EP1497053B1 - Clinching method and tool therefor - Google Patents

Description

State of the art
• The invention relates to a method for a clinching connection of components with at least one plate according to the preamble of claim 1 and of a tool according to the preamble of claim 4, in particular for carrying out the method.
• In a known method of this type ( GB 2069394 A ), the resilient wall portions are formed on four pillars forming the die, which pillars provide radial elasticity therein and gaps are present between the pillars which adversely affect the same by receiving the pinched material and corresponding uncontrollable configuration thereof. According to one embodiment, these gaps are also provided in the bottom of the die, whereby the radial flow is affected when crushing the surface areas. According to another embodiment described therein, the bottom, at least in its central region, is closed and formed as a resilient piston, which in turn has the disadvantage that when displaced radially displaced material can penetrate into the resulting gaps between said columns and these pistons ,

1. a) bei dem ein Stempel odgl. Flächenbereiche dieser Platte in eine Matrizenöffnung des Sockelteils einer Matrize
2. b) zuerst ohne Durchtrennung der Platte tiefzieht und
3. c) danach dieses tiefgezogene Plattenmaterial unter plastischer Verformung desselben zwischen Stempel und Bodenfläche der Matrize quer zur Achsrichtung und entgegen der Kraft elastisch nachgiebiger Wandabschnitte der Matrize verdrängt,
   nicht entnehmbar. Durch den Stanzvorgang und die dort gegebene Gestaltung des Nietschaftes wird ein Tiefziehen und danach quer zur Achsrichtung vorgesehenes Verquetschen des tiefgezogenen Materials verhindert. So kann auch nicht das Verfahrensmerkmal
4. d) zutreffen, dass gemäß der Erfindung "zur Herstellung der Verbindung dieses radial verdrängte Plattenmaterial die entsprechend nicht tiefgezogenen Bereiche der Platte untergreift", sondern der gespreizte Nietschaft untergreift die Platte ohne dabei gemäß Merkmal c) Plattenmaterialien nach dem Tiefziehvorgang (Merkmal b) quer zur Achsrichtung zu verdrängen.

In another known method ( EP 0 720 695 B1 ), a "lost rivet" as a punch rivet is pushed through one of the plates to be joined, after which, due to the design of the rivet, it is spread open. Here, the piercing of the "upper sheet during riveting a far as gentle treatment of the upper plate ...." is sought. This known method is the generic features of the invention, namely a method for a clinching connection of components (plates, bolts, nuts or the like.) With at least one plate,

1. a) in which a stamp or the like. Surface areas of this plate in a die opening of the base part of a die
2. b) first deep-draw without cutting through the plate and
3. c) thereafter displacing this deep-drawn plate material with plastic deformation thereof between the punch and the bottom surface of the die transversely to the axial direction and against the force of elastically yielding wall sections of the die,
   not removable. The stamping process and the design of the rivet shank provided there prevent deep-drawing and then crimping the deep-drawn material provided transversely to the axial direction. So can not the process feature
4. d) apply that according to the invention "for producing the compound of this radially displaced plate material engages the corresponding non-deepened areas of the plate," but the spread rivet shank engages the plate without according to feature c) plate materials after the deep-drawing process (feature b) transversely to Displace axial direction.

According to another known method, or a known device ( EP 0 330 061 ) are two opposite Wall sections designed so that they yield resiliently, wherein the deep-drawn and squeezed surface parts engage behind the plate at the resilient points, however, in the other transverse directions, in which no resilient walls are present, only smooth in the joining direction. Disadvantage of this is that on the one hand during the operation at the given divergence of the opposite wall parts squeezed material can penetrate into the gaps formed thereby and that on the other hand, the non-engaging portions slightly tapered outwards, ie have a tendency to "Unknöpf". The expert was primarily concerned here, on the one hand at least partially obtain the greatest possible Hintergreifung the squeezed surface parts under the stopped sections of the plate and on the other hand to accomplish with as one pass such a connection point and this, of course, with sufficient strength.

At the time of the patent application, the awareness and interest of the clinician in clinching joints was primarily to cleanly separate the deep drawing operation from the squeezing operation to thereby gain control over the operation of the process. In a known device ( DE OS 4435460 ) Therefore, the evading wall parts of the die are not only loaded by a spring against the squish, but it also generates a tilting moment on the lower bearing of these wall parts, creating a clear separation between completion of the thermoforming process and the beginning of the crimping process, without therefore the Crushing itself is directly affected by these movable wall parts.

In yet another known device ( DE OS 198 43 834 A1 ) or another known method ( EP 1183130 B1 ) Although surface areas of a plate deep-drawn and then displaced transversely to the axial direction, which also radially displaced plate material engages the non-deep-drawn areas of the plate, but in a different way, as in the invention. In contrast to the type of the invention, this radial deformation of the deep-drawn plate material is not according to feature c) "against the force of elastically yielding wall portions of the die", but against radially unyielding wall sections which are pivotally mounted on levers to remove the workpiece due to the given undercut to be able to. Apart from the fact that generic essential features are missing in this known device, or this known method, such an undercut with the removal problems of the workpiece, including the resulting additional Bearbeitungsurigszeit and susceptibility, undesirable.

Last but not least, a device for a clinching method is known, in which the four wall parts of the die are pressed radially outward against a ring spring during the deep-drawing or squeezing operation ( EP 0 653 255 A1 ). To the die a metal cage is arranged, which, however, only has the task of receiving the Matrizenteile and lead. Any influence on the thermoforming or squeezing process does not have this cage. Another disadvantage is that the matrix bottom forms the end face of a piston which projects into the die and that the die wall parts are guided on a step thereof for the crimping process. It is also required considered that on the front side of this piston a known survey is present, which of course has influence on the crushing process. When inserting this tool also has the disadvantage that the lateral forces on the upper ends of the wall parts of the die attack and thus produce a tilting moment, which can cause the arranged in the cage guide pins tilt. In addition, there is the disadvantage that squeezed material passes into the region between the wall parts and this piston, so that the actual squeezing process with respect to the material deformation of the plate sections is largely uncontrollable, with the survey on the piston head rather disadvantageous effect. Obviously, the result sought with this tool is to achieve a high degree of ambush, on all sides of the connection point.

The problem underlying the invention

The invention has for its object to achieve in generic methods and devices for clinching an improvement in the strength of the joint point on the cold deformation of the squeezed material without getting chips or squeezed materials in tool columns and lead to an impairment of production, this also with should be possible to achieve the simplest possible means.

The invention and its advantages

The method according to the invention with the features of claim 1 and the tool according to the invention with the features of claim 4, in particular for carrying out the method, has the advantage that a controlled, clean thermoforming process takes place in order to achieve a targeted radial squeezing without squeezing Material undesirably gets into any gaps and wherein the unyielding limitation of the path of the resilient wall sections cold deformation of the squeezed material takes place, which has a strength increase of the joining point by about 30% compared to a non-cold-formed crushed material result. In this way it is also achieved that these materials engaging behind the plate are particularly firm due to the respective stop. In addition to these advantages, such a connection point can be accomplished in only one operation, despite Hintergreifung by appropriate management of the flow of the displaced material, ie the workpiece can be removed without an additional operation of the tool of the machine tool.
By the remaining wall sections advantageously displace the crushed material in the direction of the displaceable wall sections, it is also of particular importance that the resilient wall sections are displaceable on a surface which is parallel to the direction of displacement and continuously merges into the bottom surface of the die. As a result, it is above all also avoided that an accumulation of displaced material of the deep-drawn and pinched plate sections takes place there.

In any case, by leaving standing firmly connected to the base part of the die parts of the wall portions a greater Hintergreifung the stopped surface portions of the plate is achieved.

According to an advantageous embodiment of the inventive method, the limitation of the radial path, seen over the circumference of the die, different, changeable or alternately large, so that thereby different hardnesses in the cold deformation can be achieved.

According to an additional embodiment of the invention relating to the method, the stamp remains, at least as far as it dives into the die opening, formed as a lost stamp, rivet-like and positively in the penetration. As a result, on the one hand a quasi insolubility of this push-button-like connection point is achieved and on the other hand, the possibility of additional Verbindtingsteile such as nuts, bolts or the like. to connect with the plate by the lost stamp is formed either in the form of these connecting parts or as a counterpart to it.
The particular advantage of the generic tool ( WO 02/081112 A2 ) is that, seen on the circumference of the work opening, between the movable wall sections unyielding, in particular integrally formed with the base part wall sections so form a good and easy to control leadership of the resilient wall sections. The radially squeezed material is thereby increasingly displaced into the areas of the resilient wall sections. But only by the inventive, the radial path limiting stop according to claim 4 is the following Pressing due to these attacks a correspondingly high compression and thus hardness of the engaging behind surface parts achieved.

After additional tool-related embodiments of the invention, the stop, which limits the path of the radially resilient wall sections, for example, in one piece on the base part of the die arranged. As a result, the corresponding strength is achieved in a simple manner. However, according to the invention, this stop can also be adjustable or adjustable. Normally, however, the die is exchanged when the radial path is changed, for example, in another insert. But also a change in the position of the attack can be achieved with little effort. The decisive factor is that this adjustment or adjustment ensures that there is a firm connection between the stop and the base part.
In any case, according to the invention, the base part can consist of one piece, in which grooves and bores for receiving the resilient wall sections of the springs are udgl. are arranged. This creates a compact, easy to use in the machine tool.

Advantageously, the known to the work opening facing bottom surface of the base part serves as a support and for radial guidance of the wall sections. In this way it is especially avoided that during the operation and corresponding displacement of the wall sections gaps in the ground arise, in which material of the displaced plate sections could penetrate, whereby the inventively achieved Kaltverhärtung could be questioned and also several operations would be required to make the connection point.

According to an additional advantageous embodiment of the tool of the stamp in a conventional manner ( EP 0 720 695 B1 ) as a lost stamp in the form of a rivet, a nut, a bolt or the like. formed and remains after completion of the clinching positively and / or non-positively in the effected by him deep draw opening of the plate. Through this composite material, an additional strength of the compound is created primarily by the fact that the deep-drawn opening is filled in a form-fitting manner and a disconnection of the connection point is no longer possible. In the known lost stamp ( EP 0 720 695 B However, it is a semi-tubular rivet with which a sheet is pierced to connect two sheets, after which an artificial spreading of the semi-tubular rivet with Hintergreiffunktion takes place. In contrast, in the invention, the lost stamp is processed in such a way that first both sheets are deep-drawn without cutting to then displace the thermoformed material radially under plastic deformation. The use of a Halbhohlnietes would not be possible according to the invention.
According to an additional advantageous embodiment of the invention, an annular groove for receiving the displaced material is present in the radial lateral surface of the punch, thereby improving the anchoring of this lost punch in the plate or in the deep-drawn opening.

According to an additional advantageous embodiment of the invention, the stamp on the bottom surface facing the end face on a survey. Through this survey takes place, for example when used in a rivet, a better spreading of the front side and thus a better undercut of the joint point.

According to an additional advantageous embodiment of the invention, a frontally open annular channel is arranged in the bottom surface of the base part. By such an annular channel, the front end of the lost punch, especially if it is designed as a rivet, spread better, since the material to be displaced finds a corresponding receptacle.

According to an additional advantageous embodiment of the invention is on the bottom surface of the base part in a conventional manner ( EP 0 720 695 B1 ) has a centrally symmetric elevation. This survey does not exclude that, for example centrally symmetrical to her in the bottom surface an annular channel is arranged. Such a survey forces the stamp material to spread open, this spreading usually takes place after the deep-drawing process.

drawing

Embodiments of the subject invention are illustrated with workpiece variants in the drawing and will be described in more detail below.

Fig. 1

ein erfindungsgemäßes Werkzeug vereinfacht und im Teillängsschnitt dargestellt, entsprechend der Schnittlinie I-I in Fig. 2;

Fig. 2

eine Draufsicht auf die Matrize gemäß dem Pfeil II in Fig. 1;

Fig. 3

eine perspektivische Ansicht auf eine Variante des Sockelteils der Matrize;

Fig. 4

eine Ansicht eines mit diesem Werkzeug hergestellten Verbindungspunktes;

Fig. 5

eine perspektivische Ansicht eines Sockelteils entsprechend Fig. 3 mit einer Erhebung auf der Bodenfläche;

Fig. 6

eine Variante des Stempels [in Seitenansicht] mit einer gewölbten Stirnfläche;

Fig. 7

ein "verlorener Stempel" in perspektivischer Ansicht mit eingesenkten Stirnseiten und

Fig. 8

ein Teilschnitt durch ein Werkstück mit "verlorenem Stempel".

Show it:

Fig. 1

an inventive tool simplified and shown in partial longitudinal section, corresponding to the section line II in Fig. 2 ;

Fig. 2

a plan view of the die according to the arrow II in Fig. 1 ;

Fig. 3

a perspective view of a variant of the base part of the die;

Fig. 4

a view of a connection point produced with this tool;

Fig. 5

a perspective view of a base part accordingly Fig. 3 with a survey on the floor surface;

Fig. 6

a variant of the stamp [in side view] with a curved end face;

Fig. 7

a "lost stamp" in perspective view with sunken end faces and

Fig. 8

a partial section through a workpiece with "lost stamp".

Description of the embodiment

In Fig. 1 and 2 is an embodiment of a tool according to the invention shown without the known per se in a variety of ways machine tool for the clinching of sheets or the connection of bolts, nuts or the like. with a plate, wherein in particular no punching of the plate takes place, but a deep drawing with subsequent crimping of the thermoformed material.

This tool is, on the one hand, a punch 1 driven by the machine tool, which is arranged above two metal plates 2 and 3 to be connected to one another and opposite a working opening 4 of a multi-part die 5. Stamp 1 and die 5 are used for their work in the machine tool, wherein for performing the clinching connection of the punch 1 is actuated after inserting the metal plates 2 and 3, in the direction of the double arrow V. In the downward working stroke, the metal plates 2 and 3 are first deep-drawn in the work opening 4 and then squeezed radially increasing outward after increasing the driving force of the punch 1 on the bottom surface 9 of the work opening 4, wherein the displaced material of the first deep-drawn by the punch 1 and then squeezed surface portions of the metal plates 2 and 3, the remaining portions of the metal plates 2 and 3 engage behind in a known manner and thereby cause the connection of the plates.

Instead of the illustrated method, in which the stamp 1 is pulled out after the connection of the plates 2 and 3 from the work opening 4 according to the arrow V again, according to the invention, the stamp as a lost stamp be formed, ie it is, as not shown in detail, the plates 2 and 3, as well as the work opening 4 upstream and then pressed by a ram for the deep drawing process in the plates 2 and 3. Such a lost punch is either designed as a rivet, which serves mainly to achieve a Ausknöpfen the deep-drawn and pinched plate portions or he can be designed as a threaded bolt, or appropriately trained nut, which then serve, for example, to attach other parts to a plate , Decisive for the invention, as this stamp (Tiefziehquetschstempel as a lost stamp in the form of rivet, bolt, nut or the like.) Deep draws in the first operation, the plate material to then squeeze it in the radial direction.

The working opening 4 of the die 5 is bounded radially by four fixed wall sections 7 and four resilient wall sections 8 and a bottom surface 9, on which the wall sections 8 between the wall sections 7 are radially displaceable. The wall sections 8 have for this purpose a height corresponding to the depth of the working opening 4. The wall sections 8 are loaded by leaf springs 10 in the direction of the working opening 4. The way this wall sections 8 is limited by stops 11 according to the invention.

This basic principle of punch and die can be designed in a variety of ways, with stops 11 are crucial to the inventive function. After the deep-drawing operation of the metal plates 2 and 3 during the first stroke of the punch 1 in the working opening 4, the plate sections of these metal plates 2 and 3, which are deep-drawn over the first upper edge of the working opening 4, undergo a corresponding dilution or a cup-like nesting. During the subsequent second stroke of the punch 1 material is displaced radially outwardly from the resting on the base part 6 deep-drawn plate portions, wherein the displaced material can flow only where the radially movable wall portions 8 are present. These are then displaced against the force of the leaf springs 10, which however do not exert any forming forces on the displaced material, until these wall sections 8 encounter the stops 11. Since the displacement and squeezing operation is not yet completed, then the squeezed material, after after the continued displacement considerable increase in the pressing force, more compacted, resulting in a cold hardening of this displaced material of the plate sections and thus to an increase in the strength of over 30% over such only radially transversely displaced materials. Since these displaced sections, the metal plates 2 and 3 engage behind considerably, which is promoted in particular by the flexibility of the wall sections 8, here creates a connection point with extremely high strength. After retraction of the punch 1, or of the press ram and removal of the workpiece, the wall sections 8 are pushed back by the leaf springs 10 in the initial position shown, so that a new operation can begin. The fact that the wall sections 8 are displaceable on the side facing away from the stamp 1 on the flat bottom surface 9 of the base part 6, high lifting forces can be easily absorbed by the wall sections 8, without detriment to the radial displacement. So that the wall sections 8 receive a corresponding radial guidance, they have wall surfaces 18 parallel to the fixed wall sections 7.

How special 3 and 4 Removable, 9 designs can be made as needed in the not traversed by the wall sections 8 bottom portions of the bottom surface, which can lead to an improvement of the material flow or compression. As exemplified in Fig. 3 shown, in the bottom surface 9 of the base part 6, an annular channel 20 is provided which causes a better spreading of the deep-drawn and pinched plate material, ie the displaced material can escape better. The advantage that results from such an engagement on the workpiece is Fig. 4 can be removed, in which reference to a section of the workpiece, a connection point is shown from the die side, with a the annular channel 20 (FIG. Fig. 3 ) to be assigned to the die annular bead 21 and the squeezed material collections 22, which have due to the facing sides of the movable wall sections, in contrast to the annular bead 21, straight boundary edges 23.

As Fig. 5 can be removed, a central region 24 of the bottom surface 9 may be curved in the stroke direction, for example, to achieve an additional radial squeezing of the displaced plate sections. Around this central area 24 around an annular channel may be present, as it is in Fig. 3 is shown.

In Fig. 6 a variant of the stamp 1 is shown in side view, in which on the front side a survey 13 is arranged, is displaced by the plate material during squeezing radially outward, of course, this leads to a dilution of the bottom of the connection point. Again, we promoted a spreading of the material during the squeezing process.

In the FIGS. 7 and 8 the use of "lost stamps" is shown, which are processed as described above after insertion into the tool by means of a tool-bound press ram. By such a "lost stamp" especially a buttoned out the connection point is prevented.

In Fig. 7 is designed as a rivet 14 trained "lost stamp", in which both end faces 15 are drawn funnel-shaped inward. By this funnel-shaped training flows, in particular during the squeezing process, the material apart, which is particularly improved the gripping behind of the stopped material by this deep-drawn and crushed material. The hardening according to the invention due to additional compressive forces underpins this effect.

In Fig. 8 is shown in section how such a lost punch 16 is embedded in the plates 2 and 3 after the pressing and deep-drawing process. The caused by the rivet 16 pot 17 in the plates 2 and 3 has a taper in the middle, which forms an extremely strong bond between the plates 2 and 3 by the stored lost punch 16. In addition, the free end of this lost punch 16 lies in the plane of the outer surface of the plate. 2

LIST OF REFERENCE NUMBERS

1

stamp

2

metal plate

3

metal plate

4

work opening

5

die

6

base part

7

fixed wall sections

8th

sliding wall sections

9

floor area

10

leaf spring

11

attack

12

Front side of 1

13

survey

14

rivet

15

Front side of 14

16

lost stamp

17

rejuvenation

18

Wall surfaces of 8

20th

annular channel

21

torus

22

material collection

23

boundary edge

24

central area

Claims (10)

1. Method for a clinching connection of components, for example plates (3), bolts, nuts or similar, having at least one plate (2),

   a) in which a punch (1) or similar

   b) - firstly deep-draws flat regions of said plate (2, 3) into a die opening (4) of the base part (6) of a die (5) without cutting through the plate, and

   c) - thereafter forces this deep-drawn plate material, under a process of plastic deformation of the same, between the punch (1) and base surface (9) of the die transversely to the axial direction (III) and against the force of elastically flexible wall sections (8) of the die (4),

   d) - wherein to create the connection, said radially forced plate material engages the non-deep-drawn regions of the plate (2) from below,
   characterized in that

   e) - wall sections (7) that are rigidly connected to the base part (6) of the die (5) are present between the flexible wall sections (8) of the die opening (4),

   f) - the flexible wall sections (8) can be displaced on a surface which is aligned parallel to the displacement direction and merges into the base surface (9) in an uninterrupted manner and

   g) - in order to obtain a compression, and hence a hardening, of the displaced and thus squeezed material, the radial path of the flexible wall sections (8) is rigidly limited (11) after a pre-defined distance has been covered.
2. Method according to Claim 1,
   characterized in that
   the limiting of the radial path, viewed over the circumference of the die (5), can be varied by different amounts or varies in size, in such a way that different hardness values can be obtained during the cold forming process.
3. Method according to Claim 1 or 2,
   characterized in that
   the punch (1), at least as far as it penetrates into the die opening (4), is constructed in the form of a hidden punch (16) and remains in the manner of a rivet and with a positive-fit in the penetration opening.
4. Tool with punch (1) and die (5), for making a clinching connection of components, for example plates (3), bolts, nuts or similar, having at least one plate (2) and without cutting through the plate,

   - having a working opening (4) arranged on a base part in the multi-part die (5),

   - having multiple wall sections (8) of the die (5) arranged radially around the working opening (4) that are guided outwards in a flexible manner during the jointing process,

   - having a base surface (9) of the die (5), arranged opposite to the front face of the punch (1) and axially bounding the working opening (4), and

   - having multiple wall sections (7) between the flexible wall sections (8), distributed over the circumference of the working opening (4), some of which are inflexibly connected to the base part (6) and some of which, serving to radially guide the flexible surrounding parts (8), are rigidly connected to the base part (6),

   - in particular for also carrying out the method according to any one of Claims 1 to 3,

   characterized in that

   - the radial path of the wall sections (8) during the jointing process of the die (5) is limited by a an inflexibly arranged stop (11) and

   - that said stop (11) is rigidly attached to the base part (6) of the die (5).
5. Tool according to Claim 4,
   characterized in that
   the punch (16) is a hidden punch in the form of a rivet, a nut, a bolt or similar, in order to remain in the deep-drawn opening of the plate (2) formed by said punch in a positive-fitting or force-fitting manner after the completion of the clinching joint.
6. Tool according to Claim 5,
   characterized in that
   the hidden punch has the form of a rivet (14) and at least prior to the processing has an indentation (15) on both faces thereof.
7. Tool according to Claim 5 or 6,
   characterized in that
   an annular groove is present in the radial outer surface of the lost punch (16) for retaining the squeezed material.
8. Tool according to one of Claims 4 to 7,
   characterized in that
   an elevation is arranged on the front face (12) of the punch facing the base surface (9).
9. Tool according to one of Claims 4 to 8,
   characterized in that
   an annular channel (20), open on the front face, is arranged in the base surface (9) of the base part.
10. Tool according to one of Claims 4 to 9,
    characterized in that
    a centrally-symmetrical elevation (24) is present on the base surface (9) of the base part.

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