EP2309008A2 - Device for producing hardened steel components - Google Patents

Abstract

The apparatus for producing hardened steel components, comprises tool halves (1, 2), which possess cooling jaws (3) having a rear side for binding the cooling jaw on a tool base body (12, 13) and an external molded surface (5, 6), whose contour corresponds to a contour of the metal sheet component to be hardened, where cylindrical holes (16) are arrangeably introduced from the rear side. The holes extend to the contour of the molded surface with optionally different depths in the cooling jaws. The apparatus has heat conducting tubes extending over the rear side. The apparatus for producing hardened steel components, comprises tool halves (1, 2), which possess cooling jaws (3) having a rear side for binding the cooling jaw on a tool base body (12, 13) and an external molded surface (5, 6), whose contour corresponds to a contour of the metal sheet component to be hardened, where cylindrical holes (16) are arrangeably introduced from the rear side. The holes extend to the contour of the molded surface with optionally different depths in the cooling jaws. The apparatus has heat conducting tubes extending or variably protruding over the rear side in same height. The heat conducting tubes are variably long. The apparatus has an adjustment unit, which is actively formed to the heating conducting tubes and/or movably or extractably formed to the individual heating conducting tube or groups of heating conducting tubes from the holes. A seal is disposed in the area of the hole opening in the rear side of the cooling jaw and outwardly seals the hole with the heating conducting tube. A water casing or a cooling liquid-guiding hollow body is arranged in the tool base body, where the heat conducing tubes extend into the water casing or the cooling liquid-guiding hollow body. The water casing or the tool base body has holes in the areas adjacent to the cooling jaws, where the areas are engaged by the heat conducting tubes, so that the heat conducting tubes extend into the water casing or the hollow body. The contour of the molded surfaces is formed, so that a metal sheet component arranged between the molded surfaces is completely kept in closed state of the tool.

Description

The invention relates to a device for producing hardened steel components.

It is known to first austenitise boards of a hardenable steel sheet at high temperature by the so-called press-hardening, then to transfer the board into a die and to pull it deeply into this die when hot. In this matrix, the large temperature difference between the die and steel sheet and the high heat capacity of the die simultaneously cools the steel sheet very strongly, cooling at a rate above the critical hardening speed. This means that the deep drawn in the die component is cured simultaneously.

This method has been partially refined, so that it is also known to first cold form a blank from a steel sheet and then heat the component produced by the cold forming to a temperature necessary for austenitizing and then the heated component in a so-called form hardening tool transfer, wherein the mold hardening tool consists of a Werkzeugober- and a lower tool part, which have the contour of the finished component. In this mold hardening tool is the heated Component inserted and held only during the rapid cooling and thereby hardening, but not transformed.

Moreover, it is known to equip such molds or dies with a water cooling to ensure that even at high cycle rates, the tool has such a low temperature that cooling of the heated workpieces is guaranteed at a speed above the critical speed.

Such water-cooled forms have proven in principle. However, such water-cooled forms consist of so-called cooling shells, which serve to cool the component, and a mold body lying behind it, wherein there are water-conducting grooves between the cooling shells and the mold body. On the one hand, this means that the grooves must be milled three-dimensionally in accordance with the contour of the cooling shell and thus of the desired component. These cooling shells must then be manually faded in order to ensure the tightness and power transmission on the bearing surfaces of the underlying mold body, the generation of Tuschierbilder is very complex. In addition, the sealing of the cooling shells is complex. If no shells with grooves are provided, cooling jaws with deep holes or cast-in pipes must be provided.

In case of changes, this leads to reworking in all cases. In addition, the cooling performance of clogged deep hole drilling and cast-in pipes and also in the grooves due to deposits and inaccessibility can be reduced.

The object of the invention is to provide a device for producing hardened steel components, which can be produced in a simple manner, even at high clock rates reliable one causes strong cooling and curing of the heated components and their cooling capacity is zonal changeable to affect the component properties.

The object is achieved with a device having the features of claim 1.

Advantageous developments are characterized in the subclaims.

The device according to the invention for producing hardened steel components comprises a tool with two mold halves, wherein each mold half has a cooling jaw which has an outer mold surface whose contour essentially corresponds to the contour of a sheet metal component to be hardened. The cooling jaw also has a back, which serves to connect the cooling jaw to the rest of the mold half. However, in contrast to the prior art, this rear side does not have the contour of the front side, but is flat in the simplest case. In this back a plurality of cylindrical bores is formed. In these holes so-called heat pipes or heat pipes are inserted, which essentially take over the cooling, the heat pipes can be either sunk completely buried in the holes or beyond the back and can protrude into a cavity in the rest of the mold half, which, for example, of water is flowed through. Hereby, the cooling performance of the heat pipes can be improved, with the seal and connection is considerably easier than in the prior art.

Heat pipes or heatpipes are heat exchangers that allow a high heat flux density, ie on a small cross-sectional area using heat of vaporization of a substance can dissipate large amounts of heat. The thermal resistance of such heat pipes is much smaller than that of metals.

Heat pipes consist of an encapsulated cavity, which is tubular and filled with a working fluid. This working medium fills the cavity both in the liquid and vapor state, each located opposite a heat transfer surface for heat source and heat sink.

When heat enters the working medium begins to evaporate, whereby the pressure is increased locally, resulting in a low pressure gradient within the heat pipe. The resulting vapor flows towards the condenser, where it condenses because of the low temperature. Here, the heat absorbed is released again, the now liquid working medium returns by capillary force back to the evaporator.

The use of heat pipes or heat pipes is known from a wide technical field, wherein from the CA 2,271,099 Also, the application is known in a plastic mold, which is made by electroforming, wherein in the electroforming the heat pipes are integrally formed in the mold.

In the invention it is advantageous that a simple and reliable cooling is achieved even in the mechanically extremely highly stressed molds for hardening sheet steel components. If the heatpipes are no longer needed in certain areas, they can simply be removed and, if necessary, the holes can be filled in a simple manner - in contrast to conventionally flowed through deep hole bores. For example, by inserting corresponding rods from the base material and / or welding.

Figur 1:

eine erfindungsgemäße Vorrichtung in einer stark schematisierten Querschnittsdarstellung;

Figur 2:

eine Vorrichtung nach Fig. 1 mit steuerbaren Wärme- leitrohrgruppen zur Beeinflussung der Materialeigen- schaften;

Figur 3:

die Vorrichtung nach Fig. 1 mit einer Variation der Wärmeleitrohrdurchmesser und Einstecktiefen;

Figur 4:

ein Ausschnitt einer Vorrichtung nach Fig. 1 mit ei- ner Wärmeleitrohrdichtung.

The invention will be explained with reference to a drawing. It shows:

FIG. 1:

a device according to the invention in a highly schematic cross-sectional representation;

FIG. 2:

a device after Fig. 1 with controllable heat-conducting tube groups for influencing the material properties;

FIG. 3:

the device after Fig. 1 with a variation of the Wärmeleitrohrdurchmesser and insertion depths;

FIG. 4:

a section of a device after Fig. 1 with a heat pipe seal.

The device according to the invention ( Fig. 1 ) has two tool halves 1, 2, wherein an upper mold half 1 an upper cooling jaws 3 and the lower mold half 2 has a lower cooling jaws 4. The cooling jaws each have an outer mold surface 5, 6, which respectively correspond to the contour of a sheet metal component to be hardened 7, wherein, for example, the contour of the mold surface 5 of the upper cooling jaw 3 corresponds to an outer surface 8 of the sheet metal component and the contour of the mold surface 6 of the lower cooling jaw 4 of Contour of an inner side 9 of the sheet metal component 7 corresponds. In particular, the shaping surfaces 5, 6 have corresponding contours.

The cooling jaws 3, 4 each have a substantially flat rear side 10, 11.

In addition, the tool halves 1, 2 each have a tool base body 12, 13, wherein the tool body a flat Anbindungsfläche 14, 15 have, which are facing the cooling jaws 3, 4 and with which each a cooling jaws 3, 4 on the tool base bodies 12, 13 can be connected.

From the rear sides 10, 11 forth in the cooling shells, a plurality of cylindrical bores 16 are preferably arranged orthogonal to the back 10, 11 introduced.

In the holes 16 are heat pipes 17, and heat pipes 17, preferably arranged positively inserted.

The depth of the bores 16 from the rear sides 10, 11 ago, for example, chosen so that the distance to the forming surfaces 5, 6 is always the same, so that the field of holes 16 and the holes themselves follow the contour as a whole. However, the bores 16 can also be designed, in particular in the region of radii in the contour inclined to the rear sides 10, 11.

In the holes 16, as already stated, each arranged a heat pipe 17 as possible form fit, wherein the heat pipes, as in Fig. 1 shown are different lengths to compensate for the different hole depths of the holes 16 such that the heat pipes 17 on the back sides 10, 11 survive substantially the same length.

But it is also possible to use the heat pipes 17 formed in the same length, through the different depths holes 16, the heat pipes then protrude differently far beyond the backs 10, 11 (corresponding to the contour of the molding surfaces 5, 6).

Of course, these different arrangements can also coexist, whereby in this case the bore density and heatpipe density can additionally be varied.

The tool base body 12, 13 may be formed as solid metal components or be formed as a hollow body, whereby ever a cavity 19 within the tool body 12, 13 is formed. The cavity 19 may in this case for example have connections and be traversed by a cooling medium or contain a non-flowing cooling medium.

Escaping from the bores 16 13 13 holes 20 are arranged in the surfaces 14, 15 of the tool body 12, which are penetrated by the over the surfaces 10, 11 projecting heat pipes or heat pipes 17. The heat pipes or heat pipes 17 are preferably not positively mounted in these bores 20 but with play, wherein the heat pipes 17 in the execution of the tool base body 12, 13 with hollow bodies 19 preferably project into the hollow body 19.

In a further advantageous embodiment, the tool base body 12, 13 are provided without surface 14, 15, so that the tool base body 12, 13 are formed as open, self-supporting patch boxes.

In a further advantageous embodiment ( Fig. 2 ), the heat pipes 17 individually or in groups in the bores 16, 20 slidably be arranged such that the distance to the contour of the surfaces 5, 6 is variable. As a result, the cooling capacity of the cooling jaws can be influenced in particular zonally in such a way that in certain zones the heat dissipation is lower and thus possibly a lower one Curing is achieved when in these areas greater ductility of the components are needed.

Here, the heat pipes 17 and heat pipes 17 can be moved manually disassembled form or in the tool body a corresponding displacement mimic 21 be present.

With such a facial expressions can be reacted very flexibly to requirements, in particular, the heat pipes 17 can be different deep pushed or moved from hub to hub and even within a hub.

In a further advantageous embodiment ( Fig. 3 ), the number, depth or width of the holes and thus also the number, depth of engagement and width of the heat pipes 17 is varied to achieve different or identical cooling conditions.

In order to prevent the heat pipes 17 and the bores 16 against access, in particular, of cooling medium into the cooling jaws 3, 4, seals 18, for example of Teflon or other thermally stable plastics, or rubber seals are arranged around the heat pipes 17, in particular at the mouth of the holes 16. these seals 18 can be arranged only in the region of the bore mouth of the bore 16 in the cooling jaws but also at all other mouths of the bores 16, 20.

In the invention, it is advantageous that an apparatus for producing hardened steel components is provided, which in a simple but very effective manner is capable of a cooling speed which is above the critical hardening speed to ensure, with the cooling capacity is easily adjusted zonally.

LIST OF REFERENCE NUMBERS

1

upper mold half

2

lower mold half

3

upper cooling jaws

4

lower cooling jaws

5

Mold surface of the upper cooling jaw 3rd

6

Shaping surface of the lower cooling jaw 4th

7

sheet metal component

8th

outer surface

9

inside

10

flat back

11

flat back

12

Tool body

13

Tool body

14

flat connection surface

15

flat connection surface

16

drilling

17

Heat pipes or heatpipes

18

poetry

19

cavity

20

drilling

21

shifting facial expressions

Claims (11)

Device for producing hardened steel components, wherein the device comprises at least one tool half (1, 2) and the tool half (1, 2) has a cooling jaw (3, 4) which has an outer mold surface (5, 6) whose contour is the contour a sheet metal component (7) to be hardened substantially corresponds and the cooling jaw (3, 4) has a rear side (10, 11) which serves to connect the cooling jaw (3, 4) to a tool base body (12, 13), wherein Rear side (10, 11) ago a plurality of cylindrical bores (16) are arranged introduced and the bores (16) following the contour of the mold surface with optionally different depths in the cooling jaws (3, 4) extend into, wherein in the holes ( 16) heat pipes (17) are arranged. Device according to claim 1, characterized in that the heat pipes (17) extend beyond the rear side (10, 11). Apparatus according to claim 1 or 2, characterized in that the heat pipes (17) protrude over the rear side (10, 11) substantially at the same height. Apparatus according to claim 1 or 2, characterized in that the heat pipes (17) protrude differently far beyond the rear side (10, 11). Device according to one of the preceding claims, characterized in that the heat pipes (17) are of equal length. Device according to one of the preceding claims, characterized in that the heat pipes (17) have different lengths. Device according to one of the preceding claims, characterized in that adjusting means (21) are provided, wherein the adjusting means (21) acting on the heat pipes (17) are formed and the adjusting means (21) individual heat pipes (17) or groups of heat pipes (17 ) are arranged out of the holes (16) pulled out or hineinbewegend arranged. Device according to one of the preceding claims, characterized in that in the region of the bore opening in the rear side (10, 11) of the cooling jaw (3, 4) a seal (18) is arranged, which with inserted heat conduction tube (17) the bore (16). seals to the outside. Device according to one of the preceding claims, characterized in that on the rear side (10, 11) of the cooling jaw (3, 4), in particular in the tool base body (12, 13) adjacent a water tank (19) or other cooling liquid leading hollow body (19) is arranged, wherein the heat pipes (17) in the water tank or the hollow body (19) extend into it. Apparatus according to claim 9, characterized in that the water box (19) or tool base body (12, 13) in adjacent to the cooling jaw (3, 4) surfaces (14, 15) bores (20), of the heat pipes (17 ) are penetrated in such a way that the heat pipes (17) in the water tank or the hollow body (19) extend into it. Device according to one of the preceding claims, characterized in that two tool halves (1, 2) each having at least one cooling jaws (3, 4) are provided, wherein the contours of the molding surfaces (5, 6) are formed correspondingly such that a between the Form surfaces (5, 6) arranged sheet metal component is held over the entire surface in the closed state of the tool.

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