Hisun HS400 - Page 40

General
1-34
Interference fit
1. Follow this procedure when
installing a bearing over a shaft.
When a tight fit is required, the
bearing inside diameter is smaller
than the shaft. In this case. Driving
the bearing on the shaft using
normal methods may cause bearing
damage. Instead, heat the bearing
before installation. Note the
following:
• Secure the shaft so it is ready for
bearing installation.
• Clean all residues from the bearing
surface of the shaft. Remove burrs
with a file or sandpaper.
• Fill a suitable pot or beaker with
clean mineral oil. Place a
thermometer rated above
120℃(248°F) in the oil. Support the
thermometer so it does not rest on
the bottom or side of the pot.
• Remove the bearing from its
wrapper and secure it with a piece
of heavy wire bent to hold it in the
pot. Hang the bearing in the pot so
it does not touch the bottom or
sides of the pot.
• Turn the heat on and monitor the
thermometer. When the oil
temperature rises to approximately
120℃(248°F), remove the bearing
from the pot and quickly install it. If
necessary, place a socket on the
inner bearing race and tap the
bearing into place.
•
As the bearing chills, it will
tighten on the shaft, so install
it quickly. Make sure the
bearing is installed
completely.
2. Follow this step when installing a
bearing in a housing. Bearings are
general installed in a housing with a
slight interference fit Driving the
bearing into the housing using
normal methods may damage the
housing or cause bearing damage.
Instead, heat the housing before the
bearing is installed.
Caution;
Before heating the housing in this
procedure, wash the housing
thoroughly with detergent and water.
Rinse and rewash the cases as required
to remove all traces of oil and other
chemical deposits.
• Heat the housing to approximately
100℃ (212°F) in an oven or on a
hot plate. An easy way to check that
it is the proper temperature is to
place tiny drops of water on the
housing; if they sizzle and
evaporate immediately, the
temperature is correct. Heat only
one housing at a time.
Caution:
Do not heat the housing with a propane
or acetylene torch. Never bring a flame
into contact with the bearing or
housing. The direct heat will destroy
the case hardening of the bearing and
will likely warp the housing.
• Remove the housing from the oven
or hot plate, and hold onto the
housing with welding gloves. It is
hot!