Ultrasonic welding device and method of bonding by means of an ultrasonic wave

European).

ΕΡ 2,566.652 Β1

V14304PL00 / N

Description [0005] The description ΕΡ 1 930 148 Α1 discloses an ultrasonic welding device using a so-called torsional sonotrode. This is a sonotrode, essentially made with rotational symmetry, on which one working side is provided on one side of the sheet. In the vicinity of the other end face, inverters are coupled to the peripheral surface of the torsional sonotrode, by means of which they are transmitted to the sonotrode with a twisting vibration directed around the steering axle. As a result, the work surface, pressed against the connected construction elements, moves back and forth along an arc line corresponding to the circumference of the torsional sonotage. The disadvantage here is that the power transferred to the connected structural elements in the radially-lying section of the work surface, it is smaller than in the radially outside of the working area. As a result, the weld connection between the joining construction elements is not uniform.

The object of the invention is to eliminate the disadvantages of the prior art. In particular, a sonotrode is to be developed, by means of which the power delivered by the converter can be transferred to the working surface with improved efficiency. Improved power transmission efficiency is to be achieved especially when exerting high pressure. According to a further object of the invention, an ultrasonic welding device and a method for producing a weld connection by means of ultrasound, which enable efficient and even production of the welded connection between the connected construction elements, is to be developed.

This object is solved by means of the features of claims 1 and 15. According to the invention, an ultrasonic welding device comprising a torsional sonotrode with two facing faces and a circumferential surface surrounding the axis is proposed. steered, on which at least one working surface is provided at a radial distance from the steering axle. According to the invention, unlike the prior art, the work surface is no longer located on one of the end faces, but on the peripheral surface surrounding the steering axle. As a result, all surface elements of the working surface have substantially the same radial distance from the torsional axis. On the main section of the working surface, even power can be transferred to the components to be welded. The weld connection, made with the sonotrode according to the invention, is uniform.

[0008] Furthermore, the proposed torsional sonotrode allows substantially no power loss to be provided by the converter to the work surface. There are no uplifted movements on the connected surfaces between the torsional sonotrode, possibly provided by the buster and converter. The working surface makes a twisting movement around the steering axle, but not a longitudinal motion parallel to the steering axle. - The proposed torsional sonotrode is particularly suitable for producing a weld connection between metallic structural elements, for example between a twisted pair and a plug.

[0009] With the appropriate excitation of the proposed torsional sonotrode by means of ultrasound, there are little or no significant extensions in the axial direction, but twists in the transverse direction, as described by the shear modulus G. For the torsional vibration frequency, the following applies;

EP 2 566 652 Β1 η ίΰ ^V"2ί Jp, where η is an integer> 0, is the axial length of the torsional electrode, and p is the density of the torsional sonotrode.

[0010] The axial length 1 of the torsional sonotage is selected deliberately such that at a predetermined frequency v_n performs standing vibrations, or own vibration with wavelength λ. In this case, the working surface is provided centrally on the peripheral surface. - It is, however, also possible to select the axial length 1 of the torsional sonotage with respect to a predetermined frequency v_n in such a way that it is possible to generate by this vibration its own wavelength ηλ / 2, where n is an integer> 0. That is, the length 1 of the torsional sonotage can also be λ / 2, 3λ / 2, 2λ and so give .

[0011] According to the invention, a torsional sonotrode having on each circumferential surface at least one working surface is an annular surface, preferably radially protruding, which, with respect to the wavelength of the self-tapping sonotory, lies on the nodal line. Deliberately, the axial length 1 of the torsional sonotrode is chosen such that it corresponds to a predetermined ultrasonic frequency of exactly the wavelength λ of the self-vibration. In this case, the nodal lines are essentially at 1/4 and 3/4 of the length of the torsional myotage. The working surface can be located in this case between the nodes and is located essentially 1/2 of the length 1 of the torsional sonotrode.

[0012] Preferably, the torsional sonotrode is symmetrically shaped with respect to the symmetry plane extending perpendicularly through the torsional axis. According to a particularly advantageous configuration, the outline or the outline of the working surface is symmetrically shaped with respect to the plane of symmetry. This may in particular be such that the plane of symmetry through which at least one working surface and the working surface passes is symmetrical with respect to the plane of symmetry. This configuration of the torsional sonotrode is particularly simple. In this case, at least one working surface is placed in the center with respect to the axial length 1 of the torsional sonotage at its peripheral surface.

According to a further preferred embodiment, the torsional sonotrode has a central portion comprising at least one working surface that is releasably connected to the end portions extending on both sides thereof, each having one of the end faces. In this case, each of the end portions may have a ring surface. The connection between the end portions and the central part can be, for example, a screw connection. It can also take place that the two end parts are joined directly to one another, for example by means of a screw connection, and the central part is made as a ring which is shrunk onto the connected end portions. The projection of the central part, including the work surfaces, enables the work surface to be changed by replacing the central part.

ΕΡ 2 566 652 Β1 [0014] According to a further preferred configuration, the working surface is curved in the circumferential direction with a predetermined radius. The radius, on the one hand, has a beginning in the steering axle, i.e. in this case, the working surface is thus on the perimeter around the steering axle.

[0015] According to a further preferred embodiment, the working surface is a radially protruding peripheral annular working surface. Such an annular working surface allows particularly high durability of the torsional sonotrode. When the segment of the annular work surface is used, by turning the torsional sonotrode by a predetermined angle value, another unused portion of the annular work surface can be provided to produce further welded connections. Thanks to this, the number of welded joints can be reproduced with the proposed torsional sonotrode, compared to conventional sonotrodes.

[0016] According to a further preferred configuration, it is also possible that there are provided n work surfaces that are evenly distributed around the perimeter at an angle 3607η, wherein n is an integer> 1. In this case, the working surfaces are for example of the type anvils and protrude radially from the peripheral surface of the torsional sonotrode. Such work surfaces can, for example, be provided 2, 3, 4, 5, 6, 7, 8 or more. The use of a large number of work surfaces allows - as in the case of the use of an annular work surface - to allow quick replacement in the event of a working surface being worn. Such a torsional sonotrode has a particularly long shelf life. The conversion of one work surface to the other working surface can occur by simply rotating the torsional sonotrode. For this purpose, it is not necessary to replace or disassemble, [0017] According to a further preferred embodiment, the work surface has a structure, preferably slots. With respect to the axial direction, the grooves may run axially or diagonally. They can be placed in a crossed way. Furthermore, according to a preferred embodiment, it is possible to coat the work surface with a polycrystalline diamond (PKD). Such a PKD layer can for example be soldered to a work surface. As a result, the durability of the work surface can be increased and / or an undesired connection during welding, in particular aluminum, can be eliminated. [0017] According to a further preferred embodiment, the work surface has a structure, preferably slots. With respect to the axial direction, the grooves may run axially or diagonally. They can be placed in a crossed way. Furthermore, according to a preferred embodiment, it is possible to coat the work surface with a polycrystalline diamond (PKD). Such a PKD layer can for example be soldered to a work surface. As a result, the durability of the work surface can be increased and / or an undesired connection during welding, in particular aluminum, can be eliminated. [0017] According to a further preferred embodiment, the work surface has a structure, preferably slots. With respect to the axial direction, the grooves may run axially or diagonally. They can be placed in a crossed way. Furthermore, according to a preferred embodiment, it is possible to coat the work surface with a polycrystalline diamond (PKD). Such a PKD layer can for example be soldered to a work surface. As a result, the durability of the work surface can be increased and / or an undesired connection during welding, in particular aluminum, can be eliminated. it is possible to coat the work surface with a polycrystalline diamond (PKD). Such a PKD layer can for example be soldered to a work surface. As a result, the durability of the work surface can be increased and / or an undesired connection during welding, in particular aluminum, can be eliminated. it is possible to coat the work surface with a polycrystalline diamond (PKD). Such a PKD layer can for example be soldered to a work surface. As a result, the durability of the work surface can be increased and / or an undesired connection during welding, in particular aluminum, can be eliminated.

[0018] By means of the proposed ultrasonic welding device it is possible to transfer high power to the connected construction elements. As a result, relatively thick metal structural elements can be welded together with the perfect quality.

According to a preferred configuration, the further converter is connected radially to the next torsional vibration element, which is coupled to the other face of the torsional sonotory. In the case of the torsional vibrating element, for example, a cylindrical rod is used. Of course, it is also possible to couple radially several inverters with a torsional vibration element to generate torsional vibrations. Such types of torsional vibrations are known to those of the prior art. Reference is made to EP 1 930 148 A1, which discloses in the paragraphs [0039] and [0040] and in Figures 2 and 3 an element of torsional vibrations. In this case, the content of the disclosure of the document is included.

[0020] According to a further preferred configuration, the torsional vibration element, with indirectly switching the buster, is connected to the front side of the torsional sonotage. The booster's task is to change the amplitude provided by the inverter and pass it on to the torsional sonotage according to the invention. Depending on the construction of the booster, the amplitude can be reduced or increased. As a rule, busters are used

ΕΡ 2 5666 652 zwiększ1 increase the amplitude supplied by the inverter. The booster ratios can be, for example, 1: 1.5 to 1: 2.

[0021] According to a further embodiment, another converter for producing ultrasonic vibrations directed around the steering axle can be coupled to the other end of the torsional sonotory. The further converter can be connected radially to the next torsional vibration element, which is coupled to the other face of the torsional sonotrode. A suitable further torsional vibration device may have the same construction as the above-mentioned torsional vibration device. In particular, it may also be possible that the torsional vibration element, with the indirect inclusion of a further buster, is connected to the other face of the torsional sonotory. - With the aforementioned configuration it is possible to introduce particularly high powers for the torsional sonotrode. While,

[0022] According to the invention, a pressure device is provided for producing pressure on the working surface, operating substantially perpendicular to the torsional axis. In this case, it can be, for example, a pressure device, hydraulically driven, pneumatically or electrically. The pressure on the working surface can be produced by the fact that the torsional sonotrode is pressed against a fixed anvil or adjoining structural members against it by means of the work surfaces provided thereon. However, it is also possible that the torsional sonotrode is stationary and the anvil is pressed against the work surface.

[0023] In any case, it is expedient for the torsional sonotrode with the ring surfaces provided thereon to be supported by means of a support device. Because the annular surfaces adhere to the torsion line of the torsional sonotrode, no power is lost due to the proposed support.

[0024] The support device is connected to a pressure device. Thus, the torsional sonotrode can be moved by means of a pressure device to a stationary anvil.

[0025] Further, according to the invention, a method for producing a weld connection by ultrasound according to claim 15 is proposed.

[0026] According to an important feature of the method according to the invention, the working surface describes with respect to the ground a swing motion around the steering axle. In this case, the vibration plane, set perpendicular to the torsional axis, remains substantially unchanged, i.e. the working surface does not move or moves only slightly in a direction parallel to the torsional axis. By means of the proposed method, particularly high power can be transmitted to the connected construction elements. The vibration amplitude is the same in all places of the working surface. In this way, a particularly homogeneous welded connection can be produced.

[0027] In the case of a substrate, it may be a fixed anvil. However, it is also possible that the substrate is shaped like a further torsional sonotrode according to the invention. In this case, the torsional sonotrode and the further torsional sonotrode vibrate preferably in the opposite direction. In this way, the distance between the working surface of the torsional sonotrode and the further working surface of the subsequent torsional sonotrode is kept substantially constant. Thanks to this configuration, it can be carried even more significantly

EP 2 566 652 moc1 power for welding components to be welded. According to this embodiment, the construction elements to be welded can be maintained by means of a holding device fixed to the torsional sonotrode and a further torsional sonotrode, which prevents deflection of the construction elements to be welded together.

[0028] In the following, an embodiment of the invention is explained in more detail on the basis of the drawings. And so they show:

1 is a perspective view of the first torsional sonotrode, FIG. 2 is a top view according to FIG. 1, FIG. 3 shows a first side view according to FIG. 1 and FIG. 4 shows a second side view according to FIG. 1, FIG. on the side of the second torsional sonotrode, Fig. 5a, self-oscillation with a wavelength λ in the second tertiary sonotode, Fig. 6 a top view according to Fig. 5, Fig. 7 a cross-sectional view along section line AA in Fig. 5, Fig. 8 perspective view a third torsional sonotrode, FIG. 9 a side view according to FIG. 8, FIG. 10 a top view according to FIG. 8, FIG. 11 a sectional view along the section line AA in FIG. 9 and FIG. 12 is a schematic view of the welding apparatus ultrasound.

The first torsional sonotrode shown in FIGS. 1 to 4 has two mutually opposite round faces S1, S2, through which the midpoint extends in the first axis G1 and the second threaded hole G2, the circumferential surface U connecting the face S1. and S2, is cylindrically shaped here. The circumferential surface U is at least on certain sections an imaginary surface which in its geometry of the cross section corresponds substantially to the geometry of the end faces. The first torsional sonotrode has two cylindrically shaped end sections Ε1, E2. The first end section E1 is bounded by the first face side S1 and the second end section E2 by the second face side S2. Between the end sections E1, E2 has a central part M with two protruding from the peripheral surface U, mutually opposite protrusions V1, V2 in the kind of anvil. The first projection V1 has a first work surface A1 and the second projection V2 has a second work surface A2. The radial distance of the working surfaces A1, A2 from the steering axle, designated by the reference numeral T, is preferably larger than the radius of the peripheral surface U. It is, for example, 50 to 100 mm, preferably 60 to 90 mm. The radius of the peripheral surface can be 30 to 70 mm, preferably 40 to 60 mm. is preferably larger than the radius of the peripheral surface U. It is, for example, 50 to 100 mm, preferably 60 to 90 mm. The radius of the peripheral surface can be 30 to 70 mm, preferably 40 to 60 mm. is preferably larger than the radius of the peripheral surface U. It is, for example, 50 to 100 mm, preferably 60 to 90 mm. The radius of the peripheral surface can be 30 to 70 mm, preferably 40 to 60 mm.

[0030] On both sides of the central portion M, annular surfaces R1, R2, projecting radially on the center parts Ε1, E2 from the circumferential surface U are provided.

The first torsional sonotrode is symmetrically shaped with respect to the SY symmetry plane shown in Fig. 4. The SY symmetry plane is perpendicular to the torsional axis, designated with the T identifier. The end parts E1, E2 are here essentially rotatable-symmetrically shaped regarding the T steering axle

ΕΡ 2 566 652 Β 1 [0032] The second torsional sonotrode shown in FIGS. 5 to 7 has between the end portions E1, E2 a second central portion M2 that has four peripheral splines V1, V2, V3, V4 of the kind of anvil. The protrusions V1, V2, V3, V4 are each positioned in relation to each other by an angle of 90 °. In relation to the SY symmetry plane, they are symmetrically shaped. The working surfaces A1, A2, A3, A4, provided on the circumferential surfaces of each of the protrusions V1, V2, V3, V4, are shaped as curved in the circumferential direction. Their radius of curvature extends from the torsional axis T and in Fig. 7 is marked with the reference numeral R. Furthermore, as is particularly evident in Fig. 7, each of the working surfaces A1, A2, A3, A4 has a structure that can be formed for example by axial grooves, [0033] As is particularly evident in connection with the view of Fig. 5, the axial length I of the torsional sonotrode is such that at a predetermined uitradio frequency, the vertical vibrations λ shown in Fig. 5a are formed. Fig. 5a shows the amplitude +/- p of the two opposing vibration states on the torsional length I of the torsional sonotrode. The zero transitions of the standing vibration form the nodes of the nodes on which the ring surfaces R1, R2 are located. The torsional nervous torsion vibrates in such a way that the end parts E1, E2 move in each case counter to the central part M2. 5a shows the amplitude +/- p of the two opposing vibration states along the length of the torsional sonotrode. The zero transitions of the standing vibration form the nodes of the nodes on which the ring surfaces R1, R2 are located. The torsional nervous torsion vibrates in such a way that the end parts E1, E2 move in each case counter to the central part M2. 5a shows the amplitude +/- p of the two opposing vibration states along the length of the torsional sonotrode. The zero transitions of the standing vibration form the nodes of the nodes on which the ring surfaces R1, R2 are located. The torsional nervous torsion vibrates in such a way that the end parts E1, E2 move in each case counter to the central part M2.

[0034] In contrast to the embodiment shown in Figs. 5 to 7, it can also be provided that instead of the projections V1, V2, V3, V4 only one (not shown here) is provided, the annular projection on which it is shaped (here, not shown). shown) peripheral working surface. In addition, it is also possible that six or eight projections can be provided instead of the four projections V1, V2, V3, V4.

[0035] Figures 8 to 11 show a third torsional sonotrode. In the case of the third torsional sonotrode, the end portions E1, E2 on the section a1, a2, lying on the outside, with respect to the ring surfaces R1, R2, have a smaller diameter than the inner section a3, a4, located near the third central portion M3. Because of the different diameters of the end portions E1, E2 relative to the annular surfaces R1, R2, they have the effect of a booster. In addition, on the outer sections a1, a2, mutually opposite and parallel to each other faces f1, f2 and f3 and (here not shown) are provided f4. Surfaces f1 to f4 are used to fasten the tool.

[0036] The torsional sonotrodes shown in the examples are preferably made of one piece of metal. Although not shown in the above figures, it may also be that the central part M1, M2 is releasably connected to the end portions E1, E2, for example by means of a screw connection. The face ends S1, S2 can furthermore be provided with radially extending structures, for example grooves, ribs, recesses, plug bits the like, which allow a backlash-free connection with the buster or torsion bar.

[0037] Fig. 12 shows schematically in perspective view a structure of an ultrasonic welding device using a torsional sonotrode according to the invention, which in fig. 12 is generally designated as SO. The torsional SO-throttle on its first face side S1 is permanently connected by means of a screw connection to the first blister B1. In turn, the first borer B1 is connected with the first torsion bar T1 to which the first converter K1 and the second converter K2 are connected in a radially opposite arrangement. The AB marker is marked with an anvil which is stationary in relation to the torsional SO monortic. The SV support device indicated here schematically surrounds, for example in a clamping manner,

ΕΡ 2 566 652 Β1 annular surfaces R1, R2. The SV support device is connected to a pressure device D with which the device for ultrasonic vibrations, formed from the inverter K1, K2, torsion bar T1, bustor B1 and torsional sonotrode SO, is displaced vertically, with respect to the AB anvil and by means of which it can be pressure exerted on the second working surface A2, or (here not shown) connected construction elements, embedded between the second working surface A2 and the anvil AB.

[0038] The operation of the ultrasonic welding device is as follows:

With the help of inverters Κ1, K2, which are operated in the opposing phase, a torsional vibration, directed around the torsion axis T, is generated in the first torsion bar T1, the torsional vibrations are transferred through the first boom B1 to the torsional sonotrode SO. As a result, the protrusions V1, V2, or the work surfaces Α1, A2 provided therein, vibrate on a segment of the circular path about the torsional axis T. In this respect, the position of the projections V1, V2 in the axial direction remains substantially unchanged. In order to produce a welded joint (not shown here), two joined structural members are laid on the AB anvil. Then, by means of the pressure device D, the second working surface A2 of the torsional SOFTTOS is pressed against the construction elements lying one above the other. By running the K1 inverters, K2 produces a torsional vibration by means of which the construction elements are moved relative to each other. Thanks to the generated friction, a welded joint is created.

Although not shown in Fig. 12, of course also the second face S2 of the sonic torsion SO may be connected via (not shown here) the second buster B2 and (not shown here) the second torsion bar T2, with (not shown here) shown here) third and fourth converter K3, K4.

[0040] The device for ultrasonic oscillations, formed from converters, busters and torsional sonotrode, can also be placed still. In this case, the anvil AB may be vertically displaceable and provided with a pressure device. Furthermore, it is also possible to operate two devices for ultrasonic oscillations in an opposite configuration for producing a welded connection. Thus, in this case, a further torsional sonotrode is provided instead of the AB anvil. At the same time, the opposite torsional sonotrodes vibrate in opposite directions.

List of markers [0041]

<td>a1, a2</td><td>outside section</td>

<td>a3, a4</td><td>internal section</td>

<td>A1, A2, A3, A4</td><td>working surface</td>

<td>AB</td><td>anvil</td>

<td>B1</td><td>first buster</td>

<td>D</td><td>pressure device</td>

<td>E1</td><td>the first final part</td>

EP 2 566 652 Β1

<td>E2</td><td>the second final part</td>

<td>G1, G2</td><td>thread</td>

<td>f1, f2, f3, f4</td><td>surfaces</td>

<td>K1</td><td>first converter</td>

<td>K2 AND</td><td>second inverter axial length of the torsional sonotrode</td>

<td>M1</td><td>first central part</td>

<td>M2</td><td>second middle part</td>

<td>M3</td><td>third central part</td>

<td>R</td><td>radius of curvature</td>

<td>R1</td><td>first annular surface</td>

<td>R2</td><td>second annular surface</td>

<td>S1</td><td>first face</td>

<td>S2</td><td>second front side</td>

<td>SO</td><td>torsional sonotrode</td>

<td>SV</td><td>supporting device</td>

<td>SY</td><td>plane of symmetry</td>

<td>T</td><td>steering axle</td>

<td>T1</td><td>first torsion bar</td>

<td>at</td><td>peripheral surface</td>

V1, V2, V3, V4 performance