Experimental And Control Analysis Of Vehicle Brake Judder

Brake judder refers to the lowfrequency vibration when the brake happens. The main characteristic of the brake judder is the violent shaking of the steering wheel, accompanied with vibrations in brake pedal, floor, and seats, which is one of the common braking faults. Brake judder seriously impacts the vehicle steering stability and comfort, speeds the aging and fatigue damage of related components, and even increases the possibility of the pilot fatigue and mistake.Brake judder is affected by many factors. According to the market complaint of a type of front disk brake vehicle, investigations are carried out to realize the demands of customers, work conditions and the specific vibration performances. The influence of driving condition and the characteristics of brake judder are studied through a series of road reappearance tests. The sources and the transfer paths of disc brake are studied by both experimental and theoretical methods, and there are three conclusions: (1) The steering wheel vibration frequency has an order relationship with wheel speeds, the first order is the most important, and the corresponding frequency range is 10 18Hz. (2) The brake judder is refers to the forced vibration of a resonance link, and the vibration source is the brake disc. DTV is the main factor. (3) Controlling vibration sources and reducing the amplifying influence of transfer path are the two effective manners to eliminate or reduce brake judder. As to transfer path, suspension system resonance frequency (10 20Hz) is unavoidable, the only way is to weaken the influence of transfer path by changing the location of connection point between suspension system and steering system and the corresponding structure, and adjusting the stiffness and damping in an allowing range; One of the most direct way is to change the vehicle suspension structure, for example, changing double wishbone independent suspension into McPherson suspension. For the suspension and steering construction of the car, there are no choices unless the controlling vibration sources; (4) For the controlling vibration sources, effective measures can be done from eight ways, such as design, manufacture, assembly protection, maintenance and so on.