Spiral Bevel Gear and Pinion Forging Development Program
Final rept. 20 May 1970-29 Feb 1972
TRW EQUIPMENT LABS CLEVELAND OH MATERIALS TECHNOLOGY DEPT
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Spiral bevel gear sets used in the main power transmission train of the CH-47 helicopter were produced from forgings with the gear teeth precision preformed into the forging cone face. The total manufacturing process, including forging, die design and die fabrication was studied, and developments made as required to demonstrate a new approach to making these gears. A number of development cycles were required to produce the desired results and an original metrology system had to be organized to direct the development of the proper geometry in the forged teeth. After the planned process development was completed, gears were finished from the precision forgings so that the preformed teeth were finish ground using the same operations as the equivalent cut gear. Metallurgical analysis confirmed that favorable grain flow in the tooth sections was achieved and case and core properties were to specification. Limited single tooth fatigue testing demonstrated that the forged teeth were at least equivalent to cut teeth.
- Fabrication Metallurgy
- Machinery and Tools