Oil-Lubricated Ball Bearings
Lubrication charts or special instructions are
generally furnished for electric motors and generators
equipped with oil-lubricated ball bearings. The oil level
inside the bearing housing should be maintained about
even with the lowest point of the bearing inner ring. At
this level, there will be enough oil to lubricate the
bearing for its operating period, but not enough to cause
churning or overheating.
One common method by which the oil level is
maintained in ball bearings is the wick-fed method In
this method, the oil is fed from an oil cup to the inside
of the bearing housing through an absorbent wick. This
Figure 7-4.--Wkk-fed bell bearings.
wick also filters the oil and prevents leakage through the
are prelubricated. Cleaning will remove the lubricant
cup if momentary pressure is built up within the
from the bearings or can dilute the lubricant until it no
housing. A typical wick-fed, oil-lubricated ball bearing
longer possesses its original lubricating qualities.
is shown in figure 7-4.
Permanently lubricated ball bearings require no
Grease-Lubricated Ball Bearings
greasing. You can recognize equipment furnished with
Preferred Navy bearing greases for shipboard
these bearings by the absence of grease fittings or the
auxiliary machinery are as follows:
provision for attaching grease fittings. When
permanently lubricated bearings become imperative,
1. Bearings operating below 110°C (230°F) in
replace them with bearings of the same kind. If not
non-noise or noise-critical application should use
already provided, attach DO NOT LUBRICATE
DOD-G-24508 grease. It is available in a 1-pound can
nameplates to the bearing housing of machines with
Cleaning Bali Bearings
2. Bearings operating near water (for example,
rudder stock bearings) should use grease MIL-G-24139.
You can clean an open or a single-sealed ball
It is available in a 5-pound can under NSN
bearing only in an emergency when a suitable replace-
ment is not available. It is difficult to remove dirt from
ball bearings. Unless the cleaning is carefully done,
NOTE: Other size containers may be available
more dirt may get into the bearings than is removed
under other NSNs.
DOUBLE-SHIELDED OR DOUBLE-SEALED
In cleaning an open, single-shielded or single-
BALL BEARINGS SHOULD NEVER BE
sealed bearing, take the bearing off with a bearing puller
DISASSEMBLED OR CLEANED. These bearings
applied to the inner race of the bearing. Figure 7-5,
Figure 7-5.--Bearing pullers.