EP1197274A1 - High pressure hydroforming press - Google Patents
High pressure hydroforming press Download PDFInfo
- Publication number
- EP1197274A1 EP1197274A1 EP01127374A EP01127374A EP1197274A1 EP 1197274 A1 EP1197274 A1 EP 1197274A1 EP 01127374 A EP01127374 A EP 01127374A EP 01127374 A EP01127374 A EP 01127374A EP 1197274 A1 EP1197274 A1 EP 1197274A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- tube
- end engaging
- hydroforming
- tubular metal
- engaging structure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
- B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
- B21D26/033—Deforming tubular bodies
- B21D26/041—Means for controlling fluid parameters, e.g. pressure or temperature
Definitions
- the present invention relates to a hydroforming system which requires less capital investment to achieve high pressure hydroforming of tubular parts.
- the present invention relates to a replacement for the conventional, separate "intensifier" system for providing high internal pressures within the tubular blank to be expanded.
- Conventional hydroforming utilizes low pressure hydroforming fluid feed from a supply tank to supply hydroforming fluid for quick pre-filling of the tube blank after the die cavities have closed on the tube but prior to the axial cylinders engaging the tube blank into the cavity. As a result, a separate intensifier is necessary push the tube blank into the die cavity.
- Such a hydroforming press is known from US 3,350,905. It comprises a tube-end engaging structure movable to longitudinally compress a tubular blank, hydraulically driven by a dedicated pump and a hydroforming fluid supply system consisting of a low pressure pump for pre-filling the tube blank, a high pressure pump energizing a pressure multiplier and a conduit for adducting the hydroforming fluid from the external fluid supply system to one tube-end engaging structure.
- the high pressure pump further supplies pressure cylinders by means of a balancing cylinder in order to compensate the force applied by the pressurized hydroforming fluid on the tube-end engaging structure from within the tube blank.
- This system is not only costly, not the least by employing three pumps, but it also needs a sophisticated control system for balancing the transient forces of the hydroforming fluid within the tube blank and of the tube-end engaging structure. Deficiencies of this control system tend to either destroy the tube blank or loss of hydroforming fluid where the tube-end engaging structure joins the tube blank, the latter leading to incomplete deformation.
- a further drawback of this system resides in the distance for adducting the highly pressurized hydroforming fluid from the immobile pump and pressure multiplier to the longitudinally mobile tube-end engaging structure and from there to the inside of the tube blank. It is prown to leakage and limits the hydroforming pressure.
- the disadvantages of the prior art may be overcome by providing an apparatus which uses the hydroforming fluid from a tank to supply a relatively smaller amount of water to intensify the pressure within the tubular blank after it is sealed and is ready to be expanded.
- This smaller amount of water is supplied to a dual function cylinder used for pushing the tube blank into the die cavity as well as intensifying the fluid pressure inside the die cavity from one side of the tool.
- water is fed under relatively low pressure to side ram or hydraulic cylinder assemblies which are used to expand the tubular blank.
- the side ram assemblies utilize the same hydraulic power source to exert the pressure that is required to expand the tube as well as the pressure that is required to force the opposite ends of the tube inwardly to retain the desired wall thickness of the resultant product.
- no separate intensifier is required.
- the present invention preferably also utilizes the same hydraulic power source to also apply the downward pressure to an upper die structure when the upper die structure is in ist lowered position to oppose the internal die cavity pressure during tube pressurization.
- the tube-end engaging structure seals opposite ends of the tubular metal blank in said die cavity and is movable to longitudinally.
- an apparatus for hydroforming a tubular metal blank comprising a die structure, a hydroforming fluid source, a hydraulically driven tube-end engaging structure, and a hydraulically driven pressure intensifying structure.
- the die structure has an internal die surface defining a die cavity.
- the die cavity is constructed and arranged to receive the tubular metal blank.
- the hydroforming fluid source is disposed higher than the die cavity, and is constructed and arranged to provide hydroforming fluid internally to the tubular metal blank under the force of gravity.
- the hydraulically driven tube-end engaging structure engages and substantially seal opposite ends of the tubular metal blank in the die cavity.
- the tube-end engaging structure is movable to longitudinally compress the tubular metal blank.
- the tube-end engaging structure receives hydroforming fluid from the hydroforming fluid source and has a hydroforming fluid supplying outlet through which hydroforming fluid can be provided to an interior of the tubular metal blank.
- the hydraulically driven pressure intensifying structure is movable in response to hydraulic fluid pressure to pressurize the 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 the internal die surface.
- the hydraulically driven tube-end engaging structure is movable in response to hydraulic fluid pressure to enable the 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.
- the resultant system is much less complex, less cumbersome, and less expensive then conventionally known systems.
- the hydroforming system 10 includes a hydroforming die structure 12, which includes an upper die portion 14 and a lower die portion 16.
- the lower die portion 16 is mounted on a rigid base 18.
- the upper die portion 14 is carried by an upper hydraulic ram 20, which controls vertical movement of the upper die portion 14. More particularly, the upper ram 20 is hydraulically actuated to permit the weight of the die portion 14 to move the upper die portion 14 vertically downwardly into cooperation with the lower die portion 16 at the beginning of a hydroforming operation. In addition, after the upper die portion 14 is lowered, the upper ram 20 applies a downward hydraulic force to the upper die portion 14 to maintain the upper die portion 14 in cooperative relation with the lower die portion 16 during high pressure conditions formed within the die cavity between the upper and lower die portions 14,16.
- a hydraulic pump assembly 22 is constructed and arranged to provide hydraulic fluid under pressure to the upper ram 20 via hydraulic fluid line 24 to meintain the upper die portion 14 in cooperative relation with the lower die portion against the opposing force created by the high die cavity pressure conditions as aforesaid.
- a servo valve 26 is disposed in the fluid line 24 to regulate fluid flow between the hydraulic pump assembly 22 and the upper ram 20.
- the hydraulic pump assembly 22 is also connected with a pair of side ram assemblies 28 and 30 disposed at opposite longitudinal ends of the die structure 12.
- the side ram assemblies 28,30 include respective ram housings 32 and 34, and respective tube-end engaging structures 36 and 38.
- the tube-end engaging structure 36 projects outwardly from the side ram housing 32, and the tube-end engaging structure 38 projects outwardly from the side ram housing 34.
- the tube-end engaging structure 36 is movable inwardly from the ram housing 32 and into engagement and sealing relation with one end of a tube T carried by the lower die portion 16.
- the tube-end engaging structure 38 is movable inwardly from the ram housing 34 and is constructed and arranged to engage and seal the opposite end of the tube T.
- the tube-end engaging structure 36 will move inwardly and outwardly with respect to the ram housing 32 based upon hydraulic fluid provided to the side ram assembly 28 by the hydraulic pump assembly 22 through three separate hydraulic fluid lines 40, 42 and 44 as shown.
- Servo valves 46, 48 and 50 are disposed in the fluid lines 44, 42 and 40, respectively, for controlling fluid flow between the pump assembly 22 and side ram assembly 28.
- the side ram assembly 30 is connected with the hydraulic pump assembly 22 for controlled movement of the tube-end engaging structure 38.
- the side ram assembly 30 is connected with the hydraulic pump assembly 22 via three separate hydraulic fluid lines 52, 54 and 56, as shown.
- Servo valves 58, 60 and 62 are disposed within the fluid lines 52, 54 and 56, respectively, for controlling fluid flow between the pump assembly 22 and side ram assembly 30.
- the hydroforming apparatus 10 further includes an upper water tank 80 constructed and arranged to hold a prescribed amount of water.
- the water tank 80 is connected via fluid line 82 to the tube-end engaging structure 36 of side ram assembly 28.
- a servo valve 84 is disposed in the fluid line 82 and controls water flow into the tube-end engaging structure 36 when it is engaged and sealed with the end of tube T.
- the tube-end engaging structure 36 in turn supplies water to the interior of tube T.
- the hydroforming apparatus 10 further includes a lower water tank 90, which is connected to the tube-end engaging structure 38 via water line 92.
- a servo valve 94 disposed in the water line 92 controls flow of water from the tube-end engaging structure 38 to the lower tank 90.
- valve 84 is opened, and water flows from the upper tank 80, through tube-end engaging structure 36, through the tube T and into the tube-end engaging structure 38.
- a drain line 96 is connected from the lower die portion 16 to the lower tank 90. After a hydroforming operation, the drain line 96 drains any remaining water in the lower die portion 16 into the lower tank 90.
- a servo valve 98 is disposed in the drain line 96 to control the flow of water to the lower tank 90.
- water captured in the lower tank 90 is returned to the upper water tank 80 through return line 100.
- a simple positive displacement water pump 102 is disposed in the return line 100 to pump the water from the lower tank 90 to the upper water tank 80 through the return line 100.
- a servo valve 104 is disposed in the return line 100 to regulate the flow of fluid from the lower tank 90 to the upper water tank 80.
- the ram housing 32 of side ram assembly 28 houses the tube-end engaging structure 36 and a pressure-intensifiying structure 110.
- the tube-end engaging structure 36 comprises a main portion 112 and an end cap 114.
- the main protion includes a tubular sleeve protion 116 and a radially outwardly extending flange portion 118 extending radially outwardly from the rearward end of the sleeve portion 116.
- the outer peripheral edge 119 of the flange protion 118 is disposed in a slidably sealed relationship with a cylindrical inner side surface 120 of the ram housing 32.
- an outer cylindrical surface 122 of the sleeve protion 116 is disposed in sliding and sealed relation with a cooperating surface 128 generally defining an opening in the ram housing 32 through which the tube-end engaging structure 36 projects.
- the end cap 114 includes an annular flange protion 130 bolted and sealed by virtue of appropriate fasteners 132 to the circular distal end of the sleeve portion 116, which is disposed outwardly of the ram housing 32.
- the end cap 114 further includes an elongated tubular portion 134 integrally formed with the flange portion 130 and extending axially in an outward direction with respect to sleeve portion 116.
- the tubular portion 134 has a generally cylindrical exterior surface 136, which is constructed and arranged to form a peripheral seal with an arcuate upper die surface portion 138 of the upper die portion 14 and an arcuate lower die surface 140 of the lower die portion 16 when the upper die portion 14 is closed.
- the end cap 114 terminates in a nozzle portion 144 which projects outwardly from the tubular portion 134.
- the nozzle portion 144 is substantially tubular in shape, and is of a reduced outside diameter in comparison with the tubular portion 134.
- a radially extending annular flange portion 146 is disposed at the transition between the tubular portion 134 and the nozzle portion 144.
- the flange portion 146 is constructed and arrangd to engage in sealing relation with one end of a tube T disposed in the die structure 12 during a hydroforming operation.
- the nozzle portion 144 has a cylindrical exterior surface 148 constructed and arranged to be received within one end of the tube T. It may be preferable for the surface 148 to form an interference fit with the interior wall of the tube T at said one end.
- a longitudinal bore 150 extends through the end cap 114 and is constructed and arranged to communicate fluid from within the tube-end engaging structure 36 to the inner confines of the tube T.
- the pressure intensifying structure 110 has a generally disk-shaped base portion 160 having an annular outer periphery disposed in a slidably sealed relationship with the inner surface 120 of the ram housing 32.
- a solid cylindrical intermediate block portion 162 is integrally formed with base portion 160 and of decreased diameter in comparison with the base portion 160.
- a solid cylindrical forward portion 164 is integrally formed with intermediate portion 162 and is of decreased diameter in comparison with intermediate portion 162. Forward portion 164 extends from the intermediate block portion 162 into the inner confines of the sleeve portion 116 of the outer ram 36.
- the exterior surface of forward portion 164 has a generally cylindrical outer surface disposed in a slidably sealed relationship with the generally cylindrical cooperating interior surface of the sleeve portion 116.
- a radially extending annular flange surface 168 At the transition between the forward portion 164 and the intermediate block portion 162 is a radially extending annular flange surface 168.
- the flange surface 168 serves as a rearward stop for the tube-end engaging structure 36.
- Fig. 3 the tube-end engaging structure 36 and the pressure intensifying structure 110 are shown in their rearward-most positions within the ram housing 32.
- side ram assembly 30 is substantially identical to side ram assembly 28, with the exception of the connections to the lower tank 90 for the ram assembly 30 versus the connection to the upper tank 80 for the ram assembly 28.
- similar elements for the two ram assemblies 28 and 30 are given the same reference numerals.
- servo valve 46 is opened and hydraulic fluid is provided under pressure from the hydraulic pump assembly 22 through the fluid line 44 into an intermediate chamber 170 generally between the flange portion 118 of tube-end engaging structure 36 and the base portion 160 of pressure intensifying structure 110 in housing 32.
- servo valve 62 is opened so that hydraulic pump assembly 22 can provide hydraulic fluid through fluid line 56 into the intermediate chamber 170 in side ram assembly 30.
- servo valve 84 is opened to permit water flow from the upper water tank 80 through fluid line 82 into a pressure intensifying chamber 174 disposed within the confines of tube-end engaging structure 36, between innermost end of pressure intensifying structure 110 and the end cap 114.
- the fluid travels through the bore 150 of the tube-end engaging structure 36 into the tube T. and is subsequently communicated through the bore 150 in the opposite outer ram 38 into the forward chamber 174 of the outer ram 38.
- servo valve 94 is initially opened and hence permits fluid flow to the lower tank 90. With this flow of fluid through the tube T, substantially all air bubbles are purged from the tube T. Subsequently, the servo valve 94 is closed and tube T is pressurized to a predetermined extent.
- the upper die portion 14 is lowered onto the lower die portion 16 to form a closed die cavity 190, preferably having a boxed cross-sectional shape therebetween.
- the servo valve 84 connected with the tube-end engaging structure 36 and the servo valves 94 connected with the tube-end engaging structure 38 are closed.
- servo valves 48 and 60 are opened, and hydraulic fluid under pressure is provided by hydraulic pump assembly 22 through the hydraulic lines 42 and 54 to pressurize rearward chambers 194 disposed rearwardly of pressure intensifying structures 110 of the associated side ram assemblies 28 and 30.
- the fluid provided within the rearward chambers 194 causes movement of the pressure intensifying structures 110 inwardly toward one another so as to displace the water within the pressure intensifying chambers 174 through the fluid supplying outlets 150 and into the tube T.
- forced movement of the incompressible water contained in pressure intensifying chambers 174 into the tube T causes an initial diametrical expansion of the tube T.
- pressure intensifying structures 110 continue to be forced inwardly toward one another to displace the water in the pressure intensifying chambers 174 and further dametrically expand the tube T.
- the servo valves 46 and 62 remain open to permit pressurized hydraulic fluid to continue to flow from pump assembly 22 through hydraulic lines 44 and 56 to pressurize the intermediate chambers 170 of side ram assemblies 28 and 30. Fluid provided under pressure into the intermediate chambers 170 causes the tube-end engaging structures 36 and 38 to move longitudinally and inwardly toward one another and against the opposite ends of the tube T.
- Movement of the outer rams 36 and 38 in this fashion causes the metal material forming the tube T (preferably steel) to flow along the length of the tube so that the diameter of the tube can be expanded in some areas by 10 % or greater, while the wall thickness of the hydroformed tube T is maintained preferably within ⁇ 10 % of the wall thickness of the original tube blank.
- the metal material forming the tube T preferably steel
- fluid pressure between 2,000 and 3,500 atmospheres is used to expand the tube.
- pressures between 2,000 and 10,000 atmospheres, although even higher pressures can be used.
- pump 22 ceases to pressurize fluid lines 42, 44, 54 and 56. Then valves 50 and 58 are opened to permit hydraulic fluid flow under pressure from the hydraulic pump assembly 22 through the fluid lines 40 and 52. As a result, hydraulic fluid is provided under pressure to return chambers 200 disposed forwardly of the flange portion 118 of the tube-end engaging structure 36 and 38 as shown. Pressurization of the return chambers 200 drives the tube-end engaging structure 36 and 38 outwardly within the respective ram housings 32 and 34 so as to move the tube-end engaging structures 36 and 38 out of engagement with the opposite ends of the tube T, as shown in Fig. 8.
- valves 48, 46, 60 and 62 are open to permit back flow of hydraulic fluid into a hydraulic fluid reservoir contained in the hydraulic pump assembly 22.
- the side ram assemblies 28 and 30 of the present invention employ pressur intensifying structures 110 within tube-end engaging structures 36 and 38, there is no need to provide a separate, costly "intensifier" system for providing high internal pressures to expand the tube.
- intensifiers are normally required in high pressure hydroforming systems (i.e., hydroforming systems that utilize hydraulic expansion pressures greater than 2,000 atmospheres), and heretofore have been particularly required in high pressure hydroforming operations in which the opposite ends of a tube are engaged and forced inwardly to effect metal material flow along the length of the tube to replenish or maintain the wall thickness of the tube during expansion thereof.
- intensifiers have been used in conjunction with separate side ram members that are used only to push the opposite ends of the tube inwardly to effect the aforementioned material flow.
- the present invention accomplishes the same desired function as a hydroforming system having the conventional intensifier, but is much more cost-effective.
- water is fed under relatively low pressure, preferably by force of gravity (or a simple low pressure circulation pump), to the side ram assemblies.
- the side ram assemblies then utilize the same hydraulic power source (e.g., hydraulic pump 22) to exert the pressures that are required to expand the tube as well as the pressures that are required to force the opposite ends of the tube inwardly to retain the desired wall thickness.
- Another advantageous feature of the present invention is the use of the same hydraulic pump 22, used as aforementioned, to also apply the downward pressure to the upper die portion 14 when the upper die portion 14 is in its lowered position.
- the hydraulic pump 22 effects a downward force on the upper die portion 14 to oppose the internal die cavity pressure during tube pressurization and thus retain the upper die portion 14 in the lowered position.
- the final system is less complex and less cumbersome than the conventional system.
- FIG. 9-16 an enlarged partial view of a second embodiment of a hydroforming system is generally indicated at 220, in-accordance with the principles of the present invention.
- the preferred apparatus is comprised of five main assemblies: a frame assembly generally providing structural support and generally indicated at 222, an upper press assembly generally indicated at 224, a lower press assembly generally indicated at 226, a hydroforming die structure generally indicated at 228, and a hydraulic line assembly generally indicated a 230.
- the frame assembly 222 includes a pair of press side frame members 232 depicted as parallel laterally spaced elongate vertical members for mountin the upper press assembly 224 and lower press assembly 228.
- the upper ends of the side frame members 232 have a crown plate 234 mounted across the tops thereof.
- the crown plate 234 serves as support for parts of the hydraulic fluid system, to be described later.
- the upper press assembly 224 is configured as follows.
- a cylinder mount platen 236 is secured at its ends to the press side frame members 232.
- a ram cylinder 238 having a ram piston rod 240 that extends through a vertically disposed piston rod opening 242 in the cylinder mount platen 236.
- An upper portion of the piston rod 240 has an expanded outer diameter allowing the upper portion of the rod 240 to be disposed in sliding sealed engangement with interior surface of cylinder 238.
- a space defined by the upper portion of the piston rod 240 and the interior surfaces of the cylinder 238 define an upper pressure chamber 244.
- the piston rod diameter below the described upper end portion is slightly reduced and defines a lower pressure chamber 246 between the cylindrical, outer surface of the rod 240 and interior surfaces of the cylinder 238.
- the lower pressure chamber 246 is defined at its lower end by a radially inwardly extending portion of the base of the cylinder 238 and at ist upper end by the annular lower surface of the larger diameter upper portion of the piston rod 240.
- Fixedly secures to the lower end of the piston rod 240 is a pressure ram 248.
- the pressure ram 248 extends horizontally and does not quite span the lateral space between the two frame members 232.
- the lower press assembly 226 includes a press bed 250, a right outrigger 252 fixedly secured to the press bed 250 by a tie bolt 254, and a left outrigger 256 fixedly secured to the press bed 250 by means of another tie bolt 254.
- the press bed 250 supports a lower die half 260 and provides a foundation for other assemblies.
- the lower ends of the press side frame members 232 are securely fixed to the press bed 250 near the opposite ends of the bed 250.
- Fixedly secured to the lateral ends of the press bed and rising generally upwardly and laterally outwardly from the bed 250 are the right outrigger 252 and left outrigger 256 that provide support for hydraulically driven assemblies cylinders 274 and 292, which will be described below.
- the die structure 228 (which is enlarged in Fig. 16) is comprised of an upper die half 258 and a lower die half 260. Cylinders 274 and 292 are mounted on the aforementioned left and right outriggers.
- the die halves 258 and 260 have respective internal surfaces 264 and 270 that cooperate to define a die cavity 262 that defines the size and shape into which a tube blank is to be hydroformed.
- the top upper portion of the upper die half 258 is fixedly to the bottom of the press ram 248.
- the lower die half 260 is fixedly mounted on the press bed 250.
- the lower die half 260 is of the same general size and shape as the upper die half 258, but its internal die surface 264 is inverted relative to the lower die cavity surface 270. Disposed in the upper and lower die halves 258 and 260 are upper and lower tool nests or clamping structures 266 and 272 that cooperate to surroundingly clamp the exterior surface of tube blank T near each of its longitudinal ends and thereby secure the tube blank within the closed die.
- a fluid inlet 273 is disposed in one of the lower tool nests and will be described in greater detail later.
- a pair of hydraulically driven assemblies 274 and 292 Disposed along the axis of the die cavity and tool nests 266 and 272, and mounted beyond the press side frame members 232 on the outriggers 252 and 256, are a pair of hydraulically driven assemblies 274 and 292, aligned with said tube axis and directed toward the ends of the tube blank T.
- One of the cylinders 274, mounted on the left outrigger 256, is a lateral push cylinder.
- This cylinder 274 consists of a front member 276 and a rear member 278 that are secured to the top surface of the left outrigger 256, and a cylindrical wall member 280 secured between the front and rear members 276 and 278.
- the front member 276 has a central opening allowing sliding, sealed movement therethrough by a tube-end engaging structure 282.
- the rear end 281 of the tube-end engaging structure 282 is disposed withing the cylinder 274 and is of a diameter disposed in sliding sealed relation with the inside surface of the cylindrical wall member 280.
- the more forward portions of the tube-end engaging structure 282 are of less diameter than the described rear end portion, creating a lateral cylinder chamber 284 defined by the exterior cylindrical side surfaces of tube-end engaging structure 282, the cylindrical inside surface of the cylindrical wall member 280, the annular inwardly facing surface of the back end 281 of the tube-end engaging structure 282, and the annular rearwardly facing interior surface of the front member 276 of the cylinder 274.
- a rear pressurizing chamber 286 is defined by the forwardly facing, interior surface of the rear member 278 of the cylinder 274, the cylindrical wall member 280 and the back surface of the back end portion 281 of the tube-end engaging structure 282.
- a front end portion of the tube-end engaging structure 282 that protrudes beyond the front member 276 of the cylinder 274 is of slightly reduced diameter, and at the forward end of this front portion of the piston rod is a tube engaging portion in the form of a tapered nose section 288.
- the tapered nose section 288 is constructed and arranged to be received within the open end of a tube blank T to be hydroformed.
- the rearward portion of the tapered nose section 288 preferably has a radially outwardly extending annular flange (not shown) which abuts against the end edge of the tube blank T to enable nose section 288 to apply a substantial force against the tube end in the longitudinal tube direction.
- a relatively fine bore defining a fluid outlet 289 is formed through the nose section 288 and extends from an internal chamber 290 within the inwardly extending portion of tube-end engaging structure 282 to communicate fluid from chamber 290 into the tube blank T when the nose section 288 is engaged in a sealed relation with the end of bank T.
- the duplex cylinder assembly 292 has an inner wall 294 and an outer wall 296 fixed securely to the right outrigger 252.
- Disposed within the interior of the duplex cylinder assembly 292 is a hydraulically driven pressure intensifying structure 300 and a hydraulically driven tube-end engaging structure 304.
- the hydraulically driven pressure intensifying structure 300 has an outer end portion 299 disposed in slidingly sealed relation with an interior surface of cylindrical wall member 298 and a inwardly extending portion 303 having a relatively reduced diameter.
- the reduced diameter inwardly extending portion 303 of the pressure intensifying structure 300 passes in slidingly saeled relation through an opening formed in an annular cylinder divider 302 disposed about midway along the longitudinal axis of the cylindrical wall member 298.
- the hydraulically driven tube-end engaging structure 304 within the duplex cylinder assembly 292 is tubular and disposed inwardly of the cylinder divider 302.
- the tube-end engaging structure 304 has a rear end portion 311 movable in a slidably sealed relation with the inside surface of the cylinder wall 298.
- a main longitudinal cylindrical sleeve portion 309 having a reduced diameter extends inwardly through and moves in slidably sealed relation with an opening formed in the inner wall 294.
- a tube-end engaging portion in the form of a tapered nose portion 307 is defined on the innermost end of the cylindrical sleeve portion 309.
- the nose portion has a similar configuration to nose portion 288 as previously described.
- the inwardly extending portion 303 of the pressure intensifying structure 300, with high-pressure seals 301 secured to its innermost end, is slidingly mounted within the cylindrical sleeve 309 of the ram structure 304.
- the nose portion 307 has a relatively fine bore defining a fluid outlet 308 formed therethrough extending inwardly from the intensifier chamber 306 and opening through an innermost portion of the tapered nose portion 307 to enable the chamber 306 to fluidly communicate with the adjacent end of tube blank T.
- a pressurizing chamber 310 is defined between the rear end portion 299 of the hydraulically driven pressure intensifying structure 300 and the outer wall 296 of the duplex cylinder 292.
- a return chamber 312 is defined between the annular inwardly facing surface of the outer end portion 299 of the pressure intensifying structure 300 and the outwardly facing surface of the cylinder divider 302.
- a tube-end engaging structure pressure chamber 314 is formed between the inwardly facing surface of the cylinder divider 302 and the outwardly facing surface of the outer end portion 311 of the hydraulically driven tube-end engaging structure 304.
- a tube-end engaging structure return chamber 316 is defined around the cylindrical sleeve portion 309 of the tube-end engaging structure 304 and the inner wall 294 of the duplex cylinder assembly 292. These chambers have openings to fluid lines, as will be described below.
- the hydroforming assembly 220 illustrated in Figs. 9 to 16 includes a hydraulic line assembly 230 consisting of fluid lines, reservoirs, pumps and valves, as will be described in conjunction with the following description of operation of the invention.
- Figs. 9 and 10 show the hydroforming die assembly 228 in its open position. Referring particularly to Fig. 10, in the open position, the press ram 248 and upper die half 258 are raised. Hydroforming fluid 318, which is a combination of tap water and chemicals, is stored in a lower reservoir filter tank 320. This tank 320 has a float valve 322 that is connected to a water /chemical mixer via line 324 provided for evaporation and other fluid loss makeup. The fluid 318 is pumped through line 326 by a tank motor/water pump 328 to an upper gravity feed tank 330 which is mounted on the crown plate 234. An upper tank outlet line 334 is connected to tank 330. A shut-off valve 332 on line 334 is in the closed position in Figs. 9 and 10, allowing the upper gravity feed tank 330 to be filled via line 326.
- Hydroforming fluid 318 which is a combination of tap water and chemicals
- the hydroforming apparatus 220 includes a hydraulic fluid reservoir 338 that stores hydraulic fluid 336, preferably oil.
- a single hydraulic power source in the form of a high pressure hydraulic pump 340 draws the hydraulic fluid 336 through line 342, and then pumps the fluid 336 through line 344 to a control valve assembly 346 comprised of a plurality of valves (1-8).
- the valves No. 2 to No. 8 are shown in their closed position in Fig. 10. After fluid 336 passes through the control valve assembly 346, it returns to the hydraulic reservoir 338 via line 344, allowing the hydraulic pump and motor 340 to operate in a free wheel mode.
- the press ram 248 is in the open or raised position and is supported by the piston rod 240, ram cylinder 238 and the cylinder mount platen 236.
- the piston rod 240 is held in ist raised position by valve No. 1 being opened and hydraulic fluid 336 being pumped through line 348 into pressurizing chamber 246 within the press ram cylinder 238.
- valve No. 1 being opened and hydraulic fluid 336 being pumped through line 348 into pressurizing chamber 246 within the press ram cylinder 238.
- the tube blank T can be positioned on the lower tool nests 272 of the lower die half 260.
- Fig. 11 it can be seen that the level of hydroforming fluid 350 in tank 330 has been increased in comparison with Fig. 10 as a result of fluid having been pumped through line 326.
- the float valve 352 in the upper gravity feed tank 330 shuts off the water pump and motor 328 when the hydroforming fluid 350 has reached ist proper level.
- the hydraulic valve No. 1 of the control valve assembly 346 is a 3-way valve that closes to hydraulic fluid flow and opens to depressurize line 348.
- opening valve No. 1 prevents hydraulic back-pressure from building inside the chamber 246 during downward movement of the piston rod 240 by permitting trapped hydraulic fluid in chamber 246 to bleed back through line 348 and drain back to the hydraulic reservoir 338.
- the ram tube-end engaging structure 304 is activated by the opening of valve No. 7 to thereby allow hydraulic fluid to pass inwardly through line 381 and pressurize the tube-end engaging pressure chamber 314. This moves the tube-end engaging structure 304 toward one end of the tube blank T inside the closed die halves 258 and 260 to seal off the end of the closed die assembly while remaining spaced from the end on the tube blank T.
- the tube-end engaging structure 282 is activated by opening valve No. 4 to allow hydraulic fluid to flow through line 358 and into the pressurizing chamber 286. This forces the tube-end engaging structure 282 inwardly into the closed die halves 258 and 260 toward the opposite end of tube blank T.
- the tube-end engaging structure 282 moves forward to engage the inside diameter of the tube blank T with the tapered nose section 288 thereof and seal the adjacent end of the tube blank T.
- a valve 332 is opened and allows the hydroforming fluid 350 to flow quickly through line 334 under gravitational force form the gravity tank 330.
- the hydroforming fluid enters the closed die through an inlet 273 and floods the interior of the tube blank T internally.
- the tube-end engaging structure 304 moves inwardly and the tapered nose portion 307 engages the tube blank T to seal the hollow interior thereof.
- the water pump and motor 360 draws hydroforming fluid from the upper gravity tank 330 through line 362 and pumps it through a flex line 364 and a high pressure close-out valve 366.
- the hydroforming fluid travels into the intensifier chamber 306 from the close-out valve 366.
- pump and motor 360 is omitted, and hydroforming fluid travels from tank 330 to chamber 306 under force of gravity.
- the fluid is forced under low pressure from chamber 306 under force of gravity.
- the fluid is forced under low pressure from chamber 306 into the tube T through the fluid outlet 308 in the nose of the tube-end engaging structure 304.
- the high pressure seal 301 prevents the hydroforming fluid 350 from tank 330 from mixing with the hydraulic fluid 336 from tank 338.
- the hydroforming fluid that is forced through the fluid outlet 308, increases the pressure inside the tube blank T. This, in turn, evacuates or purges the air together with fluid carrying air bubbles inside the tube blank T through opening 289 of tube-end engaging structure 282. This mixture of fluid and air flows through the internal chamber 290 and into flexible high pressure hose connection sections 370 and 371. The hydroforming then passes through a high pressure close-out valve 372 and into the lower hydroforming fluid reservoir 320 via line 374. Valve Nor. 3 and 8 of the control valve assembly 346 open to prevent any hydraulic back pressure building inside chambers 316 and 284 of the right and left lateral push cylinders, respectively.
- valve No. 5 opens allowing high pressure hydraulic fluid to travel through line 376 into the intensifier chamber 310. This forces the intensifier piston rod 300 to extend into the intensifier chamber 306, compressing the hydroforming fluid through the opening 308 in the tube-end engaging lateral piston rod 304 and inside the tube blank T.
- Valve No. 7 again opens to supply pressure to the chamber 314 to forwardly force tube-end engaging piston rod 304.
- the opposing tube-end engaging structure 282 moves forward when valve No. 4 again supplies pressure to chamber 286 and forces the tube-end engaging structure 282 to push tube blank material T into the die cavity 262. Forcing the ends of tube blank T into the die cavity 262 creates flow of metal material inwardly so as to maintain the wall thickness of the tube as it is expanded.
- the wall thickness of the final part is preferably to remain within ⁇ 10 % of the wall thickness of the original blank.
- the opposing piston rods 304 and 282 continue to force tube blank material into the die cavity 262 while the forward portion 303 of intensifier piston rod 300 extends further into the intensifier chamber 306. This increases the pressure inside the intensifier chamber 306, forcing more hydroforming fluid inside the tube blank T through the opening 308 in the forward nose portion 307 of the main piston rod 304. The hydroforming fluid within the tube blank T reaches pressures of greater than 50,000 psi.
- the intensifier piston rod 300 continues to move forward until the tube blank T is completely formed against the cavity surfaces 264 and 270 of the hydroforming die cavity through a preset pressure. The lateral push on the ends of the tube blank T is maintained until the final shape of the desired part 200 has been achieved.
- Fig. 14 shows the intensifier chamber 306 reaching its preset pressure, meaning that the hydroforming cycle is complete.
- the intensifier piston rod 300 is retracted by the closing of valve No. 5 and the opening of valve No. 6 which forces hydraulic fluid into forward intensifier chamber 312, removing the extreme high pressure from the hydroforming fluid within the tube part.
- the lateral opposing tube-end engaging structure 282 retracts when valve No. 3 opens, permitting pump 340 to pressurize line 378 and chamber 284 of the push cylinder 274. This causes the tapered nose section 288 of the tube-end engaging structure 282 to move out of the end of the tube blank T.
- Three-way valve No. 4 is opened to depressurize line 358 and chamber 286 during retraction of tube-end engaging structure 282, so as to permit hydraulic fluid from chamber 286 to drain through line 344 into tank 338.
- valve No. 8 opens and pressurizes line 380 and chamber 316 of the cylinder 292. This causes the piston rod 304 to retract and remove the tapered surface 307 of the forward end of the piston rod 304 from the end of the tube blank T.
- the hydroforming fluid then drains from the tube blank T out of the die and into a press bed catch tray 382 where it is returned to the lower reservoir tank 320 through the drain line 374.
- Three-way valve No. 7 is opened to permit chamber 314 and line 381 to depressurize and drain through line 344 into tank 338 during retraction of piston 304.
- Valve No. 1 is activated to connect pump 340 with chamber 246 along line 348.
- Chamber 246 is pressurized to retract the press ram cylinder rod 240. This raises the press ram 248 and opens the die upper half 258, allowing the finished part 200 (hydroforming from the tube blank T) to be removed.
- the gravity feed valve 332 closes, allowing hydroforming fluid to be pumped back into the upper gravity feed tank 330 to start the next hydroforming cycle.
- Fig. 16 provides an enlarged longitudinal sectional view depicting the hydroforming operational stage illustrated in Fig. 15, and more clearly shows the parts of the die assembly 228.
- the part 200 has been formed and the die has been opened.
- the tube-end engaging structure may comprise only a single tube-end forcing component, with the opposing tube-end engaging component being a fixed component. This is in contrast to the previously-described embodiments, where the tube-end engaging structures comprise two moveable components that move toward one another.
- the pressure intensifying structure may provide high pressure fluid from only one end or from both ends of the tube part.
- the above-described invention reduces the initial cost to purchase the hydroforming equipment by as much as one-third. It also reduces operating and maintenance costs.
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- Shaping Metal By Deep-Drawing, Or The Like (AREA)
Abstract
Description
- The present invention relates to a hydroforming system which requires less capital investment to achieve high pressure hydroforming of tubular parts. In particular, the present invention relates to a replacement for the conventional, separate "intensifier" system for providing high internal pressures within the tubular blank to be expanded.
- Conventional hydroforming utilizes low pressure hydroforming fluid feed from a supply tank to supply hydroforming fluid for quick pre-filling of the tube blank after the die cavities have closed on the tube but prior to the axial cylinders engaging the tube blank into the cavity. As a result, a separate intensifier is necessary push the tube blank into the die cavity.
- Such a hydroforming press is known from US 3,350,905. It comprises a tube-end engaging structure movable to longitudinally compress a tubular blank, hydraulically driven by a dedicated pump and a hydroforming fluid supply system consisting of a low pressure pump for pre-filling the tube blank, a high pressure pump energizing a pressure multiplier and a conduit for adducting the hydroforming fluid from the external fluid supply system to one tube-end engaging structure. The high pressure pump further supplies pressure cylinders by means of a balancing cylinder in order to compensate the force applied by the pressurized hydroforming fluid on the tube-end engaging structure from within the tube blank. This system is not only costly, not the least by employing three pumps, but it also needs a sophisticated control system for balancing the transient forces of the hydroforming fluid within the tube blank and of the tube-end engaging structure. Deficiencies of this control system tend to either destroy the tube blank or loss of hydroforming fluid where the tube-end engaging structure joins the tube blank, the latter leading to incomplete deformation. A further drawback of this system resides in the distance for adducting the highly pressurized hydroforming fluid from the immobile pump and pressure multiplier to the longitudinally mobile tube-end engaging structure and from there to the inside of the tube blank. It is prown to leakage and limits the hydroforming pressure.
- The disadvantages of the prior art may be overcome by providing an apparatus which uses the hydroforming fluid from a tank to supply a relatively smaller amount of water to intensify the pressure within the tubular blank after it is sealed and is ready to be expanded. This smaller amount of water is supplied to a dual function cylinder used for pushing the tube blank into the die cavity as well as intensifying the fluid pressure inside the die cavity from one side of the tool. By replacing the current intensifiers with a dual function cylinder that supplies the hydraulic push to the tube blank and the internal fluid pressure for forming, the overall cost of the equipment is reduced substantially.
- In accordance with the present invention, water is fed under relatively low pressure to side ram or hydraulic cylinder assemblies which are used to expand the tubular blank. The side ram assemblies utilize the same hydraulic power source to exert the pressure that is required to expand the tube as well as the pressure that is required to force the opposite ends of the tube inwardly to retain the desired wall thickness of the resultant product. Thus, no separate intensifier is required.
- The present invention preferably also utilizes the same hydraulic power source to also apply the downward pressure to an upper die structure when the upper die structure is in ist lowered position to oppose the internal die cavity pressure during tube pressurization.
- It is a further object of the present invention to provide an apparatus for hydroforming a tubular metal blank that comprises a die structure, a hydroforming fluid source, a hydraulically driven tube-end engaging structure, a hydraulically driven pressure intensifying structure, and a single hydraulic power source. The tube-end engaging structure seals opposite ends of the tubular metal blank in said die cavity and is movable to longitudinally.
- In accordance with the present invention, an apparatus for hydroforming a tubular metal blank is provided, comprising a die structure, a hydroforming fluid source, a hydraulically driven tube-end engaging structure, and a hydraulically driven pressure intensifying structure. The die structure has an internal die surface defining a die cavity. The die cavity is constructed and arranged to receive the tubular metal blank. The hydroforming fluid source is disposed higher than the die cavity, and is constructed and arranged to provide hydroforming fluid internally to the tubular metal blank under the force of gravity. The hydraulically driven tube-end engaging structure engages and substantially seal opposite ends of the tubular metal blank in the die cavity. The tube-end engaging structure is movable to longitudinally compress the tubular metal blank. The tube-end engaging structure receives hydroforming fluid from the hydroforming fluid source and has a hydroforming fluid supplying outlet through which hydroforming fluid can be provided to an interior of the tubular metal blank. The hydraulically driven pressure intensifying structure is movable in response to hydraulic fluid pressure to pressurize the 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 the internal die surface. The hydraulically driven tube-end engaging structure is movable in response to hydraulic fluid pressure to enable the 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.
- The resultant system is much less complex, less cumbersome, and less expensive then conventionally known systems.
-
- Fig. 1 is a schematic view of a hydroforming press apparatus in accordance with the principles of the present invention;
- Fig. 2 is a schematic view similar to that shown in Fig. 1, but showing tube-end engaging structures moved into engagement with the opposite ends of the tube to be hydroformed;
- Fig. 3 is a schematic cross-sectional view of the hydraulic side ram assemblies and the die structure in accordance with the present invention;
- Fig. 4 is a view similar to that shown in Fig. 3, but showing the tube-end engaging structures of moved into engagement with the opposite ends of the tubular blank to be hydroformed;
- Fig. 5 is a view similar to that shown in Fig. 4, with the valve open to initiate pressurization of the tube to be hydroformed;
- Fig. 6 is a view similar to that shown in Fig. 5, but showing the initial pressurization of the tube to be hydroformed, and with the upper die structure in a lowered position;
- Fig. 7 is a view similar to that shown in Fig. 6, but shows the full expansion of the tubular blank and inward movement of the hydraulic side ram assemblies to maintain the wall thickness of the part being formed;
- Fig. 8 shows the subsequent step to that in Fig. 7 in which the outer rams are returned toward their original position within the side ram assemblies after a hydroforming operation;
- Fig. 9 is an enlarged schematic partial view of a second embodiment of a hydroforming press apparatus in accordance with the principles of the present invention, and showing the press in the open position;
- Fig. 10 is a schematic view of the complete hydroforming press apparatur partially embodied in Fig. 9, and showing the press in the open position;
- Fig. 11 is a schematic view similar to that shown in Fig. 10, but showing the press ram down and die closed;
- Fig. 12 is a schematic view similar to that shown in Fig. 11, but showing the side cylinders engaged and quick fill started;
- Fig. 13 is a schematic view similar to that shown in Fig. 12, but showing the side cylinders pushing inwardly on the tubular blank ends as fluid is being pressurized;
- Fig. 14 is a schematic view similar to that shown in Fig. 13, but showing an expanded hydroformed tube;
- Fig. 15 is a schematic view similar to that shown in Fig. 14, but showing the press ram up after competion of the hydroforming cycle; and
- Fig. 16 is an enlarged longitudinal sectional view generally depicting the die halves and laterally disposed cylinders depicted in Fig. 15.
-
- As shown in Fig. 1, the
hydroforming system 10 includes ahydroforming die structure 12, which includes anupper die portion 14 and alower die portion 16. Thelower die portion 16 is mounted on arigid base 18. - As can be appreciated from Fig.1, the
upper die portion 14 is carried by an upperhydraulic ram 20, which controls vertical movement of theupper die portion 14. More particularly, theupper ram 20 is hydraulically actuated to permit the weight of thedie portion 14 to move theupper die portion 14 vertically downwardly into cooperation with thelower die portion 16 at the beginning of a hydroforming operation. In addition, after theupper die portion 14 is lowered, theupper ram 20 applies a downward hydraulic force to theupper die portion 14 to maintain theupper die portion 14 in cooperative relation with thelower die portion 16 during high pressure conditions formed within the die cavity between the upper andlower die portions - A
hydraulic pump assembly 22 is constructed and arranged to provide hydraulic fluid under pressure to theupper ram 20 viahydraulic fluid line 24 to meintain theupper die portion 14 in cooperative relation with the lower die portion against the opposing force created by the high die cavity pressure conditions as aforesaid. Aservo valve 26 is disposed in thefluid line 24 to regulate fluid flow between thehydraulic pump assembly 22 and theupper ram 20. - The
hydraulic pump assembly 22 is also connected with a pair ofside ram assemblies structure 12. The side ram assemblies 28,30 includerespective ram housings engaging structures engaging structure 36 projects outwardly from theside ram housing 32, and the tube-endengaging structure 38 projects outwardly from theside ram housing 34. - As shown in Fig. 2, the tube-end
engaging structure 36 is movable inwardly from theram housing 32 and into engagement and sealing relation with one end of a tube T carried by thelower die portion 16. The tube-endengaging structure 38 is movable inwardly from theram housing 34 and is constructed and arranged to engage and seal the opposite end of the tube T. The tube-endengaging structure 36 will move inwardly and outwardly with respect to theram housing 32 based upon hydraulic fluid provided to theside ram assembly 28 by thehydraulic pump assembly 22 through three separatehydraulic fluid lines Servo valves fluid lines pump assembly 22 andside ram assembly 28. - In similar fashion, the
side ram assembly 30 is connected with thehydraulic pump assembly 22 for controlled movement of the tube-end engaging structure 38. Theside ram assembly 30 is connected with thehydraulic pump assembly 22 via three separatehydraulic fluid lines Servo valves fluid lines pump assembly 22 andside ram assembly 30. - The
hydroforming apparatus 10 further includes anupper water tank 80 constructed and arranged to hold a prescribed amount of water. Thewater tank 80 is connected viafluid line 82 to the tube-end engaging structure 36 ofside ram assembly 28. Aservo valve 84 is disposed in thefluid line 82 and controls water flow into the tube-end engaging structure 36 when it is engaged and sealed with the end of tube T. The tube-end engaging structure 36 in turn supplies water to the interior of tube T. - The
hydroforming apparatus 10 further includes alower water tank 90, which is connected to the tube-end engaging structure 38 viawater line 92. Aservo valve 94 disposed in thewater line 92 controls flow of water from the tube-end engaging structure 38 to thelower tank 90. - After the tube-
end engaging structures valve 84 is opened, and water flows from theupper tank 80, through tube-end engaging structure 36, through the tube T and into the tube-end engaging structure 38. - A
drain line 96 is connected from thelower die portion 16 to thelower tank 90. After a hydroforming operation, thedrain line 96 drains any remaining water in thelower die portion 16 into thelower tank 90. Aservo valve 98 is disposed in thedrain line 96 to control the flow of water to thelower tank 90. - After a hydroforming operation, water captured in the
lower tank 90 is returned to theupper water tank 80 throughreturn line 100. A simple positivedisplacement water pump 102 is disposed in thereturn line 100 to pump the water from thelower tank 90 to theupper water tank 80 through thereturn line 100. Aservo valve 104 is disposed in thereturn line 100 to regulate the flow of fluid from thelower tank 90 to theupper water tank 80. - The
hydroforming apparatus 10 will now be described in more detail in Fig. 3. As shown, theram housing 32 ofside ram assembly 28 houses the tube-end engaging structure 36 and a pressure-intensifiying structure 110. As shown, the tube-end engaging structure 36 comprises amain portion 112 and anend cap 114. More particularly, the main protion includes atubular sleeve protion 116 and a radially outwardly extendingflange portion 118 extending radially outwardly from the rearward end of thesleeve portion 116. The outerperipheral edge 119 of theflange protion 118 is disposed in a slidably sealed relationship with a cylindricalinner side surface 120 of theram housing 32. Similarly, an outercylindrical surface 122 of thesleeve protion 116 is disposed in sliding and sealed relation with a cooperatingsurface 128 generally defining an opening in theram housing 32 through which the tube-end engaging structure 36 projects. - The
end cap 114 includes anannular flange protion 130 bolted and sealed by virtue ofappropriate fasteners 132 to the circular distal end of thesleeve portion 116, which is disposed outwardly of theram housing 32. Theend cap 114 further includes an elongatedtubular portion 134 integrally formed with theflange portion 130 and extending axially in an outward direction with respect tosleeve portion 116. Thetubular portion 134 has a generally cylindricalexterior surface 136, which is constructed and arranged to form a peripheral seal with an arcuate upperdie surface portion 138 of theupper die portion 14 and an arcuatelower die surface 140 of thelower die portion 16 when theupper die portion 14 is closed. - The
end cap 114 terminates in anozzle portion 144 which projects outwardly from thetubular portion 134. Thenozzle portion 144 is substantially tubular in shape, and is of a reduced outside diameter in comparison with thetubular portion 134. A radially extendingannular flange portion 146 is disposed at the transition between thetubular portion 134 and thenozzle portion 144. Theflange portion 146 is constructed and arrangd to engage in sealing relation with one end of a tube T disposed in thedie structure 12 during a hydroforming operation. Thenozzle portion 144 has a cylindrical exterior surface 148 constructed and arranged to be received within one end of the tube T. It may be preferable for the surface 148 to form an interference fit with the interior wall of the tube T at said one end. - A
longitudinal bore 150 extends through theend cap 114 and is constructed and arranged to communicate fluid from within the tube-end engaging structure 36 to the inner confines of the tube T. - The
pressure intensifying structure 110 has a generally disk-shapedbase portion 160 having an annular outer periphery disposed in a slidably sealed relationship with theinner surface 120 of theram housing 32. A solid cylindricalintermediate block portion 162 is integrally formed withbase portion 160 and of decreased diameter in comparison with thebase portion 160. A solid cylindricalforward portion 164 is integrally formed withintermediate portion 162 and is of decreased diameter in comparison withintermediate portion 162.Forward portion 164 extends from theintermediate block portion 162 into the inner confines of thesleeve portion 116 of theouter ram 36. The exterior surface offorward portion 164 has a generally cylindrical outer surface disposed in a slidably sealed relationship with the generally cylindrical cooperating interior surface of thesleeve portion 116. - At the transition between the
forward portion 164 and theintermediate block portion 162 is a radially extendingannular flange surface 168. Theflange surface 168 serves as a rearward stop for the tube-end engaging structure 36. - In Fig. 3, the tube-
end engaging structure 36 and thepressure intensifying structure 110 are shown in their rearward-most positions within theram housing 32. - It should be appreciated that
side ram assembly 30 is substantially identical toside ram assembly 28, with the exception of the connections to thelower tank 90 for theram assembly 30 versus the connection to theupper tank 80 for theram assembly 28. Thus, in the figures, similar elements for the tworam assemblies - Operation of the system will now be described. As shown in Fig. 4, after the tube T is placed in the
lower die structure 16,servo valve 46 is opened and hydraulic fluid is provided under pressure from thehydraulic pump assembly 22 through thefluid line 44 into anintermediate chamber 170 generally between theflange portion 118 of tube-end engaging structure 36 and thebase portion 160 ofpressure intensifying structure 110 inhousing 32. Similarly,servo valve 62 is opened so thathydraulic pump assembly 22 can provide hydraulic fluid throughfluid line 56 into theintermediate chamber 170 inside ram assembly 30. When fluid is provided to theside ram assemblies end engaging structure flange portion 146 of each engage and seal the opposite ends of the tube T. - Next, as shown in Fig. 5,
servo valve 84 is opened to permit water flow from theupper water tank 80 throughfluid line 82 into apressure intensifying chamber 174 disposed within the confines of tube-end engaging structure 36, between innermost end ofpressure intensifying structure 110 and theend cap 114. The fluid travels through thebore 150 of the tube-end engaging structure 36 into the tube T. and is subsequently communicated through thebore 150 in the oppositeouter ram 38 into theforward chamber 174 of theouter ram 38. During this process of filling the tube T,servo valve 94 is initially opened and hence permits fluid flow to thelower tank 90. With this flow of fluid through the tube T, substantially all air bubbles are purged from the tube T. Subsequently, theservo valve 94 is closed and tube T is pressurized to a predetermined extent. - As shown in Fig. 6, after the tube T is filled with fluid, the
upper die portion 14 is lowered onto thelower die portion 16 to form aclosed die cavity 190, preferably having a boxed cross-sectional shape therebetween. - Upon lowering of the
upper die portion 14, theservo valve 84 connected with the tube-end engaging structure 36 and theservo valves 94 connected with the tube-end engaging structure 38 are closed. Subsequently,servo valves hydraulic pump assembly 22 through thehydraulic lines rearward chambers 194 disposed rearwardly ofpressure intensifying structures 110 of the associatedside ram assemblies rearward chambers 194 causes movement of thepressure intensifying structures 110 inwardly toward one another so as to displace the water within thepressure intensifying chambers 174 through thefluid supplying outlets 150 and into the tube T. As shown, forced movement of the incompressible water contained inpressure intensifying chambers 174 into the tube T causes an initial diametrical expansion of the tube T. - As shown in Fig. 7,
pressure intensifying structures 110 continue to be forced inwardly toward one another to displace the water in thepressure intensifying chambers 174 and further dametrically expand the tube T. Theservo valves pump assembly 22 throughhydraulic lines intermediate chambers 170 ofside ram assemblies intermediate chambers 170 causes the tube-end engaging structures outer rams - Most preferably, fluid pressure between 2,000 and 3,500 atmospheres is used to expand the tube. Depending upon the application, it may also be preferable to utilize pressures between 2,000 and 10,000 atmospheres, although even higher pressures can be used.
- After the tube T is formed into the desired shape, corresponding to the shape of the die cavity, pump 22 ceases to pressurize
fluid lines valves hydraulic pump assembly 22 through thefluid lines chambers 200 disposed forwardly of theflange portion 118 of the tube-end engaging structure return chambers 200 drives the tube-end engaging structure respective ram housings end engaging structures - As the tube-
end engaging structures ram housings flanges 118 engage the forwardly facing flange surfaces 168 of thepressure intensifying structures 110 and drive thepressure intensifying structures 110 outwardly. Eventually the pressure intensifying and tube-end engaging structures reach their original positions, as can be appreciated form a comparison between Figs. 3 and 8. - During this outward movement of the
pressure intensifying structures 110 and tube-end engaging structures valves hydraulic pump assembly 22. - After the tube-
end engaging structure drain line 96 past theopen servo valve 98 and into thelower tank 90. The water contained in thelower tank 90 is recycled to theupper tank 80 through thereturn line 100 when thewater pump 102 is activated. - Advantageously, because the
side ram assemblies pressur intensifying structures 110 within tube-end engaging structures - The present invention accomplishes the same desired function as a hydroforming system having the conventional intensifier, but is much more cost-effective. In the present invention, water is fed under relatively low pressure, preferably by force of gravity (or a simple low pressure circulation pump), to the side ram assemblies. The side ram assemblies then utilize the same hydraulic power source (e.g., hydraulic pump 22) to exert the pressures that are required to expand the tube as well as the pressures that are required to force the opposite ends of the tube inwardly to retain the desired wall thickness.
- Another advantageous feature of the present invention is the use of the same
hydraulic pump 22, used as aforementioned, to also apply the downward pressure to theupper die portion 14 when theupper die portion 14 is in its lowered position. Thehydraulic pump 22 effects a downward force on theupper die portion 14 to oppose the internal die cavity pressure during tube pressurization and thus retain theupper die portion 14 in the lowered position. In addition, the final system is less complex and less cumbersome than the conventional system. - Referring now to Figs. 9-16, an enlarged partial view of a second embodiment of a hydroforming system is generally indicated at 220, in-accordance with the principles of the present invention. The preferred apparatus is comprised of five main assemblies: a frame assembly generally providing structural support and generally indicated at 222, an upper press assembly generally indicated at 224, a lower press assembly generally indicated at 226, a hydroforming die structure generally indicated at 228, and a hydraulic line assembly generally indicated a 230.
- Referring particularly to Fig. 9, the
frame assembly 222 includes a pair of pressside frame members 232 depicted as parallel laterally spaced elongate vertical members for mountin theupper press assembly 224 andlower press assembly 228. The upper ends of theside frame members 232 have acrown plate 234 mounted across the tops thereof. Thecrown plate 234 serves as support for parts of the hydraulic fluid system, to be described later. - The
upper press assembly 224 is configured as follows. Acylinder mount platen 236 is secured at its ends to the pressside frame members 232. Generally centrally disposed on thecylinder mount platen 236 is aram cylinder 238 having aram piston rod 240 that extends through a vertically disposedpiston rod opening 242 in thecylinder mount platen 236. An upper portion of thepiston rod 240 has an expanded outer diameter allowing the upper portion of therod 240 to be disposed in sliding sealed engangement with interior surface ofcylinder 238. A space defined by the upper portion of thepiston rod 240 and the interior surfaces of thecylinder 238 define anupper pressure chamber 244. The piston rod diameter below the described upper end portion is slightly reduced and defines alower pressure chamber 246 between the cylindrical, outer surface of therod 240 and interior surfaces of thecylinder 238. Thelower pressure chamber 246 is defined at its lower end by a radially inwardly extending portion of the base of thecylinder 238 and at ist upper end by the annular lower surface of the larger diameter upper portion of thepiston rod 240. Fixedly secures to the lower end of thepiston rod 240 is apressure ram 248. Thepressure ram 248 extends horizontally and does not quite span the lateral space between the twoframe members 232. - The
lower press assembly 226 includes apress bed 250, aright outrigger 252 fixedly secured to thepress bed 250 by atie bolt 254, and aleft outrigger 256 fixedly secured to thepress bed 250 by means of anothertie bolt 254. Thepress bed 250 supports alower die half 260 and provides a foundation for other assemblies. The lower ends of the pressside frame members 232 are securely fixed to thepress bed 250 near the opposite ends of thebed 250. Fixedly secured to the lateral ends of the press bed and rising generally upwardly and laterally outwardly from thebed 250 are theright outrigger 252 and leftoutrigger 256 that provide support for hydraulically drivenassemblies cylinders - Referring further to the
hydroforming system 220 embodied in Fig. 9, the die structure 228 (which is enlarged in Fig. 16) is comprised of anupper die half 258 and alower die half 260.Cylinders internal surfaces die cavity 262 that defines the size and shape into which a tube blank is to be hydroformed. The top upper portion of theupper die half 258 is fixedly to the bottom of thepress ram 248. Thelower die half 260 is fixedly mounted on thepress bed 250. - The
lower die half 260 is of the same general size and shape as theupper die half 258, but itsinternal die surface 264 is inverted relative to the lowerdie cavity surface 270. Disposed in the upper and lower diehalves structures fluid inlet 273 is disposed in one of the lower tool nests and will be described in greater detail later. Disposed along the axis of the die cavity andtool nests side frame members 232 on theoutriggers assemblies - One of the
cylinders 274, mounted on theleft outrigger 256, is a lateral push cylinder. Thiscylinder 274 consists of afront member 276 and arear member 278 that are secured to the top surface of theleft outrigger 256, and acylindrical wall member 280 secured between the front andrear members front member 276 has a central opening allowing sliding, sealed movement therethrough by a tube-end engaging structure 282. Therear end 281 of the tube-end engaging structure 282 is disposed withing thecylinder 274 and is of a diameter disposed in sliding sealed relation with the inside surface of thecylindrical wall member 280. The more forward portions of the tube-end engaging structure 282 are of less diameter than the described rear end portion, creating alateral cylinder chamber 284 defined by the exterior cylindrical side surfaces of tube-end engaging structure 282, the cylindrical inside surface of thecylindrical wall member 280, the annular inwardly facing surface of theback end 281 of the tube-end engaging structure 282, and the annular rearwardly facing interior surface of thefront member 276 of thecylinder 274. Arear pressurizing chamber 286 is defined by the forwardly facing, interior surface of therear member 278 of thecylinder 274, thecylindrical wall member 280 and the back surface of theback end portion 281 of the tube-end engaging structure 282. Thesechambers end engaging structure 282 that protrudes beyond thefront member 276 of thecylinder 274 is of slightly reduced diameter, and at the forward end of this front portion of the piston rod is a tube engaging portion in the form of atapered nose section 288. Thetapered nose section 288 is constructed and arranged to be received within the open end of a tube blank T to be hydroformed. The rearward portion of the taperednose section 288 preferably has a radially outwardly extending annular flange (not shown) which abuts against the end edge of the tube blank T to enablenose section 288 to apply a substantial force against the tube end in the longitudinal tube direction. A relatively fine bore defining afluid outlet 289 is formed through thenose section 288 and extends from aninternal chamber 290 within the inwardly extending portion of tube-end engaging structure 282 to communicate fluid fromchamber 290 into the tube blank T when thenose section 288 is engaged in a sealed relation with the end of bank T. - On the opposite side of the
hdroforming press bed 250 and mounted securely to the top of theright outrigger 252 is a hydraulically drivenduplex cylinder assembly 292. Theduplex cylinder assembly 292 has aninner wall 294 and anouter wall 296 fixed securely to theright outrigger 252. Acylindrical wall member 298 secured between theinner wall 294 andouter wall 296 to define a cylinder chamber. Disposed within the interior of theduplex cylinder assembly 292 is a hydraulically drivenpressure intensifying structure 300 and a hydraulically driven tube-end engaging structure 304. The hydraulically drivenpressure intensifying structure 300 has anouter end portion 299 disposed in slidingly sealed relation with an interior surface ofcylindrical wall member 298 and a inwardly extendingportion 303 having a relatively reduced diameter. The reduced diameter inwardly extendingportion 303 of thepressure intensifying structure 300 passes in slidingly saeled relation through an opening formed in anannular cylinder divider 302 disposed about midway along the longitudinal axis of thecylindrical wall member 298. The hydraulically driven tube-end engaging structure 304 within theduplex cylinder assembly 292 is tubular and disposed inwardly of thecylinder divider 302. The tube-end engaging structure 304 has a rear end portion 311 movable in a slidably sealed relation with the inside surface of thecylinder wall 298. A main longitudinalcylindrical sleeve portion 309 having a reduced diameter extends inwardly through and moves in slidably sealed relation with an opening formed in theinner wall 294. A tube-end engaging portion in the form of atapered nose portion 307 is defined on the innermost end of thecylindrical sleeve portion 309. The nose portion has a similar configuration tonose portion 288 as previously described. The inwardly extendingportion 303 of thepressure intensifying structure 300, with high-pressure seals 301 secured to its innermost end, is slidingly mounted within thecylindrical sleeve 309 of theram structure 304. Defined inwardly of the high pressure seals 301 of thepressure intensifying structure 300 and within theram structure 304 is anintensifier fluid chamber 306. - The
nose portion 307 has a relatively fine bore defining afluid outlet 308 formed therethrough extending inwardly from theintensifier chamber 306 and opening through an innermost portion of the taperednose portion 307 to enable thechamber 306 to fluidly communicate with the adjacent end of tube blank T. - A pressurizing
chamber 310 is defined between therear end portion 299 of the hydraulically drivenpressure intensifying structure 300 and theouter wall 296 of theduplex cylinder 292. A return chamber 312 is defined between the annular inwardly facing surface of theouter end portion 299 of thepressure intensifying structure 300 and the outwardly facing surface of thecylinder divider 302. A tube-end engagingstructure pressure chamber 314 is formed between the inwardly facing surface of thecylinder divider 302 and the outwardly facing surface of the outer end portion 311 of the hydraulically driven tube-end engaging structure 304. A tube-end engagingstructure return chamber 316 is defined around thecylindrical sleeve portion 309 of the tube-end engaging structure 304 and theinner wall 294 of theduplex cylinder assembly 292. These chambers have openings to fluid lines, as will be described below. - The
hydroforming assembly 220 illustrated in Figs. 9 to 16 includes a hydraulic line assembly 230 consisting of fluid lines, reservoirs, pumps and valves, as will be described in conjunction with the following description of operation of the invention. - Figs. 9 and 10 show the hydroforming die
assembly 228 in its open position. Referring particularly to Fig. 10, in the open position, thepress ram 248 andupper die half 258 are raised.Hydroforming fluid 318, which is a combination of tap water and chemicals, is stored in a lowerreservoir filter tank 320. Thistank 320 has afloat valve 322 that is connected to a water /chemical mixer vialine 324 provided for evaporation and other fluid loss makeup. The fluid 318 is pumped throughline 326 by a tank motor/water pump 328 to an uppergravity feed tank 330 which is mounted on thecrown plate 234. An uppertank outlet line 334 is connected totank 330. A shut-offvalve 332 online 334 is in the closed position in Figs. 9 and 10, allowing the uppergravity feed tank 330 to be filled vialine 326. - The
hydroforming apparatus 220 includes ahydraulic fluid reservoir 338 that storeshydraulic fluid 336, preferably oil. A single hydraulic power source in the form of a high pressurehydraulic pump 340 draws thehydraulic fluid 336 throughline 342, and then pumps the fluid 336 throughline 344 to a control valve assembly 346 comprised of a plurality of valves (1-8). The valves No. 2 to No. 8 are shown in their closed position in Fig. 10. Afterfluid 336 passes through the control valve assembly 346, it returns to thehydraulic reservoir 338 vialine 344, allowing the hydraulic pump andmotor 340 to operate in a free wheel mode. - As stated previously, in Fig. 10 the
press ram 248 is in the open or raised position and is supported by thepiston rod 240,ram cylinder 238 and thecylinder mount platen 236. Thepiston rod 240 is held in ist raised position by valve No. 1 being opened andhydraulic fluid 336 being pumped throughline 348 into pressurizingchamber 246 within thepress ram cylinder 238. With theupper die half 258 raised, the tube blank T can be positioned on thelower tool nests 272 of thelower die half 260. - In Fig. 11 it can be seen that the level of
hydroforming fluid 350 intank 330 has been increased in comparison with Fig. 10 as a result of fluid having been pumped throughline 326. Eventually, thefloat valve 352 in the uppergravity feed tank 330 shuts off the water pump andmotor 328 when thehydroforming fluid 350 has reached ist proper level. The hydraulic valve No. 1 of the control valve assembly 346 is a 3-way valve that closes to hydraulic fluid flow and opens to depressurizeline 348. Also, opening valve No. 1 prevents hydraulic back-pressure from building inside thechamber 246 during downward movement of thepiston rod 240 by permitting trapped hydraulic fluid inchamber 246 to bleed back throughline 348 and drain back to thehydraulic reservoir 338. Valve No. 2 opens to line 354 and enables pump 340 to pressurize theupper chamber 244 of thepress ram cylinder 238. The pressram piston rod 240 moves downwardly and forces theupper die half 258 closed to clamp the tube blank T between diehalves chamber 244 of thepress ram cylinder 238 in maintained for the full hydroforming cycle until the tube is fully deformed. - In Fig. 12, the ram tube-
end engaging structure 304 is activated by the opening of valve No. 7 to thereby allow hydraulic fluid to pass inwardly throughline 381 and pressurize the tube-end engagingpressure chamber 314. This moves the tube-end engaging structure 304 toward one end of the tube blank T inside theclosed die halves end engaging structure 282 is activated by opening valve No. 4 to allow hydraulic fluid to flow throughline 358 and into the pressurizingchamber 286. This forces the tube-end engaging structure 282 inwardly into theclosed die halves end engaging structure 282 moves forward to engage the inside diameter of the tube blank T with the taperednose section 288 thereof and seal the adjacent end of the tube blank T. At the top of the system, avalve 332 is opened and allows thehydroforming fluid 350 to flow quickly throughline 334 under gravitational force form thegravity tank 330. The hydroforming fluid enters the closed die through aninlet 273 and floods the interior of the tube blank T internally. Subsequently, the tube-end engaging structure 304 moves inwardly and thetapered nose portion 307 engages the tube blank T to seal the hollow interior thereof. - The water pump and
motor 360 draws hydroforming fluid from theupper gravity tank 330 throughline 362 and pumps it through aflex line 364 and a high pressure close-outvalve 366. The hydroforming fluid travels into theintensifier chamber 306 from the close-outvalve 366. It should be appreciated that in another preferred embodiment, pump andmotor 360 is omitted, and hydroforming fluid travels fromtank 330 tochamber 306 under force of gravity. The fluid is forced under low pressure fromchamber 306 under force of gravity. The fluid is forced under low pressure fromchamber 306 into the tube T through thefluid outlet 308 in the nose of the tube-end engaging structure 304. Thehigh pressure seal 301 prevents thehydroforming fluid 350 fromtank 330 from mixing with thehydraulic fluid 336 fromtank 338. The hydroforming fluid that is forced through thefluid outlet 308, increases the pressure inside the tube blank T. This, in turn, evacuates or purges the air together with fluid carrying air bubbles inside the tube blank T through opening 289 of tube-end engaging structure 282. This mixture of fluid and air flows through theinternal chamber 290 and into flexible high pressurehose connection sections valve 372 and into the lowerhydroforming fluid reservoir 320 vialine 374. Valve Nor. 3 and 8 of the control valve assembly 346 open to prevent any hydraulic back pressure building insidechambers - In Fig. 13, the high pressure close-out
valves line 376 into theintensifier chamber 310. This forces theintensifier piston rod 300 to extend into theintensifier chamber 306, compressing the hydroforming fluid through theopening 308 in the tube-end engaginglateral piston rod 304 and inside the tube blank T. With the high pressure close-outvalves die cavity surfaces chamber 314 to forwardly force tube-end engagingpiston rod 304. This forces tube blank material T into thedie cavity 262. The opposing tube-end engaging structure 282 moves forward when valve No. 4 again supplies pressure tochamber 286 and forces the tube-end engaging structure 282 to push tube blank material T into thedie cavity 262. Forcing the ends of tube blank T into thedie cavity 262 creates flow of metal material inwardly so as to maintain the wall thickness of the tube as it is expanded. The wall thickness of the final part is preferably to remain within ± 10 % of the wall thickness of the original blank. - As can also be appreciated in Fig. 13, the opposing
piston rods die cavity 262 while theforward portion 303 ofintensifier piston rod 300 extends further into theintensifier chamber 306. This increases the pressure inside theintensifier chamber 306, forcing more hydroforming fluid inside the tube blank T through theopening 308 in theforward nose portion 307 of themain piston rod 304. The hydroforming fluid within the tube blank T reaches pressures of greater than 50,000 psi. - Referring to Fig. 14, the
intensifier piston rod 300 continues to move forward until the tube blank T is completely formed against the cavity surfaces 264 and 270 of the hydroforming die cavity through a preset pressure. The lateral push on the ends of the tube blank T is maintained until the final shape of the desiredpart 200 has been achieved. Fig. 14 shows theintensifier chamber 306 reaching its preset pressure, meaning that the hydroforming cycle is complete. - In Fig. 15, the
intensifier piston rod 300 is retracted by the closing of valve No. 5 and the opening of valve No. 6 which forces hydraulic fluid into forward intensifier chamber 312, removing the extreme high pressure from the hydroforming fluid within the tube part. The lateral opposing tube-end engaging structure 282 retracts when valve No. 3 opens, permittingpump 340 to pressurizeline 378 andchamber 284 of thepush cylinder 274. This causes the taperednose section 288 of the tube-end engaging structure 282 to move out of the end of the tube blank T. Three-way valve No. 4 is opened to depressurizeline 358 andchamber 286 during retraction of tube-end engaging structure 282, so as to permit hydraulic fluid fromchamber 286 to drain throughline 344 intotank 338. Corresponding events occur at the opposite end of the tube blank T when valve No. 8 opens and pressurizesline 380 andchamber 316 of thecylinder 292. This causes thepiston rod 304 to retract and remove the taperedsurface 307 of the forward end of thepiston rod 304 from the end of the tube blank T. The hydroforming fluid then drains from the tube blank T out of the die and into a pressbed catch tray 382 where it is returned to thelower reservoir tank 320 through thedrain line 374. Three-way valve No. 7 is opened to permitchamber 314 andline 381 to depressurize and drain throughline 344 intotank 338 during retraction ofpiston 304. Valve No. 1 is activated to connectpump 340 withchamber 246 alongline 348.Chamber 246 is pressurized to retract the pressram cylinder rod 240. This raises thepress ram 248 and opens the dieupper half 258, allowing the finished part 200 (hydroforming from the tube blank T) to be removed. Thegravity feed valve 332 closes, allowing hydroforming fluid to be pumped back into the uppergravity feed tank 330 to start the next hydroforming cycle. - Fig. 16 provides an enlarged longitudinal sectional view depicting the hydroforming operational stage illustrated in Fig. 15, and more clearly shows the parts of the
die assembly 228. In Figs. 15 and 16, thepart 200 has been formed and the die has been opened. - It should be appreciated that the present invention contemplates that the tube-end engaging structure may comprise only a single tube-end forcing component, with the opposing tube-end engaging component being a fixed component. This is in contrast to the previously-described embodiments, where the tube-end engaging structures comprise two moveable components that move toward one another.
- Similarly, the pressure intensifying structure may provide high pressure fluid from only one end or from both ends of the tube part.
- The above-described invention reduces the initial cost to purchase the hydroforming equipment by as much as one-third. It also reduces operating and maintenance costs.
- While the invention has been disclosed and described with reference to a limited number of embodiments, it will be apparent that variations and modifications may be made therein without departure from the spirit and scope of the invention. Therefore, the following claims are intended to cover all such modifications, variations, and equivalents thereof in accordance with the principles and advantages noted herein.
Claims (4)
- An apparatus for hydroforming a tubular metal blank comprising:a die strucure having an internal die surface defining a die cavity, said die cavatiy 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.
- An apparatus according to claim 1 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.
- An apparatus according to claim 2 wherein said hydroforming fluid is forced through said first path and through said second path under the force of gravity.
- An apparatus according to claim 3 wherein said second path comprises a pump for facilitating flow of hydroforming fluid to said tube-end engaging structure.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US4395097P | 1997-04-16 | 1997-04-16 | |
US43950P | 1997-04-16 | ||
EP98914753A EP0975448B1 (en) | 1997-04-16 | 1998-04-16 | High pressure hydroforming press |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP98914753A Division EP0975448B1 (en) | 1997-04-16 | 1998-04-16 | High pressure hydroforming press |
Publications (2)
Publication Number | Publication Date |
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EP1197274A1 true EP1197274A1 (en) | 2002-04-17 |
EP1197274B1 EP1197274B1 (en) | 2004-12-29 |
Family
ID=26152478
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP01127374A Expired - Lifetime EP1197274B1 (en) | 1997-04-16 | 1998-04-16 | High pressure hydroforming press |
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EP (1) | EP1197274B1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015162448A1 (en) * | 2014-04-21 | 2015-10-29 | Sumitomo Heavy Industries, Ltd. | Molding apparatus |
CN117415211A (en) * | 2023-12-19 | 2024-01-19 | 河北海航管道制造有限公司 | System for preparing inclined tee joint |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103464563B (en) * | 2013-09-13 | 2016-04-27 | 佛山市康思达液压机械有限公司 | The outer high-pressure liquid-filling building mortion of a kind of tubing |
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US3350905A (en) * | 1963-12-21 | 1967-11-07 | Agency Ind Science Techn | Liquid pressure bulge forming apparatus |
GB2057322A (en) * | 1979-08-28 | 1981-04-01 | Mannesmann Ag | Process and apparatus for the formation of hollow objects having varying cross section |
EP0439764A2 (en) * | 1990-02-02 | 1991-08-07 | EUROPA METALLI - LMI S.p.A. | Process for manufacturing hollow one-piece metal elements |
EP0497438A1 (en) * | 1991-01-28 | 1992-08-05 | MANNESMANN Aktiengesellschaft | Method and device to hydraulically expand tubular hollow profiles |
-
1998
- 1998-04-16 EP EP01127374A patent/EP1197274B1/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3350905A (en) * | 1963-12-21 | 1967-11-07 | Agency Ind Science Techn | Liquid pressure bulge forming apparatus |
GB2057322A (en) * | 1979-08-28 | 1981-04-01 | Mannesmann Ag | Process and apparatus for the formation of hollow objects having varying cross section |
EP0439764A2 (en) * | 1990-02-02 | 1991-08-07 | EUROPA METALLI - LMI S.p.A. | Process for manufacturing hollow one-piece metal elements |
EP0497438A1 (en) * | 1991-01-28 | 1992-08-05 | MANNESMANN Aktiengesellschaft | Method and device to hydraulically expand tubular hollow profiles |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015162448A1 (en) * | 2014-04-21 | 2015-10-29 | Sumitomo Heavy Industries, Ltd. | Molding apparatus |
CN106457345A (en) * | 2014-04-21 | 2017-02-22 | 住友重机械工业株式会社 | Molding apparatus |
US10531520B2 (en) | 2014-04-21 | 2020-01-07 | Sumitomo Heavy Industries, Ltd. | Molding apparatus |
CN117415211A (en) * | 2023-12-19 | 2024-01-19 | 河北海航管道制造有限公司 | System for preparing inclined tee joint |
CN117415211B (en) * | 2023-12-19 | 2024-02-23 | 河北海航管道制造有限公司 | System for preparing inclined tee joint |
Also Published As
Publication number | Publication date |
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EP1197274B1 (en) | 2004-12-29 |
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