Question 13.6: Design of a Disk Brake A disk brake has two pads of included...
Design of a Disk Brake
A disk brake has two pads of included angle \gamma = 60° each, D = 10 in. and d = 5 in. (Figure 13.14). Determine
a. The actuating force required to apply one shoe
b. The torque capacity for both shoes
Design Decision: Sintered metal pads and cast iron disk are used with f = 0.2 and p_{max} = 200 psi.
a. Equation 13.28 may be written in the form
F_{ a }=\int_{d / 2}^{D / 2} \pi p_{\max } d d r=\frac{1}{2} \pi p_{\max } d(D-d) (13.28)
F_a=\frac{\gamma}{360}\left[\frac{1}{2} \pi p_{\max } d(D-d)\right] (13.35)
Introducing the given numerical values,
F_a=\frac{60}{360}\left[\frac{1}{2} \pi(200)(5)(10-5)\right]=1309 lb
b. From Equation 13.30, we obtain
T=\frac{1}{4} F_a f(D+d)=F_a f r_{a v g} (13.30)
\begin{aligned} T &=\frac{1}{4} F_a f(D+d) \\ &=\frac{1}{4}(1309 (0.2)(10+5)=982 lb \cdot in . \end{aligned}