Rotor, electric motor and hydraulic pump

Abstract

The invention relates to a rotor (5) for an electric motor (3), in particular a hydraulic pump (1), with a rotor shaft (7) extending coaxially to an axis of rotation (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) arranged distributed in the circumferential direction (U) on and / or in the laminated core (9), and 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 chamber (12) in which the rotor core (8) is arranged, wherein the core housing (11) has an annular housing pot (13) which delimits the receiving chamber (12) radially inwards and radially outwards as well as axially on one side, and an annular disk-shaped housing cover (14).which axially limits the receiving space (12) on the other hand and is rotationally fixed and axially fixed to the housing pot (13). The manufacture of the rotor (5) can be simplified by injection molding the housing pot (13) onto the rotor core (8) in such a way that the housing pot (13) has an inner collar (16) radially overlapping the rotor core (8) and / or an outer collar (17) radially overlapping the rotor core (8) at an axial pot end (15) facing the housing cover (14).

Description

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

[0002] A rotor of this type is known from DE 10 2017 203 736 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 core housing comprises an annular housing pot that defines the receiving space radially inwards and outwards, as well as axially, and an annular housing cover that defines the receiving space axially and is rotationally and axially fixed to the receiving pot. In the known rotor, the housing pot is an injection-molded part that can be molded directly onto the rotor shaft, and into which the rotor core is axially inserted. The housing cover can be welded to the housing pot. The known rotor requires a comparatively high level of effort to securely connect the permanent magnets to the lamination stack. Furthermore, the manufacturing of the known rotor is comparatively complex, as a relatively large number of manufacturing steps must be performed sequentially. For example, the permanent magnets must be fixed to the lamination stack. Afterward, the rotor core can be inserted into the previously injection-molded housing pot.Following this, the housing cover can be attached to the housing pot.

[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 therewith, or for a hydraulic pump equipped therewith, which is characterized in particular by simplified manufacturability.

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

[0005] The invention is based on the general concept of injection molding the housing cup onto the rotor core. This results in a housing cup that is, in particular, a single piece. This eliminates the need to insert the rotor core into the housing cup. Simultaneously, the injection molding of the housing cup onto the rotor core can be carried out in such a way that the rotor core is connected to the housing cup in a rotationally and axially fixed manner. Furthermore, the injection molding of the housing cup onto the rotor core can be configured to fix the permanent magnets to the laminated core. Accordingly, the manufacturing of the rotor presented here is significantly simplified.

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

[0007] Specifically, the invention proposes that the housing pot is injection-molded onto the rotor core such that the housing pot has an inner collar and / or an outer collar radially overlapping the rotor core at an axial end facing the housing cover. The overlap of the inner collar and / or the outer collar on the rotor core at least partially covers and encloses the rotor core, thus fixing it to the housing pot by positive locking. In a rotor core configuration where the permanent magnets extend axially to an end face of the laminated core facing the housing cover, the radial overlap of the inner collar and / or the outer collar can also achieve positive locking of the permanent magnets by radially overlapping the respective permanent magnets at their end faces.

[0008] The rotor core has a radially outer core surface and a radially inner core surface. The outer collar overlaps the rotor core radially inwards at the outer core surface and covers it axially there, while the inner collar overlaps the rotor core radially outwards at the inner core surface and covers it axially there. Preferably, the outer collar radially overlaps the rotor core at its end face by at least 10%, more particularly at least 20%, and more particularly at most 35% of the radial extent of the rotor core between the outer core surface and the inner core surface. In particular, the inner collar radially overlaps the rotor core at its end face by at least 10%, more particularly at least 20%, and more particularly at most 35% of the radial extent of the rotor core between the outer core surface and the inner core surface. This improves the connection between the housing pot and the housing cover. Advantageously, both the outer collar and the inner collar are formed on the housing pot.Furthermore, the outer collar and the inner collar are expediently configured so that both radially overlap the rotor core. The outer collar then overlaps the rotor core radially inwards, while the inner collar overlaps the rotor core radially outwards.

[0009] According to an advantageous embodiment, the inner collar and the outer collar are radially spaced apart from each other, so that an annular free area exists on the end face of the rotor core which is not radially overlapped and axially covered by the inner collar or the outer collar.

[0010] In one embodiment, the housing pot can be injection-molded onto the rotor core in such a way that the inner or outer collar radially overlaps the permanent magnets and makes axial contact. This provides additional positive locking of the permanent magnets to the lamination stack. Furthermore, it offers additional protection against corrosion for the permanent magnets, particularly when they are completely radially overlapped and axially covered by the inner or outer collar at their end faces.

[0011] According to an advantageous embodiment, the rotor core can have several circumferentially distributed positioning openings on its axial end face facing the housing cover. During rotor manufacturing, positioning pins of a magnetizing tool can engage axially into these openings to magnetize the permanent magnets and create a predetermined orientation of the rotor core relative to the magnetizing tool. Advantageously, the housing can be injection-molded onto the rotor core in such a way that the positioning openings remain unobstructed. In other words, the radial overlap of the rotor core by the inner and / or outer collar terminates before the positioning openings or eliminates the need for them. This makes it possible to carry out the magnetization of the permanent magnets with high precision after the housing can has been injection-molded onto the rotor core.It is generally preferred that at least one of the positioning openings is arranged radially, and in particular completely, between the outer collar and the inner collar. Furthermore, it is generally possible to optionally use the positioning openings to position and / or hold the rotor core in an injection mold for overmolding the housing shell. For this purpose, corresponding positioning pins of the injection mold can engage in the positioning openings to create a predetermined relative position of the rotor core in the injection mold.

[0012] According to an advantageous embodiment, the housing pot can have two annular weld zones, namely an inner weld zone and an outer weld zone, which are radially spaced apart. The housing cover is welded to the housing pot in both weld zones and is thereby fixed to the housing pot in a rotationally and axially fixed manner. Alternatively, it is also possible to injection-mold the housing cover onto the housing pot after the permanent magnets have been magnetized.

[0013] Welding the housing cover to the housing tub, or to the two welding zones of the housing tub, can be carried out in several different ways. Ultrasonic welding is preferred, in which the housing cover is pressed axially against the welding zones and the housing cover and / or the housing tub, preferably only the housing cover, is excited to ultrasonic vibrations, causing the plastic in the welding zones to heat up until it melts. Alternatively, a laser welding process using a laser beam can be used. In this case, it is particularly conceivable to manufacture the housing cover from a plastic that is transparent to the laser beam, while the housing tub or the welding zones are made of a plastic that is opaque to the laser beam and can be heated by the laser beam.Furthermore, a friction welding process is also conceivable in principle, in which the housing cover is pressed axially against the welding zones and set into rotation around the rotational axis of the rotor, whereby the welding zones are ultimately heated by friction.

[0014] A particularly advantageous configuration is one in which the inner weld zone is formed on the inner collar and / or the outer weld zone is formed on the outer collar. Specifically, the respective weld zone is formed on the side of the inner or outer collar facing away from the rotor core. This gives the inner and outer collars an additional function, ultimately facilitating a compact design and simplified manufacturing. Since the inner or outer collar is configured to radially overlap the rotor core, it is generally possible to form the respective weld zone within the area of ​​radial overlap. For example, the outer weld zone can be formed radially inward from the outer surface of the core. Similarly, the inner weld zone can be formed radially outward from the inner surface of the core. This supports a compact rotor design.

[0015] The inner weld zone can have an axially projecting, annular inner projection. The outer weld zone can have an axially projecting, annular outer projection. Preferably, the inner projection and / or the outer projection point axially towards the housing cover. On an axial inner surface of the cover facing the receiving space, the housing cover can have an annular inner weld groove complementary to the inner projection of the inner weld zone, into which the inner projection of the inner weld zone projects axially to create an inner weld. Additionally or alternatively, the housing cover can have an annular outer weld groove on its inner surface, complementary to the outer projection of the inner weld zone, into which the outer projection of the inner weld zone projects axially to create an outer weld.

[0016] Alternatively or additionally, the housing cover can have an axially projecting, annular inner projection on its inner surface and / or an axially projecting, annular outer projection. The inner weld zone can have an annular inner weld groove complementary to the inner projection of the housing cover, into which the inner projection extends axially to create an inner weld. Additionally or alternatively, the outer weld zone can have an annular outer weld groove complementary to the outer projection of the housing cover, into which the outer projection extends axially to create an outer weld.

[0017] The welding grooves, interacting with the respective protrusions, ensure a predetermined positioning of the housing cover relative to the housing pot and promote a reliable weld. Simultaneously, the welding grooves provide a buffer volume into which the liquefied plastic can escape during the welding process. Advantageously, the welding process is carried out in such a way that the respective protrusion preferably liquefies within its corresponding welding groove.

[0018] A particularly advantageous embodiment is one in which the respective inner projection has a radially outwardly sloping outer flank. Additionally or alternatively, the respective outer projection can have a radially inwardly sloping inner flank. The respective flank causes the projection to taper towards the housing cover, which promotes the melting of the projection in a contact zone where the projection touches the housing cover in the respective weld groove. The orientation of the respective flank determines the direction in which the molten plastic can flow. In the case of the inner projection, the outer flank is oriented such that it slopes radially outwards. Consequently, the molten plastic generated during the welding process flows radially outwards along the outer flank.At the outer projection, the inner flank is oriented radially inwards, so that the molten plastic flows radially inwards during the welding process. In other words, during welding, the molten plastic flows radially outwards at the inner weld zone, away from an inner edge of the housing cover and the housing pot, while the molten material flows radially inwards at the outer weld zone, away from an outer edge of the housing cover and the housing pot. This prevents molten metal from escaping at the transition between the housing pot and the housing cover, both radially outwards and radially inwards, thus creating a clean transition. In particular, this eliminates the need for post-processing to remove any escaping molten metal. Consequently, this measure simplifies the manufacturing process.

[0019] According to an advantageous embodiment, the housing cover can have an annular circumferential recess on its inner surface, radially between the inner and outer weld grooves and / or the inner and outer projections, creating a cavity within the receiving space. This cavity can be used, on the one hand, to collect excess molten metal that escapes from the inner and / or outer weld grooves. However, a particular advantage is that the cavity provided within the receiving space allows a volume of gas to be trapped axially between the housing cover and the end face of the rotor core. This gas volume is of particular importance for leak testing of the housing. In the event of a leak in the inner and / or outer weld joint, the trapped gas can escape and be detected using suitable gas detectors.For example, helium can be used as a gas that is enclosed in the cavity. A helium leak detector can then be used to detect any escape of helium from the cavity during a leak test.

[0020] In another embodiment, the housing cover may be configured as flat on an axial outer surface facing away from the receiving chamber. For this purpose, the housing cover has, in particular, a flat axial outer surface on its axial outer surface, which extends, in particular continuously, in particular uninterrupted, over at least 50%, in particular at least 75%, in particular at least 90% of the axial outer surface, in particular the entire axial outer surface. Due to the flat design of the outer surface of the housing cover, the housing cover is particularly suitable for ultrasonic welding to the housing pot. A sonotrode for transmitting the ultrasonic vibrations to the housing cover can be easily positioned on the flat outer surface, with the flat configuration ensuring high efficiency for energy input during the welding process.Accordingly, the axial outer surface is particularly preferably arranged radially at the level of the respective inner welding zone and / or outer welding zone.

[0021] In one embodiment, the housing pot can have an annular inner shell that is rotationally fixed to the rotor shaft and that radially delimits the receiving space inwards. The housing pot can also have an annular outer shell that radially delimits the receiving space outwards. Furthermore, the housing pot can have an annular disc-shaped base that axially delimits the receiving space and connects the inner shell to the outer shell. The inner collar can be formed on the inner shell, and the outer collar can be formed on the outer shell. This results in a particularly simple design for the housing pot.

[0022] According to an advantageous embodiment, the inner shell can have several circumferentially distributed pockets, which are axially closed on one side by the housing base and axially open on the other. These pockets are located radially on the inner shell between the rotor shaft and the rotor core and can extend to the inner collar in the area of ​​the housing cover. With the aid of these pockets, the inner shell can be dimensioned relatively large radially without mass accumulation occurring within it, which could be detrimental to the injection molding of the housing shell. Increasing the radial distance between the rotor shaft and the rotor core can improve the electrical efficiency of the electric motor equipped with the rotor.

[0023] According to an advantageous embodiment, the housing can also be injection-molded onto the rotor shaft. This eliminates the need to fix the core housing to the rotor shaft. The rotor shaft can have a transversely ribbed and / or longitudinally ribbed outer contour, thereby creating a positive fit between the rotor shaft and the injection-molded housing. The transverse ribs extend in the circumferential direction and create a positive fit in the axial direction. The longitudinal ribs extend parallel to the axis of rotation and create a positive fit in the circumferential direction. This enhances the stability of the rotationally and axially fixed connection between the housing and the rotor shaft.

[0024] The housing base preferably comprises a first housing base section that axially delimits the receiving space and connects the inner shell to the outer shell, and an adjacent second housing base section that is arranged radially between the rotor shaft and the rotor core for connecting the rotor core to the rotor shaft. The first housing base section and the second housing base section are arranged axially offset, with the second housing base section being, in particular, axially further away from the rotor core than the first housing base section.

[0025] Additionally or alternatively, the housing pot can also be injection-molded onto an annular axial bearing through which the rotor shaft extends coaxially. This eliminates the need for separate mounting of the axial bearing, further simplifying rotor manufacturing. The housing pot preferably encloses at least a section of an outer surface, particularly an axial one, that points away from the rotor core. Specifically, the axial bearing has an axial bearing surface on its outer surface for contact with a counter-bearing surface of an axial counter-bearing.

[0026] In particular, the housing pot may be provided with several axial through-openings extending from the side facing the housing cover to the thrust bearing. The injection mold used to manufacture or overmold the housing pot may now have additional positioning pins that position the thrust bearing in the injection mold relative to the rotor core and / or the rotor shaft. These through-openings may be advantageously provided instead of the pockets mentioned above.

[0027] 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 in the stator about the axis of rotation. The electric motor is configured as an internal rotor, 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, to cool the rotor and / or the stator, in particular to cool 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. In preferred embodiments, the rotor can have features mentioned above in connection with the rotor.

[0028] 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, gerotor, or the like. Advantageously, the pumping device can be connected to the rotor shaft in a rotationally fixed manner.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Accordingly Fig. The hydraulic pump 1 comprises a pumping device 2 for conveying a fluid. The pumping device 2 can be configured, for example, as a pumping wheel, an impeller, the inner rotor of a gerotor, or the outer rotor of a gerotor. The hydraulic pump 1 also includes an electric motor 3 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 located in the Fig. 1 to 4 is indicated by a double arrow. 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.

[0034] 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.

[0035] 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 the fluid used to cool 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 with the rotor shaft 7. The rotor core 8 includes a laminated core 9 and several permanent magnets 10 distributed around its circumference U. The laminated core 9 consists of numerous individual laminations, not shown in detail here, stacked axially adjacent to one another. The rotor 5 also has an annular core housing 11 made of plastic, through which the rotor shaft 7 extends coaxially. This positions the core housing 11 concentrically with the rotor shaft 7.The core housing 11 is non-rotatably connected to the rotor shaft 7 and contains an annular receiving chamber 12 in which the rotor core 8 is arranged non-rotatably. Due to the non-rotatable arrangement of the rotor core 8 in the core housing 11 and the non-rotatable arrangement of the core housing 11 on the rotor shaft 7, the rotor core 8 is ultimately also indirectly arranged non-rotatably on the rotor shaft 7 via the core housing 11.

[0036] 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.

[0037] In the enlarged representations of the Fig. 2 and Fig. Figure 3 shows that 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. The outer collar 17 overlaps the rotor core 8 radially inwards at the core outer surface 18. The inner collar 16 overlaps the rotor core 8 radially outwards at the core 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 surface 21 to be formed on an axial end face 20 of the rotor core 8 facing the housing cover 14, which is neither radially overlapped nor 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.

[0038] The rotor core 8 or the laminated core 9 can have several positioning openings 22 distributed circumferentially U on its end face 20 facing the housing cover 14, of which in the Fig. 2 and Fig. 3, each of which is indicated by a dashed line. The positioning openings 22 can be arranged offset in the circumferential direction U relative to the permanent magnets 10, with one such positioning opening 22 being arranged between each pair of permanent magnets 10 adjacent in the circumferential direction U. The positioning openings 22 are designed such that positioning pins of a magnetizing tool (not shown here), configured for magnetizing the permanent magnets 10, can engage axially in the positioning openings 22. This makes it particularly easy to move the rotor core 8 into a predetermined relative position with respect to the magnetizing tool. For this purpose, the positioning openings 22 are axially open at the end face 20 of the rotor core 8 or the lamination stack 9. Advantageously, the housing pot 13 is therefore injection-molded onto the rotor core 8 in such a way that the positioning openings 22 remain unobstructed.In particular, the positioning openings 22 on the front face 20 of the rotor core 8 open into the free area 21.

[0039] 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.

[0040] 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 process, 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 flows along the outer flank 27 and more or less fills the inner weld groove 30. Similarly, molten plastic can flow along the inner flank 28 and more or less fill the outer weld groove 32.

[0041] 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.

[0042] 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.

[0043] 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 closed axially on one side facing away from the housing cover 14 by the housing base 39 and are open axially on one side facing the housing cover 14. The pockets 40 are separated from each other circumferentially U by ribs not specified in detail. The pockets 40 reduce the volume to be filled with plastic in the inner shell 37, thus making it easier and more reliable to manufacture using injection molding.

[0044] 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. 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 axial front face 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 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] DE 10 2017 203 736 A1

[0002]

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 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) which limits the receiving space (12) axially on the other side and is rotationally fixed axially connected to the housing pot (13), characterized by , - that the housing pot (13) is injection-molded onto the rotor core (8) in such a way that the housing pot (13) has an inner collar (16) radially overlapping the rotor core (8) and / or an outer collar (17) radially overlapping the rotor core (8) at an axial pot end (15) facing the housing cover (14). [2] Rotor (5) according to claim 1, characterized by , - that the housing pot (13) has both the inner collar (16) and the outer collar (17) which are radially spaced apart from each other. [3] Rotor (5) according to any one of the preceding claims, characterized by , - that the housing pot (13) is injection molded onto the rotor core (8) in such a way that the inner collar (16) or the outer collar (17) radially overlaps the permanent magnets (10) and axially contacts them. [4] Rotor (5) according to any one of the preceding claims, characterized by , - that the rotor core (8) has several circumferentially distributed positioning openings (22) on its axial end face (20) facing the housing cover (14), into which positioning pins of a magnetizing tool configured for magnetizing the permanent magnets (10) and / or an injection mold configured for injection molding the housing pot (13) onto the rotor core (8) can axially engage, - that the housing pot (13) is injection molded onto the rotor core (8) in such a way that the positioning openings (22) remain free. [5] Rotor (5) according to any one of the preceding claims, characterized by , - that 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, - that the housing cover (14) is welded to the housing pot (13) in the two welding zones (23, 24). [6] Rotor (5) according to claim 5, characterized by , - that the inner welding zone (23) is formed on the inner collar (16), - that the outer welding zone (24) is formed on the outer collar (17). [7] Rotor (5) according to claim 5 or 6, characterized by , - that the inner welding zone (23) has an axially projecting, annularly circumferential inner projection (25), - that the outer weld zone (24) has an axially projecting, annularly circumferential outer projection (26), - that the housing cover (14) has an annular circumferential inner weld groove (30) on an axial inner surface (29) facing the receiving space (12), into which the inner projection (25) projects axially to create an inner weld connection (31), - that the housing cover (14) has an annular circumferential outer weld groove (32) on the inside of the cover (29), into which the outer projection (26) projects axially to create an outer weld connection (33). [8] Rotor (5) according to claim 7, characterized by , - that the inner projection (25) has a radially outwardly sloping outer flank (27), - that the outer projection (26) has a radially inwardly sloping inner flank (28). [9] Rotor (8) according to claim 7 or 8, characterized by , - that the housing cover (14) has a ring-shaped circumferential depression (34) on the inside of the cover (29) radially between the inner weld groove (30) and the outer weld groove (32), which creates a cavity (35) in the receiving space (12). [10] Rotor (8) according to any one of the preceding claims, characterized by , - that the housing cover (14) is configured flat on an axial outer surface (36) facing away from the receiving space (12). [11] Rotor (8) according to any one of the preceding claims, characterized by , - that the housing pot (13) has an annular inner shell (38) which is rotationally fixed to the rotor shaft (7) and which radially limits the receiving space (12) inwards, - that the housing pot (13) has an annular outer shell (38) that radially limits the receiving space (12) to the outside, - that the housing pot (13) has an annular disc-shaped housing base (39) which axially limits the receiving space (12) and which connects the inner shell (37) with the outer shell (38), - that the inner collar (16) is formed on the inner coat (37) and / or the outer collar (17) is formed on the outer coat (38). [12] Rotor (5) according to claim 11, characterized by , - that the inner mantle (37) has several pockets (40) distributed in the circumferential direction (U), which are closed axially on one side by the housing base (39) and are open axially on the other side. [13] Rotor (5) according to any one of the preceding claims, characterized by , - that the housing pot (13) is also injection-molded onto the rotor shaft (7), and / or - that the housing pot (13) is also injection-molded onto a ring-shaped axial bearing (42) through which the rotor shaft (7) extends coaxially. [14] 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. [15] Hydraulic pump (1), - with a pumping device (2), - with an electric motor (3) according to claim 14 for driving the pumping device (2).

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