US Patent 10183700 Vehicle lower part structure

A vehicle lower part structure includes a side frame, a floor crossmember, a rectangular tubular rocker, and a connection member. The connection member is provided downward of the floor crossmember in a vehicle up-down direction between the side frame and the rocker, is in surface contact with and joined to each of a lower wall portion of the floor crossmember and a vertical wall portion on an inner side of the rocker in the vehicle-width direction, is formed of a single part into a rectangular tubular member, and has a vehicle front-rear direction as an axial direction of the connection member.