Page 248 - Rollingbearings

1 Deep groove ball bearings
Grease life for capped bearings Table 4
1 Where the operating conditions differ as
• is presented as L , i.e. the time period at described below, the grease life obtained Reduction factor for the grease life,
10
the end of which 90% of the bearings are from the diagram should be adjusted: depending on the load
still reliably lubricated (diagram 1)
• depends on: • for vertical shafts, use 50% of the obtained Load P Reduction factor
– the operating temperature value
– the speed factor, nd m • for heavier loads (P > 0,05 C), apply a ≤ 0,05 C 1 0,7
0,1 C
– grease performance factor (GPF) reduction factor (table 4)
(table 3, page 245) 0,125 C 0,5
0,25 C 0,2
When capped bearings must operate under
The indicated grease life is valid under this certain extreme conditions, such as very
combination of operating conditions: high speeds or high temperatures, grease
may appear on the capping diameter. For
• horizontal shaft bearing arrangements where this would be
• inner ring rotation detrimental, appropriate actions could be
• light load (P ≤ 0,05 C) taken. For additional information, contact
• operating temperature within the green the SKF application engineering service.
temperature zone of the grease (table 3)
• stationary machine
• low vibration levels

Diagram 1
Grease life for capped deep groove ball bearings where P = 0,05 C

Grease life L 10 [h]
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

100
GPF = 1 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115
GPF = 2 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130
GPF = 4 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145
Operating temperature [°C]
for various grease performance factors (GPF)
n = rotational speed [r/min]
d m = bearing mean diameter [mm]
= 0,5 (d + D)

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