WO2024061412A1

WO2024061412A1 - Contactless energy transmission device, kit-of-parts for manufacturing a contactless energy transmission device, rotor of an electric machine, electric machine, and method for assembling a rotor

Info

Publication number: WO2024061412A1
Application number: PCT/DE2023/100678
Authority: WO
Inventors: Martin Kunkemoeller; Thomas Hurle; Christian Oehler; Christian Hartmann; Jan Michel WASSERMANN; Richard Bernauer; Kevin KLUMPP
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2022-09-23
Filing date: 2023-09-13
Publication date: 2024-03-28
Also published as: DE102022124447A1

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 inside a drive train of a motor vehicle, said energy transmission device comprising: a hollow shaft (4) which can be coupled to the rotor (2) of the electric machine (3) in a torque-transmitting manner; and an inductive transmitter (5) which has an energisable primary winding (6) and a secondary winding (7) which is spaced apart therefrom and can be electrically conductively coupled to a winding of the rotor (2), and the contactless energy transmission device (1) has rectifier electronics (11) connected to the secondary winding (7), the rectifier electronics (11) being located inside the hollow shaft (4) and being connected thereto for conjoint rotation therewith.

Description

Contactless energy transmission device, kit-of-parts for producing a contactless energy transmission device, rotor of an electrical machine and electrical machine and method for assembling one

rotor

The present invention relates to a contactless energy transmission device for a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising a hollow shaft which can be coupled to the rotor of the electrical machine in a torque-transmitting manner, and an inductive transmitter which has a primary winding which can be energized and a secondary winding which is spaced apart from the primary winding and which can be coupled to a winding of the rotor in an electrically conductive manner, and the contactless energy transmission device has rectifier electronics connected to the secondary winding. The invention further relates to a kit of parts for producing a contactless energy transmission device, a rotor of an electrical machine and an electrical machine.

Electric machines are increasingly being used to drive motor vehicles in order to create alternatives to combustion engines that require fossil fuels. Significant efforts have already been made to improve the suitability of electric drives for everyday use and to offer users the usual driving comfort.

A detailed description of an electric drive can be found in an article in the magazine ATZ 113th year, 05/2011, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold with the title: Highly integrative and flexible electric drive unit for electric Vehicles. This article describes a drive unit for an axle of a vehicle, which includes an electric motor. Such drive units are also referred to as e-axles or electrically operated drive trains.

In addition to purely electrically operated drive trains, hybrid drive trains are also known. Such drive trains of a hybrid vehicle usually comprise a combination of an internal combustion engine and a Electric motor, and enable - for example in urban areas - purely electric operation while at the same time providing sufficient range and availability, especially for cross-country journeys. In addition, in certain operating situations it is possible to drive simultaneously using the internal combustion engine and the electric motor.

When developing the electric machines intended for e-axles or hybrid modules, there is a continuing need to increase their power densities and efficiency while at the same time reducing manufacturing costs, since the cost and weight of the vehicle will be largely determined by the battery size. In this context, it is also known to design the electrical machines as separately excited synchronous machines (FSM). The electrical power to excite the rotor windings must be transferred to the rotor of a separately excited synchronous machine. For traction machines, a contact transmitter is usually used for this purpose. When these windings are energized, a magnetic field is created which, in combination with the magnetic field of the stator, generates a torque. The strength of the rotor field can be adjusted based on the strength of the current supply. This means that the machine behavior can always be adapted to the respective driving situation in a way that optimizes efficiency.

The disadvantages of such a contact-based transformer are mechanical and electrical losses in the contact between stationary and rotating components. Other disadvantages are the wear of the components rubbing against each other and the associated contamination through abrasion, as well as the comparatively large installation space requirement.

As an alternative to such contact-based transmitters, contactless, inductive transmitters are also known, for example. An inductive transformer is usually a rotationally symmetrical transformer with an air gap consisting of a primary and a secondary winding. As a rule, an inductive transformer also has a core made of ferrite, for example. Such a core can be made from one or more parts. For example, all parts of the core can be attached to the stationary machine side of an electrical machine, with the secondary-side winding then rotating within the core. Alternatively, core parts can be attached to the rotating part of the machine. In this case, the primary and secondary core parts are separated by an air gap. This must then be large enough so that the core parts do not touch each other, taking all tolerances and operating conditions into account. For this purpose, the rotating transformer parts are often provided with a bandage or joined to another component in order to support them at a fixed speed. An example of such an embodiment variant can be found in DE 102017 214 776 A1 or in DE201210201826 A1.

The object of the invention is now to provide a contactless energy transmission device for a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, which has a compact structure and a high level of operational reliability even with high electrical power to be transmitted.

This object is achieved by a contactless energy transmission device for a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising a hollow shaft which can be coupled to the rotor of the electrical machine in a torque-transmitting manner, and an inductive transmitter which has a primary winding which can be energized and a has a secondary winding spaced therefrom, which can be electrically conductively coupled to a winding of the rotor, and the contactless energy transmission device has rectifier electronics connected to the secondary winding, the rectifier electronics being arranged within the hollow shaft and connected to it in a rotationally fixed manner.

This has the advantage that the contactless energy transfer device can be made particularly compact by using the installation space of the hollow shaft for the rectifier electronics. 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 technologically meaningful manner and can define further embodiments of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

If the hollow shaft is made of an electrically conductive material, for example steel, according to a likewise preferred embodiment variant of the invention, it shields the inductive transmitter from surrounding components and systems, and thus contributes to electromagnetic compatibility (EMC) towards surrounding components and systems.

The hollow shaft can be designed in one piece or in several parts. If the hollow shaft is made up of several parts, these hollow shaft parts can only be put together after the inductive transformer has been integrated.

The inductive transmitter can be integrated at any axial position within the hollow shaft. For example, in the area of a rotor laminated core of the rotor or in the area of the rotor winding heads.

According to the invention it is provided that the secondary winding of the inductive transformer is arranged within the hollow shaft. It is highly preferred that the secondary coil is positioned axially completely in the hollow shaft. In principle, however, it would also be conceivable for the secondary coil to only engage axially in sections in the hollow shaft.

First, the individual elements of the claimed subject matter of the invention are explained in the order of their relevance or their mention in the claim sentence and particularly preferred embodiments of the subject matter of the invention are described below. A rotor is the rotating (rotating) part of an electrical machine. The rotor includes in particular a rotor shaft. The rotor shaft can be made hollow, which on the one hand results in weight savings and on the other hand allows the supply of lubricant or coolant to the rotor body. Preferably, the hollow shaft of the contactless energy transmission device is a rotor shaft of a rotor of an electrical machine, which is at least partially hollow.

The electrical machine can in particular be designed as a rotary machine. The rotary machine can in particular be configured as a radial flow machine. A radial flux machine is characterized by the fact that the magnetic field lines in the air gap formed between the rotor and stator extend in the radial direction. The gap existing between the rotor and the stator is called the air gap. In a radial flux machine, this is a gap with a circular cross-section and a radial width that corresponds to the distance between the rotor body and the stator body.

The electric machine is intended in particular for use within a drive train of a hybrid or fully electric motor vehicle. In particular, the electric machine is dimensioned such that vehicle speeds greater than 50 km/h, preferably greater than 80 km/h and in particular greater than 100 km/h can be achieved. The electric motor particularly preferably has a power greater than 50 kW, preferably greater than 80 kW and in particular greater than 150 kW. It is further preferred that the electric machine provides speeds greater than 8,000 rpm, particularly preferably greater than 12,000 rpm, most preferably greater than 1500 rpm.

For the purposes of this application, motor vehicles are land vehicles that are moved by mechanical power without being tied to railway tracks. A motor vehicle can, for example, be selected from the group of passenger cars (passenger cars), trucks (lorries), mopeds, light vehicles, motorcycles, motor buses (KOM) or tractors The inductive transformer can be arranged within a hollow shaft. The hollow shaft can be formed in one piece or in several pieces. In principle, it is conceivable that the hollow shaft is completely or only partially penetrated by an opening running in the longitudinal extent of the hollow shaft. For example, it would also be conceivable for the hollow shaft to have a blind hole into which the inductive transformer can then be inserted. The hollow shaft is preferably formed from a metallic material, in particular steel.

The inductive transformer is configured in such a way that electrical powers preferably greater than 1 kW and particularly preferably greater than 2 kW can be transmitted at least in the short term without overloading the transformer electrically or thermally. Most preferably, the inductive transmitter is configured to transmit electrical power between 0.5kW-10kW, preferably between 1kW-5kW, particularly preferably between 2kW-4kW.

The windings of the transformer are made of an electrically conductive but not ferromagnetic material, such as copper or aluminum, and are designed to be electrically insulated from one another. The windings are preferably aligned tangentially circumferentially to the hollow shaft, so that a cylindrical ring-like winding body with a diameter and a longitudinal extent in the axial direction results. Most preferably, the windings are wound around and/or in a core made of a ferromagnetic material.

The windings can be formed from one or more electrical conductors with a circular cross section. It is also conceivable that the electrical conductors forming the winding have a cross-sectional shape that deviates from the circular shape, in particular a rectangular shape. Particularly preferably, the windings can be formed from insulated copper foils, which can be wrapped around each other in a similar way to a toilet paper roll.

According to an advantageous further development of the invention, the primary winding can have a higher number of turns than the secondary winding. This means that when the electrical energy is transferred between the primary winding and the secondary winding, a voltage conversion of from the comparatively high battery voltage to the lower rotor voltage.

In this context, it is further preferred that an electrical voltage of 40-1500V, preferably 100-1000V, most preferably 300-850V is applied to the primary winding. Furthermore, in this context, it is preferred that a voltage of 70-500V is applied to the secondary winding.

The primary core and/or the secondary core are/is made from a ferromagnetic material, preferably from a ferrite material. The primary core and/or secondary core can be made in several parts. The respective core parts are preferably constructed essentially rotationally symmetrically, but can contain elements and recesses for fixing or carrying out further components.

Particularly preferably, the primary core and/or the secondary core each have a ring-like spatial shape. Most preferably, the primary core and/or the secondary core have a U-shaped cross-sectional contour with a circumferential groove. The grooves of the U-shaped cross-sectional contours of the primary core and secondary core are preferably directed towards one another. It is also particularly preferred that the primary winding runs in the slot of the primary core and/or the secondary winding runs in the slot of the secondary core.

The cylindrical ring-like secondary winding preferably has a radially outer diameter smaller than 500mm, preferably smaller than 400mm, particularly preferably smaller than 350mm. Most preferably, the radially outer diameter of the cylindrical ring-like secondary winding is chosen between 100-500mm, preferably 150-400mm, most preferably 200-350mm. This allows the centrifugal forces acting during operation to be limited to an advantageous size.

The axial length of the cylindrical ring-like secondary winding is preferably greater than 50%, preferably greater than 70% of the radially outer diameter, especially the diameter of the secondary winding. Such an “elongated” design of the winding has proven to be particularly advantageous for energy transmission inductive transformer proven. To put it simply, flat and elongated designs of the cylindrical ring-like secondary windings have proven to be particularly favorable in terms of the energy transfer properties of the inductive transformer.

It is also highly preferred that the axial length of the cylindrical ring-like primary winding corresponds to between 80-120% of the axial length of the cylindrical ring-like secondary winding, which can also contribute to good energy transfer between the windings.

Furthermore, it is advantageous that the two axial lengths of the cylindrical ring-like windings completely overlap axially, whereby the energy transfer between the primary winding and the secondary winding can be further optimized.

Furthermore, it can be advantageous for the primary core and secondary core to each form surfaces bordering the air gap, via which the magnetic flux is guided from one part to the other. It is advantageous if the surfaces of the primary core bordering the air gap completely cover the surfaces of the secondary core bordering the air gap and/or if the surfaces of the secondary core bordering the air gap completely cover the surfaces of the primary core bordering the air gap, whereby the energy transfer between the primary winding and the secondary winding can be further optimized.

Rectifier electronics can preferably be connected between the secondary winding and a winding of the rotor, so that the secondary winding energizes the winding of the rotor with the interposition of the rectifier electronics.

The primary winding can be rotatably mounted and centered relative to the secondary winding, preferably by means of one or more roller bearings. For this purpose, rolling rolling bodies are arranged between an inner ring and an outer ring of the rolling bearing. The inner ring can be formed from a metallic and/or ceramic material. In principle, it is conceivable to design the inner ring in one piece or in several parts, in particular in two parts. The inner ring can have an inner ring recess. In particular, a cover disk, sealing disk and/or seal can be arranged in an inner ring recess, in particular in a non-positive and/or positive manner. The inner ring recess is preferably designed as a circumferential groove in the inner ring.

The outer ring can be formed from a metallic and/or ceramic material. In principle, it is conceivable to design the outer ring in one piece or in several parts, in particular in two parts. The outer ring can have an outer ring recess. In particular, a cover disk, sealing disk and/or seal can be arranged in an outer ring recess, in particular in a non-positive and/or positive manner. The outer ring recess is preferably designed as a circumferential groove in the outer ring.

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

The rolling elements can roll within the rolling bearing, in particular on the inner ring raceway of the inner ring. For this purpose, the surface of the inner ring raceway can advantageously be designed to be correspondingly abrasion-resistant, for example by means of a corresponding surface treatment process and/or by applying a corresponding additional material layer. The inner ring raceway can be flat or profiled. A profiled design of the inner ring raceway can be used, for example, to guide the rolling elements on the inner ring raceway. A flat shape of the inner ring raceway, on the other hand, can, for example, allow a certain axial displaceability of the rolling elements on the inner ring raceway. The rolling elements can roll within 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 abrasion-resistant, for example by means of a corresponding surface treatment process and/or by applying a corresponding additional material layer. The outer ring raceway can be flat or profiled. A profiled design of the outer ring raceway can be used, for example, to guide the rolling elements on the outer ring raceway. A flat shape of the outer ring raceway, on the other hand, can, for example, allow a certain axial displaceability of the rolling elements on the outer ring raceway.

Rolling elements can be guided in a cage or through rolling element spacers and spaced apart from one another. In principle, it is also conceivable to design a cageless rolling bearing, which is also referred to as a full complement rolling bearing. With full complement rolling bearings, adjacent rolling elements can contact each other.

A rolling bearing can have a cage, with the cage guiding the rolling elements. The cage is designed in such a way that the rolling body balls and/or the rolling body rollers are spaced apart from one another, so that, for example, the friction and heat development of the rolling bodies is 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, whereby an even load distribution can be achieved. The cage can be made in one piece or in several pieces.

A rolling bearing may have a seal to prevent lubricant from leaking out of the rolling bearing or dirt or moisture from entering the rolling bearing. For this purpose, the seals used can be provided with one or more sealing lips, which can rest on a component of the rolling bearing. These are designed in such a way that, on the one hand, they seal the bearing over its entire service life, and on the other hand, the friction caused by the seal is not too high.

The invention further includes a method for assembling a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising the following steps:

• Provision of an inductive transmitter, which has a primary winding that can be energized and a secondary winding spaced therefrom, which can be electrically conductively coupled to a winding of the rotor, and

• Provision of a hollow shaft which can be coupled to the rotor of the electrical machine to transmit torque, and

• Inserting the inductive transmitter into the hollow shaft.

Furthermore, according to a likewise 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, the inner ring being connected in a rotationally fixed manner to the hollow shaft and the outer ring being connected in a rotationally fixed manner to the lance. This can particularly support a modular configuration of the rolling bearing and the hollow shaft. For this purpose, it is then further advantageous that the lance has a first cylinder ring section, on the outer surface of which the primary winding is arranged, and the lance also has a second cylinder ring section arranged coaxially to the first cylinder ring section, on the inner surface of which the outer ring of the rolling bearing is arranged , wherein the first cylinder ring section has a smaller diameter than the second cylinder ring section. Furthermore, the invention can also be further developed in such a way that the rolling bearing, the hollow shaft, the lance and the inductive transmitter form a modular structural unit.

Preferably, a method for assembling a rotor of an electrical

Machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising the following steps:

Provision of a rotor shaft, Provision of a contactless energy transfer device

• Connecting the hollow shaft of the contactless energy transmission device to the rotor shaft,

• Coupling of the secondary winding with a winding of the rotor

The contactless energy transmission device can have rectifier electronics connected to the secondary winding.

In a likewise preferred embodiment variant of the invention, it can also be provided that the contactless energy transmission device has a rectifier electronics, which is also arranged within the hollow shaft and is connected to it in a rotationally fixed manner.

According to a further preferred development of the invention, it can also be provided that the rectifier electronics have a circuit board with electronic components arranged thereon, the circuit board having a substantially circular disk-like or annular disk-like or cylindrical ring-like contour.

In principle, it is also conceivable that the circuit board is not completely closed circumferentially or is formed from several segments. It can therefore also be preferred that the circuit board has a contour similar to a circular disk section, an annular disk section or a cylinder ring section.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the circuit board is connected to the hollow shaft in a cohesive, non-positive and/or positive, rotationally fixed manner. Alternatively, it would also be possible for the rectifier electronics to be accommodated in a housing that has a substantially circular disk-like circular disk section-like or circular disk-like circular disk segment-like or cylinder ring-like cylinder ring segment-like contour and the housing is cohesively, is non-positively and/or positively connected to the hollow shaft in a rotationally fixed manner. The housing can provide additional mechanical, chemical or electromagnetic protection for the rectifier electronics. The housing can be formed, for example, from a plastic or a metallic material. The housing can be made in one piece or in several parts.

The rectifier electronics can also be encased in an electrically non-conductive material.

Furthermore, the invention can also be further developed in such a way that a cooling fluid can flow through the hollow shaft in such a way that heat generated by the rectifier electronics during operation of the contactless energy transmission device can be dissipated by means of the cooling fluid, which promotes particularly low-loss operation of the inductive transmitter.

The invention can also be embodied as a kit-of-parts for producing a contactless energy transmission device for a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle. The kit of parts then includes in particular:

• an inductive transmitter, which has a primary winding that can be energized and a secondary winding that is spaced apart from it and can be electrically coupled to a winding of the rotor,

• a hollow shaft which can be coupled to the rotor of the electric machine to transmit torque,

• rectifier electronics that can be connected to the secondary winding, which can be positioned within the hollow shaft and connected to it in a rotationally fixed manner.

This allows the components required to manufacture the energy transmission device to be made available in a particularly convenient manner. The kit of parts can, for example, be a packaging unit. Furthermore, it is possible to design the kit-of-parts as a compilation of separate storage containers for storing the individual components or the respective component groups of the kit-of-parts.

The invention also includes a method for assembling a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle. Such an assembly process then has, for example, the following steps:

• Provision of rectifier electronics that can be coupled to the secondary winding,

• Inserting the rectifier electronics into the hollow shaft so that the rectifier electronics are connected to the hollow shaft in a rotationally fixed manner,

• Connecting the rectifier electronics to the secondary winding of the inductive transmitter.

According to an advantageous embodiment of the invention, it can be provided that the primary winding and the secondary winding of the inductive transformer are arranged coaxially to one another within the hollow shaft. The advantage of this configuration is that it enables particularly efficient electrical energy transmission.

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

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 configuration is that particularly good cooling of the primary winding can be achieved.

According to a further particularly preferred embodiment of the invention, it can be provided that the contactless energy transmission device has rectifier electronics, which is also arranged within the hollow shaft and is connected to it in a rotationally fixed manner. In principle, the electronics for rectification can be placed anywhere in or on the rotor. However, it is preferred that the electronics for rectification are also positioned inside the hollow shaft, since there are more favorable boundary conditions here in terms of speed stability and thermals.

Furthermore, the invention can also be further developed in such a way that the lance is mounted relative to the hollow shaft by means of a rolling bearing arranged in the hollow shaft. The advantage of this configuration is that a particularly narrow and therefore small annular gap can be formed between the primary coil and the secondary coil.

The object of the invention is further achieved by a kit-of-parts for producing a contactless energy transmission device for a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising an inductive transformer which has a primary winding that can be energized and a secondary winding spaced therefrom which can be electrically conductively coupled to a winding of the rotor, a hollow shaft which can be coupled to the rotor of the electric machine in a torque-transmitting manner, and the secondary winding of the inductive transmitter is arranged within the hollow shaft and connected to it in a rotationally fixed manner is, and a lance which can be inserted axially into the interior of the hollow shaft and on which the primary winding of the inductive transformer is arranged.

The advantage that results from this is, in particular, that the components of the contactless energy transmission device to be assembled can be provided in a particularly convenient manner. The kit-of-parts can be, for example, a packaging unit. Furthermore, it is possible to design the kit-of-parts as a compilation of separate storage containers for storing the individual components or the respective component groups of the kit-of-parts.

According to a further preferred embodiment of the subject matter of the invention, it can be provided that the rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising a contactless energy transmission device according to one of claims 1 -7

Finally, the object of the invention can also be achieved by an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising a rotor according to claim 8.

According to a further preferred development of the invention, it can also be provided that the rectifier electronics have a circuit board with electronic components arranged thereon, wherein the circuit board has a substantially circular disk-like circular disk section-like or circular ring disk-like circular ring disk section-like or cylindrical ring-like cylindrical ring section-like contour. Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the circuit board is connected to the hollow shaft in a materially bonded, force-locking and/or positively locking manner in a rotationally fixed manner. According to a further particularly preferred embodiment of the invention, it can be provided that the rectifier electronics are accommodated in a housing that has a substantially circular disk-like circular disk section-like or circular ring disk-like circular ring disk section-like or cylindrical ring-like has a contour similar to a cylinder ring section and the housing is connected to the hollow shaft in a materially bonded, force-locking and/or form-locking manner so that it cannot rotate. Furthermore, the invention can also be further developed in such a way that a cooling fluid can flow through the hollow shaft in such a way that heat generated by the rectifier electronics during operation of the contactless energy transmission device can be dissipated by means of the cooling fluid.

The object of the invention can also be achieved by a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising a contactless energy transmission device according to one of claims 1-6.

The object of the invention can further be achieved by an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising a rotor according to claim 7.

Finally, the object of the invention can also be achieved by a method for assembling a rotor of an electrical machine, in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising the following steps:

• Provision of a hollow shaft which can be coupled to the rotor of the electric machine in a torque-transmitting manner, and

Inserting the rectifier electronics into the hollow shaft so that the rectifier electronics are connected to the hollow shaft in a rotationally fixed manner, Connecting the rectifier electronics to the secondary winding of the inductive transmitter.

The invention will be explained in more detail below using figures without restricting the general idea of the invention.

It shows:

1 shows an electrical machine with a contactless energy transmission device in a schematic axial sectional representation,

Figure 2 shows a detailed view of the contactless energy transfer device in an axial section,

3 shows a kit-of-parts for producing a contactless energy transmission device for a rotor of an electrical machine,

Figure 4 shows a motor vehicle with an electrical machine in a block diagram,

Figure 5 shows an inductive transformer in a perspective partial sectional view,

Figure 6 shows a first embodiment of an arrangement of rectifier electronics in a hollow shaft in an axial sectional view,

7 shows a second embodiment of an arrangement of rectifier electronics in a hollow shaft in an axial sectional view, 8 shows a third embodiment of an arrangement of rectifier electronics in a hollow shaft in an axial sectional view,

9 shows a fourth embodiment of an arrangement of rectifier electronics in a hollow shaft in an axial sectional view,

Figure 10 shows a fifth embodiment of an arrangement of rectifier electronics in a hollow shaft in an axial sectional view,

Figure 11 shows a sixth embodiment of an arrangement of rectifier electronics in a hollow shaft in an axial sectional view,

12 shows a detailed view of a contactless energy transmission device within a rolling bearing in an axial sectional view,

Figure 13 shows a kit of parts for producing a contactless energy transfer device for a rotor of an electrical machine.

1 shows a contactless energy transmission device 1 for a rotor 2 of an electric machine 3. In the exemplary embodiment shown in FIG. 1, the electric machine 3 is configured as a separately excited synchronous machine for a drive train 23 of a motor vehicle 24, as is also the case in the figure 4 is sketched.

The rotor 2, which is rotatably mounted in the cylindrical ring-like stator 22, has a hollow shaft 4, which is connected to the rotor 2 of the electric machine 3 in a torque-transmitting manner. The rotor 2 also includes a rotor laminated core 18 that is connected to the hollow shaft 4 in a rotationally fixed manner. The hollow shaft 4 thus forms the rotor shaft of the rotor 2. To energize the rotor 2, an inductive transformer 5 is provided, which has an energized primary winding 6 and a secondary winding 7 spaced therefrom, which is electrically conductively coupled to a winding of the rotor 2.

As can be clearly seen from Figure 1, the secondary winding 7 of the inductive transmitter 5 is arranged within the hollow shaft 4 and is rotationally connected to it, while the primary winding 6 of the inductive transmitter 5 is positioned in a rotationally 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 inductive transformer 5 are arranged coaxially to one another within the hollow shaft 4. The primary winding 6 is arranged on a lance 8 which extends axially into the interior of the hollow shaft 4.

Based on Figure 2 it can be clearly seen that the lance 8 can be designed like a cylinder ring and then has an axially extending cooling channel 10 through which a cooling fluid 9 can flow. As a result, the heat loss generated at the primary winding 6 can be dissipated well and efficiently. In the embodiment of the hollow shaft 4 shown in Figure 2, it is designed in two parts and consists of a first hollow cylindrical shaft section 4a and a second hollow cylindrical shaft section 4b, which are connected to one another in a rotationally fixed manner.

In the embodiment variant shown in FIG. 2, the contactless energy transmission device 1 also has rectifier electronics 11, which can also be arranged within the hollow shaft 4 and connected to it in a rotationally fixed manner. In principle, it would also be conceivable to provide a seal between the hollow shaft 4 and the lance 8 in order to protect the inductive transmitter 5 from the ingress of dirt and/or cooling fluid, although this is not shown in the figures.

The rotor laminated core 18 of the rotor 2 is connected in a rotationally fixed manner to the radially outer lateral surface of the hollow shaft 4. The rotor winding head 19 extends from this in the axial direction from the distal end face of the rotor laminated core 18. 2 also shows 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.

3 shows a kit-of-parts 21 for producing a contactless energy transmission device 1 for a rotor 2 of an electrical machine 3, in particular a separately excited synchronous machine within a drive train of a motor vehicle. For example, the kit-of-parts 21 can be used for converting or equipping an electrical machine 3 from a contact-based energization of a rotor 2 to a contactless energization and provides the corresponding equipment components for this purpose.

The kit-of-parts 21 comprises an inductive transformer 5, which has a primary winding 6 that can be energized and a secondary winding 7 spaced therefrom, which can be electrically conductively coupled to a winding of the rotor 2, and a hollow shaft 4 which transmits torque to the rotor 2 of the electrical Machine 3 can be coupled. The secondary winding 7 of the inductive transformer 5 is arranged within the hollow shaft 4 and is connected to it in a rotationally fixed manner. The kit-of-parts 21 also has a lance 8 which can be inserted axially into the interior of the hollow shaft 4 and on which the primary winding 6 of the inductive transformer 5 is arranged. Thus, for example, an existing hollow shaft can then be exchanged and replaced by the hollow shaft of the kit-of-parts 21. The cylindrical ring-shaped lance 8 can then be inserted into the hollow shaft 4, the primary winding 6 and the secondary winding 7 then being aligned coaxially with one another, as is also shown in the assembled state of the lance 8 in FIG. To support the cylindrical ring-shaped lance 8, the rolling bearing 12 is provided as an option in the kit-of-parts 21.

Figure 5 shows a detailed representation of the inductive transformer 5. You can see the primary core 13 and the secondary core 14, each of which has a ring-like spatial shape. Both the primary core 13 and the secondary core 14 have a U-shaped cross-sectional contour with a circumferential cross-section, the grooves of the U-shaped cross-sectional contours of the primary core 13 and secondary core 14 facing each other. The primary winding 6 runs in the groove of the primary core 13 and the secondary winding 7 runs in the groove of the secondary core 14. The primary core 13 and the secondary core 14 are made of a ferromagnetic material, preferably of a ferrite material.

5, the primary winding 6 has a higher number of turns than the secondary winding 7, so that when the electrical energy is transferred between the primary winding 6 and the secondary winding 7, a voltage conversion from the comparatively high battery voltage to the lower rotor voltage is simultaneously realized can be. The two axial lengths of the cylindrical ring-like windings 6, 7 almost completely overlap axially, whereby an optimal and loss-free energy transfer between the primary winding 6 and the secondary winding 7 can be achieved.

6-11 show various options for arranging the rectifier electronics 11 within the hollow shaft 4.

In all embodiments of Figures 6-11, the contactless energy transmission device 1 is connected to the secondary winding 7 with rectifier electronics 11. The rectifier electronics 11 is arranged within the hollow shaft 4 and is connected to it in a rotationally fixed manner.

As shown in Figures 6-11, the secondary winding 7 of the inductive transmitter 5 is preferably also arranged within the hollow shaft 4 and connected to it in a rotationally fixed manner, while the primary winding 6 of the inductive transmitter 5 is positioned in a rotationally rigid manner relative to the hollow shaft 4 in this, but what is not shown in Figures 6-11 for reasons of clarity.

The rectifier electronics 11 has a circuit board 33 with electronic components 34 arranged thereon. In the embodiment of Figure 10, the circuit board 33 has a substantially circular disk-like or circular disk section-like contour, which extends essentially in the radial direction within the hollow shaft 4. 8 shows a similar configuration, in which, however, the circuit board 33 has a circular disk-like or circular disk section-like contour, so that the circuit board 33 can be penetrated and/or flowed through in the axial direction.

9 shows a further possible arrangement of the circuit board 33, in which the circuit board 33 has a cylindrical ring-like or cylindrical ring section-like contour and extends essentially in the axial direction within the hollow shaft 4.

6, 7, 11 show further embodiments of the rectifier electronics 11, in which the rectifier electronics 11 is accommodated in a housing 36, which in turn is connected to the hollow shaft 4 in a material-locking, non-positive and / or positive, rotationally fixed manner. In the embodiment variant of Figure 11, the housing 36 has a substantially circular disk-like or circular disk section-like contour.

The housing 36 can also have a circular disk-like or circular disk-section-like contour, as can also be seen in Figure 6. This means that the housing 36 can be penetrated by the lance 8, for example, or a cooling fluid 9 can flow through it. In the embodiments of Figures 6 and 11, the housing extends like a circular disk essentially in the radial direction. In principle, it is also possible for the housing 36 to extend in the axial direction, as is also shown in Figure 7. In this embodiment, the housing has a cylindrical ring-like or cylindrical ring-section-like contour.

As can also be seen from Figures 6-11, a cooling fluid 9 can flow through the hollow shaft 4 in such a way that heat generated by the rectifier electronics 11 during operation of the contactless energy transmission device 1 can be dissipated by means of the cooling fluid 9. For this purpose, the hollow shaft 4 is also used as Cooling channel 10 is used, through which the cooling fluid 9 can be conveyed axially.

Figure 12 shows an embodiment of the invention, in which the hollow shaft 4 is rotatably mounted relative to a torsionally rigid connection structure 25 by means of a roller bearing 12. In the embodiment shown, the connection structure 25 is the lance 8. The secondary winding 7 of the inductive transmitter 5 is also arranged here within the hollow shaft 4 and is connected to it in a rotationally fixed manner, while the primary winding 6 of the inductive transmitter 5 is positioned in a rotationally rigid manner relative to the hollow shaft 4. In the embodiment variant shown, the primary winding 6 is arranged on a lance 8 which extends axially into the interior of the hollow shaft 4.

The rolling bearing 12 has an inner ring 26 and an outer ring 27, between which a plurality of rolling elements 28 are accommodated, the inner ring 26 being connected in a rotationally fixed manner to the hollow shaft 4 and the outer ring 27 being connected in a rotationally fixed manner to the lance 8.

The lance 8 has a first hollow cylindrical cylinder ring section 29, on the outer surface of which the primary winding 6 is arranged, and the lance 8 further has a second cylinder ring section 30 arranged coaxially to the first cylinder ring section 29, on the inner surface of which the outer ring 27 of the rolling bearing 12 is arranged is, wherein the first cylinder ring section 29 has a smaller diameter than the second cylinder ring section 30. The rolling bearing 12, the hollow shaft 4, the lance 8 and the inductive transmitter 5 form a modular structural unit 31.

Even if it is not shown in Figure 12, the contactless energy transmission device 1 can have rectifier electronics 11, which is also arranged within the hollow shaft 4 and is connected to it in a rotationally fixed manner.

Figure 13 shows another possible kit-of-parts 21 for producing a contactless energy transmission device 1 for a rotor 2 of an electrical Machine 3. It comprises an inductive transmitter 5, which has a primary winding 6 that can be energized and a secondary winding 7 spaced therefrom, which can be electrically conductively coupled to a winding of the rotor 2, and a hollow shaft 4, which transmits torque to the rotor 2 of the electric machine 3 can be coupled. Furthermore, the kit-of-parts 21 has rectifier electronics 11 which can be connected to the secondary winding 7 and which can be positioned within the hollow shaft 4 and connected to it in a rotationally fixed manner.

For example, the following method for assembling a rotor 2 of an electrical machine 3 can be carried out using the kit-of-parts 21 known from FIG. 13. 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 transmitter 5 is provided, which has a primary winding 6 that can be energized and a secondary winding 7 spaced therefrom, which is electrically connected to a winding of the rotor 2 can be conductively coupled. Rectifier electronics 11 that can be coupled to the secondary winding 7 are also provided.

Then the rectifier electronics 11 is inserted into the hollow shaft 4, so that the rectifier electronics 11 is connected to the hollow shaft 4 in a rotationally fixed manner. Finally, the rectifier electronics 11 can then be connected to the secondary winding 7 of the inductive transmitter 5.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be viewed as limiting but rather as illustrative. The following patent claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' features, this designation serves to distinguish two similar features without establishing a ranking. Reference character list

1 energy transfer device

2 rotors

3 electric machine

4 hollow shaft

5 transformers

6 primary winding

7 secondary winding

8 lance

9 cooling fluid

10 cooling channel

11 rectifier electronics

12 rolling bearings

13 primary core

14 secondary core

15 star cap

16 rotor cover

17 housing structure

18 rotor lamination package

19 Rotor winding head

20 rolling bearings

21 kit of parts

22 stator

23 powertrain

24 motor vehicle

25 connection structure

26 inner ring

27 outer ring

28 rolling elements

29 cylinder ring section

30 cylinder ring section

31 unit

32 rotor shaft Circuit board electronic components contour housing

Claims

Expectations

1 . Contactless energy transmission device (1) for a rotor (2) of an electrical machine (3), in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising

• a hollow shaft (4) which can be coupled to the rotor (2) of the electrical machine (3) in a torque-transmitting manner, and

• an inductive transmitter (5) which has a primary winding (6) which can be energized and a secondary winding (7) which is spaced apart from the primary winding and which can be electrically conductively coupled to a winding of the rotor (2), and

• rectifier electronics (11), which is connected to the secondary winding (7), characterized in that the rectifier electronics (11) is arranged within the hollow shaft (4) and is connected to it in a rotationally fixed manner.

2. Contactless energy transmission device (1) according to claim 1, characterized in that the secondary winding (7) of the inductive transmitter (5) is arranged within the hollow shaft (4) and is connected to it in a rotationally fixed manner, while the primary winding (6) of the inductive transmitter ( 5) is positioned in a rotationally rigid manner relative to the hollow shaft (4).

3. Contactless energy transmission device (1) according to claim 1 or 2, characterized in that the rectifier electronics (11) has a circuit board (33) with electronic components (34) arranged thereon, the circuit board (33) having an im Essentially has a circular disk-like or annular disk-like or cylindrical ring-like contour (35). Contactless energy transmission device (1) according to claim 3, characterized in that the circuit board (33) is connected to the hollow shaft (4) in a cohesive, non-positive and / or positive, rotationally fixed manner. Contactless energy transmission device (1) according to one of claims 1-3, characterized in that the rectifier electronics (11) is accommodated in a housing (36) that has a substantially circular disk-like or circular disk-like or cylindrical ring-like contour and the housing (36) is cohesively, is non-positively and/or positively connected to the hollow shaft (4). Contactless energy transmission device (1) according to one of the preceding claims, characterized in that the hollow shaft (4) can be flowed through by a cooling fluid (9) in such a way that during operation of the contactless energy transmission device (1) by the rectifier electronics (11) heat generated by the cooling fluid (9) can be removed. Kit-of-parts for producing a contactless energy transmission device (1) for a rotor (2) of an electrical machine (3), in particular a separately excited synchronous machine within a drive train of a motor vehicle

• an inductive transmitter (5), which has a primary winding (6) that can be energized and a secondary winding (7) spaced therefrom, which can be coupled in an electrically conductive manner to a winding of the rotor (2), • a hollow shaft (4) which can be coupled to the rotor (2) of the electrical machine (3) in a torque-transmitting manner,

• rectifier electronics (11) which can be connected to the secondary winding (7) and which can be positioned within the hollow shaft (4) and connected to it in a rotational manner. Rotor (2) of an electrical machine (3), in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising a contactless energy transmission device (1) according to one of claims 1 -6 Electric machine (3), in particular a separately excited synchronous machine within a drive train of a motor vehicle , comprising a rotor (2) according to claim 8. Method for assembling a rotor (2) of an electrical machine (3), in particular a separately excited synchronous machine within a drive train of a motor vehicle, comprising the following steps:

• Provision of a hollow shaft (4) which can be coupled to the rotor (2) of the electric machine (3) in a torque-transmitting manner, and

• Provision of an inductive transmitter (5), which has an energized primary winding (6) and a secondary winding (7) spaced therefrom, which can be electrically conductively coupled to a winding of the rotor (2), and

• Provision of rectifier electronics (11) that can be coupled to the secondary winding (7),

Inserting the rectifier electronics (11) into the hollow shaft (4), so that the rectifier electronics (11) is connected to the hollow shaft (4) in a rotationally fixed manner, • Connect the rectifier electronics (11) to the secondary winding (7) of the inductive transmitter (5).