EP2062987B1 - Heat form press - Google Patents

Description

The invention relates to a thermoforming press according to the features in the preamble of claim 1.

By the DE 24 52 486 C2 includes a method for producing a hardened sheet metal profile from a steel sheet in a prior art press hardening process. In this case, a board made of a hardenable steel is heated to hardening temperature, then hot formed in a press tool and then cured, while the sheet metal profile remains in the press tool. The steel sheet is pressed in less than 5 seconds in the final mold between two indirectly cooled tools under substantial change in shape and subjected to rapid cooling in the press so that a martensitic and / or bainitic fine-grained structure is achieved. Since the sheet metal profile is clamped in the press tool during cooling in the course of the curing process, a product with good dimensional stability is obtained.

The indirect cooling takes place via cooling channels, which are introduced in the form of holes or slots (shaft cooling) at a defined distance from the forming surface in the tool. Through these cooling channels flows a cooling medium, often water, that dissipates the heat given off by the warm metal profile to the tool to the outside. The cooling channels are usually drilled in the tool. The preparation of such holes is manufacturing technically complex and costly. The holes can often follow the three-dimensional structure of the tool surface only partially. As a result, the distance between the tool surface and the coolant channels is relatively large, whereby the cooling effect decreases.

Also the DE 10 2004 045 155 A1 Both the upper tool and the lower tool consists of a base plate with a fixed therein mold jaw and also set on the base plate, acting as a jaw core core. Between the support jaw and the back of the jaw facing the jaw, a channel system for the passage of a coolant is formed.

At the time of the DE 10 2005 028 010 B3 known press for thermoforming and press hardening of a high-strength sheet metal profile is the lower tool of the press within a liquid bath. Both parts of the mold geometry and the entire mold geometry can be below the liquid level. The sheet metal profile to be molded and hardened is placed above the liquid level and immersed in the liquid bath when the press is moved by the upper tool and deep-drawn into the lower tool.

A direct cooling in a thermoforming press is from the DE 26 03 618 A1 known. In the forming surface of the lower and upper tool concentric annular grooves are introduced, lead into the channels passed through the tools. Through these channels, a cooling liquid is fed into the annular grooves for direct contact with a sheet metal profile to be hardened. In this method, however, a relatively long process duration and a complex tool maintenance can be assumed. In general, a spray or dip cooling causes a strong contamination of the tools with coolant. This can cause corrosion and mechanical problems. The cooling performance leaves something to be desired.

The invention is based on the prior art based on the object to provide a plant and application technology improved thermoforming press for forming and hardening of metal sheets, with improved cooling effect and reduced process time.

The solution of this problem consists according to the invention in a thermoforming press according to the features of claim 1.

Thereafter, it is provided that the upper tool and / or the lower tool of the thermoforming press is constructed in two parts and includes a mold jaw and a support jaw. The shaping jaw and the support jaw are displaceable relative to one another, wherein the support jaw rests in a block position on the forming jaw and is spaced in a cooling position of the forming jaw, so that between the forming jaw and the support jaw, a cooling gap is formed through which a coolant is conductive.

In this way, a cooling system for the thermoforming press is provided, in which the distance between the coolant guide and the tool surface or the forming surface in the mold jaw can be minimized. As a result, the cooling can be ensured continuously during the forming process. Consequently, there is a minimum residence time of the pressed parts in the hot-forming press and thus a maximized economy.

Before the forming process are form jaw and jaw in the cooling position, so that coolant can flow through the cooling gap. As a result, the mold jaw and in particular its shape geometry is cooled. For the actual forming process, the cooling gap is closed and transferred the forming jaw and the jaw in the blocking position, in which the support jaw rests against the forming jaw. Supporting jaw and form jaw are virtually a unit. As a result, a sufficiently high tool stability is achieved during the forming process, which allows the transmission of high pressure pressures.

The thermoforming press is then closed and the metal sheet formed between the upper tool and lower tool to the sheet metal profile. After complete closing of the thermoforming press, the deformation of the metal sheet has taken place. The clamping force of the thermoforming press is only needed to maintain the contact between the produced sheet metal profile and the upper tool and the lower tool for the purpose of heat transfer during cooling or hardening process. In this state, the cooling gap between the forming jaw and the jaw is opened again. Coolant flows through the cooling gap over the entire surface and at a short distance from the warm component. As a result, optimal cooling can be achieved. Until the resealing of the thermoforming press, the cooling gap is maintained.

In principle, it is also possible to leave the shaping jaw and the supporting jaw in the blocking position during the hardening process, because the heat dissipation via the closed upper and lower tool is sufficient to carry out the hardening. It is only during the subsequent opening of the thermoforming press that the cooling gap is then opened in order to recool the upper or lower tool.

Advantageous embodiments of the basic concept of the invention are the subject of the dependent claims 2 to 8.

Preferably, the support jaw in the blocking position is positively against the forming jaw. The contacting surfaces of the jaw and form jaw are matched in their contour and correspond to each other.

In the cooling position, the cooling gap extends on the rear side of the shaping jaw facing the support jaw over the surface of the shape geometry of the shaping jaw.

For the displacement of the mold jaw and the jaw relative to each other linear drives are used: In principle, various embodiments of linear drives are possible. In practice, linear drives in the form of piston-cylinder units offer, in particular, this is intended to the use of hydraulic cylinders.

The supply of coolant into the cooling gap, as well as the discharge of the coolant from the cooling gap via coolant connections. These are preferably provided in the support jaw.

In order to prevent the escape of coolant through the movement or guide surfaces between the mold jaw and the jaw at least one seal is integrated between them. This is located in the opposite guide surfaces of the mold jaw and / or the jaw.

The seal is expediently provided in a groove in the support jaw above or below the coolant connection.

The shaping jaw preferably consists of a thin steel shell with a shape geometry designed in accordance with the component to be produced. Corresponding to this, the support jaw is shaped. The mold jaw has a wall thickness of 4 mm to 15 mm, preferably from 5 mm to 10 mm. Due to the comparatively thin wall thickness of the mold jaw, a good heat exchange between the coolant and the hot-formed component is possible.

Figur 1

im Schema in einem vertikalen Querschnitt eine erfindungsgemäße Warmformpresse in der Offenstellung mit geöffnetem Kühlkanal;

Figur 2

die Warmformpresse immer noch in geöffnetem Zustand jedoch mit geschlossenem Kühlkanal;

Figur 3

die Warmformpresse in der unteren Schließstellung beim Umformvorgang und

Figur 4

die Warmformpresse immer noch in der Schließstellung, jedoch mit geöffnetem Kühlkanal.

The invention is described below with reference to an embodiment shown in the drawings. Show it:

FIG. 1

in the diagram in a vertical cross section, a hot forming press according to the invention in the open position with open cooling channel;

FIG. 2

the thermoforming press still in the open state but with closed cooling channel;

FIG. 3

the thermoforming press in the lower closed position during the forming process and

FIG. 4

the thermoforming press is still in the closed position, but with the cooling channel open.

Based on Figures 1 - 4 a hot forming press 1 according to the invention is described. The illustrations each show schematically a vertical cross section through the thermoforming press 1 in different working positions.

The thermoforming press 1 essentially comprises an upper tool 2 and a lower tool 3. The lower tool 3 is arranged on a press base 4. The upper tool 2 is fixed to a press carriage 5, which is vertically displaceable in the thermoforming press 1 relative to the press base 4 and the lower tool 3.

Both the upper tool 2 and the lower tool 3 each have a forming jaw 6 and 7 and a support jaw 8 and 9, which are displaceable relative to each other. For this purpose, 9 linear drives 10 in the form of piston-cylinder units, in particular of hydraulic cylinders are connected between the mold jaw 6, 7 and the support jaw 8.

In a block position B, as in the Figures 2 and 3 can be seen, the support jaws 8, 9 are positively against each of the support jaw 8, 9 facing back 11, 12 of the mold jaws 6, 7 at. In block position B form the support jaw 8 and 9 and the mold jaw 6 and 7 so a massive unit.

In a cooling position K, the shaping jaws 6, 7 and the support jaws 8, 9 are arranged at a distance a from one another, so that a cooling gap 13 or 14 is formed between the shaping jaw 6, 7 and the support jaw 8, 9. Through the cooling gap 13, 14, a coolant KM can be passed.

The mold jaws 6, 7 each have a shape geometry 15, 16, which correspond to one another and is matched to the contour of a sheet metal profile to be formed. In the exemplary embodiment illustrated here, the shape geometry 16 of the forming jaw 7 of the lower die 3 forms a dome-like male part protruding from the base surface 17 of the forming jaw 7, which forms a receiving geometry (die) forming the same shape in the diametrically opposed, in relation to the base surface 18 of the shaping jaw 6 immersed during the forming process.

A shaping jaw 6 or 7 consists of a thin steel shell with a shape geometry 15, 16 formed in accordance with the component to be produced. The wall thickness s of the shaping jaw 6, 7 in the area of the shape geometry 15, 16 is consistently strong and preferably has a wall thickness s of 5 mm to 10 mm.

The supply and removal of coolant KM in the cooling gaps 13, 14 via coolant connections 19, 20, which are guided by the opposite the mold jaw 6, 7 wider side portions 21, 22. In the cooling position K, the coolant connections 19, 20 come into conductive connection with the cooling gaps 13 and 14, so that coolant KM can flow through the cooling gaps 13, 14.

It can be seen further that the mold jaws 6, 7 and the support jaws 8, 9 are sealed against each other via a respective seal 23. The seal 23 is integrated in a groove 24 in the mold jaw 6 and 7, respectively. The groove 24 is located above or below the coolant connections 19, 20.

Before the forming process of a metal sheet 25, the thermoforming press 1 is open and the upper tool 2 as well as the lower tool 3 are in the cooling position K. The cooling gap 13, 14 is open, so that a massive flow of coolant KM through the cooling gap 13, 14 allows is. The cooling gap 13, 14 extends on the back of the jaw 8, 9 facing back 11, 12 of the mold jaw 6, 7 over the surface of the mold geometry 15, 16 of the mold jaw 6, 7 and that with a small distance a, which the wall thickness s of the mold jaw 6, 7 in the area of the shape geometry 15, 16 corresponds to ( FIG. 1 ).

For forming the metal sheet 25, the cooling gap 13, 14 is closed and the mold jaws 6, 7 and the support jaws 8, 9 brought from upper tool 2 and lower tool 3 in the blocking position B ( FIG. 2 ).

In the thermoforming press 1 then heated to hardening temperature metal sheet 25 is inserted. Subsequently, the thermoforming press 1 is closed and the metal sheet 25 is formed into the sheet metal profile 26, as based on the FIG. 3 to recognize. When closing the thermoforming press 1, the press carriage 5 is moved together with the upper tool 2 down. In this case, the metal sheet 25 is pulled into the shape geometry 15, 16 and formed into the sheet profile 26.

After complete closing of the thermoforming press 1, the actual forming process of the metal sheet 25 is completed. The clamping force of the thermoforming press 1 is only needed to maintain the contact between the sheet metal profile 26 and the upper tool 2 and the lower tool 3. In this phase, the cooling gaps 13, 14 are opened again ( FIG. 4 ). The mold jaws 6, 7 and the support jaws 8, 9 are again in the cooling position K and coolant KM flows over the entire surface and at a short distance a to the hot-formed sheet metal profile 26 through the cooling gaps 13, 14. Due to the small distance a between the hot sheet metal profile 26th and the coolant KM and the full-surface coolant entry is a very good heat dissipation from the sheet metal profile 26 and thus achieves an efficient cooling or hardening process.

After completion of the curing process, the thermoforming press 1 is opened again. This is done with the cooling gap 13, 14 open so that the mold jaws 6, 7 are further cooled. The finished shaped and hardened sheet metal profile 26 can be removed from the thermoforming press 1 and begin the forming process anew.

Reference numerals:

1 -

Thermoforming press

2 -

upper tool

3 -

lower tool

4 -

Press base

5 -

press slide

6 -

forming jaw

7 -

forming jaw

8th -

supporting cheek

9 -

supporting cheek

10 -

linear actuator

11 -

Backside v. 6

12 -

Backside v. 7

13 -

cooling gap

14 -

cooling gap

15 -

shape geometry

16 -

shape geometry

17 -

Base area v. 7

18 -

Base area v. 6

19 -

Coolant connection

20 -

Coolant connection

21 -

Page area v. 6, 7

22 -

Seitenberich v. 6, 7

23 -

poetry

24 -

groove

25 -

metal sheet

26 -

metal profile

B -

block position

K -

cooling position

KM -

coolant

a -

distance

s -

Wall thickness v. 6 or 7

Claims (8)

1. Hot moulding press for forming and hardening sheet metal with an upper die (2) and a lower die (3), wherein at least one of the dies (2; 3) encompasses a moulding jaw (6; 7) and a supporting jaw (8; 9) and a coolant (KM) can be conducted between the moulding jaw (6; 7) and the supporting jaw (8; 9), characterised in that the moulding jaw (6; 7) and the supporting jaw (8; 9) are displaceable relative to one another, wherein
   the supporting jaw (8; 9), in a blocking position (B), adjoins the moulding jaw (6; 7) and, in a cooling position (K), is spaced apart from the moulding jaw (6; 7) so that a cooling gap (13; 14) is formed between the moulding jaw (6; 7) and the supportingjaw (8; 9).
2. Hot moulding press according to Claim 1, characterised in that the supporting jaw (8; 9), in the blocking position (B), adjoins the moulding jaw (6; 7) in a positive-locking manner.
3. Hot moulding press according to Claim 1 or 2, characterised in that the cooling gap (13; 14) extends across the surface of the moulding geometry (15; 16) of the moulding jaw (6; 7) on the rear side (11; 12) of the moulding jaw (6; 7) facing the supporting jaw (8; 9).
4. Hot moulding press according to one of Claims 1 to 3, characterised in that the moulding jaw (6; 7) and the supporting jaw (8; 9) can be displaced relative to one another by means of linear drives (10).
5. Hot moulding press according to Claim 4, characterised in that the linear drives (10) are piston/cylinder units which are inserted between the moulding jaw (6; 7) and the supporting jaw (8; 9).
6. Hot moulding press according to one of Claims 1 to 5, characterised in that coolant connections (19, 20), which, in the cooling position (K), come into conducting connection with the cooling gap (13; 14), are provided in the moulding jaw (6; 7).
7. Hot moulding press according to one of Claims 1 to 6, characterised in that the moulding jaw (6; 7) and the supporting jaw (8; 9) are sealed off from one another by means of at least one seal (23).
8. Hot moulding press according to one of Claims 1 to 7, characterised in that the moulding jaw (6; 7) has a wall thickness (s) of 4 - 15 mm, in particular of 5 - 10 mm.

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