外文翻譯---汽車差速器小齒輪軸的失效分析

1、Failure analysis of an automobile differential pinion shaft Abstract Differential is used to decrease the speed and to provide moment increase for transmitting the movement coming from the engine to the wheels by turning

2、 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 ac

3、cording 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

4、 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 o

5、btained 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;

6、 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 tog

7、ether 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

8、 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 t

9、he 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 wh

10、eel 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 gea

11、r, 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

12、. 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 i

13、s 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 inspec

14、ted. 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 sys

15、tem (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 Fig. 3. The picture of the undamaged differ

16、ential pinion analysed in the studyFig. 4. Photographs of failed shaft2. Experimental procedure Specimens extracted from the shaft were subjected to various tests including hardness tests and metallographic and scanning

17、electron microscopy as well as the determination of chemical composition. All tests were carried out at room temperature.2.1. Chemical and metallurgical analysis Chemical analysis of the fractured differential material

18、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 t

19、his 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 opera

20、tion. 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

21、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 t