EP3505270B1 - Setting unit for a punch rivet device, punch rivet device and method for manufacturing the same - Google Patents

Description

The present invention relates to a setting unit for a punch riveting device, a punch riveting device with such a setting unit, and a method for producing a setting unit or a punch riveting device.

State of the art

Joining processes, such as riveting processes, serve to connect at least two components (joining partners) that are particularly flat in a connection area. A punch riveting process is characterized, for example, by the fact that pre-punching of the components to be connected to one another is not necessary. Rather, a rivet as a joining element is pressed into the at least two components by means of a joining tool or a setting unit comprising a punch, it being possible to ensure that by means of a correspondingly shaped counterholder, for example in the form of a die, which interacts with the joining tool the rivet or the components are deformed in a certain way in order to produce a non-positive and positive connection between the components.

Furthermore, for example EP 2 318 161 B1 a so-called ultrasonic self-piercing riveting method is known in which a vibration generator, such as an ultrasonic generator, is used to set one or more components vibrating when the components are connected. This oscillation reduces, for example, the force to be used to press in the rivet. From the DE 10 2014 224 600 A1 which forms the basis for the preamble of claims 1 and 12, and the EP 3 120 951 A1 Ultrasonic punch riveting devices are known in which a booster is used to amplify vibration amplitudes for a sonotrode attached to it.

Disclosure of the invention

According to the invention, a setting unit, a punch riveting device, a method for connecting components and a method for producing a setting unit or a Self-piercing riveting device proposed with the features of the independent claims. Advantageous configurations are the subject of the subclaims and the description below.

The invention is based on a setting unit for a self-piercing riveting device, in which setting unit a rivet can be inserted, and which includes a vibration system comprising an (electromechanical) vibration converter which can be connected to an (electrical) vibration generator, a booster (amplitude amplifier) and a sonotrode as well as a Stamp, by means of which (usually using a suitable drive) the rivet can be subjected to force in one joining direction and can be introduced into at least two components during a riveting process. The oscillating system is held in a housing unit and in particular, at least partially, is also surrounded by it. In such a vibration system, the booster is typically provided between the vibration converter (for example in the form of a piezo converter) and the sonotrode.

With such setting units or when they are used in a punch riveting device, vibrations can be generated by the vibration system and coupled into the rivet via the punch. For this purpose, the vibration converter is connected to a vibration generator, for example an ultrasonic generator (usually in the form of a function generator). In this way, not only is the force required to press in the rivet reduced, but the vibrations can also improve the rivet connection itself, for example by means of an improved form fit or undercut, which leads to an improved joining point formation.

The three components vibration converter, booster and sonotrode should be firmly connected to one another. This can be done, for example, by means of a threaded pin, once between the vibration converter and booster and once between the booster and sonotrode. The tightening torques required for this are typically precisely defined in order to ensure proper function, i.e. transmission and amplification of the vibration, and the longest possible service life.

In addition, it should be ensured that the coupling surfaces are absolutely flat and clean. The surfaces should then be lightly moistened with oil before assembly.

However, this leads to a high production or assembly effort, especially when such components of the oscillating system are subsequently exchanged or the entire oscillating system is exchanged. Even when the components are exchanged, the individual work steps must be observed so that the oscillating system can oscillate at the frequency generated by the generator.

A force range for ultrasonic self-piercing riveting, i.e. a possible range in which the forces that occur can lie, can be up to 50 kN depending on the material combination. With these forces there is the possibility or the risk that the sonotrode experiences an offset due to transverse forces, which in extreme cases can also lead to damage and breakage of the sonotrode.

According to the invention it is now provided that the booster and the sonotrode are designed as one component, i.e. are made in one piece and made of one material. Steel, preferably hardened steel, is particularly suitable as a material. This eliminates the disadvantages mentioned above and which have occurred up to now, at least for the interface between booster and sonotrode, since a connection no longer has to be established here.

When used in series production, the oscillating systems or ultrasonic oscillating systems usually have to be exchanged regularly, as already mentioned, or at least the sonotrode has to be exchanged for rework. The effort required for this can be significantly reduced with the proposed, combined booster sonotrode. A minimization of possible sources of error is also achieved. When changing the vibration system, the combined booster sonotrode only needs to be screwed or fastened to the vibration converter.

Another advantage is that this one-piece sonotrode is manufactured or manufactured from one piece (ie from one material), which also reduces the effort involved in the initial manufacture of the booster and sonotrode - or then the combined booster-sonotrode. In a conventional, two-part system, however, the sonotrode and booster usually consist of different materials. This results in different length tolerances when the components are changed, which in extreme cases can be several millimeters. With the proposed one-piece solution, however, this length tolerance can be reduced to a few tenths of a millimeter.

The vibration system is expediently mounted via the booster in a first section of the housing unit, in particular by means of a bearing means that engages at least essentially in a vibration node of the booster (preferably in or as precisely as possible in the vibration node), in particular a clamping ring, ie a non-positive surrounding the booster ( = pinching) ring. It is particularly preferred that the oscillating system is fixedly mounted in the first section of the housing unit via the booster, i.e. that point of the oscillating system with which it rests on the housing unit or the bearing means cannot move in any direction relative to the housing unit (fixed bearing). Effective power transmission can thus be achieved from a drive of a punch riveting device to the oscillating system and via it to the rivet.

It is also particularly preferred if the oscillating system is mounted via the sonotrode in a second section of the housing unit, specifically in addition to the aforementioned mounting in the first section. The oscillation system is or will be supported in the second section of the housing unit by means of a bearing means that engages in an area of a oscillation node of the sonotrode, in particular a slide bearing, in particular loosely (e.g. slidingly), i.e. that point of the oscillation system with which it rests on the housing unit or the bearing means, can only move in the joining direction relative to the housing unit (floating bearing). Effective stability against transverse forces can thus be achieved.

In this way, the transverse deflection of the sonotrode (or the combined booster sonotrode) can be reduced particularly well with the typically very high forces. As mentioned, this additional mounting is expediently also arranged in the area of a vibration node of the sonotrode. Such an area is understood to mean that an exact mounting in the vibration node is typically not possible, since the sonotrode can easily move up and down at the level of the second area in the joining direction, especially with a fixed mounting in the mentioned first area. A plastic plain bearing, for example, can be used for the second bearing or bearing point. Such plain bearings consist, for example, of a base polymer with additions of glass fibers, various filling materials and solid lubricants.

Such a mounting in a vibration node of the sonotrode also has the advantage that no, or at least almost no longitudinal vibration amplitudes occur at this point, and the load on the sliding bearing is therefore very low. Due to the double storage, the sonotrode is also better protected against damage and breakage, which results in a longer service life.

It is particularly preferred if the booster and the sonotrode or the component forming them are designed as a lambda sonotrode. A lambda sonotrode is to be understood as meaning that the length of the combined booster sonotrode corresponds exactly or at least as precisely as possible to a wavelength of the vibrations in question. A particularly effective transmission of the vibrations is possible with a lambda sonotrode.

It should be noted here that, in theory, the booster and the sonotrode each have half a wavelength or half a lambda, but due to the one-piece design of the booster and sonotrode, such a distinction is no longer necessary or sometimes no longer desired. It is possible, however, that different areas of the combined booster sonotrode can be distinguished on the basis of their shape or diameter.

The stamp (of the setting unit) is preferably designed as part of the sonotrode. In other words, the sonotrode is also used as a stamp so that the sonotrode is brought into direct contact with the rivet. A separate stamp is therefore not necessary.

Alternatively, however, it is preferred if the stamp is designed as a component separate from the sonotrode, and in particular is then also arranged and optionally held in the setting unit in such a way that it is in operative connection with the sonotrode or can be brought. An additional component is required here, but the accessibility of the setting unit to the components to be joined can sometimes be significantly increased by a typically thin punch, since the sonotrode is typically relatively thick or has a large diameter, but at most a short, thin tip.

The invention also relates to a punch riveting device for connecting at least two components by means of a rivet, in which a setting unit according to the invention and a counter holder are arranged in such a way that the at least two components are positioned between the setting unit, there in particular the punch, while the rivet is being pressed in by means of the setting unit. and the counter holder can be arranged, and with a drive by means of which the punch and above the rivet can be acted upon with the force (in the joining direction).

The invention also relates to a method for manufacturing a setting unit for a punch riveting device or for manufacturing a punch riveting device with a) a setting unit, into which setting unit a rivet can be or should be introduced and which has a vibration system comprising a vibration converter which can be connected to a vibration generator , a booster and a sonotrode, and a stamp, by means of which the rivet can be acted upon with force in one joining direction and can be introduced into at least two components during a riveting process, and c) a housing unit for the oscillating system. Here, a component that (at the same time) forms the booster and the sonotrode is used for the oscillating system or is introduced into the oscillating system.

This can take place in particular during an initial production of the setting unit or punch riveting device, but also as part of maintenance in which the oscillating system or at least booster and sonotrode are replaced. In particular, previous two-part systems for booster and sonotrode can also be replaced in this way by a component proposed within the scope of the invention, which (at the same time) forms booster and sonotrode.

A setting unit according to the invention or a punch riveting device according to the invention is expediently used or manufactured in the method. With regard to the advantages and further refinements of the punch riveting device and the method, reference is made at this point to the above statements on the setting unit in order to avoid repetition, which apply here accordingly.

Further advantages and configurations of the invention emerge from the description and the accompanying drawing.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the present invention.

The invention is shown schematically in the drawing using an exemplary embodiment and is described in detail below with reference to the drawing.

Figure description

Figure 1

shows schematically a punch riveting device according to the invention in a preferred embodiment.

Figures 2a and 2b

show vibration systems of a setting unit not according to the invention and a setting unit according to the invention in a preferred embodiment in comparison.

Figure 3

shows schematically a production plant with a punch riveting device according to the invention.

Detailed description of the drawing

In Figure 1 a punch riveting device 10 according to the invention is shown schematically in a preferred embodiment, here as an ultrasonic punch riveting device which can also be used for a method according to the invention. The punch riveting device 10 has a frame 60, which is preferably in the form of a C-frame or C-bracket, on which the individual components of a punch riveting device can be arranged in order to be able to assume the desired position relative to one another.

Via the frame 60, the punch riveting device 10 can, for example, be attached to an arm for movement in space. For this purpose, two possible flange points 61 on the frame 60 are shown as an example, namely at the top right of the frame and on the side in the middle or lower area on the right. It goes without saying that one of these flange points is sufficient, but there can also be several of them so that a desired one can be selected when attaching.

The punch riveting device 10 has a joining tool or a setting unit 70, which in turn has an oscillating system 39. The oscillation system 39 here comprises a sonotrode 32 which is operatively connected to an electromechanical oscillation converter 30 via an amplitude amplifier 31 (so-called booster). The vibration converter 30 is in turn connected to a vibration generator 35, here an ultrasonic generator (in the sense of a signal generator), so that the vibration system 39 can be excited to vibrate. The oscillating system 39 is movably arranged in the longitudinal direction, which here corresponds to the joining direction R. The sonotrode 32 and the booster or amplitude amplifier 31 are in this case designed as one component or in one piece, as will be explained in more detail later.

Furthermore, a housing unit 40 is provided in which the oscillating system 39 is held and which is fastened to a drive 50. While the oscillating system is mounted in a first or upper section of the housing unit 40 via the booster 31, in particular by means of a clamping ring 41, the oscillating system is mounted in a second or lower section of the housing unit 40 via the sonotrode 32, in particular sliding by means of a plain bearing 42

A flange 64 is attached to the housing unit 40, via which the housing unit and thus the oscillating system 39 are connected to the frame 60 such that they can be moved and guided in the joining direction via a guide rail 65.

In particular, ultrasonic vibrations with an amplitude (distance between the maximum positive and negative amplitude of an oscillation) between 10 μm and 110 μm (corresponds to an amplitude of 5 μm to 55 μm) and a frequency between 15 kHz and 35 kHz or possibly also higher generated. The ultrasonic generator 35 as a vibration generator can be connected to a computing unit 95 and controlled by it.

Furthermore, the oscillating system 39 comprises a stamp 33, for example - like the sonotrode 32 at its free end (in the figure below) - with a round cross section. The punch 33 is designed here as a separate component from the sonotrode 32, i.e. it is not in one piece with the sonotrode 32 or the sonotrode does not assume the function of the punch. However, the stamp is held on the sonotrode, for example magnetically.

The punch 33 is per se a loose component and is mounted within a component 16, which also serves as a guide for the punch 33, and can be guided in the joining direction R. In addition, the component 16 serves as a hold-down device that can be pressed against the components 11, 12.

In addition, in this way the punch 33 can be moved together with the sonotrode 32 upwards or away from the components 11, 12. For this purpose, the drive 50 is coupled to the oscillating system 39, the drive not only serving to push one in of the rivet 20 to apply the force F required in the two components 11, 12, but also to move the oscillating system 39 away again. The drive 50 can be controlled, for example, by means of the computing unit 95.

The drive 50 can be, for example, a drive with a ball, roller or planetary screw drive or the like, which is suitable for applying a force F for pressing a rivet 20 as a joining element into the components 11, 12.

A counter holder 18 in the form of a die is arranged on the side of the two components 11, 12 opposite the setting unit 70. The setting unit 70 is arranged to be movable in the vertical direction and is movable relative to the die 18. The setting unit or the holding-down device 16 and the die 18 serve to clamp or compress the two components 11, 12 between the setting unit 70 and the die 18 during processing by the punch 33. A spring element 48 is used here to apply a pressure force to the components.

The rivet 20, here by way of example a semi-tubular rivet, preferably consists of a material that is harder than the materials of the two components 11, 12, at least in the area of a rivet shank. The flat upper side of the rivet facing away from the component 11 is arranged in operative connection with the punch 33, which rests flat against the upper side of the rivet 20.

Furthermore, a feed unit 90 with a profile hose is attached to the setting unit 70, in particular in the area of the hold-down device 16, which is used to feed the rivets. Rivets can be individually inserted into the setting unit 70 via the profile tube if it is not in contact with the components, so that a new rivet is available for each new riveting process.

In Figures 2a and 2b oscillating systems of a setting unit not according to the invention and a setting unit according to the invention are shown in a preferred embodiment in comparison. In Figure 2a an oscillating system 39 'of a setting unit not according to the invention is shown in FIG Figure 2b on the other hand, an oscillating system 39 of a setting unit according to the invention in a preferred embodiment, as shown for example in FIG Figure 1 is shown. It should be noted that in both cases the vibration converter - as it is for example in Figure 1 is designated by 30 - is not shown.

On the booster 31 there is - in both cases - an interface 43 for the clamping ring, as shown, for example, in FIG Figure 1 is shown, provided. In the installed state, the clamping ring surrounds this interface in a particularly non-positive manner and can thus hold the booster on the housing unit.

While the oscillating system 39 'in Figure 2a the booster 31 and the sonotrode 32 are two separate and then joined together, for example screwed, components, the booster 31 and the sonotrode 32 in the oscillating system 39 in FIG Figure 2b executed as one component and thus in one piece and from one material.

The advantage of the 39 in Figure 2b Apart from the unnecessary connection of two individual components, the booster and sonotrode do not each have to be half a wavelength long or have to be designed for it, but that overall only the combined component has to be a wavelength λ long, if it is a lambda sonotrode should act. This simplifies design and manufacture. For further advantages of such a combined booster sonotrode, reference is made at this point to the statements made above.

Furthermore, in Figure 2b an amplitude A of a longitudinal oscillation which forms in the booster or the sonotrode or the entire oscillation system is plotted. It can be seen here that in the combined booster sonotrode or the lambda sonotrode, two vibration nodes, ie points or areas with no or almost no amplitude, are formed, once in the booster and once in the sonotrode. While the interface 43 for the clamping ring is provided in the vibration account of the booster, the area 44 in which the vibration node of the sonotrode is located is provided for mounting on the aforementioned slide bearing.

In Figure 3 a production system 100 with a punch riveting device 10 is shown in a simplified and schematic manner in a preferred embodiment as an example of a use of the punch riveting device. The production plant can be, for example, an industrial robot, for example for an automobile body shop.

The production plant 100 has a support structure 3 arranged on a floor and two movable arms 4 and 5 arranged thereon, connected to one another.

At the end of the arm 5 is an ultrasonic self-piercing riveting device 10, such as that shown in FIG Figure 1 is shown in more detail, arranged.

Claims (12)

1. Setting unit (70) for a punch riveting device (10), into which setting unit (70) a rivet (20) is introducible, having a vibrating system (39) comprising a vibration converter (30) that is connectable to a vibration generator (35), a booster (31) and a sonotrode (32), and having a punch (33) by means of which the rivet (20) is able to be subjected to a force (F) in a joining direction and is introducible into at least two components (11, 12) during a riveting operation, and having a housing unit (40) for the vibrating system (39),
   characterized in that the booster (31) and the sonotrode (32) are configured as an integral component produced from one piece.
2. Setting unit (70) according to Claim 1, wherein the vibrating system (39) is mounted in a first portion of the housing unit (40) via the booster (31).
3. Setting unit (70) according to Claim 2, wherein the vibrating system (39) is mounted in the first portion of the housing unit (40) by means of a bearing means (41), in particular a clamping ring, acting at least substantially in a vibration node of the booster (31).
4. Setting unit (70) according to Claim 2 or 3, wherein the vibrating system (39) is mounted fixedly in the first portion of the housing unit (40) via the booster (31).
5. Setting unit (70) according to one of the preceding claims, wherein the vibrating system (39) is mounted in a second portion of the housing unit (40) via the sonotrode (32).
6. Setting unit (70) according to Claim 5, wherein the vibrating system (39) is mounted in the second portion of the housing unit (40) by means of a bearing means (42), in particular a plain bearing, acting in a region of a vibration node of the sonotrode (32).
7. Setting unit (70) according to Claim 5 or 6, wherein the vibrating system (39) is mounted loosely in the second portion of the housing unit (40) via the sonotrode (32) .
8. Setting unit (70) according to one of the preceding claims, wherein the booster (31) and the sonotrode (32) are configured as a lambda sonotrode.
9. Setting unit (70) according to one of the preceding claims, wherein the punch is configured as part of the sonotrode (32).
10. Setting unit (70) according to one of Claims 1 to 8, wherein the punch (33) is configured as a component separate from the sonotrode (32) and in particular is arranged in the setting unit (70) such that it is operatively connected or able to be operatively connected to the sonotrode (32).
11. Punch riveting device (10) for connecting at least two components (11, 12) by means of a rivet (20), in which a setting unit (70) according to one of the preceding claims and a dolly (18) are arranged such that the at least two components (11, 12) are arrangeable between the setting unit (70) and the dolly (18) while the rivet (20) is being pushed in by means of the setting unit (70), and
    having a drive (50), by means of which the punch (33) and, via the latter, the rivet (20) are able to be subjected to a force (F).
12. Method for producing a setting unit (70) for a punch riveting device (10) or for producing a punch riveting device (10) having a setting unit (70),
    into which setting unit (70) a rivet (20) is introducible and which has

    a) a vibrating system (39) comprising

    - a vibration converter (30) that is connectable to a vibration generator (35),

    - a booster (31) and a sonotrode (32), and

    - a punch (33) by means of which the rivet (20) is able to be subjected to a force (F) in a joining direction and is introducible into at least two components (11, 12) during a riveting operation, and

    b) a housing unit (40) for the vibrating system (39),

    characterized in that an integral component, produced from one piece, that forms the booster (31) and the sonotrode (32) is used for the vibrating system (39) or is introduced into the vibrating system (39).

Images