Page 442 - Rollingbearings

4 Self-aligning ball bearings
Greases for capped bearings Where the operating conditions differ, the Large self-aligning
grease life obtained from the diagram should
Bearings sealed on both sides are lubricated be adjusted: ball bearings
for the life of the bearing and are virtually
maintenance-free They are illed with one of • vertical shafts † 50% of the obtained value • are available in the 130 and 139 series
the following standard greases, which have • heavier loads (P > 0,05 C) † apply reduc- • are equipped with an annular groove in
good corrosion-inhibiting properties (table 1): tion factor (table 2) the outer ring and (ig. 7):
– three equally-spaced lubrication holes
• D ≤ 62 † MT47 grease When sealed bearings must operate under in the outer ring
• D > 62 † MT33 grease certain extreme conditions, such as very – six equally-spaced lubrication holes in
high speeds or high temperatures, grease the inner ring
may appear on the capping diameter For • can be used in any application where low
Grease life for capped bearing arrangements where this would be friction is preferred over high load carrying
bearings detrimental, appropriate actions should be capacity (e g in the paper industry)
4 taken For additional information, contact
• is presented as L , i e the time period at the SKF application engineering service
10
the end of which 90% of the bearings are
still reliably lubricated Bearings with an
• depends on the operating temperature extended inner ring
and the nd value (diagram 1)
m
The grease life speciied in diagram 1 is valid • are (ig. 8) designed for less demanding
for the following combination of operating applications that use commercial grade
conditions: shafting
• have a special bore tolerance, class JS7
• horizontal shaft (table 3), that facilitates mounting and
• inner ring rotation dismounting
• light load (P ≤ 0,05 C) • are located axially on the shaft by means
• operating temperature within the green of a slot at one end of the inner ring that
temperature zone of the grease (table 1) engages a pin or shoulder screw (ig. 9)
• stationary machine itted to the shaft
• low vibration levels This also prevents the shaft from spin-
ning in the bearing bore

Diagram 1
Grease life for standard capped self-aligning ball bearings where P = 0,05 C
Grease life L [h]
10
100 000
nd m = 100 000 nd m = 20 000
200 000
300 000
400 000
10 000
500 000
600 000
700 000

1 000
n = rotational speed [r/min]
d = bearing mean diameter [mm]
m
= 0,5 (d + D)

100
GPF = 1 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115
Operating temperature [°C]
for grease performance factor GPF = 1

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