EP0955107B1 - Mehod of deforming a circular shaped tube in a U-shaped profile and apparatus for executing this method - Google Patents

Description

From exit pipes with a circular cross section through one U-shaped profiles produced without cutting e.g. Wishbones manufactured for car rear axles.

In the forming process carried out so far, a Output tube placed on the edges of an open die, which corresponds to the outer contour of the U-shaped profile Has inner contour. Here is the opening dimension at the mouth of the die is generally smaller than that Output pipe diameter. With a strip-like Patrix, which has a convexly curved tip then from the side opposite the die Output tube pressed in. The patrix has an outer one Contour that corresponds to the inner contour of the profile.

In view of the fact that the opening dimension of the Is generally smaller than the diameter of the die In the known case, the outlet pipe must be formed in the generally about a third of the pipe diameter over the Edges of the die. This creates immediately before the end position of the patrix a situation for the so-called ear covers in such a way that due to resulting moments of resistance on the ear covers the material below on the inside is stretched. This stretch comes in particular in that by moving the male part together and die the material in the on both sides available gap between male and female due to high friction on the walls of patrix and Matrix in the sliding and rolling movement is hindered. This stretching is always transverse to the rolling direction of the Metal from which an output pipe was made, so that compared the mechanical-technological parameters to those clearly limited in the longitudinal direction are. This depends on the mechanical parameters the maximum plastic transverse expansion in the limit range of actually occurring elongation values.

In the case of surface roughness, particularly in the case of hot-rolled insert sheets manufactured output tubes are relatively large, can therefore in the upper limit Roughness values result in a critical cracking situation.

The invention is based on the prior art The task is based on a method for forming an initial tube with a circular cross-section in a U-shaped Profile and a device for performing the method to provide, according to which a significant Reduction of the transverse stress on the material achieved is and thus the production is made more economical can be.

As for the solution of the basic procedural When part of the task arrives, it is described in the characteristics of claim 1 sees.

After that, the front end is made using shaped mandrels positioned output pipe with a circumferential half supported on an abutment at least in some areas. Support is understood to mean at least in some areas, in which the support of the output pipe opposite longitudinal edges avoided and that Output tube in a bowl-like receptacle is placed. Then the strip-like patrix driven against the exit pipe and then this from the the abutment opposite side by means of Male pressed into a U shape. This press-in process takes place until the circumferential half loaded by the patrix of the output pipe over its inner surface with the inner surface of the circumferential half supported on the abutment came into contact.

In this step, the output pipe is through the patrix is initially pressed somewhat oval. In the further Moving the patrix drops the exit tube under the Male until in the end position of the male in particular linear contact of the inner surfaces takes place. Due to the special embedding of the outlet pipe in the abutment the envelopes next to the patrix are relative large loops. This will make one excessive narrow deformation of the pipe material avoided, the the main cross-loading of the material is severe is reduced.

It is important in this deformation step that the starting pipe as such, what remains with it Assured by the mandrels positioned in the front ends becomes. Here the outlet pipe also keeps its original cross section at.

In the second forming step, the male and one are then Die with one of the outer contour of the U-shaped to be produced Profile corresponding inner contour relative to each other relocated. This shift of male and female until the inner surface of the Half of the circumference loaded on the inner surface of the male the circumferential half supporting itself in the inner contour of the die form-fitting to the system. Only that both ear covers still form loops in the smallest size.

It is important in this context that the shaping of the Envelopes are made without friction, as this is no contact with the tools. Your rolling generation runs undisturbed.

If necessary, it is possible according to claim 2 that the U-shaped profile is subjected to calibration. This can vary depending on the contour and functionality of the fabricated Profile. This is another one Significant reduction in the transverse stress on the material connected.

An advantageous embodiment of the invention The method consists in the features of claim 3 the outlet pipe is dimensioned smaller than 180 ° Half of the circumference on a circular trough one-piece abutment supported. This is with associated with the advantage that the ear covers can initially train with relatively large loops.

The patrix is then moved against the exit tube and pressed this in a U shape until the contact of the inner surfaces.

Then the abutment with the trough replaced by a die with a U-shaped inner contour, which corresponds to the outer contour of the U-profile. Then the patrix and the matrix are shifted relative to each other, until that, with the exception of the ear flaps, the inner surface the circumferential half loaded by the male part on the inner surface the circumferential half lying in the die comes to the system in a form-fitting manner.

Another advantageous embodiment of the invention Method is in the features of claim 4 sees. Then a three-part matrix is used as an abutment used at the same time in the second forming step defines the outer contour of the profile.

In the first forming step, the starting pipe is over three Areas of a circumferential half offset by approximately 90 ° to one another supported on the die and the one opposite the die Half of the circumference through the patrix U-shaped indented until the inner surfaces are in line contact to step. Now all parts of the die and the The patrix is displaced relative to each other and the U-shaped one Profile created.

In the second deformation step, the tube wall of the mold jaws pressed against the side of the male part, with only a minimal relative movement between the side mold jaws and the indented outlet tube occurs. The loop-shaped ear covers are subject to a smooth rolling process because the roll radii can be set generously. With regard on the fact that the ear flaps on the profile none There is no contact with the tools Friction. The rolling takes place undisturbed.

Because the rolling from the first contact of the patrix with the starting tube up to the deforming use of the side Mold baking runs unhindered, none occurs until then Wall weakening on. At the time of using the mold jaws the contour of the profile is finished in such a way that a vertical pull on the internal transitions does not occur to the ear covers. With the relative shift The rolling radius then becomes the male and female continuously reduced in size, but reaches its narrow final contour only after the inner surfaces fit together lie.

According to the features of claim 5, all can required or desired embossments in the end position the patrix using a cushion or other Tool techniques are introduced into the profile.

The objective solution of the basis of the invention Task becomes according to a first embodiment seen in the features of claim 6. After that are a strip-like male with a convex curvature On the one hand, an abutment with a circular section Trough and on the other hand a die with a U-shaped inner contour and an arcuate diverging shape Mouth sections interchangeable and relatively relocatable assigned opposite.

That does not cover the entire diameter of the output pipe extending trough allows that in the first Forming step, the outlet pipe assume an ovality and the side ear covers with generous Can form loops slowly. Then the Patrons moved back and the abutment by a Matrix with a U-shaped inner contour and an arcuate diverging shape Mouth sections replaced. Then if the U-shaped pressed-in output tube placed in the die and then relocated the male or female or both parts are moved against each other, slides the preformed profile in the U-shaped inner contour of the Matrix until the end, except for the ear envelopes Inner surface of the circumferential half loaded by the male on the inner surface of the circumferential half lying in the die fits snugly. Dug deepening in the The matrix or the patrix ensure that with their Shaping the ear envelopes not subject to constraints become.

In claim 7 is a variant of an inventive Device described. After that is a strip-like Male with a convexly curved tip also function of an abutment, three-part matrix assigned relatively displaceable opposite. The die is made up of one facing the patrix Support jaw and in itself the patrix supporting counter bearing supporting side mold jaws together. The shaped jaws have the lateral outer contours of the later profile while the support jaw the arcuate area between the legs of the profile shaped. The patrix also has trough-like depressions for the side envelopes.

According to claim 8, the support jaw is preferably roof-shaped designed and her top is arched Provide trough. The contour of the trough corresponds to the curvature of the arcuate section of the profile.

It is expedient according to claim 9 if the lateral Mold jaws with roof-shaped inclined surfaces Support jaw and on diverging inner surfaces of the counter bearing supporting inclined surfaces are provided. hereby the usually two-stage forming process becomes safe guaranteed. If necessary, the entire forming process even in a single forming step be pulled through.

The invention is based on in the drawings illustrated embodiments explained in more detail.

Figur 1

im vertikalen schematischen Querschnitt eine Vorrichtung zur Umformung eines kreisrunden Ausgangsrohrs zu einem U-förmigen Profil vor der Umformung;

Figur 2

die Vorrichtung der Figur 1 am Ende eines ersten Umformschritts;

Figur 3

die Vorrichtung der Figur 1 während der Umformung und nach einem zweiten Umformschritt;

Figur 4

im vertikalen schematischen Querschnitt eine weitere Ausführungsform einer Vorrichtung zur Umformung eines kreisrunden Ausgangsrohrs zu einem U-förmigen Profil vor der Umformung und

Figur 5

die Vorrichtung der Figur 4 nach der Umformung.

Show it:

Figure 1

in the vertical schematic cross section a device for forming a circular exit tube into a U-shaped profile before the forming;

Figure 2

the device of Figure 1 at the end of a first forming step;

Figure 3

the device of Figure 1 during the forming and after a second forming step;

Figure 4

in the vertical schematic cross section a further embodiment of a device for forming a circular starting tube into a U-shaped profile before the forming and

Figure 5

the device of Figure 4 after the forming.

1 in FIG. 1 denotes an output pipe made of steel, which has a circular cross section and deformed into a U-shaped profile 2 according to FIG. 3 shall be.

For this purpose, the output pipe 1 is first used according to FIG a circumferential half 3 in a circular trough one-piece abutment 4 placed. The trough 7 is dimensioned smaller than 180 °. The pipe axis 5 is thereby at a distance above the mouth edges 6 of the trough 7. The distance between the mouth edges 6 is less than the diameter of the outlet pipe 1.

At the end, the outlet pipe 1 is shown in FIG Way by positioned in the foreheads Shaped mandrels held in the position shown in Figure 1.

Above the abutment 4 is a strip-shaped Male 8 with a convex curved tip 9. Die The contour of the patrix 8 corresponds to the inner contour of the one to be produced Profile 2.

By moving the male 8 in the direction of the abutment 4 is the one facing the male 8 according to FIG Circumferential half 10 of the output tube 1 pressed in a U-shape, until that the inner surface 11 of this circumferential half 10 the inner surface 12 of the lying in the trough 7 Circumferential half 3 contacted in a line. Form here itself without constraint above the abutment 4 and laterally the male 8 loop-shaped ear covers 13.

Then the male 8 is again away from the abutment 4 relocated and the abutment 4 by one from FIG Recognizable die 14 with a desired outer contour the profile 2 adapted U-shaped inner contour 15 replaced. Then the outlet pipe pressed in according to FIG. 2 16 at the arcuate diverging mouth sections 17 of the inner contour 15 of the die 14 is placed. Then male 8 and female 14 are mutually relatively shifted. Then the U-shaped Profile 2 generated. Because this profile 2 side loop-shaped Ear envelopes 13 have both the inner contour 15 of the die 14 and the surface 18 the patrix 8 trough-shaped adapted to the ear covers 13 Wells 19, 20 on.

In Figures 4 and 5 is a device for forming an outlet tube 1 which is circular in cross section Steel shown to a U-shaped profile 2, which has a three-part die 21, which also has an abutment function perceives.

The die 21 is composed of a central support jaw 22 and two side mold jaws 23 together. The Support jaw 22 is roof-shaped with the same slope Inclined surfaces 24 and an arcuate trough 25 in the crest 26. Are supported on the inclined surfaces 24 Inclined surfaces 27 of the mold jaws 23, which on the other hand with sloping outer surfaces 28 on diverging inner surfaces 29 one also a strip-like male 8 support supporting thrust bearing 30. The inside 31 of the mold jaws 23 are on the outer contour of the legs 32 adapted to the U-shaped profile. The trough 25 in the Support jaw 23 is on the contour of the arcuate portion 33 of profile 2 adjusted.

To produce the profile 2 according to FIG. 5 first die 21 and counter bearing 30 with male 8 from each other shifted away and the circular exit pipe 1 in the position shown in FIG. 4 into the die 21 embedded. The output pipe 1 is supported here the longitudinal edges 34 delimiting the trough 25 on the dome 26 of the support jaw 22 and in two trough-shaped depressions 35 from the inside 31 of the mold jaws 23.

Then the counter bearing 30 is relative to the die 21 relocated, the male 8 analogous to the illustration 2 the circumferential half adjacent to the male part 8 10 of the output tube 1 presses in a U-shape until the inner surface 11 of this circumferential half 10 on the Inner surface 12 of the ones supported in the die 21 Circumferential half 3 lines up.

By subsequent further relative displacement of the male part 8 and die 21, the mold jaws 23 also being the same shift relative to the support jaw 22 and the counter bearing 30, then the cross-sectional contour of the profile 2 according to Figure 5 generated. It can be seen here that the loop-shaped ear covers 13 in the depressions 35 the mold jaws 23 and in recesses 20 on the male 8 inlay.

The device according to FIGS. 4 and 5 is also used the position of the output tube 1 in the position shown in FIG 4 by retracted into the front ends of the output tube 1 Shaped mandrels not shown during the Pre-deformation guaranteed.

REFERENCE NUMBERS

1 -

outlet pipe

2 -

U-shaped profile

3 -

Circumference v. 1

4 -

abutment

5 -

pipe axis

6 -

Muzzle edges v. 7

7 -

Trough in 4th

8th -

punch

9 -

Kuppe v. 8th

10 -

Circumference v. 1

11 -

Inner surface v. 10

12 -

Inner surface v. 3

13 -

ear portions

14 -

die

15 -

Inner contour of 14

16 -

indented outlet pipe

17 -

Muzzle sections v. 15

18 -

Surface v. 8th

19 -

Deepening on 15

20 -

Deepening on 8

21 -

die

22 -

Support jaw v. 21

23 -

Formbacke v. 21

24 -

Inclined surfaces v. 22

25 -

Trough in 26

26 -

Kuppe v. 22

27 -

Inclined surfaces v. 23

28 -

Outsides v. 23

29 -

Inner surfaces v. 30

30 -

thrust bearing

31 -

Inside of v. 23

32 -

Thigh v. 2

33 -

Bow of 2

34 -

Longitudinal edges from 25

35 -

Deepening in 31

Claims (9)

1. A method of forming a tube blank (1) of circular cross-section into a U-shaped profile (2), wherein the inner surface (11) of a peripheral half (10) of the tube blank (1) bears positively, except for lateral loop-shaped lobes (13), against the inner surface (12) of the oppositely situated peripheral half (3), wherein the tube blank (1) positioned at the end faces by locating pins is first supported, at least in zones, by a perhipheral half (3) against an abutment (4, 21) and is pressed in the form of a U by a punch (8) in the form of a ledge situated frontally opposite the abutment (4, 21) and having a convexly curved crest (9) until contact between the peripheral half (10) of the tube blank (1) loaded by the punch (8) and the diametrically oppositely situated peripheral half (3), whereupon the punch (8) and a die (14, 21) having the outer contour of the profile (2) are moved relatively to one another until completion of the U-shaped profile (2), the locating pins which remain in the end faces being shifted accordingly.
2. A method according to claim 1, characterised in that the U-shaped profile (2) is subjected to a calibration.
3. A method according to claim 1 or 2, characterised in that the tube blank (1) is supported against a one-piece abutment (4) troughed in the form of a portion of a circle and the oppositely situated peripheral half (10) is pressed into the form of a U by the punch (8), the abutment (4) then being replaced by a die (14) of U-shaped inside contour (15) and the tube blank (16) pressed into the form of a U being finally formed into the U-shaped profile by the punch (8) and the die (14).
4. A method according to claim 1 or 2, characterised in that the tube blank (1) is supported against a three-part die (21) as an abutment over three zones of a peripheral half (3) offset by approximately 90° from one another and the oppositely situated peripheral half (10) is pressed into a form of a U by the punch (8), whereupon the three parts (22, 23) of the die (21) and the punch (8) are moved relatively to one another and the tube blank (16) pressed into the form of a U is finally formed into the U-shaped profile (2).
5. A method according to any one of claims 1 - 4, characterised in that embossings are formed in the profile (2) in the end position of the punch (8) by means of die cushions or other tool techniques.
6. Apparatus for performing the method according to any one of claims 1 - 3, characterised in that there are interchangeably associated with a punch (8) in the form of a ledge having a convexly curved crest (9), on the one hand, an abutment (4) having a trough (7) in the form of a portion of a circle and, on the other hand, a die (14) having a U-shaped inside contour (15) and arcuately diverging orifice portions (17), the said elements being disposed opposite one another and displaceable relatively to one another.
7. Apparatus for performing the method according to any one of claims 1, 2 or 4 characterised in that a three-part die (21) which also carries out the function of an abutment is associated with a punch (8) in a form of a ledge having a convexly curved crest (9), the said elements being disposed opposite one another and displaceable relatively to one another, the die (21) consisting of a support jaw (22) situated frontally opposite the punch (8) and of two lateral forming jaws (23) which bear on the one hand against the support jaw (2) and on the other hand against a co-acting bearing (30) carrying the punch (8).
8. Apparatus according to claim 7, characterised in that the support jaw (2) is roof-shaped and its crest (26) is provided with an arcuate trough (25).
9. Apparatus according to claim 7 or 8, characterised in that the lateral forming jaws (23) are provided with inclined surfaces (27, 28) bearing against roof-shaped inclined surfaces (24) of the support jaw (22) and against diverging inside surfaces (29) of the co-acting bearing (30).

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