DE102011110598A1 - Method and tool for producing a full punch rivet - Google Patents

Abstract

The invention relates to a method for producing a rivet rivet in which a cut wire piece (8) is deformed via a tool (1) comprising a punch (4) and a die (2), wherein the wire piece (8) is arranged between bake-like, radially adjustable moldings (33), which form the Nietumfangskontur (321) and at least one annular groove forming an undercut (322) is clamped, and subsequently the wire piece (7) at its two ends via a respective pressure pin (24, 46) an axial force is applied, whereby the wire material fluently fills the Nietumfangskontur formed by the fittings (33). The invention further relates to a tool for producing a full punch rivet by means of a method according to one of the preceding claims, comprising a die (2) and a punch (4) which can be moved axially in the direction of the die (2), wherein the die (2) is formed by a frame element (31) having a conical feedthrough (31), in which at least three shaped pieces (33) are guided so as to be radially adjustable, defining a rivet peripheral contour (321) and having at least one annular groove (322) forming an undercut, wherein the Fittings (33) via spring elements (44) in the direction of the largest cone diameter of the frame member (31) are biased.

Description

The invention relates to a method for producing a full punch rivet according to claim 1. The invention further relates to a tool for producing a full punch rivet according to claim 7.

Punched rivets are used to join flat workpieces, especially sheet metal. The punch rivet is pressed with the simultaneous formation of two punched holes with its shaft through the workpieces. Near its shank end, the shank has at least one shank groove in which the material of the lower workpiece seen in the punching direction is pressed during the punching process.

Such punch rivets are set in particular in the automotive sector via automated Nietsetz devices (so-called rivet eyes) through the workpieces, such as in the DE 10 2004 011 846 A1 disclosed. In order to be able to ensure the required small dimensional tolerances, such punch rivets are manufactured in the prior art by machining processes, in particular by means of turning. However, these methods prove to be very costly, which is partly due to the increased loss of material. In the DE 20 2009 017 846 U1 Therefore, it is proposed to produce a stamped embossment using at least one pressing operation in cold forming. For this purpose, it is proposed to first produce a rivet blank using a press and subsequently to introduce in a second method step by a rolling or rolling process, in particular with a flat jaw or round jaw rolling machine, the at least one shank groove necessary for the riveting process. However, a reworking of the method only slightly described has revealed that this is not only designed to be very expensive and costly. In addition, the consistent dimensional stability required for an automated processing process could not be achieved. Furthermore, in the DE 10 2011 009 649 A1 mentions the production of a punch rivet by means of forming.

The invention aims to remedy this situation. The invention is based on the object to provide a method for producing a Vollstanzniet, which allows a cost-effective production of a full punch rivet at a consistently high dimensional accuracy. According to the invention, this object is solved by the features of claim 1.

With the invention, a method for producing a solid rivet is created, which allows the cost-effective production of a full punch rivet while maintaining high dimensional accuracy. Due to the clamping of the piece of wire between the cheek-like, radially adjustable moldings, which depict the Nietumfangskontur and the subsequent application of the wire piece at its two ends via a respective pressure pin with an axial force, the wire material is temporarily placed in a pseudo-liquid state, whereby the material in the The peripheral contour formed by the fittings flows and fills them. It has been shown that in this way a high dimensional stability is achieved.

In a further development of the invention, the wire piece is pre-compressed prior to clamping in the die by means of a second tool, comprising a second die and a second punch. As a result, a Vorkonturierung the piece of wire is achieved.

In a further embodiment of the invention, the pre-upset wire piece in the second die of the second tool is further advanced by means of the first punch, wherein at one end of the wire piece, a radially projecting head is formed. As a result, an exact axial positioning of the preformed piece of wire between the baking-like shaped pieces of the die of the first tool is possible. In this case, the geometry of the head underside preferably corresponds to the geometry of the rivet head-side outlet of the rivet peripheral contour formed by the shaped pieces.

In a further development of the invention, the further compressed wire piece between the radially engageable fittings of the die is positioned before it is clamped between the fittings, wherein the molded head rests axially on the fittings. As a result, a constant axial positioning of the wire pieces is achieved, whereby a constant dimensional accuracy of the finished solid punch rivet is ensured.

In a further embodiment of the invention, the radially engageable fittings are conically guided axially and the fittings are moved axially by the first punch, whereby the piece of wire is clamped between the fittings. This achieves an integrated clamping and forming process.

The present invention is further based on the object to provide a tool for producing a full punch rivet by means of the aforementioned method, so that a cost-effective production of a full punch rivet is made possible with constant dimensional accuracy. According to the invention, this object is achieved by a tool having the features of patent claim 7.

With the invention, a tool for producing a full punch rivet by means of the aforementioned method is provided, which allows a cost-effective production of a full punch rivet with constant dimensional accuracy. The peripheral shape of the tool is formed by at least three fittings, which are guided radially adjustable and together form the peripheral shape. The at least one undercut forming an annular groove causes a circumferential ridge of the solid punch rivet produced. This circumferential ridge in turn, together with the rivet foot, defines a circumferential groove into which the material of the sheet to be joined, which is plastically deformed during the punching process, penetrates. Due to the bias of the fittings on spring elements in the direction of the largest cone diameter of the frame member, the fittings are spaced apart in the unloaded state, such that a simple positioning of the piece of wire to be deformed is possible. When the shaped pieces are subjected to an axial force, they are moved axially in the direction of the smallest cone diameter of the frame element, as a result of which the shaped pieces are set radially against the wire piece via the conical shape of the leadthrough. As a result, a clamping of the piece of wire between the fittings is achieved.

In a development of the invention, the frame element has at least three holes which open radially into the conical feedthrough and in which pins for axial guidance of the shaped pieces are introduced. As a result, an axially guided movement of the fittings is effected with axial application of force.

In a further embodiment of the invention, the fittings have lateral bores for receiving guide pins, via which the fittings are connected to each other. As a result, a guided radial adjustment of the fittings is effected on the wire piece.

In a further embodiment of the invention, the punch on an outer axially displaceable punch member which is coaxially penetrated by an inner axially displaceable pressure pin, wherein the outer punch member has a conical shoulder, which corresponds to the conical passage at its enlarged diameter end. In this way, a two-stage Anstellprozess allows, initially the outer punch member causes axial movement of the mold pieces of the die, whereby a clamping of the piece of wire is achieved. Subsequently, a force is applied to the piece of wire via the inner pressure pin. Preferably, the outer punch member is biased in the punch via a spring. As a result, a gentle, spring-loaded hiring of the outer punch part is made possible on the fittings.

In a development of the invention, the inner pressure pin can be positioned relative to the outer punch part in such a way that the two punch parts delimit a receptacle for the head of a pre-compressed rivet. As a result, a gripper function is effected, which allows a transport of a pre-compressed rivet from a pre-upsetting die in the die of the tool.

Other developments and refinements of the invention are specified in the remaining subclaims. An embodiment of the invention is illustrated in the drawing and will be described in detail below. Show it:

• a) Matrize mit vier Formstücken;
• b) Stempel (Position „ausgefedert”);
• c) Stempel (Position „eingefedert”)

1 the schematic representation of a tool for producing a solid rivet in cross section:

• a) template with four fittings;
• b) punch (position "rebounded");
• c) stamp (position "compressed")

• a) im Querschnitt;
• b) in der Draufsicht mit eingesetzten Formstücken;
• c) im Schnitt A-A der Figur a);

2 the schematic representation of the fitting insert of the die 1

• a) in cross-section;
• b) in plan view with inserted fittings;
• c) in section AA of Figure a);

• a) in der Draufsicht;
• b) im Schnitt A-A der Figur a);
• c) im Schnitt B-B der Figur b);
• d) im Schnitt C-C der Figur c)
• e) in räumlicher Einzeldarstellung;

3 the schematic representation of the fittings of the die 1

• a) in plan view;
• b) in section AA of Figure a);
• c) in section BB of Figure b);
• d) in section CC of FIG.
• e) in a single spatial representation;

• a) Matrize;
• b) Stempel (Position „Drahtabschnitt einsetzen”);
• c) Stempel (Position „Vorstauchen”);

4 the schematic representation of an upsetting tool in cross section:

• a) template;
• b) punch (position "insert wire section");
• c) stamp (position "pre-dipping");

• a) vor der Verformung;
• b) nach erstem Vorstauchen;
• c) nach zweitem Vorstauchen;
• d) nach Fertigstauchen.

5 the schematic representation of a deflected piece of wire

• a) before deformation;
• b) after first screening;
• (c) after second screening;
• d) after finishing.

The chosen as an embodiment tool 1 for producing a full punch rivet is essentially formed by a die 2 using a fitting insert 3 picks up, and a stamp 4 ,

The matrix 2 consists essentially of a version 21 using a fitting insert 3 receives. The fitting insert 3 is located on an intermediate socket 22 in which a pressure pin 23 is arranged. The pressure pin 23 is from two pushpin receptacles 231 held, between which one coil spring 25 is arranged. The pressure pin 23 lies on a pressure piece 24 on that with an ejector pin 29 in connection and on a clamping screw 27 for adjusting the spring tension of the plate spring package 26 is applied. The clamping screw 27 is in turn at a backcountry 28 on, through which the ejector pin 29 who also used the clamping screw 27 penetrates, is guided. The intermediate socket 22 has a substantially T-shaped cross-section and is over a plate spring 6 against the fitting insert 3 biased at the rear camp 28 is applied.

The fitting insert 3 is formed by a substantially cylindrical retaining ring 31 that with an axial, tapered passage 311 is provided. Surrounding each offset by 90 degrees to each other in the retaining ring 31 four holes 312 introduced, which in the implementation 311 lead.

In the conical execution 311 is a rivet shape 32 used, consisting of four shaped pieces 33 is formed. The rivet shape 32 limits a rivet peripheral contour 321 , which is an undercut forming an annular groove 322 having. Furthermore, the Nietumfangskontur includes 321 the contour of the rivet head 323 as well as the rivet foot 324 , Outside are in the shell of the rivet form 23 each offset by 90 degrees to each other four keyways 325 brought in. In the middle of the keyways 325 is in each case the parting plane of each two adjoining shaped pieces 33 , The fittings 23 are each at their dividing surfaces with a hole 331 for receiving a guide pin 35 Mistake. The rivet shape 32 is in execution 311 of the retaining ring 31 over locking pins 34 axially guided, which in the keyways 325 intervention.

The Stamp 4 consists essentially of a cup-shaped socket 41 that of a use 42 is permeated, being the use 42 a circumferential edge 420 having, at the bottom edge 410 the version 41 is applied. To the use 42 closes an intermediate socket 43 on, which is a push pin 46 which takes in an axial through the insert 42 introduced bore 422 empties. The pressure pin 46 is about a push pin receptacle 461 in the intermediate socket 43 held, taking between the pressure pin recording 461 and the mission 42 the pressure pin 46 surrounding a coil spring 47 is arranged, over which the use 42 against the text 41 is biased. The pressure pin 46 lies on a pressure piece 48 which, in turn, in a clamping screw 45 empties. Between the clamping screw 45 and a T-shaped cross-section intermediate sleeve 43 is a disc spring package 44 arranged over which the intermediate socket 43 against the use 42 is biased. The preload is over the clamping screw 45 adjustable, which in turn on the back 39 is applied.

For producing a full punch rivet, an expanding tool is also used in the exemplary embodiment, as is shown in FIG 4 is shown schematically. The pre-upsetting tool 5 is formed of a second die 6 and a second stamp 7 ,

The second template 6 consists essentially of a version 61 which form a core 62 that picks up from a sleeve 63 is surrounded. mold core 62 and sleeve 63 lie on a support core 64 on, which is a pressure piece 66 receives, on which an ejector pin 65 rests in the mold core 62 empties. The mold core 62 has the shape contour 621 of the piece of wire to be pre-nipped 8th on.

supporting core 64 and pressure piece 66 lie on the back 67 which of an ejector pin 68 is penetrated, on the pressure piece 66 is applied. At his the pressure piece 66 opposite end is the ejector pin 68 in a recording 69 held.

The second stamp 7 of the pre-upsetting tool 5 consists essentially of a pre-sampler 71 , which is a pressure piece 73 receives, on which a pressure pin 72 rests, which from the pre-diver 71 protrudes. The pressure piece 73 is over a coil spring 74 against the prowler 71 harnessed, along with the prowler on a back 75 is applied.

To produce a full punch rivet, a piece of wire is first used 8th cut to length, which into the second matrix 6 of the pre-upsetting tool 5 is inserted so that it is on the ejector pin 68 in the mold core 62 is applied. Subsequently, the second stamp 7 with the preamp 51 on the second die 6 placed, with the pressure pin 72 on the piece of wire 8th rests. Then the piece of wire becomes 8th over the pressure pin 52 subjected to such an axial force that this in the shape contour 621 of the mold core 62 is pre-compressed. The shape of the pre-bent piece of wire 81 is in 5b) shown.

The second stamp 7 is now from the second template 6 of the pre-upsetting tool 5 removed and the stamp 4 of the tool 1 is on the second die 6 of the pre-upsetting tool 5 positioned so that the pressure pin 46 of the stamp 4 on the preformed rivet 81 rests. The following is about the pressure pin 46 an axial force on the pre-compressed rivet 81 applied, the rivet head 831 is preformed. The shape of the thus pre-compressed piece of wire 82 is in 5c) shown. The so pre-bent piece of wire 82 will now over the ejector pin 68 with his rivet head 831 into the hole 422 of the insert 42 of the stamp 4 pressed, the pressure pin 46 inside the stamp 4 is moved back. The pre-bent piece of wire 82 is now in through the hole 422 of the insert 42 and the pressure pin 46 formed recording.

The pre-bent piece of wire 82 is subsequently using the stamp 4 between the fittings 33 the rivet shape 32 positioned. This is the conical paragraph 421 of the insert 42 on the fittings 23 and pushes against the spring force of the coil spring 25 along the conical bushing 311 in the direction of the intermediate socket 22 the matrix 2 , whereby the shaped pieces 33 radially to the pre-compressed piece of wire 82 be created. In this way, the pre-compressed piece of wire 82 between the fittings 33 clamped, with the preformed rivet head 831 on the fittings 33 rests. The geometry of the underside of the preformed rivet head 831 corresponds to the geometry of the rivet head side outlet of the through the fittings 33 Nietumfangskontur formed 321 and lies on top of this.

Below is by the pressure pin 46 of the stamp 4 as well as through the other end of the pre-bent piece of wire 82 adjacent pressure pin 23 a continuous force on the pre-bent piece of wire 82 applied until its material begins to flow and the Nietumfangskontur 321 the rivet shape 32 fills. The completed solid punch rivet 83 now has the in 5d) the reproduced form. Through the into the ring groove 322 the rivet shape 32 Flowed material is here a circumferential bridge 834 trained, which together with the rivet foot 833 a circumferential groove 835 limited.

The Stamp 4 is now from the matrix 2 removed, with the fittings 33 by the restoring force of the coil spring 25 over the pressure pin holder 231 along the conical bushing 311 of the retaining ring 31 to be moved upwards. As a result, the fittings 33 moved apart, causing the completed solid punch rivet 83 is released. The released solid punch rivet 83 will now over the pressure pin 23 from the matrix 2 ejected.

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 102004011846 A1 [0003]
• DE 202009017846 U1 [0003]
• DE 102011009649 A1 [0003]

Claims (13)

Method for producing a full-rivet, in which a cut-to-length piece of wire ( 8th ) via a tool ( 1 ), comprising a stamp ( 4 ) and a die ( 2 ), with the piece of wire ( 8th ) between bake-like, radially adjustable moldings ( 33 ), which the Nietumfangskontur ( 321 ) and at least one annular groove forming an undercut ( 322 ), is clamped, and subsequently the piece of wire ( 7 ) at its two ends via a respective pressure pin ( 24 . 46 ) are applied with an axial force, whereby the wire material flowing through the fittings ( 33 ) formed Nietumfangskontur fills. Method according to claim 1, characterized in that the piece of wire ( 8th ) before clamping in the die ( 2 ) by means of a second tool ( 5 ) comprising a second template ( 6 ) and a second stamp ( 7 ), is pried. A method according to claim 2, characterized in that the pre-compressed piece of wire ( 81 ) in the second die ( 6 ) by means of the first stamp ( 4 ), wherein at one end of the piece of wire ( 8th ) a radially projecting head ( 831 ) is formed. A method according to claim 3, characterized in that the weitergestauchte piece of wire ( 82 ) between the radially engageable fittings ( 33 ) of the die ( 2 ) before it is inserted between the fittings ( 33 ) is clamped, wherein the molded-on head ( 831 ) axially on the fittings ( 33 ) rests. Method according to one of the preceding claims, characterized in that the radially engageable shaped pieces ( 33 ) are guided conically axially and that the fittings ( 33 ) by the first stamp ( 4 ) are moved axially, whereby the piece of wire ( 8th ) between the fittings ( 33 ) is clamped. Method according to one of the preceding claims, characterized in that the deformation of the piece of wire ( 8th ) takes place as cold forming. Tool for the production of a full punch rivet by means of a method according to one of the preceding claims, comprising a die ( 2 ) and a stamp ( 4 ) which extends axially in the direction of the die ( 2 ) is movable, wherein the die ( 2 ) by a conical implementation ( 311 ) frame element ( 31 ) is formed, in the at least three fittings ( 33 ) are performed radially adjustable, which has a Nietumfangskontur ( 321 ) and at least one annular groove forming an undercut ( 322 ), wherein the shaped pieces ( 33 ) via spring elements ( 44 ) in the direction of the largest cone diameter of the frame element ( 31 ) are biased. Tool according to claim 7, characterized in that the frame element ( 31 ) at least three radial, in the conical implementation ( 311 ) drilling holes 312 ), in which pins for the axial guidance of the fittings ( 33 ) are introduced. Tool according to claim 7 or 8, characterized in that the shaped pieces ( 33 ) lateral holes ( 331 ) for receiving guide pins, via which the fittings are connected together. Tool according to one of claims 7 to 9, characterized in that the punch ( 4 ) an outer axially displaceable stamp part ( 42 ), of an inner axially displaceable pressure pin ( 46 ) is coaxially penetrated, wherein the outer stamp part ( 42 ) a conical section ( 421 ), which with the conical implementation ( 211 ) corresponds to its enlarged diameter end. Tool according to claim 10, characterized in that the outer punch part ( 42 ) in the stamp ( 4 ) via a spring ( 26 ) is biased. Tool according to claim 10 or 11, characterized in that the inner pressure pin ( 46 ) in relation to the outer stamp part ( 42 ) is biased by a spring. Tool according to one of claims 10 to 12, characterized in that the inner pressure pin ( 46 ) in relation to the outer stamp part ( 42 ) is positionable such that the two punch parts a receptacle for the head of a pre-compressed rivet ( 82 ) limit.