EP2754512B1 - Joining device and method for joining components without predrilled holes by means of a joining element which is subjected to pulsed forces - Google Patents

Description

The invention relates to a joining device for pre-hole joining of at least two components by means of joining element, which is driven (at a joint) in an axial joining direction with a jerky joining pulse in the components to be joined, wherein the joining device has a C-shaped frame with two opposing frame legs , between which the components to be joined are positioned during the joining operation, and a setting tool and a die, which are arranged opposite one another on the frame legs of the frame.

The invention further relates to a method for pre-hole-free joining of at least two components with at least one Fügelement which (without pre-punching) is driven in an axial joining direction with a jerky joining pulse in the components to be joined.

A joining device of the type mentioned above serves for the mechanical joining of components with the aid of at least one joining element or joining auxiliary part in the case of two-sided joint accessibility. The joining of the components takes place at a provided joint without pre-punching, to which the components are positioned overlapping between the frame legs of the C-shaped frame and then driven the joining element with the setting tool against the die in the components to be joined and thereby a positive and / or non-positive joint connection is generated. In this case, the joining forces occurring, sometimes in the two- to three-digit kN range, are absorbed by the C-shaped frame. The components to be joined can be joined at several joints one after the other with the same joining device. The movements can be accomplished with a manufacturing robot or the like, to which the joining device is connected.

Is one of the components to be joined formed from a high-strength material high joining forces are required, which must be applied by the setting tool against the die. Other boundary conditions can lead to high joining forces. In order to accommodate high joining forces, the C-shaped frame must be made rigid, causing this either heavy and bulky and / or bulky and unwieldy (due to disturbing stiffening contours or interference contours) is. Furthermore, the force-generating device of the setting tool must be designed for such a high joining force, which also requires a heavy construction. A remedy here are joining devices in which the joining element with a force pulse generated by the setting tool or setting tool (referred to as joining pulse hereinafter) penetrates at the joint at a high speed into the components to be joined, wherein the joint connection is brought about within a few milliseconds.

The prior art is based on the patents DE 10 2005 054 242 A1 and DE 10 2005 038 973 A1 the same applicant.

From the DE 197 29 368 A1 , on which the preamble of claim 1 is based, a joining device with a C-shaped frame is known, which has a striking mechanism with which a joint element can be hammered into the components to be joined by a plurality of successive impacts. Furthermore, the die is mounted resiliently or elastically with respect to the die-side frame leg. The joining force needed to make a joint connection is not applied in a single stroke (joining stroke).

The invention has for its object to provide a joining device of the type mentioned, which does not have at least one associated with the prior art disadvantage or at least only to a reduced extent.

This object is achieved by a joining device according to the invention with the features of claim 1. With a sibling claim, the solution of the problem also extends to an inventive method for pre-hole joining of at least two components by means of a joining device according to the invention. Further developments and embodiments are analogous to both subject invention both from the dependent claims and from the following explanations.

The joining device according to the invention for pre-hole-free joining of at least two components by means of joining element, which is driven in an axial joining direction with a jerky joining pulse in the components to be joined, comprises a C-shaped frame, the two opposing frame legs, between which positions the components to be joined be, and further comprises a setting tool and a die, which are arranged opposite to the frame legs. The die is decoupled relative to the die-side frame limb (ie in the context of constructive specifications), for which the die, for example, is flexibly mounted or held in the joining direction of the joining element on the die-side frame limb, so that a when the joining element is driven into the components from the die taken residual residual pulse transmitted only partially and / or only with a time offset on the matrix side frame leg or introduced into the frame legs.

The joining device according to the invention is characterized in that the die is connected to a (in the sense of at least one) arranged on the other side of the die-side frame leg mass body, said mass body is resiliently mounted in the joining direction of the joining element relative to the die-side frame legs, so that this can absorb the residual joining moment acting on the matrix during joining.

Preferably, the joining device according to the invention is provided for the connection to a multi-axis manufacturing robot and has a corresponding connection element or a flange portion or the like.

The joining device according to the invention can be operated with different joining element types, wherein the setting tool and the die are respectively designed accordingly. A joining element is in particular a rivet, in particular a solid rivet or hollow punch rivet, a resistance welding element, a nail-shaped or T-shaped joining element or the like.

In the components to be joined are, for example, to (metallic) sheet metal components or sheet metal-like components made of plastic and plastic composite material (eg. CFK), metallic and non-metallic profile parts, metal castings, plastic castings and the like, in any combination (mixed construction). In particular, these are body components for producing a bodywork composite component or a vehicle body. The invention enables a mass production suitable mixing construction technique with short cycle times. It is preferably provided that the components are additionally glued together. At a joint, two or more components can be joined with one joining element. The joining device according to the invention can also be used for the mechanical bonding of a joining element to a single component be, for example, for punching a punch nut, a punching bolt or the like. The joining device according to the invention can also be used for pure cutting or punching processes.

It is preferably provided that at least one of the components to be joined is formed from a high-strength material and in particular from a high-strength steel sheet material, such as, for example, a press-hardened steel sheet. A higher-strength material is primarily understood as meaning a material which has a tensile strength of at least 800 MPa and in particular of at least 1000 MPa. A press-hardened steel sheet material may have a tensile strength of up to 1500 MPa and more.

To join or connect the components they are positioned between the opposite frame legs or vice versa. Subsequently, the joining element to be set is acted upon by the setting tool with a jerky joining pulse and driven in a single uninterrupted, exclusively axial joining movement at the joint with high impact velocity in the components to be joined. Preferably, the impact velocity of the joining element in the range of 2 m / s [meters per second] to 99 m / s or 100 m / s and is, for example, about 30 m / s to about 50 m / s, so that the joining element when hitting the upper or the setting tool facing component having a high joining momentum. In this way, in particular components made of higher-strength materials without pre-punching can be joined together. Depending on the process variant, the components to be joined can be penetrated at the joint by the joining element or only partially penetrated. Also pre-punched components, in particular the upper component is pre-punched, can be joined with the joining device according to the invention.

The joining process which can be carried out with the joining device according to the invention is one-stage, ie only one single stroke (joining stroke) is carried out by the setting tool per joining operation. A nailing (for example, a punching nail or the like) with a plurality of successive bumps (by hammer mechanism or the like), as in DE 197 29 368 A1 is described, is not provided, but a sudden or shot-like operation, preferably after the piston push principle. The impulse-type joining pulse generated by the setting tool or setting device, which is transmitted to the joining element in particular with a joining punch or joining piston, is replaced by the Impact of the joining element and attenuated by the occurring deformation of the components and the joining element. The residual joining moment is taken up by the die (also referred to as counter-holder) and would be diverted into the C-shaped frame via the die-side frame leg without any further measures. This leads to dynamic loads on the frame, which would in particular result in bending or widening and / or swinging or ringing of the frame, in particular at the free ends of the frame legs, with considerable disadvantageous influences on the joining process.

In the case of the joining device according to the invention, the die is conditionally decoupled from the die-side frame limb, it is prevented that the residual joining moment picked up by the die during the joining process is introduced directly into the die-side frame limb.

The decoupling of the die relative to the die-side frame leg is achieved in particular by a flexible storage. Under a resilient mounting (or arrangement or mounting or attachment) of the die is understood that this is movable in the joining direction and against the joining direction relative to the die-side frame leg and longitudinally movably mounted in axial joining direction (that has a translational degree of freedom), wherein the relative mobility or longitudinal mobility is limited, which is accomplished, for example, by stops, spring travel or the like. Due to the relative mobility or longitudinal mobility is a constructive, d. H. limited, decoupling of the die relative to the die-side frame leg brought about. The decoupling prevents a direct transfer of the rest of the joint pulse received by the die into the die-side frame leg.

According to the invention, it is provided that the conditionally decoupled die is connected to at least one mass body arranged on the other side of the die-side frame leg. The mass body is arranged opposite the die on the other side of the die-side frame leg, with a force flow connection or force coupling between the die and the mass body. The die is arranged within the working space located between the frame legs and the mass body is outside of this working space arranged. The mass body is, as preferably also the die, resiliently mounted in the joining direction of the joining element with respect to the die-side frame leg, so that it can absorb the residual joining moment acting on the die during the joining, in such a way that the die acting on the die or received by the die Residual joining pulse is passed as a shock wave to the mass body, which can then move by impulse transmission relative to the die-side frame leg. Ie. the Restfügeimpuls received from the die is transmitted to the outside (out of the work space) on the matrix-side frame leg away on the mass body and there, depending on its mass, converted into a movement. In particular, in this case, the shockwave passes through the matrix-side frame limb substantially unhindered, without this being influenced by it (principle of the Newton pendulum).

The measures according to the invention lead to a considerable weakening and / or damping of the residual joining moment picked up by the die. Furthermore, above all, it is also possible to achieve a time delay in passing on the remainder joining pulse picked up by the matrix into the die-side frame limb. The attenuation and / or attenuation results in minimizing the effects on the widening and / or swinging of the frame. Ie. the die-side frame leg and the C-shaped frame do not need to accommodate the entire residual beat. A time delay leads, in particular, to the fact that the remainder of the joining pulse picked up by the die is passed on to the die-side frame leg only at the end or after the joining operation (which here means, in particular, the actual setting process when the joining element is introduced into the components) and, in particular, passed on in a weakened form , so that an expansion and / or swinging of the frame, if at all, takes place only at a late point in time which is uncritical with regard to the joining or setting process.

The invention does not start with the design of the frame but takes a different approach. Thus, on the frame side stiffening measures (such as, for example, a massive and heavy design or a complex and bulky truss structure) are largely dispensed with, so that the C-shaped frame of the joining device according to the invention even with a large radius (the usable length of the frame legs can, for example. 600 mm and more) may have a low weight and a compact design and contributes to a low system weight (including manufacturing robot, joining device and possibly additional components). In particular, it is possible to use a so-called lightweight C-frame which, for example, has a particularly lightweight truss structure or structure and / or frame parts made of carbon fiber reinforced plastic (CFRP). Furthermore, in principle, "soft" C-frame or C-bracket can be used.

It is preferably provided that the die and the mass body are arranged or fastened via a common die holder on the die-side frame leg, wherein the die holder is movable relative to the die-side frame leg. This also allows a one-piece design of female and female holders. Preferably, the die holder on a base body which connects the die and the at least one mass body.

In particular, it is provided that at least one spring device cooperating with the die and / or at least one spring device interacting with the mass body is arranged on the die holder. Such a spring device can serve, for example, the resilient mounting of the die or of the mass body on the die holder. Such a spring device can also serve to support the die or the mass body directly or indirectly resiliently against the die-side frame legs. A spring device converts kinetic energy into spring energy and vice versa. The spring device may be, for example, a coil spring, disk spring or the like. A spring device may comprise a plurality of spring elements of the same or different types. It is preferably provided that the spring device is an elastomeric spring device or at least comprises such an elastomer spring, as explained in more detail below.

Preferably, at least one damper or damping device is provided on the die holder in addition to at least one spring means, which can dampen occurring vibrations (the die, the mass body or the die holder throughout).

Instead of at least one separately formed spring device and at least one separately formed damping device may at the die holder at least one cooperating with the die spring damping device and / or at least one with be arranged the mass body cooperating spring damping device. Such a spring damping device (or spring-damper device) is designed as an integral structural unit or as a component. For example. the spring damping device is an elastomer spring device which has at least one elastomer spring. An elastomer spring combines resilient and damping properties, so that a possibly provided separate damping device is not required.

By tuning, the (at least one) spring means with the masses of the die, the die holder and / or the mass body, which provides quasi an additional mass, at least one spring-mass system and in particular a damped spring-mass system (spring damper Mass system), provided that (at least) a damping device is provided form. On the basis of the given physical laws, such a spring-mass system can have a positive influence on the temporal course of the reaction after the acceptance of the residual joining pulse by the matrix, in particular with regard to the joining process. Furthermore, the reaction forces transmitted to the die-side frame leg can be considerably reduced, whereby the expansion or rebound between the frame legs is reduced. Depending on the size, design, arrangement and combination of at least one mass body, at least one spring device, and at least one damping device different effects can be achieved in different proportions and an individual adaptation to the joining process can be achieved.

It is preferably provided that the (at least one) mass body, the (at least one) spring device, the (at least one) damping device and / or the (at least one) spring-damping device are designed as separate and preferably also interchangeable components, which in particular interchangeable or . are exchangeably attached to the die holder. Preferably, these components are designed to be adjustable in order to adjust the effects achieved and in particular to be able to set exactly. The die holder may include a mounting mechanism that is configured to permit a direct change of the mass body, the spring device, the damping device, and / or the spring damping device. By a direct exchange or exchange is meant that these components can be replaced without the need for the die holder must be removed from the C-shaped frame. By replacing these components, an individual adaptation to the joining process can be achieved.

At least one temporally resolving measuring sensor, which can be used for process monitoring, as explained in more detail below, can be arranged on the matrix, on the mass body and / or on the die holder. It is preferably a force measuring sensor (for example a piezo force measuring element) and / or an acceleration sensor (acceleration pickup).

The joining device according to the invention can be connected to a handling device, which is in particular a multi-axis manufacturing robot, in order to be able to move it in space with the handling device or the manufacturing robot. Since the joining device according to the invention can be designed to be light and handy, fast movements and high accelerations or delays are made possible. Furthermore, the handling device or the manufacturing robot can be equipped with relatively small-sized drive units (in terms of size and power or energy consumption). The required space or space requirement is relatively low.

The inventive method for pre-hole-free joining of at least two components provides that at least one joining element is driven with the aid of or using a joining device according to the invention with a jerky joining pulse in the components to be joined. For this purpose, the components to be joined between the frame legs, d. H. positioned in the working space, the C-shaped frame or vice versa. During the joining process, wherein a joining element is driven with a jerky joining pulse or with a high impact velocity into the components to be joined, the residual joining pulse acting on the die is transferred to the mass body or its additional mass. In the following reference is made to the preceding and following explanations.

If a plurality of joint elements are used for joining the components, the C-shaped frame and / or the components to be joined can be moved relative to one another after each joining operation, ie after a joining element has been set at a joint, which can be accomplished, for example, with the aid of the handling device , The invention Method is used in particular for producing a body composite component or a vehicle body.

Preference is given to automated process monitoring of a joining process carried out with the joining device according to the invention, which can be done in particular in real time. For this purpose, for example, the measuring signals generated by a measuring sensor (as explained above) can be evaluated automatically to determine a fault-free joint connection (or i.O. connection). The automatic evaluation can be done with a computer, wherein a recorded force-time curve or waveform in the whole or in sections (or other recorded or detected characteristic process variables) is compared with target specifications for a faultless joint connection. With the process monitoring, in particular the mechanically functional properties of the joint connection produced, in particular their load-bearing capacity, can be verified. This also allows process monitoring for checking (and, if necessary, documentation) consistent mechanical connection properties.

Fig. 1

zeigt eine erfindungsgemäße Fügevorrichtung in einer perspektivischen Ansicht.

Fig. 2

zeigt eine Matrizenhalterung an der Fügevorrichtung gemäß Fig. 1 in einer Seitenansicht.

Fig. 3

zeigt eine andere Ausführungsmöglichkeit einer Matrizenhalterung an der Fügevorrichtung gemäß Fig. 1 in einer Seitenansicht.

Fig. 4

zeigt eine andere Ausführungsmöglichkeit einer erfindungsgemäßen Fügevorrichtung mit Fachwerkrahmen in einer Seitenansicht.

Fig. 5

zeigt in mehreren Diagrammen mögliche Kraft-Zeit-Verläufe für eine Reaktionskraft an den Matrizenhalterungen gemäß Fig. 2 und 3.

Further features and advantages of the invention will become apparent from the following exemplary description with reference to the figures. The directions used here with reference to the figures are only exemplary and may differ from real world conditions.

Fig. 1

shows a joining device according to the invention in a perspective view.

Fig. 2

shows a die holder on the joining device according to Fig. 1 in a side view.

Fig. 3

shows another possible embodiment of a die holder on the joining device according to Fig. 1 in a side view.

Fig. 4

shows another embodiment of a joining device according to the invention with truss frame in a side view.

Fig. 5

shows in several diagrams possible force-time curves for a reaction force on the die holders according to Fig. 2 and 3 ,

Fig. 1 shows a joining device 100 according to the invention, which has a C-shaped frame 110 with two opposite frame legs 112 and 114. 120 denotes a flange section for connecting the joining device 100 to a production robot (not shown). Such a flange portion may also be located on one of the frame legs 112 and / or 114. At the upper frame leg 114, a setting tool or setting device 130 is arranged. At the opposite lower frame leg 112 a corresponding with the setting tool 130 die 140 is arranged. The joining axis is marked L.

The joining device 100 is used for the mechanical joining of two (or more) overlapping components 210 and 220 by means of joining element 300. For this purpose, the components to be joined 210 and 220 are arranged in the working space between the frame legs 112 and 114 and at the joint with the mouthpiece 131 of Setting tool 130 fixed against the die 140, which requires a two-sided Fügestellenzänglichkeitkeit. When using adhesives this is pressed. Optionally, a separate hold-down for fixing the components 210 and 220 may be provided at the joint. Subsequently, in the setting tool 130, the joining element 300 is accelerated in the joining direction D through the mouthpiece 131, for example with a joining punch or joining piston performing a single joining stroke, and penetrates into the components 210 and 220 to be joined at high speed and with a high joining momentum associated therewith a, wherein within a few milliseconds, possibly also in less than a millisecond, a positive joining connection is brought about. By moving the joining device 100, further joining connections between the components 210 and 220 can be produced in the same way at other joints. The setting tool 130 can be operated magnetically or electromagnetically, electrically (for example by means of electric fields) or pneumatically.

A residual joining pulse picked up by the die 140 during the joining operation and in particular during the setting process would be transferred directly into the machine without any further measures die-side frame legs 112 are derived, which would lead to a designated S bending or widening and / or swinging of the frame 110 between the frame legs 112 and 114. This would, inter alia, a misalignment (angular offset and lateral offset, based on the joint joining axis L) between the setting tool 130 and the die 140 result, which in turn would adversely affect the joint connection produced.

To avoid this, it is provided that the die 140 is resiliently mounted relative to the die-side frame leg 112 in the joining direction D of the joining element 300 and thus decoupled conditionally relative to the die-side frame leg 112, so that the residual joining moment picked up by the die 140 when the joining element is driven in is transferred only partially and / or only with a time offset on the die-side frame leg 112. It is further provided that the die 140 is connected to a mass body, which is arranged on the other, side facing away from the die 140 side of the die-side frame leg 112, which mass body with respect to the die-side frame leg 112 in the joining direction D of the joining element 300 also yielding is stored or suspended, so that it can absorb the force acting on the die 140 during joining Restfügeimpuls or shock.

Fig. 2 shows a non-inventive arrangement of the die 140 on the die-side frame legs 112. The die 140 is secured with a die holder 150 indirectly on the die-side frame legs 112. The die holder 150 has an axially extending rod-like base body 151 (axial extent corresponds to the joining axis L; Fig. 1 ), on which a die receptacle 152 for the die 140 is formed. Alternatively, the main body 151 and the die 140 may be integrally formed. The main body 151 extends through a bore formed in the die-side frame leg 112.

With an eccentric bush arrangement, the alignment of the die 140 can be adjusted to the joining axis L and readjusted. To this eccentric bushing arrangement includes an eccentric bushing 157 which rests with a radially projecting collar on the top or inside of the die-side frame leg 112, extending through the bore in the die-side frame leg 112 therethrough and at the bottom or Outside of the die-side frame leg 112 is secured with the fastening nut 153. The main body 151 can move in the axial direction L relative to the sleeve-like eccentric bushing 157.

A first and a second elastomer spring 154a and 154b are arranged between the die receptacle 152, which is formed with a radially projecting shoulder on the leg side, and the frame leg 112. The elastomer springs 154a and 154b each have an elastomer body disposed between metal disks. Between the elastomer springs 154a and 154b there is a force measuring sensor 155, with which a reaction force opposing the setting direction D can be detected during a joining operation. With 156, the connection cable of the force measuring sensor 155 is designated. The die holder 150 may include a punch neck removal, not shown.

The first and second elastomeric springs 154a and 154b are disposed on the side of the die 140. The die 140 is supported via the elastomer springs 154a and 154b decoupled on the die-side frame leg 112. Furthermore, the die receptacle 150 has a third elastomer spring 154c, which is arranged with respect to the frame leg 112 on the side facing away from the die 140 side. The third elastomeric spring 154c is axially spaced via the eccentric bush 157 to the nut 153. By turning the central clamping and locking nut 158, the preload of the elastomer springs 154a, 154b and 154c and thus their spring and damping properties can be changed and adjusted. Constructive details are not shown.

The die 140 is resiliently mounted relative to the die-side frame leg 112 along the joining axis L in the joining direction D of the joining element 300. Ie. The die holder 150 or its base 151 is movable relative to the die-side frame leg 112 along the joining axis L together with the die 140. Due to the axial relative mobility between the die holder 150 and the die-side frame legs 112, these components are not rigidly connected.

The residual joining pulse received by the die 140 during a joining operation or setting process (ie when the joining element 300 is set) causes the die 140 to move together with the main body 151 in the joining direction D (as shown below or towards the outside). In this case, the elastomer springs 154a and 154b are stretched and generate (upward or inward-acting) restoring forces. this leads to finally to one of the joining direction D opposite return movement of the main body 151 (upwards or inwards), which can lead to overshoot. In this case, the third elastomer spring 154c is tensioned and generates a restoring force (acting downwards or outwards). Thus, the residual joining pulse received by the die 140 may cause the die holder 150 (together with the die 140) to vibrate relative to the die side frame leg 112, this vibration being damped by the damping effects of the elastomer springs 154a, 154b and 154c. As a result, the residual joining pulse received by the die 140 when the joining element 300 is driven in is transferred only partially and / or only with a time offset to the die-side frame leg 112. As a result, the widening and / or swinging S of the frame 110 can be minimized and / or shifted to a time window which is not critical with respect to the joining operation or setting process.

Fig. 3 shows an inventive embodiment of a die holder 150. The same components and elements are denoted by the same reference numerals as in Fig. 2 designated. In this embodiment, a force measuring sensor 155 and a first elastomer spring 154a are arranged on the side of the die 140. On the side remote from the die 140, a second elastomeric spring 154b, a mass body 159 and a third elastomeric spring 154c are arranged. With 157 is designated an eccentric bush, as in connection with in Fig. 2 illustrated embodiment possibility explained. The elastomer springs 154, the force measuring sensor 155 and the mass body 159 are annular and are held in a form-fitting manner on the projecting rod-like base body 151. The attachment is made by the central nut 158. By loosening the nut 158, the mass body 159 and the mass body side elastomeric springs 154b and 154c can be replaced, without requiring the entire die holder 150 must be dismantled from the die side frame leg 112. The mass body 159 may be formed in one piece or in several parts (for example in the form of individual mass or weight disks). Furthermore, the in Fig. 2 and Fig. 3 shown features are combined within the scope of the invention to further embodiments of the invention.

The mass body 159 supported by the two adjacent elastomer springs 154b and 154c can be moved relative to the main body 151 in the axial direction L, with the main body 151 in turn being relatively movable with respect to the matrix-side frame leg 112. The middle Elastomeric spring 154b may be omitted if desired. The mass body 159 provides a sluggish additional mass, which counteracts the inertia so to speak of the rest of the matrix received 140, the elastomeric springs 154b / 154c and the mass body 159 are coordinated and form a spring-mass system. The die-side elastomeric spring 154a plays only a minor role with respect to the mass-side elastomeric springs 154b and 154c and can also be omitted if necessary. The additional mass or mass body 159 essential for the invention and the spring-mass system or spring-damper mass system formed in cooperation with the elastomer springs 154b and 154c are located outside the working space of the joining device spanned by the frame legs 112 and 114 100. The mass body 159 may, for example, have a mass in the range of several hundred grams to several kilograms. Incidentally, the explanations regarding in Fig. 2 shown execution option.

At the in Fig. 3 embodiment shown, the residual joining pulse picked up by the die 140 is likewise not introduced directly into the die-side frame limb 112, but is initially displaced as a shockwave through the die holder 151 via the die-side frame limb 112 to the additional mass of the mass body 159 and is displaced backward therefrom with a time delay (FIG. Newtonian rocker) and attenuated or attenuated introduced into the die-side frame leg 112, which takes place with respect to the joining operation or setting process at an uncritical late time. In other words, this means that the mass body 159 connected to the female mold 140 by the main body 151 is accelerated by the remainder of the joining pulse D received by the female mold 140 in the jointing direction D by the female mold 140 discharging the picked-up residual joining pulse to the mass body 159 (ie Residual momentum is transferred into the additional mass) and thereby is not accelerated itself (principle of Newton's pendulum). Thereby, the widening and / or swinging S of the frame 110 can be significantly reduced. This has an influence on the temporal force curve of a reaction force measured on the die holder 150 (see Fig. 5 ), whereby the joining process and in particular the setting process are positively influenced.

Both in the embodiment according to Fig. 2 as well as in the embodiment according to Fig. 3 Spiral springs, disc springs or the like instead of Elastomeric springs may be provided. A damping can be accomplished with separate damping devices or damping elements.

Fig. 5 shows several recorded with the force measuring sensors 155 force-time curves (force-time diagrams) for the same performed with the joining device 100 joining operations. The measured reaction force is plotted in kilonewtons [kN] (ordinate axis) over time in milliseconds [ms] (abscissa axis). The illustrated force-time curves can be detected or registered, for example, with the aid of the measuring sensor 155 arranged between the die 140 and the die-side frame limb 112 and thus positioned close to the die. The die-side elastomer springs 154 in this case cause a mechanical smoothing of the measurement signal. The measuring sensor 155 is preferably a piezoelectric force measuring element. A high measuring frequency of, for example, 200 kHz enables a precise temporal resolution of the generated measuring signal.

Fig. 5a shows the force curve F (t) of the measured reaction force to a die holder 150 without spring means, damping devices and additional masses. The fissured force curve F (t) has several similar partly high peaks. Fig. 5b shows the force curve for a die holder according to Fig. 3 which is equipped only with an additional mass and without spring and damping devices. Opposite the in Fig. 5a shown force curve, this force curve has fewer peaks, but higher peak values. Overall, however, shows a harmonization of the force curve, which is advantageous, inter alia, for the system load. Fig. 5c shows analogously to Fig. 5b the force curve with a higher additional mass on the die holder (without spring and damping devices). Fig. 5d shows analogously to Fig. 5b the force curve with additionally installed elastomer springs. Fig. 5e shows analogously to Fig. 5c the force curve with additionally installed elastomer springs. Fig. 5f shows the force curve in a die holder according to Fig. 2 which has no additional masses.

The in the Fig. 5d, 5f and 5e shown force curves F (t) have only two distinct peaks or maxima. The temporally first and higher peak (punching peak) represents the impact of the joining element 300 on the upper component 210. The second tip represents the striking of the joining element head 310 on the upper component 210 at the end of the setting process. The smoothed by the elastomeric springs 154 and optionally additional masses 159 force curve or waveform can be excellent for automated real-time process monitoring be used to establish a faultless joint connection.

The invention makes it possible to equip the joining device 100 with a relatively light frame 110. The C-shaped frame 110 must be designed so that it absorbs the static forces, which may for example be in the range up to 9 kN, when setting the mouthpiece 131 for fixing the components 210 and 220 against the die 140, largely free from deformation can. By virtue of the invention, the dynamic forces which occur during a joining operation or setting process can be handled without the C-shaped frame 110 having to be excessively stiffened for this reason and therefore heavy and bulky or unwieldy. Furthermore, the C-shaped frame can be at least partially made of lightweight materials, such as, for example, aluminum or fiber-reinforced plastic, in particular carbon fiber reinforced plastic (CFRP). Cast alloys, which sometimes have very good vibration damping properties, can be used. Thus, the C-shaped frame may be at least partially formed of an aluminum and / or magnesium casting alloy.

Fig. 4 shows a C-shaped frame 110 with a truss structure, which is particularly well suited for the invention. The truss frame 110 is very light and, since it only needs to absorb relatively low dynamic forces, also sufficiently rigid. In the truss frame 110, the frame legs 112 and 114 are each formed of two struts. The setting tool 130 is fastened to the upper frame limb 114 with a linear actuator or a feed unit 135. With the actuator 135, the setting tool 130 can be moved in the axial direction L to put the tubular mouthpiece 131 on the between the frame legs 112 and 114 and to be joined components and bring about a fixation of these components for the subsequent joining process.

An advantage of a joining device according to the invention is its low weight, which contributes to a low system weight. Furthermore, a good and above all nimble handling, especially on a manufacturing robot, allows. In addition, due to non-existent or only small interference contours, good accessibility to the joints, in particular on and in vehicle bodies, is made possible. Further advantages are a low noise (muffled sound) during the Joining, and in particular during the setting process (with respect to conventional Impulsfügevorrichtungen), independence from the materials of the components to be joined and achievable extremely short process times, resulting in short cycle times. These factors favor the preferred use in large-scale production.

LIST OF REFERENCE NUMBERS

100

joining device

110

frame

112

Frame legs (on the die side)

114

frame legs

120

flange

130

setting tool

131

mouthpiece

135

Actuator (infeed unit)

140

Die (counterholder)

150

die holder

151

body

152

die holder

153

mother

154

Spring device (elastomer spring)

155

Measuring sensor (force measuring sensor)

156

connection cable

157

eccentric

158

mother

159

mass body

210

upper component

220

lower component

300

joining element

D

joining direction

F (t)

force curve

L

joining axis

S

Expansion / Aufschwingung

Claims (10)

1. Joining apparatus (100) for joining at least two components (210, 220), without prepunching, by means of a joining element (300) which is driven into the components (210, 220) to be joined in an axial joining direction (L) by way of a percussion-type joining impulse, having a C-shaped frame (110) which has two opposing frame limbs (112, 114), between which the components (210, 220) to be joined are positioned, and having a setting tool (130) and a die (140), which are arranged opposite one another on the frame limbs (112, 114), wherein the die (140) is conditionally decoupled from the die-side frame limb (112),
   characterized in that
   the die (140) is connected to a mass body (159) arranged on the other side of the die-side frame limb (112), wherein this mass body (159) is mounted so as to yield in the joining direction (D) of the joining element (300) with respect to the die-side frame limb (112), so that it can absorb the residual joining impulse that acts on the die (140) during joining.
2. Joining apparatus (100) according to Claim 1,
   characterized in that
   the die (140) and the mass body (159) are fastened to the die-side frame limb (112) via a common die holder (150), wherein the die holder (150) is movable relative to the die-side frame limb (112).
3. Joining apparatus (100) according to Claim 2,
   characterized in that
   at least one spring device (154a) that interacts with the die (140) and/or at least one spring device (154b, 154c) that interacts with the mass body (159) is arranged on the die holder (150).
4. Joining apparatus (100) according to Claim 3,
   characterized in that,
   in addition to at least one spring device (154), at least one damping device, which can damp vibrations that occur, is also provided on the die holder (150).
5. Joining apparatus (100) according to Claim 2,
   characterized in that
   at least one spring/damping device (154a) that interacts with the die (140) and/or at least one spring/damping device (154b, 154c) that interacts with the mass body (159) is arranged on the die holder (150).
6. Joining apparatus (100) according to one of the preceding claims,
   characterized in that
   the mass body (159) is configured as a separate component.
7. Joining apparatus (100) according to Claim 6,
   characterized in that
   the die holder (150) has a fastening mechanism for the mass body (159), which is configured so as to allow direct changing of the mass body (159).
8. Joining apparatus (100) according to one of the preceding claims,
   characterized in that
   the C-shaped frame (110) is a lightweight C-frame.
9. Joining apparatus (100) according to one of the preceding claims,
   characterized in that
   at least one temporal resolution measuring sensor (155), which is usable for process monitoring, is arranged on the die (140), on the mass body (159) and/or on the die holder (150).
10. Method for joining at least two components (210, 220) without prepunching, in particular for producing a composite body component or a vehicle body, wherein at least one joining element (300) is driven into the components (210, 220) to be joined by way of a percussion-type joining impulse with the aid of a joining apparatus (100) according to one of the preceding claims.

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