Rotor, electric motor, hydraulic pump and process

Abstract

The invention relates to a rotor (5) for an electric motor (3), in particular a hydraulic pump (1), comprising a rotor shaft (7) extending coaxially to an axis of rotation (6), a rotor core (8) through which the rotor shaft (7) extends coaxially and which has a laminated core (9) and several permanent magnets (10) arranged distributed in the circumferential direction (U) on and / or in the laminated core (9), and a core housing (11) made of plastic through which the rotor shaft (7) extends coaxially, which is rotationally fixed to the rotor shaft (7) and which contains a receiving space (12) in which the rotor core (8) is arranged. The laminated core (9) is formed by several axially stacked laminations (45) and has two opposite end faces (20, 46), namely a first end face (20) and a second end face (46). The manufacture of the rotor (5) can be simplified by the fact that the laminated core (9) has several positioning openings (22) which are distributed in the circumferential direction (U), which are open at the first end face (20) and extend axially through at least two laminations (45) and which are configured for magnetizing the permanent magnets (10) by means of a magnetizing tool (48).

Description

[0001] The present invention relates to a rotor for an internal rotor electric motor, in particular a hydraulic pump, according to the preamble of claim 1. The invention further relates to an electric motor equipped with such a rotor and to a hydraulic pump equipped with such an electric motor. Finally, the invention relates to a method for manufacturing such a rotor.

[0002] A rotor of this type is known from EP 3 913 770 A1 and comprises a rotor shaft extending coaxially to an axis of rotation around which the rotor can rotate in the electric motor, and an annular rotor core through which the rotor shaft extends coaxially and which has a laminated core, in particular consisting of several axially stacked laminations, and several permanent magnets arranged circumferentially distributed on the laminated core. The rotor also has an annular core housing made of plastic through which the rotor shaft extends coaxially, which is rotationally fixed to the rotor shaft and which contains an annular receiving space in which the rotor core is arranged rotationally fixed. The laminated core is formed by several axially stacked laminations and has two axially divergent end faces, forming a first end face and a second end face.In the well-known rotor, a comparatively high level of effort is expended to firmly connect the permanent magnets to the laminated core. For this purpose, the permanent magnets are inserted into magnet recesses formed on a radial outer surface of the core. Furthermore, tabs formed on the outer edges of the laminated core laminations are plastically deformed to grip the permanent magnets and fix them in the recesses.

[0003] The present invention addresses the problem of providing an improved embodiment for a rotor of the type described above, or for an electric motor equipped with such a rotor, or for a hydraulic pump equipped with such a rotor, or for a method for manufacturing such a rotor, which is characterized in particular by simplified manufacturability.

[0004] This problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0005] The invention is based on the general concept of equipping the laminated core with multiple positioning openings configured for magnetizing the permanent magnets using a magnetizing tool. For example, the magnetizing tool can have multiple positioning pins that engage axially in each of the positioning openings to align the rotor core with a predetermined relative position to the magnetizing tool. This allows the magnetization to be carried out with high precision and efficiency.

[0006] In the present context, a “configuration” is synonymous with a “design” and / or “setup” and / or “suitability”, so that the term “configured” is synonymous with the term “designed” and / or “setup” and / or “suitable”.

[0007] In detail, it is proposed according to the invention that the sheet metal stack has several positioning openings which are arranged distributed in the circumferential direction, which are open at the first end face and extend axially through at least two sheets and which are configured for magnetizing the permanent magnets by means of a magnetizing tool.

[0008] According to an advantageous embodiment, the positioning openings can be provided that they are only open at the first end face and extend axially only through some of the laminations. As a result, the positioning openings have only a small, negligible influence on the rotor's moment of inertia.

[0009] According to an advantageous embodiment, the positioning openings on the lamination stack can be arranged radially further inwards than the permanent magnets. This measure also contributes to the fact that the influence on the rotor's moment of inertia is negligible.

[0010] According to an advantageous embodiment, the number of positioning openings can be the same as the number of permanent magnets. Optionally, the positioning openings can also be arranged centrally between two adjacent permanent magnets in the circumferential direction. This optimizes the magnetization efficiency.

[0011] According to an advantageous embodiment, the core housing can be provided with an annular housing pot that defines the receiving space radially inside and radially outside as well as axially on one side, and an annular disc-shaped housing cover axially facing the first end face of the laminated core, which defines the receiving space axially on the other side and is rotationally fixed to the housing pot. This results in a two-part core housing with a compact design.

[0012] According to an advantageous embodiment, the housing pot can be injection-molded onto the rotor core or manufactured directly on the rotor core using injection molding. The injection molding of the housing pot onto the rotor core is carried out in such a way that the positioning openings on the first end face are accessible to the magnetizing tool before the housing cover is mounted, or if a housing cover is omitted. This means they are open and remain open, i.e., not covered by the housing pot. This allows the rotor core to be overmolded with the housing pot before the permanent magnets are magnetized, thereby fixing the laminations to each other and the permanent magnets to the lamination stack in position. This simplifies the handling of the rotor core and thus the manufacturing of the rotor.

[0013] According to an advantageous embodiment, it can be provided that the housing pot is injection-molded onto the rotor core in such a way that the housing pot rests axially against the second end face of the lamination stack and has an inner collar on the first end face of the lamination stack that radially overlaps the lamination stack and rests axially against it, and / or an outer collar that radially overlaps the lamination stack and rests axially against it.

[0014] According to an advantageous embodiment, the laminated core can have several magnet receiving openings, each containing one of the permanent magnets. These magnets extend axially through several of the laminations within the laminated core and are spaced radially from both a radial outer core surface and a radial inner core surface. This arrangement places the permanent magnets inside the laminated core, ensuring they are securely held radially in the magnet receiving openings by positive locking. This eliminates the need for the tabs and their plastic deformation, mentioned above with reference to EP 3 913 770 A1, for fixing the permanent magnets. This simplifies the manufacture of the rotor.

[0015] According to an advantageous embodiment, the magnet receiving openings on the first end face of the laminated core can be at least partially radially overlapped and axially covered by at least one of the laminations. Additionally or alternatively, the magnet receiving openings on the second end face of the laminated core can be at least partially radially overlapped and axially covered by at least one of the laminations. The radial overlap and axial covering result in axial fixation of the respective permanent magnet to the laminated core in the respective magnet receiving opening by means of a positive fit.

[0016] According to an advantageous embodiment, the positioning openings can be axially shorter, in particular shorter by at least the thickness of one sheet of the laminated core, than the magnet receiving openings. Specifically, the positioning openings can be axially at most half the length, and preferably at most one-quarter the length, of the magnet receiving openings. This also reduces the influence of the positioning openings on the rotor's inertial mass.

[0017] An electric motor according to the invention, which can be configured particularly for a hydraulic pump, comprises a stator and a rotor of the type described above, which is rotatably arranged or mounted in the stator about the axis of rotation. The electric motor is configured as an internal rotor, in particular such that the stator surrounds the rotor coaxially with the axis of rotation. Furthermore, the electric motor can be configured as a wet rotor, so that the rotor comes into contact with a fluid in the stator, for example, for cooling the rotor and / or the stator, in particular for cooling a stator winding. Particularly when the electric motor is used in a hydraulic pump, the fluid pumped by the hydraulic pump can simultaneously be passed through the electric motor to cool it.

[0018] A hydraulic pump according to the invention is equipped with a pumping device and an electric motor of the type described above for driving the pumping device. The pumping device can, for example, be a pumping impeller, impeller, vane, or the like. Advantageously, the pumping device can be connected to the rotor shaft in a rotationally fixed manner.

[0019] An inventive method for manufacturing a rotor of the type described above is based on the fact that the core housing comprises an annular housing pot that defines the receiving space radially inwards and radially outwards as well as axially on one side, and an annular disk-shaped housing cover facing the first end face of the laminated core, which defines the receiving space axially on the other side and is rotationally fixed and axially fixed to the housing pot. The inventive method comprises the following steps.

[0020] First, the rotor core with the lamination stack and the unmagnetized permanent magnets is provided and inserted into an injection mold.

[0021] The housing is then manufactured by injection molding onto the rotor core, leaving the positioning openings on the first end face of the sheet metal bundle unobstructed. In other words, the housing is injection molded onto the rotor core in such a way that the positioning openings on the first end face of the sheet metal bundle remain unobstructed.

[0022] Finally, after the housing pot has been injection-molded, the permanent magnets are magnetized using a magnetizing tool. This tool has several positioning pins, which are axially inserted into one of the positioning openings to position the rotor core relative to the tool. The positioning pins create a predetermined position of the rotor core relative to the magnetizing tool.

[0023] According to an advantageous embodiment, the injection mold used to manufacture or overmold the housing pot can have several positioning pins which are axially inserted into the positioning openings when the rotor core is placed in the injection mold, thus creating a predetermined position of the rotor core within the mold. This allows the positioning openings to be used twice, simplifying the handling of the rotor core.

[0024] According to an advantageous embodiment, it can be provided that the rotor shaft and optionally also an axial bearing are inserted into the injection mold, so that the housing pot can be injection molded onto the rotor core and simultaneously onto the rotor shaft and optionally also onto the axial bearing.

[0025] In particular, the housing pot may be designed to have several axial through-openings extending from the side facing the housing cover to the axial bearing. The injection mold used to manufacture or overmold the housing pot may also have additional positioning pins that position the axial bearing in the injection mold relative to the rotor core and / or the rotor shaft. Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0026] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention as defined by the claims. Components of a higher-level unit, such as a device, apparatus, or arrangement, mentioned above and those to be mentioned below, which are designated separately, can form separate parts or components of this unit or be integral areas or sections of this unit, even if this is depicted differently in the drawings. Thus, the rotor, electric motor, hydraulic pump, and method according to the invention can each have features that are disclosed in connection with the rotor, electric motor, hydraulic pump, or method, respectively.

[0027] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0028] They show, schematically, Fig. 1 an axial section of a hydraulic pump in the area of ​​a rotor of an electric motor, Fig. 2 an enlarged detail II from Fig. 1 in the area of ​​a core housing with housing pot and housing cover, Fig. 3 a view as in Fig. 2, however, with the case cover omitted, Fig. 4 a view like in Fig. 2, but only of the case cover, Fig. 5 A sectioned isometric view of the rotor without the housing cover, Fig. 6 a longitudinal section of a rotor core of the rotor.

[0029] Accordingly Fig. The assembly comprises a hydraulic pump 1 and a pumping device 2 for conveying a fluid. The pumping device 2 can, for example, be designed in the form of an impeller. The hydraulic pump 1 also includes an electric motor 3, which is configured to drive the pumping device 2. The electric motor 3 has a stator 4 and a rotor 5, which is rotatable relative to the stator 4 about an axis of rotation 6. The axis of rotation 6 defines a circumferential direction U of the rotor 5, which rotates around the axis of rotation 6 and which is in the Fig. The double arrow indicates the positions of the rotors 1 to 6. The axis of rotation 6 also defines an axial direction of the rotor 5, which extends parallel to the axis of rotation 6. Furthermore, the axis of rotation 6 defines a radial direction of the rotor 5, which extends transversely to the axial direction and is, in particular, perpendicular to the axis of rotation 6.

[0030] The electric motor 3 is configured as an internal rotor, such that the rotor 5 is arranged coaxially within the stator 4. The electric motor 4 can further be configured as a wet rotor, such that the rotor 5 is directly exposed to a liquid, preferably the liquid pumped by means of the pumping device 2.

[0031] The rotor 5 comprises a rotor shaft 7 extending coaxially to the axis of rotation 6. The rotor shaft 7 is configured as a hollow shaft, allowing fluid, particularly for cooling the electric motor 3, to flow through it. The rotor 5 has an annular rotor core 8 through which the rotor shaft 7 extends coaxially. This positions the rotor core 8 concentrically to the rotor shaft 7. The rotor core 8 comprises a laminated core 9 and several permanent magnets 10 distributed around its circumference U. The laminated core 9 consists of a plurality of individual laminations 45, which are only connected in the Fig. 5 and Fig. 6 are indicated by several parallel lines. The sheets 45 are stacked axially against each other or on top of each other. The rotor 5 also has an annular core housing 11, which is made of plastic and through which the rotor shaft 7 extends coaxially. This means that the core housing 11 is arranged concentrically to the rotor shaft 7. The core housing 11 is rotationally fixed to the rotor shaft 7 and contains an annular receiving space 12 in which the rotor core 8 is rotationally fixed. Due to the rotationally fixed arrangement of the rotor core 8 in the core housing 11 and the rotationally fixed arrangement of the core housing 11 on the rotor shaft 7, the rotor core 8 is ultimately also indirectly rotationally fixed to the rotor shaft 7 via the core housing 11.

[0032] The core housing 11 comprises an annular housing pot 13 and an annular housing cover 14. The housing pot 13 defines the receiving space 12 radially outwards, radially inwards, and axially on the one hand, here downwards, i.e., in an axial direction away from the housing cover 14. The housing cover 14 defines the receiving space 12 axially on the other hand, here upwards, i.e., axially opposite to the housing pot 13. In the rotor 5 presented here, the housing pot 13 is injection-molded onto the rotor core 8. The injection molding process is configured such that the housing pot 13 has an inner collar 16 at an axial end 15 facing the housing cover 14, which radially overlaps the rotor core 8, and / or an outer collar 17, which radially overlaps the rotor core 8. In the preferred example shown here, the housing pot 13 has both the inner collar 16 and the outer collar 17.The inner collar 16 and / or the outer collar 17 overlaps the rotor core 8 radially and covers the rotor core 8 axially in the area of ​​the overlap and lies axially against the rotor core 8 in the area of ​​the overlap.

[0033] The housing pot 13 thus rests axially on the first end face 20 of the sheet metal stack 9 by means of the inner collar 16 and the outer collar 17 and axially on the other hand on a second end face 46 of the sheet metal stack 9, which is axially turned away from the first end face 20.

[0034] The rotor core 8 has a radially outer core surface 18, which faces away from the rotor shaft 7, and a radially inner core surface 19, which faces the rotor shaft 7. In the enlarged illustrations of the Fig. 2 and Fig. Figure 3 shows that the outer collar 17 overlaps the rotor core 8 radially inwards on the core's outer surface 18. The inner collar 16 overlaps the rotor core 8 radially outwards on the core's inner surface 19. The inner collar 16 and the outer collar 17 are arranged on the housing pot 13 such that they are radially spaced apart from each other. This allows an annular clearance 21 to be formed on an axial first end face 20 of the rotor core 8 or the sheet metal bundle 9 facing the housing cover 14. This clearance is not radially overlapped by the plastic of the housing pot 13, nor is it axially covered by the plastic of the housing pot 13. Fig. 2 and Fig. Figure 3 clearly shows how the inner collar 16 radially overlaps the rotor core 8 outwards, thereby axially covering the inner surface 19 of the core in the circumferential direction U. Furthermore, it is evident in the Fig. 2 and Fig. 3. It can be seen how the outer collar 17 radially overlaps the rotor core 8 inwards and axially covers it there in the circumferential direction U along the outer surface 18 of the core. Fig. 2 and Fig. Figure 3 also shows that the housing pot 13 is injection-molded onto the rotor core 8 in such a way that the outer collar 17 radially overlaps the permanent magnets 10, preferably completely, and also axially contacts and covers them. This provides additional fixation of the permanent magnets 10 within the laminated core 9. Furthermore, it protects the permanent magnets 10 from contact with liquids that may form in the receiving chamber 12, for example, through condensation or leakage between the housing pot 13 and the housing cover 14.

[0035] The sheet metal package 9 exhibits, according to the Fig. 5 and Fig. 6 several positioning openings 22, which are arranged distributed in the circumferential direction U. The positioning openings 22 are open at the first end face 20 and extend axially through at least two sheets 45. The positioning openings 22 serve to magnetize the permanent magnets 10 by means of a Fig. 6. Magnetizing tool 48. For example, the magnetizing tool 48 can have several positioning pins 49, each of which engages axially into one of the positioning openings 22 to align the rotor core 8 relative to the magnetizing tool 48 in a predetermined relative position. It is also conceivable that the magnetizing tool 48 has several magnetizing probes 50, each of which engages axially into one of the positioning openings 22 for magnetization.

[0036] In the longitudinal section of the Fig. Only one such positioning opening 22 is visible in Figure 6. Of the positioning openings 22, the following are shown in the Fig. 2 and Fig. 3 each only indicated with a broken line.

[0037] The positioning openings 22 are preferably open only at the first end face 20 and extend axially only through some of the sheets 45, i.e., not through all of the sheets 45. In the example of the Fig. 6. The positioning openings 22 extend only through approximately 20% of the laminations 45 that adjoin the first end face 20. Preferably, the positioning openings 22 are arranged radially further inward on the lamination stack 9 than the permanent magnets 10. Preferably, there are the same number of positioning openings 22 as permanent magnets 10. For example, six permanent magnets 10 and six positioning openings 22 can be provided. Preferably, the positioning openings 22 are arranged centrally between two adjacent permanent magnets 10 in the circumferential direction U and offset radially inward from them.

[0038] The housing pot 13 is preferably injection-molded onto the rotor core 8 in such a way that the positioning openings 22 on the first end face 20 are accessible for the magnetizing tool 48 when the housing cover 14 is missing, i.e., they are open or remain open, i.e., they are not covered by the housing pot 13.

[0039] The laminated core 9 preferably has several magnet receiving openings 47, which extend axially through several of the laminations 45 within the laminated core 9 and are spaced radially from the radial outer core surface 18 and radially from the inner core surface 19. The magnet receiving openings 47 are preferably at least partially radially overlapped and axially covered by at least one of the laminations 45 at the first end face 20 of the laminated core 9. This is evident in Fig. 5 a partial overlap or partial covering by the sheet metal 45, which forms the first end face 20. Optionally, it can be provided that the magnet receiving openings 47 on a second end face 46 of the sheet metal assembly 9, facing away from the housing cover 14 or from the first end face 20, are at least partially radially overlapped and axially covered by at least one of the sheets 45. For example, the sheet metal 45, which forms the second end face 46, can be continuous or closed in the area of ​​the magnet receiving openings 47 and thereby close the magnet receiving openings 47 on the second end face 46.

[0040] How Fig. As can be seen from Figure 6, the positioning openings 22 are axially shorter than the magnet receiving openings 47. Preferably, the positioning openings 22 are axially at most half the size, and in particular at most one quarter the size, of the magnet receiving openings 47. While the magnet receiving openings 47 extend axially through at least 95% of the laminated core 9, the positioning openings 22 extend axially through at most 50%, and preferably at most 25%, of the laminated core 9.

[0041] According to the Fig. 2 and Fig. The housing pot 13 has two annular weld zones, namely an inner weld zone 23 and an outer weld zone 24, which are radially spaced apart. The housing cover 14 is welded to the housing pot 13 in the two weld zones 23 and 24. The inner weld zone 23 is formed on the inner collar 16, while the outer weld zone 24 is formed on the outer collar 17. The inner weld zone 23 has an axially projecting, annular circumferential inner projection 25. The outer weld zone 24 has an axially projecting, annular circumferential outer projection 26. The projections 25 and 26 project axially towards the housing cover 14. The inner projection 25 has a radially outwardly sloping outer flank 27. The outer projection 26 has a radially inwardly sloping inner flank 28.

[0042] According to the Fig. 2 and Fig. 4. The housing cover 14 has an annular circumferential inner weld groove 30 on an axial inner surface 29 facing the receiving chamber 12, into which the inner projection 25 projects axially to create an inner weld 31. The housing cover 14 also has an annular circumferential outer weld groove 32 on the inner surface 29, into which the outer projection 26 projects axially to create an outer weld 33. The welds 31, 33 are in the Fig. 1 and Fig. 2 is designated, but not described in more detail. Rather, in the Fig. Figures 1 to 3 show the projections 25, 26 in their state before the welding joints 31, 33 are formed. During the welding joints 31, 33, the projections 25, 26 melt at least partially, thereby bonding to the plastic of the housing cover 14. The melting begins in the respective contact zone where the tapered projections 25, 26 are in contact with the housing cover 14 within the weld grooves 30, 32. Molten plastic can flow along the outer flank 27 and partially or completely fill the inner weld groove 30. Likewise, molten plastic can flow along the inner flank 28 and more or less fill the outer weld groove 32.

[0043] According to the Fig. 2 and Fig. 4. The housing cover 14 can have an annular circumferential recess 34 on its inner surface 29 radially between the two weld grooves 30, 32, which creates a cavity 35 in the receiving space 12. The cavity 35 can be used for a leak test of the core housing 11. It also provides an additional escape volume for molten plastic that may escape from the weld grooves 30, 32 when the housing cover 14 is welded to the housing pot 13.

[0044] To facilitate ultrasonic welding of the housing cover 14 to the housing pot 13, the housing cover 14 can be welded on an axial outer surface 36 facing away from the receiving chamber 12 according to the Fig. 1, Fig. 2 and Fig. 4 should be designed in a similar way. This allows a sonotrode (not shown here) to be placed over a large area on the housing cover 14.

[0045] According to the Fig. 1 to 3 the housing pot 13 has an annular inner shell 37, an annular outer shell 38 and an annular disc-shaped housing base 39, which is only in Fig. 1 is recognizable. During injection molding of the housing pot 13, the inner shell 37, the outer shell 38, and the housing base 39 are manufactured simultaneously. The inner shell 37 is rotationally fixed to the rotor shaft 7 and radially delimits the receiving space 12 inwards. The outer shell 38 radially delimits the receiving space 12 outwards. The housing base 39 axially delimits the receiving space 12 relative to the housing cover 14 and connects the inner shell 37 to the outer shell 38. The inner collar 16 is formed on the inner shell 37. The outer collar 17 is formed on the outer shell 38. According to the Fig. In sections 1 to 3, the inner shell 37 can have several pockets 40 distributed circumferentially U. These pockets are axially closed on one side facing away from the housing cover 14 by the housing base 39 and are axially open on one side facing the housing cover 14. The pockets 40 are separated from each other circumferentially U by webs not specified in detail. The pockets 40 reduce the volume to be filled with plastic in the inner shell 37, making it easier and more reliable to manufacture using injection molding. Alternatively, the pockets 40 can also be designed as through-holes that completely penetrate the housing pot 13 axially and are closed on the side facing away from the housing cover 14 by an axial bearing 42, to which the housing pot 13 can be injection-molded.Positioning pins can be passed through these through-openings in the injection mold, with which the axial bearing 42 can be positioned within the injection mold relative to the rotor core 8.

[0046] The housing pot 13 can optionally also be injection-molded onto the rotor shaft 7. For improved positive locking, the rotor shaft 7 can be provided with a suitable positive locking contour 41 on its outer surface. According to the example shown here, this positive locking contour 41 can have a plurality of transverse ribs that extend circumferentially U and follow one another axially. Additionally, longitudinal ribs can also be present, extending axially and following one another in the circumferential direction U. Furthermore, the housing pot 13 can be injection-molded onto an annular axial bearing 42 through which the rotor shaft 7 extends coaxially. This simplifies the connection between the axial bearing 42 and the rotor shaft 7. Thus, when the housing pot 13 is injection-molded onto the rotor core 8, it can simultaneously be injection-molded onto the rotor shaft 7 and optionally also onto the axial bearing 42.Injection points 43, not shown in detail, for injecting the plastic into an injection mold (not shown) for injection molding the housing pot 13, can be conveniently positioned on the housing base 39 on an outer side 44 of the base facing away from the housing cover 14.

[0047] A method for manufacturing the rotor 5 of the type described above assumes that the core housing 11 has the housing pot 13 and the separate housing cover 14.

[0048] In a first step, the rotor core 8, together with the lamination stack 9 and the as yet unmagnetized permanent magnets 10, is prepared and inserted into an injection mold 51. The injection mold 51 is in Fig.Figure 6 is simplified and represented by the structure that also represents the magnetizing tool 48. Optionally, the rotor shaft 7 can also be inserted into the injection mold 51 in this step. Optionally, the axial bearing 42 can also be inserted into the injection mold 51.

[0049] In a subsequent second step, the housing pot 13 is injection-molded onto the rotor core 8, such that the positioning openings 22 on the first end face 20 of the sheet metal bundle 9 remain unobstructed. According to the options mentioned above, the housing pot 13 can also be injection-molded onto the rotor shaft 7 and optionally onto the axial bearing 42.

[0050] In a subsequent third step, the permanent magnets 10 can be magnetized after the housing pot 13 has been injection-molded using the magnetizing tool 48. The positioning pins 49 of the magnetizing tool 48 can be axially inserted into each of the positioning openings 22 to position the rotor core 8 relative to the magnetizing tool 48. Alternatively, the magnetizing probes 50 of the magnetizing tool 48 can be axially inserted into each of the positioning openings 22 to magnetize the permanent magnets 10.

[0051] According to an advantageous embodiment, the injection mold 51 may have several positioning pins 52 which are axially inserted into the positioning openings 22 when the rotor core 8 is inserted into the injection mold 51 and create a predetermined positioning of the rotor core 8 in the injection mold 51. Reference symbol list 1 hydraulic pump 2 Pump unit 3 Electric motor 4 Stator 5 Rotor 6 Rotation axis 7 Rotor shaft 8 rotor core 9 sheet metal package 10 permanent magnets 11 Core casing 12 Recording room 13 Housing pot 14 Case covers 15 axial pot end 16 inner collars 17 Outer collars 18 Core outer side 19 Core inside 20 Front 21 open space 22 Positioning opening 23 inner welding zone 24 outer welding zone 25 inner lead 26 outside lead 27 Outside flank 28 Inner flank 29 Inside of lid 30 inner weld groove 31 internal weld joint 32 outer weld groove 33 external weld joint 34 In-depth study 35 cavity 36 Lid exterior 37 Inner jacket 38 Outer jacket 39 Case base 40 bags 41 Form-fit contour 42 axial bearings 43 Injection point 44 Bottom outside 45 sheet metal 46 Front 47 Magnet receiving opening 48 Magnetizing tool 49 Positioning pin 50 Magnetization probe 51 injection mold 52 Positioning pin U circumferential direction QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 3 913 770 A1 [0002, 0014]

Claims

[1] Rotor (5) for an internal rotor electric motor (3), in particular a hydraulic pump (1), - with a rotor shaft (7) extending coaxially to a rotational axis (6), - with an annular rotor core (8) through which the rotor shaft (7) extends coaxially and which has a laminated core (9) and several permanent magnets (10) distributed in the circumferential direction (U) on and / or in the laminated core (9), - with an annular core housing (11) made of plastic, through which the rotor shaft (7) extends coaxially, which is rotationally fixed to the rotor shaft (7) and which contains an annular receiving space (12) in which the rotor core (8) is arranged, - wherein the sheet metal stack (9) is formed by several axially stacked sheets (45) and has two axially diverging end faces (20, 46), namely a first end face (20) and a second end face (46),characterized by , - that the lamination stack (9) has several positioning openings (22) distributed in the circumferential direction (U), which are open at the first end face (20) and extend axially through at least two laminations (45) and which are configured for magnetizing the permanent magnets (10) by means of a magnetizing tool (48). [2] Rotor (5) according to claim 1, characterized by , - that the positioning openings (22) are only open at the first end face (20) and extend axially only through some of the sheets (45). [3] Rotor (5) according to claim 1 or 2, characterized by , - that the positioning openings (22) on the lamination stack (9) are arranged radially further inwards than the permanent magnets (10). [4] Rotor (5) according to any one of the preceding claims, characterized by , - that there are the same number of positioning openings (22) as permanent magnets (10), (and preferably) - that the positioning openings (22) are arranged in the circumferential direction (U) centrally between two adjacent permanent magnets (10). [5] Rotor (5) according to any one of the preceding claims, characterized by , - that the core housing (11) has an annular housing pot (13) which limits the receiving space (12) radially inside and radially outside as well as axially on one side, and an annular disc-shaped housing cover (14) which limits the receiving space (12) axially on the other side and is rotationally fixed axially connected to the housing pot (13), - that the first end face (20) of the sheet metal package (9) faces the housing cover (14). [6] Rotor (5) according to claim 5, characterized by , - that the housing pot (13) is injection molded onto the rotor core (8) in such a way that the positioning openings (22) on the first end face (20) are accessible for the magnetizing tool before the housing cover (14) is fitted. [7] Rotor (5) according to claim 6, characterized by , - that the housing pot (13) is injection-molded onto the rotor core (8) in such a way that the housing pot (13) rests axially against the second end face (46) of the lamination stack (9) and has an inner collar (16) radially overlapping the lamination stack (9) and axially abutting it on the first end face (20) of the lamination stack (9) and / or an outer collar (17) radially overlapping the lamination stack (9) and axially abutting it. [8] Rotor (5) according to any one of the preceding claims, characterized by , - that the laminated core (9) has several magnet receiving openings (47) in which one of the permanent magnets (10) is arranged, which extend axially through several of the laminations (45) within the laminated core (9) and are spaced radially from a radial core outer surface (18) and radially from a core inner surface (19). [9] Rotor (5) according to claim 8, characterized by , - that the magnet receiving openings (47) on the first end face (20) of the laminated core (9) are at least partially radially overlapped and axially covered by at least one of the laminations (45), and / or - that the magnet receiving openings (47) on the second end face (46) of the sheet metal bundle (9) are at least partially radially overlapped and axially covered by at least one of the sheets (45). [10] Rotor (5) according to claim 8 or 9, characterized by , - that the positioning openings (22) are axially shorter than the magnet receiving openings (47). [11] Rotor (5) according to claim 10, characterized by , - that the positioning openings (22) are axially at most half as long, in particular at most a quarter as long, as the magnet receiving openings (47). [12] Electric motor (3), in particular for a hydraulic pump (1), - with a stator (4), - with a rotor (5) according to one of the preceding claims, - wherein the rotor (5) is rotatably mounted in the stator (4) about the axis of rotation (6). [13] Hydraulic pump (1), - with a pumping device (2), - with an electric motor (3) according to claim 12 for driving the pumping device (2). [14] Method for manufacturing a rotor (5) according to any one of claims 1 to 11, - wherein the core housing (11) has an annular housing pot (13) which limits the receiving space (12) radially inside and radially outside as well as axially on one side, and an annular disk-shaped housing cover (14) facing the first end face (20) of the lamination stack (9), which limits the receiving space (12) axially on the other side and is rotationally fixed and axially fixed to the housing pot (13), - in which the rotor core (8) is provided with the laminated core (9) and the non-magnetized permanent magnets (10) and inserted into an injection mold (51), - in which the housing pot (13) is injection-molded onto the rotor core (8) in such a way that the positioning openings (22) on the first end face (20) of the sheet metal bundle (9) remain free, - in which the permanent magnets (10) are magnetized after the injection molding of the housing pot (13) by means of a magnetizing tool (48), wherein the magnetizing tool (48) has several positioning pins (49) which are axially inserted into each of the positioning openings (22) for positioning the rotor core (8) with respect to the magnetizing tool (48), and / or has several magnetizing probes (50) which are axially inserted into each of the positioning openings (22) for magnetizing the permanent magnets (10). [15] Method according to claim 14, characterized by , - that the injection mold (51) has several positioning pins (52) which are axially inserted into the positioning openings (22) when the rotor core (8) is inserted into the injection mold (51) and create a predetermined positioning of the rotor core (8) in the injection mold (51).

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