EP3117925A1 - 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) and the counter-holder (18) are arranged in such a way that the at least two components (11, 12) between the punch (15) and the counter-holder (18) can be arranged, wherein the punch (15) by means of the vibration generator (30). is oscillatable, wherein the hold-down (16 ') at least partially surrounds the punch (15) and is arranged for pressing the at least two components (11, 12) against the counter-holder (18), wherein mutually facing surfaces (42, 43) of stamp (15) and hold-down (16 ') are spaced apart, so that the surfaces (42, 43) formed as a boundary of a gap (45), and a manufacturing device with a punch rivet device (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, for example, an ultrasonic generator is used to enable one or more components when connecting 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 and the counter-holder are arranged to each other such that the at least two components between the punch and the counter-holder can be arranged and the punch is set into vibration by means of the vibration generator. The hold-down surrounds the stamp at least partially and is adapted for pressing the at least two components to the counter-holder. In this case, mutually facing surfaces of the punch and hold-down are spaced apart, so that the surfaces are formed as a boundary of a gap. 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, the punch can be in contact with the outside of it with the inside of the blank holder surrounding it. When the punch is pressed with force to engage a rivet, the punch slides along the inside of the hold-down. Occurring frictional forces are negligible or at least acceptable. In a punch riveter with oscillator, however, the punch is set during the depression of the rivet in vibration, resulting in an additional, usually high-frequency, relative movement between the punch and the hold-down. The friction between punch and hold-down can lead, for example, to undesired signs of wear and / or cold welding. This can further result in a reduced tool life. In a punch riveting device according to the invention with a spacing between the mutually facing surfaces of punch and hold-down, however, a friction is significantly reduced or even prevented. The mentioned disadvantages such as wear or cold welding can thus be prevented, which thus leads to increased tool life, less maintenance and lower costs. Likewise, this is a so-called. Stick-slip effect, ie a change between static friction and sliding friction avoided, which leads to an unobstructed and thus more effective oscillatory movement of the punch.

Preferably, the gap is at least partially filled with a hydraulic fluid. In particular, the stamp may be hydrostatically supported in the hold-down device, and more particularly, a circuit for the hydraulic fluid may be provided. For example, a corresponding pump may be provided for the circuit. It is understood that for this purpose, the gap should be limited especially at the other boundary surfaces that are not covered by the surfaces of stamp and hold-down. This is, for example, possible by the hold-down has a corresponding projection in the direction of the punch. A resulting, possible friction between the projection on the hold-down and the punch is usually negligible. In particular, the projection may be formed of low friction material on the stamp. By such a hydrostatic bearing a particularly low-friction relative movement between the punch and hold-down is possible. In addition, such hydrostatic bearing also provides stability for the stamp, i. The punch can be guided in the hold-down. In the case of a circuit, in addition, the hydraulic fluid can be exchanged and thus heat dissipated. Thus, a cooling of the punch and the blank holder can be provided simultaneously.

Advantageously, the intermediate space is at least partially filled with a solid material, in particular with a low adhesion tendency, further in particular having plastic, ceramic and / or carbon. As a plastic, for example, polytetrafluoroethylene (PTFE) can be used here. The carbon may, for example, be present as a synthetic and / or natural diamond or diamond-like layer. The material allows a stable guidance for the punch in the hold-down. By a suitable choice of material, the friction can also be kept low, in particular less than this would be the case between punch and hold-down, which are usually made of steel.

Preferably, the solid material is attached to the stamp facing surface of the blank or on the down-facing surface of the punch and is in contact with the respective other surface. In this way, the material is allowed to remain in position during a riveting operation, while between the surface where the material is not secured and the material has a desired, low-friction contact.

Alternatively, it is preferred that the solid material is formed as an exchangeable element, in particular as a sleeve, which surrounds the stamp at least partially and is in contact with both surfaces. It is understood that the punch riveting apparatus should then be designed so that the element remains in position during a riveting operation. For example. Here, a projection may be formed on the element with which the element rests against the hold-down. Likewise, a projection may also be formed on the hold-down, on which the element rests. The ability to replace the element avoids a more expensive and costly replacement of the punch or blank if the material is worn. Such an element can be provided as a spare part. In addition to, for example, a PTFE sleeve can, for example, a ceramic sleeve, for example. Al ₂ O ₃ , ZrO ₂ , SiC or TiN, are used. It is also conceivable to use another wear-resistant, hard material which has been suitably treated on the surface, for example by grinding and / or mechanical and / or thermal polishing.

It is advantageous if introduction means are provided which are adapted to introduce a lubricant into the intermediate space. In this way, for example, a lubricating film between the mutually facing surfaces are formed, which leads to a significant reduction in friction. It is understood that in this case, the distance between the facing surfaces should be very small, but greater than zero. In this case, the introduction means can, for example, have one or more injection nozzles at a suitable point, which have a corresponding feed for the lubricant.

Expediently, the lubricant has a lubricant, in particular based on graphite, wax and / or oil, or a release agent, in particular on a ceramic and / or polymeric basis. These are lubricants for the effective reduction of friction, which are also easily introduced.

Preferably, the introduction means are further adapted to introduce the lubricant continuously or repeatedly, in particular at predetermined time intervals, in the intermediate space. Thus, a continuous sliding or lubricating film can be formed between the facing surfaces. In the case of, for example, viscous lubricants, such as those based on wax, a repeated introduction may be sufficient.

It is advantageous if the punch is replaceable directly or indirectly attached to the vibrator. In order for a stamp when this example shows signs of wear and / or if its functionality is reduced, be easily replaced by a new stamp. A stamp can be attached, for example, by screwing or plugging to the vibrator or a sonotrode coupled thereto.

Preferably, a positioning device for a rivet that can be used with the punch riveting device is provided on an inner side of the hold-down device. This makes it very easy to hold a rivet in place for and during a riveting operation. This is particularly useful when the hold-down is spaced from the punch, since the hold-down then, depending on the diameter of the rivet, often can provide no guidance for the rivet. It is understood that such a positioning device should then be mounted at an appropriate height in order to support the rivet for as long as possible during the depression of the rivet in the components can.

Advantageously, the positioning device has a, in particular by means of spring force, centering device. In this way, an optimal position of the rivet can be achieved, since it is known that the rivet is exactly in the center of the hold-down, while it is not visible from the outside.

It is advantageous if the vibration generator is designed as a sound generator, in particular as an ultrasound generator. This is a simple method for vibration generation.

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.

Figur 1

zeigt vereinfacht und schematisch eine erfindungsgemäße Fertigungseinrichtung in einer bevorzugten Ausführungsform.

Figuren 2a bis 2d

zeigen eine Stanznietvorrichtung bei verschiedenen Phasen der Durchführung eines Stanznietverfahrens.

Figuren 3a bis 3d

zeigen schematisch erfindungsgemäße Stanznietvorrichtungen in verschiedenen bevorzugten Ausführungsformen.

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.

FIGS. 3a to 3d

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 can also as Control unit for the entire manufacturing facility, ie, 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 a punch rivet 10 not according to the invention is shown at different stages of a punch riveting process. The punch riveting apparatus 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, for example, a trough-shaped or recess 22 extends.

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. Consequently For example, 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 vibration generator 30, ultrasonic vibrations having an amplitude (distance between maximum positive and negative amplitude of a vibration) between 10 μm and 110 μm (or an amplitude between 5 μm and 55 μm) and a frequency between 15 kHz and 35 kHz are generated.

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 (longitudinal) of the rivet 20 into the components 11, 12 or torsional (torsional vibration system). 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 come 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 rivet shank 24 is spread outward in the region of the recess 22, as a result of which the two components 11, 12 are positively and non-positively connected to one another in the axial direction.

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, in which the top 26 of the rivet 20 at least approximately flush with the top of the component 11, then the punch 15 is again moved by the components 11, 12 in the opposite direction upwards.

In FIG. 3a Now, a punch rivet 10 'according to the invention is shown in a preferred embodiment. The punch riveting device 10 'differs from that in the FIGS. 2a to 2d shown punch riveting 10 in that a stamp 15 facing surface 42, here the inside of the blank holder 16 'of a downholder 16' facing surface 43, here the outside, of the punch 15 is spaced. The two surfaces 42 and 43 thus form a boundary of a space 45 having a volume. In this way, a friction between the punch 15 and the hold-down 16 'is avoided.

Furthermore, springs 41 are shown, by means of which the hold-down 16 'is fastened to a holder 40. The holder 40, in turn, may be attached to the vibrator 30 or to a sonotrode (not shown) connected to the vibrator 30. About such a sonotrode, the punch 15 may be coupled to the vibrator 30. However, it is also conceivable that the holder 40 is directly connected to a holder of the entire punch rivet 10 '. By the springs 41, the hold-down 16 'is pressed against the components during an indentation of the rivet 20 into the components 11, 12, whereby the components are held in position.

Furthermore, a positioning device 55 is shown, which is arranged on the inside of the blank holder 16 'approximately at the level of the center of the rivet 20. The positioning device 55 may, for example, be a plurality of springs, which are arranged at a uniform distance in a circular manner on the inside of the hold-down 16 '. In this respect, it may, for example, be a centering device. For this purpose, for example, the springs can also be introduced into blind holes in the hold-down device.

In FIG. 3b a punch rivet 10 'according to the invention is shown in a further preferred embodiment. Opposite the in FIG. 3a In the embodiment shown, the gap 45 between the surfaces 42 and 43 is filled with a hydraulic fluid 50. At the top and bottom, suitable limitations for the hydraulic fluid 50, such as protrusions on the inside of the blank holder 16 ', may be provided. Furthermore, openings 60, for example. Holes, provided in the hold-down 16 ', via which the gap 45 to a hydraulic circuit, eg. With a corresponding pump, can be connected and via which thus the hydraulic fluid 50 can be pumped through the gap 45.

In Figure 3c a punch rivet 10 'according to the invention is shown in a further preferred embodiment. Opposite the in FIG. 3a In the embodiment shown, a solid material 51 is introduced into the intermediate space 45 between the surfaces 42 and 43. This material may, for example, be plastic, for example PTFE. Furthermore, the solid material 51 may be formed as an exchangeable element, for example a sleeve, which, as in FIG Figure 3c shown by means of a projection on the top of the hold-16 'rests.

However, it is also possible that the solid material is not formed as an exchangeable element, but as a coating on the surface 42 of the blank holder 16 'or on the surface 43 of the punch 15. A lead, as in Figure 3c shown is not necessary. The material may, for example, be glued to the relevant surface, pressed in a positive and / or positive fit or screwed by means of countersunk screws.

In 3d figure a punch rivet 10 'according to the invention is shown in a further preferred embodiment. Opposite the in FIG. 3a In the embodiment shown, insertion means 61 are provided at the upper end of the hold-down 16 '. These introduction means 61 may be, for example, nozzles or the like, which are introduced, for example, into a bore in the hold-down 16 '. However, it is also conceivable that such nozzles, for example. At the top of the blank holder 16 'are mounted.

By means of the introduction means 61, a lubricant can be introduced into the intermediate space 45 between the surfaces 42 and 43. It is understood that the Einbringmittel 61 for this purpose to a suitable supply of lubricant, for example. Via corresponding hoses, are connected. In a suitable embodiment, for example, continuously or at certain time intervals lubricant between the punch 15 and the hold-16 'are introduced, whereby a lubricant film in the space 45 is formed.

For completeness, it should be noted that the in FIG. 3a shown positioning device 55 also in the embodiments according to the Figures 3b to 3d can be used or may be present. Incidentally, a riveting operation by means of a punch riveting apparatus 10 'according to the invention, such as in various embodiments in the FIGS. 3a to 3d shown to proceed as in the FIGS. 2a to 2d is shown and described with reference to a conventional punch riveting apparatus 10.

Claims (14)

Punch riveting apparatus (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) 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) can be arranged, wherein the punch (15) by means of the vibration generator (30) is set into vibration wherein the hold-down (16 ') at least partially surrounds the punch (15) and is adapted for pressing the at least two components (11, 12) against the counter-holder (18), characterized in that mutually facing surfaces (42, 43) of Stamp (15) and hold-down (16 ') are spaced apart, so that the surfaces (42, 43) are formed as a boundary of a gap (45). A punch riveting apparatus (10 ') according to claim 1, wherein said gap (45) is at least partially filled with a hydraulic fluid (50). The punch riveting device (10 ') according to claim 2, wherein the punch (15) is hydrostatically supported in the hold-down device (16'), and wherein in particular a circuit for the hydraulic fluid (50) is provided. Punching riveting device (10 ') according to one of the preceding claims, wherein the intermediate space (45) is at least partially filled with a solid material (51), in particular with a low adhesion tendency, further plastic, ceramic and / or carbon, in particular. A punch riveting apparatus (10 ') according to claim 4, wherein the solid material (51) is located on the surface (52) of the blank holder (16') facing the punch (15) or on the surface (43) of the punch facing the blank holder (16 ') (15) is fixed and in contact with the other surface. A punch riveting apparatus (10 ') according to claim 4, wherein the solid material (51) is formed as an exchangeable element, in particular a sleeve, which at least partially surrounds the punch and is in contact with both surfaces. A punch riveting apparatus (10 ') according to any one of the preceding claims, wherein introducing means (61) are provided which are adapted to introduce a lubricant in the intermediate space (45). Punch riveting device (10 ') according to claim 7, wherein the lubricant comprises a lubricant, in particular graphite, wax and / or oil-based, or a release agent, in particular on a ceramic and / or polymeric basis. Punch riveting apparatus (10 ') according to claim 7 or 8, wherein the introduction means (61) are further adapted to introduce the lubricant continuously or repeatedly, in particular at predetermined time intervals, in the intermediate space (45). A punch riveting apparatus (10 ') according to any one of the preceding claims, wherein the punch (15) is replaceably mounted directly or indirectly on the vibrator (30). Punching and riveting apparatus (10 ') according to one of the preceding claims, wherein a positioning device (55) for a rivet (20) which can be used with the punch riveting apparatus (10) is provided on an inner side of the hold-down device (16'). Punching riveting device (10 ') according to claim 12, wherein the positioning device (55) has a, in particular by means of spring force, operating centering device. 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 is formed. Manufacturing device (100) with a punch riveting device (10 ') according to one of the preceding claims.

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