EP1706228B1 - Hot flow forming and bending method, and device for carrying out said method - Google Patents

Abstract

Disclosed is a method for hot flow forming and bending closed, half-open, and open profiled members. Said method uses a bending machine comprising at least two rollers (17, 18) which are disposed across from each other in the feeding direction of the bending profiled member and behind which at least one milling roller (14) and an opposite central roller (11) are arranged at an axial distance in the feeding direction, said at least one milling roller (14) and central roller (11) jointly embodying a roll bending zone for the profiled member that is to be shaped. At least one bending roller (13) which can be moved against and away from the profiled member that is to be bent is arranged at the discharge end. In order to be able to shape thin-walled and sensitive open, half-open, and closed profiled members, at least the rollers (11, 14) located in the roll bending zone are heated.

Description

The invention relates to a method for hot-flow forming and a device for carrying out this method according to the preamble of claims 1 and 11.

From older applications of the same applicant is known to bend with so-called four-roller bending machines and sensitive and thin-walled, closed, semi-open and open profiles.

The bending takes place in the form of two- or even three-dimensional shapes.

When forming profiles z. B. magnesium alloys or even in high-strength steels has been found that a pure cold-forming bending is not sufficient. Due to the high strength of the material to be reshaped and associated brittleness, the formability is not sufficient to reshape the profile satisfactorily. At certain degrees of deformation, the profile breaks, tears or is otherwise damaged, so that it has not previously been possible to bend such delicate profiles.

Especially with thin-walled profiles, it has been found that these profiles tend to bulge and a conversion has not been possible.

According to US-A-3,368,377 the pipe to be bent is heated by an induction heater before the bending operation.

The invention is therefore based on the object to propose a novel method for bending deformation of thin-walled and sensitive, open, semi-open and closed profiles, which works reliable.

To solve the problem, the invention is characterized by a method according to the technical teaching of claim 1.

It is essential that at least the rollers arranged in the bending roll zone are heated.

In a preferred embodiment of the invention, it is provided that the arranged there and opposing roles that create the opposite walls of the profile, are heated accordingly.

Although the term "rolling roll" is used in the following description for at least one of these two roles. However, this is not literal to understand, because these roles functionally no longer exclusively a Auswalzaufgabe, but they also serve the shape of the profile in the bending roll zone. The actual bending of the profile takes place at a distance between the bending roller located at the rear in the inlet direction and at least one support roller arranged at a distance in the inlet direction at the front.

However, the invention is not limited to the heated arrangement of rolling rolls in the region of the bending roll zone. Of course, it is also possible to heat additional rollers, in particular the support roller arranged in the inlet direction in front of the bending-rolling zone, and the opposite counter-roller, which make it possible to support the profile to be bent with respect to the bending roller at the front in the inlet direction.

There are also various embodiments for the formation of the heating, all of which are to be included in the subject matter of the present invention.

In a first preferred embodiment of the invention, it is provided that in the bending roll zone opposite each other arranged rolling rolls (namely, the upper roller and the opposite center roller) are electrically conductive (high-current carrying) are formed. For this purpose, each roller carries an outer current-carrying jacket, which is electrically insulated inwardly by an insulating ring from an inner support, wherein the carrier is rotatably connected in a conventional manner with the shaft.

The opposite role is formed in the same way. If now a relatively high current of z. B. 1000 to 2000 amps to give a role, then there are a number of differently extending current paths that extend at least partially through the profile to be bent. Due to corresponding resistance heating, the profile is heated highly efficiently only in the bending roll zone. These rungs go - as stated - partly through the profile to be bent. However, some of the current paths also run inwards in the direction of a mandrel shaft held in the region of the bending-rolled zone, via the mandrel rod of which part of the current flows is likewise discharged to the outside. As a result, the resistance heating also takes place in the interior of the profile.

Another current flow takes place through the opposing rollers directly under electrical interposition of the conductive profile, so that only the bending roll zone is concentrated and heated with high efficiency at very high temperatures.

In the forming of thin-walled magnesium profiles or magnesium alloy profiles, temperatures in the bending-rolled zone of approximately between 150 and 200 ° C. are generated.

In the conversion of high-strength steel sheet profiles, however, temperatures in the range between 700 and 900 ° C are preferred.

Important in this embodiment is that concentrated only in the bending roll zone, a relatively high heating takes place. This heating is preferably generated by said current flow resistance heating.

However, the invention is not limited thereto. The invention can also provide that the opposed rolling rolls are equipped with known heating cartridges which preheat the rolling rolls.

It is also possible to insert heating coils in the opposite rolling rollers, to heat them also via a corresponding current flow.

In addition to the mentioned resistance current flow heating and heating with individual heating elements is provided in a further development of the invention that the rolling rolls are heated by other heating means such. B. by liquid heating means, which are conducted into the interior of the rolling rolls, by hot air heating means which act directly on the rollers, by infrared or by inductive heating of the rolling rolls.

Likewise, these rolling rolls can be heated by means of laser energy. All mentioned heating methods can also be combined with each other.

The invention is also not limited to the heating of the roller and the roller opposite this with respect to the bending roll zone.

In a further development of the invention, it is provided that perpendicular to the two rollers mentioned, so-called vertical rollers are additionally heated. All heating methods are used, as described above. The said vertical rolling rolls attach themselves to the side wall of the profile to be bent, where they concentrate the heat into the profile to be bent into the side wall.

In particular, when the aforementioned current flow heating is used, there are also current flow paths which extend over the vertical rolling rolls.

The invention is not limited to the heating of rolling rolls in the region of the bending roll zone, but it is provided in a development that the rollers lying in the inlet direction are heated. These are the support roller and the opposing roller opposite the support roller, which in turn both bear against the opposite walls of the profile.

These two roles can be heated by all the above heating mechanisms. The heating in this area then corresponds to a preheating of the profile, which is then finally heated concentrated in the Biegewalzzone and heated. This significantly improves the transformation of sensitive profiles.

The controlled arrangement of current paths, which result from the fact that the opposing rolling rolls in the bending roll zone create an electrically conductive effect on the profile, result in precisely defined current paths, so that it is possible by the application of the current, the temperature in the bending roll zone to be regulated precisely to + - 1 ° C.

To control appropriate temperature sensors are arranged on the opposite rollers, which regulate the flow of current through the arrangement.

In a further development of the invention, it is otherwise provided that further preheating takes place on the inlet side of the profile, namely in the region of the machine bridge. This preheating may consist of a heating channel, in the interior of which a number of several heating stations arranged one behind the other are arranged.

These heating stations can provide a predefined heating of the profile in any way.

However, it is hereby preferred that each heating station is designed as a radiant heater (IR heater). In addition to the radiant heating but also other heating mechanisms can be used, such. B. induction heaters and preferably other non-contact heating methods.

With the given technical teaching, there is the advantage that even very sensitive magnesium and magnesium alloys or aluminum-magnesium alloys can be safely transformed for the first time even with thinnest wall thicknesses, without any breakage or buckling of the profile.

To support the profile from the inside, a mandrel shaft is preferably carried in the interior of the profile, which is fastened to a mandrel rod.

In this case, it is preferred if a link chain is arranged at the front end, which runs supportingly in the interior of the profile and extends out of the bending zone into the region of the bending roller so as to offer the bending roller a corresponding counter bearing.

For a support of the profile relative to the bending roller is achieved, so that the bending roller can not deform the profile later.

Here it is provided in a development of the invention that the mandrel shaft is heated. As already stated above, the heating is preferably carried out via the described Stromflussheizung.

For the heating of the mandrel shaft, however, all other previously mentioned heating mechanisms can be used individually and / or in combination with one another, in particular radiation heating, liquid heating, laser heating and the like.

In the following the invention will be explained in more detail with reference to drawings showing only one embodiment. Here are the drawings and their description further features and advantages of the invention.

Figur 1:

schematisiert dargestellte perspektivische Ansicht einer Warmfließformbiegemaschine nach der Erfindung

Figur 2:

eine vergrößerte teilweise Darstellung des Biegekopfes im Schnitt

Figur 3:

die Darstellung der Warmfließformbiegemaschine nach Figur 1 mit weiteren Einzelheiten

Figur 4:

ein Schnitt gemäß der Linie IV-IV in Figur 3

Figur 5:

ein Schnitt gemäß der Linie V-V in Figur 3

Show it:

FIG. 1:

schematically illustrated perspective view of a hot-forming bending machine according to the invention

FIG. 2:

an enlarged partial view of the bending head in section

FIG. 3:

the representation of the hot-flow forming machine according to Figure 1 with further details

FIG. 4:

a section along the line IV-IV in Figure 3

FIG. 5:

a section along the line VV in Figure 3

In Figure 1, a machine bridge 1 is shown, on which a number of successively arranged guide stations 3, 4, 5 is attached. At the rear side of the machine bridge a mandrel holding station 2 for the support of 2 mandrel bars 6, 7 is arranged.

The guide stations 3, 4, 5 are used both for guiding the mandrel bars 6, 7 and for guiding a profile 21, which is not shown in detail, to be reshaped.

In a manner not shown, this profile 21 is clamped in a gripping head 8, which is connected to a sliding carriage 9.

The slide carriage 9 is driven by drives 10 in the longitudinal direction of the machine bridge 1, so as to insert the profile 21 to be formed into the bending head 70.

From Figures 2 and 3 show more details.

FIG. 3 shows that, in one embodiment, it is essential that a heating channel 30 is assigned to the profile 21 to be formed.

This heating channel consists of a series of successively arranged heating stations 31, 32, 33, each of which heating station has a plurality of radiators 34, 35.

Further, in the heating channel 30 still guide rollers 37 are arranged, which are mounted oscillating and are employed by means of spring elements 38 against the profile 21 to be formed.

The section through the half-channel 30 is shown in FIG. There, the individual, previously mentioned parts are drawn in section.

Instead of 2 mandrel bars 6, 7 - as shown in Figure 1 - only a single mandrel 6 is used here.

With reference to Figures 2 and 3, the novel bending head 70 according to the invention will now be explained in more detail.

It consists essentially of a center roller 11, which is rotatably mounted on a rotation axis 12 and is driven to rotate in the direction of arrow 29, for example.

The center roller 11 is - opposite the bending profile - a rolling roller 14, so that by these two rolling rollers 11, 14 a bending roll zone 40 for the reshaped profile 21, 21 'is defined.

Thus, the rolling roller 14 may be driven and in addition the thrust slide 9 operates in the direction of the longitudinal axis of the profile 21 in order to push it through the bending roll zone 40.

In the interior of the hollow profile in this case a mandrel shaft 25 is arranged in the region of the bending roll zone 40, which preferably consists of several elements.

The rear end of the mandrel shaft 25 is formed by a first support member 26 which is arranged in the intermediate space between a support roller 17 and one which is the opposite counter-roller 18.

In the region of the bending-rolled zone 40, the mandrel shaft 25 forms a second support element 27, which prevents buckling or collapse of the profile in the region of the bending-rolled zone 40.

In the area to the front of the mandrel shaft 25 is connected to a link chain 28, which consists of individual, hingedly interconnected links which rest against the inner wall of the hollow profile, wherein the link chain 28 leads into the region of the bending roller 13.

The bending roller 13 is formed pivotable and can be delivered in any way to the profile to be bent 21 ', so as to achieve a defined bend.

The bending of the profile to be reshaped is thus preferably effected by the action of the bending roller 13 on the profile 21 to be formed, whereby a corresponding back pressure is achieved by the spaced behind the support roller 17.

However, the forming (a hot-flow forming bending) takes place in the region of the bending-rolled zone 40.

FIG. 5 shows that in the region of the bending-rolled zone 40, further rolling rolls can be arranged, which rest against the upper and lower side walls of the profile. The vertical rollers 15, 16 are shown in FIG.

The purpose of these vertical rollers is to additionally guide the profile in the area of the side wall and to prevent it from breaking out in this area.

Incidentally, it is not shown in detail that in the area of the supporting and counter rollers 17, 18, vertical rollers 19, 20 can again be arranged in a vertical plane, as indicated in FIG.

Incidentally, the entire profile 21 rests on a support table 22 in order to prevent the profile from sinking.

The bending head has, moreover, a bottom 23 and an upper lid 24.

Now important is the electric current heating in the region of the bending roll zone 40, as shown in more detail with reference to FIG 2.

First, it can be seen that the upper roller 14 is rotatably mounted on a sliding carriage 65, which is formed in the direction of the profile to be bent and wegstellbar.
At this slide carriage 25, the one pole of a current flow source is now applied, while the other pole of the current flow source is electrically conductively connected to the opposite center roller 11.

It therefore comes to the formation of the current paths 55-64, which are entered in the drawing with the current paths A1 to A10 in detail.

For example, the current path A1 extends from the central roller 11 via the electrically conductive jacket 41 on the surface of the profile 21 and is redirected there in the form of the current path 62 (A8) and flows over the profile.

The current path A3 merges into the current path A4. The current path A5 goes into the current path A6. The current path A7 merges into the current path A8. The current path A9 goes into the current path A10.

All current paths are networked together and electrically connected with each other.

The introduction of a relatively large current which flows via the electrically conductive jacket 41 of the rolling roller 14 onto the electrically conductive profile 21 and from this profile onto the electrically conductive jacket 41 of the center roller 11 results in concentrated high-energy heating zones in the region of the bending roll zone 40 , so that the sensitive profile is concentrated heated only in the area of this forming zone.

It is also shown that the same heating mechanisms with the current paths can also be arranged in the region of the vertical rolling rollers 15, 16 arranged perpendicular thereto.

It is also shown that the mandrel shaft 25 is formed electrically conductive, wherein the support members 26, 27 are also electrically conductive and the current is then finally discharged via the mandrel 6 to the rear.

The figure 2 shows, moreover, that the support roller 17 and the counter-roller 18 are electrically heated in the same manner, wherein a corresponding current flow is introduced via the thrust slide 66 and the opposite pole, for example, electrically connected to the mantle of the counter-roller 18.

This results in the current paths 45-54 with the designations B1 to B10 entered in the drawing.

Again, there is a manifold branching of the current paths, this Stromflussbeheizung is to be regarded in the field of support roller 17 and the counter-roller 18 as preheating for the actual heating in the bending roll zone 40.

Again, it may be provided that perpendicular thereto vertical rolling rollers 19, 20 are arranged, which may be heated in the same manner.

Incidentally, the bending roller 13 is also mounted on a sliding carriage 67, but the bending roller 13 is not heated.

As already mentioned above, each heated by current flow heating roller 11, 14, 17, 18, 15, 16, 19, 20 of an electrically conductive jacket 41, which is isolated via an electrically insulating insulating ring 43 of an optionally conductive support 42. The respective carrier 42 is then rotatably connected respectively to the shaft 44.

3, it is also noted that the outlet-side end of the heating channel 30 is provided with a closure plate 39 in order to prevent impermissible escape of the heat developed therefrom from the heating channel 30.

The entire heater is associated with a correspondingly sized transformer, which provides the corresponding power outputs available.

The essential difference of the hot-flow forming process according to the invention for cold-flow bending is that during cold-flow forming, the bending rolls require a certain penetration depth into the material of the profile to be formed, in order to achieve a microstructure flow. This structure flow is achieved by a rolling effect and this by a specific Penetration depth of the profile cross section reached in the reshaped profile. Here is a significant difference to the novel hot-flow bending according to the invention, because - as previously shown - the actual rolling rollers, namely the center roller 11 and the roller 14 make no actual Auswalzung the profile more, but only assume a support function and a power line.

Due to the resistance heating in the rolling bending zone 40, a heating in the structure of the profile to be formed is generated in order to make the structure bendable. A corresponding magnesium profile would not be deformable at room temperatures. Here, the aforementioned twisted heating in the bending roll zone is made possible to make the structure of the magnesium alloy flowable and a union in the region between the bending roller 13 and the spaced therefrom support roller 17 made union.

Based on a high-strength steel material, this means that this high-strength steel material in the bending roll zone in the temperature range between 700 to 1000 ° C must be heated to also allow a microstructure flow in the bending roll zone and thereby achieve the first time the transformation of this profile.

drawing Legend

1

machines bridge

2

Dorn holding station

3

transfer station

4

transfer station

5

transfer station

6

mandrel

7

mandrel

8th

chuck

9

Traverse frame

10

drive

11

Central role

12

axis of rotation

13

Bending roller 13 '13 "

14

roller

15

Vertical roller

16

Vertical roller

17

supporting role

18

counter-roller

19

Vertical roller

20

Vertical roller

21

Profile 21 '

22

support table

23

Bottom (bending head)

24

cover

25

spike shaft

26

Support element (rear)

27

Support element (front)

28

link chain

29

arrow

30

heating duct

31

heating station

32

heating station

33

heating station

34

Spotlight (above)

35

Spotlight (side)

36

Guide (slide carriage 9)

37

leadership

38

spring element

39

End plate

40

Roll-bending zone

41

coat

42

carrier

43

insulation

44

wave

45

Rung B1

46

Rung B2

47

Rung B3

48

Rung B4

49

Rung B5

50

Rung B6

51

Rung B7

52

Rung B8

53

Rung B9

54

Rung B10

55

Rung A1

56

Current path A2

57

Rung path A3

58

Rung path A4

59

Rung A5

60

Rung A6

61

Rung A7

62

Rung A8

63

Rung A9

64

Rung A10

65

Traverse frame

66

Traverse frame

67

Traverse frame

68

69

70

bending head

Claims (17)

1. Process for the hot flow-form bending of thin-walled closed, half-open or open profiled sections with a bending machine comprising a bending head consisting of at least two rolls (17, 18) which are arranged opposite one another in the feed direction of the profiled section (21, 21') to be bent, and at an axial distance behind which in the feed direction at least one milling roll (14) and one opposing middle roll (11) are arranged which together constitute a roll-bending zone (40) for the profiled section (21, 21') to be worked, at least one bending roll (13) that can be traversed towards and away from the profiled section to be bent being arranged on the discharge side, characterized in that at least the rolls (11, 14) arranged in the roll-bending zone (40) are heated.
2. Process according to Claim 1, characterized in that other rolls of the bending machine are heated too.
3. Process according to Claim 1 or Claim 2, characterized in that the support roll (17) arranged before the roll-bending zone in the feed direction and the opposing counter-roll (18), which enable the profiled section to be supported against the bending roll forward-located in the feed direction, are heated.
4. Process according to Claim [sic] according to any one of Claims 1 to 3, characterized in that the milling rolls arranged opposite one another in the roll-bending zone are electrically conducting and are energized by a high current which passes through the profiled section (21, 21') to be worked, at least in the region of the roll-bending zone.
5. Process according to any one of Claims 1 to 4, characterized in that in the roll-bending zone, the applied current is also conducted to the inside of the profiled section to be worked, on a mandrel shank arranged in the interior.
6. Process according to any one of Claims 1 to 5, characterized in that the rolls are heated by a liquid heating medium.
7. Process according to any one of Claims 1 to 6, characterized in that the rolls are heated up by electrically heated cartridge heaters and/or heater coils.
8. Process according to any one of Claims 1 to 7, characterized in that the rolls are heated up by radiation heating and/or by induction heating.
9. Process according to any one of Claims 1 to 8, characterized in that other, vertical, milling rolls arranged perpendicularly to the heated rolls and arranged in the roll-bending zone, are heated too.
10. Process according to any one of Claims 1 to 8, characterized in that pre-heating takes place on the feed side of the profiled section, namely in the region of the machine bridge.
11. Bending machine for carrying out the process according to any one of Claims 1 to 10, for the hot flow-form bending of thin-walled closed, half-open or open profiled sections with a bending head consisting of at least two rolls (17, 18) which are arranged opposite one another in the feed direction of the profiled section (21, 21') to be bent, and at an axial distance behind which in the feed direction at least one milling roll (14) and one opposing middle roll (11) are arranged which together constitute a roll-bending zone (40) for the profiled section (21, 21') to be worked, at least one bending roll (13) that can be traversed towards and away from the profiled section to be bent being arranged on the discharge side, characterized in that at least the rolls (11, 14) arranged in the roll-bending zone (40) are heatable.
12. Bending machine according to Claim 11, characterized in that, during operation, the profiled section (21, 21') to be worked is additionally propelled through the roll-bending zone (40).
13. Bending machine according to either of Claims 11 and 12, characterized in that a mandrel shank is provided, the mandrel shank (25) being heated in the region of the roll-bending zone (40) and constituting a support element (27) for the interior of the profiled section.
14. Bending machine according to Claim 13, characterized in that a link chain (28) consisting of individual articulated links that bear on the inner wall of the hollow profiled section is attached to the forward end of the mandrel shank (25), the said link chain (28) leading as far as the region of the bending roll (13).
15. Bending machine according to any one of Claims 11 to 14, characterized in that vertical milling rolls (15, 16) that bear on the upper and lower side walls of the profiled section are arranged in the region of the roll-bending zone (40).
16. Bending machine according to Claim 15, characterized in that the vertical milling rolls (15, 16) are heated too.
17. Bending machine according to any one of Claims 11 to 16, characterized in that, during operation, a current flows through the electrically conducting shell (41) of the milling roll (14) and through the electrically conducting profiled section (21) to be worked, and is led therefrom to the electrically conducting shell (41) of the middle roll (11).

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