METHOD FOR PRODUCING AN INTERMEDIATE PRODUCT FOR AN ELECTRICAL MACHINE, COMPRISING A STATOR LAMINATED CORE AND A HOUSING PART, CONNECTED THERETO, OF THE HOUSING

Abstract

A method for producing an intermediate product for an electrical machine includes supplying a mould for a housing part. A stator laminated core is laid inside the mould and the housing part is produced by introducing a molten metal alloy into the mould. The molten metal alloy comes directly into contact with the stator laminated core. The method relates to an electrical machine with such an intermediate product, and a vehicle with such an electrical machine.

Claims

1. Method for producing an intermediate product for an electrical machine, comprising the following steps: supplying a mould for a housing part, laying a stator laminated core inside the mould, and producing the housing part by introducing a molten metal alloy into the mould, wherein the molten metal alloy comes directly into contact with the stator laminated core.

2. Method according to claim 1, wherein the metal alloy is a magnesium alloy or an aluminium alloy, wherein in particular the aluminium alloy has a minimum content of 2% Si and/or 1% Mg.

3. Method according to claim 1, wherein the stator laminated core comes directly into contact with the molten metal alloy only at the circumference.

4. Method according to claim 1, wherein the stator laminated core comes directly into contact with the molten metal alloy at the circumference, and a) at an annular region of a first covering surface of the stator laminated core which is formed by a first stator laminate the stator laminated core, or b) at an annular region of a first covering surface of the stator laminated core which is formed by a first stator laminate of the stator laminated core and additionally at an annular region of a second covering surface of the stator laminated core which is formed by a last stator laminate of the stator laminated core.

5. Method according to claim 1, wherein a circumferential deviation of the stator laminated core from an ideal cylindrical shape and/or a circumferential surface roughness of the stator laminated core is at least 0.1 mm.

6. Method according to claim 1, wherein the molten metal alloy penetrates between the stator laminates of the stator laminated core.

7. Method according to claim 6, wherein outer edges of the stator laminates of the stator laminated core are rounded or bevelled.

8. Method according to claim 1, wherein the stator laminated core has a temperature of between 15°-25° C., or is heated to a temperature of 50°-200° C., before the molten metal alloy is introduced into the mould.

9. Electrical machine, comprising: a housing with a housing part, a stator,arranged in the housing,with a stator laminated core,and a rotor which is arranged in the housing and is rotatably mounted therein, wherein the intermediate product produced according to claim 1 is part of the said housing and part of the said stator, wherein the stator laminated core is cast with the housing part.

10. Vehicle with at least two axles, at least of which one is driven, wherein the said driving action is performed at least partially or for part of the time by the electrical machine according to claim 9.

11. Method according to claim 2, wherein the stator laminated core comes directly into contact with the molten metal alloy only at the circumference.

12. Method according to claim 2, wherein the stator laminated core comes directly into contact with the molten metal alloy at the circumference, and a) at an annular region of a first covering surface of the stator laminated core which is formed by a first stator laminate of the stator laminated core, or b) at an annular region of a first covering surface of the stator laminated core which is formed by a first stator laminate of the stator laminated core and additionally at an annular region of a second covering surface of the stator laminated core which is formed by a last stator laminate of the stator laminated core.

13. Method according to claim 2, wherein a circumferential deviation of the stator laminated core from an ideal cylindrical shape and/or a circumferential surface roughness of the stator laminated core is at least 0.1 mm.

14. Method according to claim 2, wherein the molten metal alloy penetrates between the stator laminates of the stator laminated core.

15. Method according to claim 2, wherein the stator laminated core has a temperature of between 15°-25° C., or is heated to a temperature of 50°-200° C., before the molten metal alloy is introduced into the mould.

16. Electrical machine, comprising a housing with a housing part, a stator, arranged in the housing, with a stator laminated core, and a rotor which is arranged in the housing and is rotatably mounted therein, wherein the intermediate product produced according to claim 2 is part of the said housing and part of the said stator, wherein the stator laminated core is cast with the housing part.

17. Method according to claim 3, wherein the stator laminated core comes directly into contact with the molten metal alloy at the circumference, and a) at an annular region of a first covering surface of the stator laminated core which is formed by a first stator laminate of the stator laminated core, or b) at an annular region of a first covering surface of the stator laminated core which is formed by a first stator laminate of the stator laminated core and additionally at an annular region of a second covering surface of the stator laminated core which is formed by a last stator laminate of the stator laminated core.

18. Method according to claim 3, wherein a circumferential deviation of the stator laminated core from an ideal cylindrical shape and/or a circumferential surface roughness of the stator laminated core is at least 0.1 mm.

19. Method according to claim 3, wherein the molten metal alloy penetrates between the stator laminates of the stator laminated core.

20. Method according to claim 3, wherein the stator laminated core has a temperature of between 15°-25° C., or is heated to a temperature of 50°-200° C., before the molten metal alloy is introduced into the mould.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0036] The present invention is explained in more detail below with reference to the exemplary embodiment shown in the schematic figure of the drawings. In the drawings:

[0037] FIG. 1 shows a schematic half-sectional view of an exemplary electrical machine;

[0038] FIG. 2 shows a first example for an intermediate product for the electrical machine;

[0039] FIGS. 3-9 show manufacturing steps in the production of the intermediate product;

[0040] FIG. 10 shows an example of an intermediate product in which the stator laminated core is secured axially on two sides in the housing part;

[0041] FIG. 11 shows an example of an intermediate product with cooling ducts;

[0042] FIG. 12 shows a front view of an exemplary stator laminated core;

[0043] FIG. 13 shows a detailed view of the outer edges of the stator laminates, and

[0044] FIG. 14 shows an electrical machine with an intermediate product of the proposed type which is installed in a vehicle.

DETAILED DESCRIPTION OF THE INVENTION

[0045] It should be noted at this point that identical parts in the different embodiments are provided with the same reference signs or the same component designations, in some cases with different indices. The disclosures of a component contained in the description may accordingly be transferred to another component with the same reference sign or the same component designation. Also, the positional data selected in the description, such as for example “top”, “bottom”, “rear”, “front”, “side” etc. relate to the figure directly described and illustrated, and in the event of a change in position, should be transferred accordingly to the new position.

[0046] FIG. 1 shows a half-section through a schematically illustrated electrical machine 1. The electrical machine 1 comprises a shaft 2 with a rotor 3 sitting thereon, wherein the shaft 2 is mounted by means of (roller) bearings 4a, 4b so as to be rotatable relative to a stator about a rotational axis A. In this example, the stator has a stator laminated core 6, comprising a plurality of stator laminates 5, and stator windings 7 arranged therein. Specifically, the first bearing 4a sits in a front end plate 8, and the second bearing 4b sits in a rear end shield 9. Furthermore, the electrical machine 1 comprises a (middle) housing part 10a which connects the front end shield 8 and the rear end shield 9 and also accommodates the stator laminated core 6. The front end shield 8, the rear end shield 9 and the housing part 10a in this example thus form the housing 11 of the electrical machine 1, the stator laminated core 6 with the stator windings 7 of its stator 12.

[0047] FIG. 2 shows an upper part of the stator laminated core 6 and the housing part 10a which together form an intermediate product 13a in the production of the electrical machine 1, in an isolated illustration.

[0048] The production of the intermediate product 13a is now illustrated schematically with the aid of FIGS. 3 to 9:

[0049] In a first step, not illustrated explicitly, a plurality of stator laminates 5 are produced (for example, stamped or laser cut) and stacked in a second step to form a stator laminated core 6. In a further step illustrated in FIG. 3, a mould is supplied for the housing part 10a. Only a first mould part 14, which has a feed duct 15, is illustrated here in FIG. 3. Here too, only the upper part of the first mould part 14 is illustrated in section. In a further step illustrated in FIG. 4, the stator laminated core 6 is laid inside the first mould part 14 of the mould. In a further step illustrated in FIG. 5, a second mould part 16 of the mould is moved towards the first mould part 14, wherein the stator laminated core 6 is already situated in the first mould part 14. In a further step illustrated in FIG. 6, the mould is closed. The (whole) mould is designated with the reference sign 17 in FIG. 6. In a further step illustrated in FIG. 7, a molten aluminium alloy, generally a molten metal alloy, is introduced into the mould 17 via the feed duct 15. The molten aluminium alloy here comes directly into contact with the stator laminated core 6. In a further step illustrated in FIG. 8, the mould 17 is opened after the molten aluminium which now forms the housing part 10a hardens. Lastly, the intermediate product 13a is removed from the mould 17 in a step illustrated in FIG. 9. In a further step which is not illustrated, the stator windings 7 can be attached, after which the resulting arrangement can be used for further assembly of the electrical machine 1. It should be noted at this point that the stator laminated core 6 can be pressed together in the axial direction by closing the mould 17 or by other measures such that the stator laminates 5 bear closely against one other when they come into contact with the molten aluminium. A magnesium alloy can, for example, also be used as the metal alloy.

[0050] In the case of the intermediate product 13a illustrated in FIG. 2, the production of which is illustrated with the aid of FIGS. 3 to 9, the stator laminated core 6 comes directly into contact with the molten aluminium alloy or with the housing part 10a only at the circumference. However, this is not the only foreseeable option. It is also conceivable that the stator laminated core 6 comes directly into contact with the molten aluminium alloy at the circumference and at an annular region of a first covering surface B of the stator laminated core 6 which is formed by a first stator laminate 5a of the stator laminated core, as is illustrated in FIG. 10 for the intermediate product 13b. In addition, the stator laminated core 6 can come directly into contact with the molten aluminium alloy at an annular region of a second covering surface C of the stator laminated core 6 which is formed by a last stator laminate 5b of the stator laminated core 6, as is likewise illustrated in FIG. 10 for the intermediate product 13b. In this way, the stator laminated core 6 is secured axially particularly well. Contact with the molten aluminium at only one of the covering surfaces B, C is possible. The stator laminated core 6 is then secured axially on just one side.

[0051] FIG. 11 shows a further exemplary embodiment of an intermediate product 13c in which cooling ducts 18, which are closed by fitting an outer and separately produced housing part 19, are cast in the housing part 10c. It would, of course, also be possible that the cooling ducts 18 are provided in the outer housing part 19. The arrangement illustrated in FIG. 11 can, after attachment of the stator windings 7, be used in turn for further assembly of the electrical machine 1. It should be noted at this point that it can also be provided here that the stator laminated core 6 comes into contact with the molten aluminium at the first covering surface B and possibly also at the second covering surface C.

[0052] In order to control temperature-related mechanical stresses which occur within the intermediate product 13a.. 13c within the operating range of the electrical machine 1 (for example, -40° C. to +180° C.), the stator laminated core 6 can have a certain temperature before the molten aluminium alloy is introduced into the mould 17. In particular, the temperature of the stator laminated core 6 can be between 15°-25° C. before the molten aluminium alloy is introduced into the mould 17. This is favourable in particular when the electrical machine 1 is more likely to be operated in a low temperature range. It is, however, also favourable if the stator laminated core 6 is heated to a temperature of 50°-150° C. before the molten aluminium alloy is introduced into the mould 17. This is advantageous if the electrical machine 1 is more likely to be operated in a high temperature range.

[0053] A form fit is generally formed between the stator laminated core 6 and the housing part 10a.. 10c by the proposed measures. This can be improved if the stator laminated core 6 deviates from an ideal cylindrical shape at the circumference. It is in particular advantageous if a circumferential deviation of the stator laminated core 6 from an ideal cylindrical shape is at least 0.1 mm. It is also particularly advantageous if a circumferential surface roughness of the stator laminated core 6 is at least 0.1 mm. FIG. 12 shows a front view of an example of a stator laminated core 6 which has a plurality of circumferential grooves 20 which can run in an axial direction or also, for example, helically and into which the molten aluminium can penetrate. As a result, the form fit between the stator laminated core 6 and the housing part 10a.. 10c is improved and relative rotation between them is effectively avoided. The stator laminated core 6 also has internal grooves 21 which receive the stator windings 7. In addition to the circumferential grooves 20 or as an alternative thereto, the circumferential surface roughness R can be at least 0.01 mm. It is therefore favourable to form the stator laminated core 6 so that it is not completely smooth at the circumference so that the molten aluminium can cling well to the notches and indentations of the stator laminated core 6.

[0054] It should be noted at this point that the molten aluminium may also penetrate to a certain depth between the stator laminates 5, 5a, 5b, as a result of which the form fit between the stator laminated core 6 and the housing part 10a.. 10c is further improved. This effect occurs especially when the outer edges of the stator laminates 5, 5a, 5b are rounded or bevelled. FIG. 13 shows a greatly enlarged detail of the housing part 10a in which the penetration of the molten aluminium between the stator laminates 5, 5a, 5b in the region of the bevelled edges D can be seen.

[0055] The outer edges of the stator laminates 5, 5a, 5b are advantageously kept rather rough such that they have a sort of microserration. For example, such microserration can be achieved by stamping burrs not being removed or not being provoked at all. If the stator laminates 5, 5a, 5b are laser or plasma cut, such serration can be achieved by corresponding activation of the laser or plasma beam. The stator laminates 5, 5a, 5b are then sort of toothed wheels with very fine serrations. It would, for example, also be conceivable to knurl the stator laminated core 6.

[0056] FIG. 14 finally shows the electrical machine 1 installed in a vehicle 22. The vehicle 22 has at least two axles, at least one of which is driven. Specifically, the electric motor 1 is connected to an optional transmission 23 and a differential gear 24. The half-shafts 25 of the rear axle are joined to the differential gear 24. Finally, the driven wheels 26 are mounted on the half-shafts 25. Driving of the vehicle 22 is performed at least partially or for part of the time by the electrical machine 1. This means that the electrical machine 1 may serve for solely driving the vehicle 22, or for example may be provided in conjunction with an internal combustion engine (hybrid drive).

[0057] In conclusion, it is established that the scope of protection is determined by the patent claims. The description and the drawings should, however, be used to interpret the claims. The features contained in the figures may be interchanged and combined with one another in an arbitrary fashion. In particular, it is also established that the devices illustrated may in reality also comprise more or alternatively fewer component parts than illustrated. In some cases, the illustrated devices or their component parts may also not be illustrated to scale and/or may be increased in size and/or reduced in size.