ABSTRACT
With this expression for pressure as a function of position, the torque on the drum will be the integral over the shoe length of the incremental friction force µ(prw-d ) acting on the surface of a drum of radius r. Thus
(1-5)
in which (sin )max denotes the maximum value of sin Φ within the range 1≤ ≤ 2. Integration of equation (1-5) yields
(1-6)
in which 1 is the angle from radius R between the drum axis and pivot A to the near edge of the drum sector subtended by the brake lining. As drawn in Figure 3, angle 2 is measured from radius R toward the far edge of the brake lining. Hence the angle subtended by the shoe is given by
(1-7)
To calculate the moment that must be applied about pivot A in Figure 3 to obtain the torque found by equation (1-6), we first calculate the moment reaction at the pivot due to both the incremental normal forces and the incremental friction forces acting on the lining. An equal and opposite moment must, of course, be supplied to activate the brake.
