Brake design – calculations

Brakes are machine elements that absorb kinetic or potential energy in the processes of slowing down or stopping a moving part. The absorbed energy is dissipated as heat. Break capacity depend upon unit pressure between the breaking surfaces, the coefficient of friction and ability of the brake to dissipate heat equivalent to energy absorbed. The performance of brake is similar to that of clutches except the clutches connect one moving part to another moving part, where brake connects a moving part to a frame.


Broad Classifications

  • External Shoe or Block Brakes
  • Single Block Brake
  • Double Shoe Brake
  • Internal Shoe Brake
  • Band Brake

Heat Generated = p Ac f V / 778 [Btu/min]
p = average contact pressure
Ac = contact area, in²
f = coefficient of friction
V = peripheral velocity of drum

MaterialMax Temp °FffPmax, psi
Metal on metal6000.25200
Wood on metal1500.2570
Leather on metal1500.3525
Asbestos on metal in oil5000.4050
Sintered metal on cast iron in oil5000.15400

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