What is a brake?

A brake is a device that resists and reduces motion of a mechanism. When the brake is engaged, it ¡°slips¡± until the driving mechanism stops. When the brake is disengaged, the mechanism can rotate freely. Brake is similar in principle to clutch. A clutch couples two mechanisms in order to transmit motion and power, while a brake ¡°couples¡± a mechanism to a fixed frame in order to reduce motion and power.

 

In a magnetic particle brake, an energized coil applies magnetic flux to magnetic particles in a powder cavity causing them to bind together. The binding of the particles causes the rotor and housing to experience drag which provides the torque for the rotor to decelerate. The strength of the binding (and accordingly, the deceleration torque generated) can be finely controlled by the varying the amount of current provided to the coil.