Automotive drivetrain gears are required to be strengthened in order to meet the needs of higher engine power and weight saving. To cope with this requirement, new technology for strengthening gears has been developed which combines carburizing with induction hardening. New technology, carburizing and induction hardening, has significantly improved impact fatigue strength and spalling strength, which are critical strength properties to differential gears. The new process made it possible to apply a 2-pinion type differential unit as an alternative to a 4-pinion type one which had been necessary to reduce the load distribution to the pinions and to ensure durability and reliability, resulting in unit weight reduction by 15 % and unit cost reduction by 40 % by reduction in number of parts. The key point is to ensure fine austenite grain size by means of optimizing induction hardening conditions and steel compositions. A new process, which Mazda calls carburizing and induction hardening, has made it possible to obtain impact fatigue strength and spalling strength far higher than that obtainable by the conventional carburizing.
Development of Manufacturing Technology for High-Strength Differential Gears
Fertigungstechnologie für hochfeste Differential-Zahnräder
Review of Automotive Engineering (JSAE) ; 25 , 2 ; 211-217
2004
7 Seiten, 16 Bilder, 2 Tabellen, 4 Quellen
Article (Journal)
English
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