DE102017211358A1 - Forming process, as well as a corresponding mold and nominal contour - Google Patents

Abstract

In order to create a forming method for producing a desired contour (200) with a high throughput, it is proposed that the desired contour (100) be finished by means of a plurality of horizontal slides (10), so that the still inclined and / or still curved side wall (3) is aligned parallel to the vertical axis H). In order to further provide a forming tool (100) for producing a desired contour (200) with a high throughput, it is proposed that the projection (4) be held between the hold-down surface (13) and the form slides (10) and set up the mold slides (10) are to glide over the supernatant (4). In addition, a corresponding cylindrical nominal contour (200) is proposed.

Description

The invention relates to a forming method according to the preamble of claim 1 for generating a desired contour with a high pull-through height. Furthermore, the invention relates to a molding tool according to the preamble of claim 6 for generating a desired contour with high Durchzughöhe and a cylindrical nominal contour, wherein the cylindrical nominal contour has a vertical axis and a maximum cylinder diameter and the ratio of vertical axis to cylinder diameter is greater than 0.37.

Technical area

The invention relates to a new forming process, which is in the broadest sense associated with thermoforming. In classical deep drawing a sheet metal blank, often referred to as a sheet metal blank, called on a drawing ring, also called die, and a (embossing) stamp dips into the drawing ring and thus generates the desired shape or in the remaining gap between the drawing ring and the punch target contour. The sheet metal blank is held by means of a supernatant on the outer circumference of the target ring by means of a hold-down. This prevents the formation of wrinkles.

A disadvantage of this very simple method is that the Durchzughöhe is limited because the deformation by radial tensile stresses (based on the initially flat sheet metal blank and the supernatant) is obtained. The material thins out, and cracks can occur if the threading height is too high. With traditional deep drawing, ratios of a height to the diameter of a maximum of approximately 2/10 can therefore be generated free of cracks in the case of a cylindrical nominal contour, for example 11 mm in height with a diameter of 56 mm.

This is remedied in this case a mold with a negative drawing gap, so for example with a drawing ring, in which the wall opens conically with respect to the vertical wall of the corresponding punch toward the punch. However, this brings disadvantages in the accessibility of exact nominal contours with desired, for example, consistent, wall thickness with it. In addition, the ratio of height to diameter is only increased to a maximum of 3/10.

State of the art

From the DE 100 20 176 A1 is a method for producing a disc with a thickened hub by deep drawing known. Therein it is shown how by multiple forming steps a cylindrical component with a relation to the sheet blank increased wall thickness can be generated. Something similar will happen in the DE 103 44 885 B3 which deals with a method of manufacturing a hubged workpiece by means of a press and a sheet metal workpiece. In the respective 1 of the two cited scriptures are first seven steps ( DE 100 20 176 A1 , Reference numerals 7a to 7g) and first five steps ( DE 103 44 885 B3 7a to 7e) before the forming steps for increasing the wall thickness are initiated. These are not explained in detail. These writings are relative to each one 1 Therefore, it can be seen that to achieve a desired diameter up to six forming steps, so up to six tools, are necessary to achieve the desired ratio of vertical axis to diameter.

Object of the invention

The invention is based on the object, in a forming process of the type mentioned, the number of steps and tools, which are necessary for generating a desired contour with high Durchzughöhe. According to a further aspect, through-heights are to be achieved, which were previously not achievable by deep drawing.

Solution of the task

This object is achieved by the features specified in claim 1, namely by the target contour is finished by means of a plurality of horizontal stroke exporting mold slides, so that a still inclined and / or still curved side wall is aligned parallel to the vertical axis.

• - eine Niederhalterfläche zum Auflegen einer an die Sollkontur angenäherte Volumenkontur mit einem horizontalen Überstand eines Blechzuschnitts;
• - eine Mehrzahl, bevorzugt vier, Formschieber zum Ausführen eines horizontalen Hubs, wobei der Überstand zwischen der Niederhalterfläche und den Formschiebern gehalten ist und die Formschieber eingerichtet sind, über den Überstand zu gleiten.

Furthermore, the object is achieved by the features specified in claim 6, namely by providing a mold with at least the following components:

• - A hold-down surface for placing a volume contour approximated to the nominal contour with a horizontal projection of a sheet metal blank;
• a plurality, preferably four, pushers for performing a horizontal stroke, the supernatant being held between the hold-down surface and the pushers, and the pushers being adapted to slide over the supernatant.

Furthermore, the object is achieved with a desired contour of the type mentioned, which is produced by means of said forming process, and preferably by means of said molding tool.

Advantageous embodiments of the invention are characterized in the subclaims.

As a result of the measures, it is possible to carry out a forming process in only three steps, that is to say with three forming tools, in a cost-effective manner and with a very high throughfeed height such that the cracking probability is 0%.

Presentation of the invention

1. A. Vorformen einer Volumenkontur aus einem Blechzuschnitt,
2. B. umformende Annäherung an die Sollkontur mit einer Hochachse, wobei eine vertikal auszuformende Seitenwandung der Sollkontur gegenüber der Hochachse noch geneigt ist und ein horizontaler Überstand des Blechzuschnitts vorhanden ist.

According to a first embodiment of the invention, a forming method is proposed for producing a desired contour with a high throughput, which comprises at least the following steps:

1. A. preforming a volume contour from a sheet metal blank,
2. B. reshaping approach to the desired contour with a vertical axis, wherein a vertically auszuformende side wall of the target contour relative to the vertical axis is still inclined and a horizontal projection of the sheet metal blank is present.

The forming process is characterized by a subsequent step C, in which the desired contour is finished by means of a plurality of horizontal slides exporting mold slides, so that the still inclined and / or still curved side wall is aligned parallel to the vertical axis.

In steps A and B of the forming method proposed here, a volume contour is first preformed in two passes, that is to say by means of only two tools, for example a hood shape, as is known from US Pat DE 100 20 176 A1 is known (see 1 , Form 7a). In the second train, so step B., the desired target contour is approximated, with a vertically auszuformende side wall, in a cylinder shape, for example, the cylinder wall is left inclined. The more the side wall is inclined after step B., the more material is available for the final draft height. In conventional thermoforming this potential can not be exploited, however, because here the forming forces alone vertical, ie parallel to the vertical axis, can be introduced.

Here it is now proposed to use a plurality of form slides, which perform a horizontal stroke, ie a stroke transverse to the vertical axis of the later target contour. Completely pushed together, the mold slides form the shape that corresponds to the drawing ring in classic deep drawing. In the center of the desired contour is preferably a stamp die, which corresponds to the stamp in the classic deep drawing. However, in this case the mold slides are moved relative to the desired contour, and the preferred provided stamp die remains immobile relative to the desired contour. The sheet metal blank fills the gap formed between the mold slide and the die stamp, so that an exact wrinkle-free deformation is achieved. Due to the initially inclined present side wall is more sheet metal blank with consequent greater potential for passage. By means of the horizontally moving mold slides, this potential is fully exploitable as a result of the horizontally initiated forming forces.

According to an advantageous embodiment of the forming process, the nominal contour with the vertical axis ( H ) and a maximum cylinder diameter ( D ) cylindrically shaped and it is a ratio ( H / D ) of vertical axis ( H ) to cylinder diameter ( D ) greater than 0.37 achievable. With conventional multi-stage pulling, a maximum value of 0.32 is achievable.

For example, a target contour having a cylindrical shape with a vertical axis ( H ) of 22 mm and one cylinder diameter ( D ) of only 56 mm. According to current knowledge, even a ratio ( H / D ) of 0.39 achievable. Thus, this process exceeds the conventional deep drawing process.

According to an advantageous embodiment of the forming process four mold slides are provided, which are guided diametrically towards each other.

In this preferred embodiment, four mold slides are pushed towards each other in the manner of a jaw chuck, so that they come laterally into contact with each other at the maximum of the horizontal stroke. It was surprisingly found that no wrinkles or beads are formed in the initially present gaps between the mold slides.

According to an advantageous embodiment of the forming method, the target contour has an open bottom surrounded by the side wall with a horizontal edge inclined and / or curved to the center, and in step C. C. a bottom punch executes a vertical lift on the section forming the horizontal edge put on forming open soil.

In this particular embodiment of the forming process, the desired contour has an open bottom, thus forming no closed pot. However, it nevertheless has a horizontal bottom portion which extends from the side wall extends radially to the center of the desired contour. This radially aligned to the center flange is referred to here as (horizontal) edge. The bottom punch described here has a task which corresponds to a mixed form of a hold-down and a stamping die. Preferably, the diameter of the bottom punch is smaller than the diameter of the target contour and the radius between the edge and side wall is formed by the form slides. Preferably, the entire radius of the form slides is shown and the bottom punch is limited to the central, for example, plan, area.

In a preferred embodiment, the bottom punch comes into contact with the portion still inclined to the horizontal before the mold slide comes into contact with the side wall.

If the bottom punch already brought into contact with the section to be reshaped to the edge before the mold slides are applied from the radially outside to the still inclined and / or still curved side wall, a deflection of the sheet metal blank toward the center is reduced or prevented. As a result, more sheet metal blank is available for the Durchzughhöhe to be achieved.

In a particularly preferred embodiment, the bottom punch completes its vertical stroke only after completion of the horizontal stroke of the mold slide.

The bottom punch is only after completion of the horizontal stroke by means of the mold slide completely lowered to the portion which is to form the edge. The edge thus reaches the final shape of the desired contour only after the side wall has reached its final shape. As a result, more material is available from this section for the maximum throughput to be achieved and thus more potential for pulling through.

According to an advantageous embodiment of the forming process, the mold slides are on the horizontal projection on the horizontal projection of the sheet metal blanks on friction.

In this advantageous embodiment, in addition to the potential of the still inclined and / or still curved side wall, additional potential is added from the horizontal projection of the sheet metal blank. While in the conventional deep drawing the material of the supernatant can be supplied only by tensile stresses from the area of the blank holder, the forming method proposed here can be set up such that additional shear stresses or neutral stresses or at least reduced tensile stresses in the material of the supernatant, if due to the friction thrust a portion of the supernatant is supplied to the vertical portion of the target contour by means of the mold slide. As a result, the horizontal expansion potential of the sheet metal blank is utilized to a very high degree.

• - eine Niederhalterfläche zum Auflegen einer an die Sollkontur angenäherte Volumenkontur mit einem horizontalen Überstand von Blechzuschnitt;
• - eine Mehrzahl, bevorzugt vier, Formschieber zum Ausführen eines horizontalen Hubs, wobei der Überstand zwischen der Niederhalterfläche und den Formschiebern gehalten ist und die Formschieber eingerichtet sind, über den Überstand zu gleiten.

According to a further aspect of the invention, a molding tool is proposed for producing a desired contour with a high throughput, wherein the molding tool has at least the following components:

• - A hold-down surface for laying a approximate to the desired contour volume contour with a horizontal projection of sheet metal blank;
• a plurality, preferably four, pushers for performing a horizontal stroke, the supernatant being held between the hold-down surface and the pushers, and the pushers being adapted to slide over the supernatant.

By means of the molding tool, the step C. of the forming process described above is feasible. Thus, the volume contour approximated to the nominal contour of step B. is placed on the hold-down surface.

The hold-down surface corresponds in function to one half of a conventional hold-down, which is adapted to pinch the supernatant. Here, however, this function is exercised by the hold-down surface and the corresponding surfaces of the mold slides. The hold-down surface remains stationary relative to the supernatant, as far as it is not partially stretched in the forming process or completely rubbed by the form slides. Preferably, the hold-down surface is part of a rigid and stationary component of the mold.

The mold slides form in the fully collapsed state, together with their towards the (later) vertical portion of the sheet metal blank aligned molding surfaces of the mold half, which corresponds to the drawing ring in a conventional deep drawing process. Also, in the fully collapsed state, the surfaces corresponding to the holddown surface mentioned in the previous paragraph form the corresponding counterface of the holddown in a conventional deep drawing process. Preferably, these surfaces are completely imaged by the mold slides and without additional surfaces. In contrast to a drawing ring and the counter surface of the blank holder, the mold slides are moved horizontally and slide over the supernatant of the sheet metal blank. In a preferred embodiment, three, four or more mold slides are provided, which are moved along the respective horizontal stroke diametrically toward each other. The mold surfaces of the mold slides preferably correspond exactly to the desired nominal contour. So you have no tendency for a negative drawing gap.

According to an advantageous embodiment of the molding tool, the molding tool further comprises a stamping die, preferably as an integral part of the hold-down surface.

In this preferred embodiment, the stamping die forms a mating surface corresponding to the molding surfaces of the mold slides. The shape corresponds to the die of a conventional deep-drawing process. In contrast to an embossing die, however, the stamping die remains unmoved relative to the sheet metal blank, as far as it is not partially stretched or taken along by the sliding dies. Preferably, the stamp die is part of a rigid and stationary component of the mold, particularly preferably an integral part of the component, which forms the hold-down surface. Preferably, no negative drawing gap is provided between the punch die and the forming surfaces of the mold slides, ie the counterform surface of the stamp die corresponds, for example parallel, to the forming surface of the mold slide.

According to an advantageous embodiment of the mold, the mold further or alternatively comprises a bottom punch, wherein the bottom punch is movable vertically towards the hold-down surface.

In this preferred embodiment, the mold slides do not form the entire surface of a conventional drawing ring. Rather, at least a portion of the bottom is formed by a bottom punch which is movable along a vertical stroke on the sheet metal blank. Preferably, the bottom punch is designed corresponding to a punch die according to the preceding description.

According to a further aspect of the invention, a cylindrical target contour produced by means of a forming method according to an embodiment is proposed as described above, wherein the cylindrical target contour is a vertical axis (FIG. H ) and a maximum cylinder diameter ( D ) and the ratio ( H / D ) of vertical axis ( H ) to cylinder diameter ( D ) is greater than 0.37.

The generated cylindrical desired contour is preferably a rotationally symmetrical cylinder, but may also have an oval or polygonal base surface. Preferably, the height of the side wall, ie in the case of the rotationally symmetrical cylinder of the cylinder wall, is the same over the entire circumference, but may also be of different heights. The cylindrical target contour has a closed or open bottom, and the bottom is flat, ie parallel to the horizontal or has a free form, for example, one or more vaults.

Preferably, said target contour is generated by means of a molding tool according to an embodiment according to the above description.

list of figures

• 1 in einer schematischen Ansicht den Anfangszustand eines Formwerkzeugs mit eingespannter Volumenkontur,
• 2 in einer schematischen Ansicht einen Zwischenzustand des Formwerkzeugs,
• 3 in einer schematischen Ansicht einen Endzustand des Formwerkzeugs, bei welchem die Sollkontur vorliegt,
• 4 eine perspektivische Ansicht eines schematisch dargestellten Formwerkzeugs, und
• 5 eine Sollkontur mit Überstand.

Embodiments of the invention are explained below with reference to the drawing. Show it

• 1 in a schematic view of the initial state of a mold with clamped volume contour,
• 2 in a schematic view an intermediate state of the mold,
• 3 in a schematic view of a final state of the mold, in which the desired contour is present,
• 4 a perspective view of a schematically illustrated mold, and
• 5 a nominal contour with overhang.

Best way to carry out the invention

In 1 is purely schematically a mold 100 shown, in which a volume contour 1 is clamped, which has been generated by (preferably a maximum of two) previous forming steps. The volume contour 1 is about her from the sheet metal blank 2 formed supernatant 4 between the pushers 10 and the hold-down surface 13 clamped. Central in the volume contour 1 there is a stamping die 12 , From in the illustration above is a bottom stamp 11 along the vertical stroke axis ( z ) lowered. The volume contour 1 has a still inclined and still curved side wall 3 on. This volume contour 1 has an open floor 5 on. At the open ground 5 is a still inclined and still curved portion 7 is provided, which later to a horizontal edge 6 (see 3 ) is transformed. The mold slides 10 are now along the radial or horizontal Hubachsen ( r ) towards each other or towards the stamp die 12 method. The slides slide 10 over the supernatant 4 of the sheet metal blank 2 ,

2 shows the mold 100 in an intermediate state, in which the sheet metal blank 2 an intermediate contour 8th which has already reached the final contour to about 75% headstamp 11 is not yet in contact with the section 7 and the section 7 is therefore still inclined and curved.

In 3 the final state is shown, in which the volume contour 1 (see 1 and 2 ) in the shape of the desired contour 200 has been spent. Both the mold slide 10 as well as the bottom stamp 11 are maximum, that is complete, along the horizontal stroke axis ( r ) or the vertical lifting axis ( z ). In a suitable process control, the remaining gap is completely removed from the sheet metal blank 2 filled, which in this area the target contour 200 formed. Here is now also by means of the Bodenstempels 11 the horizontal edge 6 from section 7 (cf. 1 and 2 ) educated.

In 4 is a perspective view of a schematically illustrated mold 100 shown which four shape slider 10 which in each case along the radially aligned to the center horizontal Hubachse ( r ) are mutually displaceable. In the center is a volume contour 1 arranged. The volume contour 1 is from a sheet metal blank 2 preformed and has an open bottom 5 and a supernatant 4 on. By means of the supernatant 4 is the volume contour 1 between the hold-down surface 13 and the pushers 10 clamped.

In 5 is an example of a desired contour 200 which is cylindrical and has a vertical axis ( H ) and a cylinder diameter ( D ) having. In addition, the target contour 200 an open ground 5 and a horizontal border 6 on. The side wall 3 is vertical, ie parallel to the vertical axis ( H ). The nominal contour 200 is here with a supernatant 4 shown. For some applications, this supernatant 4 separated for example by punching. In one main application, this supernatant forms material for subsequent forming steps or other shaping steps. The relationship ( H / D ) between the length of the vertical axis ( H ) and the length of the diameter ( D ) is about 0.375 in this example.

LIST OF REFERENCE NUMBERS

100

mold

200

target contour

1

volume contour

2

sheet metal blank

3

sidewall

4

Got over

5

open ground

6

edge

7

section

8th

between contour

10

shape shifter

11

headstamp

12

Stempelmatrize

13

Down surface

r

horizontal stroke axis

z

vertical stroke axis

H

vertical axis

D

Cylinder diameter

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10020176 A1 [0005, 0014]
• DE 10344885 B3 [0005]

Claims (9)

Forming method for producing a desired contour (200) with high throughput, comprising at least the following steps: A. preforming a volume contour (1) from a sheet metal blank (2), B. reshaping approach to the desired contour (100) with a vertical axis (H), wherein a vertically auszuformende side wall (3) of the desired contour (200) relative to the vertical axis (H) is still inclined and a horizontal projection (4) of the sheet metal blank (2) is present, characterized in that in a step C. the desired contour (100 ) is finished by means of a plurality of a horizontal stroke (r) exporting form pushers (10), so that the still inclined and / or still curved side wall (3) is aligned parallel to the vertical axis (H). Forming process after Claim 1 , wherein the target contour (200) with the vertical axis (H) and a maximum cylinder diameter (D) is cylindrically shaped and a ratio (H / D) of the vertical axis (H) to cylinder diameter (D) greater than 0.37 is achievable. Forming process after Claim 1 or 2 , wherein four mold slides (10) are provided, which are guided diametrically towards each other. Forming method according to one of the preceding claims, wherein the desired contour (200) has an open bottom (5) surrounded by the side wall (3) with a horizontal edge (6) inclined and / or curved towards the center, and a bottom punch (C) in step C. ( 11) a vertical stroke (z) executing on the horizontal edge (6) forming portion (7) of the open bottom (5) to be formed is placed, wherein preferably the bottom punch (11) with the inclined to the horizontal section ( 7) comes into contact before the mold slide (10) comes into contact with the side wall (3), and most preferably only after the horizontal stroke (r) of the mold slide (10) ends the vertical stroke (z). Forming method according to one of the preceding claims, wherein the mold slides (10) during the horizontal stroke (r) on the horizontal projection (4) of the sheet metal blank friction lie. Molding tool (100) for generating a desired contour (200) with high throughput, comprising at least the following components: - A hold-down surface (13) for placing a to the target contour (200) approximate volume contour (1) with a horizontal projection (4) of a sheet metal blank (2); - A plurality, preferably four, mold slide (10) for carrying out a horizontal stroke (r), wherein the supernatant (4) between the hold-down surface (13) and the form slides (10) is held and the mold slides (10) are arranged over to slide the supernatant (4). Forming tool (100) after Claim 6 wherein the molding tool (100) further comprises a punch die (12), preferably as an integral part of the hold-down surface (13). Forming tool (100) after Claim 6 or 7 wherein the forming tool (100) further comprises a bottom punch (11), wherein the bottom punch (11) is movable vertically towards the hold-down surface (13). Cylindrical target contour (100) produced by means of a forming process according to one of Claims 1 to 5 , preferably by means of a molding tool according to one of Claims 6 to 8th , wherein the cylindrical target contour (100) has a vertical axis (H) and a maximum cylinder diameter (D) and the ratio (H / D) of the vertical axis (H) to cylinder diameter (D) is greater than 0.37.

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