Classifications

• • 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
  • B21D26/047—Mould construction
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
  • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
  • B21C37/15—Making tubes of special shape; Making tube fittings
  • B21C37/28—Making tube fittings for connecting pipes, e.g. U-pieces
  • B21C37/29—Making branched pieces, e.g. T-pieces
  • B21C37/294—Forming collars by compressing a fluid or a yieldable or resilient mass in the tube
• • 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
  • B21D26/037—Forming branched tubes
• • 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
  • B21D35/00—Combined processes according to or processes combined with methods covered by groups B21D1/00 - B21D31/00
  • B21D35/002—Processes combined with methods covered by groups B21D1/00 - B21D31/00
  • B21D35/008—Processes combined with methods covered by groups B21D1/00 - B21D31/00 involving vibration, e.g. ultrasonic
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S72/00—Metal deforming
  • Y10S72/71—Vibrating

Definitions

• the invention relates to a method for hydroforming a workpiece according to the preamble of patent claim 1 and a device for carrying it out according to the preamble of patent claim 11.
• a generic method or a generic device is known from DE 94 07 812.2 U1.
• a hollow profile forming the workpiece is inserted into an internal high-pressure forming tool that is divided along the extent of the hollow profile, after which it is closed.
• the hollow profile is then sealed at both ends by an axial ram.
• the interior of the hollow profile is filled using the axial plunger.
• the axial rams are fluidly connected to a pressure generator.
• An internal high pressure is then applied within the hollow profile by means of the pressure generator, as a result of which the latter is expanded until it bears against the wall of the tool engraving.
• the tool engraving has a branch which radially leads away from the hollow profile extension and into which the hollow profile material is displaced by the application of high internal pressure to form a neck.
• the material attaches to the branch wall.
• the widening process within the branch is stabilized by a counter slide which is displaceably guided in the branch and supports the necking in the end region.
• an additional axial force which is applied by retracting the axial punch, film material pushed to the branch point, whereby the thinning of the material responsible for the bursting in the branch area is at least partially compensated.
• the invention is based on the object of developing a generic method and a generic device in such a way that the process reliability in the internal high pressure forming of workpieces is improved.
• Thinning of material in the Form region is thus counteracted, a more favorable material distribution for the forming, in particular a more uniform wall thickness distribution being achieved and / or the degree of deformation being increased.
• a branch from the engraving ie when a neck is formed, this can mean an increase in the length of the pull.
• the process limits can thus be expanded, for example with regard to the production of secondary shaped elements.
• even narrower radii on the workpiece can be formed reliably without a crack occurring. All in all, the invention achieves an improved shaping of workpieces made of materials with low deformability. By partially decoupling the process parameters from the tribological conditions, higher process stability is achieved.
• the amplitude and frequency of the vibration must be adjusted accordingly, taking into account the workpiece material and the degree of forming of the shape to be achieved, i.e. the geometry of the finished formed workpiece or other relevant process parameters.
• the body vibration of the friction partners leads to a more even distribution of the lubricants when using lubricants on the surface of the workpiece, which leads to a further reduction in the friction. Due to the oscillating relative movement of the friction partners to one another and the activation of the introduced lubricant, static contact with simultaneous reduction of sliding friction is largely avoided, or the transition from static to sliding friction (stick-slip effect) is considerably reduced.
• FIG. 2 shows a device in accordance with the invention in a lateral longitudinal section, with a vibration exciter which is coupled to the workpiece,
• FIG. 4 shows a force-time diagram for the vibration-stimulating control of one of the friction partners with an average constant force curve.
• the device 1 shows a device 1 for expanding internal high pressure forming of a workpiece 2, which in this exemplary embodiment is formed by a hollow profile, but can also consist of two superimposed boards for the purpose of expanding the boards.
• the device 1 includes an réellehoch horru mold 3, which is divided into an upper tool 4 and a lower tool 5, which with their engravings 6 form the mold space 7 for the hollow profile 2 to be expanded.
• the upper tool 4 has a radial branch 8 which projects radially from the main direction of the molding space 7 and in which a counter-punch 9 of the device 1 which counteracts the internal high pressure within the hollow profile 2 is guided.
• the counter-punch 9 which is guided in a controllably controllable manner, serves to stabilize the material flow of the workpiece material when forming a neck 10 that conforms to the branch 8, and thus serves one Reliable molding at this point of the hollow profile 2, with the counter-punch 9 receding with increasing neck length.
• the upper tool 4 has a plurality of tool parts 11, 12 and 13, the tool part 11 forming a housing with an upper receiving space 14 open to the hollow profile 2, in which the two other tool parts 12 and 13, which are the sections of the section which are essential for the widening Engraving 6 include, are held movable relative to the hollow profile 2.
• the tool parts 12 and 13 are movable radially to the rectilinear section of the hollow profile 2.
• the tool part 13 which delimits the region of the branch 8 can be moved radially with respect to the neck 10 which is formed when internal high pressure is applied.
• the tool part 13 is slidably supported on a side wall 15 of the receiving space 14.
• the tool parts 12 and 13 are integrally connected to one another and can be displaced both radially to the straight part of the hollow profile 2 inserted into the forming tool 3 and axially to the latter and thus radially to the neck 10 of the hollow profile 2.
• the device 1 is shown in the drawing, its complete formation is to be presented mirror-symmetrically on the central axis 16.
• the lower tool 5 has a lower receiving space 17 which is open at the top and in which a tool part 18 of the lower tool 5, which essentially contains the lower engraving, is guided so that it can be moved.
• the hollow profile 2 is also sealed at both ends by a sealing stamp 19, which either remains rigid during its forming in its in-use position once it has been used, ensuring a tight metallic clamping connection between the hollow profile 2 and the sealing cone 20 of the sealing stamp 19, or which corresponds to that caused by the expansion of Hollow section 2 resulting axial shortening of the hollow section 2 is trackable. Sealing can also take place using a suitable radial seal instead of the sealing cone 20.
• the branch 8 of the forming tool 3 from the ends of the hollow profile 2 by additional application of an axial force to the hollow profile 2 by means of the sealing plunger 19, so that the process reliability the formation of the neck 10 can be further increased.
• the tool parts 11, 12, 13 and 18 can all be moved. Depending on requirements, these can also be arranged rigidly or only one or two tool parts can be moved.
• the tool parts 11, 12 and 13 all vibrate during the forming, but the tool part 11 which is guided along the tool parts 12 and 13 and oscillates radially to the hollow profile 2 is excited with a higher amplitude.
• This has the advantage that the frictional relief has a particularly strong effect on the re-pushing area located at the end of the hollow profile, so that the re-pushing of material there is made considerably easier and the areas of higher degrees of deformation such as the area of the necking 10 can be formed in a particularly reliable manner due to the increased material supply .
• the frictional relief for the remaining area of the engraving 6 is maintained due to the also vibrating tool parts 12 and 13.
• the hollow profile 2 After the hollow profile 2 has been inserted into the forming tool 3, the latter is closed, after which the sealing plungers 19 are moved into their sealing position of use.
• the counter-punch 9 is in its starting position with its end face 21 flush with the engraving 6 of the upper tool 4.
• a Sealing plunger 19 pressure fluid introduced into the hollow profile 2, after which the pressure fluid is stretched high by means of a high-pressure generation system which is fluidly connected to the feed bore. Due to the development of the internal high pressure, the hollow profile 2 expands, the walls of which lie against the engraving 6 of both the upper tool 4 and the lower tool 5.
• the counter-punch 9 is gradually retracted, the hollow profile material being displaced as a bubble into the expansion space which is released by the withdrawal of the counter-punch 9 by means of the internal high pressure. This bubble lengthens the further the counter-punch 9 is moved back, and lies against the wall of the branch 8 to form the neck 10.
• the hollow profile 2 When the hollow profile 2 rests on the engraving 6 or in the neck 10 on the wall of the branch 8, the hollow profile 2 forms a friction partner for the further shaping process with the shaping tool 3, since the hollow profile material for further shaping, i.e. for further flow to the forming point, the static friction on the forming tool to which it is pressed by the internal high pressure must be overcome. Since this frictional resistance runs counter to a reliable forming due to the thinning of the material on the hollow profile 2, it is the intention of the invention to reduce the friction and thus to increase the process reliability during the forming. At the same time, the process limits of internal high-pressure forming can also be extended without damage.
• the device 1 contains at least one body vibration exciter, which sets at least one friction partner in vibration during the forming process in such a way that a radial relative movement of the friction partners results in relation to one another, after which their abutment between the maxima 22 of the body vibration is canceled (FIGS. 3 and 4).
• the tool parts 11, 12, 13 and 18 can oscillate together or independently of one another with an oscillation frequency that is in the hertz or kilohertz range, but preferably in the range of 0 ⁇ v ⁇ 200 Hz, mechanically by means of a reciprocating piston as a vibration exciter that has a Eccentric drive is movable back and forth to be moved.
• the body vibration is initiated in the form of a longitudinal wave directed towards the hollow profile 2.
• the vibration exciter can also be a piezo element or a clocked electromagnet.
• the vibration exciter can be integrated into the forming tool 3 to save space.
• An acoustic excitation of the tool parts 11, 12, 13 and 18 is also conceivable.
• the counter-punch 9 can also be provided with such a vibration exciter, where the cap 24 of the neck 10 rests on the end face 21 of the counter-punch 9 due to the vibration is reduced.
• the device 1 additionally contains punch punches for punching holes on the circumference of the hollow profile 2 or shaping punches, for example when forming blanks, these can also be coupled to a vibration exciter.
• the vibration can be damped by means of a spring-damper system 25, which is supported in the lower tool 5 on the one hand on the bottom 26 of its receiving space 17 and on the other hand on the side 27 of the tool part 18 facing the bottom 26.
• this system 25 is supported on the top wall 28 of the receiving space 14 on the one hand and on the other hand on the facing sides 29, 30 of the tool parts 12 and 13.
• the locking force of the tool parts 11, 12, 13 and 18 swings back into their normal position during the forming process. It is conceivable that the locking force increases until the end of the process (FIG. 3) or remains constant during the entire process (FIG. 4).
• the oscillation can run as a pure sine oscillation 23 with flat amplitudes (FIG.
• the sawtooth shape and the rectangular pulses are advantageous for the method in that, because of the very steep flanks of the oscillation profiles, a spontaneous complete abolition of the system of the two friction partners can periodically be achieved, as a result of which the overall friction is reduced particularly strongly. It is also conceivable that the entire upper tool 4 and / or the entire lower tool 5 is excited to vibrate.
• a vibration to the friction partners is to excite the hollow profile 2 itself. This can be achieved via the sealing plunger 19, which is coupled to the vibration exciter on the one hand and in the sealing position of use to the workpiece, that is to say to the hollow profile 2.
• a reciprocating piston 32 with an eccentric drive 33 serves as the vibration exciter, the reciprocating piston 32 being coupled in a radial direction with the sealing plunger 19 so as to vibrate.
• a transverse wave thereby propagates in the hollow profile 2 along its shape, which also results in radially oscillating relative movements of the hollow profile 2 with the surrounding tool 3.
• a combination of the introduction of transverse waves into the hollow profile 2 and longitudinal waves into a tool part 12, 13 and 18 is also conceivable for a particularly strong lifting of the hollow profile 2 from the adjacent forming tool 3.
• the vibration excitation can also take place rotationally by introducing a torsional vibration if, as shown in FIG. 2, the friction partners, the hollow profile 2 and a tool part 34 of the forming tool 3, which comprises two half-shells, are rotationally symmetrical.
• the half-shells are held in the upper tool 4 and in the lower tool 5 in short circumferential grooves. While the tool part 34 directly in the circumferential direction by a few degrees of angle or even only parts of it can be driven back and forth quickly, the torsional vibration when introduced into the hollow profile 2 must be conveyed by the sealing stamp 19, which is driven by a rotary actuator forming the vibration exciter in accordance with the directions of the arrows.
• the excitation of the tool part 34 by a torsional vibration favors the pushing of hollow profile material out of the end region of the hollow profile 2 in a tool-technically simple manner, since the end region is closest to the excitation point of the remaining hollow profile 2 and is therefore detected most intensively. Due to the relatively small mass of the tool part to be actuated, no high travel and bearing forces are required. It is also possible to design the tool part 34 as a closed sleeve, which is inserted into corresponding recesses in the lower tool 5 before the shaping and through which the not yet deformed, straight hollow profile 2 is then passed. Then the upper tool 4 is lowered onto the lower tool 5 and thus the forming tool 3 is closed in order to follow the forming.
• vibration excitation of the friction partners can also take place through a combination of translational and rotary excitations.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)
• Forging (AREA)
• Pressure Welding/Diffusion-Bonding (AREA)
• Press Drives And Press Lines (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7879126

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (19)

Family Cites Families (10)

• 1998
  • 1998-08-28 DE DE19839353A patent/DE19839353C1/de not_active Expired - Fee Related
• 1999
  • 1999-07-10 DE DE59902483T patent/DE59902483D1/de not_active Expired - Fee Related
  • 1999-07-10 AT AT99932866T patent/ATE222822T1/de not_active IP Right Cessation
  • 1999-07-10 EP EP99932866A patent/EP1107837B1/fr not_active Expired - Lifetime
  • 1999-07-10 WO PCT/EP1999/004888 patent/WO2000012240A1/fr active IP Right Grant
  • 1999-07-10 US US09/763,973 patent/US6578400B1/en not_active Expired - Fee Related
  • 1999-07-10 ES ES99932866T patent/ES2181455T3/es not_active Expired - Lifetime
  • 1999-07-10 CA CA002342188A patent/CA2342188C/fr not_active Expired - Fee Related

Non-Patent Citations (1)

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