歯車用高強度鋼材の接触・曲げ複合疲労試験

（歯車損傷モードの再現）

抄録

Many high strength steels for gear materials have been launched in these days. Conventional material tests; e.g., pulsator test for tooth root bending strength and twin-disc tests for rolling-sliding contact strength, might not accurately evaluate their strength in gear teeth. It is because a failure mode which frequently appears on gear teeth made of a high strength steel is not so simple as a breakage and pitting, but is a combination of these two modes. This failure mode could be simulated with contact-bending-fatigue (CBF) tests in which a test piece is subject to a bending stress similarly in the rotary-bending-fatigue tests and a contact pressure similarly in twin-disc tests. The present paper describes the concept of the CBF test and its possibilities for evaluating high strength gear materials.