Abstract
At least one permanent magnet for an electrical machine is produced by first producing a permanently magnetic base body by compression molding or extrusion. A first partial region of the base body is separated from at least one second partial region of the base body by a cutting process. At least one permanent magnet is provided by the first partial region. The at least one permanent magnet is provided with a cavity by the cutting process.
Claims
1-10. (canceled)
11. A method for producing at least one permanent magnet for an electrical machine, the method comprising: producing a permanently magnetic base body by compression molding or extrusion; separating a first partial region of the base body from at least one second partial region of the base body by a cutting process, wherein the at least one permanent magnet is provided by the first partial region; and providing the at least one permanent magnet with a cavity by the cutting process, wherein the separation of the first partial region from the second partial region and the provision of the at least one permanent magnet with the cavity are carried out in a single step.
12. The method of claim 11, wherein the cutting process uses jet cutting.
13. The method of claim 12, wherein the jet cutting is water jet cutting.
14. The method of claim 11, wherein the cavity is a blind hole.
15. The method of claim 11, wherein the cavity is a through opening.
16. The method of claim 11, wherein the cavity extends in meandering manner.
17. The method of claim 11, wherein the at least one permanent magnet is produced in a shape of a triangle.
18. The method of claim 11, wherein the base body is produced as a cuboid or in a shape of a trapezium.
19. The method of claim 11, wherein the at least one permanent magnet includes at least one positive-locking element configured to so that the at least one permeant magnet is connected by the positive-locking element with a positive fit to a carrier of the electrical machine.
20. A permanent magnet for an electrical machine, wherein the permanent magnet is produced by: producing a permanently magnetic base body by compression molding or extrusion; separating a first partial region of the base body from at least one second partial region of the base body by a cutting process, wherein the at least one permanent magnet is provided by the first partial region; and providing the at least one permanent magnet with a cavity by the cutting process, wherein the separation of the first partial region from the second partial region and the provision of the at least one permanent magnet with the cavity are carried out in a single step.
Description
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0029] In the drawing:
[0030] FIG. 1 shows a schematic representation of a first part of a method for producing at least one permanent magnet according to a first embodiment for an electrical machine, in particular formed as an axial flux machine;
[0031] FIG. 2 shows a schematic representation of a second part of the method according to FIG. 1;
[0032] FIG. 3 shows a schematic perspective view of the permanent magnet according to its second embodiment, before the permanent magnet is provided with a cavity;
[0033] FIG. 4 shows a schematic perspective view of the permanent magnet provided with the cavity according to the second embodiment;
[0034] FIG. 5 shows a schematic top view of the permanent magnet according to its third embodiment;
[0035] FIG. 6 shows a schematic cross-sectional side view of the permanent magnet according to FIG. 5;
[0036] FIG. 7 shows a schematic top view of the permanent magnet according to its fourth embodiment;
[0037] FIG. 8 shows a schematic cross-sectional side view of the permanent magnet according to the fourth embodiment;
[0038] FIG. 9 shows a further schematic top view of the permanent magnet according to the third embodiment;
[0039] FIG. 10 shows a schematic front view of a die for the extrusion of a base body for the production of the permanent magnet;
[0040] FIG. 11 shows a schematic front view of the base body, from which the permanent magnet is produced according to its fifth embodiment;
[0041] FIG. 12 shows a schematic front view of the base body, from which the permanent magnet is produced according to its sixth embodiment;
[0042] FIG. 13 shows a schematic front view of the base body, from which the permanent magnet is produced according to a sixth embodiment; and
[0043] FIG. 14 shows a schematic front view of the base body, from which the permanent magnet is produced according to the fifth embodiment.
[0044] In the figures, the same or functionally identical elements are provided with the same reference numerals.
DETAILED DESCRIPTION
[0045] Based on FIGS. 1 and 2, a method for producing permanent magnets 10a-d according to a first embodiment for an electrical machine formed as an axial flux machine is described hereinafter. This means that the permanent magnets 10a-d are used in the aforementioned axial flux machine, i.e., are components of the axial flux machine in the completely produced state of the axial flux machine. In particular, the permanent magnets 10a-d are used for a rotor of the axial flux machine, so that in the completely produced state of the axial flux machine, the permanent magnets 10a-d are components of the rotor of the axial flux machine.
[0046] In a first step S1 of the method, a permanently magnetic i.e., a permanent magnet base body 12 is produced by compression molding or extrusion. The permanently magnetic base body 12 is shown in FIG. 1 in a schematic top view labelled A1 and in a schematic side view labelled A2. It is apparent that in the case of the first embodiment, the permanently magnetic base body 12 is produced as a rectangular or cuboid-shaped, in particular solid, block by compression molding or preferably by extrusion. FIG. 1 shows furthermore sub-steps S2.1, S2.2 and S2.3 of a second step S2 of the method. During the second step S2 of the method, in particular following the first step S1, the base body 12 and therefore the permanent magnets 10a-d, which are produced from the preferably extruded, permanently magnetic base body 12, are provided with cavities 14a-d, also referred to as contours or having a respective contour, by an cutting process presently embodied as jet cutting, in particular in such a way that the permanently magnetic base body 12 is provided with the cavities 14a-d in such a way that the permanent magnet 10a is provided with the cavity 14a, the permanent magnet 10b is provided with the cavity 14b, the permanent magnet 10c is provided with the cavity 14c and the permanent magnet 10d is provided with the cavity 14d, thus the respective permanent magnet 10a-d is provided with at least or exactly one of the respective cavities 14a-d. During a third step S3 of the method, for example following the second step S2, partial regions 16a-d of the base body 12 are each separated from one another and preferably also from at least or exactly one other partial region or from several, other partial regions of the base body 12 by jet cutting, wherein the permanent magnets 10a-d are provided by the partial regions 16a-d in such a way that the permanent magnet 10a is provided by the partial region 16a, the permanent magnet 10b is provided by the partial region 16b, the permanent magnet 10c is provided by the partial region 16c and the permanent magnet 10d is provided by the partial region 16d. In other words, the partial regions 16a-d of the base body 12 are used as the permanent magnets 10a-d. In particular, it is provided during the third step S3 that the partial regions 16a-d and therefore the permanent magnets 10a-d are cut to shape by the jet cutting and thereby in particular are produced or provided with an outer circumferential shape or contour or geometry. The respective other partial region of the base body 12 is also referred to as an offcut and is labelled in FIG. 2 with 18, so that the partial regions 16a-d are separated, i.e., cut off, from one another and from the offcut by the jet cutting. In the completely produced state of the permanent magnets 10a-d, which are also simply referred to as magnets, the magnets are individual magnets, thus separately formed components, and in the completely produced state of the permanent magnets 10a-d, the permanent magnets 10a-d have the cavities 14a-d. The respective, completely produced permanent magnet 10a-d is therefore a jet-cut and extruded magnet, whereby in particular the following advantages can be achieved: [0047] elimination of additional connecting technology [0048] smaller cutting length [0049] lower number of process steps [0050] reduced process times
[0051] The permanent magnets 10a-d can be produced therefore particularly time-efficiently and cost-effectively. Due to the provision of the permanent magnets 10a-d with the cavities 14a-d, eddy current losses in the permanent magnets 10a-d can additionally be kept particularly low.
[0052] Advantageously, the jet cutting is carried out with optimized cutting lengths. It has furthermore proven to be particularly advantageous when water jet cutting is used for the jet cutting. During the jet cutting it is, in particular, provided that a cutting tool, also referred to for example as a tool, provides and therefore radiates a cutting jet, also referred to as a jet, in particular along a jet direction. Preferably, the cutting jet is formed from a liquid, for example containing at least water, and therefore as a liquid jet, in particular as a water jet, wherein for the separation of the partial regions 16a-d and for the production of the cavities 14a-d, the cutting jet is radiated for example along the jet direction on the base body 12, meaning that it is radiated onto the respective partial region 16a-d and/or 18. Furthermore stated in other words, for example during the production of the cavity 14a-d and during the separation of the partial regions 16a-d, the base body 12 is acted upon by the cutting jet, in particular along the jet direction.
[0053] Preferably, it is provided that the separation of the partial regions 16a-d from one another and from the respective other partial region 18 and the provision of the base body 12 and therefore the permanent magnets 10a-d with the cavities 14a-d is carried out in one step, i.e., uninterrupted, so that between the separation of the partial regions 16a-d from one another and from the respective partial region 18 and the provision of the base body 12 with the cavities 14a-d, an interruption of the jet cutting, i.e., an end to the provision of the cutting jet by the tool is omitted.
[0054] It is particularly recognizable from FIGS. 1 and 2 that the respective cavity 14a-d at least substantially extends in a meandering manner. The respective cavity 14a-d is therefore a cavity of a respective surface 20 or of a respective outer circumferential lateral surface of the respective permanent magnet 10a-d. Furthermore, it is recognizable from FIG. 2 that the respective permanent magnet 10a-d is produced in the shape of a triangle, i.e., in its completely produced state it has a triangular shape. In the exemplary embodiment shown in FIGS. 1 and 2 it is provided that the respective permanent magnet 10a-d has the shape of a triangle, wherein two sides of the triangle are formed straight, and the third side of the triangle is arched, in particular circularly arched.
[0055] FIG. 3 shows the permanently magnetic base body 12, from which the permanent magnet 10a shown in FIG. 4 is produced according to the second embodiment. The base body 12 is produced by extrusion, so that the base body 12 is an extruded profile, in particular a solid extruded profile. In particular, it is preferably provided that the base body 12 is formed as a single piece. The base body 12 is provided with the cavity 14a which, as is recognizable from FIG. 4, extends in a meandering manner.
[0056] FIGS. 5 and 6 show a third embodiment of the permanent magnet 10a. From FIGS. 5 and 6 it is particularly clearly recognizable that the cavity 14a, for example, is produced as a blind hole or in the manner of a blind hole, so that the cavity 14a does not penetrate the permanent magnet 10a completely along the jet direction, but instead is restricted by a wall region W of the permanent magnet 10a.
[0057] FIGS. 7 and 8 show a fourth embodiment of the permanent magnet 10a. In the fourth embodiment the cavity 14a is formed as a through opening or in the manner of a through opening, which completely penetrates the permanent magnet 10a. It is particularly clearly recognizable from FIGS. 5 to 8 that the permanent magnet 10a is provided with exactly one cavity 14a by the jet cutting, wherein the cavity 14a extends continuously, i.e., uninterrupted. Therefore, for example for the production of the third embodiment, the jet cutting is carried out as a cutting-in method, in order to produce the cavity 14a as a blind hole or in the manner of a blind hole. For the production of the fourth embodiment, the jet cutting is carried out as a cutting-through method, by means of which the cavity 14a is formed as a through opening.
[0058] It is conceivable that as the cutting process, by means of which the partial regions 16a-d are separated from one another and from the offcut and the permanent magnets 10a-d are provided with the cavities 14a-d, laser cutting, i.e., a laser cutting process, is used so that the cutting jet is an energy jet or a laser jet. Furthermore, it is conceivable that wire cutting EDM is used as the cutting process. In particular by using wire cutting EDM as the cutting process, the cutting process can be carried out in a particularly advantageous manner as the previously described cutting-through method, whereby for example the cavity 14a can be particularly advantageously produced as a through opening.
[0059] FIG. 9 shows another schematic top view of the permanent magnet 10a-d according to the third embodiment. It is recognizable that the cavity 14a can have at least or exactly two straight-line longitudinal regions extending diagonally or perpendicular to one another. Alternatively, or additionally, the arched, in particular meandering, cavity 14a can have longitudinal regions. In particular, the cavity 14a is formed by at least or exactly one cutting line, which is produced by the cutting process. The cutting line can extend in at least one first longitudinal region horizontally and/or at least one second longitudinal region at an angle. In other words, respective longitudinal regions of the cavity 14a can be arranged at an arbitrary angle, in particular to one another. In FIG. 9, an angle is labelled with a, which is enclosed by a longitudinal region, labelled L and substantially at least extending in a straight line, of the cavity 14a and an edge K, in particular formed as a cutting edge, of the base body 12.
[0060] FIG. 10 shows a die 21 in a schematic front view, which is produced during the extrusion and therefore for the extrusion of the base body 12. FIG. 11 shows a fifth embodiment of the base body 12, which is produced by means of the die 21 according to FIG. 10. The die 21 has an opening 22, through which a semi-finished product, from which the base body 12 according to FIG. 11 is produced, is forced. From FIG. 11 it is recognizable that the base body 12 according to the fifth embodiment, in particular in relation to its cross section, has the shape of a trapezium.
[0061] FIG. 12 shows a sixth embodiment of the base body 12. In the sixth embodiment, the base body 12 has positive-locking elements 24 and 26, wherein preferably the permanent magnet 10, which is produced from the base body 12, has the positive-locking elements 24 and 26 in its completely produced state. The respective positive-locking element 24 or 26 is, for example, a tongue and groove element, which is arrangeable in a corresponding receiver, formed, for example, as a groove, of a carrier of the axial flux machine, in such a way that the permanent magnet 10a can be connected with a positive fit to the carrier, i.e., can be attached to the carrier, by means of the positive-locking elements 24 and 26. The positive-locking elements 24 and 26 are for example produced by the extrusion and/or the cutting process.
[0062] FIG. 13 shows the base body 12 according to a seventh embodiment. In the seventh embodiment as well, the base body 12 and the permanent magnet 10a, which is produced from the base body 12, have a positive-locking element 28, which, for example, can be formed as a tongue and groove element. Therefore, the preceding and following embodiments for the respective positive-locking elements 24 or 26 are transferable to the positive-locking element 28 and vice versa. Usually, in electrical machines, magnets are connected with a carrier such as a rotor core of the rotor of the electrical machine by adhesive bonds. The adhesive bonds and the magnets are exposed to high, critical temperatures and loads. The respective positive-locking element 24, 26 or 28 makes it possible to connect the respective permanent magnets 10a-d to the carrier, like, for example, the rotor core, not or not only in an integral manner, but the respective permanent magnet 10a-d can be connected with a positive fit by means of the respective positive-locking element 24, 26 or 28 to the carrier formed in particular as a rotor core. Therefore, a particularly secure mechanical fixing of the respective permanent magnet 10a-d on the carrier can be achieved. In particular, the respective permanent magnet 10a-d can be mechanically connected with a positive fit by means of the respective positive-locking element 24, 26 or 28 to the carrier, whereby particularly high forces or torques can be transferred. Also, the trapezium shape of the base body 12 and particularly of the fully produced permanent magnet 10a-d shown in FIG. 11 enables a particularly advantageous positive-fit attachment of the respective permanent magnet 10a-d to the carrier.
[0063] FIG. 14 shows another schematic front view of the base body 12 according to the fifth embodiment. In FIG. 14, the cutting jet is labelled 30. In the embodiment shown in FIG. 14, the cutting jet 30 is a water jet. It is recognizable that the cutting jet 30 or the jet direction thereof forms an angle ? with the vertical V, which is different from 0? and from 180? and in particular less than 90?. At the angle ?, the base body 12 is acted upon with the cutting jet 30. It is recognizable that the cutting jet 30 or the jet direction thereof forms another angle ? with a surface 20 of the base body 12, whose surface 20 is acted upon with the cutting jet 30, wherein the angle ? and the angle ? add up to 90?. The angles ? and ? can be the same size or different sizes from one another. This produces the trapezoidal shape of the base body 12 and therefore of the permanent magnet 10a-d. In particular, the trapezium shape makes it possible to attach the permanent magnets 10a-d with a mechanically positive fit to the carrier.
[0064] Although the invention has been illustrated and described in detail by way of preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived from these by the person skilled in the art without leaving the scope of the invention. It is therefore clear that there is a plurality of possible variations. It is also clear that embodiments stated by way of example are only really examples that are not to be seen as limiting the scope, application possibilities or configuration of the invention in any way. In fact, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete manner, wherein, with the knowledge of the disclosed inventive concept, the person skilled in the art is able to undertake various changes, for example, with regard to the functioning or arrangement of individual elements stated in an exemplary embodiment without leaving the scope of the invention, which is defined by the claims and their legal equivalents, such as further explanations in the description.
LIST OF REFERENCE NUMERALS
[0065] 10a-d Permanent magnet [0066] 12 Base body [0067] 14a-d Cavity [0068] 16a-d Partial region [0069] 18 Other partial region [0070] 20 Surface [0071] 21 Die [0072] 22 Opening [0073] 24 Positive-locking element [0074] 26 Positive-locking element [0075] 28 Positive-locking element [0076] 30 Cutting jet [0077] K Edge [0078] L1 Longitudinal region [0079] A1 Top view [0080] A2 Side view [0081] S1 First step [0082] S2 Second step [0083] S2.1 Sub-step [0084] S2.2 Sub-step [0085] S2.3 Sub-step [0086] S3 Third step [0087] V Vertical [0088] W Wall region [0089] ? Angle [0090] ? Angle [0091] ? Angle
