Disc Brake Torque
Disc Brake Torque
A disc brake converts motion to heat through friction pads pressing on a rotor; the torque sets the stopping ability.
The brake torque is T = μ·F·r·n. where μ is the friction coefficient, F the clamp force, r the effective radius and n the number of friction faces.
Inputs
mu := 0.4=0.4
F := 12 kN=12000 N
r := 0.12 m=120 mm
n := 2=2
Sum the friction torque over the faces.
T := mu·F·r·n=1152 Nm
Results
A larger radius or clamp force increases torque. The energy converted to heat must be dissipated, which is why brakes are ventilated.
Assumptions & limitations
- Constant friction coefficient.
- Uniform pad pressure.
- Effective radius at the pad centroid.