DE102020101640A1 - Rotor, method of manufacturing a rotor and electric axial flux machine - Google Patents

Abstract

The invention relates to a rotor (1) for an axial flux machine (2) that can be operated electrically, as a motor and / or as a generator, comprising a carrier (3), a plurality of radially arranged on, on or in the carrier (3) externally extending magnet elements (4), wherein the magnet elements (4) are magnetized in the circumferential direction and are arranged individually or in groups circumferentially with opposite magnetization direction alternately one behind the other. Furthermore, there are a plurality of flux guide elements (5) which conduct the magnetic flux and are arranged on, on or in the carrier (3), circumferentially between the magnetic elements (4). According to the invention, at least one of the flux guide elements (5) arranged circumferentially between two magnet elements (4) is designed in such a way that it only incompletely fills the receiving space (6) formed between two magnet elements (4), so that defined free spaces (7) which are free of flux guide element material, are formed.

Description

The present invention relates to a rotor for an electrical, motor-driven and / or generator-driven axial flux machine, comprising a carrier, a plurality of magnet elements arranged on, on or in the carrier, extending radially from the inside to the outside, and a plurality of, Flux guide elements which conduct the magnetic flux and are arranged on or in the carrier, circumferentially arranged between the magnetic elements. The invention also relates to a method for producing a rotor and an axial flow machine.

From the DE 10 2013 218 829 A1 a rotor for an axial flux machine is already known. In this rotor, the rotor laminations form a type of frame into which inlays are integrated. The rotor laminations have individual punchings for both the magnets and the inlays.

Further structures of rotors for axial flux machines or of axial flux machines themselves are described, inter alia, by the DE 10 2017 204 434 A1 , the DE 10 2005 053 119 A1 , the DE 10 2004 038 884 A1 , the DE 10 2015 208 281 A1 , the DE 10 2017 127 157 A1 or the WO 2018/015293 A1 .

The magnetic flux in an axial flux motor (electric motor) is axially directed in the air gap between the stator and rotor. A laminated rotor for high speeds and frequencies is layered in the axial direction. The axial magnetic flux has to overcome the adhesive layers, as a result of which the magnetic circuit experiences a shear (additional air gap) and loses its efficiency. This in turn causes the engine to lose power. For the axial magnetic flux, SMC (soft magnetic components / soft magnetic powder) is often used, since a 3D flux without significant eddy currents is possible here. A homogeneous SMC rotor is possible for smaller rotors as long as the mechanical load does not exceed the low strength of the SMC.

The invention is based on the object of providing a rotor for an electrical machine, a method for producing a rotor and an electrical axial flux machine, as a result of which the use of magnetic flux conducting material can be further reduced. Expensive SMC material should advantageously be saved.

This object is achieved in each case by the totality of the features of the individual independent claims 1, 8 and 10. Preferred developments of the invention are defined in the subclaims.

A rotor according to the invention for an electrical, motor-driven and / or generator-driven axial flux machine comprises a carrier, a plurality of magnet elements arranged on, on or in the carrier, extending radially from the inside to the outside, and a plurality of on, on or in the carrier arranged circumferentially between the magnetic elements, the magnetic flux conducting flux guide elements. The magnet elements are designed to be magnetized in the circumferential direction and are arranged alternately one behind the other individually or in groups circumferentially with the opposite direction of magnetization. According to the invention, at least one of the flux guide elements arranged circumferentially between two magnet elements is designed such that it only incompletely fills the receiving space formed between two magnet elements, so that defined free spaces that are free of flux guide element material of the flux guide element are formed. This has the advantage that flux guiding material can be saved for the flux guiding elements.

The free spaces are advantageously dimensioned in such a way that the magnetic flux in the air gap, compared to a rotor without free space or with a total space between the magnetic elements completely filled with flux guide material, by a maximum of 20%, preferably by a maximum of 10%, particularly preferably by a maximum of 5 %, in particular by a maximum of 2%, better still by a maximum of 1%.

With regard to the SMC material used, a free space created according to the invention is preferably dimensioned such that it is at least 5%, in particular at least 10%, particularly preferably at least 15%, better still at least 20%, 25% or 30% of the space between two adjacent magnetic elements measures existing overall space. The recess in the SMC material should not exceed 45% of the total volume of the total space between the magnetic elements.

The free space or the recess particularly preferably measures at least 20% and a maximum of 40% of the total installation space. Overall, a material saving compared to a total space completely filled with flux guide material of at least 20% and an associated change in the magnetic field strength in the air gap of a maximum of 10% should be aimed for.

The total space between two adjacent magnet elements is determined by length x width x depth, the length being measured by the radial distance between the inner ring section and the outer ring section, over which the flux guide elements extend radially from the inside to the outside, and the width of the total space by the circumferential, radially from the inside to the outside increasing distance between two adjacent magnet elements is defined, and wherein the depth is essentially determined by the thickness of the rotor or, in the case of a rotor with a rear base plate, by the axial depth up to the base plate. Put simply, the total space is the space that is filled by a flux guide element material that is flush with the thickness of the annular disk-like rotor on the front and rear and is pressed into the space between two adjacent magnet elements. If there is a floor, the depth would be reduced by the thickness of the floor. However, since every component of the rotor can be geometrically delimited by surfaces of almost any shape, the above description is only valid for simple and special arrangements. The rotor can have different thicknesses at each radius, and the magnet can also be designed freely in all dimensions. The recess (volume of the material saving) can also have dimensions that are changed in a radially dependent manner.

• an : Der Träger ist besteht z.B. aus einem innenliegenden Nabenkörper, wobei die Magnete und Flussleitelemente radial außen auf dem Nabenkörper befestigt sind und oder z.B. mittels einem Rings radial auf den Nabenkörper gehalten werden.
• auf: Der Träger hat einen scheibenförmigen Bereich oder radial rausragende Streben oder andere rausragende Tragelemente, auf dem oder auf denen die magnetisch aktiven Bauteile befestigt sind (z.B. Kleben)
• in : Der Träger und die Magnetleitelemente sind ähnlich den Figuren angeordnet.

Among the above-mentioned different alternatives of on, on or in the carrier, the following statements are meant by way of example:

• on: The carrier consists, for example, of an internal hub body, the magnets and flux guide elements being attached to the hub body radially on the outside and / or being held radially on the hub body by means of a ring, for example.
• on: The carrier has a disc-shaped area or radially protruding struts or other protruding support elements on which the magnetically active components are attached (e.g. gluing)
• in: The carrier and the magnetic guide elements are arranged similarly to the figures.

An axial flux machine within the meaning of the invention is characterized in that the magnetic flux generated in the air gap between rotor and stator extends in the axial direction parallel to the axis of rotation of the electrical machine. In other words, the air gap is expanded in a plane that is perpendicular to the axis of rotation of the rotor.

The magnetic flux conducting material is preferably formed from iron powder or from a mixture with iron powder. SMC material is particularly preferably used.

In a particularly preferred embodiment of the carrier, this has an inner ring, via which the rotor can be connected to a shaft in a rotationally fixed manner, and an outer ring which delimits the rotor outward in the radial direction. The carrier can be formed between the inner ring and the outer ring with a bottom part via which the inner ring and the outer ring are connected to one another and which, together with the radial outer ring surface of the inner ring and the radial inner ring surface of the outer ring, provides a receiving space open in the direction of the air gap for receiving the magnetic elements and which forms the flux guide elements of the rotor. It is also possible to design the carrier as a hub construction which extends as far as the inner radius of the magnetic circuit and which is equipped with attached permanent magnets and flux guide pieces. A ring band or some other method (gluing, form fit) then holds the attached permanent magnets and flux guide pieces in position.

In another embodiment of a carrier, a carrier is provided without an outer ring and / or without a base part. The magnet elements and the flux guide elements can be held radially inward by gluing on the carrier. As an alternative or in addition to gluing, the magnetic elements and the flux guiding elements can also be fixed mechanically by claw elements, which are then supported by means of struts on the inner hub-like carrier body.

According to an advantageous embodiment of the invention, it can be provided that the at least one flux guide element has a recess with an axial depth extending over at least a partial area of the radial extent of the flux guide element. The advantage of this configuration is that material recesses can be designed in a structurally simple manner.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the at least one flux guide element is constructed in several parts, in such a way that a recess is formed with an axial depth extending over the radial extent of the flux guide element. For this purpose, several rods of the magnetic flux conducting material, each with a rectangular cross section, can be introduced into the carrier or arranged therein. The advantageous effect of this embodiment is based on the fact that corresponding geometries of magnetic flux guide material can be built up within the carrier with a large number of smaller identical parts.

According to a further preferred further development of the invention, it can also be provided that the recess within the magnetic flux elements is stepped, viewed in the axial direction in cross section, in such a way that it is deeper in the middle area between two magnet elements than in the two laterally adjacent areas of the Recess. The magnetic flux guide elements can be designed in one piece or in several pieces. It can thereby be achieved that further magnetic flux conducting material It is still possible to save without having negative effects on the functionality of the rotor.

The recesses formed can be designed differently and have different cross-sectional shapes. In addition to the cross-sectional shape shown here with a rectangular cross-section or a combination of several rectangles, other cross-sections, such as triangles, semicircles, trapezoids and the like, are conceivable.

Furthermore, the invention can also be further developed in such a way that the carrier has, on its front side facing the air gap, an edge directed radially inward from its outer circumference and / or an edge directed radially outward from its inner ring part for the axial fixation of the flux guide elements and / or which has magnetic elements.

In a likewise preferred embodiment variant of the invention, it can also be provided that the carrier has an annular disk-shaped carrier plate on the bottom side, which has a contour inside the carrier for receiving the flux guide elements, which interacts with the free spaces of the flux guide elements in such a way that a torque-transmitting form fit is formed and the free spaces are preferably completely filled by the bottom contour of the carrier. This means that the free spaces in the magnetic flux guide elements can be replaced by more cost-effective materials on the one hand and that, on the other hand, improved torque transmission is ensured in a structurally simple manner through this form fit between the carrier and the magnetic flux guide material acting in the direction of rotation.

• - Bereitstellen eines Trägers, der mit Vorteil eine ringscheibenförmige Trägerplatte aufweist,
• - Bereitstellen von Magnetelementen und Einbringen der Magnetelemente an, auf oder in den Träger, sowie
• - Einbringen von Flussleitmaterial in die zwischen zwei Magnetelementen innerhalb des Trägers gebildeten Aufnahmeräume, zur Bildung der Flussleitelemente.

The object of the invention is also achieved by a method for manufacturing a rotor, the method comprising the following method steps:

• - Provision of a carrier which advantageously has an annular disk-shaped carrier plate,
• - Provision of magnetic elements and introduction of the magnetic elements on, on or in the carrier, as well as
• Introducing flux guiding material into the receiving spaces formed between two magnetic elements within the carrier to form the flux guiding elements.

The introduction of flux guiding material is advantageously carried out by pressing in SMC material. Alternatively, however, iron powder or SMC material pressed in the form of a rod with a rectangular or square cross-section can also be used. The rods are then simply inserted into the carrier accordingly. Loss protection in the axial direction can be created, for example, by a locking ring which is to be mounted on the outside and / or inside of the carrier and which secures the rod elements in the axial direction against falling out of the carrier.

Finally, the object of the invention can also be achieved by an axial flux machine with a rotor designed according to the invention. The axial flux machine advantageously comprises a rotor with a carrier and with a multiplicity of magnet elements and with a multiplicity of flux guiding elements which conduct the magnetic flux and which are arranged on, on or in the carrier, at least one of the flux guiding elements arranged circumferentially between two magnet elements being designed in this way is that it only incompletely fills the receiving space formed between two magnetic elements, so that defined free spaces that are free of the flux guide element material are formed, as well as at least one first stator with a plurality of coil magnets, which is attached to a first axial rotor side to form a first Air gap is arranged, and which generates a magnetic field which extends substantially in the axial direction in the direction of the rotor. The axial flux machine is particularly preferably designed in an H arrangement and, in addition to two rotors, comprises a stator arranged centrally between these two rotors.

The invention is explained in more detail below with reference to figures without restricting the general inventive concept.

• 1 eine Axialflussmaschine gemäß dem Stand der Technik in Perspektivansicht in schematischer Darstellung, mit einem zwischen zwei Statoren angeordneten Rotor,
• 2 eine weitere Axialflussmaschine gemäß dem Stand der Technik in Perspektivansicht in schematischer Darstellung, in H-Anordnung,
• 3 einen erfindungsgemäßen Rotor in drei unterschiedlichen Perspektivansichten, in einer Darstellung mit Teilschnitt, in schematischer Darstellung,
• 4 zeigt den Verlauf der Magnetfeldlinien für einen abgewickelten (in Umfangsrichtung verlaufenden) Teilschnitt durch ein Motorsegment, für einen Rotor gemäß dem Stand der Technik,
• 5 zeigt den Verlauf der Magnetfeldlinien für einen abgewickelten (in Umfangsrichtung verlaufenden) Teilschnitt durch ein Motorsegment, für einen Rotor gemäß der Erfindung, und
• 6 zeigt eine bevorzugte Ausführungsform eines Magnetflusselements für einen erfindungsgemäßen Rotor in zwei Perspektivansichten in schematischer Darstellung.

Show it:

• 1 an axial flux machine according to the prior art in a perspective view in a schematic representation, with a rotor arranged between two stators,
• 2 a further axial flow machine according to the prior art in a perspective view in a schematic representation, in an H-arrangement,
• 3 a rotor according to the invention in three different perspective views, in a representation with partial section, in a schematic representation,
• 4th shows the course of the magnetic field lines for a developed (running in the circumferential direction) partial section through a motor segment, for a rotor according to the prior art,
• 5 shows the course of the magnetic field lines for a developed (running in the circumferential direction) partial section through a motor segment, for a rotor according to the invention, and
• 6th shows a preferred embodiment of a magnetic flux element for a rotor according to the invention in two perspective views in a schematic representation.

1 shows an axial flux machine according to the prior art in a perspective view in a schematic representation, with a rotor arranged between two stators in its basic structure. The axial flow machine 2 includes a rotor 1 , the one here schematically without its carrier parts but with circumferentially alternating magnetic elements 4th and flux guide elements 5 is shown. In the illustration above is a first stator 11 shown in a plan view from the inside, so that here the individual stator coils of the stator 11 are recognizable. Advantageously, two adjacent stator coils are connected together, with a total of six adjacent stator coils resulting in three stator coil packs, each controlled offset by 120 angular degrees. Would be the first stator 11 , the upper illustration folded down by 180 degrees and forming a first air gap 13th from the rotor 1 kept axially spaced, the unitary compact axial flow machine would result in the assembled state. In the illustration below, a plan view of the remaining stator rotor core is shown, with the second stator 11 , axially through a second air gap 13th spaced, the rotor 1 wearing.

2 shows another axial flow machine 2 according to the prior art in a perspective view in a schematic representation, in an H-arrangement. A centrally arranged stator is axially on both sides 6th with stator coils, each spaced by an air gap 7th , a rotor 1 arranged.

3 shows a rotor according to the invention in three different perspective views, in a representation with partial section, in a schematic representation. From the lower illustration of the 3 as well as from the 5 and 6th it can be seen that the at least one flux guide element 5 to create a free space 7th one extending over at least a partial area of the radial extent of the flux guide element 5 extending recess 8th having with axial depth. The recess 8th is designed stepped seen in the axial direction in cross section, such that it is in the middle area between two magnetic elements 4th is formed axially deeper than in the two laterally adjacent areas of the recess 8th . At the top left is the rotor 1 fully equipped with magnetic elements 4th and shown with flux guide elements. In the view to the right, some areas are not equipped with magnetic elements and flux guide elements, so that the areas in the circumferential direction form a positive fit with the flux guide elements 5 over their recesses 8th interacting and torque-transmitting acting contouring of the carrier base of the carrier 3 is recognizable. The free spaces 7th are due to the bottom contour of the beam 3 completed. The flux guide elements shown here 5 are in one piece and preferably as flux guide elements made from pressed SMC material 5 executed.

the 4th shows the course of the magnetic field lines 1 for a developed partial section (running in the circumferential direction) through a motor segment, for a rotor according to the prior art. The magnetic field lines are shown as they are inside the stator 11 , within the air gap 13th and inside the rotor 1 such an axial flow machine 2 get lost. It can be clearly seen here that there are areas of flux guiding material within the flux guiding elements 5 are, which are essentially without magnetic field lines or in which no magnetic flux is formed. According to the invention, these material areas have been left out, as can be seen from the exemplary embodiment according to the invention.

5 shows in analogy to 4th the course of the magnetic field lines for a developed (running in the circumferential direction) partial section through a motor segment, for a rotor according to the invention. Significant parts of the flow guide material were consciously saved here and by means of appropriately shaped parts of the base plate of the carrier 3 replaced or filled out.

In 6th is a preferred embodiment of a magnetic flux element 5 for a rotor according to the invention 1 Shown in two perspective views in a schematic representation as it is in the rotor 1 like him in 3 is shown, was installed. The magnetic flux guide element 5 is formed in the shape of a circular ring segment and on its base plate of the carrier 3 facing or on its the air gap 13th remote side with radially extending recesses 8th educated. There are the recesses 8th circumferentially expanded in a step-like manner in both directions, the axial thickness of the flux guide element in the expanded lateral areas 5 is larger than in the central area of the recess 8th .

The invention is not limited to the embodiments shown in the figures. The above description is therefore not to be regarded as restrictive, but rather as explanatory. The following patent claims are to be understood in such a way that a named feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. If the patent claims and the above description define “first” and “second” features, this designation serves to distinguish between two similar features without defining an order of precedence.

List of reference symbols

1

rotor

2

Axial flow machine

3

carrier

4th

Magnetic element

5

Flux guide element

6th

Recording room

7th

free space

8th

Recess

9

front

11

stator

12th

Coil magnet

13th

Air gap

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102013218829 A1 [0002]
• DE 102017204434 A1 [0003]
• DE 102005053119 A1 [0003]
• DE 102004038884 A1 [0003]
• DE 102015208281 A1 [0003]
• DE 102017127157 A1 [0003]
• WO 2018/015293 A1 [0003]

Claims (10)

A rotor (1) for an axial flux machine (2) that can be operated electrically, as a motor and / or as a generator, comprising - a carrier (3), - a multiplicity of on, on or in the carrier (3) arranged radially from the inside to externally extending magnetic elements (4), the magnetic elements (4) being magnetized in the circumferential direction and being arranged individually or in groups circumferentially alternately with opposite magnetization direction, - and a plurality of circumferentially arranged on, on or in the carrier (3) between the magnetic elements (4) arranged, the magnetic flux conducting flux guiding elements (5), characterized in that at least one of the flux guiding elements (5) arranged circumferentially between two magnetic elements (4) is designed such that it is the between two magnetic elements (4) within the Carrier (3) formed receiving space (6) only incompletely fills, so that defined free spaces (7) that are free of flux guide elements tmaterial of the flux guide element (5) are formed. Rotor (1) Claim 1 , characterized in that the at least one flux guide element (5) has a recess (8) with an axial depth extending over at least a portion of the radial extent of the flux guide element (5) to form a free space (7). Rotor (1) Claim 2 , characterized in that the recess (8) is stepped in the axial direction such that it is deeper in the middle area between two magnet elements (4) than in the two laterally adjacent areas of the recess (8). Rotor (1) Claim 1 , characterized in that the at least one flux guide element (5) is constructed in several parts, in such a way that a recess (8) extending over the radial extent of the flux guide element (5) and having an axial depth is formed to form a free space (7). Rotor (1) Claim 4 , characterized in that the recess (8) is stepped such that it is formed deeper in the middle area between two magnet elements (4) in the axial direction than in the two laterally adjacent areas of the recess (8). Rotor (1) according to one of the preceding claims, characterized in that the carrier (3) on its front side (9) facing the air gap (13) has a circumferential from its outer circumference directed radially inward and / or circumferentially from its inner ring part radially outwardly facing edge for axially fixing the flux guide elements (5) and / or the magnetic elements (4). Rotor (1) according to one of the preceding claims, characterized in that the carrier (3) has an annular disk-shaped carrier plate on the bottom side, which has a contour in the interior of the carrier (3) for receiving the flux guide elements (5), which corresponds to the free spaces (7 ) the flux guide elements (5) interacts in such a way that a torque-transmitting form fit is formed and the free spaces (7) are preferably completely filled by the contour of the carrier (3) on the bottom. Method for producing a rotor (1), in particular a rotor (1) according to one of the preceding claims, comprising the following method steps: - Provision of a carrier (3), - Provision of magnetic elements (4) and introduction of the magnetic elements (4) on, on or in the carrier (3), - Introducing flux guiding material into the receiving spaces (6) formed between two magnetic elements (4) to form the flux guiding elements (5). Procedure according to Claim 8 , characterized in that the introduction of flux guide material takes place by pressing in SMC material. Axial flux machine (2) which can be operated as a motor and / or generator, characterized in that the axial flux machine (2) has a rotor (1) according to one of the preceding Claims 1 - 7th comprises, the axial flux machine (2) in particular comprises: a rotor (1) with a carrier (3) and with a multiplicity of magnetic elements (4) and with a multiplicity of the magnetic flux conducting flux guide elements (5) which are attached to, on or in the carrier (3) are arranged, wherein at least one of the flux guide elements (5) arranged circumferentially between two magnet elements (4) is designed such that it only incompletely fills the receiving space (6) formed between two magnet elements (4), so that defined Free spaces (7), which are free of the flux guide material of the flux guide element (5), are formed, as well as - a first stator (11) with a plurality of coil magnets (12) which is mounted on a first axial rotor side with the formation of a first air gap (13 ) is arranged, and which generates a magnetic field which extends essentially in the axial direction in the direction of the rotor (1).

Images