ELECTRIC MOTOR

Description

[0001] The present invention relates to an electric motor, in particular for a motor vehicle, according to the preamble of claim 1. Furthermore, the invention relates to an electric fluid pump comprising such an electric motor. Finally, the invention relates to a method for producing such an electric motor.

[0002] A variety of different electric motors are known from the state of the art, which are designed as so-called wet rotors and are sometimes in direct contact with a liquid.

[0003] DE 195 25 704 C1 discloses an encapsulated squirrel-cage rotor for an asynchronous motor as a wet-running motor. The rotor comprises a corrosion-free drive shaft, a laminated core mounted thereon with electrically short-circuited short-circuit bars, and a liquid-tight protective casing surrounding the laminated core, consisting of a peripheral portion and two end plates, each with a central hole. To improve the liquid-tightness of the protective casing with respect to the drive shaft, an annular gap is formed between the drive shaft and the two end plates surrounding the shaft, which are preferably designed as short-circuit plates. A sealing ring body made of non-metallic, elastic material is arranged in said annular gap. The sealing ring body sits in a liquid-tight manner on the one hand on the drive shaft and rests against the corresponding end plate on the other.

[0004] From WO 2009 / 037019 A1, a pump rotor for a canned pump is known, which has a one-piece base body with an impeller base plate and a rotor receiving bush, wherein a rotor unit with rotor magnets is arranged on the rotor receiving bush.

[0005] WO 2013 / 053537 A2 discloses a rotor or stator of an electrical machine, comprising: a rotor axis extending in an axial direction, a base body arranged concentrically around the rotor axis, at least one permanent magnet arranged in a recess of the base body, and a clamping means that fixes the permanent magnet in the recess. Recesses in which the clamping means is arranged are provided on opposite sides of the recess in the base body. Furthermore, a method for mounting a permanent magnet in a previously described rotor or stator, as well as in a motor having a previously described rotor or stator, is known.

[0006] WO 02 / 39565 A1 discloses an armature for an electrical machine, which consists of at least a rotor shaft and at least two sheet-metal laminates, wherein at least one sheet-metal laminate has at least one closed pocket, and at least one magnet is arranged in the closed pocket. The individual sheet-metal laminates are arranged around the rotor shaft, rotated relative to one another, so that, for example, the magnets are alternately arranged in a closed pocket or are exposed. By stacking the individual sheet-metal laminates, the magnets are held firmly on the one hand, while remaining partially exposed on the other, thus reducing magnetic flux losses.

[0007] DE 10 2005 048 731 A1, DE 10 2006 036 392 A1, DE 10 2010 021 595 A1, DE 10 2010 044 453 A1, and WO 2011 / 048581 A2 disclose rotors for electric motors in which permanent magnets are attached to the laminated core by means of holding devices that radially engage in spaces formed in the circumferential direction between adjacent permanent magnets. The holding devices are each designed as a one-piece holding structure that has two outer contours facing away from each other in the circumferential direction on a cohesive, continuous base body. These outer contours interact with the adjacent permanent magnet to fix it to the laminated core.

[0008] A generic electric motor is known from EP 1 788 690 A1. It has an internal rotor that is rotatably mounted about an axis of rotation relative to an external stator. The rotor has a pot-shaped rotor receiving sleeve arranged around a rotor shaft for receiving an armature unit that has a multi-layered laminated core with several permanent magnets. The rotor receiving sleeve is sealed fluid-tight with a cover. The permanent magnets are arranged spaced from one another in the circumferential direction on a radial outer side of the laminated core. Holding devices are arranged in the spaces between adjacent permanent magnets and prevent slipping in the circumferential direction. In the known electric motor, these holding devices are formed integrally on the rotor receiving sleeve.

[0009] Another electric motor is known from US Pat. No. 5,881,448 A, in which the holding devices are integrally formed on the lamination stack. The holding devices are each designed as a longitudinal web, which is supported on a permanent magnet on each side in the circumferential direction.

[0010] US 2012 / 0 187 792 A1 discloses another electric motor in which the holding devices are also integrally formed on the laminated core. In this case, the holding devices each have two holding arms, each of which is supported by a permanent magnet in the circumferential direction.

[0011] Furthermore, rotors for electric motors are known from the documents JP 2010 136514 A, US 5 140 210 A and US 2002 / 162939 A1.

[0012] The present invention addresses the problem of providing an improved or at least a different embodiment for an electric motor of the type described above or for a combination equipped therewith, which is characterized in particular by a reduced installation space requirement and reduced losses in the magnetic flux and, in particular, can be produced cost-effectively due to simple production.

[0013] 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.

[0014] The invention is based on the general idea of ​​designing an electric motor, in particular for a motor vehicle, such that, on the one hand, an armature unit of a rotor is arranged in a fluid-tight manner in a rotor receiving sleeve provided for this purpose, and, on the other hand, permanent magnets of this armature unit, which are arranged spaced apart from one another in the circumferential direction on a radial outer side of a laminated core, are held at least in the circumferential direction by means of first holding devices, which are formed integrally on the laminated core in respective intermediate spaces between adjacent permanent magnets, in order to optimize installation space. For this purpose, the electric motor according to the invention has an internal rotor which is rotatably mounted about an axis of rotation relative to an external stator, wherein the rotor has a pot-shaped rotor receiving sleeve arranged around a rotor shaft for receiving the armature unit.The armature unit features a multilayer laminated core and several permanent magnets. The rotor sleeve is sealed with a fluid-tight cover when assembled.

[0015] A particularly advantageous embodiment is one in which the respective first holding device has two separate holding arms in the respective intermediate space, which are adjacent in the circumferential direction in the same axial plane. Optionally, it can be provided that the two holding arms of the respective holding device are inclined away from each other such that the holding arms are spaced apart at their free ends in the circumferential direction by a greater distance than at their fixed ends, with which they are connected to the laminated core. This simplifies the manufacture of the rotor in particular, since the separate holding arms can be plastically deformed particularly easily, for example, to fix the permanent magnets to the laminated core.

[0016] A further advantageous embodiment is based on a sheet metal stack comprising a plurality of axially adjacent sheets, and proposes that the two retaining arms of the respective retaining device be formed on the same sheet metal. This simplifies the integral design of the retaining arms on the respective sheet metal. For example, the sheets are punched or cut from a sheet metal strip. Advantageously, several sheets each have such retaining arms integrally formed thereon. Preferably, all or substantially all sheets of the sheet metal stack are equipped with the retaining arms integrally formed thereon.

[0017] In In an advantageous embodiment of the electric motor according to the invention, such a first holding device has holding arms on both sides in the circumferential direction, which are inclined in the direction of the permanent magnets adjacent thereto in the circumferential direction in such a way that the permanent magnets are held radially on the laminated core in a form-fitting manner. The permanent magnets, which are arranged between the first holding devices on the laminated core, have a complementary inclination to the inclination of the holding arms at their longitudinal ends in the circumferential direction, so that the permanent magnets fit into the spaces provided for them between the first holding devices.Furthermore, the permanent magnets are shaped such that the respective longitudinal ends have bevels in the circumferential direction, which have a degree of inclination selected such that a radially inner circumferential contour of the respective permanent magnet is larger than a radially outer circumferential contour of the respective permanent magnet. This means that the previously described design of the permanent magnets creates a positive connection between the permanent magnets and the first holding devices arranged integrally on the laminated core, resulting in a radial fixation of the permanent magnets to the laminated core.

[0018] In a preferred embodiment, the laminated core of the armature unit has an axial groove-like recess in the region of the first holding device, particularly preferably in the region of the holding arms. The groove-like recess is useful when the holding arms of a first holding device undergo elastic or plastic movement upon insertion of the permanent magnets due to a surface displacement of the permanent magnets. The same applies if the holding arms are preloaded toward the permanent magnets and are deformed against the preload upon insertion of the permanent magnets.

[0019] In this case, an embodiment is preferred in which each of the above-mentioned holding arms of the respective holding device is assigned such a groove-like, axial recess, which is located on a side of the respective holding arm in the laminated core facing the respective adjacent permanent magnet.

[0020] In a further advantageous embodiment, such a holding arm of the first holding device additionally has a locking lug on a longitudinal end facing away from the laminated core, which engages over such a permanent magnet in the circumferential direction. The locking lug encloses the permanent magnet at least partially on its radial outer side and thus effects radial fixation of the permanent magnet as well as fixation in the circumferential direction. It is preferred that the combination of the first holding device with holding arms and locking lugs is also preloaded in the circumferential direction against the permanent magnets. The respective locking lug can be formed on the free end of the respective holding arm mentioned above.

[0021] According to a further development, radially inwardly projecting projections are formed on an inner circumferential surface of an outer wall of the rotor receiving sleeve, which projections press at least one of the locking lugs radially inward against the respective permanent magnet. In addition to improving the radial pressure of the permanent magnets against the laminated core, the projections also ensure that the permanent magnets are fixed to the laminated core by the holding devices or their holding arms or their locking lugs.

[0022] A preferred embodiment is one in which a radially outer end of the respective holding device forms the radially outermost outer contour of the sheet metal package. This radially outer end of the respective holding device can be formed by the respective aforementioned locking lug or by the free ends of the aforementioned holding arms.

[0023] In In an advantageous embodiment, the permanent magnets have steps on both sides, in the circumferential direction on the longitudinal sides facing the first holding device, at which the locking lugs of the first holding device engage with the permanent magnets. The advantage of this embodiment is that the required installation space can be reduced compared to the alternative with the encompassing locking lugs, since the locking lugs do not engage over the respective permanent magnets on their radial outer side, but rather at the step, for example, arranged centrally.

[0024] In In an advantageous embodiment of the inventive concept, the cover has wedge-shaped retaining elements on an outer edge in the circumferential direction, which engage in an annular space between the permanent magnets and an outer wall of the rotor receiving sleeve and radially wedge the permanent magnets. It is preferred that in this embodiment, a circumferentially wedge-shaped retaining contour is provided on a side of the permanent magnet opposite the cover, in the region of a base of the rotor receiving sleeve, and is also arranged in the annular space between the permanent magnets and the outer wall of the rotor receiving sleeve, so that the permanent magnets are equally radially wedged on both sides on the axial longitudinal sides.

[0025] A further embodiment provides for at least one second holding device to protrude from an inner surface of the outer wall of the rotor receiving sleeve, which clamps at least one of the permanent magnets radially between the laminated core and the outer wall. Preferably, the rotor receiving sleeve has a plurality of second holding devices, so that all permanent magnets are pressed against the laminated core by at least one such second holding device.

[0026] In a preferred embodiment, the second holding device is formed as a bead-like thickening, and at least one such permanent magnet is pressed radially against the laminated core by such a bead-like thickening. Particularly preferably, such a permanent magnet is pressed against the laminated core by several such bead-like thickenings.

[0027] A further advantageous embodiment of the previously described variant with a second holding device provides that the second holding device is formed from two inclined holding arms facing each other. The holding arms of the second holding device act both radially and circumferentially against the permanent magnets, pressing them radially against the laminated core and securing the permanent magnets in the circumferential direction.

[0028] The second holding device advantageously extends at least partially beveled in the outer wall, toward an open longitudinal end of the pot-shaped rotor receiving sleeve. In other words, in the region of the opening of the rotor receiving sleeve, the second holding device is at least partially inclined over an axial longitudinal section to facilitate the insertion of the permanent magnets.

[0029] In an advantageous embodiment, the rotor receiving sleeve is formed as a plastic injection-molded part. The cover for closing the rotor receiving sleeve is also expediently manufactured as a plastic injection-molded part. Preferably, the rotor receiving sleeve is molded directly onto the rotor shaft or directly onto a bearing bushing designed to accommodate such a rotor shaft.

[0030] In an advantageous development, the rotor receiving sleeve has an annular step on its inner wall on a side facing the opening, which forms a recess open to the cover and the rotor shaft or bearing bush. This recess prevents the cover from sticking to the rotor shaft or bearing bush during a manufacturing process. Furthermore, the recess can serve as a collecting space for excess material from the manufacturing process.

[0031] According to the invention, the cover for the rotor receiving sleeve is arranged radially spaced from the rotor shaft or the bearing bush. This radial spacing is useful in that, in a manufacturing process in which the cover is applied downstream to the rotor receiving sleeve, axially free movement for connecting the two components together facilitates the manufacturing step.

[0032] It can be expediently provided that the rotor receiving sleeve has a tapered collar on a side facing the cover, on its inner and outer walls, which is shaped in such a way that a subsequent manufacturing step is positively influenced by the shape. For example, during ultrasonic welding, the tapered collar provides improved energy transfer to the areas to be welded.

[0033] The cover is expediently provided for fluid-tight sealing of an armature receiving space arranged in the rotor receiving sleeve. The cover is preferably firmly welded to the rotor receiving sleeve using an ultrasonic welding process. Within the scope of the invention, it is also conceivable for the cover to be attached to the rotor receiving sleeve using a rotational friction welding process or a laser welding process. Furthermore, it is possible to injection-mold the cover onto the rotor receiving sleeve accordingly.

[0034] The invention further provides that the cover is designed as a pump impeller for pumping a liquid. This makes it particularly easy to use the electric motor presented here to manufacture a compact liquid pump.

[0035] In a method according to the invention for manufacturing the above-described electric motor, the laminated core is pushed or inserted axially into the armature receiving space of the rotor receiving sleeve. Subsequently, at least one such permanent magnet is pushed axially into the area between the first holding devices of the laminated core and the outer wall of the rotor receiving sleeve. Furthermore, the rotor receiving sleeve is sealed fluid-tight by welding or spraying on the cover.

[0036] Furthermore, the method according to the invention for manufacturing the above-described electric motor includes an additional method step, which involves welding a pump impeller, separate from the cover, to the rotor receiving sleeve by means of ultrasonic welding or laser beam welding. In this case, the rotor receiving sleeve forms a hermetic capsule that surrounds the armature unit and equally affects both the rotor receiving sleeve and the cover. The cover itself thus forms the pump impeller or is designed as a pump impeller.

[0037] An electric liquid pump according to the invention for conveying a liquid comprises a pump impeller which, when rotated, conveys the liquid, and an electric motor of the type described above which is drivingly connected to the pump impeller for rotatingly driving the pump impeller.

[0038] The cover is designed as a pump impeller and is directly connected to the rotor in a rotationally fixed manner, particularly by ultrasonic welding. The pump impeller thus rotates synchronously with the rotor around its axis of rotation.

[0039] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

[0040] Preferred embodiments are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0041] They show, schematically, Fig. 1 is an isometric view of an encapsulated rotor of an electric motor not according to the invention, wherein the rotor is arranged on a rotor shaft formed as a hollow shaft, Fig. 2 is a cross-sectional view of an electric motor with an internal rotor and an external stator, Fig. 3 is a longitudinal section view of Fig. 1 with a rotor receiving sleeve arranged on a rotor shaft, Fig. 4 a detailed view IV from Fig. 3 in the area of ​​a cover that closes a rotor receiving sleeve, Fig. 5 a cross-sectional view of the rotor from Fig. 3 according to section line VV, Fig. 6 a detailed view VI from Fig. 5 in the area of ​​a laminated core and permanent magnets arranged thereon by means of a first holding device, Fig. 7 the view from Fig. 6 in an advantageous embodiment variant with a different first holding device, Fig. 8 a detailed view VIII from Fig. 7 in the area of ​​the first holding device, Fig. 9 the view from the Fig. 6 and 7 in a further advantageous embodiment with stepped permanent magnets and a different first holding device, Fig. 10 an isometric representation of a rotor receiving sleeve, Fig. 11 a detailed view of an advantageous embodiment with a different second holding device, Fig. 12 an isometric representation of an embodiment of a cover for closing a rotor receiving sleeve with wedge-shaped holding elements, Fig. 13 a longitudinal sectional representation of an embodiment of a rotor receiving sleeve with a cover made of Fig. 12 , Fig. 14 a detailed view as in Fig. 8 , but in another embodiment, Fig. 15 a longitudinal section as in Fig. 13 , but in an embodiment according to the invention.

[0042] Fig. 1 shows an isometric representation of an internal rotor 3 of an electric motor 1, which is arranged on a rotor shaft 6 shaped as a hollow shaft. The rotor 3 is rotatably mounted about an axis of rotation 5 relative to an external stator 4 in the circumferential direction 12. The rotor shaft 6 is operatively connected to the rotor 3 as such. A rotor receiving sleeve 7 encloses the rotor shaft 6 at least partially over an axial longitudinal section. Instead of the rotor shaft 6, it is also conceivable for a bearing bush 55 for receiving such a rotor shaft 6 to be overmolded by a rotor receiving sleeve 7. In the further course, such a bearing bush 55 can be used instead of the rotor shaft 6.

[0043] In the present context, the rotational axis 5 defines the longitudinal axis 52 of the rotor 3, which accordingly extends parallel to the rotational axis 5. The radial direction is generally perpendicular to the longitudinal axis and only specifically perpendicular to the rotational axis 5. The circumferential direction, which in some of the figures is indicated by a double arrow and designated by 12, revolves around the rotational axis 5.

[0044] Fig. 2 shows a cross-sectional view of an electric motor 1, in particular for a motor vehicle 2, with an internal rotor 3 and an external stator 4, wherein the stator 4 is fixedly mounted and the rotor 3 is rotatably mounted in the circumferential direction 12 about the rotation axis 5 on the rotor shaft 6. Furthermore, the schematically shown electric motor 1 can be a component of an electrical machine 35, not otherwise shown.

[0045] Fig. 3 shows a longitudinal section of Fig. 1 with a rotor receiving sleeve 7 arranged on a rotor shaft 6. The rotor receiving sleeve 7 is pot-shaped and has an inner wall 25 which is in direct contact with the rotor shaft 6. One longitudinal end of the rotor receiving sleeve 7 is closed with a base 27. The base 27 connects the inner wall 25 to an outer wall 24 of the rotor receiving sleeve 7. The base 27 can in particular be produced integrally with the inner wall 25 and the outer wall 24, e.g. by injection molding. Another longitudinal end of the rotor receiving sleeve 7 has an annular opening 26 which is provided for the insertion of an armature unit 8. The opening 26 of the rotor receiving sleeve 7 can be closed in a fluid-tight manner with a cover 11 after the armature unit 8 has been inserted. The rotor receiving sleeve 7 encloses an armature receiving space 36 which is provided for the armature unit 8.

[0046] Fig. 4 shows a detailed view IV from Fig. 3 in the region of a cover 11 which closes a rotor receiving sleeve 7. The inner wall 25 of the rotor receiving sleeve 7 has, on a side facing the opening 26, an annular step 32. An open recess 33 resulting from the annular step 32 can extend in the longitudinal axial direction over a longitudinal section 37. In the radial direction, a first radial gap 38 of the annular step 32 or the recess 33 can extend over, for example, half the material thickness of the inner wall 25 of the rotor receiving sleeve 7. The cover 11 is also arranged radially spaced from the rotor shaft 6 by a second radial gap 39. Furthermore, the cover 11 can also have an axial play 40 on the inner wall 25 and the outer wall 24 of the rotor receiving sleeve 7 in the direction of the cover 11.

[0047] Fig. 5 shows a cross-sectional view of the rotor 3 from Fig. 3 according to section line VV. The rotor shaft 6 can have at least one notch 41 on an otherwise cylindrical outer surface to achieve a positive connection with the rotor receiving sleeve 7. By injection molding the rotor receiving sleeve 7 onto the rotor shaft 6, the rotor shaft 6 is in direct and positive contact with the inner wall 25 of the rotor receiving sleeve 7 entirely in the circumferential direction 12. The positive connection between the rotor shaft 6 and the rotor receiving sleeve 7 serves to transmit torque, whereby any configuration for positive or frictional torque transmission is protected within the scope of the invention. The inner wall 25 of the rotor receiving sleeve 7 can be designed as a polygon 42 in cross-sectional profile on a side facing the outer wall 24 of the rotor receiving sleeve 7.A subsequently inserted laminated core 9 has a contour complementary to the polygon 42, so that here too a positive connection is established between the laminated core 9 and the rotor receiving sleeve 7. The laminated core 9, which can be subsequently pushed into the rotor receiving sleeve 7, forms an armature unit 8 together with permanent magnets 10 arranged on a radial outer side 13 of the laminated core 9. In the exemplary embodiment shown, the armature unit 8 has a total of eight permanent magnets 10, which are held by first holding devices 14, each of which is arranged integrally on the laminated core 9 in a space 43 between adjacent permanent magnets 10. The permanent magnets 10 are thus arranged radially between the laminated core 9 and the outer wall 24 of the rotor receiving sleeve 7. The laminated core 9 consists in the usual way of a plurality of separate sheets 53, which lie on top of one another in the axial direction 52.For this purpose, identical sheets 53 are used. They can be loosely attached to one another and axially clamped together with appropriate anchors. They can also be glued or soldered together.

[0048] Fig. 6 shows a detailed view VI of the rotor 3 from Fig. 5 in the area of ​​a laminated core 9 and permanent magnets 10 arranged thereon by means of the first holding device 14. The respective holding device 14 has within the same axial plane, which here is defined by the sectional plane of the Fig. 6 , has two separate holding arms 15. In the preferred example, the two holding arms 15 of the respective holding device 14 are clearly inclined away from one another. This inclination is selected such that the holding arms 15 are spaced apart at their radially outer free ends 50 in the circumferential direction 12 by a greater distance than at their radially inner fixed ends 51, with which they are connected to the laminated core 9. Furthermore, it is provided here that the two holding arms 15 of the respective holding device 14 are formed on the same sheet 53. Practically, almost every sheet 53 is provided with these holding arms 15. Accordingly, the first holding device 14 can be adjacent in the circumferential direction 12, i.e. on both sides, these separate holding arms 15, which are inclined in the direction of the permanent magnets 10 adjacent thereto in the circumferential direction 12 in such a way that the permanent magnets 10 are held radially on the laminated core 9 in a form-fitting manner.For this purpose, the holding arms 15 each have an angle of inclination α, which is defined by a plane of symmetry 45 of the first holding device 14 and the orientation of the holding arms 15 in the circumferential direction 12. This angle of inclination α essentially also describes a degree of inclination of bevels 18, which are formed correspondingly at the respective longitudinal ends in the circumferential direction 12 of the permanent magnets 10. The bevels 18 at the longitudinal ends of the permanent magnets 10 can thus be designed to be complementary to the angle of inclination α of the holding arms 15 of the first holding device 14. The first holding device 14 or the holding arms 15 on both sides can hold the permanent magnets 10 radially in a fixed position, depending on the design of the angle of inclination α and the degree of inclination of the bevels 18 of the permanent magnets 10.Furthermore, the degree of inclination of the bevels 18 can be selected such that a radially inner circumferential contour 19 of the respective permanent magnet 10 is larger than a radially outer circumferential contour 20 of the respective permanent magnet 10, wherein the degree of inclination of the bevels 18 should correspond to the angle of inclination α of the holding arms 15 of the first holding device 14. The laminated core 9 can have longitudinal axial recesses 16 in the region of the first holding device 14, in particular in the region of the holding arms 15, which can be groove-shaped. These recesses 16 are clearly located on each of the holding arms 15, specifically on a side facing the adjacent permanent magnet 10.

[0049] Fig. 7 shows the detailed view Fig. 6 in an advantageous embodiment with a different first holding device 14. Such a holder arm 15 of the first holding device 14 can have a locking lug 17 on a longitudinal end facing away from the laminated core 9, which engages over a respective permanent magnet 10 of this type in the circumferential direction 12. Such a locking lug 17 can at least partially enclose the permanent magnet 10 on its radial outer side 13 and thus effects a radial fixation of the permanent magnet 10 as well as a fixation in the circumferential direction 12. Expediently, as shown by way of example in the embodiment variant, all holding arms 15 of the first holding device 14 can be equipped with the described locking lugs 17.

[0050] Fig. 8 shows a detailed view VIII from Fig. 7 in the region of a first holding device 14, in which an elastic or plastic movement of the holding arms 15 is indicated. In a first state, before the permanent magnets 10 are inserted into the area provided for this purpose between the holding arms 15 of the first holding device 14, the holding arms 15 have an inclination angle α' that is at least greater than an inclination angle α in a second state, after the permanent magnets 10 are inserted into the area between the holding arms 15. The larger inclination angle α' in the first state is due to a preload of the holding arms 15 of the first holding device 14 in the circumferential direction 12 against the permanent magnets 10.

[0051] Fig. 9 shows the view from the Fig. 6 and the Fig. 7 in a further advantageous embodiment with stepped permanent magnets 10 and a different first holding device 14. The permanent magnets 10 have steps 21 on both sides in the circumferential direction 12, on the long sides facing the first holding device 14 or the holding arms 15, to which rounded locking lugs 17 of the first holding device 14 lock with the permanent magnets 10. The steps 21 on the permanent magnets 10 can, for example, be arranged centrally on the long sides in the circumferential direction 12. The holding arms 15 of the first holding device 14 extend radially, accordingly, only over half the radial width of the permanent magnets 10. The locking lugs 17 can be arranged on a long side of the holding arms 15 facing away from the laminated core 9, and partially overlap the permanent magnets 10 in the circumferential direction 12 and thus hold them both in the circumferential direction 12 and radially.

[0052] Fig. 10 shows an isometric view of the rotor receiving sleeve 7 with a second holding device 29 arranged thereon. The second holding device 29 can be designed as a bead-like thickening 30 that protrudes from an inner circumferential surface 28 of the outer wall 24 of the rotor receiving sleeve 7. The second holding device 29, which in this illustration is designed as a bead-like thickening 30, can have a taper 46, at least partially over an axial longitudinal section, on a side facing the opening 26, which tapers into the outer wall 24 of the rotor receiving sleeve 7. Furthermore, a negative 44 for the notch 41 of the rotor shaft 6 can be seen in the illustration. The two negatives 44 provided, for example, in the embodiment variant represent the area, in particular made of plastic, that can be additionally injection-molded in the area of ​​the notches 41 of the rotor shaft 6.

[0053] Fig. 11 shows a detailed view of an advantageous embodiment of the rotor receiving sleeve 7 with a different second holding device 29. The second holding device 29 shown has two mutually facing, inclined holding arms 31, which are in contact with the permanent magnets 10 and clamp them radially. The holding arms 31 of the second holding device 29 are at an angle β to one another, which should be at least greater than 0° and less than 180°. The holding arms 30 of the second holding device 29 extend over a maximum length which is selected such that at least a defined spacing of the holding arms 30 of the second holding device 29 is provided. The first holding device 14 and the second holding device 29 are not connected to one another in the embodiment shown.A direct contact between the first holding device 14 and the second holding device 29, in particular an interaction of the two holding devices 14, 29 for the radial fixation of the permanent magnets 10, is conceivable within the scope of this invention.

[0054] Fig. 12 shows an isometric representation of a variant of a cover 11 designed to close a rotor receiving sleeve 7 with wedge-shaped holding elements 22. For this purpose, the cover 11 can have such wedge-shaped holding elements 22 distributed along an outer edge in the circumferential direction 12, which, when the cover 11 is placed on the rotor receiving sleeve 7, protrude in the direction of this rotor receiving sleeve 7, i.e., axially. The wedge-shaped holding elements 22 taper in the direction of the rotor receiving sleeve 7. In addition, cylindrically shaped spacers 47 can be arranged on the cover 11 in the circumferential direction 12, which protrude in the same direction as the wedge-shaped holding elements 22. The spacers 47 can press the armature unit 8 axially into the rotor receiving sleeve 7 or radially clamp the armature unit 8 by the axial pressure, with the aid of a wedge-shaped holding contour 48 on the bottom 27 of the rotor receiving sleeve 7, which will be explained in more detail later.

[0055] Fig. 13 shows a longitudinal section of a variant of a rotor receiving sleeve 7 with attached cover 11 made of Fig. 12 , which is molded onto a rotor shaft 6. The rotor receiving sleeve 7 can have, in the region of the base 27, on an outer wall 24, a wedge-shaped retaining contour 48 that tapers towards the opening 26 of the rotor receiving sleeve 7. An inserted armature unit 8, which comprises a ring-like laminated core 9 and a plurality of permanent magnets 10, can be axially inserted into the rotor receiving sleeve 7, wherein the permanent magnets 10 are in contact with the wedge-shaped retaining contour 48 and wedged therewith. The previously described cover 11, with arranged wedge-shaped retaining elements 22, wedges the armature unit 8, in particular the permanent magnets 10, on the side of the opening 26 of the rotor receiving sleeve 7.The wedge-shaped holding elements 22 on the cover 11 and the wedge-shaped holding contour 48 on the bottom 27 of the rotor receiving sleeve 7 are both located in a radial area between the permanent magnets 10 and the outer wall 24 of the rotor receiving sleeve 7, which can also be referred to as annular space 23.

[0056] One in Fig. 13 The pump impeller 49, not shown, can be subsequently mounted on the rotor receiving sleeve 7 or firmly connected to the rotor receiving sleeve 7. The electric motor 1 as such, with an attached pump impeller 49, forms an electric liquid pump 34.

[0057] At the Fig. 14 shown embodiment, which otherwise corresponds to the Fig. 8 shown embodiment, radially inwardly projecting projections 54 are formed on the inner circumferential surface 28 of the outer wall 24 of the rotor receiving sleeve 7. These projections 54 are preferably formed integrally on said outer wall 24. These projections 54, which can extend in particular over the entire laminated core 9, press at least one of the locking lugs 17 radially inward against the respective permanent magnet 10. In the example shown, each holding arm 15 or each locking lug 17 is assigned a separate projection 54. In another embodiment, not shown here, a common projection 54 can also be provided, which is assigned to both holding arms 15 or the two associated locking lugs 17 of the respective holding device 14 and presses these together against the two adjacent permanent magnets 10.

[0058] In all embodiments shown here, it can be provided that a radially outer end of the respective holding device 14 forms the radially outermost outer contour of the sheet metal package 9. The radially outer end of the respective holding device 14 is formed here by the free ends 50 of the holding arms 15 or by the locking lugs 17.

[0059] While in Fig. 13 an embodiment is indicated in which a separate pump impeller 49 is mounted on the rotor 3 in a rotationally fixed manner, Fig. 15 an embodiment according to the invention in which the cover 11 itself forms the pump impeller 49 or in which the cover 11 is designed as a pump impeller 49.

[0060] The rotor receiving sleeve 7 contains said armature receiving space 36 for receiving the armature unit 8. This armature receiving space 36 is expediently open on an axial side facing the pump impeller 49, so that the armature unit 8 can be inserted axially into the rotor receiving sleeve 7 on this axial side. To seal it against the pumped liquid 56, the armature receiving space 36 is closed in the assembled state of the rotor 3. For this purpose, the said separate cover 11 can be used, which in the Fig. 13 In the embodiment shown, the pump impeller 49 and the remaining rotor receiving sleeve 7 are separate components. In principle, the pump impeller 49 can be directly and non-rotatably connected to the separate cover 11, which in turn is non-rotatably connected to the rotor receiving sleeve 7.

[0061] Fig. 15 1 shows an embodiment of the invention in which the cover 11 is designed as a pump impeller 49 for conveying a liquid. For this purpose, the pump impeller 49 and the cover 11 can be designed as a single piece. In other words, in this case, the cover 11 is integrally formed on the pump impeller 49. This also means that the pump impeller 49 simultaneously forms the cover 11 as an additional function. In As a result, the pump impeller 49 has a cover section 11'. In Fig. 15 The pump impeller 49 or its cover section 11' thus closes the armature receiving space 36 of the rotor receiving sleeve 7.

[0062] According to the Fig. 3 , 13 and 15The armature receiving space 36 is annular and is bounded radially inward by the preferably cylindrical inner wall 25 and radially outward by the preferably cylindrical outer wall 24. As a result, the armature unit 8 has no contact with the rotor shaft 6.

[0063] Preferably, the rotor receiving sleeve 7 has the base 27 at its axial end facing away from the pump impeller 49, which connects the inner wall 25 to the outer wall 24. This means that the armature receiving space 36 is open on the axial side facing the pump impeller 49, so that the armature unit 8 can be inserted on this axial side. Preferably, it can also be provided that the inner wall 25, outer wall 24, and base 27 are manufactured as a single piece, e.g., as an injection-molded part, and form a monolithic body.

[0064] According to Fig. 15 The pump impeller 49 forming the cover 11 or having the cover section 11' can be attached to the inner wall 25 with an internal weld 57 and to the outer wall 24 with an external weld 58. The external weld 58 seals the armature receiving space 36 from the outside against the fluid 56 surrounding the rotor 3. The internal weld 57 also seals the armature receiving space 36 from the outside against the fluid 56 that can enter the space enclosed by the inner wall 25 along the rotor shaft 6 past bearing sleeves 59, 60.

[0065] According to the embodiment of the invention shown here, Fig. 15 For improved integration of the rotor shaft 6 into the rotor 3, two axially spaced-apart bearing sleeves 59, 60 can be provided. The two bearing sleeves 59, 60 are designed and matched to the rotor shaft 6 and any bearing bushing 61 present in such a way that an annular space 62 is formed radially between the bearing bushing 61 and the rotor shaft 6.

[0066] In the inventive example of Fig. 15 One bearing sleeve 59 is arranged on the bearing bush 61 at a longitudinal end of the bearing bush 61 facing away from the pump impeller 49, while the other bearing sleeve 60 is arranged in or on the pump impeller 49 at an axial distance from the bearing bush 61. This allows the axial length of the rotor 3 with the pump impeller 49 to be reduced.

Claims

1. Electric motor (1), in particular for a motor vehicle (2), comprising: - an internal rotor (3), which is rotatably mounted about a rotation axis (5), relative to an external stator (4), - wherein the rotor (3) has a pot-like rotor receiving sleeve (7) arranged around a rotor shaft (6) for receiving an armature unit (8), which has a multi-layered sheet metal assembly (9) with multiple permanent magnets (10), - wherein the rotor receiving sleeve (7) is closed with a cover (11) in a fluid-tight manner, - wherein the permanent magnets (10) are arranged spaced apart from one another in a peripheral direction (12) at a radial outer side (13) of the sheet metal assembly (9), - wherein first retention devices (14) are arranged in intermediate spaces (43) of adjacent permanent magnets (10) on the sheet metal assembly (9) and prevent slippage in a peripheral direction (12), - wherein the first retention devices (14) are constructed integrally on the sheet metal assembly (9), - wherein the cover (11) for the rotor receiving sleeve (7) is arranged to be radially spaced apart from the rotor shaft (6) or the bearing bush (55), characterized in that, - the cover (11) is formed as a pump running wheel (49) for conveying a liquid.

2. Electric motor (1) according to claim 1, characterized in that, - the respective first retention device (14) has, in the respective intermediate space (43), two separate retention arms (15), which are adjacent in the same axial plane in the peripheral direction (12), - the two retention arms (15) of the respective retention device (14) are inclined away from one another such that the retention arms (15) have a greater distance at their free ends (50) in the peripheral direction (12) than at their fixed ends (51), with which they are connected to the sheet metal assembly (9).

3. Electric motor (1) according to claim 1 or 2, characterized in that, - such a first retention device (14) has, on both sides in a peripheral direction (12), retention arms (15), which are constructed so as to be inclined in the direction of the permanent magnets (10) adjacent thereto in a peripheral direction (12), in that the permanent magnets (10) are radially retained on the sheet metal assembly (9) in a positive-locking manner, and / or - in that the sheet metal assembly (9) has, in the region of the first retention device (14), an axial recess (16), which is constructed in a groove-like manner.

4. Electric motor (1) according to any one of claims 1 to 3, characterized in that, - such a retention arm (15) of the first retention device (14) further has, at the longitudinal end thereof, a catch projection (17), which engages over such a permanent magnet (10) in a peripheral direction (12), and / or - in that a radially outer end of the respective retention device (14) forms the radially outermost external contour of the sheet metal assembly (9), and / or - in that the permanent magnets (10) are formed such that the respective longitudinal ends have inclinations (18) in a peripheral direction (12), wherein the decree of inclination of the inclinations (18) is selected such that a radially internal peripheral contour (19) of the respective permanent magnet (10) is greater than a radially external peripheral contour (20) of the respective permanent magnet (10).

5. Electric motor (1) according to any one of claims 1 to 4, characterized in that, - the permanent magnets (10) each have, on both sides at the longitudinal sides, which face the respective first retention device (14), one step (21) each, at which the respective first retention device (14), in particular its retention arm (15) and / or its catch projection (17), interacts with the permanent magnets (10), and / or - in that the retention arms (15) of the first retention device (14) are pretensioned in a peripheral direction (12) counter to the permanent magnets (10), and / or - an annular space (23) is formed radially between the permanent magnets (10) and an outer wall (24) of the rotor receiving sleeve (7), wherein the cover (11) has, at an outer edge in a peripheral direction (12), distributed wedge-like retention elements (22), which engage in the annular space (23) such that they radially wedge the permanent magnets (10).

6. Electric motor (1) according to any one of claims 1 to 5, characterized in that, - an annular space (23) is formed radially between the permanent magnets (10) and an outer wall (24) of the rotor receiving sleeve (7), - in that at least a second retention device (29) projects radially into the annular space (23) at an inner covering surface (28) of the outer wall (24) of the rotor receiving sleeve (7), which clamps at least one of the permanent magnets (10) radially between the sheet metal assembly (9) and the outer wall (24) of the rotor receiving sleeve (7).

7. Electric motor (1) according to claim 6, characterized in that, - the second retention device (29) is formed as a bead-like thickened portion (30) and in that at least one such permanent magnet (10) is pressed with such a bead-like thickened portion (30) radially against the sheet metal assembly (9), preferably with multiple bead-like thickened portions (30), and / or in that the second retention device (29) has two mutually facing, inclined retention arms (31), which are pretensioned and act both radially and in a peripheral direction (12) counter to the permanent magnets (10), and / or - in that the second retention device (29) at least partially terminates in an inclined manner in an outer wall (24) in the direction of an opening (26) of the pot-like rotor receiving sleeve (7).

8. Electric motor (1) according to any one of claims 1 to 7, characterized in that, - the rotor receiving sleeve (7) and / or the cover (11) is / are constructed as plastic injection-molding components, and / or - in that the rotor receiving sleeve (7) is injection-molded directly on the rotor shaft (6) or in that the rotor receiving sleeve (7) is injection-molded on a bearing bush (55), which is formed to received such a rotor shaft (6), and / or - in that the rotor receiving sleeve (7) has, on an inner wall (25) on a side facing the opening (26), an annular step (32) for providing a recess (33), which is open with respect to the cover (11) and the rotor shaft (6) and / or the bearing bush (55).

9. Electric motor (1) according to any one of claims 1 to 8, characterized in that, - at least with the cover (11) not yet mounted, the inner wall (25) and / or the outer wall (24) of the rotor receiving sleeve (7) taper(s) in an acute manner at a side facing the cover (11), and / or - in that the cover (11) is provided for the fluid-tight closure of an armature receiving space (36) and the cover (11) is welded, in particular, to the rotor receiving sleeve (7), for example by ultrasonic welding, rotational friction welding or laser welding, or is injection-molded thereon.

10. Method for producing the electric motor (1) according to any one of the preceding claims, with the steps of: - inserting the sheet metal assembly (9) in an axial direction into the armature receiving space (36) of the rotor receiving sleeve (7), - inserting the permanent magnets (10) in an axial direction into the region between the first retention devices (14) of the sheet metal assembly (9) and the outer wall (24) of the rotor receiving sleeve (7), - closing the rotor receiving sleeve (7) by welding or injection-molding the cover (11), and - welding a pump running wheel (49) to the rotor receiving sleeve (7) by means of ultrasonic welding or laser beam welding.

11. Liquid pump (34) for pumping a liquid, - with a pump running wheel (49), which, when rotating, conveys the liquid, - with an electric motor (1) according to any one of claims 1 to 9 for rotatably driving the pump running wheel (49).