Chapter twenty-three Steering system 同©大学 TONGII UNIVERSTTY Ideal relationship between deflection angle of both sides wheel Side force from ground >Steering trapezium should be designed reasonably. Steering wheel's deflection angle of inside and outside should meet: Deflect front Turning drive cota=cotβ+B/L wheel Ideal relationship between deflection angle of both sides steering wheel when double wheel's car is steering
第二十三章 汽车转向系统 Steering trapezium should be designed reasonably. Chapter twenty-three Steering system Deflect front wheel Turning drive Side force from ground Ideal relationship between deflection angle of both sides steering wheel when double wheel’s car is steering. Steering wheel’s deflection angle of inside and outside should meet: Ideal relationship between deflection angle of both sides wheel
Chapter twenty-three Steering system 同©大学 TONGII UNIVERSTTY Ideal relationship between deflection angle of both sides wheel Turnins radius efcar R=L/sina >Minimum turning radius ofcar:When the outside steering wheel's deflection angle comes to its maximum value amax turning radius comes to its minimum value: Rmin-L/sin(ama） R >Three-axle car which only use front axle to turn,as the middle and back wheel is always parallel,therefore no ideal turning center exists. >Equidistant bisector of middle and back Ideal relationship between deflection axle as a imaginary axle is used to angle of both sides steering wheel when calculate turning center. double wheel's car is steering
第二十三章 汽车转向系统 Minimum turning radius of car: When the outside steering wheel’s deflection angle comes to its maximum value αmax, turning radius comes to its minimum value: Rmin=L/sin(αmax) Turning radius of car R=L/sinα Three-axle car which only use front axle to turn, as the middle and back wheel is always parallel, therefore no ideal turning center exists. Equidistant bisector of middle and back axle as a imaginary axle is used to calculate turning center. Chapter twenty-three Steering system Ideal relationship between deflection angle of both sides steering wheel when double wheel’s car is steering. Ideal relationship between deflection angle of both sides wheel
Chapter twenty-three Steering system 同©大学 TONGII UNIVERSTTY Ideal relationship between deflection angle of both sides wheel >Three-axle car which take first and third axle as the steering axle. Suppose LI and L2 is the distance from first and third axle to second axle separately. >Four-axle car,which take first and second axle as the steering axle,take bisector between third and fourth axle as the steering basic line.LI and L2 donates the distance from first and second axle to the basic line separately. B >Front axle cota1=cot邶1+B/L1 >Back axle cotaz=cotB2+B/L2 a2 a B2 B Three-axle car which first and third axle steering Four-axle car which double front axle steering Steering diagram of multi-axle car >Steering trapezium should meet relative design demands
第二十三章 汽车转向系统 Three-axle car which take first and third axle as the steering axle. Suppose L1 and L2 is the distance from first and third axle to second axle separately. Front axle cotα1=cotβ1+B/L1 Back axle cotα2=cotβ2+B/L2 Steering trapezium should meet relative design demands. Four-axle car, which take first and second axle as the steering axle, take bisector between third and fourth axle as the steering basic line. L1 and L2 donates the distance from first and second axle to the basic line separately. Chapter twenty-three Steering system Steering diagram of multi-axle car Three-axle car which first and third axle steering Four-axle car which double front axle steering Ideal relationship between deflection angle of both sides wheel
Chapter twenty-three Steering system 同©大学 TONGII UNIVERSTTY Ideal relationship between deflection angle of both sides wheel B B az a B2 B Three-axle car which first and third axle steering Four-axle car which double front axle steering Steering diagram of multi-axle car >If L=L2=L/2,then a=02=a 1=$2=B >Minimum turning radius of car:Rmin=L/2sin(amax) >Only half of the same wheel base,front axle steering and double axle car's turning radius
第二十三章 汽车转向系统 If L1=L2=L/2,then α1=α2=α β1=β2=β Minimum turning radius of car: Rmin=L/2sin(αmax) Only half of the same wheel base, front axle steering and double axle car’s turning radius. Chapter twenty-three Steering system Ideal relationship between deflection angle of both sides wheel Steering diagram of multi-axle car Three-axle car which first and third axle steering Four-axle car which double front axle steering
Chapter twenty-three Steering system 同©大学 TONGII UNIVERSTTY Steering system angle ratio Steering wheel Steering gear Pitman arm Knuckle Steering transmission Steering gear mechanism angle ratio i angle ratio i2 Steering system angle ratio i >The more bigger the steering system angle ratio is,the more easy of steering.But steering sensitivity will lower. >For general car,steering transmission mechanism angle ratio i2 is about 1.Steering system angle ratio mainly depend on iTruck's angle ratio is 16 to 32.Car's angle ratio is 12 to 20
第二十三章 汽车转向系统 Steering system angle ratio Steering gear angle ratio iω1 Steering transmission mechanism angle ratio iω2 Steering system angle ratio iω iω= iω1*iω2 The more bigger the steering system angle ratio is ,the more easy of steering. But steering sensitivity will lower. Steering wheel Steering gear Pitman arm Knuckle For general car, steering transmission mechanism angle ratio iω2 is about 1. Steering system angle ratio mainly depend on iω1.Truck’s angle ratio is 16 to 32. Car ‘s angle ratio is 12 to 20. Chapter twenty-three Steering system