EP3120951A1 - Self-piercing rivet device and production device - Google Patents

Abstract

The invention relates to a punch rivet device (10 ') for connecting at least two components (11, 12), with a punch (15), a counter-holder (18), a hold-down (16') and a vibration generator (30), wherein the punch ( 15), the hold-down device and the counter-holder (18) are arranged relative to one another such that the at least two components (11, 12) between the punch (15) and the counter-holder (18) and at the same time between the hold-down (16 ') and the counter-holder (18) can be arranged, wherein the punch (15) and the vibration generator (30) are coupled together and form a vibration system (39), a drive (50) is provided, to which the punch (15) and the hold-down (16 '; ) are coupled in such a way that by means of the drive (50) a force (F) can be exerted on the punch (15) and on the hold-down device (16 ') in the direction of the components (11, 12), wherein the hold-down device (16') is coupled to the oscillating system (39), a vibration amplitude (A) of the blank holder (16 ' ) in the contact region with one of the components most 25%, in particular at most 10%, a vibration amplitude (A) of the punch (15) in the contact region with a rivet (20), and a manufacturing device with a punch riveting (10 ').

Description

The present invention relates to a punch riveting apparatus for connecting at least two components and to a production apparatus having such a punch riveting apparatus.

State of the art

Methods and devices for punch riveting serve for connecting at least two in a connection region in particular flat trained components (joint partners). A punch riveting method is characterized in that a pre-punching of the components to be joined together is not required. Rather, a rivet is pressed by means of a punch or a punch tool in the at least two components, being ensured by a correspondingly shaped counter-holder, for example. In the form of a die, which cooperates with the punch tool, that the rivet in a certain way deformed within the components to be joined together to produce a positive and positive connection between the components while avoiding penetration of the component facing away from the rivet.

Furthermore, for example, from the EP 2 318 161 B1 or the DE 10 2014 203 357 A1 so-called ultrasonic punch riveting methods or devices are known in which a vibration generator, such as. An ultrasonic generator is used to enable one or more components in the connection of the components in vibration. By this vibration, for example, the expended force is reduced to push the rivet.

Disclosure of the invention

According to the invention, a punch riveting device and a production device with the features of the independent patent claims are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

Advantages of the invention

A punch riveting device according to the invention serves for connecting at least two components and has a punch, a counter-holder, a holding-down device and a vibration generator. In this case, the punch, the hold-down and the counter-holder are arranged to each other such that the at least two components between the punch and the counter-holder and at the same time between the hold-down and the counter-holder can be arranged. The punch and the oscillator are coupled together and form a vibration system and there is provided a drive to which the punch and the hold-down are coupled so that by means of the drive, a force on the punch and on the hold-down in the direction of the components is exercisable. In this case, the holding-down device is coupled to the oscillating system in such a way that an oscillation amplitude of the holding-down device in the area of contact with one of the components is at most 25%, in particular at most 10%, of a vibration amplitude of the stamp in the contact area with a rivet. In other words, the holding-down device is thus coupled to the oscillating system in such a way that only a minimum, preferably no, oscillation can be transmitted from the oscillating system to the holding-down device. Preferably, the vibration amplitude of the blank holder in the contact area with one of the components is 0% (i.e., node) of the vibration amplitude of the punch in the contact area with the rivet, and no vibration is transmittable from the vibrating system to the blank holder. As a rivet, both a so-called semi-tubular rivet and a so-called solid rivet can be used.

In conventional punch riveting without vibration generator can be provided in a simple manner, a drive which can exert a force on the punch for pressing a rivet into the components and a force on the hold-down for pressing the components to the anvil at the same time. In a punch riveter with vibrator, in which during the depression of the rivet of the stamp in Oscillation is offset, in this case also the hold-down can be set in vibration, whereby the desired pressing force is reduced by the hold-down on the components. This can lead to poor rivet results or reduce the effect of vibration coupling or even completely hinder. While separate drives can be provided for the solution of this problem for the punch and the hold-down, a punch riveting device according to the invention with only one drive is required. This is possible because the hold-down is suitably coupled to the vibrating system formed by the vibrator and the punch, which causes the punch to vibrate as desired, but not the hold-down. In this way, a punch riveting device can be provided with only one drive, which is therefore simple and inexpensive.

Preferably, the hold-down is in a region of the vibration system in which a vibration amplitude of the vibration system at most 10%, in particular at most 5%, the vibration amplitude of the punch in the contact region with the rivet, coupled to the vibrating system. In other words, the hold-down device is coupled to the vibration system in a region of the vibration system in which an oscillation of the vibration system has the lowest possible amplitude. The oscillation amplitude of the oscillating system in this area is preferably 0% (ie vibration node) of the oscillation amplitude of the stamp in the area of contact with the rivet. As a rule, such a vibration system furthermore has a booster and / or a sonotrode, in particular also only a sonotrode, via which the ram is coupled to the vibration generator. In particular, the stamp can also be designed as a part of the sonotrode. A vibration is generated by the vibration generator and via the booster, the amplitude of the vibration is translated. Depending on the geometric design, the amplitude can be reduced, constantly transmitted, but usually translated and thus increased. Like the booster, the sonotrode forms a resonator, where the amplitude is usually further increased. Overall, this forms a standing longitudinal vibration in the vibrating system. This standing oscillation thus also has points or areas in which the amplitude is zero or at least almost zero. Now, if the hold-down is coupled in such an area of the vibration system to the vibration system, no or almost no vibration is transmitted to the hold-down. Thus, a uniform force can be exerted on the components. It It is understood that the corresponding areas depend on the design of the vibration system.

Advantageously, a holding device is provided, which is fastened to the drive, and to which the oscillating system is attached. In particular, the holding device surrounds the vibrator at least partially. By such a holding device is a particularly simple and space-saving arrangement of the vibration system in the punch riveting possible. In particular, in this way, the oscillating system can be largely decoupled from the drive with respect to vibration transmissions.

It is advantageous if the holding-down device is fastened to the holding device separately from the oscillating system. Thus, both the oscillating system and the hold-down to the holding device and the holding device are attached to the drive. Thus, a power transmission from the drive to the punch and the hold-down is possible. However, no direct contact between the oscillating system and hold-down is given by the separate attachment of the oscillating system and hold-down on the fixture, but there is only an indirect contact on the holding device, which can also be kept low with a suitable design of the holding device. In this way, a vibration transmission from the vibration system to the holddown is largely avoided. If the oscillating system is also fastened to the holding device in a region of the oscillating system in which a vibration of the oscillating system has the lowest possible, in particular no, amplitude, a vibration transmission to the holding-down device is further reduced. Alternatively or additionally, care must be taken that the vibration system is fastened near the vibration generator or remote from the punch on the holding device, since an amplitude is generally significantly lower than in the area of the punch.

Alternatively, it is preferred that the hold-down device is coupled to the oscillating system in a region of the stamp in which a vibration amplitude of the oscillating system has at most 10%, in particular at most 5%, of the oscillation amplitude of the stamp in the contact region of the rivet. In other words, the holding-down device is coupled to the oscillating system in a region of the stamp in which an oscillation of the oscillating system has the lowest possible amplitude. Preferably, the oscillation amplitude of the oscillating system in this range is 0% (ie Vibration node) of the vibration amplitude of the punch in the contact area with the rivet. This is possible since, as a rule, a region also occurs in the stamp in which the already mentioned stationary oscillation has no or at least almost no amplitude. If the hold-down is coupled here, the hold-down can be made very compact, since the punch is close to the components.

Preferably, the hold-down on a spring unit, via which it is coupled to the oscillating system. In this way, the relative movement between the punch and hold-down due to the lowering of the punch when pressing the rivet can be taken into account, while the force from the drive acts on the hold-down. In the case of a suitable coupling of the hold-down device to the holding device or to the stamp, the spring unit can have, for example, a cylindrical helical compression spring or disk springs or an elastomeric spring. It is also possible to provide a vibration-damping or sound-insulating coating, for example a suitable lacquer, on the hold-down device, in particular in a region where the hold-down device is coupled to the oscillating system or other components. This vibration of the blank can be reduced. By means of a spring stiffness or a spring constant, a hold-down force can be adapted during the indentation of the rivet. Taking into account the force applied by the drive, the spring constant can be suitably selected so that, for example, hold-down forces between 2 kN and 8 kN are obtained. In particular, during the course of the hold-down force during the indentation, it can also be taken into account that the spring constant runs, for example, linearly with a cylindrical helical compression spring, degressive with disc springs or progressively with pressure-loaded elastomer springs.

Advantageously, the spring unit has a damping material which is suitable for reducing an amplitude of the vibrations generated by the vibration generator to at least half. In particular, the spring unit may, for example, be an elastomeric spring, ie an elastic material which transmits the linear movement of the drive, but not the generally high-frequency oscillation generated by the oscillator. Instead of an elastomeric spring, only in addition to a conventional spring, a damping material, for example. An elastomer can be used.

It is advantageous if the vibration generator is designed as a sound generator, in particular as an ultrasonic generator, more particularly a piezo converter. This is a simple method for vibration generation.

Conveniently, the vibration system further comprises a booster and / or a sonotrode, via which the punch is coupled to the vibration generator. In particular, the stamp is formed as a part of the sonotrode. This is a common and easy to use arrangement for a vibration system for a punch riveter.

Conveniently, the punch riveting apparatus further comprises a frame having an interface for attachment of the punch riveting apparatus to a manufacturing apparatus such as an industrial robot. This allows a very simple assembly, for example. In the context of an exchange.

A production device according to the invention has a punch riveting device according to the invention.

To avoid repetition, reference is made to the above statements on the punch riveting apparatus according to the invention with regard to further advantages of a production apparatus according to the invention.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

The invention is illustrated schematically by means of exemplary embodiments in the drawing and will be described in detail below with reference to the drawing.

figure description

FIG. 1

shows simplified and schematically a manufacturing device according to the invention in a preferred embodiment.

FIGS. 2a to 2d

show a punch riveting apparatus at various stages of performing a punch riveting process.

FIG. 3

schematically shows a punch riveting without vibration generator.

FIGS. 4a and 4b

show schematically punch riveting according to the invention in various preferred embodiments.

Detailed description of the drawing

In FIG. 1 is simplified and schematically shown a manufacturing device 100 according to the invention in a preferred embodiment. The production device 100 may be, for example, an industrial robot in a production hall, for example for an automobile body shop.

In this case, the production device 100 has a carrier structure 3 arranged on a base and two arms 4 and 5 arranged thereon and connected to one another and movable. At the end of the arm 5, a punch rivet 10 'according to the invention is arranged, which in the FIGS. 3a to 3d will be described in more detail.

Furthermore, a computing unit 80 is shown, which is, for example, a control unit for the punch riveting apparatus 10 '. The arithmetic unit 80 may also be used as a control unit for the entire manufacturing facility, i. be provided in addition to the punch riveting especially for the control of the movable arms. Furthermore, display means 90, for example a display, are provided on which, for example, current operating parameters of the punch riveting apparatus can be displayed.

In the FIGS. 2a to 2d is schematically and simplifies a not punching riveting 10 according to the invention shown at different phases punch riveting. The Punch riveting device 10 has a punch 15, which for example has a round cross section.

The punch 15 is radially surrounded by a sleeve-shaped hold-down 16 and arranged movable relative to this in the longitudinal direction. In particular, the punch 15 is coupled to a drive, not shown here, for example a hydraulic or pneumatic drive, which serves to apply a force F required to press a rivet 20 into the two components 11, 12.

Also, the hold-down 16 is adapted to press against the surface of the die 15 facing member 11 with a hold-down force. For this purpose, for example, a separate drive can be provided. However, the hold-down can also be coupled to the drive of the punch 15, for example by means of a spring.

On the stamp 15 and the hold-down 16 opposite side of the two components 11, 12 a counter-acting die 18 is arranged. The die 18 is also in the direction of a longitudinal axis 19, in the direction of which also the punch 15 and the hold-16 are arranged movable, raised and lowered. The hold-down 16 and the die 18 serve to clamp or compress the two components 11, 12 between the hold-down 16 and the die 18 during processing by the punch 15. The die 18 has, on the side facing the component 12, a planar upper side 21, from which a trough-shaped or recess 22 extends. The Matrizenausnehmung can be flat, conical or spherical or a dome or. Have thorn in the middle of the recess.

The rivet 20, here by way of example a half-tubular rivet, preferably consists of a material that is harder than the materials of the two components 11, 12, at least in the region of the rivet shank 24. The flat top side facing away from the component 11 is arranged in operative connection with the ram 15. which rests flat on the upper side 26 of the rivet 20. Thus, the top 26 of the rivet is a contact point 27 between the rivet and the punch.

The punch 15 is operatively connected to a vibration generator 30 for generating vibrations. In particular, by means of the vibrator 30 ultrasonic vibrations with an amplitude (distance between the maximum positive and negative amplitude of a vibration) between 10 .mu.m and 110 .mu.m (corresponding to an amplitude of 5 .mu.m to 55 .mu.m) and a frequency between 15 kHz and 35 kHz or possibly generated higher.

These vibrations 15 are coupled by the vibrator 30 via the punch 15 in the rivet 20. The coupling-in direction of the vibrations of the vibration generator 30 can take place, for example, parallel to the longitudinal axis 19, that is to say parallel to the joining direction of the rivet 20 into the components 11, 12. The vibration generator 30 is connected to the computing unit 80, and can be controlled by the latter.

In the FIG. 2a Phase shown represents a beginning of the Stanznietverfahrens in which the rivet shank 24 comes into operative connection with the top of the component 11. In this case, the punch 15 is pressed with the force F against the stamp 15 facing member 11.

In an in FIG. 2b shown further phase, ie during the course of the riveting process and under support of the vibrations coupled into the components 11, 12, the rivet shank 24 initially cuts or punches into the component 11. In this case, the two components 11, 12 are plastically deformed, wherein the recess 22 facing the component 12 is pressed in the corresponding areas in the recess 22.

During the further movement path or the further downward movement of the rivet 20 according to the Figure 2c the projections or the rivet shank 24, in the region of the recesses 22, are spread outward, as a result of which the two components 11, 12 are securely connected to one another in the axial direction in a positive and non-positive manner.

It is essential that according to the Figure 2d , which shows the end position of the rivet 20, the rivet shank 24 does not protrude from the component 12 or does not completely penetrate it.

After the rivet 20 in the Figure 2d has reached the end position shown in which the top 26 of the rivet 20 at least approximately flush with the top of the component 11th closes, then the punch 15 is again moved by the components 11, 12 in the opposite direction upwards.

In FIG. 3 is shown schematically and simplified a punch rivet without vibrator. Compared to those in the FIGS. 2a to 2d shown punching riveting the coupling of the blank holder 16 is shown on the punch 15 here.

The punch 15 has a radial projection on the upper end shown here. In this radial projection, a spring unit 41, for example. In the form of a cylindrical helical compression spring, mounted, via which the hold-down 16 is coupled to the punch 15.

If a force F is now exerted on the punch 15 for impressing the rivet 20 via a suitable drive, then the force is simultaneously exerted on the hold-down 16, by means of which the components 11, 12 are pressed against the counter-holder or the die 18, wherein the spring unit 41 of the relative movement between the punch 15 and holddown 16 is taken into account.

It can be seen from the illustrated arrangement of punch and downholder that this arrangement is unsuitable for a punch riveter with a vibrator, since the oscillations would be transmitted not only to the punch but also to the downholder. The components 11, 12 would not be satisfactorily pressed against the counter-holder 18 with a swinging hold-down device.

In FIG. 4a Now, a punch rivet 10 'according to the invention is shown in a preferred embodiment. 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 are usually arranged in a punch riveting in order to take the desired position to each other. About the frame 60, the punch rivet 10 ', for example. At the in FIG. 1 be shown arm 3 attached. It is understood that even in the in the FIGS. 2a to 2d and 3 Punch riveting shown in the rule, such a frame may be present.

Furthermore, a drive 50 is shown, which may, for example, be a spindle drive or the like, which is suitable for applying a force F for pressing in the rivet 20 into the components 11, 12. On the drive 50, a holding device 35, for example. In the form of a frame or a frame attached. On the holding device 35 is a vibration system 39, which in the present case has a vibration generator 30, for example. An ultrasonic generator, a booster 31, a sonotrode 32 and a punch 15, respectively.

As can be seen from the figure, the oscillating system 39 is arranged or fastened to the holding device 35 approximately in the center of the booster 31, which has an upper, a wider and a lower, narrower part. It should be noted that the punch 15 may, for example, be part of the sonotrode 32, i. that both components can form a structural unit. Although the booster 31 is connected to the holder 35, the booster 31 in the region where it is connected to the holder 35 has no (i.e., vibration nodes) or only a small amplitude of vibration.

Furthermore, a hold-down 16 'is shown, which is coupled by means of a spring unit 41, for example. In the form of a cylindrical helical compression spring, to the holding device 35. The hold-down 16 'is thus coupled to the holding device 35 separately from the oscillating system 39, i. the hold-down 16 'is only indirectly coupled to the oscillating system 39. An oscillation of the oscillating system 39 is not transmitted by this type of coupling or at least only slightly to the hold-down 16 '.

Furthermore, a diagram is shown on the right side of the figure, in which a curve of a vibration amplitude A of an oscillation forming in the vibration system 39 is shown above the position λ. It can be seen that the region at which the oscillating system 39 is coupled to the holding device 35 is a point of low oscillation amplitude. In addition, in this, in this case the upper region of the oscillating system 39, the oscillation amplitude is generally lower than in the lower region of the plunger 15. In this respect, a possibly still transferable oscillation hardly affects the downholder, since the oscillation amplitude would be very small.

In FIG. 4b a punch rivet 10 'according to the invention is shown in a further preferred embodiment. Opposite the in FIG. 4a shown punch riveting 10 'is the hold-down 16 'is not coupled to the holding device 35, but to the oscillating system 39 in the region of the punch 15 or the sonotrode 32.

It can be seen from the diagram on the right-hand side in the figure, in which a course of a vibration amplitude A of a vibration forming in the vibration system 39 is shown, above the position λ, that the hold-down 16 'is in one region by means of the spring unit 41 , here at the upper end of the punch 15, the oscillating system 39 is coupled, in which the oscillation amplitude is very low, preferably zero. In the present case, the spring unit 41 is attached to a component 42, which in turn is mounted in the relevant region of the punch 15.

Such a suitable region with little or no oscillation amplitude can be determined, for example, on the basis of the design of the oscillation system 39 or by means of tests. By such a coupling of the hold-down 16 'to the vibration system 39 can be achieved that no or at least almost no oscillations are transmitted from the oscillating system 39 to the hold-down 16'.

Claims (13)

A punch riveting apparatus (10 ') for connecting at least two components (11, 12), comprising a punch (15), a counter - holder (18), a hold - down (16') and a vibration generator (30), wherein the punch (15), Downholder and the counter-holder (18) are arranged to each other such that the at least two components (11, 12) between the punch (15) and the counter-holder (18) and at the same time between the hold-down (16 ') and the counter-holder (18) can be arranged are, wherein the punch (15) and the vibration generator (30) are coupled together and form a vibrating system (39), characterized in that a drive (50) is provided, to which the punch (15) and the hold-down (16 '; ) are coupled in such a way that by means of the drive (50) a force (F) can be exerted on the punch (15) and on the hold-down device (16 ') in the direction of the components (11, 12), wherein the hold-down device (16') is coupled to the vibration system (39) in such a way that a vibration amplitude (A) of the hold-down device S (16 ') in the contact region with one of the components highest 25%, in particular at most 10%, a vibration amplitude (A) of the punch (15) in the contact region with a rivet (20). Punch riveting apparatus (10 ') according to claim 1, wherein the hold-down device (16') in a region of the vibration system (39) in which a vibration amplitude (A) of the vibration system (39) at most 10%, in particular at most 5%, of the vibration amplitude (A ) of the punch (15) in the area of contact with the rivet (20) is coupled to the oscillating system (39). A punch riveting apparatus (10 ') according to claim 1 or 2, wherein a holding device (35) is provided which is fixed to the drive (50) and to which the oscillating system (39) is attached. A punch riveting apparatus (10 ') according to claim 3, wherein said holding device (35) at least partially surrounds said vibrator (30). A punch riveting apparatus (10 ') according to claim 3 or 4, wherein the hold-down (16') is fixed to the holder (35) separate from the vibrating system (39). Punch riveting apparatus (10 ') according to any one of claims 1 to 4, wherein the hold-down (16') in a region of the punch (15) in which a vibration amplitude (A) of the vibration system (39) at most 10%, in particular at most 5%, the oscillation amplitude (A) of the punch (15) in the contact area with the rivet (20) is coupled to the oscillating system (39). Punch riveting apparatus (10 ') according to one of the preceding claims, wherein the hold-down device (16') has a spring unit (41) via which it is coupled to the oscillating system (39). A punch riveting apparatus (10 ') according to claim 7, wherein the spring unit (41) comprises a damping material, in particular an elastomer, which is suitable for reducing an amplitude of the vibrations generated by the vibration generator to at least half. Punching riveting device (10 ') according to any one of the preceding claims, wherein the vibration generator (30) as a sound generator, in particular as an ultrasonic generator, further in particular as a piezo converter is formed. A punch riveting apparatus (10 ') according to any one of the preceding claims, wherein the oscillating system (39) further comprises a booster (31) and / or a sonotrode (32) via which the punch (15) is coupled to the vibrator (30). A punch riveting apparatus (10 ') according to claim 10, wherein the punch (15) is formed as a part of the sonotrode (32). A punch riveting apparatus (10 ') according to any one of the preceding claims, further comprising a frame (60) having an interface for mounting the punch riveting apparatus (10') to a manufacturing device (100). Manufacturing device (100) with a punch riveting device (10 ') according to one of the preceding claims.

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