DINTECHNICAL INFORMATION

Admissible loads

All the definitions, formulas and coefficients used in this chapter are taken from the ISO 281 standard, describing the calculation of the dynamic load, and ISO 76 for the static load. The load unit is the Newton (N).

The basic dynamic radial loads C_r and the basic static loads C_or are indicated in the bearing tables. 

F_r

radial component of the applied load

F_a

axial component of the applied load

X

dynamic radial load factor

Y

dynamic axial load factor

e

limit of the F_a/F_r ratio for choosing the X and Y factors.

Single and double row ball bearings:

Equivalent dynamic radial load P_r

P_{r =} X F_r + Y F_a

The value of the X and Y coefficients depends on the F_a/C_or ratio. For an assembly with normal fit (j5 or k5 for the shaft, J6 for the housing), the following table indicates the values for the Normal radial clearances CN and C3.

Equivalent static radial load  P_or

If F_a/F_r  ≤ 0.8 then P_or = F_r

If F_a/F_r  > 0.8 then P_or = 0.6 F_r + 0.5 F_a

e-factor for single and double row ball bearings:

e

X

Y

X

Y

X

Y

X

Y

0.025

0.22

1

0

0.56

2

0.31

1

0

0.46

1.75

0.04

0.24

1

0

0.56

1.8

0.33

1

0

0.46

1.62

0.07

0.27

1

0

0.56

1.6

0.36

1

0

0.46

1.46

0.13

0.31

1

0

0.56

1.4

0.41

1

0

0.46

1.3

0.25

0.37

1

0

0.56

1.2

0.46

1

0

0.46

1.14

0.5

0.44

1

0

0.56

1

0.54

1

0

0.46

1

Self-aligning ball bearings:

Equivalent dynamic radial load P_r

If F_a/F_r  ≤ e then P_r = F_r  + Y₂ F_a

If F_a/F_r  > e then P_r = 0.65 F_r  + Y₁ F_a

Equivalent static radial load  P_or

  P_{or =}  F_r + Y₀ F_a

e-factor for self-aligning ball bearings:

Basis

e

Y₂

Y₁

Y₀

135-126-129-129/10

0.34

1.8

2.8

1.9

108-127

0.33

1.9

3

2

1200

0.32

2

3

2

2200

0.66

1

1.5

1

1301

0.35

1.8

2.8

1.9

Double row angular contact ball bearing:

Equivalent dynamic radial load P_r

If F_a/F_r  ≤ 0.68 then P_r = F_r  + 0.92 F_a

If F_a/F_r  > 0.68 then P_r =  0.67 F_r  + 1.41 F_a

Equivalent static radial load  P_or

P_{or =}  F_r + 0.76 F_a

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