EP2484462B1 - Method for producing a forge preform and warm upsetting device - Google Patents

Description

The invention relates to a method for producing a forging preform for forging a forged part, in which a contour of a workpiece is formed into a forging contour using a forming tool, wherein the forging contour corresponds to a first forged part contour with a required volume predistribution of the forging to be forged.

Furthermore, the invention relates to a forming device or a hot forging device for producing a forging preform for forging a forged part with a forming tool, wherein the forming tool has a workpiece forming contour with variable cross sections, by means of which a volume predistribution of the forging preform can be generated.

It is known to produce forging of forged parts before a first forging step from a substantially cylindrical workpiece a forging preform with variable cross-sections, which is then provided in the form of a semi-finished product for a first forging stage. In this case, the production of a preform serves, in particular, to already achieve volume accumulations, so that the subsequent forging stages can be carried out more simply and in particular with minimal material loss.

The forming of the substantially cylindrical workpiece to the forging preform is done in the prior art by means of transverse and / or stretching rolling process, in which a forging preform with an already defined volume pre-distribution is worked on the substantially cylindrical workpiece. This makes it much easier to get started in the actual forging process.

However, corresponding rolling tools for the known transverse and / or Reckwazverfahren are not only costly to manufacture, but also offer special with regard to a required volume distribution at the forging preform only small Nachstell- or correction options.

On the other hand it is from the DE 199 16 590 A1 known to provide Schmiedevorformen by upsetting, for this purpose, a upsetting is carried out in a cavity in which a cavity is formed by matrices, in which an upsetting die dips to appropriately transform the workpiece into the cavity, so that its surface then essentially the Surface of the Werkstückumforminnenkontur the cavity corresponds.

When upsetting, however, a distinction must be made between a compression in a cavity, as this in the DE 199 16 590 A1 is disclosed, and a free compression, like this in the DE 1 301 297 B1 is disclosed and in which no cavity is provided and a workpiece is clamped on both sides of a deformation region by means of clamping jaws, which are then moved toward each other in compression, wherein the material builds up during upsetting in the space between the two jaws.

While free upsetting naturally only allows a few possibilities of intervention to produce mass differences across the semifinished product cross section in the compressed area, this is precisely what the DE 199 16 590 A1 a device and a method for generating large differences in mass across the semi-finished product, but this still leads to considerable rejects for complex products to be forged, so that must continue to resort to conventional transverse and / or stretching roll.

Generic methods and devices are for example from the EP 0 786 296 A1 or from the JP 59-054440 A known.

It is an object of the present invention, in particular, to overcome the abovementioned disadvantages when producing a forging preform by means of conventional transverse and / or stretching rolling methods.

The object is achieved by a method according to claim 1 or by a forming device according to claim 6.

Further advantageous embodiments are defined in the dependent claims.

Further advantages, objects and features of the present invention will be explained with reference to the appended drawing and the following description, in which on the one hand by way of example a hot-swaging device which according to the invention has a forging preform tool and on the other hand a forming device for forming a workpiece are shown and described.

Figur 1

schematisch eine erste Ansicht einer Warmstauchvorrichtung mit einem geöffneten Umformwerkzeug zum Erzeugen einer Schmiedevorformkontur an einem Werkstück;

Figur 2

schematisch eine weitere Ansicht des geöffneten Umformwerkzeugs aus der Figur 1 mit eingelegtem Werkstück vor einer Stauchphase;

Figur 3

schematisch eine Ansicht des Umformwerkzeugs aus den Figuren 1 und 2 in geschlossenem Zustand während einer Stauchphase;

Figur 4

schematisch nochmals eine Ansicht des wiedergeöffneten Umformwerkzeugs aus den Figuren 1 bis 3 mit einer fertig gestauchten Schmiedevorform nach der Stauchphase;

Figur 5

schematisch eine Querschnittsansicht durch ein vorderes Längssegment der Warmstauchvorrichtung aus den Figuren 1 bis 4 bei geöffnetem Umformwerkzeug;

Figur 6

schematisch eine Querschnittsansicht durch das vordere Laingssegment der Warmstauchvorrichtung aus den Figuren 1 bis 5 bei geschlossenem Umformwerkzeug;

Figur 7

schematisch eine Ansicht einer vorderen, mittleren und hinteren Festmatrize des Umformwerkzeugs;

Figur 8

schematisch eine Ansicht der Festmatrizen des Umformwerkzeugs nach Figur 7 in zusammengeschobenem Zustand mit vier zugehörigen Querschnitten; und

Figur 9

schematisch eine Ansicht weiterer vorderer, mittlerer und hinterer Festmatrizen eines Umformwerkzeugs in zusammengeschobenem Zustand mit vier zugehörigen Querschnitten in ähnlicher Darstellung wie Figur 8.

In the drawing show:

FIG. 1

schematically a first view of a hot-swaging device with an open forming tool for producing a Schmiedevorformkontur on a workpiece;

FIG. 2

schematically another view of the open forming tool from the FIG. 1 with inserted workpiece before a compression phase;

FIG. 3

schematically a view of the forming tool from the Figures 1 and 2 in the closed state during an upsetting phase;

FIG. 4

schematically again a view of the reopened forming tool from the FIGS. 1 to 3 with a finished blacksmith preform after the compression phase;

FIG. 5

schematically a cross-sectional view through a front longitudinal segment of the heat-upsetting of the FIGS. 1 to 4 with open forming tool;

FIG. 6

schematically a cross-sectional view through the front Laingssegment of the hot-swaging device from the FIGS. 1 to 5 with closed forming tool;

FIG. 7

schematically a view of a front, middle and rear fixed die of the forming tool;

FIG. 8

schematically a view of the fixed dies of the forming tool after FIG. 7 in collapsed condition with four associated cross sections; and

FIG. 9

schematically a view of further front, middle and rear fixed dies of a forming tool in the collapsed state with four corresponding cross sections in a similar representation as FIG. 8 ,

The in the FIGS. 1 to 4 Forming device 1 shown comprises a forming tool 2, which in the illustration according to the FIG. 1 is shown open.

The forming device 1 in this embodiment is a hot-swaging device 3.

With regard to an upsetting axis 4 of an upsetting die 5 of the forming device 1, the forming tool 2 is radially configured in two parts in an upper part 6 and in a lower part 7.

The upsetting punch 5 is guided through a punch guide 5A and it can be moved by a drive not shown here in alignment with the upsetting axis 4 in the forming tool 2 or out of the forming tool 2 out.

The forming tool 2 has a cavity 8 with variable cross sections 9, which accordingly provides an asymmetrical workpiece forming inner contour 10 within the forming tool 2.

The forming tool 2 is additionally divided in this embodiment into three longitudinal segments 11, 12 and 13, wherein the front longitudinal segment 11, a front Festmatrize 14 and a front clamping die 15, the middle longitudinal segment 12, a middle Festmatrize 16 and a central clamping die 17 and the rear longitudinal segment 13 comprises a rear fixed die 18 and a rear clamping die 19.

In this respect, the cavity 8 is designed both radially and axially in several parts.

Each of the clamping matrices 15, 17 and 19, respectively, is fixed but hinged to its associated fixed die 14, 16 and 18, respectively, by means of a corresponding hinge connection 20. It is understood that in other embodiments, other arrangements of the different matrices and deviating measures to a positioning of the same can be provided to each other.

The forming device 2 of this embodiment is also characterized by a common Axialführungseinrichtung 21, to which all Festmatrizen 14, 16 and 18 via the respective hinge joint 20 - and thus indirectly also all clamping matrices 15, 17 and 19 - are mounted axially displaceable one behind the other.

The Axialführungseinrichtung 21 is in this embodiment structurally simple designed as a single linear crossmember. But it can also be implemented as a multi-part component or group of components, should this be necessary.

In order that the individual longitudinal segments 11, 12 and 13 on the common Axialführungseinrichtung 21 also can be quickly replaced, the forming device 1 still has a holding device 22 with holding elements 23, 24 and 25th

By means of the holding elements 23, 24 and 25, the longitudinal segments 11, 12 and 13 are fixed in a displaceable manner on the common axial guide device 21.

The individual fixed matrices 14, 16 and 18 are screwed in the present embodiment by means of screw 26 to the respective holding elements 23, 24 and 15. It is understood that other connection options, such as quick release or positive connection, can be provided here.

Since in particular two axially adjacent fixed dies 14, 16, 18 of the forming tool 2 are arranged axially loosely adjacent to one another, the forming device 1 has an axial stop 27, on which especially the fixed dies 14, 16, 18 can be axially supported during an upsetting process.

The axial stop 27 is designed in this embodiment structurally simple as a replaceable component of the axial guide 21.

To create a forging preform 30 (see FIG. 4 ) with a Schmiedevorformkontur 31 with variable cross-sections 32 for the subsequent forging of a forgings, not shown here, a workpiece 33 with a substantially cylindrical contour 34 is inserted into the cavity 8 (see FIG. 2 ).

Subsequently, the forming tool 2 is closed, as it is in the FIG. 3 is shown. The respectively on the fixed matrices 14, 16 and 18 lowered clamping matrices 15, 17 and 19 are respectively locked by means of a quick clamping device 35, 36 and 37 respectively. In this respect, a popping of the forming device 2 is excluded during the compression process.

Now the actual compression phase according to a compression movement 38 (see FIG. 3 ) take place, in which the arrangement around the upsetting die 5 and the punch guide 5A on the one hand pushes the individual longitudinal segments 11, 12 and 13 against the axial stop 27 and on the other hand simultaneously upsetting punch 5, the workpiece 33 within the cavity 8 compresses, the workpiece 33 to the forging preform 30 is deformed with the variable cross sections 32.

Advantageously, the forging preform 30 now has a defined volume distribution which substantially corresponds to that of a forging part after a first forging step.

In this respect, according to the invention, a hot upsetting method for producing a forging preform 30 with variable cross sections 32 for producing a forged part is used for the first time.

The sectional view according to the FIG. 5 shows the forming device 1 in the region of the front longitudinal segment 11 with the forming tool 2 open.

The front fixed die 14 of the forming tool 2 is fastened with two first screws 40 and 41 of the screw connection 26 to the first holding element 23 of the holding device 22.

After the sectional illustration shown, it can be seen well that the first holding element 23 has an upper part 42 facing the front solid die 14 and a lower part 43 facing the axial guiding device 21.

The upper part 42 is in this case screwed with two hexagon socket screws 44 and 45 to the lower part 43, it being understood that in this regard in other embodiments, other types of fastening or a one-piece design of Solid die 14 may be provided. The remaining fixed matrices 16, 18 are similar in this embodiment, but this need not necessarily be the case.

The axial guide device 21 comprises a foot part 46 and a guide part 47, on which the longitudinal segments 11, 12 and 13 of the forming tool 2 are displaceably mounted.

The guide member 47 is screwed along the Axialführungseinrichtung 21 with a number of other screws 48 to the foot part 46.

At the upper part 42 of the first holding member 23, the first quick-clamp connection 35 of the hinge joint 20 is flanged with a Flanschverschraubung 49.

The quick-clamping connection 35 has a lever mechanism 50, by means of which the front longitudinal segment 11 of the forming tool 2 can be manually opened or closed.

While the quick-clamp connection 35 corresponds to the upper part 42 by means of a lower leg 51, the quick-clamp connection 35 is screwed to a corresponding upper leg 52 on the front clamping template 15. For this purpose, a screw 53 is provided.

It is understood that instead of a manual operation and a motor, especially a hydraulic or pneumatic drive can be provided.

The sectional view according to the FIG. 6 shows the forming device 1 in a closed state, in which the front clamping die 15 is lowered onto the front Festmatrize 14. Here, the cavity 8 is closed at least in the region of the front longitudinal segment 11.

The quick clamping mechanism 35 is here in a locked position 54, so that the front clamping die 15 does not lift off from the front fixed die 14 during a forming process and thereby the forming tool 2 would be at least partially opened.

The features of the first longitudinal segment 11 explained here can be transferred to the further longitudinal segments 12 and 13 so that they are not additionally explained

Each in a schematic plan according to the FIGS. 7 and 8th For example, the front solid die 14, the middle solid die 16, and the rear solid die 18 are again exemplified. The Festmatrizen 14, 16 and 18 are arranged along the upsetting axis 4 axially behind one another and in particular during the upsetting axially of the arrangement according to FIG. 7 to the arrangement FIG. 8 moved together. Although this procedure is not mandatory and it is conceivable that the matrices are already collapsed before upsetting or even in the axial direction only one die is used, but this to relatively large axial movements between the workpiece and tool just in the inner wall of the Workpiece, which on the one hand increase wear and on the other hand energy consumption.

The front fixed die 14 configures a first lower subspace 55 of the cavity 8 of the forming tool 2. Accordingly, the middle fixed die 16 form a second lower subspace 56 and the rear fixed die 18 form a third lower subspace 57 of the cavity 8. In addition, corresponding upper subspaces (not shown) of the clamping matrices 15, 17 and 19. It is easy to understand that thereby the cavity 8 with respect to the Werkstückumforminnenkontur 10 can be varied overall complex and versatile and in particular a variety of variable cross sections 9 of the cavity 8 to be represented can, as in FIG. 8 are exemplified, which can then lead to correspondingly variable cross-sections 32 of the forging preform 30.

The subspaces 55, 56 and 57 of the fixed matrices 14, 16, 18 and the corresponding subspaces of the clamping matrices 15, 17, 19 are procedurally relatively simple in this embodiment by means of an erosion process in the respective die 14, 15, 16, 17, 18 and 19 incorporated.

As a result of this and due to the large number of individual subspaces 55, 56 and 57 etc., substantially more complex forging contour contours 31 can be produced than is possible with conventional rolling methods with regard to the production of a forging preform 30.

The front Festmatrize 14 has two countersunk bores 58 and 59 for the two previously described screws 40 and 41.

Corresponding counterbores (not numbered separately here) can be found on the two fixed matrices 16 and 18.

Since the first subspace 55 has a subspace diameter 60 that is critically greater than an associated subspace length 61 of the first subspace 55, means 62 for partially reducing the subspace diameter 60 are provided in the subspace 55, which are implemented as a flank dome 63 in this embodiment.

In the present case, the flank mandrel 63 comprises a clamping mandrel-side fixed longitudinal mandrel 64 and a fixed-die-side fixed longitudinal mandrel 65 (see FIG Figures 5 and 8th ), which protrude into the cavity 8.

In this respect, a means for indexing a desired flow behavior is arranged within the cavity 8; in areas of the cavity 8, in which the subspace diameter 60 is greater than a designated inner diameter 66 of the forming tool 2, in which the upsetting die 5 is arranged or guided.

Thus, even during the closing of the forming tool 2, at least in regions, radial pressure jaws can be exerted on the workpiece 33 in a structurally particularly simple manner, which in particular run essentially perpendicular to the axial upsetting direction 38.

In this respect, the workpiece 33 is thereby at least partially reshaped, so that the corresponding workpiece material flows within the subspace 55 before the actual Axialstauchprozess with a desired flow behavior, whereby a breaking of the workpiece 33 during the axial upsetting is almost impossible.

In the FIG. 9 illustrated embodiment substantially corresponds to the embodiment according to FIGS. 1 to 8 , so that identically acting assemblies are also numbered identically. In deviation from the embodiment according to FIGS. 1 to 8 the embodiment according to FIG. 9 Means 62 for partially reducing the subspace diameter 60, which protrude much less into the cavity 8 and the workpiece 33 when closing the matrices 14 to 19 substantially only frictionally in the radial direction, ie parallel to the subspace diameter 60, fix. Depending on the specific process control, an elastic deformation by means of corresponding molding areas 67, 68 of the means 62 for partially reducing the partial space diameter 60 is sufficient for this purpose, in which case a plastic deformation may also be provided. Already by an elastic deformation or by only one frictional engagement, the risk of lateral breakage can be successfully minimized in order to be able to reliably fill also large cross-sections, in particular over the axial extension of the workpiece 33. List of reference numerals: 1 reshaping 30 forging preform 2 forming tool 31 Forging preform contour 3 Warm clincher 32 variable cross sections 4 compression axis 33 workpiece 5 swaging dies 34 cylindrical contour 5A punch guide 35 first quick-clamping device 6 top 36 second quick-clamping device 7 lower part 37 third quick-clamping device 8th cavity 38 upsetting movement 9 variable cross sections 40 first screw 10 Werkstückumforminnenkontur 41 second screw 11 front longitudinal segment 42 upper part 12 middle longitudinal segment 43 lower part 13 rear longitudinal segment 44 first hexagon socket screw 14 front solid die 45 second hexagon socket screw 15 front clamping die 46 footboard 16 medium solid die 47 guide part 17 middle clamping die 48 more screws 18 rear fixed die 49 flange bolting 19 rear clamping die 50 Lever mechanism 20 articulation 51 lower thigh 21 axial guidance 52 upper leg 22 holder 53 Screw 23 first holding element 54 locked position 24 second holding element 55 first lower subspace 25 third retaining element 56 second lower subspace 26 Screw connections 57 third lower subspace 27 axial stop 58 first counterbore 59 second counterbore 60 Subspace diameter 61 Subspace length 62 Means for reducing 63 edge Dorn 64 Längsdom 65 Längsdom 66 designated inner diameter 67 shaping area 68 shaping area

Claims (14)

1. A method for producing a forge preform (30) for forging a forged component, in which, using a forming tool (2), a contour (34) of a workpiece (33) is reshaped to obtain a forge preform contour (31), characterised in that the workpiece (33) is placed into a cavity (8) of the forming tool (2) and during closing of the cavity (8) is shaped at least partially, the workpiece (33) is then upset in the closed forming tool (2) to obtain a forge preform (30) and thereafter can be provided as a forge preform (30) with a defined volume pre-distribution for use in a subsequent forging process.
2. The method according to claim 1, characterised in that the workpiece (33) is plastically shaped.
3. The method according to claim 1, characterised in that the workpiece (33) is merely elastically shaped.
4. The method according to one of claims 1 to 3, characterised in that the workpiece (33) is already held in a friction lock prior to upsetting.
5. The method according to one of claims 1 to 4, characterised in that the forming tool (2) comprises more than one longitudinal segment (11, 12, 13), which are arranged spaced apart from one another at the start of the upsetting process and during upsetting are positioned so as to form a common cavity in relation to one another.
6. A forming device (1) or warm upsetting device (3) for producing a forge preform (30) for forging a forged component by means of a forming tool (2), in which the forming tool (2) comprises a workpiece forming contour (10) with variable cross-sections (9), by means of which a volume pre-distribution can be produced on the forge preform (30), characterised in that the forming tool (2) comprises a designated inner diameter (66) on a side facing a header die (5), wherein the forming tool (2), in subspaces (55) of the cavity (8) with a subspace diameter (60) larger than the designated inner diameter (66), comprises means (62) for partially reducing the subspace diameter (60).
7. The forming device (1) or warm upsetting device (3) according to claim 6, characterised in that the forming tool (2) comprises a cavity (8) with variable cross-sections (9).
8. The forming device (1) or warm upsetting device (3) according to claim 6 or 7, characterised in that the forming tool (2) comprises more than one longitudinal segment (11, 12, 13) and in that the longitudinal segments (11, 12, 13) are arranged axially one behind the other on a common axial guidance unit (21).
9. The forming device (1) or warm upsetting device (3) according to claim 8, characterised in that the longitudinal segments (11, 12, 13) of the forming tool (2) are arranged so as to be exchangeable on the common axial guidance unit (21).
10. The forming device (1) or warm upsetting device (3) according to one of claims 6 to 9, characterised in that the cavity (8) is designed in several parts both radially and axially, in particular is designed so as to be variable.
11. The forming device (1) or warm upsetting device (3) according to one of claims 6 to 10, characterised in that the forming tool (2), in subspaces (55) of the cavity (8) with a subspace diameter (60) larger than the designated inner diameter (66), comprises means (62) for partially reducing the subspace diameter (60) vertically to the larger subspace diameter (60).
12. The forming device (1) or warm upsetting device (3) according to one of claims 6 to 11, characterised in that the forming tool (2), in subspaces (55, 56, 57) with a subspace length (61) greater than 1.5 times the subspace diameter of the respective subspace (55), comprises means (62) for partially reducing the subspace diameter (60).
13. The forming device (1) or warm upsetting device (3) according to claim 11 or 12, characterised in that the means (62) for partially reducing the subspace diameter (60) comprises a flank thorn (63) which partially protrudes into the cavity (8) of the forming tool (2).
14. The forming device (1) or warm upsetting device (3) according to one of claims 11 to 13, characterised in that the means (62) for partially reducing the subspace diameter (60) comprise at least one friction-lock-forming shaping area (67, 68).

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