Door impact beam

1. A door impact beam for a vehicle, the door impact beam comprising:

a top plate facing an outer panel that constitutes a door of the vehicle and extending in the front-rear direction of the vehicle;

a recessed bead disposed on the top plate and having a U shape toward an inner panel that constitutes the door of the vehicle; and

walls protruding toward the inner panel from both ends of the top plate in a width direction of the top plate, wherein

the door impact beam is formed by press-molding a sheet-metal composite,

the sheet-metal composite includes a sheet-metal main body and a reinforcing sheet metal overlapping with a part of the sheet-metal main body in a longitudinal direction, and the door impact beam extends in a front-rear direction of the vehicle in an internal space formed by the outer panel and the inner panel, and wherein the sheet-metal main body is the longest component of the door impact beam; and, as the door impact beam is formed by press-molding the sheet-metal composite, the reinforcing sheet metal overlapping the sheet-metal main body has a common cross-sectional shape as that of the sheet-metal main body as to be fully flush with the main body over an entire lateral direction of the reinforcing sheet metal.

2. The door impact beam according to claim 1 , wherein

the recessed bead comprises a curved surface.

3. The door impact beam according to claim 1 , wherein

the reinforcing sheet metal of the door impact beam is disposed at a position corresponding to a side surface of a seat of the vehicle.

4. The door impact beam according to claim 2 , wherein

the reinforcing sheet metal of the door impact beam is disposed at a position corresponding to a side surface of a seat of the vehicle.

5. The door impact beam according to claim 1 , wherein

the recessed bead has a shape such that a depth from an opening to a bottom surface is deepest at a substantially central part in the front-rear direction of the vehicle and gradually becomes shallower toward both ends in the longitudinal direction.

6. The door impact beam according to claim 2 , wherein

the recessed bead has a shape such that a depth from an opening to a bottom surface is deepest at a substantially central part in the front-rear direction of the vehicle and gradually becomes shallower toward both ends in the longitudinal direction.

7. The door impact beam according to claim 5 , wherein

a maximum bead depth is less than a height extension of the walls protruding toward the inner panel such that a cross-section of the central part of the impact beam has a hat shape.

8. The door impact beam according to claim 1 , wherein

a maximum bead depth is less than a height extension of the walls protruding toward the inner panel such that a cross-section of the impact beam has a hat shape at a location of the maximum bead depth.

9. A door impact beam for a vehicle, the door impact beam comprising:

a top plate facing an outer panel that constitutes a door of the vehicle and extending in the front-rear direction of the vehicle;

a recessed bead disposed on the top plate and having a U shape toward an inner panel that constitutes the door of the vehicle; and

walls protruding toward the inner panel from both ends of the top plate in a width direction of the top plate, wherein

the door impact beam is formed by press-molding a sheet-metal composite,

the sheet-metal composite includes a sheet-metal main body and a reinforcing sheet metal overlapping with a part of the sheet-metal main body in a longitudinal direction, and

the door impact beam extends in a front-rear direction of the vehicle in an internal space formed by the outer panel and the inner panel, wherein the recessed bead has a shape such that a depth from an opening to a bottom surface is deepest at a substantially central part of the door impact beam in the front-rear direction of the vehicle and gradually becomes shallower toward both ends in the longitudinal direction, and wherein a maximum bead depth is set to be less than a height extension of the walls extending away from the top plate and toward the inner panel such that a cross-section of the central part of the impact beam has a hat shape.

10. The door impact beam according to claim 9 , wherein

the recessed bead comprises a curved surface.

11. The door impact beam according to claim 9 , wherein

the reinforcing sheet metal of the door impact beam is disposed at a position corresponding to a side surface of a seat of the vehicle.

12. The door impact beam according to claim 1 , wherein

the sheet-metal main body, in extending in the front-rear direction of the vehicle, has an end that has a substantially flat plate shape.

13. The door impact beam according to claim 9 , wherein

the sheet-metal main body, in extending in the front-rear direction of the vehicle, has an end that has a substantially flat plate shape.

14. The door impact beam according to claim 1 , wherein

the bead has a fully curved surface as to avoid any bend region in the bead in extending from one end to an opposite end of the bead in a widthwise direction.

15. The door impact beam according to claim 9 , wherein

the bead has a fully curved surface as to avoid any bend region in the bead in extending from one end to an opposite end of the bead in a widthwise direction.

16. The door impact beam according to claim 1 , wherein

the sheet-metal main body and the reinforcing sheet metal are joined to each other with a spot weld.

17. The door impact beam according to claim 9 , wherein

the sheet-metal main body and the reinforcing sheet metal are joined to each other with a spot weld.