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2. DISC BREAK
SUB BY:
► MD GHULAM
SARWAR
SUB TO :
►
►
D.K.PARJAPATI&
D.K.RAMAN

3. Overview
► Introduction
► Parts of disc break and system
► Working of disc break
► Where disc brakes are used
► Materials and performance
► Advantage
► Disadvantage

4. Introduction
►A disc brake is a wheel brake which slows
rotation of the wheel by the friction caused by
pushing brake pads against a brake disc with a
set of calipers. This is connected to the wheel
and the axle. To stop the wheel, friction
material in the form of brake pads, mounted on
a device called a brake caliper, is forced
mechanically, hydraulically, or
electromagnetically against both sides of the
disc. Friction causes the disc and attached
wheel to slow or stop.

5. History of disc break
▪ Disc style break development and are began in england in
the 1890s. The first caliper-type automobile disc brake
was patented by Frederick William Lanchester in his
Birmingham factory in 1902 and used successfully on
Lanchester cars. However, the limited choice of metals in
this period meant that he had to use copper as the braking
medium acting on the disc. The poor state of the roads at
this time, no more than dusty, rough tracks, meant that the
copper wore quickly, making the disc brake system non-
viable. It took another half century for Disc-style brakes
development and use began in England in the his
innovation to be widely adopted.

6. Parts of disc break
▪ A) Master cylinder
▪ B) Pedal
▪ C) Vents
A
B
C

7. Parts
▪ D) Brake pads
▪ F) Rotor
D
E
F
▪ E) Caliper

8. Master cylinder
► It is the parts of disc break
by which force is converted
into pressure

9. Master Cylinder
►
►
►
►
Force is applied to brake pedal by driver
Primary piston moves, which in turn pressurizes fluid in front of the first piston. The
secondary piston and primary piston are connected through a spring. As the primary
piston moves, it causes the secondary piston to move and pressurize fluid in front of it.
The pressurized fluid in the brake lines then causes the brake pads to move into contact
with the rotor.
The secondary and primary pistons are used to give the car essentially two braking
systems. Each controls two wheels. If one of the systems were the fail, the other can
still stop the car.
Fapplied
Secondar
y
Primary

10. Caliper
►The brake caliper is the assembly which
houses the brake pads and pistons. The
pistons are usually made of plastic,
aluminium or chrome-plated steel.

11. Caliper Types
There are 2 types of Calipers
► Fixed
►Floating

12. Fixed caliper
►A fixed caliper does not move relative to the
disc and is thus less tolerant of disc
imperfections. It uses one or more single or
pairs of opposing pistons to clamp from
each side of the disc, and is more complex
and expensive than a floating caliper.

13. Fixed Caliper
Motorcycles and
some import trucks
and cars use this
type

14. Floating caliper
►A floating caliper (also called a "sliding
caliper") moves with respect to the disc,
along a line parallel to the axis of rotation of
the disc; a piston on one side of the disc
pushes the inner brake pad until it makes
contact with the braking surface, then pulls
the caliper body with the outer brake pad so
pressure is applied to both sides of the disc.

15. Caliper Operation
►
►
►
Step 1: Force is applied to by driver to the master cylinder
Step 2: Pressure from the master cylinder causes one brake pad to
contact rotor
Step 3: The caliper then self-centers, causing second pad to contact
rotor
2 3
Caliper
Brake
Fluid
1 Pads
Rotor

16. Rotors
Rotorsare metal discs supported by
the suspension. The Calipers
clamp on to them to slow their
rotation, and then slow or stop the
car

17. Rotor pad
►Rotor pad is provided friction force when is
contact with rotor
► Work to slow or stop vehicle

18. Vents
► Vents are provided cooling
► when generate heat due to friction

19. Break pedal
► It is the parts of disc break
in which force applied by
driver.

20. Type of discs
► Essentially there are four type discs
.Normal
. Drilled
. Grooved
. Dimpled

21. Normal discs
►
Exactly as you have on your car as standard, flat faced discs. They have more
surface area touching the pads when the brakes are applied so initially have better
braking power.
The problem with normal discs is that as they heat up you can get a build up of
gas between the pad and the disc which causes brake fade and pad glazing. The
extra heat can also warp the discs if they are poorly made or have been paired
with inappropriate pads.

22. Drilled discs
► The face of these discs are drilled all the way through mainly to increase surface
area so they can rid themselves of heat quicker. The holes also go a little way to
stopping the gas build up that causes brake fade. The problem with drilled discs is
that the holes can have a tendancy to start cracking and collect dust and debris.
This picture is of a motorcycle disc but the idea is similar on the car discs.
I do not recommend using drilled discs as they are prone to cracking.

23. Grooved discs
►
The face of these discs have diagonal lines cut into them, there are two reasons
for this.
Firstly they allow the venting of brake pad gasses thus eliminating brake fade.
They also eject brake pad dust to stop glazing of the pad. This keeps the pad face fresh allowing better
braking. The problem is that grooved discs have a tendancy to be louder when the brakes are applied
due to the scrubbing of the pads.
Discs with grooves should be installed a certain way round. As the disc rotates in its
normal direction, the groove should be spinning outwards. This allows the brake dust
to be ejected away from the hub. Putting them on rotating the wrong way can allow
the brake dust to accumulate in the centre of the hub.

24. Dimpled discs
►The dimples in a disc clear debris from the
pad but the main reason is to reduce
weight.

25. How a Brake System Works

26. working of disc break
► Brake Pedal—force input to system from driver
► Master cylinder—converts force to pressure
► Pressure is used to move brake pads into place
► Brake Pads—provide friction force when in contact with rotor
► Works to slow or stop vehicle
► Caliper—holds pads and squeezes them against rotor
► Rotor—spins with wheel
► When used in conjunction with brake pads, slows vehicle
► Vents—help provide cooling to brake

27. Animation

28. Adjustments?
•Disc Brakes will automatically
self-adjust.
•As the Pads wear, the caliper
piston will not retract as far
•This leaves a larger amount of
brake fluid in the caliper, causing
the master cylinder level to lower

29. Materials
►Different materials have different
coefficients of friction
►Pad material can be chosen for
performance or to create a balance between
performance and durability

30. Materials Continued
►
►
►
Asbestos brakes were used for years because of their extremely high friction
coefficient, but advances in science has shown that it is a cancer causing
substance.
Performance pads often include small pieces of metal in the pads to aid in the
pads stopping power. The metal needs to be softer than the rotor, to ensure
that the rotor is not damaged over long periods of use.
The friction coefficients in the table are representative of dry conditions. If the
rotor and pad are moist, the systems stopping power is greatly reduced until
the moisture can be burned off.

31. Advantage of disc break
►A greater coefficient of friction between the
abrasive and the steel disc in comparison with
friction pads on aluminum rims;
►Independence from the weather and road
conditions;
►Do not get clogged with mud and snow;
►Longer life abrasive pads and discs;
►Greater braking power;
►Steel disks unlike the aluminum rims are not
afraid of a strong warm-up during braking ;
►High accuracy of dosing braking;

32. Disadvantage of disc break
►The price high;
►Increased demands on the torsional rigidity of
suspension fork (do not recommend the use of
any fork with disc brake);
►The complexity of installation, especially for
hydraulic systems;
►Limited maintainability in field conditions ；
►High load-spoke wheel set (in order to reduce
the diameter of the flanges on the hubs to
increase);
►Complexity of the replacement of abrasive pads

33. Uses of Disc Brakes
►Disc brakes are often on the front (and
sometimes on the rear) wheels of cars
►Do the real work of braking
►Unlike drum brakes, do not self-energize

34. ► Eliminates brake out of adjustment
► Internally sealed automatic adjuster
► Increased service intervals
► Integral molded friction pads
► Simple pad exchange reduces service time by over 50
percent vs. drum brakes.
► Large useable pad material volume
► Released at all major axles and suspension suppliers
► Choice of Aluminum or Steel hubs
► Choice of Spindle Types
► Driver Comfort Enhances Driver Retention
Disc Brakes Today

35. Questions?