materials of brake pads.ppt
TRANSCRIPT
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By Phillip Holifield and Nick WeilSRJC, Engr 45, Fall 2009 Semester
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Disk brakes convert kinetic energy from the car into thermal energy by friction
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The brake fluid compresses the piston inside the brake caliper applying pressure to the brake pads
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Connected to the axel rotating at the same speed as the wheelGenerally made out of steelCommonly slotted or drilled for extra heat dissipation
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Fixed in the brake caliperVarious compounds of materials are usedWear over time and must be replaced
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Increase pad and rotor lifeReduce brake noiseCooling to prevent heat fadeMaximize braking forceFederal Safety RequirementsEnvironmental Impact
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Passenger Cars:
Low noise and wearTrucks and SUVs:
Heavier weight requires better brakingHigh Performance Cars:
Need maximum braking and cooling
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AsbestosSemi-MetallicNon-Asbestos OrganicsLow SteelCarbonExact composition of each manufacturers pads is a closely guarded secret
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Widely used in early disk brake applicationsGood for absorbing and dissipating heatAverage stopping powerAsbestos is legally regulate due to its carcinogenic propertiesNo longer used due to health risks
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Range from 30% to 65% metal and fillerDifferent pads use Steel, Iron, and CopperHarder material is very durable and has excellent heat resistanceCreates more noise and dustUsed in most cars and SUVs
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Low to medium coefficient of friction ~ 0.28 0.38Relatively high mu variation (temperature, duty cycle) Good fade characteristicsPoor wear at low temps.,
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Typically contain nonferrous metals, inorganic and organic fibers, abrasives, lubricants and property modifiers such as glass, rubber, kevlar and carbonTypically used in high performance carsAlso referred to as ceramics
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Low to medium-high coefficient of friction ~ 0.33 0.40.Excellent wear at lower temps. < 200C.Good for wheel dust. Relatively poor wear under heavy duty conditions and at higher friction levels.Good noise & roughness characteristicsCan have morning effectiveness noise squealing noise on first couple of brake applies in the morningMore expensive.
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Typically contain ferrous and nonferrous metals, inorganic and organic fibers, aggressive abrasives, lots of carbonaceous and sulfide lubricantsReplacing semi-metallic as the standard for passenger cars
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Higher coefficient of friction levels ~ 0.38 0.50Good pedal feel and braking confidenceGood fade and high speed performanceHigh pad/rotor wearGood for high speed wearLots of wheel dustInferior noise and life.
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Composite materials reinforced with carbon fibersUsed for both pads and rotorsUsed in Formula 1 and other race carsMajor manufacturers include Hitco, Brembo and Carbon Industries
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Light weight rotors weigh less than 1kgHigh coefficient of friction - can decelerate an F1 car at over 5GOperating temperature is around 800-1000CExtremely expensive to produce
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Text:http://en.wikipedia.org/wiki/Brake_padshttp://en.wikipedia.org/wiki/Disk_brakehttp://auto.howstuffworks.com/auto-parts/brakes/brake-types/disc-brake.htmwww.suscon.org/bpp/pdfs/OEBrakePads.pdfhttp://www.performancefriction.com/pages/pad_type.htmhttp://www.f1technical.net/articles/2
Images:http://stmarysjin.org.uk/hsw/gif/disc-brake3.jpghttp://www.akebonobrakes.com/oem/brake_products/images/3d_exploded_caliper.gifhttps://www.nzad.co.nz/store/images/standard%20brake%20rotor%20(Small).jpghttp://www.good-win-racing.com/miata/images/items/GWR-078.jpg