Arrangement of a stator with a polymer housing for a dynamoelectric machine and production process or use for it

Abstract

The invention relates to a process which is intended for producing an arrangement comprising a stator (STT) and a housing (OCS) for a dynamoelectric machine and in which a number of stator laminations (SMS) are put together to form a laminated core (SMP). The production process comprises: - arranging the stator laminations (SMS) in a stack along an axial direction to form a laminated core (SMP) and - applying a composite polymer (GPF) to at least the radial outer side of the laminated core (SMP) such that one or more applied layers of the filled composite polymer (GPF) at least partially form(s) the housing (OCS). A composite polymer is a polymer in the form of a matrix in which particles are embedded. In addition, the invention also relates to an arrangement comprising a stator (STT) and a housing (OCS) of a dynamoelectric machine and also the use thereof for a process for producing or processing foodstuffs, pharmaceutical products or cosmetic products.

Description

[0001] Description

[0002] Arrangement of a stator with a polymer housing for a dynamoelectric machine and its manufacturing method or use

[0003] The invention relates to a method for producing an assembly comprising a stator and a housing for a dynamoelectric machine, in which a number of stator laminations are assembled to form a laminated core, comprising stacking the stator laminations to form a laminated core along an axial direction. In addition, the invention also relates to an assembly comprising a stator and a housing of a dynamoelectric machine, and to the use of such an assembly for a process for producing or processing food, pharmaceutical products, or cosmetic products.

[0004] Electrical or electrodynamic machines, such as electric motors, are usually encapsulated in an aluminum housing after the copper winding has been inserted and impregnated. This housing serves as a passivation against environmental influences and as a heat sink for the motor. The metal or aluminum housing, which often features cooling fins to facilitate heat transfer to the convective air, is shrunk in an energy-intensive process.

[0005] A spindle motor with a coated laminated core and a dedicated housing is already known from US 6 753 628 Bl.

[0006] From WO 2022 / 017653 A1 it is already known to fix stator laminations to one another on a radial inner side by means of a composite polymer.

[0007] Especially small axle heights - i.e. a small distance between the center of the motor shaft and a mounting surface arranged parallel to the motor shaft - are sold very cheaply on the market due to price pressure, which makes economical production while maintaining the quality requirements of the motors ever more demanding.

[0008] Based on the problems and disadvantages of the prior art, the object of the invention is to further develop a method of the type defined above in such a way that the manufacturing costs are reduced while maintaining the same quality and function.

[0009] To achieve the object according to the invention, a method of the type defined above is proposed with the additional features of the characterizing part of independent claim 1. In addition, the invention proposes a corresponding arrangement comprising a stator and a housing of a dynamoelectric machine, as well as the use of such an arrangement for a process for producing or processing foodstuffs, pharmaceutical products, or cosmetic products. The respective dependent subclaims contain advantageous developments of the invention.

[0010] The invention is particularly well-suited for the use of the arrangement according to the invention in a process for the production or processing of food, pharmaceutical products, or cosmetic products because the inventive use of the composite polymer makes a design particularly easy to achieve for hygienically demanding processes. In particular, a hygienically advantageous encapsulation of the stator laminations can be easily implemented.

[0011] In detail, the invention provides that after the stator laminations have been stacked to form a laminated core along an axial direction, a filled composite polymer, which can also be referred to in more functional terminology as a gap filler medium, is applied to the laminated core at least on the radial outer side, so that one layer or several applied layers of the filled composite polymer at least partially form or form the housing. The filled composite polymer is a polymer composite material. It is therefore a composite material, also called a composite material, made of two or more materials bonded to one another. The filled composite polymer is designed as a particle composite material, as a particle composite or dispersion material. Particles are embedded in a matrix of polymer material or a polymer or plastic.

[0012] The inventive replacement of the housing with a correspondingly designed laminated core significantly reduces the manufacturing costs of dynamoelectric machines or motors. Cost reductions in the manufacturing process of these machines have previously been achieved through classic, minor design changes, which, on the one hand, saved material and, on the other hand, potentially shortened production time. The invention takes a different approach, by which a previously crucial component can be replaced.

[0013] The housing according to the invention - formed by the outer contour of the laminated core, which is provided with a layer of the gap filler medium, meets all mechanical requirements.

[0014] The outer contour of the laminated core is protected against external influences such as gases, liquids, and especially corrosive substances by the filled composite polymer. The filled composite polymer creates a visually closed and smooth surface, giving the product a high-quality impression. The housing, which is at least partially made of the filled composite polymer, represents a cost-effective yet high-quality solution.

[0015] According to an advantageous development, the housing that surrounds the laminated core consists of at least 50% to 100% of a radial housing wall thickness from one layer or several applied layers of the filled composite polymer. According to an advantageous development, the filled composite polymer has a viscosity of at least 1000 mPas at room temperature. The room temperature is preferably the ambient temperature in the room where processing takes place. This temperature is generally around 15° - 22°C, preferably 17° - 19°C.

[0016] According to an advantageous development, the filled composite polymer has an addition of solvent to reduce the viscosity between 0 wt. % and 5 wt. %. This means that the filled composite polymer can advantageously have no addition of solvent to reduce the viscosity, so that, for example, no edge drift can occur. Edge drift is the surface tension-induced withdrawal of a liquid layer, e.g. a layer of paint, from radii. The uniform wetting and enclosure with a layer as thick as would occur, for example, on a flat surface successfully prevents edge drift. In order for this to succeed, it is advantageous if the base material is very highly viscous and thixotropic.

[0017] To enable spray application, it is advantageous to make the filled composite polymer sprayable using a rapidly evaporating solvent. The additive is particularly suitable for selecting and measuring such that significant portions evaporate during spraying and the desired viscosity is achieved upon contact with the surface.

[0018] An advantageous development of the invention provides that the filled composite polymer contains particles. The particles comprise at least one ingredient of: thermally conductive particles, in particular containing boron nitride (BN) and / or aluminum oxide (Al2O3) and / or quartz powder and / or fused silica, flame-retardant particles, in particular aluminum hydroxide (Al(OH)3), electrically insulating particles, in particular mica. An advantageous development of the invention provides that the filled composite polymer is a thixotropic liquid. When applied by spraying - even with a suitable composition with a solvent - the layer of the filled composite polymer becomes highly viscous immediately upon impact and remains adhered to radii with a homogeneous layer thickness, even on radii.

[0019] A particularly advantageous development of the invention provides for the filled composite polymer to be thixotropic before application by adding a thixotropic agent. An inorganic thickener can be added in a suitable amount for thixotropic purposes.

[0020] An advantageous development of the invention provides that the filled composite polymer is designed as a highly filled composite polymer. The highly filled composite polymer can have a particle content of up to 80 wt. %.

[0021] The invention also relates to an arrangement comprising a stator and a housing of a dynamoelectric machine, in which a number of stator laminations are arranged in stacks to form a laminated core along an axial direction adjacent to a laminated core, the stator laminations having an axial gap to one another at least in some regions, the laminated core being provided at least radially on the outside with a layer of a filled composite polymer, so that the applied layer of the filled composite polymer at least partially forms the housing. This arrangement is preferably produced by a method according to at least one of claims 1-12 or by a method described herein according to the invention or a development of the invention.

[0022] An advantageous development of the invention provides that at least some stator laminations have at least one rib section which continues radially outwards relative to the adjacent circumferential contour and which extends at least over a section of the circumference.

[0023] To create the cooling fin structure on the final outer contour of the motor, it is preferable for the laminated core itself, i.e., the individual stator laminations, to have a corresponding outer contour punching. This implementation of the cooling fins can be achieved without additional effort, and the stator laminations dissipate the heat output from the stator without additional resistance, for example, from transitions between the laminations and a shrunk-on housing.

[0024] Furthermore, the invention relates to a use of the arrangement according to the invention according to claim 11, 12 or 13 or an application of the method for a process for producing or processing food, pharmaceutical products or cosmetic products.

[0025] The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more understandable in light of the following description and embodiments, which are described in more detail in the context of the drawings. This following description does not limit the invention to the embodiments included. The same components or parts may be identified by the same reference numerals in different figures. It is understood that a preferred embodiment of the present invention may also be any combination of the dependent claims or the embodiments described herein with the features of the respective independent claim. In the drawings:

[0026] Figure 1 is a schematic, simplified representation of a method according to the invention as a flow chart,

[0027] Figure 2 is a schematic, simplified, three-dimensional representation of a laminated core without ribs,

[0028] Figure 3 is a schematic, simplified, three-dimensional representation of a laminated core with ribs, Figure 1 is a schematic, simplified representation of a method for producing an arrangement ARG comprising a stator STT and a housing OCS for a dynamoelectric machine as a flow chart in a sequence of steps (a), (b).

[0029] The stator STT comprises a number of stator laminations SMS, which are assembled into a laminated core SMP, as shown in Figures 2 and 3. In Figure 3, the individual stator laminations SMS have a rib section RPS that extends radially outward relative to the adjacent circumferential contour and extends over at least a portion of the circumference.

[0030] Step (b) provides that a filled composite polymer GPF is applied to the laminated core SMP at least on the radial outer side, so that one layer or several applied layers of the filled composite polymer GPF at least partially forms, preferably completely, the outer housing OCS of the dynamoelectric machine.

[0031] Before step (b) is initiated, it is first determined how the application process APP is to be carried out. Various options are available for this. Application can be carried out by: pouring CST, spreading PNT, brushing BRS, thick film brushing TLB, knife coating SQG, spatula coating SPT, injection moulding PRI. Depending on this, a viscosity range (VRG) of the filled composite polymer (GPM) of 3,000-1,000,000 mPas is specified. For this purpose, it is intended that for application by means of pouring CST, spreading (PNT), brushing BRS, the viscosity VSC is in the range up to 10,000 mPas and for application by spatula or injection moulding the viscosity is specified in the range from 10,000 mPas.

[0032] Starting from the determined viscosity range VRG, a viscosity of the filled composite polymer GPM is produced by admixing thickeners and / or admixing particles (no PRT) and / or by thixotroping (TXP). The filled composite polymer GPM is produced as a highly filled composite polymer GPM with a PRT particle content of up to 80 wt.%. Thixotroping is preferably carried out by adding an inorganic thickener ATH or by adding 0.1-5 wt.%, preferably 0.1-2 wt.% of fumed silica ARL. In this way, the filled composite polymer GPF is produced as a thixotropic liquid which, at room temperature and without solvent, is a highly viscous material. After application, it remains dimensionally stable similar to a paste and wets and encloses substrate edges and curves in a homogeneous layer.

[0033] A gap filler, which has, for example, epoxy, PU, ​​or PEI as a matrix, can be used as a filled composite polymer (GPF). This filled composite polymer (GPF) is solvent-free and can be filled with, for example, thermally conductive particles (such as BN, Al2O3, quartz powder, fused silica), flame-retardant particles (such as Al(OH)3), or electrically insulating particles (mica, and the previously mentioned). Solvents for reducing viscosity should not be used in a potting / encapsulation application, as the solvent cannot be removed from thick layers without creating pores, foaming effects, and general defects. A viscosity range of 3,000-1,000,000 mPas is advantageous, whereby flowable (e.g. pourable, brushable, dispensable, but not sprayable) filled composite polymers GPF are more likely to be at the lower end of the interval and higher viscosity from approx. 10,000 mPas can be applied by spatula or injection.

[0034] A crucial aspect of spray processing is that a highly viscous system, particularly from the gap filler or potting compound class, can be designed to have a low viscosity, <5000 mPas, for a very short time (significantly shorter than that of conventional paints) from application until the desired wetting of the substrate. This means that an additive spraying of a top coat onto an irregular substrate surface (cooling fin radii and sheet metal edges of the outer contour) is possible without having to accept the disadvantages of conventional paint systems (capillation between the sheets, edge alignment). By making the formulation "sprayable", the need for design freedom for the outer housing contour is met.

[0035] A short-term reduction in viscosity and making the product sprayable is preferably achieved by two combined measures.

[0036] 1. Thixotropy of the gap filler / potting material, which can be achieved either on the basis of Aerosil (pyrogenic silica), i.e. an inorganic additive at approx. 0.1-2 wt. %, or by admixing inorganic thickeners, as described, for example, in application WO2015197647A1 by BYK (Altana Group). Both methods result in the viscosity being significantly reduced under shear (to the value of the starting material without thixotropic agent), but increasing after a few seconds of rest to a value which can be a factor of 10-1000 higher, depending on the form and proportion of the thixotropic additive.

[0037] 2. To reduce the viscosity of the starting product, a compatible solvent (or a mixture of different solvents) should be used (5-40 wt.%), which has a low evaporation number (=relatively rapid evaporation, defined as the relative evaporation time compared to that of diethyl ether with 1). This reduces the mixed viscosity in the resting state of the material - thixotropic additive - solvent mixture, as required, to a sprayable viscosity (<5000 mPas).

[0038] During the spraying process itself, the material is subjected to a high shear force dependent on the nozzle geometry, whereby the thixotropy causes the overall viscosity to drop to its resting state value. After the homogeneous spray layer has been applied (10-60 pm), two viscosity-increasing effects superimpose themselves within seconds. Firstly, the viscosity increase due to thixotropy sets in within seconds (the sprayed layer "settles down"), and secondly, the solvent mixture with a low evaporation number (VDZ<1) quickly evaporates from the layer and thus gradually and sustainably increases the viscosity to the original height of the gap filler / potting compound. The sprayed material therefore has no time in its low-viscosity state to capillate significantly into the gap between the sheets, to escape at the edges ("edge escape") or to form drips.After the first layer has dried (a significant portion of the solvent has evaporated, so that the layer appears optically dry and matt) a further layer can be applied within a few minutes. Due to the high "dry and rest viscosity" (= paste-like), the workpiece does not have to be stored in a rolling manner. Vertical and overhanging surfaces can also be sprayed. If desired, several layers can be applied using this process to achieve the desired coating effect (optically dense, corrosion protection, smooth surface, etc.). By using a two-component resin as a base, curing can be achieved at room temperature (or slightly elevated temperature if necessary). This eliminates the need for further thermal curing, resulting in a more flexible, faster and CO2-friendly process.

[0039] In one possible embodiment, a two-component gap filler material from Elantas (A component MC336, B component W363 TX) was used, which was thixotroped using an inorganic thickener from BYK (both Altana Group). Component A MC336 and component B W363 TX were mixed in a weight ratio of 100 to 7.5, and an additional 15 parts by weight of MEK was used as a highly volatile (low evaporation rate of 6) solvent.

[0040] The spraying is carried out using a commercially available compressed air spray gun. Approximately 30-50 μm can be applied per layer. The layer thickness, spray pattern, spray angle, etc. can be individually adjusted using pressure, horn pressure, nozzle geometry, feed speed and spray distance. A drying time of approx. 3 minutes, i.e. significant evaporation of the solvent (MEK), results in a matt surface at room temperature. The next layer can then be sprayed. With a triple coating, the sheet contour is covered by a homogeneous and continuous surface so that, viewed from the outside, its optical and physical properties are equivalent to a thin plastic casing. Capillation into the gaps between the sheets, edge alignment, runs and drips are prevented by the above-mentioned combined measures.This makes it possible to apply the coating using a spray process regardless of variance. The low layer thickness during a spraying process allows the solvent to diffuse quickly from the layer without the formation of defects (pores). Depending on the surface quality and optical requirements, additional layers or thicker individual layers can be applied. This can be adjusted using process parameters. A housing produced in this way is partially cured (touchable or non-adhesive) within a few hours at room temperature and fully cured after approximately 48 hours at room temperature. Optionally, this time can be shortened to a few hours by increasing the temperature, e.g., with an IR radiator.

[0041] For the filled composite polymer GPM, the material class of potting resins and gap fillers is preferably used, as their high filler content gives them a suitably high viscosity. A combination of thixotropy and solvent addition (with a suitable evaporation number) is preferably used to make the above-mentioned materials additively applicable (e.g. sprayable), while ensuring the highly viscous properties quickly after application. Application in several thin layers is advisable so that the solvent contained can diffuse out of the layer without forming pores. This initial drying, as well as the thickening that begins within seconds due to thixotropy, gradually produces a closed and continuous layer over the discontinuous substrate (individual sheet contours). This cannot be achieved with conventional coating systems.

[0042] Other methods for higher viscosity systems include spatulas, squeegees, and thick-film brushing. These methods are somewhat more difficult to apply due to the contours and are not easily automated.

Claims

Patent claims 1. A method for producing an arrangement (ARG) comprising a stator (STT) and a housing (OCS) for a dynamoelectric machine, in which a number of stator laminations (SMS) are assembled to form a laminated core (SMP), comprising: (a) Stacking the stator laminations (SMS) to form a laminated core (SMP) along an axial direction, characterized by (b) applying a curing filled composite polymer (GPF) at least to the radial outer side of the laminated core (SMP) so that one or more applied layers of the filled composite polymer (GPF) at least partially form the housing (OCS).

2. The method according to claim 1, wherein the filled composite polymer (GPF) is applied by spraying.

3. The method according to claim 1 or 2, wherein the housing (OCS) is formed of at least 50% to 100% of a radial housing wall thickness from one layer or several applied layers of the filled composite polymer (GPF).

4. The method according to claim 1, 2 or 3, wherein the filled composite polymer (GPF) has a viscosity of at least 1000 mPas at room temperature.

5. Process according to one of the preceding claims, wherein the filled composite polymer (GPF) has an addition of solvent for viscosity reduction between 0 wt.% to 5 wt.%.

6. A process according to any one of the preceding claims, wherein the filled composite polymer (GPF) contains particles, the particles comprising at least one ingredient of: - thermally conductive particles, in particular comprising boron nitride (BN) and / or aluminum oxide (A12O3) and / or quartz powder and / or fused silica, flame-retardant particles, in particular aluminum hydroxide (Al (OH) 3 ), - electrically insulating particles (ISO), in particular mica. A process according to any one of the preceding claims, wherein the filled composite polymer (GPF) is a thixotropic liquid. A process according to any one of the preceding claims, comprising - Thixotropicizing the filled composite polymer (GPF) by adding a thixotropic agent prior to application. The method according to claim 8, comprising: - Thixotroping the filled composite polymer (GPF) by adding an inorganic thickener (ATH). The method according to claim 9, comprising: - Thixotroping the filled composite polymer (GPM) by adding 0.1-5 wt.%, preferably 0.1-2 wt.%, of fumed silica (ARL). The method according to claim 9 or 10, comprising: - Specify an application process (APP) as one of: Pouring (CST), Brushing (PNT), Brushing (BRS), Thick Film Brushing (TLB), Squeegeeing (SQG), Spatula (SPT), Pressing (PRI), - Establishing a viscosity range (VRG) of the filled composite polymer (GPM) of 3,000-1,000,000 mPas depending on the specified application process (APP), the process being suitable for application by pouring (CST), brushing (PNT), pin- its (BRS), a viscosity (VSC) in the range up to 10,000 mPas is specified and for application by spatula or pressing, a viscosity in the range from 10,000 mPas is specified, - Producing the specified viscosity of the filled composite polymer (GPM) by admixing thickeners and / or admixing particles and / or by thixotroping (TXP). Process according to one of the preceding claims, wherein the filled composite polymer (GPM) is a highly filled composite polymer (GPM) with a particle content (PRT) of up to 80 wt. %. Process according to at least the preceding claim 2, wherein the filled composite polymer (GPM) is subjected to the following preparation steps to make it sprayable before being applied by spraying: a. Thixotroping using an inorganic additive and b. Addition of a solvent with an evaporation number VDZ<1.Arrangement comprising a stator (STT) and a housing (OCS) of a dynamoelectric machine, in which a number of stator laminations (SMS) are arranged in stacks to form a laminated core (SMP) along an axial direction adjacent to a laminated core (SMP), wherein the stator laminations (SMS) have an axial gap to one another at least in some regions, wherein the laminated core (SMP) is provided at least radially on the outside with a layer of a filled composite polymer (GPF), so that the applied layer of the filled composite polymer (GPF) forms the housing (OCS).

15. Arrangement (ARG) according to claim 14, wherein the arrangement (ARG) is manufactured according to a method according to at least one of claims 1-13.

16. Arrangement (ARG) according to claim 14 or 15, wherein at least some stator laminations (SMS) have at least one rib section (RPS) which continues radially outward relative to the adjacent circumferential contour and extends at least over a portion of the circumference.

17. Use of an arrangement (ARG) according to claim 14, 15 or 16 for a process for producing or processing food, pharmaceutical products or cosmetic products.

18. Use of a curing, thixotropic, filled composite polymer (GPF) as a housing (OCS) of a stator (STT) for a dynamoelectric machine.

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