DE102014206787A1 - Semi-punched rivet with large punch diameter and method for producing a workpiece composite - Google Patents

Abstract

The invention relates to a semi-hollow punch rivet (100) for pre-punch-free joining of workpieces, comprising a rivet head (110) and a rivet shank (122) adjoining it, wherein the rivet shank (122) is formed with a concentric recess (121) and has a rivet foot (124 ) having a punching edge (127). It is envisaged that the rivet foot (124) circumferentially has a larger outer diameter than the rest of the rivet shank (122). The invention further relates to a method for producing a workpiece composite using at least one such semi-hollow punch rivet (100).

Description

The invention relates to a Halbholstanzniet for pre-punching joining of workpieces.

The invention further relates to a method for producing a workpiece composite using at least one semi-hollow punch rivet.

Semi-holing punch rivets for pre-punch-free joining of workpieces and thus executable joining method for pre-punching joining of workpieces by producing a Stanznietverbindung are known from the prior art, including, for example. On the patents DE 10 2009 050 342 B4 and DE 199 05 528 A1 is pointed out. Complementing is also on the patent DE 199 09 821 A1 pointed.

The invention has for its object to provide a Halbholstanzniet and a method for producing a workpiece composite of the type mentioned, which do not have at least one associated with the prior art disadvantage or at least only to a reduced extent.

This is achieved with a Halbhohlstanzniet according to the invention according to the features of claim 1 and with a method according to the invention for producing a workpiece composite according to the features of the independent claim. Preferred developments and refinements emerge analogously for both subject matters of the invention both from the dependent claims and from the following explanations.

The semi-hollow punch rivet according to the invention for pre-hole-free joining of workpieces has a rivet head and a rivet shank adjoining it, wherein the rivet shank is formed with a concentrically arranged recess and has a rivet foot with (at least) one punching or cutting edge. It is envisaged that the Nietfuß circumferentially (ie, at each circumferential location) has a larger outer diameter than the rest or other rivet shank, whereby also during the joining process with this Nietfuß producible in the rivet head workpiece punching hole has a larger diameter than the punched hole this finally projecting shaft portion of the riveting shank. This results in a radial gap between the (relevant) shaft portion and the punching hole wall, which allows a relative movement of the joined workpieces at the joint transverse to the joining axis of the Stanznietverbindung or transversely to the longitudinal axis of the Halbhohlstanzniets.

In other words, the rivet shank of a half-holed rivet according to the invention has its largest outer diameter in the region of the rivet base, whereby the punch hole produced in the rivet head-side workpiece with this rivet foot is larger than the remaining rivet shank, so that the rivet shank and, in particular, its axial adjoining the rivet head Shank portion can be received with circumferential radial gap in this punched hole or is receivable. The conditional relative mobility between the joined workpieces (transverse to the joining or longitudinal axis) resulting from the radial free space in particular makes it possible to achieve different thermal expansion without the rivet element and / or the workpieces being damaged. The produced Stanznietverbindung is less stressed and a failure is unlikely.

A semi-hollow punch rivet according to the invention is preferably rotationally symmetrical (with respect to its longitudinal axis), wherein provision is made in particular for the rivet head to project beyond the rivet shank in the radial direction in the manner of a hat.

Preferably, the axial shaft portion of the rivet shank adjacent to the rivet head is cylindrical. The rivet foot preferably has a diameter which is larger by 1.0 mm to 3.0 mm and in particular by 1.5 mm to 2.0 mm with respect to this shaft section.

The rivet shank can be formed with a conically widening end section, whereby the rivet foot has a larger diameter than the shank section adjoining the rivet head.

The rivet shank may also be formed with a cylindrical end section, this end section having a larger diameter than the shaft section adjoining the rivet head.

The Halbholstanzniet invention is preferably made of a steel material, in particular a case steel formed. Preferably, the Halbholstanzniet invention also has a coating which is applied at least on the outside. The coating can prevent corrosion and / or simplify the joining process (setting process).

The Halbholstanzniet invention can be made by machining or forming. A machining can, for example, be done by turning. A reshaping production can take place, for example, by extrusion and subsequent upsetting of the rivet shank. Preferably, therefore, it is a turning or forming part.

• – Positionieren und Ausrichten der zu fügenden Werkstücke;
• – Ausführen eines Fügevorgangs zum vorlochfreien Fügen der Werkstücke mittels bzw. unter Verwendung von wenigstens einem erfindungsgemäßen Halbhohlstanzniet (d. h. das Fügen erfolgt an wenigstens einem Fügepunkt bzw. einer Fügestelle); und
• – Durchführen bzw. Ausführen eines Beschichtungsprozesses, im Zuge dessen die gefügten Werkstücke auch erwärmt werden und am Fügepunkt bzw. an den Fügepunkten zueinander eine bedingte Relativbewegung (d. h. im Rahmen des radialen Spalts zwischen dem Nietschaft und der Stanzlochwandung im nietkopfseitigen Werkstück) ausführen können.

The method according to the invention for producing a workpiece composite having at least two workpieces comprises at least the following steps:

• - positioning and aligning the workpieces to be joined;
• Performing a joining operation for pre-punch-free joining of the workpieces by means of or using at least one semi-hollow punch rivet according to the invention (ie the joining takes place at at least one joining point or a joint); and
• Performing or carrying out a coating process in which the joined workpieces are also heated and at the joining point or at the joining points to each other a conditional relative movement (ie within the radial gap between the rivet shank and the punching hole in nietkopfseitigen workpiece) can perform.

The coating process may be a conventional painting process for applying or applying a topcoat, wherein when heated (for curing the applied paint) temperatures of up to 80 ° C and more can be achieved.

The coating process is preferably a cathodic dip coating of the joined workpieces and subsequent heating (for curing the applied coating), which can also be referred to collectively as KTL process or CDP pass. A cathodic dip coating is used in particular as a corrosion protection coating and / or as a base coat. The curing is preferably carried out at a temperature between 180 ° C and 210 ° C. A subsequent to the joining process KTL-run leads to a high corrosive and optional use of an adhesive (see below) and high mechanical strength of the workpiece assembly produced.

Preferably, at least at the upper (or rivet head side or punch side) workpiece is a sheet metal workpiece or a sheet-like workpiece, this workpiece is punched or pierced during a joining operation of Nietfuß used semi-punched rivet, before this with the lower of nietkopfseitigen workpiece remote workpiece (or with the matrizenseitigen workpiece) is positively pressed. The rivet shank and the workpiece in question are locally plastically deformed during pressing. The punching waste (slug) remains in the recess of the hollow rivet shaft. In an analogous manner, more than two workpieces can be joined, wherein both the upper workpiece and the at least one middle workpieces are punched before the rivet shank is pressed on the foot side with the lower or the rivet head side workpiece facing away from the workpiece.

The workpiece assembly to be produced is in particular a body component, body component or body component for a motor vehicle (in particular for a car body).

Preferably, the workpieces are formed from different metal materials. In particular, these various metal materials have a different thermal expansion. One of the workpieces, in particular the rivet-head-side workpiece, may be formed from an aluminum material, for example an aluminum sheet, and the other workpiece from a steel material, for example a steel sheet.

At least one of the workpieces, in particular the rivet-head-side workpiece, may also be formed from a fiber-reinforced plastic material, for example CFRP or GFRP, the other workpiece being made of a metal material, for example an aluminum material (in particular aluminum sheet) or a steel material (in particular steel sheet material), may be formed (so-called hybrid or mixed construction).

It is preferably provided that the workpiece formed from fiber-reinforced plastic material is pierced or punched during the joining process and that a radial gap between the shaft portion and the punching hole in this workpiece is formed, which allows a relative movement of the joined components at the joint during heating, whereby a critical shear stress of the Halbhohlstanzniets and / or critical Lochleibungspressungen, in particular in the punching hole wall of the formed of fiber-reinforced plastic material workpiece can be prevented.

The procedure according to the invention is thus optimally suited with regard to the production of rivet-jointed hybrid or mixed construction composites (in particular CFRP metal composites) with subsequent cathodic fluid flow pass.

Preferably, the workpieces are additionally glued together, wherein it is preferably provided that the adhesive used hardens during heating in the course of the coating process and in particular during heating in the context of cathodic dip painting (that is, in the KTL run).

The invention will now be described by way of non-limiting example with reference to FIG the schematic and not to scale figures explained in more detail. However, the features shown in the figures and / or explained below may, regardless of specific feature combinations, be general features of the invention.

1 shows in two individual representations a Halbhohlstanzniet invention.

2 1 shows a detail of a sectional view using a plurality of semi-hollow punch rivets according to FIG 1 produced workpiece composite.

3 shows in two individual representations another half-punched rivet according to the invention.

1 shows a semi-hollow punch rivet 100 who has a rivet head 110 and a subsequent riveting 120 having. The left representation ( 1a ) shows a side view and the right representation ( 1b ) shows a sectional view. The semi-hollow punch rivet 100 is formed with respect to its longitudinal axis L rotationally symmetrical. The rivet head 110 projects beyond the rivet shank in the radial direction 120 , The rivet head 110 groundbreaking end of the rivet 120 is called a rivet foot 125 designated. The rivet foot 125 has a circumferential punching or cutting edge on the front side 127 on. Further, the rivet shaft 120 formed hollow, what this in a known manner from the Nietfuß 125 outgoing and moving in the direction of the rivet head 110 extending, concentrically arranged recess 121 has, as seen from the sectional view. The rivet head 110 may also have a different configuration and, for example, be designed as a countersunk head.

According to the invention it is provided that the Nietfuß 125 circumferentially a larger outer diameter D than the rest of rivet shank 120 and especially as the rivet head 110 adjacent cylindrical shaft section 122 having. For this is the riveting 120 with a conically widening end section 124 trained so that the rivet foot 125 a larger diameter than the adjacent to the rivet head cylindrical shaft portion 122 having. The diameter D of the rivet foot 125 is, for example, by 1.0 mm to 3.0 mm and in particular by 1.5 mm to 2.0 mm larger than the diameter d of the proximal shaft portion 122 , (The rivet foot 125 could z. B. have a diameter D of about 7 mm and the proximal shaft portion 122 could have a diameter d of only about 5.0 mm). The cone angle a of the outer peripheral surface in the end portion 124 is preferably in a range of 40 ° to 50 °.

The in 2 shown workpiece assembly 200 includes an upper workpiece 210 and a lower workpiece 220 , which at several joining points or points, each with a semi-hollow punch rivet 100 according to 1 are joined. The workpieces 210 and 220 Optionally also with an adhesive 230 be glued. For the workpieces 210 and 220 By way of example, these are sheet metal workpieces or sheet-like workpieces. The lower workpiece 220 is formed of a plastically deformable material, such as, for example, an aluminum or steel sheet. (At the lower workpiece 220 it could also be a profile part, casting or the like.) The upper workpiece 210 can also be formed from a plastically deformable material, such as. An aluminum or steel sheet, or from a plastically non-deformable material, such as. A GFRP or CFRP material. The joint area within which the two workpieces 210 and 220 are joined together, may deviate from the flat course shown also have a spatial course.

The joining takes place in a manner known per se, the upper or nietkopfseitige workpiece 210 from the riveting stock 120 the semi-hollow punch rivet used 100 punched or pierced before this with the lower workpiece 220 positively and undercut is pressed. The conical or apron-like configuration of the rivet end section 124 and those in the direction of the rivet foot 125 decreasing wall thickness (the wall thickness or wall thickness of the hollow rivet shaft 120 takes off from the rivet foot 125 in the direction of the rivet head 110 to, or vice versa, as from the sectional view in 1 visible) simplify the spreading and the positive-locking undercut pressing with the lower workpiece 220 , The upper workpiece 210 becomes at the joint between the radially projecting rivet head 110 and the lower workpiece 220 trapped and until the curing of the optional adhesive 230 only fixed by this clamp. The punching of the upper workpiece 210 accumulating waste piece 211 becomes permanent in the interior recess 121 of the rivet shaft 120 added.

The axial length of the rivet shank 120 and the axial lengths of the rivet shank portions 122 and 124 depend on the thickness of the workpieces to be joined 210 and 220 , The diameter of the rivet head 110 and the shaft portions 122 and 124 can be dimensioned according to different criteria (eg., Material strength, bond strength to be achieved, workpiece thickness and the like).

At a joint this points in a joining process with the help of Nietfußes 125 and the punching edge formed thereon 127 trained through hole 215 in the upper or nietkopfseitigen workpiece 210 a larger diameter than that of this punch hole 215 finally towering shaft near shaft section 122 the semi-hollow punch rivet 100 on. This results in a radial gap S between this shaft portion 122 and the punching hole wall, whereby at the joint a conditional relative movement or relative displacement of the joined workpieces 210 and 220 transverse to the joining axis or longitudinal axis L of the semi-hollow punch rivet 100 is possible. The total between the workpieces 210 and 220 allowed relative movement is in 2 illustrated with the arrows R. The free spaces at the joints given by the gaps S allow, in particular, the largely stress-free expansion of the workpiece with the higher coefficient of material thermal expansion, for example during the heating phase of a cathodic fluid passage. Further, tilting of the semi-hollow punch rivet 100 and damage to selbiger and / or the workpieces 210 / 220 prevented.

The radial gap dimension of the gap S specifies the possible range of motion at a joint or a joining point. The semi-hollow punch rivet is preferred 100 such that the resulting gap S during heating of the workpieces 210 and 220 , in particular in the course of a cathodic dip painting (ie in KTL run), a resulting different thermal expansion of the workpieces 210 and 220 allows at the joint, causing damage to the rivet element 100 and / or on the workpieces 210 / 220 avoided and from which also further advantages result. The radial gap dimension of the gap S results from the diameter difference (D - d) between the rivet foot 125 and the proximal shaft portion 122 , According to the above-mentioned preferred diameter difference (D-d) of 1.0 mm to 3.0 mm and in particular of 1.5 mm to 2.0 mm, a preferred radial gap of the gap S of 0.5 mm to 1 results, 5 mm and in particular from 0.75 mm to 1.0 mm.

3 shows another embodiment of a semi-hollow punch rivet according to the invention 100 ' , at the rivet stock 120 ' a cylindrical end portion 124 ' having the diameter larger than that of the rivet head 110 ' adjacent cylindrical shaft section 122 ' is trained. Between the rivet sections 122 ' and 124 ' there is an edge-free transition area 123 ' , The cylindrical end portion 124 ' points opposite the conical end section 124 the in 1 and 2 embodiment shown a higher deformation resistance and a higher rigidity, whereby workpieces of firmer and / or brittle materials are easier pierceable or punched. Otherwise, the previous explanations regarding the 1 and 2 , in particular also with regard to the mentioned diameter ratios.

LIST OF REFERENCE NUMBERS

100

 Semi-hollow punch rivet (rivet element)

110

 rivet head

120

 rivet

121

 Recess (cavity)

122

 Shaft section (close to the head)

123

 Transition area

124

 Shank section, end section

125

 rivet foot

127

 punching edge

200

 Workpiece composite

210

 workpiece

211

 Waste piece (slug)

215

 punch hole

220

 workpiece

230

 Adhesive, adhesive layer

D

 diameter

L

 Longitudinal axis, joining axis

R

 relative movement

S

 gap

a

 angle

d

 diameter

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 102009050342 B4 [0003]
• DE 19905528 A1 [0003]
• DE 19909821 A1 [0003]

Claims (10)

Semi-hollow punch rivet ( 100 ) for pre-punch-free joining of workpieces ( 210 . 220 ), with a rivet head ( 110 ) and an adjoining rivet ( 120 ), whereby the rivet shank ( 120 ) with a concentric recess ( 121 ) is formed and a Nietfuß ( 125 ) with a punching edge ( 127 ), characterized in that the rivet foot ( 125 ) circumferentially a larger outer diameter (D) than the rest of rivet shank ( 120 ), whereby also during the joining process in rietkopfseitigen workpiece ( 210 ) with the rivet foot ( 125 ) producible punch hole ( 215 ) has a larger diameter than that of this punched hole ( 215 ) finally projecting shaft section ( 122 ) of the riveting shaft ( 120 ) having. Semi-hollow punch rivet ( 100 ) according to claim 1, characterized in that the to the rivet head ( 110 ) adjoining shank portion ( 122 ) is cylindrical, wherein the Nietfuß ( 125 ) with respect to this shaft portion ( 122 ) has a diameter (D) larger by 1.0 mm to 3.0 mm and in particular by 1.5 mm to 2.0 mm. Semi-hollow punch rivet ( 100 ) according to claim 1 or 2, characterized in that the rivet shank ( 120 ) with a conically widening end section ( 124 ), whereby the rivet foot ( 125 ) has a larger diameter (D) than that of the rivet head ( 110 ) adjoining shank portion ( 122 ) having. Semi-hollow punch rivet ( 100 ' ) according to claim 1 or 2, characterized in that the rivet shank ( 120 ' ) with a cylindrical end portion ( 124 ' ), this end portion ( 124 ' ) has a larger diameter than that of the rivet head ( 110 ) adjoining shank portion ( 122 ' ) having. Semi-hollow punch rivet ( 100 ) according to one of the preceding claims, characterized in that it is formed from a steel material and in particular also has a coating. Semi-hollow punch rivet ( 100 ) according to one of the preceding claims, characterized in that it is made by machining or forming. Method for producing a workpiece composite ( 200 ) with at least two workpieces ( 210 . 220 ), comprising the following steps: - positioning and aligning the workpieces ( 210 . 220 ); - pre-hole-free joining of workpieces ( 210 . 220 ) using at least one semi-hollow punch rivet ( 100 ) according to any one of the preceding claims; and - performing a coating process in which the joined workpieces ( 210 . 220 ) are heated and at the joining point to each other can perform a conditional relative movement (R). Method according to claim 7, characterized in that the workpieces ( 210 . 220 ) are formed of various metal materials. Method according to claim 7, characterized in that at least one of the workpieces ( 210 . 220 ), in particular the rivet head side workpiece ( 210 ), of a fiber-reinforced plastic material and the other workpiece ( 220 . 210 ) is formed of a metal material. Method according to claim 7, 8 or 9, characterized in that the workpieces ( 210 . 220 ) are additionally glued together, wherein it is provided in particular that the adhesive used ( 230 ) hardens during heating in the course of the coating process.

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