盘-销系统摩擦尖叫的时变性:发生机理与关键影响因素

Time-varying Characteristics of Frictional Squeal in Pin-on-disc System:Generation Mechanism and Key Impact Factors

为解释摩擦尖叫时变性的基本机制,建立盘-销系统并完成摩擦尖叫台架试验,成功反复再现间歇性和持续性尖叫。试验时,记录不同速度和法向力载荷工况下的摩擦噪声、动态接触作用力和销端部振动加速度信号。通过试验信号的小波分解、时频分析和馈入能量的计算,系统分析盘-销系统发生时变性摩擦尖叫的机理与因素。研究发现,摩擦尖叫的间歇性或持续性取决于摩擦接触法向力准静态分量的大小。当法向力准静态分量较小时,系统发生间歇性尖叫,反之则发生持续性尖叫。制动盘和销的模态耦合导致摩擦尖叫,尖叫频率会随着法向力准静态分量的变化成比例变化,且与摩擦接触力之间存在显著的滞环效应;能量馈入是产生摩擦尖叫的重要前提,而且馈入能量的变化导致摩擦尖叫声压幅值变化。

Abstract： To understand the basic mechanism of time-varying frictional squeal, a pin-on-disc system is established and the rig test of frictional squeal is carded out, in which both intermittent and continuous squeals are produced repetitively. During the tests, the squeal sound pressure, the three-directional contact forces and the acceleration of the pin end are sampled under various speeds and normal loads conditions. Through the wavelet analysis, time-frequency analysis and feed-in energy calculation, the generation mechanism and key impact factors of time-varying squeal is investigated. It is found that the intermittence or the continuity of squeal depends on the quasi static normal force. When the normal force is less, intermittent squeal will appear, and there will appear continuous squeal vice versa. The mode coupling between the disc and the clamped pin cause the squeal in the system. The squeal frequency changes with the quasi static normal force variation pro rata, and there is also an obvious hysteresis effect between the squeal frequency and the resultant contact force. Energy feed-in is the precondition of squeal generation, and the variations of feed-in power and energy result in the fluctuation of amplitude envelop of the squeal noise pressure.