Process for the production of electrical energy converters and energy converters produced thereby

Abstract

Method for producing an electrical energy converter, in which the production of at least one electrical conductor / conductor system and an electrical coil with coil carrier and a rotor (7) and / or stator (16) is carried out using a three-dimensional screen printing process using different screens and / or suspensions in individual layers formed one above the other, where after formation of a respective layer, a fixation, preferably by means of drying, and after formation of the three-dimensional shape, a sintering of the element, which until then was present as a green body, is carried out and in the process Electrically and / or magnetically non-conductive parts are manufactured using ceramic powder directly next to electrically and / or magnetically conductive areas as insulators.

Description

[0001] The invention relates to a method for producing electrical energy converters and energy converters produced thereby. These primarily involve electric motors and generators. However, transformers or magnetic bearings should also be capable of being stressed and manufactured using the method.

[0002] Thermal resistance is a problem for such energy converters, particularly due to the materials commonly used (resins, other polymers and fabrics), so use at temperatures above 200 °C and generally already above 150 °C is not easily possible.

[0003] In addition, the high heat transfer resistance of the materials commonly used is a disadvantage.

[0004] The thermal problems cannot be taken into account, especially in small energy converters, by targeted cooling with fluids (liquids and gases), or can only be taken into account with great effort and cost.

[0005] Since some components, particularly within the magnetic circuit, are assembled from multiple parts, as is the case with laminated parts, their mechanical stability is limited, which is particularly detrimental to rotating or otherwise moving parts. Axial field guidance is not possible on laminated parts such as a rotor.

[0006] A local adaptation of physical properties, such as density, cannot be easily achieved via the respective volume of a component of an energy converter.

[0007] With conventional energy converters, the electrical connection or external electrical contact to an electrical power grid also poses problems. Particularly with small-sized energy converters, considerable effort, including manual labor, is required.

[0008] The desired miniaturization is also limited by the assembly effort and the existing assembly options, which leads to problems particularly in the area of ​​electrical coils, pole and slot shapes and taking into account the required air gap between a rotor and a stator.

[0009] Conventional energy converters are currently manufactured from many individual parts and components, which significantly increases manufacturing and assembly costs. Fully automated production is therefore also only possible, if at all, with considerable effort.

[0010] Many of the individual required parts require post-processing, such as forming, machining, separating, surface treatment, or a protective surface coating. However, such processing can also impair properties, particularly magnetic properties.

[0011] Manufacturing and assembly are therefore very susceptible to errors, resulting in a correspondingly high scrap rate or the need for complex reworking.

[0012] For electric motors and generators, electrical laminations (sheet metal with an electrically insulating coating) must be shaped, which can be achieved through cutting processes or machining. The formed electrical laminations must then be stacked and positioned relative to each other. The key here is to minimize the offset between individual laminations while achieving a strong connection.

[0013] When manufacturing the required electrical coils, copper wire is typically formed into multiple coil windings. This is a particularly critical and complex manufacturing step. Consideration must be given to the respective winding properties and optimal design of the magnetic circuit, as well as the shape of the electrical laminations.

[0014] For example, US 5,822,839 A discloses a method for manufacturing a micromotor from ceramic substrates. US 2011 / 0 148 554 A1 describes the production of a multi-axis actuator, with individual elements being manufactured using an LTCC process. US 2006 / 0 066 159 A1 relates to a method in which a rotating electrical machine is formed from compacted and sintered material with fluid feedthroughs.

[0015] US 2007 / 0 007 827 A1 discloses an electromagnetic device for converting mechanical vibrations into electrical energy and its production by means of thick-film processes.

[0016] Another manufacturing process is the formation of electrical conductors by applying electrically conductive material to a substrate and the locally defined oxidation of the material using a high-energy beam (US 5 575 932 A).

[0017] DE 195 22 287 C2 describes a method for producing planar micromotors using photosensitive structuring materials.

[0018] US 2004 / 0 202 797 A1 describes the production of electromagnetic units by means of cold gas spraying.

[0019] The disclosure of US 2010 / 0 201 473 A1 relates to a component with multiple coils and a manufacturing method therefor.

[0020] DE 10 2010 013 651 A1 as the closest prior art relates to a method and a device for the three-dimensional magnetic shaping of a motor core.

[0021] JP H11-266 556 A relates to the manufacture of stators of a motor and JP H05-336 712 A relates to the manufacture of coils for electric motors, each by means of screen printing.

[0022] US 2009 / 0 072 654 A1 discloses an insulator for an electrical machine.

[0023] The disclosure of JP 3 891 545 B2 also relates to the manufacture of electric motors.

[0024] The object of the invention is therefore to provide electrical energy converters that can be manufactured with high precision and with reduced effort. This applies particularly to small-format energy converters.

[0025] According to the invention, this object is achieved by a method for producing an energy converter having the features of claim 1 and an energy converter having the features of claim 2. Advantageous embodiments and further developments of the invention can be realized with features specified in subordinate claims.

[0026] An electrical energy converter manufactured according to the invention comprises a stator and a rotor, electrical conductors, an electrical conductor system, and / or electrical coils. Electrical coils are present in all energy converters covered by the invention, including transformers and linear motors. Electrical coils can also be present on a coil carrier. Electrical conductors or electrical conductor systems can be present or designed in a wide variety of forms, although electrical conductors can, of course, also be used to form electrical coils.

[0027] The rotor and / or the stator and / or at least one electrical coil with a coil carrier is manufactured as a three-dimensional monolithic element and consists of sintered electrically conductive, magnetically conductive, magnetically non-conductive, electrically non-conductive, magnetic, and / or magnetizable materials. Individual parts of the rotor and / or stator, as well as the electrical coil and the coil carrier, can be made of different materials.

[0028] In this context, a monolithic element should be truly three-dimensional, and should not include, for example, printed or otherwise manufactured flat structures, such as printed electrical conductors. Accordingly, structures / structural elements should be present that protrude several millimeters, preferably at least 3 mm, above a surface in an axial direction.

[0029] An energy converter manufactured according to the invention should be a composite component produced additively from ceramic and / or metallic materials. These materials can be used to design and manufacture different regions and elements that are then already present in the composite component, without the need for subsequent joining or assembly. The ceramic or metallic materials selected in each case allow for the desired local properties of the energy converter, such as electrical insulation, electrical or thermal conductivity, as well as magnetic or electromagnetic properties.

[0030] A monolithic element is composed of several sections that form distinct elements and are not connected to each other by any additional fasteners that would require assembly. The connection is achieved exclusively through a material bond in combination with positive and frictional locking, solely through the manufacturing process.

[0031] The production of a rotor, a stator, or an electrical coil with a coil carrier is carried out using three-dimensional screen printing. Different screens and / or suspensions are used in individual layers, one above the other. This involves a successive layer-by-layer construction of the three-dimensional shape of the respective monolithic element. Screens can be used for the layers, with which the contour is formed layer by layer and areas with different suspensions are formed in a single plane. The suspensions are produced with the desired powdered materials, which are later sintered together to form the individual elements with the desired electrical and magnetic properties.According to the invention, electrically and / or magnetically non-conductive parts are produced using ceramic powder directly next to electrically and / or magnetically conductive areas, as insulators.

[0032] Suspensions used in the invention can also contain powder mixtures of at least two materials. Furthermore, it is also possible to use metal powder alloys in suspensions. In this case, the sintering temperature of the metal alloy can advantageously be adapted to the sintering temperature of other powders to be sintered during production with different properties, which are used for other elements or components of an energy converter. Adaptation to the thermal expansion coefficients of such other materials is also possible in this way.

[0033] Another parameter that can be considered when using powdered materials for suspensions is the average particle size and, if applicable, the particle size distribution, which influence sintering behavior. For many materials, sintering activity is often higher with smaller particle sizes than with larger ones.

[0034] Iron, copper, silver, nickel, aluminum, gold or their alloys can be used preferably for electrically conductive areas, elements or components of energy converters.

[0035] Different ceramic powders, such as aluminum oxide, zirconium oxide, silicon carbide, silicon nitride, boron nitride or boron carbide, can be used as electrically non-conductive materials.

[0036] Suitable magnetic or magnetizable materials include neodymium, iron, boron, samarium, nickel and their alloys.

[0037] They can also be used to create magnets on an energy converter.

[0038] During the manufacturing process, after each layer has been formed, it is fixed, preferably by drying. This can be achieved by simple irradiation with electromagnetic radiation (e.g., IR radiation). After the three-dimensional shape has been formed, the rotor, stator, or electrical coil with coil carrier, which was previously a green body, is sintered. The respective element or component of the energy converter is then fully manufactured as a monolithic three-dimensional element. Only final assembly is then required.

[0039] Cavities or openings for the flow of a temperature control fluid can be formed directly on a rotor and / or stator and / or a coil carrier. These cavities or openings can also be created directly using the screen printing process, eliminating the need for any corresponding post-processing. The manufacturing method according to the invention makes it possible to use such elements in small-format energy converters for the first time, as they were previously impossible to manufacture or could only be manufactured with great effort. This form also allows cooling of the energy converters, as cooling channels are available.

[0040] Electrical conductors, electrical connection contacts, electrical conductor tracks, permanent magnets, electrical insulators, magnetic insulators, magnetic conductors, fastening elements, bearing seats, and / or commutators can be directly and immediately formed on a rotor and / or stator. Sensors can also be integrated, which can also be formed using screen printing. Sensors can, for example, measure electrical parameters or even temperature.

[0041] All of these individual elements can be positioned virtually anywhere within the three-dimensional structure. This allows electrical connections to be routed to the outside in such a way that, when inserted into a housing, electrical contact to the outside can be achieved without any additional work.

[0042] Electrical and / or magnetic conductors can be enclosed by an electrically non-conductive material, insulating them from the surrounding material. These materials can also be mixed with one another, alone or in addition. The electrical and magnetic properties can be modified by the mixing ratio. The invention makes it possible to form electrical conductors, such as the windings of electrical coils, when printing the individual layers and to form electrical insulators directly next to and above them by printing suspensions formed from electrically non-conductive materials. The electrical conductors can thus be positioned very precisely, reproducibly, and tightly packed, which is advantageous for the achievable overall efficiency and power density.

[0043] In the area of ​​an opening in a cavity or perforation for the flow of a temperature control fluid, an element can be provided that compresses the fluid toward the cavity or perforation or in the opposite direction. This element can preferably be provided with at least one blade-shaped element. For example, a blade wheel can be formed directly on a rotor without the need for additional mounting on a shaft or hub. This allows air or a cooling fluid to be guided through the respective area for cooling.

[0044] Particularly considering the thermal aspect, it is advantageous that the rotor and / or stator, and / or an electrical coil with a coil carrier, manufactured as a monolith from several different materials, cannot contain any organic chemical components. This increases the temperature at which the respective energy converter can operate safely.

[0045] Porous areas may be present on a rotor and / or stator and / or coil carrier. This allows the mass in these areas to be reduced. In rotors, this results in lower centrifugal forces, which has a positive effect on bearing requirements and dynamic operating behavior and is particularly advantageous when operating at very high speeds.

[0046] The magnetic flux and / or the electric current can be guided in a targeted three-dimensional manner due to isotropic and / or anisotropic material properties and / or introduced material combinations. By influencing the material structure during the pressure and heat treatment process, e.g. the grain orientation of ferromagnetic materials, the directional dependence of various material properties can be adjusted. Furthermore, these properties can be influenced by the local addition of additives to the material, with varying degrees of intensity. Furthermore, materials with different properties can be layered or enclosed in adjacent areas, for example. In this way, the preferred direction of the magnetic flux and / or electric current can be determined, for example, by a path of lower resistance.

[0047] These variants also allow for adjustment of the thermal properties to precisely control heat transfer. Transitions at the limits of material combinations also play a role. For example, if the joint gap of conventional manufacturing processes is eliminated when inserting the stator into the motor housing, the thermal resistance between the stator and the environment is significantly reduced. The invention allows the limitations of conventional machine designs to be overcome.

[0048] In addition, the thermal conductivity can be locally adjusted in three-dimensional form by means of isotropic and / or anisotropic material properties and / or introduced material combinations and / or their characteristics in the area of ​​the material transitions / boundaries.

[0049] Conductors in one or more coils can have a geometry that differs from the classic one, preferably a polygonal conductor geometry.

[0050] It is also possible to produce circuit board-like winding heads by screen printing, for example, with ceramic insulation / base, which also serve, but not exclusively, as supports for power electronics and / or electronic and / or sensor components. This can be designed similarly to a conventional circuit board, so that electrical conductors and other electrical elements, such as capacitors, inductive elements, or sensors, are manufactured at the same time, thus avoiding or at least reducing subsequent assembly effort. Electrical elements or sensors can be manufactured simultaneously, so that subsequent accessibility for assembly does not need to be considered during their arrangement.

[0051] Furthermore, a carrier or carrier plate can contain cavities that can be used to dissipate thermal energy from the winding or electronics. A carrier, which can also be designed in the form of a disk, can form a receptacle for a bearing, in particular a motor bearing.

[0052] The invention allows for the production of very small energy converters, preferably in large quantities. The screens used can be designed in such a way that when printing a respective layer, several elements, which may be identical or different, are printed simultaneously, thus reducing the time required. Very complex geometries can be formed. For example, undercuts, as well as cavities or channels with alternating directions, can be created. Furthermore, it is possible to enlarge at least surface areas or the specific surface area in certain regions, which can lead to improved heat dissipation and thus improved cooling.

[0053] High fill factors can be achieved in the magnetic circuit of energy converters. The potential use of materials that can be processed in the invention allows for increased thermal resistance and conductivity to be advantageously utilized. This is particularly possible due to the potential elimination of organic substances such as polymers.

[0054] In particular, materials with increased electrical conductivity can be used for the windings of electrical coils, which can also be positioned very close to one another and yet still be sufficiently electrically insulated from one another.

[0055] The individual elements and components of energy converters can be manufactured very precisely and at least close to their final shape, so that post-processing is not necessary, or the effort required can at least be reduced.

[0056] Very large aspect ratios > 500 can be accommodated during manufacturing, allowing for very small spacing and, for example, gap widths. This allows coil windings to have different cross-sectional shapes and dimensions as required. For example, they can have rectangular cross-sections with different widths and heights, allowing them to be optimized to suit the specific design. Individual elements can be formed in the submillimeter range, which can improve heat dissipation, especially in small-sized energy converters.

[0057] The achievable aspect ratio can also be used for optimization of the magnetic flux and corresponding magnetic losses.

[0058] Energy converters manufactured according to the invention can be provided with a large number of poles, which is also possible for small electric motors.

[0059] Due to the manufacturing method of the energy converters, there are no negative effects on the materials caused by the processing required for conventional energy converters. Magnetization effort can be reduced, and pre-calculation of the parameters of an energy converter manufactured according to the invention can be improved. Furthermore, hysteresis losses, for example, can be reduced.

[0060] In addition to large quantities, custom-made products can also be manufactured as prototypes or for special applications. High levels of efficiency and utilization factors (e.g., power density) can still be achieved.

[0061] Since the materials used in the invention can also be resistant to environmental influences, it can be used under many conditions that are normally corrosive, for example, or even in a vacuum.

[0062] For energy converters manufactured according to the invention, such as electric motors, the maximum operating temperature can be significantly higher, ranging from 700 °C to 800 °C. The Curie temperature of iron can be considered as the theoretical maximum temperature.

[0063] The invention also makes it possible to produce a stator with a housing as a three-dimensional monolithic element. The invention will be explained in more detail below using an example.

[0064] Showing: Fig. 1 a rotor and a stator for an electric motor; Fig. 2 a schematic representation of an electric motor; Fig. 3 a schematic representation of a stator; Fig. 4 a schematic representation of a part of an energy converter, with magnetically conductive areas that are insulated from each other with electrically non-conductive layers and Fig. 5a and 5b Examples of conductor geometries of coils.

[0065] The Fig. The stator 16 and the rotor 7 shown in Figure 1 are successively built up with individual layers produced one above the other by screen printing, in which suspensions containing different powdered materials are applied through screens with a doctor blade.

[0066] Several fastening elements 1 can be formed directly on the stator 16. In this case, these are openings through which a screw connection to a housing (not shown) can be established. Openings 3, which form cooling channels, are formed on the stator 16, which is made of FeSi after sintering. Furthermore, a winding chamber 6 is defined by a pole piece 5.

[0067] On the radially outer periphery, structured elements 2 have been formed which increase the surface area and can provide improved heat dissipation.

[0068] Rotor 7 was also formed by screen printing with a suspension consisting of a magnetically conductive powder (40 to 90 mass%) with an average particle size in the range of 1 µm to 50 µm and a liquid organic binder. Rotor 7 also features perforations 4 that form cooling channels.

[0069] In Fig. Figure 2 schematically shows the structure of an example of an energy converter manufactured according to the invention in the form of an electric motor. The stator 16 features stator teeth 10 made of a material with high magnetic conductivity, such as FeCo, and stator backs / yokes 9.

[0070] A porous region has been formed on rotor 7 in the area around the rotation axis. A suspension consisting of powdered FeSi with an average particle size of 10 µm to 15 µm and pyrrolidone as a binder was used. The pores can be formed during heat treatment by removing organic particles contained in the suspension through pyrolysis, and then creating the corresponding pores after sintering. This porous region allows the inherent mass of rotor 7 to be reduced, which leads to a reduction in inertia.

[0071] In this example, permanent magnets 11 were also screen-printed on rotor 7. A suspension consisting of Nd, Fe, B, or Co was used for this purpose. The respective proportions of the powders can be selected depending on the desired field strength of the permanent magnet. The permanent magnets are then made of NdFeB or SmCo. They are magnetized after sintering.

[0072] The Fig. Figure 3 shows a schematic of a stator 16 of an electric motor. Electrical conductors 14, which form electrical coils, are screen-printed from copper. The individual windings formed by the electrical conductors 14 are enclosed by zirconium oxide, an electrically non-conductive ceramic material, so that they are electrically insulated from one another.

[0073] The Fig.Figure 4 shows a schematic representation of part of an energy converter, with magnetically conductive regions insulated from each other by electrically non-conductive layers. In the example shown, several layers have been formed one above the other by screen printing. In this case, these are layers 17 made of magnetically conductive material and layers 18 made of electrically non-conductive material.

[0074] For screen printing, for example, a suspension containing metallic powders made of an iron-silicon alloy with an average particle size of approximately 10 µm can be used. The powder content in the water-based polyvinyl alcohol suspension is approximately 80 percent by mass. The suspension is screen-printed layer by layer onto a substrate, with an average layer thickness of 20 µm. The screen or multiple screens can be used to give each layer a desired two-dimensional contour. The three-dimensional shape can then be created by using different screens.

[0075] After printing, the produced green part is debound in a hydrogen atmosphere at 600°C, i.e., the organic components are removed. It is then sintered at a temperature of 1250°C.

[0076] Two different suspensions can be used to produce electrically insulated layers. One suspension is mixed with ceramic powder, the other with metallic powder. The materials should be matched in terms of their thermal expansion coefficients to prevent delamination stresses during subsequent sintering. Likewise, the particle sizes of the powders used should be matched to ensure equal sintering temperatures.

[0077] Suitable materials for this purpose include 17-4-PH steel powder with an average particle size of 10 µm and ZrO2 powder with a particle size in the nanometer range. Alternating layers with a thickness of approximately 50 µm (ZrO2) and 150 µm (steel) are printed using the two materials. The layers can also be gradually blended to ensure good mechanical stability between the layers. The heat treatment typically involves a debinding step at a temperature of 600°C and sintering at 1250°C.

Claims

[1] Method for producing an electrical energy converter, in which the production of at least one electrical conductor / conductor system and an electrical coil with coil carrier and a rotor (7) and / or stator (16) is carried out using a three-dimensional screen printing process using different screens and / or suspensions in individual layers formed one above the other, where after formation of a respective layer, a fixation, preferably by means of drying, and after formation of the three-dimensional shape, a sintering of the element, which until then was present as a green body, is carried out and in the process Electrically and / or magnetically non-conductive parts are manufactured using ceramic powder directly next to electrically and / or magnetically conductive areas as insulators. [2] An electrical energy converter produced by a method according to claim 1, comprising at least one stator (16), rotor (7), electrical conductor / conductor system and an electrical coil with a coil carrier, wherein an electrical conductor / conductor system and an electrical coil with a coil carrier and a rotor (7) and / or stator (16) are formed as three-dimensional monolithic elements consisting of individual electrically conductive, magnetically conductive, magnetically non-conductive, electrically non-conductive, magnetic and / or magnetizable materials sintered together in layers, wherein electrically and / or magnetically non-conductive parts have been produced with ceramic powder directly next to electrically and / or magnetically conductive areas as insulators. [3] Energy converter according to claim 2, characterized by that it is a composite component produced generatively from ceramic and / or metallic materials. [4] Energy converter according to claim 2 or 3, characterized by that individual parts of at least one element selected from the rotor (7), stator (16), electrical conductor / conductor system and electrical coil with coil carrier consist of different materials sintered together. [5] Energy converter according to one of the preceding claims 2 to 4, characterized by that individual parts of at least one element selected from the rotor (7), stator (16), electrical conductor / conductor system and the electrical coil with coil carrier are formed from electrically conductive, magnetically conductive, magnetically non-conductive, electrically non-conductive, magnetic and / or magnetizable materials. [6] Energy converter according to one of the preceding claims 2 to 5, characterized bythat cavities or openings (3, 4) for a flow of a temperature control fluid are formed on at least one of the elements rotor (7), stator (16), electrical conductor / electrical conductor system and electrical coil with coil carrier. [7] Energy converter according to one of the preceding claims 2 to 6, characterized by that electrical conductors (14), electrical connection contacts, electrical conductor tracks, magnetic conductors, permanent magnets (11), electrical insulators, magnetic insulators, fastening elements (1), bearing seats, sensors and / or commutators are formed on at least one of the elements rotor (7) or stator (16). [8] Energy converter according to one of the preceding claims 2 to 7, characterized bythat in the region of an opening of a cavity or an opening for the flow of a tempering fluid there is an element compressing the fluid in the direction of the cavity or opening or in the opposite direction, preferably with at least one blade-shaped element. [9] Energy converter according to one of the preceding claims 2 to 8, characterized by that in the at least one element selected from rotor (7), stator (16), electrical conductor / conductor system and electrical coil with coil carrier, which is manufactured as a monolith from several different materials, no chemical organic component is contained. [10] Energy converter according to one of the preceding claims 2 to 9, characterized by that porous areas are present on at least one element selected from the rotor (7), stator (16), electrical conductor / conductor system and coil carrier. [11] Energy converter according to one of the preceding claims 2 to 10, characterized by that the magnetic flux and / or electric current can be guided in a defined three-dimensional form due to isotropic and / or anisotropic material properties and / or introduced material combinations. [12] Energy converter according to one of the preceding claims 2 to 11, characterized by that electrical conductors in one or more coil(s) have / have a conductor geometry that deviates from the classical geometry, preferably a polygonal one. [13] Energy converter according to one of the preceding claims 2 to 12, characterized by that the thermal conductivity can be locally adjusted in three-dimensional form by means of isotropic and / or anisotropic material properties and / or introduced material combinations and / or their characteristics in the area of ​​the material transitions / boundaries.

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