DE10124920A1 - Riveting method e.g. for automobile body panels, uses sonotrode for oscillation of rivet at defined frequency - Google Patents

Abstract

The riveting method has the rivet (7) and the parts (4,5) to be riveted together pre-positioned, before application of pressure between an anvil (2) and one of the parts and between a sonotrode (3) and the rivet head (7.1) and movement of the anvil and the sonotrode towards one another. The sonotrode supplies ultrasound waves for oscillation of the rivet at a defined frequency, for melting the contact zone (6) between the rivet and the part contacted by the anvil.

Description

The invention relates to the technical field of working methods in Connection with that of mechanical engineering, especially the connection of Parts in the riveting process with one-piece or multi-piece rivet shapes.

A number of positive, non-positive and material connections, including the methods of their production, in order to be able to connect parts or sheets together, are generally known. Each of these connecting elements and methods is characterized by certain properties and the resulting advantages and disadvantages. In order to be able to connect metal sheets to each other, rivets are also used, such as punch rivets using the riveting process. The type of punch rivet became particularly important with the introduction of aluminum as a material in the body shop of the automotive industry. This type of connection with its technology and elements has been used very frequently since then and in particular in the manufacture of aluminum bodies. Of course, this punch rivet also has disadvantages, which are manifested in the fact that the following, not always feasible requirements must be met in order to make this connection safe with regard to its manufacture for later use of the products, which is a so-called "punch rivet-compatible" design the connection requires:

• - The punch rivet must be able to penetrate a first joining partner.
• - A second joining partner must be formable to a certain extent.
• - Certain material thicknesses and strengths result in use and technological limits.

For this purpose, the closest prior art is the documents DE 196 48 231 A1 and to name the very close DE 197 00 627 A1. The punch riveting method shown in these documents also has the the aforementioned three major disadvantages, especially that of the limited  Sheet thickness and because the forming must still be possible, the limited Material strength, moreover, the lack that no joining with compact bodies is possible. Resilient properties within the Connection is not possible. The technical solution just for these two disadvantages to be presented, which the above. for punch rivet connections The disadvantages presented in summary can be confirmed as follows represent.

When punch riveting, the joining partners must be formable to a certain degree because the first material layer, in both cases here the one on top, punctured by the punch rivet and the second material layer strongly deformed becomes. The sheet thicknesses to be joined are due to the usual rivet length relatively limited and must therefore be kept relatively thin. In case of DE 197 00 627 A1 is certainly not the media tightness of the connection guaranteed because both sheets are pierced. With the technical Solution according to DE 196 48 231 A1, the media tightness is at least serious to question because the high deformation of the second Sheet layer can cause a crack in this sheet layer, at least this cannot be ruled out with absolute certainty. Thus poses this technical solution also has a high media tightness The degree of uncertainty is high Punch riveting force necessary. A mixed construction with metals and Non-metals (e.g. plastics) are not possible with punch riveting. At the Punch rivets are used only with circular rivet cross sections, so that is no security against rotation between the sheets.

The increased use of high-strength or high-strength sheets, including those Aluminum sheets, eliminates the previous technical and economic adverse effects of the known prior art and does not solve hence not the problem, it rather reinforces the problem in particular the vehicle body construction. The media tightness of the previous rivet connections is in turn to certain, in part limiting, thus disadvantageous, material properties of the joining partners bound.  

Of the defects and their causes in the state of the above Starting from technology, the invention is based on the object To provide riveting processes, which are independent of the above. previous A prerequisite is and a much higher one Connection security and media tightness, so much higher Has safety in use of the riveted joint.

According to the invention this object is achieved by the characterizing part of claim 1. Further advantageous features result from the dependent claims. According to the proposed invention, all parts of the future rivet connection are first positioned exactly. Thereafter, when one-piece connecting elements are used, a positive and positive connection between the anvil and the associated part to be joined and, when using multi-part connecting elements, between the anvil and the rivet holder facing the anvil becomes equivalent by defined support of the anvil on the part to be joined or on the Rivet head and a positive and positive connection between the sonotrode and the rivet facing this sonotrode are also produced by a defined support of the sonotrode on the rivet head. The form fit can be produced by a shape-matched indentation or depression on the counterpart of the anvil or a wavy, jagged, corrugated or otherwise unevenly shaped surface of the anvil while at the same time pressing this surface of the anvil into the associated counterpart, the part to be joined or the rivet head , Furthermore, the anvil and sonotrode are moved against each other and the force components 1 and 1 'are built up by means of this. Under defined conditions, the sonotrode causes the rivet, including the adjacent contact zone in the part to be joined, to vibrate under ultrasound at a likewise defined frequency. The same happens when using multi-part connecting elements at the shaft ends of the rivet. The contact surface between the rivet shaft end and the part to be joined on the one hand or between the two rivet shaft ends on the other hand are melted on both sides and the parts contacted under pressure are melted. During and / or after melting, there is a further relative movement of the sonotrode and anvil relative to one another until the rivet head, which was still in contact-free relationship with respect to the part to be joined, comes to rest on the part to be joined. With this procedure, more than just two parts to be joined can be riveted. The connecting element created after the method is carried out is used in the method implementation as a one-part or multi-part connecting element or from several rivets. The connecting elements rivets to be used according to the method are designed longer in their single shaft length in the case of a one-piece design and in the sum of their shaft lengths in the case of a multi-piece version than the individual thickness of the sheet metal adjacent to the rivet in the case of a one-piece version or, in the case of a multi-piece version, the sum of the individual thicknesses associated therewith parts. The rivet shafts can be full or hollow. Rivets in the form of disc springs can be used as connecting elements. In accordance with the method, a form, force and material bond is finally established in the connection.

The solution according to the invention is characterized by the following advantageous Effects from. When using one-piece fasteners, a media-tight conclusion reached. They are also brittle and very hard Connectable metal alloys. In contrast to the comparable state of the Technology according to DE 197 00 627 A1 are in the proposed Procedure also connections with very high sheet thicknesses or with Compact components possible. The rivet buckles due to the high Rivet setting forces as in DE 197 00 627 A1 and DE 196 48 231 A1 is not possible because there are no large pressure forces when establishing the connection between the ultrasonic rivets and sheets are necessary. Furthermore this procedure guarantees security against twisting of those to be joined Share, as non-circular connection cross-sections can also be used. Through the use of rivets, which are designed as disc springs, or those who can be given such functions can have a defined preload  be provided in the connection by spring action. In the Procedure with two-part rivet can the rivet material with the material of the respective adjacent sheet are brought into line, which causes corrosive effects due to contact with each other different materials can be avoided. However, everyone can Materials are joined together and it is also a hybrid construction possible between metals and non-metals (e.g. plastics)

The following exemplary embodiments are intended to explain the invention in more detail.

Show it:

Fig. 1 vertical sectional view of an arrangement for performing the riveting method according to the invention with a one-piece rivet

Fig. 2 vertical sectional view of an arrangement for performing the riveting method according to the invention with a multi-part rivet

Embodiment 1

First of all, the parts of the arrangement for carrying out the riveting process and the parts 4 and 5 to be riveted are positioned in this as well as the rivet 7 in the bore of part 4 . Between anvil 2 and the part 5 to be joined, a positive and positive connection is produced by a serrated surface 9 of the anvil 2 and the pressing of this surface 9 into the part 5 to be joined . At the same time, the force and form fit is produced by a defined support of the sonotrode 3 on the rivet head 7.1 by means of a likewise serrated surface 9 on the sonotrode 3 and pressing it into the rivet head 7.1 between the rivet 7 and the sonotrode 3 . Anvil 2 and sonotrode 3 act against each other with a force 1 and 1 '. The sonotrode 3 acts as a device element moved with ultrasound. The sonotrode 3 vibrates with the rivet 7 at a defined frequency. The part 5 to be joined is kept at rest by the anvil 2 . During the advancing movement of the sonotrode 3 against the anvil 2 , the rivet 7 is pressed against the part 5 to be joined . The rivet 7 first touches the part 5 to be joined with the rivet shaft 7.2 . The rivet head 7.1 still remains in contact with the part to be joined with it. Through defined process conditions with regard to pressure and ultrasound frequency, a welding zone is formed on the contact surface between the rivet shank 7.2 and the part 5 to be joined . By fusing the rivet shank 7.2 with the part 5 to be joined, the length of the rivet shank 7.2 is shortened until the rivet head 7.1 comes to rest on the part to be joined. With appropriate material coordination between the rivet and the material to be connected, the rivet head can also be welded to the resulting contact surface. The connection is thus given a shape and a hitherto unknown substance bond. If the rivet head is designed constructively in the form of a plate spring, a further new effect is achieved, namely that of a pretensioning force in the newly created connection. Such rivet connections with pre-tensioning force integrated by the manufacturing process are so far unknown to the person skilled in the art.

Embodiment 2

This embodiment shows the advantageous inventive method using the example of multi-part riveting. Here one works with a rivet half 7 and a rivet half 8 . By means of defined supports on the rivet heads 7.1 and 8.1 , positive and non-positive connection to the anvil 2 as well as to the sonotrode 3 are produced analogously to embodiment 1 after the required positioning. Here too, anvil 2 and sonotrode 3 act against one another with a force 1 and 1 '. The sonotrode 3 vibrates with the rivet 7 at a defined frequency. The rivet half 8 is held at rest by the anvil 2 .

During the advancing movement of the sonotrode 3 against the anvil 2 , the rivet 7 is pressed against the part 5 to be joined . The advancing movement of the sonotrode 3 against the anvil 2 touches the two rivet shafts 7.2 and 8.2 . The rivet head 7.1 , 8.1 initially remains without touching the part 4 , 5 to be joined. A welding zone is formed on the contact surface between rivet shank 7.2 and rivet shank 8.2 by likewise defined process conditions with regard to pressure and ultrasound frequency. By merging the two rivet shafts 7.2 and 8.2 , the length of the two rivet shafts is shortened until the rivet heads 7.1 and 8.1 come to rest on the parts 4 and 5 to be joined. With appropriate material coordination between the rivet and the material to be connected, the rivet head can also be welded to the resulting contact surface. Here, too, the connection receives a form and previously unknown material connection, and, in the case of a plate spring configuration of the two rivet halves, a previously unreachable pretensioning force within the rivet connection. This results in further particularly favorable technical effects and advantages for the products in vehicle and plant construction shown below. Hybrid designs can thus be used to connect metals and non-metals. Sheet metal connections with at least one completely smooth and media-visible surface side can be manufactured. It is possible to position components and metal sheets using an anti-rotation device.

Claims (9)

1. A method for connecting parts with connecting elements designed as riveting characterized in that
that after prior positioning of the riveting device and all parts of the future rivet connection, a positive and positive connection between the anvil ( 2 ) and the part to be joined ( 5 ), synonymous between the anvil ( 2 ) and the rivet half ( 8 ) by a defined support of the anvil ( 2 ) on the part to be joined ( 5 ) / the rivet head ( 8.1 ) on the one hand and a positive and positive connection between the sonotrode ( 3 ) and the rivet ( 7 ) by a defined support of the sonotrode ( 3 ) on the rivet head ( 7.1 ) will be produced,
then anvil ( 2 ) and sonotrode ( 3 ) are moved against each other and by means of which the force components 1 and 1 'are built up,
that under defined conditions, the sonotrode ( 3 ) vibrates the rivet ( 7 ) at a defined frequency, including the adjacent contact zone ( 6 ) in the part ( 5 ) to be joined, synonymous at the end of the rivet shaft ( 8.2 ), the contact zone ( 6 ) melts on both sides and the parts contacted under pressure are melted,
that afterwards a further relative movement of the sonotrode ( 3 ) and anvil ( 2 ) takes place against each other until the rivet head ( 7.1 , 8.1 ), which until then has been in contact-free position with respect to the part ( 4 , 5 ) to be joined, fits snugly on the part to be joined ( 4 , 5 ) comes into circulation. 2. The method according to claim 1, characterized in that positive locking by a shape-matched screwing or countersinking on the counterpart of the anvil ( 2 ) or a wavy, jagged, corrugated or otherwise uneven surface ( 9 ) of the anvil ( 2 ) while simultaneously pressing it thus designed surface ( 9 ) of the anvil ( 2 ) into the associated counterpart, the part to be joined ( 5 ) or the rivet head ( 8.1 ). 3. The method according to claim 1 and 2, characterized in that a similar positive connection between the sonotrode ( 3 ) and the rivet ( 7 ) is produced. 4. The method according to claim 1, characterized in that more (Y) than only two parts to be joined ( 4 , 5 ) are riveted. 5. The method according to claim 1, characterized in that the connecting element formed after the implementation of the method during the implementation of the method as a one-piece ( 7 ) or multi-part connecting element (7 + 8 +... + X) or from several rivets ( 7 , 8 ,. . X) is used. 6. The method according to claim 1, characterized in that the connecting elements to be used according to the method of the rivet ( 7 ) (in the case of a one-piece version in their individual shaft length and in the case of a multi-piece version in the sum of their shaft lengths are longer than the individual thickness of the sheet metal which is in contact with the rivet in the case of a one-piece version) ( 4 ) or, as a multi-part design, the sum of the individual thicknesses of the parts to be joined ( 4 , 5 , Y). 7. The method according to claim 1, characterized in that the shafts ( 7.2 , 8.2 ) of the rivets to be used as connecting elements according to the method are designed to be full or hollow. 8. The method according to claim 1, characterized in that rivets in the type of disc springs are used for carrying out the method as connecting elements ( 7 , 8 ). 9. The method according to claim 1, characterized, that as a result of the process a form, force and material connection in the connection is established.