Initial grease fill
Open angular contact thrust ball bearings for screw drives should be lubricated with a grease quantity that fills ~ 25 to 35% of the free space in the bearing.
Freshly greased bearings should be operated at low speeds during the running-in period (→ Running-in of grease lubricated bearings.) This enables excess grease to be displaced and the remainder to be evenly distributed within the bearing. If this running-in phase is neglected, there is a risk that temperature peaks can lead to premature bearing failure.
The initial grease fill depends on the bearing type, series and size as well as the speed factor A.
A = n dm
where
| A
| = | speed factor [mm/min]
|
| dm | = | bearing mean diameter [mm]
= 0,5 (d + D) |
| n | = | rotational speed [r/min] |
The initial grease fill for open bearings can be estimated using
G = K Gref
where
| G
| = | initial grease fill [cm3]
|
| Gref | = | reference grease quantity [cm3] (→ Product tables) |
| K | = | a calculation factor dependent on the bearing type and the speed factor A (diagram 1)
|
- high-speed capability
- excellent resistance to ageing
- very good rust inhibiting properties
The technical specifications of the grease are listed in table 1.
