Copy of Brakes New PFY

8/14/2019 Copy of Brakes New PFY

1/90

BRAKES Copyright Gautam Malik 2007C

Brake System

Fundamentals


2/90


Brake System Principles

Kinetic Energy

Mass

Weight

Speed

Inertia and

Momentum


3/90


Friction Principles

Kinetic and Static

Friction

Friction and Pressure Friction and Surface

Area

Coefficient of Friction Brake Fade


4/90


Friction Materials Characteristics

Resist Fading with

increased temp

Resist fading when wet

Recover quickly

Wear gradually

Quiet

Bonded or Riveted


5/90


Braking Dynamics

Weight Transfer

Weight Distribution

Braking Power

Friction Efficiency

Brake to Wheel

Wheel to Road Surface Traction Efficiency

Skidding


6/90


Braking System


7/90


Types of Brakes

Mechanical Brakes (uses string & cam arrangementseg. scooters, bikes)

Hydraulic Brake (Cars & jeeps)

Drum Brakes

Disc Brakes

Vacuum Assisted Brakes

Pneumatic Brakes using compressed air (Bus/truck)

Antilock Braking System (ABS)


8/90


Mechanical Brakes


9/90


HYDRAULIC BRAKES


10/90


Hydraulic Braking System


11/90


Hydraulic Principles

Fluids cannot be compressed

Fluids can transmit Movement

Acts Like a steel rod in a closed container

Master cylinder transmits fluid to wheel

cylinder or caliper piston bore.

Fluids can transmit and increase force Force

AreaPressure


12/90


The amount force is calculated

by multiplying the pressure

times the area

P X A = Force


13/90


Hydraulic pressure is distributed

equally in all directions


14/90


The hydraulic pressure is the same, but theThe hydraulic pressure is the same, but the

applied force can be changed by changingapplied force can be changed by changing

the piston size.the piston size.


15/90



16/90


Advantage by Hydraulics

1. As oil is used, so fluid link assists in braking even

longer wheel distances compared to mechanical

brakes.

2. The braking effort is also comparatively reduced

3. No abrupt failure

4. Robust construction (works well in rough

conditions)


17/90


Disadvantages

Prone to leakages

It uses a closed system of fluid movement

so is restricted to longer wheel distances


18/90


Brake Pedal

First Mechanical

Advantage is Drivers

foot

Length of Lever

determines force

applied

Uses Fulcrum Pedal Ratio

10

25:1 2.5 inches

50.5 inch


19/90


Brake Plumbing

Rigid steel brake linesare double wall

Flexible hoses connectrigid lines on vehicleto each wheel

Transmits hydraulic

fluid to each wheel


20/90


DRUM BRAKESDRUM BRAKES


21/90



22/90


Drum Brake System


23/90


Two different categories

of drum brakes Non-servo Servo


24/90



25/90


Non-Servo


26/90


Servo ActionThe rear shoe does most of the work


27/90

Non Servo brakelining

Servo Brake lining

Primary

Secondary


28/90


It is very important that the Primary shoe

is always facing toward the front of the

car

The Secondary shoes must always face

toward the rear of the car


29/90


DRUM WEAR

Worn Drums

Scored

Bell Mouthed

Concaved


30/90


Drum SizeWhy is this important?

Because of the surface

area for the friction fora particular powertransmission.

BRAKE DRUM


31/90


Master Cylinder


32/90



33/90



34/90


Pressure Control Valves


35/90


System in Conjunction


36/90


Wheel Cylinder

Wheel cylinder or

caliper pistons are

slave cylinders Change hydraulic

pressure back into

mechanical force

Can use one or two

cylinders at each

wheel


37/90


Wheel Cylinders


38/90


Axle Seals

Inside Leak

Outside Leak


39/90


Emergency Brake

Parking or Emergency Brake


40/90


Parking Brake Systems

Foot or Hand Brake

Are cable controlled

Several Styles As shown

Drum in hat

Driveline


41/90


Combination of Disc & Drum


42/90


Automotive Disc Brakes


43/90


44/90



45/90



46/90


Disc Brake Caliper Assembly


47/90


Sliding Caliper

Applies pressure to

two pads on opposite

sides of rotor

Caliper

Sliding

Fixed

Friction Materialexposed to air


48/90


Fixed Caliper

Applies two pistons to

opposite sides of rotor

Caliper staysstationary

Disc Brakes require

higher hydraulic

pressure


49/90


Mounting Brackets

Mounting Brackets are used to

hold the Caliperin place.

Other than keeping the surface

clean and free of rust and road

grime, there is very little to bedone with this part


50/90


Rotors

Rotors are metal discs supported by

the suspension. The Calipers

clamp on to them to slow their

rotation, and then slow or stop the

car


51/90


Vented Rotor

These arethe VENTS


52/90


Vented Rotors

Vented Rotors have Fins in the spaces

between their machined surfaces.

These spaces allow air to pass through,which helps to carry heat away.


53/90


Non vented Rotor

Non Vented Rotors are used on smaller

vehicles, and have no cooling fins


54/90


Non Vented Rotor


55/90


Calipers

Calipers are the housings that contain

the Pistons and the Brake Pads. The

Calipers are connected to the HydraulicSystem, and hold the brake pads to the

Rotor


56/90


Caliper Types

There are 2 types of Calipers

Fixed

Floating


57/90


Fixed Caliper

Fixed Calipers are disc brakes that use a

caliper that is FIXED in position and does

not slide. They have pistons on both sidesof the disc. There may be 2 or 4 pistons per

caliper


58/90


Fixed Caliper

Motorcycles and

some import trucks

and cars use this

type


59/90


Sliding Caliper

Much more common

Single Piston

Easier to work with

On inboard side of caliper


60/90


Clean, Floating Caliper


61/90



62/90


Floating Calipers


63/90


Operation

Piston applies

pressure to

Inboard pad. As

the pad contacts

the rotor, the

caliper slides

along the pins,pulling the

outboard pad into

contact.

Caliper

Rotor

Piston

Brake Pads

Brake

Line


64/90


Sliding caliper in operation


65/90


Parts of a Caliper


66/90


Seal

The rebuild kit will have a new

O ring, and a Dust Seal


67/90


Piston

The Piston surface should be smooth and

clean. This one is pitted, and needs

replaced.


68/90

Fixed CaliperFixed Caliper


69/90

FixedFixed

calipercaliper22

pistonpiston


70/90

FixedFixed

calipercaliper

44

pistonpiston


71/90

Floating

Caliper


72/90


Vacuum Assisted BrakesVacuum Assisted Brakes

Where effort required is comparativelyhigher we make use of engine vacuum toassist braking.


73/90


Location of componentsLocation of components


74/90



75/90


Released positionReleased positionReleased positionReleased position


76/90


Applied positionApplied positionApplied positionApplied position


77/90


VacuumCheck valve

optional

location


78/90


12 volt vacuum booster12 volt vacuum booster

for low vacuum enginesfor low vacuum engines

12 volt vacuum booster12 volt vacuum booster

for low vacuum enginesfor low vacuum engines


79/90


AIR POWERED BRAKES

In air powered brakes, air instead of

incompressible oil as in case of hydraulic

brakes is used as the working medium. Air is abundantly available , free & hence can

be discharged into atmosphere without any

concerns after utilizing.


80/90


Advantage by Pneumatics

1. As air can be used in an open loop, so can easily bedischarged after assisting in braking at even longer wheeldistances compared to hydraulic brakes.

2. Can be utilized where braking effort is more as manual

effort is assisted by the pressure of compressed air fromreservoir via a compressor which takes its power from thecompressor.


81/90


Disadvantages

Noisy

Costly compared to hydraulic system


82/90


(Antilock Braking System (ABS))


83/90


Why Required???

During extensive field trails of Braking System someserious facts came out.

1. While impulse/sudden braking the tires gets locked due

to braking action as a result vehicle doesnt stops due tomomentum & starts skidding.

2. This skidding makes the vehicle get out of control ofdriver.

3. Also if there has been a situation in which wheels do not

lock up, the stopping distance reduces compared to asituation in which wheels are locked & do not skid &therefore remains in control of driver.


84/90


ABS System


85/90


In antilock braking System this skidding of thevehicle is checked. There are load Speed &acceleration sensors installed which provides usefuldata to the ABS Control Module about the tractiveeffort & the speed of the wheels. Before locking upof the wheel, the ABS controller allows thealternate barking & releasing action on the wheelcylinders/braking pads of calipers which prevent thewheels from locking. With this system the vehicleremains in the control of the driver.


86/90


Advantages

No skidding

Better Control

Less stopping distances

Disadvantages

Costly


87/90


Diagnosis of Brakes

Several different types of Complaints

1. Noise

2. Pulsation

3. Pedal travel etc..


88/90


Brake Noise

Wear

Indicator


89/90


Brake Pulsation

Usually a

warped Rotor

Rotor needs

trued on a

brake lathe


90/90

THANK YOU

Copy of Brakes New PFY

Documents

Transcript of Copy of Brakes New PFY