A rear subframe structure is provided with a rear subframe configured such that a front cross member, a rear cross member, a pair of left and right upper side members, and a pair of left and right lower side members are connected; and a vehicle-body mounting portion formed on each of both ends of the front cross member, and on each of rear ends of the upper side members. The rear subframe further includes a vertical-wall-shaped pillar portion held and fixed between a lateral portion of the front cross member in the vehicle width direction and the upper side member, and extending in the vehicle width direction. A lower portion of the pillar portion is connected to the lower side member, an upper-arm support portion is formed on an upper portion of the pillar portion, and a lower-arm support portion is formed on a lower portion of the pillar portion.

A hat member 1 includes a top-plate portion 13, first ridges 113, and two side walls 11. The two side walls have a middle hardness Dc of 300 HV or higher. Each of the two side walls 11 includes a softened portion L and a strength-transition portion T adjacent to the softened portion L. The softened portion L has a hardness Dn lower than the middle hardness Dc by at least 8% (DcDn0.08Dc). The strength-transition portion T extends 0.5 mm or longer from the softened portion L toward the first end of the side wall. The strength-transition portion T has a hardness Dt that transitionally changes within the range of 8% to 1% lower than the middle hardness Dc (0.92DcDt0.99Dc). The hat member 1 further includes two second ridges 114 and two flanges 14.

A structural member for automobiles to be disclosed includes a press formed product. The press formed product includes two vertical wall sections and a top plate section that joins the two vertical wall sections to each other. At least part of the top plate section is provided with a protruding section that is a steel sheet extending from the top plate section and so folded over against itself as to protrude. The protruding section protrudes from the top plate section toward the interior of the press formed product and extends along the longitudinal direction of the press formed product. With the thus configured structural member, a structural member for automobiles that has a good characteristic in a three-point bending test is provided.

A vehicle body rear part structure for a vehicle includes a side frame, a subframe disposed below the side frame, and a vehicle body frame member disposed on a middle side in the vehicle body front-rear direction with respect to the subframe. The vehicle body frame member includes: a vertical frame offset outwardly in the vehicle width direction with respect to the subframe; and a lateral frame extending inwardly in the vehicle width direction from the vertical frame. A connecting portion is provided on the subframe. The connecting portion includes: an inclined portion extending while being inclined outwardly in the vehicle width direction, to face the vertical frame; and a widening portion widening inwardly in the vehicle width direction up to a position where the connecting portion linearly extends in the vehicle body front-rear direction from the inclined portion, to face the lateral frame.

A reinforcement structure for protection of a vehicle power source, e.g. a battery pack or a fuel cell. The reinforcement structure extends in a first, a second and a third direction (D.sub.1, D.sub.2, D.sub.3) being perpendicular to each other, wherein an extension of the reinforcement structure is at least 5 times larger in the first and second directions than in the third direction. The reinforcement structure has a tapered shape as seen in a plane spanned by the first and second directions. The present disclosure also relates to a reinforcement unit, a vehicle power source arrangement and a vehicle utilizing such reinforcement structure.

Provided is an automobile member including a hat-shaped first member that has a first flange, a second flange, a first wall portion erected from the first flange, a second wall portion erected from the second flange, and a web connecting the first and second wall portions to each other; a second member that is spot-joined to the first and second flanges; a first joining plate that is joined to inner wall surfaces of the first wall portion and the second member; and a second joining plate that is joined to inner wall surfaces of the second wall portion and the second member.

A strengthening structure of a vehicle is provided herein and includes a base having cutouts. Relief members are disposed across the base and each include a cross section having twelve or fourteen corners, a distal end, and an open proximal end in communication with a corresponding cutout.

A strengthening structure of a vehicle is provided herein and includes a base having cutouts. Relief members are disposed across the base and each include a cross section having twelve or fourteen corners, a distal end, and an open proximal end in communication with a corresponding cutout.

A structural member for an automobile to be disclosed includes a press-formed product formed from one steel sheet and a reinforcing member fixed to the press-formed product. The press-formed product includes two vertical wall portions and a top plate portion linking the two vertical wall portions. The reinforcing member is a member which has an L-shaped cross section and includes a first plate-like portion and a second plate-like portion. The first plate-like portion is fixed to one of the vertical wall portions such that the second plate-like portion protrudes toward an outward direction from the vertical wall portion side along the top plate portion.

A vehicle includes a strengthening member having a cross section including twenty-eight corners. The cross section has twenty-eight sides arranged to create twenty internal angles and eight external angles.