EP0940200A2 - Method and device for removing a slug from an internal high-pressure forming tool - Google Patents

Abstract

A method and a device for removal of a slug separated from a hollow profile by means of a fluidic internal pressure from a hydroforming tool. The slug is separated from the hollow profile from the inside to the outside by the retraction of a plunger integrated into the hydroforming tool and clearing a slug channel when retracted, and is forced out of the die cavity of the hydroforming tool into the slug channel. Then, with the hollow profile in a zero-pressure state, the slug, which after it is pressed in abuts the end of the plunger, is removed by a removal tool from the hydroforming tool. In order to remove slugs from the hydroforming tool in any desired position of the slug channel that leads into the die of the hydroforming tool, in which the slug is initially received after perforation, in simple fashion, the slug is held at the end of the plunger during its stay in the slug channel by an adhesion means connected with the plunger. Then, after the hydroforming tool is opened and the finished hollow profile is removed, the slug, while continuing to adhere to the end of the plunger, is guided by means of the plunger and of the removal tool designed with adhesion means into the open die cavity. The slug and the area of the removal tool on which the adhesion means acts assume a relative position opposite one another, after which the slug is separated from the plunger and then adheres to the removal tool, by means of which the adhering slug is then removed from the hydroforming tool.

Description

The invention relates to a method for removing a slug from an internal high pressure forming tool according to the preamble of claim 1 and a device for performing of the method according to the preamble of the claim 8th.

A generic method or a generic device is known from US 5,398,533. The device there includes an internal high pressure forming tool that runs along the extension of the hollow profile inserted into the engraving is. On the underlying flat surface of the cross section trapezoidal engraving is arranged in the recess an insert for punching the hollow profile under high internal pressure is introduced. The insert closes flush with the level Surface of the engraving and has an axial bore in the Stamp is performed. The bore has at its mouth a ring-shaped cutting edge for engraving. The stamp closes the mouth opening during the shaping of the hollow profile the hole. After completing the forming process, the stamp withdrawn relatively suddenly, after which under the influence of internal pressure still prevailing and due to the lack of Support of the hollow profile by the stamp the hollow profile is pressed against the cutting edge of the hole, whereupon this is cut out a slug, which is further in the perforated channel formed by the hole is pressed. The fluid pressure is then released and the stamp is removed lowered until the one on the face of the stamp Perforated slug at the level of the surroundings of the forming tool leading transverse channel to the hole-blanket channel, after which a removal tool designed as a slide the perforated slug out of the perforated slug channel through the transverse channel promoted to the outside. The stamp is otherwise mechanical by moving a ramp across the stamp which he is slidably arranged, driven by lifting. A disadvantage of the described embodiment of the perforated slug disposal, i.e. removal of the slug from the forming tool, is that they only occur when they are almost vertically down Perforations can be used, otherwise the perforated slug in the perforated channel of the use of the return movement cannot follow the stamp and therefore not from the slide can be conveyed out of the forming tool. Especially this concerns the execution of several perforations on the same Hollow profile in different circumferential areas. At a Release pressure only after reaching the height of the cross channel until then it falls to the face of the stamp due to internal high pressure pressed slugs from the stamp and on the underside the cutting edge of the insert.

The invention has for its object a generic To further develop a method and a generic device, that removing perforated slugs from the forming tool out of any position in the engraving of the Forming tool leading perforated channel in which the perforated slug after the perforation is initially recorded, in simpler Way becomes possible.

The task is according to the invention by the features of the claim 1 regarding the procedure and the characteristics of claim 8 solved with respect to the device.

Due to the adhesive on the stamp, the perforated slug can at any time i.e. both under the influence of high pressure as well in a relaxed state of the pressure fluid captive on the stamp are kept, the course and location of the perforated channel relative to the engraving of the forming tool for the It is completely irrelevant to hold the perforated slug on the stamp. For Removing the slug, it is convenient to do this on the part of the after forming, open mold space of the forming tool to do with the perforated hollow profile removed, since with several In contrast, perforations and thus several resulting slugs to the use required in the known method only one of several slide-like removal tools only removal tool is necessary to remove all the slugs to record. This simplifies the hydroforming tool quite significant since there are no cutouts for the slider and their Drives must be provided that match the strength of the forming tool are detrimental. Because of the adhesive property of the removal tool of the invention can that of the stamp pushed into the mold space and on its face still without falling off sticky slugs in the axial Push the removal tool into the mold space - no matter in the circumferential position of the slug - from the stamp detached and transferable to the removal tool, which then together with the slug from the forming tool is brought out. The adhesive area of the removal tool can be arranged on all sides in the circumferential direction be, which causes the transition of the hole blank from the stamp on the removal tool after a simple axial movement can. It can be adapted to the axial position of the stamp and thus the slug also several axially spaced Areas are provided, which are also on all sides in the circumferential direction act adherent. The adhesive area can also on the other hand, be locally concentrated, so that if necessary after the axial insertion of the removal tool around its own body Axis must be rotated with its sticking area to face the slug. Overall seen through the invention can be automated in a simple manner.

Fig. 1 in einem Querschnitt einen Lochstempel der erfindungsgemäßen Vorrichtung im Umformwerkzeug bei der Umformung eines Hohlprofiles mittels Innenhochdruck,

Fig. 2 in einem Querschnitt das Umformwerkzeug aus Fig. 1 mit zum Lochen des umgeformten Hohlprofiles durch Zurückziehen des Stempels unter Innenhochdruck,

Fig. 3 in einem Querschnitt das Umformwerkzeug aus Fig. 1 in Öffnungsstellung mit am Stempel erfindungsgemäß anhaftendem Lochbutzen,

Fig. 4 in einem Querschnitt das Umformwerkzeug aus Fig. 1 in Öffnungsstellung und Lage des Stempels aus Fig. 3 nach Entnahme des Hohlprofiles,

Fig. 5a in einem seitlichen Längsschnitt das Umformwerkzeug aus Fig. 1 mit in den geöffneten Formraum eingeschobenen Entnahmewerkzeug der erfindungsgemäßen Vorrichtung,

Fig. 5b einen Querschnitt von Fig. 5a,

Fig. 6a in einem Querschnitt das Umformwerkzeug aus Fig. 5a,b mit in den Formraum hineinstehendem Stempel,

Fig. 6b einen seitlichen Längsschnitt von Fig. 6a,

Fig. 7a in einem Querschnitt das Umformwerkzeug aus Fig. 6a,b mit vom Stempel gelöstem und am Entnahmewerkzeug anhaftendem Lochbutzen,

Fig. 7b einen seitlichen Längsschnitt von Fig. 7a,

Fig. 8a in einem Querschnitt das Umformwerkzeug aus Fig. 7a,b mit in den Lochbutzenkanal des Umformwerkzeuges zurückgezogenem Stempel,

Fig. 8b einen seitlichen Längsschnitt von Fig. 8a.

Expedient embodiments of the invention can be found in the subclaims; otherwise the invention is explained in more detail below with reference to two exemplary embodiments shown in the drawings; shows:

1 in a cross section a punch of the device according to the invention in the forming tool during the forming of a hollow profile by means of internal high pressure,

2 in a cross section the forming tool from FIG. 1 with for perforating the formed hollow profile by withdrawing the stamp under high internal pressure,

3 shows in a cross section the forming tool from FIG. 1 in the open position with the perforated slug adhering to the punch according to the invention,

4 in a cross section the forming tool from FIG. 1 in the open position and position of the stamp from FIG. 3 after removal of the hollow profile,

5a in a lateral longitudinal section the forming tool from FIG. 1 with the removal tool of the device according to the invention inserted into the opened mold space,

5b shows a cross section of Fig. 5a,

6a in a cross section the forming tool from FIG. 5a, b with the punch protruding into the molding space,

6b is a side longitudinal section of Fig. 6a,

7a in a cross section the forming tool from FIG. 6a, b with a perforated slug detached from the punch and adhering to the removal tool,

7b is a lateral longitudinal section of FIG. 7a,

8a in a cross section the forming tool from FIG. 7a, b with the plunger retracted into the perforated channel of the forming tool,

Fig. 8b is a side longitudinal section of Fig. 8a.

1 shows an internal high-pressure forming tool 1, in the mold space 2 enclosed by its engraving 10 Hollow profile 3 is inserted. The forming tool 1 is along the Extension of the hollow profile 3 in an upper tool 4 and Lower tool 20 divided into two. In the upper tool 4 there is a perforated channel 5 formed in which a stamp 6 can be moved is guided and its diameter corresponds to that of the channel 5. The stamp 6 closes flush with its end face 7 in FIG. 1 with the contour of the mold space 2. A stamp runs in 6 axially continuous channel 8, the side facing away from the molding space 9 is connected to the suction side of a pump and in the Face 7 of the stamp 6 opens into the mold space 2. In the first Method step (Fig. 1) for producing a perforated This becomes hollow profile by applying an internal high pressure on all sides according to the direction of the arrow until it engages with the engraving 10 expanded.

The stamp is now under continued high pressure 6 withdrawn according to FIG. 2 in the perforated channel 5, whereby this is released. This is due to the lack of support of the stamp 6 on the one hand and by the hydraulic internal high pressure on the other hand, the hollow profile 3 in the area of the mouth opening 11 of the perforated nozzle channel 5 out of the molding space 2 pressed into the channel 5, by pulling the Hollow profile material over the opening edge 12 of the mouth opening 11 a slug 13 from the hollow profile 3 from the inside to is sheared outside, which then up to the plant on the face of the stamp 7 pressed further into the perforated channel 5 becomes. The slug 13 is thus from the area of the molding space 2 separated.

It is advantageous to design the opening edge 12 as a cutting edge, so that the slug 13 clean from the hollow section 3rd is separated out. The hollow section 3 is also conceivable Inward movement of the stamp 6 in the mold space 2 under counteracting High pressure to stamp a predetermined breaking point what continues to favor the separation of the slug 13 with an essentially smooth slug edge.

Then the pump is started, which causes over the channel 8 affects a suction pressure on the slug 13, the thereby adhering to the stamp face 7. The suction pressure or of the hole 13 against the face 7 of the stamp 6 resulting negative pressure forms the adhesive of the stamp 6. It is beneficial to have the suction or vacuum before To build up the punching process so that the slug 13 is already one early date of the procedure on the stamp face 7 and thus a possible drop in pressure and escape of high pressure fluid avoided via the channel 8 of the stamp 6 becomes. At the same time, the vacuum supports the separation of the slug 13 on the side of the hollow profile facing away from the mold space 3rd

Finally, according to FIG. 3, the forming tool 1 after relaxation of the pressure fluid are opened, the perforated slug 13 due to its suction-related liability on the stamp 6 not down can fall into the open mold space 2. Then it will perforated hollow profile 3 removed from the open mold space 2 (Fig. 4).

5a, a removal tool designed as a rod is then used 14 for the slug 13 in the open mold space 2 introduced by means of a robot or manually. It can however, also the removal tool 14 first in the open mold space 2 are moved and only then the stamp 6 with the Perforated slugs 13 are inserted into the open mold space 2. The Removal tool 14 has a central axial channel 15, from the radial transverse channels 16 (Fig. 5b). The axial channel 15 is connected to the suction side of a pump, which is in operation in a similar way to the stamp 6 a suction pressure builds up. The removal tool 14 is axially in the mold space 2 positioned that the area with the orifices 17 of the Cross channels 16 of the opening 11 of the perforated nozzle channel 5 in about opposite.

Instead of several, only one radial transverse channel 16 can be used be formed, the removal tool 14 if necessary in addition to axial positioning, also around its body axis must be rotated until the mouth 17 of the Transverse channel 16 of the mouth opening 11 of the perforated nozzle channel 5 is opposite. Several thin channels 16 have the advantage that the suction of the pump via the axial channel 15 is a relatively large circumferential area of the removal tool 14 extends and thus created a circumferentially extended detention area becomes. Furthermore, the thin channels 16 ensure good adhesion for the slug 13 because with this configuration the suction pressure becomes high and therefore a good suction effect is achieved. As an alternative, training is one only channel with a large cross-sectional area 16 simple, but this configuration is less Has suction and only a limited effective adhesive surface, otherwise the slug 13 in the transverse channel 16 falls into it.

When the pump is operating, it is thus formed in the removal tool 14 negative pressure builds up the adhesive of the removal tool 14. After switching on the pump assigned to the removal tool creates a suction effect on the cross channels 16 on the there are perforated slugs 13 located in the perforated channel 5 conceivable here that the outgoing from the removal tool 14 Suction power versus the suction power of the stamp 6 connected Pump is so large that the slug 13 from the punch 6 detached away and drawn from the channel 5 onto the tool 14 is where he has a number of orifices 17 of the transverse channels 16 covers which orifices 17 span the area, which forms the point of detention of the slug 13. The adhesive effect of the removal tool 14 on the perforated slug 13 is by a negative pressure attacking at the detention point is generated.

This detachment process can be accelerated by switching off the stamp pump be, which reduces the performance of the pump of the removal tool 14 need not be particularly high. Nevertheless there is the possibility that the slug 13 in the slug channel 5 jammed when detaching from the stamp 6. This process uncertainty remedy, before the pump of the removal tool 14 shows its effect, the stamp 6 together with the perforated slug 13 still adhering to it from the perforated slug channel 5 move out into the mold space 2, so that jamming when detaching the slug 13 from the stamp face 7 is no longer possible and only a short distance from Removal tool 14 is (Fig. 6a, b). By reducing of the distance can be the suction force to be applied the removal tool pump can be reduced without detaching and losing adhesive effect.

The pump now develops its suction power. At the same time, the with the stamp 6 connected pump can be switched off, so that the adhesive force on the stamp is eliminated and only the suction force acts on the slug 13 via the removal tool 14, which closes most of the orifices 17 and due to the negative pressure building up on its underside 18 adheres to the outside 19 of the removal tool 14. Likewise, it is of course also conceivable that both pumps are in operation remain, the pump of the removal tool 14 a has greater suction than that of the stamp 6, so that the liability of the perforated slug 13 on the stamp 6 is lifted and this will become detached. Accordingly, this is from Removal tool 14 is tightened and remains on the tool 14 stick (Fig. 7a, b).

Around the removal tool 14 from the molding space 2 without hindrance to lead out with the adhering slug 13 and thus this To remove from the forming tool 1 is final 8a, b, the stamp 6 out of the molding space 2 into a Move back into the recessed position in position 5.

As an alternative to those based on suction or vacuum Adhesive of the stamp 6 and the removal tool 14 is conceivable, the stamp 6 and the removal tool 14 in rod form each form as an electromagnet. It is natural here mandatory that the hollow profile 3 and thus the perforated slug 13 made of a magnetic or magnetizable material consist. It is favorable for process security that Internal high-pressure forming tool 1 then from an unmagetic Material exists. Instead of the non-magnetic design of the Forming tool 1 can also be a shielding bushing in the perforated channel 5 be arranged, the force field of the stamp 6th keeps away from the surrounding magnetic forming tool 1.

The procedure with the electromagnet serving as an adhesive largely corresponds to that of the above and from the first embodiment shown in the figures, with the field of an electromagnet just as simple can be switched on like the pump for generating negative pressure. The slug 13 is attracted by the electromagnetic stamp 6 and remains there until it is replaced by the stronger one magnetic field of the electromagnetic extraction tool 14 be liable. It is advantageous when using electromagnets that the removal tool 14 has no defined axial relative position to take punch 6 or slug 13, because the attraction acts over its entire axial extent and is not limited to mouth openings 17.

Claims (13)

Method for removing a perforated slug separated from a hollow profile by means of a fluidic internal high pressure from an internal high-pressure forming tool, the perforated slug being separated from the inside with respect to the hollow profile by withdrawing a punch integrated in the forming tool and releasing a perforated channel during retraction and out of the forming space of the forming tool the perforated slug channel is pressed in, and in the depressurized state of the hollow profile, the perforated slug lying on the end face of the punch after pressing in is removed from the forming tool by means of a removal tool,
characterized,
that the perforated slug (13) is held on the punch face (7) during its stay in the perforated slug channel (5) by an adhesive bonded to the punch (6), and that after opening the forming tool (1) and removing the finished formed hollow profile (3) the perforated slug (13) with permanent adherence to the end face of the punch (7) by means of the punch (6) and the removal tool (14) designed with an adhesive is guided into the open mold space (2), the perforated slug (13) and the area of the Removal tool (14), in which the adhesive acts, take an opposite position relative to each other, after which the perforated slug (13) is detached from the stamp (6) and then adheres to the removal tool (14), by means of which the adhered perforated slug (13) is subsequently removed from the Forming tool (1) is led out. Method according to claim 1,
characterized,
that the perforated slug (13) initially adhering to the punch (6) from the removal tool (14) with a stronger force than the adhesion of the perforated slug (13) to the punch (6) with detachment of the perforated slug (13) from the punch (6) and subsequent Adhesion to the removal tool (14) is tightened. Method according to claim 2,
characterized,
that after the positioning of the stamp (6) in the molding space (2), the adhesive force of the adhesive of the stamp (6) acting on the perforated slug (13) is eliminated and at the same time the adhesive force of the removal tool (14) is built up. Method according to claim 1,
characterized,
that the perforated slug (13) is sucked in by a negative pressure which forms the adhesive and which is used to hold the perforated slug (13) on the punch (6) until it is detached. Method according to claim 1,
characterized,
that in the case of a perforated slug (13) consisting of a magnetic material, this is attracted by an electromagnet acting as an adhesive via the plunger (6), by means of which the perforated slug (13) is held on the plunger (6) until it is detached. Method according to claim 1,
characterized,
that the adhesive effect of the removal tool (14) is generated electromagnetically. Method according to claim 1,
characterized,
that the adhesive effect of the removal tool (14) is generated by a negative pressure acting on the later adhesive point of the slug (13). Device for removing a hollow slug separated from a hollow profile by means of a fluidic internal high pressure from an internal high pressure forming tool divided along the extension of the hollow profile, with a stamp integrated in the forming tool and guided in a perforated channel formed in it, on the front side of which the stamp is withdrawn by withdrawing the stamp from the hollow profile by means of the internal high pressure, there is a perforated slug which is separated outwards, and with a removal tool for removing the perforated slug lying against the punch from the forming tool in the depressurized state of the hollow section, for carrying out the method according to claim 1,
characterized,
that the stamp (6) is connected with an adhesive, by means of which the perforated slug (13) is held on the end face of the stamp (7), that the stamp (6) is open in the mold space (after forming and hollow profile-free opened forming tool (1)) 2) of the forming tool (1), and that the removal tool (14) can be moved into the open mold space (2) and has an adhesive, through which the perforated slug (13) in an open mold space (2) of the punch face (7) of the punch (6) located in the opposite position of the removal tool (14) is captively captive. Device according to claim 8,
characterized,
that the removal tool (14) is designed as a rod which has a central axial channel (15) from which at least one radial transverse channel (16) extends, the mouth opening (17) of the transverse channel (16) in the use position of the removal tool (14) in the open mold space (2) opposite the punch face (7), and that the axial channel (15) is connected to the suction side of a pump, the vacuum building up in the removal tool (14) forming the adhesive of the removal tool (14) during operation of the pump . Device according to claim 8,
characterized,
that in the case of a magnetic hollow profile material, the removal tool (14) is designed as a rod-shaped electromagnet, and that the internal high-pressure forming tool (1) consists of a non-magnetic material. Device according to claim 8,
characterized,
that an axially continuous channel (8) is arranged in the plunger (6), which is connected to the suction side of a pump on the side facing away from the mold space (9), the suction or negative pressure arising during operation of the pump being the adhesive of the plunger (6) forms. Device according to claim 8,
characterized,
that in the case of a magnetic hollow profile material, the stamp (6) is designed as an electromagnet, and that the internal high-pressure forming tool (1) consists of a non-magnetic material. Device according to claim 8,
characterized,
that in the case of a magnetic hollow profile material, the punch (6) is designed as an electromagnet, the force field of which is shielded from the surrounding forming tool (1).

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