Brake force analysis

Mechanical Advantage (pedal lever ratio) {MA}:

Booster Characteristics {B}:

Hydraulic Advantage {HA}:

Brake Factor {BF}:

Wheel Braking Force {F_bw}:

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:

d_m = 23.0 mm

Wheel cylinders:

 (d_w)_f =  45.0 mm

 (d_w)_r =  20.0 mm

Wheel brakes:

(BF)_f = 0.80

(r_f)_f  = 0.12 m.

(BF)_r = 2.20

(r_f)_r = 0.15 m

Wheels:

R_w = 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: HA_f , HA_r

B)

· Brake pedal push rod force: F_c,

· Booster force: F_B

· Master cylinder force: F_m

· Front wheel cylinder force: (F_w)_f

· Rear wheel cylinder force: (F_w)_r

· Front wheel friction force: (F_f)_f

· Rear wheel friction force: (F_f)_r

· Front wheel braking force: (F_bw)_f

· Rear wheel braking force: (F_bw)_r

· Car braking force: F_b = (F_b)_f + (F_b)_r = 2 (F_bw)_f  + 2 (F_bw)_r

C)

· The brake circuit pressure: p

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