Timken Super Precision Bearings for Machine Tool Applications

A
ENGINEERING
Load Factor (C l )
The C l factor is obtained from the following figure. Note that the
factor is different based on the type of bearing utilized. P r is the
equivalent load applied to the bearing in Newtons and is determined
in the Equivalent Bearing Loads (P r) section.
Speed Factor (C s )
C s is determined from the following figure, where rev/min (RPM)
is the rotational speed of the inner ring relative to the outer ring.
1000
Ball Bearings
Tapered Roller Bearings
1.0
0.9
0.8
Ball Bearings
Tapered Roller Bearings
100
0.7
Cs
0.6
Cl
0.5
10
0.4
0.3
0.2
0.1
0.0
1 10 100 1000 10000 100000 1000000 10000000
Pr (Newtons)
Fig. 48. Load factor (C l) vs. equivalent bearing load (P r).
Load Zone Factor (C j )
As mentioned previously, for all non-tapered roller bearings the
load zone factor is one (1). For tapered roller bearings, the load
zone factor can be taken from the graph based on the axial load
applied to that bearing.
1
1 10 100 1000 10000
Rotational Speed (RPM)
Fig. 50. Speed factor (C s) vs. rotational speed.
Viscosity Factor (C v )
The lubricant kinematic viscosity (centistokes [cSt]) is taken at the
operating temperature of the bearing. The operating viscosity can
be estimated by Figure 51. The viscosity factor (C v) can then be
determined from Figure 52 below.
10000
Cj
1
0.9
0.8
0.7
0.6
0.747
Kinematic Viscosity (cSt)
1000
100
10
1
ISO VG
680
460
320
220
150
100
68
46
32
0.5
0 0.5 1 1.5 2 2.5
F r
F a K
Fig. 49. Load factor (C j) vs. tapered bearing axial load (F a).
0 50 100 150 200
Temperature (˚C)
Fig. 51. Temperature vs. kinematic viscosity.
1000
Ball Bearings
Tapered Roller Bearings
100
Cv
10
1
1 10 100 1000 10000
Kinematic Viscosity (cSt)
Fig. 52. Viscosity factor (C v) vs. kinematic viscosity.
50 TIMKEN MACHINE TOOL CATALOG