DE102010046181B4 - Method for forming a cylindrical tubular body and arrangement for carrying out the method - Google Patents

Abstract

A cylindrical tubular body (1) is first pressed arcuately in the central longitudinal section (8) to form an oval cross-section on opposite sides in a preforming station. Then, the tube body (1) at least one end (7) in an offset to the longer cross-sectional axis (LQA) of the waisted middle length section (8) offset by 90 ° center longitudinal plane (MLE) in a forming station oval. This preformed tubular body (1) is then formed via its in the central longitudinal plane (MLE ₁ ) extending longer cross-sectional axis (LQA) to a pipe bend (19) and then further processing for the purpose of generating a tower pipe (2).

Description

On the one hand, the invention relates to a method for forming a cylindrical tubular body made of steel into a pipe bend according to the preamble of claim 1.

On the other hand, the invention is directed to an arrangement for carrying out the method according to the preamble of claim 5.

It belongs to the state of the art to transform cylindrical tubular steel bodies into pipe bends. Depending on the bending radius of the pipe bend, the formation of wrinkles on the inside of the pipe bend often leads to more or less pronounced deformation. However, such an appearance of a pipe bend is often undesirable both from an optical as well as in particular from a technical point of view, preferably in a so-called tower pipe, which is in the motor vehicle end of an axle body used and provided with a bearing bush, which carries the actual vehicle body ,

In the DE 600 07 618 T2 a method for forming a cylindrical hollow body of steel is described in a pipe bend, in which the tubular body is first pressed in the central longitudinal section on opposite sides so that the cross section of the tubular body assumes an approximately diabolo-shaped shape. Seen in the longitudinal direction of the tubular body receives this in the central longitudinal section of an approximately trapezoidal shape. Following the deformation of the central longitudinal section, the tubular body is bent around the shorter cross-sectional axis exclusively in this central longitudinal section. The end portions of the tubular body adjacent to the central longitudinal portion remain cylindrical and straight.

From the DE 197 49 369 A1 It is known to transform a cylindrical tubular body made of steel in a single manufacturing step in a pipe bend, which has at least partially an oval cross-section. For this purpose, the tube body is provided inside with a mandrel and then deformed in a pressing device with a lower die and two upper dies.

From the DE 37 42 869 A1 it turns out to form a cylindrical tube body at least one end in the warm state so that the tube walls lie flat on each other.

In the scope of JP 11 285 737 A It is state of the art to bend a cylindrical tube body in an end region at a slight angle and to deform this end region. The free end of the bent and deformed end portion is supported on an abutment. For deforming the end region displaceable mold jaws are used.

The invention is - based on the prior art - based on the object to provide a method for forming a cylindrical tubular body made of steel in a pipe bend and an arrangement for carrying out the method with which wrinkling on the inside of the pipe bend can be minimized relevant ,

As far as the procedural part of this task is concerned, its solution lies in the features of claim 1.

Advantageous developments of the method are the subject matter of claims 2 to 4.

In this method, in a first manufacturing step, a cylindrical tube body divided off from a tube drawn seamlessly or longitudinally welded in the middle longitudinal section is pressed in an arcuate manner on opposite sides to form an oval cross section on opposite sides. The tubular body is characterized on both sides of a central longitudinal plane quasi waisted and bulged on both sides of the offset by 90 ° mid-longitudinal plane. Subsequently, the waisted tubular body is rotated about its longitudinal axis by 90 °, so that the arcuate depressed areas are now located laterally of the Rohrköpers. The longer cross-sectional axis of the oval-shaped central longitudinal section now runs in the vertical central longitudinal plane of the tubular body. In a further production step, at least one end of the tubular body is flattened oval, in such a way that the longer cross-sectional axis of this oval-shaped end is offset by 90 ° to the longer cross-sectional axis of the oval central longitudinal section.

Now, the thus preformed tubular body is formed over the longer cross-sectional axis of the waisted middle length section to the pipe bend.

With this approach, wrinkling on the inside of the pipe bend can be at least significantly reduced, if not prevented, because there is a significantly greater flexural stiffness on the inside of the curved oval length portion as compared to a cylindrical cross section.

After forming the cylindrical tube body to the pipe bend this is fed to further processing.

Such a pipe bend is designed not only visually shapely, but also offers from a technical point of view all the positive conditions for the design of a tower pipe in Achsbau a motor vehicle.

The method according to the invention makes it possible to carry out all forming and shaping steps in a single device in a work station with respectively suitably adapted tools in several stations. This is associated with a considerable time and cost advantage.

Of course, the various processing measures of the process can also be made in various devices within a production line.

To ensure that the arcuate indentations are limited to the central longitudinal section of the tubular body, it is expedient that the oval waist of the central longitudinal section of the tubular body is carried out while maintaining its circular cross-sectional contours at the ends.

The quality of the pipe bend is inventively improved when the pipe bend is calibrated. This can be done in one processing stage or in several consecutive processing stages. Appropriately, the calibration takes place in a position of the pipe bend, in which extends the longer cross-sectional axis of its flattened oval end in a vertical plane. In this case, the ends of the pipe bend are nachgeschoben. Any bumps after bending are thus pushed away and the pipe bend made to measure. Such a method step is then associated with an additional time and cost advantage.

For the purpose of completing the pipe bend in the form of the aforementioned Tower Pipe, the oval-flattened end of the pipe bend is perforated. For this purpose, the pipe bend is brought into a position in which the longer cross-sectional axis of the oval end extends in a horizontal plane. The perforation may be continuous or only in one broad side of the oval end.

The solution of the subject portion of the invention of the underlying object seen in the features of claim 5.

Advantageous developments are subject matter of claims 6 to 12.

Such an arrangement is basically composed of a preforming station and a downstream forming station. Both stations can be combined in a single device. The forming station can also be arranged downstream of the preforming station in a production line.

The preforming station has a lower die and an upper die, which are relatively displaceable relative to each other. In addition, two transversely displaceable mandrels are part of the preforming station. After inserting a cylindrical tubular body made of steel in the preforming station, the support mandrels are inserted from the end faces into the ends of the tubular body. Subsequently, the upper and lower dies are moved toward one another, the middle longitudinal section extending between the ends remaining cylindrical on the basis of the mandrels being pressed in an arcuate manner on opposite sides and in this way waisted on both sides of a central longitudinal plane and bulging laterally on both sides of the central longitudinal plane offset by 90 ° becomes. The tubular body thus receives in the central longitudinal section permanently changing oval cross-sections.

The thus preformed in the central longitudinal section tubular body is now inserted into the forming station, consisting of a concave curved side, longitudinally gebuldeten bending tool, a lower mold cavity having a pressing jaw and a top side partially convex curved, partially horizontally extending, längsgemuldeten counter bearing and one of composed of the pressing jaw vertically displaceable support jaw and a pipe support at the lower end of the thrust bearing.

Bending tool, pressing jaw and counter bearing are relatively displaced relative to each other.

Become bending tool and press jaw moved in the horizontally extending portion of the thrust bearing tube body in the direction of the anvil, the press jaw first reaches the tube body and flattens the here lying end of the tubular body so oval that the longer cross-sectional axis of the flattened end in a order 90 ° to the longer cross-sectional axis of the oval shaped central longitudinal portion of the tubular body offset center longitudinal plane extends. Due to the relative displaceability of the bending tool to the pressing jaw, the bending tool can then continue to move in the direction of the anvil, then detects the oval central longitudinal section of the tubular body and deforms this over its longer cross-sectional axis to the pipe bend. Here, the pressing jaw holds the oval deformed end of the pipe bend, while the pipe support located at the lower end of the anvil fixes the other end of the pipe bend.

The displaceable by the pressing jaw support jaw serves to hold the cylindrical tube body so long on the horizontally extending portion of the thrust bearing until the pressing jaw has detected the tubular body. When deforming the pipe body to the pipe bend the support jaw is moved from the pressing jaw in the anvil.

When the preforming and forming stations are combined in one device, all movement operations are performed in parallel by means of a single deformation force (eg, press). There is then cyclically feeding a tubular body in the preforming station, the deformation of the tubular body in the preforming and forming station and ejection of the deformed tubular body from the forming station.

It is device-wise advantageous if the lower die of the preforming station arranged stationary and the upper die is vertically displaceable. In this way, the cylindrical tube body is pressed arcuately in the central longitudinal section from above and below and bulged in the transverse direction.

Also in the forming station, it is expedient that the anvil and the pipe support arranged stationary and the bending tool, the pressing jaw and the support jaw are vertically displaced.

The relative mobility between the pressing jaw and the bending tool of the forming station is ensured by providing at least one gas pressure spring between the pressing jaw and the bending tool.

An advantageous development of the inventive concept of the arrangement for carrying out the method is that the forming station is arranged downstream of a calibrating station with a stationary, top side dimpled lower tool with a vertically displaceable, underside dented upper tool and with the direction of movement of the upper tool transversely displaceable support pins. The reshaped tube sheet is placed in this calibration station for calibration so that the longer cross-sectional axis of the oval central length portion extends in a horizontal plane. The end retractable mandrels then serve to fix the pipe bend when it is calibrated when moving together of lower die and upper tool.

The calibration station can be integrated into a device together with the preforming station and the forming station. The calibration is then cyclically performed together with the feeding of a tubular body, the pre-forming and forming as well as the ejection.

However, the calibration station can also be arranged downstream of the forming station in a production line.

Preferably, the support mandrels are hydraulically displaceable.

In the case of a mechanical displacement of the support mandrels, it is expedient that the upper tool of the calibration station is subdivided into a shaping jaw and into a pressing plate which is distanced to the forming jaw by means of at least one gas spring.

The calibration can be carried out with a corresponding displacement of the support mandrels - individually or jointly - in one processing stage or in several processing stages.

Finally, it is still useful according to the invention that, to provide a complete tower pipe, a perforation station is provided with a top side concavely curved, longitudinally ducted pipe bend receiver, a horizontally displaceable mandrel and a vertically displaceable punch.

Such a perforation station can also be incorporated into the device with the preforming, the forming and the calibration, wherein all stations are each activated in a working cycle of a forming force.

However, it can also be arranged downstream of the calibration station in a production line.

The calibrated pipe bend is inserted into the pipe bend receptacle such that the longer cross-sectional axis of the oval middle length section extends in a vertical central longitudinal plane. Then, a mandrel is retracted into the oval flattened end of the pipe bend. Now, with the help of a vertically displaceable punch in the flattened end as needed in a broadside or in both broadsides a hole can be created. The mandrel may be perforated for this purpose.

The invention is explained in more detail with reference to exemplary embodiments illustrated in the drawings. Show it:

1a) -I) is a schematic representation of the forming of a cylindrical tubular body in a pipe bend provided with a hole at one end;

2 a schematic side view of a preforming station;

3 a schematic side view of a forming station in the open position;

4 the forming station of 3 in an intermediate position;

5 the forming station of 3 and 4 in closed position;

6 in schematic perspective, a calibration station and

7 also in a schematic perspective a hole station.

In the 1a) is with 1 a cylindrical tubular body made of steel. This pipe body 1 can be separated from a seamless drawn or longitudinally welded pipe string. A central longitudinal plane of the tubular body 1 is designated MLE and the 90 ° offset center longitudinal plane is MLE ₁ .

To produce one from the 1h) and i) recognizable tower pipe 2 as an end-part of an otherwise not shown axle body for motor vehicle construction of the tubular body 1 in one of the 2 recognizable preform station 3 with a fixed lower die 4 and with a vertically movable upper die according to the double arrow DPf 5 inserted. This is the upper die 5 moved up and the tubular body 1 in the lower genus 4 inserted. If then from the front sides of the tubular body 1 here cylindrical mandrels 6 in the ends 7 . 7a of the tubular body 1 retracted and the upper die 5 is acted upon by a force P, which is between the cylindrical ends 7 . 7a of the tubular body 1 located middle length section 8th from the top and bottom pressed to form an oval cross-section arcuate. The pipe body 1 then has a contour as seen from the 1b) is recognizable. The ends 7 . 7a of the tubular body 1 stay cylindrical. From these cylindrical ends 7 . 7a from then takes an oval deformation in the vertical transverse plane VMQE of the tubular body 1 has the largest lateral extent. In the central longitudinal plane MLE is the middle length section 8th pressed and bulged in the offset by 90 ° center longitudinal plane MLE ₁ .

The pipe body 1 according to 1b) Then, according to the arrow Pf around its longitudinal axis 9 by 90 ° in the position according to 1c) rotated, so that the longer cross-sectional axis LQA of the oval middle length section 8th in the now vertically aligned central longitudinal plane MLE ₁ extends. In this position, the tubular body 1 in one of the 3 to 5 recognizable forming station 10 introduced.

The forming station 10 initially has a fixed, top längsgemuldetes counter bearing 11 on, the upper side is partially curved convexly and extends partially horizontally. At the lower end of the convex curved area 33 of the counter bearing 11 is a stationary pipe support 12 , Further, in the horizontally extending area 13 of the counter bearing 11 a vertically movable support jaw 14 for a tubular body 1 intended.

To the forming station 10 further includes a vertically displaceable bending tool 15 which is longitudinally condoned on the underside and concavely curved. Relative to the bending tool 15 is vertically movable on the underside a mold cavity 16 having pressing jaw 17 arranged, with the pressing jaw 17 at least indirectly on the bending tool 15 via at least one vertically acting pressure spring 18 supported.

After inserting a centrally flattened tubular body 1 according to 1c) in the horizontal area 13 of the counter bearing 11 corresponding 3 aligning the longer cross-sectional axis LQA of the length section 8th of the tubular body 1 in the vertically aligned central longitudinal plane MLE ₁ becomes the bending tool 15 together with the press jaw 17 drove down until the pressing jaw 17 the tubular body 1 reached ( 4 ). Now the tube body 1 at the horizontal area 13 of the counter bearing 11 lying cylindrical end 7 due to the mold cavity 16 in the press jaw 17 as well as the contour in the horizontal area 13 oval flat pressed. The longer cross-sectional axis LQA _{1 of} the oval flattened end 7 then runs in the center longitudinal plane MLE ₁ offset by 90 °, horizontally oriented center longitudinal plane MLE ( 1d) ).

Upon further downward displacement of the bending tool 15 from the position according to 4 in the position according to 5 becomes the middle length section 8th of the tubular body 1 curved, being at the lower end of the anvil 11 the pipe support 12 in the flattened end 7 of the now formed pipe bend 19 according to 1e) opposite end 7a summarizes.

After opening the forming station 10 and taking out the pipe bend 19 this is according to the situation 1e) according to the arrow Pf ₁ by 90 ° in the position according to 1f) rotated, so that now the longer cross-sectional axis LQA of the oval length section 8th in the horizontally oriented center longitudinal plane MLE ₁ extends. In this position, the pipe bend 19 into the calibration station 20 according to 6 inserted.

This consists of a stationary, top-gebuldeten lower tool 21 , a vertically displaceable, undulating upper tool 22 and out to the direction of movement of the upper tool 22 transversely displaceable support mandrels 23 , When the mandrels 23 in the direction of the arrows Pf _{2 are} hydraulically displaceable, is the upper tool 22 integrally formed.

For a mechanical displacement of the mandrels 23 is the top tool 22 in a form of baking 24 and in a press plate 25 articulated by means of gas springs 26 distanced from each other.

When moving together upper tool 22 and lower tool 21 can the mandrels 23 in a certain way one after the other or together in the ends 7 . 7a of the pipe bend 19 be retracted, in which case the pipe bend in this way 19 calibrated in one processing stage or in several processing stages.

For the production of the Tower Pipe 2 according to the 1h) and i) the one from the calibration station 20 taken pipe bend 19 according to the arrow Pf3 again by 90 ° from the position according to 1f) in the position according to 1g) rotated, so that now the longer cross-sectional axis LQA of the oval middle length section 8th in the vertically aligned central longitudinal plane MLE ₁ extends.

In this position, the pipe bend 19 in the from the 7 recognizable perforation station 27 introduced. This consists of a concave curved, possibly multi-part, längsgemuldeten pipe bend recording 28 , a horizontally displaceable mandrel 29 and a vertically displaceable punch 30 together.

After inserting the pipe bend 19 in the pipe bend recording 28 becomes the mandrel 29 in the oval flattened end 7 of the pipe bend 19 introduced and then the punch 30 lowered from above, leaving in the end 7 a through hole 31 or a hole 31 in just one broadside 32 is produced.

The tower pipe 2 according to the 1h) and i) is finished.

LIST OF REFERENCE NUMBERS

1

pipe body

2

Tower pipe

3

preform station

4

Lowering v. 3

5

Upper Ges. 3

6

Support thorns v. 3

7

End of v. 1

7a

End of v. 1

8th

middle section v. 1

9

Longitudinal axis v. 1

10

forming station

11

Counter bearing v. 10

12

Pipe support v. 10

13

horizontal area v. 11

14

Supporting jaw on 11

15

Bending tool v. 10

16

Mold cavity 17

17

Pressing jaw v. 10

18

Gas springs v. 10

19

Elbows

20

calibration Station

21

Lower tool v. 20

22

Upper tool v. 20

23

Support thorns v. 20

24

Shape baking v. 22

25

Press plate v. 22

26

Gas springs v. 20

27

Loch station

28

Pipe bend intake v. 27

29

Mandrel v. 27

30

Punches v. 27

31

Hole in 7

32

Broadside v. 7

33

convex Bererich v. 11

DpF

double arrow

LQA

longer cross-sectional axis v. 8th

LQA ₁

longer cross-sectional axis v. 7

MLE

Mid-longitudinal plane v. 1 . 2 u. 19

MLE ₁

to MLE offset by 90 ° center longitudinal plane v. 1 . 2 u. 19

P

Power up 5

pf

arrow

Pf ₁

arrow

Pf ₂

arrow

Pf ₃

arrow

VMQE

vertical median transverse plane v. 1

Claims (12)

Method for forming a cylindrical tubular body ( 1 ) made of steel in a pipe bend ( 19 ), in which the tubular body ( 1 ) first in the middle section ( 8th ) is pressed arcuately to form an oval cross-section on opposite sides of the tubular body, and then at least one end ( 7 ) in one to the longer cross-sectional axis (LQA) of the oval waisted middle length section ( 8th ) is offset by 90 ° offset longitudinal center plane (MLE) oval, whereupon the preformed tubular body ( 1 ) in the central longitudinal plane (MLE1) of its longer cross-sectional axis (LQA) to the pipe bend ( 19 ) and this pipe bend ( 19 ) is subsequently supplied for further processing. A method according to claim 1, characterized in that the oval sidecut of the central length portion ( 8th ) of the tubular body ( 1 ) under Maintaining its at the ends ( 7 . 7a ) circular cross-sectional contours is performed. Method according to claim 1 or 2, characterized in that the pipe bend ( 19 ) is calibrated. Method according to one of claims 1 to 3, characterized in that the flattened oval end ( 7 ) of the pipe bend ( 19 ) is punched. Arrangement for carrying out the method according to one of Claims 1 to 4, characterized by a preforming station ( 3 ) with mutually relatively displaceable lower and upper dies ( 4 . 5 ) and two to the lower and upper 4 . 5 ) Transversely displaceable support mandrels ( 6 ) as well as through one of the preforming stations ( 3 ) downstream forming station ( 10 ) with a concave curved longitudinally gebuldeten bending tool ( 15 ), one of a lower mold cavity ( 16 ) having pressing jaw ( 17 ) and an upper side partially convexly curved, partially extending horizontally, längsgemuldeten counter bearing ( 11 ), wherein the bending tool ( 15 ), the pressing jaw ( 17 ) and the counter bearing ( 11 ) are relatively displaceable relative to one another, and one of the pressing jaw ( 17 ) sliding support jaw ( 14 ) and a pipe support ( 12 ) at the lower end of the anvil ( 11 ). Arrangement according to claim 5, characterized in that the lower die ( 4 ) of the preforming station ( 3 ) and the upper die ( 5 ) is vertically displaceable. Arrangement according to claim 5 or 6, characterized in that the abutment ( 11 ) as well as the pipe support ( 12 ) of the forming station ( 10 ) stationary and the bending tool ( 15 ), the pressing jaw ( 17 ) and the jaw ( 14 ) are vertically displaceable. Arrangement according to one of claims 5 to 7, characterized in that between the pressing jaw ( 17 ) and the press jaw ( 17 ) relatively movable bending tool ( 15 ) of the forming station ( 10 ) at least one gas spring ( 18 ) is provided. Arrangement according to one of claims 5 to 8, characterized in that the forming station ( 10 ) a calibration station ( 20 ) with a stationary, top-formed lower tool ( 21 ), with a vertically displaceable, undulating upper tool ( 22 ) and with the direction of movement of the upper tool ( 22 ) transversely displaceable support mandrels ( 23 ) is subordinate. Arrangement according to claim 9, characterized in that the support mandrels ( 23 ) of the calibration station ( 20 ) are hydraulically displaceable. Arrangement according to claim 9, characterized in that the upper tool ( 22 ) of the calibration station ( 20 ) in a shaping jaw ( 24 ) and in a by means of at least one gas spring ( 26 ) to form jaw ( 24 ) distanced pressing plate ( 25 ), wherein the mandrels ( 23 ) are mechanically displaceable. Arrangement according to one of claims 5 to 11, characterized in that the calibration station ( 20 ) a perforation station ( 27 ) with a top side concavely curved, längsgemuldeten pipe bend recording ( 28 ), a horizontally displaceable mandrel ( 29 ) and a vertically displaceable punch ( 30 ) is subordinate.

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