齿轮精密锻造技术的发展

研究和试验了圆柱直齿轮、圆柱斜齿轮和同步齿轮等 3种汽车用齿轮。制造工艺采用温锻加冷处理 ,用有限元模拟来分析锻造过程和设计模具 ,从而保证齿轮的精度。经过 3年的研究 ,已掌握其基本技术 ,下一步将进行工厂现场试验

Development of the net-shape forging technology of gears

This paper describes some aspects of the development of a commercially viable forming route for the manufacture of net\|shape gear forms.The critical features of the manufacturing method are that it should be low cost and have high productivity.Thus the development has been based on single acting presses,with only one ram and a high stroking rate.The aim of the work is to produce net\|shape only on the gear form as it is considered that the most economic method for producing other features on conventional gears is by near net\|shape forming followed by machining.The work is sponsored by EPSRC(UK) and seven UK industrial partners including gear users,forgers,die manufacturers and steel makers.The project concentrated on automotive gearbox gears.The size and geometry of this type of gear largely precludes cold forging as the sole production process as press capacity and tool stresses would be too great.The forming sequence chosen is,warm forging,to obtain a near\|net shape envelope,followed by a cold sizing operation.The crucial factor enabling gear teeth to be formed net\|shape is the cold finishing die.This has been designed using high resolution FE analysis containing detailed information of elastic distortions in both die and workpiece. It is demonstrated that satisfactory cold finishing dies can be designed and that gear teeth to ISO 5 standard can be formed.The complexity of the cold finishing die and the ultra high accuracy to which it must be made taxes,the ability of tool making companies and is a subject for immediate development if the gear forming process is to be taken up commercialy.Another issue to be addressed is the development of an appropriate measuring technique for formed gears.