EP2861362A1

EP2861362A1 - Method for connecting workpieces, and connection device

Info

Publication number: EP2861362A1
Application number: EP12798243.7A
Authority: EP
Inventors: Johann Kaussler
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2012-07-12
Filing date: 2012-11-26
Publication date: 2015-04-22
Also published as: WO2014008960A1; DE102012212214A1; CN104661771A; MX2015000496A

Abstract

Disclosed are a method and a device for connecting workpieces (8, 9), said device comprising a welding head that can be used for welding and riveting. Said method comprises the steps of: providing a resistance welding head (2, 3) that has at least two electrodes (3, 4); replacing at least one of the electrodes (3, 4) by a rivet header (24, 25) or equipping at least one electrode (3, 4) with an adapter piece (23) comprising a rivet header; placing two workpieces (28, 29), each of which has an opening (31, 32), between the electrodes (3, 4) or the rivet headers (24, 25) of the resistance welding head (2) in such a way that the openings (31, 32) are coaxial; inserting a connecting element (36) in the openings (31, 32); and riveting the workpieces (28, 29) together, the connecting element (36) being deformed with the help of the electrodes (3, 4) and/or the rivet header (24, 25).

Description

description

Method for connecting workpieces and connecting device

The following invention relates to a method for joining workpieces and a connection device. Workpieces, such as parts of electrical equipment, are usually connected together as parts to be joined during production. Bonding takes place, for example, by soldering,

Welding or riveting at joints. It is thereby achieved a positive or non-positive connection of the workpieces. Usually in production processes different

Assembly or manufacturing stations provided at which, for example, welding heads for welding, riveting riveting or soldering stations for soldering connection of the components are kept.

In conventional resistance welding electrically conductive workpieces are heated by an electric current until melting, so that a common melt takes place and after solidification there is a welded joint between the workpieces. Known resistance welding heads are designed in terms of their design to high temperatures and high electrical currents. In most cases, welding also requires that the two electrodes of the resistance welding head simultaneously exert a welding force on the joint during the welding process.

In the manufacture of electromechanical components parts are often riveted together. In this case, flat sections of components are connected by rivet holes by means of a rivet. When corresponding riveting, it is necessary to provide a rivet pin, which be ^¬ is of deformable material to deform so that rivet heads are formed Kgs ^¬ NEN. In particular, in the production of medium-sized electromechanical components complicated automated assembly systems are required with a variety of joining stations due to the necessary different joining or connecting process. It would be desirable to simplify the manufacturing effort of components or workpieces comprising multiple joints with different types of joints. Accordingly, it is an object of the present invention to provide an improved method and / or apparatus for joining workpieces.

Accordingly, a method for joining workpieces is proposed, which comprises:

Providing a resistance welding head with Minim ^¬ least two electrodes;

Replacing at least one of the electrodes by a rivet head setter or providing at least one electrode with an adapter piece comprising a rivet head setter;

Positioning two workpieces each having an opening between the electrodes or the rivet head setters of the resistance welding head such that the openings are coaxial;

Inserting a connecting element in the openings; and

Riveting the workpieces with each other, wherein the connecting element is deformed by means of the electrodes and / or the Niet ^¬ head setter.

The method provides to use a designed as a resistance welding head welding head for riveting and in particular for hot or hot riveting. Specifically, a resistance welding head with coaxially arranged electrodes, which enclose, for example, from above and below to be connected to two working ^¬ pieces, can be used as riveting station by an appropriate change of the electrodes. Become at- For example, both electrodes verse ^¬ hen with an adapter that act as Nietkopfsetzer, pin-shaped connecting elements can be used as a rivet. For example, the electrodes can also be exchanged, the new changed electrodes being designed as rivet head setters. It is conceivable that the modified electrodes or adapter pieces have the same material as the electrodes for ^resistance welding. In particular, it is conceivable that the modified electrodes or adapter pieces have the same electrical resistance as the electrodes for resistance welding ^¬ .

It is thus possible to use a manufacturing station, which includes the resistance welding head, flexible for welding as well as for riveting. This results in improved system flexibility in automated or automated assembly systems.

In embodiments of the method, there is also an input of an electric current through the electrodes and / or the Nietkopfsetzer and the connecting element for heating the connecting element.

This respect, a hot riveting can be realized, wherein Wi through the resistor of the connecting element the same is heated due to the flowing ^¬ sequent electric current. In a entspre ^¬ sponding Warmnietprozess the connecting element or the rivet expands due to the heat supply during the riveting process from being deformed by means of resistance welding head or formed as Nietkopfsetzer electrodes and then cooled. Upon cooling of the rivet shrinks insbeson ^¬ particular the rivet shank and leads to an improved strength of the pressed together frictional workpieces or components together.

In embodiments, the electrodes, the electrodes provided with adapter pieces or the electrodes designed as rivet head setters are relatively connected during riveting. oscillated by side along duri ^¬ fenden through the connecting element acting axis.

This respect takes place in particular during a movement of the electric, adapters or Nietkopfsetzer against each other, an oscillating force is applied and thus an easier Verfor ^¬ mung of the connecting element towards a rivet shank and rivet heads. In this case, preferably an oscillating hot riveting with two-sided force entry on a cylindrical see pen as a connecting element. For example, the electrodes and / or the Nietkopfsetzer the resistance welding head are mounted sprung with respect to the axis of action.

In embodiments of the method, the workpieces are held sprung in a workpiece holder. With the help of the fe ^¬ stop holding results in a homogeneous force entry in particular ^¬ special, when the electrodes or the Nietkopfsetzer are relatively moved against each other and act on the connecting element to be deformed.

Embodiments of the method provide that at least three workpieces, which each have an opening, are riveted to a connecting element. For example, they may be bimetallic strips used in relays or electromechanical switches.

In embodiments of the method it is provided that the two, ie both electrodes are each replaced by a Nietkopfset ^¬ zer or both are provided with an adapter piece, which includes a Nietkopfsetzer. With

Help the two Nietkopfsetzer is then the Verbindungsele ^¬ ment deformed. In this respect, cylindrical connection ^¬ elements can deform to rivets. In variants of the process of the resistance welding head is configured such that two workpieces are heated at a welding site to the on ^¬ melt with the aid of an electric current. In this respect, a resistance Welding conceivable in the context of the method with the resistance ^¬ welding head.

Variants of the method include the steps:

Providing the resistance welding head without rivet head ^¬ setter;

Positioning the two other workpieces between the electrodes; and

Welding the two other workpieces with the help of

Resistance welding head ^miteinan at the weld ^{miteinan ¬} .

Preferably, in such a way be moved ^¬ during welding, the welding head that the two electrodes are moved relative to the welding point, and a constant force is applied to the welding point. Due to the constant force, which can be ^¬ example, by a spring-mounted mounting of the two electrodes to each other, a fusion or welding of the two workpiece materials results particularly low with each other.

In this respect, in the proposed method, the electrodes are used for welding or riveting depending on the connection method, which is necessary in particular in a production line.

It is also proposed a connecting device for connecting workpieces together with a resistance welding head. The resistance welding head comprises at least two electrodes, wherein the resistance welding head is ^{ausgestal ¬} Tet, to heat with the aid of an electric current, the workpieces at a weld until melting. At least one electrode is ausges taltet ^¬ as Nietkopfsetzer.

For example, the connecting device is provided with a STEU ^¬ ereinrichtung which such a way by a current which both electrodes controls or causes a resistance welding takes place.

The connection device is set up to carry out a method as described above.

In embodiments of the connecting device, a holding device for the sprung storage of the workpieces is further provided. A resilient mounting allows a homogeneous force, in particular on both sides or ends of a connecting element.

The connection device further comprises, in embodiments, drive means for moving the electrodes and / or the rivet head setter (s) on an axis of action relative to each other. As drive means, for example, a pneumatic drive or an electric drive in question. Actuators or servos can also be used as drive devices. In this case, the drive means should develop sufficient force to compress the workpieces during welding and to deform during riveting the connecting element or the rivet and rivet head, which is heated in particular by a current flow.

In embodiments of the connecting device, the electrodes and / or the Nietkopfsetzer are resiliently mounted with respect to an axis of action. The resilient mounting also allows a particularly homogeneous force influence on the workpieces or Verbindungsele ^¬ elements to be joined together.

Other possible implementations of the invention include not explicitly mentioned combinations of above or below with respect to the embodiments described method steps, features or embodiments of the Ver ^¬ driving or the connecting device. The person skilled in the art will also consider individual aspects as improvements or additions add or modify to the respective basic form of the invention.

The above-described characteristics, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be described in detail in conjunction with the drawings.

Showing:

Figure 1, 4, 6 are schematic representations of an embodiment ^¬ example of a connecting ^device for explaining aspects of a method for connecting workpieces.

Figure 2 is a perspective view of a ^¬ exporting approximately example of a welding head for ^¬ A kit in a method for joining work pieces;

Figure 3 is a schematic representation of an example of exporting approximately ^¬ a welding head for He ^¬ purification of aspects of a method for joining workpieces.

Figure 5, 7 are schematic detail views of the embodiment of a connecting device of Figures 1, 4, 6 for explaining aspects of a method for joining workpieces.

In the following figures, embodiments of welding heads and a connecting device as a joining station are shown schematically. In this case, operating situations of the respective connection device are shown in order to aspects of the method of bonding using a resistance welding head.

Fig. 1 shows a connecting device for joining or joining workpieces together. The connecting device 1 in this case comprises two formed as a resistance welding heads weld heads 2, 3. Each welding head 2, 3 has an electrode 4, 5, with the aid of an elastic elemene ^¬ tes 8, 9 is resiliently mounted. It is a movement 16, 17 of the welding heads or electrodes 4, 5 along an axis of action 18 possible. For this purpose, the two welding heads 2, 3 are each coupled to a drive device 11, 12, for example an electric motor or a pneumatic system. The respective drive 11, 12 can supply the corresponding control signals CT to the drive devices by means of a control device 13, along the arrows 16, 17, ie along the effective axis 18. In this respect, a movement of the electrodes along the effective axis 18 takes place coaxially with one another. It is a workpiece holder 10 is provided, can be held in the workpieces 6, 7 to be joined. In an operating situation, the workpieces, as shown in Fig. 1, positioned between the electrodes 4, 5 and clamped by suitable control of the drives 11, 13 of the electrodes 4, 5. In resistance welding, an electric current 14 is generated by the electrodes, the two workpieces 6, 7 in a weld area 15 and the electrode 5. In particular, since the electric resisting ^¬ state of the electrodes 4, 5 is lower than the electrical resistance of the workpieces to be joined 6, 7, the material of the workpieces 6, 7 at the welding point 15 on heated. The welding heads 2, 3 or the control device 13 controls a current 14 in such a way that the workpiece materials 6, 7 melt and fuse or weld together at the welding point 15. At the same time a homogeneous

Force input from above and from below by the resilient mounting of the electrodes 4, 5. 2, an embodiment of a sweat ^¬ head 2 is indicated in perspective. 2, the active axis 18, along which in the embodiment of the welding head the electrode 4, which is held in a Elektrodenauf- 21 by a fastening 22, the resilient bearing 8 and the drive 11, 42 are coaxial.

The electrode holder 21 and electrode attachment 22 are held in suitable guide rails 19, which is held along the axis 18 with a spring element 8, which is arranged around a piston and abuts on a spacer sleeve 20. The shaft not provided with a reference numeral is moved by a pneumatic cylinder 42, which is activated by the drive 11. The linear arrangement of drive 11, 42, the elastic bearings 8, 20 and

Guide 19 of the electrode 4 allows a particularly favorable force transmission to the present in the orientation of FIG. 2 weld below the electrode 5. The welding head 2 also allows use as a rivet head ^¬ or riveting. In this respect, the connection device can also be used as a joining station 1 for hot riveting processes. FIG. 3 shows schematically method ^steps which are carried out in a connection method for riveting workpieces with one another or with the connection device 1, as shown in FIG. 1. In Fig. 3 left, a resistance welding head 2 with the welding electrode 4, which is elastically gela ^¬ siege with the aid of a spring 8 and a drive 11, shown schematically.

In order to use the welding head 2 for a riveting operation, for example, as shown at the top right in FIG. 3, the electrode 4 is exchanged for an electrode 24 which on the workpiece side comprises a recess or trough 26. The trough 26 serves as Nietkopfsetzer in the riveting process. That is, the Recess or trough 26 has the shape of the later Nietkopfes.

Alternatively, the welding electrode 4 can also be provided with an adapter piece 23, which has a corresponding depression or recess 26. The adapter piece 23 is then attached to the electrode 4, screwed or fastened with other known ^¬ th means. For example, the adapter piece 23 has the same electrical characteristics as the electrode 4.

As shown in FIG. 2 using the example of the welding head 2, replacement or replacement of the electrode (s) is easy to accomplish. 4 now shows the connecting device 1, in which the two welding electrodes are exchanged for electrodes 24, 25, which have corresponding hollows 26, 27. It can also be said that the electrodes 24, 25 are Nietkopfsetzer. Like the customary welding electrodes 4, 5 (see Fig. 1), they are supported by means of resilient elements 8, 9.

FIG. 4 further shows that the workpieces 28, 29 to be joined each comprise an opening 31, 32 and are inserted into a workpiece holder 30 of a holder 10. When riveting essentially flat or sheet-like materials, such as bi- or Trimetallstre- fen, connected by means of a rivet to each other. The holding ^device 10 for the workpieces 28, 29 is also spring-mounted. For this purpose, a mounting plate 35, which can play, be a mounting table on ^¬, provided that includes a plurality of pins, for example three or four pins, which are not shown here. The pins 33 are each surrounded by a spring element 34, such as a spiral spring, and allow spring-mounted bearing of the holding device 10 with the workpieces 28, 29. For example, the holding device 10 is made of aluminum. To the two workpieces 28, 29 to nietend ver ^¬ bind to each other, a cylindrical connecting member into the coaxially arranged holes or openings 31, used 32nd 5, a detail of the connecting device 1 is indicated. It can be seen in the detail ^{display ¬} ment, the two workpieces 28, 29, whose openings are arranged coaxially along the effective axis 18 of the connecting device. Furthermore, one recognizes the connecting element 36, which consists of a plastically deformable material and is cylindrical in the exemplary embodiment. Preference ^¬ wise, the connecting element 36 and the rivet ge ^¬ know positive connection with the holes in the workpieces 28, 29. There are now the two electrodes, which are designed as Nietkopfsetzer 24, 25, above and below the connec ^¬ tion element 36th disposed. During the riveting operation, in particular ^¬ sondere during hot rivets, is carried out a movement of the electrodes 24, hereinafter called rivet applier 25 in the direction of the connecting element 36 along the axis of action 18th

FIG. 6 shows an operating situation of the connecting device 1 during hot or hot riveting. The control ^device 13 controls the drive devices 11, 12 via suitable control signals CT such that they initially travel in the direction of the joint. The two Nietsetzer 24, 25 thus press on the connecting element 36. The Steuerein ^¬ direction 13 causes by not shown here current sources, that a heating current 37 between the electrodes or Nietsetzern 24, 25 flows through the connecting element 36.

Preferably, the connecting element 36 has a material wel ^¬ ches has a higher electrical resistance than the Elect roden ^¬ or rivet 24, 25. In this respect, the connecting member is heated and expands there due to the heat supply from. The hot rivet or the hot connecting element 36 has particularly good hole life characteristics, so that in principle not completely round or symmetrical openings in the workpieces 28, 29 can be present. According to some aspects of the method, there is an oscillating hot riveting, whereby a simultaneous oscillating introduction of force onto the heated rivet or the hot connecting element 36 occurs from above and below. This is done by control with the aid of the control device 13 and the example pneumatic actuators 11, 12 for the welding ^¬ or rivet heads 2, 3. With the help of the elastic bearing 8, 9 both the welding or rivet heads 24, 25 as well as the factory - Piece carrier 10 is a particularly homogeneous and gleichmä ^¬ tiger force entry to the riveting. As a result, a ho ^¬ mogeneous and high process quality of the rivet is achieved. Through the interaction of the heat supply by the electric current 37 and the oscillating movements and thus a force of the electrodes or rivet on the connecting member 36, a deformation of the hot Verbin ^¬-making elements 36 takes place.

FIG. 7 shows a variant of the riveting method for connecting three flat workpieces with holes. Fig. 7 shows a trimetal strip 28, 29, 38, wherein the individual sheets 28, 29, 38 are connected by a rivet. It can be seen from above acting Nietsetzer 24, which is an electrode of the welding head, and the bottom acting rivet 25, which is another electrode of the

Welding head or another welding head represents. The arrows 16, 17 indicate the movement and force of the welding heads. Furthermore, the sprung mounting of the ^electrodes or rivet heads 24, 25 is indicated.

As a result of the current and the mechanical action, the initially cylindrical connecting element 36 is deformed in the form of a rivet, as shown in FIG. 7. ^This results in a rivet shank 39, which is closed off at the top and bottom by a rivet head 40, 41. Since the material of the connecting element is initially stretched in the hot ^¬ rivets or hot riveting, the rivet head shrinks slightly on cooling, and provides a particularly tight seal and a Connection of the elements or the workpieces 28, 29, 38 with ^¬ each other. Due to the shrinkage of the rivet shank results in an additional power friction. In this respect, the proposed method and the illustrated connection device, which allows a combination of riveting processes and welding processes, allow a versatile use thereof in production lines or assembly tables. The result is a multiple use of the resource resistance welding head, so that no additional Fü ^¬ or connecting stations must be kept in the assembly operation. It is sufficient a simple replacement of the welding electrodes or a fitting with adapter pieces of the electrodes of the resistance welding head.

When Nietbetrieb the current is adjusted by the rivet or fastener such that heating of the mate rials ^¬ of the connecting element takes place, but no welding or melting of the workpieces. Insofar resistive head for more efficient production is achieved by the flexible use of the resource in various ^¬ which joining methods, namely hot riveting and resistance welding, in particular of small to medium-sized electromechanical components that must be assembled.

The indicated workpieces are usually semi-finished parts, which are further processed at various assembly stations. Overall, an improved joining station in the manner of the connecting device, as presented, and by the presented Verbindungsver ^¬ drive an expanded and improved use of conventional WiderwandsschweißStationen.

Although the invention in detail by the preferred execution illustrated insurance for closer and described, the invention is not limited ^¬ by the disclosed examples and other variations can by a specialist from this can be derived without departing from the scope of the invention.

Claims

claims

A method of joining workpieces (28, 29) comprising:

- Providing a resistance welding head (2, 3) with at least two electrodes (3, 4);

Replacing at least one of the electrodes (3, 4) by a Nietkopfsetzer (24, 25) or providing at least one electrode (3, 4) with an adapter piece (23) comprising a Nietkopfsetzer;

Positioning two workpieces (28, 29) each having an opening (31, 32) between the electrodes (3, 4) or the rivet head setters (24, 25) of the resistance welding head (2) such that the openings (31, 32) are coaxial;

Inserting a connecting element (36) in the Öffnun ^¬ gene (31, 32); and

Riveting the workpieces (28, 29) with each other, wherein the connecting element (36) by means of the electrodes (3, 4) and / or the Nietkopfsetzers (24, 25) is deformed.

2. A method according to claim 1, further comprising: feeding an electric current (37) through the electrodes (3, 4) and / or the rivet head setter (24, 25) and the connection element (36) for heating the connection element (36). ,

3. The method of claim 1 or 2, wherein the electrodes (24, 25) relative to each other during the riveting along a by the connecting element (36) extending Wirkach- se (18) are moved in an oscillating manner.

4. The method according to any one of claims 1-3, wherein the workpieces (28, 29) are held sprung in a workpiece holder (30).

5. The method according to any one of claims 1-4, wherein at least three workpieces (28, 29, 38), which each have openings, are riveted to a connecting ^element (39).

6. The method according to any one of claims 1-5, wherein the two electrodes (3,4) are each replaced by a Nietkopfsetzer (24, 25) or in each case with an adapter piece (23), which comprises a Nietkopfsetzer provided and with the help of the two Nietkopfsetzer (24), the connecting element (36) is deformed.

7. The method according to any one of claims 1-6, wherein

the resistance welding head (2) is configured by means of an electric current (14) two further workpieces (6, 7) at a weld (15) to the melting to HEAT ^¬ zen.

8. The method of claim 7, further comprising:

Providing the resistance welding head (2) without Nietkopfsetzer;

Positioning the two further workpieces (6, 7) between the electrodes (4, 5); and

- Welding the two other workpieces (6, 7) with

Help the resistance welding head (2) at the weld (15) with each other.

9. The method according to any one of claims 1-8, wherein the

Welding the two electrodes (4, 5) are moved relative to the weld (15) and a constant force on the weld (15) is applied.

10. Connecting device (1) for connecting workpieces (6, 7, 28, 29, 38) together with a resistance welding head ^¬ (2), which at least two electrodes (3, 4, 24, 25), wherein the resistance welding head ( 2) is configured, with the aid of an electric current (14) to heat the workpieces (6, 7) at a weld (15) until melting, and wherein at least one electrode (24, 25) is designed as Nietkopfsetzer.

The connection device (1) according to claim 10, wherein the connection device (1) is arranged to perform a method according to any one of claims 1-9.

12. Connecting device (1) according to claim 10 or 11, further comprising a holding device (10) for the spring-loaded bearings of the workpieces (6, 7, 28, 29, 38).

13. Connecting device (1) according to any one of claims 10 - 12, further comprising a drive means (11, 12) for moving the electrodes (3, 4) and / or the Nietkopfsetzers (24, 25) on an active axis (18) relative to each other ,

14. Connecting device (1) according to any one of claims 10 - 12, wherein the electrodes (4, 5) and / or the Nietkopfsetzer

(24, 25) are resiliently mounted with respect to an axis of action (18).