REXNORD - MARBETT - MCC
B79
d
dm
4
6
8
10
13
15
18
20
1,0
0,7
0,5
0,2
0,1
Grease life in bearings lubricated for life
Data:
- Bearing Type
A
.
- d = 40 mm (shaft dia.).
- dm = 60 mm. (bearing mean dia.).
- n = 300 rpm. (rotational speed).
- 55 ºC (grease operating temperature).
- C = 23600 N (Dynamic load coefIcient).
- P = 3000 N (equivalent dynamic load).
- From Diagram 1, as a function of:
n x dm = 300 rpm x 60 mm = 18000
we read a nominal grease life of:
²
10h
= 100000 hours.
- From Diagram 2, as a function of:
C/P = 23600 N: 3000 N = 7,8
we read a corrective factor of:
Fc = 0,5.
- Calculation of estimated grease life:
²
h
= ²
10h
x Fc = 100000 hours x 0,5 = 50000 hours.
Example of calculation
Diagram 2 - Correction factor Fc
The corrective factor Fc, keeps into cosideration the inLuence of
load applied on bearings as a function of load ratio C/P.
With low loads (C/P ≥ 15) the duration of the grease is not
inLuenced by load values.
(dry use recommended)
C
= Dynamic load coefIcient (N).
Values are indicated in the bearings dimensional tables.
P
= Equivalent dynamic load (N).
See Table 2.
Load C/P
Correction factor Fc