Page 107 - Rollingbearings

Size selection based on static load
Equivalent static where Fig. 4
bearing load P = equivalent static bearing load [kN] Equivalent static bearing load
0
F = actual radial bearing load [kN]
r
F = actual axial bearing load [kN]
a
Loads comprising radial and axial compo- X = radial load factor for the bearing
0
nents that are to be evaluated in relation to Y = axial load factor for the bearing
0
the static load rating C , must be converted
0
into an equivalent static bearing load. This is Information and data required for calculating
deined as that hypothetical load (radial for a the equivalent static bearing load P is pro-
0
radial bearing and axial for a thrust bearing) vided in the relevant product sections. F a
which, when applied, would cause the same In the equation, use radial and axial com-
maximum rolling element load in the bear- ponent values (ig. 4) for the maximum load F r P 0
ing as the actual loads to which the bearing that can occur. If the load varies then con-
is subjected. It is obtained from the general sider the combination that induces the high-
equation est value of P .
0
P = X F + Y F
0 a
0 r

Table 6
for different level of contamination
Guideline values for factor η c
Conditions Factor η c 1)
for bearings with diameter
d < 100 d ≥ 100 mm
m
m
Extreme cleanliness 1 1
• Particle size of the order of the lubricant ilm thickness
• Laboratory conditions
High cleanliness 0,8 ... 0,6 0,9 ... 0,8
• Oil iltered through an extremely ine ilter
• Typical conditions: sealed bearings that are greased for life

Normal cleanliness 0,6 ... 0,5 0,8 ... 0,6
• Oil iltered through a ine ilter Bearing size
• Typical conditions: shielded bearings that are greased for life
Slight contamination 0,5 ... 0,3 0,6 ... 0,4
• Typical conditions: bearings without integral seals, coarse iltering,
wear particles and slight ingress of contaminants B.3
Typical contamination 0,3 ... 0,1 0,4 ... 0,2
• Typical conditions: bearings without integral seals, coarse iltering,
wear particles, and ingress from surroundings

Severe contamination 0,1 ... 0 0,1 ... 0
• Typical conditions: high levels of contamination due to excessive wear
and/or ineffective seals
• Bearing arrangement with ineffective or damaged seals
Very severe contamination 0 0
• Typical conditions: contamination levels so severe that values of ηc are
outside the scale, which signiicantly reduces the bearing life

1) The scale for η c refers only to typical solid contaminants. Contamination by water or other luids detrimental to bearing life is not included. Because of strong abrasive wear in highly contaminated environ-
ments (η c = 0), the useful life of the bearing can be signiicantly shorter than the rating life.

105