The invention has as its object to perform hydroforming so that no buckling or wrinkles remain at a hydroformed product with a long expanded region and comprises performing a first step of raising the internal pressure in a state with the metal tube fixed in position at the two ends or a state applying axial pushing actions of 10% or less of the total amount of axial pushing action, then applying axial pushing actions while holding the internal pressure at a constant pressure so as to expand the metal tube near the ends, then performing a second step of raising only the internal pressure without applying any axial pushing action so as to thereby expand a center of the metal tube, then performing a third step of lowering only the internal pressure to the value of the constant pressure without applying any axial pushing action, then repeating the first to third steps one or more times, then raising the internal pressure in the state not applying any axial pushing action or applying an axial pushing action of 10% of the total axial pushing action amount or less.

Method for hydroforming and a hydroformed product

A vehicle frame assembly includes a first vehicle frame component that is formed by deforming a closed channel structural member to have a relatively small end portion and a relatively large end portion. A member is provided having first and second ends. The relatively large end portion of the closed channel structural member is secured to the first end portion of the member to form the first vehicle frame component. A plurality of second vehicle frame components are provided. The first vehicle frame component and the plurality of second vehicle frame components are secured together to form the vehicle frame assembly.

Method of manufacturing a vehicle body and frame assembly

A hydroformed control arm for a vehicle and a method of making the same is provided. The control arm includes a generally U-shaped member being hydroformed from a continuous, unitary tube. The generally U-shaped member includes varying cross-sectional areas along its length for improved structural integrity. The generally U-shaped member further includes a pair of pivot bores for enabling the control arm to pivot about a pivot axis. The U-shaped member still further including a ball joint cavity disposed near its apex for receiving a ball joint. The hydroformed control arm thereby eliminates the need for a ball joint bushing.

Hydroformed control arm

The invention discloses a charging pressing forming method for a variable-cross-section special-shaped pipe, and relates to a forming manufacturing method of a metal pipe The problems that an existing low-internal-pressure forming technology only can form a pipe with the unchangeable section perimeter, and meanwhile, in the internal-high-pressure forming process of an advanced high-strength steel variable-cross-section pipe, the pressure is high, springback is large, and a mold is seriously worn are solved The forming method comprises the steps that firstly, an upper expansion mold and a lower expansion mold are assembled on a pressure machine; secondly, the upper expansion mold descends to perform mold assembly, a pipe blank is subject to charging, and the pipe blank expands until the pipe blank is attached to the mold; thirdly, the internal pressure of the pipe blank is relieved; fourthly, an upper pressing block and a lower pressing mold are assembled on a pressure machine; fifthly, the upper pressing block descends to perform mold assembly; sixthly, under the joint action of mechanical pressure of the mold and hydraulic pressure of an inner cavity of a variable-cross-section round pipe, mold attaching is carried out, the variable-cross-section round pipe is formed into the variable-cross-section special-shaped pipe, and the forming process is finished; and seventhly, the internal pressure of the variable-cross-section special-shaped pipe is relieved, and the variable-cross-section special-shaped pipe is cut, so that the variable-cross-section special-shaped pipe meeting the design requirement is obtained The method is used for forming the variable-cross-section special-shaped pipe

Charging pressing forming method for variable-cross-section special-shaped pipe

A device and method for expansion forming of an article used in conjunction with an isostatic press comprising a pressure cell equipped with an elastomeric membrane (3). The expansion forming tool (4) comprises at least one pressure intensifier (8) and at least one moulding cavity (6). A blank (5) is arranged in the moulding cavity (6) and an elastomeric forming body (7) is arranged inside the blank (5). The pressure intensifier is arranged such that it is acted upon by the elastomeric membrane (3) and pressure exerted on the elastomeric forming body (7) inside the blank (5) inside the moulding cavity (6) so that the blank (5) is expanded into an article shaped according to the shape of the moulding cavity (6).

Device and method for expansion forming

A method for hydroforming a metallic tube comprising primary hydroforming and secondary hydroforming, wherein in the primary hydroforming step, the metallic tube is formed such that a circumferential length of an expanded portion of the primary-hydroformed tube as measured at a wall center region of the expanded portion becomes substantially equal to or slightly shorter than a circumferential length of an expanded portion of a product as measured at a wall center region of the expanded portion, and in the secondary hydroforming step, movable pads incorporated in the dies press the expanded portion formed through primary hydroforming so as to finish the cross-sectional profile of the expanded portion into that of the expanded portion of the product, and said primary hydroforming and secondary hydroforming are continuously performed within the dies. Also disclosed is an apparatus for performing the hydroformation method. According to the method of the present invention, high liquid pressure is not required, and reduction in wall thickness and shape defects can be prevented.

Method and apparatus for hydroforming metallic tube

of EP0895820A method for hydroforming a metallic tube (1) comprising primary hydroforming and secondary hydroforming, wherein in the primary hydroforming step, the metallic tube (1) is formed such that a circumferential length of an expanded portion (2a';3a') of the primary-hydroformed tube as measured at a wall center region of the expanded portion (2a;3a) becomes substantially equal to or slightly shorter than a circumferential length of an expanded portion of a product (2a;3a) as measured at a wall center region of the expanded portion, and in the secondary hydroforming step, movable pads (43,44) incorporated in the dies (41,42) press the expanded portion formed through primary hydroforming so as to finish the cross-sectional profile of the expanded portion into that of the expanded portion (2a;3a) of the product (2;3), and said primary hydroforming and secondary hydroforming are continuously performed within the dies (41,42). Also disclosed is an apparatus for performing the hydroformation method. According to the method of the present invention, high liquid pressure is not required, and reduction in wall thickness and shape defects can be revented.

Masayasu Kojima

Papers

Method and apparatus for hydroforming metallic tube

Apparatus for hydroforming a metallic tube