Force to Press Together Hub and Shaft Design Equations and Calculator

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Force to Press Together Hub and Shaft Design Equations and Calculator

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Interference Fit Force Required the Press Together Hub and Shaft Equations and Calculator

The axial force necessary to press shaft into hub under an interface pressure p_c
Eq. 1
F_a = π d_c l µ p_c

where

µ = coefficient of friction
µ = 0:085 to 0.125 for unlubricated surface
µ = 0.05 with special lubricants

The approximate value of axial force to press steel shaft into cast-iron hub with an interference SI Units
Eq. 2a
F = ( 4,137 x 10⁴ ) [ ( d_o + 0.3 d_c ) l δ ] / ( d_o + 6.33 d_c)

where d_o , d_c, l and δ in m, and F in N

The approximate value of axial force to press steel shaft into cast-iron hub with an interference USCS Units
Eq. 2b
F = 6,000 [ ( d_o + 0.3 d_c ) l δ ] / ( d_o + 6.33 d_c)

where d_o , d_c, l and δ in in, and F in tonf

The approximate value of axial force to press steel shaft in steel hub SI
Eq. 3a
F = ( 28.41 x x 10⁴ ) [ ( d_o² + 0.3 d_c² ) l δ ] / d_o²

where d_o , d_c, l and δ in m, and F in N

The approximate value of axial force to press steel shaft in steel hub USCS
Eq. 3b
F = ( 4,120 ) [ ( d_o² + 0.3 d_c² ) l δ ] / d_o²

where d_o , d_c, l and δ in in., and F in tonf

The transmitted torque by a press fit or shrink fit without slipping between the hub and shaft
Eq. 4
M_t = π d_c² l µ p_c / 2

where
µ = 0:10 for press fit
µ = 0:125 for shrink fits

The temperature t₂ in °C to which the shaft or shrink link must be heated before assembly
Eq. 5
t₂ ≥ ( 2 δ / ( α d_c ) + t₁ )

where
t₁ = temperature of hub or larger part to which shaft or shrink link to be shrunk on, °C
M_t = torque or twisting moment, Nm (lbf in)
d_o = hub diameter, m (in)
d_c = contact surface diameter, compressive, m (in)
p_c = contact pressure MPa (psi)
δ = total change in diameter (interference), m (in)
α = coefficient of linear thermal expansion, (m/m) / °C [(in/in)/°F]

Conversion

1 newton is equal to 0.00010197162129779283 tonf.
1 tonf = .00950965 N
1 tonf = 2,204.623 lbf

Source:

Machine Design Handbook 2nd Edition, 2001
Prof. Dr. K. Lingaiah
Former Principal, Professor and Head, Department of Mechanical Engineering
University Visvesvaraya College of Engineering, Bangalore University, Bangalore