![]() Quoted from the SAE J2522 issued in 6/03, “The AK Working Group, which represents European manufacturers of friction linings and passenger car brakes, has developed an “AK Master” Standard in recent years. This is a basic dynamometer test used to characterize a pad materials friction couple with a given rotor material or substrate as in the special case of Carbon Ceramic rotors. Aluminum BerylliumĪn engineered alloy of Aluminum of exceptional stiffness to weight ratio used for Formula One calipers (and Ilmor/Mercedes engine blocks) in the late 1990s. ![]() See also “Transfer Layer”, “Brake Judder” and “Warped Rotors”. Brake judder is often called warped rotors. This pad material transfer if uneven is called pad material deposits which leads to brake judder. Wear of the rotor is almost nonexistent and pad wear comes from material being dissociated from the pad and rotor during the braking cycle. The intermolecular bonds that are broken, for the conversion of Kinetic to Thermal energy, are formed instantaneously before being broken again. The transfer layer of pad material, once evenly established on the rotor, is what rubs on the brake pad. Adherent friction is the mechanism where a transfer of a thin layer of brake pad material bonds (adheres) to the rotor face. The other type being Abrasive Friction (see Abrasive Friction). Adherent FrictionĪdherent friction is reference to one of two types of friction mechanisms. For example, one manufacturerʼs version applies the vehicle brakes when the vehicle is stopped or moving slowly and the automatic transmission is not in park but the driverʼs door is opened, anticipating that the driver has forgotten to set the parking brake if also not putting the transmission into park. The ABS system has added sensors and programming to control the vehicle tendency to lose traction, spin (yaw), act unfavorably or even anticipate actions required like increasing brake force output beyond that being directed by the driver to improve the handling of the vehicle in complex dynamic situations. Active HandlingĪctive Handling is an upcoming requirement for most new vehicles sold where the ABS systems basic components and programming are upgraded to act independent of driver brake system input. Most current passenger cars and trucks are fitted with ABS due to national and international laws, while even more elaborate system to control vehicle yaw or spin under extreme maneuvers is becoming a requirement. The pulsation the driver feels in the pedal is due to the design paradigm that uses the driverʼs pedal effort at any given instant to set the maximum pressure the system will yield. While ABS controllers are constantly being developed with other design strategies, historically the system feels like it is cycling due to the system programming and design that is controlling pressure at the wheel cylinder by first isolating the driver then cyclically lowering then raising pressure to correspond to what is required. Anti Lock braking systems sense the speed and rate of deceleration of each of the wheels of a vehicle independently and, through a microprocessor control system, act to prevent lock up of any of the tires under braking force by controlling the line pressure to the wheel that is approaching lock up. The small amount that is from the pad is due to the abrasive particles in the pad, as they wear down and become dull, being dislodged due to the force acting on them. The dust observed from brakes made from grey iron, no matter the color, is primarily from this rotor wear. Abrasive friction is the mechanism where abrasive particles in the pad are in a crystalline sense harder than the materials in the rotor. The other type being Adherent friction (see Adherent Friction). The term Abrasive friction is reference to one of two types of friction mechanisms. ![]() In a brake system, intermolecular bonds are broken for the conversion of Kinetic to Thermal energy.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |