Design and Analysis of Disk Brake
Vishlawath Raju Ms G. Pranathi, M.Tech
M.Tech (CAD\CAM) Assistant Professor
Tudi Ram Reddy Institute of Technology and Science. Tudi Ram Reddy Institute of Technology and Science.
ABSTRACT: friction pad directly against the metal tread of the
One of the first steps taken to improve braking came wheels. In wet conditions these crude brakes would
in the early '70s when manufacturers, on a lose any effectiveness.
widespread scale, switched from drum to disc brakes.
1.2 HOW BRAKES WORK
Since most a vehicle's stopping power is contained in We all know that pushing down on the brake pedal
the front wheels, only the front brakes were upgraded slows a car to a stop. But how does this happen? How
to disc during much of this period. Since then, many does your car transmit the force from your leg to its
manufacturers have adopted four-wheel disc brakes wheels? How does it multiply the force so that it is
on their high-end and performance models as well as enough to stop something as big as a car?
their low-line economy cars.This project is done by
creating a tri dimensional model (model name) and 1.3 BRAKE BASICS
this model is generated by using design software When you depress your brake pedal, your car transmits
CATIA. CATIA is useful for designing different the force from your foot to its brakes through a fluid.
number of models as per the dimensions, as it is a Since the actual brakes require a much greater force
versatile application. The model should be analyzed than you could apply with your leg, your car must also
and measured which is designed in CATIA. The multiply the force of your foot. It does this in two
obtained model is taken and geometric views are ways:
generated and following screenshots are shown. Mechanical advantage(leverage)
Analysis of the design is obtained by using Ansys Hydraulic force multiplication
software and following results and tables are listed in
this project. 1.4 LEVERAGE
The pedal is designed in such a way that it can
INTRODUCTION multiply the force from your leg several times before
1.1 DISK BRAKE any force is even transmitted to the brake fluid.
Ever since the invention of the wheel, if there has been
"go" there has been a need for "whoa." As the level of 1.5 HYDRAULIC SYSTEMS
technology of human transportation has increased, the The basic idea behind any hydraulic system is very
mechanical devices used to slow down and stop simple: Force applied at one point is transmitted to
vehicles has also become more complex. In this report another point using an incompressible fluid, almost
I will discuss the history of vehicular braking always an oil of some sort. Most brake systems also
technology and possible future developments. Before multiply the force in the process
there was a "horse-less carriage," wagons, and other
animal drawn vehicles relied on the animals power to 1.6 FRICTION
both accelerate and decelerate the vehicle. Eventually Friction is a measure of how hard it is to slide one
there was the development of supplemental braking object over another. Take a look at the figure below.
systems consisting of a hand lever to push a wooden Both of the blocks are made from the same material,
Page 480
but one is heavier. I think we all know which one will shoes tightly against the disk. The friction between the
be harder for the bulldozer to push. shoes and the disk slows and stops the disk.
1.7 A SIMPLE BRAKE SYSTEM 1.11 TYPES OF DISK BRAKES
The distance from the pedal to the pivot is four times The Three Types Of Disk Brakes Are:
the distance from the cylinder to the pivot, so the force 1. FLOATING CALIPER DISK BRAKES
at the pedal will be increased by a factor of four before 2. FIXED CALIPER DISK BRAKES
it is transmitted to the cylinder. 3. SLIDING CALIPER DISK CALIPER
The diameter of the brake cylinder is three times the 1.12 MAIN PARTS:
diameter of the pedal cylinder. This further multiplies The main components of a disc brake are:
the force by nine. All together, this system increases The brake pads
the force of your foot by a factor of 36. If you put 10 The caliper, which contains a piston
pounds of force on the pedal, 360 pounds (162 kg) will The rotor, which is mounted to the hub
be generated at the wheel squeezing the brake pads.
1.13 BRAKE PAD
1.8 TYPES OF BRAKES
1. DRUM BRAKES
2. DISC BRAKES (CALLIPER BRAKES)
1.9 DRUM BRAKES:
The drum brake has two brake shoes and a piston.
When you hit the brake pedal, the piston pushes the
brake shoes against the drum This is where it gets a
little more complicated. as the brake shoes contact the
drum, there is a kind of wedging action, which has the
effect of pressing the shoes into the drum with more
force. The extra braking force provided by the
wedging action allows drum brakes to use a smaller
CALIPER AND ROTO
piston than disc brakes. But, because of the wedging
1.14 WORKING OF DISC BRAKES
action, the shoes must be pulled away from the drum
The caliper is the part that holds the break shoes on
when the brakes are released. This is the reason for
each side of the disk. In the floating-caliper brake, two
some of the springs. Other springs help hold the brake
steel guide pins are threaded into the steering-knuckle
shoes in place and return the adjuster arm after it
adapter. The caliper floats on four rubber bushings
actuates.
which fit on the inner and outer ends of the two guide
pins. The bushings allow the caliper to swing in or out
1.10 DISK BRAKE BASICS:
slightly when the brakes are applied
The disk brake has a metal disk instead of a drum.
It has a flat shoe, or pad, located on each side of the
1.15 FIXED-CALIPER DISK BRAKE
disk. To slow or stop the car, these two flat shoes are
This brake usually has four pistons, two on each side
forced tightly against the rotating disk, or rotor. Fluid
of the disk. The reason for the name fixed-caliperis
pressure from the master cylinder forces the pistons to
that the caliper is bolted solidly to the steering
move in. This action pushes the friction pads of the
knuckle. When the brakes are applied, the caliper
Page 481
cannot move. The four pistons are forced out of their friction braking system including automobiles, trucks,
caliper bores to push the inner and outer brake shoes in motorcycles, airplanes, and even bicycles.
against the disk. Some brakes of this type have used
only two pistons, one on each side of the disk Brake fade is caused by a buildup of heat in the
braking surfaces and the subsequent changes and
1.16 LIDING-CALIPER DISK BRAKE reactions in the brake system components and can be
The sliding-caliper disk brake is similar to the floating- experienced with both drum brakes and discbrakes.
caliper disk brake. The difference is that sliding- Loss of stopping power, or fade, can be caused by
caliper is suspended from rubber bushings on bolts. friction fade, mechanical fade, or fluid fade
This permits the caliper to slide on the bolts when the
brakes are applied. 1.20 BRAKE MODIFICATION TO REDUCE FAD
High performance brake components provide
1.17 SELF ADJUSTMENT OF DISK BRAKES: enhanced stopping power by improving friction while
Disk brakes are self-adjusting. Each piston has a seal reducing brake fade. Improved friction is provided by
on it to prevent fluid leakage. When the brakes are lining materials that have a higher coefficient of
applied, the piston moves toward the disk. This distorts friction than standard brake pads, while brake fade is
the piston seal. When the brakes are released, the seal reduced through the use of more expensive binding
relaxes and returns to its original position. This pulls resins with a higher melting point, along with slotted,
the piston away from the disk. As the brakes linings drilled, or dimpled discs/rotors that reduce the gaseous
wear, the piston over travels and takes a new position boundary layer, in addition to providing enhanced heat
in relation to the seal. This action provides self- dissipation. Heat buildup in brakes can be further
adjustment of disk brakes. addressed by body modifications that direct cold air to
the brakes.
1.18 EMERGENCY BRAKES
In cars with disc brakes on all four wheels, an 1.21 DISK BRAKE VENTS
emergency brake has to be actuated by a separate A moving car has a certain amount of kinetic energy,
mechanism than the primary brakes in case of a total and the brakes have to remove this energy from the car
primary brake failure. Most cars see a cable to actuate in order to stop it. How do the brakes do this? Each
the emergency brake. time you stop your car, your brakes convert the kinetic
energy to heat generated by the friction between the
Some cars with four-wheel disc brakes have a separate pads and the disc. Most car disc brakes are vented.
drum brake integrated into the hub of the rear wheels.
This drum brake is only for the emergency brake Brake fade caused by overheating brake fluid (often
system, and it is actuated only by the cable; it has no called Pedal Fade) can also be reduced through the use
hydraulics. of thermal barriers that are placed between the brake
pad and the brake caliper piston, these reduce the
1.19 BRAKE FADE transfer of heat from the pad to the caliper and in turn
Vehicle braking systemfade, or brakefade, is the hydraulic brake fluid. Some high-performance racing
reduction in stopping power that can occur after calipers already include such brake heat shields made
repeated or sustained application of the brakes, from titanium or ceramic materials. However, it is also
especially in high load or high speed conditions. Brake possible to purchase aftermarket titanium brake heat
fade can be a factor in any vehicle that utilizes a shields [6] that will fit your existing brake system to
Page 482
provide protection from brake heat. These inserts are Uniform braking from small fluctuations in
precision cut to cover as much of the pad as possible brake forces
Retardation values retained even under heavy
1.22 ADVANTAGES OF DISC BRAKES OVER stresses
DRUM BRAKES
As with almost any artifact of technology, drum brakes Why do disk brakes have higher safety reserves?
and disk brakes both have advantages and Minimal braking effect from high
disadvantages. Drum brakes still have the edge in temperatures and extreme driving
cheaper cost and lower complexity. This is why most requirements Minimal heat fading
cars built today use disk brakes in front but drum No brake disk distortion from extreme heat
brakes in the back wheels, four wheel disks being an due to internal ventilation with directional
extra cost option or shouted as a high performance stability and large power reserve under high
feature. Since the weight shift of a decelerating car stress
puts most of the load on the front wheels, the usage of The decisive safety aspects of the disk brake
disk brakes on only the front wheels is accepted design are shorter braking distances
manufacturing practice.
TESTING OF DISK BRAKES
Drum brakes had another advantage compared to early The individual components are subjected to extensive
disk brake systems. The geometry of the brake shoes test on the test bed. The optimum arrangement of
inside the drums can be designed for a mechanical components on the axle beam, operational reliability
self-boosting action. The rotation of the brake drum and convincing performance are requirements that
will push a leading shoe brake pad into pressing harder must be met prior series production.
against the drum. Early disk brake systems required an
outside mechanical brake booster such as a vacuum 2.1 Introduction To CAD/CAM/CAE
assist or hydraulic pump to generate the pressure for The Modern world of design, development,
primitive friction materials to apply the necessary manufacturing so on, in which we have stepped cant
braking force. be imagined without interference of computer. The
usage of computer is such that, they have become an
Why are disk brakes more efficient : integral part of these fields. In the world market now
Flat brake disk (axial brake) under high the competition in not only cost factor but also quality,
pressure versus round brake drum (radial consistency, availability, packing, stocking, delivery
brake) during braking etc. So are the requirements forcing industries to adopt
Full friction surface of the brake pad on the modern technique rather than local forcing the
plane brake disk. industries to adapt better techniques like CAD / CAM /
No loss of brake power due to overheating or CAE, etc.
partial contact from brake drum parts
expansion. 2.2 Need for CAD/CAE &CAM
The usage of CAD CAE & CAM have changed the
Why do disk brakes have a better braking behavior over look of the industries and developed healthy &
Driver friendly braking behavior. Sensitive standard competition , as could achieve target in lean
braking in all situations and better time and ultimately the product reaches market in
Sensitive brake application and better brake estimated time with better quality and consistency . In
feeling
Page 483
general view, it has lead to fast approach and creative 2.8 Fully Associative:
thinking. A CATIA model is fully associative with the drawings
and parts or assemblies that reference it. Changes to
2.3 Introduction to CATIA the model are automatically reflected in the associated
CATIA is a robust application that enables you to drawings, parts, and/or assemblies. Likewise, changes
create rich and complex designs. The goals of the in the context of the drawing or assembly are reflected
CATIA course are to teach you how to build parts and back in the model.
assemblies in CATIA, and how to make simple
drawings of those parts and assemblies. This 3. DESING ANALYSIS TO DEVELOP THE
course focuses on the fundamental skills and concepts WORK
that enable you to create a solid foundation for your Cylindrical Line
designs Figure: 3.5
2.5 Feature-based
Like an assembly is made up of a number of individual
parts, a CATIA document is made up of individual
elements. These elements are called features.
When creating a document, you can add features such
as pads, pockets, holes, ribs, fillets, chamfers, and
drafts. As the features are created, they are applied
directly to the work piece. Sketure Top View
Figure: 3.6
2.6 Parametric
The dimensions and relations used to create a feature
are stored in the model. This enables you to capture
design intent, and to easily make changes to the model
through these parameters.
2.7 Solid Modeling
3A solid model is the most complete type of geometric
model used in CAD systems. It contains a.7ll the
wireframe and surface geometry necessary to fully Brake Hole of Top View
describe the edges and faces of the model. In addition Figure: 3. 7
to geometric information, solid models also convey
their topology, which relates the geometry together.
For example, topology might include identifying
which faces (surfaces) meet at which edges (curves).
This intelligence makes adding features easier. For
example, if a model requires a fillet, you simply select
an edge and specify a radius to create it.
Page 484
Hole in Pad student can model any kind of geometry he sees
Figure: 3.8 necessary for his studied case.
Model (B4) > Steady-State Thermal (B5) > Solution
(B6) > Temperature > Figure
No. of Holes in Top View
Figure: 3.10 5. RESULT
Figure: 3.11
FIGURE 2
ANALYSIS:
Introduction:
This Tutorial wills use area by made file to speed up
the learning process for the student. This file is
provided in Para solid format. The intention of this
tutorial is to get the student to run a straight forward
simulation. By the end of this tutorial a check list for
the required procedure can be formulated by the
student. ANSYS as a software is made to be user-
friendly and simplified as much as possible with lot so
finter face options to keep the user as much as possible
from the hectic side of programming and debugging
process.
Why it is that such a simple model is used
During this tutorial as simple geometry is used, the
objective of that is that the student masters the steps to
get to run a simple simulation, once thats do ne the
Page 485
TABLE 15 Model (C4) > Modal (C5) > Solution (C6) > Total
Deformation 4
TABLE 17
6. CONCLUSION
Many trucks and buses are equipped with air actuated
sliding caliper disk brakes
The high contact forces are transmitted mechanically
via needle mounted actuating device Depending on
size the actuating pressure is transmitted evenly to the
brake pads via one or two plungers.
The easy action, fully sealed guides between the
axially moving sliding caliper and fixed brake anchor
plate are maintenance free. Integrated automatic
adjustment with wear display. There are no brake
Page 486
shafts, external levers, or cylinder brackets, as the
brake cylinders are directly attached.
This project is done by creating a tri dimensional
model (model name) and this model is generated by
using design software CATIA. CATIA is useful for
designing different number of models as per the
dimensions, as it is a versatile application. The model
should be analyzed and measured which is designed in
CATIA. The obtained model is taken and geometric
views are generated and following screenshots are
shown. Analysis of the design is obtained by using
Ansys software and following results and tables are
listed in this project.
Author Details
Vishlawath Raju
M.Tech (CAD\CAM)
Tudi Ram Reddy Institute of Technology and Science.
Ms G. Pranathi, M.Tech
Assistant Professor
Tudi Ram Reddy Institute of Technology and Science.
Page 487
