mech Disc brakes ppt.pptx

mech Disc brakes ppt.pptx

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  www.studymafia.org Submitted To: SubmittedBy: www.studymafia.org www.studymafia.org Seminar On DISK BRAKES
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  Introduction How They Work History Breakbasics Why Disk Brakes? Why are disk brakes more efficient? Types Advantages Disadvantages Conclusion References
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   Disc brakesare a brake system that slows a wheel’s rotation by squeezing an attached metal disc in a viselike hydraulic caliper.  Disc brakes use the same principle as bicycle handbrakes, but on a bike the brake pads press against the wheel itself.  On a car, the disc is part of the hub to which the wheel is mounted. The disc, technically called a rotor, is clearly visible through spoked wheels.
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   Ever sincethe invention of the wheel, if there has been "go" there has been a need for "whoa.“  As the level of technology of human transportation has increased, the mechanical devices used to slow down and stop vehicles has also become more complex.  Before there was a "horse-less carriage," wagons, and other animal drawn vehicles relied on the animal’s power to both accelerate and decelerate the vehicle.
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   Leverage  Hydraulics Friction
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  Why disk brakesin a truck or bus that travels in excess of 65 mph? Improved road handling, higher engine ratings and torque, reduced drag and rolling resistance resulting in faster acceleration and higher average speeds Higher vehicle speeds with full loads Higher traffic density, greater chances of emergency braking Extremely high kinetic energy needed to brake on wet roads, high front axle loads effecting vehicle directional stability
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  Flat brake disk(axial brake) under high pressure versus round brake drum (radial brake) during braking Full friction surface of the brake pad on the plane brake disk No loss of brake power due to overheating or partial contact from brake drum parts expansion Disk brakes can withstand higher loads and its efficiency is maintained considerably longer even under the highest stresses
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  Clear economic benefitsdue to long service life and reduced maintenance downtime Long service life of disks and pads versus drum brakes Shorter service downtime due to quick pad changes Good access for visual brake components checks Maintenance free brake components Optimized installation space in the wheel rim resulting in the largest possible brake disks and pads
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  Minimal braking effectfrom high temperatures and extreme driving requirements Minimal heat fading No brake disk distortion from extreme heat due to internal ventilation with directional stability and large power reserve under high stress The decisive safety aspects of the disk brake design are shorter braking distances
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   This typeof brake consists of a disc rotor that is rotating together with the wheel and a stationary brake caliper assembly equipped with brake pads. When pads are forced against the rotor from both sides, friction that is generated converts kinetic energy into heat, which causes the rotor and attached wheel to slow or stop.
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   This typeof disc brake has pistons on both sides of the brake rotor, and there are no moving parts in the caliper assembly other than the pistons themselves.  This type of caliper provides very even pressure distribution between pads and rotor providing better braking performance, especially under severe braking conditions.
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   For PassengerCars  Floating caliper type disc brakes have a piston (or pistons) only on the inner side of the rotor. When the brake is engaged, a piston pushes the inner brake pad against the rotor.  This generates a reaction force that moves the caliper itself along the slide pin, pushing the outer pad against the rotor to clamp it from both sides and achieve braking action.
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   Disc brakesare used mainly in passenger cars, but due to their stable performance at higher speeds and resistance to brake fade, they are gradually spreading into the commercial vehicle segment, where drum brakes were traditionally chosen for their long lining life.
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   Disk brakerequires less effort (brake torque) to stop the vehicle compare to drum brake.  It generates less heat compare to drum brake for the same brake torque.  Ease of maintenance as disk brake is outside the wheel rim.  It cools down faster compare to drum brake.  It is less likely to skid compare to drum brake in wet condition.
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   It isexpensive compare to drum brake.  More skills require to operate disk brake compare to drum brake that’s the reason why some people are not comfortable with disk brake.  If any air remains in disk brake system, it can cause accident as the brake will not work effectively.  Disk brake assembly has more moving parts and much complex than drum brake.
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   Many trucksand buses are equipped with air actuated sliding caliper disk brakes.  The high contact forces are transmitted mechanically via needle mounted actuating device Depending on size the actuating pressure is transmitted evenly to the brake pads via one or two plungers.
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   www.google.com  www.wikipedia.com www.studymafia.org