001 Machine Components Power Transmission Elements，14页双PPT，参考文献价值英文文献资料

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1、MachineComponents:PowerTransmissionElementsME72EngineeringDesignLaboratoryPowerTransmissionDesignIssues•Powersource(motor,engine,etc.)•Powerrequired(P=torque´velocity)•ContinuousorIntermittentMotion•Operatingconditions(start,loadduration)•Magnitudeofspeed(inputo

2、routput)•Speedmodification(outputtoinput,constantorvariable,linearorrotary)1ConstantSpeedMechanicalTransmissionElements•Gears•Frictionwheels•PowerScrews•BeltsandChains•WireRope•Couplings•ClutchesandBrakes2RelativeShaftPositionRelativeSize3GearDesignIssues•Typeso

3、fGears:spur,helical,herringbone,internal,rack,bevel,andworm•AngularVelocityRatio(gearratio)•PowerRequirements(speedandtorque)•GearToothLoads•GearToothStresses4GearTerminology•PitchCircle(radiusordiameter)•CircularPitch•NumberofTeeth•PressureAngle•FaceWidth5SpurG

4、ears:ForceAnalysis•Wistheresultantforce•WtandWraretangentialandradialcomponents•disthepitchdiameter•fisthepressureangle•tistheappliedtorque2tWt=dWtW=cosfWWrt=tanfHelicalGears:ForceAnalysis•Wt,WrandWaaretangentialandradialandaxialcomponents•fnisthenormalpressurea

5、ngle•ftisthetangentpressureangle•yisthehelixangle2tWt=dWWrn==sinffWttantWWtn=cosfycosWWant==cosfysinWtany6BevelGears:ForceAnalysis•Wt,WrandWaaretangentialandradialandaxialcomponents•fisthepressureangle•gisthebevelangle•ravistheaveragepitchradiustWt=ravWWrt=tanco

6、sfgWWat=tansinfgWormGears:ForceAnalysis•Wt,WrandWaaretangentialandradialandaxialcomponents•fnisthenormalpressureangle•listhewormleadangle•dwormisthepitchdiameteroftheworm2tWt=dwormxWWW==tncosflsinyWWW==rnsinfzWWW==ancosflcos7StressesinGears:LewisFormulatMcWlt()2

7、6Wltsb==bt3=2Iwbt12w2tl=4x3W3WpWpttdtds===b2bx2bpxbYwwdw2pxdY==LewisFormFactor3StressesinGears:AGMAFormula•s=bendingstress•Assumptionsb•Wt=tangentialforce–Contactratiois1-2•p=pitchdiameterd–Nointerferenceor•bw=facewidthundercutting•J=geometryfactor–Nopointedteet

8、h•Ka=applicationfactor•Km=loaddistributionfactor–Nonzerobacklash•K=sizefactors–Standardrootfillets•Kv=dynamicfactor–FrictionneglectedWptdKKKamssb=bJwKv8PowerScrews•Co