外文翻譯(汽車差速器)(適用于畢業(yè)論文外文翻譯+中英文對照)

1、wfailure analysis of an automobile differential pinion shaftabstractdifferential is used to decrease the speed and to provide moment increase fortransmitting the movement coming from the engine to the wheels by turning itaccording to the suitable angle in vehicles and to provide that inner and outer

2、 wheelsturn differently. pinion gear and shaft at the entrance are manufactured as a single partwhereas they are in different forms according to automobile types. mirror gear whichwill work with this gear should become familiar before the assembly. in case of anybreakdown they should be changed as a

3、 pair. generally in these systems there arewear damages in gears. the gear inspected in this study has damage as a form of shaftfracture.in this study failure analysis of the differential pinion shaft is carried out. mechanicalcharacteristics of the material are obtained first. then the microstructu

4、re andchemical compositions are determined. some fractographic studies are carried out toasses 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 ofthe gearbo

5、x. directly driven final drives are used when the engine and transmissionunits are combined together to form an integral construction. indirectly driven finaldrives are used at the rear of the vehicle being either sprung and attached to the bodystructure or unsprung and incorporated in the rear-axle

6、 casing. the final-drive gearsare used in the transmission system for the following reasons 1:a to redirect the drive from the gearbox or propeller shaft through 90 andb to provide a permanent gear reduction between the engine and the drivingroad-wheels. in vehicles differential is the main part whi

7、ch transmits the movement comingfrom the engine to the wheels. on a smooth road the movement comes to both wheelsevenly. the inner wheel should turn less and the outer wheel should turn more to dothe turning without lateral slipping and being flung. differential which is generallyplaced in the middl

8、e part of the rear bridge consists of pinion gear mirror geardifferential box two axle gear and two pinion spider gears. a schematic illustration of a differential is given in fig. 1. the technical drawingof the fractured pinion shaft is also given in fig. 2. fig. 3 shows the photograph of thefractu

9、red pinion shaft and the fracture section is indicated. in differentials mirror and pinion gear are made to get used to each other duringmanufacturing and the same serial number is given. both of them are changed oncondition that there are any problems. in these systems the common damage is thewear

10、of gears 24. 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 andhas a passenger capacity of 15 people. maximum engine power is 90/4000 hp/rpmand maximum torque is 205/1600 nm/rpm. its transmission box has manu

11、al system 5forward 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 wbroken. various studies have been made to determine the type and possible reasons ofthe damage.these are: studies carried o

12、ut 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 ofsur

13、faces.fig. 1. schematic of the analysed differential.fig. 2. technical drawing of the analysed pinion shaft wfig. 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

14、various tests including hardnesstests and metallographic and scanning electron microscopy as well as thedetermination of chemical composition. all tests were carried out at roomtemperature.2.1. chemical and metallurgical analysischemical analysis of the fractured differential material was carried ou

15、t using aspectrometer. the chemical composition of the material is given in table 1. chemicalcomposition shows that the material is a low alloy carburising steel of the aisi 8620type.hardenability of this steel is very low because of low carbon proportion. thereforesurface area becomes hard and high

16、ly enduring and inner areas becomes tough byincreasing carbon proportion on the surface area with cementation operation. this isthe kind of steel which is generally used in mechanical parts subjected do torsion andbending. high resistance is obtained on the surface and high fatigue endurance valueca

17、n be obtained with compressive residual stress by making the surface harder 57. in which alloy elements distribute themselves in carbon steels depends primarilyon the compound- and carbide-forming tendencies of each element. nickel dissolvesin the a ferrite of the steel since it has less tendency to

18、 form carbides than iron. siliconcombines to a limited extent with the oxygen present in the steel to form nonmetallic winclusions but otherwise dissolves in the ferrite. most of the manganese added tocarbon steels dissolves in the ferrite. chromium which has a somewhat strongercarbide-forming tende

19、ncy than iron partitions between the ferrite and carbide phases.the distribution of chromium depends on the amount of carbon present and if otherstronger carbide-forming elements such as titanium and columbium are absent.tungsten and molybdenum combine with carbon to form carbides if there is suffic

20、ientcarbon present and if other stronger carbide-forming elements such as titanium andcolumbium are absent. manganese and nickel lower the eutectoid temperature 8. preliminary micro structural examination of the failed differential material isshown in fig. 5. it can be seen that the material has a m

21、ixed structure in which someferrite exist probably as a result of slow cooling and high si content. high si contentin this type of steel improves the heat treatment susceptibility as well as animprovement of yield strength and maximum stress without any reduction of ductility9. if the microstructure

22、 cannot be inverted to martensite by quenching a reductionof fatigue limit is observed.table 1chemical analysis of the pinion gear material wtfe 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 andfracture surfaces.fig. 5. micro structure of the material 200. there are area

23、s with carbon phase in fig. 5a. there is the transition boundary ofcarburisation in fig. 5b and c shows the matrix region without carburisation. asfar as it is seen in these photographs the piece was first carburised then thequenching operation was done and than tempered. this situation can be under

24、stoodfrom blind martensite plates. 2.2. hardness tests the hardness measurements are carried out by a mettest-ht type computerintegrated hardness tester. the load is 1471 n. the medium hardness value of theinterior regions is obtained as 43 hrc. micro hardness measurements have beenmade to determine

25、 the chance of hardness values along the cross-section because ofthe hardening of surface area due to carburisation. the results of vickers hardnessmeasurement under a load of 4.903 n are illustrated in table 2. 2.3. inspection of the fracture w the direct observations of the piece with fractured su

26、rfaces and sem analyses aregiven in this chapter. the crack started because of a possible problem in the bottom ofnotch caused the shaft to be broken completely. the crack started on the outer partafter some time it continued beyond the centre and there was only a little part left.and this part was

27、broken statically during sudden starting of the vehicle at the trafficlights. as a characteristic of the fatigue fracture there are two regions in the fracturedsurface. these are a smooth surface created by crack propagation and a rough surfacecreated by sudden fracture. these two regions can be see

28、n clearly for the entireproblem as in fig. 4. the fatigue crack propagation region covers more than 80 ofthe cross-section. table 2 micro hardness values distance from surface lm 50 100 200 400 center values hv 4903n 588 410 293 286 263 fig.fig. 6. sem image of the fracture surface showing the ducti

29、le shear. wfig. 7. sem image of the fracture surface showing the beach marks of the fatiguecrack propagation. shaft works under the effect of bending torsion and axial forces which affectrepeatedly depending on the usage place. there is a sharp fillet at level on thefractured section. for this reaso

30、n stress concentration factors of the area have beendetermined. kt 2.4 value for bending and tension and kt 1.9 value for torsionhave been acquired according to calculations. these are quite high values for areasexposed to combined loading. these observations and analysis show that the piece was bro

31、ken under theinfluence of torsion with low nominal stresses and medium stress concentration 10. the scanning electron microscopy shows that the fracture has taken place in aductile manner fig. 6. there are some shear lips in the crack propagation regionwhich is a glue of the plastic shear deformatio

32、ns. fig. 7 shows the beach marks of thefatigue crack propagation. the distance between any two lines is nearly 133 nm. 3. conclusions a failed differential pinion shaft is analysed in this study. the pinion shaft isproduced from aisi 8620 low carbon carburising steel which had a carburisingquenching

33、 and tempering heat treatment process. mechanical properties microstructural properties chemical compositions and fractographic analyses are carriedout to determine the possible fracture reasons of the component. as a conclusion thefollowing statements can be drawn: the fracture has taken place at a

34、 region having a high stress concentration by afatigue procedure under a combined bending torsion and axial stresses having highlyreversible nature. the crack of the fracture is initiated probably at a material defect region at thecritical location. the fracture is taken place in a ductile manner. p

35、ossible later failures may easily be prevented by reducing the stressconcentration at the critical location. w汽車差速器小齒輪軸的失效分析摘要差速器的作用是根據(jù)車輛合適的角度 通過將運(yùn)動(dòng)轉(zhuǎn)向 為運(yùn)動(dòng)傳輸減速或者提供瞬間加速 這個(gè)運(yùn)動(dòng)來自引擎 到車輪去 使內(nèi)外車輪轉(zhuǎn)動(dòng)不同。開口處的游星齒輪和輪軸是作為單一零件的，但是根據(jù)車輛型號有不同的形狀。和這個(gè)齒輪一起工作的鏡面齒輪應(yīng)該在組裝前就磨合好。 一旦發(fā)生故障， 它們應(yīng)該成對更換。一般來說， 在這些系統(tǒng)中齒輪都存在磨損損壞。本文中檢查的齒輪損

36、壞具體說是輪軸斷裂。本研究進(jìn)行了差速器小齒輪軸的失效分析。首先，取得材料的機(jī)械特點(diǎn)，然后確定其微觀結(jié)構(gòu)和化學(xué)成分，還要做一些顯微鏡觀察研究來評估其疲勞和破損狀況。關(guān)鍵詞：差速器 破損；動(dòng)力分配裝置；小齒輪軸簡介最終傳動(dòng)齒輪可能直接或間接地由齒輪箱的輸出齒輪驅(qū)動(dòng)。 當(dāng)引擎和傳輸設(shè)備結(jié)合在一起，形成統(tǒng)一結(jié)構(gòu)時(shí)，就需要使用直接驅(qū)動(dòng)的最終傳動(dòng)齒輪。間接驅(qū)動(dòng)最終傳動(dòng)齒輪或者借助一些裝置附在汽車后端，或者并入后橋殼。最終驅(qū)動(dòng)齒輪由于如下原因被使用在傳輸系統(tǒng)中：a為了使齒輪箱或者傳動(dòng)軸的動(dòng)力 90轉(zhuǎn)向b為了提供引擎和驅(qū)動(dòng)輪之間永久的齒輪減速。在汽車中，差速器是將運(yùn)動(dòng)從引擎?zhèn)鬏數(shù)杰囕喌闹饕考?。在平坦的道路?/p>

37、，運(yùn)動(dòng)會(huì)平均分配給兩個(gè)輪子。內(nèi)側(cè)車輪應(yīng)該程度小一些 外側(cè)車輪轉(zhuǎn)向程度應(yīng)該大一些 這樣轉(zhuǎn)彎才不會(huì)側(cè)滑。 差速器通常置于后橋中部， 由游星齒輪、鏡面齒輪、差速器箱、軸齒輪和兩個(gè)游星蜘蛛齒輪構(gòu)成。 圖表一是差速器的示意圖， 圖表二是斷裂的小齒輪軸的技術(shù)圖解，圖表三是斷裂的小齒輪軸的圖片，表示出了斷裂部分。在差速器里， 人們生產(chǎn)時(shí)將鏡面和流星齒輪制作得相互適應(yīng)，并且使用相同的序列號。出現(xiàn)問題的話，二者都要更換。在這些系統(tǒng)中，常見的損傷是齒輪磨損。本研究檢查了一輛小型巴士的差速器小齒輪軸。 該小型巴士是后軸驅(qū)動(dòng)的柴油汽車，可搭載 15 名乘客。發(fā)動(dòng)機(jī)最大功率是 ，最大扭轉(zhuǎn)力是 。傳動(dòng)箱里有手動(dòng)系統(tǒng) 5

38、個(gè)向前，一個(gè)向后。損傷是由巴士在交通燈出停止和啟動(dòng)引起的。在差速器中， 驅(qū)動(dòng)流星齒輪的輸入軸斷裂。人們做了各種各樣的研究來確定這種損傷的類型和可能的原因。 它們是: 確定輪軸材料的研究 確定微觀結(jié)構(gòu)的研究 與斷裂面相關(guān)的研究 圖四是斷裂表面和斷裂區(qū)域的近距離照片。 這個(gè)斷裂是將表面中心的圓形標(biāo)記齒輪取走形成的。 w圖1 進(jìn)行分析的差速器的圖解圖2 進(jìn)行分析的小齒輪軸的技術(shù)圖解圖 3 研究中進(jìn)行分析的完好小齒輪軸的圖片圖 4 失效輪軸的照片 w實(shí)驗(yàn)步驟從輪軸中取得的樣本要接受各種各樣的測試，包括硬度測試，金相和掃描電子顯微鏡以及化學(xué)成分的確定。左右測試均在室溫下進(jìn)行。化學(xué)和冶金分析 斷裂差速器材料的化學(xué)分析是使用光譜儀完成的。該材料的化學(xué)成分如表一所示?；瘜W(xué)成分顯示該材料是美國鋼鐵協(xié)會(huì) 8620 型的一種低合金碳化鋼。這種鋼的淬硬性很低，因?yàn)樘己勘壤^低。因而，需要通過滲碳處理增加表面區(qū)域的碳比例，使表面區(qū)域變得堅(jiān)硬，非常耐用，內(nèi)部區(qū)域變得堅(jiān)韌。這種鋼一般用在需要扭轉(zhuǎn)和彎曲的機(jī)械部件中。通過使表面變硬，用殘余應(yīng)力使表面獲得高阻力性，獲得高疲勞承受值。 合金元素怎樣摻入碳鋼主要取決于每種元素的化合傾向和形成碳化物的傾向。鎳溶解于鋼的鐵酸鹽，因?yàn)樗辱F更不容易形成碳化物。硅與鋼中的氧在一定程度上結(jié)合形成非金屬內(nèi)含物，不然的話則溶于鐵酸鹽。鉻比鐵更容易形成碳化物一些，會(huì)