4-5BrakingProportioningBalancing the brake outputs on both the front and rear axlesis achieved by“proportioning"the pressure appropriatelyforthe foundation brakes installed on the vehicle.It is well recognized that the preferred design is to bringboth axles up to the lockup point simultaneously.1.Vertical forces given by the ground when vehicle brakes-FziandFz2GFw(ignored)F(b+zh.)2g2duGF-zh.zgZ2OLdt6FxblaXb2FwhereZBrakingIntensityZ2F7
4-5 Braking Proportioning • Balancing the brake outputs on both the front and rear axles is achieved by “proportioning” the pressure appropriately for the foundation brakes installed on the vehicle. • It is well recognized that the preferred design is to bring both axles up to the lockup point simultaneously. 1 2 ( ) ( ) Z g Z g G F b zh L G F a zh L 1.Vertical forces given by the ground when vehicle brakes ——FZ1 and FZ2 FZ1 FZ2 FXb1 FX 2b G hg F ignored W ( ) Fj L a b du zg dt where z— Braking Intensity 1
Vertical forces given by the ground when vehicle brakesFziandFz2FFw(ignored)h60GFbFXb2aXb1F12LFZ12
FZ1 FZ2 FXb1 FX 2b G g h F ignored W ( ) Fj L a b Vertical forces given by the ground when vehicle brakes ——FZ1 and FZ2 2
1.Vertical forces given by the ground when vehicle brakes-Fziand Fz2if front lockup and rear lockup occur at the sametime or oneafteranother:GFw(ignored)FFboh.+ZPduLpg三dtphOTFxb2hFxblaFZ2F7
1 2 ( ) ( ) Z g Z g G F b h du L g dt G F a h L 1.Vertical forces given by the ground when vehicle brakes ——FZ1 and FZ2 if front lockup and rear lockup occur at the same time or one after another： FZ1 FZ2 FXb1 FX 2b G hg F ignored W ( ) Fj L a b 3
正常制动一条制动管路失效
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e"l"curve2.Idealproportioningcurve-Definition: A special curve which present therelationship between front and rear brakes brakingforce determined by the pressure applied to eachbrake and the gain of when front and rear lockupsoccurtogether"I"curveFu2欧5
2. Ideal proportioning curve——”I” curve Definition: A special curve which present the relationship between front and rear brakes braking force determined by the pressure applied to each brake and the gain of when front and rear lockups occur together. F1 F 2 " "I curve 5