Star disk with plastic overmold; electric machine; method for manufacturing a star disk

Abstract

The invention relates to a star disk (1) for a rotor of an electric machine, which has arms (2) which are provided for winding with wire of a winding, and with a switching ring (3) from which contacts (4) protrude, wherein the switching ring (3) is held in a rotationally fixed manner in a recess (5) of the star disk (1), wherein the star disk (1) has a plastic injection molding (6) on the outside which fixes the switching ring (3) to the star disk (1) in a form-fitting manner in the axial direction (7). The invention also relates to an electric machine and a method for manufacturing the star disk (1).

Description

[0001] The invention relates to a star disk for a rotor of an electric machine, which has (pole) arms which are provided for winding with wire of a winding or for winding with wire to form a winding, with a switching ring from which contacts, i.e. contacts for contacting the wire of the winding, protrude axially, wherein the switching ring is held in a rotationally fixed manner, for example in a form-fitting and / or material-fitting manner, in a (centering) recess or cutout or centering diameter of the star disk.

[0002] According to a prior art of the applicant, namely DE 10 2022 110 466 A1, a star disk and a method for producing a star disk are already known, in which the star disk is produced by means of a forging process.This document discloses a method for producing a disk-shaped solid formed component, in particular for producing a star disk for an electric motor, wherein in the manufactured state the solid formed component extends along a main extension plane and has at least one substantially radially extending web section with respect to an axis running perpendicular to the main extension plane, comprising: - forging a starting body, wherein the starting body has a primary region which comprises the at least one radially extending web section of the manufactured solid formed component, and a secondary region and removing the secondary region, for example by means of machining and additionally or alternatively by a punching process, in order to expose at least part of the at least one web section, in particular to expose a central region of the at least one web section.

[0003] From DE 10 2021 122 066 A1, a star disk for a rotor of a separately excited synchronous machine is known, in which at least the surface of the star disk is made of plastic, into which busbars for connecting rotor windings are embedded by injection molding, and which each have a contacting element at their two ends for receiving a winding wire that protrudes from the surface of the star disk.

[0004] DE 10 2013 004 659 A1 discloses a switching ring for an electrical machine and an electrical machine having such a switching ring. The switching ring has at least one electrically conductive switching ring element that has a plurality of contact points for electrical connection to partial windings of a stator or rotor of the electrical machine, as well as optionally at least one connection point for electrical connection to the outside. The switching ring has an insulating coating comprising a polymer and produced using an electrodeposition process.

[0005] The object of the present invention is to provide a star washer which improves the positioning of the contacts, facilitates a high insulation quality, is less complex to manufacture and provides a particularly high stability.

[0006] This is achieved with a star disk by incorporating a (two-part) plastic overmold on the outside of the star disk, which positively secures, holds, or attaches the switching ring to the star disk in the axial direction. This eliminates the need for a separate or additional attachment of the switching ring to the star disk, as the switching ring is held in place by the plastic overmold (itself, i.e., by it). This also provides numerous manufacturing advantages, as, among other things, separate fastening devices and assembly processes are eliminated.

[0007] Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

[0008] The switching ring can be manufactured by injection molding and have one or more bridges embedded in plastic. The bridge can have one or more contacts. Preferably, the bridge is embedded in a plastic that forms the switching ring. For this purpose, the bridge can be formed with the (integral) contacts, wherein the bridge is largely or extensively covered with plastic, so that only the contacts are free of plastic. This allows the switching ring to be electrically insulated except for the contacts, so that function is not impaired. Particularly preferably, the contact can be a winding contact or a slip ring contact. The contact can be a "crimp fork" or a solder contact.

[0009] A bridge can be understood as a component that serves as a busbar. Such busbars are usually made of a highly electrically conductive material, such as aluminum or copper.

[0010] It is advantageous, for example, if the star disk has a star disk base body that forms, has or geometrically predetermines the star-shaped, protruding arms. These arms of the star disk base body can preferably have head sections extending in the circumferential direction on both sides at the free ends. The arms and the head sections can preferably be designed in an anchor-shaped cross-section. Due to the high rotation speeds of the star disk expected during operation, forces, in particular centrifugal forces, act on the star disk. It is therefore advantageous to use steel as the material for the star disk, since a star disk base body made of steel, in particular a forged star disk base body, can easily compensate for the forces occurring during operation.

[0011] It is expedient if the plastic overmolding has a section that engages over the switching ring as a cover, ring, ring section or tab. The switching ring is preferably radially outward, i.e. on an outer side in the axial direction and additionally or alternatively engages over the radial direction. In the case of a cover, the plastic overmolding can rest in a wall-like manner in the axial direction on the circumference of the switching ring and overlap the surface of the switching ring in the axial direction. This provides a design and additionally or alternatively embedding of the switching ring in the plastic overmolding, which covers the switching ring in the axial direction along the circumferential direction on its front side. In the case of a ring, the switching ring can rest in a wall-like manner in the axial direction on the circumference of the switching ring. This enables a design and additionally or alternatively embedding of the switching ring in the plastic overmolding, which covers the switching ring along the circumference on the outside.

[0012] In addition, the switching ring can have a geometry with, on the one hand, depressions and raised portions extending in the axial direction and, on the other hand, projections or bulges and recesses or indentations extending in the radial direction such that predetermined sections of the switching ring are completely, predominantly, partially or partially covered with parts of the plastic overmolding. The depressions and raised portions offer the advantage of the switching ring that material not required for the purpose of the switching ring can be omitted, thereby saving weight. The raised portions enable a simplified arrangement of the switching ring in an overmolding tool. The raised portions preferably form a centering geometry that supports the relative arrangement. The projections have the advantage that alignment of the switching ring on the star disk is simplified.The projections can be spaced apart from one another by 180° in the circumferential direction. The recesses can be arcuate or semicircular, preferably extending from the radial outside to the radial inside. The projections can have an underside, with which the projections abut against a surface of the star disk base body in the axial direction. Preferably, a raised portion is formed on at least some of the projections, which is covered by the plastic overmolding in the axial direction. This makes the switching ring particularly stable and allows it to be held particularly stably.

[0013] Furthermore, on the outside of the switching ring, a positive connection can be made with the plastic overmolding, either in addition to the positive connection or alternatively with the positive connection. The switching ring is held to the star disk by means of this positive connection. Various contours or shapes are possible for a positive connection, which can be implemented, for example, using the recesses described above and, in addition to or alternatively, with additional, separate shapes.

[0014] It is advantageous if the switching ring is radially centered on an outer side, preferably a front outer side or end face, in a receptacle of the star disk base body. The receptacle is preferably in the form of a stepped shoulder or a step in the axial direction or in the form of a groove. In addition to centering, this facilitates the positioning of the switching ring on the star disk. Furthermore, the design of the receptacle makes it easier to cover the switching ring with the plastic overmolding, since the receptacle can form a space in which the plastic overmolding can accumulate and thus adhere to the switching ring.

[0015] In addition, the switching ring can have a branch channel or preferably three branch channels distributed over the circumference. The branch channels are preferably arranged at equal distances from one another in the circumferential direction. The branch channels can be arranged in the circumferential direction at the positions of the, preferably arc-shaped, recesses. The individual branch channels can extend at least partially in the radial direction, preferably from radially outside to radially inside, in the switching ring. Part of the plastic overmolding can be arranged in the branch channels, whereby the switching ring is held to the star disk. The branch channel is provided for secure positioning of the bridges during production of the switching ring (by means of a plastic overmolding).Furthermore, the branch channels are preferably filled, completely filled, or completely closed during the formation of the plastic overmolding, so that the switching ring is held or fixed to the star disk by the plastic overmolding. In other words, the branch channel serves not only to enclose or ensure the durability of the plastic overmolding, but also to securely position the bridges during the overmolding process for producing the switching ring.

[0016] It is also advantageous if the star disk base body is designed with a hole for receiving an anti-twist projection on the switching ring. In other words, a poka-yoke solution can be provided to secure the position of the switching ring before overmolding and for assembly in the steel star disk. The anti-twist projection preferably projects axially in a different direction than the contact. Thus, the switching ring can have the contacts on the front side, a side facing away from the star disk base body, and the anti-twist projection on the rear side, a side facing the star disk base body. The anti-twist projection can have a star-shaped contour or a circular, rectangular, or polygonal cross-section. A pin-like design is conceivable.

[0017] The switching ring can preferably have one or more anti-twist projections. The or each anti-twist projection enables the switching ring to be positioned on the star disk base body without undesired circumferential displacement. This allows the switching ring to be held in the correct position for the manufacturing process during the star disk production using the plastic overmolding.

[0018] It is expedient if laminations, preferably a laminated core formed from a plurality of individual laminations stacked in the longitudinal direction, are positioned between two star disks arranged at a distance from one another in the axial direction. The two star disks, which are arranged at a distance from one another in the axial direction, are preferably designed differently. For example, a first star disk is designed with a switching ring according to the embodiments described above, while a second star disk is designed with a plastic ring without contacts. The two star disks, together with the laminated core arranged between the star disks, can form a rotor. In this design, the winding wire is preferably wound around the two star disks in the longitudinal direction.

[0019] The invention also relates to an electric machine with a rotor comprising a star disk as described above and a stator that interacts with the rotor during operation. Such electric machines can be operated as motors or generators. The principle of the star disk design is theoretically also transferable to a stator design.

[0020] The invention also relates to a method for producing a star disk, preferably as described above, wherein in a first step a star disk base body is created for the star disk: Then a switching ring with axially projecting contacts (but with its contact-free front side) is applied to the star disk base body (directly or indirectly, i.e. with the interposition of one or more components). A distance and a minimum thickness of insulation are maintained between the steel star disk and the electrically conductive contacts in order to reduce or eliminate the risk of arcing or short circuits. Then a plastic overmolding is applied (directly or indirectly, i.e. with the interposition of one or more components) over the surface of the star disk base body and at least part of the switching ring such that the switching ring is fixed to the star disk base body in the axial direction.This process simplifies the production of the star disk because a separate production step in which the switching ring is attached to the star disk can be omitted.

[0021] The switching ring can be manufactured in a preliminary step by injection molding using one or more bridges as inserts. In other words, one or more bridges can be overmolded with plastic to form the switching ring. The contacts, preferably made of copper, are coated or stamped with silver solder to efficiently establish electrical contact with a connecting component.

[0022] The position and / or orientation of the star disk base body and the switching ring are determined by an (overmolding) tool.

[0023] The star disk base body can be preheated.

[0024] It is advisable if the star disk base body is first cast and then machined (by cutting) or milled or turned from solid material.

[0025] It is advantageous if the switching ring is partially filled with a branch channel filling. The branch channel filling is preferably carried out radially inward. The branch channel filling allows the switching ring to be secured to the star disk base body. This ensures circumferential rotation and axial retention.

[0026] In other words, the invention relates to a star disk made of steel, which is machined from a formed part, machined from solid, or cast. The star disk has a plastic overmolding in a two-part design, with a switching ring or switching ring with copper contacts or contacts and a subsequent or separate overmolding. The copper contacts can be designed with embossed silver solder, whereby these copper contacts are overmolding with plastic as a separate component forming the switching ring, preferably separately from the star disk. For production, the copper contacts are positioned in an overmolding tool. The finished overmolding switching ring has a flat bearing surface, an outer diameter, and a pin or an anti-twist projection for aligning and securing the switching ring in the star disk (for the overmolding process).In the final overmolding process, the switching ring is positioned on the star disk and positively connected to the star disk with plastic.

[0027] In other words, the invention relates to the following method: The bridges can be pre-molded and / or pre-assembled together with the switching ring with precise positioning. They can form the "switching ring" assembly. This assembly can have at least one defined centering geometry that engages in the overmolding tool of the star disk in order to be able to reproduce the reproduced positional accuracy. The star disk base body can be preheated and can be centered by the overmolding tool. By centering the star disk base body and the switching ring in the overmolding tool, the relative positions of the star disk base body and the switching ring can also be produced with precise positioning.

[0028] The switching ring can also be called a contact switching ring. The bridges can also be called contact bridges. The star disc base body can also be called a steel insert or star disc.

[0029] Various advantageous embodiments of the invention are explained in more detail below with reference to a drawing with figures.

[0030] They show: Fig. 1 an exploded view of a star disk according to the invention, Fig. 2 a longitudinal sectional view of a star disk according to the invention in the manufactured state, Fig. 3 the star disc in a perspective front view with plastic overmolding, Fig. 4 the star disc in a perspective front view without plastic overmolding, Fig. 5 the star disc in a perspective rear view without plastic overmolding, Fig. 6 a switching ring in a perspective front view, Fig. 7 the switching ring in a perspective rear view, and Fig. 8 a perspective view of various bridges.

[0031] The figures are merely schematic in nature and serve exclusively to understand the invention. The same elements are provided with the same reference numerals. Features of the individual embodiments can be interchanged and used alternatively or cumulatively.

[0032] The Fig. 1 shows a star disk 1 according to the invention for a rotor of an electric machine (not shown in detail), wherein the star disk 1 has arms 2 which are provided for winding with wire of a winding, with a switching ring 3 from which contacts 4, i.e. contacts for contacting the wire of the winding, protrude axially, wherein the switching ring 3 is held in a rotationally fixed manner in a recess 5 or centering recess or centering diameter of the star disk 1. It should be emphasized that the star disk 1 has a plastic overmolding 6 on the outside, which fixes or retains or fastens the switching ring 3 in the axial direction 7 in a form-fitting manner to the star disk 1.

[0033] The Fig. 1 shows an exploded view of the star disk according to the invention in a schematic view.

[0034] For better clarity, a radial direction 8 and a circumferential direction 9 are defined in addition to an axial direction 7. The axial direction 7 extends in the direction of a central axis 10 of the star disk 1. The radial direction 8 is oriented perpendicular to the axial direction 7. The circumferential direction 9 describes the direction of rotation of the rotor in which the star disk 1 is arranged.

[0035] The star disk 1 has a star disk base body 11 on one side. The star disk base body 11, in turn, has an annular base body 12, which has pole arms 2 distributed in the circumferential direction 9 and arranged evenly relative to one another and projecting outward in the radial direction 8. In the present illustration, a total of six pole arms 2 are shown, whereby a pole arm 2 follows every 60° in the circumferential direction 9.

[0036] Each pole arm 2 has a head section 13, which is plate-shaped and extends in the radial direction 8 on the pole arms 2. The head section 13 and the pole arms 2 have an anchor-shaped cross-section. The annular base body 12 has a recess 5 on the axial front side in the form of an annular step or notch extending in the axial direction 7, in which the switching ring 3 is positioned.

[0037] The switching ring 3, arranged at the front of the star disk base body 11, has a base body 15 made of plastic, which is provided by a plastic overmold, from which contacts 4 protrude in the axial direction 7. The contacts 4 are formed on a bridge 47, whereby three embodiments are shown in the Fig. 8a, Fig. 8b and Fig. 8c are shown in a perspective view.

[0038] On the front side of the switching ring 3, a total of six contacts 4 are arranged at equal spacing from one another in the circumferential direction 9. The contacts 4 can be formed in a block shape. They are shown purely schematically, and other designs are conceivable. The contacts 4 are made of a material separate from the plastic.

[0039] The plastic overmolding 6 is arranged at the front of the switching ring 3 in the axial direction 7. The plastic overmolding 6 has a design similar to the star disk base body 11. The plastic overmolding 6 has an annular base body 17, which has pole arms 18 distributed in the circumferential direction 9 and arranged evenly relative to one another and extending outward in the radial direction 8. In the present illustration, a total of six pole arms 18 are shown, whereby a pole arm 18 is arranged every 60° in the circumferential direction. Each pole arm 18 has a head section 19, which is plate-shaped in the radial direction 8 and attached to the pole arms 18. The head section 19 and the pole arms 18 have an anchor-shaped cross-section. There are, of course, just as many pole arms 2 as there are pole arms 18.

[0040] The plastic overmolding 3 is prepared to be at least partially pressed with its rear side against a surface 20 of the front side of the switching ring 3 (see Fig. 4) and a surface 21 of the front side of the star disk base body 11.

[0041] In Fig. 2 is a sectional view of the star disk 1 according to the invention according to Fig. 1 in the assembled state. Here, the switching ring 3 is positioned in the recess 5. The switching ring 3 has an annular counter-step 22 on the axial rear side that matches the step forming the recess 5. This counter-step 22 is formed radially further outward on the switching ring 3 and penetrates a circumferential outer side 23 of the switching ring 3. The counter-step 22 is designed in the form of a chamfer or step. The switching ring 3 thus has two planes 24, 25.

[0042] A first plane 24 of the switching ring 3 refers to the part of the switching ring 3 that is positioned in the recess 5. A second plane 25 of the switching ring 3 describes how the switching ring 3 rests against the frontal surface 21 of the star disk base body 11.

[0043] The plastic overmolding 6 rests on the switching ring 3 and the star disk base body 11. The plastic overmolding 6 is designed such that it rests on the free outer side 23 of the switching ring 3, which is not covered by an inner side 26 of the recess 5 of the star disk base body 11. The annular base body 17 of the plastic overmolding 6 rests radially inward with its inner side or inner wall or inner circumferential surface 27 at least partially on the free outer wall or outer circumferential surface or outer side 23 of the switching ring 3 and holds the switching ring 3 in a form-fitting manner on the star disk base body 11. The plastic overmolding 6 protrudes beyond the switching ring 3 in the axial direction 7.

[0044] In Fig. 3 shows a concrete design of the star disk 1 with arranged switching ring 3 and plastic overmolding 6.

[0045] The switching ring 3 has recesses 28 and raised portions 29, 30, 31 on its front side, extending in sections in the circumferential direction 9 and formed in the axial direction 7. These recesses 28 and raised portions 29, 30, 31 are formed on the second plane 25 of the switching ring 3. The recesses 28 and raised portions 29, 30, 31 alternate adjacent to one another in the circumferential direction 9.

[0046] In the present embodiment, a total of three recesses 28 and three raised portions 29, 30, 31 are formed. The contacts 4 are arranged in the sections of the raised portions 29, 30, 31.

[0047] In the circumferential direction 9, between a protrusion 29, 30, 31 and a recess 28, a step 32 is formed, which forms a transition from the protrusion 29, 30, 31 to the recess 28 or from the recess 28 to the protrusion 29, 30, 31. Steps 32 directly adjacent to one another in the circumferential direction 9 each form a centering geometry of the switching ring 3 in an overmolding tool, which facilitates the production of the plastic overmolding 6.

[0048] A branch channel 33 is formed in each of the raised portions 29, 30, and 31, extending radially from the outside to the inside. The branch channel 33 has a straight extension in the radial direction 8 and a rectangular cross-section. The branch channel 33 is limited to penetrating the outer side 23, while the branch channel 33 does not penetrate the inner side or inner wall 34 of the switching ring 3. In addition to encasing and ensuring the durability of the plastic overmolding, the branch channel also serves to securely position the bridges during the plastic overmolding process of the switching ring. The inner side 34 of the switching ring 3 has three to six recesses for secure process control during the plastic overmolding process of the switching ring 3.

[0049] On the outer side 23, at the position of the raised portion 29, 30, 31, a radially inwardly extending, arcuate or semicircular first recess or first recess 35 is formed with a radius that is symmetrically aligned to the branch channel 33 in the circumferential direction 9. The recesses 35 penetrate the outer side 23 of the switching ring 3.

[0050] In the recesses 28, a radially inwardly extending arcuate or semicircular second recess or second recess 36 with a radius is also formed. The recesses 36 penetrate the outer side 23 of the switching ring 3.

[0051] The switching ring 3 has two first projections 38 extending in the radial direction 8. The projections 38 are spaced apart from one another by 180° in the circumferential direction 9. The projections 38 are formed partially on a raised portion 29, 30 and partially on a recess 28 in the radial direction 8. A contact 4 is positioned on each portion of the projection 38 of the raised portion 29, 30.

[0052] The design of the plastic overmolding 6 is designed as a cover 39 from the axial direction 7. The second plane 25 of the switching ring 3 is embedded circumferentially by the plastic overmolding 6. The previously described branch channels 33 are filled with the plastic overmolding 6. The recesses 35, 36 are contoured, i.e., not completely filled in the radial direction 8. Circular holes or free spaces 40 are formed in the plastic overmolding 6. This leaves an area free of the plastic overmolding 6. According to the circular shape of the free spaces 40 and their arrangement, the contoured filling of the recesses 35, 36 is formed by the contour of the free spaces 40 in the plastic overmolding 6. The plastic overmolding 6 is designed to be planar to the recesses 28 and elevations 29, 30, 31 on the front.

[0053] The polar arms 2 and the head sections 13 of the star disk base body 11 are covered on the surface side with the plastic overmolding 6.

[0054] In Fig. 4 shows the star disk 1 according to the invention with switching ring 3 without plastic overmolding 6. In this illustration, further projections 41, previously concealed by the plastic overmolding 6, are shown. In addition to the previously described first projections 38 and first and second recesses 35, 36, the switching ring 3 has further recesses 41, 42 and projections 43. Radially outward on the switching ring 3, in the sections of the elevations 29, 30, 31, partial sections with third recesses 41 are formed, which extend partially in the circumferential direction 9. At the same time, a second projection 43 is formed in these partial sections, which extends partially in the circumferential direction 9. Further, fourth recesses 42 are formed on the first projections 38 in the circumferential direction 9 to the adjacent branch channel 33.

[0055] For a single view of the switching ring 3 according to the same perspective, Fig. 6.

[0056] In Fig. 5 is a rear view of the star disk 1 after Fig. 4 shows the star disk base body 11. The star disk base body 11 has a planar rear surface. The star disk base body 11 has a single axial through-hole 44 on the annular base body 12, with an anti-twist projection 45 partially extending into the through-hole 44 in the axial direction 7. The anti-twist projection 45 is formed on the rear side of the switching ring 3. The contour of the anti-twist projection 45 is star-shaped.

[0057] In Fig. 7 shows a rear view of the switching ring 3. In Fig. 7, the switching ring 3 is shown in a perspective rear view. This shows the complete design of the two levels 24, 25 of the switching ring 3. The previously described projections 38, 43 are formed on the second level 25 and extend in the radial direction 8 in sections along the circumferential direction 9. As shown in the Fig. 7, the extension in the radial direction 8 of the first projections 38 is greater than that of the second projections 43. The first projections 38 and second projections 43 have a bottom side 46 which is intended to bear against the surface 21 of the star disk base body 11, i.e. the surface of the annular base body 12. Likewise, in the Fig. Figure 7 shows the previously described anti-twist projection 45. The first plane 24 of the switching ring 3 is annular and constant in the circumferential direction 9. List of reference symbols 1 star disc 2 Polar Arm 3 switching ring 4 Contact 5 Recess 6 Plastic overmolding 7 Axial direction 8 Radial direction 9 Circumferential direction 10 Central axis 11 Star disc base body 12 Base body of the star disk base body 13 Head section 15 Base body of the switching ring 17 Base body of the plastic overmolding 18 Pole arm of the plastic overmolding 19 Head section of the plastic overmolding 20 Surface of the switching ring 21 Surface of the star disk base body 22 Counter-gradation 23 Outside of the switching ring 24 first level of the switching ring 25 second level of the switching ring 26 Inside of the recess of the star disk base body 27 Inside of the plastic overmold 28 first deepening 29 first sublimity 30 second sublimity 31 third sublimity 32 gradations 33 branch canal 34 Inside 35 first jump back 36 second jump 38 first lead 39 lids 40 free space 41 third jump back 42 fourth jump back 43 second lead 44 through hole 45 Anti-twist projection 46 Bottom 47 Bridge QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2022 110 466 A1

[0002] DE 10 2021 122 066 A1

[0003] DE 10 2013 004 659 A1

[0004]

Claims

[1] Star disk (1) for a rotor of an electric machine, wherein the star disk (1) has a plurality of arms (2) which are provided for winding with wire of a winding, with a switching ring (3) from which contacts (4) protrude, wherein the switching ring (3) is held in a rotationally fixed manner in a recess (5) of the star disk (1), wherein the star disk (1) has on the outside a plastic injection molding (6) which holds the switching ring (3) in the axial direction (7) in a form-fitting manner on the star disk (1). [2] Star disc (1) according to claim 1, characterized by that the switching ring (3) is produced by injection molding and has one or more bridges (47) embedded in plastic. [3] Star disk (1) according to claim 1, characterized by that the star disc (1) has a star disc base body (11) which forms the star-shaped protruding arms (2). [4] Star disk (1) according to one of claims 1 to 3, characterized bythat the plastic overmolding (6) has a section which overlaps the switching ring (3) as a cover (39), ring or tab [5] Star disk (1) according to one of claims 1 to 4, characterized by that the switching ring (3) has such a geometry with, on the one hand, depressions (28) and elevations (29, 30, 31) extending in the axial direction (7) and, on the other hand, projections (38, 43) and recesses (35, 36, 41, 42) extending in the radial direction (8), so that predetermined sections of the switching ring (3) are completely or partially covered with parts of the plastic overmolding (6). [6] Star disk (1) according to one of claims 1 to 5, characterized by that on an outer side (23) of the switching ring (3) there is a positive and additional or alternatively material connection with the plastic overmolding (6). [7] Star disk (1) according to one of claims 2 to 6, characterized bythat the switching ring (3) is centered on an outer side (23) in a receptacle of the star disk base body (11). [8] Electric machine with a rotor having a star disk (1) according to one of claims 1 to 7 and a stator cooperating with the rotor during operation. [9] Method for producing a star disk (1), preferably according to one of claims 1 to 7, wherein in a first step a star disk base body (11) is created for the star disk (1), a switching ring (3) with axially projecting contacts (4, 16) is applied to the star disk base body (11) and a plastic overmolding (6) is applied over the surface (21) of the star disk base body (11) and at least a part of the switching ring (3) in such a way that the switching ring (3) is fixed in the axial direction (7) on the star disk base body (11). [10] Method according to claim 9, characterized bythat in a preceding step the switching ring (3) is manufactured by injection moulding. [11] Method according to claim 9 to 10, characterized by that the position and / or orientation of the star disk base body (11) and the switching ring (3) are determined by a tool. [12] Method according to claims 9 to 11, characterized by that the star disk base body (11) is preheated. [13] Method according to claims 9 to 12, characterized by that the switching ring (3) is filled with a puncture channel filling.

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