DE102014112320A1 - Press forming tool with compensation pad - Google Patents

Abstract

The present invention relates to a press forming tool (1) comprising an upper tool (5.1, 5.2, 5.3, 5.4) and a lower tool (4), which are movable towards each other and with closed Pressumformwerkzeug (1) between the upper tool (5.1, 5.2, 5.3, 5.4 ) and lower tool (4) a mold cavity (7) is formed, which is characterized in that between the upper tool (5.1, 5.2, 5.3, 5.4) and a press ram (2) and / or between the lower tool (4) and a press table (3) a hydraulic compensation pad (6) is arranged, wherein the upper tool (5.1, 5.2, 5.3, 5.4) and / or the lower tool (4) via the hydraulic compensation pad (6) are floating.

Description

The present invention relates to a press forming tool according to the features in the preamble of claim 1.

The present invention further relates to a method for operating a press forming tool according to the features in claim 10.

From the state of the art Pressumformwerkzeuge for the production of Blechumformbauteilen are known. For this purpose, a sheet metal blank is inserted into the press forming tool and then transformed by moving an upper tool and a lower tool. For this purpose, an upper tool is usually lowered by means of a press ram, wherein at plant contact of upper tool with board and board with lower tool reshaping of the board begins to upper tool and lower tool are closed so that under integration of the board between the upper tool and lower tool remains a mold cavity. In the mold cavity, the formed blank is then finally formed into the component to be produced by the press forming. In the case of multiple top tools arranged side by side in a press, so that two, three or more blanks are simultaneously formed in parallel with one component, this can lead to a different system contact between the individual tools. The components produced at the same time are therefore subject to minimal production tolerances due to a distortion of the upper tool, lower tool, press table and / or press ram and deviations of the tolerances of the upper tools and the lower tools to each other.

Furthermore, in the prior art, hot working and press hardening for hardenable steel alloys are known. Here, boards made of a hardenable steel alloy are heated to a temperature above AC3, so that they are completely austenitized. These heated blanks are then placed in the press forming tool and formed while warm. After completion of the press forming, with completely closed Pressumformwerkzeug the component is then preferably cooled in the press forming tool so fast that a quench hardening takes place. This process is also known as press hardening. Is now due to the above-mentioned tolerances not direct and direct contact between the surface located in the press forming tool component and inside of the tool surfaces to record, the cooling power is reduced due to minimal air gaps in these areas and it sets a lower cooling rate. This has an effect on the cycle time for the production of the component, with longer retention times must be provided, the more and / or larger air gaps exist.

The object of the present invention is therefore to show a press forming tool in which a compensation possibility of upper tool and / or lower tool is provided so that production tolerances occurring during press forming are reduced, in particular with multiple falling tools.

The aforementioned object is achieved with a press forming tool according to the features in claim 1.

The procedural part of the object is further achieved by a method according to the features in claim 10.

Advantageous embodiments of the present invention are the subject of the dependent claims.

The present invention relates to a press forming tool comprising an upper tool and a lower tool, wherein upper tool and lower tool are movable towards each other. When the press forming tool is closed, a mold cavity remains between the upper tool and the lower tool. The mold cavity corresponds with its inner contour of the outer contour of the component to be produced, so that a deformed board in the mold cavity on the upper tool and also on the lower tool is substantially full surface to the plant. To compensate now production tolerances, in particular to achieve a full contact with the press forming tool closed, the present invention provides that between the upper tool and a press ram and / or between the lower tool and a press table, a hydraulic compensation pad is arranged, wherein the upper tool and / or the lower tool are floatingly mounted via the hydraulic compensation pad.

In the context of the invention, therefore, it is possible in particular to produce a virtually gap-free system contact between the formed sheet metal blank as well as the tool surface of the upper tool and / or lower tool. In the case of press hardening, a particularly good heat transfer is thus recorded, due to the full surface contact contact. According to the invention, there is thus a shortening of the cycle time. The press hardening can be finished faster, because due to the improved heat transfer, a reliable cooling to the target temperature of all areas is produced.

In the context of the invention, there is thus the possibility that, due to the floating bearing, the upper tool is mounted floatingly with respect to the press ram while incorporating the compensating pad and / or the lower tool is mounted floatingly with respect to the press table while incorporating the compensating pad. This makes it possible within the scope of the invention that due to the floating bearing tilting of upper tool to lower tool and thus a non-full-surface concerns of the formed to the component board in the mold cavity is avoided. It is also made possible that in the case of a multiply falling tool, thus arranged side by side upper tools and / or lower tools, the respective corresponding upper tools and lower tools when closing the tool and / or fully closed tool to each other. In the context of the invention is thus to be understood as a floating storage of the lower tool on the press table, so that the lower tool is mounted due to the gravitational force by incorporation of the compensation pad floating on the press table or on a clamping plate arranged on the press table. For the upper tool, the definition applies accordingly, wherein in the open position of the Pressumformwerkzeuges the upper tool first hangs on a clamping plate and between the compensation pad and the upper tool an air gap is formed. Only when the upper tool is pressed by moving the Pressumformwerkzeuges to the compensation pad and turn on the press ram or attached to the press ram clamping plate, then the floating bearing is formed here so that a relative movement between the upper tool and press ram or clamping plate is made possible.

Due to the floating bearing thus in particular a relative movement of the upper tool and / or lower tool of a few tenths of a millimeter to a few millimeters is possible. In addition, the applied pressing force is homogenized when the tool is completely closed. A possible deflection of the press table and / or press ram is compensated by the floating bearing, such that upper tool and lower tool are optimally aligned in their relative position to each other and the applied pressing force is particularly homogeneously introduced to the upper tool and / or the lower tool by the floating storage. The compensation pad is thus located respectively on the back of the upper tool and / or lower tool and is preferably coupled in the case of the upper tool of a clamping plate on the press ram and in the case of the lower tool with a clamping plate arranged on the press table. For this purpose, the press ram has, in particular, a flat press plate which is connected in a slide-rigid manner, the hydraulic compensation pad then being correspondingly coupled to the press plate. Hereinafter, this is abbreviated as press ram.

The hydraulic compensation pad itself is in the context of the invention, in particular formed by a single-layer compensating cushion cover and has a flexible surface or flexible wall. In the context of the invention, the compensation cushion cover can also be designed in several layers. For this purpose, in particular the compensation cushion itself is formed from a thin-walled sheet metal material. In the context of the invention, however, it is also conceivable to form the compensation pad from a rubber-like and / or plastic-like material. In the context of the invention may also be used a fiber-reinforced material, so that this, in particular by the press forming self-applied pressure force withstands.

Further particularly preferably, the compensation pad is then provided on a rear side with one side, which faces the upper tool or the lower tool, with a base plate or sealing plate, in particular, the base plate forms the back of the compensation pad. The base sheet is then preferably attached to a clamping table and in turn is fluid-tightly coupled to the leveling pad, so that a fluid-tight space between the leveling pad and the base sheet is provided in the leveling pad. Preferably, a circumferential frame or a circumferential strip is further provided, which couples the compensation cushion cover and the base plate at a predetermined distance from each other, wherein the distance corresponds in particular in its height to the Aufsetzleisten described below. The compensation pad can then have the same dimensions in width and depth of the press table itself in the case of a press table. However, the compensation pad can also be formed only partially on the press table, in particular in the arrangement of several sub-tools on a press table, so that the compensation pad then preferably has the width and depth of a bottom of the lower tool. Each lower tool can then be attached to the press table with the inclusion of an individual compensation pad. In order to enable a preferred coupling and in particular a simple and quick tool change, a clamping plate is further provided on the press table, on which the compensation pad, in particular the base plate of the compensation pad is attached. For the upper tool above mentioned versions apply analogously.

So that now the upper tool and / or the lower tool are captively connected to the press ram or press table, in particular a positive storage, which allows a relative play to provide. In particular, this is formed by sliding blocks, most preferably by T-shaped nuts on a clamping plate. The T-shape of the sliding block is characterized in particular such that a neck and a transverse to the neck T-shaped web are formed. Over the length of the neck can then take place a relative movement of upper tool to press ram. By the T-shaped web and by a bearing surface of the press ram or the clamping plate this relative movement is delimited. The same applies in reverse order then for the press table.

Likewise, the sliding blocks can be positioned such that a relative movement of the upper tool can be carried out transversely to the press ram and, in the case of the lower tool, transversely to the press table.

In order to avoid metallic beating during opening and closing of the press mold according to the invention, it is particularly preferred that an elastic bearing, in particular an elastic stop or damper, be provided between the upper tool and the sliding block. For this example, a Teflon material or even a rubber-like plastic material can be used. Optionally, it is possible to use the elastic stop also made of a relatively soft metallic material in relation to the tool steels used for the tools and / or press ram and / or press table.

The press forming tool according to the invention can be operated in two different ways. A first method provides that the floating storage is operated passively. This means in the compensation cushion prevails a constant always prevailing hydraulic pressure. The compensation pad is thus filled with a hydraulic medium, in which case the relative movement from upper tool to press ram or from lower tool to press table lead to a displacement of the compensation pad. The prevailing hydraulic pressure within the compensation pad is therefore constant and is only increased by the press force when the press forming tool is completely closed, or distributes it evenly.

An alternative embodiment variant provides that the hydraulic pressure in the compensation cushion is actively controlled. For this purpose, there is particularly preferably a base pressure in the compensation pad. When closing or shortly after completely closed Pressumformwerkzeug then the base pressure can be increased by an operating pressure. Thus, the hydraulic pressure in the compensation pad is increased. The base pressure can also be zero. Thus, when the press forming tool is held closed, the pressure acting on the component is further increased by the operating pressure of the hydraulic medium. Due to the floating storage of upper tool to press ram and / or lower tool to press table this ensures in particular that any gaps and / or spaces between the tool surface and the surface of the formed blank are closed so that a nearly complete contact with the plant is achieved.

A particularly preferred embodiment provides that at the beginning of the forming stroke the pressure prevailing in the compensation pad is equal to zero. The forming force is thus initially transferred exclusively via the press forming tool, wherein the upper tool and lower tool transmit the pressing force on the Aufsetzleisten to the reshaped board. When the press ram is at bottom dead center, the balance pad is filled with a predetermined defined volume of oil hydraulic fluid. The press ram itself holds its holding power, but is easily raised by the hydraulic force applied to the balance pad. For this purpose, for example, a hydraulic pressure between 1 and 2 MPa, preferably between 1.3 and 1.7 MPa used. If, for example, a press table with a width and depth of 3000 × 2000 mm is used, this results in a holding force of the tappet of 1000 tons. For this purpose, for example, an oil pressure of 1.6 MPa with an oil volume for a 2 mm high lifting of the plunger of 12 liters can be introduced into the compensation pad.

For this purpose, a hydraulic cylinder is particularly preferably arranged on the press-forming tool, with which volume and pressure in the fluid to be introduced can be precisely controlled and optionally adapted when the tool is changed. Particularly preferably, an oil is used as the hydraulic medium.

In particular, when carrying out the press forming tool according to the invention as a hot forming and press hardening tool or alternatively only as a press hardening tool, it is thus possible that due to the complete plant contact a homogeneous cooling of the board takes place. This makes it possible in particular to set the microstructural properties of the material targeted and homogeneous.

Another significant advantage in carrying out the press hardening process is that due to the full-surface contact with the system a reduction the quenching time is made possible because the better heat transfer due to the complete contact with the plant is reliable. The cycle time of an inventive equipped Pressumformwerkzeuges can thus be reduced, while ensuring that a complete press hardening has taken place.

In the context of the invention, in particular a plurality of adjacently mounted upper tools and / or lower tools can be arranged on a press ram or on a press table. A respective upper tool and a respective lower tool are then aligned precisely to one another due to the floating bearing.

In the context of the invention, however, it is also possible for an upper tool and / or a lower tool to be segmented into a plurality of parts. This segmented tool design is particularly suitable for the hot forming of large-area components, such as side members, tunnel reinforcement, vehicle pillars and bumpers. The individual segments are then movable relative to each other and relatively movable, mounted on the press ram or the press table.

To transfer the press force is further provided in the invention, that are arranged on the press table and / or the press ram Aufsetzleisten. The Aufsetzleisten provide with completely closed press mold by at least partially formed contact with the respective upper tool or lower tool for a complete transfer of the press force. If the upper tool or lower tool has a corresponding misalignment or misalignment to the press table and / or press ram, the press force is transmitted via the compensation pad and the prevailing hydraulic pressure therein.

Further advantages, features, characteristics and aspects of the present invention are the subject of the following description. Preferred embodiments are shown in the schematic figures. These are for easy understanding of the invention. Show it:

1 a cross-sectional view through an inventive mold,

2 a partial view of an upper tool according to the invention at top dead center

3 a partial view during the closing time,

4 a plan view of a press plate as inventive press ram and

5 a partial section through an inventive compensation cushion. In the figures, the same reference numerals are used for the same or similar components, even if a repeated description is omitted for reasons of simplicity.

1 shows a press forming tool according to the invention 1 comprising a top-mounted press ram 2 and a bottom-mounted press table 3 , On the press table 3 is a lower tool 4 arranged. The lower tool 4 itself has four lower tool parts 4.1 . 4.2 . 4.3 . 4.4 on. At the press ram 2 itself are four upper tools 5.1 . 5.2 . 5.3 . 5.4 hung. The four upper tools 5.1 . 5.2 . 5.3 . 5.4 are on the press ram 2 under inclusion of a hydraulic compensation pad according to the invention 6 stored floating. It thereby becomes every single top tool 5.1 . 5.2 . 5.3 . 5.4 allows a relative movement R both relative to the lower tool 4 as well as opposite the press ram 2 perform, so that in each case an optimal mold cavity 7.1 . 7.2 . 7.3 . 7.4 between upper tool 5.1 . 5.2 . 5.3 . 5.4 and lower tool 4 or the respective tool surfaces 8th . 9 from upper tool 5.1 . 5.2 . 5.3 . 5.4 and lower tool 4 established. A not shown in between integrated board, thus has a nearly complete contact with the tool surfaces 8th . 9 which leads to a shortened cooling time in the case of a cooled press hardening tool. These are indicated both in the upper tool 5.1 . 5.2 . 5.3 . 5.4 as well as in the lower tool 4 trained cooling channels 10 , 2 shows a detailed view of two side by side suspended upper tools 5.1 . 5.2 , The upper tools 5.1 . 5.2 are doing relatively movable on a T-shaped sliding block 11 hung up, leaving the top tool 5.1 . 5.2 on a support surface 12 a T-shaped web, based on the vertical direction V in in 2 shown top dead center, rests. The compensation pillow 6 itself is on a plunger plate 13 of the press ram 2 formed fitting. An elastic means is indicated on a side surface, so that on the one hand a guiding takes place in the transverse direction Q, but on the other hand a metal impact is suspended as it were by the elastic means. It is also conceivable within the scope of the invention between support surface 12 as well as upper tool 5.1 . 5.2 to incorporate an elastic agent. In the indicated arrow can with a hydraulic block clamp the T-stone towards the press ram 2 be tense. Shown in 3 can on the support surface 12 appropriate rubber blocks 22 be positioned so that in an upward movement no metal impact occurs and a corresponding damping is present.

The two side-by-side hung top tools 5.1 . 5.2 are to the lower tool 4 guided with a sliding guide. A lateral movement of an upper tool 5 can be done only in the context of a sliding gap.

3 shows the view in a bottom dead center. It can be seen that, relative to the vertical direction V, the respective upper tool 5.1 . 5.2 with the compensation pad 6 brought into abutting contact and by further lowering the plunger plate 13 or the press ram, not shown 2 according to a force F of the press is transmitted to the circuit board, not shown. Within the scope of the invention, a relative movement R of the upper tool is particularly preferred 5.1 . 5.2 to plunger plate 13 less than 10 mm, in particular less than 5 mm. Opposite the balance cushion 6 is the respective upper tool 5.1 . 5.2 then stored again floating, so that it is completely closed Pressumformwerkzeug 1 can be ideally aligned with respect to the lower tool and the system contact to be manufactured to the formed board. A homogenization of the contact pressure in the closed state is also achieved.

4 shows a plan view of the in 2 and 3 indicated surface 15 the plunger plate 13 a press ram. On the surface 15 of the base sheet 23 is an outside surrounding frame 16 , which is the balancing pillow 6 fluid-tight with the surface 15 of the base sheet 23 coupled. The frame 16 itself has a connection opening or a valve opening in order to provide the in 2 shown in more detail hydraulic medium 19 between surface 15 and compensating cushion cover 18 to insert as well as to connect an active pressure regulator to that between equalization cushion cover 18 and surface 15 applied pressure of the hydraulic medium 19 to actively adjust.

Furthermore shown in 5 the balancing pillow 6 in a cross-sectional view. To recognize here is the compensation cushion according to the invention 6 with his compensation cushion cover 18 and the outside surrounding frame. Furthermore, it is good to see that the height H16 of the frame 16 the height H20 of the Aufsetzleiste corresponds. The frame 16 and the base plate 23 as well as the compensation cushion cover 18 are preferably coupled together by a thermal joining process. For this purpose, all components are formed of a metallic material.

Further illustrated are Aufsetzleisten 20 , wherein a Aufsetzleiste 20 also in 3 is shown indicated. By completely lowering the press ram 2 comes so with the Aufsetzleiste 20 with a back 21 of the respective upper tool 5.1 . 5.2 at least partially in positive contact and thus transmits the force F of the press ram 2 completely on the board to be reshaped. A possible area in which no contact is made, at least a part is preferably also an equal proportion of the applied force F through the press ram 2 due to the pressure of the hydraulic medium 19 transfer.

LIST OF REFERENCE NUMBERS

1

forming die

2

press ram

3

press table

4

lower tool

5

upper tool

6

equalizing pads

7

mold cavity

8th

Tool surface too 5

9

Tool surface too 4

10

 cooling channel

11

 sliding block

12

 bearing surface

13

 ram plate

14

 bearings

15

 surface

16

 frame

17

 valve opening

18

 Compensation cushion cover

19

 hydraulic medium

20

 Aufsetzleiste

21

 back

22

 rubber block

23

 base plate

F

force

H16

Height too 16

H20

Height too 20

Q

 transversely

R

relative movement

V

 vertical direction

Claims (12)

Press forming tool ( 1 ) comprising an upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and a lower tool ( 4 ) which are movable towards each other and with the press-forming tool closed ( 1 ) between upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and lower tool ( 4 ) a mold cavity ( 7 ), characterized in that between the upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and a press ram ( 2 ) and / or between the lower tool ( 4 ) and a press table ( 3 ) a hydraulic compensation pad ( 6 ), wherein the upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and / or the lower tool ( 4 ) via the hydraulic compensation pad ( 6 ) are floating. Press forming tool according to claim 1, characterized in that the compensating cushion ( 6 ) a flexible compensation cushion cover ( 18 ), wherein the compensating cushion cover ( 18 ) out a sheet material or a rubber-like material and / or plastic is formed and / or that as the back of the compensation pad ( 6 ) a base plate ( 23 ) is formed, wherein the base plate ( 23 ) fluid-tight, in particular with the inclusion of a frame ( 16 ) with the compensation cushion cover ( 18 ) is coupled. Press forming tool according to claim 1 or 2, characterized in that in the balancing cushion ( 6 ) a hydraulic medium ( 19 ) is received fluid-tight. Press forming tool according to the preceding claim, characterized in that the hydraulic medium ( 19 ) has a constant pressure or that the pressure of the hydraulic medium ( 19 ) is actively controllable. Press forming tool according to one of the preceding claims, characterized in that the upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and / or the lower tool ( 4 ) on sliding blocks ( 11 ), in particular T-shaped sliding blocks ( 11 ), wherein the nuts ( 11 ) a relative displacement (R) in the press direction to the press ram ( 2 ) or the press table ( 3 ) is possible. Press forming tool according to one of the preceding claims, characterized in that in the contact area of upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and slot nut ( 11 ) and / or lower tool ( 4 ) and slot nut ( 11 ) a plain bearing ( 14 ) and / or a rubber block ( 22 ) is arranged. Press forming tool according to one of the preceding claims, characterized in that the press forming tool ( 1 ) is designed as a hot forming and press hardening tool. Press forming tool according to one of the preceding claims, characterized in that the upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and / or the lower tool ( 4 ) is divided into at least two adjacent segments or that at least two upper tools ( 5.1 . 5.2 . 5.3 . 5.4 ) and / or at least two sub-tools ( 4 ) are arranged side by side, wherein preferably each segment and / or each upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and / or each lower tool ( 4 ) own compensation pad ( 6 ) assigned. Press forming tool according to one of the preceding claims, characterized in that between the upper tool ( 5.1 . 5.2 . 5.3 . 5.4 ) and the press ram and / or between the lower tool ( 4 ) and the press table ( 3 ) Aufsetzleisten ( 20 ) are arranged, wherein the Aufsetzleisten ( 20 ) occurring during forming press force (F) by at least partially positive contact under inclusion of the compensation cushion cover ( 18 ) transmits. Method for operating a press forming tool ( 1 ) according to at least claim 1, characterized in that the press forming tool ( 1 ) is closed and is acted upon at or immediately after closing with an operating pressure. A method according to claim 10, characterized in that when opening the press forming tool ( 1 ) the balancing cushion ( 6 ) is decompressed and thereby or temporally thereafter the press ram is raised. Method according to claim 10 or 11, characterized in that in the compensating cushion ( 6 ) is a base pressure is applied and the base pressure for the Pressumformvorgang particular the pressing process, particularly preferably for a quench hardening process is increased to an operating pressure, in particular, the base pressure is substantially zero.

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