Showing papers on "Hydroforming published in 1998"

Hydroformed tubular member and method of hydroforming tubular members

Abstract: Tubular members for use in vehicle frames are easily and economically produced using a hydroforming process in which a high pressure fluid is presented to the interior of a tubular member, thus causing the tube to expand to meet the interior walls of a forming die. Tubular members can be formed having significant variations in their circumference, diameter along their lengths, or gage along their lengths by using a stamped blank having a predetermined shape which is formed into a preformed tube which roughly mirrors the shape of the desired finished tubular member.

Method and apparatus for hydroforming metallic tube

Abstract: 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.

High pressure hydroforming press

Abstract: An apparatus for hydroforming a tubular metal blank has a die structure (12), a hydroforming fluid source, a hydraulically driven tube-end engaging structure (36), a hydraulically driven pressure intensifying structure (110), and a single hydraulic power source (22). The tube-end engaging structure (36) seals opposite ends of the tubular metal blank (T) in said die cavity and is movable to longitudinally compress the tubular metal blank (T). The tube-end engaging structure receives hydroforming fluid from said hydroforming fluid source and has a hydroforming fluid supplying outlet through which hydroforming fluid can be provided to the tubular metal blank. The hydraulically driven pressure intensifying (110) structure is movable to pressurize the hydroforming fluid provided to the interior of the tubular metal blank and thereby expand a diameter of the blank. A single hydraulic power source (22) provides the hydraulic fluid under pressure to said hydraulically driven pressure intensifying structure (110) in order to move the pressure intensifying structure (110) and thereby pressurize the hydroforming fluid provided to the interior of the tubular metal blank and expand the diameter of the tubular metal blank so that its exterior surface conforms to that of the internal die surface. The single hydraulic power source (22) also provides the hydraulic fluid under pressure to the hydraulically driven tube-end engaging structure to enable the tube-end engaging structure (36) to longitudinally compress the tubular metal blank and cause metal material of the diametrically expanded tubular blank to flow longitudinally inwardly in order to replenish a wall thickness of the diametrically expanded tubular metal blank and maintain the wall thickness thereof within a predetermined range.

System and method for manufacturing tubular products from tubular workpieces

Abstract: A system for forming tubular metal products from tubular workpieces by hydroforming achieving single-step radial expansion of 70-150% with high dimensional accuracy. Enhanced single-step radial expansion is achieved by maintaining a predetermined functional relationship among the driving parameters of the hydroforming process and by increasing the plasticity of the workpiece by employing the fractional deformation effect and by applying ultrasound oscillations and alternating angular strains to the workpiece.

A method of securing components together and a structural member made by said method

Abstract: A method of securing two or more components together is disclosed in which one of the members is made from a thin wall tubular material that can be expanded by a hydroforming technique to cause deformation which is used to secure one or more components (11, 12, 13, 14; 111, 122, 123 and 114) to the tubular member (9, 109).

Method of hydroforming a vehicle frame component

Abstract: A method for hydroforming a closed channel member (10) that allows the perimeter to be increased, but which maintains a uniform wall thickness throughout, includes the initial step of disposing a closed channel member (10), such as a tube, within a first hydroforming die (11) defining a first die cavity (12a, 13a). The inner surface of the first die cavity (12a, 13a) corresponds in cross sectional shape to the outer surface of the tube throughout some or all of the length thereof. A preliminary hydroforming operation is performed at a high pressure to expand the tube into conformance with the first die cavity (12a, 13a). The preliminary expanded tube is disposed within a second hydroforming die (15) defining a second die cavity (16a, 17a). The inner surface of the second die cavity (16a, 17a) corresponds in cross sectional shape to the desired final shape for the tube. When the second hydroforming die is closed, a final hydroforming operation is performed at a low pressure to deform the tube into conformance with the second die cavity (16a, 17a).

Multi-piece hydroforming tool

Abstract: A multi-piece hydroforming tool is provided having a tooling die and a hydraulic pressure source. The tooling die includes a plurality of tooling cavities. Each tooling cavity includes a injector manifold in fluid communication with the hydraulic pressure source. The injector manifolds supply pressurized hydraulic fluid to each of the plurality of tooling cavities independently. Thus, multiple pieces may be formed simultaneously and independently, thereby minimizing the need to discard all the hydroformed pieces if one piece become defective.

Tube hydroforming : efficiency and effectiveness of pressure sequence hydroforming

Abstract: Tube hydroforming is a technology that is new to many and proving it’s merits as a viable and often superior alternative to welding tubular assemblies from stampings. This paper discusses how pressure sequence and high pressure hydroforming techniques work, how two functionally similar parts made by its respective technology compare and the dimensional stability of parts made with pressure sequence hydroforming. Data comparing the 2 processes show a substantial benefit when using pressure sequence hydroforming considering processing steps, hydroforming equipment, energy consumption, cycle time and floor space requirements. PSH dimensional stability compares very well with welded assemblies. High pressure dimensional data is unavailable which prevents comparison. Comparisons using specific information that has only recently become available should be interesting and valuable to anyone wanting to learn more about this emerging industry and technology.

Hydroformed hose fittings and related hose assemblies

Abstract: A system and method for hydroforming hose fittings for use with hose assemblies. Hose fittings of hydroformed metal provide variuos structural, performance and manufacturing benefits.

Method and apparatus for fabricating a hollow body

Abstract: In a method and apparatus for fabricating a hollow body, preferably of sheet metal, such as for example automobile hoods and doors, at least two blanks are held sealingly together and the hollow body is then shaped by internal hydroforming.

A General Formulation for Hydroforming of Arbitrarily-Shaped Boxes and Its Application to Hydroforming of an Elliptic-Circular Box

Abstract: A general kinematically admissible velocity field is suggested for the upper-bound solution of hydroforming of arbitrarily-shaped boxes. The suggested formulation is then applied to hydroforming of an elliptic-circular box. From the proposed velocity field, the fluid pressure vs. punch stroke relationship to render uniform thickness and the deformed configuration are determined by minimizing the total power consumption with respect to some chosen parameters. Experiments are carried out in the hydroforming press according to the computed pressure vs. punch stroke curve. The assumption of uniform wall thickness is confirmed by measuring the thickness variation. The effects of various process parameters including blank size, work-hardening exponent and frictional coefficient on the pressure curve are analyzed and discussed. It is thus shown that the proposed method of analysis in the present study can be effectively used for hydroforming of arbitrarily-shaped boxes.

Securing components together and a structural member so formed

Abstract: Two or more components, one of which 9 is made from a thin wall tubular material, are secured together by a hydroforming technique to cause expansion of the tubular member 9 to secure one or more components 11, 12, 13, 14; through which it passes to it. The thus formed member may be a transverse component to carry a steering column and air bag housing.

On materials for lean weight vehicles

Abstract: This article reports on the designs and uses of lighter materials for cars, which can decrease vehicle weight to lower fuel consumption, but satisfy safety and environment laws and meet customer demands for increased comfort and convenience. The ULSAB programme by a consortium of 35 steel makers is exploring the potential for using high-strength steels to reduce weight, and uses advanced manufacturing technologies such as laser welding, tailored blanks, and hydroforming. Many car makers are evaluating compacted graphite iron (CGI) for possible use in petrol and diesel cylinder blocks and heads. Aluminium can give an equivalent performance to steel, and save about 60% in weight; its components can be made by casting, forging, sheet and strip, extrusion, powder metallurgy, or superplastic forming. Magnesium is about 1.5 times lighter, but magnesium alloy parts have more dimensional stability than aluminium parts; magnesium damps vibration better than aluminium or steel. Titanium provides the strength of steel at about half its weight, but is expensive. Metal matrix composites for cars are based on aluminium or magnesium with powder or chopped-fibre reinforcement. Plastics are used to reduce weight for a wide variety of components throughout the car. Many different approaches to weight reduction are being used.

Production of a component for reducing the effects of an external mechanical impact, and the component produced in this way

Abstract: A process for producing a component for reducing the effect of an external mechanical impact, of the type which comprises an essentially tubular metal element which has a jump in its cross section which is such that under the influence of an axial load it can be turned at least partially inside-out as a result of plastic deformation, by means of which process the tubular element is formed by hydroforming from a piece of tube which has a cross section which is constant along its length, during which process part of the length of the cross section is increased in size, and the transitions in the cross section cover a short distance, and during the hydroforming an axial pressure on the piece of tube which is being deformed is set to be such that the transitions in cross section adapt to an S-shape.

Apparatus for hydroforming a metallic tube

Abstract: 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.

A 2-D non-local analysis of hydroforming for thin sheets

Abstract: An enhanced membrane theory is used to analyse hydroforming of thin metal sheets. The use of a plane stress or membrane model for such metal forming studies, rather than a full three dimensional numerical analysis, is highly advantageous from the point of view of reducing computer requirements, but the onset and development of localized plastic straining is not realistically predicted. It has been found that a nonlocal formulation of a membrane model, in which a material length is used to represent thickness effects, can give rather accurate predictions of the full 3-D effects. The non-local model implemented here in a hydroforming study is a 2-D version of gradient dependent plasticity theory. The model is used to illustrate the effect of different initial geometries and of different material length parameters.

Method for producing an elongated hollow body and its use

Abstract: The invention relates to a method for making an elongate hollow body from naturally hard aluminum, for example AlMgMn or a hardenable such as aluminum alloy, such as AlMgSi1 as well as the use of such hollow body as an integral part of chassis carriers in vehicle construction. In the production of at least two sheets of different wall thickness are joined to a circuit board. Then the blank is formed into a hollow body and a joining technique joined at their longitudinal edges. takes place the final shaping of the hollow body by hydraulic hydroforming.

2D finite element simulation of tube hydroforming process

Abstract: Tube hydroforming is receiving the greatest attention especially in the automotive industry. The advantages of this process when compared to traditional manufacturing methods are considerable including savings, weight reduction, quality improvement and accuracy. An internal pressure inside the tubes achieves the forming. Axial forces can also be applied simultaneously to optimise material flow during expansion. The finite element analysis could help to determine the optimum parameters for this forming process. In this work, axisymmetric numerical simulation is presented. The numerical model is based on implicit formulation of mechanical equilibrium The elastoviscoplastic constitutive equation includes work hardening and strain rate effects. The hydroforming of a tube is limited by the occurrence of necking. The forming limit diagram is very helpful to evaluate the margin with respect to the limit pressure and to optimise the global pressure cycle.

Mirror stay for vehicle and its manufacture

Abstract: PROBLEM TO BE SOLVED: To provide a mirror stay for vehicle which stably holds an outside mirror, etc., has the vibration rigidity to the exciting force, etc., applied during the traveling, and is formed light and inexpensive, and prevents the primary resonance, and its manufacturing method. SOLUTION: A mirror stay 1 for vehicle comprises a perpendicular rod part 2 to support an outside mirror 11 and an under mirror 12 at their intermediate part, and a horizontal rod part 3 which is bent toward approximately horizontal direction from upper and lower ends and expanded toward each end part. The bending strength by the bending moment to be applied to this part is improved through expansion of the horizontal rod part 3. The thickness of an end part 4 is smaller than the thickness of the perpendicular rod part 2, and the whole is formed by the hydroforming method to reduce the weight, to prevent the primary resonance, and to facilitate the manufacture.

Hydroforming of a tubular blank having an oval cross section and hydroforming apparatus

Abstract: The present invention relates to a method and apparatus for forming an elongated tubular metal member from a tubular metal blank. The method comprises: i) placing a tubular metal blank having a generally oval cross section into a die cavity and orienting the tubular metal blank such that a relatively larger cross-sectional dimension of the generally oval cross section extends generally in a direction of the relatively larger cross-sectional dimension of the die cavity and such that a relatively small cross-sectional dimension of the generally oval cross section extends generally in a direction of the relatively small cross-sectional dimension of the die cavity; ii) engaging and sealing opposite ends of the tubular metal blank; and iii) injecting fluid under pressure into the tubular metal blank so as to expand the tubular metal blank into conformity with the surfaces defining the die cavity and thereby transform the tubular metal blank into the elongated tubular metal member.