Automobiles - Vehicle_Dynamics(19)

VehicleDynamicsFHRegensburg,UniversityofAppliedSciences

Reinforcements:steel,rayon,nylonRubber:natural/synthetic

Compounds:carbon,silica,chalk,...Softener:oil,resin

Vulcanization:sulfur,zincoxide,...MiscellaneousTireMass

16%38%30%10%4%2%8.5kg

Table2.2:TireComposites:195/65R15ContiEcoContact,Datafromwww.felge.de

2.1.3ForcesandTorquesintheTireContactArea

Inanypointofcontactbetweentireandtracknormalandfrictionforcesaredelivered.Accord-ingtothetire’spro ledesignthecontactareaformsanotnecessarilycoherentarea.Theeffectofthecontactforcescanbefullydescribedbyavectorofforceandatorqueinreferencetoapointinthecontactpatch.Thevectorsaredescribedinatrack- xedcoordinatesystem.Thez-axisisnormaltothetrack,thex-axisisperpendiculartothez-axisandperpen-diculartothewheelrotationaxiseyR.Thedemandforaright-handedcoordinatesystemthenalso xesthey-axis.

FxFyFzMxMyMz

longitudinalorcircumferentialforcelateralforce

verticalforceorwheelloadtiltingtorque

rollingresistancetorque

selfaligningandbore

torque

Figure2.1:ContactForcesandTorques

Thecomponentsofthecontactforcearenamedaccordingtothedirectionoftheaxes,Fig.2.1.Nonsymmetricdistributionsofforceinthecontactpatchcausetorquesaroundthexandyaxes.ThetiltingtorqueMxoccurswhenthetireiscambered.Myalsocontainstherollingresistanceofthetire.Inparticularthetorquearoundthez-axisisrelevantinvehicledynamics.Itconsistsoftwoparts,

Mz=MB+MS.(2.1)Rotationofthetirearoundthez-axiscausestheboretorqueMB.TheselfaligningtorqueMS

respectsthefactthatingeneraltheresultinglateralforceisnotappliedinthecenterofthecontactpatch.

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