Current transmission device with segmented ferrite core for separately excited synchronous machine

Abstract

The invention relates to a current transmission device for a separately excited synchronous machine, comprising a stator having a ferrite core, on which at least one coil can be arranged, and a rotor having another ferrite core, on which at least another coil can be arranged, the rotor being connected to the stator in a rotatably mounted manner, at least one of the ferrite cores is composed of a plurality of ferrite segments which can be accommodated in the accommodating base body such that a current can be transferred in a contactless manner between the coil and the other coil by induction.

Description

TECHNICAL FIELD

[0001] The invention relates to a current transmission device for a separately excited synchronous machine, with a segmented ferrite core. The current transmission device supplies current to the coil of the rotor of the separately excited synchronous machine. BACKGROUND

[0002] A general separately excited synchronous machine is known. Such a separately excited synchronous machine has coils in the rotor and in the stator. It is therefore necessary to transmit current into the rotor. For the supply of current to the rotor coil of a separately excited synchronous machine, various solutions are known from the prior art. Here, a contactless current transmission is advantageous, since wear is reduced compared to, for example, a sliding contact.

[0003] Some solutions propose the use of a rotating transmitter as a transformer for supplying the rotor coil. This allows a contactless current transmission by means of induction. The transformer generally consists of two ferrite cores, which are arranged, for example, radially nested, and associated coils, which generate an electric field that is concentrated by the ferrite cores. Here, the two ferrite cores are separated from one another with as small an air gap as possible.

[0004] Such a ferrite core can be manufactured from ferrite powder by means of a sintering process, but this places requirements on the tolerances of the magnetic yoke, which can only be achieved by post-processing for sintered components. SUMMARY

[0005] It is an object of the invention to provide a ferrite core designed by segmentation, so that post-processing is partially eliminated, and for the sections in which post-processing is not eliminated, it is easier to scale up for mass production.

[0006] It is a further object of the invention to propose a technical solution that reduces the manufacturing costs of the ferrite core while maintaining the necessary precision (tolerances).

[0007] This object is achieved by the current transmission device according to claim 1. Furthermore, this object is also achieved by the separately excited synchronous machine according to claim 9 and the apparatus according to claim 10.

[0008] Further preferred design options of the invention result from the dependent claims, the figures and the following description of preferred embodiments of the invention.

[0009] This object is also achieved by the multi-part design of the individual ferrite cores in combination with a specific assembly process.

[0010] According to the application, a current transmission device for a separately excited synchronous machine comprises a stator comprising a ferrite core, a rotor comprising a further ferrite core, wherein at least one coil can be arranged at one ferrite core and at least one further coil can be arranged at the further ferrite core, the rotor is connected to the stator in a rotationally fixed manner and at least one of the ferrite cores is composed of a plurality of ferrite segments which can be accommodated in a receiving base body, so that a current can be transmitted non-contact between one coil and the further coil by induction.

[0011] Ferrite cores are produced by pressing ferrite powder and subsequently sintering the blank. In this process, a considerable shrinkage of the material occurs, which is subject to considerable fluctuations. While this production process is very economical on the one hand, it can only maintain relatively rough geometric tolerances on the other hand.

[0012] This is problematic in the present application, since the transformer core of the current transmission device is designed in two parts, wherein the primary part and the secondary part can be rotated relative to one another. Here, the primary part and the secondary part are the ferrite cores in the stator and the rotor of the current transmission device.

[0013] For low-loss operation, it is desirable for the air gap between the cores to be as narrow as possible. However, contact must not be allowed to occur in any case. Larger geometric tolerances conflict with these requirements.

[0014] Furthermore, relatively narrow tolerances are required in order to be able to precisely guide and mount the cores at their inner or outer diameter by corresponding cooperation with the surrounding parts.

[0015] The tolerances can be reduced from a manufacturing-technical point of view, for example, by a post-machining of the ferrite. However, this significantly increases the production costs. In particular, this grinding or milling process, in which holes (inner walls) are machined, is particularly expensive, since for this small tools are required which have to be operated at high rotational speeds.

[0016] Unlike with a closed annular core, the air gap length can be changed by moving, for example, the inner segments in the case of the individual segments. For two annular cores, while the air gap is reduced at a certain point when the cores are moved radially relative to one another, the air gap is increased at the opposite position to the same extent.

[0017] Thus, by segmentation and movement of the two segments relative to one another, the geometric tolerance of one of the two air gaps can be compensated, ideally to zero.

[0018] In order to reduce the geometric tolerance of the other air gap, it can also be necessary to finish-machine the ferrite.

[0019] It is also possible to have only the outer ferrite core segments designed. This is particularly the case when the inner ferrite core segments are not worth segmenting in terms of cost or effort due to their smaller size or easier processability.

[0020] Here, the coil can be a cylindrical coil. Furthermore, the rotor can be connected to the rotor of a separately excited synchronous machine and serve as a secondary part of the current transmission device to supply the rotor of the separately excited synchronous machine with current in order to operate the separately excited synchronous machine.

[0021] The stator of the current transmission device can be connected to the stator or housing of the separately excited synchronous machine and serve as a primary part of the current transmission device to receive the current required for the operation of the rotor of the separately excited synchronous machine and to transmit it to the secondary part by induction.

[0022] Here, the rotor and the stator of the current transmission device can be connected to one another in a rotationally fixed manner. For example, one of the two sits on a shaft, which is connected to the housing of the other by means of a bearing.

[0023] There are embodiments in which the receiving matrix consists of plastic.

[0024] In order to improve the magnetic properties of the segmented core, the plastic used can contain additives that increase its electrical conductivity.

[0025] There are embodiments in which the receiving matrix is produced by an initial forming process, in particular injection molding, and the ferrite segments are inserted in this initial forming process.

[0026] The receiving matrix can thus be produced in large quantities.

[0027] There are embodiments in which the ferrite segments have recesses which, in the finished state, are at least partially filled by the receiving matrix.

[0028] The injection-molding of the segments, in particular with plastic, can be designed in particular in the region of the contour and form-fit (for example recesses or tenons) so as to ensure that no relative rotation occurs with respect to adjacent structural elements.

[0029] There are embodiments in which at least one coil or a further coil can be contacted via at least one recess which is arranged between two ferrite segments of the respective ferrite core, wherein the coil or the further coil can be arranged at the ferrite core and can be contacted via the recess of the ferrite core.

[0030] Here, a contact channel can be provided which electrically insulates the contact from the ferrite segment or the ferrite core.

[0031] There are embodiments in which at least one coil or the further coil can be contacted through an opening, which is arranged in one of the ferrite sections or in the ferrite core when the ferrite core is not segmented, wherein the one coil or the further coil can be arranged at the ferrite core and can be contacted through the opening of the ferrite core.

[0032] Here, a contact channel can be provided, which electrically insulates the contact from the ferrite sections or the ferrite core.

[0033] There are embodiments in which one ferrite core can be arranged radially inside the further ferrite core or the further ferrite core can be arranged radially inside the one ferrite core, wherein in the arranged state two air gaps are formed between the one ferrite core and the further ferrite core, which are located at the two axial ends of the ferrite cores and are formed between the outer peripheral surface of the ferrite core located radially on the inside and the inner peripheral surface of the ferrite core located radially on the outside, wherein the one coil and the further coil can be arranged in the space between the two air gaps.

[0034] Thereby a transformer with a primary part and a secondary part is provided, wherein the primary part and the secondary part can be rotated relative to each other.

[0035] There are embodiments in which the width of the stator ferrite sections and the rotor ferrite sections is not the same, so that the sum of the opposing ferrite section peripheral surface areas of the one ferrite core and the further ferrite core remains constant at any angle of rotation.

[0036] If the two ferrite cores are uniformly segmented and rotated relative to each other, in some angular positions the sections on the inside and on the outside coincide completely. In other angular positions, a gap between the two sections is opposite to the closed section area of the other core. This causes the induction to fluctuate with the rotor position.

[0037] To prevent this, the width of the sections can not be the same. In particular, the sum of the opposing ferrite section peripheral surface areas of the ferrite core on the inside and on the outside, which form an air gap, remains constant at any angle of rotation.

[0038] According to the invention, the separately excited synchronous machine has a current transmission device according to any of the preceding embodiments.

[0039] According to the invention, the device has a separately excited synchronous machine according to the preceding embodiments.

[0040] The device can be, for example, a passenger vehicle, but can also include, for example, any form of goods transport or personnel transport, such as a goods vehicle, a bus, a transport vehicle, a train, a subway, a tram, a boat and a ship.

[0041] Furthermore, the device can for example comprise a working machine, such as a construction vehicle, a forestry vehicle and an agricultural vehicle, and a construction machine, a forestry machine and an agricultural machine.

[0042] The device can for example be a machine in the field of transport technology or a machine of a production facility.

[0043] Generally, the device can be any machine that can be driven by a rotational movement. BRIEF DESCRIPTION OF DRAWINGS

[0044] Embodiments of the present application will now be described, by way of example only, with reference to the accompanying drawings. In which:

[0045] Figure 1 An embodiment of a ferrite segment for a radially outer ferrite core and a radially inner ferrite core according to the present application is shown;

[0046] Figure 2 An embodiment of a ferrite segment according to the present application is shown, which is arranged in a radially outer ferrite core and a radially inner ferrite core;

[0047] Figure 3 An embodiment of a radially outer ferrite core according to the present application and a radially inner ferrite core according to the present application is shown, which has a receiving base body;

[0048] Figure 4 A cross-section of an embodiment of a radially outer ferrite core and a radially inner ferrite core arranged according to the present application is shown, which has a receiving base body;

[0049] Figure 5 An embodiment of a radially outer ferrite core and a radially inner ferrite core according to the present application is shown, which has a receiving base body;

[0050] Figure 6 An embodiment of a radially outer ferrite core and a radially inner ferrite core according to the present application is shown, which has a receiving base body;

[0051] Figure 7 A cross-section of an embodiment of a ferrite segment according to the present application for a radially outer ferrite core and a radially inner ferrite core is shown, which are arranged in an assembled state relative to each other;

[0052] Figure 8 An embodiment of the arrangement of a ferrite segment according to the present application for the manufacture of a ferrite core is shown;

[0053] Figure 9A current transfer device is shown, which has an outer ferrite core and an inner ferrite core according to the invention;

[0054] Figure 10 A cross section of a separately excited synchronous machine with a current transfer device is shown; and

[0055] Figure 11 A device with a separately excited synchronous machine is shown. DETAILED DESCRIPTION

[0056] Figure 1 An embodiment of a ferrite segment according to the invention is shown, which is used in a radially outer ferrite core and a radially inner ferrite core.

[0057] The ferrite segment 1 for the radially outer ferrite core has a curved segment section 4 and a segment section 3 which is orthogonal to the segment section 4 and is shaped on the inside of the curved portion of the segment section 4.

[0058] The segment section 3 likewise has a curved portion at its radially inner face. The curved portion of the segment section 4 and the curved portion of the segment section 3 are cylindrical and have the same cylinder axis.

[0059] At the segment section 3, a recess 5 is shaped parallel to the orientation of the segment section 4.

[0060] The ferrite segment 2 for the radially inner ferrite core has a curved segment section 6 and a segment section 7 which is orthogonal to the segment section 6 and is shaped on the outside of the curved portion of the segment section 6.

[0061] The segment section 7 likewise has a curved portion at its radially outer face. The curved portion of the segment section 6 and the curved portion of the segment section 7 are cylindrical and have the same cylinder axis.

[0062] At the segment section 7, a recess 8 is shaped parallel to the orientation of the segment section 6.

[0063] Figure 2 An embodiment of a ferrite segment according to the invention is shown, which is arranged in a radially outer ferrite core and a radially inner ferrite core.

[0064] The radially outer ferrite core 10 has six ferrite segments 1. One of the ferrite segments 1 has an opening 13. In arranging the ferrite segments 1, a cavity 12 is formed at the contact face where the recesses 5 are shaped. Figure 1

[0065] The ferrite segments 1 are arranged relative to one another such that the curved segment sections 4, 6 are arranged parallel to one another and the segment sections 3, 7 are arranged parallel to one another. Figure 1 ​4) Forms the outer circumferential surface of the cylinder. Section ( Figure 1 3) Extend into the interior of the cylinder.

[0066] A coil can be accessed through opening 13 or through cavity 12, within the inner region of the ferrite core 10 located radially outward. If cavity 12 is used to access the coil, then the groove ( Figure 1 5) can be molded deeper, thus making the cavity 12 larger. This eliminates the need for molding the opening 13.

[0067] The ferrite core 11 located radially inward has six ferrite segments 2. One of the ferrite segments 2 has an opening 15. When arranging the ferrite segments 2, grooves are formed... Figure 1 A cavity 14 is formed at the contact surface of 8).

[0068] Ferrite segments 2 are arranged relative to each other in a manner that allows for bending of the segment sections ( Figure 1 6) Forms the outer circumferential surface of the cylinder. Section ( Figure 1 7) Extends outward from the cylinder.

[0069] Another coil can be accessed through opening 15 or through cavity 14 in the outer region of the ferrite core 11 located radially inward. If cavity 14 is used to access this other coil, then the groove ( Figure 3 8) can be molded deeper, thus making the cavity 14 larger. This eliminates the need for molding the opening 15.

[0070] The outer ferrite core 10 or the inner ferrite core 11 can be connected to the rotor of the synchronous motor, thereby forming the rotor of the current transmission device. Thus, the rotor of the synchronous motor can have coils through which current flows, and the synchronous motor can be a separately excited synchronous motor.

[0071] The corresponding one of the outer ferrite core 10 and the inner ferrite core 11 thus forms the stator of the current transmission device.

[0072] Figure 2 Embodiments of a radially outer ferrite core according to the invention and a radially inner ferrite core according to the invention are shown, each having a receiving substrate.

[0073] The figure shows an inner ferrite core 10 and an outer ferrite core 11, which are composed of ferrite segments 1 and 2 and housing substrates 22 and 25. The housing substrates 22 and 15 are made of plastic.

[0074] For the radially outer ferrite core 10, four ferrite segments 1 are shown. These ferrite segments 1 are accommodated in an accommodating base body 22 and are thus fixed. Additionally, a further accommodating base body 20 is shown on the inside of the radially outer ferrite core 10. In this further accommodating base body 20, a coil can be accommodated.

[0075] The accommodating base body 22 wraps the ferrite segments 1 at the cover face and the peripheral face. A part of the accommodating base body 22 also extends into the cavity 12. Thus, the ferrite segments 1 are accommodated in the accommodating base body 22 and are fixed by the accommodating base body 22. Figure 2

[0076] The accommodating base body 20 also has a contact channel 21 which extends through openings 13 in the ferrite segments (not shown) to the cover face of the radially outer ferrite core 10. Thus, a contact portion of a coil can be led out to the cover face by means of the contact channel 21 and, thus, the coil can be contacted from the outside (in the state in which the radially inner ferrite core 11 is rotatably supported in the radially outer ferrite core 10). The cover face is formed by segment sections 3 of the ferrite segments 1. Figure 1 Figure 2

[0077] For the radially inner ferrite core 11, four ferrite segments 2 are shown. These ferrite segments 2 are accommodated in an accommodating base body 25 and are thus fixed. Additionally, a further accommodating base body 23 is shown on the peripheral face of the radially inner ferrite core 11. In this further accommodating base body 23, a further coil can be accommodated.

[0078] The accommodating base body 25 wraps the ferrite segments 2 at the inner peripheral face and at the cover face. A part of the accommodating base body 25 also extends into the cavity 14. Thus, the ferrite segments 2 are accommodated in the accommodating base body 25 and are fixed by the accommodating base body 25. Figure 2

[0079] The accommodating base body 23 also has a contact channel 24 which extends through openings 15 in the ferrite segments (not shown) to the cover face of the radially inner ferrite core 11. Thus, a contact portion of a coil can be led out to the cover face by means of the contact channel 24 and, thus, the coil can be contacted from the outside (in the state in which the radially inner ferrite core 11 is rotatably supported in the radially outer ferrite core 10). The cover face is formed by segment sections 3 of the ferrite segments 1. Figure 1 Figure 4

[0080] ​​​​​​In this embodiment, the plastic formed containment bodies 20 and 23 hold the ferrite segments 1 and 2 together in shape connection, these containment bodies at the same time serving as a support or housing for the coils of the current transmission device. The coil support has lugs (tabs) for this, which project into the recess between the ferrite segments 1 or 2. In this design, the plastic bodies can in principle be manufactured separately and then assembled with the components, but this brings disadvantages in terms of tolerances. It is also possible to position the ferrite segments and, if necessary, also the windings in an injection-moulding tool and bond them into one unit by injection overmoulding. The injection-moulded plastic thus simultaneously serves as mechanical holding of the ferrite segments and the coils and as electrical insulation.

[0081] The containment bodies 20, 22, 24 and 25 can be made of plastic, for example by means of an initial shaping process, such as injection moulding. In this case, the ferrite segments 1 and 2 can be placed into the containment bodies 22 and 25 or placed into an injection-moulding tool, where they are oriented and injection overmoulded.

[0082] Furthermore, a coil and another coil can be placed into the containment bodies 20 and 23 or placed into an injection-moulding tool, where they are oriented and injection overmoulded.

[0083] Figure 1 A cross-section of an embodiment of a radially outer ferrite core and a radially inner ferrite core arranged according to the application is shown, with containment bodies.

[0084] The inner ferrite core 10 and the outer ferrite core 11 are shown in the figure, which are composed of the ferrite segments 1 and 2 and the containment bodies 22 and 25. The containment bodies 22 and 15 are made of plastic in this case.

[0085] The radially inner ferrite core 11 is shown in the figure in a state in which it is mounted rotatably inside the radially outer ferrite core 10. The rotatable bearing is not shown here.

[0086] The radially outer ferrite core 10 is accommodated and fixed in the containment body 22. The containment body 22 is joined to the recess of the ferrite segment of the ferrite core 10 with a tab 22a.

[0087] The containment body 20 accommodates the coil 20b and is likewise joined to the recess of the ferrite segment of the ferrite core with a tab 20a. The coil 20b (and the containment body 20) is thus arranged at the radially outer ferrite core, more precisely inside.

[0088] The radially inner ferrite core 11 is accommodated and fixed in an accommodating base 25. The accommodating base 25 is joined with a connecting tab 25a into a recess of the ferrite section of the ferrite core 11.

[0089] The accommodating base 23 accommodates the coil 23b and is likewise joined with a connecting tab 23a into a recess of the ferrite section of the ferrite core. Thereby, the coil 23b (and the accommodating base 23) is arranged at the radially inner ferrite core 11, more precisely outside.

[0090] When the inner ferrite core 11 is rotatably mounted inside the outer ferrite core 10, two air gaps 50a and 50b are formed between the inner ferrite core 10 and the outer ferrite core 11.

[0091] The air gap 50a is formed between a section segment (3) of the ferrite section (1) and a section segment (6) of the ferrite section (2). Figure 1 Figure 1 The air gap 50b is formed between a section segment (7) of the ferrite section (2) and a section segment (4) of the ferrite section (1). Figure 1 Figure 1 The air gap 50b is formed between a section segment (7) of the ferrite section (2) and a section segment (4) of the ferrite section (1).

[0092] The coils 20b and 23b are arranged in the space between the ferrite cores 10 and 11 and the air gaps 50a and 50b. Figure 1 Figure 1 Figure 5 An embodiment of a radially outer ferrite core and a radially inner ferrite core according to the application is shown, which has an accommodating base. Figure 3 In the figure, the inner ferrite core 10 and the outer ferrite core 11 are shown, which are composed of ferrite sections and accommodating bases. The accommodating bases are made of plastic.

[0093] In contrast to

[0094] , the interior of the ferrite cores 10 and 11 cannot be seen, since all ferrite sections and accommodating bases are shown. Figure 6 In the figure, the inner ferrite core 10 and the outer ferrite core 11 are shown, which are composed of ferrite sections and accommodating bases. The accommodating bases are made of plastic.

[0095] In contrast to

[0096] , the interior of the ferrite cores 10 and 11 cannot be seen, since all ferrite sections and accommodating bases are shown. Figure 7 In the figure, the inner ferrite core 10 and the outer ferrite core 11 are shown, which are composed of ferrite sections and accommodating bases. The accommodating bases are made of plastic.

[0097] In the figure, the inner ferrite core 10 and the outer ferrite core 11 are shown, which are composed of ferrite sections and accommodating bases. The accommodating bases are made of plastic.

[0098] ​​​It is also possible to have only the radially outer ferrite core segments designed in sections. This is particularly the case when the radially inner ferrite core segments are not worth sectioning in terms of cost and effort due to their smaller size and easier processing.

[0099] Figure 1 Embodiments of a radially outer ferrite core and a radially inner ferrite core according to the application are shown, which have a receiving base.

[0100] Modified versions of the receiving base are shown in the figures. Components that are not different from the previously described ones are not described again in order to avoid repetition.

[0101] The receiving base 40, which surrounds and holds the ferrite segments by means of a cover surface, and the receiving base 42, which receives the coil, are manufactured in one piece in this embodiment and are connected by a connecting piece 41. The contact channel 47 allows the coil in the receiving base 42 to be contacted. The receiving base 40, the connecting piece 41, the contact channel 47 and the receiving base 42 can be manufactured, for example, by injection-moulding of the ferrite core in an injection-moulding tool.

[0102] The receiving base 45, which surrounds and holds the ferrite segments by means of a cover surface, and the receiving base 43, which receives the coil, are manufactured in one piece in this embodiment and are connected by a connecting piece 44. The contact channel 48 allows the coil in the receiving base 43 to be contacted. The receiving base 45, the connecting piece 44, the contact channel 48 and the receiving base 43 can be manufactured, for example, by injection-moulding of the ferrite core in an injection-moulding tool.

[0103] In this embodiment, the receiving base 40 and 45, which holds the ferrite segments, also takes on further tasks. The plastic injection-moulded part 45 at the (radially outer) secondary-side ferrite core forms a circuit board carrier, which is suitable for receiving a circuit board with contact elements for connecting the secondary-side coil to adjacent electrical components and for electrically insulating it from the environment.

[0104] Since the receiving base 40 and 45 surrounds the ferrite segments from both axial sides, the ferrite segments are also held form-fittingly. At the (radially inner) primary-side ferrite core, the plastic base likewise surrounds the segments from both sides and, in addition to forming a coil support, also forms a plate, which can be used as a resilient, tolerance-compensating stop for the ferrite core unit relative to adjacent components.

[0105] Advantageously, the contact channels 47 and 48, which pass through the coil end of the ferrite, are already provided when the ferrite segments are injection-moulded. Here, the contact channels 47 and 48 can be located within the ferrite segments or can also be located in the region (groove) between the two ferrite segments.

[0106] It is also possible to have only the outer ferrite core sectioned. This is especially the case when the inner ferrite core is not worth sectioning in terms of costs due to its smaller size and easier processing.

[0107] Figure 1 A cross-section of an embodiment of a ferrite section according to the application for a ferrite core located radially outside and a ferrite core located radially inside is shown, which are arranged in an assembled state relative to one another.

[0108] The inner ferrite core and the outer ferrite core are shown in the figure, which are composed of the ferrite sections and the receiving bases 40 and 45. The receiving bases 40 and 45 are made of plastic.

[0109] Only the cross-section of the ferrite core located radially outside and the ferrite core located radially inside is shown in the figure, i.e. the cross-section of the ferrite core on the primary side and the ferrite core on the secondary side. Both are bodies of rotational symmetry.

[0110] The dimensions of the peripheral surfaces 2c and 1c are mainly relevant to the cooperation with surrounding components (not shown). The interaction of the dimensions of the peripheral surfaces 1a and 2a and the peripheral surfaces 1b and 2b determines the length (or dimension) of the two air gaps 50a and 50b between the ferrite cores having the ferrite sections 1 and 2.

[0111] Unlike in the case of a closed toroidal core, in the case of the individual sections, for the inner ferrite core section and the outer ferrite core section, the air gap length can be changed by moving, for example, the inner section. In the case of two toroidal cores, when the cores are moved radially relative to one another, although the air gap is made smaller somewhere, the air gap at the opposite location is made larger to the same extent.

[0112] Thus, by sectioning and the movement of the two sections relative to one another, the geometric tolerances of one of the two air gaps can be compensated, ideally to zero.

[0113] The ferrite section 1 is a ferrite section of a ferrite core located radially outside. Thus, the face 1c is the outer peripheral surface of a cylindrical ferrite core. The ferrite section 1 has two faces 1a and 1b located on the inside of the curved portion of the ferrite section 1 (see the curved portion in Figure 1 ).

[0114] The face 1a is a curved face at the inner end of the section segment (3) and the face 1b is a curved face of the section segment (4), which is located on the inside in the assembled state of the ferrite core (10). Figure 2 Figure 2 Figure 2

[0115] ​​​Furthermore, ferrite segment 2 is the ferrite segment of the ferrite core located radially inward. In the ferrite core ( Figure 4 In the assembled state of 11), surface 2c is located on the inner side. In the ferrite core ( Figure 3 In the assembly state of 11), surfaces 2a and 2b are located on the outside.

[0116] If the ferrite core ( Figure 4 10 and 11) are now assembled relative to each other in a rotatably supported state, so that surfaces 1a and 2a are opposite each other and an air gap 50a is formed between these surfaces. In addition, surfaces 1b and 2b are opposite each other and an air gap 50b is formed between them.

[0117] Arrow 51 indicates the radial movement of ferrite section 2 relative to ferrite section 1. This reduces the air gaps 50a and 50b, thereby improving the current transmission capability of the current transmission device.

[0118] The manufacturing tolerances of the sintered ferrite cores are relevant here. These ferrite cores are formed, compacted, and joined together by pressure and heat. After manufacturing, deformation, shrinkage, or defects (Verzeihen) may occur in the sintered ferrite cores.

[0119] Therefore, the air gap width between the two integral ferrite cores can only be controlled through extensive post-processing, such as turning, milling, or grinding the corresponding opposing surfaces 1a and 2a, as well as surfaces 1b and 2b. This increases the workload, especially on the inner surface of the hollow cylinder.

[0120] The segmented ferrite cores housed in the housing matrix can be positioned relative to each other through the housing matrix. This partially compensates for the shrinkage and distortion of the pumpkin seed shape.

[0121] In order to design two air gaps 50a and 50b with the same thickness and constant thickness over the entire stretch, when using at least one segmented ferrite core, only one of the opposite faces 1a and 2a and faces 1b and 2b needs to be machined (e.g., by turning, milling or grinding).

[0122] Due to the radial movement 51 of the ferrite segment 2 through the accommodating matrix ( Figure 7 or Figure 3 The forming of section 25) is achieved, so now only post-processing of the dimensions of sections 3 and 7 is required, for example, by turning, milling, or grinding. This can be achieved, for example, by post-processing at surfaces 1a and 2b. Generally, post-processing of the outer surfaces requires less work and is easier to scale up to industrial production batches.

[0123] For the radially outer ferrite segments, the decisive dimension is the distance between the two circumferential surfaces 1a and 1b, which is relevant for the formation of the air gap. In this case it is advantageous to post-process the surface 1a of the component, since the tool can more easily access this surface. The unprocessed blank should be left with a corresponding machining allowance. By finishing the surface 1a to set a narrow-tolerance distance between the circumferential surfaces 1a and 1b, the distance between the circumferential surfaces 1a and 1c is also changed. This will be compensated for in the subsequent assembly by the receiving matrix.

[0124] Similar measures also apply to the inner ferrite core segments.

[0125] Instead of the mobile ferrite segment 2 shown in Figure 8 , the ferrite segment 1 can also be moved relative to the ferrite segment 2 by means of the receiving matrix (22 in Figure 7 ).

[0126] In general, it is only necessary for one of the ferrite cores to be segmented in order to design the air gap to have the same, constant thickness within the extension as described above. This makes it possible to minimize the distance of the ferrite cores and thus the thickness of the air gaps 50a and 50b without risking contact of the ferrite cores during the rotational operation of the current transmission device.

[0127] Figure 6 An embodiment of the arrangement of the ferrite segments according to the application is shown for the manufacture of a ferrite core.

[0128] The principle of assembling the individual outer ferrite segments 1 to an outer ferrite core is shown in the figure. The ferrite segments 1 are oriented here along the target inner diameter 60. This can be achieved in such a way that the ferrite segments are pressed from the outside against a cylindrical mold insert, for example a core rod (not shown), which has the target inner diameter 60, with a defined force 62.

[0129] The ferrite segments 1 are thus arranged at the target inner diameter 60 by means of their surface 1a (see surface 1a in Figure 6 ). The arrow 62 represents the pressing force, which presses the surface 1a of the ferrite segments against the core rod of the injection-molding mold and fixes it there for the injection-molding process.

[0130] The cavity of the injection-molding mold is delimited, for example, by the core rod at the target inner diameter 60 and the wall at the target outer diameter 61. The other boundaries of the cavity can be formed, for example, such that a cover surface (40 or 45 in Figure 8 ) and a receiving matrix for the coil (42 or 43 in Figure 5 ) are produced.

[0131] The actual dimensions of the formed circumferential surface la of the assembled segments thus correspond very precisely to the target inner diameter. Furthermore, the dimensions of the ferrite core 1 are designed such that the outer contour of the assembled core lies within the target outer diameter 61 of the core. In order to keep the ferrite core 1 in place even outside the injection-molding mold, it is injection-encased after the orientation with a receiving matrix, for example made of plastic.

[0132] The injection-molding mold is designed such that the outer diameter of the resulting plastic matrix corresponds to the target outer diameter of the resulting core. With plastic injection molding, narrower tolerances can be achieved than with sintered ferrite cores. If the tolerances are not sufficient, mechanical post-processing of the plastic can be carried out more easily and cost-advantageously than with ferrite.

[0133] Now, if the receiving matrix is formed, for example, by injection molding from plastic, the ferrite core is made from the ferrite segments that are received in the receiving matrix.

[0134] If the target inner diameter 60 and the target outer diameter 61 correspond to the desired dimensions of the ferrite core, no post-processing is necessary after the injection-molding process of the receiving matrix. Only the surface la of the ferrite segments 1 can be post-processed after the sintering of the ferrite segments 1 and before the injection-molding process of the receiving matrix, for example by milling or grinding.

[0135] For example, the surface la can also be post-processed after the injection-molding process of the receiving matrix, although technically more complex, since the inner wall of the hollow cylinder has to be machined. However, the surface lb of the ferrite segments 1 can be used at this point to orient and fix them at a target diameter that is larger than the target inner diameter 60.

[0136] Reference is made to Figure 5 , which describes a feasible manufacturing solution for ferrite cores located radially outside (10) in Figure 9 . This feasible manufacturing solution can similarly be used to manufacture assembled ferrite cores located radially inside (11) in Figure 10 .

[0137] To this end, the ferrite segments 2 can be oriented by the surfaces 2a or 2b at the outer wall of the injection-molding mold, which exhibits the target outer diameter, and then embedded in the injection-molding process of the receiving matrix.

[0138] Figure 11 A current transmission device is shown, which has a ferrite core located outside and a ferrite core located inside according to the invention.

[0139] In the figures, an inductive current transmission device for a separately excited synchronous machine is shown.

[0140] The current transmission device 70 has a radially inner ferrite core 11 formed by a receiving base body and a ferrite section, and also has a coil 23b and a contact channel 24. Furthermore, the current transmission device 70 has a radially outer ferrite core 10 formed by a receiving base body and a ferrite section, and also has a coil 20b (contact channel not shown). Furthermore, the current transmission device 70 comprises a hollow shaft 74 and a shaft portion 75.

[0141] The hollow shaft 74 is connected to the radially outer ferrite core 10. Furthermore, the hollow shaft 74 is connected to a shaft 80, which can be the shaft of a rotor of a synchronous machine.

[0142] The shaft portion 75 is connected to the radially inner ferrite core 11. The shaft portion 75 is also connected to a bearing 73. The bearing 73 is in turn connected to the hollow shaft 74 of the radially outer ferrite core 10. As a result, the radially inner ferrite core 10 and the radially outer ferrite core 11 are supported relative to one another and are thus also connected to one another in a rotationally supported manner. Here, the shaft portion 75 can be part of a stator of a synchronous machine.

[0143] The hollow space 71 can contain electronics and circuitry (i.e. act as a circuit board carrier) which in turn actuates the coils of a rotor connected to or comprising the shaft 80 on the basis of the current transmitted by induction between the coils 23b and 20b.

[0144] ​ A cross section of a separately excited synchronous machine with a current transmission device is shown.

[0145] The separately excited synchronous machine 90 has a stator 91 and a rotor 92. The current transmission device 70 is arranged at the rotor 92 and transmits current at the rotor 92.

[0146] ​ An apparatus with a separately excited synchronous machine is shown.

[0147] The apparatus 100 is designed as a vehicle and has a separately excited synchronous machine 90. The separately excited synchronous machine 90 in turn has a current transmission device (not shown).

[0148] The apparatus 100 is shown here as a passenger vehicle, but can for example also comprise any form of goods transport or personnel transport, for example a goods vehicle, a transport vehicle, a bus, a train, a subway, a tram, a boat and a ship.

[0149] Furthermore, the apparatus 100 can for example comprise a work machine, for example a construction vehicle, a forestry vehicle and an agricultural vehicle, and comprise a construction machine, a forestry machine and an agricultural machine.

[0150] The apparatus 100 can for example be a machine of the transport technology sector or a machine of a production facility.

[0151] Generally, the device 100 can be any machine that can be driven by a rotational movement.

[0152] The illustrated embodiments are to be understood as further explanations of the application. Combinations of embodiments are considered. For the exact scope of the present application, reference is made to the following claims.

[0153] List of reference signs

[0154] 1, 2 ferrite section

[0155] 1a, 1b, 1c, 2a, 2b, 2c face

[0156] 3, 4, 6, 7 section section

[0157] 5, 8 recess

[0158] 10, 11 ferrite core

[0159] 12, 14 cavity

[0160] 13, 15 opening

[0161] 20, 22, 23, 25, 40, 42, 43, 45 housing

[0162] 21, 24 contact channel

[0163] 22a, 22a, 23a, 25a, 41, 44 web

[0164] 20b, 23b coil

[0165] 31, 32 coil contact

[0166] 50a, 50b air gap

[0167] 51, 62 arrow

[0168] 60 target inner diameter

[0169] 61 target outer diameter

[0170] 70 current transmission means

[0171] 71 cavity for electronics

[0172] 72, 80 shaft

[0173] 73 bearing

[0174] 90 separately excited synchronous machine

[0175] 91 stator of the separately excited synchronous machine

[0176] 92 Rotor of a separately excited synchronous machine

[0177] 100 Device.

Claims

1. Current transfer device (70) for a separately excited synchronous machine (90), the current transfer device comprising: a stator comprising one ferrite core (10, 11), a rotor comprising another ferrite core (11, 10), wherein at least one coil (20b, 23b) can be arranged at the one ferrite core (10, 11), at least another coil (23b, 20b) can be arranged at the other ferrite core (11, 10), the rotor is connected to the stator in a rotatably bearing manner, and at least one of the ferrite cores (10, 11) is composed of a plurality of ferrite segments (1, 2) which can be accommodated in an accommodating base body (20, 22, 23, 25, 40, 42, 43, 45) in such a way that a current can be transferred non-contactingly between the one coil (20b, 23b) and the other coil (23b, 20b) by induction.

2. The current transfer device (70) according to claim 1, wherein, The accommodating base body (20, 22, 23, 25, 40, 42, 43, 45) is composed of plastic.

3. The current transfer device (70) according to any one of the preceding claims, wherein, The accommodating base body (20, 22, 23, 25, 40, 42, 43, 45) is produced by an initial forming process, in particular injection molding, and the ferrite segments (1, 2) are embedded in the initial forming process.

4. The current transfer device (70) according to any one of the preceding claims, wherein, The ferrite segments (1, 2) have recesses (5, 8) which are at least partially filled by the accommodating base body (20, 22, 23, 25, 40, 42, 43, 45) in the produced state.

5. The current transfer device (70) according to claim 4, wherein At least the one coil (20b, 23b) or the other coil (23b, 29b) can be contacted through at least one recess (5, 8) which is arranged between two ferrite segments (1, 2) of the respective ferrite core (10, 11), wherein the one coil (20b, 23b) or the other coil (23b, 20b) can be arranged at the ferrite core (10, 11) and can be contacted through the recess (5, 8) of the ferrite core.

6. The current transfer device of any preceding claim, wherein, At least the one coil (20b, 23b) or the other coil (23b, 20b) can be contacted through an opening (13, 15) which is arranged in one of the ferrite segments (1, 2) or, when the ferrite core (10, 11) is not segmented, in the ferrite core (10, 11), wherein the one coil (20b, 23b) or the other coil (23b, 20b) can be arranged at the ferrite core (10, 11) and can be contacted through the opening (13, 15) of the ferrite core.

7. Current transfer device (70) according to any one of the preceding claims, wherein The one ferrite core (10, 11) can be arranged radially inside the other ferrite core (11, 10), or the other ferrite core (11, 10) can be arranged radially inside the one ferrite core (10, 11), wherein in the arrangement state, Two air gaps (50a, 50b) are formed between the one ferrite core (10, 11) and the other ferrite core (11, 10), the air gaps are located at the two axial end portions of the ferrite core (10, 11), and are formed between the outer peripheral surface (2a, 2b) of the ferrite core (10, 11) located radially on the inside and the inner peripheral surface (1a, 1b) of the ferrite core (11, 10) located radially on the outside, wherein The one coil (20b, 23b) and the other coil (23b, 20b) can be arranged in the space between the two air gaps (50a, 50b).

8. The current transfer device (70) according to any one of the preceding claims, wherein, The widths of the stator ferrite segments (1, 2) and the rotor ferrite segments (2, 1) are not the same, so that the sum of the opposite ferrite segment peripheral surface areas (1a, 1b, 2a, 2b) of the one ferrite core (10, 11) and the other ferrite core (11, 10) remains constant at any rotation angle.

9. A separately excited synchronous machine (90) having a current transfer device (70) according to any one of the preceding claims.

10. An apparatus (100) having a separately excited synchronous machine (90) according to claim 9.

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