Evaluation of the functional stability of brake properties of cars
Abstract
The stability of the torque generated by the braking mechanisms affects not only the magnitude of the stopping distance, but also the stability of the wheeled vehicle. The unevenness of the braking moments on the wheels of different sides leads to the appearance of an additional moment unfolding the car in the road plane. The fulfillment of the most stringent requirements of international and national standards for the effetiveness of vehicle braking is inextricably linked with the need to increase the energy intensity of the brakes. Excessive heating of the brake mechanisms leads to a decrease in the coefficient of friction μ of friction surfaces and increased wear of the friction linings. It should be noted that not all types of brake mechanisms used in motor vehicles can ensure an even distribution of generated heat over friction surfaces. In the disk brake there is a possibility of matching the wear characteristics of fractional materials, the law of contact pressure distribution with the sliding speed and the shape of the friction linings, which makes it possible to obtain a more uniform temperature distribution over the friction surfaces. The instability of the distribution of braking forces between the sides or wheels of the same axis, as already noted above, leads to the appearance of a turning point and the skidding of the car. The instability of the distribution of braking forces between the axles can lead to the danger of locking the rear wheels ahead of time, which, ultimately, also leads to a skidding of the car. The instability of the characteristics of the regulator of braking forces can lead to the appearance of a leading blocking of the rear wheels during emergency braking of the wheeled vehicle and skidding of the car. The reason for the occurrence of road accidents involving motor vehicles is the instability of their braking properties. As an example, the assessment of the functional stability of the stopping properties of cars of category M1 is given. Key words: functional stability, brake system, car testing, system reliability, standard.
