METHOD AND ASSEMBLY FOR ELECTROCONDUCTIVELY CONNECTING CONDUCTORS TO A RETAINING DEVICE

Description

[0001] The invention relates to a method for electrically connecting first electrical conductors and preferably second electrical conductors twisted with them in a compression chamber, the cross-section of which can be varied, in particular in height and width, and which is bounded at least by a side slider, a sonotrode and a counter electrode, by means of ultrasonic welding, wherein first bare ends of the first electrical conductors are introduced into the compression chamber and welded to form a first connection by means of ultrasonic action, and then, after removing the first connection from the compression chamber, bare ends of the second electrical conductors are introduced into it and welded to form a second connection by means of ultrasonic action.

[0002] Furthermore, the invention relates to an arrangement for joining first conductors and second conductors, which are in particular twisted together, by means of ultrasound, comprising a compression chamber bounded by at least one side slider, a sonotrode and a counter electrode, which is preferably surrounded by a housing, in particular sound-insulating, during welding.

[0003] Ultrasonic welding can be used to create a metallurgical bond between electrical conductors. The energy required for welding is introduced into the workpiece in the form of mechanical vibrations. For this purpose, a sonotrode is set into ultrasonic vibration along its longitudinal axis. Simultaneously, it moves relative to a counter electrode—also called an anvil—associated with the sonotrode to generate the necessary static welding force. The materials to be joined are positioned between the counter electrode and the sonotrode. In ultrasonic metal welding, the mechanical vibrations are applied parallel to the plane defined by the anvil. This results in a complex relationship between the static force acting between the sonotrode and the counter electrode, the oscillating shear forces, and the temperature rise in the joining zone.Typical frequencies for ultrasonic metal welding range between 20 kHz and 40 kHz, with the working frequency usually being in the range of 20 kHz.

[0004] Twisted pairs are used particularly in communications technology, but also, for example, in wiring harnesses in motor vehicles, to reduce mutual interference between individual insulating electrical conductors or cables. Connections between sections of individual conductors or cables can be made using ultrasonic metal welding, with the resulting connections also being referred to as through-connections.

[0005] To minimize electrical interference with the conductors containing through-joints, twisting should be present as much as possible in the area of ​​the through-joints. However, since the through-joints must be welded sequentially to prevent welding from being obstructed by an already welded through-joint, it must be kept away from the welding chamber. Because the welding chamber, or the components that define it, typically requires a soundproof enclosure, the twisting is carried out to such an extent that the already welded through-joint lies outside the soundproof enclosure. This, however, necessitates a considerable amount of twisting of the conductors.

[0006] From DE 10 2010 060 767 A1 (basis for the preamble of claims 1 and 4) a method and a device for welding conductors consisting of metallic strands or wires to a terminal or through node are known by introducing a first section of each conductor into a compression chamber of an ultrasonic welding device with a sonotrode and a counter electrode.

[0007] The present invention is based on the objective of further developing a method and an arrangement of the type mentioned at the outset in such a way that twisting is largely made possible even in the area of ​​a connection between the first conductors and a connection between the second conductors.

[0008] To solve the problem, the essentially proposed procedure is that, before welding the second connection, the first connection is fed into a holding device located in the immediate vicinity of the compression chamber.

[0009] In other words, the invention proposes that the welded first connection, i.e., the first through-joint, be received by a retaining device located in the immediate vicinity of the compression chamber. This ensures that minimal untwisting or unwinding is necessary to perform the welding of the sections of the further conductor or cable without causing any obstruction.

[0010] Naturally, the teaching according to the invention also applies to the welding of more than two twisted conductors running to each side of the compression space.

[0011] The containment device is located inside the soundproof housing, if one is present.

[0012] In particular, it is provided that the retaining device is formed in or on the side slide, the counter electrode or in or on the inside of the housing.

[0013] It is possible that the retaining device originates from sections of the housing interior or from an element closing the bottom of the housing, such as a base plate, from which components of the ultrasonic welding device originate directly or indirectly.

[0014] According to the invention, the untwisting length on both sides of the compression chamber can be reduced to approximately 30 mm to 40 mm. This offers the advantage of reducing mutual interference between the electrical conductors or cables; the shorter the untwisting length, the better the electromagnetic compatibility of the cable set with regard to the susceptibility of the entire cable harness to interference.

[0015] An arrangement of the type mentioned above is essentially characterized by a retaining device for receiving a first connection produced by welding bare ends of the first conductor during the welding of bare ends of the second conductor to form a second connection, wherein the retaining device is formed on the side slide or the counter electrode or, if the housing is present, in its welding joint retaining device on the side slide or the counter electrode, or, if the housing is present, originates from its interior or from an element closing the bottom of the housing, wherein the welding joint retaining device is formed as at least one element from the group consisting of recess, projection, bracket, hook, clamping device, gripping element, spring, and hold-down device.

[0016] The weld joint retention device is referred to below as the retention device.

[0017] The invention may also provide that a recess is formed as a retaining device on the upper side of the slide, located furthest from the bottom surface of the compression chamber. In particular, the recess, in a section running perpendicular to the end face of the side slide that bounds the compression chamber, has a geometry in the form of a triangle, in particular an isosceles triangle, a rectangle, a segment of a circle, in particular a semicircle, or one or more combinations thereof. The recess may also be designed as an undercut.

[0018] Alternatively or additionally, a rectangular or L-shaped projection can protrude above the top of the side slide as a retaining device, which, in particular on the compression chamber side, merges flush into the end face of the side slide that defines the compression chamber.

[0019] However, it is also possible to form a recess in the end face of the counter electrode facing the side slider, or to have a projection extending from the end face as a retaining device. In particular, it is intended that the projection merges flush with the surface of the counter electrode that defines the compression chamber, forming a section of the latter.

[0020] The retaining device can also extend from the housing or a section thereof. For example, the housing can comprise a stationary first section and a second section that is adjustable relative to it and preferably rests against it during welding, with at least one projection, particularly hook-shaped, extending from the first or second section to form the retaining device. In particular, it is provided that two spaced-apart retaining devices, such as projections, extend from the first or second section of the housing and reach onto opposite sides of the compression chamber.

[0021] Of course, a containment device can also originate from the base, which accommodates the components of the ultrasonic welding device and closes the soundproof housing on the bottom side.

[0022] Further details, advantages and features of the invention will become apparent not only from the claims and the features to be derived therefrom - individually and / or in combination - but also from the following description of preferred embodiments to be derived from the drawing.

[0023] They show: Fig. 1 a schematic representation of an ultrasonic metal welding arrangement, Fig. 2 a schematic representation of a compression chamber of an ultrasonic metal welding device, Figs. 3a-3f schematic representations of embodiments of side slides, Figs. 4a, 4b further embodiments of side slides, Fig. 5 an ultrasonic welding device with soundproof housing, Fig. 6 an ultrasonic welding device according to Fig. 5 with a differently designed soundproof housing, Fig. 7 the arrangement according to Fig. 6 , in which the first conductor of twisted conductors are welded together, Fig. 8 the arrangement according to Fig. 6 and 7with closed soundproof housing and Fig. 9 - 14 further embodiments of restraint devices.

[0024] The invention is explained using the figures, in which basically identical elements are provided with the same reference numerals, according to which individual conductors or cables that are twisted together can be welded without having to untwist or twist in the area of ​​the connections, so that mutual influence of the electrical conductors or cables is reduced.

[0025] This is of particular interest in the field of communications technology, but also in the automotive sector. The avoided mutual interference has a particularly positive effect on a vehicle's wiring harness, as it reduces the harness's susceptibility to interference.

[0026] In Fig. 1 An ultrasonic welding arrangement 110 is shown in principle to illustrate its essential elements. The arrangement 110 comprises an ultrasonic metal welding device 111, which is intended for welding conductors or cables.

[0027] The ultrasonic welding arrangement 110 comprises as essential elements a converter 112 and a sonotrode 114, between which a booster for amplitude amplification is arranged. The converter 112, the booster 116, and the sonotrode 114 form a so-called ultrasonic transducer 117, which is mounted in the booster. The sonotrode 114, i.e., its Fig. 1 The head, which is not visible and has a welding surface, is associated with a counter electrode 115, also called an anvil, which can be lowered to the oscillator 117 in order to introduce forces into the joining zones during welding, in this case to form through nodes of conductors or cables.

[0028] The anvil 115 is recorded from a so-called spotting plate 119 (see Fig. 2 ), which is adjustable perpendicular to the welding surface 1114 of the sonotrode 114. Opposite it is a side slide 113 which, together with the anvil 115, the sonotrode 114 or its welding surface 1114 and the spotting plate 119, defines a compression chamber 121 that is adjustable in height and width.

[0029] The converter 112 is connected via a line 118 to a generator 120, which in turn is connected to a computer via a line 122. The converter 112, i.e., the piezoelectric crystal disks arranged within it, is supplied with high-frequency voltage via the generator 120 to expand or contract the disks accordingly, thereby generating ultrasonic vibrations with an amplitude that is amplified by the booster 116 and transmitted to the sonotrode 114.

[0030] The vibration frequency is typically 20 kHz. The amplitude is usually between 0.010 mm and 0.045 mm per half-wave. The forces exerted on the cables during ultrasonic welding, from the anvil 115, can range from 150 N to 3000 N. The welding surface lies within the antinode of the ultrasonic vibrations.

[0031] Is based on the Fig. 1 Since a longitudinal oscillator has been explained, the teaching according to the invention is not departed from even if a torsional oscillator is used.

[0032] The ultrasonic welding device 111 is also typically surrounded by a soundproof housing 126, which is closed during welding. An example of such a housing is shown below. Fig. 5 to be removed. The soundproof housing 126 consists of a stationary section 128 and a section 130 that can be moved to it and is in contact with it during welding, and which in turn is surrounded by a housing part 132.

[0033] The housing 126 is closed at the bottom by a base plate 134, from which the components or tools extend or are stored, which are required, among other things, for the formation of the compression chamber 121. Such a chamber is, in principle, the Fig. 2 to be seen. One can recognize the sonotrode 114 with welding surface 1114, the side slide 113, the anvil 115 and the spotting plate 119, which surround the compression chamber 121.

[0034] The conductors to be welded are placed in the open compression chamber 121, and the side slide 113 is then moved towards the spotting plate 119 until the desired welding width is reached. The anvil 115 is then moved towards the side slide 113 while simultaneously lowering it by adjusting the spotting plate 119. After contacting the conductors, the sonotrode 114 is energized and welds them. Reference is made to well-known techniques in this respect.

[0035] According to the invention, first conductors 140, 142 are welded to each other and second conductors 144, 146 are welded to each other successively. The first conductors 140, 142 are twisted together with the second conductors 144, 146, as shown in the Fig. 5 , 7 and 8 can be seen.

[0036] The welding of the first conductors 140, 142 is carried out first. For this purpose, bare ends of the otherwise insulated conductors or cables 140, 142 are placed in the compression chamber 121, in order to then move the side slide 113 to the welding width in the manner described above, in order to then carry out the welding by adjusting the anvil 115 and the spotting plate 119 with the sonotrode 114 excited.

[0037] The free bare ends of the second conductor 144, 146 are positioned when the bare ends of the first conductor 140, 142 are inserted so that they cannot penetrate the compression chamber 121.

[0038] After welding the first conductors 140, 142, i.e., after creating a first connection 148, which can be referred to as a through-joint, the second conductors 144, 146 are inserted into the compression chamber 121. It must be ensured that the through-joint 148 cannot enter the compression chamber 121.

[0039] This can be achieved either by untwisting the first and second conductors over a longer distance or, according to the invention, by placing or hooking the through-node 148 onto a retaining device that is integrated into the ultrasonic welding device 111, in particular within the interior of the housing 126.

[0040] Thus, only a small amount of untwisting is required in the immediate vicinity of the through-node 148. Consequently, the effect of the twisting is essentially maintained, namely preventing the mutual influence of the first conductors 140, 142 to the second conductors 144, 146 and vice versa, an advantage that is reflected not only in communication technology, but also, in particular, in the field of automotive engineering.

[0041] To fix the through-node 148 so that the welding of the bare ends of the second conductor 144, 146 cannot be disturbed, various possibilities are given, as explained with reference to the figures.

[0042] A preferred embodiment is characterized in that the side slider 113 acts as a retaining device by means of recesses and / or projections or other aids. This can be seen from the Fig. 3 und 4 explained.

[0043] Thus, according to the exemplary embodiment of the Fig. 3a und 3b The side slider 113 has on its upper side 1113 a recess 150, 152 forming an oblique triangle in section, the short leg of which according to Fig. 3a located far from the front surface 154 of the side slide 113 or facing it ( Fig. 3b ) proceeds.

[0044] Notwithstanding the above, the recess or indentation 150, 152 ensures that the through-node 148 is fixed in place during the welding process. The recess or indentation 150, 152 extends across the entire width of the side slide 113.

[0045] According to the exemplary embodiment of the Fig. 3c A rectangular recess 156, running parallel to the front surface 154, is provided as a retaining device.

[0046] In Fig. 3d A slot 158 ​​extends from the upper surface 1113 and parallel to the front surface 154, which transitions into a circular extension 160 in cross-section, serving as a retaining device.

[0047] According to the exemplary embodiment of the Fig. 3e A channel-shaped recess 162 extends from the upper surface 1113 of the side slide 113, covering the entire width of the slide 113 and, in the exemplary embodiment, having the geometry of a semicircle. Another possibility for forming a retaining device in the side slide 113 is provided by an undercut 164 ( Fig. 3f ).

[0048] However, the function of a restraint device is also achieved by projections 166 and 168 extending from the upper surface 1113 ( Fig. 4a, b The projection 166, which does not necessarily have to extend across the entire width of the slide 113, has a rectangular geometry in cross-section and according to the Fig. 4b the of an L, so that a free space 170 is created facing away from the front surface 154, into which the through node 148 can be inserted or hooked.

[0049] However, a restraint device can also be formed in the anvil. This is demonstrated by the Fig. 2 This illustrates that a projection 174 can extend from the end face 172 of the anvil 115 on the slide side, creating a step between the end face 172 and the projection 174, onto which the through-node 148 can be placed. To avoid interfering with the welding process, the projection 174 merges flush with the underside 176 of the anvil 115 on the sonotrode side, which sectionally delimits the compression chamber 121.

[0050] In other words, the projection 174 is a section of the anvil 115 or the pressure surface itself. Instead of a projection, a recess 176 can be provided in the end face 172, into which the first connection or through-node 148 is inserted during the welding of the bare ends of the second conductor 144, 146.

[0051] However, according to the Fig. 5 The possibility also exists that a retaining device extends from the adjustable housing section 130. In the exemplary embodiment, webs or legs 178, 180 extend from the housing section 130, having hook-shaped upper surfaces 182, 184 into which the first connection or through-node 148 is inserted during the welding of the second conductor 144, 146. The legs 180 run laterally to the side slide 113 and thus to the compression chamber 121.

[0052] According to the exemplary embodiment of the Fig. 6 bis 8 Hook-shaped projections 186, 188 extend from the stationary housing section 128 and serve as a retaining device. The projections 186, 188 have a clear distance between them that ensures that the adjustment of the side slide 113 cannot be obstructed.

[0053] In Fig. 6 The opened case is shown. Fig. 7 The welding of the bare ends of the first conductors 140, 142 has already been completed. The first connection made, i.e., the first through-joint 148, is placed onto the hook-shaped sections 186, 188 in order to then weld the bare ends of the second conductors 144, 146. During the welding process itself, the housing 126 is closed, as can be seen from the Fig. 8 This results in the following: An end face of the adjustable section 130 rests against a geometrically adapted surface of the housing section 128.

[0054] To ensure that the first and second conductors 140, 142 and 144, 146 can nevertheless be led out of the housing 126, the adjustable section 130 in particular has a corresponding flexible material, preferably made of foam, on its end face, as can be seen from the Fig. 8 results.

[0055] The Fig. 9 bis 14 Further embodiments of restraint devices can be found in the description. These relate to those that originate from the housing 126 or the sections 128, 130. Essentially, these are embodiments of the restraint devices 178, 180, 182, 184 of the adjustable section 130 or of the restraint devices 186, 188 of the stationary section 128.

[0056] In the Fig. 9 and 10 A spring-like element 282, 284 extends along each of the hook-shaped upper surfaces 182, 184, between which and the upper surface 182, 184 of the leg 178, 180 the first connection 148 can be clamped, as can be seen from the Fig. 10 results.

[0057] According to one embodiment of the Fig. 11 A gripping device comprising two legs 290, 292 and 294, 296 respectively extends along each longitudinal side surface of the slide 113, between which a through node, i.e., in the exemplary embodiment the first connection 148, is clamped in order to then carry out the welding of the second conductor.

[0058] However, restraint devices can also be attached to the stationary section 128 of the housing 126, according to the designs of the Fig. 9 bis 11 exit. Thus, spring-like clamping elements 298, 300 are assigned to the hook-shaped projections 186, 188, between which and the upper surfaces of the projections 186, 188 a through node can be clamped, as is the case with the Fig. 13 can be seen.

[0059] Fig. 14 A gripping device is seen as a restraint device according to the Fig. 11in front, i.e. each pair of mutually pivotable legs 302, 304 and 306 as well as another invisible leg are adjustable towards each other in order to clamp a through knot.

[0060] It should be noted that the method according to the invention is also feasible if more than two connections are to be welded, i.e., if more than the first and second lines are to be welded. The holding device can therefore be designed to accommodate several connections or through-joints. It would also be possible to provide more than one holding device to accommodate connections and keep them away from the compression chamber.

Claims

1. Method for electrically conductive connecting of first electrical conductors (140, 142) and second electrical conductors (144, 146) preferably twisted therearound in a compression chamber (121) variable in cross-section, in particular in height and width, and having at least one lateral slide (113), a sonotrode (114) and a counter electrode (115), by means of ultrasonic welding, wherein bare ends of the first electrical conductors initially being inserted into the compression chamber and welded by means of ultrasonic effect into a first connection (148) and then after removal of the first connection from the compression chamber bare ends of the second electrical conductors being inserted thereinto and welded by means of ultrasonic effect into a second connection, characterized in that, before welding of the second connection the first connection (148) is passed to a retaining device (150, 152, 156, 158, 160, 162, 164, 166, 168, 178, 180, 186, 188).

2. The method according to Claim 1, wherein, during the welding, the compression chamber (121) is surrounded by a housing (128, 130), in particular a sound protection housing, characterized in that, as the retaining device (150, 152, 156, 158, 160, 162, 164, 166, 168, 178, 180, 186, 188), such a retaining device is formed, which is provided within the housing.

3. The method according to Claim 1 or 2, characterized in that, the retaining device (150, 152, 156, 158, 160, 162, 164, 166, 168, 178, 180, 186, 188) is formed in or on the lateral slide (113), the counter electrode (115) or, in the case of presence of a housing, on or in the housing interior.

4. An arrangement for materially bonded connecting of first conductors (140, 142) into a first welded connection and of second conductors (144, 146) into a second welded connection by means of ultrasonic, comprising a compression chamber (121) limited by at least one lateral slide (113), a sonotrode (114) and a counter electrode (115) and preferably surrounded during welding by an in particular sound-insulating housing (126, 128, 130), characterized in that, a welded connection retaining device (150, 152, 156, 158, 160, 162, 164, 166, 168, 178, 180, 186, 188) for receiving the first welded connection (148) made by welding bare ends of the first conductors (140, 142) during welding of bare ends of the second conductors (144, 146) into the second welded connection, the welded connection retaining device (150, 152, 156, 158, 160, 162, 164, 166, 168, 178, 180, 186, 188) being provided in or on the lateral slide (113) or the counter electrode (115) or, if the housing (126, 128, 130) is present, extending from its interior or from an element (134) closing the housing on the bottom, the welded connection retaining device (150, 152, 156,158,160, 162, 164,166, 168, 178, 180, 186, 188) being designed as at least one element from the group recess, projection, bar, hook, clamping device, gripping element, spring, holddown.

5. The arrangement according to Claim 4, characterized in that, in the upper side (1113) of the lateral slide (113) located at a distance from the bottom surface of the compression chamber (121), a recess (150, 152, 156, 158, 160, 162, 164) is formed as welded connection retaining device.

6. The arrangement according to Claim 5, characterized in that, in a cross section perpendicular to the front surface of the lateral slide (113) delimiting the compression chamber (121), the recess (150, 152, 156, 158, 160, 162, 164) has a geometry in the form of a triangle, in particular a non-isosceles triangle, a rectangle, a segment of a circle, in particular a semicircle, or one or more combinations thereof.

7. The arrangement according to at least one of Claims 5 to 6, characterized in that, the recess is formed as an undercut (164).

8. The arrangement according to Claim 4, characterized in that, above the upper side (1113) of the lateral slide (113), a protrusion (166, 168), which is preferably rectangular or L-shaped in cross section, protrudes, which, on the compression chamber-side transitions in particular flush into the front surface delimiting the compression chamber (121).

9. The arrangement according to Claim 4, characterized in that, in the front surface (172) of the counter electrode (115) facing the lateral slide (113), a recess (176) is formed as the welded connection retaining device, or a protrusion (174), as welded connection retaining device, starts from the front surface.

10. The arrangement according to Claim 9, characterized in that, the protrusion (174) of the counter electrode (115) transitions flush into the surface of the counter electrode delimiting the compression chamber, as a section of same.

11. The arrangement according to one of Claims 4 to 10, characterized in that, the housing (126) comprises a first section (128), in particular a stationary first section, and a second section (130) which is adjustable with respect to said first section and which, during the welding, preferably adjoins said first section, and in that, starting from the first or the second section is at least one protrusion (178, 180, 182, 184, 186, 188), in particular hook- or bracket-shaped, as the welded connection retaining device.

12. The arrangement according to Claim 11, characterized in that, starting from the first or the second section (128, 130) of the housing (126) are two mutually spaced welded connection retaining devices (178, 180, 182, 184, 186, 188), which, when the housing is closed, extend on opposite sides of the compression chamber (121).

13. The arrangement according to Claim 4, characterized in that, the arrangement comprises more than one welded connection retaining device (150, 152, 156, 158, 160, 162, 164, 166, 168, 178, 180, 186, 188).