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The vibration and noise of brakes have always been prevalent and difficult problems in the automobile industry and its related academic circle. The current study mainly focuses on the groan of the drum brake with a foldable cam lever actuation device strainer. The groan of the limit cycle generated by friction reappears after building its model in the ADAMS. Accordingly, a rigid flexible coupling model with a multi-layer friction plate is built. A simulation analysis shows that the model exhibits good braking stability and can reduce the amplitude of a brake groan through a comparison of the vibration characteristics of the drum brake and foldable cam lever with a conventional cam. A virtual prototyping analysis method for the dynamics characteristics of the foldable cam lever brake is also presented.

This paper presents multiple limit cycles oscillation of a brake system as a self-excited vibration with multiple amplitudes and frequencies that generates system noise. To determine the oscillation mechanism of the brake system, a dual-cylinder dual-pad brake system, with aid from the cooperating brake manufacturer, is proposed in this paper. The influence of initial braking speed, brake pressure, and friction coefficient between pad and disc on multiple limit cycle flutter is examined using numerical calculations. Result shows three limit cycle oscillation phenomena over a range of certain braking speeds with specific set of parameters. With decreasing initial braking speed, the amplitudes of large and small stable limit cycles increase, and the amplitude of the unstable limit cycle decreases. When the initial braking speed rises to the up critical value, both the unstable limit cycle and the small stable limit cycle disappear. The amplitude of multiple limit cycles, as well as the speed range where multiple limit cycles appear, increases with increasing brake pressure. The higher the kinetic friction coefficient, the larger the amplitude of multiple limit cycles and the higher the speed range of multiple limit cycles are.

Vibrations and noises induced by vehicle braking at low speeds are problems that have always blocked the development of the automotive industry, which the stick-slip vibrations of brake system are the major reason that causes the vibration and noise. Ref. [19] predicts chaotic stick-slip vibrations by introducing a torsional model. Additionally, in this article, we have established a four degree of freedom torsional braking model under pure braking, which is based on that reference. Since the chaotic stick-slip motions have been found based on a proper friction model through numerical method, from the bifurcation diagram of the relative velocity between the rotor and pad to corresponding brake pressure, we also found the dynamic characteristics of the system changing from doubling periodic bifurcation to chaos just by increasing the brake pressures. Any further numerical study showed that the doubling periodic bifurcation occurs both in stick phase and slip phase, which composed of the upper and lower bifurcation of the global bifurcation diagram. Thus, chaos and periodic motions in it can be identified by calculating Lyapunov exponents with ‘CLDYN’ method. At last, the effects of friction model parameters on bifurcation and chaos were studied, which provides important evidence theoretically showing that the decrease in braking vibrations and noises at low speed and the matching control of braking pressures.