Lubrication

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OBJECT OF LUBRICATION

The lubrication method and the lubricant have a direct effect on the bearing life; the most suitable lubrication must therefore be selected for each application. Effects of lubrication are described as follows:

(1)DECREASE OF FRICTION AND ABRASION
It decreases rolling friction between the raceway and the rolling elements, sliding friction between rolling element and cage and sliding friction of guide surface between the cage and the bearing ring.

(2) REDUCTION OF HEAT GENERATION
It dissipates heat generated inside the bearing as well as heat conducted from the outside thus preventing overheating of the bearing and deterioration of the lubricant.

(3) PROTECTION FROM CORROSION AND CONTAMINANTS
It prevents corrosion of rolling elements, bearing rings and cages and also prevents the ingress of contaminants and moisture into the bearing.


REQUIRED CHARACTERISTICS OF THE LUBRICANT

(1)LOW FRICTION AND ABRASION
(2) HIGH STABILITY AGAINST HEAT, GOOD THERMAL CONDUCTIVITY
(3) STRONG OIL FILM
(4) NON-CORROSIVE
(5) PROVIDE A GOOD BARRIER AGAINST DUST AND MOISTURE
(6) MAINTAIN A STABLE VISCOSITY

 

LUBRICATION METHOD

There are two types of lubricant: oil or grease. It is important to select the correct lubricant and lubrication method for each application and its conditions.

LUBRICATING OIL AND GREASE

. LUBRICATING OIL LUBRICATING GREASE
ROTATING SPEED LOWMEDIUMHIGH SPEED LOWMEDIUM SPEED
LUBRICANT EFFICIENCY EXCELLENT GOOD
COOLING EFFECT GOOD NONE
TORQUE COMPARATIVELY LOW COMPARATIVELY HIGH
LUBRICANT LIFE LONG COMPARATIVELY SHORT
LUBRICANT REPLACEMENT EASY DIFFICULT
LUBRICANT LEAKAGE SHOULD NOT BE USED WHERE OIL LEAKAGE IS UNACCEPTABLE LITTLE GREASE LEAKAGE
IMPURITIES FILTRATION EASY DIFFICULT
SEALING EQUIPMENT COMPLEX SIMPLE


GREASE FILLING VOLUME
SYMBOL FILLING VOLUME(%) OPERATING CONDITION
SPEED LOAD
M 7010 LOW HEAVY
S 5010 LOW MEDIUM
G 4010 MEDIUM MEDIUM
L 3010 MEDIUM MEDIUM
Q 255 MEDIUM MEDIUM
K 205 HIGH LIGHT
X 105 HIGH LIGHT
NOTE: LIGHT LOAD ( 0.06Cr)
STANDARD LOAD ( 0.12Cr)

CRITERIA FOR LUBRICATING OIL SELECTION
OPERATING TEMPERATURE OF BEARING() dn ISO VISCOSITY GRADE OF
LUBRICATING OIL(VG)
MEDIUM LOAD HEAVY LOAD/
SHOCK LOAD
-300 UP TO PERMISSIBLE ROTATING SPEED 15,22,32 32,46
0+60 UP TO 15000 32,46,68 100
1500080000 32,46 68
80000150000 22,32 32
150000500000 10 22,32
+60+100 UP TO 15000 150 220
1500080000 100 150
80000150000 68 100,150
150000500000 32 68
+100+150 UP TO PERMISSIBLE ROTATING SPEED 320
NOTE: 1.IF HEAVY LOADS OCCUR AT LOW SPEEDS, A HIGHER VISCOSITY LUBRICATING OIL SHOULD BE USED.
2.THIS TABLE IS FOR OIL BATH LUBRICATION SYSTEM AND RECIRCULATING OIL SYSTEMS.
3.dn = BEARING BORE DIAMETER d(mm) ROTATING SPEED n(r.p.m)