EP2589052B1 - Actuator - Google Patents

Abstract

An electromagnetic actuation device with an actuation element, which can be adjusted relative to a stator on the basis of a magnetic actuation force which can be generated by the stator, wherein the stator has a coil winding, the winding wire of which is guided to a contact element bent at a bending region and is fixedly and electrically conductively connected to the same, wherein the contact element (5) has a depression geometry (9) in a bending region (7), which shortens a bending path of the winding wire (4) and through which the winding wire (4) passes.

Description

The invention relates to an electromagnetic actuating device with a, in particular elongate, preferably permanent magnet means having, adjusting element which is adjustable relative to the stator due to a stator generated by a magnetic actuating force, wherein the stator comprises a coil winding, the winding wire to a bent portion at a bending contact element guided and connected to this fixed and electrically conductive.

Such devices are well known and are used for a variety of purposes. The basic principle is that a usually piston-shaped control element, which has an engagement region for the intended setting task, is guided in a generally magnetically conductive housing as an anchor between a stationary core region and a bearing element acting as a yoke and by means provided approximately in the core area Electromagnet (coil winding) can be actuated.

In the DE 20 2006 011 904 U1 a generic electromagnetic actuator is shown with essential elements. In the known adjusting device, the stator (coil device) comprises a plastic carrier, on which a coil winding is wound. The winding wire of the coil winding is encapsulated by the plastic carrier and led out of this. For contacting contact elements with the winding wires they are first electrically connected with their end portions with the contact elements, whereupon the latter are bent over, such that their respective end portion extends approximately parallel to the longitudinal axis of the plastic carrier.

When bending the contact elements acts on the respective winding wire tensile stress, if this process technology in the winding process not enough relief (stomach) can be given, which can convert the winding wire in bending the associated contact element in length. This in turn can lead to a material weakening and in extreme cases to a tearing off of the winding wire.

For further prior art, reference is made to the DE 199 36 425 A1 as well as the JP 2006 019315 A ,

Based on the aforementioned prior art, the present invention seeks to provide an electromagnetic actuator with at least one bent contact element, wherein damage to the contact element fixed winding wire when bending the same is reliably avoided. Preferably, it should not be necessary to relieve the winding wire, which is preferably formed as a copper enamel wire, in terms of process technology in the winding process.

This object is achieved with an electromagnetic actuator according to claim 1.

Advantageous developments of the invention are specified in the subclaims.

The invention avoids an undue tension on the, in particular designed as a copper wire, winding wire by providing a recess geometry in the contact element through which the winding wire is passed, and thus must extend only over a shorter path than when the winding wire, as in the Technique, would be guided along a non-recessed outer surface of the contact element. Due to the invention, therefore, the distance to be bridged by the winding wire in an area between the beginning and the end of the bending region is shortened compared to a variant of the contact element without such a recess, ie in comparison to known from the prior art contact elements, in which Winding wire at the outer radius of the bending region, is guided or arranged adjacent to the contact element. In contrast to the stand In the art, the winding wire preferably has no continuous arc shape due to the recess geometry in the bending region of the contact element. Preferably, the recess geometry is dimensioned so that the winding wire undergoes no or at most a slight tensile stress in the bending process, in which the contact element is preferably bent by about 90 °, more preferably such that its end portion, at least approximately, parallel to the adjustment axis of the actuating element. Particularly preferably, a plastic deformation of the winding wire during the bending process of the contact element is completely avoided by the provision of a suitably designed recess geometry, which in turn leads to the avoidance of a reduction in strength or even a tear of the winding wire. Under a recess geometry is understood in the direction of thickness extension of the contact element and thus both perpendicular to the width extension and perpendicular to the longitudinal extent of the contact element extending geometry, due to which the winding wire occupies a smaller radius of curvature, ie a shorter distance must bridge than an imaginary, the recess geometry spanning outer envelope contour of the contact element, or as the outer surface laterally adjacent to the recess geometry.

There are various possibilities with regard to the specific design of the indentation geometry. According to a first alternative, the recess geometry may be formed as a recess pocket, that is as a preferably trough-like, a bottom surface having recess whose bottom is arranged perpendicular to the longitudinal extent of the contact element in the direction of its thickness extension downwards, ie preferably in the direction of stator. Alternatively to a introduced into the contact element, having a bottom recess, the recess geometry may be formed as a breakthrough, so as a bottomless recess geometry. A third possibility is to form the recess geometry as a recess open at the edge, which extends from one longitudinal side of the contact element at least to the middle of the recess geometry, preferably (slightly) beyond. This depression can be made with soil, eg by forming, or without soil, preferably by punching.

Preferably, the axial extent of the recess geometry is selected from a value range between 1.5 mm and 3.5 mm, preferably between 2.4 mm and 2.8 mm. In the case of the formation of the recess geometry as a breakthrough or depression pocket, its width extension is preferably selected from a value range between 0.5 mm and 2.5 mm, preferably between 1.0 mm and 1.5 mm. In the case of the formation of the recess geometry as a breakthrough is their depth extension with advantage of the thickness extension of the preferably tab-shaped contact element. In the case of the formation of the recess geometry as a recess pocket, the depth of the recess geometry is preferably selected from a value range between 0.1 mm and 1.0 mm, preferably between 0.2 mm and 0.5 mm.

In general, the length extension, i. the axial extent of the contact element is preferably greater than the width of the contact element, which in turn is preferably greater than the thickness of the contact element.

In a further development of the invention it is advantageously provided that the winding wire, at least in a winding wire (viewed from the exit from the carrier) located in front of the depression and adjacent to the depression area and in a lying after the recess geometry and adjacent to the recess geometry area an outwardly directed, ie facing away from the longitudinal axis of the actuator away surface of the contact element extends to obtain an abbreviation by the recess geometry.

In particular, when the recess geometry is formed as a breakthrough, or the depth of the recess pocket is selected to be correspondingly large, the winding wire extends in the bending region, in at least one section in a straight line, for example, between the two axial end portions of the recess geometry. In the case of the formation of the recess geometry as a recess pocket, the winding wire can also be straight in two axial areas, namely in a first area between an axial end of the recess geometry and a support area in which the winding wire reaches the bottom of the recess pocket and in a second area between the bottom-side support area the winding wire in the recess pocket and the other axial end of the recess pocket.

It is particularly expedient if the recess geometry is arranged centrally with respect to the width of the contact element or at least extends to the width center of the contact element from the lateral direction, preferably beyond. In this way, the winding wire, at least approximately centrally with respect to the width extension of the contact element can be arranged to extend.

It is particularly useful if the recess geometry has a greater length than width extension. Preferably, the dimple geometry should be just sized so that the winding wire does not receive too much relaxation to avoid damage, particularly strain hardening, from engine vibrations and resulting cracking.

It is particularly expedient to design the recess geometry in such a way that the bending path of the winding wire, ie the length of the winding wire in the bending region is shorter than the (actual) course of the winding wire lying on the surface of a contact pin without recess geometry. In other words, the length extension of the winding wire in the bending region is preferably shorter than the longitudinal extent of an outer envelope profile (spanning the depression geometry) of the contact element in the bending region. Preferably, the length extension of the winding wire in the bending region is shorter than a neutral fiber of the contact element in this bending region, in each case measured between the same axial starting and ending point.

With regard to a possible fixation of the winding wire on the contact element, it is preferred if the winding wire is fixed exclusively in an end section of the contact element arranged after the bending region, ie not in a region in front of the bending region. Particularly preferably, the winding wire is fixed by welding, particularly expediently by inductive welding or soldering, in particular induction soldering or platelet soldering on the contact element. It is even more preferable if the winding wire between a metal plate connected to the contact element, in particular by welding or soldering, in particular induction welding or soldering, preferably induction welding or soldering, preferably flake welding or soldering, and the contact element is received.

Particularly low cost, the recess geometry may be formed by punching, wherein in the case of forming a recess pocket preferably only a deformation of the contact element is achieved, whereas in the case of the formation of the recess geometry as, in particular central, breakthrough material is punched from the contact element.

To further improve the longevity of the adjusting device, it is preferred if the depression geometry is provided with a radius in at least one transition region, preferably in both transitional regions, to the contact element surface which is not recessed with respect to the depression geometry in order to reliably avoid damage to the winding wire.

Particularly preferably, the contact element is designed as a kind of tab, which is held in a carrier body, preferably by encapsulation. The tab leaves the carrier body preferably in the radial direction and is bent outside the carrier by 90 ° and thus extends endwise in the axial direction.

It is particularly preferred if at least two winding wire ends are each fixed to a contact element having a recess geometry formed as described above in an electrically conductive manner, in particular by resistance welding or soldering.

In order to achieve a specific, in particular with respect to the width of the contact element, central arrangement of the winding wire, a winding wire guide geometry is provided in development of the invention on the contact element, preferably by reshaping the same, which defines or specifies a certain position or a position range of the winding wire, preferably to ensure the most accurate positioning in the adjacent fixation area.

It is particularly useful in this case, if this wire guide geometry is simultaneously formed as a fixing geometry, which fixes the winding wire non-positively, preferably positively, in particular by clamping, in a certain position on the contact element. In addition to this fixing geometry, at least one further fixing means is preferably provided, in particular a welding region in which the winding wire is welded or soldered, in particular inductively, to the contact element, for example by so-called flake welding or plate soldering, in which a metal flake is adjacent to the winding wire and / or placed at a distance from the fixing geometry on the winding wire and the contact element and with this, in particular inductively, welded or soldered.

It is particularly expedient if the winding wire guide geometry, preferably not, but not necessarily, provided in the actual welding area no winding wire guide geometry, but there the winding wire preferably rests there on a flat outer surface of the contact element, the welded wire preferably formed as a fixing geometry ,

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings.

Fig. 1

eine schematische Ansicht einer elektromagnetischen Stellvorrichtung,

Fig. 2a

in einer ausschnittsweisen Darstellung ein Kontaktelement mit einer als mittiger Durchbruch ausgebildeten Vertiefungsgeometrie,

Fig. 2b

eine Längsschnittansicht der Darstellung gemäß Fig. 2a,

Fig. 3a

die Vertiefungsgeometrie gemäß den Fig. 2a und 2b im gebogenen Zustand des Kontaktelementes,

Fig. 3b

eine Längsschnittansicht der Darstellung gemäß Fig. 3a,

Fig. 4a

ein alternatives Ausführungsbeispiel einer Vertiefungsgeometrie, bei welchem diese als seitliche Aussparung ausgebildet ist,

Fig. 4b

eine Längsschnittansicht der Darstellung gemäß Fig. 4a,

Fig. 5a

das Kontaktelement gemäß Fig. 4a im gebogenen Zustand,

Fig. 5b

eine Längsschnittansicht der Darstellung gemäß Fig. 5a,

Fig. 6a

ein alternatives Ausführungsbeispiel der Vertiefungsgeometrie als Vertiefungstasche,

Fig. 6b

eine Längsschnittansicht der Darstellung gemäß Fig. 6a,

Fig. 7a

die Darstellung des Kontaktelementes gemäß Fig. 6a im gebogenen Zustand,

Fig. 7b

eine Längsschnittansicht der Darstellung gemäß Fig. 7a,

Fig. 8

eine Führungsgeometrie zur Führung des Wicklungsdrahtes, wobei als Führungsgeometrie eine wannenartige Geometrie gewählt ist, in der der Wicklungsdraht mit Seitenabstand angeordnet ist und die Wanne mit einem Klebstoff ausgefüllt ist,

Fig. 9

eine alternative Darstellung einer als Fixierungsgeometrie ausgebildeten Wicklungsdrahtführungsgeometrie, bei der der Wicklungsdraht zwischen zwei Abschnitten des Kontaktelementes klemmend aufgenommen ist, und

Fig. 10

eine Darstellung einer alternativen als Fixierungsgeometrie ausgebildeten Führungsgeometrie, bei welcher der Wicklungsdraht in einer Art Wellengeometrie des Kontaktelementes klemmend aufgenommen ist.

These show in:

Fig. 1

a schematic view of an electromagnetic actuator,

Fig. 2a

in a sectional view, a contact element with a recess formed as a central aperture recess geometry,

Fig. 2b

a longitudinal sectional view of the illustration according to Fig. 2a .

Fig. 3a

the dimple geometry according to the Fig. 2a and 2b in the bent state of the contact element,

Fig. 3b

a longitudinal sectional view of the illustration according to Fig. 3a .

Fig. 4a

an alternative embodiment of a recess geometry in which it is formed as a lateral recess,

Fig. 4b

a longitudinal sectional view of the illustration according to Fig. 4a .

Fig. 5a

the contact element according to Fig. 4a in the bent state,

Fig. 5b

a longitudinal sectional view of the illustration according to Fig. 5a .

Fig. 6a

an alternative embodiment of the recess geometry as a recess pocket,

Fig. 6b

a longitudinal sectional view of the illustration according to Fig. 6a .

Fig. 7a

the representation of the contact element according to Fig. 6a in the bent state,

Fig. 7b

a longitudinal sectional view of the illustration according to Fig. 7a .

Fig. 8

a guide geometry for guiding the winding wire, wherein a trough-like geometry is selected as the guide geometry, in which the winding wire is arranged with lateral spacing and the trough is filled with an adhesive,

Fig. 9

an alternative representation of a trained as fixing geometry winding wire guide geometry in which the winding wire between two sections of the contact element is received by clamping, and

Fig. 10

a representation of an alternative designed as a fixation geometry guide geometry, in which the winding wire is received by clamping in a kind of shaft geometry of the contact element.

In the figures, like elements and elements having the same function are denoted by the same reference numerals.

In Fig. 1 an electromagnetic adjustment device 1 is shown, which interacts with an actuating partner, not shown, for example, a camshaft Hubumschaltung, actuated. The electromagnetic actuator comprises a stator 2 with a coil winding 3, wherein an unillustrated actuator (armature) is guided axially adjustable inside the actuator centrally. To adjust the control element, the coil winding 3, more precisely, the winding wire 4 is energized. For contacting the winding wire 4 of these two ends is electrically connected to a respective tab-shaped contact element 5, which are led out radially from a plastic carrier 6 and are bent outside of the carrier 6 by about 90 ° in a bending region 7. The winding wire extends on the contact elements 5 on an outwardly directed surface 8 of the respective contact element 5 and is guided in the direction of its longitudinal extent by a recess geometry 9 which is to be explained later and is arranged in the bending region, which shortens the bending path of the winding wire in comparison to one Biegeweg without such a recess geometry.

The contact elements 5 rest on an elastomeric pad 10, preferably a silicone pad, for reasons of vibration damping, wherein the elastomeric pad 10 has an inner side or an inner surface of the respective contact element connects to the carrier 6. As it turned out Fig. 1 results in the winding wire 4 in about axparallen end portion of the contact element with this firmly connected, for example by, preferably inductive, welding or soldering.

As it turned out Fig. 1 further results, a metallic core portion 12 is received in a central blind hole 11 within the carrier. In a guide tube, not shown, the adjusting element, also not shown, is added.

The following are based on the Fig. 2a to 7b different embodiments of possible dimple geometries shown on contact elements, wherein it is preferably in the contact elements 5 as in Fig. 1 arranged contact elements 5 is, in each case in the figures shown on the left, the contact element 5 is shown before bending, so as exclusively in the radial direction extending contact element, while each right figures represent the bent end position or the final assembly.

In the Fig. 2a to 3b is a first embodiment of a contact element 5 for an exemplary in Fig. 1 shown electromagnetic actuator 1 shown. Evident is the metallic, laschen- or platelet-shaped contact element with a thickness extension d, preferably from a range between 0.15 mm and 0.4 mm. The width b is preferably between 2.0mm and 4.0mm. It can be seen that at the outwardly directed, ie over a large part of their surface extension in the final assembled state in the radial direction outwardly facing surface 8 centrally with respect to the width extension, a winding wire 4 extends, the sake of clarity in the Fig. 2b and 3b is arranged at a distance from the surface 8, but in reality, of course, rests on this or runs directly on this. It can also be seen that the winding wire 4 is guided axially through a recess geometry 9, which in the embodiment according to FIGS Fig. 2a to 3b is formed as arranged with edge distance breakthrough 13, which is preferably made by punching. The dimple geometry 9 has a greater length than the width dimension. The depth of the recess geometry corresponds, since this In the case of forming the recess geometry as later to be explained, preferably produced by forming, recess pocket, the depth extent of the recess geometry may also be less than or greater than the thickness extension d of metallic contact element 5.

From the representations according to the Fig. 3a to 3b it can be seen that the recess geometry 9 is arranged in the bending region 7, in which the contact element 5 is bent. The bending region is understood to be the region between the beginning and the end of the curvature, that is to say the curved region which connects the two mutually perpendicularly arranged sections 14, 15 of the contact element 5 (with a radius).

In Fig. 3b is shown schematically the course of the winding wire 4 in the bending region 7. By the recess geometry 9, the bending path of the winding wire 4 is shortened compared to an embodiment without recess geometry 9. In the embodiment shown, the winding wire 4 extends between the axial beginning and the axial end of the recess geometry 9 in a straight line.

To protect the winding wire 4, the recess geometry 9 is provided in the transition region to the non-recessed surface 8 with a radius 16. It is also an embodiment conceivable in which such a radius is provided only at the axial, opposite side surfaces in the transition region to the surface 8, ie only in the region with which the winding wire 4 is in contact.

Fig. 4a to 5b show an alternative embodiment of a contact element 5 with recessed geometry, wherein to avoid repetition in the following essentially addresses the differences from the preceding embodiment. With regard to similarities, reference is made to the above embodiment. In contrast to the above embodiment, the recess geometry 9 is not arranged with edge distance, but extends laterally from the outside to over the wide center of the Contact element 5 out. The recess geometry 9 is formed in the embodiment shown as a lateral, preferably produced by punching, recess 17, wherein the recess 17 does not necessarily have to be formed as punched out as shown, but it is conceivable that also produced by forming, downwardly offset bottom realized in the manner of a bag.

As is clear from the Fig. 5a and 5b results in the winding wire 4 in the final assembly state in the bending region 7 in a straight line.

In the following, a further embodiment of a contact element 5 with winding wire 4 and recess geometry 9 based on Fig. 6a to 7b described. In order to avoid repetition, differences to the preceding embodiments are essentially discussed. With regard to the similarities, reference is made to the preceding figures plus description of the figures.

In contrast to the preceding embodiments, the recess geometry 9 in the embodiment according to the Fig. 6a to 7b formed as a recess pocket 18, which in contrast to a breakthrough has a bottom 19 and thus a bottom surface. The axial extent of the recess geometry 9 corresponds to 4.0 mm in the embodiment shown (in the unbent state). It can be seen that the recess pocket 18 is arranged with edge distance to the longitudinal sides of the contact element 5, wherein an embodiment analogous to the embodiment according to FIG Fig. 4a to 5b can be realized, in which the recess pocket 18, at least up to a longitudinal edge, alternatively extends to both longitudinal edges. The depth of the recess pocket 18 corresponds in the embodiment shown approximately half the thickness of the contact element 5, which leads in the embodiment shown to the fact that the winding wire 4 - in contrast to the preceding embodiments - the contact element 5 in the bending region 7, here approximately centrally touched, As a result, the winding wire 4 in two axially adjacent, here axially spaced regions 20, 21 has a straight course, the through a bent portion in which the winding wire 4 abuts the bottom 19 of the recess geometry is connected.

In the Fig. 8 to 10 different embodiments of contact elements 5 are shown, all of which are equipped with a winding wire guide geometry 22 to position the winding wire centered here with respect to the width center of the contact element 5. Preferably, the winding wire guide geometry 22 is in a region between the in the Fig. 8 to 10 recess geometry, not shown, and the free end of the contact element, preferably either before or after a welding or soldering area, in which the winding wire is fixed electrically conductively to the contact element 5 by welding or soldering. Additionally or alternatively, a bonding, in particular with an electrically conductive adhesive is conceivable.
The winding wire guide geometry 22 is in accordance with the contact element 5 Fig. 8 , which is shown in a cross-sectional view, formed as a recess or sections U-shaped pocket, in which the winding wire 4 is arranged at a distance from the pocket sides. The pocket 23 is filled with adhesive 24 for additional fixing of the winding wire 4.

In the embodiment according to Fig. 9 in which the contact element 5 as in the embodiments according to FIGS. 8 and 10 is shown in a cross-sectional view extending perpendicular to the longitudinal extent, the winding wire guide geometry 22 is designed as a fixing geometry 25 for additional fixing of the winding wire 4. For this purpose, the contact element 5 is slotted in an axial section and the inwardly facing ends 26, 27 are adjusted downwards and take the winding wire by clamping between them. In a region in front of the fixing geometry 25, the contact element 5 is formed without the slot shown.

In the embodiment according to Fig. 10 the winding wire guide geometry 22 is also formed as a fixing geometry 25 by the contact element 5 has been converted into a waveform, wherein the winding wire 4 is received in a wave recess by clamping.

By in the Fig. 8 to 10 shown winding wire guide geometries 22 ensures that the winding wire 4 in the axially adjacent fixation area, in particular welding or soldering area, optionally adhesive area, is located at the desired fixing position.

reference numeral

1

electromagnetic adjustment device

2

stator

3

coil winding

4

winding wire

5

contact element

6

carrier

7

bending area

8th

surface

9

groove geometry

10

elastomeric pad

11

blind

12

core area

13

breakthrough

14

section

15

section

16

radius

17

recess

18

depression pocket

19

ground

20

Area

21

Area

22

Winding wire guide geometry

23

bag

24

adhesive

25

fixed geometry

26

The End

27

The End

Claims (14)

1. Electromagnetic actuating apparatus (1) having a stator (2) and an actuating element that can be moved relative to a stator by a magnetic actuating force which can be produced by the stator, wherein the stator comprises a coil winding (3) and a contact element (5), and a winding wire (4) of the coil winding is passed to the metallic contact element which is curved in a bending area, and said wire is fixedly electrically conductively connected thereto,
   characterized in that
   in the bending area (7), the contact element (5) has a depression geometry (9) which shortens the bending path of the winding wire (4) and through which the winding wire (4) passes,
   through which the winding wire is passed axially between an axial beginning and an axial end of the depression geometry in order to shorten the distance to be bridged by the winding wire in an area between the beginning and the end of the bending area,
   wherein the axial extension of the depression geometry extends in the longitudinal direction of the contact element.
2. The actuating apparatus according to Claim 1,
   characterized in that
   the depression geometry (9) is implemented as a depression slot (18) or as a breakthrough (13) or as a recess which is open around its edge.
3. The actuating apparatus according to any one of Claims 1 or 2, characterized in that
   the winding wire (4), at least in an area located before the depression geometry (9) and adjoining the depression geometry (9), and in an area located after the depression geometry (9) and adjoining the depression geometry (9), extends on an outward-directed surface (8) of the contact element (5).
4. The actuating apparatus according to any one of the preceding claims, characterized in that
   the depression geometry (9) is either arranged centrally with respect to the lateral extension of the contact element (5) or it extends from the outside perpendicular to the longitudinal extension of the contact element (5), at least as far as the centre of the contact element (5).
5. The actuating apparatus according to any one of the preceding claims, characterized in that
   the longitudinal extension of the depression geometry (9) is greater than its lateral extension.
6. The actuating apparatus according to any one of the preceding claims, characterized in that
   the bending path of the winding wire (4), measured between the same axial starting and end point, is shorter than the longitudinal extension of an outer envelope contour of the contact element (5) spanning across the depression geometry in the bending area and/or is shorter than a neutral fibre of the contact element (5) in the bending area (7).
7. The actuating apparatus according to any one of the preceding claims, characterized in that the winding wire (4) is fixedly connected to the section of the contact element (5), which projects beyond a substrate body, exclusively in an end section which is arranged after the bending area (7).
8. The actuating apparatus according to any one of the preceding claims, characterized in that
   the depression geometry (9) is produced by punching, in particular deformation punching or stamping.
9. The actuating apparatus according to any one of the preceding claims, characterized in that
   the depression geometry (9) has a radius (16) in the transition region to the non-depressed contact element surface.
10. The actuating apparatus according to any one of the preceding claims, characterized in that
    the contact element (5) is implemented as a tab.
11. The actuating apparatus according to any one of the preceding claims, characterized in that
    both ends of the winding wire are electrically conductively attached to one contact element (5) each, which comprises the depression geometry (9).
12. The actuating apparatus according to any one of the preceding claims, characterized in that
    a winding wire guiding geometry (22) is provided on the contact element (5) for positioning the winding wire (4).
13. The actuating apparatus according to Claim 12, characterized in that
    the winding wire guiding geometry (22) is implemented as a fixing geometry (25) which secures the winding wire (4) with a force fit, preferably with a positive fit.
14. The device according to any one of Claims 12 or 13, characterized in that
    the winding wire guiding geometry (22) is arranged upstream or downstream of a fixing area in which the winding wire (4) is welded or soldered, preferably inductively, to the contact element (5).

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