Turbine rotor and turbocharger having the turbine rotor

Abstract

A turbine rotor comprising: a turbine wheelobtainable by precision casting of titanium aluminide, including a hubextending along a rotational center of the turbine wheel, and a plurality of impellersarranged along a circumferential direction around an outer circumference of the hub, and having a web-like scallopformed by making a cutout between adjacent impellers among the plurality of the impellers; and a rotor shaftextending along the rotational center line C-C of the turbine wheel on a back side of the hub of the turbine wheel; wherein the turbine wheel has a balance cut portionarranged along the circumferential direction of the rotational turbine wheel on the back side of the hub of the turbine wheel, wherein an area of the balance correcting part arranged in the circumferential direction is placed so that a balance cut minimum diameter BCmin is larger than a maximum diameter of the rotor shaft on the wheel mounting side, and that a balance cut maximum diameter BCmax is smaller than a scallop diameter S of the turbine wheel, and that a thickness t from the back side of the turbine wheel to a surface of the hub satisfies 1.75t≧w, where w is a width in a radial direction of the area arranged in the circumferential direction (i.e. balance cut).