Transcription

Machines and Mechanisms: AppliedKinematic Analysis, 4/eChapter 1

Chap 1 IntroductionMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka2 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.1 INTRODUCTION Determine appropriate movementof the wipers View rangeTandem or oppositeWipe angleLocation of pivotsTiming of wipersWiping velocityThe force acting on the machineMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka3 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.2 MACHINES AND MECHANISMS Machine Devices used to alter,transmit, and direct forcesto accomplish a specificobjectiveMechanism Mechanical portion of amachine that has thefunction of transferringmotion and forces from apower source to an outputMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka4 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.3 KINEMATICSMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka5 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

DynamicsMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka6 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Kinematics Kinematics Kinematic analysis Determine Position, displacement, rotation, speed, velocity, accelerationProvide Geometry dimensions of the mechanism Operation rangeDynamic analysis Deal with the way things movePower capacity, stability, member loadPlanar mechanism – motion in 2D spaceMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka7 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.4 MECHANISM TERMINOLOGYMechanism Synthesis is the process of developing mechanism to satisfy a set of performance requirementsfor the machine.Analysis ensures that the mechanism will exhibit motion to accomplish the requirements . LinkageFrameLinks– rigid bodyJointPrimary joint (full joint) Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka8Revolute joint (pin or hinge joint)– purerotationSliding joint (piston or prism joint)– linearsliding 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Higher-order joint (half joint) Simple link A rigid body contains only two jointsCrankRockerComplex link Allow rotation and slidingCam jointGear connectionA rigid body contains more than twojointsRocker armBellcrankPoint of interestActuator A power source linkMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka9 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.5 Kinematic DiagramMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka10 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Kinematic DiagramMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka11 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka12 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka13 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka14 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.7 MOBILITY1.7.1 Gruebler’s EquationMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka15 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Constrained mechanism Locked mechanism one degree of freedomZero or negative degrees of freedomUnconstrained mechanism More than one degree of freedomMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka16 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka17 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka18 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka19 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Actuators and Drivers Electric motors (AC)Electric motors (DC)EnginesServomotorsAir or hydraulic motorsHydraulic or pneumatic cylindersScrew actuatorsManual1.7.2 Actuators and DriversMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka20 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka21 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.8 COMMONLY USED LINKS AND JOINTS1.8.1 Eccentric Crank1.8.2 Pin-in-a-Slot Joint1.8.3 Screw JointMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka22 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka23 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.9 SPECLAL CASES OF THE MOBILITY EQUATION1.9.1 Coincident Joints1.9.2 One degree of freedom actually if pivoted links are the same sizeMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka24 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka25 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.10 THE FOUR-BAR MECHANISMMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka26 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka27 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.10.1 Degree-of-Freedoms : short linkl : long linkp , q : intermediate linkMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka28 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka29 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.11 SLIDER-CRANK MECHANISMMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka30 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.12 SPECIAL PURPOSE MECHANISMS1.12.1 Straight-Line MechanismsMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka31 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.12.2 Parallelogram MechanismsMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka32 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.12.3 Quick-Return MechanismsMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka33 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

1.12.4 Scotch Yoke MechanismMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka34 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis,4/eChapter 4 Displacement Analysis

4.2 POSITION4.2.1 Position of a Point4.3 DISPLACEMENT4.3.1 Linear Displacement4.3.2 Angular DisplacementMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka36 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

4.4 DISPLACEMENT ANALYSIS Locate the positions of alllinks as driver link isdisplacedConfiguration Positions of all the linksOne degree of freedom Moving one link willprecisely position allother linksMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka37 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

4.5 DISPLACEMENT:GRAPHICAL ANALYSIS4.5.1 Displacement of a Single Driving Link4.5.2 Displacement of the Remaining Slave LinksMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka38 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

4.5.2 Displacement of the Remaining Slave LinksMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka39 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka40 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka41 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

4.1 Vector Analysis of DisplacementY1Yr4r2r3r3r5X1r1r4X(1) r 1 r 2 r 3 r 4 0 r1s 1 r2 c 2 r3c 3 5.3 r c r s r s 3.2 0 1 1 2 2 3 3 r1 3, 1 30, r2 4.9, r3 3.32 equations for 2 unknows 2 , 3(2) r 3 r 4 r 5 0 r3c 3 r4 c 4 x1 r s r s 0 3 3 4 4 0.8 r1 10.12 equations for 2 unknows 4 and x1Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka42 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka43 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Yr1r2r4Xr3r 1 r 2 r 3 r 4 0 1.6 3c 2 r3c 3 2.3 1.5 3s r s 0 0 2 3 3 r3 (3.92 1.22 )1/2solve for 2 and 3Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka44 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Analysis of Mechanism PositionMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka45 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Yr1r2r3Xr 1 r 2 r 3 0 50c 1 40c 2 d1 50 s 40s 0 0 1 2 1 240 , solve for 2 and d1when rotate 15 , 1 255 50c 1 40c 2 d 2 50 s 40s 0 0 1 2 solve for 2 and d 2 d d1 d 2Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka46 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka47 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

4.6.1 Closed-Form Position Analysis Equations for an In-LineSlider-CrankMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka48 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

4.6.2 Closed-Form Position Analysis Equations for an OffsetSlider-CrankMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka49 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka50 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Yr2r3r1r4Xr 1 r 2 r 3 r 4 0 12c 1 20c 2 15c 3 25 12s 20s 15s 0 0 1 2 3 1 90 , eqs. solve for 2 and 3 1 60 , eqs. solve for 2 and 3Calculate the difference of 2 in and Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka51 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka52 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Yr1Xr3r2r 1 r 2 r 3 0 0.5c 1 1.75c 2 1 0.5s 1.75s y 0 1 2 for 1 2 , solve for 1 and ymax for 1 2 , solve for 1 and yminMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka53 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

4.7 LIMITING POSITIONS:Machines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka54 2012, 2005, 2002, 1999 Pearson Higher Education,Upper Saddle River, NJ 07458. All Rights Reserved.

Yr1Xr2r4r3r 1 r 2 r 3 r 4 0for 1 2 , solve for 1 and 3 )max for 1 2 , solve for 1 and 3 )minMachines and Mechanisms: Applied Kinematic Analysis, 4/eDavid Myszka