Door beam

1. A door beam arranged between an inner panel and an outer panel that form a door of a vehicle, the door beam reinforcing the inner panel and the outer panel, the door beam comprising:

an upper inner flange arranged on the inner panel side;

a lower inner flange arranged on the inner panel side and below the upper inner flange;

an outer flange arranged on the outer panel side;

an upper rib that couples the upper inner flange to the outer flange; and

a lower rib that couples the lower inner flange to the outer flange, wherein

a thickness of the outer flange is larger than a thickness of the upper inner flange and a thickness of the lower inner flange,

a thickness of the upper rib becomes gradually larger from the outer flange toward the upper inner flange,

a thickness of the lower rib becomes gradually larger from the outer flange toward the lower inner flange,

the upper inner flange includes:

an upper outward-protruding portion having a shape that protrudes upward from the upper rib in a vertical direction, and

an upper inward-protruding portion having a shape that protrudes downward from the upper rib in the vertical direction,

the lower inner flange includes:

a lower outward-protruding portion having a shape that protrudes downward from the lower rib in the vertical direction, and

a lower inward-protruding portion having a shape that protrudes upward from the lower rib in the vertical direction,

a length of the upper outward-protruding portion in the vertical direction is equal to or longer than a length of the upper inward-protruding portion in the vertical direction, and

a length of the lower outward-protruding portion in the vertical direction is equal to or longer than a length of the lower inward-protruding portion in the vertical direction.

2. The door beam according to claim 1 , wherein

the upper rib includes:

an upper outer surface formed on an upper side in a vertical direction; and

an upper inner surface formed on a lower side in the vertical direction,

the lower rib includes:

a lower outer surface formed on the lower side in the vertical direction, and

a lower inner surface formed on the upper side in the vertical direction,

an angle formed by the upper inner flange and one of the upper outer surface and the upper inner surface is an obtuse angle, and

an angle formed by the lower inner flange and one of the lower outer surface and the lower inner surface is an obtuse angle.

3. A door beam arranged between an inner panel and an outer panel that form a door of a vehicle, the door beam reinforcing the inner panel and the outer panel, the door beam comprising:

an upper inner flange arranged on the inner panel side;

a lower inner flange arranged on the inner panel side and below the upper inner flange;

an outer flange arranged on the outer panel side;

an upper rib that couples the upper inner flange to the outer flange; and

a lower rib that couples the lower inner flange to the outer flange, wherein

a thickness of the outer flange is larger than a thickness of the upper inner flange and a thickness of the lower inner flange,

a thickness of the upper rib becomes gradually larger from the outer flange toward the upper inner flange,

a thickness of the lower rib becomes gradually larger from the outer flange toward the lower inner flange,

the upper rib includes:

an upper outer surface formed on an upper side in a vertical direction, and

an upper inner surface formed on a lower side in the vertical direction,

the lower rib includes:

a lower outer surface formed on the lower side in the vertical direction, and

a lower inner surface formed on the upper side in the vertical direction,

an angle formed by the upper inner flange and the upper outer surface is an obtuse angle,

an angle formed by the lower inner flange and the lower outer surface is an obtuse angle, and

the upper inner surface and the lower inner surface are orthogonal to the outer flange.

4. The door beam according to claim 3 , wherein

a ratio of a distance between the upper inner surface and the lower inner surface to a distance between outer surfaces of the upper and lower inner flanges and an outer surface of the outer flange is equal to or higher than 0.7.

5. The door beam according to claim 1 , wherein

the upper inner flange, the lower inner flange, the outer flange, the upper rib, and the lower rib are made of aluminum or an aluminum alloy.

6. The door beam according to claim 1 , wherein

the thickness of the upper inner flange, the thickness of the lower inner flange, the thickness of the outer flange, the thickness of the upper rib, and the thickness of the lower rib are uniform in a longitudinal direction orthogonal to both a direction that connects the upper inner flange and the outer flange and a vertical direction.

7. A door beam arranged between an inner panel and an outer panel that form a door of a vehicle, the door beam reinforcing the inner panel and the outer panel, the door beam comprising:

an upper inner flange arranged on the inner panel side;

a lower inner flange arranged on the inner panel side and below the upper inner flange;

an outer flange arranged on the outer panel side;

an upper rib that couples the upper inner flange to the outer flange;

a lower rib that couples the lower inner flange to the outer flange; and

an intermediate rib arranged between the upper rib and the lower rib, and projecting from the outer flange, wherein

a thickness of the outer flange is larger than a thickness of the upper inner flange and a thickness of the lower inner flange,

a thickness of the upper rib becomes gradually larger from the outer flange toward the upper inner flange, and

a thickness of the lower rib becomes gradually larger from the outer flange toward the lower inner flange.

8. The door beam according to claim 7 , wherein

a length of the intermediate rib in a vertical direction becomes shorter with increasing distance from the outer flange.

9. The door beam according to claim 7 , wherein

when the door beam has a symmetric shape with respect to a symmetric plane that is orthogonal to a vertical direction and passes through a center of the outer flange in the vertical direction, the intermediate rib is provided at a position that overlaps with the symmetric plane.

10. The door beam according to claim 9 , wherein

a projecting length of the intermediate rib from the outer flange is longer than a length of the intermediate rib in the vertical direction.

11. The door beam according to claim 7 , wherein

the upper inner flange includes an upper outward-protruding portion having a shape that protrudes upward from the upper rib in a vertical direction,

the lower inner flange includes a lower outward-protruding portion having a shape that protrudes downward from the lower rib in the vertical direction,

the upper rib includes:

an upper outer surface formed on an upper side in the vertical direction, and

an upper inner surface formed on a lower side in the vertical direction,

the lower rib includes:

a lower outer surface formed on the lower side in the vertical direction, and

a lower inner surface formed on the upper side in the vertical direction,

the upper outer surface is orthogonal to both the upper outward-protruding portion and the outer flange,

the lower outer surface is orthogonal to both the lower outward-protruding portion and the outer flange,

the upper inner surface has a shape that becomes gradually closer to the lower inner surface from the outer flange toward the upper inner flange, and

the lower inner surface has a shape that becomes gradually closer to the upper inner surface from the outer flange toward the lower inner flange.

12. The door beam according to claim 11 , wherein

the upper inner flange has a lower end face that continuously connects to the upper inner surface, and

the lower inner flange has an upper end face that continuously connects to the lower inner surface.