Patent EA-001238-B1 (EA)
Title: High pressure hydroforming press
Inventor: JAEKEL FEDERICO G
IPC: B21D26/02
Filed: 1998-04-16
Abstract: 1. An apparatus for hydroforming a tubular metal blank comprising:  a die structure having an internal die surface defining a die cavity, said die cavity being constructed and arranged to receive the tubular metal blank; a hydroforming fluid source; a hydraulically driven tube-end engaging structure constructed and arranged to engage and substantially seal opposite ends of the tubular metal blank in said die cavity, said tube-end engaging structure being movable to longitudinally compress the tubular metal blank, said tube-end engaging structure constructed and arranged to receive hydroforming fluid from said hydroforming fluid source and having a hydroforming fluid supplying outlet through which hydroforming fluid can be provided to an interior of the tubular metal blank; a hydraulically driven pressure intensifying structure movable to pressurize said hydroforming fluid provided to the interior of the tubular metal blank and thereby expand a diameter of the blank until an exterior surface of the tubular metal blank generally conforms to that of said internal die surface; and a single hydraulic power source constructed and arranged to supply hydraulic fluid under pressure to said hydraulically driven pressure intensifying structure and said hydraulically driven tube-end engaging structure, said single hydraulic power source providing said hydraulic fluid under pressure to said hydraulically driven pressure intensifying structure in order to move said pressure intensifying structure and thereby pressurize said 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 said internal die surface, said single hydraulic power source providing said hydraulic fluid under pressure to said hydraulically driven tube-end engaging structure to enable said tube-end engaging structure 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. 2. An apparatus according to claim 1 wherein said hydraulically driven tube-end engaging structure comprises a pair of movable tube-end engaging members disposed on opposing sides of said die structure. 3. An apparatus according io claim 2 wherein said tube-end engaging members each has a longitudinal bore formed therein, and said pressure intensifying structure comprises a pair of pressure intensifying members disposed on the opposing sides of said die structure, each of said pressure intensifying member being mounted within an associated one of said bores of said tube-end engaging structures, each of said pressure intensifying members defining a pressure intensifying chamber within the associated one of said bores, said pressure intensifying chambers in fluid communication with the interior of the tubular metal blank in said die cavity through said fluid supporting outlets when said tube-end engaging members are engaged with the opposite ends of the tubular metal blank such that longitudinal, inward movement of said pressure intensifying members reduces a volume of each of said pressure intensifying chambers to thereby pressurize the hydroforming fluid provided to the interior of the tubular metal blank and expand the diameter of said tubular metal blank so that its exterior configuration conforms to that of said internal die surface. 4. An apparatus according to claim 1 wherein said tube-end engaging structure comprises a pair of tube-engaging members disposed on opposing sides of said die structure, one of said tube-end engaging members having a longitudinal bore formed therein, said single pressure intensifying structure comprising a single pressure intensifying member disposed on one of said opposing sides of said die structure, said single pressure intensifying member being mounted within said longitudinal bore of said one of said tube-end engaging members, said single pressure intensifying member defining a pressure intensifying chamber within said longitudinal bore of said one of said tube-end engaging members, said pressure intensifying chamber being in fluid communication with the interior of the tubular metal blank in said die cavity through a fluid supplying outlet of said one of said tube-end engaging members when said tube-end engaging members engage the opposite ends of the tubular metal blank such that longitudinal inward movement of said single pressure intensifying member reduces a volume of said pressure intensifying chamber, to 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 configuration conforms to that of said internal die surface. 5. An apparatus according to claim 2 wherein said die structure comprises a movable upper die portion and a fixed lower die portion, said upper die portion being movable between a closed position to define said die cavity with said lower die portion and an open position to respectively permit the tubular metal blank to be disposed on and removed from said lower die portion, said single hydraulic power source providing said hydraulic fluid to said upper die portion in order to move said upper die portion between said closed and open positions thereof. 6. An apparatus according to claim 1 wherein said tube-end engaging structure comprises a tube-end engaging tubular member having an internal cavity, and wherein said pressure intensifying structure comprises a movable member disposed within and movable with respect to said tube-end engaging tubular member. 7. An apparatus according to claim 1 wherein said hydroforming fluid source is disposed higher than said tube-end engaging structure such that said hydroforming fluid is provided to said tube-end engaging structure under the force of gravity. 8. An apparatus according to claim 2 wherein one of said tube-end engaging members comprises an internal cavity, and wherein said pressure intensifying structure comprises a movable member disposed within said one of tube-end engaging members 9. An apparatus according to claim 1, further comprising a valve assembly communicating said hydroforming fluid source and said single hydraulic power source with said pressure intensifying structure and said tube-end engaging structure, said valve assembly directing hydraulic fluid to move said tube-end engaging structure into compression with said opposite ends of said tubular metal blank and to move said pressure intensifying structure to pressure hydroforming fluid within said tubular metal blank so as to expand said tubular metal blank while maintaining the wall thickness of said tubular metal blank within said predetermined range, said valve assembly being adjustable to direct said hydraulic fluid to move said tube-end engaging structure away from said opposite ends of the tubular metal blank and to move said pressure intensifying structure to depressurize said hydroforming fluid after said hydroforming operation. 10. An apparatus according to claim 1 wherein said predetermined range is +- 10% of the wall thickness of an original tubular metal blank. 11. An apparatus for hydroforming a tubular metal blank comprising: a die structure having an internal die surface defining a die cavity, said die cavity being constructed and arranged to receive the tubular metal blank; a hydroforming fluid source disposed higher than said die cavity, and constructed and arranged to provide hydroforming fluid internally to said tubular metal blank under the force of gravity; a hydraulically driven tube-end engaging structure, constructed and arranged to engage and substantially seal opposite ends of the tubular metal blank in said die cavity, said tube-end engaging structure being movable to longitudinally compress the tubular metal blank; said tube-end engaging structure constructed and arranged to receive hydroforming fluid from said hydroforming fluid source and having a hydroforming fluid supplying outlet through which hydroforming fluid can be provided to an interior of the tubular metal blank; and a hydraulically driven pressure intensifying structure movable in response to hydraulic fluid pressure to pressurize said hydroforming fluid provided to the interior of the tubular metal blank and thereby expand a diameter of the blank until an exterior surface of the tubular metal blank generally conforms to that of said internal die surface, said hydraulically driven tube-end engaging structure being movable in response to hydraulic fluid pressure to enable said tube-end engaging structure 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. 12. An apparatus according to claim 11 wherein said hydroforming fluid source provides said hydroforming fluid through a first path to fill said. tubular metal blank prior to engagement of said tube-end engaging structure with the opposite ends of said tubular metal blank, and wherein said hydroforming fluid source provides said hydroforming fluid through a second path different from said first path to said tube-end engaging structure and through said fluid supplying outlet into said tubular metal blank after said tube-end engaging structure engages the opposite ends of said tubular metal blank. 13. An apparatus according to claim 12 wherein said hydroforming fluid is forced through said first path and through said second path under the force of gravity. 14. An apparatus according to claim i3 wherein said second path comprises a pump for facilitating flow