Download
materials of brake pads n.
Skip this Video
Loading SlideShow in 5 Seconds..
Materials of Brake Pads PowerPoint Presentation
Download Presentation
Materials of Brake Pads

Materials of Brake Pads

315 Vues Download Presentation
Télécharger la présentation

Materials of Brake Pads

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Materials of Brake Pads By Phillip Holifield and Nick Weil SRJC, Engr 45, Fall 2009 Semester

  2. How do disk brakes work? • Disk brakes convert kinetic energy from the car into thermal energy by friction

  3. Brake Caliper • The brake fluid compresses the piston inside the brake caliper applying pressure to the brake pads

  4. Brake Rotors • Connected to the axel – rotating at the same speed as the wheel • Generally made out of steel • Commonly slotted or drilled for extra heat dissipation

  5. Brake Pads • Fixed in the brake caliper • Various compounds of materials are used • Wear over time and must be replaced

  6. Design Challenges • Increase pad and rotor life • Reduce brake noise • Cooling to prevent heat fade • Maximize braking force • Federal Safety Requirements • Environmental Impact

  7. Design Challenges • Passenger Cars: • Low noise and wear • Trucks and SUV’s: • Heavier weight requires better braking • High Performance Cars: • Need maximum braking and cooling

  8. Brake Pad Materials • Asbestos • Semi-Metallic • Non-Asbestos Organics • Low Steel • Carbon • Exact composition of each manufacturer’s pads is a closely guarded secret

  9. Asbestos Pads • Widely used in early disk brake applications • Good for absorbing and dissipating heat • Average stopping power • Asbestos is legally regulate due to it’s carcinogenic properties • No longer used due to health risks

  10. Semi-Metallic Pads • Range from 30% to 65% metal and filler • Different pads use Steel, Iron, and Copper • Harder material is very durable and has excellent heat resistance • Creates more noise and dust • Used in most cars and SUV’s

  11. Semi-Metallic Pads • Low to medium coefficient of friction~ 0.28 –0.38 • Relatively high mu variation (temperature, duty cycle) • Good fade characteristics • Poor wear at low temps., <100C • Excellent wear at temps. over 200C • Good wear under heavy loads • Poor wear at high speeds • Generally inferior Noise, Vibration & Harshness compared to NAOs • Contains no copper • Low initial cost • High fluid temperatures can be an issue

  12. Non-Abestos Organic Pads • Typically contain nonferrous metals, inorganic and organic fibers, abrasives, lubricants and property modifiers such as glass, rubber, kevlar and carbon • Typically used in high performance cars • Also referred to as “ceramics”

  13. Non-Abestos Organic Pads • 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 characteristics • Can have morning effectiveness noise – squealing noise on first couple of brake applies in the morning • More expensive.

  14. Low Steel Pads • Typically contain ferrous and nonferrous metals, inorganic and organic fibers, aggressive abrasives, lots of carbonaceous and sulfide lubricants • Replacing semi-metallic as the standard for passenger cars

  15. Low Steel Pads • Higher coefficient of friction levels ~ 0.38 –0.50 • Good pedal feel and braking confidence • Good fade and high speed performance • High pad/rotor wear • Good for high speed wear • Lots of wheel dust • Inferior noise and life.

  16. Carbon Pads • Composite materials reinforced with carbon fibers • Used for both pads and rotors • Used in Formula 1 and other race cars • Major manufacturers include Hitco, Brembo and Carbon Industries

  17. Carbon Pads • Light weight – rotors weigh less than 1kg • High coefficient of friction - can decelerate an F1 car at over 5G • Operating temperature is around 800-1000°C • Extremely expensive to produce

  18. References • Text: • http://en.wikipedia.org/wiki/Brake_pads • http://en.wikipedia.org/wiki/Disk_brake • http://auto.howstuffworks.com/auto-parts/brakes/brake-types/disc-brake.htm • www.suscon.org/bpp/pdfs/OEBrakePads.pdf • http://www.performancefriction.com/pages/pad_type.htm • http://www.f1technical.net/articles/2 • Images: • http://stmarysjin.org.uk/hsw/gif/disc-brake3.jpg • http://www.akebonobrakes.com/oem/brake_products/images/3d_exploded_caliper.gif • https://www.nzad.co.nz/store/images/standard%20brake%20rotor%20(Small).jpg • http://www.good-win-racing.com/miata/images/items/GWR-078.jpg