Specifies the influence of production and operating parameters on the connection acceptability.
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Access: |
On the Design tab, Power Transmission panel, click Key, Involute Splines, or Parallel Splines, and on the Calculation tab click Loading Conditions. |
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Joint Type |
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Fixed |
Splines are firmly joined by pressing or fixed by rings, avoiding axial movement. |
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Flexible |
Splines are flexibly joined to allow axial movement. |
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Crowned |
Uses external splines with crowned teeth for misalignment up to 5 degrees. |
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Note: This option is available for Involute Splines only and if the ANSI Standard is selected.
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Ka - Application factor
This coefficient reflects the effect of the character and the type of loading on decrease of the loading capacity or the coupling. It is determined according to empirical values given in the following table:
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Drive |
Type of loading |
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Continuous |
Light shocks |
Cyclical shocks |
Heavy shocks |
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Uniform |
1.0 |
1.2 |
1.5 |
1.8 |
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Light shocks |
1.2 |
1.3 |
1.8 |
2.1 |
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Medium shocks |
2.0 |
2.2 |
2.4 |
2.8 |
Fatigue-life factor
This coefficient reflects effects of the operational character and appropriate service life of the coupling (measured in number of torque cycles) on increase of the loading capacity of the coupling. It is determined according to empirical values given in the following table:
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No. of Torque Cycles |
Fatigue-life factor, Kf |
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Unidirectional |
Fully bi-directional |
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10000 |
1.0 |
1.0 |
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100000 |
0.5 |
0.4 |
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1000000 |
0.4 |
0.3 |
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10000000 |
0.3 |
0.2 |
Wear-life factor
This coefficient reflects effects of wear of contact surfaces during the appropriate service life of the coupling (measured in number of revolutions) on increase of the loading capacity the coupling. It is determined according to empirical values given in the following table:
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Total number of revolutions [millions] |
K w |
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0.01 |
4.0 |
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0.1 |
2.8 |
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1 |
2.0 |
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10 |
1.4 |
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100 |
1.0 |
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1000 |
0.7 |
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10000 |
0.5 |
Load Distribution factor
In couplings with two keys, the loading is not distributed exactly uniformly onto the two keys due to production and assembly inaccuracies. The actual load bearing surface of the coupling is lower than the load bearing surface determined theoretically. The ratio between the theoretical and actual load bearing surface of the coupling is defined by the coefficient of distribution of the loading. With regards to the accuracy of bearing, the size of the coefficient is given in a range from 0.6 to 0.8.
Tip: For common accuracy of production and installation, a coefficient of 0.75 is taken into account .
Factor of Tooth Side Contact
The factor indicates the load is not spread evenly on all the spline teeth because of production and assembly inaccuracy. At a common and higher mounting accuracy, it is assumed that half of the teeth carry the load (K s = 0.5). For splines with higher production inaccuracy, the load is only carried by one third of the teeth (K s = 0.3).