| 摘要 |
PROBLEM TO BE SOLVED: To reduce weight and cost in a steel door, by using an extremely thin steel sheet as a surface material and a reverse surface material.SOLUTION: Among a surface material 12 and a reverse surface material 13 in an end part of a steel door, one surface material 12 bends its bending extension part in a double folding structure to the inside in the other angle-21 position, by bending in a position of an angle 20 of forming the door end surface 12a. The other face material 13 forms an angle 21 in common by assembling in an inside position of an end surface part 12b bent in the double folding structure by bending in the other angle-21 position. The end surface part 12b bent in the double folding structure and an end surface part 13a assembled in its inside position, are formed in 1/several number of a width dimension W of the end surface. A reinforcement material 30 also serving as level raising is arranged in a nonexistent void space of the two end surface parts 12b and 13a among the width dimension W of the end surface 12a. This reinforcement material 30 is integrated into a skeleton by welding, and executes fixation-processing by adhering as contact surface between the mutual end surface part bend in the double folding structure and end surface part assembled in its inside position. |
