Vehicle body structure

A vehicle body structure in which left and right side frames made of a steel plate are located on both sides in a vehicle width direction, wherein

• each of the left and right side frames includes a distal end on an on an external force acting side that receives a collision load in a vehicle longitudinal direction acting from outside of a vehicle, and a proximal end on an opposite side of the distal end,
• the left and right side frames are provided with a plurality of fragile portions on left and right sides, which are formed as fragile regions in which a hardness of the steel plate is lower than in other portions of the left and right side frames,
• when the left and right side frames are viewed from above, the plurality of fragile portions on the left and right sides are arranged in a staggered pattern in a vehicle longitudinal direction,
• the plurality of fragile portions on the left and right sides comprise at least left and right first fragile portions located at the distal ends, and left and right second fragile portions located on sides of the proximal ends apart from the left and right first fragile portions,
• an area of each of the left and right first fragile portions is set to be larger than areas of the left and right second fragile portions,
• the left and right rear side frames are each formed from at least two divided bodies divided in a vertical direction,
• flanges provided at both edges of the lower divided body in the vehicle width direction and flanges provided at both edges of the upper divided body in the vehicle width direction are overlaid in the vertical direction and welded at a plurality of weld points arranged at an interval in the vehicle longitudinal direction,
• the left and right rear side frames are each formed into a closed section by the lower divided body and the upper divided body,
• the left and right first fragile portions are located in the left and right rear side frames close to outside in the vehicle width direction, and are each formed from a lower fragile portion provided in the lower divided body and an upper fragile portion provided in the upper divided body,
• a line passing through a center of each of the left and right rear side frames in a widthwise direction and extending in a vehicle vertical direction is defined as a center line in the widthwise direction, and
• the lower fragile portion and the upper fragile portion are provided from a distal end of the flange outside in the vehicle width direction to a position inside in the vehicle width direction with respect to the center line in the widthwise direction.

A vehicle body structure in which left and right side frames are located on both sides in a vehicle width direction, wherein

• each of the left and right side frames includes an end on an on an external force acting side that receives a collision load in a vehicle longitudinal direction acting from outside of a vehicle, and an end on an opposite side of the end on the external force acting side,
• the left and right side frames are provided with a plurality of fragile portions on left and right sides,
• the plurality of fragile portions on the left and right sides comprise at least left and right first fragile portions located at the ends on the external force acting side, and left and right second fragile portions located on sides of the ends on the opposite side apart from the left and right first fragile portions,
• an area of each of the left and right first fragile portions is set to be larger than each of areas of the left and right second fragile portions,
• the left and right side frames are each formed into a closed section with a bottom surface viewed from a longitudinal direction,
• the left and right bottom surfaces include left and right slant surfaces slanting upward from the ends on the external force acting side toward the ends on the opposite side, and
• the left and right second fragile portions are located within a range including the slant surfaces in the longitudinal direction of the left and right side frames and only on an upper side of the left and right side frames.