Shin Morishita

This study was intended to reduce the gear noise, and for this purpose, the visualization of strain distribution in gear teeth was accomplished by means of the combination of photo-elasticity technique and a high-speed camera. Prior to finding the mechanical factor of the gear noise, the dynamic strain distribution in gear teeth under lubricated condition was studied by the photo-elasticity technique in this paper. Gear teeth under operation are exposed to severe and complex condition of high contact pressure in meshing area and slipping surface with different curvature. For that reason, serious problems might have been taken place on the noise, vibration and lubrication during operation. Regarding to the gear noise, there have been appeared lots of researches, and a variety of effects on the gear noise have been put together systematically. However, the relationship between the gear noise and the condition of meshing has not been clarified yet. In order to understand the mechanism at the meshing point, it is important to know the dynamic strain distribution in gear teeth during operation. In this experiment, the gears were made of transparent epoxy resin. The photo-elasticity technique was applied for visualization of strain distribution around meshing area of gears, and the fringe patterns caused by strain distribution were recorded by a high-speed camera. As a result, the change of the strain distribution by number of meshing was observed, and the effect of slipping contact and grease became apparent from the strain distribution.

This paper proposes a space vector modulation of a high frequency AC-inked matrix converter which is applied to an electric transformer system. The one of problem of a commercial frequency transformer is bulky and heavy. In order to resolve this problem, we propose to use a high frequency transformer driven by three-phase to single phase matrix converter. In this paper, the virtual indirect control method with a space vector modulation is applied to the primary and secondary side matrix converter. Particularly, the control of the secondary side matrix converter should be considered because the input is rectangle which has multiple levels of voltage. The fundamental operation of the proposed system is demonstrated by experiment and simulation with 1-kW prototype. Besides, the volume and weight of the proposed system are compared with that of the commercial frequency transformer system at 50 kVA. As the result, it is confirmed that the volume and weight of the proposed system are reduced to 15% and 5%, respectively in comparison with that of the transformer system.