The document discusses the design and analysis of disc brakes. It begins by introducing disc brakes and their components, which typically include cast iron or ceramic materials. It then discusses the braking requirements, principles of operation, and working of disc brakes. The document lists the main components of disc brakes and provides examples of applications. It notes the advantages of disc brakes, such as good braking at all speeds and lightweight, and disadvantages including higher cost compared to drum brakes. The document then analyzes theories related to disc brake pressure distribution and wear. It provides equations for calculating the coefficient of friction and heat dissipation of disc brakes.

1. Design And Analysis of Disc Brake
Mujahid Hussain 15-ME-92

2. INTRODUCTION
• The disc brake is a device used for slowing or
stopping the rotation of the wheel.
• A brake is usually made of cast iron or
ceramic composites include Carbon,
Aluminum, Kevlar and Silica.

3. BRAKING REQUIRMENTS
❑ The brakes must be strong enough to stop the
vehicle with in a minimum distance.
❑ The brakes must have well anti fade
characteristics i.e. their effectiveness should not
decrease with constant prolonged application.

4. PRINCIPLE
“The principle used is the applied force (pressure)
acts on the brake pads, which comes into contact
with the moving disc.At this point of time due to
friction the relative motion is constrained.”

5. WORKING
When the brakes are applied, hydraulically
actuated pistons move the friction pads in to
contact with the disc, applying equal and opposite
forces.

6. DISC BRAKE COMPONENT
Components:

7. APPLICATIONS
❑ MOTORCYCLES
❑ Bicycles
❑ Cars
❑ OTHERVEHICLES

8. ADVANTAGES
❑ Good braking at both low and high
speeds
❑ Light weight
❑ Anti-skid protection
❑ Simple installation

9. DISADVANTAGES
❑ It is expensive compare to drum brake.
❑ If any air remains in disk brake system, it
can cause accident as the brake will not
work effectively.
❑ Disk brake assembly has more moving
parts and much complex than drum brake.

10. (i) Uniform pressure theory:
When the mating component in clutch,
bearing are new, then the contact between
surfaces may be good over the whole
surface.
It means that the pressure over the rubbing
surfaces is uniform distributed.

11. The condition assumes that intensity of
pressure is same.
P = W/A =Constant
where,
W= load
A= area
This condition is not valid for old clutches,
bearings because mating surfaces may
have uneven friction.

12. Uniform wear theory:
When clutch, bearing become old after
being used for a given period, then all
parts of the rubbing surfaces will not
move with the same velocity.
The velocity of rubbing surface
increases with the distance from the
axis of the
rotating element.

13. It means that wear may be different at
different radii and rate of wear depends
upon the intensity of pressure (P) and the
velocity of rubbing surfaces (V).
It is assumed that the rate of wear is
proportional to the product of intensity of
pressure and velocity of rubbing surfaces.
This condition assumes that rate of wear
is uniform;
P*r = Constant; where, P = intensity of
pressure, r = radius of rotation.

14. Coefficient of friction of disc brake can be
calculated by
C = T/(re* μ*n)
Where,
C = brake clamp load
re = effective radius
n = No. of friction faces
μ = Coefficient of friction

15. Heat Dissipation in brakes

16. Cont.
Above eq. can be written as
The effect of speed can be included as
Braking power(heat) dissipated from exposed surfaces of
rotor can be calculated as:

17. Cont.

18. Cont.
 For continued braking, the average temperature
of a disc is calculated as

19. THANK YOU