DE102021112488A1 - Electrical axial flow machine - Google Patents

Abstract

The invention relates to an electrical axial flow machine (1), comprising a stator (2) and a rotor (3), the rotor (3) having a rotor shaft (30) with at least a first disc-shaped design which can rotate on the rotor shaft (30). and non-displaceably arranged, rotor body (31), wherein the stator (2) comprises a first annular disk-shaped stator body (21) and a second annular disk-shaped stator body (22), which are arranged coaxially to one another and to the rotor shaft (30) and axially with the rotor arranged in between (3) are spaced apart from one another, and a first air gap (32) spaced apart in the axial direction between the first annular disk-shaped stator body (21) and the rotor (3) and a second air gap between the second annular disk-shaped stator body (22) and the rotor (3). Air gap (33) is formed, wherein the first annular disk-shaped stator body (21) has a plurality of openings (23) distributed over the circumference, each of which has a r winding (25) and each of which has a core (24) extending essentially in the axial direction passing through it, with at least the first stator body (21) being mounted on a structural component (26) in a rotationally fixed manner relative to the rotor (3), while the Cores (24) are fixed in the openings (23) outside of the momentum and/or force flow between the first stator body (21) and the structural component (26).

Description

The present invention relates to an electrical axial flux machine, comprising a stator and a rotor, the rotor having a rotor shaft with at least one first rotor body which is designed in the shape of a disk and is arranged on the rotor shaft in a rotationally and non-displaceably fixed manner, the stator having a first annular disk-shaped stator body and a second annular disc-shaped stator bodies, which are arranged coaxially with one another and with the rotor shaft and are axially spaced apart from one another with the rotor being arranged in between, and wherein a first air gap is spaced apart in the axial direction between the first annular disc-shaped stator body and the rotor and a second air gap between the second annular disc-shaped stator body and the rotor Air gap is formed, wherein the first annular disc-shaped stator body has a plurality of openings distributed over the circumference, which are each bordered by a winding and each one is substantially in Axialr direction extending core are penetrated.

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

A detailed description of an electric drive can be found in an article in the ATZ magazine, volume 113, 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 that is arranged concentrically and coaxially with a bevel gear differential, with a switchable 2-speed planetary gear set being arranged in the power train between the electric motor and the bevel gear differential, which is also is positioned coaxially to the electric motor or the bevel gear differential or spur gear differential. The drive unit is very compact and allows a good compromise between climbing ability, acceleration and energy consumption due to the switchable 2-speed planetary gear set. Such drive units are also referred to as e-axles or electrically operable drive train.

In addition to purely electrically operated drive trains, hybrid drive trains are also known. Such drive trains of a hybrid vehicle usually include a combination of an internal combustion engine and an electric motor, and allow - for example in urban areas - a purely electric mode of operation with simultaneous sufficient range and availability, especially for cross-country trips. In addition, there is the possibility, in certain operating situations, to be driven simultaneously by the internal combustion engine and the electric motor.

An axial flux machine is a dynamo-electric machine in which the magnetic flux between the rotor and stator runs parallel to the axis of rotation of the rotor. Often, both the stator and the rotor are largely disc-shaped. Axial flow machines are particularly advantageous when the space available axially is limited in a given application. This is often the case, for example, with electric drive systems for electric or hybrid vehicles.

In addition to the shortened axial length, another advantage of the axial flow machine is its comparatively high torque density. The reason for this is the larger air gap area compared to radial flux machines, which is available for a given installation space. Furthermore, a lower iron volume is required compared to conventional machines, which has a positive effect on the efficiency of the machine. As a rule, an axial flux machine includes at least one stator that has windings for generating the axially aligned magnetic field. At least one rotor is equipped with permanent magnets, for example, whose magnetic field generates a drive torque via an air gap in interaction with the magnetic field of the stator windings.

So-called SMC magnets (Soft Magnetic Composite) are also often used for the permanent magnets mentioned. This material is very brittle and, unlike normal steels, cannot be used with an interference fit, since these SMC parts usually have a low permissible limit stress and show a high risk of fracture, since they are pressed parts made of a powder material. In order not to exceed this limit stress, a positive connection to other parts is unfavorable. However, due to their unfavorable mechanical properties, SMC materials are typically used in parts that are not subject to mechanical loads.

However, for reasons of installation space and mechanical design freedom, these materials are superior to classic laminated stators. Especially in axial flux motors with board design, a design is a iron-core stator as a laminated part unfavorable.

In the prior art mentioned above, the axial flux machines are usually constructed in such a way that the magnetic forces are absorbed via the yoke of the stator and diverted to the housing.

It is now the object of the present invention to provide an electrical axial flux machine in which the risk of breakage of a yoke formed with an SMC material is reduced or completely avoided.

This object is achieved by an electrical axial flow machine, comprising a stator and a rotor, the rotor having a rotor shaft with at least one first disk-shaped rotor body arranged on the rotor shaft in a rotationally and non-displaceably fixed manner, the stator having a first annular disk-shaped stator body and a second annular disc-shaped stator bodies, which are arranged coaxially with one another and with the rotor shaft and are axially spaced apart with the interposition of the rotor, and wherein a first air gap is spaced apart in the axial direction between the first annular disc-shaped stator body and the rotor and between the second annular disc-shaped stator body and the rotor second air gap is formed, wherein the first annular disk-shaped stator body has a plurality of openings distributed over the circumference, which are each bordered by a winding and each one is essentially in the axial direction Device extending core are penetrated, at least the first stator body is rotatably mounted on a structural component with respect to the rotor, while the cores are fixed outside of the torque and / or force flow between the first stator body and the structural component in the openings.

The lack of resilience of cores formed in particular from SMC materials in non-positive connections is avoided in the axial flow machine according to the invention in that instead of a non-force winding and dissipating the forces via the cores, non-force cores are connected to a mechanically resilient coil.

First, the individual elements of the claimed subject matter of the invention are explained in the order in which they are mentioned in the set of claims, and particularly preferred configurations of the subject matter of the invention are described below.

The magnetic flux in an electrical axial flux machine (AFM) according to the invention is directed axially in the air gap between the stator and rotor to a direction of rotation of the rotor of the axial flux machine.

There are different types of axial flow machines. A known type is a so-called I-arrangement, in which the rotor is arranged axially next to a stator or between two stators, and which is claimed by independent claim 1.

Another known type is a so-called H-arrangement, in which two rotors are arranged on opposite axial sides of a stator, and which is claimed with the independent claim 2 on top of it.

In principle, it is also possible for a plurality of rotor-stator configurations to be arranged axially next to one another as an I-type and/or H-type. It would also be possible in this context to arrange both one or more I-type rotor-stator configurations and one or more H-type rotor-stator configurations next to one another in the axial direction. In particular, it is also preferable that the rotor-stator configuration of the H-type and/or the I-type are each configured essentially identically, so that they can be assembled in a modular manner to form an overall configuration. Such rotor-stator configurations can in particular be arranged coaxially to one another and can be connected to a common rotor shaft or to a plurality of rotor shafts.

The rotor of an electrical axial flow machine can preferably be designed at least in parts as a laminated rotor. A laminated rotor is formed in layers in the axial direction. Alternatively, the rotor of an axial flow machine can also have a rotor carrier or rotor body, which is designed to be fitted with magnetic sheets and/or SMC material and with magnetic elements designed as permanent magnets.

A rotor body preferably has an inner part, via which the rotor can be connected to a shaft in a rotationally fixed manner, and an outer part, which outwardly delimits the rotor in the radial direction. The rotor body can be designed with several rotor struts between the inner part and the outer part, via which the inner part and the outer part are connected to one another and which, together with the radial outer surface of the inner part and the radial inner surface of the outer part, form a receiving space for accommodating the magnetic elements and the flux-guiding elements of the rotor forms. alternative to The magnetic elements can be arranged or placed on the rotor carrier in the receiving space.

A magnet element can be in the form of a permanent magnet in the form of a bar magnet or in the form of smaller magnet blocks designed as blocks. The magnetic elements are usually arranged in, on or on a rotor carrier.

The magnetic element, designed as a permanent magnet, of a rotor of an axial flux machine interacts with a rotating magnetic field which is generated by the stator winding coils, which are generally subjected to a three-phase current.

A rotatably mounted shaft of an electrical machine is referred to as a rotor shaft, with which the rotor or rotor body is coupled in a torque-proof manner.

The stator of an electrical axial flow machine preferably has a stator body with a plurality of stator windings arranged in the circumferential direction. Viewed in the circumferential direction, the stator body can be designed in one piece or in segments.

According to an advantageous embodiment of the invention, it can be provided that a first annular disk-shaped stator body and/or a second annular disk-shaped stator body are designed as a printed circuit board, in particular as a printed circuit, which is also referred to as a printed circuit board PCB, which makes the stator body particularly compact and can be produced inexpensively. The winding of the stator body is designed in one piece with the printed circuit board. The printed circuit board is preferably a multilayer printed circuit board with a number of copper layers over which the stator windings extend. Another possible embodiment is the design of the stator body as a sandwich of several multilayer circuit boards. The circuit board is preferably formed from a composite of epoxy resin and glass fiber.

In a likewise preferred embodiment variant of the invention, it can also be provided that the first stator body in the form of a ring disk and/or the second stator body in the form of a ring disk are received in the motor housing in a rotationally fixed manner and are connected to it, so that separate spacer elements between the stators can be dispensed with, for example.

According to a further preferred embodiment of the subject matter of the invention, it can be provided that the motor housing is formed from a metallic material and/or ceramic and/or a plastic and/or from a composite material.

According to a further preferred further development of the invention, it can also be provided that at least the first stator body is designed as a multilayer PCB and/or a plurality of carrier plates are arranged stacked on one another in layers.

Furthermore, according to a likewise advantageous embodiment of the invention, provision can be made for the cores to be formed from a soft-magnetic composite material. In particular, the cores can be formed with an annular body, from which the cores protrude in the axial direction, resulting in a crown-like three-dimensional shape. The cores and the annular body are preferably formed monolithically.

According to a further particularly preferred embodiment of the invention, provision can be made for the cores to be fixed in the openings in a form-fitting and/or force-fitting and/or cohesive manner. Furthermore, the invention can also be further developed in this connection to the effect that the cores are fixed in the openings by means of an adhesive connection. The force release of the soft-magnetic cores thus occurs via a form-fitting adhesive connection between the tooth-like cores of the yoke and the stator board or the carrier plate. The adhesive connection is preferably placed in such a way that the forces are dissipated from the cores as close as possible to the point of origin, i.e. the air gap between rotor and stator.

In a likewise preferred embodiment variant of the invention, provision can also be made for the adhesive connection to be elastic, as a result of which a more even transmission of force between the openings and the cores can be brought about.

It can also be advantageous to further develop the invention in such a way that the first stator body has receiving structures for receiving the adhesive of the adhesive connection in the area of the openings and/or the cores. In order to produce the force generation close to the force dissipation, adhesive pockets for receiving the adhesive can be introduced into the soft magnetic cores in a targeted manner. Thus, a force-free joining of the sensitive soft magnetic cores is possible.

According to a further preferred embodiment of the subject matter of the invention, it can be provided that the structural component is a motor housing of the axial flow machine.

Finally, the invention can also be implemented in an advantageous manner such that the first stator body and the second stator body are of essentially identical design, which reduces the complexity of the components and lowers the production costs.

The invention will be explained in more detail below with reference to figures without restricting the general inventive idea.

• 1 eine perspektivische Explosionsdarstellung einer Axialflussmaschine,
• 2 einen Stator der Axialflussmaschine in einer ersten Axialschnittansicht, und
• 3 einen Stator der Axialflussmaschine in einer zweiten Axialschnittansicht.

Show it:

• 1 a perspective exploded view of an axial flow machine,
• 2 a stator of the axial flow machine in a first axial section view, and
• 3 a stator of the axial flow machine in a second axial section view.

the 1 shows an electrical axial flow machine 1, comprising a stator 2 and a rotor 3, the rotor 3 having a rotor shaft 30 with at least one first rotor body 31, which is designed in the shape of a disk and is arranged on the rotor shaft 30 in a rotationally and non-displaceably fixed manner.

The stator 2 has a first annular disk-shaped stator body 21 and a second annular disk-shaped stator body 22 which are arranged coaxially with one another and with the rotor shaft 30 and are axially spaced apart from one another with the rotor 3 being arranged therebetween. A first air gap 32 is formed at a distance in the axial direction between the first annular disk-shaped stator body 21 and the rotor 3 , and a second air gap 33 is formed between the second annular disk-shaped stator body 22 and the rotor 3 . At least the first stator body 21 is designed as a printed circuit board PCB, in which the winding of the stator body 21 is formed in one piece with a carrier plate 27 .

The first annular disk-shaped stator body 21 has a plurality of openings 23 distributed over the circumference, each of which is bordered by a winding 25 and each by a core 24 that extends essentially in the axial direction and extends out of an annular base body in the axial direction. be attacked. At least the first stator body 21 is mounted non-rotatably relative to the rotor 3 on a structural component 26 designed as a housing ring 4, while the cores 24 are fixed in the openings 23 outside of the torque and/or force flow between the first stator body 21 and the structural component 26. The first stator body 21 and the second stator body 22 are of essentially identical design. The cores 24 are formed from a soft-magnetic composite material, which are fixed in the openings 23 by means of an elastic adhesive connection 28 .

From the 2-3 it can be seen that the first stator body 21 in the area of the openings 23 and/or the cores 24 have receiving structures 29 for receiving the adhesive of the adhesive connection 28 . The receiving structures 29 can be designed, for example, as pockets, areas of increased surface roughness, engravings or the like.

the 2 shows an axial sectional view through the first stator body 21, along the radially extending webs between two circumferentially adjacent openings. In this sectional view, one can see the ring-shaped section of a core 24 which is connected to the carrier plate 27 in a cohesive manner with a radially running adhesive connection 28 .

the 3 shows an axial sectional view through the first stator body 21, along a sectional plane through an opening 23. It can be seen here that a core 24 penetrates the opening 23 completely axially and has adhesive connections 28 extending in the axial direction along its lateral surface.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered as limiting but as illustrative. The following patent claims are to be understood in such a way that a mentioned 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' feature, this designation serves to distinguish between two similar features without establishing a ranking.

Reference List

1

axial flow machine

2

stator

3

rotor

4

housing ring/motor housing

21

stator body

22

stator body

23

openings

24

core

25

winding

26

structural component

27

backing plate

28

adhesive connection

29

receiving structures

30

rotor shaft

31

rotor body

32

air gap

33

air gap

Claims (10)

Electrical axial flux machine (1), comprising a stator (2) and a rotor (3), the rotor (3) having a rotor shaft (30) with at least a first disc-shaped design arranged on the rotor shaft (30) in a rotationally and non-displaceably fixed manner, Rotor body (31), wherein the stator (2) comprises a first annular disk-shaped stator body (21) and a second annular disk-shaped stator body (22) which are arranged coaxially to one another and to the rotor shaft (30) and axially to one another with the rotor (3) being arranged in between are spaced apart, and a first air gap (32) spaced apart in the axial direction between the first annular disk-shaped stator body (21) and the rotor (3) and a second air gap (33) between the second annular disk-shaped stator body (22) and the rotor (3) is formed, wherein the first annular disc-shaped stator body (21) has a plurality of openings (23) distributed over the circumference, which are each bordered by a winding (25). and are each penetrated by a core (24) extending essentially in the axial direction, characterized in that at least the first stator body (21) is mounted on a structural component (26) in a rotationally fixed manner relative to the rotor (3), while the cores (24 ) are fixed outside of the torque and / or force flow between the first stator body (21) and the structural component (26) in the openings (23). Electrical axial flow machine (1) after claim 1 , characterized in that at least the first stator body (21) is designed as a printed circuit board PCB, in which the winding of the stator body (21) is integrally formed with a support plate (27). Electrical axial flow machine (1) after claim 1 or 2 , characterized in that at least the first stator body (21) is designed as a multilayer PCB and/or a plurality of carrier plates (27) are arranged stacked on one another in layers. Electrical axial flow machine (1) according to one of the preceding claims, characterized in that the cores (24) are formed from a soft-magnetic composite material. Electrical axial flow machine (1) according to one of the preceding claims, characterized in that the cores (24) are fixed in the openings (23) in a form-fitting and/or force-fitting and/or cohesive manner. Electrical axial flow machine (1) according to one of the preceding claims, characterized in that the cores (24) are fixed in the openings (23) by means of an adhesive connection (28). Electrical axial flow machine (1) after claim 6 , characterized in that the adhesive connection (28) is elastic. Electrical axial flow machine (1) after claim 6 or 7 , characterized in that the first stator body (21) in the region of the openings (23) and/or the cores (24) have receiving structures (29) for receiving the adhesive of the adhesive connection (28). Electrical axial flow machine (1) according to one of the preceding claims, characterized in that the structural component (26) is a motor housing (4) of the axial flow machine (1). Electrical axial flow machine (1) according to one of the preceding claims, characterized in that the first stator body (21) and the second stator body (22) are of essentially identical design.

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