| 主权项 |
1. A subframe structure for a vehicle, the subframe structure being arranged at a front of the vehicle and fixed to or floatably supported by a vehicle-body member, said subframe structure comprising:
a front subframe made of steel, the front subframe comprising a front cross member extending along a width direction of the vehicle and a pair of left and right side members extending from the front cross member toward a rear of the vehicle, each of the left and right side members comprising a front section, an intermediate section and a rear section; and a rear subframe made of light metal comprising aluminum or an aluminum alloy, the rear subframe comprising a pair of left and right rear side sections and a rear cross section connecting the left and right rear side sections to each other, wherein: the left and right rear side sections of the rear subframe overlie and substantially completely cover the left and right rear sections of the left and right side members of the front subframe, respectively, in a substantially stacked configuration, and the front subframe and the rear subframe are joined together by friction stir welding in a state in which the rear subframe is superposed on the front subframe, wherein: the front subframe comprises a press-formed body formed by pressing, the rear subframe comprises a die-cast body formed by die-casting, and the rear sections of the left and right side members of the front subframe are provided with respective extending side sections extending toward a rear of the vehicle, the extending side sections of the front subframe and the left and right rear side sections of the rear subframe are provided with respective flange sections, an outer portion of the flange section of each of the left and right rear side sections includes a protruding lateral edge section having a concave groove formed therein and recessed toward a top side, the protruding lateral edge sections are formed in a manner so as to protrude outwardly beyond adjacent portions of the left and right side members along the width direction of the vehicle, respectively, and then the protruding lateral edge sections extend vertically downwardly beyond upper surfaces of said adjacent portions of the left and right side members, and the left and right rear side sections of the rear subframe are superposed on upper surfaces of the extending side sections of the front subframe to join the flange sections together. |
