AXIAL FLOW MOTOR

Abstract

The present invention describes an axial flux motor (100) with a stator arrangement (102) comprising a plurality of radially arranged stator cores (104), each of the plurality of stator cores (104) comprising a pair of side sections (202) with an arcuate profile. The motor (100) comprises a rotor arrangement (110) arranged adjacent to the stator arrangement (102) about an axis of rotation. The rotor arrangement (110) comprises a plurality of permanent magnets (112) aligned with each pair of side sections (202) of each of the plurality of stator cores (104). The motor (100) comprises a stator winding (106) with a plurality of winding elements (302) which are assembled with the plurality of stator cores (104) such that the plurality of permanent magnets (112) of the rotor arrangement (110) rotate around the axis of rotation when the plurality of winding elements (302) are excited by an electric current.

Description

TECHNICAL AREA

[0001] The present invention relates to electrical machines. In particular, the present invention relates to an axial flux motor. BACKGROUND

[0002] With the increasing demand for electric vehicles (EVs) and other electrified transportation systems, the need for highly efficient and compact electric motors has grown significantly. Electric vehicle powertrains, in particular, benefit from motors that deliver high torque at relatively low speeds while maintaining a compact footprint. Conventional electric motors, especially those with a radial design, have limitations in terms of power density, size, and weight, restricting their use in applications where space and performance are critical, such as in electric vehicles.

[0003] Conventional radial flux motors, in which the magnetic field flows radially from a rotor to a stator, are commonly used in many electric drive applications. Such motors are better suited for installation in passenger vehicles because they have a greater axial length and are therefore more compatible with the available axial space and ground clearance in vehicles. However, the inherent geometry of these motors limits their ability to achieve a high torque-to-weight and energy-to-weight ratio, which is important for efficient and lightweight powertrains.

[0004] Axial flux motors, on the other hand, offer significant advantages over radial designs, as they can deliver higher torque and energy density in a smaller footprint. These motors offer considerably higher torque and a smaller gap between peak and continuous power compared to radial motors. In an axial flux motor, the magnetic field generated by the stator does not flow radially, but parallel to the axis of the motor rotor. However, axial flux motors have a larger diameter relative to their axial length, which can lead to issues with ground clearance, vehicle packaging, and potential impacts with the ground.

[0005] Furthermore, the placement of axial flux motors is limited by the permissible angle of the lateral joint, i.e., the angle at which the motor shaft connects to the rest of the vehicle's mechanical system (transmission), which limits their maximum torque and energy. As more and more original equipment manufacturers (OEMs) adopt axial flux motors, overcoming these torque density limitations becomes increasingly important. Additionally, axial flux motors used in wheel motor applications are restricted by the smallest permissible wheel size, highlighting the need to overcome these design constraints for improved vehicle integration.

[0006] Patent DE102022004617A1 discloses an electric machine with a rotor that is rotatable relative to a rotor axis. The rotor comprises a rotor disk and several magnets arranged circularly on a magnet mounting surface of the rotor disk. The structure of the magnet mounting surface is curved such that a radial outer area extends beyond a radial inner area. In particular, the radial outer area extends beyond the radial inner area in the direction of a stator. However, the curved structure of the rotor disk results in insufficient torque, especially when the electric machine is integrated into a vehicle powertrain that requires a compact design.

[0007] Therefore, there is a need for an axial flux motor that maximizes torque and energy density while reducing the motor diameter to allow for efficient installation in a vehicle. ITEMS OF THE PRESENT INVENTION

[0008] A general object of the present invention is to provide an axial flux motor that addresses the challenges of a balanced relationship between torque, energy density and compactness and enables efficient integration into the powertrain of vehicles.

[0009] One object of the present invention is to provide an axial flux motor with a curved stator core that improves the distribution of the magnetic flux, makes better use of the available space and enables more efficient energy conversion, thereby increasing the torque and energy density of the motor.

[0010] Another object of the present invention is to provide an axial flux motor with improved performance while maintaining a compact form factor suitable for integration into electric powertrains of vehicles where space and performance are critical.

[0011] Another object of the present invention is to provide an efficient, high-performance axial flux motor that increases the overall effectiveness of systems for electric vehicles and contributes to improved range, efficiency and design flexibility. SUMMARY

[0012] Aspects of the present invention relate to an axial flux motor with a curved stator arrangement that improves the distribution of magnetic flux, optimizes space utilization, and increases energy conversion efficiency, resulting in higher torque and energy density. The axial flux motor is also designed to deliver superior performance in a compact form, making it particularly suitable for electric vehicle powertrains where space and performance are critical.

[0013] In one aspect, the present invention discloses an axial flux motor comprising at least one stator assembly, each of which includes a plurality of radially arranged stator cores arranged in a circumferential direction and a corresponding stator winding; and at least one rotor assembly arranged axially adjacent to the at least one stator assembly for rotation about an axis of rotation. Each of the at least one rotor assembly comprises a plurality of radially arranged permanent magnets arranged in a circumferential direction for magnetic interaction with the stator cores of the adjacent at least one stator assembly.

[0014] In one aspect, one of the at least one stator assembly and one of the at least one rotor assembly is positioned between two of the other at least one stator assembly and one of the at least one rotor assembly, and its two side sections have an arcuate profile in a convex shape. Furthermore, at least one side section of each of the other two stator assembly and the stator assembly has an arcuate profile in a corresponding (or matching) concave shape. The matching convex and concave shapes of the side sections of the adjacent rotor and stator assemblies result in a larger interface area for magnetic interaction between them, thus achieving higher performance.

[0015] In another embodiment, a stator arrangement with a convex side section can be assembled between two rotor arrangements with a concave inner side section; or a rotor arrangement with a convex side section can be assembled between two stator arrangements with a concave inner side section.

[0016] According to one embodiment of the present invention, the rotor assembly can comprise at least one rotor body with a plurality of internal pockets for securing the plurality of permanent magnets. The at least one rotor body can be adapted to rotate about the axis of rotation with the rotation of the plurality of permanent magnets about the axis of rotation. The rotor assembly can also comprise a rotor shaft extending along the axis of rotation and rotatably attached to the at least one rotor body.

[0017] According to one embodiment of the present invention, the at least one rotor body can have a plurality of stiffening projections on an outer surface thereof in order to improve the stiffness of the at least one rotor body.

[0018] According to one embodiment of the present invention, each of the several permanent magnets can be secured to the at least one rotor body in order to enclose / surround the corresponding side sections of the several stator cores.

[0019] According to one embodiment of the present invention, the plurality of permanent magnets can be secured to the at least one rotor body in such a way that adjacent permanent magnets of the plurality of permanent magnets have opposite polarity.

[0020] According to one embodiment of the present invention, each of the multiple stator cores can have an upper section and multiple locking extensions suitable for securing the multiple winding elements to the stator core. The stator assembly can comprise a plurality of end caps, each end cap being attached to the upper section of each of the plurality of stator cores.

[0021] According to one embodiment of the present invention, the arc-shaped profile of each of the two side sections of each of the plurality of stator cores can form a section of a circle or an ellipse.

[0022] According to one embodiment of the present invention, each of the multiple permanent magnets can have a curvature that is opposite to the curved profile of each of the pair of side sections of each of the multiple stator cores.

[0023] According to one embodiment of the present invention, each of the multiple stator cores can be formed from multiple curved laminated plates, the diameter of which decreases towards the center of the curved profile.

[0024] According to another embodiment of the present invention, each of the several stator cores can be formed from several flat laminated plates with a reduction in area to an outer surface thereof.

[0025] Various objects, features, aspects and advantages of the subject matter according to the invention will become clearer from the following detailed description of preferred embodiments together with the accompanying drawing figures, in which the same numbers represent the same components. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings serve to further understand the present invention and are an integral part of this description. The drawings illustrate exemplary embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. Fig. 1A and Fig. Figure 1B shows various representations of an axial flux motor according to an embodiment of the present invention; Fig. 2A and Fig. Figure 2B shows exemplary representations of a stator core of a stator arrangement of the axial flux motor according to an embodiment of the present invention; Fig. Figure 3 shows an exemplary perspective view of a winding element of a stator winding of the axial flux motor according to an embodiment of the present invention; and Fig. Figure 4 shows an exemplary front view of the winding element assembled on the stator core of the stator assembly according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] A detailed description of the embodiments of the invention illustrated in the accompanying drawings follows. The embodiments are described in sufficient detail to ensure the invention is clearly understandable. However, the intention is not to limit foreseeable variations of embodiments with the necessary level of detail; on the contrary, the aim is to cover all modifications, equivalents, and alternatives that fall within the scope of the present invention as defined by the accompanying claims.

[0028] The embodiments described here relate to an axial flux motor that effectively overcomes the shortcomings of conventional technology in achieving a balanced ratio between torque, energy density, and compactness, thus enabling efficient integration into vehicle powertrains. The axial flux motor is designed to offer improved performance while maintaining a compact form factor, making it ideal for use in electric vehicle powertrains where space and performance are critical. Ultimately, the present invention provides a high-performance, efficient motor that improves the overall effectiveness of electric vehicle systems and contributes to greater range, efficiency, and flexibility in vehicle design.

[0029] While the exemplary figures and embodiments have been described showing the stator arrangement between two rotor arrangements, wherein the stator arrangement has a convex side section and the two rotor arrangements have a concave inner side section, it is possible to have a rotor arrangement with convex side sections between two stator arrangements whose inner side section is concave, with suitable modifications that are obvious to the person skilled in the art, and all such variations are within the scope of the present invention without any limitations.

[0030] Fig. 1A and Fig. Figure 1B shows an exemplary exploded view and an exemplary sectional view of an axial flux motor (here also referred to as the "motor") 100. The motor 100 is suitable for installation in the front and / or rear electric powertrains of electric vehicles (EVs), including battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and the like. The motor 100 can also be mounted on the chassis of an electric vehicle or used as an electric motor in the wheels. The motor 100 comprises a stator assembly 102 with a plurality of radially arranged stator cores 104. Each stator core 104 comprises a pair of side sections having an arcuate profile. This arcuate profile can form part of a circle or an ellipse, such that each side section of the stator core 104 has a convex shape.

[0031] The motor 100 comprises a stator winding 106, which consists of a plurality of winding elements attached to each stator core 104 of the stator assembly 102. The winding elements can be formed from an electrically conductive material, including at least one made of copper, iron, gold, aluminum, silver, and the like. Each winding element can be connected to an adjacent winding element to form the stator winding 106. The stator assembly 102 can comprise a plurality of end caps 108, as shown in Fig. Figure 1A clearly shows that each end cap 108 is coupled to a stator core 104 of the plurality of stator cores 104 to provide structural integrity to the stator assembly 102 and to insulate the end windings of the winding elements attached to the corresponding stator core 104. In an exemplary embodiment, each of the end caps 108 can be attached to an adjacent end cap 108, so that the stator cores 104 are coupled to each other to form an annular stator assembly 102.

[0032] The motor 100 also includes a rotor assembly 110, which is arranged adjacent to the stator assembly 102 about an axis of rotation. The rotor assembly 110 comprises a plurality of permanent magnets 112 aligned with the stator cores 104 of the stator assembly 102. The rotor assembly 110 may include at least one rotor body 114 for accommodating the permanent magnets 112. In an exemplary embodiment, the rotor assembly 100 comprises a pair of rotor bodies 114, each rotor body 114 having a plurality of internal pockets 116 for accommodating a set of permanent magnets 112 from the plurality of permanent magnets 112, the remaining permanent magnets 112 being attached to internal pockets 116 formed in the other rotor body 114. The permanent magnets 112 are attached to the internal pockets 116 of each rotor body 114, so that adjacent permanent magnets 112 have opposite polarities.Each of the permanent magnets 112 can be secured to the corresponding rotor body 114 to enclose or surround the corresponding side sections of a stator core 104 of the stator arrangement 102.

[0033] In an exemplary embodiment, the permanent magnets 112 can be securely attached to the internal pockets 116 formed in each rotor body 114 by means of adhesives or other permanent bonding agents. Each of the permanent magnets 112 can have a front surface having a shape corresponding to (or opposite to) the curved profile of the stator core 104, and a rear surface opposite the front surface, which is attached to the internal pocket 116 of the corresponding rotor body 114. The front surface of each permanent magnet 112 can face one of the plurality of stator cores 104 of the rotor assembly 102, such that the side sections of the stator core 104 face the permanent magnets 112 attached to the internal pockets 116 of the rotor bodies 114.In an exemplary embodiment, the surface of each of the permanent magnets 112 has a curvature that is opposite to the convex profile of the side section of the corresponding stator core 104.

[0034] The convex profile of each stator core 104 and the concave profile of the surfaces of the permanent magnets 112 enable the motor 100 to have a larger flux interface area for a given maximum diameter of the motor 100. For a given outer diameter of the motor 100, the flux interface area can be significantly increased by optimizing the curved profiles of the stator cores 104 and the end faces of the permanent magnets 112. This increase in the flux interface area leads to an improved distribution of the magnetic flux and higher energy conversion efficiency, thereby increasing the torque and energy density of the motor 100.Furthermore, the curved profiles of the stator cores 104 and the front surfaces of the permanent magnets 112 enable the motor to achieve superior performance while maintaining a compact size, making it particularly suitable for electric vehicle powertrains where packaging and performance are crucial.

[0035] Each of the rotor bodies 114 can have an annular shape and includes a plurality of stiffening projections 118 on its rear side to improve the rigidity of the rotor assembly 110 during its rotation when the stator windings 106 are excited by an electric current. The stiffening projections 118 are formed on the rear / outer surface of each rotor body 114 to maintain its curved shape even at high rotational speeds. As shown in Fig. As shown in Figure 1B, each rotor body 114 can also have a slot 120 extending through the center of the corresponding rotor body 114, allowing a rotor shaft (not shown) to be secured to the rotor body 114. The rotor shaft can extend along the axis of rotation and be non-rotatably connected to each rotor body 114. In an exemplary embodiment, the motor 100 can comprise outer housings 122 that cover the rotor bodies 114 and form an enclosure for the motor 100 components. The rotor bodies 114 and the housings 122 can be provided with cooling channels to ensure that the temperatures of the motor components are kept below a threshold. Each rotor body 114 can be equipped with at least one bearing 124 to support the frictionless rotation of the shaft.

[0036] Fig. 2A and Fig. Figure 2B shows an exemplary perspective view and an exemplary sectional view of the stator core 104 of the stator assembly 102. Each of the side sections 202 of the stator core 104 forms the arc-shaped profile, which is a segment of a circle or an ellipse. The stator core 104 can also include an upper section 204 to which the end cap 108 can be attached to provide structural integrity to the stator assembly 102 and to insulate the end windings of the corresponding winding element attached to the stator core 104.

[0037] In an exemplary embodiment, as in Fig. As clearly shown in Figure 2B, the stator core 104 can be formed from a plurality of curved laminated plates whose diameter decreases towards the center of the curved profile. In another exemplary embodiment, the stator core 104 can be formed from a plurality of flat laminated plates whose area decreases towards the outer surface.

[0038] As in Fig. As shown in Figure 3, each winding element 302 of the stator winding 106 can be made of an electrically conductive material. The winding element 302 can be configured with the stator core 104 such that the side sections 202 of the stator core 104 are exposed to the concave surfaces of the permanent magnets 112, which are attached to the rotor bodies 114 of the rotor assembly 110, with a gap formed between them.

[0039] Fig.Figure 4 shows an exemplary front view of the winding element 302, which is attached to the stator core 104 of the stator assembly 102. The stator core 104 can have a plurality of locking extensions 402 suitable for guiding the winding element 302 of the stator winding 106 and securely holding it to the stator core 104. Each locking extension 402 can be formed over an outer surface of the stator core 104 and have one or more slots through which the winding element 302 of the stator winding 106 can be passed. Once the winding element 302 is attached to the stator core 104, the locking extension 402 can be punched over the outer surface of the stator core 104 to securely lock the winding element 302 to said outer surface.

[0040] When one or more winding elements 302 of the stator winding 106 are excited by an electric current, the winding elements 302 act as electromagnets and generate a magnetic field in the axial direction of the stator cores 104. This magnetic field interacts with the permanent magnets 112, which are attached to the rotor bodies 114 of the rotor assembly 110, such that the S-polarity permanent magnet 112 is attracted to the opposite N-pole of the stator assembly 102. Simultaneously, the S-polarity permanent magnet 112 is repelled by the same S-pole of the stator assembly 102. This results in the generation of a tangential force that causes the rotor bodies 114 to rotate about the axis of rotation.

[0041] The curved profiles of the stator cores 104 and the end faces of the permanent magnets 112 ensure that the axial flux motor 100 offers high torque and high energy density, while minimizing the motor diameter for more efficient integration into a vehicle. By optimizing the curved profiles of the stator cores 104 and the front faces of the permanent magnets 112 according to the specific requirements of vehicle integration, the axial flux motor 100 represents a more compact and powerful solution compared to conventional radial or axial flux motors, enabling better use of space and energy in vehicle powertrains. For example, the curved profiles of the stator cores 104 and the faces of the permanent magnets 112 can be adjusted so that the motor 100 can deliver higher torque at a given outer diameter.Similarly, the curved profiles of the stator cores 104 and the front surfaces of the permanent magnets 112 can be optimized to reduce the diameter of the motor 100 for a given torque output value.

[0042] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention can be developed without deviating from the fundamental scope of the invention. The scope of the invention is defined by the claims that follow. The invention is not limited to the described embodiments, variants, or examples, provided that they are intended to enable a person with ordinary technical knowledge to manufacture and use the invention when combined with information and knowledge available to such a person. ADVANTAGES OF THE PRESENT INVENTION

[0043] The present invention provides an axial flux motor designed to achieve a balance between torque, energy density and compactness, enabling seamless integration into the powertrain of vehicles.

[0044] The present invention provides an axial flux motor with a curved stator core, which improves the distribution of the magnetic flux, optimizes the use of available space and improves the efficiency of energy conversion, resulting in higher torque and energy density.

[0045] The present invention provides an axial flux motor that delivers improved performance while having a more compact design, making it well suited for integration into electric powertrains of vehicles where both space and performance are critical.

[0046] The present invention provides a high-performance, efficient axial flux motor that improves the overall effectiveness of electric vehicle systems, resulting in greater range, efficiency and flexibility in vehicle design. REFERENCE MARK LIST 100 axial flux motor. 102 Stator arrangement. 104 stator cores. 106 stator windings. 108 end caps. 110 Rotor arrangement. 112 permanent magnets. 114 rotor bodies. 116 internal pockets. 118 stiffening projections. 120 slots. 122 cases. 124 warehouses. Section 202. 204 Upper section. 302 Winding element. 402 Locking extension. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102022004617A1

[0006]

Claims

An axial flux motor (100) comprising: at least one stator arrangement (102), each comprising a plurality of radially arranged stator cores (104) arranged in a circumferential direction, and a corresponding stator winding (106); and at least one rotor arrangement (110), which is arranged axially adjacent to the at least one stator arrangement (102) for rotation about an axis of rotation and comprises a plurality of radially arranged permanent magnets (112) arranged in a circumferential direction for magnetic interaction with the stator cores (104) of the adjacent at least one stator arrangement (102); wherein one of the at least one stator arrangement (102) and the at least one rotor arrangement (110) is arranged between two of the other at least one stator arrangement (102) and the at least one rotor arrangement (110), and its two side sections have an arcuate profile in a convex shape;and wherein at least one side section of the other two of the at least one stator arrangement (102) and the rotor arrangement (110) has a curved profile in a matching concave shape, such that the matching convex and concave shapes result in a larger interface area between the at least one stator arrangement (102) and the at least one rotor arrangement (110) to provide higher performance. Axial flux motor (100) according to claim 1, wherein each of the at least one rotor arrangement (110) comprises: at least one rotor body (114) with a plurality of internal pockets (116) for securing the plurality of permanent magnets (112), wherein the at least one rotor body (114) is designed to rotate about the axis of rotation with the rotation of the plurality of permanent magnets (112) about the axis of rotation; and a shaft extending along the axis of rotation and rotatably attached to the at least one rotor body (114). Axial flux motor (100) according to claim 2, wherein the at least one rotor body (114) comprises a plurality of stiffening projections (118) on an outer surface of the same to improve the stiffness of the at least one rotor body (114). Axial flux motor (100) according to claim 2, wherein each of the multiple permanent magnets (112) is secured to the at least one rotor body (114) in order to enclose corresponding side sections (202) of the multiple stator cores (104). Axial flux motor (100) according to claim 2, wherein the multiple permanent magnets (112) are secured to the at least one rotor body (114) such that adjacent permanent magnets (112) of the multiple permanent magnets (112) have opposite polarity. Axial flux motor (100) according to claim 1, wherein: each of the plurality of stator cores (104) comprises: an upper section (204); and a plurality of locking extensions (402) suitable for securing the plurality of winding elements (302) to the stator core (104); and the stator arrangement (102) comprises a plurality of end caps (108), each end cap (108) being attached to the upper section (204) of each of the plurality of stator cores (104). Axial flux motor (100) according to claim 1, wherein the arc-shaped profile of each of the pair of side sections (202) of each of the plurality of stator cores (104) is a section of a circle or an ellipse. Axial flux motor (100) according to claim 1, wherein each of the plurality of permanent magnets (112) has a curvature opposite to the curved profile of each of the pair of side sections (202) of each of the plurality of stator cores (104). Axial flux motor (100) according to claim 1, wherein each of the multiple stator cores (104) is formed from multiple curved laminated plates, the diameter of which decreases towards the center of the curved profile. Axial flux motor (100) according to claim 1, wherein each of the multiple stator cores (104) is formed from multiple flat laminated plates with a reduction of area to an outer surface thereof.

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