Axial flux machine rotor

Abstract

The invention relates to a manufacturing method of a rotor of an axial magnetic flux permanent magnet machine, and the axial magnetic flux permanent magnet machine is provided with a stator which comprises a group of coils which are wound on each stator bar and are circumferentially arranged at intervals around the axis of the axial magnetic flux permanent magnet machine; and a rotor comprising a rotor body on which is disposed a set of permanent magnets located on one layer of the metal laminate and rotatably mounted about the axis, in which the rotor and stator are spaced apart from each other along the axis to form a gap therebetween, the magnetic flux in the axial magnetic flux permanent magnet machine is generally in an axial direction within the gap, the method comprising: brazing the metal laminate to the rotor body; and combining the group of permanent magnets with the metal laminated body.

Description

Technical Field

[0001] This specification describes a method for manufacturing an axial flux permanent magnet machine rotor, a rotor manufactured by the method, and a machine incorporating the rotor. Background Art

[0002] Axial flux permanent magnet machines usually have a disc-shaped or ring-shaped rotor structure and a stator structure arranged around an axis. The stator includes a set of coils, each of which can be parallel to the axis. The rotor is mounted on bearings and has a set of permanent magnets, which are bonded to the rotor by adhesive. The bearings allow the rotor to rotate around the axis driven by the magnetic field of the stator coils.

[0003] Figure 1a The general structure of an axial flux machine is shown, in which a pair of rotors R1, R2 are provided on both sides of a stator S. However, in a simple structure, one of the rotors can be omitted. An air gap G is provided between the rotor and the stator, and in the axial flux machine, the direction of the magnetic flux passing through the air gap is substantially axial.

[0004] Axial flux permanent magnet machines have various structures depending on how the north and south poles of the rotor are set. Figure 1b Shown are the basic structures of the opposite polarity torus (Torus-NS), the same polarity torus (Torus-NN) (this same polarity arrangement requires the flux to flow through the thickness of the yoke, thus having a thicker yoke), and the yokeless segmented armature (YASA) topology. The sub-diagram of the YASA topology shows a cross section of two coils, where the cross-hatched area represents the windings around each coil.

[0005] As described above, in known axial flux permanent magnet machines, permanent magnets are bonded to the structural body of the rotor by an adhesive, such as a polymer adhesive. The adhesive helps to hold the magnets relatively in place, and can also electrically isolate the magnets from the rotor body, thereby reducing eddy currents. Eddy currents can lead to increased heat generation and reduced efficiency. In order to further reduce eddy currents in the rotor body, an intermediate layer of laminated electrical steel sheets can be provided between the magnets and the rotor structural body. Accordingly, the magnets are bonded to the laminate by an adhesive, and the laminate itself is bonded to the rotor body by an adhesive. Among them, the laminate and two adhesive layers electrically isolate the magnets from the rotor body, thereby reducing eddy currents.

[0006] In the YASA topology, while the adhesive bond does a good job of holding the magnets in place and reducing eddy currents, the adhesive bond will be subject to significant stress and strain under the high temperatures and speeds that may exist, increasing the risk of component failure. For example, the bond may crack or otherwise break, shortening the life of the rotor.

[0007] In addition, the adhesive bond between the laminate and the rotor body is often electrically insulating. While this is generally not a problem in most applications, when the laminate surfaces are made coplanar by certain types of machining such as grinding, lathing or milling, such machining can cause the exposed surfaces of the laminate layers to fuse or smear with the machined surfaces, greatly reducing the laminate's ability to prevent eddy currents, and the laminate's electrical isolation also limits subsequent deburring. Therefore, once the laminate surface is bonded to the rotor body by the adhesive, it is difficult to machine it. In addition, any machining and deburring has to be completed before the laminate is bonded to the rotor, which is difficult to achieve in practice.

[0008] US20040250408A1 proposes a method for winding a soft magnetic metal strip into a ring-shaped body and mechanically constraining the metal strip by applying an adhesive to overcome the problems existing in wire-cut electrospark machining, electrochemical grinding, conventional electrospark machining, cutting, stamping acid etching and fine blanking.

[0009] US2004150285A1 proposes a method in which multiple layers of amorphous metal strips are laminated together by bonding to form a substantially three-dimensional component. According to the text, the structural integrity achieved by the bond is sufficient to enable the component to be handled and used, or incorporated into a larger structure. US2004150285A1 emphasizes that since it is difficult to remove burrs or other edge defects without causing damage to the laminated structure (for example, it may cause material smearing on or near the surface after cutting), the formation method of each laminate is preferably not to produce such burrs or edge defects. Summary of the invention

[0010] In general, the adhesive bonding problem between the electrical steel laminate and the rotor body in the YASA topology is overcome by replacing the adhesive bonding between the rotor body and the laminate with a brazed bond. Brazed bonding is stronger than adhesive bonding, more difficult to crack, and has higher rigidity, so it can withstand higher temperatures and speeds for a longer time without failure compared to the practice of bonding the laminate to the rotor body by an adhesive. In addition, the higher rigidity and bonding strength work together to enable the processing for achieving coplanarity to be performed with higher strength and faster speed. In addition, since the brazed bond is metal and conductive, an electrically enhanced chemical etching process such as electrochemical machining (ECM) can be subsequently performed to remove the laminate that is accidentally fused or smeared with material due to mechanical processing. Unlike many other processing processes, electrically enhanced etching processes such as ECM are suitable for implementation on the production line. Therefore, brazed bonding can not only increase the strength and rigidity of the rotor, but also enable the use of more efficient processing processes on the production line. This method is completely different from the known method based on the principle of reducing eddy currents by electrically isolating the laminate (e.g., by an adhesive). The inventors have realised that any eddy current enhancement that may result from the use of a brazed bond is offset by the significant increase in bond strength and the advantages of being able to use more efficient processing techniques such as ECM. In addition, when metal laminates are bonded by adhesives, interlayer separation may occur in the metal laminates, resulting in the possibility of damage to the laminated structure. The rigidity of the brazed bond between the laminate and the rotor body can reduce such possibilities. Specifically, compared to the practice of bonding the laminate to the rotor body by adhesive, the high rigidity of the brazed bond of the rotor body can reduce the relative movement between the layers when processing the laminated surface, thereby significantly increasing the forces that each layer can withstand. In this way, processing can be performed after the laminate is bonded to the rotor body, thereby simplifying the manufacturing process.

[0011] For example, the surface of the stack facing away from the rotor body may be machined in an initial machining step by lathing, milling, grinding and / or dry ice blasting. However, by using brazing bonding, the advantage of enabling such a step to be followed by, or even replaced by, an ECM is achieved, so that the surface has high coplanarity, smoothness and cleanliness before a set of permanent magnets are bonded to the surface, while not causing damage to the high-precision stack structure. By achieving coplanarity and higher smoothness and cleanliness of the surface between the stack and the permanent magnets, the performance and life of the rotor can be improved, the physical integrity of the stack is increased, and the electrical isolation between the turns of the stack (i.e., between the layers of the stack structure) and between the stack and the attached magnets is improved, thereby helping to reduce eddy currents in the rotor body. In contrast, if machining is performed directly on the surface of the stack bonded to the rotor body by an adhesive, due to the lack of rigidity of the stack, severe damage may be caused to the machined surface of the stack structure, and at least many of the advantages of the ECM cannot be achieved. Therefore, the only viable options for adhesive-based methods are either low-intensity machining techniques that reduce the smoothness and increase the contamination of the surface to be bonded to the permanent magnets, or no machining at all, resulting in substandard rotor performance and life.

[0012] Therefore, according to the first aspect, a method for manufacturing an axial flux permanent magnet machine rotor is provided, wherein the axial flux permanent magnet machine comprises: a stator, which includes a group of coils wound on each stator wire rod and arranged circumferentially around the axis of the machine; and a rotor, which includes a rotor body, on which a group of permanent magnets are arranged, the group of permanent magnets are located on a layer of a metal laminate and are installed in a manner that can rotate around the axis, wherein the rotor and the stator are separated from each other along the axis to form a gap between the two, and the magnetic flux in the axial flux permanent magnet machine is generally along the axial direction in the gap, and the method comprises: brazing the metal laminate to the rotor body; and combining the group of permanent magnets with the metal laminate.

[0013] Optionally, the method comprises: after brazing the metal laminate to the rotor body and before bonding the set of permanent magnets, electrochemically machining a surface of the metal laminate to deburr the surface.

[0014] As described above, unlike other deburring methods, ECM has the following advantages: before the set of permanent magnets are bonded to the surface, the surface is made to have high coplanarity, smoothness and cleanliness, while not causing damage to the highly precise laminated structure; and it is extremely suitable for implementation on a production line.

[0015] Optionally, the method includes applying a filling compound to the metal stack to fill interlayer gaps of the metal stack.

[0016] Filling the interlayer gaps after the metal stack is combined with the rotor body has the advantage of further increasing the rigidity of the stack by sandwiching each stack between layers of filling compound. This not only further improves the stack's ability to withstand the large rotational forces and high temperatures generated when the YASA topology is operated, but also enables the stack to withstand greater forces during any subsequent processing. In addition, the filling compound prevents the stack from being trapped between the layers of cutting fluid such as oil or other processing fluids during processing. In other words, the filling compound seals and electrically isolates adjacent layers from each other.

[0017] Optionally, said applying of the filling compound comprises vacuum pressure impregnation (VPI) with a resin.

[0018] VPI is a resin transfer molding process in which the rotor body together with the metal laminate brazed thereon is completely immersed in a resin and the resin is forced into the interlayer gaps (i.e., impregnated therein) by a combination of dry and / or wet vacuum and / or pressure cycles to obtain an integral structure comprising the resin and the metal laminate. The VPI process may, for example, include: placing the rotor body together with the laminate bonded thereto in a closed tool; evacuating; and injecting the resin (optionally under pressure) into the tool so that it penetrates into the interlayer gaps. Subsequently, the resin is cooled and hardened to form an integral structure. The VPI process has the following advantages: it ensures that the resin impregnation is diffused throughout most of the laminate structure (if not the entire structure) without leaving any gaps. In this way, not only can the stiffness of the metal laminate be improved as described above, but any contaminants can also be prevented from entering the interlayer gaps, thereby improving the performance of the rotor.

[0019] Optionally, the brazing comprises: applying a brazing compound on the surface of the rotor body; placing the metal laminate on the brazing compound on the rotor body; and heating the brazing compound to bond the metal laminate to the rotor body. Optionally, the heating is performed by a humpback furnace or a vacuum brazing furnace.

[0020] In a preferred embodiment, the rotor body is disc-shaped with a central axial through hole, and the side edges of one or two main surfaces of the rotor body can be raised to form a concave shape for accommodating the stack. In this way, the concave shape has the advantage that the automatic equipment on the production line can deposit the brazing compound such as brazing powder in the space provided by it. After the brazing compound is deposited on the rotor body, the metal stack can be placed thereon, wherein the raised edges help to keep the metal stack precisely in place. After the stack is placed on the rotor body in a manner such that the brazing compound is sandwiched, the brazing compound is melted by heating, thereby brazing the stack to the rotor body to connect the two to each other. In a preferred embodiment, a camelback furnace or a vacuum brazing furnace can be used as a link in the production line for implementing the method of the present invention.

[0021] Optionally, the method may include quenching and tempering the rotor body and the bonded metal laminate. Optionally, the quenching includes gas quenching.

[0022] The practice of quenching and tempering the rotor body and the attached metal laminations has the advantage of ensuring that the desired metal grain structure is achieved. In an advantageous embodiment, by quenching in a gas rather than an oil, etc., it is ensured that there is no contamination between the layers of the lamination structure, which would otherwise reduce the performance and life of the rotor.

[0023] Optionally, the method may include: flattening the rotor body and the metal laminate, for example by flattening, to compensate for deformation that may occur during the brazing process or during the heat treatment cycle after the quenching and tempering. The flattening process is a process of plastically deforming the assembly, and therefore may accordingly include: bending the rotor body and the metal laminate to a predetermined shape, such as a flat shape.

[0024] Optionally, before combining the metal laminate with the rotor body, the method includes: identifying a surface of the metal laminate that is flatter than another surface of the metal laminate, wherein the brazing is performed on the identified flatter surface.

[0025] Within the contemplated scope of the present invention, the metal stack is generally manufactured by winding a metal sheet into a metal coil. This process makes one side of the metal stack smoother or flatter than the other side. The inventors have realized that brazing on the flattest or smoothest surface can greatly improve the bonding strength with the rotor body, thereby further enhancing and achieving the advantages of the higher rigidity laminate structure described above. Therefore, identifying the smoothest surface of the metal stack and brazing on this surface has the advantage of improving rotor performance.

[0026] Optionally, after the metal laminate is brazed to the rotor body, the permanent magnet is bonded to the metal laminate by an adhesive.

[0027] According to a second aspect, an axial flux permanent magnet machine is provided, comprising: a stator, the stator comprising a group of coils respectively wound around each stator wire rod and circumferentially spaced around the axis of the axial flux permanent magnet machine; and a rotor, on which a group of permanent magnets are arranged, the group of permanent magnets are located on a layer of a metal laminate and are installed in a manner that can rotate around the axis, wherein the rotor and the stator are separated from each other along the axis to form a gap therebetween, and the magnetic flux in the axial flux permanent magnet machine is generally along the axial direction in the gap, wherein the rotor comprises: a rotor body; and a brazing connection between the metal laminate and the rotor body.

[0028] Optionally, the metal stack comprises an electrochemically processed surface.

[0029] As described above, the electrochemically machined surface is highly coplanar, smooth and clean, thus improving rotor performance and life, increasing the physical integrity of the stack, and improving electrical isolation between turns and with the incorporated magnets, thereby helping to reduce eddy currents within the rotor body, compared to metal stack surfaces machined by other techniques.

[0030] Optionally, the axial flux permanent magnet machine includes a filling compound, such as a resin, disposed in the interlaminar gaps of the metal laminate.

[0031] Optionally, the axial flux permanent magnet machine comprises an adhesive bond between the metal laminate and the set of permanent magnets; and the metal laminate.

[0032] It should be understood that the axial flux permanent magnet machine described herein has all the advantages described above in conjunction with the above method. These advantages are derived from: greater strength and stiffness, electrical conductivity due to the brazed bond between the metal stack and the rotor body, and / or filler compounds within the metal stack.

[0033] According to a third aspect, there is provided an axial flux permanent magnet machine rotor comprising: a rotor body provided with a group of permanent magnets located on a layer of a metal laminate; and a brazed bond between the metal laminate and the rotor body.

[0034] It should be understood that the rotor described herein has all the advantages described above in conjunction with the above method. These advantages are derived from: greater strength and stiffness, electrical conductivity due to the brazed bond between the metal stack and the rotor body, and / or filler compounds within the metal stack.

[0035] According to a fourth aspect, a method for bonding a metal laminate to a rotor body of a rotor is provided, the method comprising: applying a brazing compound on a surface of the rotor body; placing the metal laminate on the brazing compound on the rotor body; and heating the brazing compound to bond the metal laminate to the rotor body.

[0036] Optionally, the method comprises: after brazing the metal laminate to the rotor body, electrochemically machining a surface of the metal laminate to deburr the surface.

[0037] Optionally, the method includes applying a filling compound to the metal stack to fill interlayer gaps of the metal stack.

[0038] In an advantageous embodiment, the method of the invention is not limited to manufacturing the above-mentioned axial flux permanent magnet machine rotor, but can also be generally used to bond a metal laminate to a rotor body of any type of rotor to achieve the above-mentioned advantages.

[0039] According to a fifth aspect, a method for processing a metal stack is provided, the method comprising: performing electrochemical processing on a surface of the metal stack.

[0040] In an advantageous embodiment, the method of the invention is not limited to manufacturing the above-mentioned axial flux permanent magnet machine rotor, nor is it limited to bonding metal laminates to rotors. In particular, the method can achieve the above-mentioned advantages when it is generally used to process any metal laminate.

[0041] For example, the method can be particularly used to efficiently deburr and smooth the surface of a disc-shaped or annular metal laminate (wherein each metal laminate extends parallel to and / or around the axis) made by winding a metal sheet around a central axis. Therefore, the method is particularly suitable for situations where it is desired to ensure that the laminates are not bonded, that material is not smeared, or that they are not otherwise fused together. In other words, the method is particularly effective in preventing material smearing or damage to the processed surface that may be caused by other processing or deburring methods. Such metal laminates can be used not only in motors, generators, other magnetic machines and their components, but also in other equipment and systems. Therefore, the above-mentioned metal laminates mentioned in the present method can, for example, refer to metal laminates in motors, generators and / or other magnetic machines.

[0042] The above-mentioned axial flux permanent magnet machine and the axial flux permanent magnet machine used in the above-mentioned method may be, for example, an electric motor or a generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and other aspects of the present invention are further described below by way of example only with reference to the accompanying drawings. In the drawings:

[0044] Figure 1a to Figure 1c Shown are the general structure of a dual-rotor axial flux machine and an exemplary topology of an axial permanent magnet machine, including a side view schematic diagram of a yokeless segmented armature (YASA) machine and an enumeration diagram of a YASA machine.

[0045] Figure 2 for Figure 1c A perspective view of the YASA machine shown.

[0046] Figure 3 This is an exploded perspective view of the stator and stator casing of the YASA machine.

[0047] Figure 4 This is an exploded view of the rotor of the axial flux permanent magnet machine of the present invention.

[0048] Figure 5a Shown is the metal laminate 403 bonded to the rotor body after a brazing process.

[0049] Figure 5b For along Figure 5a Cross-sectional view along line AA.

[0050] Figure 6a Shown is an example VPI tool.

[0051] Figure 6b A partial cross-sectional view of the rotor body and metal laminate after application of the filling compound.

[0052] Figure 7 It is a cross-sectional view of the assembled rotor of the present invention.

[0053] Figure 8 The method of the present invention is shown.

[0054] Fig. 9 The method of the present invention is shown.

[0055] Fig.10 The method of the present invention is shown.

[0056] In the drawings, similar elements are denoted by similar reference numerals. DETAILED DESCRIPTION

[0057] Figure 1c , Figure 2 and Figure 3 Extracted from WO2012022974, where: Figure 1c Detailed view of an exemplary Yokeless Segmented Armature (YASA) machine 10. The YASA machine 10 can function as both a motor and a generator.

[0058] The YASA machine 10 includes a stator 12 and, in this example, two rotors 14a, 14b. The stator 12 includes a set of individual stator bars 16 spaced circumferentially about a machine axis 20, which also forms the axis of the rotors 14a, 14b. Each stator bar 16 is provided with a stator coil 22 and has an axis generally arranged parallel to the axis of rotation 20. Each end 18a, 18b of the stator bar is provided with a pole shoe 27, which helps to confine the individual coils within the stator coil 22 and allows the magnetic field generated by the stator coil to propagate. The stator coil 22 can be made of square or rectangular cross-section wire after insulation treatment to achieve a higher filling factor. In the case of an electric motor, the stator coil 22 is connected to an electrical circuit (not shown) that energizes the coil so that the magnetic field generated by the current flowing in adjacent stator coils 22 has opposite magnetic poles.

[0059] Permanent magnets 24a, 24b facing each other are arranged on the two rotors 14a, 14b, and the stator coil 22 is arranged therebetween. When the stator bars are arranged tilted (unlike the figure), the magnets are also arranged tilted accordingly. Corresponding gaps 26a, 26b are arranged between each pair of pole shoes / magnets 27 / 24a, 27 / 24b, respectively. In an exemplary motor, after the stator coil 22 is energized, its polarity changes alternately so that the coil is aligned with different pairs of magnets at different times, thereby generating a torque applied between the rotor and the stator.

[0060] The rotors 14a, 14b are typically connected together, for example, by a shaft (not shown), and rotate together about the motor axis 20 relative to the stator 12. In the illustrated embodiment, two adjacent stator bars 16, two pairs of magnets 24a, 24b, and two back plates 32a, 32b (one for each rotor) form a magnetic circuit 30, thereby achieving magnetic flux communication between the backs of each pair of magnets 24a, 24b facing away from the corresponding coil 22. The back plates 32a, 32b can be called back iron and contain magnetic material, usually ferromagnetic material, but not necessarily iron. The magnetic material is not required to be a permanent magnet. The stator coil 16 is enclosed in a housing that defines a chamber for the rotor and the stator, and a cooling medium can be provided in the housing.

[0061] Figure 3 The stator 12a is shown. In the stator 12a, the stator coil is arranged between clamshell-shaped parts 42a, 42b made of plastic material. The two clamshell-shaped parts have an outer cylindrical wall 44, an inner cylindrical wall 46 and an annular end wall 48. Figure 3In the embodiment, the end wall 48 includes an inner cavity 50. When the two clamshell-shaped parts 42a, 42b of the stator 12a are assembled together, the inner cavity 50 accommodates the pole shoes 18a, 18b of the stator bar 16 and is used to fix the stator coil assembly 16, 22, 18a, 18b in place. The stator housing 42a, 42b defines an inner coil space 52 and an outer coil space 54 along the outer side of the coil 22, and there is a space 56 between the coils. The spaces 52, 54, 56 are connected to each other to form a cooling chamber. Although Figure 3 Although not shown, in the assembled state, the stator housings 42a, 42b are provided with ports for a cooling medium such as oil to be pumped into the spaces 52, 54, 56 and circulate around the coils to cool them.

[0062] The coil core may be laminated with an interlayer insulation structure parallel to the desired magnetic flux direction. However, the coil core may also be made of soft iron particles coated with an electrically insulating material and molded into the desired shape (soft magnetic composite (SMC)), wherein the electrically insulating material serves as a matrix to bond the soft iron particles together. The SMC may, for example, comprise iron particles bonded by glass, wherein the glass bonding layer is a thin layer (typically <10 μm) which electrically insulates the iron particles from each other and leaves a certain porosity. The pole shoes 27 may, for example, be molded from SMC by a high temperature and high pressure compaction process. For ease of manufacturing, the pole shoes and stator bars may be made separately and then assembled to each other.

[0063] Figure 4 The rotor of the axial flux permanent magnet machine of the present invention is exploded. The rotor comprises a rotor body 401 on which a group of permanent magnets 402 located on a layer of a metal laminate 403 are arranged. That is, the metal laminate 403 has an internal structure composed of an electrical isolation layer that helps to reduce eddy currents.

[0064] The rotor body 401 may be made of a metal such as steel to provide structural strength to the rotor. The rotor body 401 is also provided with an axial hole 404 running through the center thereof. Figure 4 In the embodiment, the rotor body is provided with a raised portion or outer wall 405a along its outer circumference, and a raised portion or inner wall 405b along its inner circumference, which together form a groove or U-shape on the main surface of the rotor body to accommodate the metal laminate 403 and help it to be fixed in place. The rotor body 401 can be first formed into a shape with a desired tolerance by pressing or machining, and then the metal laminate 402 is arranged thereon.

[0065] The metal stack 403 may, for example, include electrical steel. In addition, other suitable materials are also within the scope of the present invention. Although not shown in the figure, the metal stack 403 is made by winding a metal sheet with a desired width and thickness into a metal roll with a desired diameter. In this way, the resulting stacked structure is a spiral or concentric ring structure around the axial hole 406, and the gap between the layers is determined by the winding tightness. The gap electrically isolates the layers in the metal stack 403 from the adjacent layers to minimize the eddy currents in the metal stack 403. In addition, the gap also magnetically isolates the rotor body 401 from the permanent magnets 402 bonded to the surface of the metal stack 403 to prevent eddy currents from being generated in the rotor body 401.

[0066] exist Figure 4 In the embodiment, the set of permanent magnets 402 is in the form of segmented magnets, and the shape of these segmented magnets enables them to be arranged in a ring shape that matches the shape of the rotor body and the metal laminate. However, other permanent magnet shapes and arrangements are also within the scope of the present invention. For example, a single integrated ring magnet can also be used according to a specific application.

[0067] exist Figure 4 When the rotor is assembled, a brazing compound 407 such as a nickel brazing powder is first deposited on the surface of the rotor body 401 to be brazed with the metal laminate 403, and then the metal laminate 403 is placed (410) on the surface of the rotor body and heated. It should be understood that the heating treatment required for brazing is sufficient to melt the brazing compound 407, but the temperature must not be so high that the base material to be bonded also melts. For example, depending on the brazing compound used, a heating treatment of about 600 to 1200°C, such as a heating treatment of about 1100°C, can be used. Such heating treatment can be completed by a heating furnace, such as a camelback furnace (which can be a conveyor-type camelback furnace), a camelback furnace as a link in a production line, or a vacuum brazing furnace. After heating, the brazing compound cools and solidifies, so that the metal laminate 403 is bonded to the rotor body 401 by brazing.

[0068] It should be understood by those skilled in the art that, as an option, a quenching treatment (for example, in an inert gas such as nitrogen) may be performed, and a tempering treatment may be performed as needed to achieve a desired metal grain structure.

[0069] After the metal laminate 403 is brazed to the rotor body 401 , an adhesive 411 (such as a polymer adhesive) is applied to the exposed surface of the metal laminate 403 and the set of permanent magnets 402 are placed at the desired position thereon to complete the adhesive bonding with the metal laminate 403 .

[0070] Figure 5a and Figure 5bIt is a schematic diagram of a method of bonding the metal laminate 403 to the rotor body after brazing. Figure 5b For along Figure 5a As described above, the brazing compound 407, after heating and cooling, forms a brazed bond that rigidly fixes the layers in the stack in place on the rotor body. Figure 5b The layers of the stacked body shown are an example of the stacked structure, wherein the above-mentioned raised portion or inner and outer walls 405a, 405b of the rotor body 401 form a groove or a U-shaped structure, and the metal sheet is wound into a metal roll in the structure, and each layer in the metal roll is spiral or concentric ring-shaped, and there is a gap between each layer. The layers in the stacked body are aligned in a direction away from the rotor body 401.

[0071] Optionally, for a specific application, after the brazing process is completed, the metal laminate 403 and the rotor body 401 may be flattened or subjected to other plastic deformation processes to achieve a desired flatness, which may be accomplished, for example, in a stamping tool or other tool.

[0072] Figure 6a and Figure 6b 4 is a schematic diagram of an optional step of filling the interlayer gaps of the metal laminate 403 with a filling compound such as a resin after the metal laminate 403 is brazed to the rotor body 401. As mentioned above, a vacuum pressure impregnation (VPI) process may be used. Figure 6a An exemplary VPI tool 600 is shown, which has a closable space 601 in which a conduit 602 is disposed. Through the conduit 602, a filling compound 603 such as a resin can be subjected to a dry-wet vacuum cycle so that the filling compound is impregnated into the interlayer spaces in the metal stack 403.

[0073] Figure 6b For Figure 5b A similar cross-sectional schematic diagram is shown in this figure after the filling compound 603 is applied and the metal stack 403 is impregnated with the filling compound 603. As described above, the filling compound further increases the stacking structure strength and rigidity of the metal stack 403.

[0074] like Figure 6bAs further shown, a layer of filler compound 603 may remain on the upper surface of the metal stack 403. Nevertheless, as described above, due to the greater strength of the brazed bond 407, the risk of damage to the stack caused by physical processing techniques can be reduced. In addition, due to the electrical conductivity of the brazed bond, burrs on the outer surface of the metal stack 403 can be removed by ECM, thereby achieving advantages that can be achieved by ECM as described herein but cannot be achieved by other types of deburring processes. In this way, the exposed surface of the metal stack 403 can be brought to a clean, coplanar, and smooth state before being bonded to a set of permanent magnets by adhesive 411, thereby improving the performance and life of the rotor, increasing the integration of the stack on the object, and promoting electrical isolation between the turns.

[0075] Figure 7 The assembled rotor 700 of the present invention is along the Figure 5a Schematic cross-section of the straight line corresponding to the center line AA, wherein similar elements are represented by similar reference numerals. As described above, the rotor includes a rotor body 401, a set of permanent magnets 402 and a layered metal laminate 403. The metal laminate 403 is bonded to the rotor body 401 by a brazing bond 407, and the set of permanent magnets 402 is bonded to the metal laminate by an adhesive bond 411. The upper surface of the metal laminate 403 (i.e., the surface away from the rotor body 401) can be an electrochemically processed surface.

[0076] As mentioned above, in the assembled state, the rotor can be Figure 3 The stators in the machine are arranged to be axially aligned to form an axial flux permanent magnet machine with a YASA topology.

[0077] Figure 8 The present invention is a flow chart of a method 800 for manufacturing a rotor of an axial flux permanent magnet machine. The machine has: a stator, which includes a group of coils respectively wound on corresponding stator bars and arranged circumferentially at intervals along the axis of the machine; and a rotor, which includes a rotor body, on which a group of permanent magnets are arranged, the group of permanent magnets are located on a layer of a metal laminate and are installed in a manner that can rotate around the axis, wherein the rotor and the stator are separated from each other along the axis to form a gap between the two, and the magnetic flux in the machine is generally in the axial direction in the gap. The method 800 includes: brazing the metal laminate to the rotor body (801); and bonding the group of permanent magnets to the metal laminate (802).

[0078] Fig. 9A flow chart of a method 900 of the present invention for bonding a metal laminate to a rotor body of a rotor. The method 900 includes: applying a brazing compound on a surface of the rotor body (901); placing the metal laminate on the brazing compound on the rotor body (902); and heating the brazing compound to bond the metal laminate to the rotor body (903).

[0079] Fig.10 The flowchart of the metal stack processing method 1000 of the present invention includes: performing electrochemical processing on the surface of the metal stack (1001).

[0080] As used herein, the terms "upper surface," "lower surface," "horizontal direction," and "vertical direction" are used to describe the relative positions of these surfaces and directions relative to one another, and are not intended to limit the present invention to any particular orientation in a coordinate system. The terms "upper," "lower," "horizontal," and "vertical" are intended to facilitate description relative to the drawings herein. Thus, the "upper surface" is the side opposite the lower surface of a component. Similarly, the "inner surface" is the side opposite the outer surface of a component, regardless of the orientation of the component in the coordinate system.

[0081] Undoubtedly, many other effective alternatives will be available to those skilled in the art. It should be understood that the present invention is not limited to the above-described embodiments, but includes modifications that are obvious to those skilled in the art and fall within the scope of the claims.

[0082] For example, although the brazing compound is described above as being applied to the rotor body, the reverse is also within the contemplated scope of the present invention. For example, the brazing compound can also be applied to the metal laminate instead, and the rotor body can be placed on the metal laminate before the brazing process. Similarly, although the adhesive is described above as being applied to the metal laminate before the magnet is placed on the metal laminate, the reverse is also within the contemplated scope of the present invention. For example, the adhesive can also be applied to the magnet instead to achieve the same desired effect.

Claims

1. A method for manufacturing an axial flux permanent magnet machine rotor, characterized in that: The axial flux permanent magnet machine comprises: a stator, the stator comprising a group of coils wound around respective stator bars and arranged circumferentially at intervals around the axis of the axial flux permanent magnet machine; and a rotor, the rotor comprising a rotor body, a group of permanent magnets being arranged on the rotor body, the group of permanent magnets being located on a layer of a metal laminate and being mounted in a manner rotatable around the axis, wherein the rotor and the stator are separated from each other along the axis to form a gap between the rotor and the stator, and the magnetic flux in the axial flux permanent magnet machine is generally in the axial direction in the gap, Wherein, the method comprises: brazing the metal laminate to the rotor body; and The set of permanent magnets is coupled to the metal laminate.

2. The method according to claim 1, characterized in that include: After the metal laminate is brazed to the rotor body and before the bonding of the set of permanent magnets, the surface of the metal laminate is electrochemically machined to deburr the surface.

3. The method according to claim 1 or 2, characterized in that include: A filling compound is applied to the metal stack to fill interlayer gaps of the metal stack.

4. The method according to claim 3, characterized in that Applying the filling compound includes vacuum pressure impregnation with resin.

5. A method according to any one of the preceding claims, characterized in that The brazing comprises: applying a brazing compound to a surface of the rotor body; placing the metal laminate onto the brazing compound on the rotor body; and The brazing compound is heated to bond the metal laminate to the rotor body.

6. The method according to claim 5, characterized in that The heating is carried out by a humpback furnace or a vacuum brazing furnace.

7. The method according to claim 5 or 6, characterized in that include: The rotor body and the bonded metal laminate are quenched and tempered.

8. The method according to claim 7, characterized in that The quenching includes nitrogen quenching.

9. The method according to any one of claims 5 to 8, characterized in that include: After the quenching and the tempering, the rotor body and the metal laminate are planarized.

10. A method according to any one of the preceding claims, characterised in that include: A surface of the metal stack that is flatter than another surface of the metal stack is identified, wherein the brazing is performed on the identified surface.

11. A method according to any one of the preceding claims, characterised in that The permanent magnet is bonded to the metal laminate by an adhesive.

12. An axial flux permanent magnet machine, characterized in that: include: a stator, the stator comprising a group of coils wound around the stator bars and spaced circumferentially around the axis of the axial flux permanent magnet machine; and A rotor having a group of permanent magnets disposed thereon, the group of permanent magnets being located on a layer of the metal laminate and being mounted in a manner rotatable about the axis, wherein the rotor and the stator are separated from each other along the axis to form a gap between the rotor and the stator, and the magnetic flux in the axial flux permanent magnet machine is generally in an axial direction in the gap, Wherein, the rotor comprises: a rotor body; and a brazing connection between the metal laminate and the rotor body.

13. The axial flux permanent magnet machine according to claim 12, characterized in that: The metal laminate includes an electrochemically processed surface.

14. The axial flux permanent magnet machine according to claim 13, characterized in that: A filling compound is included that is disposed in interlayer gaps of the metal stack.

15. The axial flux permanent magnet machine according to claim 14, characterized in that: The filling compound includes a resin.

16. The axial flux permanent magnet machine according to any one of claims 13 to 15, characterized in that: include: an adhesive bond between the metal laminate and the set of permanent magnets; And the metal laminate.

17. A rotor for an axial flux permanent magnet machine, characterized in that: The rotor comprises: a rotor body having a set of permanent magnets disposed thereon on one layer of the metal laminate; and Brazing bonding between the metal laminate and the rotor body.

18. A method for bonding a metal laminate to a rotor body of a rotor, characterized in that: The method comprises: applying a brazing compound to a surface of the rotor body; placing the metal laminate onto the brazing compound on the rotor body; and The brazing compound is heated to bond the metal laminate to the rotor body.

19. The method according to claim 18, characterized in that include: After the metal laminate is brazed to the rotor body, the surface of the metal laminate is electrochemically processed to deburr the surface.

20. The method according to claim 18 or 19, characterized in that include: A filling compound is applied to the metal stack to fill interlayer gaps of the metal stack.

21. A method for processing a metal laminate, characterized in that: The method comprises: The surface of the metal laminate is electrochemically processed.

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