外文中英文翻译(汽车差速器).doc

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 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 shaft 1. Introduction The 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