A value stream method of manufacturing a plurality of vehicle structural rails includes feeding a coil of aluminum alloy sheet into a roll forming machine and forming a tubular shape with a seam, bobbin tool-friction stir welding the seam of the tubular shape and forming a welded tubular shape with a welded seam, cutting the welded tubular shape into a plurality of tubular sections, tube bending each of the plurality of tubular sections and forming a plurality of bent tubular sections, and hydroforming each of the plurality of bent tubular sections and forming a plurality of structural rails. The coil of aluminum alloy sheet may or may not be pre-treated and/or lubricated.

Provided is a device for manufacturing a bent pipe, the device being capable of reducing buckling. The device including: an inner core metal arranged inside a first pipe; and a bending mold to bend the first pipe. The inner core metal includes: an inner core metal body; a first inner movable portion coupled to the inner core metal body and swingable around a first rocking shaft orthogonal to a central axis of the inner core metal body; and a second inner movable portion coupled to the first inner movable portion and swingable around a second rocking shaft parallel to the first rocking shaft. The first inner movable portion has an enlarging diameter portion enlarged in diameter toward the second inner movable portion. The bending mold causes an inner surface of the first pipe to press the first inner movable portion and the second inner movable portion.

One aspect of the present disclosure is a manufacturing device by which the bent pipe is obtained by bending a double pipe. The device includes inner and intermediate core metals, a bending mold, and a controller. The controller executes: a first bending process in which first and second pipes are bent by the bending mold in a first direction in a first area of the double pipe where the inner and intermediate core metals are placed; a second bending process in which the first and second pipes are bent, after the first bending process, by the bending mold in a second direction in a second area of the double pipe where the inner and intermediate core metals are placed; and a first bending-back process in which the second pipe is bent, after the first bending process, in a direction opposite to the first direction in the first area.

One aspect of the present disclosure is a manufacturing device for a bent pipe by which the bent pipe is obtained by bending a double pipe. The manufacturing device for a bent pipe includes an inner core metal, an intermediate core metal, a bending mold, and a controller. The controller executes a first bending process, a second bending process, and a re-bending process. In the first bending process, a first pipe and a second pipe are bend in a first direction in a first area. In the second bending process, the first pipe and the second pipe are bent in a second direction in a second area. The second area has more distance from a coupling portion than the first area does. In the re-bending process, the second pipe is bent in the same direction as the second direction in the second area.

One aspect of the present disclosure is a manufacturing device for a bent pipe by which the bent pipe is obtained by bending a double pipe. The manufacturing device for a bent pipe includes an inner core metal, an intermediate core metal, a bending mold, and a controller. The controller executes a first bending process, a second bending process, and a re-bending process. In the first bending process, a first pipe and a second pipe are bend in a first direction in a first area. In the second bending process, the first pipe and the second pipe are bent in a second direction in a second area. The second area has more distance from a coupling portion than the first area does. In the re-bending process, the second pipe is bent in the same direction as the second direction in the second area.

One aspect of the present disclosure is a manufacturing device for a bent pipe. The manufacturing device includes an inner core metal placed inside a first pipe, and a tubular intermediate core metal placed between the first pipe and a second pipe. The intermediate core metal includes an intermediate core metal main body and a tubular first intermediate movable portion. The first intermediate movable portion is coupled to an end portion of the intermediate core metal main body, and swings about a first intermediate pivot axis relative to the intermediate core metal main body. The intermediate core metal main body includes an edge positioned closer to the first intermediate movable portion while the double pipe is bent. The edge intersects an imaginary plane orthogonal to a central axis of the second pipe at a position where the second pipe contacts the intermediate core metal.

One aspect of the present disclosure is a manufacturing device for a bent pipe. The manufacturing device includes an inner core metal placed inside a first pipe, and a tubular intermediate core metal placed between the first pipe and a second pipe. The intermediate core metal includes an intermediate core metal main body and a tubular first intermediate movable portion. The first intermediate movable portion is coupled to an end portion of the intermediate core metal main body, and swings about a first intermediate pivot axis relative to the intermediate core metal main body. The intermediate core metal main body includes an edge positioned closer to the first intermediate movable portion while the double pipe is bent. The edge intersects an imaginary plane orthogonal to a central axis of the second pipe at a position where the second pipe contacts the intermediate core metal.

One aspect of the present disclosure is a manufacturing device by which the bent pipe is obtained by bending a double pipe. The device includes inner and intermediate core metals, a bending mold, and a controller. The controller executes: a first bending process in which first and second pipes are bent by the bending mold in a first direction in a first area of the double pipe where the inner and intermediate core metals are placed; a second bending process in which the first and second pipes are bent, after the first bending process, by the bending mold in a second direction in a second area of the double pipe where the inner and intermediate core metals are placed; and a first bending-back process in which the second pipe is bent, after the first bending process, in a direction opposite to the first direction in the first area.

Provided is a device for manufacturing a bent pipe, the device being capable of reducing buckling. The device including: an inner core metal arranged inside a first pipe; and a bending mold to bend the first pipe. The inner core metal includes: an inner core metal body; a first inner movable portion coupled to the inner core metal body and swingable around a first rocking shaft orthogonal to a central axis of the inner core metal body; and a second inner movable portion coupled to the first inner movable portion and swingable around a second rocking shaft parallel to the first rocking shaft. The first inner movable portion has an enlarging diameter portion enlarged in diameter toward the second inner movable portion. The bending mold causes an inner surface of the first pipe to press the first inner movable portion and the second inner movable portion.

A round metal pipe 1 including a bend portion 10 is configured such that on an axial direction cross-section of the bend portion 10, an outer half portion 11b of a peripheral wall portion 11 of the bend portion 10 has an outwardly projecting, non-circular arc shape in which a central portion in a y direction, which is orthogonal to a bend radius direction x of the bend portion 10, forms an outermost peripheral portion 13, and a distance Lb from respective intermediate portions 15 between the outermost peripheral portion 13 and a pair of proximal end portions 14 of the outer half portion 11b to a pipe center O is shorter than a distance La from the outermost peripheral portion 13 to the pipe center O. Thus, advantages such as suppressing reductions in the sectional area and minimum inside width of the bend portion 10 and reducing flow path resistance can be obtained, and the round metal pipe 1 can be manufactured easily and appropriately.