EP3381581B1 - Punch rivet device and method for operating 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, a production system with such a punch riveting device and a method for operating 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 that includes a punch, it being possible to ensure that the rivet or the rivet or the rivet can be secured by a correspondingly shaped counter-holder, for example in the form of a die, which interacts with the joining tool the components deform 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 process is known in which a vibration generator, such as an ultrasonic generator, is used to set one or more components vibrating when connecting the components. This oscillation reduces, for example, the force required to press in the rivet.

In the case of riveting processes, it is generally necessary for automated operation to ensure that the rivets are fed and, in particular, that these rivets are also automatically received in the joining device.

From the EP 3 117 925 A1 , which forms the basis for the preamble of claim 1, an ultrasonic punch riveting device with centering of the rivet is known. From the DE 103 32 124 A1 and the US 2004/217144 A1 conventional self-piercing riveting devices with springs are known which center the rivet.

Disclosure of the invention

According to the invention, a punch riveting device, a production system and a method for operating a punch riveting device with the features of the independent claims are proposed. Advantageous configurations are the subject of the subclaims and the description below.

The invention is based on a setting unit which is provided for a punch riveting device or which is used with a punch riveting device. A rivet can be held in the setting unit and it has a punch, by means of which the rivet can be subjected to force and introduced into at least one component in a riveting process.

One possibility of feeding and receiving in the case of self-piercing riveting devices, even with manual processing, is for example the use of a belt or the like in which several rivets are held in a predefined position and are arranged in a row. Such a strap can then be passed through the setting unit accordingly, so that, for example, a new rivet is placed in front of the punch after each riveting process. Belt tracking can be coupled with the movement of the setting unit, for example, or it can also be performed separately.

Another possibility, especially with larger series and with automatic processing, is to feed the rivets via a profile hose or something similar. Rivets can be guided in a predefined orientation in such a profile hose. The profile hose can then be connected to a suitable point in the setting unit, so that a rivet can be supplied in the desired position or inserted into the setting unit for a riveting process.

After the rivet has been inserted into the setting unit, it is usually necessary to hold the rivet in the setting unit until the rivet touches a component during the subsequent riveting process. In addition to the punch, the joining tool usually has a So-called hold-down device, which surrounds the punch and is used to guide the rivet during the riveting process. The hold-down device usually touches the component, while the punch is moved relative to the hold-down device in order to press the rivet into the component.

Various precautions can now be taken in the hold-down device to hold the rivet. For example, mechanical elements such as sprung half-shells, pressure pieces, rivet slides, flexible fibers, embedded balls or the like can be provided.

In the above-mentioned self-piercing riveting devices with ultrasound support (or with corresponding vibration coupling), not only the punch (or a corresponding sonotrode, of which a section can serve as a punch and in which the vibrations are transmitted) and the rivet are now vibrating offset, but also the mentioned, arranged in the hold-down mechanical elements, since these, in order to hold the rivet and also to ensure the guidance of the rivet, are in mechanical contact with it, and also the hold-down itself Hold-down or the mechanical elements arranged therein are very high and in particular significantly higher than with conventional punch riveting devices.

According to the invention, it is now proposed that a holding device be provided for the setting unit, which can be brought into a starting position and into a holding position in which the rivet can be fixed by means of the holding device by actuating the holding device. The holding device is designed in such a way that the rivet can be gripped by means of the holding device by moving it from the starting position into the holding position, and that the holding device can be released from the rivet by moving it from the holding position to the starting position is.

Such a setting unit thus makes it possible that the rivet is first gripped and thus fixed in a certain position and, in this position, is brought together with the setting unit to the desired location on the components to be connected. In the meantime, the holding device can be in the holding position in order to hold the rivet fixed or in position. According to the invention, a hold-down device is provided which surrounds the rivet and holds it in position. The holding device can then be in the starting position spent to loosen them from the rivet. According to the invention, the ultrasonic self-piercing riveting device has a vibration generator for generating vibrations that can be coupled to the punch, in which case there is no longer any contact between the holding device and the rivet or the punch (or the sonotrode) when the punch hits the rivet touched. If the punch does not yet vibrate at this point in time, it is also advantageous to fix the rivet between the punch and the component. Vibrations coupled into the rivet during the riveting process are therefore not transferred to the holding device and the latter is subject to significantly less wear. Wear on the outer surface of the punch, which was previously guided along the mechanical elements mentioned, is also avoided. It should be mentioned that such a holding device allows the rivet to be picked up and positioned quickly and easily, even with punch riveting devices without vibration coupling.

According to the invention, the holding device is mechanically coupled to the punch in such a way that the holding device can be brought into the holding position and / or into the starting position by moving the punch and / or when the punch reaches a predetermined position. A suitable linkage or the like can be provided for this purpose. Guides along suitable contours or the like are also conceivable. In particular, the holding device can have at least one spring element for this purpose, which can be actuated by the movement of the plunger and / or when the respective predetermined position of the plunger is reached, in order to bring the holding device into the holding position and / or into the starting position. Such a mechanical coupling enables a low-maintenance holding device.

According to the invention, the setting unit also has a hold-down device which at least partially surrounds the punch. This allows the components to be fixed on the one hand, and on the other however, the rivet can also be held in position after the holding device has been released from the rivet. The hold-down device can, for example, have suitable recesses for the passage of parts of the holding device in order to bring them up to the rivet.

The invention also relates to a production system with such a punch riveting device and a method for operating a punch riveting device with such a setting unit.

In the proposed method for operating a punch riveting device with a setting unit in which a rivet can be held, and with a punch, by means of which the rivet can be subjected to force and inserted into at least one component in a riveting process, the rivet is gripped by means of a holding device and then fixed. The setting unit is then moved in the direction of the at least one component, with the holding device being released from the rivet after the rivet touches one of the components. The rivet is then subjected to force by means of the punch and pressed into the at least one component.

According to the invention, a punch riveting device according to the invention is used in the proposed method, the holding device then being brought from the starting position into the holding position in order to grip the rivet, and the holding device being brought into the starting position in order to remove it from the rivet to solve, especially before the (vibrating) punch touches the rivet or before the punch begins to vibrate. In the latter case, it would also be possible to fix the rivet after releasing the holding device by means of the punch, which presses the rivet against the component.

With regard to the further refinements and advantages of the punch riveting device, the production system and the method, reference is made to the above statements on the setting unit according to the invention to avoid repetition.

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 claims.

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

Figure description

• Figure 1 shows schematically a punch riveting device with a profile hose for supplying rivets.
• Figure 2 shows various possibilities for holding a rivet in a setting unit of a punch riveting device.
• Figure 3 shows schematically an ultrasonic punch riveting device according to the invention in a preferred embodiment.
• Figure 4 shows schematically a production plant in a preferred embodiment.
• Figure 5 shows schematically a setting unit according to the invention in a preferred embodiment.
• Figure 6 shows schematically a setting unit which is not part of the claimed invention.

Detailed description of the drawing

In Figure 1 a conventional punch riveting device 10 'is shown schematically. 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 in a punch riveting device are usually arranged around the desired position relative to one another to be able to take. Via the frame 60, the punch riveting device 10 'can be attached, for example, to an arm for movement in space.

The punch riveting device 10 'has a punch 15, for example with a round cross section. The punch 15 is surrounded radially by a (sleeve-shaped) hold-down device 16 and is arranged to be movable relative to it in the longitudinal direction. The punch 15 and the hold-down 16 together form a joining tool 70 '. The punch 15 is coupled to a drive 50 which is used to apply a force F required to press the rivet 20 into the two components 11, 12. The drive 50 can be controlled, for example, by means of the computing unit 95.

The drive 50 can, for example, be 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.

The hold-down device 16 is also set up to press against the surface of the component 11 facing the punch 15 with a hold-down force. A separate drive can be provided for this purpose, for example. However, the hold-down device can also (as shown here) be coupled to the drive of the punch or to the punch itself, for example by means of a spring.

A counterholder in the form of a die 18 is arranged on the side of the two components 11, 12 opposite the punch 15 and the hold-down device 16. The punch 15 and the die 18 are arranged to be movable in the vertical direction, as is the hold-down device 16, and are movable relative to one another. 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 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 15, which rests flat against the upper side of the rivet 20.

Furthermore, a profile hose 17 is attached to the hold-down device 16, which is used to feed the rivets. Rivets can be individually inserted into the joining tool 70 via the profile hose, so that a new rivet is available for each new riveting process.

In Figure 2 various possibilities are shown of how the rivet 20 can be held in the setting unit 70 'or the hold-down device 16'. In Figure 2a the inside of the hold-down device 16 'is provided, for example, with fibers 40 which are directed downwards. The rivet 20 can be held in this way on the one hand, but on the other hand it can also be pressed down slightly by the punch and guided in the process.

In Figure 2b For example, the inside of the hold-down device 16 'is provided with downwardly directed supports 41 which are mounted by means of springs. The rivet 20 can be held in this way on the one hand, but on the other hand it can also be pressed down slightly by the punch.

In Figure 2c For example, a rivet slide 42 is provided on one side of the hold-down device 16 ', via which the rivet is pressed laterally into the hold-down device. The rivet 20 can be held in this way on the one hand, but on the other hand it can also be pressed down slightly by the punch.

In Figure 2d For example, the inside of the hold-down device 16 'is provided with embedded balls 43 which are made, for example, of elastomers or polymeric material. The rivet 20 can be held in this way on the one hand, but on the other hand it can also be pressed down slightly and guided by the punch.

The in the Figures 2a to 2d The mechanical elements shown in the hold-down device 16 'have in common that there is (at least almost) contact between the mechanical elements and the rivet during the entire joining process. In addition, the outer surface of the stamp is in contact with these elements. If vibrations were coupled into the punch here, the mechanical elements would also be set in vibration, which leads to increased wear. In addition, there is additional wear due to the contact between the punch and mechanical elements.

In Figure 3 an ultrasonic punch riveting device 10 according to the invention is shown schematically, which can also be used for a method according to the invention. The basic structure of the ultrasonic self-piercing riveting device 10 corresponds to that of FIG Figure 1 conventional punch riveting device 10 'shown, in this respect reference is also made to the description there. However, a vibration generator in the form of a vibration converter 30 with a signal generator 32 is provided, which together serve to generate ultrasound.

The ultrasonic punch riveting device 10 has a punch 15, which here also serves as a sonotrode, for example with a round cross section. Here, too, the punch 15 is surrounded radially by a (sleeve-shaped) hold-down device 16 and is arranged to be movable relative to it in the longitudinal direction. The hold-down device is preferably attached by means of a spring to a so-called zero amplitude passage of the ram, i.e. a position of the ram at which the oscillation amplitudes are zero or at least as low as possible. In particular, the punch 15 is coupled to a drive 50 which serves to apply a force F required to press the rivet 20 into the two components 11, 12. The drive 50 can be controlled, for example, by means of the computing unit 95.

The punch 15 is operatively connected to the vibration converter 30 via a so-called booster 31, so that the ultrasonic vibrations can be transmitted to the punch 15 and thus the rivet 20. 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 higher are generated . The signal generator 32 is connected to the computing unit 95 and can be controlled by it.

A frame 35 is attached to the drive 50, on which the vibration converter 30, the booster 31 and the punch or sonotrode 15 are arranged, the punch 15 and the holding-down device 16 attached to it forming a setting unit 70. Furthermore, the setting unit 70 has a holding device 80, which is only shown roughly schematically here. For a detailed illustration and explanation of the holding device, refer to the Figures 5 and 6 referenced.

In Figure 4 is simplified and shown schematically a production system 100 according to the invention in a preferred embodiment. 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 3 is shown in more detail, arranged.

Furthermore, a storage container 110, for example a magazine, is provided in which rivets can be kept. The ultrasonic punch riveting device 10 can then, for example, be moved via the arms to the storage container 110 in order to remove a rivet from there.

In Figure 5 a setting unit 70 according to the invention is shown schematically in an embodiment, on the basis of which a method according to the invention is to be explained. The setting unit 70 can, for example, in the case of the in Figure 3 Find punch riveting device shown use.

As already mentioned, the setting unit 70 has a holding device 80, which here in turn has holding elements 83 which are connected to the punch or the sonotrode 15 via springs 83. The holding elements 83 can now be pressed in the direction of the rivet 20 by means of springs 84. The holding elements 83 are guided here, for example, through suitable openings in the hold-down device 16. In the illustration shown above, the holding device 80 is in the holding position P _H.

The setting unit 70 can now be guided in the direction of the components 11, 12 until the rivet 20 and the hold-down device 16 rest on one of the components, as shown in the illustration below. The hold-down device 16 can be pressed against the component 11 by suitable springs when the punch 15 moves in the direction of the components.

In addition, when the punch 15 moves via the springs 82, a force is exerted on the holding elements 83, so that these are pushed apart and away from the rivet 20 against the spring force of the springs 84 due to the inclined surfaces on the holding elements 83. The holding device 80 is thus in an initial position P _A in which it does not touch either the rivet 20 or the hold-down device 16.

Then the riveting process, in which the rivet 20 is subjected to force via the punch 15 and is pressed into the components 11, 12, can be carried out. The setting unit can then be moved away from the components and, for example, to the in Figure 4 storage container 110 shown are guided to receive a new rivet. For this purpose, the holding device can initially continue to be left in the starting position and then, as soon as it is suitably placed for the new rivet, it can be brought into the holding position.

It goes without saying that the spring forces of the springs 82 and 84 should be suitably matched to one another in order to move the holding device 80 as desired when the punch 15 is in a desired position or movement. It should also be noted that the holding elements 83 are to be fastened in a suitable manner to the setting unit or possibly also to the punch riveting device.

In Figure 6 a setting unit 71 is shown schematically, which is not part of the claimed invention. The setting unit 71 can, for example, also be used in the in Figure 3 Find punch riveting device shown use. In comparison to the embodiment according to Figure 5 there is no mechanical coupling of the holding device provided here, but the holding device 85 has electrical actuators 87 which can move the holding elements 88. Instead of the electrical actuators, compressed air actuated actuators could also be used, for example.

These holding elements 88 can now be moved by suitable control of the actuators 87 such that the holding device 85 can be brought into a holding position P _H and an initial position P _A. As for the rest, the setting unit 71 can, as was already the case with the setting unit 70 in relation to FIG Figure 5 explained to be used for a riveting process. Continue to be noted that the actuators 87 and holding elements 88 are to be attached in a suitable manner to the setting unit or possibly also to the punch riveting device.

Claims (3)

1. Punch riveting device (10) having a setting unit (70, 71), in which setting unit (70, 71) a rivet (20) can be held, and having a punch (15) by means of which the rivet (20) can be subjected to force (F) and can be introduced into at least one component (11, 12) in a riveting operation,
   wherein the setting unit (70, 71) has a holding-down means (16) which at least partially surrounds the punch (15),
   wherein the punch riveting device (10) takes the form of an ultrasonic punch riveting device having a vibration generator (30, 32) for generating vibrations which can be coupled into the punch (15),
   characterized by a holding device (80, 85) which, by actuating the holding device (80, 85), can be brought into a starting position (P_A) and into a holding position (P_H) in which the rivet (20) can be fixed by means of the holding device (80, 85),
   wherein the holding device (80, 85) is designed in such a way that that, by being brought from the starting position (P_A) into the holding position (P_H), the rivet (20) can be gripped by means of the holding device (80, 85), and, by being brought from the holding position (P_H) into the starting position (P_A), the holding device (80, 85) can be released from the rivet (20),
   wherein the holding device (80, 85) is designed in such a way that, in the starting position (P_A), there is no longer any contact between the holding device and the rivet, between the holding device and the holding-down means (16) and between the holding device and the punch when the punch contacts the rivet, wherein the holding-down means (16) surrounds the rivet (20) and holds it in position, and
   wherein the holding device (85) has holding elements (83) which are connected to the punch via first springs (82), and wherein second springs (84) are provided by means of which the holding elements (82) can be pressed in the direction of the rivet, wherein the holding device is configured in such a way that, upon a movement of the punch, a force is exerted on the holding elements (83) by way of the first springs (82), with the result that, by virtue of oblique surfaces on the holding elements (83), the latter are pressed apart counter to the spring force of the second springs (84) and away from the rivet (20), with the result that the holding device (80) is situated in the starting position (P_A) .
2. Production unit (100) having a punch riveting device (10) according to Claim 1.
3. Method for operating a punch riveting device (10) according to Claim 1,
   wherein the rivet (20) is gripped by means of a holding device (80, 85) and then fixed,
   wherein the setting unit (70, 71) is then moved in the direction of the at least one component (11, 12),
   wherein, after the rivet (12) contacts one of the components (11), the holding device (80, 85) is released from the rivet (20), and
   wherein the rivet (20) is then subjected to force (F) by means of the punch (15) and is pressed into the at least one component (11, 12),
   wherein the holding device (80, 85) is brought into the holding position (P_H) in order to grip the rivet (20), and
   wherein the holding device (80, 85) is brought into the starting position (P_A) in order to release it from the rivet.

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