SAE J 1451-1985 A Dictionary of Terms for the Dynamics and Handling of Single Track Vehicles (Motorcycles Mopeds and Bicycles).pdf

1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro

2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.Copyright 2007 SAE InternationalAll rights reserved. No part of this publication may be

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4、776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSURFACEVEHICLEINFORMATIONREPORTJ1451REAF.AUG2007Issued 1985-02Reaffirmed 2007-08Superseding J1451 JAN2000A Dictionary of Terms for the Dynamics and Handling of Single Track Vehicles(Motorcycles, Mopeds, and Bicycles)1. ScopeThis

5、dictionary of terms was prepared for use by those with a need to describe and understand thedynamics and handling of two-wheeled, single track vehicles. It is intended to span the gap between vehicledynamics specialists and those with a more general interest.This report is pertinent to such areas as

6、 vehicle design and development, the description of two-wheelerproperties, rider training and education, and the preparation of standards and regulations.This report was prepared by the SAE Motorcycle Committee, which solicits suggestions for improvements andadditions to be considered in future revi

7、sions. Comments should be directed to SAE Headquarters.1.1 RationaleThis document has been reaffirmed to comply with the SAE 5-Year Review policy.2. References2.1 Applicable PublicationThe following publication forms a part of the specification to the extent specifiedherein. Unless otherwise indicat

8、ed the lastest revision of SAE publications shall apply.2.1.1 SAE PUBLICATIONAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel:877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.SAE J670eVehicle Dynamics Terminology3. Definitions3.1 AccelerationT

9、he time rate of change of velocity.3.2 Aerodynamic Drag ForceA force opposite to the direction of travel due to aerodynamic resistance,measured in the nominal plane of symmetry of the vehicle. For some engineering purposes, it can be defined,alternatively, parallel to the relative wind vector.3.3 Al

10、igning Moment (on tire)Torque from the roadway, acting on a tire, which tends to keep the wheel planeparallel to the vehicle velocity vector (at the tire contact point). See also SAE J670e.3.4 Angular VelocityRotational velocity about an axis.SAE J1451 Reaffirmed AUG2007-2-3.5 Antilock Brake SystemA

11、 braking system that automatically controls the slip ratio of one or more wheels ofthe vehicle during braking.3.6 Antiskid Brake SystemSee antilock brake system.3.7 Axis SystemA coordinate system fixed in the vehicle, a component body, or the roadway, for purposes ofdefining positions and motions.3.

12、8 AxleThe shaft which comprises the spin axis of a wheel.3.9 Bank AngleSee roll angle.3.10 Bounce MotionTranslational motion of the vehicle in a direction parallel to its nominal plane of symmetry(i.e., relative to body fixed axes). Vertical translation if the vehicle is upright. See also SAE J670e.

13、3.11 Brake FadeReduction in the braking torque on a wheel for a given level of rider brake control force; causedby thermal or water factors, for example.3.12 BrakingThe process of decelerating the vehicle by applying the brakes.3.13 Camber AngleThe roll or tilt angle of the plane of a wheel, measure

14、d relative to vertical. See alsoSAE J670e.3.14 Camber ThrustThe side force generated by a tire due to camber angle.3.15 CapsizeTendency of the vehicle to roll from an upright position.3.16 Capsize ModeA usually low frequency dynamic characteristic of the vehicle which exists in the absence ofrider c

15、ontrol. If stable, the vehicle will gradually return to an upright position; and if unstable, the vehicle willgradually roll and turn from its original direction of travel.3.17 Caster AngleSee rake angle.3.18 Center of GravityIf the vehicle is supported at this point, it will not rotate due to the f

16、orce of gravity. Seemass center.3.19 ChopperA motorcycle style and design, usually the result of aftermarket modification, which typicallyfeatures lengthened forks, increased rake angle, modified suspension, small front tire and large rear tire, and alowered rider seating position. The brakes and dr

17、ive train may be modified also.3.20 ComplianceStructural deflection, bending, or rotation.3.21 Cornering LimitThe maximum vehicle lateral acceleration at a given speed; usually determined by roadclearance of the vehicle structure (foot pegs, muffler, etc.) or by tire/roadway adhesion.3.22 Cornering

18、StiffnessThe amount of side force generated by a tire per unit slip angle. Quantified as a tireside force coefficient. See also SAE J670e.3.23 Cornering WeaveA combined pitching and yawing motion which can occur in a steady-state turn, undercertain adverse conditions. See also pitch-weave coupling.3

19、.24 Counter SteerThe process whereby the rider applies a steer torque in the direction opposite to that whichthe vehicle is turning, or is intended to turn.SAE J1451 Reaffirmed AUG2007-3-3.25 Coupled MotionsCoupling occurs when different motions (i.e., about different axes) have similarfrequencies,

20、and their oscillatory behavior has a definite phase relation.3.26 Course AngleSee path angle.3.27 DamperA device which produces a reactive force or torque as a function of translational or rotationalvelocity, respectively. See shock absorber. See also friction damper.3.28 Damper RateThe amount of fo

21、rce or torque produced by a damper as a function of velocity.3.29 DampingThe process of diminishing amplitude progressively.3.30 Damping RatioA measure of the amount of damping for oscillatory systems. See also SAE J670e.3.31 Degree-of-FreedomA characteristic motion of the vehicle, or a relative mot

22、ion between component bodies.Measured about or along an axis. One or more degrees-of-freedom are associated with each mode of motion.See also SAE J670e.3.32 DestabilizeTo reduce the stability or damping, e.g., of a characteristic motion or dynamic mode.3.33 DivergenceA motion with progressively incr

23、easing amplitude, an instability.3.34 Down TubesThe lower frame members; typically extending from the head, down and under the motor andback to the swing arm pivot.3.35 Drive TrainThe mechanism between the motor and a driven wheel.3.36 DrivingThe process of accelerating the vehicle or maintaining fo

24、rward velocity.3.37 DynamicsThe branch of mechanics which treats the motion of bodies (kinematics) and the action of forceswhich produce or change the motion (kinetics).3.38 EigenvalueA numerical value, derived from mathematical modeling and equations of motion, whichdescribes the frequency, amplitu

25、de, and damping properties of a mode of motion.3.39 End-OverAn extreme forward pitching motion; typically resulting in the rider and the rear frame assemblygoing over the front wheel in the direction of travel. Also called an endo or a reverse wheelie.3.40 EnduroA motorcycle sporting event or race r

26、un off-road and cross country from one point to another, usuallylasting hours or days, and emphasizing timing, speed, and reliability. Also a motorcycle intended to compete insuch an event.3.41 Equations of MotionA set of mathematical relationships which describe and quantify the dynamics of thevehi

27、cle.3.42 EquilibriumA state of balance among the forces acting on the vehicle, wherein the resulting motions haveachieved steady-state values.3.43 FadeSee brake fade.3.44 FairingA windscreen device on the front of the vehicle attached to either the fork assembly or rear frameassembly.SAE J1451 Reaff

28、irmed AUG2007-4-3.45 Feedback ControlThe process of comparing output motions with desired (input) motions in order toregulate against disturbances and follow a prescribed path. The rider accomplishes this by making controlactions in response to perceived cues, thereby establishing feedback loops. Se

29、e also rider control.3.46 ForkThe mechanism between the steering head and the front wheel axle; including the triple clamps, forkslider tubes, and shock absorbers. The fairing, lights, fender, front wheel, handlebars, etc., are excluded.3.47 Fork AssemblyThe connected set of components which rotates

30、 as a single body about the steer axis. Itincludes the fork, fairing, lights, fender, front wheel and tire, front brake, handlebars, etc. The fork assemblyplus the rear frame assembly constitute the vehicle.3.48 Fork ClampSee triple clamp.3.49 Fork Hinge LineSee steer axis.3.50 Fork OffsetThe perpen

31、dicular distance from the steer axis to the front axle.3.51 Fork Rake AngleSee rake angle.3.52 Fork Steer AngleSee steer angle.3.53 Fork TubeThe upper fork component that connects to the triple clamp above, and the slider tube below.3.54 FrameThe structural part of the rear frame assembly. Attached

32、to it, typically, are the fork assembly, themotor and transmission, the rear swing arm and suspension, the riders seat, and numerous other mechanicalcomponents.3.55 Frame AssemblySee rear frame assembly.3.56 Frame FlexibilityStructural deflection and bending of the frame.3.57 Frame HeadSee steering

33、head.3.58 Frame Rake AngleSee rake angle.3.59 Free ControlThe situation where the rider provides no control input to the vehicle; typically, by removing his/her hands from the handlebar and making no body motions.3.60 FrequencyFor periodic or oscillatory motion, a measure of the cycles completed per

34、 unit time. See alsoSAE J670e.3.61 Friction DamperA device wherein the reacting force or torque is roughly constant with velocity, and resultsfrom Coulomb friction.3.62 Front AssemblySee fork assembly.3.63 Front ForkSee fork.3.64 GainThe numerical ratio between the amplitude of the output and input

35、of a component under specifiedconditions.3.65 GroovingSee pavement grooving.SAE J1451 Reaffirmed AUG2007-5-3.66 Gross Axle Weight Rating (GAWR)The value specified by the manufacturer as the load carrying capacityof a single axle system, as measured at the tire-roadway interface.3.67 Gross Vehicle We

36、ight Rating (GVWR)The value specified by the manufacturer as the loaded weight.3.68 Gyroscopic MomentThe reactive torque on the spin axis of a momentum wheel, resulting from precession.3.69 HandlingThe response properties of a vehicle as perceived and experienced by the rider acting as acontroller.3

37、.70 HeadSee steering head.3.71 Heading AngleThe horizontal angle between a reference axis fixed in the vehicle and a reference axis fixedin the roadway, giving a measure of vehicle yaw rotation or directional orientation relative to the roadway. Seealso SAE J670e.3.72 High-SideA vehicle upset involv

38、ing an extreme rolling and capsizing motion, where the upper part of thevehicle rolls towards the direction of travel.3.73 High Speed WeaveSee weave mode.3.74 Hinge LineSee steer axis.3.75 Inclination AngleSee camber angle.3.76 InertiaThe resistance offered by a body to a change in its state of moti

39、on. See mass and moment of inertia.3.77 InstabilityThe condition of being unstable, a tendency for the amplitude of motion to increase progressivelywithout bound. See divergence.3.78 KinematicsThe translational and rotational motions of the vehicle and its component bodies.3.79 LashSee snatch.3.80 L

40、ateralTo the side. See lateral-directional.3.81 Lateral AccelerationThe side acceleration of the vehicle, in a horizontal plane and perpendicular to alongitudinal axis in the plane of symmetry. See also SAE J670e.3.82 Lateral-DirectionalHaving to do with overall vehicle motions and forces to the sid

41、e of the vehicle. Suchmotions include roll, yaw or heading, and side-to-side translation. They include the response to rider steer andside-to-side body movement inputs. Note: The remaining overall vehicle motions are mainly longitudinal.3.83 Lateral ForceSee side force.3.84 LeanSee rider lean or (ve

42、hicle) roll angle.3.85 Lift ForceAn upward force, due to aerodynamic flow, lying in the vehicles nominal plane of symmetry. Avertical force component if the vehicle is upright.3.86 Linear BehaviorMotions when the vehicle response has the following (linear) properties: Superpositionholds, the proport

43、ionality between input and output is independent of the input amplitude, the output cannotcontain components at frequencies not present in the input, and the question of stability is unaffected by thenature of the input function and the initial conditions.SAE J1451 Reaffirmed AUG2007-6-3.87 Link Rat

44、ioThe ratio of: (1) the force at the reference point in the suspension to (2) the normal force appliedat the tire contact point when the wheel is perpendicular to the roadway.3.88 Load TransferRefers to a redistribution in the normal load between the front and rear tires, usually due tobraking or dr

45、iveline torques. Aerodynamic forces, and rider and passenger position changes can be factors, aswell. See also SAE J670e.3.89 Longitudinal Fore and AftIn general, having to do with overall vehicle motions and forces in the nominalplane of symmetry. These motions include pitch, bounce, and forward tr

46、anslation. They include the responseto rider throttle, brake, and fore and aft body movement inputs. Note: The remaining overall vehicle motionsare mainly lateral-directional.3.90 Longitudinal AccelerationThe fore and aft acceleration of the vehicle, in a horizontal plane and along alongitudinal axi

47、s in the plane of symmetry. See also SAE J670e.3.91 Longitudinal Slip VelocityThe difference between the rotational velocity of a driven or braked wheel, andthe rotational velocity of a free rolling wheel. See slip ratio.3.92 Low-SideA vehicle upset involving an extreme rolling and capsizing motion,

48、 where the upper part of thevehicle rolls away from the direction of travel, e.g., a lay down.3.93 MassA quantity of matter. In the earths gravitational field, 1 kg of mass weighs about 9.8 N (in the metric, SIsystem), and 1 slug of mass weighs about 32 lb (in the traditional U.S. system).3.94 Mass

49、CenterThe point in a free rigid body where, if a force is applied, only translational acceleration results.Conversely, if a force is applied to a free body at any point other than the mass center, a rotational accelerationwill occur, also, due to the resulting moment about the mass center.3.95 Mechanical TrailThe perpendicular distance from the steer axis to the front tire contact point. It issometimes measured horizontally, also, from the point where the steer axis intersects the road