《汽车理论》课程教学课件（英文讲稿）第6章 汽车平顺性 Ride Performance 6.3 Simplify of Automobile Vibration System and Vibration of Single Mass System（汽车振动系统的简化及单质量系统的振动）

6.3 Simplify of Automobile Vibration System and Vibration of Single Mass System汽车振动系统的简化及单质量系统的振动1.SimplifyofAutomobileVibrationSystem7freedommodel自由度m模型4wheels车轮，Ix lyZ7mi善V（

7 freedom model自由度 模型 4 wheels车轮，Ix Iy Z 1. Simplify of Automobile Vibration System

x() = y(I) => only vertical vibration"z"and pitch vibration"β" = simplify to plane model1）总质量保持不变m2f + m2r + m2c = m2m2f2）质心位置不变m2rm2ra -m2rb = 0aam2c3）转动惯量保持不变MI, = m2P, = m2ra2 + m,b?mmirp-p-m2 = m2baLm2r=mPm2e=m,4freedoms:2wheels,Iy,Zab

( ) ( ) vertical vibration" " and pitch vibration" " simplify to z plane model x I y I only     1）总质量保持不变 2）质心位置不变 3）转动惯量保持不变                      ab m m bL m m aL m m y y y 2 2c 2 2 2r 2 2 2f 2 1    4 freedoms：2 wheels, Iy,Z m m m m 2 f 2 r 2 c 2    2f 2 r m a m b   0 2 2 2 y y 2 2f 2 r I m m a m b    

sprung mass distribution coefficient悬挂质量分配系数：ε=abs=1→ connection mass联系质量m2。=0= The vertical movement of m2r and m2rare independent. = Two freedoms modelTwo freedoms: one wheel ,Z

Two freedoms：one wheel ,Z 2 sprung mass distribution coefficient y a b  悬挂质量分配系数：  2 2 2 1 connection mass 0 The vertical movement of and are independent. Two freedoms model c f r m m m      ＝ 联系质量

Dualmass vibrationsystem双质量振动系统m2rm21mmf

m1r m2r m2 f m1 f Dual mass vibration system 双质量振动系统

Singlemassvibration system单质量振动系统f < 5Hz = deflection of tyre is smallm2(f, : wheel natural frequency车轮固有频率,f～10～15Hz=Single mass vibration sys.9

( : wheel natural fr 5 deflection of t equency 10 ~ 1 yre is l 5 sma l t t Z f f z H f H    车轮  Single mass vibration 固有频率, ) sys. Single mass vibration system 单质量振动系统