Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 03, 2023 - September 06, 2023
The authors conducted operational tests on spur gears injection-molded with a composite resin of polyacetal and cellulose nanofibril (POM/CNF) and investigated the bulk temperature, noise, and fatigue life of test gears. As a result, several findings were obtained regarding the usefulness of CNF as a reinforcing material for plastic gears. However, there are still many unknowns about the effect of CNF. This paper investigates the mechanism of fracture of POM/CNF gears. Test gears were fabricated from POM/CNF composites. Endurance tests were conducted without lubrication. The test gears were operated at constant transmitted torque and rotational speed until failure. The results indicated that adding CNF improved fatigue life and caused less wear on the tooth face. Therefore, the fatigue life of POM/CNF gears is not affected by heat by tooth friction and wear. In addition, the addition of CNF deteriorates flowability during injection molding and forms many voids, so the cracks formed at the tooth root due to fatigue propagates toward the voids, and then test gears are breakage.
