A PROJECT REPORTOn

DISC BRAKE

SANJAY YADAV 0605640044PRAMOD KUMAR 0605640037SHUSEEL KUMAR YADAV 0605640056SUMIT KUMAR 1605640014RAJESH KUMAR BHARTI 2705640004

NORTHERN INDIA ENGINEERING COLLEGE, LUCKNOW

Types

Parking BrakeService Brake

– Hydraulic• Disc Brakes• Drum Brakes• Dual System

– Antilock Brake System (ABS)

Brake System Principles Kinetic Energy Mass Weight Speed Inertia and

Momentum

Typical System

Brake System• Drum Brake• Disk Brake

Introduction• DISC BRAKES consist of two pads that grasp a

rotating disk. The disk, or rotor, connects to the wheels by an axle. You control the grasping power. When you pull on the brake, the clamps come together on the disk, forcing it to stop spinning and causing your vehicle to slow down and eventually stop.

History• Disc-style brakes development and use began in

England in the 1890s. The first caliper-type automobile disc brake was patented by Frederick William Lanchester in his Birmingham, UK factory in 1902 and used successfully on Lanchester cars.

• It took another half century for his innovation to be widely adopted.Modern-style disc brakes.

1. 1949 – Crosley Hotshot2. 1953 – Jaguar C-Type racing car3. 1955 – Citroën DS

4. 1956 – Triumph TR35. 1965 – Rambler Marlin , Ford Thunderbird and so on…….Disc brakes offer better stopping performance than comparable drum brakes, including resistance to brake fade.Disc brakes were most popular on sports cars when they were first introduced, since these vehicles are more demanding about brake performance.Discs have now become the more common form in most passenger vehicles.

A cross-drilled disc on a modern motorcycle

Discs

• The design of the disc varies somewhat. Some are simply solid cast iron, but others are hollowed out with fins or vanes joining together the disc's two contact surfaces.

• This "ventilated" disc design helps to dissipate the generated heat and is commonly used on the more-heavily-loaded front discs.

• Discs may also be slotted, where shallow channels are machined into the disc to aid in removing dust and gas.

• Some discs are both drilled and slotted. On the road, drilled or slotted discs still have a positive effect in wet conditions because the holes or slots prevent a film of water building up between the disc and the pads.

• One reason is the disc's lack of self-assist makes brake force much more predictable, so peak brake force can be raised without more risk of braking-induced steering or jackknife on articulated vehicles.

• Another is disk brakes fade less when hot, and in a heavy vehicle air and rolling drag and engine braking are small parts of total braking force, so brakes are used harder than on lighter vehicles, and drum brake fade can occur in a single stop.

A mountain bike disc brake

A railroad bogie and disc brakes

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

Materials

• Different materials have different coefficients of friction

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

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.

Disc damage modes

• Discs are usually damaged in one of four ways: warping, scarring, cracking, or excessive rusting.

Warping• Warping is often caused by excessive heat. When

the disc's friction area is at a substantially higher temperature than the inner portion (hat) the thermal expansion of the friction area is greater than the inner portion and warping occurs.

Scarring• Scarring (US: Scoring) can occur if brake pads are

not changed promptly when they reach the end of their service life and are considered worn out.

Brake discs being polished after scarring occurred

Cracking• Cracking is limited mostly to drilled discs, which may

develop small cracks around edges of holes drilled near the edge of the disc due to the disc's uneven rate of expansion in severe duty environments.

Rusting• The discs are commonly made from cast iron and a

certain amount of what is known as "surface rust" is normal.

ComponentsPistons and cylinders• The most common caliper design uses a single

hydraulically actuated piston within a cylinder, although high performance brakes use as many as twelve.

Brake squeal• Sometimes a loud noise or high pitch squeal occurs

when the brakes are applied. Most brake squeal is produced by vibration (resonance instability) of the brake components, especially the pads and discs (known as force-coupled excitation).

Brake judder• Brake judder is usually perceived by the driver as

minor to severe vibrations transferred through the chassis during braking.

• Two distinct subgroups: hot (or thermal), or cold judder.

Brake dust• When braking force is applied, small amounts of

material are gradually ground off the brake pads. This material is known as "brake dust" and a fair amount of it usually deposits itself on the braking system and the surrounding wheel.

Parts of Braking System►Brake Pedal—force input to system from driver

►Design gives a Mechanical Advantage

►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

Brake pads• The brake pads are designed for high friction with

brake pad material embedded in the disc in the process of bedding while wearing evenly.

►Caliper—holds pads and squeezes them against rotor

Calipers• The brake caliper is the assembly which houses the

brake pads and pistons. The pistons are usually made of aluminum or chrome-plated steel. There are two types of calipers: floating or fixed.

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

►Vents—help provide cooling to brake

Caliper TypesThere are 2 types of Calipers• Fixed

Calipers are disc brakes that use a caliper that is FIXED in position and does not slide. They have pistons on both sides of the disc. There may be 2 or 4 pistons per caliper

• Floating Much more common Single PistonEasier to work withOn “inboard” side of caliper

Fixed Caliper

•Motorcycles and some import trucks and cars use this type

•Similar to bicycle brakes

Sliding Caliper

• Applies pressure to two pads on opposite sides of rotor

• Caliper Sliding Fixed

• Friction Material exposed to air

Fixed Caliper Applies two pistons to

opposite sides of rotor Caliper stays stationary Disc Brakes require

higher hydraulic pressure

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

1 2 3

Caliper

Brake Fluid

Pads

Rotor

• In a disc brake, the brake pads squeeze the rotor instead of the wheel, and the force is transmitted hydraulically instead of through a cable. Friction between the pads and the disc slows the disc down.

• A moving car has a certain amount of kinetic energy, and the brakes have to remove this energy from the car in order to stop it. Brakes convert the kinetic energy to heat generated by the friction between the pads and the disc. Most car disc brakes are vented.

• Vented disc brakes have a set of vanes, between the two sides of the disc, that pumps air through the disc to provide cooling.

Vented Rotors

Vented Rotors have Fins in the spaces between their machined surfaces. These spaces allow air to pass through, which helps carry heat away.

Nonvented Rotor

Non Vented Rotors are used on smaller vehicles, and have no cooling fins

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