Drum Brake Analysis
Drum Brake Analysis
(OP)
I have an application for a drum brake where the brake shoes contacts the drum over an arc greater than 45°. The brake shoes pivot on the brake arms. Where is there literature with equations and analytical porcedures to determine forces (torques) applied to the drum face?
Thanks
Thanks





RE: Drum Brake Analysis
I have formula here for variuos types of brakes, for internally expanding shoe brakes usually found in vehicles,
which I think is what your after, the formula are as follows
torque for left hand shoe = TL = K*u*a*r*F/(b+K*u*c)
torque for right hand shoe = TR= K*u*a*r*F/(b-K*u*c)
total torque = TR+TL
where K= 4*sin q /(2*q + sin 2*q)
the shoe subtends an angle in side the drum of 2*q
K is a factor which is a function of angle of
contact.
a = lever arm distance ie from pivot to where load
is applied to the shoe
b = is from shoe pivot to centre of the drum
c = horizontal distance from shoe pivot to the
inside dia of drum
r = drum radius
u = coeff of friction
F = force applied
max pressure applied by shoe = Pm = TR/(2*u*w*r^2* sin q)
where w = width of shoe
average pressure applied by shoe = Pa = Pm/K
The drum in the example shown in my reference book is turning clockwise whilst looking directly inside the drum with cover removed.
hope this helps
regards desertfox
RE: Drum Brake Analysis
Thanks
RE: Drum Brake Analysis
I have formula for a double block brake, with blocks external to the drum, formula as follows:
friction torque = T=F*a*r*u*[(1/(c+u*b))+(1/(c-u*b))]
maxium pressure = P= F*a/((c-u*b)*A)
where F = force applied
a = lever arm distance ie pivot point to force
applied F
c= lever arm pivot point to centre of brake block
b = offset between pivot point of lever arm and
tangential point on drum o.d.
A = block contact area
u = coefficient of friction
regards desertfox
RE: Drum Brake Analysis