Page 169 - The Tribology Handbook

Roller chain drives B2

LUBRICATION METHODS

There are four basic methods for lubricating chain drives. Bath or disc lubrication
The recommended methods shown in the ratings charts
are determined by chain speed and power transmitted. Type 3
The use of better methods is acceptable and may be With oil bath lubrication the lower strand of chain runs
beneficial. through a sump of oil in the drive housing. The oil level
should cover the chain at its lowest point whilst operating.
Manual operation With slinger disc lubrication an oil bath is used but the
chain operates above the oil level. A disc picks up oil from
the sump and deposits it on the chain by means of
Type 1 deflection plates. When such discs are employed they
Oil is applied periodically with a brush or oil can, should be designed to have peripheral speeds between the
preferably once every 8 hours of operation. Volume and minimum and maximum limits of 180 to 2440 m/min.
frequency should be sufficient to just keep the chain wet
with oil and a.llow penetration of clean lubricant into the
chain joints. Applying lubricant by aerosol can be satisfac-
tory under some conditions, but it is important that the
aerosol lubricant is of an approved type for the applica-
tion. An ideal lubricant ‘winds in’ to the pin/bush/roller
clearances, resisting both the tendency to drip or drain
when the chain is stationary, and centrifugal ‘flinging’
when the chain is moving.

MEDIUM POWER
MEDIUM SPEED

LOW POWER

LOW SPEED
Oil stream lubrication
Type 4
A continuous supply of oil from a circulating pump or
central lubricating system is directed onto the chain. It is
important to ensure that the spray pipe holes, from which
the oil emerges, are in line with the chain plate edges. The
spray pipe should be positioned so that the oil is delivered
Drip lubrication onto the chain just before it engages with the driver wheel.
This ensures that the lubricant is centrifuged through the
Type 2 chain and assists in cushioning roller impact on the
Oil drips are directed between the link plate edges from a sprocket teeth, When a chain is properly lubricated a
drip lubricator. Volume and frequency should be sufficient wedge of clean lubricant is formed in the chain joints and
to allow penetration of lubricant into the chain joints. metal contact is rninimised. Oil stream lubrication also
provides effective cooling and impact damping at high
speeds. It is, therefore, important that the method of
lubrication specified in the ratings chart is closely
followed.

LOW POWER
MEDIUM SPEED

€32.5