汽车制动中的NVH性能

NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Overview of Brake Noise)
刹车噪音概述
Factors Influencing Low Frequency Brake Noise
影响低频制动噪音的因素
Low Frequency Brake Noise
制动时发生长而尖的噪音是动态不稳定的一个现象，它以制动系统的一个或多个自然频率体现 •
The excitation comes from the friction couple.
这个尖锐的声音来自于摩擦耦合
•
The disc rotor is acting like a “ speaker”(sound wave radiated from the rotor surfaces). 刹车盘就好像是发音者（声波来自于对偶表面） Pads and rotor coupling has major impact on mid to high frequency (4 ~16 kHz) squeal. 对4-16khz频率范围内的长而尖的噪音来说盘和轴的耦合起着至关重要的作用
在刹车制动过程中 • Sensed as a shake or nibble through steering wheel, floor boards, dash panel, car seat, or
brake pedal
在方向盘，地板，冲击面板，车座或刹车踏板上感觉有振动 • Created by repetitive variation in torque output from the brake 由刹车系统中扭力输出量的重复变化引起
• 由于重新组装造成的损失
• Diminished customer confidence
• 客户流失的信誉损失
NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Definition of the Problem )
问题概述
HISTORY:来由 The first brake squeal on record was from a Sumerian quarry cart, 3,500 years ago
•Typically in the 5-60hz range
特别是在5-60hz的范围内
•Frequency varies with wheel speed 频率随车轮的转动速度而异 •Generally 1 to 2 pulsations per revolution but can reach up to 10 一般每旋转一周振动1-2次，但是也可以达到10次
嘎吱声是一个低频噪音，这种噪音在车内比车外听得清楚
Groan
Emanates from body structure in response to vibrations/pulsations created in brake
产生于结构本身在制动时对振动的反应
Frequency typically in range of 30 - 600 Hz
NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Definition of the Problem )
（问题概述）
Warranty Costs:保修成本
• Replacement of defective components
• 破损零部件的更换
• Lost productivity due to rework
NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Overview of Brake Noise)
刹车噪音概述
Frequency Range for NVH NVH的频率范围
NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Overview of Brake Noise)
近十年，在汽车行业中确保NVH性能已经是一个非常昂贵的问题。
More than $100 million is spent annually on brake NVH warranty work in North America alone.
光在北美市场，为了保障制动时的NVH性能每年的费用超过1亿美金.
NVH Issues in Automotive Brakes
汽车制动中的NVH性能 (Noise, Vibration, & Harshness) （噪音，振动，粗糙度）
Definition of the Problem 问题概述 Overview of Brake Noise 刹车噪音概述 Modeling & Simulation Strategy 建模和仿真策略 Survey of Measurement Methods 测量方法的调查 Elastic Property Measurements 弹性性能的检测方法
CFSMA , Guangzhou, China March 15 –18 2005
NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Definition of the Problem )
问题概述
Rationale:基本原理
NVH has been a costly warranty problem in the automotive industry for decades.
NVH Issues in Automotive Brakes 汽车制动中的NVH性能 (Noise, Vibration, & Harshness)
（噪音，振动，粗糙度）
CFSMA , Guangzhou, China March 15 –18 2005
Donald E. Yuhas Ph.D Industrial Measurement Systems, Inc. 2760 Beverly Drive #4 Aurora IL 60504 USA Dyuhas@imsysinc.com
Groan
NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Overview of Brake Noise)
刹车噪音概述
Brake Squeal 制动时长而尖的噪音
Squeal
Brake squeal is a phenomenon of dynamic instability that occurs at one or more of the natural frequencies of the brake system.
NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Overview of Brake Noise)
刹车噪音概述
Groan is a low frequency noise that is more distinctly heard inside the vehicle than outside the vehicle:
Rotor Thickness
Vane Pattern
Caliper Bridge
Anchor Bracket
Knuckle
Stiffness/mass
Suspension
Stiffness/mass
Pad Friction Material
Geometry
Damping
Hat Section Material
频率有时被轮胎更高的旋转速度要求所驱动
NVH Issues in Automotive Brakes
汽车制动中的NVH性能
(Overview of Brake Noise)
刹车噪音概述 Potential Contributors to Groan
对嘎吱声潜在的影响 Rotor Deformations - vane/channel surface ripples, grind/swirl surface finish patterns 刹车盘变形-轨道表面有波纹，表面加工时形成涡状型 Pad thermal deformation 刹车盘受热变形 Pad load pattern 刹车盘负荷曲线图 Friction film on rotor, Friction variation 刹车盘表面的摩擦膜， µ参数的变化 Pad physical property values, shear and compression 刹车盘的物理特性数值，剪切和压力 Friction coefficient versus speed, static / dynamic 对应于不同速度，动态或静态的摩擦系数 Caliper stiffness 卡钳硬度 Bushing stiffness 轴承硬度
刹车噪音概述
Roughness 5 -60 Hz
VeryBiblioteka BaiduLow Frequency Vibrations低频振动
DTV
Brake Roughness is the vehicle vibration, jerkiness, or pulsations. Also called Judder or Shudder 制动粗糙程度是车辆的振动，急促的跳动或有节奏的跳动。也称之为急剧的颤动。 •During a braking stop
•
•
Low frequency (1 ~ 3 kHz) squeal typically involves caliper, anchor bracket, knuckle and suspension, in addition to pads and rotor.
除了刹车片和刹车盘外，对1-3khz的低频噪音来说还包括了卡钳，托架，联结点和悬挂物的影响
Lumped parameter Models; Individual Component Simulation Models; Non- contact Measurements; Automated Data Acquisition 1990’ s 集中参数测量模式；独立的元件仿真模式；无接触测量方法；数据的自动获取和积累 2000’ s Large Systems Simulations; Improve Friction Material Characterization; Non-linear Behavior 2000’ s 大容量系统的仿真；提高摩擦材料性能；非线性的性能参数
典型的频率范围是在30-600Hz
Frequency content usually controlled by resonance modes in body and suspension system components
频谱通常由主件和悬挂系统部件的共鸣形式所决定
Frequency sometimes driven by higher order of wheel rotational speed
第一个有记载的刹车尖锐的噪音是3500年前，来自Sumerian的采石机
Modern Era:现代发展
1908 1908 1938 1938 1980’ s 1980’ s 1990’ s Herbert Frood patents first asbestos brake linings Herbert Frood 率先取得了石棉刹车片的专利。 Noise (squeal) identified as a problem 噪音（尖锐型的）被视为一个问题 NVH issues associated with the formulation of non-asbestos organic (NAO) pads leads to new measurement & analysis methods 与无石棉配方的刹车盘相关的NVH性能引发了一种新的检测和分析方法