汽车差速器英文.doc

Engineering Failure Analysis 13 (2006) 1422–1428  /locate/engfailanal  Failure analysis of an automobile di?erential pinion shaft H. Bayrakceken * Afyon Kocatepe University, Technical Education Faculty, 03200 Afyon, Turkey Received 8 July 2005; accepted 14 July 2005 Available online 2 September 2005 Abstract Di?erential 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 di?erently. Pinion gear and shaft at the entrance are manufactured as a single part whereas they are in di?erent 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 di?erential pinion shaft is carried out. Mechanical characteristics of the material are obtained ?rst. Then, the microstructure and chemical compositions are determined. Some fractographic studies are carried out to asses the fatigue and fracture conditions. 2005 Elsevier Ltd. All rights reserved. Keywords: Di?erential; Fracture; Power transfer; Pinion shaft 1. Introduction The ?nal-drive gears may be directly or indirectly driven from the output gearing of the gearbox. Di- rectly driven ?nal drives are used when the engine and transmission units are combined together to form an integral construction. Indirectly driven ?nal 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 ?nal-drive gears are used in the transmission system for the following reasons [1]: (a) to redirect the drive from the gearbox or propeller sha