Curved plate for railcar bodyshell, front car bodyshell, and method of manufacturing curved plate for railcar bodyshell

1. A curved plate for a railcar bodyshell, the curved plate comprising:

a plate main body including: (i) an outer surface facing an outside of a railcar, and (ii) an inner surface facing an inside of the railcar, the plate main body having a curved shape; and

a plurality of reinforcing ribs projecting from the inner surface of the plate main body toward the inside of the railcar, at least two of the plurality of reinforcing ribs respectively including machining reference surfaces formed on a same plane as reference surfaces used when machining an outer surface of the plate main body such that the outer surface has the curved shape, and at least one of the plurality of reinforcing ribs including a mounting reference surface perpendicular to one of: a rail direction, a sleeper direction, and a vertical direction as a reference surface used when mounting the curved plate to the railcar.

2. The curved plate according to claim 1 , wherein each machining reference surface and the mounting reference surface are surfaces different from each other.

3. The curved plate according to claim 1 , wherein at least one of the plurality of reinforcing ribs has a U shape in a plan view.

4. A front car bodyshell comprising:

an outside plate formed by the curved plate according to claim 1 ; and

a frame fixed to the outside plate from the inside of the railcar, wherein

at least a part of the outside plate is formed by machining.

5. The front car bodyshell according to claim 4 , wherein an end surface of the frame is welded to the machining reference surfaces of the reinforcing ribs of the curved plate.

6. A method of manufacturing a curved plate for a front car of a railcar bodyshell, the method comprising:

forming a plurality of reinforcing ribs to an upper surface of a metal material by machining the upper surface of the metal material, the plurality of reinforcing ribs projecting upward;

forming machining reference surfaces on at least two of the plurality of reinforcing ribs, the machining reference surfaces being formed on same plane;

forming on at least one of the plurality of reinforcing ribs a mounting reference surface perpendicular to one of: a rail direction, a sleeper direction, and a vertical direction as a reference surface used when mounting the curved plate to the railcar;

turning upside down the metal material, on which the plurality of reinforcing ribs are formed;

placing the machining reference surfaces on a surface plate of a machining device; and

forming, by the machining device, a plate main body by machining an upper surface of the metal material such that the metal material has the curved shape, machining reference surfaces of the upper surface of the metal material being placed on the surface plate.

7. A curved plate for a railcar bodyshell, the curved plate comprising:

a plate main body including: (i) an outer surface facing an outside of a railcar, and (ii) an inner surface facing an inside of the railcar, the plate main body having a curved shape: and

a plurality of reinforcing ribs projecting from the inner surface of the plate main body toward the inside of the railcar, at least two of the plurality of reinforcing ribs respectively including machining reference surfaces formed on a same plane as reference surfaces used when machining an outer surface of the plate main body, and at least one of the plurality of reinforcing ribs including a mounting reference surface perpendicular to one of: a rail direction, a sleeper direction, and a vertical direction as a reference surface used when mounting the curved plate to the railcar, wherein:

the mounting reference surface includes a projecting-side tip end surface of the at least one of the plurality of reinforcing ribs; and

the tip end surface inclines relative to a direction perpendicular to a projecting direction of the at least one of the plurality of reinforcing ribs.