Machine Design and Engineering

Sleeve Shaft Coupling Design Equations and Calculator.

Torque Capacity of Shaft T = π D³ τ / 16

Torque Capacity of Key T = ( D b L τ ) / 2

Power Capacity of Shaft P = π² N D³ b τ / 8

Torque capacity of sleeve T = π τ ( D_o⁴ - D⁴ ) / ( 16 D_o)
An allowance should be made for keyway)

For equal strength of sleeve and shaft D_o = 1.22 D

Where:

Symbols used:
D = Shaft diameter (m)
D_o= Sleeve outer diameter (m)
T = Torque capacity (N-m)
b = Width of key (m)
L = Length of key (m)
P = Power transmitted (watt or in SI base units kg-m²-s^-3)
N = Shaft speed (rpm)
τ = Allowable shear stress (Pa)

Reference:

Mechanical Engineers Databook, Carvil