DE102021210756A1 - Rotor for electric rotating machine, electric rotating machine, nacelle propulsion and watercraft - Google Patents

Abstract

The invention relates to a rotor (1) for an electric rotating machine (38) with a shaft (4) and an annular rotor element (3) which guides the magnetic field and is fastened to the outer circumference of the shaft (4) and which has a large number of individual electrical laminations (6) layered partial laminated cores (5) which are evenly distributed in the circumferential direction (U), arranged in rows in the axial direction (A) and held on the shaft (4) in a form-fitting manner, the partial laminated cores (5) being provided with permanent magnets (12) which are arranged adjacent to one another in the circumferential direction (U), characterized in that each partial laminated core (5) is coated at least circumferentially, in particular on all sides, with a metallic layer (44). The invention also relates to an electric rotating machine (38) with at least one such rotor (1), a gondola drive (37) with at least one such electric rotating machine (38) and a watercraft (36) with at least one such gondola drive (37).

Description

The invention relates to a rotor for an electrical rotating machine with a shaft and an annular rotor element, which guides the magnetic field and is attached to the outer circumference of the shaft, which has a large number of laminated part stacks made up of layers of individual electrical laminations, which are evenly distributed in the circumferential direction, arranged in rows in the axial direction and are connected in a form-fitting manner the shaft are held, wherein the partial laminated cores are provided with permanent magnets which are arranged adjacent to each other in the circumferential direction. Furthermore, the invention relates to an electrical rotating machine with at least one such rotor, a nacelle drive with at least one such electrical rotating machine and a watercraft with at least one such nacelle drive.

Electric rotating machines are used in ships, among other things, for so-called gondola drives, which are also referred to as rudder propellers. The characteristic core feature of such gondola drives is a slim design with a small outer diameter of a machine housing that accommodates the electric motor in order to achieve optimal hydrodynamic behavior with high torque density at the same time. Here, the comparatively small outer diameter of the rotor element of the electric motor that guides the magnetic field proves to be disadvantageous, since the rotor element has to be greatly lengthened to generate torque, which increases the electrical losses. To further compensate for such losses, permanent magnet excitation is often used in nacelle drives. However, the rotor design required for this is a significant cost factor. In addition, the physical limits of the magnet system are quickly reached. An example in this context is the EP 3 629 446 A1 described rotor design referenced, in which the permanent magnets are positioned buried in the circumferential direction next to each other along a single imaginary circular line on the rotor element guiding the magnetic field. With such a rotor design, which is referred to below as “conventional rotor design”, sufficient thermal stability of the permanent magnets is required due to the high thermal utilization. This is achieved by using permanent magnets of a high temperature class, which normally have the very expensive alloy component dysprosium.

Proceeding from this state of the art, it is an object of the present invention to create a rotor of the type mentioned at the outset, an electrical rotating machine with at least one such rotor, a nacelle drive with at least one such electrical rotating machine and a watercraft with at least one such nacelle drive , which have an improved structure. In particular, a noticeable reduction in costs and/or an increase in the performance parameters is sought.

To solve this problem, the present invention provides a rotor of the type mentioned at the beginning, which is characterized in that each partial laminated core is coated at least circumferentially, in particular on all sides, with a metallic layer, the metallic layer preferably completely covering the partial laminated core. Thanks to such a metallic coating, the heat dissipation of the partial laminated cores to the outside is significantly improved, which leads to a reduction in the maximum temperature of the partial laminated cores during rotor operation. Due to the lower temperature level, significantly cheaper permanent magnets in a lower temperature class can be used. Alternatively, the rotor can be used at higher temperatures if the temperature class of the magnet material is not changed.

The metallic layer is advantageously a corrosion-resistant layer, in particular a zinc-based metallic layer. In this way, in addition to improved heat dissipation, protection against corrosion for the partial laminated cores can be provided at the same time.

Each partial laminated core preferably has a resin-based coating on its radially outer surface, in particular a coating based on epoxy resin, which is preferably applied directly to the metallic layer. Such a resin-based coating serves as an insulating layer.

According to one embodiment of the present invention, each laminated core stack is pushed axially onto the shaft and is provided with a sliding coating on its radially inner surface, at least in those areas that are in direct contact with the shaft. On the one hand, such a sliding coating facilitates the assembly of the partial laminated cores while being pushed onto the rotor. On the other hand, the anti-friction coating protects the metallic layer underneath during the assembly of the partial laminated cores. The anti-friction coating may include Teflon® to name just one example. The application can be done by spraying.

The permanent magnets are advantageously arranged in pairs in a V-shape, with each partial laminated core preferably having at least two permanent magnets, in particular at least four permanent magnets has magnets, which are arranged adjacent to one another in the circumferential direction to form V-shaped arrangements. Thanks to such a V magnet arrangement, in which the north and south poles are divided in the middle and the permanent magnets are set at a defined angle, the individual losses of the permanent magnets are, if the magnet dimensions of a conventional rotor design in width and height are taken over in total, lower than with the conventional rotor design. This avoids a physically conditioned critical magnet width in the manufacture of the permanent magnets. Since the total volume of the magnets remains the same, it is only divided, it is always guaranteed that the dimensions are not critical in terms of manufacturing technology. On the other hand, with an increase in the performance of a rotor that is constructed according to the conventional rotor design, there would be the risk of a significantly increased reject rate in the production of the permanent magnets. Furthermore, the V-arrangement ensures improved cooling of the magnets compared to the conventional rotor design in that they are cooled more evenly over the entire volume of the rotor element. Thanks to the V arrangement, it is therefore also possible to use less expensive magnet material as a result of the lower temperature levels. Alternatively, the rotor can be used at higher temperatures. Due to the increase in the magnetic flux and the overall higher thermal utilization, 15% of the total length of the rotor element that guides the magnetic field can also be saved. This leads to significant cost and weight savings compared to the conventional rotor design. In other words, this also means that compared to the conventional rotor design, a higher torque can be generated with the same construction volume. This increases the torque density by 15%. This enables a whole new level of flexibility in terms of rotor design. At the same time, the overall yoke height can be reduced compared to the conventional rotor design.

According to one embodiment of the present invention, two non-magnetic end plates are provided on each partial laminated core, which are mechanically braced with one another, the permanent magnets being pushed into receiving spaces formed by recesses provided in the electrical steel sheets and being fixed in them with a casting material. In this way, a simple and inexpensive construction is realized.

Each partial laminated core advantageously has cooling ducts which extend axially through the partial laminated core. In particular, these are positioned in such a way that they are located outside of the magnetic field generated by the permanent magnets, ie in such a way that they do not cause the magnetic field lines to become constricted. A cooling medium, for example cooling air, can be conducted through the cooling channels in order in this way to further reduce the operating temperature, which is accompanied by the advantages already described above.

At least one cooling channel preferably has a turbulator element inserted into it. Such turbulator elements bring about a noticeable improvement in the cooling performance by swirling the cooling medium. The turbulator element can have a spiral shape, for example, which imparts a twist to the cooling medium flowing through the cooling channel. The turbulator element can be designed as a sheet metal strip bent in a spiral shape, to name just one example. The turbulator element is preferably produced as a separate component, so that it can be inserted into the cooling channel as required or, alternatively, can also be omitted. A fixation of the turbulator element within the cooling channel is not absolutely necessary.

According to one embodiment of the present invention, cooling channels are provided, which are formed jointly by two adjacently arranged partial laminated cores. In this way, the available surface area of the electrical steel sheets can be optimally utilized.

Wall areas of at least some cooling channels are advantageously provided with a structure, in particular with a wave-like structure, through which the surface of the wall areas is enlarged compared to smooth wall areas and the cooling capacity is thus improved.

The surface of the shaft is preferably provided with a large number of grooves to increase the surface area, which is also associated with an increased cooling capacity.

Furthermore, the present invention provides an electrical rotating machine with at least one rotor according to one of the preceding claims to achieve the object mentioned in the introduction.

In addition, the present invention creates a nacelle drive with at least one electric rotating machine according to the invention.

In addition, the present invention creates a watercraft with at least one gondola drive according to the invention.

Finally, the present invention creates a watercraft with at least one gondola drive according to the invention.

• 1 eine perspektivische Ansicht eines Rotors gemäß einer ersten Ausführungsform der vorliegenden Erfindung;
• 2 eine perspektivische Ansicht eines Teilblechpakets des in 1 gezeigten Rotors;
• 3 eine Vorderansicht des in 2 gezeigten Teilblechpakets;
• 4 eine Rückansicht des in 2 gezeigten Teilblechpakets;
• 5 eine Vorderansicht analog zu 4, bei der eine Abdeckplatte abgenommen ist;
• 6 eine Vorderansicht eines Ausschnitts des in 1 gezeigten Rotors;
• 7 eine perspektivische Ansicht des in 6 gezeigten Ausschnitts;
• 8 eine perspektivische Längsschnittansicht eines Ausschnitts des in 1 gezeigten Rotors;
• 9 eine perspektivische Längsschnittansicht eines Ausschnitts einer alternativen Ausführungsform eines erfindungsgemäßen Rotors;
• 10 eine Vorderansicht eines Ausschnitts des in 1 gezeigten Rotors, der an seiner vorderen Stirnseite mit einem Radialventilator ausgeführt ist;
• 11 eine perspektivische Teilansicht des Rotors im Bereich des Radialventilators;
• 12 eine Vorderansicht eines Teilblechpakets gemäß einer zweiten Ausführungsform der vorliegenden Erfindung;
• 13 eine perspektivische Ansicht eines Turbulators;
• 14 eine perspektivische Ansicht des in 12 gezeigten Teilblechpakets;
• 15 eine Längsschnittansicht eines Teilbereiches einer Welle gemäß einer zweiten Ausführungsform der vorliegenden Erfindung; und
• 16 eine schematische Seitenansicht eines Wasserfahrzeugs gemäß einer Ausführungsform der vorliegenden Erfindung, das eine elektrische rotierende Maschine mit einem in 1 gezeigten Rotor aufweist.

Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. inside is

• 1 a perspective view of a rotor according to a first embodiment of the present invention;
• 2 a perspective view of a partial laminated core of the in 1 shown rotor;
• 3 a front view of the in 2 partial laminated core shown;
• 4 a rear view of the in 2 partial laminated core shown;
• 5 a front view analogous to 4 , in which a cover plate is removed;
• 6 a front view of a section of the in 1 shown rotor;
• 7 a perspective view of the in 6 shown section;
• 8th a perspective longitudinal sectional view of a section of the in 1 shown rotor;
• 9 a perspective longitudinal sectional view of a detail of an alternative embodiment of a rotor according to the invention;
• 10 a front view of a section of the in 1 shown rotor, which is designed at its front end with a radial fan;
• 11 a perspective partial view of the rotor in the area of the centrifugal fan;
• 12 a front view of a partial laminated core according to a second embodiment of the present invention;
• 13 a perspective view of a turbulator;
• 14 a perspective view of the in 12 partial laminated core shown;
• 15 a longitudinal sectional view of a portion of a shaft according to a second embodiment of the present invention; and
• 16 a schematic side view of a watercraft according to an embodiment of the present invention, having an electric rotating machine with an in 1 rotor shown.

1 shows a perspective view of a rotor 1 of an electric rotating machine, which is rotatable about an axis of rotation 2 . The axis of rotation 2 defines an axial direction A and a circumferential direction U. The rotor 1 comprises a rotor element 3 which conducts a magnetic field and which is fastened to the outer circumference of a shaft 4 which is designed to be hollow in this case. The rotor element 3 comprises a multiplicity of partial laminated cores 5 and has an outer diameter of preferably at least one meter. The partial laminated cores 5 are distributed uniformly in the circumferential direction U and are arranged in four rows in the axial direction A in the present case. Each partial laminated core 5 comprises a multiplicity of electrical laminations 6 , of identical design in the present case, for suppressing eddy currents, which are stacked in the axial direction A and are provided with non-magnetic end plates 7 and 8 on the face side. The electrical laminations 6 and the end plates 7 and 8 of a partial laminated core 5 are mechanically clamped together in the axial direction A, in this case using two clamping bolts 9. In the illustrated embodiment, the electrical laminations 6 are each provided with four essentially rectangular recesses 10, which together have four cuboid Form receiving spaces 11, in which permanent magnets 12 are inserted axially, as best shown in 5 can be seen. The receiving spaces 11 or the permanent magnets 12 are arranged in pairs in a V-shape, with the tip of each V-arrangement pointing radially inwards. Thus, the north and south poles are divided in the middle and set in a V-shape with a defined angle. The mutually facing free ends of two receiving spaces 11 forming a V-shaped arrangement are each connected to one another via an axially continuous hollow space 13 through which one of the clamping bolts 9 is guided. The gaps between the permanent magnets 12, the clamping bolts 9 and the electrical laminations 6 are cast with a casting material, such as epoxy resin, in order to fix the permanent magnets 12 and the clamping bolts 9 in place. The permanent magnets 12 are made, for example, from samarium-cobalt, neodymium-samarium-cobalt, aluminum-nickel-cobalt, neodymium-iron-boron, samarium-iron-nickel or from a mixture of at least two of the materials. In order to improve the magnetic flux, a through-opening 14 extending in the axial direction A and also filled with casting material is formed centrally between two permanent magnets 12 of the same polarity forming a V-shaped arrangement. Each partial laminated core 5 is forming a dovetail-like connection, as shown in synopsis 3 , 4 and 7 can be seen, positively pushed in the axial direction A onto the shaft 4, axially resilient to the secured and spring-biased radially outwards. For this purpose, the electrical lamination sheets 6, like the end plates 7 and 8, are provided on their outer end regions in the circumferential direction U with holding projections 15 which protrude radially inwards and which, in the assembled state, engage in a form-fitting manner around the dovetail-like rotor projections 16 which protrude radially outwards, as a result of which the form-fitting connection is achieved. To generate the radial bias of the pushed onto the shaft 4 partial laminated cores 5 are on the outer circumference of the shaft 4, as in the 8th and 9 shown, each in the region of the rotor projections 16 arranged axially in a row, radially inwardly extending blind holes 17 are provided, in which spring elements 18 are inserted, which press directly or indirectly via pressure bolts 19 radially outwards against clamping wedges 20, which are centered on the radial inside of each Partial laminated core 5 formed clamping wedge receiving grooves 21 are axially inserted and guided. Correspondingly, the pressure exerted by the spring elements 18 is transmitted via the clamping wedges 20 to the respective partial laminated core 5, as a result of which a radially prestressed positioning of the partial laminated core 5 is achieved. 8th shows an embodiment in which spring elements 18 in the form of helical springs are inserted in the blind holes, which press directly against the respective clamping wedge 20 from below. 9 shows another embodiment, in which spring elements 18 in the form of plate springs are arranged in each of the blind holes 17, which press from below against a pressure bolt 19, which is also positioned in each blind hole 17 and which can be radially mounted in the blind hole 17 via a captive lock 22 screwed into the blind hole 17 is movably fixed. Correspondingly, the spring elements 18 press indirectly via the pressure bolts 19 from below against the associated clamping wedges 20 6 and 7 realized via cover plates 23 made of non-conductive material, which, like the partial laminated cores 5, are pushed positively onto the shaft 4 in the axial direction A, forming a dovetail-like connection, rest against an axially outer partial laminated core 5 and are supported by stops 24 fixed axially on the shaft 4 Springs 25 are pressed against the corresponding partial laminated core 5. In the present embodiment, the springs 25 are helical springs which are pushed onto guide pins 27 which protrude outwards from the cover plates 23 and engage in receiving openings 26 provided on the stops 24 . The guide pins 27 are formed by two tubular pieces 28 with a semicircular cross section, which are formed on cover plates 23 arranged laterally adjacent to one another. In the present case, the stops 24 are plate elements shaped like ring segments, which are fixed to the outer circumference of the shaft 4 , for example inserted into a circumferential groove provided on the outer circumference of the shaft 4 and screwed to the shaft 4 . The individual stops 24 can be connected to one another to form a closed ring. The stops 24 can be connected, for example, via screw or rivet connections. The electrical steel sheets 6 and the end plates 7, 8 are provided laterally with cooling channel recesses 29, which are triangular in the present case, which are positioned in alignment with the guide pins 27 in the axial direction A, the cooling channel recesses 29 of adjacent partial laminated cores 5 together forming a diamond-shaped cooling channel 50, in which the upper corners are directly are arranged outside of the magnetic field generated by the permanent magnets 12, so that they do not cause constriction of the magnetic field lines. In the present case, further groove-shaped cooling channels 30 are introduced on the radial inside of the electrical laminations 6 between the holding projections 15, see FIG 3 until 5 . Yet another cooling channel 43 with a triangular cross-section in the present case, which is also positioned outside of the magnetic field, is provided above the clamping wedge 20, see here 6 . One of the end plates 7 has, as shown in 4 is best shown, a contour corresponding to the contour of the electrical laminations 6 without the recesses 10 for the permanent magnets 12 . Due to its shape, it forms a tight cover during the introduction of the casting material. The contour of the other end plate 8 essentially corresponds to the contour of the electrical steel sheets 6, see FIG 3 . However, this end plate 8 is provided with recesses 31 serving as filling openings for the casting material in the center on the radially outer side and at the outer ends. Furthermore, it also has no recesses 10 for the permanent magnets 12 . In addition, cavities 32 through which the clamping bolts 9 are guided are larger than the corresponding cavities 13 in the electrical steel sheets 6, so that these also form filling openings. In addition, on the radially outer side of the end plate 8 , long grooves 33 are introduced, into which assembly devices (not shown in detail) can engage, which are used during the insertion of the permanent magnets 12 into the receiving spaces 11 . Each partial laminated core 5 is as shown in 3 is indicated only schematically by a dashed line, in the present case coated on all sides with a metallic layer 44, the metallic layer 44 preferably covering the partial laminated core completely. The metallic layer 44 is in particular a corrosion-resistant layer, for example a metallic layer based on zinc. Furthermore, each partial laminated core 5 comprises a resin-based, in particular epoxy resin-based coating 45 on its radially outer surface, which is represented schematically by a dash-dot line and is preferably applied directly to the metallic layer 44 . In addition, each part In the present case, the laminated core 5 is provided, at least in those areas which are in direct contact with the shaft 4, with an anti-friction coating 46, which is shown schematically as a solid line and has, for example, Teflon®. It should be pointed out that the metallic layer 44 can also be applied only peripherally to the partial laminated core. In addition, the resin-based coating 45 and/or the anti-friction coating 46 are optional.

The 10 and 11 show a variant of the in 1 shown rotor 1, in which in the area of the stops 24 baffles 34 are arranged, which are positioned such that they form a radial fan 35. The deflection plates 34 can form a welded construction or assembly units with the stops 24, for example.

The rotor 1 described above is characterized in that thanks to the V-magnet arrangement, in which the north and south poles are divided in the middle and the permanent magnets 12 are set at a defined angle, the individual losses of the permanent magnets 12 are very low. This avoids a physically conditioned critical magnet width in the manufacture of the permanent magnets 12 . Furthermore, the V-arrangement ensures very good cooling of the permanent magnets 12 in such a way that they are cooled more evenly over the entire volume of the rotor element 3 guiding the magnetic field. In addition, thanks to the metallic layer 44 and the cooling channels 30, 47, 50, through which cooling air is conducted during operation, heat that is produced is dissipated well. It is thus possible to use inexpensive magnet material due to low temperature levels. Alternatively, the rotor 1 can be used at higher temperatures. Due to the high magnetic flux and the overall high thermal utilization, the rotor element 3 guiding the magnetic field can be made comparatively short. This leads to low costs. With longer training, a correspondingly high moment can be achieved. A further advantage is that the clamping bolts 9 do not have to be insulated separately, since they are insulated directly when the permanent magnets are cast. Also, only comparatively few individual parts and many standard parts are used in the production of the rotor 1, which also contributes to a reduction in costs. Thanks to the fact that the cover plates are made of non-conductive material, there are no losses at this point.

12 shows a partial laminated core 5 according to a second embodiment of the present invention, the structure of which essentially corresponds to that of the partial laminated cores 5 described above, which is why a new description is dispensed with in relation to the identical features. A first difference is that instead of the groove-shaped cooling ducts 30, cooling ducts 47 that are open towards the underside and are circular when viewed in cross-section are provided, into which, optionally, in 13 turbulator elements 48 shown can be used, as shown in 14 is shown. In the present case, the turbulator elements 48 are sheet metal strips which are bent in a spiral shape and are pushed axially into the cooling channels 47 . Another difference is that the surfaces of the cooling channel recesses 29 and cooling channels 30,43 are structured in a wavy manner in order to be able to better dissipate heat due to the increased surface area.

15 shows a section of a shaft 4 according to an alternative embodiment, the surface of which is provided with a large number of grooves 49 in order to increase the cooling capacity here as well. The grooves 49 can have a depth of between 0.5 and 1 mm, for example. To reduce the notch effect, the bottom of the groove should be rounded, for example with a radius in the range of 0.3 mm or the like.

16 shows a watercraft 36 with a gondola drive 37. The watercraft 36 is designed as a ship or alternatively as a submarine. The nacelle drive 37 is located below the water surface 41 and has an electric rotating machine 38 serving as a drive, which drives a propeller 42 . The electric rotating machine 38 is presently designed as a permanently excited synchronous machine and includes a stator 39 and a rotor 1 according to the invention, as has been described above. A gap 40 is formed between the stator 39 and the rotor 1, which in the present case is designed as an air gap.

Although the invention has been illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention as defined by the appended claims.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 3629446 A1 [0002]

Claims (14)

Rotor (1) for an electric rotating machine (38) with a shaft (4) and an annular rotor element (3) which guides the magnetic field and is fastened to the outer circumference of the shaft (4) and which has a large number of partial laminated cores (5 ) which are evenly distributed in the circumferential direction (U), arranged in rows in the axial direction (A) and held in a form-fitting manner on the shaft (4), the partial laminated cores (5) being provided with permanent magnets (12) which are arranged in the circumferential direction (U ) are arranged adjacent to one another, characterized in that each partial laminated core (5) is coated at least circumferentially, in particular on all sides, with a metallic layer (44). Rotor (1) after claim 1 , characterized in that the metallic layer (44) is a corrosion-resistant layer, in particular a zinc-based metallic layer. Rotor (1) after claim 1 or 2 , characterized in that each laminated core (5) has a resin-based coating (45) on its radially outer surface, in particular a coating based on epoxy resin, which is preferably applied directly to the metallic layer (44). Rotor (1) according to one of the preceding claims, characterized in that each laminated core (5) is pushed axially onto the shaft (4) and on its radially inner surface, at least in those areas which are in direct contact with the shaft (4), is provided with an anti-friction coating (46), which makes it easier to push the partial laminated cores (5) onto the shaft (4) during assembly of the rotor (1). Rotor (1) according to one of the preceding claims, characterized in that the permanent magnets (12) are arranged in pairs in a V-shape, each partial laminated core (5) preferably having at least two permanent magnets (12), in particular at least four permanent magnets (12), which are arranged adjacent to one another in the circumferential direction (U) to form V-shaped arrangements. Rotor (1) according to one of the preceding claims, characterized in that two non-magnetic end plates (7, 8) are provided on each laminated core (5), which are mechanically braced with one another, the permanent magnets (12) passing through the electrical laminations (6 ) Provided recesses (10) formed receiving spaces (11) are inserted and fixed in them with a potting material. Rotor (1) according to one of the preceding claims, characterized in that each laminated core (5) has cooling channels (30; 43; 47; 50) extending axially through the laminated core (5). Rotor (1) after claim 7 , characterized in that at least one cooling channel (47) has a turbulator element (48) inserted into it. Rotor (1) after claim 7 or 8th , characterized in that cooling channels (50) are provided, which are formed jointly by two adjacently arranged partial laminated cores (5). Rotor (1) according to one of Claims 7 until 9 , characterized in that wall areas of at least some cooling channels (30; 43; 47; 50) are provided with a structure, in particular with a wave-like structure. Rotor (1) according to one of the preceding claims, characterized in that the surface of the shaft (4) is provided with a plurality of grooves (45). Electrical rotating machine (38) with at least one rotor (1) according to one of the preceding claims. Gondola drive (37) with at least one electric rotating machine (38). claim 12 . Watercraft (36) with at least one gondola drive (37). Claim 13 .

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