| 摘要 |
PURPOSE:To prevent generation of stress concentration on the boundary between the neck portion of a turbine wheel and a coupling shaft by constructing a turbine shaft with a shaft body and an annular body and forming taperingly the end portion of the shaft body facing an escape space accommodating the neck portion of the turbine wheel. CONSTITUTION:A turbine wheel 4 is provided with a neck portion 12 projecting by changing the diameter continuously from the back of the wheel and a coupling shaft 13 extending from a small bore portion of the neck portion 12, and the entire body is integrally formed by ceramic. In this case, a turbine shaft 10 is made of metal and constructed by a shaft body 14 fit to the outer circumference of the coupling shaft 13 and an annular body 15 fit to the outer circumference of the inner end portion of the shaft body 14 and making contact with the back of the turbine wheel 4. And an escape space 16 accommodating the neck portion 12 is formed inside the annular body 15 and the inner end portion 14a of the shaft body 14 facing the escape space 16 is formed taperingly by placing its peak on the boundary between the neck portion 12 and the coupling shaft 13. By this, generation of stress on the boundary between the neck portion 12 and the coupling shaft 13 can be prevented. |
