Showing papers on "Hydroforming published in 1996"

Method for hydroforming a vehicle space frame

Abstract: A vehicle space frame is built up piece by piece into an initial or rough frame, consisting of standard, cylindrical metal tubes welded to matching cylindrical plugs of hollow, nodal joints. All weld seams are circular and, therefore, easily and quickly formed, and the initial frame need be formed only with the accuracy that plugging the ends of the tubes into the joints will achieve. The entire interior of the initial frame is then clamped between a large pair of dies with mating cavities, and hydroformed to provide a final frame with the desired non cylindrical cross section and accurate, final shape and form.

Process of hydroforming tubular suspension and frame components for vehicles

Abstract: A process of hydroforming tubular suspension and frame components of a vehicle which results in substantial weight reductions while maintaining strength and integrity of the assembly. The process forms a hydroformed tubular trailing arm having a curved configuration to comply with the design requirements of the suspension. The trailing arm has a spring seat base hydroformed therein, an extruded shock mount and bushing mount formed as integral components. A mounting plate is attached to the trailing arm for attaching the vehicle wheel.

Frame structure for vehicle body

Abstract: At least one of the nodal elements (24-26) of the structure is a closed formed component made of steel plate. It is formed by hydroforming with the application of an internal high pressure. At least one connecting piece is formed directly on the nodal element and is for a combination with at least one preformed support element (27,28). The profiled shapes of the support elements are produced by hydroforming or extrusion or rolling or post-bending.

Hydroforming apparatus having in-die hole piercing capabilities and a slug ejection system using hydroforming fluid

Abstract: A hydroforming apparatus having in-die hole piercing capabilities and a slug ejection system is disclosed. The slug ejection system uses the pressurized hydroforming fluid as the motive force to eject the slug of material created by the in-die hole piercing system. The in-die hole piercing system includes a movable punch disposed within a bore formed in one of the die blocks. The bore opens into the die cavity. The punch includes a cutting edge on a first end which is adjacent the cavity. The hole is formed when the punch is inserted against a hollow workpiece positioned in the apparatus, thereby creating a slug of material. The slug ejection system includes two passageways formed internally to the same die block having the in-die hole piercing system. Both passageways open into and extend in a generally transverse direction to the bore. A first passageway is in fluid communication with the source of the hydroforming fluid. A second passageway is located generally opposite the first passageway and functions as a chute to catch the slug of material ejected by the hydroforming fluid supplied to the first passageway. The hydroforming fluid is supplied to the first passageway only after the workpiece has been hydroformed and remains pressurized and the punch is retracted to a position where it is generally aligned with both passageways.

Hydroforming offset tube

Abstract: Apparatus and method for mechanically and hydroform reconfigurating an elongated tubular workpiece in an elongated cavity between upper and lower tool subassemblies each composed of a plurality of independent tool segments movable axially, relative to the cavity axis, together or spaced from each other, and independently movable transversely of the cavity, usually vertically, in sequence, to grip the end portions of the workpiece while its ends are flared with tapered mandrels, and after the workpiece is filled with liquid, offset deform one workpiece portion while the tool segments are spaced apart and with axial infeed of workpiece material, then offset deform another portion with further axial infeed of workpiece material. Hydroforming pressure is then applied to partially expand the workpiece. Then after withdrawing segment spacing stops, forcing the tool segments together, and totally closing the tool, a greater hydroforming pressure is applied in the workpiece to expand it to the specific cavity configuration. After pressure is relaxed and the mandrels retracted, the tool segments are temporarily held together until the finished part is ejected and removed, and then allowed to separate under force of biasing springs.

Theoretical and Experimental Analysis of Failure for the Hemisphere Punch Hydroforming Processes

Abstract: A limit theorem of plasticity has been developed to investigate the hemisphere punch hydroforming process. The limit theorem of plasticity is used to predict the upper and lower bounds of the permissible fluid pressure. Loci representing the critical fluid pressures which result in the rupture and wrinkling are presented. The property of the sheet metal is governed by Hill's quadratic yield criterion with a power-law hardening for anisotropic material. The premature failure is avoidable if the fluid pressure path is restricted to travel only within the suggested bounds. The theoretical results which include the failure prediction and wrinkling distribution are verified by conducting a serial of hydroforming experiments. The experimental data agrees well with the computed results and demonstrates the technological usefulness of the results.

Hydroforming method of tube

Abstract: PROBLEM TO BE SOLVED: To improve workability by restraining an uneven wall and ductile deterioration at the time of bending, in the case of putting a metal tube such as a steel tube or the like into segmental dies after bending and hydroforming into a prescribed shape while applying pressure into the tube and thrusting in the axial direction of the tube. SOLUTION: A spherical body-like floating plug having a larger diameter than the inner diameter of a straight tubular tube stock 1 is installed to the chip end of a round bar-like core bar having a smaller diameter than the inner diameter of the tube stock 1 so that the center of the floating plug is movable in the optional direction within a given range with respect to the axial center of the core bar, the core bar is inserted into the tube stock 1, and the floating plug and the tube stock 1 are relatively moved under the state that the floating plug is eccentric to the core bar. Whereby, bending is executed while expanding the tube within the tube expansion ratio of 5-12% to obtain a bent tube 2, next the bent tube 2 is put into segmental dies 4, 5, pressure is applied into the tube, and the tube is worked into the prescribed shape while thrusting in the axial direction of the tube. COPYRIGHT: (C)1998,JPO

Hydroforming process obviating long-stroke, expensive machinery

Abstract: In the hydroforming tubular blanks (W), which is economical in machinery and highly-productive, the main press frame has a piston-cylinder closure system (5) acting on a moulding tool with two or more die halves (2, 3), in which high internal pressure will be applied to the tubular blank. Outside the closure system, during die closure, the swaging profile (G) of the die halves preforms the blank. Simultaneously, internal pressure P1 is introduced into the blank. During the remainder of the hydroforming process, the workpiece remains in the mould. Also claimed is the apparatus used for the above process.

Hydroforming method and apparatus

Abstract: Hydroforming double wall tubular stock (W) into an air gap tubular element comprising providing a plural wall tubular workpiece having at least an inner wall liner (L) and an outer wall jacket (J) having adjacent open axial ends, causing at least one of the jacket ends to extend axially beyond the adjacent liner end and to be flared outwardly, placing the workpiece into a first mold cavity (14) of a size and configuration to result in the desired size and configuration of the liner, sealing the open ends of said liner, injecting hydroforming fluid into said liner to fill it and applying pressure thereto to expand the liner and jacket in the first mold cavity, releasing the pressure, placing the workpiece in a second mold cavity (16) of a size and configuration desired for the jacket on a resulting air gap tubular element, providing hydroforming end closures (42) to seal off the jacket ends, at least one of the end closures having an annular shoulder (42') aligned with the flared extended jacket end radially outwardly offset from the adjacent liner end, pressing the annular shoulder directly against the flared jacket end to seal the flared jacket end between the shoulder and an anvil surface, injecting fluid into the workpiece to fill it and applying pressure to expand only the jacket.

Liquid-operated molding with duplicated control time

Abstract: PURPOSE: To obtain a hydroforming apparatus for rapidly forming a double wall conduit having the gap of a controlled size between the walls from dual wall tubular stock by providing the apparatus with a preform, semi-finish cavity and finish cavity. CONSTITUTION: The dual wall tubular exhaust conduit workpieces which are previously curved are successively arranged in a cavity 14 and are mechanically preformed by force mold clamping. A first pair of end plug sub-assemblies 20 exists at both ends of the cavity 14 and a hydroforming liquid is injected through the same. Both walls of the double wall workpieces are expanded up to the size of the cavity 14. The workpieces are thereafter arranged in the cavity 16 and the hydroforming liquid is injected from the end plug sub- assemblies 40. The pressurizing liquid equals the pressure acting on both of the inner walls and outer walls of internal elements through apertures. The external force is acted on the walls on the inner side of the external elements to expand the walls to the final dimensions of the cavity 16, by which these elements are arranged apart with the controlled exact spacings from the inner element.

Theoretical and experimental analysis of failure for the hemisphere punch hydroforming processes

Abstract: A limit theorem of plasticity has been developed to investigate the hemisphere punch hydroforming process. The limit theorem of plasticity is used to predict the upper and lower bounds of the permissible fluid pressure. Loci representing the critical fluid pressures which result in the rupture and wrinkling are presented. The property of the sheet metal is governed by Hill's quadratic yield criterion with a power-law hardening for anisotropic material. The premature failure is avoidable if the fluid pressure path is restricted to travel only within the suggested bounds. The theoretical results which include the failure prediction and wrinkling distribution are verified by conducting a serial of hydroforming experiments. The experimental data agrees well with the computed results and demonstrates the technological usefulness of the results.