DISC BREAKDISC BREAK

SUB BY:SUB BY:

► MD GHULAM SARWARMD GHULAM SARWAR

SUB TO :SUB TO :

► D.K.PARJAPATI&D.K.PARJAPATI&► D.K.RAMAND.K.RAMAN

OverviewOverview

► IntroductionIntroduction► Parts of disc break and systemParts of disc break and system► Working of disc breakWorking of disc break► Where disc brakes are usedWhere disc brakes are used► Materials and performanceMaterials and performance► Advantage Advantage ► DisadvantageDisadvantage

IntroductionIntroduction►A A disc brakedisc brake is a wheel brake which slows is a wheel brake which slows

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

History of disc breakHistory of disc break Disc style break development and are began in Disc style break development and are began in

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

Parts of disc breakParts of disc break

A) Master cylinderA) Master cylinder

B) PedalB) Pedal

C) VentsC) Vents

A

B

C

PartsParts

D) Brake padsD) Brake pads

E) CaliperE) Caliper

F) RotorF) RotorD

E

F

Master cylinderMaster cylinder

► It is the parts of disc breakIt is the parts of disc break

by which force is converted by which force is converted

into pressureinto pressure

Master CylinderMaster Cylinder

► Force is applied to brake pedal by driverForce is applied to brake pedal by driver► Primary piston moves, which in turn pressurizes fluid in front of the first piston. The 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 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.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 pressurized fluid in the brake lines then causes the brake pads to move into contact with the rotor.the rotor.

► The secondary and primary pistons are used to give the car essentially two braking systems. 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.Each controls two wheels. If one of the systems were the fail, the other can still stop the car.

Fapplied

Secondary

Primary

CaliperCaliper

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

Caliper TypesCaliper Types

There are 2 types of CalipersThere are 2 types of Calipers

► FixedFixed

►FloatingFloating

Fixed caliperFixed caliper

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

Fixed CaliperFixed Caliper

Motorcycles and some import trucks and cars use this type

Floating caliperFloating caliper

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

Caliper OperationCaliper Operation

► Step 1: Force is applied to by driver to the master cylinderStep 1: Force is applied to by driver to the master cylinder► Step 2: Pressure from the master cylinder causes one brake Step 2: Pressure from the master cylinder causes one brake

pad to contact rotorpad to contact rotor► Step 3: The caliper then self-centers, causing second pad to Step 3: The caliper then self-centers, causing second pad to

contact rotorcontact rotor

1 2 3

Caliper

Brake Fluid

Pads

Rotor

RotorsRotors

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

Rotor padRotor pad

► Rotor pad is provided friction force Rotor pad is provided friction force when is contact with rotorwhen is contact with rotor

► Work to slow or stop vehicleWork to slow or stop vehicle

VentsVents

► Vents are provided coolingVents are provided cooling► when generate heat due to frictionwhen generate heat due to friction

Break pedalBreak pedal

► It is the parts of disc breakIt is the parts of disc break

in which force applied byin which force applied by

driver.driver.

Type of discsType of discs

► Essentially there are four type discsEssentially there are four type discs

.Normal .Normal

. Drilled. Drilled

. Grooved. Grooved

. Dimpled. Dimpled

Normal discsNormal discs

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

Drilled discsDrilled discs

► The face of these discs are drilled all the way through mainly to 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 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 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 fade. The problem with drilled discs is that the holes can have a tendancy to start cracking and collect dust and debris.tendancy to start cracking and collect dust and debris.

This picture is of a motorcycle disc but the idea is similar on the car This picture is of a motorcycle disc but the idea is similar on the car discs.discs.I do not recommend using drilled discs as they are prone to cracking.I do not recommend using drilled discs as they are prone to cracking.

Grooved discsGrooved discs

►The face of these discs have diagonal lines cut into them, there are two The face of these discs have diagonal lines cut into them, there are two reasons for reasons for this.this.Firstly they allow the venting of brake pad gasses thus eliminating brake fade.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 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 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.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 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 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 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 hubthe brake dust to accumulate in the centre of the hub..

Dimpled discsDimpled discs

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

How a Brake System WorksHow a Brake System Works

working of disc break working of disc break ► Brake Pedal—force input to system from driverBrake Pedal—force input to system from driver

► Master cylinder—converts force to pressureMaster cylinder—converts force to pressure► Pressure is used to move brake pads into placePressure is used to move brake pads into place

► Brake Pads—provide friction force when in contact with rotorBrake Pads—provide friction force when in contact with rotor► Works to slow or stop vehicleWorks to slow or stop vehicle

► Caliper—holds pads and squeezes them against rotorCaliper—holds pads and squeezes them against rotor

► Rotor—spins with wheelRotor—spins with wheel► When used in conjunction with brake pads, slows vehicleWhen used in conjunction with brake pads, slows vehicle

► Vents—help provide cooling to brakeVents—help provide cooling to brake

AnimationAnimation

Adjustments?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

MaterialsMaterials

►Different materials have different Different materials have different coefficients of frictioncoefficients of friction

►Pad material can be chosen for Pad material can be chosen for performance or to create a balance performance or to create a balance between performance and durabilitybetween performance and durability

Materials ContinuedMaterials 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.

Advantage of disc breakAdvantage of disc break►A greater coefficient of friction between the A greater coefficient of friction between the

abrasive and the steel disc in comparison abrasive and the steel disc in comparison with friction pads on aluminum rims;with friction pads on aluminum rims;

► Independence from the weather and road Independence from the weather and road conditions;conditions;

►Do not get clogged with mud and snow;Do not get clogged with mud and snow;►Longer life abrasive pads and discs;Longer life abrasive pads and discs;►Greater braking power;Greater braking power;►Steel disks unlike the aluminum rims are not Steel disks unlike the aluminum rims are not

afraid of a strong warm-up during braking ;afraid of a strong warm-up during braking ;►High accuracy of dosing braking;High accuracy of dosing braking;

Disadvantage of disc breakDisadvantage of disc break►The price high;The price high;► Increased demands on the torsional rigidity Increased demands on the torsional rigidity

of suspension fork (do not recommend the of suspension fork (do not recommend the use of any fork with disc brake);use of any fork with disc brake);

►The complexity of installation, especially for The complexity of installation, especially for hydraulic systems;hydraulic systems;

►Limited maintainability in field conditionsLimited maintainability in field conditions；；►High load-spoke wheel set (in order to High load-spoke wheel set (in order to

reduce the diameter of the flanges on the reduce the diameter of the flanges on the hubs to increase);hubs to increase);

►Complexity of the replacement of abrasive Complexity of the replacement of abrasive pads pads

Uses of Disc BrakesUses of Disc Brakes

►Disc brakes are often on the front (and Disc brakes are often on the front (and sometimes on the rear) wheels of carssometimes on the rear) wheels of cars

►Do the real work of brakingDo the real work of braking

►Unlike drum brakes, do not self-Unlike drum brakes, do not self-energizeenergize

► Eliminates brake out of adjustmentEliminates brake out of adjustment► Internally sealed automatic adjusterInternally sealed automatic adjuster► Increased service intervalsIncreased service intervals► Integral molded friction padsIntegral molded friction pads► Simple pad exchange reduces service time by over 50 Simple pad exchange reduces service time by over 50

percent vs. drum brakes.percent vs. drum brakes.► Large useable pad material volumeLarge useable pad material volume► Released at all major axles and suspension suppliersReleased at all major axles and suspension suppliers► Choice of Aluminum or Steel hubsChoice of Aluminum or Steel hubs► Choice of Spindle TypesChoice of Spindle Types► Driver Comfort Enhances Driver RetentionDriver Comfort Enhances Driver Retention

Disc Brakes TodayDisc Brakes Today

Questions?Questions?