Contact hook and contact device for providing electrical contact with winding device of electric machine, and method for producing contact device

Abstract

The invention relates to a contact hook for providing electrical contact with a winding device of an electric machine, comprising: a fastening section for fastening to the electric machine, the fastening section providing a first contact surface for an electric resistance welding electrode; and a hook section adjoining the fastening section, the hook section providing a second contact surface for the resistance welding electrode, the hook section being designed and arranged in such a way that, in a first assembled state, the hook section together with the fastening section forms a groove for receiving a wire connected to the winding device, and in the first assembled state, the hook section provides a second contact surface for the resistance welding electrode. In a first assembled state, the free end of the hook section forms a groove opening for inserting the wire into the groove at a distance from the fastening section, and in a second assembled state, the free end of the hook section rests on the fastening section in a manner of closing the groove opening in such a way that the first contact surface and the second contact surface run parallel to each other; the invention also relates to a contact device for providing electrical contact with a winding device of an electrical machine and to a method for producing a contact device.

Description

Technical Field

[0001] The invention relates to a contact hook for providing an electrical contact with a winding arrangement of an electric machine and to a contact arrangement. The invention also relates to a method for producing a contact arrangement. Background Art

[0002] The active parts of an electric motor mainly consist of a stationary part (stator) and a moving part (rotor). In the stator there is a conductor which generates a rotating magnetic field by passing current through it in a suitable manner. Through mutual electromagnetic interaction with the rotor, the stator exerts a force on the rotor, which causes the rotor to move. Different machine principles are suitable for this purpose. The most common ones are asynchronous motors (ASM for short), permanent magnet synchronous motors (PSM for short) and separately excited synchronous motors (FSM for short).

[0003] The separately excited synchronous motor (FSM) is a magnet-free alternative to the permanent magnet synchronous motor (PSM) used to power electric vehicles. The magnets in the rotor of the PSM are replaced by current-carrying copper windings that act as electromagnets to generate the rotor magnetic field that creates torque.

[0004] The copper winding of the rotor consists of standard enameled wire. The winding is wound on the rotor poles. For reasons of efficiency and power, the aim is to wind as many turns as possible into the available cross section. For this reason, orthogonal loop winding is the goal, since this winding achieves the highest possible packing density due to the 60° stagger between the wires in the two layers.

[0005] The winding body of the FSM rotor consists of several parts. The central component is a laminated core mounted on a shaft. After winding, the copper wire runs in the slots of the laminated core. In order to deflect the wire roll in the area of ​​the winding head, two star disks are installed on the end sides of the laminated core. The star disks have a contour for targeted, mechanical support of the wire coils. The star disks can be made of plastic as a whole. In order to increase the strength, a metal core can also be used. In this type of component, the base body made of metal is encapsulated with plastic.

[0006] The winding of the rotor consists of a concentrated number of coils, which are arranged around the poles. The rotor usually includes six poles, but there can also be other numbers of poles, for example, eight poles. The design is based on a trapezoidal winding structure in order to maximize the use of copper to fill the space between the poles. As a result, a high copper filling degree and thus a high efficiency and high power density of the motor can be achieved. All the sub-windings shown are connected in series one after another using a continuous wire.

[0007] The challenge in the trapezoidal winding structure is that the last turn of the pole winding never ends at the bottom of the yoke. However, the changeover between the poles is always only possible at the bottom of the yoke. The first wire turn is against the bottom of the yoke. Subsequently, the winding is built up layer by layer. The last wire turn ends at the top of the pole shoe and not at the bottom of the yoke. However, the changeover between the poles is always only possible at the bottom of the yoke. Since the pole change can only be carried out at the bottom, the wire must be led back to the yoke. From the perspective of the rotor, this return is carried out radially from the outside to the inside in the direction of the axis. Only then is the connection of the individual poles achieved at the yoke.

[0008] There are various solutions for routing the wire from the pole piece back to the yoke:

[0009] On the one hand, there is a solution for recirculation via special contours in the star disk. The star disk supports the wire and enables a diagonal run over the winding head. German patent application DE 10 2020 118944 describes a precise embodiment.

[0010] On the other hand, the wire can be fed back from the pole shoe to the yoke by means of a special winding concept. Targeted gaps or notches in the winding support the wire during the feeding back. German patent document DE 102021 101 814 describes a precise embodiment.

[0011] In both variants, the last turn is positioned directly on the yoke.

[0012] German patent application DE 10 2021 122 066 describes an alternative for returning wires. The core idea is to integrate the busbar used for conductor return in the trapezoidal winding into the star disk. For example, the busbar is cast into the star disk by an injection molding method. As a result, the conductor is no longer wound via a standard wire as in all other windings, but the conductor is returned from the pole shoe to the yoke via the busbar. The return function is therefore transferred to the star disk. The busbar is embedded in the injected plastic ("molding"). At both ends of the busbar, there are contact elements that establish a connection between the winding and the busbar, respectively. The star disk can also include a metal core. In addition, this molding also includes the functions of wire guiding and wire supporting. The outer contour defined in a targeted manner enables a robust winding process. As a transition between the wound wire roll and the busbar, a fork-shaped contact element, also referred to as a fork contact, is used.

[0013] In particular, when the rotor is wound automatically (for example using needle winding technology), this fork-shaped contact causes problems, because the wire cannot be inserted automatically easily. The reason for this is the tensile forces acting on the outside of the star disk, especially in this position.

[0014] In order to make the contact as mechanically stable as possible, the wire must always be located in the bottom of the groove of the fork-shaped contact. When winding, the wire is subjected to the so-called wire tension acting in the direction of the wire. This force always produces a lead-out contour at the outlet of the wire from the winding needle, which corresponds to a circular arc with a radius related to the wire tension. In order to be able to place the wire reliably in the bottom of the groove, the wire must be placed in a forced positioning (Zwangslage), in which the wire lead-out angle between the winding needle and the wire led out of it is greater than 90°. However, this angle leads to unacceptably high wire tension, which may damage the wire or even cause the wire to break. This forced positioning requires that the fork-shaped contact is axially higher than the supporting contour. However, this additional structural space is magnetically inactive and reduces the power density of the drive device.

[0015] DE 10 2017 214 776 A1 describes a method for producing a rotor of an electric machine with a contactless power transmission system, wherein a winding head cover is arranged on one end side of the laminated core of the rotor. A secondary unit (SEC) of the power transmission system is integrated into the winding head cover, and thus after the winding head cover is arranged, the secondary unit (SEC) is indirectly held on the rotor via the winding head cover. The excitation winding of the rotor is connected to a contact element of a rectifier of the secondary unit, wherein the contact element is configured as a winding hook, which is inserted into a rectifier circuit board of the rectifier via a rear fastening section. The hook section of the winding hook extends in the axial direction of the rotor.

[0016] CN 207117332 U discloses a rotor assembly with a winding arrangement, in which a coupling portion of the winding arrangement is fastened to the inner side of a hook-shaped piece by ultrasonic welding, and the hook-shaped piece is fastened to a commutator unit.

[0017] DE 10 2015 001 096 A1 relates to a stator of an electric motor, comprising: a multi-phase stator winding, each phase of the stator winding having a plurality of coils, each of which has a first coil end and a second coil end; and a switching unit, the switching unit having a plurality of contact wires, for connecting the coil ends respectively assigned to the contact wires, the contact wires having a plurality of bent contact hooks, the contact hooks having wire legs that are spaced apart from each other to form a connection opening, the connection opening receiving the assigned coil ends, wherein the contact wires are embodied as round wires and are flattened in the region of the contact hooks on the outer sides of the legs of the wire legs that face away from the connection opening to form a flat contact surface for a welding electrode. Summary of the invention

[0018] Against this background, the object of the present invention is to provide a device and a method which can be used to more easily produce an electric machine, in particular a separately excited synchronous machine, with high efficiency and power density. Furthermore, the electric machine should have a compact design.

[0019] This object is achieved by a contact hook having the features of claim 1, a contact device having the features of claim 7 and a method for producing a contact device having the features of claim 10. The corresponding dependent claims disclose further particularly advantageous embodiments of the invention.

[0020] It should be noted that the features described individually in the claims can be combined with each other in any technically reasonable manner (also across category boundaries such as between methods and devices) and represent additional embodiments of the invention. The description, in particular in conjunction with the drawings, additionally represents the features of the invention and describes the invention in detail.

[0021] It should also be noted that the conjunction "and / or" used here between two features and connecting the features to one another should always be interpreted as meaning that in a first design of the subject matter according to the invention only the first feature may be present, in a second design only the second feature may be present, and in a third design both the first feature and the second feature may be present.

[0022] The subject of the invention is a contact hook for providing electrical contact with a winding arrangement of an electric machine, for example a separately excited synchronous machine (FSM). The contact hook has a fastening section for fastening to the electric machine, which fastening section provides a first contact surface for a resistance welding electrode, and a hook section adjacent to the fastening section, which provides a second contact surface for the resistance welding electrode. The hook section is designed and arranged in such a way that, in a first assembled state, it forms together with the fastening section a slot for receiving a wire connected to the winding arrangement, in the first assembled state, the free end of the hook section forms a slot opening for inserting the wire into the slot in a manner spaced apart from the fastening section, wherein in a second assembled state, the free end of the hook section rests on the fastening section in such a way as to close the slot opening that the first contact surface and the second contact surface extend in a manner parallel to each other.

[0023] The hook section is understood to be an arcuate or angularly bent section for hooking the wire. The groove should be understood to be an elongated recess delimited by the hook section and the fastening section. The hook section is connected to the fastening section. The fastening section is used to fasten the contact hook to the motor, wherein this includes fastening to components of the motor (e.g., the rotor, the star disk of the rotor, the stator, etc.).

[0024] A wire is understood to be a flexible metal of elongated shape, which preferably has a circular cross section. Other cross-sectional shapes of flat wires, quadrilateral wires or profiled wires are also known.

[0025] Unlike the U-shaped or fork-shaped contact elements of the prior art which have two free legs, the hook section of the contact hook here only forms one free leg, which forms one side of the slot. The opposite side of the slot is formed by the fastening section.

[0026] Since the first contact surface and the second contact surface extend in a plane-parallel manner in the second assembled state, that is, the surfaces extend in a planar manner and parallel to one another, a parallel arrangement of the resistance welding electrodes in contact with the contact surfaces is achieved. Here, the arrangement of the welding electrodes parallel to one another means that the respective electrode longitudinal axes extend substantially parallel. This enables a compact, space-saving arrangement of electrodes for resistance welding the contact hook or the hook section to the fastening section in order to achieve an electrically conductive connection of a wire (e.g. an enameled wire coated with an electrically insulating enamel) to the contact hook.

[0027] It should be noted that within the tolerance range that is considered common by a person skilled in the art, the present invention also includes slight deviations from the exact (i.e., ideal) parallelism of the two welding electrodes and slight deviations from the exact (i.e., ideal) surface parallelism of the first contact surface and the second contact surface. This is understood to be a tolerance range of the relevant dimensions from the ideal dimensions, with a maximum deviation of + / -20%, preferably + / -10%.

[0028] Furthermore, by closing the slot opening, the second assembled state provides an additional crimping effect on the wire inserted into the slot.

[0029] In the first assembled state, the winding of the wire into the contact hook (for example by means of needle winding technology) is significantly simplified compared to the prior art, for example fork contacts, as will be explained in greater detail in this regard.

[0030] In a preferred embodiment, the first contact surface and the second contact surface are provided on the same side of the contact hook. Accordingly, the resistance welding electrodes can be guided parallel to each other from the same side and placed on the corresponding contact surfaces. This enables a more compact arrangement of the resistance welding electrodes for electrically conductively connecting the contact hook to the wire inserted into the slot. The second contact surface can be provided on the outer side of the hook section.

[0031] In a further preferred embodiment, the groove extends from the groove opening to the groove bottom in an inclined manner relative to the first contact surface. This allows the wire at the groove bottom to be lower than the first contact surface, so that in the second assembled state, although the free end of the hook section abuts against the fastening section, the hook section still extends in a parallel manner relative to the first contact surface. In addition, the inclined groove allows the wire to slide reliably into the groove and to rest stably at the groove bottom.

[0032] In an advantageous embodiment, the first contact surface additionally forms a contact surface for the wire, in order to place the wire in front of the slot opening in the first assembly state. When using the needle winding technique, the wire has a certain bending slack after being led out of the winding needle and is bent to different degrees depending on different factors, such as the wire tension. Here, the wire can slide along the first contact surface or the contact surface beside the slot opening. As a result, the wire is pre-positioned on the contact surface and the bending slack of the wire has no influence during laying. As a result, the alignment of the slot and the insertion into the slot are significantly simplified.

[0033] In a further advantageous embodiment, in the first assembly state, the groove has a uniform diameter, that is, the diameter of the groove is substantially the same from the groove opening to the groove bottom. In this way, the wire is reliably guided by the surface delimiting the groove when inserted into the groove, so that the wire is always placed in the groove bottom in the end without having to use forced positioning for this. That is, advantageously, the wire lead-out angle between the winding needle and the wire led out of the winding needle can always be less than 90°.

[0034] In a further preferred embodiment, an undercut is provided in the transition region between the fastening section and the hook section. For example, the undercut can be formed on the outside of the contact hook. In addition, the undercut reliably prevents the formation of stress cracks.

[0035] The subject matter of the invention further includes a contact device for providing an electrical contact with a winding arrangement of an electric machine or a component of an electric machine, such as, for example, a rotor, a star disk of a rotor, a stator, etc. The contact device has a contact hook according to any of the embodiments disclosed herein and a wire connecting the contact hook to the winding arrangement.

[0036] It is understood that in terms of definitions of terms related to the device and the functions and advantages of features related to the device, full reference can be made to the disclosure of similar definitions, functions and advantages of the contact hook according to the present invention, and vice versa. Therefore, in order to facilitate a more concise description, repeated explanations of the same features, their functions and advantages can be omitted, and such omission should not be interpreted as limiting any of the disclosed themes of the present invention.

[0037] In a preferred embodiment, the winding arrangement is a winding arrangement of a rotor of an electric machine, ie a rotor winding, wherein the contact hooks are attached to a star disk of the rotor and produce an electrically conductive connection to the rotor winding.

[0038] In other embodiments, the winding arrangement is a winding arrangement of a stator of an electric machine (ie a stator winding), wherein the contact hook is mounted on the stator and produces an electrically conductive connection to the stator winding.

[0039] In a further advantageous embodiment, a support contour for supporting the wire is arranged adjacent to the contact hook, wherein the contact hook does not protrude beyond the support contour in its second assembly position. This enables a more compact design of the contact device. For example, if the contact hook is mounted on the end side of the star disk of the rotor, the axial installation space required for the rotor can be reduced to a minimum, thereby increasing the power density of the electric machine, since a smaller volume of the magnetically inactive electric machine has to be tolerated.

[0040] In addition, the subject matter of the present invention also includes a method for manufacturing a contact device according to any of the designs disclosed herein. The method comprises the following steps:

[0041] - providing a contact hook according to any one of the embodiments disclosed herein in a first assembled state,

[0042] - Place the wire into the groove of the contact hook with the help of a winding needle,

[0043] - Pull the wire into the bottom of the trough,

[0044] - the second assembled state of the contact hook is produced by bending the hook section so that the free end of the hook section bears against the fastening section and the first contact surface and the second contact surface extend in parallel with one another,

[0045] - bringing the first resistance welding electrode into contact with the first contact surface,

[0046] - bringing the second resistance welding electrode into contact with the second contact surface, and

[0047] - resistance welding the hook section to the fastening section by means of a first resistance welding motor and a second resistance welding electrode in order to produce an electrically conductive connection between the wire and the contact hook.

[0048] With regard to the definitions of method-related terms and the effects and advantages of method-related features, full reference may also be made to the disclosure with regard to similar definitions, effects and advantages of the contact hook according to the invention or the contact device according to the invention, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Other features and advantages of the present invention are obtained from the following description of embodiments of the present invention, which should not be understood as limiting, and which are explained in detail below with reference to the accompanying drawings. In the drawings, it is schematically shown:

[0050] Figure 1 shows a side view of a contact hook according to an embodiment of the present invention;

[0051] Figure 2 Shows Figure 1A side view and a top view of a contact hook in order to explain a method for manufacturing a contact device according to an embodiment of the present invention;

[0052] Figure 3 Shows Figure 1 A first side view of the contact hook in a first assembled state of a contact device according to one embodiment of the present invention and a second side view of the contact hook in a second assembled state;

[0053] Figure 4 Shows Figure 3 A side view of a contact device in FIG. 1 is used to explain the resistance welding process; and

[0054] Figure 5 Shows that there is Figure 3 A perspective view of the rotor of an electric machine with a contact device in FIG. DETAILED DESCRIPTION

[0055] In the various figures, components with the same function are always provided with the same reference symbols, so that these components are usually also described only once.

[0056] Figure 1 A side view of a contact hook 10 for providing an electrical contact with a winding arrangement of an electric machine (neither of which are shown) according to an embodiment of the invention is schematically shown.

[0057] from Figure 1 As known from the prior art, the contact hook 10 has a fastening section 11 for fastening to the motor or motor parts (such as the rotor, the star disk of the rotor, the stator, etc.), wherein the fastening section 11 provides for the first resistance welding electrode 13 (see Figure 4 ) of the first contact surface 12. The hook section 14 is connected to the fastening section 11, and the hook section provides a second resistance welding electrode 16 (see Figure 4 ) of the second contact surface 15. The hook section 14 is materially connected to the fastening section 11.

[0058] If also from Figure 1 It is known that the hook section 14 is constructed and arranged so that Figure 1 In the first assembled state shown in FIG, the hook section 14 forms together with the fastening section 11 a slot 17 for receiving a wire 18 connected to the winding arrangement, wherein the free end of the hook section 14 forms a slot opening 19 for inserting the wire 18 into the slot 17 in a manner spaced apart from the fastening section 11. Figure 3 In the second assembled state of the contact hook 10 shown in FIG, the free end of the hook section 14 rests against the fastening section 11 such that it closes the groove opening 19. In the second assembled state, the first contact surface 12 and the second contact surface 15 extend in parallel with each other.

[0059] exist Figure 1 In the exemplary embodiment of the contact hook 10 shown in FIG. 1 , the first contact surface 12 and the second contact surface 15 are provided on the same side of the contact hook 10 , here the upper side.

[0060] In addition, Figure 1 It can be seen that the groove 17 extends from the groove opening 19 to the groove bottom 20 in an inclined manner relative to the first contact surface 12 .

[0061] Furthermore, in the contact hook 10 shown here, the groove 17 has a uniform diameter D from the groove opening 19 to the groove bottom 20 in the first assembly state, but is not necessarily limited thereto. At the groove opening 19, the diameter D of the groove 17 may also be larger than the wire diameter and substantially decrease to the wire diameter until the groove bottom 20. In any case, the diameter D of the groove 17 is selected so that it is always slightly larger than the wire diameter of the wire 18 to be inserted, in order to ensure that the wire 18 can easily slide into the groove 17.

[0062] from Figure 1 It can also be seen in the drawing that in the illustrated contact hook 10 , an undercut 21 is provided in the transition region between the fastening section 11 and the hook section 14 , but the invention is not necessarily limited thereto.

[0063] Figure 2 Schematically shows Figure 1 A side view (upper figure) and a top view (lower figure) of a contact hook 10 in FIG. 1 are used to explain a method for manufacturing a contact hook 10 by means of a needle winding technique according to an embodiment of the present invention (for example, in Figure 3 A method of contacting device 30 as shown in FIG.

[0064] After the first assembly state of the contact hook 10 is provided, the wire 18 is inserted into the groove 17 by means of the winding needle 22. To this end, the winding needle 22 moves relative to the contact hook 10. Figure 2 Due to the special design of the contact hook 10, which is open on one side in the first assembly state of the contact hook, and the groove 17, which extends obliquely relative to the first contact surface 12 (which also provides a contact surface for the wire 18), the wire 18 is placed in the groove opening 19 (the wire 18 shown in the dotted line) and is loaded with the wire tension F applied by the winding needle 22. Zug At the slot opening 19, the tension F Zug Generates a force component F parallel to the groove 17 BEW , which moves the wire 18 and allows it to slide through the slot opening 19 to the slot bottom 20. The force component F BEWThe wire 18 is always in the same position in the groove bottom 20, which has a very favorable effect on the subsequent resistance welding process. Another significant advantage of the contact hook 10 is that when the wire 18 is placed at the groove bottom 20, the wire lead-out angle 24 never exceeds 90°. The wire lead-out angle 24 is always less than 90°.

[0065] Another advantage of the contact hook 10 shown is that the windability is improved despite the naturally existing component tolerances and / or movement tolerances of the winding needle. As already mentioned, the wire 18 has a certain bending slack after being led out of the winding needle 22 and is bent to different degrees depending on various factors, such as wire tension, wire diameter, etc. In the contact hook 10 here, the wire 18 can slide along the first contact surface 12 serving as a contact surface beside the slot opening 19. As a result, the wire 18 is pre-positioned on the corresponding contact surface and the bending slack of the wire has no influence during laying. This significantly simplifies the targeted alignment of the slot 17.

[0066] After the wire 18 has been placed on the groove bottom 20, the second assembled state of the contact hook 10 is established by bending the hook section 14 (for example by means of a punch). Figure 3 Right side view), so that the free end of the hook section 14 rests on the fastening section 11, and the first contact surface 12 and the second contact surface 15 extend in a manner parallel to each other.

[0067] Figure 3 Schematically shows Figure 1 A first side view of a contact hook 10 in a first assembled state of a contact device 30 according to one embodiment of the invention (left) and a second side view of the contact hook 10 in its second assembled state (right), the contact device being used to provide an electrical contact with a winding arrangement of an electric machine (neither of which is shown). In the example shown here, the contact hook 10 is fastened to a rotor 40 of the electric machine (see Figure 5 ) at the star disk 31. Figure 3 In FIG. 3 , the star disk 31 is only partially shown, ie only an axial end section of the star disk 31 is shown.

[0068] exist Figure 3 4 shows the axial direction A of the star disk 31 mounted on the rotor 40. The wire 18 connects the contact hook 10 to the winding arrangement in an electrically conductive manner, which is the rotor winding in this case. Figure 3 In the contact device 30 shown in FIG. 1 , a supporting contour 32 is located on the star disk 31 adjacent to the contact hook 10 for supporting the wire 18 .

[0069] In the first assembled state of the contact hook 10 (in Figure 3In the left figure in FIG. 1 , that is, in the unwelded state, the contact hook 10 still protrudes beyond the axial end of the star disk 31 or beyond the support structure 32 in the axial direction A. After the welding process, that is, in the second assembled state of the contact hook 10 (in Figure 3 In the right figure in FIG. 1 , the contact hook 10 is closed and rests on the star disk 30 within the support contour 32 in the axial direction A. In the second assembly position of the contact hook, the contact hook 10 does not protrude beyond the support contour 32. As a result, no axial structural space loss occurs due to the contact hook 10, and the resulting electric machine has an increased power density.

[0070] Figure 4 Schematically shows Figure 3 A side view of the contact device 30 is provided for explaining the resistance welding process. Figure 4 In the embodiment, the first resistance welding electrode 13 has been in contact with the first contact surface 12 of the contact hook 10 (see Figure 1 ) and the second resistance welding electrode 16 has contacted the second contact surface 15 (see Figure 1 Then, the hook section 14 is welded together with the fastening section 12 by means of the first resistance welding electrode 13 and the second resistance welding electrode 16 to establish an electrically conductive connection between the wire 18 and the contact hook 10 .

[0071] The choice of welding electrodes is particularly important in resistance welding, because the welding electrodes have a great influence on the quality of the welding result. Especially in the case of copper welding, this material has only a very low resistance, so most of the temperature comes from the electrodes.

[0072] In the case of the contact hook 10, it should be noted that heat is required only in the region 33 of the wire 18. Therefore, two electrodes 13 and 16 are preferably used which differ in their material properties. In particular, the first electrode 13 is preferably selected to have a low electrical resistance, for example made of a copper material, and the second electrode 16 is preferably selected to have a high electrical resistance, for example made of a tungsten material.

[0073] In this way, a locally limited thermal influence can be achieved, i.e., in the case of the contact hook 10, to which the wire 18 or the welding point is subjected during resistance welding, which ultimately also increases the mechanical stability of the contact hook compared to the prior art. This can be seen in the tensile forces, which are approximately 100 N higher for the contact hook 10. This is particularly important when considering contact under mechanical load, such as, for example, when the rotor is rotating.

[0074] Figure 5 Schematically shows the Figure 33D view of a rotor 40 with a contact device 30 in FIG. A laminated core 42 having six magnetic poles is arranged on a rotor shaft 41. A star disk 31 is arranged at the respective axial end faces of the laminated core 42. The wires (also not shown) of the rotor winding (not shown) are electrically conductively connected to the contact hooks (not shown) respectively mounted on the star disk 31 via the respective star disks 31.

[0075] In addition, the invention disclosed herein enables a simplified winding process associated with wire placement by sliding the wire (tolerance) laterally into the groove of the contact hook; a robust and stable welding quality by secure positioning of the wire at the bottom of the groove; an improved mechanical stability by more targeted, localized heat introduction during resistance welding; and a simple fixation of the wire at the bottom of the groove after winding by bending the hook section (for example with the aid of a die) so as to ensure the desired welding position of the wire at the bottom of the groove in the second assembled state of the contact hook.

[0076] List of reference numerals:

[0077] 10 Contact hook

[0078] 11 Fastening section

[0079] 12 First contact surface

[0080] 13. First resistance welding electrode

[0081] 14 Hook Section

[0082] 15 Second contact surface

[0083] 16 Second resistance welding electrode

[0084] 17 slots

[0085] 18 Wire

[0086] 19 slot opening

[0087] 20 slot bottom

[0088] 21 side concave part

[0089] 22 Winding needle

[0090] 23 Movement Trajectory

[0091] 24 Wire lead angle

[0092] 30 Contact device

[0093] 31 Star Plate

[0094] 32 Support profile

[0095] 33 High fever area

[0096] 40 Rotor

[0097] 41 Rotor shaft

[0098] 42 Laminated Core

[0099] A Axial

[0100] D Diameter

[0101] I Current

[0102] F Zug pull

[0103] F BEW Motion force

Claims

1. A contact hook (10) for providing electrical contact with a winding arrangement of an electric machine, the contact hook comprising: a fastening section (11) for fastening to an electric machine, the fastening section providing a first contact surface (12) for a resistance welding electrode (13); as well as a hook section (14) adjoining the fastening section (11), the hook section providing a second contact surface (15) for a resistance welding electrode (16), The hook section (14) is designed and arranged to form a groove (17) for receiving a wire (18) connected to the winding device together with the fastening section (11) in a first assembly state, wherein the free end of the hook section (14) forms a groove opening (19) for inserting the wire (18) into the groove (17) in a manner spaced apart from the fastening section (11), wherein in a second assembly state, the free end of the hook section (14) abuts against the fastening section (11) in a manner closing the groove opening (19) so that the first contact surface (12) and the second contact surface (15) extend in a manner parallel to each other.

2. The contact hook according to claim 1, characterized in that: A first contact surface (12) and a second contact surface (15) are provided on the same side of the contact hook (10).

3. The contact hook according to claim 1 or 2, characterized in that: The groove (17) extends from a groove opening (19) to a groove bottom (20) in an inclined manner relative to the first contact surface (12).

4. The contact hook according to any one of the preceding claims, characterized in that The first contact surface (12) forms a contact surface for the wire (18) for placing the wire (18) in front of the slot opening (19) in a first assembled state.

5. The contact hook according to any one of the preceding claims, characterized in that In a first assembled state, the groove (17) has a uniform diameter (D).

6. The contact hook according to any one of the preceding claims, characterized in that An undercut (21) is provided in the transition region between the fastening section (11) and the hook section (14).

7. A contact device (30) for providing electrical contact with a winding arrangement of an electric machine, the contact device comprising: - a contact hook (10) according to any one of the preceding claims, and - A wire (18) connecting the contact hook (10) to the winding arrangement.

8. The contact device according to claim 7, characterized in that The winding arrangement is a winding arrangement of a rotor (40) of an electric machine, and the contact hook (10) is mounted on a star disk (31) of the rotor (40).

9. The contact device according to claim 7 or 8, characterized in that A supporting contour (32) for supporting a wire (18) is arranged adjacent to the contact hook (10), wherein the contact hook (10) does not protrude beyond the supporting contour (32) in its second assembly position.

10. A method for producing a contact device (30) according to any one of claims 7 to 9, the method comprising the following steps: - providing the contact hook (10) in a first assembled state, - inserting the wire (18) into the groove (17) of the contact hook (10) with the aid of the winding needle (22), - pulling the wire (18) into the bottom (20) of the groove (17), - establishing a second assembled state of the contact hook (10) by bending the hook section (14) so ​​that the free end of the hook section (14) abuts against the fastening section (11) and the first contact surface (12) and the second contact surface (14) extend in parallel with each other, - bringing the first resistance welding electrode (13) into contact with the first contact surface (12), - bringing the second resistance welding electrode (16) into contact with the second contact surface (15), - resistance welding of the hook section (14) and the fastening section (11) is performed by means of a first resistance welding electrode (13) and a second resistance welding electrode (16) to produce an electrically conductive connection between the wire (18) and the contact hook (10).

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