DE102015114345A1 - Progressively efficient tube expander and method for gradually expanding a tube - Google Patents

Abstract

In order to further develop known pipe expansion methods, the invention proposes a progressive tube expander having a progressively locally radially inwardly acting on a tube expander head, which is held on a support rod, and with displacement means for relative axial displacement of the expander head with respect to the tube, in which on the expander head at the axial height of the expander head an outer, an outer caliber forming outer matrix element is provided. Preferably, the expansion takes place by means of an effective hydroforming effective outside surface or are simultaneously applied Richtbiegekräfte.

Description

The invention relates to a stepwise effective tube expander with a progressively locally from radially inward acting on a tube expander head, which is held on a support rod, and with means for axial displacement of the expander head with respect to the tube.

The invention further relates to a method for gradually expanding a pipe.

Generic stepwise effective tube expander and method for gradually expanding a tube are known from the prior art.

For example, from the DE 22 58 359 A1 or even from the EP 2 535 124 A1 mechanically working pipe expander known, these mechanical Rohrxpander are subject to relatively high wear and can be used for pipes with smaller diameter, for reasons of space only with great restrictions.

Moreover, it is known to expand tubes by hydroforming processes, in which an entire tube, in practice usually in a tube testing press, is placed in a caliber shell and subjected to an internal pressure from the inside, so that it expands and creates the caliber shell from the inside. For pipe lengths of 10 m or more, this means correspondingly long caliber shells, in particular in pipes to be expanded with different geometrical dimensions, a corresponding set-up effort and very high equipment costs, in particular by a correspondingly complex tool park, or the use of each to be deformed and ultimately To be formed tube adapted shaped caliber shells condition.

Furthermore, it is for example from the DE 31 05 712 A1 or from the EP 0 215 294 B1 known to sealingly fit pipes in a pipe by locally from radially inward hydraulic pressure on the pipe piece, which is arranged axially at the level of the pipe, is applied until the pipe is pressed sealingly into the pipe. However, this approach is not suitable for the gradual expansion of pipes, in which the aim is pursued to widen the entire cross-section of the tube successively in the longitudinal extension of the tube.

It is an object of the present invention to provide a stepwise effective tube expander and a method for gradually expanding a tube, which can be used especially for smaller inner tube diameters.

The object of the invention is achieved by a stepwise effective tube expander and by a method for gradually expanding a tube with the features of the independent claims. Further, possibly also independent thereof, advantageous embodiments can be found in the subclaims and the following description.

By a stepwise effective tube expander with a progressively locally acting radially inward on a tube expander head, which is held on a support rod, and with displacement means for relative axial displacement of the expander head with respect to the tube can be a tube stepwise expand especially for small inner tube diameters if an outer outer element forming an outer caliber is provided at the axial height of the expander head.

This makes it possible to avoid complex control mechanisms with which locally the force applied from the inside is controlled in order to avoid an overshoot during expansion, which in turn can save installation space on the inside.

In order now to realize a stepwise effective, extremely small-build and less prone to wear Rohrxpander with a gradually acting locally from radially inward on a tube expander head, which is held on a support rod, as well as means for relative axial displacement of the expander head with respect to the tube on the one hand on the expander head a radially outwardly hydroforming effective effective surface and on the other hand at the axial height of the expander head an outer, an outer caliber forming outer matrix element may be provided.

This is based on the basic knowledge that a hydraulic arrangement requires much less space than a mechanical arrangement, especially if it must be applied with this correspondingly high expansion forces.

Thus, it is of considerable advantage that in particular the expansion head is designed to be many times shorter than the pipe to be expanded or as the ultimately expanded pipe section of the pipe. Already hereby different diameter expansion heads for expanding different pipe diameters can be provided significantly more economical in diameter than is the case with previously customary hydroforming. This also applies to corresponding outer matrix elements.

Due to the only piecewise expansion results in a stabilization achieved due to the non-flowing region of the remaining tube, which reduces uncontrolled flow of the tube material, in particular in the circumferential direction.

Advantageously, not only the expander head inserted in the tube but also simultaneously or else with a time delay moves the outer caliber or the outer matrix element stepwise in the direction of the longitudinal extent of the tube between the individual expansion phases. It goes without saying that it is only a question of a relative movement between the tube on the one hand and the expander head and the outer caliber or outer matrix element on the other hand. Usually, the latter are held stationary and moves the tube.

It is particularly advantageous, however, that the stepwise expansion proposed here allows extremely small expansion tools and the outer caliber to be extremely dimensionally stable.

Accordingly, it is advantageous if in particular the expander head is arranged on a support rod, which is sufficiently long, otherwise a gradual displacement of the expander head within the tube is difficult to implement. It is particularly advantageous if the length of the support rod is at least five times, preferably at least ten times, of the maximum achievable by the expander head inner tube diameter.

It goes without saying that the outer matrix element forming the outer caliber can be embodied in many different ways in order to enclose the tube to be expanded from the outside in such a way that a suitable counter-pressure surface can be provided for the active surface which has a hydroforming effect radially outward.

The outer matrix element can in this case also be designed as a tube, if this relaxed sufficiently elastic inward at an expander head side pressure drop and thereby a relative movement between the outer caliber and the tube to be expanded or the expanded tube is again possible.

Are provided in the area of the effective surface of the expander head means for generating a hydroforming locally effective internal pressure on a tube to be expanded, the radially outwardly hydroforming effective effective surface can be generated very easily and compactly on the expander head.

It is understood that such internal pressure generating means can be realized constructively diverse, for example, they may include flexible pressure pad elements which can act between the inside of the tube to be expanded and the lateral surface of the expander head.

Thus, the internal pressure generating means may comprise at least one flexible active element, which is arranged in the region of the hydroforming effective effective area and forms. Due to the flexibility, a corresponding effect, which corresponds to an immediate hydraulic loading, can be achieved. Depending on the concrete implementation, however, the flexible active element may have a stabilizing effect in the circumferential direction in order to minimize the risk of uncontrolled flow in this direction.

An effect that corresponds to an immediate hydraulic loading can be ensured in particular when the flexible active element is acted upon on its side facing away from the pipe with a hydraulic pressure. The flexible operative element may then follow any movements, such as the fluid providing the hydraulic pressure.

Advantageously, the internal pressure generating means comprise a machined on the outer surface of the expander head Materialausnehmung, which preferably extends concentrically around the axial displacement axis of the expander head around. This allows a simple and controlled pressure build-up of the internal pressure.

The present internal pressure generating means may at least partially be made rigid by the expander head per se, if they comprise a pressure trough which is incorporated on the lateral surface of the expander head.

In particular, the flexible active element can seal a material recess filled with hydraulic fluid as a sealing element. This can be ensured, for example, that the flexible active element ranging from a wall of the material recess to another wall. Optionally, a relative movement between the flexible active element and the Materialausnehmung be provided as long as a sufficient tightness is ensured.

Sufficient tightness can then be achieved, for example, by the fact that the hydraulic pressure acts on the flexible active element and presses it against the wall of the material recess. Depending on the specific implementation, sealing lips or the like can be provided on the flexible active element with which the sealing effect can be enhanced.

The present active surface, which can be generated approximately by a substantially rigidly configured on the expander head Materialausnehmung, can also be structurally sealed at their axial end regions opposite adjacent components or areas of Rohrxpanders or the like, if the active surface between two axially spaced apart, circumferential Sealing elements are arranged. Depending on the specific configuration of the sealing elements can be dispensed with a configuration of the internal pressure generating means in the form of a pressure pan or a Materialausnehmung if all axial forces can be compensated by the sealing elements.

In a specific embodiment, the active surface is surrounded by sealing elements, which are expandable in the radial direction. In order to be able to adapt well to a radial spatial expansion of the tube to be expanded, it is advantageous if the sealing elements are radially adjustable, preferably hydraulically adjustable. As a result, the sealing elements can always be kept nestled snugly against the inside of the expanding tube, in particular even before the actual expansion, while already a pressure is built up.

For example, these sealing elements and / or the flexible active elements can be realized by expandable, and possibly also hollow, upholstery elements which, depending on a progressive radial tube expansion, increase their body volume and subsequently reduce it again. Depending on the specific embodiment, elastic elements may still be incorporated into the sealing or flexible active elements, which can stabilize them and apply any return forces. In particular, these elements are made of polyurethane elastomer may, for example, cross-linked polyurethane elastomer, highly elastic polyurethane elastomer and / or produced by polyaddition polyurethane elastomer, such as comprise in particular Vulkollan ^®.

Structurally simple and robust, these sealing elements can be implemented if they comprise a flexible sealing body, which consists at least partially of a flexible solid material, such as an elastomer.

This flexible sealing body can in this case be lengthened in a suitable manner by radially inwardly acting forces or by pressurization in the circumferential direction of the expander head, so that it always conforms to this tube in a radial expansion of the tube. In this case, the respective sealing element can rejuvenate with respect to its cross-section the more the expansion of the tube progresses.

So that the sealing elements can always be sufficiently supported on the expander head during radial adjustment, it is advantageous if these sealing elements are each arranged in a sealing element groove, which are arranged spatially axially separated from the pressure trough.

A particularly good axial tightness of the radially outwardly effective hydroforming active surface can be ensured if both this active surface or the relevant Materialausnehmung or the pressure pan and the Dichtelementenuten each have their own pressure line for supplying hydraulic fluid.

In this respect, it is expedient if the leading to the pressure trough pressure line is different from the Dichtelementenuten, it can be ensured that the sealing elements are less heavily burdened in particular in the axial direction by the pressurization.

Preferably, this leading to the pressure pan or to the internal pressure generating means pressure line is arranged axially spaced from the Dichtelementenuten.

In this case, the pressure line leading to the pressure trough or to the internal pressure generating means is preferably arranged between two axially spaced-apart sealing elements of the present seal.

However, such an arrangement can be dispensed with if a flexible active element is also used as a sealing element. Then preferably the hydroforming locally effective internal pressure serves as a pressure for sealing.

As already described, the outer matrix element can be realized with a suitable configuration or sufficiently elastic tubes as a tube which is continuous on the circumference.

However, the outer matrix element can be configured much more easily assembled or disassembled, and thus displaceable with respect to the tube, if the outer matrix element comprises at least two radially separable partial elements each carrying a partial caliber.

With the present tube expander, despite the separable sub-elements of the outer matrix element good shape retention of the expanding tube can be ensured if a gap is provided between the partial calibers, which is preferably smaller than a by or Applicable internal pressure conditional bending radius is. This also allows greater flexibility in terms of process control and in terms of the pipe diameter to be achieved, since the gap can be varied within certain limits, as long as the desired tolerances can be maintained.

Preferably, the tube expander comprises means for applying straightening forces. During expansion, the expanding material is already subjected to very high stresses, so that when additional bending forces in the tube longitudinal direction are superimposed on the expansion forces or applied to the pipe, may be smaller.

In particular, the directional bending forces can be applied as 3- or 4-point bending forces, which allows targeted straightening.

Thus, the application means for applying the directional bending forces radially displaceable to each other and axially spaced bending stamps include, with which then the directional bending forces can be applied.

The bending punches preferably have contact surfaces adapted to the tube, so that markings of the tube can be kept to a minimum.

The bending punches may in particular also comprise the outer matrix element (s), which in any case have contact surfaces adapted to the tube and can be found in the expanding region. Possibly. For example, the application means may comprise means for tilting the outer matrix member with respect to the tube, with respect to other bending dies, and with respect to the expander head, respectively. Possibly. can also be formed axially divided the outer matrix element, wherein, if necessary, a gap between the axial parts may be provided, so that by appropriate axial bending or by tilting corresponding directional bending forces can be applied.

Also, with as little wear as possible, especially with smaller inner tube diameters, expansion of a tube can be realized by a stepwise expansion method of a tube as the tube progressively expands by means of an expander head acting locally from radially inner to outer caliber, and both outer caliber and crotch per step the expander head is displaced axially with respect to the tube.

In this case, there is an expansion of radially inward against the outer caliber, which can happen mechanically or hydroforming from inside especially small inner diameters without great regulations or exact dimensional accuracy. Due to the outer caliber, the required dimensional accuracy can be ensured, so that the expander head can be correspondingly simple.

In this case, the tube is displaced in relation to the expander head and the outer caliber or the outer matrix element stepwise in the longitudinal direction of the tube so that they are arranged in the radial direction with respect to the longitudinal direction of the tube axially at the same height.

Subsequently, the expander head is activated mechanically or by its radially outwardly hydroforming effective effective surface and the tube in the section in which the expander head and the outer caliber are arranged locally expanded radially outward in the direction of the outer caliber.

The pipe section of the tube to be expanded located between the expander head and the outer caliber is therefore locally expanded against the outer caliber.

Due to the stepwise expansion, a corresponding widening of the preferably entire tube takes place overall, whereby on the one hand the dimensional stability of the entire tube and on the other hand the material properties of the entire tube are advantageously influenced accordingly.

As a rule, the tubes are then further used as semi-finished tubes after the expansion and adapted for their actual purpose.

A displacement of the outer caliber in the axial direction of the longitudinal extent, in particular of the already expanded tube can be made with little effort and reliable, when the outer caliber before an axial displacement, preferably by opening the outer caliber providing partial caliber, is opened. In addition, this can also reduce the risk of mechanical damage to the outside of the tube to be expanded when the outer caliber is temporarily expanded by opening the part caliber with respect to its inner diameter.

In order to be able to temporarily spatially and sealingly separate the effective radially outwardly active surface from a gap existing between the expander head and the tube to be expanded, it is particularly advantageous in terms of process engineering if, prior to local expansion, a seal between the expander head and the tube is closed, preferably by sealing elements are subjected to a closing form, is.

As already explained above, a sufficiently high sealing of the radially outwardly hydroforming active surface against the existing between the expander head and the tube to be expanded gap can be achieved structurally simple within the tube when an admission side of the seal is subjected during expansion with the expansion pressure ,

The loading side of the respective sealing element of the seal is preferably the side of this sealing element facing the expander head, which is arranged radially further inwards than the side facing the tube.

In particular, the respective sealing element can be embedded in the expander head in such a way that on the one hand the radially outwardly effective active surface is sealed in the axial direction and on the other hand a primary pressure line is sealed in the radial direction, so that each of the sealing elements meets a double-sealing function of different hydraulic spaces on structurally compact space.

In particular, a directional bending can take place during the expansion, which can be energetically favorable if, in this case, the stresses which are already present in the material during the expansion are used accordingly in order to also make bends there. Preferably, for this purpose, corresponding bending forces are additionally superimposed in the pipe longitudinal direction of the expansion forces, which can be done for example by axially spaced-apart bending punch.

As a punch, for example, the outer matrix elements or the outer caliber can be used, especially if they are divided axially. The utilization of the outer matrix elements or the outer caliber as a bending punch is also advantageous insofar as they are axially displaceable in general anyway for tightening and adjusting. Possibly. For this purpose, additional inclination means can be provided, with which the outer matrix elements or the outer caliber can be inclined with respect to the tube axis, the other bending elements or the expander head. This also bending forces can be applied.

It is understood that the features of the solutions described above or in the claims can optionally also be combined in order to implement the advantages in a cumulative manner.

Further advantages, objects and features of the present invention will be explained with reference to the following description of exemplary embodiments, which are shown in particular in the appended drawing. In the drawing show:

1 a schematic sectional view in the axial direction along the in 2 indicated line II by a progressive tube expander with an expander head comprising a radially outwardly hydroforming effective effective surface and at the axial height of the expander head an outer, an outer caliber forming outer matrix element;

2 a schematic sectional view of the in the 1 shown Rohrxpanders in the radial direction along the line II-II 1 ;

3 a schematic further sectional view of the pipe expander after the 1 and 2 in a similar representation as 2 with open outside caliber;

4 a schematic sectional view of the tube expander with an alternative outer matrix element in a similar representation as 2 ;

5 a schematic sectional view of the pipe expander according to 4 in a similar representation as 3 with open outside caliber;

6 a schematic sectional view through a second stepwise tube expander in a similar representation as 1 ;

7 a schematic sectional view through a third stepwise pipe expander in a similar representation as 1 and 6 ; and

8th a schematic sectional view through a fourth stepwise tube expander in a similar representation as 1 . 6 and 7 ,

The in the 1 to 3 shown stepwise effective tube expander 1 includes an expander head 10 which is in a radial direction 5 to be expanded pipe 2 introduced and for radial expansion of this tube 2 gradually in the axial direction 6 relative to the tube 2 is relocated.

The expander head 10 This is on a relatively long support rod 22 of the stepwise effective pipe expander 1 held, allowing a relative movement between the expander head 10 and the pipe to be expanded 2 without any problems even with very long pipes 2 can be implemented.

To initiate such relative movement between the expander head 10 and the tube 2 has the stepwise effective tube expander 1 via appropriate means of displacement 24 , By means of which in this embodiment, the tube to be expanded 2 in the axial direction 6 is movable while at the same time the expander head 10 using the carrying rod 22 can be held in a fixed position.

For this purpose, in this embodiment, the displacement means 24 exemplarily a plurality of axial transport rollers 26 on which of radially outward on the lateral surface 3 of the pipe 2 can be frictionally fitted, so that the pipe 2 in the axial direction 6 moved and relative to the stationary held expander head 10 can be displaced when at least one of the Axialtransportwalzen 26 is driven according to rotational. In an alternative embodiment, a gripper carriage may be provided for the axial transport.

In addition, the stepwise effective tube expander includes 1 another outer, an outer caliber 30 forming outer matrix element 40 which is used to expand the tube 2 always at the axial height 31 the expander head 10 is positioned so that the expander head 10 and the outer matrix element 40 during the expansion of the pipe 2 radially next to each other and axially at the same height 31 are arranged.

The outside caliber 30 thus gives the one with the outer matrix elements 40 maximum achievable expansion diameter of the pipe 2 less elastic recoil of the pipe 2 after the expansion process.

The outer matrix element is in this case by at least two radially separable, in each case a partial caliber 35 carrying partial elements 45 configured, which at their opposite ends 39 (only exemplified) through a gap 38 (only exemplified) are separated from each other.

The respective gap 38 is still in this embodiment by a respective one between the two sub-elements 45 placed spacers 48 (quantified only as an example). Alternatively, other designs may be provided here.

Furthermore, the respective gap 38 smaller in this embodiment than one by one against the part caliber 35 Applied or applicable internal pressure induced bending radius of the part caliber 35 ,

As according to the arrangement 4 and 5 can be shown on the gap 38 and the spacers 48 , which the gap width of the respective gap 38 guarantee, if necessary, be waived, so that can be easily formed.

In any case, during expansion, the tube to be expanded becomes 2 against the outside caliber 30 which is the pipe 2 in the area of the outer matrix element 40 in the circumferential direction 4 of the pipe 2 encloses, pressed, after the elastic recoil of the tube 2 on the intended expansion diameter of the pipe 2 to get.

A requisite, hydroforming locally effective internal pressure is by a radially outwardly hydroforming effective effective area 12 provided, which in turn by means of the expander head 10 is provided and around this in the circumferential direction 4 Umlauft.

These are especially in the field 11 the expander head 10 medium 14 for generating the hydroforming locally effective internal pressure on a tube to be expanded 2 provided, the effective area 12 especially through a material recess 15 is formulated which outside on the peripheral side 13 the expander head 10 is worked out.

The material recess 15 designed a pressure pan 18 on the expander head 10 from, wherein one for generating the effective area 12 or the hydroforming locally effective internal pressure hydraulic fluid 19 from the pressure pan 18 can be included.

In the expander head 10 is a pressure line 16 brought in, so this hydraulic fluid 19 from an expansion pressure pump 62 the internal pressure generating means 14 through the expander head 10 through to the pressure screen 18 can be promoted.

Structurally particularly simple is the pressure line 16 at the remote expansion pressure pump 62 fluidly connected, since the pressure line 16 with a pressure line section 20 until by carrying rod 22 passed through.

The carrying rod 22 is at the expansion pressure pump 62 then only by means of a relatively short flexible pressure hose 21 fluidly connected, which can be implemented differently in different embodiments, for example by a rigid pipe or by an immediate connection.

The in the pressure pan 18 conveyed into hydraulic fluid 19 is in the axial direction 6 opposite one between the expander head 10 and the pipe inside 7 of the pipe 2 existing gap 8th in all phases of the expansion process by a correspondingly formed seal 50 sealed.

This seal 50 includes two axially spaced, on the expander head 10 in the direction of rotation 4 circumferentially mounted sealing elements 54 (only exemplified), which at the axial ends 58 the radially outwardly hydroforming effective effective surface 12 are provided.

The respective sealing element 54 this sits in a sealing groove 59 , which on the expander head 10 is inserted all around.

To the radially outwardly hydroforming effective effective surface 12 regardless of the width of the gap 8th and / or in the pressure pan 18 prevailing pressure conditions always good to seal against the environment, are the sealing elements 54 designed radially adjustable.

In this embodiment, such a radial adjustability is structurally simple in that the sealing elements 54 hydraulically in the radial direction 5 are adjustable.

For this purpose, the sealing grooves 59 by a pressure line 56 with a pre-pressure pump 61 fluidly connected. The form pressure line 61 This is both from the expander head 10 as well as from the carrying rod 22 designed, with the support rod 22 by means of another flexible pressure hose 57 at the pre-pressure pump 61 is fluidly connected, which also in different configurations also readily different, for example, by rigid lines or by a direct connection, can be implemented.

Thus, the sealing elements 54 from radially inward with a pressurized hydraulic fluid 19 acted upon and thus, if necessary, radially outward against the pipe inside 7 of the pipe 2 pressed or hired.

The present internal pressure generating means 14 are constructively connected, since both the pre-pressure pump 61 as well as the expansion pressure pump 62 each their hydraulic fluid 19 from a common pool of liquid 63 can relate.

Here are the downstream of the pre-pressure pump 61 and the expansion pressure pump 62 arranged flexible pressure hoses 57 and 58 by means of a check valve 64 fluidly connected to one another, so that a pressure equalization can take place in order to ensure a sufficient tightness of the seals.

To gradually expand the tube 2 becomes the expander head 10 in the pipe 2 introduced and inside the tube 2 at the area of the tube to be expanded 2 positioned.

The outer caliber element 40 is or is at an axial height 31 the expander head 10 positioned so that the outside caliber 30 of the outer caliber element 40 the pipe 2 encloses the outside. After expanding, the tube becomes 2 shifted axially by one step.

In this respect, in this embodiment, each step, both the outer caliber 30 as well as the expander head 10 axially with respect to the tube 2 relocated.

It is understood that in different implementations, first the outer caliber element 40 and then the expander head 10 or vice versa to the pipe 2 can be relocated. In general, the pipe will 2 in relation to the expander head 10 and the outer caliber element 40 relocated.

Here is the outer caliber element 40 as shown in the 2 still in the open state.

For the actual expansion process, the outer caliber element 40 but then transferred to a closed state, as this as shown in the 3 is shown.

Then it is over the pre-pressure pump 61 on the admission side 55 the sealing elements 54 given a form, leaving the seal 50 is closed. This presses the hydraulic fluid 19 from inside against the sealing elements 54 that these sealing elements 54 depending on the itself in the form pressure line 56 constructive pressure more or less intense against the pipe inside 7 of the pipe 2 be pressed.

Is now the seal 50 sufficiently close to the pipe 2 Employed, the pressure pan 18 via the expansion pressure pump 62 with the hydraulic fluid 19 and pressurized, wherein when the admission pressure is exceeded, the check valve 64 opens and thereby the pressure on the supply side 55 the sealing elements 54 is given, so the seal 50 interactively with the expansion pressure of the pipe expander 1 can be adjusted. This always guarantees that the seal 50 also seals against the high expansion pressure.

Possibly. can also be provided a venting of the sealed volume, especially when water is used to apply the hydroformenden internal pressure.

Is the expansion process regarding the pipe 2 in the area of the effective area 12 takes place, the pre-pressure for adjusting the seal 50 and the expansion pressure for expanding the tube 2 , but also for further hiring the seal 50 , reduced, so that the expander head 10 further in the axial direction 6 relative to the tube 2 can be relocated.

Accordingly, the sub-elements 45 of the outer matrix element 40 or the relevant partial caliber 35 at least as far away from each other that even the outside caliber 30 easily against the pipe 2 can be displaced, in particular relative to the previously expanded region of the tube 2 ,

According to the representations after the 4 and 5 is an alternative outer matrix element 140 which is used instead of the outer matrix element described above 40 at the present stepwise effective tube expander 1 and in cooperation with the expander head 10 can be used.

This alternative outer matrix element 140 consists of three sub-elements 145 (only exemplified), which in the assembled state (see 4 ) of the outer matrix element 140 together the outside caliber 130 form.

Here are the sub-elements 145 one partial caliber each 135 (only exemplified) of the Außenkalibers 130 , so a total of three partial caliber 135 of the outside caliber 130 ,

Through this three-part structure can insbesondre to a gap 38 (please refer 2 and 3 ) or spacers 48 between the individual subelements 145 be waived, as these still in the in the 1 to 3 shown solution with respect to the outer matrix element 40 are provided.

As can be seen immediately, the means by which the outer matrix element 40 . 140 can be opened and closed, also be used to the outer matrix element 40 . 140 in the radial direction 5 in terms of relocating means 24 to shift, so hereby bending forces can be applied especially during expansion. In addition to this are inclinations 75 (indicated only by a double arrow), with which the outer matrix element with respect to the axial direction 6 or the tube axis or the expander head 10 can be inclined, which also Richtbiegekräfte can also be applied.

Thus, in these embodiments, both the displacement means 24 as well as the outer matrix elements 40 . 140 as a punch 71 and thus together, or possibly the outer matrix elements 40 . 140 even alone, as a means of application 70 be used for applying directional bending forces, which can happen especially during expansion.

As can be seen immediately, the outer matrix element is 40 in his contact area 75 to the pipe 2 the shape of the pipe 2 customized. Also for the contact surface 75 the Axialtransportwalzen 26 with the pipe 2 a corresponding form can be selected.

The in the 6 to 8th illustrated embodiments essentially correspond to the embodiment according to 1 , so that identical acting assemblies are numbered identically.

In deviation from the embodiment according to 1 prove the embodiments 6 to 8th a flexible active element 51 on which between the hydraulic fluid 19 and the tube 2 on the expander head 10 is arranged and at the same time as a sealing element 54 serves. This consists in the present embodiments of Vulkollan ^® , but may also consist of other materials, as long as they are sufficiently stable and elastic at the same time.

The flexible active element 51 gets on its inside with the hydraulic fluid 19 acted upon, so this over the flexible active element 51 hydroforming from the inside to the pipe 2 can work.

According to the embodiment 6 is the flexible active element 51 firmly with the rest of the expander head 10 while it according to the embodiments 7 and 8th respectively in this regard or in relation to the material recess 15 is displaceable or expandable.

For sealing purposes, the flexible active element 51 of the embodiment according to 7 Sealing lips (not numbered), which are printed by the pressure of the hydraulic fluid to the outside axially and thus have a sealing effect. According to the embodiment 8th becomes the pressure-induced axial expansion of the flexible active element 51 used as a seal.

As hydraulic fluid 19 In particular, an emulsion of water and oil in question.

According to the embodiment 6 become the relocating means 24 not as a stamp 71 used. Instead, it's a bending punch 71 provided, which is similar to the outer matrix element 40 is formed and accordingly axially and in its inclination angle is changeable. This can be done with the help of Outside matrix element 40 be applied according to directional bending forces, preferably this additional bending punch 71 in the direction of the expansion steps in front of the outer matrix element 40 lies, so that attaches first to the unprocessed pipe.

According to the embodiment 7 is one of two sub-matrices 41 . 42 existing outer matrix element 40 provided, which the application means 70 form and both axially and in their angle of inclination to each other or to the tube axis or the expander head 10 are adjustable.

The embodiment according to 8th instead uses separate complementary bending punches 71 extending from radially inward to the pipe 2 act on the expander head 10 are attached and together with the outer matrix element as applying means 70 Act. It is understood that even these supplementary bending punch contact surfaces 75 have the tube 2 are adapted in shape.

Depending on the specific embodiment, the above explained with reference to different embodiments application means 70 or used for expansion facilities are also combined in different embodiments.

 It should be explicitly pointed out at this point that the features of the solutions described above or in the claims and / or figures can optionally also be combined in order to be able to implement or achieve the explained features, effects and advantages in a cumulative manner.

 It is understood that the exemplary embodiments explained above are only first embodiments of the invention. In this respect, the embodiment of the invention is not limited to these embodiments.

LIST OF REFERENCE NUMBERS

1

tube expander

2

pipe

3

lateral surface

4

circumferentially

5

radial direction

6

axial direction

7

Pipe inside

8th

gap

10

expander head

11

Area

12

effective area

13

peripheral side

14

Pressure generating means

15

material recess

16

pressure line

18

pressure trough

19

hydraulic fluid

20

Pressure line section

21

pressure hose

22

carrying bar

24

displacement means

26

Axialtransportwalzen

30

outside caliber

31

axial height

35

part caliber

38

gap

39

Ends (numbered as an example)

40

Outside matrix element

41

submatrix

42

submatrix

45

subelement

48

spacer

50

poetry

51

flexible active element

54

 Sealing element (numbered as an example)

55

Beaufschlagungsseite (numbered as an example)

56

priming lines

57

further pressure hose

58

axial ends

59

 Sealing grooves (numbered as an example)

61

booster pump

62

Expansion pressure pump

63

liquid storage

64

check valve

70

application means

71

punch

72

contact area

75

inclining means

130

outside caliber

135

part caliber

140

alternative outer matrix element

145

partial elements

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 2258359 A1 [0004]
• EP 2535124 A1 [0004]
• DE 3105712 A1 [0006]
• EP 0215294 B1 [0006]

Claims (17)

Step by step effective tube expander ( 1 ) with a stepwise local from radially inner to a tube ( 2 ) acting expander head ( 10 ) mounted on a carrying rod ( 22 ), as well as with relocating means ( 24 ) for relative axial displacement of the expander head ( 10 ) with respect to the pipe ( 2 ), characterized in that at axial height ( 31 ) of the expander head ( 10 ) an outer, an outer caliber ( 30 ; 130 ) outer matrix element ( 40 ; 140 ) is provided. Tube expander ( 1 ) according to claim 1, characterized in that on the expander head ( 10 ) a radially outwardly hydroforming effective effective area ( 12 ) is provided. Tube expander ( 1 ) according to claim 2, characterized in that in the region of the active surface ( 12 ) on the expander head ( 10 ) Medium ( 14 ) for generating a hydroforming locally effective internal pressure on a tube to be expanded ( 2 ) are provided. Tube expander ( 1 ) according to claim 3, characterized in that the internal pressure generating means ( 14 ) at least one flexible active element ( 51 ), which in the region of the effective hydroforming effective surface ( 12 ) is arranged and this forms and which in turn on its the pipe ( 2 ) facing away from a hydraulic pressure can be acted upon. Tube expander ( 1 ) according to claim 4, characterized in that the flexible active element ( 51 ) one with hydraulic fluid ( 19 ) filled material recess ( 15 ) as a sealing element ( 54 ) seals. Tube expander ( 1 ) according to one of claims 2 to 5, characterized in that the active surface ( 12 ) between two axially spaced, circumferential sealing elements ( 54 ) is arranged and the sealing elements ( 54 ) are preferably radially adjustable, preferably hydraulically adjustable, are. Tube expander ( 1 ) according to one of claims 1 to 6, characterized in that the outer matrix element ( 40 ; 140 ) at least two radially separable, one partial caliber ( 35 ; 135 ) carrying partial elements ( 45 ; 145 ). Tube expander ( 1 ) according to one of claims 1 to 7, characterized in that the outer matrix element ( 40 ; 140 ) at least two axially spaced-apart part matrices ( 41 . 42 ) for applying straightening forces, which are preferably displaceable radially to one another. Tube expander ( 1 ) according to claim 7 or 8, characterized in that between the partial calibers ( 35 ) or the sub-matrices ( 41 . 42 ) A gap ( 38 ), which is preferably smaller than a bending radius caused by an applied or applied internal pressure. Tube expander ( 1 ) according to one of claims 1 to 9, characterized by means ( 70 ) for applying straightening forces. Pipe expander according to claim 10, characterized in that the application means ( 70 ) radially displaceable and axially spaced from each other bending punch ( 71 ), in particular the pipe ( 1 ) adapted contact surfaces ( 72 ) and preferably also the outer matrix element ( 40 ). Pipe expander according to claim 10 or 11, characterized in that the application means ( 70 ) Medium ( 75 ) for tilting the outer matrix element ( 40 ) with respect to the pipe ( 2 ) or on the expander head ( 10 ). Method for progressively expanding a pipe ( 2 ), characterized in that the tube ( 2 ) stepwise by means of a local from radially inner to an outer caliber ( 30 ; 130 ) acting expander head ( 10 ) and with each step the outer caliber ( 30 ; 130 ) as well as the expander head ( 10 ) axially with respect to the tube ( 2 ) are relocated. Method according to claim 13, characterized in that the outer caliber ( 30 ; 130 ) before axial displacement, preferably by opening the outer caliber ( 30 ; 130 ) partial calibres ( 35 ; 135 ), is opened. A method according to claim 13 or 14, characterized in that prior to local expansion first a seal ( 50 ) between the expander head ( 10 ) and the pipe ( 2 ), preferably by sealing elements ( 54 ) are applied with a closing form, is. Method according to one of claims 13 to 15, characterized in that an admission side ( 55 ) of the seal ( 50 ) is subjected to the expansion pressure during expansion. Method according to one of claims 13 to 16, characterized in that during local expansion straightening takes place by preferably additional bending forces in the tube longitudinal direction superimposed on the expansion forces or on the tube ( 2 ).

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