Rotary transmitter for an inductive energy transmission system with reduced losses and high transmission power
Patent Information
- Application Number
- PCT/EP2026/058184
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-27
- Filing Date
- 2026-03-23
- Publication Date
- 2026-10-01
Smart Images
Figure EP2026058184_01102026_PF_FP_ABST
Abstract
Description
[0001] Paul Vahle GmbH & Co. KG
[0002] Westicker Straße 52
[0003] 59174 Kamen
[0004] Rotary transformer for an inductive power transmission system with reduced losses and high transmission power
[0005] The present invention relates to a rotary transformer for inductive energy and / or data transmission from a first side to a second side and / or vice versa, wherein a first side has a primary-side coil arrangement and a primary-side ferrite core arrangement, and a second side has a secondary-side coil arrangement and a secondary-side ferrite core arrangement, wherein the ferrite core arrangements each have a base and walls arranged perpendicular to the base, which together encompass the winding wires of their associated coil arrangement from three sides, wherein the free end faces of the perpendicularly arranged walls form poles which are arranged opposite the poles of the other ferrite core arrangement, and wherein air gaps are located between the interacting poles of the two ferrite arrangements.
[0006] Contactless energy transfer typically occurs when a primary-side coil unit induces a voltage in a secondary-side coil unit by means of a changing magnetic field. Ferrite arrangements, forming magnetic yokes with poles, serve to focus and guide the magnetic circuits. The frequencies of the typically applied primary current are usually between 15 kHz and 250 kHz. To minimize losses during inductive energy transfer, the air gap between the primary and secondary sides should be as small as possible.
[0007] VA0299WO-Registration text / GE / 23.03.2026 Inductive power transfer typically uses different frequency ranges, depending on the specific application and technical requirements. For high-power switching technology in wireless power transfer, the best results are achieved at a resonant frequency between 20 kHz and 150 kHz.
[0008] It is important to note that the choice of frequency depends on various factors, such as the desired transmission range, power output, and the specific requirements of the application. Higher frequencies often allow for more efficient transmission but can also lead to higher losses.
[0009] Inductive power transformers are used in various industrial applications, including the automotive industry and packaging machines with turning stations. When a device moves along a track, a primary conductor is laid along the track, which is gripped by secondary pickups, typically shaped like IIs or Es.
[0010] If energy is to be transferred from a stationary point to a rotating consumer, rotary transformers are usually used.
[0011] Such rotary joints are, for example, from DE 102013010578 A1 , DE 2409043 A1 , WO2013072373 A1 , EP 0374749 A1 , RU 2007768 C1 ,
[0012] EP 0680060 A1 , DE 2233120 A1 and CZ 277956 B6 are known.
[0013] These rotary transformers are all characterized by having a primary-side and a secondary-side coil with multiple turns, as well as primary-side and secondary-side magnetic yokes, each forming two poles arranged as close together as possible. The magnetic yokes usually have a disc-shaped base from which perpendicular walls extend, their free end faces forming magnetic poles. The primary-side and secondary-side poles have the smallest possible air gap between them, with both air gaps always being of equal size.
[0014] VA0299WO-Registration text / GE / 23.03.2026 Such rotary joints are used, for example, in the automotive industry for car body transport, e.g., for rotating units. They are also frequently used in packaging machines when, for example, slides, movable modules, goods, or packages need to be turned.
[0015] If such rotary transmitters are operated at a frequency of over 100 kHz, for example, the losses and thus also the heating of the rotary transmitter increase significantly.
[0016] The object of the present invention is therefore to provide a rotary transmitter that can also be operated at high frequencies above 100 kHz.
[0017] This problem is solved with a rotary transmitter having the features of claim 1. Further developments of this rotary transmitter according to the invention result from the features of the dependent claims referring back to claim 1.
[0018] The rotary transmitter according to the invention is advantageously characterized by the fact that it departs from the conventional concept of uniformly sized air gaps and instead provides air gaps of different sizes. Alternatively or in combination with this, at least one coil arrangement, advantageously the primary-side coil arrangement, can be configured such that it is located closer to one cylindrical wall of the ferrite arrangement than to the other cylindrical wall. Furthermore, the wall thickness of the cylindrical wall of the ferrite arrangement on which the coil arrangement is located directly or in close proximity can be greater than the wall thickness of the cylindrical wall of the ferrite arrangement from which the coil arrangement is located further away. It is advantageous if the wall thicknesses of the two cylindrical walls of the primary-side and the secondary-side yoke are the same.It is particularly advantageous if the radially inner cylindrical wall is thicker than the radially outer cylindrical wall and the coil assemblies are positioned closer to or directly against the inner cylindrical walls. The axial heights of the inner cylindrical walls can be greater than those of the radially outer cylindrical walls, so that the first air gap between the poles of the inner cylindrical walls is smaller than the second air gap formed between the poles by the end faces of the outer cylindrical walls. This configuration is particularly advantageous because the greater wall thickness of the inner cylindrical wall concentrates the largest proportion of the magnetic flux through it. This advantageously reduces core losses.
[0019] The distance between the radial outside of the coil assembly, at least on the primary side, and the radial inside of the externally arranged cylindrical wall of the yoke should be at least a few millimeters, preferably at least 5mm.
[0020] Additionally, the height of the outer cylindrical wall of the primary-side and / or secondary-side yoke can be smaller than the respective inner cylindrical wall, resulting in a larger second air gap between the poles of the outer cylindrical walls than the first air gap formed between the poles of the inner cylindrical walls.
[0021] The aforementioned measures can each, individually or especially in combination, contribute to a situation where at least the primary-side coil arrangement or winding is less strongly penetrated by the magnetic field, thereby advantageously reducing the eddy current losses in the coil arrangement or winding.
[0022] To reduce eddy current losses in the housing, a gap can be provided between the inner wall of the housing and the magnet yokes.
[0023] The empty spaces in the housing created by the spacing are advantageously filled with a potting compound, which also serves, according to the invention, to hold the coil arrangements or windings and the magnet yokes in position in the housing.
[0024] VA0299WO-Registration text / GE / 23.03.2026The housing can advantageously have cooling fins on its cylindrical outer wall to improve the dissipation of the resulting loss-related heat.
[0025] In a particular embodiment, the rotary transmitter according to the invention can be designed such that the primary side is rotatably arranged relative to the secondary side, with the primary side and the secondary side being held in axial and radial directions relative to each other by externally arranged brackets. The brackets can be made of plastic or a lightweight material, such as an aluminum alloy or another metal.
[0026] In a further embodiment of this previously described rotary transmitter, for example a sliding ring disk, in particular made of plastic, can be arranged between the primary side and the secondary side, which in particular determines the size of the air gaps between the magnet yokes.
[0027] Two different possible embodiments of the rotary transmitter according to the invention are explained in more detail below with reference to drawings.
[0028] They show:
[0029] Figure 1: Perspective view of the first possible embodiment of the rotary transmitter according to the invention;
[0030] Figure 2: Side view of the transmitter according to Figure 1;
[0031] Figure 3: Exploded view of the transformer according to Figure 1;
[0032] Figure 4: Sectional view through the transmitter according to Figure 1;
[0033] Figure 4a: Enlarged section of the cross-section through the transmitter according to Figure 1, but this time with the potting compound V;
[0034] Figure 4b: Enlarged section of the cross-section through the transmitter according to Figure 1 to illustrate the design of the magnet yokes 5, 6
[0035] Figure 5: Illustration showing the assembly of the rotary transmitter;
[0036] VA0299WO-Registration text / GE / 23.03.2026 Figure 6: Perspective view of the underside of the rotary transmitter according to Figure 1;
[0037] Figure 7: Side view of a second possible design - without lower tripod bearing;
[0038] Figure 8: Sectional view through the transmitter according to Figure 7.
[0039] Figure 1 shows a perspective view of a first possible embodiment of the rotary transmitter according to the invention. The rotary transmitter shown in Figure 1 has a primary-side housing 2 and a secondary-side housing 1, which are connected to each other by brackets 10. The brackets 10 are firmly connected to the bottom wall 1c of the housing 1 by means of screws 11. On its upper side, the bottom wall 1c of the secondary-side housing 1 has bores with internal threads 1b, by means of which the rotary transmitter can be attached to a first device (not shown). The bottom wall 1c has a recess through which the connecting leads 4a of the secondary-side coil assembly are led to the outside. A retaining clamp 9 serves to fix the connecting lead 4a.
[0040] The brackets 10 have main bracket walls 10a extending parallel to the axis A of the rotary transmitter, which serve for the radial support of the second primary-side housing 2 and also hold the housings 1, 2 together with the first and second sliding ring discs 7, 8 shown in Figure 2 in the axial direction.
[0041] The two housings 1 , 2 have circumferential cooling fins 1 k, 2k on their cylindrical walls 1z, 2z pointing outwards to dissipate the waste heat.
[0042] The base plate 20 is attached to the primary-side housing 2 via connecting rods. The base plate 20 can be connected to a second device (not shown) by means of the bearing screws 22, which are located in the flexible bearings 21. The devices (not shown) can rotate relative to each other about the axis A, thereby transferring electrical energy from the
[0043] VA0299WO-Registration text / GE / 23.03.2026 a device to the other can be inductively transmitted via the rotary transmitter, which must also be arranged coaxially to axis A for this purpose.
[0044] Figure 2 shows a side view of the transformer according to Figure 1. This figure shows the two radially inwardly projecting walls 10c and 10d, which are integrally formed on the bracket wall 10a. The first wall 10d serves to hold the housings 1, 2 axially relative to each other. A stabilizing ring washer 14, which rests against the underside of wall 10d and is fastened to it by means of screws 15, serves to stabilize the wall. A second sliding ring washer 8 rests against the upper flat side of wall 10d, its upper surface bearing against the underside 2u of the bottom wall 2m of the primary-side housing 2, and can slide along it.
[0045] Connecting rods 24 are pivotally mounted on ball joints on the underside 2u of the bottom wall 2m of the primary-side housing 2. Their other ends are also pivotally mounted on ball joints attached to the base plate 20, with bearing cups. This allows for the compensation of certain additional movements and displacements. The electrical connection cable 3a is routed downwards and through the stabilizing ring disc 14, and can thus be connected to a power supply device (not shown) on the second housing.
[0046] Figure 3 shows an exploded view of the transmitter according to Figures 1 and 2. The mechanical structure is particularly easy to see from this view.
[0047] The base plate 20 together with the connecting rods can be provided optionally. The pins 23, 25 with their ball heads 23b, 25b can be screwed into the base plate 20 or into the underside 2u of the base wall 2m with their first ends, at which there is a thread 23a, 25a. The connecting rods 24 have spherical sockets 24a, 24b at both ends, which can be clipped onto the ball heads 23b, 25b of the pins 23, 25.
[0048] VA0299WO-Registration text / GE / 23.03.2026The two sliding ring discs 7, 8 are located at the top and bottom of the housing 2 and can rotate about their axis A relative to the housing 2.
[0049] As already explained, the brackets 10 have an inwardly projecting, platform-like wall 10c, the upper side of which rests against the underside of the secondary housing 1. Due to their fastening by means of the screws 11 to the upper bottom wall 1c of the secondary housing 2, the brackets 10 remain in position relative to the secondary housing 2. The brackets 10 each have circularly curved inner wall sections 10p and 10r on the inside of their main bracket walls 10a, which serve for the radial support of the primary housing 2. The housing 2 has contact surfaces or sliding surfaces 2p and 2q for this purpose.
[0050] On their underside, the brackets have a recess 10t to accommodate the stabilizing ring disc 14.
[0051] Figure 4 shows a sectional view through the rotary transmitter according to Figure 1. To avoid repetition, reference is made to the illustrations of the individual figures already described and described below. The sectional view shows the two yokes 5, 6 arranged in the housings 1, 2, in which the coil assemblies 3, 4 are located. The coil assemblies 3, 4 are designed such that their inner diameter is only slightly larger than the outer diameter of the internally arranged cylindrical walls 5b, 6b, so that the coil assemblies 3, 4 are thus in almost direct contact with the cylindrical walls 5b, 6b.
[0052] Figure 4a shows a close-up of the section through the transformer according to Figure 1, but this time with the potting compound V filling the cavities 18, 19 and holding the coil assemblies 3, 4 together with the yokes 5, 6 in position within the housings 1, 2. The inner cylindrical walls 5b, 6b of the two yokes 5, 6 have the same wall thickness Di and D2, see Figure 4b. The same applies to the outer cylindrical walls 5c, 6c, whose wall thicknesses D3, D4 are also the same, but are significantly smaller in relation to the wall thicknesses Di, D2, in particular by a factor of 1.5 to 2.5.
[0053] VA0299WO-Registration text / GE / 23.03.2026 The heights Hi and H2 of the two inner cylindrical walls 5b, 6b are designed such that the first air gap L1 between their poles 5p1, 6p1 is significantly smaller than the second air gap L2, which is determined by the distance between the poles 5p2, 6p2 formed by the free ends of the outer cylindrical walls 5c, 6c. The heights Hi and H2 do not necessarily have to be equal. The same applies to the heights H3 and H4.
[0054] Both the two housings 1, 2 and the ferrite arrangements 5, 6 embedded therein are shown with central bores or recesses 1a, 2p, 16 and 17. These can be used to accommodate a central shaft (not shown), which then centers the four parts relative to each other. Furthermore, the two housings 1, 2 can then be held axially relative to each other on the shaft by means of, in particular, an integrally formed, collar-shaped projection, retaining rings, screw-on nuts or other locking devices, so that the brackets 10 shown in the figures can be omitted.
[0055] Of course, it is also possible not to provide these bores or recesses, in which case the brackets 10 for fixing the two housings 1, 2 can only be dispensed with if the described first and second devices, which are to be rotated relative to each other and an inductive energy transfer from one to the other is to take place by means of the rotary transmitter, are sufficiently robust and synchronous so that the fastening of the two housings 1, 2 to these devices is sufficient.
[0056] Figure 5 shows an illustration for the assembly of the rotary transmitter according to the invention. For assembly, two brackets 10 are first attached to the secondary-side housing 1. The primary-side housing 2, together with the two sliding ring discs 7, 8, can then be inserted and positioned from the side where the bracket 10 is not yet attached. The stabilizing ring disc 14 can be screwed onto the lower ends of the already mounted brackets 10 either before or after this. Before the base plate is mounted, the last bracket 10 should be attached to the
[0057] VA0299WO-Registration text / GE / 23.03.2026 The secondary-side housing 1 is screwed on, and the last connecting screw for attaching the stabilizing disc 14 to the last bracket 10 is screwed in. After this has been done, the ball-head pins 25 can be attached to the underside 2u of the primary-side housing 2 or screwed into the provided threaded holes. The ball-head pins 23 can also be attached to the base plate 20. Subsequently, the connecting rods 24 with their joint sockets 24a, 24b are clipped onto the ball-head pins 23, 25, thus connecting the base plate 20 to the rotary transmitter. Using the bearing screws 22, which are located in the flexible bearings 21, the base wall can be connected to the second device (not shown) described above.
[0058] Figure 6 shows a perspective view of the underside of the rotary transmitter according to Figure 1.
[0059] Figures 7 and 8 show a side view and a cross-sectional view of a second possible embodiment, which does without the ball-head pin, connecting rods, and base plate and otherwise corresponds to the rotary joint already described in detail. This rotary joint can be rigidly connected to the second device (not shown) or by means of other flexible connecting elements.
[0060] VA0299WO registration text / GE / 23.03.2026
[0061]
[0062] list
[0063] A axis of rotation of the rotary transmitter
[0064] ABi radial distance between the radial outer surface of the primary-side coil assembly 3 and the inner wall of the wall 6c AB2 radial distance between the radial outer surface of the secondary-side coil assembly 4 and the inner wall of the wall 6c AB3 radial distance between the radial outer surface of the wall 6c and the inner surface of the cylindrical wall 5z
[0065] AB4 radial distance between the radial outside of the wall 5c and the inside of the cylindrical wall 5z
[0066] The radial thickness of the inner cylindrical wall 6b of the secondary-side magnet yoke 6
[0067] D2 radial thickness of the inner cylindrical wall 5b of the primary-side magnet yoke 5
[0068] D3 radial thickness of the outer cylindrical wall 6c of the secondary-side magnet yoke 6
[0069] D4 radial thickness of the outer cylindrical wall 5b of the primary-side magnet yoke 5
[0070] L1 first air gap between the magnetic poles formed by the inner cylindrical walls 5b, 6b
[0071] L2 second air gap between the magnetic poles formed by the outer cylindrical walls 5b, 6b
[0072] V potting compound
[0073] 1 secondary-side housing
[0074] 1a circular window-like recess in the bottom wall 1c, in particular formed by a bore, for the optional accommodation of a bearing shaft for the rotary transmitter
[0075] 1b Threaded bores for fastening the secondary-side housing 1 of a first device which rotates relative to a second, in particular stationary, device
[0076] 1c Bottom wall of the pot-shaped secondary-side housing 1
[0077] 1d Recesses for upper collar-shaped ironing board 10b of the ironing board 10
[0078] VA0299WO-Registration text / GE / 23.03.2026Continuation] of the reference list
[0079] 1e Holes with internal thread for fastening the brackets 10
[0080] 1f window-like opening in the floor wall 1c
[0081] 1 k cooling fins
[0082] 1 n thick-walled cooling fin of the secondary housing 1, which with its one outer flat side forms a contact surface 1s for the collar-shaped wall 10c of the bracket
[0083] 1s Mounting surface for collar-shaped wall 10c of the bracket 10
[0084] 1z cylindrical housing wall of the pot-shaped secondary-side housing 1
[0085] 2 primary-side housing
[0086] 2j mounting surface for second sliding ring disc
[0087] 2k cooling fins
[0088] 2m bottom wall of the pot-shaped primary-side housing
[0089] 2n thick-walled cooling fin, which with its one outer flat side forms a contact surface 2s for the first sliding ring disk 7
[0090] 2p radial outer surface of the cooling fin 2n, which abuts the inner wall area 10p of the bracket 10 for supporting the primary-side housing 2 2r radial outer surface of the bottom wall 2m, which abuts the inner wall area 10r of the bracket 10 for supporting the primary-side housing 2
[0091] 2s Mounting surface for first sliding ring disc 7
[0092] 2t circular window-like recess in the floor wall 2m, in particular formed by a bore, for the optional accommodation of a bearing shaft for the rotary transmitter
[0093] 2u Underside of primary-side housing 2
[0094] 2z cylindrical housing wall of the pot-shaped primary-side housing 2 3 primary-side coil arrangement
[0095] 3a Electrical leads brought out of the primary-side coil arrangement
[0096] 3b inner lead to the primary-side coil assembly
[0097] 4 secondary-side coil arrangement
[0098] VA0299WO-Registration text / GE / 23.03.2026Continuation] of the reference list
[0099] 4a Electrical leads brought out of the secondary-side coil arrangement 4
[0100] 5 yokes, primary-side ferrite core arrangement
[0101] 5a Base of the primary-side magnet yoke 5
[0102] 5b radially inner vertically arranged cylindrical wall forming the inner circumferential pole of the magnet yoke 5
[0103] 5c radially outer vertically arranged cylindrical wall, which forms the inner circumferential pole 5p1 of the magnet yoke 5
[0104] 5p1 inner rotating pole of the magnet yoke 5
[0105] 5p2 outer rotating pole of the magnetic yoke 5
[0106] 6 yokes, secondary-side ferrite core arrangement
[0107] 6a Base of the secondary-side magnet yoke 6
[0108] 6b radially inner vertically arranged cylindrical wall forming the inner circumferential pole of the magnet yoke 6
[0109] 6c radially outer vertically arranged cylindrical wall, which forms the inner circumferential pole of the magnet yoke 6
[0110] 6p1 inner rotating pole of the magnet yoke 6
[0111] 6p2 outer rotating pole of the magnetic yoke 6
[0112] 7 first sliding ring disc
[0113] 7a upper sliding surface of the first sliding ring disc
[0114] 7b lower sliding surface of the first sliding ring disc
[0115] 8 second sliding ring disc
[0116] 8a upper sliding surface of the second sliding ring disc
[0117] 8b lower sliding surface of the second sliding ring disc
[0118] 9 Clamp for guiding and securing the cables 4a
[0119] 9a Mounting screws for the clamp 9
[0120] 10 hangers
[0121] 10a Main wall of the stirrup extending parallel to axis A
[0122] 10b upper collar-shaped angled stirrup wall
[0123] 10c first radially inwardly projecting collar-shaped wall of the bracket 10, which with its two flat sides forms contact surfaces for the secondary-side housing 2 and the first sliding ring disc 7
[0124] VA0299WO-Registration text / GE / 23.03.2026Continuation] of the reference list
[0125] 10d second radially inwardly projecting collar-shaped wall of the bracket 10, which with its two flat sides forms contact surfaces for the primary-side housing 2 and the second sliding ring disc 7 10e contact surface
[0126] 10f Plant area
[0127] 10g bore with internal thread for screw 15
[0128] 10p circular arc-shaped inner wall area of the bracket 10 for supporting the primary-side housing 2
[0129] 10q contact surface of the collar-shaped wall 10c for contact with the first sliding ring disc 7
[0130] 10r arc-shaped inner wall area of the bracket 10 for mounting the primary-side housing 2
[0131] 10 holes for the mounting screws 11
[0132] 10t return to accommodate the stabilizing ring disc 14
[0133] 11 fastening screws for bracket wall 10b
[0134] 14 Stabilizing ring washer
[0135] 15 Screw for fastening the stabilizing ring washer 14 to the collar-shaped wall 10d of the bracket
[0136] 16 holes for through-holes for an optional shaft
[0137] 17. Through-hole for an optional shaft
[0138] 18 Space of the primary-side housing to be filled with potting compound 2 19 Space of the primary-side housing to be filled with potting compound 2 20 Base plate
[0139] 21 flexible bearings for the bearing screws 22, which serve to fasten the base plate 20 to a second device, in particular a stationary device
[0140] 22 bearing screws
[0141] 23 ball-head pins
[0142] 23a External thread
[0143] 23b Ball head
[0144] 24 connecting rods
[0145] 24a, 24b sockets
[0146] VA0299WO-Registration text / GE / 23.03.2026 Continuation of the reference list
[0147] 25 ball-head pins
[0148] 25a External thread
[0149] 25b ball head
[0150] VA0299WO registration text / GE / 23.03.2026
Claims
Patent claims 1. Rotary transformer for inductive energy and / or data transmission from a first side to a second side and / or vice versa, wherein - the first side comprises a primary-side coil arrangement (3) and a primary-side ferrite core arrangement (5) and - which has a second side comprising a secondary-side coil arrangement (4) and a secondary-side ferrite core arrangement (6), - wherein the ferrite core arrangements (5, 6) each have a base (5a; 6a) and cylindrical walls (5b, 5c; 6b, 6c) arranged perpendicular to the base (5a; 6a), which together enclose the winding wires of their associated coil arrangement (3, 4) from three sides, - wherein the free end faces of the vertically arranged walls (5b, 5c; 6b, 6c) form poles (5p1 , 5p2; 6p1 , 6p2) which are arranged opposite the poles (5p1 , 5p2; 6p1 , 6p2) of the other ferrite core arrangement (5, 6), - wherein air gaps (L1, L2) are located between the interacting poles (5p1, 5p2; 6p1, 6p2) of the two ferrite arrangements (5, 6), characterized by that either - the size of the air gaps (L1, L2) differs from each other by at least 10% and / or the wall thickness (Di, D2) of one cylindrical wall (5b; 6b) of at least one magnetic yoke (5, 6) is greater than the wall thickness (D3, D4) of the other cylindrical wall (5c; 6c).
2. Rotary transmitter according to the preamble of claim 1 or according to claim 1, characterized in that at least the winding wires of a coil arrangement (3, 4) are not arranged symmetrically between the vertically arranged cylindrical walls (5b, 5c; 6b, 6c), in particular the coil arrangement (3, 4) is designed and arranged VA0299WO-application text / GE / 23.03.2026 such that it is closer to one cylindrical wall (5b, 6b) of the ferrite arrangement (5, 6) than to the other cylindrical wall (5c, 6c).
3. Rotary transmitter according to claim 1 or 2, characterized in that the coil arrangements (3, 4) are located at the base (5a, 6a) of the yokes (5, 6).
4. Rotary transmitter according to one of claims 1 to 3, characterized in that the vertically arranged or cylindrical walls (5b, 5c; 6b, 6c) of a ferrite arrangement (5, 6) have different wall thicknesses (Di, D2, D3, D4).
5. Rotary transmitter according to one of claims 1 to 4, characterized in that the wall thickness (Di, D2) of the cylindrical wall (5b; 6b) of the ferrite arrangements (5, 6), on which the coil arrangement (3, 4) is arranged directly or in close proximity in the radial direction, is / are greater than the wall thickness (D3, D4) of the cylindrical wall (5c; 6c) of the ferrite arrangement (5, 6), from which the coil arrangement (3, 4) is / are arranged further away in the radial direction.
6. Rotary transmitter according to one of claims 1 to 5, characterized in that the wall thicknesses (Di, D2) of the two internally arranged cylindrical walls (5b; 6b) of the primary-side and the secondary-side yoke (5, 6) are of the same thickness.
7. Rotary transmitter according to one of claims 1 to 6, characterized in that the wall thicknesses (D3, D4) of the two outer cylindrical walls (5c; 6c) of the primary-side and secondary-side yoke (5, 6) are of the same thickness.
8. Rotary transmitter according to one of the preceding claims, characterized in that the radially inner cylindrical wall (5b; 6b) is thicker than the radially outer cylindrical wall (5c; 6c), and that the coil arrangements (3, 4) are located closer to or directly against the inner cylindrical walls (5b; 6b). VA0299WO-Registration text / GE / 23.03.20269. Rotary transmitter according to one of the preceding claims, characterized in that the axial heights (Hi, H2) of the inner cylindrical walls (5b; 6b) are longer than the axial heights (H3, H4) of the radially outer cylindrical walls (5c; 6c), such that the first air gap (L1) between the poles (5p1 ; 6p1) of the inner cylindrical walls (5b; 6b) is smaller than the second air gap (L2) formed between the poles (5p2; 6p2) formed by the end faces of the outer cylindrical walls (5c; 6c).
10. Rotary transmitter according to one of claims 1 to 8, characterized in that the axial heights (Hi, H2) of the inner cylindrical walls (5b; 6b) are shorter than the axial heights (H3, H4) of the radially outer cylindrical walls (5c; 6c), such that the first air gap (L1) between the poles (5p1 ; 6p1) of the inner cylindrical walls (5b; 6b) is larger than the second air gap (L2) formed between the poles (5p2; 6p2) formed by the end faces of the outer cylindrical walls (5c; 6c).
11. Rotary transmitter according to one of the preceding claims, characterized in that the distance (AB1, AB2) between the radial outside of the coil arrangement (3, 4), at least on the primary side, and the radial inside of the externally arranged cylindrical wall (5c; 6c) of the yoke (5, 6) is at least a few millimeters, advantageously at least 5mm.
12. Rotary transmitter according to one of the preceding claims, characterized in that the distance (AB3, AB4) between the radial inner side of the coil arrangement (3, 4), at least on the primary side, and the radial outer side of the internally arranged cylindrical wall (5b; 6b) of the yoke (5, 6) is at least a few millimeters, advantageously at least 5mm.
13. Rotary transmitter according to one of the preceding claims, characterized in that, in order to reduce the eddy current losses in the VA0299WO application text / GE / 23.03.2026 housing halves (1 , 2) a gap (AB3, AB4) is formed between the inner wall of the respective housing half (1 , 2) and the magnetic yoke (5, 6) located in the housing half.
14. Rotary transmitter according to one of the preceding claims, characterized in that the voids (18, 19) of the two housing halves (1 , 2) are filled with a potting compound (V) which in particular also serves to hold the coil arrangements or windings (3, 4) and the magnet yokes (5, 6) in position in the respective housing half (1 , 2).
15. Rotary transmitter according to one of the preceding claims, characterized in that the ferrite arrangements (5, 6) are located in respective housing halves (1, 2), which are in particular made of aluminium or die-cast aluminum.
16. Rotary transmitter according to claim 15, characterized in that the housings (1 , 2) have cooling fins (1 k, 2k).
17. Rotary transformer according to one of the preceding claims, characterized in that the current in the primary-side coil arrangement has a frequency between 15 and 200 kHz, in particular 20, 40 or greater than 100 kHz, most advantageously 140-150 kHz.
18. Rotary transmitter according to one of the preceding claims, characterized in that a central shaft is provided for radial positioning of the housings (1 , 2) and / or ferrite arrangements (5, 6), wherein this shaft extends through central bores or recesses (1a, 22p, 16, 17) of the yokes (5, 6) or housings (1 , 2).
19. Rotary transmitter according to claim 18, characterized in that means for axially fixing the housings (1 , 2) are provided on the shaft or can be attached to the shaft.
20. Rotary transmitter according to one of the preceding claims, characterized in that the primary-side housing (1) is rotatably arranged relative to the secondary-side housing (2), wherein the housings (1, 2) are connected by means of VA0299WO-Registration text / GE / 23.03.2026outside bracket (10) are held in axial and radial direction to each other, wherein the brackets (10) may in particular be made of plastic or a light material, such as plastic, an aluminum alloy or a metal.
21. Rotary transmitter according to one of the preceding claims, characterized in that a sliding ring disk (7), in particular made of plastic, is arranged between the primary-side and the secondary-side housing (1 , 2).
22. Rotary transmitter according to one of claims 20 or 21, characterized in that the brackets (10) with one wall (10b) are fixedly arranged on the first housing (1), and that at least two, advantageously all, brackets (10) have additional radially inwardly extending walls (10d) which at least partially encompass the second housing (2) on its lower side (2u) and thus hold the housings (1, 2) together in the axial direction.
23. Rotary transmitter according to claim 20, characterized in that a second sliding ring disk (8) is located between the wall ( 10d) and the underside (2u) of the housing (2).
24. Rotary transmitter according to claim 22 or 23, characterized in that a stabilizing ring disc (14) is located on the side of the wall (10d) facing away from the second housing (2), which is fastened to the walls (10d) of the brackets (10), in particular by means of screws (15). VA0299WO registration text / GE / 23.03.2026