DEVELOPMENT OF A RESONANCE TYPE GEAR FATIGUE TESTER.

A resonance type gear fatigue tester has been developed to evaluate tooth root fatigue strengths rapidly and efficiently. The tester operates on the resonance condition. One of a pair of test gears is held stationary to the tester bed and the other, fastened to the vibratory shaft, is oscillated against the stationary gear. The torsional vibration of the vibratory shaft is excited by the rotating eccentric on the end of the lever arm fixed to the shaft. Torque amplitude is controlled by varying the rotational speed of the eccentric, which is rotated with a 1. 5 kw induction motor driven by a frequency converter. If the test frequency is slightly below the natural frequency of the vibrating system containing the test gears, sudden overloading occurs with the natural frequency drop due to slip on the tooth face and so on. To prevent overloading, a tester is designed so that the frequency can be set above the natural frequency. The test frequency range of the tester is 1000-3000 cpm and the torque capacity is 1200 N multiplied by (times) m.