BRAKES BY : VISHAKH V

BRAKING SYSTEM A BRAKE is a device which inhibits motion. BRAKING is the mechanism in the motor vehicle which is used to slowing down and stopping the vehicle to rest in the shortest possible distance.

STOPPING DISTANCE STOPPING DISTANCE depends upon Grip between the tyre and road surface. Tyre tread condition. Tyre inflation. Nature of road surface. Stopping Distance [D] = kV2 Where; k – constant depending upon the road and tyre inflation.(1/25 for 4 wheel & 1/12 for 2 wheel) v – velocity of vehicle per hour.

BRAKING EFFICIENCY Braking efficiency [η] =V2/3D where; V - velocity of the vehicle. D – stopping distance.

HISTORY OF BRAKES 1902 - Disc brakes were first used. 1918 - MALCOLM LOUGHEAD invented 4- wheel hydraulic brake systems. 1929 - 4-wheel hydraulic braking system were standard equipment on most high priced cars. Early 1950’s - CHRYSLER widely introduced the disc brake. 1964 - Disc brake was reintroduced by automaker Studebaker. 1969 – Ford uses ABS technology in cars. They were placed in THUNDERBIRD & CONTINENTAL MARK III.

PRINCIPLE Most commonly brakes use friction to convert kinetic energy into heat energy, though other methods of energy conversion may be employed. Since kinetic energy increases quadratically with velocity (K = mv2 / 2), an object traveling at 10 kilometers per second has 100 times more energy than one traveling at 1 kilometer per second, and consequently the theoretical braking distance, when braking at the traction limit, is 100 times as long. In practice, fast vehicles usually have significant air drag, and energy lost to air drag rises quickly with speed.

CHARACTERISTICS OF BRAKES Peak Force - The peak force is the maximum decelerating effect that can be obtained. Continuous Power Dissipation - Brakes typically get hot in use, and fail when the temperature gets too high. The greatest amount of power that can be dissipated through the brake without failure. Fade - As a brake heats, it may become less effective, called brake fade. Power - Brakes are often described as "powerful" when a small human application force leads to a braking force that is higher than typical for other brakes in the same class.

Durability - Friction brakes have wear surfaces that must be renewed periodically. Wear surfaces include the brake shoes or pads, and also the brake disc or drum. Weight - Brakes are often "added weight" in that they serve no other function. Further, brakes are often mounted on wheels, and unsprung weight can significantly hurt traction in some circumstances.

REQUIREMENTS It should work efficiently irrespective of road condition and quality. Retardation must be uniform throughout its application. Pedal effort must be within the convenient capacity of the driver. Must be reliable and should not be affected by heat, water & dust. Have minimum weight & long life. Should be easy to maintain and adjust. Noise & vibrations are to be minimum.

CLASSIFICATION OF BRAKES METHOD OF POWER Mechanical Brakes Vaccum Brakes Electrical Brakes Hydraulic Brakes Air Brakes Magnetic Brakes Air assisted hydraulic Brakes. METHOD OF APPLICATION Foot Brakes Hand Brakes

METHOD OF OPERATION Manual Servo Power METHOD OF BRAKING CONTACT Internal Expanding External Contracting METHOD OF APPLYING BRAKE FORCE Single acting brakes Double acting brakes

TYPES OF MECHANICAL BRAKES There are two types of mechanical brakes:- Drum Brakes. Disc Brakes.

DRUM BRAKES This type of brake works by using oil pressure. The pressure causes the rod to move, which then leads to the brake shoes squeezing. Friction on a rotating drum, which is attached to the wheel, will stop the car.

DISC BRAKES Disc brakes are designed using flat pieces of metal or other strong materials. The brake rotor applies spins with the wheel or axle. When you put your foot on the brake, brake pads on both sides will squeeze the brake disc, causing friction to stop or slow the wheel’s movement. Cars, motorcycles, and bikes are all commonly designed with this type of brake. The advantages that disc brakes have over drum brakes is that they dissipate heat better, provide more friction, are self cleaning, and are also known to tolerate water better.

ANTILOCK BRAKE SYSTEM An anti-lock braking system, or ABS is a safety system which prevents the wheels on a motor vehicle from locking up (or ceasing to rotate) while braking. A rotating road wheel allows the driver to maintain steering control under heavy braking by preventing a skid and allowing the wheel to continue interacting tractively with the road surface as directed by driver steering inputs. ABS offers improved vehicle control and decreases stopping distances on dry and especially slippery surfaces. However, on loose surfaces like gravel and snow-on-pavement, it can slightly increase braking distance while still improving vehicle control.