汽车差速器中英文对照外文翻译文献.

汽车差速器中英文对照外文翻译文献 FailureanalysisofanautomobiledifferentialpinionshaftAbstractDifferentialisusedtodecreasethespeedandtoprovidemomentincreasefortransmittingthecomingfromtheenginetothewheelsbyturning itaccording tothesuitable angleinvehicles andtoprovide thatinnerandouterturndifferently. Piniongearandshaftattheentrancearemanufactured asasinglepartwhereastheyareindifferentformsaccordingtoautomobileMirrorgearwhichwillworkwiththisgearshouldbecomefamiliar beforetheassembly. Incaseofanybreakdown, theyshouldbechangedasapair.Generally, inthesesystemsthereareweardamagesingears.Thegearinspected inthisstudyhasdamageasaformofshaftfracture.Inthisstudy,failureanalysisofthedifferentialpinionshaftiscarriedout.Mechanicalcharacteristics ofthematerialareobtainedfirst.Then,themicrostructure andchemicalcompositionsaredetermined.Somefractographicstudiesare2020ElsevierLtd.Allrightsreserved.Keywords: Differential;Fracture;Powertransfer;Pinionshaft1.IntroductionThefinal-drivegearsbedirectlyorindirectly drivenfromtheoutputgearingofthegearbox.Directlydrivenfinaldrivesareusedwhentheengineandtransmission unitscombinedtogethertoformanintegralconstruction. Indirectlydrivenfinaldrivesareusedattherearofthevehiclebeingeithersprungandattachedthebodystructureorunsprungandincorporated intherear-axlecasing.Thefinal-drive gearsareusedinthetransmission systemforthefollowingreasons[1]:(a)toredirectthedrivefromthegearboxorpropeller shaftthrough90°and,(b) toprovideapermanent gearreduction betweentheengineandtheroad-wheels. Invehicles,differential isthemainpartwhichtransmitsthemovementcomingfromtheenginetothewheelsOnasmoothroad,thecomes tobothwheels evenly. Theinner wheel should turnlessandtheouter wheel should turnmoretodotheturning without lateralslippingandbeingflung.Differential, whichisgenerallyplacedinthemiddlepartoftherearbridge,consistsofpiniongear,mirrorgear,differential box,twoaxlegearandtwopinionspidergears.Aschematicillustration ofadifferential isgiveninFig,1.ThetechnicaldrawingofpinionthefracturedshaftisalsogiveninFig,2,Fig.3showsthephotographofthefracturedpinionshaftandthefracturesectionisindicated.In differentials,andpiniongeararemadetogetusedtoeachotherduringmanufacturing andthesameserialnumberisgiven.Bothofthemareoncondition thatthereareanyproblems. Inthesesystems, thecommondamageisthewearofgears[2-4].Inthisstudy,thepinionofthedifferential ofaminibushasbeeninspected. Theminibusisadieselvehicledrivenattherearaxleandhasapassengercapacityof15people.Maximumenginepoweris90/4000HP/rpm,andmaximumtorqueis205/1600Nm/rpm.Itstransmission boxhasmanualsystem(5forward,1back).Thedamagewascausedbystoppingandstartingtheminibusatatrafficlights.Inthisdifferential, entranceshaftwhichcarriesthepiniongearwasbroken. Various studies havebeenmadetodetermine thetypeandpossible reasons ofthedamage. Theseare:?studies carried outtodetermine thematerialoftheshaft;?studiescarriedouttodeterminethemicro-structure; ?studiesrelatedtothefracturesurface.Thereisacloserphotographofthefractured surfacesandfractureareainFig.4.Thefracturewascausedbytakingoutcircularmarkgearseeninthemiddleofsurfaces.2.ExperimentalprocedureSpecimens extractedfromtheshaftweresubjectedtovarioustestsincludinghardnesstestsandmetallographicandscanningelectronmicroscopyaswellasthedeterminationofchemicalcomposition.Alltestswerecarriedoutatroomtemperature.2.1 Chemicalandmetallurgical analysisChemicalanalysisofthefractureddifferentialmaterialwascarriedoutusingaspectrometer. Thechemicalcomposition ofthematerialisgiveninTable1.Chemicalcomposition showsthatthematerialisalowalloycarburizing steeloftheAISI8620type.Hardenability ofthissteelisverylowbecauseoflowcarbonproportion.Therefore,surfaceareabecomeshardandhighlyenduring,andinnerareasbecomestoughbyincreasing carbonproportion onthesurfaceareawithcementation operation. Thisisthekindofsteelwhichisgenerally usedinmechanical partssubjected dotorsionandbending.Highresistance isobtainedonthesurfaceandhighfatigueendurance valuecanbeobtainedwithcompressiveresidual stressbymakingthesurfaceharder[5-7].In whichalloyelements distribute themselves incarbonsteelsdependsprimarily onthecompound andcarbideformingtendencieseachelement. Nickeldissolves intheαferrite ofthesteelsinceithaslesstendency toformcarbides thanironSilicon combines tolimitedextentwiththeoxygenpresentinthesteeltoformnonmetallic inclusions butotherwise dissolves intheferrite.Mostofthemanganese addedcarbonsteelsdissolvesintheferrite.Chromium,whichhasasomewhatstrongercarbide-forming dependsontheiron,partitionsbetweentheferriteandcarbidephases.distributionofchromiumdependsontheamountofcarbonpresentandifotherstrongercarbide-forming elementssuchastitaniumandcolumbiumamountofcarbonpresentandifotherstrongercarbide-forming elementssuchastitaniumandcolumbiumareabsent.Tungstenandmolybdenumcombinewithcarbontoformcarbidesisthereissufficientcarbonpresentandifotherstrongercarbide-forming elementssuchdatitaniumandcolumbiumareabsent.Manganeseandnickellowertheeutectoidtemperature[8].Preliminarystructural examination ofthefaileddifferential materialisshowninFig.5.Itcanbeseenthatthematerialhasamixedstructureinsomeferrite existprobably asaresult ofslowcooling andhighSicontent. HighSicontent inthistypeofsteelimproves thetreatmentsusceptibility aswellasanimprovementofyieldstrengthandmaximumstresswithoutanyreductionofductility[9].Ifthemicro-structure cannotbeinvertedtomartensitebyquenching,areductionoffatiguelimitisobserved.There areareaswithcarbonphaseinFig.5(a).ThereisthetransitionboundaryofinFig.5(b)and(c)showsthematrixregionwithoutcarburization. Asfarasitisseenintherephotographs, thepiecewasfirstthenthequenchingoperationwasdonethantempered.Thissituationcanbeunderstood fromblindmartensite plates.2.2 HardnesstestsThehardnessmeasurements arecarriedoutbyaMetTest-HT typecomputer integrated hardness tester.Theloadis1471N.Themediumhardness valueoftheinterior regionsisobtained asobtainedas43HRC.Microhard-nessmeasurements havebeenmadetodeterminethechanceofhardnessvaluesalongcross-section be-causeofthehardeningofsurfaceduetocarburization. TheresultsofVickershardnessmeasurementunderaloadof4.903NareillustratedinTable2.2.3Inspectionofthefracturedirectobservations ofthepiecewithfracturedsurfacesandSEManalysesaregiveninthischapter.Thecrackstartedbecauseofapossibleproblemthebottomofnotchcausedtheshafttobebrokencompletely. Thecrackstartedontheouterpart,aftersometimeitcontinued beyondcentreandtherewasonlyalittlepartleft.Andthispartwasbrokenstatically duringsuddenstarting ofthevehicleatthetrafficlights.Asacharacteristic ofthefatigue,therearetworegionsinthefracturedsurface.Theseareasmoothsurfacecreatedbycrackpropagation。

中英文对照外文翻译(文档含英文原文和中文翻译)Failure analysis of an automobile differential pinion shaft AbstractDifferential is used to decrease the speed and to provide moment increase for transmitting the movement coming from the engine to the wheels by turning it according to the suitable angle in vehicles and to provide that inner and outer wheels turn differently. Pinion gear and shaft at the entrance are manufactured as a single part whereas they are in different forms according to automobile types. Mirror gear which will work with this gear should become familiar before the assembly. In case of any breakdown, they should be changed as a pair. Generally, in these systems there are wear damages in gears. The gear inspected in this study has damage as a form of shaft fracture.In this study, failure analysis of the differential pinion shaft is carried out. Mechanical characteristics of the material are obtained first. Then, the microstructure and chemical compositions are determined. Some fractographic studies are 2005 Elsevier Ltd. All rights reserved.Keywords: Differential; Fracture; Power transfer; Pinion shaft1. IntroductionThe final-drive gears may be directly or indirectly driven from the output gearing of the gearbox. Directly driven final drives are used when the engine and transmission units are combined together to form an integral construction. Indirectly driven final drives are used at the rear of the vehicle being either sprung and attached to the body structure or unsprung and incorporated in the rear-axle casing. The final-drive gears are used in the transmission system for the following reasons [1]:(a) to redirect the drive from the gearbox or propeller shaft through 90°and,(b) to provide a permanent gear reduction between the engine and the driving road-wheels.In vehicles, differential is the main part which transmits the movement coming from the engine to the wheels On a smooth road, the movement comes to both wheels evenly. The inner wheel should turn less and the outer wheel should turn more to do the turning without lateral slipping and being flung. Differential, which is generally placed in the middle part of the rear bridge, consists of pinion gear, mirror gear, differential box, two axle gear and two pinion spider gears.A schematic illustration of a differential is given in Fig, 1. The technical drawing of pinion the fractured pinion shaft is also given in Fig, 2, Fig. 3 shows the photograph of the fractured pinion shaft and the fracture section is indicated.In differentials, mirror and pinion gear are made to get used to each other during manufacturing and the same serial number is given. Both of them are changed on condition that there are any problems. In these systems, the common damage is the wear of gears [2-4]. In this study, the pinion shaft of the differential of a minibus has been inspected. The minibus is a diesel vehicle driven at the rear axle and has a passenger capacity of 15 people. Maximum engine power is 90/4000 HP/rpm, and maximum torque is 205/1600 Nm/rpm. Its transmission box has manual system (5 forward, 1 back). The damage was caused by stopping and starting the minibus at a traffic lights. In this differential, entrance shaft which carries the pinion gear was broken. Various studies have been made to determine the type and possible reasons of the damage. These are:•studies carried out to determine the material of the shaft;•studies carried out to determine the micro-structure;•studies related to the fracture surface.There is a closer photograph of the fractured surfaces and fracture area in Fig. 4. The fracture was caused by taking out circular mark gear seen in the middle of surfaces.2. Experimental procedureSpecimens extracted from the shaft were subjected to various tests including hardness tests and metallographic and scanning electron microscopy as well as the determination of chemical composition. All tests were carried out at room temperature.2.1 Chemical and metallurgical analysisChemical analysis of the fractured differential material was carried out using a spectrometer. The chemical composition of the material is given in Table 1. Chemical composition shows that the material is a lowalloy carburizing steel of the AISI 8620 type.Hardenability of this steel is very low because of low carbon proportion. Therefore, surface area becomes hard and highly enduring, and inner areas becomes tough by increasing carbon proportion on the surface area with cementation operation. This is the kind of steel which is generally used in mechanical parts subjected do torsion and bending. High resistance is obtained on the surface and high fatigue endurance value can be obtained with compressive residual stressby making the surface harder [5-7].In which alloy elements distribute themselves in carbon steels depends primarily on the compound and carbide forming tendencies of each element. Nickel dissolves in the αferrite of the steel since it has less tendency to form carbides than iron Silicon combines to a limited extent with the oxygen present in the steel to form nonmetallic inclusions but otherwise dissolves in the ferrite. Most of the manganese added to carbon steels dissolves in the ferrite. Chromium, which has a somewhat stronger carbide-forming depends on the iron, partitions between the ferrite and carbide phases. The distribution of chromium depends on the amount of carbon present and if other stronger carbide-forming elements such as titanium and columbium amount of carbon present and if other stronger carbide-forming elements such as titanium and columbium are absent. Tungsten and molybdenum combine with carbon to form carbides is there is sufficient carbon present and if other stronger carbide-forming elements such da titanium and columbium are absent. Manganese and nickel lower the eutectoid temperature [8]. Preliminary micro structural examination of the failed differential material is shown in Fig. 5. It can be seen that the material has a mixed structure in which some ferrite exist probably as a result of slow cooling and high Si content. High Si content in this type of steel improves the heat treatment susceptibility as well asan improvement of yield strength and maximum stress without any reduction of ductility [9]. If the micro-structure cannot be inverted to martensite by quenching, a reduction of fatigue limit is observed.There are areas with carbon phase in Fig. 5(a). There is the transition boundary of carburization in Fig. 5(b) and (c) shows the matrix region without carburization. As far as it is seen in there photographs, the piece was first carburized, then the quenching operation was done than tempered. This situation can be understood from blind martensite plates.2.2 Hardness testsThe hardness measurements are carried out by a MetTest-HT type computer integrated hardness tester. The load is 1471 N. The medium hardness value of the interior regions is obtained as obtained as 43 HRC. Micro hard-ness measurements have been made to determine the chance of hardness values along cross-section be-cause of the hardening of surface area dueto carburization. The results of Vickers hardness measurement under a load of 4.903 N are illustrated in Table 2.2.3 Inspection of the fractureThe direct observations of the piece with fractured surfaces and SEM analyses are given in this chapter. The crack started because of a possible problem in the bottom of notch caused the shaft to be broken completely. The crack started on the outer part, after some time it continued beyond the centre and there was only a little part left. And this part was broken statically during sudden starting of the vehicle at the traffic lights. As a characteristic of the fatigue , there are two regions in the fractured surface. These are a smooth surface created by crack propagation and a rough surface created by sudden fracture. These two regions can be seen clearly for the entire problem as in Fig. 4. The fatigue crack propagation region covers more than 80% of the cross-section.Shaft works under the effect of bending, torsion and axial forces which affect repeatedlydepending on the usage place. There is a sharp fillet at level on the fractured section. For this reason, stress concentration factors of the area have been determined. K t = 2.4 value (for bending and tension), and K t = 1.9 value (for torsion) have been acquired according to calculations. These are quite high values for areas exposed to combined loading.These observations and analysis show that the piece was broken under the influence of torsion with low nominal stresses electron microscopy shows that the fracture has taken place in a ductile manner (Fig.6). There are some shear lips in the crack propagation region which is a glue of the plastic shear deformations. Fig. 7 shows the beach marks of the fatigue crack propagation. The distance between any lines is nearly 133 nm.3. ConclusionsA failed differential pinion shaft is analysed in this study. The pinion shaft is produced from AISI 8620 low carbon carburising steel which had a carbursing, quenching and tempering heat treatment process. Mechanical properties, micro structural properties, chemical compositions and fractographic analyses are carried out to determine the possible fracture reasons of the component. As a conclusion, the following statements can be drawn:•The fracture has taken place at a region having a high stress concentration by a fatigue procedure under a combined bending, torsion and axial stresses having highly reversible nature.•The crack of the fracture is initiated probably at a material defect region at the critical location.•The fracture is taken place in a ductile manner.•Possible later failures may easily be prevented by reducing the stress concentration at the critical locationAcknowledgementThe author is very indebted to Prof. S. Tasgetiren for his advice and recommendations during the srudy.References[1]Heisler H. Vehicle and engine technology. 2nd ed. London: SAE International; 1999.[2]Makevet E, Roman I. Failure analysis of a final drive transmission in off-road vehicles. EngFailure Anal 2002;9:579-92.[3]Orhan S, Aktu ¨rk N. Determination of physical faults in gearbox through vibrationanalysis. J Fac Eng Arch Gazi University 2003;18(3):97–106..[4]Tasgetiren S, Aslantas ? K, Ucun I. Effect of press-fitting pressure on the fatiguedamages of root in spur gears. Technol Res: EJMT 2004;2:21–9.[5]Nanawarea GK, Pableb MJ. Failures of rear axle shafts of 575 DI tractors. EngFailure Anal 2003;10:719–24.[6]Aslantas K, Tasgetiren S. A study of spur gear pitting formation and life prediction.Wear 2004;257:1167–75.[7]Savas V, O ¨ zek C. Investigation of the distribution of temperature on a shaft withrespect to the deflection. Technol Res: EJMT 2005;1:33–8.[8]Smith FW. Principles of materials science and engineering. 3rd ed. USA: McGraw-HillSeries; 1996. p. 517–18.[9]ASM metal handbook, vol. 1. Properties and selection, irons, steels, and highperformance alloys; 1991.[10]Voort GFV. Visual examination and light microscopy. ASM handbook metallographyand microstructures. Materials Park (OH): ASM International; 1991. p. 100–65.汽车差速器小齿轮轴的失效分析摘要差速器是用来降低速度增加扭矩并根据合适的角度向两轮传递动力。

DIFFERENTIAL AND REAR AXLESThe differential is part of the rear-axle-housing assembly,which includes the differential,rear axles,wheels,and bearing.If the car were to be driven in a straight line without having to make turns,then no differential would be necessary.However,when the car rounds a turn,the outer wheel must travel farther than the inner wheel.The differential permits the two rear wheels to rotate different amounts when the car goes around a turn , while still delivering power to both rear wheels.The rear axles are attached to the wheels and have bevel side gears on their inner ends.The differential case is assembled on the left axle but can rotate on a bearing independently of the axle.The differential case supports the differential-pinion gear on a shaft,and this gear meshes with the two bevel gears.The fing gear is attached to the differential case so that the case rotates with the fing gear when the latter is driven by the drive pinion.The driving power enters the differential through the drive pinion on the end of the propeller shaft.The drive pinion is meshed with a large ring gear so that the ring gear revoves with the pinion.Attached to the ring gear is a differential-pinion shaft on which are assembled two differential-pinion gears.Each rear car wheel has a separate axle, and there are two side gears splined to the inner ends of the two wheel axles.The two side gears.When the car is on a straighet road ,the two differential-pinion gears do not rotate on the pinion shaft ,but they do exert pressure on the two side gears turn at the same speed as the ring gear ,causing both rear wheels to turn at the same speed,also.When the car rounds a curve ,the outer wheel must turn faster than the inner wheel,To permit this,the two pinino gears rotate on their pinion shaft,transmitting more turning movement to the outer side gear that to the inner side gear.Thus,the side gear on the outer-wheel axle turns more rapidly than the side gear on the inner wheel axle.This permits the outer wheel to turn more rapidly while the car is rounding the curve.There are two basic types of axle:deed axles and live axle.The dead axle does not rotate; the wheel rotates on it.A common exmple is the axle on a horse-drawn wagon.Live axles are attached to the wheel so that both the wheel and the axle rotate together.Live axles are classified according to the manner in which they are supported:semifloating, three-quarer-floating,and full-floating.AUTOMOBILE SYSTEMThe fuel system has the job of supplying a combustible mixture of air and fuel to the engine. The fuel system must vary the proportions of air and fuel to suit different operating conditions. When the engine is cold, for example, then the mixture must be rich（have a high proportion of fuel）.The reason for this is that the fuel does not vaporize rapidly at low temperatures. Therefore, extra fuel must be added to the mixture so that there will be enough vaporized fuel to form a combustible mixture.The fuel system consists of the fuel tank, fuel pump, fuel filter, carburetor, intake manifold, and fuel lines, or tubes, connecting the tank, pump, and carburetor. Some gasoline engines use a fuel-injection system; in this system, a fuel-injection pump replaces the carburetor.The fuel tank, in which gasoline is stored, is normally located at the rear of the vehicle. It is made of sheet metal and is attached to the frame.A fuel pump delivers fuel from the tank to the carburetor. There are two general types of fuel pump, mechanical and electric.The fuel system has filters and prevent dire in the fuel from entering the fuel pump or carburetor. Dirt could, of course, prevent normal operation of these units and cause poor engine performance.The carburetor is essentially a mixing device which mixes liquid gasoline with air. In this process, it throws a fine spray of gasoline into air passing through the carburetor on its way to the engine. The gasoline vaporizes and mixes with the air to form a highly combustion chambers, where it is ignited. It burns, causing the engine to produce power. The mixture must be of varying degrees of rich nice to suit engine operating conditions.It must be rich（have a higher percentage of fuel）for starting, acceleration, and high-speed operation. And it should lean to（become less rich）for operation at intermediate speed with a worm engine. The carburetor has several different circuits, or passages, through which fuel and air-fuel mixture flow under different operating conditions to produce the varying richness of the air-fuel mixture.The purpose of the cooling system is to keep the engine at its most efficient operating temperature at all engine speeds and all drilling conditions.A great deal of heat is produced in the engine by the burning of the air-fuel mixture. Some of this heat escapes from the engine through the exhaust gases（the hot gases left after the gasoline is burned）. But enough remains in the engine to cause serious trouble unless removed by some other means. The cooling system takes care of this additional heat.The cooling system is built into the engine. There are hollow spaces around each engine cylinder and combustion chamber. These hollow spaces are called waterjackets, since they are filled with water. When the engine is running, the water takes heat from the engine, becoming hot in the process.A water pump pumps the hot water from the engine water jackets into the radiator. The radiator has two sets of passages. One set carries air（pulled through by car motion and the engine fan）. As the hot water passes through, it gives up its heat to the air passing through. The cooled water then reenters the engine, where it can pick up more heat. In operation, water continuously circulates between the engine and radiator, carrying heat from the engine temperatures are prevented.Two general types of cooling systems are used, air cooling and liquid cooling. The liquid cooling system consists of water pumps, water jackets, engine fan, radiator and so on. The water pump, driven by a belt from the engine crankshaft, circulates the cooling liquid between the radiator andengine water jackets. The cooling liquid is water. Antifreeze compounds are added to the water during the winter. The water jacket are cast into the cylinder blocks and heats. The engine fan is usually mounted on the water-pump shaft and is driven by the same belt that drives the pump shaft and the generator. The purpose of the fan is to provide a powerful draft of air through the radiator. The radiator is a device for holding a large volume of air so that heat will transfer from the water to the air. The radiator core is divided into two separate compartments; water passes through one, and air passes through the other.The ignition system is part of the electric system of the automobile. Its purpose is to produce high-voltage surges（up to 20 000 volts）and to deliver them to the combustion chambers in the engine. These high-voltage surge surges then cause electric sparks in the combustion chambers. The sparks ignite, or set fire to, the air-fuel mixture in the combustion chambers so that it burns and cause the engine ton operate.The ignition system consists three basic parts: the ignition distributor, the ignition coil, and the spark plug, together with the connecting wires. When the engine is running, the ignition coil is repeatedly connected, it becomes loaded with electrical energy. Then, when it is disconnected, the “load” of electrical energy is released in a high-voltage. This surge flows through the wiring to the spark plug in the engine cylinder that is ready to fire.You must understand that all this takes place very rapidly. At high speed, the whole series of events happens in less than one three-hundredth of a second. That is, there will be as many as 300 of these events every second that the engine is running at high speed.Some systems use transistors to reduce the load on the distributor contract points. Other systems do not have contract points use instead a combination of transistors and a magnetic pick-up in the distributor.The ignition distributor has two jobs. First, it closes and opens the circuit between the battery and the ignition coil. The distributors second job is to distribute each high-voltage surge to the correct spark plug at the correct instant by means of the distributor rotor and cap and secondary wiring.There are two basic types of distributor:（1）the type using contact points to close and open the coil primary circuit;（2）the type using a magnetic pick-up and a transistor control unit to interrupt the current flow of the coil primary circuit.Automobile engines are not self-starts. In order to start them, the engine crankshaft must be turned over by some outside means so as to（a）admit air-fuel mixture to the cylinder, and（b）cause the mixture to fire.In the case of automobile engines, the mixture in the cylinder, after being compressed, must be not enough to ignite. This requires that the engine be turned over with sufficient speed. If the engine is turned over too slowly, the unavoidable small leaks past the piston rings and also through the intake and exhaust valves of four-circle engines will permit a substantial part of the fuel-air mixture to escape during the compression stroke. Also, the heat loss from the compressed air to the cylinder walls will be greater at low speed because of the longer exposure. The escape of air and the loss of heat both result in a lower temperature at the end of compression. Therefore, there is a minimum speed which the engine must attain before ignition will occur and the engine will begin firing. The starting speed depends upon the type and size of the engine, its condition, and the temperature of the air entering engine.The starting system contains a cranking, or starting, motor and other accessories.The starting motor electrically cranks the engine for starting. It is a special direct-current motor operating on battery voltage and is mounted on the engine flywheel house. The starter changes the electrical current into the mechanical energy to push the crank-shaft round. By means of this, the engine can be started. The cranking motor consists of the commutator end head, holding the brushes; the field frame, into which the field windings are assembled around pole shoes; the drive housing, which house the drive assembly and supports the motor on the engine flywheel housing; the armature; and the drive assembly. Some cranking motors also have a solenoid that operates the shift lever.Cranking-motor controls have varied from a simple foot-operated pedal to automatic devices that close the cranking-motor circuit when the accelerator pedal is depressed.The present system that has been almost universally adopted for passenger cars and many other vehicles has starting contacts in the ignition switch. When the ignition key is turned against spring pressure past the ON position to START, the starting contacts close. This connects the cranking-motor solenoid or magnetic switch to the battery. After the engine starts and the ignition key is released, spring pressure returns it to the ON position.The starting motor should not be operated more than 5 seconds during each starting operating, for the sake of recovering the energy of battery. It will not be allowed to start it again until its stopped for fifteen seconds.The manual transmission shown in Fig.—1 provides a means of varying the relationship between the speed of the engine and the speed of the wheels .Varying these gear ratios allows the right amount of engine power at many different speeds.Manual transmission requires use of a clutch to apply and remove thetorque to the transmission input shaft. The clutch allows this to happen gradually a so that the car can be started from a complete stop.Modern manual transmissions do not disengage any of the forward drive gears, they are simply connected to their shafts through the use of “synchronizers”.Reverse is achieved reverse idler gears ,which are engaged to move the car backwards.Some manual transmissions have an “overdrive”. An overdrive is a mechanical unit bolted to rear of the transmission. It is usually known as the fifth gear .When you use it, it will reduce the engine speed by about one-third ,which maintaining the same road speed.In an automatic transmission, gear ratios are changed automatically. This eliminates the need for the driver to operate the clutch and manually “shift gears.”The typical automatic transmission combines a fluid torque converter , a planetary-gear system, and a hydraulic control system in a single unit. As car speed changes , various gear ratios between the crankshaft and the wheels are selected and then changed automatically. Automatic controls inside the transmission supply the proper ratio for the driving condition. In addition to the forward-gear ratios, neutral, and reverse, the automatic transmission has a PAPK position. This locks the transmission to prevent the car from moving or rolling away while parked.差速器和车桥差速器和后桥壳总成的一个部件，后桥壳总成包括差速器、后桥、车轮和轴承。

外文翻译汽车差速器Failure analysis of an automobile differential pinion shaftAbstractDifferential is used to decrease the speed and to provide moment increase for transmitting the movement coming from the engine to the wheels by turning it according to the suitable angle in vehicles and to provide that inner and outer wheels turn differently. Pinion gear and shaft at the entrance are manufactured as a single part whereas they are in different forms according to automobile types. Mirror gear which will work with this gear should become familiar before the assembly. In case of any breakdown, they should be changed as a pair. Generally, in these systems there are wear damages in gears. The gear inspected in this study has damage as a form of shaft fracture.In this study, failure analysis of the differential pinion shaft is carried out. Mechanical characteristics of the material are obtained first. Then, the microstructure and chemical compositions are determined. Some fractographic studies are carried out to asses the fatigue and fracture conditions.Keywords: Differential; Fracture; Power transfer; Pinion shaft1. IntroductionThe final-drive gears may be directly or indirectly driven from the output gearing of the gearbox. Directly driven final drives are used when the engine and transmission units are combined together to form an integral construction. Indirectly driven final drives are used at the rear of the vehicle being either sprung and attached to the body structure or unsprung and incorporated in the rear-axle casing. The final-drive gears are used in the transmission system for the following reasons [1]:(a) to redirect the drive from the gearbox or propeller shaft through 90° and,(b) to provide a permanent gear reduction between the engine and the driving road-wheels.In vehicles, differential is the main part which transmits the movement coming from the engine to the wheels. On a smooth road, the movement comes to both wheels evenly. The inner wheel should turn less and the outer wheel should turn more to do the turning without lateral slipping and being flung. Differential, which is generally placed in the middle part of the rear bridge, consists of pinion gear, mirror gear, differential box, two axle gear and two pinion spider gears.A schematic illustration of a differential is given in Fig. 1. The technical drawing of the fractured pinion shaft is also given in Fig. 2. Fig. 3 shows the photograph of the fractured pinion shaft and the fracture section is indicated.In differentials, mirror and pinion gear are made to get used to each other during manufacturing and the same serial number is given. Both of them are changed on condition that there are any problems. In these systems, the common damage is the wear of gears [2–4]. In this study, the pinion shaft of the differential of aminibus has been inspected. The minibus is a diesel vehicle driven at the rear axle and has a passenger capacity of 15 people. Maximum engine power is 90/4000 HP/rpm, and maximum torque is 205/1600 Nm/rpm. Its transmission box has manual system (5 forward, 1 back). The damage was caused by stopping and starting the minibus at atraffic lights. In this differential, entrance shaft which carries the pinion gear was broken. Various studies have been made to determine the type and possible reasons of the damage.These are:studies carried out to determine the material of the shaft;studies carried out to determine the micro-structure;studies related to the fracture surface.There is a closer photograph of the fractured surfaces and fracture area in Fig. 4. The fracture was caused by taking out circular mark gear seen in the middle of surfaces.Fig. 1. Schematic of the analysed differential.Fig. 2. Technical drawing of the analysed pinion shaftFig. 3. The picture of the undamaged differential pinion analysed in the studyFig. 4. Photographs of failed shaft2. Experimental procedureSpecimens extracted from the shaft were subjected to various tests including hardness tests and metallographic and scanning electron microscopy as well as the determination of chemical composition. All tests were carried out at room temperature.2.1. Chemical and metallurgical analysisChemical analysis of the fractured differential material was carried out using a spectrometer. The chemical composition of the material is given in Table 1. Chemical composition shows that the material is a low alloy carburising steel of the AISI 8620 type.Hardenability of this steel is very low because of low carbon proportion. Therefore, surface area becomes hard and highly enduring, and inner areas becomes tough by increasing carbon proportion on the surface area with cementation operation. This is the kind of steel which is generally used in mechanical parts subjected do torsion and bending. High resistance is obtained on the surface and high fatigue endurance value can be obtained with compressive residual stress by making the surface harder [5–7].In which alloy elements distribute themselves in carbon steels depends primarily on the compound- and carbide-forming tendencies of each element. Nickel dissolves in the a ferrite of the steel since it has less tendency to form carbides than iron. Silicon combines to a limited extent with the oxygen present in the steel to form nonmetallic inclusions but otherwise dissolves in the ferrite. Most of the manganese added tocarbon steels dissolves in the ferrite. Chromium, which has a somewhat stronger carbide-forming tendency than iron, partitions between the ferrite and carbide phases. The distribution of chromium depends on the amount of carbon present and if other stronger carbide-forming elements such as titanium and columbium are absent. Tungsten and molybdenum combine with carbon to form carbides if there is sufficient carbon present and if other stronger carbide-forming elements such as titanium and columbium are absent. Manganese and nickel lower the eutectoid temperature [8].Preliminary micro structural examination of the failed differential material is shown in Fig. 5. It can be seen that the material has a mixed structure in which some ferrite exist probably as a result of slow cooling and high Si content. High Si content in this type of steel improves the heat treatment susceptibility as well as an improvement of yield strength and maximum stress without any reduction of ductility [9]. If the microstructure cannot be inverted to martensite by quenching, a reduction of fatigue limit is observed.Table 1Chemical analysis of the pinion gear material (wt%)Fe C Si Mn P S Cr Mo Ni 96.92 0.235 0.252 0.786 0.044 0.016 0.481 0.151 0.517 and fracture surfaces.Fig. 5. Micro structure of the material (200·).There are areas with carbon phase in Fig. 5(a). There is the transition boundary of carburisation in Fig. 5(b) and (c) shows the matrix region without carburisation. As far as it is seen in these photographs, the piece was first carburised, then the quenching operation was done and than tempered. This situation can be understood from blind martensite plates.2.2. Hardness testsThe hardness measurements are carried out by a MetTest-HT type computer integrated hardness tester. The load is 1471 N. The medium hardness value of the interior regions is obtained as 43 HRC. Micro hardness measurements have been made to determine the chance of hardness values along the cross-section because of the hardening of surface area due to carburisation. The results of Vickers hardness measurement under a load of 4.903 N are illustrated in Table 2.2.3. Inspection of the fractureThe direct observations of the piece with fractured surfaces and SEM analyses are given in this chapter. The crack started because of a possible problem in the bottom of notch caused the shaft to be broken completely. The crack started on the outer part, after some time it continued beyond the centre and there was only a little part left. And this part was broken statically during sudden starting of the vehicle at the traffic lights. As a characteristic of the fatigue fracture, there are two regions in the fractured surface. These are a smooth surface created by crack propagation and a rough surface created by sudden fracture. These two regions can be seen clearly for the entire problem as in Fig. 4. The fatigue crack propagation region covers more than 80% of the cross-section.Table 2Micro hardness values Distance from surface (lm) 50 100 200 400 CenterValues HV (4903N) 588 410 293 286 263Fig.Fig. 6. SEM image of the fracture surface showing the ductile shear.Fig. 7. SEM image of the fracture surface showing the beach marks of the fatigue crack propagation.Shaft works under the effect of bending, torsion and axial forces which affect repeatedly depending on the usage place. There is a sharp fillet at level on the fractured section. For this reason, stress concentration factors of the area have been determined. Kt = 2.4 value (for bending and tension) and Kt = 1.9 value (for torsion) have been acquired according to calculations. These are quite high values for areas exposed to combined loading.These observations and analysis show that the piece was broken under the influence of torsion with low nominal stresses and medium stress concentration [10].The scanning electron microscopy shows that the fracture has taken place in a ductile manner (Fig. 6). There are some shear lips in the crack propagation region which is a glue of the plastic shear deformations. Fig. 7 shows the beach marks of the fatigue crack propagation. The distance between any two lines is nearly 133 nm.3. ConclusionsA failed differential pinion shaft is analysed in this study. The pinion shaft is produced from AISI 8620 low carbon carburising steel which had a carburising, quenching and tempering heat treatment process. Mechanical properties, micro structural properties, chemical compositions and fractographic analyses are carried out to determine the possible fracture reasons of the component. As a conclusion, the following statements can be drawn:The fracture has taken place at a region having a high stress concentration by a fatigue procedure under a combined bending, torsion and axial stresses having highly reversible nature.The crack of the fracture is initiated probably at a material defect region at the critical location.The fracture is taken place in a ductile manner.Possible later failures may easily be prevented by reducing the stress concentration at the critical location.AcknowledgementThe author is very indebted to Prof. S. Tasgetiren for his advice and recommendations during the study.H. Bayrakceken / Engineering Failure Analysis 13 (2006) 1422–1428References[1] Heisler H. Vehicle and engine technology. 2nd ed. London: SAE International; 1999.[2] Makevet E, Roman I. Failure analysis of a final drive transmission in off-road vehicles. Eng Failure Anal 2002;9:579–92.[3] Orhan S, Aktu¨rk N. Determination of physical faults in gearbox through vibration analysis. J Fac Eng Arch Gazi University2003;18(3):97–106.[4] Tas getiren S, Aslantas K, Ucun I. Effect of press-fitting pressure on the fatigue damages of root in spur gears. Technol Res: EJMT2004;2:21–9.[5] Nanawarea GK, Pableb MJ. Failures of rear axle shafts of 575 DI tractors. Eng Failure Anal 2003;10:719–24.[6] Aslantas K, Tas getiren S. A study of spur gear pitting formation and life prediction. Wear 2004;257:1167–75.[7] Savas V, O¨ zek C. Investigation of the distribution of temperature on a shaft with respect to the deflection. Technol Res: EJMT2005;1:33–8.[8] Smith FW. Principles of materials science and engineering. 3rd ed. USA: McGraw-Hill Series; 1996. p. 517–18.[9] ASM metal handbook, vol. 1. Properties and selection, irons, steels, and high performance alloys; 1991.[10] Voort GFV. Visual examination and light microscopy. ASM handbook metallography and microstructures. Materials Park(OH): ASM International; 1991. p. 100–65.汽车差速器小齿轮轴的失效分析摘要差速器的作用是根据车辆合适的角度, 通过将运动转向, 为运动传输减速或者提供瞬间加速, 这个运动来自引擎, 到车轮去, 使内外车轮转动不同。

中英文对照外文翻译(文档含英文原文和中文翻译)Failure analysis of an automobile differential pinion shaft AbstractDifferential is used to decrease the speed and to provide moment increase for transmitting the movement coming from the engine to the wheels by turning it according to the suitable angle in vehicles and to provide that inner and outer wheels turn differently. Pinion gear and shaft at the entrance are manufactured as a single part whereas they are in different forms according to automobile types. Mirror gear which will work with this gear should become familiar before the assembly. In case of any breakdown, they should be changed as a pair. Generally, in these systems there are wear damages in gears. The gear inspected in this study has damage as a form of shaft fracture.In this study, failure analysis of the differential pinion shaft is carried out. Mechanical characteristics of the material are obtained first. Then, the microstructure and chemical compositions are determined. Some fractographic studies are 2005 Elsevier Ltd. All rights reserved.Keywords: Differential; Fracture; Power transfer; Pinion shaft1. IntroductionThe final-drive gears may be directly or indirectly driven from the output gearing of the gearbox. Directly driven final drives are used when the engine and transmission units are combined together to form an integral construction. Indirectly driven final drives are used at the rear of the vehicle being either sprung and attached to the body structure or unsprung and incorporated in the rear-axle casing. The final-drive gears are used in the transmission system for the following reasons [1]:(a) to redirect the drive from the gearbox or propeller shaft through 90°and,(b) to provide a permanent gear reduction between the engine and the driving road-wheels.In vehicles, differential is the main part which transmits the movement coming from the engine to the wheels On a smooth road, the movement comes to both wheels evenly. The inner wheel should turn less and the outer wheel should turn more to do the turning without lateral slipping and being flung. Differential, which is generally placed in the middle part of the rear bridge, consists of pinion gear, mirror gear, differential box, two axle gear and two pinion spider gears.A schematic illustration of a differential is given in Fig, 1. The technical drawing of pinion the fractured pinion shaft is also given in Fig, 2, Fig. 3 shows the photograph of the fractured pinion shaft and the fracture section is indicated.In differentials, mirror and pinion gear are made to get used to each other during manufacturing and the same serial number is given. Both of them are changed on condition that there are any problems. In these systems, the common damage is the wear of gears [2-4]. In this study, the pinion shaft of the differential of a minibus has been inspected. The minibus is a diesel vehicle driven at the rear axle and has a passenger capacity of 15 people. Maximum engine power is 90/4000 HP/rpm, and maximum torque is 205/1600 Nm/rpm. Its transmission box has manual system (5 forward, 1 back). The damage was caused by stopping and starting the minibus at a traffic lights. In this differential, entrance shaft which carries the pinion gear was broken. Various studies have been made to determine the type and possible reasons of the damage. These are:•studies carried out to determine the material of the shaft;•studies carried out to determine the micro-structure;•studies related to the fracture surface.There is a closer photograph of the fractured surfaces and fracture area in Fig. 4. The fracture was caused by taking out circular mark gear seen in the middle of surfaces.2. Experimental procedureSpecimens extracted from the shaft were subjected to various tests including hardness tests and metallographic and scanning electron microscopy as well as the determination of chemical composition. All tests were carried out at room temperature.2.1 Chemical and metallurgical analysisChemical analysis of the fractured differential material was carried out using a spectrometer. The chemical composition of the material is given in Table 1. Chemical composition shows that the material is a lowalloy carburizing steel of the AISI 8620 type.Hardenability of this steel is very low because of low carbon proportion. Therefore, surface area becomes hard and highly enduring, and inner areas becomes tough by increasing carbon proportion on the surface area with cementation operation. This is the kind of steel which is generally used in mechanical parts subjected do torsion and bending. High resistance is obtained on the surface and high fatigue endurance value can be obtained with compressive residual stressby making the surface harder [5-7].In which alloy elements distribute themselves in carbon steels depends primarily on the compound and carbide forming tendencies of each element. Nickel dissolves in the αferrite of the steel since it has less tendency to form carbides than iron Silicon combines to a limited extent with the oxygen present in the steel to form nonmetallic inclusions but otherwise dissolves in the ferrite. Most of the manganese added to carbon steels dissolves in the ferrite. Chromium, which has a somewhat stronger carbide-forming depends on the iron, partitions between the ferrite and carbide phases. The distribution of chromium depends on the amount of carbon present and if other stronger carbide-forming elements such as titanium and columbium amount of carbon present and if other stronger carbide-forming elements such as titanium and columbium are absent. Tungsten and molybdenum combine with carbon to form carbides is there is sufficient carbon present and if other stronger carbide-forming elements such da titanium and columbium are absent. Manganese and nickel lower the eutectoid temperature [8]. Preliminary micro structural examination of the failed differential material is shown in Fig. 5. It can be seen that the material has a mixed structure in which some ferrite exist probably as a result of slow cooling and high Si content. High Si content in this type of steel improves the heat treatment susceptibility as well asan improvement of yield strength and maximum stress without any reduction of ductility [9]. If the micro-structure cannot be inverted to martensite by quenching, a reduction of fatigue limit is observed.There are areas with carbon phase in Fig. 5(a). There is the transition boundary of carburization in Fig. 5(b) and (c) shows the matrix region without carburization. As far as it is seen in there photographs, the piece was first carburized, then the quenching operation was done than tempered. This situation can be understood from blind martensite plates.2.2 Hardness testsThe hardness measurements are carried out by a MetTest-HT type computer integrated hardness tester. The load is 1471 N. The medium hardness value of the interior regions is obtained as obtained as 43 HRC. Micro hard-ness measurements have been made to determine the chance of hardness values along cross-section be-cause of the hardening of surface area dueto carburization. The results of Vickers hardness measurement under a load of 4.903 N are illustrated in Table 2.2.3 Inspection of the fractureThe direct observations of the piece with fractured surfaces and SEM analyses are given in this chapter. The crack started because of a possible problem in the bottom of notch caused the shaft to be broken completely. The crack started on the outer part, after some time it continued beyond the centre and there was only a little part left. And this part was broken statically during sudden starting of the vehicle at the traffic lights. As a characteristic of the fatigue , there are two regions in the fractured surface. These are a smooth surface created by crack propagation and a rough surface created by sudden fracture. These two regions can be seen clearly for the entire problem as in Fig. 4. The fatigue crack propagation region covers more than 80% of the cross-section.Shaft works under the effect of bending, torsion and axial forces which affect repeatedlydepending on the usage place. There is a sharp fillet at level on the fractured section. For this reason, stress concentration factors of the area have been determined. K t = 2.4 value (for bending and tension), and K t = 1.9 value (for torsion) have been acquired according to calculations. These are quite high values for areas exposed to combined loading.These observations and analysis show that the piece was broken under the influence of torsion with low nominal stresses electron microscopy shows that the fracture has taken place in a ductile manner (Fig.6). There are some shear lips in the crack propagation region which is a glue of the plastic shear deformations. Fig. 7 shows the beach marks of the fatigue crack propagation. The distance between any lines is nearly 133 nm.3. ConclusionsA failed differential pinion shaft is analysed in this study. The pinion shaft is produced from AISI 8620 low carbon carburising steel which had a carbursing, quenching and tempering heat treatment process. Mechanical properties, micro structural properties, chemical compositions and fractographic analyses are carried out to determine the possible fracture reasons of the component. As a conclusion, the following statements can be drawn:•The fracture has taken place at a region having a high stress concentration by a fatigue procedure under a combined bending, torsion and axial stresses having highly reversible nature.•The crack of the fracture is initiated probably at a material defect region at the critical location.•The fracture is taken place in a ductile manner.•Possible later failures may easily be prevented by reducing the stress concentration at the critical locationAcknowledgementThe author is very indebted to Prof. S. Tasgetiren for his advice and recommendations during the srudy.References[1]Heisler H. Vehicle and engine technology. 2nd ed. London: SAE International; 1999.[2]Makevet E, Roman I. Failure analysis of a final drive transmission in off-road vehicles. EngFailure Anal 2002;9:579-92.[3]Orhan S, Aktu ¨rk N. Determination of physical faults in gearbox through vibrationanalysis. J Fac Eng Arch Gazi University 2003;18(3):97–106..[4]Tasgetiren S, Aslantas ? K, Ucun I. Effect of press-fitting pressure on the fatiguedamages of root in spur gears. Technol Res: EJMT 2004;2:21–9.[5]Nanawarea GK, Pableb MJ. Failures of rear axle shafts of 575 DI tractors. EngFailure Anal 2003;10:719–24.[6]Aslantas K, Tasgetiren S. A study of spur gear pitting formation and life prediction.Wear 2004;257:1167–75.[7]Savas V, O ¨ zek C. Investigation of the distribution of temperature on a shaft withrespect to the deflection. Technol Res: EJMT 2005;1:33–8.[8]Smith FW. Principles of materials science and engineering. 3rd ed. USA: McGraw-HillSeries; 1996. p. 517–18.[9]ASM metal handbook, vol. 1. Properties and selection, irons, steels, and highperformance alloys; 1991.[10]Voort GFV. Visual examination and light microscopy. ASM handbook metallographyand microstructures. Materials Park (OH): ASM International; 1991. p. 100–65.汽车差速器小齿轮轴的失效分析摘要差速器是用来降低速度增加扭矩并根据合适的角度向两轮传递动力。

外文文献及译文文献题目：Differential shell process and boring tooling design 文献来源： Taylor&Francis文献发表日期： 2011年09月01日学生姓名：学号：系别：专业：指导教师：职称：2017年5月19日Differential shell process and boring tooling designThe motor car engine power transmission shaft and the clutch, and finally to drive around again assigned half shaft drive wheels, in this article, the drive power transmission way, it is the final assembly of the main parts is reducer and differential. Gear reducer is increased, the function of torque and completely on gear meshing gears, between are easy to understand. But more difficult to understand differential,what, why "differential differential"?The car is driven car differential main parts. It is in the power of both half shaft transmission shaft, allowing both half with different speed spinning wheels, satisfyboth pure rolling form as possible, reducing equidistant not tire and ground friction.spider diagramObject graph theory differentialfunctionalAt the turn of the car wheel track line, if the car is circular arc, turn left at the center, and at the same time, the wheels went arc length, the wheels than to balance the difference, left, and right wheel wheels slowlySlip differentialFaster, with different speed up the distance.If you make a whole after wheel, can accomplish on both sides of the wheel speed difference, is also does not have an automatic adjustment. In order to solve this problem, a hundred years ago, France Renault automotive company founder luis Renault will design a differential this thing.Slip differentialconstituteOrdinary differential planetary wheel planetary gear, by plane (differential shell), half axle gear parts etc. The power of the engine into the differential transmission.StructurePlanetary wheel frame, driven directly by the planets wheel drive, right and left two half shaft, wheel drive left and right. Meet the design requirements of differential (left) and the shaft speed (right)= 2 (axial rotational speed) planet round frame. When the car goes, left, right wheel and planetary wheel frame of equal speed, and in a state of equilibrium in the balance among car when turning round to destruction, reduce the speed, the wheel speed increase.StructurePrincipleThis adjustment is automatic differential here, involves "minimal energy consumption principle", namely earth all objects are tend to minimum energy. Such a grain of beans in a bowl, beans will automatically stays in the bowl bottom and never stay in the bowl wall, because the bowl bottom is the lowest energy (potential), it automatically select static (minimum) without energy. In the same Wheel in turning also will be the lowest power consumption tendency, automatically adjusted according to turn radius of the wheel speed around.A 3d effectWhen turning wheel, because the pull of the phenomenon, the medial wheel slip phenomenon, two driving wheel at will produce two opposite direction of additional force, due to the "principle of minimal energy consumption, will inevitably lead to the wheel speed different sides, thus destroyed the balance between three and half shaft are reflected by the half axle gear planetary gears, forced to produce the half shaft rotation speed, speed, the medial axis speed slow speed, so as to realize the difference on both sides wheels.If the drive wheels on both sides of the drive shaft with a whole rigid connection, only two wheels at the same Angle rotation. So, when the steering wheel, due to the lateral than inside the distance moved across the wheels, will make the scroll wheel on the slide, and drag on the scroll wheel inside the slip. Even the car run straight road gravamen, because although flat tire surface or rolling radius (but ranging from manufacturing error, wear different tyres, ranging from uneven pressure or carrying of sliding wheel) and cause.When the wheel sliding tire wear, not only aggravate increased power and fuel consumption, still can make steering difficulties, braking performance deteriorated. As for the wheels, and does not occur in structure sliding must ensure each wheelat different angles can rotate.Axis between differential driven wheels usually use bearing spindle support in the, can at any Angle rotation, and drive wheels with two and half shaft rigid connection, between two and half shaft with differential. The differential and called shaft between differential.Many of the drive shaft, and to make each off-road vehicle drive to different velocity rotating, in order to eliminate the bridge of the drive wheels, some in two axles sliding between between shaft with differential.Differential inspection1 differential shell doesn't have any properties of crack, shell and planetary gear differential half shaft washer, contact between gear, should be smooth without groove, If there is a slight groove or wear, can continue to use after grinding, or should be replaced or be repaired.2 the planetary gear differential shell and planetary gear wheel when the fitting clearance shall not greater than 0.1-0.15 mm, half axle gear shaft neck and shell hole for clearance, with no obvious loose labels should be replaced or feeling, or repair.Shell's processing technologyThe processing quality not only affects shell, the assembly precision and accuracy, but also affects the movement of the machine working accuracy, performance and life.There are many kinds of shell structure, its size and form with the structure of the machineand the shell in machine has the different function. But they remain on the analysis from the craft had a lot in common and its structure features are:(1) appearance is basically composed of six or five plane again into the closed-end polyhedron, integral and combined two,(2) structure shape is more complex. Inside the cavity is often, some places "partition wall, shell and uneven thickness thin.(3) shell walls are usually decorate have parallel hole or vertical hole,(4) on the shell, main processing is the number of plane, in addition to many higher accuracy and precision of supporting bearing with less demanding tighten pore.Shell parts technical requirements:(1) bearing support size precision and accuracy, surface roughness, requirements,(2) position precision including hole axis of the distance between the dimension precision, the same axis parallel degree in each hole, and Kong Duan facing the coaxial tolerance of vertical axis holes; etc.(3) to meet the needs and positioning of the shell processing machine assembly request, shell and assembly of shell with the datum plane positioning due and certain degree, and the surface roughness requirements, The bearing hole and assembling a certain distance between datum due to the accuracy requirement of.差速器壳体工艺及工装设计汽车发动机的动力经离合器、变速器、传动轴最后传送到驱动桥再左右分配给半轴驱动车轮，在这条动力传送途径上，驱动桥是最后一个总成，它的主要部件是减速器和差速器。

TRANSMISSIONManual transmission is one of the most common transmission, referred to as MT. Its basic structure in a single sentence is a central axis, two input shaft, namely, the axial and axial oart, they constituted the transmission of the subject, and, of course, a reverse axis. Manual transmission gear transmission and manual, contain can in axial sliding gears, through different meshing gears to change gear of torsional purpose. The typical structure and principle of the manual transmission.Input shaft also says, it's in front of the spline shaft directly with clutch platen, thus the spline set by the engine relay of torque. The first shaft gear meshing gears, often with oart as input shaft, and the gear on oart will turn. Also called shaft, because even more solid shaft of gear. The output shaft, and the second shaft position have the drive shaft gear, may at any time and under the influence of the control devices and the corresponding oart gear, thus changing the speed and torque itself. The output shaft is associated with tail spline shaft torque transmission shaft, through to drive to gear reducer.Predictably, transmission gear drive forward path is: input shaft gear - oart gnaws gnaws gear - because the second shaft gear - corresponding corresponding gear. Pour on the axle gear can also control device, by moving axis in the strike, and the output shaft gear and oart gear, in the opposite direction.Most cars have five forward and reverse gear, each one has certain ratio, the majority of gear transmission more than 1, 4 gears transmission is 1, called directly, and ratio is less than 1 of article 5 gear shift accelerated called. The output axis gear in the mesh position, can accept power transmission.Due to the gearbox output shaft to input shaft and the speed of their gear rotating, transform an "synchronization problem". Two rotating speed different meshing gears forcibly inevitable impact and collision damage gear. Therefore, the old transmission shift to use "two feet clutch" method, ShengDang in neutral position shift to stay for a while, in the space location on the door, in order to reduce gear speed. But this operation is more complex, difficult to grasp accurately. Therefore designers to create "synchronizer", through the synchronizer will make the meshing gears reach speed and smooth.Currently the synchronous transmission adopts is inertial synchronizer, it mainly consists of joints, synchronizer lock ring etc, it is characteristic of the friction effect on achieving synchronization. Mating, synchronizer and mating locking ring gear tooth circle have chamfering (locking horns), the synchronizer lock ring inside surface ofgear engagement ring and the friction surface contact. The lock horns with cone when designing the proper choice, has been made to the surface friction of meshing gears with gear synchronous, also can rapid produces a locking function, prevent the synchronous before meshing gears. When synchronous lock ring of gear engagement with surface contact surface, the outer circle in friction torque under the action of gear speed rapid decrease (increase) or to synchronous speed equal, both locking ring spun concurrent, relative to lock ring gear synchronous speed is zero, thus inertia moment also disappear, then in force, driven by the junction of unimpeded with synchronous lock ring gear engagement, and further to engagement with the engagement ring gear tooth and complete shift process. functional(1) change ratio, meet different driving conditions for traction engine, the need to work in the favorable conditions and meet the speed may request. In a wide range of vehicle speed changing the size and automobile driving wheel on the size of the torque. Due to the different demands, automobile driving conditions of vehicle speed and torque can drive in a broad range of change. For example, in high speed can be reached on 100km/h, while in the urban district, speed in 50km/h. In the empty flat roads, road, very little resistanceWhen carrying uphill, driving resistance was great. And the characteristics of automobile engine speed range is lesser, and torque changes more cannot meet the actual conditions range.(2) drive backward, to satisfy the need to drive car backwards. Realizing the backing, engine crankshaft are generally only to a direction, and sometimes need to back, so, often used in the transmission of reverse to realize the car drive backward.(3) in power, interruption, idle running engine starting, auto shift or need to stop the dynamic output, interrupted to transfer the power of the drive wheels.(4), when the clutch engagement realize gap, gearbox can not power output. For example, can ensure drivers in engine flameout loosen the clutch when leaving drivers seat.constituteBy continuously variable transmission gearbox and speed control two parts. The main function of the variable transmission torque and speed is the change of numerical and direction, The main function of the operation is controlled transmission mechanism, realize the transformation of transmission ratio, shift to speed torque. Principle,Mechanical transmission main application of the principle of gear transmission velocity. Say simply, there are a number of different transmission gearbox group of gear pair of vehicle, and behavior, is also shifting gears trunk by manipulating institutions make different gearpair work. As in low-speed, ratio of gear pair work, and in high-speed, let ratio of small gear pair work.Classification,1, according to the change of transmission, transmission way, there can be divided into grade level and synthetical three.(a) : several levels of transmission ratio, can choose the fixed by gear. And can be divided into: gear axis of ordinary gear transmission and fixed gear planetary gear (part) of planetary gear transmission axis of rotation.b) stepless type transmission: ratio can be continuous variation within a certain range, commonly, mechanical and electric hydraulic type etc.(c) comprehensive type transmission by a class type, transmission and stepless type transmission, the ratio of the maximum and minimum values can be in between the scope for several section stepless change.2, press control can be divided into compulsory manipulation, transmission, automatic control and semi-automatic control 3 kinds.(a) mandatory manipulation of transmission by direct manipulation, change gear shift lever drivers.(b) automatic control type transmission ratio of choice and change: the shift is automatic. Drivers simply manipulate accelerated pedal, transmission can according to the engine speed and load control signal signal actuator, realize the transformation of gear.(c) semi-automatic control type transmission can be divided into two kinds: one kind is part of gear, automatic shift gears, manual (mandatory) shift, Another kind is selected by button in mining under gear clutch pedal or accelerated release pedal, the executing agency to shift. Transmission of maintenance1 transmission gears maintenanceTransmission gears are always changing speed, load, gear tooth surface by bluntThe impact of load, which struck gear tooth surface (especially) damage. Common injuries are:(1) gear transmission is worn gear under normal working conditions, shows the wear uniform angled tooth gear, long wear along the direction of the tooth should not exceed 30 percent longer, Tooth thickness should not exceed usd, Gear tooth surface area of not less than two-thirds, Running gear mesh clearance shall be commonly used, 0.15-0.26 mm to 0.8 mm limit, Gear engagement between 0.10-0.15 mm, should use limit for 0.60 mm. Available batches or soft metal rivalries. If more than clearance method for measuring the pairs, should be replaced.(2) gear teeth, broken tooth gear clearance is mainly due to fail to meet the requirements, gear meshing parts or work under great impact load. If you are not greater than 2mm edge of gear oil can smile ShiXiuafter-grinding continue to use, If the scope or have more than three pairs, should smile.(3) often mesh surface of the helical gear often wear face due. 10-0.30 mm, in order to ensure that the axial clearance, if tooth gear good operation within the wear, can repair tank, but the amount of grinding grinding should not exceed. 50.(4) often meshing gears shaft neck, needle roller bearing and wear into seat hole hole meshing gears seat with needle bearings and shaft neck with clearance should be 0.01 - three 0.08 mm, otherwise must be changed.2 the overhaul. Transmission shellGearbox shell is transmissions, to ensure the basis of each part of the transmission is correct position, work under load. Common injuries are:(1) the abrasion of shell bearing hole hole wear will destroy its bearing assembly relation with the bearing, the direct impact of input, output shaft transmission position relative to the hole. Bearing seat with 0-0.03 mm clearance shall be used for the maximum limit, should be replaced or 0.10 mm) shell or pile hole repair.(2) shell threaded holes repair note oil ROM plug hole, dumping screw hole threads connecting bolts damage and between shellThreaded hole, can take damage with screw repair.3 transmission shaft of maintenanceTransmission in the process of operation, each bearing the torsional moment of change, and bending moment, JianChi part is under pressure, impact and sliding friction etc. Various axial load of common injuries are:(1) the shaft neck and neck too worn wear axis gear axis will not only offset, and can bring the change gear clearance, when making noise transmission shaft neck. Also make coordination relationship with bearing damage, may cause ablation. So roller bearings in a place with no more than 0.02 axis wear mm needle bearing shaft neck wear with place, otherwise than 0.07 mm landscape change or chrome.(2) JianChi wear JianChi wear in stress and more serious side of the spline. JianChi with check, when more than 0.25 or and wear with more than usd keyway apprentice, gear engagement mm, combining with the gear with JianChi weeks, according to the mm apprentice woodruff key and shaft neck keyways apprentice to JianChi 0.08 mm over there when the keyway weeks, or should be repaired or replaced shaft.(3) transmission shaft bending thimble resist transmission shaft with maintenance on both ends of the roof, using pinhole batches of shaft radial micrometers, check the deviation should be less than 0.10 mm) pressure correction repair.4 synchronizer overhaulA. lock ring type inertial synchronizer ring maintenance: lock horns cone a about six degrees - 7 degrees, in use, cone Angle deformation ofrapid synchronous, and not be change in time.B. locking pin type inertial synchronizer: locking pin type synchronizer major damage for cone rim wear, when, cone-disk cone rim on the thread of groove depth 0.40 mm wear to 010mm deep, should be replaced. If the cone rim are scratching, face to face, but two turning machining, must not be more than 1mm should be replaced.变速器手动变速器是最常见的变速器，简称MT。

附录附录ADrive axle/differentialAll vehicles have some type of drive axle/differential assembly incorporated into the driveline. Whether it is front, rear or four wheel drive, differentials are necessary for the smooth application of engine power to the road.PowerflowThe drive axle must transmit power through a 90°angle. The flow of power in conventional front engine/rear wheel drive vehicles moves from the engine to the drive axle in approximately a straight line. However, at the drive axle, the power must be turned at right angles (from the line of the driveshaft) and directed to the drive wheels.This is accomplished by a pinion drive gear, which turns a circular ring gear. The ring gear is attached to a differential housing, containing a set of smaller gears that are splined to the inner end of each axle shaft. As the housing is rotated, the internal differential gears turn the axle shafts, which are also attached to the drive wheels.Fig 1 Drive axleRear-wheel driveRear-wheel-drive vehicles are mostly trucks, very large sedans and many sports car and coupe models. The typical rear wheel drive vehicle uses a front mounted engine and transmission assemblies with a driveshaft coupling the transmission to the rear drive axle. Drive in through the layout of the bridge, the bridge drive shaft arranged vertically in the same vertical plane, and not the drive axle shaft, respectively, in their own sub-actuator with a direct connection, but the actuator is located at the front or the back of the adjacent shaft of the two bridges is arranged in series. Vehicle before and after the two ends of the driving force of the drive axle, is the sub-actuator and the transmission through the middle of the bridge. The advantage is not only a reduction of the number of drive shaft, and raise the driving axle of the common parts of each other, and to simplify the structure, reduces the volume and quality.Fig 2 Rear-wheel-drive axleSome vehicles do not follow this typical example. Such as the older Porsche or Volkswagen vehicles which were rear engine, rear drive. These vehicles use a rear mounted transaxle with halfshafts connected to the drive wheels. Also, some vehicles were produced with a front engine, rear transaxle setup with a driveshaft connecting the engine to the transaxle, and halfshafts linking the transaxle to the drive wheels.Differential operationIn order to remove the wheel around in the kinematics due to the lack of co-ordination about the wheel diameter arising from a different or the same rolling radius of wheel travel required, inter-wheel motor vehicles are equipped with about differential, the latter to ensure that the car driver Bridge on both sides of the wheel when in range with a trip to the characteristics of rotating at different speeds to meet the requirements of the vehicle kinematics.Fig 3 Principle of differentialThe accompanying illustration has been provided to help understand how this occurs.1.The drive pinion, which is turned by the driveshaft, turns the ring gear.2.The ring gear, which is attached to the differential case, turns the case.3.The pinion shaft, located in a bore in the differential case, is at right angles to the axle shafts and turns with the case.4.The differential pinion (drive) gears are mounted on the pinion shaft and rotate with the shaft .5.Differential side gears (driven gears) are meshed with the pinion gears and turn with the differential housing and ring gear as a unit.6.The side gears are splined to the inner ends of the axle shafts and rotate the shafts as the housing turns.7.When both wheels have equal traction, the pinion gears do not rotate on the pinion shaft, since the input force of the pinion gears is divided equally between the two side gears.8.When it is necessary to turn a corner, the differential gearing becomes effective and allows the axle shafts to rotate at different speeds .Open-wheel differential on each general use the same amount of torque. To determine the size of the wheel torque to bear two factors: equipment and friction. In dry conditions, when a lot of friction, the wheel bearing torque by engine size and gear restrictions are hours in the friction (such as driving on ice), is restricted to a maximum torque, so that vehicles will not spin round. So even if the car can produce more torque, but also need to have sufficient traction to transfer torque to the ground. If you increase the throttle after the wheels slip, it will only make the wheels spin faster.Limited-slip and locking differential operationFig 5 Limited-slip differentialDifferential settlement of a car in the uneven road surface and steering wheel-driven speedat about the different requirements; but is followed by the existence of differential in theside car wheel skid can not be effective when the power transmission, that is, the wheel slipcan not produce the driving force, rather than spin the wheel and does not have enoughtorque. Good non-slip differential settlement of the car wheels skid on the side of the powertransmission when the issue, that is, locking differential, so that no longer serve a usefuldifferential right and left sides of the wheel can be the same torque.Limited-slip and locking differential operation can be divided into two major categories：(1) mandatory locking type in ordinary differential locking enforcement agencies toincrease, when the side of the wheel skid occurs, the driver can be electric, pneumatic ormechanical means to manipulate the locking body meshing sets of DIP Shell will be withthe axle differential lock into one, thus the temporary loss of differential role. Relatively simple structure in this way, but it must be operated by the driver, and good roads to stop locking and restore the role of differential.(2) self-locking differential installed in the oil viscosity or friction clutch coupling, when the side of the wheel skid occurs when both sides of the axle speed difference there, coupling or clutch friction resistance on the automatic, to make certain the other side of the wheel drive torque and the car continued to travel. When there is no speed difference on both sides of the wheel, the frictional resistance disappeared, the role of automatic restoration of differentials. More complicated structure in this way, but do not require drivers to operate. Has been increasingly applied in the car. About non-slip differential, not only used for the differential between the wheels, but also for all-wheel drive vehicle inter-axle differential/.Gear ratioThe drive axle of a vehicle is said to have a certain axle ratio. This number (usually a whole number and a decimal fraction) is actually a comparison of the number of gear teeth on the ring gear and the pinion gear. For example, a 4.11 rear means that theoretically, there are 4.11 teeth on the ring gear for each tooth on the pinion gear or, put another way, the driveshaft must turn 4.11 times to turn the wheels once. The role of the final drive is to reduce the speed from the drive shaft, thereby increasing the torque. Lord of the reduction ratio reducer, a driving force for car performance and fuel economy have a greater impact. In general, the more reduction ratio the greater the acceleration and climbing ability, and relatively poor fuel economy. However, if it is too large, it can not play the full power of the engine to achieve the proper speed. The main reduction ratio is more Smaller ，the speed is higher, fuel economy is better, but the acceleration and climbing ability will be poor.附录B驱动桥和差速器所有的汽车都装有不同类型的驱动桥和差速器来驱动汽车行驶。

附录 A 外文文献Farm Machinery Using & MaintenanceThe most important thing is the meshing mark and meshing backlash of the driven bevel gears and active bevel gears, the firmness adjustment of half axle gears and planetary gear in maintenance of the BJ2020S jeep driving axle . This is an important and difficult job ,because the rear axle and driven working under the large load and high speed. And the bear is alternating load. If the meshing mark is not conforming to requirements or the meshing backlash is not good, it will appear smooth transmission speed and noise, wear, or even broken tooth gear, which directly influences the car service life and various tasks when it is working. At the same time , lord and driven tapered gear meshing mark and the check assembly and adjustment became a complicated problem although automobile driving axle structure is not a very complicated but some people is not familiar with the principle on gear transmission. Based on years of teaching and practice in the maintenance work with the adjustment of BJ2020S jeep driving axle differential gears and bearings has some method and steps of the relevant views and comments about something.ⅠAdjustment of the axis gear differential planetary gear mesh clearanceHalf axle gears and planetary gear mesh clearance is adjusted by half axle gears and differential shell thickness between three different (0.5 mm, 1.0 mm, 0.2 mm) thrust washers . Because of the planetary gear differential between shell with the thrust washers, so it must be the half axle gears through the thrust washers (two half axle gears and add, subtract washers), and the gap of the planetary gear mesh. Then using pins will planetary gear axle fixed.ⅡAdjustment of differential backlashThis bearing clearance is adjusted by adding, subtracting differential bearings and differential between shell thickness (0.5 mm in four different, o. mm, 0.15 ram, 0.10 ram) to adjust the adjustment of the gasket. In the adjustment of the former ready right and left bridge between shell of gasket, installation fixed good follower bevel gears. Active bevel gears should not installed in accordance with the relevant provisions of the torque (40-60N, m) installed left and right with tapered bridge housing, active gear with long bar, or a screwdriver to turn down, or pry differential assembly, to check differential assemblybearings between differential to feel no axial clearance and rotate freely.ⅢActive bevel gears bearing clearance adjustmentIn active position of bevel gears can be determined by the basic, increase and decrease active bevel gears with active before bearings taper gear bearing thrust ring between four different thickness (0.10 mm, 0.15 ram, 0.25 mm mm) adjustment, 0.50 gasket to adjust, the flexible rotation, no axial and radial clearance.ⅣActive bevel gears and driven bevel gears clearance and meshing mark adjustment Domestic automobile gear for no modifier, assembling widely adopted, the first meshing mark check whether the meshing mark requirements, such as requirements, through the change of bevel gears, driven axial position to get to meet the requirements of meshing mark, the active bevel gears bearing and differential bearing clearance (pre-tightening degrees) basis, rub-up, driven bevel gears, initiative on 3-4 taper gear teeth are coated with thin layer opposite, oil (or face turns into oil), according to the requirements and differential assembly installed left, right, forward and backward bridge housing, then turn active bevel gears decomposition of left and right to bridge housing, driven gear tooth surface of conical whether imprint requirements. If meshing mark requirements, visible to the situation by outward, to the right or left, bevel gears, driven to adjust. When the meshing mark to tooth root cap, the main, small or client, the formula for the Lord: "the Lord, from (i.e., big into bevel gears into active driven gear), small (i.e. driven out from bevel gears removed from active gear)." When the Lord, driven gear cone of meshing mark complies with the standards and inspection, driven bevel gears, active bevel gears and clearance of bevel gears driven backlash should actively bevel gears in the radius of 45mm flanges on the circumference displacement measurement, the arc length) should be in (0.2-0.6 mm. If does not accord with a standard, can increase and decrease active bevel gears and bearings taper gear after the shim between left and right or mobile differential bearing adjustment gasket, driven to adjust the gap, so bevel gears, driven when the bevel gears has adjusted, adjust the marks are not destroyed, small volume, driven tapered gear meshing mark.ⅤDrive and differential assemblyWe can start assemble the drive and differential when the differential gears, driven gear, each bearing, tapered meshing mark adjustment is over. Based on the thickness of the gasket and the bolt torques, we should coated with rubber seal, assembled active bevelgears, mount differential assembly, then closed the bridge housing.附录 B 中文译文减速器和差速器的调整与装配在对BJ2020S吉普车后桥的维修中，最主要的就是减速器主、从动圆锥齿轮的啮合印痕及啮合间隙；差速器半轴齿轮、行星齿轮啮合间隙和各轴承松紧度的调整。

汽车差速器的发展史在火车和汽车出现之前，马车一直都是人们出行十分重要交通工具。

人们喜欢乘坐马车从容地穿过乡村的大道或古旧的城区街巷去拜访朋友。

追溯以往，我们已经没有办法知道是谁第一个发明了车轮子，谁又造出了第一辆带轮子的车辆。

虽然车轮技术在初期并不太理想，但是它的出现还是提高了人类搬运物品的速度，促进了人类的发展。

公元前2000年，有的部落开始用马来拉有轮子的车，这种车轮已经开始像圆形，而不是早期车轮那样以整个木头块做成的。

约公元前1世纪，罗马制车匠发明了四轮马车并逐渐加以改进，使得四轮马车可以以前轮为导向前进。

为了让四轮马车的性能更高，他们在车轮上镶嵌金边用来减少车轮与车体的摩擦。

此后这种用作长途运输的马拉车成为各国主要的运输车辆。

它的优点是运输量大和运行平稳，缺点是需要较为平坦的路面才能行驶。

随着用于四轮马车行驶的道路年久失修，人们又改用实用的两轮车，因为它可以在崎岖的地形条件能够行驶。

后来经过再次改进，但人们对四轮马车的速度始终不能满意，希望发明一种比马更有耐力和更强壮的动力机器，以使车轮能够转得更快。

几千年后，在英国和美国的一些地方，少数人开始试验用蒸汽做动力，以钢铁做道路。

蒸汽火车便这样出现了，它的使用大大缩短了人们远程旅行的时间。

不过由于铁轨铺设的限制，人们去大多数地方还只有依靠马车。

为了解决这个问题，寻找一种能够完全替代马车的物品，发明家们又开始忙碌了起来。

后来经过不懈努力，卡尔·本茨研发出了一种能够代替马车的，就是由钢铁制成的三轮汽车。

本茨发明的三轮汽车装载量只相当于两轮马车，并没有舒适的车箱可供乘客遮风挡雨，不能获得大家认可。

可金子早晚都会发光的，不久有人对三轮汽车进行了改造，将它变为了四个轮子，并且具有像马车一样的带窗箱子，还让它有了一个好听的名字“无马马车”。

在这种四轮汽车出现后，它与四轮马车最大不同的地方在于转弯的时候。

四轮马车在转弯的时候是控制马拖动改变前面两个轮子的前进方向，再由与两个前轮相连接的车箱拖动后轮进行转向运动。