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Brake_squeal 部分翻译.doc

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BRAKE_SQUEAL 部分 翻译
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Brake squeal: a literature review 制 动尖叫 :文 献综 述 ? Antti Papinniemi a, ? Joseph C.S. Lai a , ? Jiye Zhao b , ? Lyndon Loader b? 声学与振动单元, 航空航天与机械工程学院, 大学学院, 新南威尔士大学, 澳大利亚国防军事 学院,堪培拉,ACT 2600 ,澳大利亚 ? PBR 汽车控股有限公司,264 东边界路,东 班特, 电话 3165 澳大 利亚 Abstract 摘要 Brake squeal , which usually falls in the frequency range between 1 and 16 kHz, has been one of the most difficult concerns associated with automotive brake systems since their inception. 制动尖叫的频 率通常在 1 到 16KHz 之间,它是 自汽车制动系统诞生以来与之相关的最难的问题之一。It causes customer dissatisfaction and increases warranty costs. 制动尖叫会导致客户的不满和维 修费用的增加。 Although substantial research has been conducted into predicting and eliminating brake squeal since the 1930s, it is still rather difficult to predict its occurrence. 虽然从上世纪 30 年 代以来对其进行了大量的研究来预 测和消除制动尖叫,但是它的发生仍然相当难预测。 In this paper, the characteristics and current difficulties encountered in tackling brake squeal are first described. 本 文中 , 第一次 提 到 了 解决 制 动 尖 叫 的特 点 和 难点 的 问 题。A review of the analytical, experimental and numerical methods used for the investigation of brake squeal is then given. 然后给出一份用于调查制动尖叫理 论的分析方法,实验方法和数学模拟的方法的综述。 Some of the challenges facing brake squeal research are outlined. 对 研究制动尖叫所面临的挑战 进行了 概述。 1. Introduction 介绍 Brake squeal has been one of the most difficult concerns associated with automotive brake systems since their inception 。、制动尖叫是自汽车制动系统 诞生以来与之相关的最难的问题之一。Research into predicting and eliminating brake squeal has been conducted since the 1930s [1] and [2]. 从上 世纪 30 年 代以来对于预测和消除制动尖叫的研究已经实施了。Initially drum brakes were studied due to their extensive use in early automotive brake systems. 最初, 对 于 鼓 式 制 动 器 的 研 究 是 由 于 它 们 在 早 期 汽 车 制 动 系 统 中 的 广 泛 运 用 。However, disc brake systems are used more extensively in modern vehicles and have become the focus of brake squeal research. 然而,盘式制动系统被更加广泛的 运用于现代车辆中并已经成为制动尖叫研究的重点。 Fig. 1 and Fig. 2 show a typical disc brake system with a “fist type” caliper design. 图 1 和图 2 给 出了一个典型的带有“拳头型”卡钳设计盘式制动系统。 A disc brake system consists of a rotor that rotates about the axis of the wheel. 盘式制动系统由一个围绕轴轮旋转的转子组成。 The caliper assembly is mounted to the vehicle suspension system through an anchor bracket. 制动钳 总成通过一个锚支架安装到车辆悬架系统上。 The caliper housing can slide on the anchor bracket through the two pins. 钳 壳体可以通过两个销钉在锚支架上 滑动。Brake pads with moulded friction material can also slide on the anchor bracket. A piston can slide inside the caliper housing. 模压摩擦材料 的刹车片也 可 在锚支架上滑动 。活塞 可以在卡钳壳体内滑动 。 When hydraulic pressure is applied, the piston is pushed forward to press the inner pad against the rotor and in the mean time, the housing is pushed in the opposite direction to press the outer pad against the rotor, thereby generating a braking torque. 当油压起 作用时, 推动活塞向前挤压与转子相对的内垫, 同时, 卡钳壳体按相反的方向挤 压转子的外垫。 Fig. 1. A typical ‘fist’ type brake system. 图 1. 一个典型的“拳头型”制动 系统 View thumbnail images 查看缩略图 Fig. 2. Schematic of a disc brake system. 图 2. 盘式制动系统的示意 图 View thumbnail images Like all the other applications with friction interface, noise and vibration are inherent by-products of brake application. 像 其他所有具有 摩擦界面的应用系统 一样, 噪音和振动是制动应用系统固有的 副产品 。 Brake noise and vibration has been classified according to its frequency as judder, groan, hum, squeal, squelch and wire brush [3]. 制动 振动 噪声根据 其频 率被分 为制 动 抖 动 ,制 动轰 鸣, 嗡 嗡声 , 制动 尖叫, 静噪 和钢丝 刷 (根据 文献 3 ) The squeal noise that is particularly annoying usually falls into a frequency range from 1 to 16 kHz. 特别 烦人的 尖叫噪声的频率范围通常在 1 到 16KHz 之间。Brake squeal is generated by the vibration of an unstable vibration mode of the brake system. 制动尖叫 是由制动系统的一种模式不稳定的振动所产生的。 In this condition the brake rotor can act as a loudspeaker since it has large flat surfaces that can readily radiate sound. 在 这种情况下的制动转子可以充当扬 声器, 因为它有大的平 面, 可随时散射声音。 The occurrence of brake squeal is a concern since it causes significant discomfort to the vehicle occupants and leads to customer dissatisfaction and increased warranty costs. 制 动尖叫的发 生是一个值得关注的问题, 因为它会导致驾乘人员的严重不适和 顾客的不满,并 增加了保修成本。 Unfortunately, the large body of research into brake squeal has failed to provide a complete understanding of, or the ability to predict its occurrence [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25] and [26]. 不幸的是,大量研 究投入还不能给出对于制动尖叫的完整的理解, 或者是预测它发生的能力 [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25] 和[26] 。 This is partly because of the complexity of the mechanisms that cause brake squeal and partly because of the competitive nature of the automotive industry, which limits the amount of cooperative research that is published in the open literature. 一部分 原因是由于 产生制动尖叫的机理复杂, 一部分原因是汽车行业的竞争性, 从而限制了合作研 究成果在公共文献上发表的数量。Although a comprehensive review of brake squeal was conducted by Yang and Gibson in 1997 [4], it was focussed to some degree on the material aspects of a brake system. 虽然杨和吉普森在 1997 年【4 】对制 动尖叫进行了 全面的综述, 它在一定程度上侧重于制动系统的材料方面。 The objective of this paper is to outline the characteristics and current difficulties encountered in tackling brake squeal and to review the analytical, experimental and numerical methods used for the investigation of brake squeal. 本文的目的是概述在处理制 动尖叫时特点和当前 遇到的困难, 并且综述用于调查制动尖叫理论的分析方法、 实验方法和数值模拟的方法。 2. Characteristics of brake squeal 制动尖叫的 特点 One of the biggest contributors to brake squeal is the friction material, since squeal excitation occurs at the friction interface, and it normally takes approximately 12 months to finalise a friction material selection. 因 为尖叫是在 摩擦界面被激发的, 所以制动尖叫的最大的贡献者之一是摩擦材料, 而摩擦材料 的选择一般需要 12 个 月来完成。 This certainly makes it very difficult to predict a priori the propensity of a brake system to squeal. 这无疑使得它很难去预测先 验制动系统尖叫的倾向。Also, often in the design of a brake system, priority is given to requirements such as braking performance, cost and ease of manufacture. 此外, 往 往在制动系统的设计中, 如制动的性能, 成本 和易于制造 等要求被给与优先考虑。 The common practice for the different components of a brake system to be manufactured by different suppliers further complicates matters. 通 常 一 个 制 动 系 统 的 不 同 零 部 件 由 不 同 的 制 造 商 制 造 时 问 题 进 一 步 复 杂化。The large number of vehicles produced means that even a low squeal propensity found during initial testing of a brake system can become a major concern once a vehicle is in production due to a much larger population size. 一旦汽车由于更大的人口 规模而被生产, 那么汽车的大量生产意味着, 即使尖叫 在 制 动 系 统 的 初 期 检 查 中 被 发 现 的 倾 向 低 也 是 一 个 重 大 的 问 题 。Modifications towards the end of development phase will have two potential risks: (1) leading to production delays and increased costs to both the brake and vehicle manufacturers and (2) leading to products not fully validated with potential field warranty concern. 对于 开发结束阶段的改动将带来两个潜在的风险:(1 )导致 生产延误和刹车与汽 车 制造商的成本的增加 (2 )导致产品在潜在的 保修问题领 域上验证不充分。The most significant complication in brake research is the fugitive nature of brake squeal; that is, brake squeal can sometimes be non-repeatable. 在制动的研 究中最 重要 的问 题是制 动尖叫 不易捕 捉 的性质 ,因 为 制动尖叫有时是不可重复的。There are many potential squeal frequencies (unstable modes) for a brake system. 一个 制动系统中有许多潜在的 尖叫频率 (不稳定的模式) 。 Each individual component has its own natural modes. 每 个单一 部件 都有 它自 己的 自然模 式 。 The number of modes for a rotor within human hearing range may be up to 80. 人类听觉 范围内的转子模式 的数量 可能高达 80.The modal frequencies and modal shapes of the rotor, caliper, anchor and pad will change once these parts are installed in-situ. 一旦转子,卡 钳 ,锚和垫 片这些部件安装在原位, 它们 的模态频率和模态形状会发生变化。 During a brake application, these parts are dynamically coupled together resulting in a series of coupled vibration modes, which are different from the component free vibration modes. 制动 应用中, 这些部件是动态耦合在一起, 从而产生一系列不 同于组件的自由振动模式的动态耦合模式。The addition of the friction coupling forces at the friction interface results in the stiffness matrix for the system containing unsymmetric off-diagonal coupling terms. 在摩擦界面增加的耦合摩 擦力 造成了系统刚度矩阵中含有非对称的非对角线的耦合项。From the stability point of view, this coupling is considered to be the root cause of the brake squeal. 从稳定的角度来看, 这种耦合被认定为制动尖叫的根源。 A brake system may not always squeal given the “same” conditions. 制动系统可能 并不总是在 “ 相同” 的条件 尖叫 。Alternatively, small variations in operating temperature, brake pressure, rotor velocity or coefficient of friction may result in differing squeal propensities or frequencies. 另外, 在 工作温度, 制动压力, 转子速度或 摩擦系数小的变化可能会导致不同的尖叫倾向频率。Fig. 3 and Fig. 4 show the percentage occurrence of brake squeal obtained at PBR Automotive Pty Ltd using a Rubore drag type noise dynamometer and an AK noise matrix for various brake pressures and temperatures respectively. 图 3 和图 4 显示 PBR 汽车控股有限公司 使用 Rubore 拖曳式噪音测 功机和 分别有各种制动压力和温度 的 AK 噪声模型获得制 动尖叫的发生 比例。It can be seen from Fig. 3 that there is no simple relationship between the percentage occurrence and frequency of the brake squeal and the brake pad pressure. 从图 3 可以看出,制 动尖叫 发生 的比例和频率 与刹车片的压力之间的 不是简单 的关系。 Similarly, the influence of temperature on both the occurrence and frequency of the brake squeal is quite complex (Fig. 4). 同样, 温度对制动尖叫的发生和频率的影响是相当复杂的 (图 4 ). Fig. 3. Variation of occurrences of brake squeal with frequency and brake pad pressure.图 3 。制动 尖叫出现的频率和刹车片压力的变化。Fig. 4. Variation of occurrences of brake squeal with frequency and temperature.图 4 。制动 尖叫出现的频率和温度的变化。Due to the above-mentioned difficulties in designing a noise free brake system, efforts to eliminate brake squeal have largely been empirical, with problematic brake systems treated in a case by case manner.在设计 无噪 音制 动系 统时, 由于 上述困难, 努力消除刹车噪音主 要是靠经验, 有问题刹车系统以个案的方式处理 。The success of these empirical fixes depends on the mechanism that is responsible for causing the squeal problem. 这些经验修复的成功取决于负责引 起尖叫问题的机制。 The most fundamental method of eliminating brake squeal is to reduce the coefficient of friction of the pad material [5], [6] and [7].消除制 动尖叫的最根本的方法是减少刹车片材 料 的 摩 擦 系 数[5][6][7] 。However, this obviously reduces braking performance and is not a preferable method to employ. 然而,这显然 会降低制动性能,也不是可以采用的最好方法。The use of viscoelastic material (damping material) on the back of backplate can be effective when there is significant pad bending vibration [8] and [9]. 当重要的刹 车片弯曲振动时,弹性材料(阻尼材料)的使用效果是显着的 。Changing the coupling between the pad and rotor by modifying the shape of the brake pad has also been found effective [10] and [11]. 通过修改刹车片的形状来修改垫片 和转子之间的联接也是显着的。Other geometrical modifications that have been successful include modifying caliper stiffness [12] and [13], the caliper mounting bracket [14] and [15], pad attachment method [16] and rotor geometry [17] and [18].其他已经取得成功的几何修改包括修改卡钳刚度 [12][13] ,卡钳安装支 架[14][15] , 垫片安装 方法[16] 和转子几何形状[17][18] 。3. Analysis of brake squeal 制动尖叫分析3.1. Analytical methods 分析方法 The earliest research into brake squeal suggested that the variation in the friction coefficient with sliding velocity was the cause [19]. 最早 研究表明, 有 滑 动 速 度 的 摩 擦 系 数 的 变 化 时 制 动 尖 叫 的 原 因[19] 。Not only is there a difference between the static and dynamic coefficient of friction, but it was thought the drop in kinetic friction with increased sliding velocity could lead to a stick-slip condition and produce self-excited vibration. 不仅静态和动 态之间的摩 擦系数不同,而且 伴随 滑动速度增加 的 动摩 擦系 数 的 下 降 可 能 产生 一个 粘- 滑条 件和自激振动。However, squeal has been shown to occur in brake systems where the coefficient of kinetic friction is constant [20], and has led to analysis of the geometrical aspects of a brake system. 然而,尖叫已经被证实发生在制 动系统动摩擦系数不变,并引起对制动系统几何形状方面的 分析。 Spurr proposed an early sprag-slip model that describes a geometric coupling hypothesis in 1961 [6].斯珀尔在 1961 年[6] 提出早期楔块—滑模型,介绍了几 何耦合假说。Consider a strut inclined at an angle θ to a sliding surface as shown in Fig. 5(a). 如图 5 ( a )所示,考虑 滑动表面上一个倾斜角为 θ的压杆。The magnitude of the friction force is given by where μ is the coefficient of friction and L is the load. 摩擦力的大小 由公式 给出,其中 μ是摩擦系数,L 是负载。It can be seen that the friction force will approach infinity as μ approaches cot θ. 可以 看出当 μ趋向于 cot θ 时摩擦力将 趋向于无穷大。When μ=cot θ the strut ‘sprags’ or locks and the surface can move no further. 当 μ=cot θ时楔紧或者锁紧 ,表 面不再能移动。 Spurr's sprag-slip model consisted of a double cantilever as shown in Fig. 5(b). 如图 5 (b )所示,斯伯尔的楔块 —滑动模型包含一个双悬臂。Here, the arm O′P is inclined at an angle θ′ to a moving surface. The arm will rotate about an elastic pivot O′ as P moves under the influence of the friction force F once the spragging angle has been reached. Eventually the moment opposing the rotation about O′ becomes so large that O″P replaces O′P, and the inclination angle is reduced to θ″. The elastic energy stored in O′ can now be released and the O′P swings in the opposite direction to the moving surface. The cycle can now recommence resulting in oscillatory behaviour. Fig. 5. (a) Single strut rubbing against moving surface; (b) sprag-slip system. 图 5 (a )单压 杆对移动表面的摩擦;(b )楔块—滑动系统 Others extended this idea in an attempt to model a brake system more completely. Jarvis and Mills used a cantilever rubbing against a rotating disc in 1963 [21], Earles and Soar used a pin-disc model in 1971 [22], and North introduced his eight-degree of freedom model in 1972 [23]. The culmination of these efforts was a model published by Millner in 1978 [24]. Millner modelled the disc, pad and caliper as a 6 degree of freedom, lumped parameter model and found good agreement between predicted and observed squeal. Complex eigenvalue analysis was used to determine which configurations would be unstable. Parameters investigated included the coefficient of pad friction, Young's modulus of pad material, and the mass and stiffness of caliper. Squeal propensity was found to increase steeply with the coefficient of friction, but squeal would not occur below a cut off value of 0.28. He found that for a constant friction value, the occurrence of squeal and squeal frequency depends on the stiffness of pad material (Young's modulus). Caliper mass and stiffness also displayed distinct narrow regions where squeal propensity was high. The common conclusions of these models are that brake squeal can be caused by geometrically induced instabilities that do not require variations in the coefficient of friction. Since these closed form theoretical approaches cannot adequately model the complex interactions between components found in practical brake systems, their applicability has been limited. However, they do provide some good insight into the mechanism of brake squeal by highlighting the physical phenomena that occur when a brake system squeals. 3.2. Experimental methods The frequencies of a squealing brake are highly dependent on the natural frequencies of the brake rotor [17]. Consequently it is of fundamental importance to be able to determine the vibration modes of the rotor. Not only will an understanding of the vibration modes of the rotor help predict how a brake system may vibrate, but it is also necessary in developing countermeasures
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