8 . 8

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