Contactless energy transmission device, kit of parts for producing contactless energy transmission device, rotor of electric machine, and method for assembling rotor

Abstract

The invention relates to a contactless energy transmission device (1) for a rotor (2) of an electric machine (3), in particular a separately excited synchronous machine in the drive train of a motor vehicle, comprising: a hollow shaft (4) which can be coupled in a torque-transmitting manner to the rotor (2) of the electric machine (3); the invention relates to a contactless energy transmission device (1) comprising a rotor (2) and an induction transformer (5), which has an energizable primary winding (6) and a secondary winding (7), which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor (2), and comprising rectification electronics (11), which are connected to the secondary winding (7), the rectifying electronics (11) are located inside and connected to the hollow shaft (4) for common rotation therewith.

Description

Technical Field

[0001] The invention relates to a contactless energy transmission device for a rotor of an electric machine, in particular a separately excited synchronous machine in a drive train of a motor vehicle, the contactless energy transmission device comprising: a hollow shaft, which can be coupled to the rotor of the electric machine in a torque-transmitting manner; and an inductive transformer, which has an energizable primary winding and a secondary winding, which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor, and the contactless energy transmission device has a rectifying electronic device connected to the secondary winding. The invention also relates to a kit of parts for producing the contactless energy transmission device, a rotor of an electric machine and an electric machine. Background Art

[0002] Electric machines are increasingly used to drive motor vehicles in order to create an alternative to fossil fuel-intensive internal combustion engines. Considerable efforts have been made to improve the suitability of electric drives for everyday use and to be able to provide users with the driving comfort to which they are accustomed.

[0003] A detailed description of an electric drive can be found in an article published by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold in the German automobile magazine ATZ, Vol. 113, May 2011, pages 360 to 365, entitled: Hochintegrativ und Flexibel Elektrische Antriebseinheit für E-Fahrzeuge (Highly integrated and flexible electric drive unit for electric vehicles). The article describes a drive unit for a vehicle axle, which includes an electric motor. Such a drive unit is also referred to as an electric axle or an electrically operable drive train.

[0004] In addition to purely electrically operated drive trains, hybrid drive trains are also known. Such drive trains of hybrid vehicles usually include a combination of an internal combustion engine and an electric motor and enable a purely electric operating mode that simultaneously allows both sufficient range and usability, for example in urban areas, but also in particular when driving off-road. In addition, in certain operating situations, drive can also be provided simultaneously by the internal combustion engine and the electric motor.

[0005] When developing electric machines intended for electric axles or hybrid modules, there is a constant need to increase the power density and efficiency of the electric machines while reducing manufacturing costs, since the cost and weight of the vehicle will depend to a large extent on the battery size. In this context, it is also known to design the electric machine as a separately excited synchronous machine (SESM). In this case, the electrical output for exciting the rotor windings must be transmitted to the rotor of the separately excited synchronous machine. For traction machines, contact transformers are usually used for this purpose. When these windings are energized, a magnetic field is generated, which combines with the magnetic field of the stator and generates torque. The strength of the rotor magnetic field can be adjusted by the strength of the supplied current. In this way, the motor behavior can always be adapted to the respective driving situation in the most efficient way.

[0006] The disadvantage of such contact transformers is that the contact between the fixed and rotating parts generates mechanical and electrical losses. Other disadvantages are the wear caused by the friction between the parts, the resulting contamination caused by wear and the relatively large installation space required.

[0007] As an alternative to such contact transformers, contactless inductive transformers are also known, for example. Inductive transformers are usually rotationally symmetrical transformers consisting of a primary winding and a secondary winding and having an air gap. Usually, inductive transformers also have a core, for example made of ferrite. Such a core can consist of one or more parts.

[0008] For example, all parts of the core can be attached to the fixed machine side of the motor, wherein the secondary side winding rotates inside the core. Alternatively, the core parts can be attached to the rotating part of the machine. In this case, the primary core part and the secondary core part are separated by an air gap. Taking into account all tolerances and operating conditions, the air gap must be large enough to ensure that the core parts do not touch each other. For this reason, the rotary transformer parts are usually combined together or connected to another component for this purpose to provide support that can withstand the rotation speed. Examples of such design variations can be found in DE102017214776 A1 or DE201210201826A1. Summary of the invention

[0009] The object of the present invention is now to provide a contactless energy transmission device for the rotor of an electric machine, in particular a separately excited synchronous machine in the drive train of a motor vehicle, which contactless energy transmission device has a compact design and high operational reliability even when transmitting high electrical powers.

[0010] This object is achieved by a contactless energy transmission device for the rotor of an electric motor, in particular a separately excited synchronous motor in the transmission system of a motor vehicle, the contactless energy transmission device comprising: a hollow shaft which can be connected to the rotor of the electric motor in a torque-transmitting manner; and an induction transformer having a primary winding which can be energized and a secondary winding which is spaced apart from the primary winding and can be conductively connected to the winding of the rotor; and the contactless energy transmission device having a rectifying electronic device connected to the secondary winding, wherein the rectifying electronic device is arranged inside the hollow shaft and connected to the hollow shaft so as to rotate together with it.

[0011] This has the advantage that the contactless energy transmission device can be designed to be particularly compact by utilizing the installation space of the hollow shaft for installing the rectifier electronics.

[0012] Advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technically meaningful manner and can define further embodiments of the invention. In addition, the features indicated in the claims are described and explained in more detail in the description, wherein further preferred embodiments of the invention are shown.

[0013] According to a likewise preferred embodiment of the invention, if the hollow shaft is made of an electrically conductive material, such as steel, the hollow shaft shields the induction transformer from surrounding components and systems, thereby facilitating electromagnetic compatibility (EMC) with surrounding components and systems.

[0014] The hollow shaft can be formed in one piece or in several parts. If the hollow shaft consists of several parts, the hollow shaft parts can only be joined together after the induction transformer has been integrated.

[0015] The induction transformer can be integrated at any axial position inside the hollow shaft. For example, the induction transformer can be integrated in the region of the laminated rotor core or in the region of the rotor winding head.

[0016] According to the invention, it is provided that the secondary winding of the induction transformer is arranged inside the hollow shaft. Very preferably, the secondary winding is completely axially positioned inside the hollow shaft. However, in principle, it is also conceivable that the secondary winding is only axially engaged in certain sections of the hollow shaft.

[0017] First, the individual elements of the claimed subject matter of the present invention are explained in accordance with their relevance or mentioned order in the claims, and then particularly preferred embodiments of the subject matter of the present invention are described.

[0018] The rotor is the rotating (rotating) part of the electric machine. The rotor comprises in particular a rotor shaft. The rotor shaft may be hollow, which on the one hand results in a reduced weight and on the other hand allows a lubricant or coolant to be supplied to the rotor body. Preferably, the hollow shaft of the contactless energy transmission device is a rotor shaft of a rotor of an electric machine, which rotor shaft is at least partially hollow.

[0019] In particular, the electric machine can be designed as a rotary machine. In particular, the rotary machine can be configured as a radial flux machine. A radial flux machine is characterized by the fact that the magnetic field lines in the air gap formed between the rotor and the stator extend in the radial direction. The gap between the rotor and the stator is called an air gap. In a radial flux machine, the air gap is a gap that has a circular cross section and whose radial width corresponds to the distance between the rotor body and the stator body.

[0020] In particular, the electric machine is intended for use in a drive train of a hybrid-drive motor vehicle or a fully-electric-drive motor vehicle. In particular, the electric machine is dimensioned such that a vehicle speed of more than 50 km / h, preferably more than 80 km / h and in particular more than 100 km / h can be achieved. The output of the electric motor is particularly preferably more than 50 kW, preferably more than 80 kW and in particular more than 150 kW. Furthermore, it is preferred that the electric machine provides a speed of more than 8000 rpm, particularly preferably more than 12000 rpm, very particularly preferably more than 1500 rpm.

[0021] For the purposes of this application, a motor vehicle is a land vehicle that moves by machine power and is not constrained by railway tracks. The motor vehicle may for example be selected from the group of: a passenger car, a truck, a scooter, a light motor vehicle, a motorcycle, a bus / coach or a tractor.

[0022] The inductive transformer can be arranged inside the hollow shaft. The hollow shaft can be formed in one piece or in several parts. Basically, it is conceivable that the hollow shaft is completely or only partially penetrated by an opening extending in the longitudinal extension of the hollow shaft. For example, it is also conceivable that the hollow shaft has a blind hole, into which the inductive transformer can then be inserted. The hollow shaft is preferably made of a metallic material, in particular of steel.

[0023] The inductive transformer is configured such that an electrical output of preferably more than 1 kW and particularly preferably more than 2 kW can be transmitted at least temporarily without the transformer being electrically or thermally overloaded. Most preferably, the inductive transformer is configured to transmit an electrical output of between 0.5 kW and 10 kW, preferably between 1 kW and 5 kW, particularly preferably between 2 kW and 4 kW.

[0024] The windings of the transformer are made of an electrically conductive but non-ferromagnetic material, such as copper or aluminum, and are electrically insulated from each other. Preferably, the windings are tangentially aligned around the hollow axis, thereby forming a cylindrical annular winding body having a diameter and a longitudinal extension in the axial direction. Most preferably, the windings are wound around and / or in an iron core made of a ferromagnetic material.

[0025] The winding can be formed from one or more electrical conductors having a circular cross section. It is also conceivable that the cross-sectional shape of the electrical conductors forming the winding is different from a circular shape, in particular a rectangular shape. Particularly preferably, the winding can be formed from insulating copper foils which can be wound around each other in a manner similar to toilet paper rolls.

[0026] According to a further advantageous development of the invention, the number of windings of the primary winding can be greater than the number of windings of the secondary winding. This means that when electrical energy is transferred between the primary winding and the secondary winding, a voltage conversion from a relatively high battery voltage to a lower rotor voltage can be achieved.

[0027] In this case, it is further preferred that the voltage applied to the primary winding is between 40 V and 1500 V, preferably between 100 V and 1000 V, most preferably between 300 V and 850 V. Furthermore, in this case, it is preferred that a voltage between 70 V and 500 V is applied to the secondary winding.

[0028] The primary core and / or the secondary core are made of a ferromagnetic material, preferably a ferrite material. The primary core and / or the secondary core can be designed in several parts. The individual core parts are preferably substantially rotationally symmetrical, but can contain elements and recesses for fixing or passing additional components.

[0029] Particularly preferably, the primary core and / or the secondary core each have an annular spatial form. Most preferably, the primary core and / or the secondary core have a U-shaped cross-sectional profile with circumferential grooves. Preferably, the grooves of the U-shaped cross-sectional profiles of the primary core and the secondary core point towards each other. It is also particularly preferred that the primary winding is located in the slots of the primary core and / or the secondary winding is located in the slots of the secondary core.

[0030] Preferably, the radial outer diameter of the cylindrical annular secondary winding is less than 500 mm, preferably less than 400 mm, particularly preferably less than 350 mm. Most preferably, the radial outer diameter of the cylindrical annular secondary winding is selected to be between 100 mm and 500 mm, preferably between 150 mm and 400 mm, most preferably between 200 mm and 350 mm. This allows the centrifugal forces acting during operation to be limited to an advantageous magnitude.

[0031] The axial length of the cylindrical annular secondary winding is preferably greater than 50%, preferably greater than 70%, of the radial outer diameter, in particular the diameter of the secondary winding. This "elongated" design of the winding has proven to be particularly advantageous for the energy transmission of the induction transformer. In short, the flat and elongated design of the cylindrical annular secondary winding has proven to be particularly advantageous for the energy transmission characteristics of the induction transformer.

[0032] It is further highly preferred that the axial length of the cylindrical annular primary winding is between 80% and 120% of the axial length of the cylindrical annular secondary winding, which may also contribute to a good energy transfer between the windings.

[0033] Furthermore, it is advantageous if the two axial lengths of the cylindrical ring winding completely overlap axially, so that the energy transfer between the primary winding and the secondary winding can be further optimized.

[0034] Furthermore, it can be advantageous if the primary core and the secondary core each form a surface adjacent to the air gap, via which the magnetic flux is guided from one part to the other. It is advantageous if the surface of the primary core adjacent to the air gap completely covers the surface of the secondary core adjacent to the air gap and / or if the surface of the secondary core adjacent to the air gap completely covers the surface of the primary core adjacent to the air gap, wherein the energy transfer between the primary winding and the secondary winding can be further optimized.

[0035] The rectification electronics may preferably be connected between the secondary winding and the winding of the rotor, so that the secondary winding energizes the winding of the rotor via the interconnected rectification electronics.

[0036] The primary winding may be mounted rotatably relative to the secondary winding and centered relative to the secondary winding, preferably by means of one or more rolling bearings. For this purpose, the rolling elements are arranged to roll between an inner ring and an outer ring of the rolling bearing.

[0037] The inner ring can be made of a metallic material and / or a ceramic material. In principle, it is conceivable to design the inner ring in one part or in multiple parts, in particular in two parts. The inner ring can have an inner ring groove. In particular, the cover gasket, the sealing gasket and / or the seal can be arranged in the inner ring groove in a force-fitting and / or form-fitting manner. The inner ring groove is preferably formed as a circumferential groove in the inner ring.

[0038] The outer ring can be made of a metallic material and / or a ceramic material. In principle, it is conceivable to form the outer ring in one part or in multiple parts, in particular in two parts. The outer ring can have an outer ring groove. In particular, the cover gasket, the sealing gasket and / or the seal can be arranged in the outer ring groove in a force-fitting and / or form-fitting manner. The outer ring groove is preferably formed as a circumferential groove in the outer ring.

[0039] Depending on the type of rolling bearing, the rolling elements have the shape of a ball or a cylinder. Roller-shaped rolling elements are also called roller bearing elements, and spherical rolling elements are also called bearing balls. Roller-shaped rolling elements can, for example, be selected from the group consisting of symmetrical spherical rollers, asymmetrical spherical rollers, cylindrical rollers, needle rollers and / or tapered rollers.

[0040] Rolling elements can roll in a rolling bearing, in particular on an inner ring raceway of an inner ring. For this purpose, the surface of the inner ring raceway can advantageously be designed to be correspondingly wear-resistant, for example by means of corresponding surface treatment methods and / or by applying corresponding additional material layers. The inner ring raceway can be designed to be planar or profiled. The profiled design of the inner ring raceway can be used, for example, to guide the rolling elements on the inner ring raceway. On the other hand, the planar form of the inner ring raceway can, for example, allow a certain axial displacement capability of the rolling elements on the inner ring raceway.

[0041] The rolling element can roll in the rolling bearing, in particular on the outer ring raceway of the outer ring. For this purpose, the surface of the outer ring raceway can advantageously be designed to be correspondingly wear-resistant, for example by means of a corresponding surface treatment method and / or by applying a corresponding additional material layer.

[0042] The outer ring raceway can be designed to be flat or contoured. The contoured design of the outer ring raceway can be used, for example, to guide the rolling elements on the outer ring raceway. On the other hand, the flat form of the outer ring raceway can, for example, allow the rolling elements to have a certain axial displacement capability on the outer ring raceway.

[0043] The rolling elements can be guided and spaced apart in a cage or by rolling element spacers. In principle, it is also conceivable to design a rolling bearing without a cage, which is also called a full-complement rolling bearing. In a full-complement rolling bearing, adjacent rolling elements can touch each other.

[0044] The rolling bearing may have a cage, wherein the cage guides the rolling elements. The cage is designed so that the rolling element balls and / or rolling element rollers are spaced apart from one another, so that, for example, friction and heating of the rolling elements are kept as low as possible. Furthermore, the cage keeps the rolling element balls and / or rolling element rollers at a fixed distance from one another during rolling, thereby achieving a uniform load distribution. The cage may be manufactured in one or more pieces.

[0045] Rolling bearings may have seals to prevent lubricant from escaping from the rolling bearing or to prevent dust or moisture from entering the rolling bearing. To this end, the seals used may be provided with one or more sealing lips, which can bear against components of the rolling bearing. These seals are designed on the one hand so that they seal the bearing as long as possible throughout the service life and on the other hand so that the friction level generated by adjacent seals is not too high.

[0046] The invention also comprises a method for assembling a rotor of an electric machine, in particular a separately excited synchronous machine in a drive train of a motor vehicle, comprising the following steps:

[0047] providing an inductive transformer having a primary winding which can be energized and a secondary winding which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor, and

[0048] providing a hollow shaft that can be coupled to the rotor of the electric machine in a torque-transmitting manner, and

[0049] Insert the induction transformer into the hollow shaft.

[0050] Furthermore, according to an equally advantageous embodiment of the invention, it can be provided that the rolling bearing has an inner ring and an outer ring, between which a plurality of rolling elements are accommodated, wherein the inner ring is connected to the hollow shaft for co-rotation, and the outer ring is connected to the lance for co-rotation. This is particularly capable of supporting a modular configuration of the rolling bearing and the hollow shaft. To this end, it is further advantageous that the lance has a first barrel annular section, the primary winding is arranged on the outer side surface of the first barrel annular section, and the lance also has a second barrel annular section coaxially arranged with the first barrel annular section, the outer ring of the rolling bearing is arranged on the inner side surface of the second barrel annular section, wherein the diameter of the first barrel annular section is smaller than the diameter of the second barrel annular section. Furthermore, the present invention can also be further developed so that the rolling bearing, the hollow shaft, the lance and the induction transformer form a modular structural unit.

[0051] Preferably, a method for assembling a rotor of an electric machine, in particular a rotor of a separately excited synchronous machine in a drive train of a motor vehicle, may comprise the following steps:

[0052] Provide rotor shaft;

[0053] Provide non-contact energy transmission device;

[0054] Connect the hollow shaft of the contactless energy transmission device to the rotor shaft;

[0055] Connect the secondary winding to the rotor winding,

[0056] The contactless energy transmission device can have rectifying electronics connected to the secondary winding.

[0057] In a likewise preferred embodiment variant of the invention, it can also be provided that the contactless energy transmission device has rectifying electronics which are also arranged inside the hollow shaft and are connected to the hollow shaft for co-rotation therewith.

[0058] According to a further preferred development of the invention, it can also be provided that the rectifying electronics have a circuit board on which the electronic components are arranged, wherein the circuit board has a substantially disk-shaped or circular disk-shaped or cylindrical ring-shaped contour.

[0059] In principle, it is also conceivable that the circuit board is not completely closed or is composed of several sections. Therefore, it is also preferred that the contour of the circuit board is in the shape of a disk segment, a circular disk segment or a cylindrical ring segment.

[0060] In addition, according to an equally advantageous embodiment of the present invention, it can be provided that the circuit board is connected to the hollow shaft in a material-bonded, force-matched and / or form-fitted manner so as to rotate together. Alternatively, the rectifying electronic device can also be accommodated in a housing, the profile of which is substantially in the shape of a disk, a disk segment or a disk, a disk segment, a cylinder ring or a cylinder ring segment, and the housing is connected to the hollow shaft in a material-bonded, force-matched and / or form-fitted manner so as to rotate together. The housing can provide additional mechanical protection, chemical protection or electromagnetic protection for the rectifying electronic device. The housing can be made of, for example, plastic or metal material. The housing can be designed as a single part or multiple parts.

[0061] The rectifying electronics may also be encapsulated in a non-conductive material.

[0062] Furthermore, the invention can be further developed such that a cooling fluid can flow through the hollow shaft so that during operation of the contactless energy transmission the heat generated by the rectifier electronics can be dissipated by means of the cooling fluid, which is particularly advantageous for low-loss operation of the induction transformer.

[0063] The present invention can also be implemented as a parts kit for producing a contactless energy transmission device, which is used for a rotor of an electric motor, especially a separately excited synchronous motor in a transmission system of a motor vehicle. The parts kit specifically comprises:

[0064] An inductive transformer having a primary winding which can be energized and a secondary winding which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor;

[0065] A hollow shaft which can be coupled to the rotor of the electric machine in a torque-transmitting manner;

[0066] • Rectification electronics which may be connected to the secondary winding which may be positioned inside the hollow shaft and which may be connected to the hollow shaft for common rotation therewith.

[0067] This makes it possible to provide the components required for producing the energy transmission device in a particularly convenient manner. For example, the parts kit can be a packaging unit. In addition, the parts kit can be designed as a combination of separate storage containers for storing individual components of the parts kit or corresponding component groups.

[0068] The invention may also include a method for assembling a rotor of an electric machine, in particular a separately excited synchronous machine in a drive train of a motor vehicle. Such an assembly method then comprises, for example, the following steps:

[0069] providing a hollow shaft that can be coupled to the rotor of the electric machine in a torque-transmitting manner, and

[0070] providing an inductive transformer having a primary winding which can be energized and a secondary winding which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor, and

[0071] Provide rectification electronics that can be connected to the secondary winding,

[0072] inserting the rectifying electronics into the hollow shaft so that the rectifying electronics are connected to the hollow shaft for common rotation,

[0073] · Connect the rectifying electronics to the secondary winding of the induction transformer.

[0074] According to an advantageous embodiment of the invention, it can be provided that the primary winding and the secondary winding of the induction transformer are arranged coaxially with respect to one another in the hollow shaft. This embodiment has the advantage that it enables particularly efficient transmission of electrical energy.

[0075] According to a further preferred further development of the invention, it can also be provided that the primary winding is arranged on a lance extending axially into the interior of the hollow shaft. The lance can in particular be designed as a hollow cylindrical shaft.

[0076] Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the lance has at least one cooling channel through which a cooling fluid can flow. The advantageous effect of this embodiment is based on the fact that it enables particularly good cooling of the primary winding.

[0077] According to another particularly preferred embodiment of the invention, it can be provided that the contactless energy transmission device has a rectifying electronic device, which is also arranged inside the hollow shaft and connected to the hollow shaft so as to rotate together with it. In principle, the rectifying electronic device can be arranged at any position in or on the rotor. However, it is preferred that the rectifying electronic device is also located inside the hollow shaft, because the conditions here are also more favorable for the rectifying electronic device in terms of speed stability and thermal conditions.

[0078] Furthermore, the invention can be further developed such that the lance is mounted opposite the hollow shaft via a rolling bearing in the hollow shaft. This embodiment has the advantage that it allows a particularly tight tolerance, and thus small, annular gap to be formed between the primary coil and the secondary coil.

[0079] The object of the present invention is also achieved by a parts kit for producing a contactless energy transmission device, which is used for the rotor of an electric motor, especially a separately excited synchronous motor in the transmission system of a motor vehicle. The parts kit includes: an induction transformer, which has a primary winding that can be energized and a secondary winding spaced apart from the primary winding, which can be conductively connected to the winding of the rotor; a hollow shaft, which can be connected to the rotor of the electric motor in a torque-transmitting manner, and the secondary winding of the induction transformer is arranged inside the hollow shaft and connected to the hollow shaft so as to rotate together with it; and a lance, which can be axially inserted into the interior of the hollow shaft, and the primary winding of the induction transformer is arranged on the lance.

[0080] The resulting advantage is that the components of the contactless energy transmission device to be assembled can be provided in a particularly convenient manner. For example, the parts kit can be a packaging unit. In addition, the parts kit can be designed as a combination of separate storage containers for storing individual components of the parts kit or corresponding component groups.

[0081] According to a further preferred embodiment of the subject matter of the invention, a rotor of an electric machine, in particular a separately excited synchronous machine in a drive train of a motor vehicle, can be provided, comprising a contactless energy transmission device according to one of claims 1 to 7 .

[0082] Finally, the object of the invention is also achieved by an electric machine, in particular a separately excited synchronous machine in a drive train of a motor vehicle, comprising a rotor according to claim 8 .

[0083] According to another further preferred development of the present invention, it can also be provided that the rectifying electronic device has a circuit board on which electronic components are arranged, wherein the circuit board has a roughly disc-shaped, disc-segment-shaped or disc-shaped, disc-segment-shaped or barrel-ring-shaped, barrel-ring-segment-shaped profile. In addition, according to an equally advantageous embodiment of the present invention, it can be provided that the circuit board is connected to the hollow shaft in a material-bonded, force-fitted and / or form-fitted manner so as to rotate together. According to another particularly preferred embodiment of the present invention, it can be provided that the rectifying electronic device is accommodated in a housing, the profile of which is substantially in the shape of a disc, a disc segment or a disc, a disc segment, a barrel ring or a barrel ring segment, and the housing is connected to the hollow shaft in a material-bonded, force-fitted and / or form-fitted manner so as to rotate together. In addition, the present invention can also be further developed so that a cooling fluid can flow through the hollow shaft, so that when the contactless energy transmission device is in operation, the heat generated by the rectifying electronic device can be dissipated by the cooling fluid.

[0084] The object of the invention is also achieved by a rotor of an electric machine, in particular a separately excited synchronous machine in a drive train of a motor vehicle, comprising a contactless energy transmission device according to one of claims 1 to 6 .

[0085] The object of the invention is also achieved by an electric machine, in particular a separately excited synchronous machine in a drive train of a motor vehicle, which comprises a rotor according to claim 7 .

[0086] Finally, the object of the invention is also achieved by a method for assembling a rotor of an electric machine, in particular a separately excited synchronous machine in a drive train of a motor vehicle, comprising the following steps:

[0087] providing a hollow shaft that can be coupled to the rotor of the electric machine in a torque-transmitting manner, and

[0088] providing an inductive transformer having a primary winding which can be energized and a secondary winding which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor, and

[0089] Provide rectification electronics that can be connected to the secondary winding,

[0090] inserting the rectifying electronics into the hollow shaft so that the rectifying electronics are connected to the hollow shaft for common rotation,

[0091] · Connect the rectifying electronics to the secondary winding of the induction transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] The invention is explained in more detail below with reference to the accompanying drawings without limiting the general concept of the invention.

[0093] In the attached picture:

[0094] Figure 1 An electric machine with contactless energy transmission is shown in a schematic axial section,

[0095] Figure 2 A detailed view of a contactless energy transmission device is shown in axial section,

[0096] Figure 3 A kit of parts for producing a contactless energy transmission device for use in a rotor of an electric motor is shown,

[0097] Figure 4 A motor vehicle having an electric machine is shown in a block diagram,

[0098] Figure 5 An inductive transformer is shown in a perspective partial cross-sectional view,

[0099] Figure 6 A first embodiment of the arrangement of rectifying electronics in a hollow shaft is shown in an axial section.

[0100] Figure 7 A second embodiment of the arrangement of rectifying electronics in a hollow shaft is shown in an axial section.

[0101] Figure 8 A third embodiment of the arrangement of rectifying electronics in a hollow shaft is shown in an axial section.

[0102] Fig. 9 A fourth embodiment of the arrangement of rectifying electronics in a hollow shaft is shown in an axial section.

[0103] Fig.10 A fifth embodiment of the arrangement of rectifying electronics in a hollow shaft is shown in axial section,

[0104] Fig.11 A sixth embodiment of the arrangement of rectifying electronics in a hollow shaft is shown in axial section,

[0105] Fig.12 A detailed view of the contactless energy transmission device inside the rolling bearing is shown in an axial section.

[0106] Fig.13 A kit of parts for producing a contactless energy transmission device for a rotor of an electric machine is shown. DETAILED DESCRIPTION

[0107] Figure 1 A contactless energy transmission device 1 for a rotor 2 of an electric motor 3 is shown. Figure 1In the embodiment shown, the electric machine 3 is configured as a separately excited synchronous machine for a drive train 23 of a motor vehicle 24, such as Figure 4 Also shown by way of example in FIG.

[0108] The rotor 2 is rotatably mounted in a cylindrical ring-shaped stator 22, which has a hollow shaft 4, which is connected in a torque-transmitting manner to the rotor 2 of the electric machine 3. The rotor 2 also includes a laminated rotor stack 18, which is connected to the hollow shaft 4 for common rotation. The hollow shaft 4 thus forms the rotor shaft of the rotor 2.

[0109] An induction transformer 5 is provided for energizing the rotor 2 , and has a primary winding 6 that can be energized and a secondary winding 7 that is spaced apart from the primary winding and is electrically conductively connected to the winding of the rotor 2 .

[0110] As from Figure 1 It can be clearly seen that the secondary winding 7 of the induction transformer 5 is arranged inside the hollow shaft 4 and is connected to the hollow shaft so as to rotate therewith, while the primary winding 6 of the induction transformer 5 is positioned in the hollow shaft in a torsionally rigid manner relative to the hollow shaft 4 so that the secondary winding 7 rotates around the primary winding 6. The primary winding 6 and the secondary winding 7 of the induction transformer 5 are arranged coaxially with each other inside the hollow shaft 4. The primary winding 6 is arranged on a lance 8 extending axially into the interior of the hollow shaft 4.

[0111] from Figure 2 It can be clearly seen that the lance 8 can be designed in the shape of a cylindrical ring and thus has an axially extending cooling channel 10 through which the cooling fluid 9 can flow. This ensures that the heat generated at the primary winding 6 can be effectively dissipated. Figure 2 In the embodiment of the hollow shaft 4 shown, the hollow shaft is designed in two parts and comprises a first hollow cylindrical shaft section 4 a and a second hollow cylindrical shaft section 4 b which are connected to one another for common rotation.

[0112] exist Figure 2 In the embodiment shown, the contactless energy transmission device 1 also has a rectifying electronic device 11, which can also be arranged inside the hollow shaft 4 and connected to the hollow shaft so as to rotate together therewith. In principle, it is also conceivable to provide a seal between the hollow shaft 4 and the lance 8 to protect the induction transformer 5 from the ingress of dust and / or cooling fluid, but this is not shown in the figure.

[0113] The laminated rotor core 18 of the rotor 2 is connected to the radially outer side surface of the hollow shaft 4 so as to rotate together. Thus, the rotor winding head 19 extends from the distal end surface of the laminated rotor core 18 in the axial direction.

[0114] Figure 2It is also shown that the hollow cylindrical lance 8 can be mounted relative to the hollow shaft 4 by means of a rolling bearing 12 arranged in the hollow shaft 4 .

[0115] exist Figure 3 In the figure, a kit of parts 21 for producing a contactless energy transmission device 1 for a rotor 2 of an electric machine 3, in particular a separately excited synchronous machine in the drive train of a motor vehicle, is shown. For example, the kit of parts 21 can be used to convert or equip the electric machine 3 from a contact power supply of the rotor 2 to a contactless power supply and to provide corresponding device components for this purpose.

[0116] The parts kit 21 comprises an induction transformer 5 and a hollow shaft 4, the induction transformer having a primary winding 6 to which power can be supplied, and a secondary winding 7 which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor 2, the hollow shaft being capable of being coupled to the rotor 2 of the electric motor 3 in a torque-transmitting manner. In doing so, the secondary winding 7 of the induction transformer 5 is arranged inside the hollow shaft 4 and connected to the hollow shaft so as to rotate together therewith. The parts kit 21 also comprises a lance 8 which can be axially inserted into the interior of the hollow shaft 4, on which the primary winding 6 of the induction transformer 5 is arranged. This means that, for example, an existing hollow shaft can be replaced and replaced with a hollow shaft of the parts kit 21. Subsequently, the annular lance 8 can thus be inserted into the hollow shaft 4, wherein the primary winding 6 and the secondary winding 7 are then coaxially aligned with each other, as Figure 2 The assembled state of the lance 8 is shown in FIG. The rolling bearing 12 in the parts kit 21 is provided as an option for the lance 8 in the form of a storage cartridge ring.

[0117] Figure 5 A detailed view of an induction transformer 5 is shown. A primary core 13 and a secondary core 14 can be seen, each of which has a ring-shaped spatial form. The primary core 13 and the secondary core 14 each have a U-shaped cross-sectional profile with circumferential grooves, wherein the grooves of the U-shaped cross-sectional profiles of the primary core 13 and the secondary core 14 point towards each other.

[0118] The primary winding 6 is located in the slots of the primary core 13, and the secondary winding 7 is located in the slots of the secondary core 14. The primary core 13 and the secondary core 14 are made of ferromagnetic material, preferably ferrite material.

[0119] exist Figure 5 In the illustrated embodiment, the number of windings of the primary winding 6 is greater than the number of windings of the secondary winding 7 , so that when electrical energy is transferred between the primary winding 6 and the secondary winding 7 , voltage conversion from a relatively high battery voltage to a lower rotor voltage can be simultaneously achieved.

[0120] The two axial lengths of the cylindrical annular windings 6 , 7 overlap axially almost completely, which allows an optimal and preferably loss-free energy transfer between the primary winding 6 and the secondary winding 7 .

[0121] Figures 6 to 11 Various possibilities for arranging the rectifying electronics 11 in the hollow shaft 4 are shown.

[0122] exist Figures 6 to 11 In all embodiments of the present invention, the contactless energy transmission device 1 is connected to the secondary winding 7 via rectifying electronics 11. The rectifying electronics 11 are each arranged inside the hollow shaft 4 and connected to the hollow shaft so as to rotate together therewith.

[0123] like Figures 6 to 11 As shown in FIG. , the secondary winding 7 of the induction transformer 5 is preferably arranged inside the hollow shaft 4 and connected to the hollow shaft so as to rotate therewith, while the primary winding 6 of the induction transformer 5 is positioned in the hollow shaft in a torsionally rigid manner relative to the hollow shaft 4, but for the sake of clarity this is not shown in FIG. Figures 6 to 11 Not shown.

[0124] The rectifying electronics 11 has a printed circuit board 33 on which electronic components 34 are arranged.

[0125] exist Fig.10 In the embodiment of FIG. 4 , the circuit board 33 has a substantially disk-shaped or disk-segment-shaped contour, which extends substantially in the radial direction inside the hollow shaft 4 . Figure 8 A similar configuration is shown, in which, however, the circuit board 33 has a disk-shaped or disk-segment-shaped contour, so that the circuit board 33 can be penetrated and / or flowed through in the axial direction.

[0126] Fig. 9 Another possible arrangement of the circuit board 33 is shown, wherein the circuit board 33 has a cylindrical ring-shaped or cylindrical ring segment-shaped contour and extends substantially in the axial direction inside the hollow shaft 4 .

[0127] Figure 6 , Figure 7 , Fig.11 A further embodiment of the rectifying electronic device 11 is shown, in which the rectifying electronic device 11 is accommodated in a housing 36 which is in turn connected to the hollow shaft 4 in a materially bonded, force-fitting and / or form-fitting manner for co-rotation. Fig.11 In an embodiment variant, the housing 36 has an approximately disk-shaped or disk-segment-shaped contour.

[0128] The housing 36 may also have a disc-shaped or disc-segment-shaped profile, as in Figure 6 Thus, for example, the lance 8 or the cooling fluid 9 can pass through the housing 36. Figure 6 and Fig.11 In the embodiment, the housing extends substantially in the radial direction like a disk. In principle, the housing 36 can also extend in the axial direction, such as Figure 7 In this embodiment, the housing has a cylindrical ring shape or a cylindrical ring segment shape.

[0129] from Figures 6 to 11 It can also be seen that the hollow shaft 4 is designed so that a cooling fluid 9 can flow through it, so that when the contactless energy transmission device 1 is in operation, the heat generated by the rectifying electronics 11 can be dissipated by the cooling fluid 9. For this purpose, the hollow shaft 4 also serves as a cooling channel 10, through which the cooling fluid 9 can be conveyed axially.

[0130] Fig.12 An embodiment of the invention is shown, in which the hollow shaft 4 is mounted rotatably relative to a torsionally rigid connection structure 25 by means of rolling bearings 12. In the embodiment shown, the connection structure 25 is a lance 8. The secondary winding 7 of the induction transformer 5 is here also arranged inside the hollow shaft 4 and connected to the hollow shaft for co-rotation therewith, while the primary winding 6 of the induction transformer 5 is positioned in the hollow shaft in a torsionally rigid manner relative to the hollow shaft 4. In the embodiment shown, the primary winding 6 is arranged on a lance 8 extending axially into the interior of the hollow shaft 4.

[0131] The rolling bearing 12 has an inner ring 26 and an outer ring 27 between which a plurality of rolling elements 28 are accommodated, wherein the inner ring 26 is connected for common rotation with the hollow shaft 4 and the outer ring 27 is connected for common rotation with the lance 8 .

[0132] The lance 8 has a hollow cylindrical first barrel ring section 29, the primary winding 6 is arranged on the outer side surface of the first barrel ring section, and the lance 8 also has a second barrel ring section 30 arranged coaxially with the first barrel ring section 29, and the outer ring 27 of the rolling bearing 12 is arranged on the inner side surface of the second barrel ring section, wherein the diameter of the first barrel ring section 29 is smaller than the diameter of the second barrel ring section 30. The rolling bearing 12, the hollow shaft 4, the lance 8 and the induction transformer 5 form a modular structural unit 31.

[0133] even though Fig.12 Not shown in the figure, the contactless energy transmission device 1 can have rectifying electronics 11 which are also arranged inside the hollow shaft 4 and connected to the hollow shaft so as to rotate together therewith.

[0134] Fig.13Another possible kit of parts 21 for producing a contactless energy transmission device 1 for a rotor 2 of an electric machine 3 is shown. The kit of parts comprises an inductive transformer 5 having a primary winding 6 which can be energized and a secondary winding 7 which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor 2, and a hollow shaft 4 which can be coupled to the rotor 2 of the electric machine 3 in a torque-transmitting manner. Furthermore, the kit of parts 21 has rectifier electronics 11 which can be connected to the secondary winding 7 which can be located inside the hollow shaft 4 and can be connected to the hollow shaft for co-rotation therewith.

[0135] For example, you can use Fig.13 The following method for assembling the rotor 2 of the electric machine 3 is performed using a kit of parts 21 known from the prior art. First, a hollow shaft 4 is provided which can be coupled to the rotor 2 of the electric machine 3 in a torque-transmitting manner, and an inductive transformer 5 is provided, which has an energizable primary winding 6 and a secondary winding 7 which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor 2. Rectification electronics 11 which can be coupled to the secondary winding 7 are also provided.

[0136] The rectifying electronics 11 are then inserted into the hollow shaft 4 so that they are connected for common rotation with the hollow shaft 4. Finally, the rectifying electronics 11 can then be connected to the secondary winding 7 of the inductive transformer 5.

[0137] The present invention is not limited to the embodiments shown in the accompanying drawings. Therefore, the above description should not be regarded as limiting, but rather as illustrative. The attached claims should be understood to mean that the stated features exist in at least one embodiment of the present invention. This does not exclude the existence of other features. Where the claims and the above description define a "first" feature and a "second" feature, such naming is used to distinguish between two features of the same type without defining the order of precedence.

[0138] Reference numerals

[0139] 1Energy transmission device

[0140] 2 rotors

[0141] 3 Motor

[0142] 4Hollow shaft

[0143] 5 Transformer

[0144] 6 Primary Winding

[0145] 7 Secondary Winding

[0146] 8 Spear

[0147] 9 Cooling fluid

[0148] 10 cooling channels

[0149] 11Rectifier Electronic Device

[0150] 12 Rolling bearings

[0151] 13 Primary core

[0152] 14 Secondary core

[0153] 15 Star Hat

[0154] 16 Rotor cover

[0155] 17 Shell structure

[0156] 18 Laminated rotor core

[0157] 19 Rotor winding head

[0158] 20 Rolling bearings

[0159] 21 Parts Kit

[0160] 22 Stator

[0161] 23 Powertrain

[0162] 24 Motor Vehicles

[0163] 25 Connection structure

[0164] 26 Inner Ring

[0165] 27 Outer Ring

[0166] 28 Rolling elements

[0167] 29 cylinder ring section

[0168] 30 cylinder ring section

[0169] 31 units

[0170] 32 Rotor shaft

[0171] 33 Circuit Board

[0172] 34 Electronic components

[0173] 35 Profile

[0174] 36 Housing

Claims

1. A contactless energy transmission device (1) for a rotor (2) of an electric motor (3), the electric motor being in particular a separately excited synchronous motor in a drive train of a motor vehicle, the contactless energy transmission device comprising: a hollow shaft (4) which can be coupled to the rotor (2) of the electric motor (3) in a torque-transmitting manner, and an inductive transformer (5) having a primary winding (6) which can be energized and a secondary winding (7) which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor (2), and Rectification electronics (11), which are connected to the secondary winding (7), It is characterized in that The rectifying electronics (11) are arranged inside the hollow shaft (4) and connected to the hollow shaft so as to rotate together with the hollow shaft.

2. The contactless energy transmission device (1) according to claim 1, It is characterized in that The secondary winding (7) of the induction transformer (5) is arranged inside the hollow shaft (4) and connected to the hollow shaft so as to rotate together with the hollow shaft, while the primary winding (6) of the induction transformer (5) is positioned in the hollow shaft in a torsionally rigid manner relative to the hollow shaft (4).

3. The contactless energy transmission device (1) according to claim 1 or 2, It is characterized in that The rectifying electronic device (11) has a circuit board (33) on which electronic components (34) are arranged, wherein the circuit board (33) has a substantially disk-shaped or circular disk-shaped or cylindrical ring-shaped contour (35).

4. The contactless energy transmission device (1) according to claim 3, It is characterized in that The circuit board (33) is connected to the hollow shaft (4) in a materially bonded, force-fitting and / or form-fitting manner so as to rotate together.

5. The contactless energy transmission device (1) according to one of claims 1 to 3, It is characterized in that The rectifying electronic device (11) is accommodated in a housing (36) having a substantially disk-shaped or disk-shaped or cylindrical ring-shaped contour, and the housing (36) is connected to the hollow shaft (4) in a material-bonded, force-fitting and / or form-fitting manner so as to rotate together.

6. The contactless energy transmission device (1) according to one of the preceding claims, It is characterized in that The hollow shaft (4) is designed to allow a cooling fluid (9) to flow through it, so that when the contactless energy transmission device (1) is in operation, the heat generated by the rectifying electronic device (11) can be dissipated by the cooling fluid (9).

7. A kit of parts for producing a contactless energy transmission device (1) for a rotor (2) of an electric machine (3), in particular a separately excited synchronous machine in a drive train of a motor vehicle, the kit of parts comprising: an inductive transformer (5) having a primary winding (6) which can be energized and a secondary winding (7) which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor (2), a hollow shaft (4) which can be coupled to the rotor (2) of the electric motor (3) in a torque-transmitting manner, • Rectification electronics (11) connectable to the secondary winding (7), the secondary winding being positionable inside the hollow shaft (4) and connectable to the hollow shaft so as to rotate together with the hollow shaft.

8. A rotor (2) of an electric machine (3), in particular a separately excited synchronous machine in a drive train of a motor vehicle, comprising a contactless energy transmission device (1) according to one of claims 1 to 6.

9. An electric machine (3), in particular a separately excited synchronous machine in a drive train of a motor vehicle, comprising a rotor (2) according to claim 8.

10. A method for assembling a rotor (2) of an electric machine (3), in particular a separately excited synchronous machine in a drive train of a motor vehicle, comprising the following steps: providing a hollow shaft (4) which can be coupled to the rotor (2) of the motor (3) in a torque-transmitting manner, and providing an inductive transformer (5) having a primary winding (6) which can be energized and a secondary winding (7) which is spaced apart from the primary winding and can be electrically conductively coupled to the winding of the rotor (2), and providing rectification electronics (11) connectable to the secondary winding (7), inserting the rectifying electronics (11) into the hollow shaft (4) so ​​that the rectifying electronics (11) are connected to the hollow shaft (4) for co-rotation, Connecting the rectifying electronics (11) to the secondary winding (7) of the inductive transformer (5).

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