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^{\circ} \text { each, } D=10 in \text {. 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_{ avg } (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}