A different material joining structure has: a first panel made of a first metal material; a second panel made of a second metal material that has a higher conductivity than that of the first panel, is different from the first metal material, and at least a part of which faces the first panel; and a rivet for joining the first panel and the second panel, wherein the rivet is made of the first material, and includes a head portion that is embedded in the second panel in a non-penetrating manner and a bottom portion that abuts on the first panel, and wherein a nugget portion as a joint portion is disposed between the first panel and the bottom portion, the nugget portion being formed by resistance welding the rivet to the first portion with the rivet disposed between the first panel and the second panel.

A different material joining structure has: a first panel made of a first metal material; a second panel made of a second metal material that has a higher conductivity than that of the first panel, is different from the first metal material, and at least a part of which faces the first panel; and a rivet for joining the first panel and the second panel, wherein the rivet is made of the first material, and includes a head portion that is embedded in the second panel in a non-penetrating manner and a bottom portion that abuts on the first panel, and wherein a nugget portion as a joint portion is disposed between the first panel and the bottom portion, the nugget portion being formed by resistance welding the rivet to the first portion with the rivet disposed between the first panel and the second panel.

The present invention is provided with a roof side rail, a side outer panel that is formed of a dissimilar metal material having a higher electrical conductivity than the roof side rail, and a metal layer that is formed of the same metal material as the roof side rail and is disposed between the roof side rail and the side outer panel. Forming a nugget, which is a joint portion, between the roof side rail and the metal layer by carrying out resistance welding with the metal coating disposed between the roof side rail and the side outer panel makes it possible to accommodate the enhanced strength of an iron member and to render prepared hole processing unnecessary.

The present invention is provided with a roof side rail, a side outer panel that is formed of a dissimilar metal material having a higher electrical conductivity than the roof side rail, and a metal layer that is formed of the same metal material as the roof side rail and is disposed between the roof side rail and the side outer panel. Forming a nugget, which is a joint portion, between the roof side rail and the metal layer by carrying out resistance welding with the metal coating disposed between the roof side rail and the side outer panel makes it possible to accommodate the enhanced strength of an iron member and to render prepared hole processing unnecessary.

A vehicle body side structure 1 includes a roof side rail 2, a center pillar 3, a first joint portion 5, a second joint portion 6, and a third joint portion 7. The first joint portion 5 joins a roof side rail outer 22 and a roof side rail inner at a corner portion 10 formed by the roof side rail 2 and the center pillar 3. The second joint portion 6 joins a center pillar outer 32 and a roof side rail inner at the corner portion 10. The third joint portion 7 joins a center pillar inner and the center pillar outer 32 at the corner portion 10. The first joint portion 5, the second joint portion 6, and the third joint portion 7 are continuously provided from an upper side to a lower side.

A vehicle body side structure 1 includes a roof side rail 2, a center pillar 3, a first joint portion 5, a second joint portion 6, and a third joint portion 7. The first joint portion 5 joins a roof side rail outer 22 and a roof side rail inner at a corner portion 10 formed by the roof side rail 2 and the center pillar 3. The second joint portion 6 joins a center pillar outer 32 and a roof side rail inner at the corner portion 10. The third joint portion 7 joins a center pillar inner and the center pillar outer 32 at the corner portion 10. The first joint portion 5, the second joint portion 6, and the third joint portion 7 are continuously provided from an upper side to a lower side.

A vehicle body structure includes: a first frame that is formed of a first material and has a closed cross section; and a second frame that is formed of a second material and has a closed cross section. The first frame and the second frame are aligned with each other in a vehicle longitudinal direction. The second frame has higher tensile strength and is lighter than the first frame. In a front cross-sectional view of the vehicle, a second center associated with the second frame is located on an outer side in a vehicle width direction from a first center associated with the first frame with respect to vehicle center.

A vehicle body structure includes: a first frame that is formed of a first material and has a closed cross section; and a second frame that is formed of a second material and has a closed cross section. The first frame and the second frame are aligned with each other in a vehicle longitudinal direction. The second frame has higher tensile strength and is lighter than the first frame. In a front cross-sectional view of the vehicle, a second center associated with the second frame is located on an outer side in a vehicle width direction from a first center associated with the first frame with respect to vehicle center.

Provided is a method for assembling a vehicle roof structure capable of suppressing occurrence of distortion of a roof panel. The method includes an application portion forming step, a roof panel disposing step, a roof panel mechanically fixing step, and a mastic adhesive curing step. In the application portion forming step, a plurality of application portions is formed such that among the plurality of application portions, a central application portion disposed at a center of a cross member in a vehicle width direction has a length that is shorter than a length of an end-side application portion disposed on opposite sides of the center in the vehicle width direction.

Provided is a method for assembling a vehicle roof structure capable of suppressing occurrence of distortion of a roof panel. The method includes an application portion forming step, a roof panel disposing step, a roof panel mechanically fixing step, and a mastic adhesive curing step. In the application portion forming step, a plurality of application portions is formed such that among the plurality of application portions, a central application portion disposed at a center of a cross member in a vehicle width direction has a length that is shorter than a length of an end-side application portion disposed on opposite sides of the center in the vehicle width direction.