| 摘要 |
PURPOSE:To form a lightweight and highly flexurally close-sectional structural member by a method wherein low density foaming agent is poured and filled through a hole bored at the practically central part of each hollow plate-shaped member and high density foaming agent is poured and filled through holes at the practically peripheral edge part of said hollow plate-shaped member. CONSTITUTION:In the floor structure 1 of an automobile, an inlet port 4 is provided at the practically central part 3 of each hollow plate-shaped member 2 and inlet ports 6 are provided at the practically peripheral edge part 5 of said hollow plate-shaped member so as to pour and fill low density foaming agent 7 through the inlet port 4 and, after that, pour and fill high density foaming agent 8 through the inlet ports 6. When the foaming agents 7 and 8 solidify, the cross-section of the member 2 has a constitution consisting of an nearly circular central part made of the previously poured and filled low density foaming agent 7 surrounded by the subsequently poured and filled high density foaming agent 8. The floor structure 1, which is made by integrating a layer having the above-mentioned constitution with an upper plate member 9 and a lower plate member 10 has efficiently improved flexural rigidity due to its high rigidity at its peripheral edge part and is comparatively light in weight as a whole due to its lightweight central part, which does not give much effect to flexural rigidity. |
