BREAK SYSTEM

break system

A brake is a mechanical device which inhibits motion. Its opposite component is a clutch.A typical automotive brake system or braking system comprises of a brake device having different components, which are used for slowing or stopping down a vehicle. More precisely, these devices decrease or stop the speed of a moving or rotating body by absorbing kinetic energy mechanically. They are widely used in motor vehicles, buses, trucks, trains, airplanes, and other types of automobiles. The automotive brake system or automobile brake system is mainly used for helping the driver control the deceleration of the vehicle. It is one of the crucial systems, which is especially designed for decreasing the speed of the fast moving vehicle. A typical automotive brake system comprises of a brake device having different components, which are used for slowing or stopping down a vehicle. More precisely, these devices decrease or stop the speed of a moving or rotating body by absorbing kinetic energy mechanically or electrically. These automotive brake systems automatically control wheel slips and prevent the wheels from spinning. They are widely used in motor vehicles, buses, trucks, trains, airplanes, passenger coaches, trailers, and other types of automobiles. Automotive brake system or automobile brake system used in automobiles has come a long way in recent years. The adoption of anti lock brake systems along with the introduction of different brake parts made of carbon fiber, steel, aluminum etc have really provided better stopping performance in comparison with traditional ones.

WORKING

Brakes are designed to slow down your vehicle. The common cocept is that brakes squeeze against a drum or disc, and the pressure of the squeezing action is slows speed. This in fact is only part theoretical explanation. Brakes are essentially a mechanism to change energy types. When you are travelling at speed, your vehicle has kinetic energy. When you apply the brakes, the pads or shoes that press against the brake drum or rotor convert that energy into thermal energy via friction. The cooling of the brakes dissipates the heat and the vehicle slows down. It’s the First Law of Thermodynamics or  the law of conservation of energy. This states that energy cannot be created nor destroyed, it can only be converted from one form to another. In the case of brakes, it is converted from kinetic energy to thermal energy.

Drum brakes

Two semicircular brake shoes sit inside a spinning drum which is attached to the wheel. When you apply the brakes, the shoes are expanded outwards to press against the inside of the drum. This creates friction, which creates heat, which transfers kinetic energy, which slows you down. The example below shows a simple model. The actuator in this case is the blue elliptical object. As that is twisted, it forces against the brake shoes and in turn forces them to expand outwards. The return spring is what pulls the shoes back away from the surface of the brake drum when the brakes are released.

Disc brakes

Disc brakes are an order of magnitude better at stopping vehicles than drum brakes. Standard disc brakes have one or two cylinders in them – also know as one or two-pot calipers. Where more force is required, three, or more cylinders can be used. Sports bikes have 4- or 6-pot calipers arranged in pairs. The disadvantage of disc brakes is that they are extremely intolerant of faulty workmanship or bad machining. If you have a regular car disc rotor which is off by so much as 0.07mm (3/1000 inch) it will be Hell when you step on the brakes. When a brake lever or pedal is pressed, the push rod which is connected to lever or pedal and master cylinder piston pushes the master cylinder piston. This movement allows the master cylinder piston to slide and push the return spring inside the bore of master cylinder, which generates pressure in reservoir tank. At this moment a primary seal allows the brake fluid of reservoir tank to flow over it into the brake hosepipes. A secondary seal ensures that the brake fluid does not go other side. Then the fluid enters in to cylinder bore of caliper assembly via brake hosepipes and pushes the caliper piston or pistons. At this time the piston ring moves in rolling shape with piston. Then the caliper piston pushes brake pad. This movement causes brake pads to stick with brake disc which creates friction and stops the brake disc/rotor to rotate.  This way disk brake system stops or slows down the vehicle.When the brake lever or pedal is released the piston ring pushes the caliper piston back to cylinder bore of caliper till both, caliper piston and piston ring come into their original shape. At this time retraction spring pushes the brake pads to their original position. The return spring in master cylinder assembly pushes the master cylinder piston back into its original position and allows the fluid to flow back to reservoir via hosepipe and master cylinder bore.

Advantages

• Disk brake requires less  brake torque  to stop the vehicle compare to drum brake.

• Ease to  maintenance as disk brake is outside the wheel rim.

• It is less likely to skid compare to drum brake in wet condition.

• It has brake pad wear indicator which is not there in drum brake.

• It cools down faster compare to drum brake.

• If worn out brake shoes are not changed at proper time it can cut the brake drum in drum brake.disk brake does not have such problem.

• It generates less heat compare to drum brake for the same brake torque.

Disadvantages

• It is expensive compare to drum brake.

• It requires lot of effort at maintenance front like brake fluid (bleeding), change of brake pads etc compare to drum brake.

• Disk brake assembly has more moving parts and much complex than drum brake.