DE102013005685A1 - Method and forming device for a wire shaped article and wire shaped article - Google Patents

Abstract

The invention relates to a method for producing a shaped wire body, in which a precursor produced from at least one wire is compressed by a forming device in the axial direction, wherein the precursor is at least partially radially outwardly widened against a negative mold of the forming device such that it has its final outer shape gets. According to the negative mold is at least partially entrained during the upsetting so that frictional forces are prevented at least between the widening portion of the precursor and the moving portion of the negative mold, the frictional forces at least but against the axial movement of the precursor, which undergoes the precursor during compression, are reduced.

Description

The invention relates according to the preamble of claim 1, a method for producing a wire shaped body in which a manufactured from at least one wire precursor is compressed by a forming device in the axial direction, wherein the precursor is at least partially expanded radially outwardly against a negative mold of the forming device that it gets its final outer shape. Furthermore, the invention relates to a forming device according to the preamble of claim 9 and a wire shaped body according to claim 11.

The production of shaped wire bodies has long been known. Usually, a precursor made of wire, for example, a wire-knitted tube portion, a wire-wound or wire-wound wire-wound wire cylinder, or the like, is provided as a preliminary product. As a precursor in the context of the present application, semi-finished products are understood that have already been plastically deformed in upstream forming steps, for example, to specifically form material compaction, but not yet have their final shape.

The precursor is reshaped by means of plastic deformation in a correspondingly formed forming device for the finished wire shaped body. The shaping device is for this purpose equipped with a negative mold which is complementary to the finished outer shape of the finished wire shaped body.

As is shown time and again, in particular when forming precursors with a comparatively large axial length, which are compressed during deformation in their axial length, irregularities in the structure often occur in the finished shaped article. The shaped wire body varies in its compression over its axial length and thus, for example, in its flow resistance when the shaped wire body is used, for example, as a filter insert.

Based on this prior art, it is an object of the invention to provide a method or a forming device for producing a shaped wire with which or in their use a wire molding is produced having viewed over its length at least approximately constant compression.

According to the invention, this object is achieved by a method having the features according to claim 1 and in particular that the negative mold is at least partially carried along during the upsetting that frictional forces prevented at least between the widening portion of the precursor and the moving portion of the negative mold, the Frictional forces are reduced at least but compared to the axial movement of the precursor, which undergoes the precursor during compression, are reduced. Furthermore, the object is achieved by a forming device with the features of claim 9.

By using a variety of stamps, negative molds and various controls the forming operations was trying to eliminate the irregularities in the compaction of the finished wire molding, but this was not successful. A detailed analysis of the above-mentioned problem revealed that the irregularities in the compaction of the finished shaped wire body were caused by the frictional forces arising during the forming between the outer surfaces of the precursor and the inner surfaces of the negative mold. Thus, the precursor is not only compressed during the axial compression, but at the same time expanded radially in sections. The expansion of the precursor during forming is hardly controllable, but occurs at different points in the longitudinal direction of the precursor considered. As a result, between the expanded sections of the precursor and the inner wall of the negative mold to a significantly increased friction, which in turn, due to the compressive forces counteracting frictional forces, leads to an unintended support effect on the expanded portions of the precursor. As a result, the precursor in the places where it is already expanded, additionally compressed, while adjacent portions of the precursor, which are not yet expanded, less compacted. For this reason, the final finished product, viewed over its axial length, has a varying compression of the wire structure of the wire shaped body.

According to the invention, it is now proposed to carry the negative mold at least in sections during the compression of the preliminary product in such a way that frictional forces are prevented, or at least reduced, at least between the widening section of the preliminary product. Due to the fact that frictional forces between the outer surface of the precursor and the inner surface of the negative mold, against which the precursor is indeed formed avoided or at least reduced, the problems described above no longer or only to such a small extent that unintentional support by the expanded portions of the precursor during axial upsetting no longer occurs. This ensures that the not yet expanded sections of the precursor can still be compressed and thereby are in turn radially expanded, and these sections also unfold no support effect due to the moving negative mold, which counteracts the upsetting process. As a result, then the finished end product, namely the wire shaped body produced by the method according to the invention has a uniform compression over its axial length.

The uniform compression of the shaped wire body is for a variety of reasons of great advantage, since, for example, when using the wire shaped body as a filter for a mass flow, for example, a liquid or gas stream to flow through the wire shaped body, the wire shaped body over its entire length and also over his Cross section has at least approximately constant flow resistance.

Further advantages of the invention will become apparent from the following description, the dependent claims and the drawings.

Thus, in a particularly preferred variant of the method, it is proposed to use a precursor which has an opening extending in the axial direction, preferably a through opening into which a support element, for example a rod with a round or polygonal cross section, is inserted prior to upsetting. With the help of this rod, the precursor is supported during the Stauchefs from the inside, so that in the finished wire molding body inside the outer dimensions of the rod corresponding opening is maintained. The rod can be removed from the wire shaped body again after the upsetting process.

If a precursor is processed which has a comparatively large axial extent, it is proposed to use a negative mold which is formed from two sectionally intermeshing form elements. The mold elements are designed so that during the upsetting process at least one of the mold elements is carried and thereby engages with the other mold element in such a way that the mutually engaging portions of the mold elements form an at least approximately closed support surface, against which during upsetting be formed radially expanding portions of the precursor.

In a variant of the method according to the invention, a cut-off wheel extending transversely to the longitudinal direction is intended to be provided in the finished wire shaped body, which divides a through opening extending through the wire shaped body. For this purpose, it is proposed that in the pre-product already provided through opening the cutting disc is used, which is held pressed by the compression of the precursor and the associated compression and expansion of the precursor both outwardly and inwardly in the finished wire molding.

In order to give the finished wire molded article, if necessary, additional rigidity, it is proposed in a further variant of the method to provide the precursor with an additional Amierungsgestrick, -week or -gewirk, which around or into a first knitted wire mesh fabric or -gewirk manufactured precursor is used. During the forming, the two materials are then pressed together so that the finished end product is integrally formed.

In a particularly preferred variant of the method according to the invention is further proposed to preform an elongated wire initially in the form of a helical helical structure and insert the helically preformed wire in the forming device for forming the precursor and then transform the precursor by means of the forming device to form the wire molding.

Unlike in the prior art usual, this process variant eliminates the production of an intermediate product, which must be prefabricated in a separate manufacturing process prior to the actual forming process of the wire molding. According to the invention, a conventional wire is preformed initially in the form of a helical helical structure, the term "helical helical structure" in the present application being understood to mean a single or multi-start cylindrical spiral or helix. This spirally preformed wire is then inserted directly into the forming device, wherein the preformed wire forms the precursor only in the forming device. After the wire has been cut off, the wire section inserted as a precursor in the shaping device is finally shaped into the shaped wire body with the aid of the shaping device. It should be noted that the wire is either separated during insertion into the forming device, or has already been separated before insertion into the forming device and is inserted as a wire section in the forming device.

During forming, adjacently disposed helical portions of the wire are engaged with each other and plastically deformed with each other so that after forming a defined but permeable to liquids and gases wire structure is maintained.

This variant of the method according to the invention eliminates a large number of upstream manufacturing steps that have hitherto been customary in conventional production methods, such as preparing the wires prior to knitting, weaving or knitting, knitting, weaving or knitting the wires into continuous intermediates and separating individual sections from the continuous intermediates or the unpacking and cleaning of the previously separated from the continuous intermediate hose and mat sections.

Particularly advantageous in the inventive method is the use of a wire with polygonal, preferably rectangular or square cross-section. The very fact that the wire need not be knitted, woven or knitted in the present process makes the use of square-section wires possible.

The use of a wire for the wire molding having a polygonal cross-sectional shape uniform over its length instead of using a wire whose cross-sectional shape is round has various advantages.

Thus, it has been shown that by using a cross-section polygonal wire constantly changes its spatial orientation over the length seen in the wire shaped body due to its previously made spiral pre-deformation, laminar and turbulent flows can be generated in the wire shaped body targeted, which influence the flow behavior targeted. The turbulent flows in turn lead to a significant increase in the flow resistance of the wire molding as compared with wire moldings, which are made of wires with round cross-sectional shapes.

In order to realize the same flow behavior, in particular a virtually identical flow resistance in the wire shaped body according to the invention, the length of necessary wire can be reduced compared to conventional wire shaped bodies of wires with a round cross-section, while still a due to the intrinsically unfavorable flow behavior of the wires with angular cross-section can be maintained approximately constant flow resistance.

The fact that a shorter wire length can be used in the wire molding according to the invention, in turn, leads to a reduction of the weight of the wire molding according to the invention compared to the weight of a conventional wire molding of wires with a round cross section.

If, for example, a wire shaped body is used as a reference, which is made of a round wire with a wire diameter of one millimeter and a length of 1000 mm, one needs for a wire shaped body according to the invention when using for example a cross-sectionally square wire with an edge length of 0 in each case. 89 mm only a length of 678 mm, resulting in a weight saving of approximately 32%. With a cross-sectionally square wire with an edge length of 0.6 mm and a length of 1000 mm results in a weight saving of approximately 55% with approximately the same flow resistance.

When using a cross-section polygonal wire for the production of the shaped wire body, it is possible to save material significantly with constant flow behavior. It is also possible to selectively influence and adjust the flow behavior and the heat transfer behavior by selective selection of the cross-sectional shapes and wire lengths.

Particularly preferred for the inventive method, a wire is used, which has a rectangular or square cross-sectional shape, since these cross-sectional shapes can be made easily by pulling the wire.

So that the wire shaped body retains its external shape after upsetting, in particular when precursors of very fine wires were used for the production, in a further variant of the method, the outer surface of the shaped wire body is partially joined by joining, i. H. by welding or soldering to firmly connect with more inner layers of the wire molding.

According to a further aspect, the invention relates to a forming device for forming an intermediate product made of at least one wire in a wire shaped body, in particular using the method mentioned above. For this purpose, the shaping device has a negative mold, at least one forming punch which can be moved axially to compress the precursor and which cooperates with the negative mold for forming the intermediate product into the wire shaped body, and a housing for the forming punch and the negative mold. According to the invention, the negative mold together with the forming die to the housing is movable such that frictional forces are prevented at least between the portion of the precursor expanding during the axial compression of the precursor and the moving portion of the negative mold, but the frictional forces at least with respect to the axial movement of the Preproduct that undergoes the precursor during compression, are reduced.

In a preferred embodiment, the negative mold has at least one mold element which cooperates with the forming punch during forming together with the forming punch and which is displaceably mounted in the housing and is adjustable together with the forming punch. The mold element can be adjusted either independently of the forming die. In an alternative, particularly preferred embodiment, the mold element is firmly connected to the forming die and is carried along with the forming die. The mold element can be integrally or detachably connected to the forming die. The latter is advantageous if the forming device has to be quickly converted to different shaped wire bodies.

Depending on the wire shaped body to be produced, it is also proposed that the negative mold has two interlocking interlocking mold elements which move axially into one another during upsetting such that the already intermeshing sections of the molded elements form an at least approximately closed support surface which forms during molding the wire shaped body radially expanding portions of the precursor is supported. Preferably, each forming element is associated with a forming die, which cooperates with the respective associated forming element for forming the shaped wire body. Alternatively, however, it is also possible to provide, for example, only one forming die, which is movable together with one of the mold elements, while the other mold element is fixed in a predetermined position. Furthermore, it is also conceivable that both mold elements are movable, while only one forming die is provided, and the precursor is supported on its opposite end of the forming die in the housing.

In a particularly preferred embodiment of the forming device according to the invention, two forming punches are provided, wherein the respective form element projects from the end face of each forming punch. The forming dies are displaceably mounted in the housing along a common longitudinal axis and movable toward or away from one another. The two form elements are provided with complementary cooperating support fingers, which move axially together during the movement of the forming die, that the already engaged sections of the support fingers form an at least approximately closed support surface for the arranged between the Umformstempeln intermediate product. By oppositely acting form elements possibly resulting frictional forces are canceled during Stauchefs against each other, so that a wire shaped body with a considered over its length particularly uniform compression can be made.

According to a second aspect, the invention relates to a from a mass flow, as a liquid stream or a gas stream, to be traversed by wire shaped body of at least one wire having a viewed through its axial length flowed predetermined average flow resistance, based on the predetermined average flow resistance in a Range of a maximum of ± 5%, preferably in a range of not more than ± 2.5% over the axial length varies.

The invention will be explained in more detail below with reference to two exemplary embodiments with reference to the drawing. Hereby shows:

1a C three different operating positions of a first embodiment of a forming device according to the invention in a schematic representation;

2 a diagram in which relative to the axial length of the one in the 1a shown to c forming device shown wire molding the compression of the wire material is shown.

3 a front view of a second embodiment of a forming device according to the invention;

4 a sectional view along the section line AA through the forming device according to 3 in collapsed operating position;

5 a sectional view according to the 4 the forming device immediately before the upsetting process;

6 an enlarged detail view of the in 4 left end shown the forming device with an additionally inserted spacer sleeve;

7 a perspective view of a forming die of the forming of the 3 to 6 ; such as

8th a front view of the forming die 7 ,

In the 1a to c is a schematic representation of a first embodiment of a forming device according to the invention 10 shown in different operating positions.

The forming device 10 has a housing 12 on a base plate 14 rests. In the case 12 is a lower stamp 16 arranged on the base plate 14 is releasably attached. In the case 12 is also a negative form 18 slidably received, in its lower section at the lower punch 16 is guided. At the top of the case 12 is an upper stamp 20 slidably held, by means of an actuator (not shown) between a raised position in which he out of the housing 12 has moved out and a lowered position in the direction of the lower punch 16 is too movable.

At the bottom stamp 16 is also a support element 22 held in the form of a cylindrical rod. The support element 22 sticks out over the negative mold 18 out into one in the upper punch 20 trained receiving opening 24 ,

The negative form 18 is also adjustable by means of an actuator (not shown) and, as will be explained later, together with the upper punch 20 in the longitudinal direction of the housing 12 moved back and forth.

In the 1a to c, the forming process is shown, which will be explained in more detail below. First, the upper punch 20 moved to its raised position, in which of the negative mold 18 closed forming space 26 is open. Subsequently, in this embodiment, a hollow cylindrical precursor 28 in the forming space 26 used, the precursor 28 on the support element 22 is postponed. In the precursor 28 For example, it is a tube section knitted from a wire.

Thereafter, the upper punch 20 until lowered to the front of the precursor 28 comes to rest while simultaneously entering the open end of the negative mold 18 is introduced. This operating position is in 1a shown.

Now the upper stamp 20 together with the negative mold 18 towards the lower punch 16 moved, the precursor 28 is compressed in its axial longitudinal direction. The movement of the negative form 18 is the way to the movement of the stamp 20 adapted that the expanding sections of the precursor 28 , which arise during the upsetting process, with respect to the inner surface of the negative mold 18 no, or possibly experience a slight relative movement. This intermediate position is in 1b shown.

The upper stamp 20 will now go down as far as the precursor 28 is converted into its desired compressed final shape and the finished wire molding 30 is formed as in the in 1c shown end position is recognizable. By the process of the negative mold 18 Any resulting frictional forces between the inner wall of the negative mold 18 and the outer surface of the precursor 28 eliminated.

In 2 is a schematic representation of a diagram in relation to the finished end product, namely the wire molding 30 , the compression over the axial length of the wire molding 30 is recorded. As can be seen from the diagram, the wire molding shows 30 considered over its axial length at least an approximately constant compression.

In the 3 to 8th is a second embodiment of a forming device 40 shown, the forming device 40 has a two-part housing 42 with a continuous axial bore 44 , In the axial bore 44 are two identically formed forming dies 46 slidably taken with reference to the 7 and 8th briefly explained below.

7 shows a perspective view of the forming die 46 , The forming stamp 46 has a cylindrical flange 48 , from the center concentrically a hollow cylindrical punch section 50 projects. To the stamp section 50 are a total of four support fingers 52 evenly distributed (see. 8th ), which firmly with the stamp section 50 are connected and protrude beyond this in the axial direction. The support fingers 52 are identical and designed as segments of a hollow cylinder. Viewed in the circumferential direction (cf. 8th ) are the support fingers 52 so dimensioned that in each case a recess 54 is maintained, with the distance between each two adjacent support fingers 52 is slightly larger than the radians of each support finger 52 ,

The two forming dies 46 are in the axial bore 44 slidably receivable, wherein the forming die 46 are twisted relative to each other so that each of the support fingers 52 of a forming stamp 46 in the recess 54 of the other forming stamp 46 is insertable.

Should now be an intermediate product 56 be transformed, the precursor 56 , which is a tube section knitted from a wire, first onto a support element 58 reared. Subsequently, the support element 58 with the raised precursor 56 in the of the support fingers 52 formed space of one of the forming dies 46 introduced. After that, the forming stamps 46 towards each other, wherein, as previously described, the support fingers 52 of a forming stamp 46 in the recesses 54 of the other forming stamp 46 intervene and vice versa. During the subsequent sequence of movements, the support element 58 from the one forming die 46 so far inside in the hole 44 introduced until that on the support element 58 reared precursor 56 with its two end faces on the front sides of the stamp sections 50 the forming stamp 46 is applied.

Subsequently, the two forming dies 46 further inward driven, the precursor 56 is compressed axially. Due to the fact that on the support fingers 52 the mutually moving forming die 46 act opposing frictional forces opposite, they lift up, so that the precursor 56 experiences a uniform compression over its axial length. When moving together the forming dies 46 become the support fingers 52 moved axially into one another such that the already engaged sections of the support fingers 52 an at least approximately closed support surface for between the Umformstempeln 46 arranged precursor 56 form.

As soon as the forming dies 46 arrived in their end positions, in which they are with their flanges 48 on the two front sides of the housing 42 abutment, is molding of the wire molding 60 completed. Subsequently, the two forming dies 46 moved apart again, the case 42 moved apart and the finished wire molding 60 together with the support element 58 out of the case 42 ejected.

Should a wire shaped body 60 are manufactured, which has a different axial length, is on the support fingers 52 and the stamp section 50 of the forming stamp 46 a spacer sleeve 62 postponed the insertion movement of the forming die 46 limited if the respective spacer sleeve 62 at the front of the housing 42 comes to the plant, as in 6 shown an enlarged detail view of the in 4 shown left end of the forming device 40 ,

LIST OF REFERENCE NUMBERS

10

reshaping

12

casing

14

baseplate

16

lower stamp

18

negative form

20

upper stamp

22

support element

24

receiving opening

26

shaping space

28

precursor

30

Wire moldings

40

reshaping

42

casing

44

drilling

46

forming die

48

flange

50

stamp section

52

support fingers

54

recess

56

precursor

58

support element

60

Wire moldings

62

spacer

Claims (13)

A method for producing a shaped wire body, in which a precursor produced from at least one wire is compressed by a forming device in the axial direction, wherein the precursor is at least partially radially outwardly widened against a negative mold of the forming device so that it gets its final outer shape, characterized in that the negative mold is at least partially carried along during the upsetting so that frictional forces are prevented at least between the widening section of the precursor and the moving section of the negative mold, but the frictional forces at least with respect to the axial movement of the precursor which the precursor undergoes during the upsetting , are reduced. A method according to claim 1, characterized in that the precursor has an opening extending in the axial direction, preferably a through opening, into which a support element is used before upsetting, which supports the precursor during upsetting from the inside. A method according to claim 1 or 2, characterized in that the negative mold is formed from two interlocking interlocking mold elements which move axially during upsetting such that the already engaged sections of the mold elements form an at least approximately closed surface, against which be formed during the upsetting radially expanding portions of the precursor. A method according to claim 1, 2 or 3, characterized in that the intermediate product preferably produced by knitting, weaving or knitting has a through opening extending in the axial longitudinal direction through the precursor, into which prior to upsetting a cutting disc extending transversely to the axial longitudinal direction is used , which is formed by the upsetting of the precursor in the finished wire molding. Method according to one of the preceding claims, characterized in that the precursor is made of a first wire mesh, knitted or knitted fabric of a first wire and a reinforcing knitted fabric or knitted fabric of a relation to the first wire thicker second wire. Method according to one of the preceding claims, characterized in that the precursor is formed, in which at least one elongated wire initially preformed in the form of a helical spiral structure, the spirally preformed wire subsequently inserted into the forming device to form the precursor and the precursor then with the aid of Forming device is formed into the wire molding. Method according to one of the preceding claims, characterized in that the at least one wire has a polygonal, preferably rectangular or square cross-section. Method according to one of the preceding claims, characterized in that portions of the outer surface of the formed wire shaped body are joined together by joining. Forming device for forming a made of at least one wire precursor ( 28 ; 56 ) in a wire shaped body ( 30 ; 60 ), with a negative form ( 18 ), at least one for axial compression of the precursor ( 28 ; 56 ) movable forming punch ( 18 ; 46 ), which with the negative form ( 18 ) for forming the precursor ( 28 ; 56 ) in the wire shaped body ( 30 ; 60 ) and a housing ( 12 ; 42 ) for the forming die ( 18 ; 46 ) and the negative form ( 18 ), characterized in that the negative mold ( 18 ) together with the forming die ( 18 ; 46 ) to the housing ( 12 ; 42 ) is movable such that frictional forces at least between the during the axial compression of the precursor ( 28 ; 56 ) expanding portion of the precursor ( 28 ; 56 ) and the moving portion of the negative mold ( 18 ), the frictional forces at least but with respect to the axial movement of the precursor ( 28 ; 56 ), which is the precursor ( 28 ; 56 ) during compression, are reduced. Forming device according to claim 9, characterized in that the negative mold at least one during the upsetting together with the forming die ( 46 ) for shaping the shaped wire body ( 60 ) cooperating form element ( 52 ), which in the housing ( 42 ) is displaceably mounted and together with the forming die ( 46 ) is adjustable. Forming device according to claim 9 or 10, characterized in that the negative mold (two partially interlocking form elements 52 ), which move into each other during compression such axially that the already engaged sections of the form elements ( 52 ) form an at least approximately closed support surface, which during the molding of the shaped wire body ( 60 ) radially expanding portions of the precursor ( 56 ) supports that each form element ( 52 ) a stamp section ( 50 ) of the forming die ( 46 ) and that the shape elements ( 52 ) and the stamps ( 50 ) for shaping the shaped wire body ( 60 ) interact. Forming device according to claim 11, characterized in that close to the end face of each stamp section ( 50 ) of the forming die ( 46 ) protrudes the respective form element that the Umformstempel ( 46 ) in the housing ( 42 ) are displaceably mounted along a common longitudinal axis and movable towards or away from each other, and that the two form elements with complementary cooperating support fingers ( 52 ) are provided, which when moving together the forming die ( 46 ) axially into one another in such a way that the sections of the supporting fingers ( 52 ) an at least approximately closed support surface for between the Umformstempeln ( 46 ) arranged precursor ( 56 ) form. From a mass flow transversely to flow-through wire shaped body of at least one wire, which has a predetermined average flow resistance considered over its axial length, which in relation to the predetermined average flow resistance in a range of not more than ± 5%, preferably in a range of maximum ± 2, 5% varies over the axial length.

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