Abstract: A vehicle wheel disk and a manufacturing method thereof is provided. The vehicle wheel disk is manufactured from a disk material of a flat plate. The vehicle wheel disk includes a hub coupling portion, a disk flange and a hat. The hat includes a hat top protruding outwardly in an axial direction of the disk, a radially inner hat portion connecting the hat top and the hub coupling portion, and a radially outer hat portion connecting the hat top and the disk flange. In the vehicle wheel disk, a first thickness-reduced portion is smaller in thickness than the disk material that is formed at the radially outer hat portion.

Abstract: A method of manufacturing a tubular member having a non-constant thickness by ironing at least a portion of the tubular material. The ironing apparatus can have a punch and a die, and the die can have a convex and concave side surface opposing the punch. The method can include bending an axial end portion of the tubular material to form a bent portion. The tubular material can then axially engage the die at the bent portion, and then the punch can be moved relative to the die to iron at least a portion of the tubular material.

Abstract: A vehicle wheel disk and a manufacturing method thereof is provided. The vehicle wheel disk is manufactured from a disk material of a flat plate. The vehicle wheel disk includes a hub coupling portion, a disk flange and a hat. The hat includes a hat top protruding outwardly in an axial direction of the disk, a radially inner hat portion connecting the hat top and the hub coupling portion, and a radially outer hat portion connecting the hat top and the disk flange. In the vehicle wheel disk, a first thickness-reduced portion is smaller in thickness than the disk material that is formed at the radially outer hat portion.

Abstract: A method of manufacturing a wheel rim for a vehicle includes an ironing step for ironing a tubular material to manufacture a tubular member having a non-constant thickness, using an ironing apparatus provided with a punch, a die whose side surface opposing the punch is a convex and concave surface, and a pressing member. At the ironing step, a flange portion of the tubular material is set at the die, then the pressing member is moved relative to the die thereby to squeeze the flange portion of the tubular material by the pressing member and the die, and then the punch is moved relative to the die to iron at least a portion of the tubular material except the flange portion of the tubular material to manufacture the tubular member having a non-constant thickness.

Abstract: A method of manufacturing a wheel rim for a vehicle includes an ironing step for ironing a tubular material to manufacture a tubular member having a non-constant thickness, using an ironing apparatus provided with a punch, a die whose side surface opposing the punch is a convex and concave surface, and a pressing member. At the ironing step, a flange portion of the tubular material is set at the die, then the pressing member is moved relative to the die thereby to squeeze the flange portion of the tubular material by the pressing member and the die, and then the punch is moved relative to the die to iron at least a portion of the tubular material except the flange portion of the tubular material to manufacture the tubular member having a non-constant thickness.

Abstract: A method of manufacturing a tubular member having a non-constant thickness by ironing at least a portion of the tubular material. The ironing apparatus can have a punch and a die, and the die can have a convex and concave side surface opposing the punch. The method can include bending an axial end portion of the tubular material to form a bent portion. The tubular material can then axially engage the die at the bent portion, and then the punch can be moved relative to the die to iron at least a portion of the tubular material.