Brake force analysis

Mechanical Advantage (pedal lever ratio) {MA}:

Booster Characteristics {B}:

Brake Factor {BF}:

Wheel Braking Force {Fbw}:

Exercise 1:

A brake system for a car has the following specifications:

Pedal:

L1 = 256.0 mm

L2 = 80.0 mm

Booster:

Booster characteristics (B) = 3.0

Master cylinder:

dm = 23.0 mm

Wheel cylinders:

(dw)f  =  45.0 mm

(dw)r =  20.0 mm

Wheel brakes:

(BF)f = 0.80

(rf)f  = 0.12 m.

(BF)r = 2.20

(rf)r = 0.15 m

Wheels:

Rw = 0.3 m

If the driver pressed the brake pedal with a pedal force of 500 N, Find:

A)

·    The brake mechanical advantage: MA

·    The brake hydraulic advantage: HAf , HAr

B)

·    Brake pedal push rod force: Fc,

·    Booster force: FB

·    Master cylinder force: Fm

·    Front wheel cylinder force: (Fw)f

·    Rear wheel cylinder force: (Fw)r

·    Front wheel friction force: (Ff)f

·    Rear wheel friction force: (Ff)r

·    Front wheel braking force: (Fbw)f

·    Rear wheel braking force: (Fbw)r

·    Car braking force: Fb = (Fb)f + (Fb)r = 2 (Fbw)f  + 2 (Fbw)r

C)

·    The brake circuit pressure: p

* Check the answers using the (the brake force analysis “Excel”)