Electric motor components and methods for manufacturing electric motor components for axial-flow motors, and axial-flow motors.

Abstract

To manufacture the stator or rotor of an axial-flow motor, a layered structure is generated by additive manufacturing as follows: - Alternating layered structures (2) with rotationally symmetrical basic shapes are additively generated, wherein different layers (3, 4), namely, a first type of layer (3) composed of filaments containing plastic and soft magnetic metal materials and a second type of layer (4) composed of filaments containing plastic and ceramic, are nested together; - The layered structure (2) generated from the different layers (3, 4) is heated to a first temperature (T1), at which the plastic is removed from the layers (3, 4); - The layered structure (2) is heated further, thereby sintering the soft magnetic metal material of the first type of layer (3) and obtaining an electrically insulating ceramic layer from the second type of layer (4).

Description

Technical Field

[0001] This invention relates to a method for manufacturing a component, particularly a stator, for an axial-flow motor. Furthermore, this invention relates to an electric motor component intended for use in an axial-flow motor, and to an axial-flow motor itself. Background Technology

[0002] Axial-flow motors are known, for example, from EP 1 203 436 B2. A known axial-flow motor comprises an iron-free disc rotor disposed at the machine shaft and two stators disposed beside the rotor. The rotor has permanent magnets embedded in fiber-reinforced plastic. Each stator comprises an annular yoke in which slots are arranged, the slots extending generally radially from the inside to the outside when twisted relative to the permanent magnets of the rotor. The yoke is composed of multiple layers of silicon steel sheets. Multiphase windings, such as three-phase windings, are guided through the slots.

[0003] Another type of motor, configured as an axial-flow motor, is described in DE 10 2015 223 766 A1. In this case, the stator has a sintered support structure. Inserts are joined to the support structure, which at least partially form pole shoes and include a plate stack. The plate stack is constructed of individual plates made of stamped soft iron sheets.

[0004] EP 1 081 386 A2 describes an axial-flow motor as a component of a centrifugal pump. The stator winding of the axial-flow motor includes multiple sub-windings that are positioned differently relative to the rotor of the motor. In this case, the rotor is also fitted with permanent magnets.

[0005] DE 10 2016 119 650 A1 describes a method for manufacturing soft magnetic cores for motors and actuators, wherein the core is constructed from sublayers of different material compositions using an additive manufacturing method. Here, the core can have a ceramic share. The main metallic material composition can have a silicon share of 6.5% or more. Additive manufacturing should be feasible using powdered starting materials. After molding, the powder produced by the additive manufacturing method can be partially blown out. Sintering, also mentioned in DE 10 2016 119 650 A1, should minimize the porosity of the workpiece, i.e., the components of the motor.

[0006] Another method for manufacturing components for an electric motor is disclosed in DE 10 2017 220 735 A1. In this case, the individual plates of the stator should be manufactured by a three-dimensional generative production method, such that no compressive or tensile stress occurs in the bending areas of the plates. Laser sintering is mentioned, for example, as a generative production method. Insulating films or insulating varnishes are proposed as the insulating material between the plates. Generally, the machine according to DE 10 2017 220 735 A1 is a cross-flow machine.

[0007] DE 10 2017 222 635 A1 describes a stator of an electric motor with a cooling system. Here, it is proposed to manufacture the cooling channel walls using an additive manufacturing method. This eliminates the need for additional sealing of the cooling channel walls relative to the stator plate.

[0008] A rotating body for a magnetoresistive machine is known from EP 3 255 758 A1, said rotating body being manufactured at least partially by additive manufacturing. As the initial material for additive manufacturing, intangible materials, such as liquids or powders, or shape-neutral materials, such as strips or wires, may be used. The resulting rotating body, manufactured using additive methods, alternately has conductor layers and insulating layers along the axial direction. Intermediate insulating tabs should also be additively manufactured.

[0009] WO 2019 / 022973 A1 focuses on additive manufacturing of vehicle components. Here, the ADAM (Atomic Diffusion Additive Manufacturing) method is proposed. A typical ADAM method uses initial materials comprising metal and plastic, wherein the plastic is melted away. The remaining metal is sealed by sintering.

[0010] Methods and apparatus for the generative production of fiber reinforcement are described, for example, in documents WO 2017 / 123726 A1 and EP 3444 102 A1.

[0011] The filaments described in US 10,016,942B2 are intended to be virtually pore-free and comprise a polymer that surrounds a multi-strand core.

[0012] WO 2018 / 102739 A1 describes the feasibility of sintering production using a sealed connection platform.

[0013] US 2018 / 0236546 A1 proposes sintering at two temperature levels in conjunction with additive manufacturing, wherein the first temperature level is 500 to 700 degrees Celsius and the second temperature level is 1000 to 1200 degrees Celsius.

[0014] A 3D printing method that embeds parts into 3D printing material is disclosed in WO 2016 / 146374 A1. The embedded parts differ in their thermal or magnetic properties from the surrounding 3D printing material.

[0015] The feasibility of fabricating filaments for coatings in extrusion-based 3D printing is described in WO 2014 / 0172148 A1. It is proposed here that the filaments be coated using a separate method outside of the printer.

[0016] DE 10 2018 003 864 A1 discloses a method for printing and sintering molded articles produced from metal and ceramic-filled filaments.

[0017] Regardless of additive manufacturing methods, electrical steel strips are typically used to manufacture components for electric motors. The varnished electrical steel strips described in DE 10 2018209 553 A1 can have a total alloy share of silicon and aluminum equal to or greater than 1%, 2%, 3%, or 4%. Possible silicon share values ​​mentioned are 0.8%, 1.5%, 2%, and 3%.

[0018] The electrical steel strip described in DE 10 2018 201 622 A1 has a silicon content of 2.3 to 2.7% and an aluminum content of 0.3 to 0.8%, respectively, given as a weight percentage. Summary of the Invention

[0019] The present invention is based on the following objective, particularly in terms of production technology, to improve the electric motor configured as an axial flow motor compared to the prior art.

[0020] The objective according to the invention is achieved by a method for manufacturing an electric motor component, i.e., a stator or rotor, according to claim 1. Similarly, the objective is achieved by an electric motor component having the features of claim 9, intended for use in an axial-flow motor. The objective is further achieved by an axial-flow motor according to claim 11. The designs and advantages of the invention described below in conjunction with the electric motor component and the axial-flow motor are also applicable to the manufacturing method and vice versa.

[0021] This invention is based on the consideration that the active components of the motor, namely the rotor or stator, should be optimized for alternating field losses in axial flow machines as they are in radial flow machines, in order to achieve the highest possible efficiency of the motor.

[0022] Compared to radial flow machines, axial flow machines present more complex requirements, involving the optimized setup and separation of layers composed of conductive materials with respect to minimizing alternating field losses. This complexity is expressed, for example, in DE 10 2015 223766 A1, as multiple individual plate stacks connected to the stator's support structure. Another known approach involves the use of SMC (soft magnetic component) materials, as described, for example, in WO 2016 / 066714 A2. SMC comprises metal particles that are electrically insulated from each other.

[0023] In contrast to known methods, the method for manufacturing motor components, particularly stators, of axial-flow motors according to this application comprises the following steps:

[0024] -Additively producing alternating layered structures with rotationally symmetric basic shapes, wherein different layers, namely a first type of layer composed of filaments containing plastic and soft magnetic metal materials and a second type of layer composed of filaments containing plastic and ceramic, are nested within each other.

[0025] - The layered structure, composed of different layers, is heated to a first temperature, at which point the plastic is removed from the layers.

[0026] - Continue heating the layer construction, thereby sintering the soft magnetic metal material of the first type of layer and obtaining an electrically insulating ceramic layer from the second type of layer.

[0027] According to one possible design scheme, the layers are constructed in a spiral shape.

[0028] This allows for the creation of multi-layered structures having only a single, continuously spiraling volume region filled with a first type of material, namely a soft magnetic and conductive metallic material. The individual windings of this spiral volume region are insulated from each other by an overall spiral volume region containing a second type of material. The spiral layered structure can be produced using an additive manufacturing facility, in which the workpiece, i.e., the resulting layered structure, rotates relative to a device consisting of multiple printheads. Here, the first type of layer is constructed by a first printhead, while the second type of layer is constructed by another printhead. The different printheads can operate completely or largely simultaneously. Overall, the layered structure can be constructed from the inside out or from the outside in.

[0029] According to an alternative design, the layers are nested within each other as concentric rings. Overall, there are, for example, at least four, and especially at least eight, separately annular, i.e., cylindrical layers. Significantly higher numbers of layers, such as 30 or more, can also be produced using this construction.

[0030] Regardless of the spiral structure or individual rings described in the layer description, the first type of layer is used as a layer for conducting magnetic flux in the manufactured motor components, and it is separated from each other by the second type of layer, namely the insulating layer. The different filaments used to construct the layers are generally referred to as plastic / metal filaments or plastic / ceramic filaments, wherein the filaments, simplified as "plastic," optionally include other components. In any case, the filaments used to construct the layer assembly have a linear configuration, wherein the diameter of the plastic / metal filaments can differ from the diameter of the plastic / ceramic filaments.

[0031] After the complete construction of the device formed of different layers, the heat treatment of the entire layered device is carried out under conditions that maintain a defined temperature profile, wherein different variations of the method are feasible. In any case, at least most of the plastic portion is removed from all layers—not necessarily simultaneously—followed by a temperature increase either directly or at any subsequent moment, so that the sintering of the metal of the first type of layer begins and ceramics are produced from the second layer in the same sintering process.

[0032] Overall, the filament-based production of motor components, particularly stators or rotors, results in a layered structure in which conductive and softly magnetically conductive layers, i.e., first-type layers, are electrically insulated from each other and mechanically fixedly connected by ceramic layers. By using filaments as a precursor product, significantly higher geometric precision can be achieved compared to powdered initial materials. The multi-stage heating layer apparatus further ensures that the workpiece, i.e., the motor component to be manufactured, is stabilized before sintering, and that undesirable effects, such as those caused by diffusion, are minimized. The thickness of each layer in the finished product, i.e., the component suitable for insertion into an axial-flow motor, can be set as needed and, for example, not greater than 0.35 mm. Layer thicknesses of softly magnetic metal layers in the range of 0.2 to 0.35 mm and ceramic layers in the range of 0.01 to 0.2 mm have proven suitable.

[0033] According to a feasible method, after reaching a first temperature level, the workpiece is placed at an intermediate temperature level, which is closer to the first temperature level than the second temperature level, i.e., the temperature level selected for sintering. In other words, the first temperature level is divided into two levels that are close to each other but clearly distinguishable, and are set sequentially. The separate temperature levels used before sintering have the effect that only one layer type changes initially, and then the other layer type changes subsequently. For example, the plastic portion of all layers of the first type is first removed, where the plastic portion of the second type of layers that is not damaged at this moment simultaneously ensures that the metal components of all layers of the first type remain completely separated from each other. When the temperature is then moderately increased to the intermediate level, virtually no further changes occur in the layers of the first type. More precisely, during the processing stage, the plastic is removed from the layers of the second type, where, not disadvantageously, some of the plastic reaches into the layers of the first type.

[0034] After the previous processing, namely the removal of plastic at a constant temperature level or separate levels, subsequent sintering can be performed. Sintering can also be performed at a uniform temperature level or using different, sequentially set temperatures. For example, a temperature level is first selected at which the sintering of the essentially metallic layer, i.e., the first type of layer, is completed. Here, a reduction in the overall volume of the component can occur. Because sintering has not yet occurred in the ceramic component, i.e., within the second type of layer, during the processing stage, the ceramic material matches the dimensional changes of the metal layer. Subsequently, a temperature level, referred to as the high-temperature level, is set at which the sintering process in the second type of layer is completed, i.e., the final ceramic layer is produced from the layer. The boundary between the metal layer and the ceramic layer is ultimately structured such that, on the one hand, a fixed interlocking is achieved between the layers, and on the other hand, excessive fluctuations in layer thickness occur.

[0035] Compared to components manufactured from electrical boards, the components of the axial-flow motor according to this application have a particularly significant advantage: a much greater degree of freedom regarding the composition of the layers. In a preferred design, the total mass content of silicon and aluminum in the metal layers is greater than 5% by weight. The soft magnetic metal material is formed, in particular, by an iron alloy containing greater than 6.5% by weight of silicon and aluminum in the range of 1 to 5% by weight. Particularly preferably, the soft magnetic metal material is formed by an iron alloy containing 6.5 to 10% by weight of silicon and aluminum in the range of 1 to 5% by weight.

[0036] The axial-flow motor according to the invention includes at least one motor component in the form of a rotor or stator according to the invention. In particular, the axial-flow motor is an asynchronous motor.

[0037] During generative production, contours, such as holes, can be introduced into the layer structure when constructing the layers. Optionally, generative production is followed by a final machining step, which may include heat treatment and / or mechanical treatment, such as grinding. Attached Figure Description

[0038] Several embodiments of the present invention are described in detail below with reference to the accompanying drawings. Wherein are shown:

[0039] Figure 1 A simplified cross-sectional view of a first embodiment of the stator of an axial flow motor is shown.

[0040] Figure 2 Showing the manufacturing process according to Figure 1 A symbolic view of the stator device.

[0041] Figure 3 The second embodiment of the stator of the axial flow motor is shown to be similar to... Figure 1 The view,

[0042] Figure 4 A flowchart illustrating the basic features of a method for manufacturing the stator of an axial-flow motor.

[0043] Figures 5 to 7 Different variations of temperature control are shown in the manufacturing of the stator of an axial flow motor. Detailed Implementation

[0044] Unless otherwise stated, the following description applies to all embodiments. Corresponding or substantially identical parts or parameters are denoted by the same reference numerals throughout the figures.

[0045] The motor component, generally represented by 1, is the stator of an axial-flow motor (not shown further). The motor component 1 has a layered structure 2, formed by at least one first-type layer 3 and at least one second-type layer 4. Within the manufactured motor component 1, the first-type layer 3 is a metal layer made of a soft magnetic metallic material, and the second-type layer 4 is a ceramic layer. Figures 1 to 3 The visible tubular or disc-shaped load-bearing member 5 is surrounded by the layer structure 2 and is installed therein as part of the stator 1 when the motor is installed. In an alternative method of control, the load-bearing member 5 is functional only when the layer structure 2 is produced and is removed from it again after the layer structure 2 is manufactured.

[0046] In manufacturing layer 2, the principle of the already known ADAM method is utilized. Based on... Figure 1 In the embodiment, layers 3 and 4 are spirally constructed, and their arrangement is based on... Figure 2 One embodiment has the form of concentrically nested rings.

[0047] In order to illustrate what can be used to generate the basis Figure 1 The method of layer construction 2 of stator 1 is referred to Figure 2 Accordingly, the metal support member 5 is positioned within a device comprising two printheads 8 and 9 of the additive manufacturing facility. Additive manufacturing can be performed by rotating the support member 5 about its central axis MA, or by rotating the device consisting of the two printheads 8 and 9 about the support member 5, i.e., by guiding it along the circumference of the support member 5. Depending on the design of the printheads 8 and 9 and the dimensions of the support member 5, axial relative movement between the printheads 8 and 9 on one side and the support member 5 on the other side—about the central axis MA—can also be proposed. Figure 1 The hole 7 shown in the figure is generated directly during the additive manufacturing process of layer 2.

[0048] according to Figure 4 The flowchart illustrates the manufacturing process. Figure 1 Electric motor component 1 and manufacturing method Figure 3The motor component 1. In both cases, in the first method step S1, a spiral or cylindrical layer structure 2 is first generated by 3D printing, i.e., a blank is manufactured.

[0049] Subsequently, heat treatment of layer structure 2 is performed in step S2, which will be discussed in more detail. The furnace is in... Figure 4 The symbol is represented by 6. After the heat treatment is completed, a reprocessing of layer structure 2 is performed in step S3, which may include surface treatment. Step S4 marks the end of the method.

[0050] exist Figures 5 to 7 Different variations of temperature control in step S2 of the sketching method. All three variations share the common feature that the temperature T of the workpiece, i.e., layer structure 2, is first raised to a first temperature level T1, at which the plastic components are removed. The significantly higher temperature level T2 achieved in all variations triggers the sintering process.

[0051] In the simplest, Figure 5 The variant illustrated in the diagram maintains a temperature level T1 during the time period t1 to t4. In this case, a constant temperature level T2 is maintained during the time period t5 to t8.

[0052] According to Figure 6 In this variation of the method, the lower temperature levels are separated: the first temperature level T1 is maintained only during the time period t1 to t2. The intermediate temperature level T2 is significantly closer to the first temperature level T1 than the second temperature level T2. 11 Set during time periods t3 to t4. Overall, during time periods t1 to t4, the plastic components are removed from the two layer types 3 and 4, where temperature levels T1 and T... 11 The setup is configured such that the plastic components are sequentially removed from the different layer types 3 and 4. This involves heat treatment at a second temperature level T2, based on... Figure 5 Variations and based on Figure 6 There is no difference between the variant forms.

[0053] according to Figure 7 Method variations regarding temperature levels T1, T 11 The processing and basis Figure 6 The variant forms are consistent. The difference arises only at higher temperatures: after the second temperature level T2 remains constant from t5 to t6, the temperature T is set at an excessively high temperature level T during the time period t7 to t8. 22 The higher temperature levels ensure that the sintering process is carried out sequentially in layer types 3 and 4 in a defined manner.

[0054] With any basis Figures 5 to 7The described method, in its variant form, can achieve a thickness of less than 0.35 mm for layers 3 and 4.

[0055] Explanation of reference numerals in the attached figures

[0056] 1. Electric motor components, stator

[0057] 2-layer structure

[0058] 3. Type 1 layer, metal layer

[0059] 4. Second type of layer, ceramic layer

[0060] 5. Load-bearing components

[0061] 6 furnaces

[0062] 7 holes

[0063] 8. Printheads for manufacturing first-type layers

[0064] 9. Printheads for manufacturing second-type layers

[0065] MA midline

[0066] S1……S4 Method Steps

[0067] t time

[0068] Time intervals t0 to t9

[0069] T temperature

[0070] T1 First Temperature Level

[0071] T 11 intermediate temperature level

[0072] T2 Second Temperature Level

[0073] T 22 Excessive temperature level

Claims

1. A method for manufacturing an electric motor component (1) for an axial-flow motor, comprising the following steps: -Additively producing alternating layer structures (2) with rotationally symmetric basic shapes, wherein different layers (3, 4), namely, a first type of layer (3) composed of filaments containing plastic and soft magnetic metal materials and a second type of layer (4) composed of filaments containing plastic and ceramic, are nested together. in, The layers (3, 4) are nested together as concentric rings, or the layers (3, 4) are constructed in a spiral shape. The layers (3, 4) are constructed during relative rotation between the workpiece, i.e. the generated layer structure (2), and the device consisting of multiple printheads (8, 9); - The layer structure (2) formed by different layers (3, 4) is heated to a first temperature (T1), at which the plastic is removed from the layers (3, 4). - Continue heating the layer structure (2) to sinter the soft magnetic metal material of the first type layer (3) and obtain an electrically insulating ceramic layer from the second type layer (4).

2. The method according to claim 1, Its features are, At two successively set temperature levels (T2, T... 22 The layers (3, 4) are sintered.

3. The method according to claim 1, Its features are, The layers (3, 4) are constructed from the inside out.

4. The method according to claim 1, Its features are, The layers (3, 4) are constructed from the outside in.

5. The method according to any one of claims 1 to 4, Its features are, The soft magnetic metallic material is formed by an iron alloy containing more than 6.5% by weight of silicon and aluminum in the range of 1 to 5% by weight.

6. The method according to claim 5, Its features are, The soft magnetic metallic material is formed by an iron alloy containing 6.5 to 10% by weight of silicon and 1 to 5% by weight of aluminum.

7. An electric motor component of an axial-flow motor having a layered structure (2) additively produced according to any one of claims 1 to 6, said layered structure being composed of a soft magnetic metal layer and a ceramic layer (3, 4).

8. The motor component according to claim 7, Its features are, The thickness of each layer (3, 4) is no more than 0.35 mm.

9. An axial-flow motor comprising at least one motor component (1) in the form of a rotor or stator according to any one of claims 7 and 8.

10. The axial flow motor according to claim 9, Its features are, It is an asynchronous motor.

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