Sheet for a laminated core of an electrical machine with improved insulation and method for producing such a sheet

Abstract

A sheet (11, 14) for a laminated core (10, 13) of an electrical machine (1) is disclosed. The sheet (11, 14) comprises an annular base section (15) made of soft iron with recesses (16) for receiving a winding (12) of the electrical machine (1), wherein the base section (15) is produced by printing and sintering a soft iron base material. The sheet (11, 14) also comprises an edge section (17) made of an insulating material adjacent to the base section (15) in the region of the recesses (16), which edge section is produced by printing and sintering an insulating base material. Furthermore, a laminated core (10, 13) with such laminated cores (11, 14), an electrical machine (1) with such a laminated core (10, 13), a vehicle with such an electrical machine (1) and methods for producing laminated cores (11, 14) for a laminated core (10, 13) and for producing a laminated core (10, 13) are disclosed.

Description

TECHNICAL FIELDThe invention relates to a sheet metal for a laminated core of an electric machine, wherein the sheet metal comprises an annular base section made of soft iron with recesses for receiving a winding of the electric machine, and wherein the base section is produced by printing and sintering a soft iron base material. The invention furthermore relates to a laminated core which comprises a plurality of laminations of the aforementioned type stacked one above the other. The invention also relates to an electric machine comprising a stator and a rotor which is rotatable in relation to the stator, wherein the stator has a stator laminated core of the aforementioned type and / or wherein the rotor has a rotor laminated core of the aforementioned type. Furthermore, the invention relates to a vehicle which is driven by an electric machine as defined above. Finally, the invention relates to methods for producing a sheet metal for a laminated core of an electric machine and for producing a laminated core with such a sheet metal.PRIOR ARTA sheet metal, a laminated core, an electric machine, a vehicle and methods of the aforementioned type are known in the prior art. Generally, slot insulation is introduced into the slots of the laminated core before the windings of the electric machine are produced. In this way, the windings are electrically insulated from the laminated core. For this purpose, use is often made of dedicated folded paper sheets or dedicated plastic parts. By attaching these insulating parts, the manufacturing process of the electric machine is unfortunately complicated and time-consuming. In addition, an additional process step is necessary for producing the desired insulating parts before the assembly of the electric machine. If different types of electric machines are to be produced, different insulating parts must be produced and stored in the store.DISCLOSURE OF THE INVENTIONAccordingly, it is an object of the invention to provide an improved sheet metal, an improved laminated core, an improved electric machine, an improved vehicle and improved methods for producing sheets and a laminated core. In particular, a solution is to be proposed which simplifies the production process of the electric machine and accelerates production.The object of the invention is achieved by a laminated core according to the disclosure in the introductory paragraph, which additionally comprises an edge portion of an insulating material, which is produced by printing and sintering an insulating base material, adjacent to the base portion in the region of the recesses.In addition, the object according to the invention is achieved by a laminated core which comprises a plurality of laminations of the aforementioned type stacked one above the other.The laminated core, for example, a) can be designed as a stator laminated core, wherein the edge section is arranged radially inward from the base section in the case of an inner rotor machine or is arranged radially outward from the base section in the case of an outer rotor machine, or b) can be designed as a rotor laminated core, wherein the edge section is arranged radially outward from the base section in the case of an inner rotor machine or is arranged radially inward from the base section in the case of an outer rotor machine.Furthermore, the object according to the invention is achieved by an electric machine comprising a stator and a rotor which is rotatable relative to the stator, wherein the stator comprises a stator laminated core according to case a) of the aforementioned type and / or wherein the rotor comprises a rotor laminated core according to case b) of the aforementioned type.In addition, the object of the invention is also achieved by a vehicle having an electric machine of the aforementioned type, which is provided for driving the vehicle.In addition, the object of the invention is achieved by a method for producing a sheet metal for a laminated core of an electric machine, which method comprises the steps of:printing an annular base portion having recesses for receiving a coil of the electric machine with a soft iron base material,printing an edge portion with an insulating base material adjacent to the base portion in the region of the recesses; andheating and sintering the sheet.Here, the heating and sintering of the sections of the sheet metal take place simultaneously. This means that all the sections are first printed and then all the sections are simultaneously heated and sintered. The base portion and the edge portion may be printed in any desired order. In particular, the base portion may be printed first and then the edge portion may be printed.The object of the invention is also achieved by an alternative method for producing a sheet metal for a laminated core of an electric machine, which method comprises the steps:printing an annular base portion having recesses for receiving a coil of the electric machine with a soft iron base material,heating and sintering the base portion,printing an edge portion with an insulating base material adjacent to the base portion in the region of the recesses; andheating and sintering the edge portion.Here, the heating and sintering of the sections of the sheet metal are carried out in two steps. That is, in a first step, the base portion is printed and then heated and sintered, and in a second step, the edge portion is printed and then heated and sintered. Accordingly, the base portion is already fixed when the edge portion is printed.Finally, the object of the invention is achieved by a method for producing a laminated core of an electric machine, which method comprises the steps:stacking a plurality of sheets of the aforementioned type or stacking a plurality of sheets produced by one of the methods of the aforementioned type, andjoining together the edge portions of the plurality of sheets by heating them at least locally up to the melting point of the insulating material.By means of the proposed measures, an insulation for the laminated core is produced in accordance with the production of the sheets, and no additional parts have to be produced and stored on bearings. Accordingly, the manufacturing process of the electric machine is simplified and accelerated.In an advantageous embodiment, the base section and / or the edge section is / are printed by means of a screen printing method. In this way, the base portion and / or the edge portion can be printed very quickly. For example, the base portion is printed in a first step and the edge portion is printed in a second step. However, it is also possible to print the base section and / or the edge section by means of a jet printing method. Mixed embodiments are also possible. The base portion can be printed, for example, by using a screen printing method (in particular in a first step), and the edge portion can be printed by using a jet printing method (in particular in a second step).The insulating material can preferably contain or consist of plastic, ceramic, glass or paper. The insulating base material can accordingly also contain or consist of plastic, ceramic, glass or paper. All of these materials can be printed and provide good to very good electrical insulation. Some of the materials may be melted, for example ceramic, glass and thermoplastic. If the heating and sintering of the sections of the sheet metal takes place simultaneously, it is advantageous if the melting points of the soft iron and of the insulating material are similar. Accordingly, it is then advantageous to use an insulating material which contains or consists of ceramic and / or glass.In addition, if the edge portions of the plurality of sheets are joined to each other by being heated at least locally to the melting point of the insulating material, the stability of the laminated core and the insulating property of the edge portions can be improved. The edge sections connected to one another basically form a type of insulating housing. In particular, the edge portions of the plurality of sheets can be joined to one another by means of laser welding.Furthermore, it is very advantageous if the heating and sintering of the base section is effected by means of induction heating and the heating and sintering of the edge section is effected by means of heat transfer from the base section to the edge section. In this manner, the magnetic conductivity of the soft iron is used to concentrate the heat to the base portion so as to separately melt the soft iron particles in the base portion. In contrast, the insulating material of the edge portion is not actively heated but is melted by the heat transfer from the base portion to the edge portion. In some embodiments, the melting point of the soft iron may be substantially higher than the melting point of the insulating material. However, the proposed measures allow both the soft iron and the insulating material to be sintered very well without overheating the insulating material and underheating the soft iron.BRIEF DESCRIPTION OF THE DRAWINGSNow, the present invention will be described in more detail with reference to specific embodiments, but the present invention is not limited thereto. FIG. 1 shows a half-sectional view of an example electric machine; FIG. 2 is a front view of an example sheet metal; FIG. 3 is a detailed view of the sheet of FIG. 1 ; and FIG. 4 shows a schematic view of an electric vehicle.DETAILED DESCRIPTIONGenerally, the same parts or similar parts are identified with the same / similar designations and reference numerals. The features disclosed in the specification apply to parts having the same / similar labels. Details regarding an alignment and relative position relate to the associated figure.FIG. 1 shows a schematic cross-sectional view of an exemplary electric machine 1. the electric machine 1 comprises a rotor shaft 2 with a rotor 3 mounted thereon, wherein the rotor shaft 2 is mounted in (roller) bearings 4 a, 4 brotatable about a rotor axis RA and relative to a stator 5 of the electric machine 1. In addition, the electric machine 1 comprises a first bearing plate 6 in which the first bearing 4 ais arranged, a second bearing plate 7 in which the second bearing 4 bis arranged, and a stator housing 8 in which the stator 5 is installed. The bearing plates 6, 7 and the stator housing 8 together form the machine housing 9 of the electric machine 1 or are at least parts thereof.The stator 5 comprises a stator laminated core 10 with a plurality of stator laminations 11 stacked one above the other along the stator axis or the rotor axis RA. The stator 5 furthermore comprises stator windings 12 arranged in the stator laminated core 10.The rotor 3 comprises a laminated rotor core 13 with a plurality of stacked rotor laminations 14 along the rotor axis RA. The rotor 3 furthermore comprises rotor windings or rotor magnets (both not shown) which are arranged in the rotor laminated core 13.FIG. 2 shows a front view of one of the stator laminations 11. the stator laminations 11 each have an annular base structure 15 made of soft iron with recesses 16 for receiving the stator windings 12, wherein the recesses 16 open to an inner edge B or outer edge C of the base structure 15. The base portion 15 is formed by printing and sintering a soft iron base material.FIG. 3 shows a detailed view of the stator lamination 11 of FIG. 2 As can be seen, the stator lamination 11 comprises an edge portion 17 made of an insulating material adjacent to the base portion 15 in the region of the recesses 16.A method for producing a stator lamination 11 can comprise the following steps:printing the annular base section 15 with recesses 16 for receiving a stator winding 12 of the electric machine 1 with a soft-iron base material,printing the edge portion 17 with an insulating base material adjacent the base portion 15 in the region of the recesses 16; andheating and sintering the sheet 11.Here, the heating and sintering of the sections 15, 17 of the stator lamination 11 take place simultaneously. This means that all the sections 15, 17 are first printed and then all the sections 15, 17 are simultaneously heated and sintered. The base portion 15 and the edge portion 17 may be printed in any desired order. In particular, the base portion 15 may be printed first and then the edge portion 17 may be printed.An alternative method for producing a stator lamination 11 can comprise the following steps:printing the annular base section 15 with recesses 16 for receiving a stator winding 12 of the electric machine 1 with a soft-iron base material,heating and sintering the base portion 15,printing the edge portion 17 with an insulating base material adjacent the base portion 15 in the region of the recesses 16; andheating and sintering the edge portion 17.Here, the heating and sintering of the sections 15, 17 of the stator lamination 11 take place in two steps. That is, in a first step, the base portion 15 is printed and then heated and sintered, and in a second step, the edge portion 17 is printed and then heated and sintered. Accordingly, the base portion 15 is already fixed when the edge portion 17 is printed.Generally, any applicable printing method may be used for printing the base portion 15 and the edge portion 17. In an advantageous embodiment, the base section 15 and / or the edge section 17 is / are printed by means of a screen printing method. In this way, the base portion 15 and / or the edge portion 17 can be printed very quickly. For example, the base portion 15 is printed in a first step and the edge portion 17 is printed in a second step. However, it is also possible to print the base section 15 and / or the edge section 17 by means of a jet printing method. Mixed embodiments are also possible. The base portion 15 can be printed, for example, by using a screen printing method (in particular in a first step), and the edge portion 17 can be printed by using a jet printing method (in particular in a second step).The insulating material can preferably contain or consist of plastic, ceramic, glass or paper. The insulating base material can accordingly also contain or consist of plastic, ceramic, glass or paper. All of these materials can be printed and provide good to very good electrical insulation. Some of the materials may be melted, for example ceramic, glass and thermoplastic.It is very advantageous if the heating and sintering of the base section 15 is effected by means of induction heating and the heating and sintering of the edge section 17 is effected by means of heat transfer from the base section 15 to the edge section 17. In this manner, the magnetic conductivity of the soft iron is used to concentrate the heat to the base portion 15 so as to separately melt the soft iron particles in the base portion 15. In contrast, the insulating material of the edge portion 17 is not actively heated but is melted by the heat transfer from the base portion 15 to the edge portion 17. In some embodiments, the melting point of the soft iron may be substantially higher than the melting point of the insulating material. However, the proposed measures allow both the soft iron and the insulating material to be sintered very well without overheating the insulating material and underheating the soft iron.In general, a stator laminated core 10 can be produced by simply stacking a plurality of laminations 11 one above the other. However, it is advantageous if the edge sections 17 of the plurality of sheets 11 are connected to one another by heating them at least locally to the melting point of the insulating material. In this way, the stability of the stator laminated core 10 and the insulating capacity of the edge portions 17 can be improved. The edge sections 17 connected to one another basically form a type of insulating housing. In particular, the edge portions 17 of the plurality of stator laminations 11 may be joined together by laser welding.The examples set forth so far relate to a stator lamination 11 and a stator lamination stack 10. However, the present measures apply equally to a rotor lamination 14 and a rotor lamination stack 13. In the foregoing disclosure, a rotor lamination stack 14 may thus replace a stator lamination stack 11, and a rotor lamination stack 13 may replace the stator lamination stack 10. The rotor 3 of the electric machine 1 can therefore comprise a (rotor) laminated core 13. In more general language, the term "stator lamination" may be replaced with "lamination", and the term "stator lamination stack" may be replaced with "lamination stack".Generally, in the case of a stator lamination stack 10, the edge portion 17 may be disposed radially inward of the base portion 15 for an inner rotor machine or may be disposed radially outward of the base portion 15 for an outer rotor machine. In the case of a rotor laminated core 13, the edge section 17 can be arranged radially outwards from the base section 15 for an inner rotor machine or can be arranged radially inwards from the base section 15 for an outer rotor machine.By means of the proposed measures, an insulation for the laminated core 10, 13 is produced in accordance with the production of the sheets 11, 14, and no additional parts have to be produced and stored on bearings. Accordingly, the manufacturing process of the electric machine 1 is simplified and accelerated.FIG. 4 finally shows an electric vehicle 18 having an electric machine 1 according to the preceding definition, which is provided for driving the electric vehicle 18. In detail, the electric machine 1 is coupled to an optional transmission 19, side shafts 20 and finally to the wheels 21. The electric machine 1 may be provided to permanently propel the electric vehicle 18 in a fully electric vehicle or temporarily, e.g., in combination with an internal combustion engine, in a hybrid vehicle.It should be noted that the invention is not limited to the embodiments disclosed here above, but combinations of the different variants are possible. In practice, the electric machine 1 and the electric vehicle 18 may have more or fewer parts than shown in the figures. It is also noted that the electric machine 1 and the electric vehicle 18 or parts thereof are not necessarily drawn to scale in the figures. Furthermore, the description may include the subject matter of further independent inventions. It should also be noted that the use of a transmission 19 is not obligatory and that the electric vehicle 18 can only be driven by the electric machine 1 alone.It should also be noted that the term "comprises / comprises" does not exclude other elements and the use of the articles "a / an" does not exclude the plural form. Furthermore, elements described in connection with various embodiments may be combined. It is also noted that reference numerals in the claims should not be construed as limiting the scope of the claims.List of reference characters1 Electric machine 2 Rotor shaft 3 Rotor 4 a, 4 bMount 5 Stator 6 First bearing plate 7 Second bearing plate 8 Stator housing 9 Machine housing 10 Laminated core (stator laminated core) 11 Sheet (stator sheet) 12 Stator winding 13 Laminated core (rotor laminated core) 14 Sheet (rotor sheet) 15 Base section 16 Cutout 17 Edge section 18 Vehicle 19 Transmission 20 Side shaft 21 Wheel RA axis (rotor axis / stator axis) B Inner edge of the ring structure C Outer edge of the ring structure

Claims

Sheet (11, 14) for a laminated core (10, 13) of an electric machine (1) comprising an annular base section (15) made of soft iron with recesses (16) for receiving a winding (12) of the electric machine (1), wherein the base section (15) is produced by printing and sintering a soft-iron base material, characterized by - an edge section (17) made of an insulating material adjacent to the base section (15) in the region of the recesses (16), which is produced by printing and sintering an insulating base material.Sheet (11, 14) according to Claim 1, characterized in that the insulating material contains or consists of plastic, ceramic, glass or paper.Laminated core (10, 13) comprising a plurality of laminations (11, 14) according to one of Claims 1 to 2 stacked one above the other.Laminated core (10, 13) according to Claim 3, characterized in that the laminated core (10, 13) is designed as a stator laminated core (10), wherein the edge section (17), in the case of an inner rotor machine, is arranged radially inward of the base section (15) or, in the case of an outer rotor machine, is arranged radially outward of the base section (15), or b) is designed as a rotor laminated core (13), wherein the edge section (17), in the case of an inner rotor machine, is arranged radially outward of the base section (15) or, in the case of an outer rotor machine, is arranged radially inward of the base section (15).Electric machine (1) comprising a stator (5) and a rotor (3) which is rotatable relative to the stator (5), characterized in that - the stator (5) comprises a stator laminated core (10) according to case a) of claim 4 and / or - the rotor (3) comprises a rotor laminated core (13) according to case b) of claim 4.Vehicle (18) driven by an electric machine (1) according to claim 5.Method for producing a sheet (11, 14) for a laminated core (10, 13) of an electric machine (1), comprising the following steps: - printing an annular base section (15) with recesses (16) for receiving a winding (12) of the electric machine (1) with a soft-iron base material, - printing an edge section (17) adjoining the base section (15) in the region of the recesses (16) with an insulating base material, and - heating and sintering the sheet (11, 14).Method for producing a sheet (11, 14) for a laminated core (10, 13) of an electric machine (1), comprising the following steps: - printing an annular base section (15) with recesses (16) for receiving a winding (12) of the electric machine (1) with a soft-iron base material, - heating and sintering the base section (15), - printing an edge section (17) adjoining the base section (15) in the region of the recesses (16) with an insulating base material, and - heating and sintering the edge section (17).Method according to claim 7 or 8, characterized in that the base portion (15) and / or the edge portion (17) is / are printed by means of a screen printing method.Method according to one of Claims 7 to 9, characterized in that the heating and sintering of the base section (15) is effected by means of induction heating and the heating and sintering of the edge section (17) is effected by means of heat transfer from the base section (15) to the edge section (17).Method for manufacturing a laminated core (10, 13) for an electric machine (1), comprising the following steps: - stacking a plurality of sheets (11, 14) according to one of claims 1 or 2 or stacking a plurality of sheets (11, 14) manufactured by a method according to one of claims 7 to 10, and - joining together the edge portions (17) of the plurality of sheets (11, 14) by heating them at least locally up to the melting point of the insulating material.Method according to claim 11, characterised in that the edge sections (17) of the plurality of sheets (11, 14) are connected to one another by means of laser welding.

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