Development of micro gear tester on failure and strength (design and fabrication of the tester and evaluation of metallic glass micro gears)

A testing instrument to evaluate the performance of micro gear with diameter below 1 mm has been developed. For micro gear, gear assembly condition and rotational accuracy of gear shaft have large influence on gear performance compared with normal size gear and therefore they must be adjusted appropriately. However, due to the size of gear being too small, the conventional type of gear support method and measurement and adjustment method of gear assembly condition cannot be applied. In this research, one sided support structure of large size shaft and bearing with preload is proposed and it contributes to the reduction of the radial rotational errors and high support stiffness. The measurement and adjustment method of gear assembly condition have been described and verified, using XY stage, laser displacement sensor and fitting algorithm of theoretical form into measured form. The result of fundamental gear test using developed micro gear tester indicated that metallic glass micro gear shows peeled surface across the tooth area with considerably less significant gear tooth failure.