A Fundamental Study of the Surface Durability of Medium-Hardness Gears : Effects of Combination of Hardness and Surface Roughness

The effects of the combination of tooth flank hardness and tooth surface roughness on the surface durability of medium-hardness gears are investigated using a disk machine. The meaning of the difference in hardness between a pair of gears is discussed. In the case where the surface roughnesses differ between contact surfaces with the same initial hardness, severe wear and pitting occur on the smooth surface because the asperities on the rough surface are highly hardeneddue to the repetition of contact. Therefore, it is necessary that the initial hardness of the smooth surface is higher than that of the rough surface in a combination of different sufface roughnesses. This means that the hardness combination between a pair of gears should be determined in consideration of the final condition of the finished tooth surfaces of the gears

Study on high efficiency milling of steam turbine blade

In response to global environmental issues, higher efficiency and improved operational reliability are increasingly being requested for steam turbines, essential equipment for thermal power generation. Its material is stainless steel, which is difficult to cut because of high work-hardening trend and high resistance to heat. As its complex shape and high accuracy requirement, conventional methods such as using a ball end mill have obstacles of achieve a high accuracy coexist with high efficiency. The main objectives of this study are to propose a new method called Linear Interpolation Milling(LIM) using a taper end mill and verify its validity both in theory and practice.1st International Conference on Renewable Energy Research and Applications, ICRERA 2012; Nagasaki; Japan; 11 November 2012 ～ 14 November 201