Angulos de las ruedas.pptx

8/10/2019 Angulos de las ruedas.pptx

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CATEDRA DE INTRODUCCIN A AUTOMOTORES

Facultad de Ingeniera

Universidad Nacional de Asuncin

Ing. Alejandro Mario

Ing. Juan Leopoldo Balsevich


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Convergencia-divergencia (toe in toe out)

Caster (avance)

Camber (pisada)


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The pivot pointsof the steeringare angledsuch that a line drawn through them

intersects the road surface slightly ahead ofthe contact patch of the tire on thepavement. The purpose of this is to provide adegree of self-centering for the steering - thewheel casters around so as to trail behind theaxis of steering. This makes a car easier todrive and improves its directional stability

(reducing its tendency to wander).
http://en.wikipedia.org/wiki/Ball_jointhttp://en.wikipedia.org/wiki/Steeringhttp://en.wikipedia.org/wiki/Directional_stabilityhttp://en.wikipedia.org/wiki/Directional_stabilityhttp://en.wikipedia.org/wiki/Steeringhttp://en.wikipedia.org/wiki/Ball_joint


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Excessive caster angle will make the steeringheavier and less responsive, although, in

racing, large caster angles are used toimprove camber gain in cornering. Casterangles over 7 degrees with radial tires arecommon. Power steering is usually necessaryto overcome the jacking effect from the highcaster angle.


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Camber angle alters the handlingqualities ofa particular suspension design; in particular,

negative camber improves grip whencornering. This is because it places the tireata better angle to the road, transmitting theforces through the vertical plane of the tirerather than through a shearforce across it.Another reason for negative camber is that arubber tire tends to roll on itself while

cornering.
http://en.wikipedia.org/wiki/Automobile_handlinghttp://en.wikipedia.org/wiki/Tirehttp://en.wikipedia.org/wiki/Shear_strengthhttp://en.wikipedia.org/wiki/Shear_strengthhttp://en.wikipedia.org/wiki/Tirehttp://en.wikipedia.org/wiki/Automobile_handling


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The inside edge of the contact patchwouldbegin to lift off of the ground if the tire had

zero camber, reducing the area of the contactpatch. This effect is compensated for byapplying negative camber, maximizing thecontact patch area. Note that this is only truefor the outside tire during the turn; the insidetire would benefit most from positive camber.
http://en.wikipedia.org/wiki/Contact_patchhttp://en.wikipedia.org/wiki/Contact_patch


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On the other hand, for maximum straight-line acceleration, the greatest traction will be

attained when the camber angle is zero andthe tread is flat on the road. Propermanagement of camber angle is a majorfactor in suspension design, and mustincorporate not only idealized geometricmodels, but also real-life behavior of thecomponents; flex, distortion, elasticity, etc.


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What was once an art has now become muchmore scientific with the use of computers,

which can optimize all of the variablesmathematically instead of relying on thedesigner's intuitive feel and experience. As aresult, the handling of even low-pricedautomobiles has improved dramatically inrecent years.


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Off-road vehicles such as agricultural tractorsgenerally use positive camber. In such

vehicles, the positive camber angle helps toachieve a lower steering effort.


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Also, some single-engined general aviationaircraft that are primarily meant to operate

from unimproved surfaces, such as bushplanesand cropdusters, have theirtaildraggergear's main wheels equipped withpositive-cambered main wheels to betterhandle the deflection of the landing gear, asthe aircraft settles on rough, unpavedairstrips.
http://en.wikipedia.org/wiki/Bush_planehttp://en.wikipedia.org/wiki/Bush_planehttp://en.wikipedia.org/wiki/Aerial_applicationhttp://en.wikipedia.org/wiki/Conventional_landing_gearhttp://en.wikipedia.org/wiki/Conventional_landing_gearhttp://en.wikipedia.org/wiki/Aerial_applicationhttp://en.wikipedia.org/wiki/Bush_planehttp://en.wikipedia.org/wiki/Bush_plane


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In automotive engineering, toe, also knownas tracking,[1]is the symmetric anglethat

each wheel makes with the longitudinal axisof the vehicle, as a function of staticgeometry, and kinematic and complianteffects. This can be contrasted with steer,which is the antisymmetric angle, i.e. bothwheels point to the left or right, in parallel(roughly).
http://en.wikipedia.org/wiki/Automotive_engineeringhttp://en.wikipedia.org/wiki/Toe_(automotive)http://en.wikipedia.org/wiki/Anglehttp://en.wikipedia.org/w/index.php?title=Steer_(automotive)&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Steer_(automotive)&action=edit&redlink=1http://en.wikipedia.org/wiki/Anglehttp://en.wikipedia.org/wiki/Toe_(automotive)http://en.wikipedia.org/wiki/Automotive_engineering


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Positive toe, or toe in, is the front of thewheel pointing in towards the centreline of

the vehicle. Negative toe, or toe out, is thefront of the wheel pointing away from thecentreline of the vehicle.[2]Toe can bemeasured in linear units, at the front of thetire, or as an angular deflection.
http://en.wikipedia.org/wiki/Toe_(automotive)http://en.wikipedia.org/wiki/Toe_(automotive)


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In a rear wheel drivecar, increased front toein provides greater straight-line stability at

the cost of some sluggishness of turningresponse. The wear on the tires is marginallyincreased as the tires are under slight side slipconditions. On front wheel drivecars, thesituation is more complex.
http://en.wikipedia.org/wiki/Rear_wheel_drivehttp://en.wikipedia.org/wiki/Front_wheel_drivehttp://en.wikipedia.org/wiki/Front_wheel_drivehttp://en.wikipedia.org/wiki/Rear_wheel_drive


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Toe is always adjustable in productionautomobiles, even though caster angleand

camber angleare often not adjustable.Maintenance of front end alignment, whichused to involve all three adjustments,currently involves only setting the toe; inmost cases, even for a car in which caster orcamber are adjustable, only the toe will needadjustment.
http://en.wikipedia.org/wiki/Caster_anglehttp://en.wikipedia.org/wiki/Camber_anglehttp://en.wikipedia.org/wiki/Wheel_alignmenthttp://en.wikipedia.org/wiki/Wheel_alignmenthttp://en.wikipedia.org/wiki/Camber_anglehttp://en.wikipedia.org/wiki/Caster_angle


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One related concept is that the proper toe forstraight line travel of a vehicle will not be

correct while turning, since the inside wheelmust travel around a smaller radius than theoutside wheel; to compensate for this, thesteering linkagetypically conforms more orless to Ackermann steering geometry,modified to suit the characteristics of theindividual vehicle.
http://en.wikipedia.org/wiki/Linkage_(mechanical)http://en.wikipedia.org/wiki/Ackermann_steering_geometryhttp://en.wikipedia.org/wiki/Ackermann_steering_geometryhttp://en.wikipedia.org/wiki/Linkage_(mechanical)


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When a wheel is set up to have some camberangle, the interaction between the tire and

road surface causes the wheel to tend towant to roll in a curve, as if it were part of aconical surface (camber thrust). Thistendency to turn increases the rollingresistanceas well as increasing tire wear.
http://en.wikipedia.org/wiki/Camber_anglehttp://en.wikipedia.org/wiki/Camber_anglehttp://en.wikipedia.org/wiki/Camber_thrusthttp://en.wikipedia.org/wiki/Rolling_resistancehttp://en.wikipedia.org/wiki/Rolling_resistancehttp://en.wikipedia.org/wiki/Rolling_resistancehttp://en.wikipedia.org/wiki/Rolling_resistancehttp://en.wikipedia.org/wiki/Camber_thrusthttp://en.wikipedia.org/wiki/Camber_anglehttp://en.wikipedia.org/wiki/Camber_angle


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A small degree of toe (toe-out for negativecamber, toe-in for positive camber) will

cancel this turning tendency, reducing wearand rolling resistance. On some competitionvehicles such as go-karts, especially wherepower is extremely limited and is highlyregulated by the rules of the sport, theseeffects can become very significant in termsof competitiveness and performance.
http://en.wikipedia.org/wiki/Go-karthttp://en.wikipedia.org/wiki/Go-karthttp://en.wikipedia.org/wiki/Go-karthttp://en.wikipedia.org/wiki/Go-kart


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Angulos de las ruedas.pptx