Parallel Spline Calculation Formulas in English Units
Transferred torque
where:
P | transferred power [lb ft] | |
n | speed [min -1 ] |
Pressure on groove supporting surface
1. shaft inside diameter d h > 0
a) 
b) if d min ≤d h -> d min = 1.1 d h [mm]
c) if d min ≤ 1.5 d h -> d min = 1.5 d h [mm]
2. shaft inside diameter d h = 0
where:
d min | minimal shaft diameter [in] | |
d h | shaft inside diameter [inm] | |
T | torque [lbft] | |
K a | application factor | |
K f | fatigue-life factor | |
S v | desired safety | |
τ Al | Allowable Shear Stress |
Minimum splines length to transfer the torque
1. Fixed connection: |  |
2. Flexible connection: |  |
where: |
Allowable pressure
1. Fixed connection: |  |
2. Flexible connection: |  |
where: |
Strength Check
p min ≤ p ds
p min ≤ p dh
where:
p min | minimal calculated h/2 pressure [psi] | |
p ds | allowable pressure in shaft [psi] | |
p dh | allowable pressure in hub [psi] |