歯車の空力音の放射機構 : 流れの把握と音の放射過程の一解釈

抄録

One specific feature of the aerodynamic sound produced at the face end region is that the radiation becomes weak by filling root spaces as equivalent as by shorten center distance. However, one can easily expect that such action make the air flow faster, and consequently make the sound louder. This paper tries to reveal the reason for such feature. At first, air flow induced by the pumping action of the gear pair was analyzed regarding series of root spaces as volume varying cavities which has channels to adjacent cavities as well as the exit/inlet at face ends. The numerical analysis was verified by the hot wire anemometer measurement. Next, from the obtained flow response, sound source is estimated to be a combination of symmetrically distributed simple sources. Taking the effect of either center distance or root filling into consideration, it has become clear that the simplified model can explain such feature rationally.