Page 337 - The Tribology Handbook

Rolling bearing lubrication C8

Application of oil to rolling bearings

System Conditions Oil levelsloil flow rates Comments
Bath/splash Generally used where speeds are low Bearings on horizontal and vertical
shafts, immerse half lowest rolling
A limit in dn value of ooo is some- element
times quoted, but higher values can
be accommodated if churning is not Multi-row bearings on vertical shafts,
a problem fully immerse bottom row of
elements
Oil flingers, drip feed Normally as for bath/splash Flow rate dictated by particular Allows use of lower oil
lubricators, etc. application; ensure flow is sufficient level if temperature-
to allow operation of bearing below rise is too high with
desired or recommended maximum bath/splash
temperature - generally between
70°C and 90°C

Pressure circulating No real limit to dn value As a guide, use:* 0.6 cm3/min cmz of The oil flow rate has
projected area of bearing generally to be de-
Use oil mist where speeds are very high
(0.d. x width) cided by considera-
tion of the operating
temperature
Oil mist No real limit to dn value As a guide, use:* 0.1 to 0.3 x bearing In some cases oil-mist
bore (cm/2.54) x no. of rows-cm3/ lubrication may be
Almost invariably used for small bore hour combined with an
bearings above 50 000 revlmin, but oil bath, the latter
also used at lower speeds Larger amounts are required for pre- acting as a reserve
loaded units, up to 0.6 x bearing
bore (cm/2.54) x no. of rows-cm3/ supply which is par-
ticularly valuable
hour
when high-speed
bearings start to run
* It must be emphasised that values obtained will be very approximate and that the manufacturer's advice should be sought on the
performancc of equipment of a particular type.

C8.5