A method of fabricating a metal cup includes a tool having an interior profile of a predetermined shape, the tool having a body forming an inner area; placing a metal sleeve within the inner area of the tool; securing the tool in a closed position such that the metal sleeve is unremovable; applying internal pressure within the inner area and within an inside of the sleeve such that the internal pressure exceeds a yield point of a material comprising the metal sleeve, the metal sleeve deforms into the interior profile; opening the body of the tool; and removing the metal sleeve from the tool in the open position; the metal sleeve maintains a deformed shape having an exterior profile that matches the interior profile of the tool.

A bellows having tweezers-shaped corrugated portions for increasing resistance and restoring force against torsion includes: a first flat part having a flat cylindrical shape; a second flat part having a flat cylindrical shape and disposed opposite to the first flat part; and a plurality of corrugated portions, each having a tweezers shape and disposed between the first flat part and the second flat part, wherein each of the plurality of corrugated portions is sequentially connected to each other, so as to increase resistance and restoring force against torsion.

A bellows having tweezers-shaped corrugated portions for increasing resistance and restoring force against torsion includes: a first flat part having a flat cylindrical shape; a second flat part having a flat cylindrical shape and disposed opposite to the first flat part; and a plurality of corrugated portions, each having a tweezers shape and disposed between the first flat part and the second flat part, wherein each of the plurality of corrugated portions is sequentially connected to each other, so as to increase resistance and restoring force against torsion.

A forming apparatus includes: an upper die and a lower die having forming surfaces corresponding to outer surfaces of a pipe with protrusions; a moving mechanism that moves the upper die and the lower die such that a forming space for forming the pipe with protrusions is defined between the forming surfaces of the upper die and the lower die; and a gas supply unit that supplies gas to a forming material to expand the forming material. A control unit controls the movement of the upper die and the lower die by the moving mechanism and the supply of gas to the forming material by the gas supply unit such that the forming material is formed into the pipe with protrusions in the forming space.

A forming apparatus includes: an upper die and a lower die having forming surfaces corresponding to outer surfaces of a pipe with protrusions; a moving mechanism that moves the upper die and the lower die such that a forming space for forming the pipe with protrusions is defined between the forming surfaces of the upper die and the lower die; and a gas supply unit that supplies gas to a forming material to expand the forming material. A control unit controls the movement of the upper die and the lower die by the moving mechanism and the supply of gas to the forming material by the gas supply unit such that the forming material is formed into the pipe with protrusions in the forming space.

A method of fabricating a metal cup includes a tool having an interior profile of a predetermined shape, the tool having a body forming an inner area; placing a metal sleeve within the inner area of the tool; securing the tool in a closed position such that the metal sleeve is unremovable; applying internal pressure within the inner area and within an inside of the sleeve such that the internal pressure exceeds a yield point of a material comprising the metal sleeve, the metal sleeve deforms into the interior profile; opening the body of the tool; and removing the metal sleeve from the tool in the open position; the metal sleeve maintains a deformed shape having an exterior profile that matches the interior profile of the tool.

A structure of the hollow torque transmission member having a bellows portion in the middle section in the axial direction is manufactured at low cost by bulge molding such as hydroforming molding. A thin thickness portion having a smaller thickness in the radial direction than other portion is provided in the middle section in the axial direction of a hollow material. A hollow torque transmission member comprising a bellows portion is obtained by expanding the thin thickness portion outward in the radial direction by performing hydroforming molding to the hollow material.

A structure of the hollow torque transmission member having a bellows portion in the middle section in the axial direction is manufactured at low cost by bulge molding such as hydroforming molding. A thin thickness portion having a smaller thickness in the radial direction than other portion is provided in the middle section in the axial direction of a hollow material. A hollow torque transmission member comprising a bellows portion is obtained by expanding the thin thickness portion outward in the radial direction by performing hydroforming molding to the hollow material.

The present invention relates to a bellows having tweezers-shaped corrugated portions for increasing resistance and restoring force against torsion, and a method for manufacturing the same, the bellows comprising: a first flat part having a flat cylindrical shape; a second flat part having a flat cylindrical shape and disposed opposite to the first flat part; and a plurality of corrugated portions, each having a tweezers shape and disposed between the first flat part and the second flat part, wherein each of the plurality of corrugated portions is sequentially connected to each other, so as to increase resistance and restoring force against torsion.

A forming device includes: an upper die and a lower die having forming surfaces corresponding to outer surfaces of a pipe with protrusions; a moving mechanism that moves the upper die and the lower die such that a forming space for forming the pipe with protrusions is defined between the forming surfaces of the upper die and the lower die; and a gas supply unit that supplies gas to a forming material which is the base of the pipe with protrusions to expand the forming material. A control unit controls the movement of the upper die and the lower die by the moving mechanism and the supply of gas to the forming material by the gas supply unit such that the forming material is formed into the pipe with protrusions in the forming space.