喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請(qǐng)放心下載，，有疑問(wèn)咨詢QQ:414951605或者1304139763 ======================== 喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請(qǐng)放心下載，，有疑問(wèn)咨詢QQ:414951605或者1304139763 ======================== GEAR?AND?SHAFT?INTRODUCTION Abstract:?The?important?position?of?the?wheel?gear?and?shaft?can't?falter?in?traditional?machine?and?modern?machines.The?wheel?gear?and?shafts?mainly?install?the?direction?that?delivers?the?dint?at?the?principal?axis?box.The?passing?to?process?to?make?them?can?is?divided?into?many?model?numbers,?useding?for?many?situations?respectively.So?we?must?be?the?multilayers?to?the?understanding?of?the?wheel?gear?and?shaft?in?many?ways?. ?Key?words:?Wheel?gear;Shaft In?the?force?analysis?of?spur?gears,?the?forces?are?assumed?to?act?in?a?single?plane.?We?shall?study?gears?in?which?the?forces?have?three?dimensions.?The?reason?for?this,?in?thecase?of?helical?gears,?is?that?the?teeth?are?not?parallel?to?the?axis?of?rotation.?And?in?the?case?of?bevel?gears,?the?rotational?axes?are?not?parallel?to?each?other.?There?are?also?other?reasons,?as?we?shall?learn. Helical?gears?are?used?to?transmit?motion?between?parallel?shafts.?The?helix?angle?is?the?same?on?each?gear,?but?one?gear?must?have?a?right-hand?helix?and?the?other?a?left-hand?helix.?The?shape?of?the?tooth?is?an?involute?helicoid.?If?a?piece?of?paper?cut?in?the?shape?of?a?parallelogram?is?wrapped?around?a?cylinder,?the?angular?edge?of?the?paper?becomes?a?helix.?If?we?unwind?this?paper,?each?point?on?the?angular?edge?generates?an?involute?curve.?The?surface?obtained?when?every?point?on?the?edge?generates?an?involute?is?called?an?involute?helicoid.? The?initial?contact?of?spur-gear?teeth?is?a?line?extending?all?the?way?across?the?face?of?the?tooth.?The?initial?contact?of?helical?gear?teeth?is?a?point,?which?changes?into?a?line?as?the?teeth?come?into?more?engagement.?In?spur?gears?the?line?of?contact?is?parallel?to?the?axis?of?the?rotation;?in?helical?gears,?the?line?is?diagonal?across?the?face?of?the?toot.?It?is?this?gradual?of?the?teeth?and?the?smooth?transfer?of?load?from?one?tooth?to?another,?which?give?helical?gears?the?ability?to?transmit?heavy?loads?at?high?speeds.?Helical?gears?subject?the?shaft?bearings?to?both?radial?and?thrust?loads.?When?the?thrust?loads?become?high?or?are?objectionable?for?other?reasons,?it?may?be?desirable?to?use?double?helical?gears.?A?double?helical?gear?(herringbone)?is?equivalent?to?two?helical?gears?of?opposite?hand,?mounted?side?by?side?on?the?same?shaft.?They?develop?opposite?thrust?reactions?and?thus?cancel?out?the?thrust?load.?When?two?or?more?single?helical?gears?are?mounted?on?the?same?shaft,?the?hand?of?the?gears?should?be?selected?so?as?to?produce?the?minimum?thrust?load.?Crossed-helical,?or?spiral,?gears?are?those?in?which?the?shaft?centerlines?are?neither?parallel?nor?intersecting.?The?teeth?of?crossed-helical?fears?have?point?contact?with?each?other,?which?changes?to?line?contact?as?the?gears?wear?in.?For?this?reason?they?will?carry?out?very?small?loads?and?are?mainly?for?instrumental?applications,?and?are?definitely?not?recommended?for?use?in?the?transmission?of?power.?There?is?on?difference?between?a?crossed?helical?gear?and?a?helical?gear?until?they?are?mounted?in?mesh?with?each?other.?They?are?manufactured?in?the?same?way.?A?pair?of?meshed?crossed?helical?gears?usually?have?the?same?hand;?that?is?,a?right-hand?driver?goes?with?a?right-hand?driven.?In?the?design?of?crossed-helical?gears,?the?minimum?sliding?velocity?is?obtained?when?the?helix?angle?are?equal.?However,?when?the?helix?angle?are?not?equal,?the?gear?with?the?larger?helix?angle?should?be?used?as?the?driver?if?both?gears?have?the?same?hand.?? Worm?gears?are?similar?to?crossed?helical?gears.?The?pinion?or?worm?has?a?small?number?of?teeth,?usually?one?to?four,?and?since?they?completely?wrap?around?the?pitch?cylinder?they?are?called?threads.?Its?mating?gear?is?called?a?worm?gear,?which?is?not?a?true?helical?gear.?A?worm?and?worm?gear?are?used?to?provide?a?high?angular-velocity?reduction?between?nonintersecting?shafts?which?are?usually?at?right?angle.?The?worm?gear?is?not?a?helical?gear?because?its?face?is?made?concave?to?fit?the?curvature?of?the?worm?in?order?to?provide?line?contact?instead?of?point?contact.?However,?a?disadvantage?of?worm?gearing?is?the?high?sliding?velocities?across?the?teeth,?the?same?as?with?crossed?helical?gears.? Worm?gearing?are?either?single?or?double?enveloping.?A?single-enveloping?gearing?is?one?in?which?the?gear?wraps?around?or?partially?encloses?the?worm..?A?gearing?in?which?each?element?partially?encloses?the?other?is,?of?course,?a?double-enveloping?worm?gearing.?The?important?difference?between?the?two?is?that?area?contact?exists?between?the?teeth?of?double-enveloping?gears?while?only?line?contact?between?thoseof?single-enveloping?gears.?The?worm?and?worm?gear?of?a?set?have?the?same?hand?of?helix?as?for?crossed?helical?gears,?but?the?helix?angles?are?usually?quite?different.?The?helix?angle?on?the?worm?is?generally?quite?large,?and?that?on?the?gear?very?small.?Because?of?this,?it?is?usual?to?specify?the?lead?angle?on?the?worm,?which?is?the?complement?of?the?worm?helix?angle,?and?the?helix?angle?on?the?gear;?the?two?angles?are?equal?for?a?90-deg.?Shaft?angle.? When?gears?are?to?be?used?to?transmit?motion?between?intersecting?shaft,?some?of?bevel?gear?is?required.?Although?bevel?gear?are?usually?made?for?a?shaft?angle?of?90?deg.?They?may?be?produced?for?almost?any?shaft?angle.?The?teeth?may?be?cast,?milled,?or?generated.?Only?the?generated?teeth?may?be?classed?as?accurate.?In?a?typical?bevel?gear?mounting,?one?of?the?gear?is?often?mounted?outboard?of?the?bearing.?This?means?that?shaft?deflection?can?be?more?pronounced?and?have?a?greater?effect?on?the?contact?of?teeth.?Another?difficulty,?which?occurs?in?predicting?the?stress?in?bevel-gear?teeth,?is?the?fact?the?teeth?are?tapered.?? Straight?bevel?gears?are?easy?to?design?and?simple?to?manufacture?and?give?very?good?results?in?service?if?they?are?mounted?accurately?and?positively.?As?in?the?case?of?squr?gears,?however,?they?become?noisy?at?higher?values?of?the?pitch-line?velocity.?In?these?cases?it?is?often?good?design?practice?to?go?to?the?spiral?bevel?gear,?which?is?the?bevel?counterpart?of?the?helical?gear.?As?in?the?case?of?helical?gears,?spiral?bevel?gears?give?a?much?smoother?tooth?action?than?straight?bevel?gears,?and?hence?are?useful?where?high?speed?are?encountered.?? It?is?frequently?desirable,?as?in?the?case?of?automotive?differential?applications,?to?have?gearing?similar?to?bevel?gears?but?with?the?shaft?offset.?Such?gears?are?called?hypoid?gears?because?their?pitch?surfaces?are?hyperboloids?of?revolution.?The?tooth?action?between?such?gears?is?a?combination?of?rolling?and?sliding?along?a?straight?line?and?has?much?in?common?with?that?of?worm?gears.? A?shaft?is?a?rotating?or?stationary?member,?usually?of?circular?cross?section,?having?mounted?upon?it?such?elementsas?gears,?pulleys,?flywheels,?cranks,?sprockets,?and?other?power-transmission?elements.?Shaft?may?be?subjected?to?bending,?tension,?compression,?or?torsional?loads,?acting?singly?or?in?combination?with?one?another. When?they?are?combined,?one?may?expect?to?find?both?static?and?fatigue?strength?to?be?important?design?considerations,?since?a?single?shaft?may?be?subjected?to?static?stresses,?completely?reversed,?and?repeated?stresses,?all?acting?at?the?same?time.?The?word?“shaft”?covers?numerous?variations,?such?as?axles?and?spindles.?Anaxle?is?a?shaft,?wither?stationary?or?rotating,?nor?subjected?to?torsion?load.?A?shirt?rotating?shaft?is?often?called?a?spindle.? When?either?the?lateral?or?the?torsional?deflection?of?a?shaft?must?be?held?to?close?limits,?the?shaft?must?be?sized?on?the?basis?of?deflection?before?analyzing?the?stresses.?The?reason?for?this?is?that,?if?the?shaft?is?made?stiff?enough?so?that?the?deflection?is?not?too?large,?it?is?probable?that?the?resulting?stresses?will?be?safe.?But?by?no?means?should?the?designer?assume?that?they?are?safe;?it?is?almost?always?necessary?to?calculate?them?so?that?he?knows?they?are?within?acceptable?limits.?Whenever?possible,?the?power-transmission?elements,?such?as?gears?or?pullets,?should?be?located?close?to?the?supporting?bearings,?This?reduces?the?bending?moment,?and?hence?the?deflection?and?bending?stress.? Although?the?von?Mises-Hencky-Goodman?method?is?difficult?to?use?in?design?of?shaft,?it?probably?comes?closest?to?predicting?actual?failure.?Thus?it?is?a?good?way?of?checking?a?shaft?that?has?already?been?designed?or?of?discovering?why?a?particular?shaft?has?failed?in?service.?Furthermore,?there?are?a?considerable?number?of?shaft-design?problems?in?which?the?dimension?are?pretty?well?limited?by?other?considerations,?such?as?rigidity,?and?it?is?only?necessary?for?the?designer?to?discover?something?about?the?fillet?sizes,?heat-treatment,?and?surface?finish?and?whether?or?not?shot?peening?is?necessary?in?order?to?achieve?the?required?life?and?reliability.? Because?of?the?similarity?of?their?functions,?clutches?and?brakes?are?treated?together.?In?a?simplified?dynamic?representation?of?a?friction?clutch,?or?brake,?two?in?ertias?I1?and?I2?traveling?at?the?respective?angular?velocities?W1?and?W2,?one?of?which?may?be?zero?in?the?case?of?brake,?are?to?be?brought?to?the?same?speed?by?engaging?the?clutch?or?brake.?Slippage?occurs?because?the?two?elements?are?running?at?different?speeds?and?energy?is?dissipated?during?actuation,?resulting?in?atemperature?rise.?In?analyzing?the?performance?of?these?devices?we?shall?be?interested?in?the?actuating?force,?the?torque?transmitted,?the?energy?loss?and?the?temperature?rise.?The?torque?transmitted?is?related?to?the?actuating?force,?the?coefficient?of?friction,?and?the?geometry?of?the?clutch?or?brake.?This?is?problem?in?static,?which?will?have?to?be?studied?separately?for?eath?geometric?configuration.?However,?temperature?rise?is?related?to?energy?loss?and?can?be?studied?without?regard?to?the?type?of?brake?or?clutch?because?the?geometry?of?interest?is?the?heat-dissipating?surfaces.?The?various?types?of?clutches?and?brakes?may?be?classified?as?fllows:?? 1.?Rim?type?with?internally?expanding?shoes?2.?Rim?type?with?externally?contracting?shoes?3.?Band?type? 4.?Disk?or?axial?type?5.?Cone?type? 6.?Miscellaneous?type? The?analysis?of?all?type?of?friction?clutches?and?brakes?use?the?same?general?procedure.?The?following?step?are?necessary:?? 1.?Assume?or?determine?the?distribution?of?pressure?on?the?frictional?surfaces.?2.?Find?a?relation?between?the?maximum?pressure?and?the?pressure?at?any?point?3.?Apply?the?condition?of?statical?equilibrium?to?find?(a)?the?actuating?force,?(b)?the?torque,?and?(c)?the?support?reactions.? Miscellaneous?clutches?include?several?types,?such?as?the?positive-contact?clutches,?overload-release?clutches,?overrunning?clutches,?magnetic?fluid?clutches,?and?others.? A?positive-contact?clutch?consists?of?a?shift?lever?and?two?jaws.?The?greatest?differences?between?the?various?types?of?positive?clutches?are?concerned?with?the?design?of?the?jaws.?To?provide?a?longer?period?of?time?for?shift?action?during?engagement,?the?jaws?may?be?ratchet-shaped,?or?gear-tooth-shaped.?Sometimes?a?great?many?teeth?or?jaws?are?used,?and?they?may?be?cut?either?circumferentially,?so?that?they?engage?by?cylindrical?mating,?or?on?the?faces?of?the?mating?elements.?Although?positive?clutches?are?not?used?to?the?extent?of?the?frictional-contact?type,?they?do?have?important?applications?where?synchronous?operation?is?required.?Devices?such?as?linear?drives?or?motor-operated?screw?drivers?must?run?to?definite?limit?and?then?come?to?a?stop.?An?overload-release?type?of?clutch?is?required?for?these?applications.?These?clutches?are?usually?spring-loaded?so?as?to?release?at?a?predetermined?toque.?The?clicking?sound?which?is?heard?when?the?overload?point?is?reached?is?considered?to?be?a?desirable?signal.? An?overrunning?clutch?or?coupling?permits?the?driven?member?of?a?machine?to?“freewheel”?or?“overrun”?because?the?driver?is?stopped?or?because?another?source?of?power?increase?the?speed?of?the?driven.?This??type?of?clutch?usually?uses?rollers?or?balls?mounted?between?an?outer?sleeve?and?an?inner?member?having?flats?machined?around?the?periphery.?Driving?action?is?obtained?by?wedging?the?rollers?between?the?sleeve?and?the?flats.?The?clutch?is?therefore?equivalent?to?a?pawl?and?ratchet?with?an?infinite?number?of?teeth.??Magnetic?fluid?clutch?or?brake?is?a?relatively?new?development?which?has?two?parallel?magnetic?plates.?Between?these?plates?is?a?lubricated?magnetic?powder?mixture.?An?electromagnetic?coil?is?inserted?somewhere?in?the?magnetic?circuit.?By?varying?the?excitation?to?this?coil,?the?shearing?strength?of?the?magnetic?fluid?mixture?may?be?accurately?controlled.?Thus?any?condition?from?a?full?slip?to?a?frozen?lockup?may?be?obtained.? Introduciton?of?Machining? Have?a?shape?as?a?processing?method,?all?machining?process?for?the?production?of?the?most?commonly?used?and?most?important?method.?Machining?process?is?a?process?generated?shape,?in?this?process,?Drivers?device?on?the?workpiece?material?to?be?in?the?form?of?chip?removal.?Although?in?some?occasions,?the?workpiece?under?no?circumstances,?the?use?of?mobile?equipment?to?the?processing,?However,?the?majorityof?the?machining?is?not?only?supporting?the?workpiece?also?supporting?tools?and?equipment?to?complete.? Machining?know?the?process?has?two?aspects.?Small?group?of?low-cost?production.?For?casting,?forging?and?machining?pressure,?every?production?of?a?specific?shape?of?the?workpiece,?even?a?spare?parts,?almost?have?to?spend?the?high?cost?of?processing.?Welding?to?rely?on?the?shape?of?the?structure,?to?a?large?extent,?depend?on?effective?in?the?form?of?raw?materials.?In?general,?through?the?use?of?expensive?equipment?and?without?special?processing?conditions,?can?be?almost?any?type?of?raw?materials,?mechanical?processing?to?convert?the?raw?materials?processed?into?the?arbitrary?shape?of?the?structure,?as?long?as?the?external?dimensions?large?enough,?it?is?possible.?Because?of?a?production?of?spare?parts,?even?when?the?parts?and?structure?of?the?production?batch?sizes?are?suitable?for?the?original?casting,?Forging?or?pressure?processing?to?produce,?but?usually?prefer?machining.? Strict?precision?and?good?surface?finish,?Machining?the?second?purpose?is?the?establishment?of?the?high?precision?and?surface?finish?possible?on?the?basis?of.?Many?parts,?if?any?other?means?of?production?belonging?to?the?large-scale?production,?Well?Machining?is?a?low-tolerance?and?can?meet?the?requirements?of?small?batch?production.?Besides,?many?parts?on?the?production?and?processing?of?coarse?process?to?improve?its?general?shape?of?the?surface.?It?is?only?necessary?precision?and?choose?only?the?surface?machining.?For?instance,?thread,?in?addition?to?mechanical?processing,?almost?no?other?processing?method?for?processing.?Another?example?is?the?blacksmith?pieces?keyhole?processing,?as?well?as?training?to?be?conducted?immediately?after?the?mechanical?completion?of?the?processing.?Primary?Cutting?Parameters? Cutting?the?work?piece?and?tool?based?on?the?basic?relationship?between?the?following?four?elements?to?fully?describe?:?the?tool?geometry,?cutting?speed,?feed?rate,?depth?and?penetration?of?a?cutting?tool.? Cutting?Tools?must?be?of?a?suitable?material?to?manufacture,?it?must?be?strong,?tough,?hard?and?wear-resistant.?Tool?geometry?--?to?the?tip?plane?and?cutter?angle?characteristics?--?for?each?cutting?process?must?be?correct.? Cutting?speed?is?the?cutting?edge?of?work?piece?surface?rate,?it?is?inches?per?minute?to?show.?In?order?to?effectively?processing,?and?cutting?speed?must?adapt?to?the?level?of?specific?parts?--?with?knives.?Generally,?the?more?hard?work?piece?material,?the?lower?the?rate.? Progressive?Tool?to?speed?is? cut?into?the?work?piece?speed.?If?the?work?piece?or?tool?for?rotating?movement,?feed?rate?per?round?over?the?number?of?inches?to?the?measurement.?When?the?work?piece?or?tool?for?reciprocating?movement?and?feed?rate?on?each?trip?through?the?measurement?of?inches.?Generally,?in?other?conditions,?feed?rate?and?cutting?speed?is?inversely?proportional?to。?? Depth?of?penetration?of?a?cutting?tool?--?to?inches?dollars?--?is?the?tool?to?the?work?piece?distance.?Rotary?cutting?it?to?the?chip?or?equal?to?the?width?of?the?linear?cutting?chip?thickness.?Rough?than?finishing,?deeper?penetration?of?a?cutting?tool?depth.? Wears?of?Cutting?Tool? We?already?have?been?processed?and?the?rattle?of?the?countless?cracks?edge?tool,?we?learn?that?tool?wear?are?basically?three?forms?:?flank?wear,?the?former?flank?wear?and?V-Notch?wear.?Flank?wear?occurred?in?both?the?main?blade?occurred?vice?blade.?On?the?main?blade,?shoulder?removed?because?most?metal?chip?mandate,?which?resulted?in?an?increase?cutting?force?and?cutting?temperature?increase,?If?not?allowed?to?check,?That?could?lead?to?the?work?piece?and?the?tool?vibration?and?provide?for?efficient?cutting?conditions?may?no?longer?exist.?Vice-bladed?on,?it?is?determined?work?piece?dimensions?and?surface?finish.?Flank?wear?size?of?the?possible?failure?of?the?product?and?surface?finish?are?also?inferior.?In?most?actual?cutting?conditions,?as?the?principal?in?the?former?first?deputy?flank?before?flank?wear,?wear?arrival?enough,?Tool?will?be?effective,?the?results?are?made?unqualified?parts.?As?Tool?stress?on?the?surface?uneven,?chip?and?flank?before?sliding?contact?zone?between?stress,?in?sliding?contact?the?start?of?the?largest,?and?in?contact?with?the?tail?of?zero,?so?abrasive?wear?in?the?region?occurred.?This?is?because?the?card?cutting?edge?than?the?nearby?settlements?near?the?more?serious?wear,?and?bladed?chip?due?to?the?vicinity?of?the?former?flank?and?lost?contact?wear?lighter.?This?results the?tool,?workpiece?and?chip.?A?typical?set?of?isotherms?is?shown?in?figure?where?it?can?be?seen?that,?as?could?be?expected,?there?is?a?very?large?temperature?gradient?throughout?the?width?of?the?chip?as?the?workpiece?material?is?sheared?in?primary?deformation?and?there?is?a?further?large?temperature?in?the?chip?adjacent?to?the?face?as?the?chip?is?sheared?in?secondary?deformation.?This?leads?to?a?maximum?cutting?temperature?a?short?distance?up?the?face?from?the?cutting?edge?and?a?small?distance?into?the?chip.? Since?virtually?all?the?work?done?in?metal?cutting?is?converted?into?heat,?it?could?be?expected?that?factors?which?increase?the?power?consumed?per?unit?volume?of?metal?removed?will?increase?the?cutting?temperature.?Thus?an?increase?in?the?rake?angle,?all?other?parameters?remaining?constant,?will?reduce?the?power?per?unit?volume?of?metal?removed?and?cutting?temperatures?will?reduce.?When?considering?increase?in?undeformed?chip?thickness?and?cutting?speed?the?situation?is?more?comples.?An?increase?in?undeformed?chip?thickness?and?cutting?speed?the?situation?is?more?complex.?An?increase?in?undeformed?chip?thickness?tends?to?be?a?scale?effect?where?the?amounts?of?heat?which?pass?to?the?workpiece,?the?tool?and?chip?remain?in?fixed?proportions?and?the?changes?in?cutting?temperature?tend?to?be?small.?Increase?in?cutting?speed,?however,?reduce?the?amount?of?heat?which?passes?into?the?workpiece?and?this?increase?the?temperature?rise?of?the?chip?in?primary?deformation.?Further,?the?secondary?deformation?zone?tends?to?be?smaller?and?this?has?the?effect?of?increasing?the?temperatures?in?this?zone.?Other?changes?in?cutting?parameters?have?virtually?no?effect?on?the?power?consumed?per?unit?volume?of?metal?removed?and?consequently?have?virtually?no?effect?on?the?power?consumed?per?unit?volume?of?metal?removed?and?consequently?have?virtually?no?effect?on?the?cutting?temperatures.?Since?it?has?been?shown?that?even?small?changes?in?cutting?temperature?have?a?significant?effect?on?tool?wear?rate,?it?is?appropriate?to?indicate?how?cutting?temperatures?can?be?assessed?from?cutting?data.?? The?most?direct?and?accurate?method?for?measuring?temperatures?in?high-speed-steel?cutting?tools?is?that?of?Wright&Trent?which?also?yields?detailed?information?on?temperature?distributions?in?high-speed-steel?tools?which?relates?microstructural?changes?