Electric motor

Abstract

The present invention relates to an electric motor (1) comprising at least one housing (3), wherein the housing (3) has a cylindrical section (3a) and at a first end side (1a) a housing base (3b) formed integrally with the cylindrical section (3a), wherein the housing (3) has at least one cover element (15) at a second end side (1b), at least one rotor (4) and at least one stator (5), wherein the rotor (3) has at least one rotor shaft (6), and wherein the rotor shaft (5) is supported by at least one first shaft bearing (7) and at least one second shaft bearing (8). The electric motor (1) is characterized in that the rotor (3) has at least one first support disk (11), the first support disk (11) facing the first end face (1a), and the first support disk (11) is designed to support the rotor (3) against the outer ring (7a) of the first shaft bearing (7) and / or against the housing (3) during axial acceleration along a longitudinal axis (A) of the rotor shaft (5).

Description

[0001] The invention relates to an electric motor comprising at least one housing, at least one rotor, and at least one stator. The housing has a cylindrical section and, at a first end, a housing base formed integrally with the cylindrical section. At a second end, the housing has at least one cover element. The rotor has at least one rotor shaft, which is supported by at least one first shaft bearing and at least one second shaft bearing. The first shaft bearing has at least one outer ring with at least one shoulder that abuts the housing.

[0002] Electric motors are known in a wide variety of designs in the state of the art.

[0003] EP 2 232 678 B1 discloses an electric motor comprising a stator, a rotor, and a circuit carrier. The circuit carrier is arranged in a pot-shaped housing of the electric motor. The housing has a base section and a surrounding receiving section in which the circuit carrier is mounted parallel to the base. The housing can be closed with a housing cover. Bearings, in particular ball bearings, are arranged in the base section and the cover for supporting a motor shaft of the rotor.

[0004] DE 10 2023 122 072 B3 discloses an electric motor comprising a housing, a rotor, and a stator. The rotor has a rotor shaft. The rotor shaft is supported on the housing by a first bearing and a second bearing. The rotor is supported axially via a first support disk and further via a bearing sleeve and its flange against an inner ring of the first bearing.

[0005] In certain applications, particularly in aerospace engineering, electric motors must withstand extreme mechanical stresses. These include, above all, high acceleration and braking forces, such as those that occur when rapidly moving or positioning flaps, rudders, or other controllable components. For these demanding applications, a particularly robust and precise design of the electric motors is required. Solutions known from the prior art often reach their limits in this regard, as the design and manufacturing of such motors is very complex and costly.

[0006] The present invention is therefore based on the objective of providing an electric motor that is advantageously designed for high axial loads, in particular accelerations.

[0007] The aforementioned problem is solved in a generic electric motor with the features of the characterizing part of claim 1, namely in that the rotor has at least one first support disk, that the first support disk faces the first end side, and that the first support disk is designed to support the rotor against the outer ring of the first shaft bearing and / or against the housing, in particular the one-piece formed housing base, when a force, e.g. acceleration, is applied along the rotor axis.

[0008] The stator and rotor are preferably arranged in an interior enclosed by the housing. The housing has at least one cylindrical section and, at a first end face, a housing base formed integrally with the cylindrical section. The cylindrical section preferably extends parallel to a longitudinal axis. In particular, the housing base is thicker than the housing wall in the cylindrical section, preferably at least twice or at least four times as thick. The housing is particularly cup-shaped and formed integrally. For example, the housing is manufactured integrally by a machining process, e.g., milling. At a second end face opposite the first end face, the housing has at least one cover element. The cover element is formed separately and, for example, connected to the cylindrical section, e.g., by welding or bonding.The cover element, for example, has a thickness approximately equal to that of the housing base. However, it is also possible for the cover element to be thicker than the housing base. The electric motor preferably has an outer diameter between 14 mm and 20 mm.

[0009] The stator preferably surrounds the rotor. The rotor shaft is supported by at least one first bearing and at least one second bearing. The first bearing is preferably located at the first end of the electric motor, and the second bearing at the second end. Preferably, the rotor shaft protrudes at the second end, for example, for connection to a gearbox.

[0010] Preferably, at least one permanent magnet is at least partially injection-molded onto the rotor shaft using plastic. Preferably, a plurality of permanent magnets are injection-molded onto the rotor shaft using plastic. The plastic injection molding process serves to positively secure the permanent magnet(s). The injection molding improves mechanical stability at high speeds and protects the permanent magnets from environmental influences such as moisture or vibrations. The permanent magnet is, for example, a neodymium-iron-boron magnet (NdFeB magnet) or a cobalt magnet, in particular a samarium-cobalt magnet.

[0011] The first support disc faces the first end face and thus serves to support the rotor at the first end face. The first support disc is, for example, at least partially, and in particular entirely, made of bronze. The first support disc is preferably designed and arranged such that, when the electric motor accelerates, it distributes a force acting from the rotor onto the outer ring and / or the housing, in particular the housing base, across the surface of the outer ring and / or the housing. For example, the area with which the support disc contacts the rotor is larger than the area with which the support disc contacts the outer ring and / or the housing under load. Preferably, the first support disc contacts the rotor only at its end face. Preferably, the first support disc is designed such that, when a force is applied, it is supported only against the outer ring and / or the housing, in particular the housing base.

[0012] The first support disk is preferably arranged with its inner circumference on a circumferential shoulder at the end face of the rotor. The circumferential shoulder is preferably made of a plastic, in particular the same plastic with which the at least one permanent magnet is connected to the rotor shaft. The first shaft bearing is, for example, arranged directly on the rotor shaft with an inner ring. It is particularly recommended that the first shaft bearing and the second shaft bearing be identical. Alternatively, it is recommended that the first shaft bearing and the second shaft bearing be different.

[0013] The invention offers an advantage over the prior art in that the presence of the support disk enables the electric motor to be designed for very high axial acceleration, i.e., acceleration along the longitudinal axis of the rotor shaft. Furthermore, the fact that the housing base, against which the rotor is at least indirectly supported, is formed integrally with the cylindrical section of the housing results in advantageous structural stability of the motor.

[0014] According to a first embodiment, it has proven advantageous to provide at least one shoulder on the outer ring of the first shaft bearing, and for the shoulder to abut the housing. The shoulder is formed, for example, by a circumferential projection or a circumferential step in the outer ring of the first shaft bearing. In particular, the shoulder is designed as an axial flange shoulder. The first shaft bearing preferably abuts the housing, especially the housing base, with the shoulder in contact with it. Preferably, the first support disc bears against the outer ring, especially the shoulder, and / or the housing, especially the housing base. However, it is also specifically provided that the first support disc bears only against the outer ring.

[0015] According to a further embodiment of the electric motor, it has proven advantageous to have the shoulder rest against the housing on an inner surface facing the rotor. In particular, the housing is provided to have at least one recess, and the shoulder is arranged within this recess. Preferably, the shoulder has an axial depth approximately equal to the depth of the recess. Even more preferably, the shoulder has a slightly shallower depth than the recess. The difference between the depth of the shoulder and the recess is precisely the amount by which the rotor can move during axial acceleration towards the first shaft bearing before the first support disk contacts the outer ring of the first shaft bearing.

[0016] Another embodiment provides that the shoulder rests against the housing base, which is formed integrally with the housing. The housing is preferably cup-shaped, with the rotor shaft passing through the housing base, which is formed integrally with the cylindrical housing wall. The housing base is located at the first end of the electric motor. Preferably, the first shaft bearing is at least partially located in the housing base.

[0017] For example, the housing, in particular the housing base, has at least one recess through which the first shaft bearing passes through the housing. Specifically, the first shaft bearing projects from the housing on the outside, particularly at the first end face. This achieves advantageous stability in the arrangement of the first shaft bearing within the housing. At the first end face, the rotor shaft is arranged essentially flush with the first shaft bearing.

[0018] To keep the rotor longitudinally spaced from the outer ring or the housing when there is no load or acceleration along its longitudinal axis, a further embodiment provides that the rotor is pre-tensioned towards the second shaft bearing or the second end of the electric motor by at least one first spring, for example, a disc spring. The first shaft bearing is supported, at least indirectly, by the housing and / or the first shaft bearing in such a way that the rotor is forced towards the second shaft bearing or the second end. During acceleration that forces the rotor towards the first end, the first spring is further deformed. Preferably, the first spring is supported at the first end of the rotor by an inner ring of the first shaft bearing. The first spring is preferably arranged directly on the rotor shaft.

[0019] According to a further embodiment of the electric motor, the interaction between the first support disk and the first shaft bearing or the housing can be improved by providing the first support disk with at least one projecting section extending axially along the longitudinal axis of the rotor shaft. During acceleration, this projecting section is in contact, at least partially, and in particular completely, with the first shaft bearing and / or the housing, especially with the outer ring of the first shaft bearing. Preferably, the extent of the projecting section and the outer ring are substantially identical. For example, the support disk has a greater material thickness, at least in the projecting section along the longitudinal axis of the rotor shaft, than the remaining areas of the support disk. In particular, the support disk has a first material thickness extending radially from the rotor shaft and a second, greater material thickness in the projecting section.

[0020] According to a further embodiment of the electric motor, it has proven advantageous if the second shaft bearing rests against a cover element connected to the housing, in particular by positive locking, force locking, and / or material locking. The second shaft bearing is preferably designed as an angular contact ball bearing. The cover element is, for example, pressed and / or bonded into the housing. Alternatively, the cover element is preferably welded to the housing, especially to the cylindrical section. Another alternative is that the cover element is screwed to the housing, for example, screwed into or onto the housing. The cover element is preferably arranged at the second end of the electric motor. In particular, the housing at the second end is essentially closed by the cover element, or its interior is bounded.It is particularly preferred that the second shaft bearing is at least partially arranged in the cover element. For example, the cover element has a central recess into which the second shaft bearing is at least partially, and in particular completely, inserted. Preferably, the second shaft bearing projects from the cover element at the second end face, e.g., by about 1 / 3 or 1 / 4 of its width.

[0021] Furthermore, it is preferably provided that the second shaft bearing has at least one shoulder, in particular on an outer ring, and that the shoulder of the second shaft bearing rests against the cover element. This also stabilizes the second shaft bearing in the axial direction with respect to the cover element. For example, the first shaft bearing and the second shaft bearing are identical in design.

[0022] Alternatively or additionally, the cover element is provided to have at least one recess, and the second shaft bearing rests in this recess. For example, the recess is arranged in a central recess in the cover element. The second shaft bearing preferably rests against the recess on a side facing away from the rotor, particularly with an outer ring. The inner ring of the second shaft bearing is preferably arranged directly on the rotor shaft.

[0023] Another embodiment of the electric motor provides that the rotor has at least one second support disk. For example, the second support disk is arranged at the second end of the electric motor. Preferably, the second support disk is arranged on the side of the rotor facing the second shaft bearing. The support disk is preferably arranged between the rotor and a motor circuit board. In particular, the second support disk has at least one conically tapered section. Preferably, the section tapers towards the second shaft bearing. The second support disk is arranged on the end face of the rotor, in particular directly on the rotor shaft. Preferably, the first support disk and the second support disk are made of the same material, e.g., bronze.

[0024] The presence of the second support disc further increases the resistance of the electric motor, even under strong deceleration.

[0025] Another embodiment provides that at least one bearing sleeve is arranged, particularly at the second end of the electric motor. The bearing sleeve is located on the rotor shaft, and the second shaft bearing, particularly with its inner ring, is arranged on the bearing sleeve. The bearing sleeve extends along the rotor shaft, for example, between the second shaft bearing and the rotor or the second support disk. It is also possible for the bearing sleeve to extend only in the area of ​​the second shaft bearing. The bearing sleeve is, in particular, surrounded by the cover element.

[0026] The bearing sleeve has, in particular, at least one circumferential projection. The circumferential projection is, for example, located approximately in the center of the longitudinal extent of the bearing sleeve. The radial height of the projection corresponds, in particular, to approximately the radial height of an inner ring of the second shaft bearing. In particular, the circumferential projection abuts the inner ring of the second shaft bearing.

[0027] Preferably, the bearing sleeve is designed such that the second support disc rests against the bearing sleeve when the electric motor is accelerated or decelerated in such a way that the rotor shifts in the direction of the second shaft bearing.

[0028] For example, it is provided that the bearing sleeve is supported at least indirectly by the rotor in one direction along the rotor axis. Preferably, at least one second spring is arranged between the bearing sleeve and the rotor, in particular between the bearing sleeve and the second support disk. The second spring is, for example, designed as a coil spring. In particular, the second spring is arranged in a recess in the bearing sleeve surrounding the rotor shaft and is supported longitudinally against the second support disk. The first and second springs serve to center the rotor, especially during operation.

[0029] A printed circuit board (PCB) is preferably arranged within the housing of the electric motor and positioned in the interior of the housing. The PCB comprises, for example, power electronics and / or control electronics and / or at least one sensor and / or at least one communication interface. For example, the PCB is arranged longitudinally between the first shaft bearing and the second shaft bearing. In particular, the PCB is positioned closer to the second end face than to the first end face. To advantageously prevent damage to the PCB during acceleration of the electric motor, at least one support element is provided. The PCB is positioned at least partially on a side of the support element facing the second shaft bearing and rests at least partially against the support element.The support element is designed to be so stable that it limits and / or prevents deflection of the printed circuit board. For example, the support element has multiple recesses to accommodate the coil connections for the stator. The support element is designed to be in the form of a ring.

[0030] Another embodiment of the electric motor provides that the electric motor has at least one outer casing, and that the outer casing completely surrounds the housing. The outer casing is preferably cup-shaped with a closed and an open end. It is particularly preferred that a gearbox with its gearbox housing is arranged at the second end of the motor, and that the outer casing of the electric motor is welded circumferentially to the gearbox housing. Preferably, the open end of the outer casing is oriented towards the gearbox, so that this open end is closed by the gearbox housing. The gearbox can be driven, in particular, by a pinion connected to the rotor shaft. The gearbox housing, in particular, has at least one support element. The support element is, for example, ring-shaped.In its assembled state, the support element rests against the cover element and the second shaft bearing, holding the second shaft bearing in position along its longitudinal axis. Specifically, the support element is designed to rest only against the second shaft bearing. The outer casing provides advantageous stability to the electric motor and gearbox unit.

[0031] Alternatively, the gearbox housing is welded to the electric motor housing, particularly to the cylindrical section. For example, the gearbox housing is at least partially pushed onto the motor housing.

[0032] The gearbox housing is characterized, for example, by having its largest diameter in the connection area to the electric motor. Preferably, the diameter of the gearbox housing, with the exception of the connection area, is smaller than the diameter of the electric motor housing. Starting from the diameter of the electric motor in the connection area, the diameter of the gearbox housing decreases, for example, in a transition area. This transition area extends, for example, from a side of the support element in the gearbox housing facing away from the second shaft bearing. All diameters of the gearbox following the transition area in the axial direction are, for example, smaller than or equal to the diameter following the transition area.

[0033] The outer casing and / or the gearbox housing are preferably made of stainless steel.

[0034] It is particularly preferred that the printed circuit board is at least partially, and in particular completely, embedded in a potting compound. The potting compound preferably rests against the cover element. It is particularly preferred that the support for the printed circuit board is at least partially supported by the potting compound. It is particularly preferred that the coil connections of the stator are laid loosely, and in particular in a substantially wave-like manner, relative to the printed circuit board in order to prevent damage in the event of any movement of the printed circuit board relative to the stator. Furthermore, this simplifies calibration if a digital sensor is present.

[0035] The invention can also be described based on the following aspects: Aspect 1: Electric motor comprising at least one housing, at least one rotor and at least one stator, wherein the rotor has at least one rotor shaft, wherein the rotor shaft is supported by at least one first shaft bearing and at least one second shaft bearing, wherein the first shaft bearing has an outer ring, characterized in that the rotor has at least one first support disk, and that the first support disk is designed to support the rotor against the outer ring during axial acceleration along a longitudinal axis of the rotor shaft. Aspect 2: Electric motor comprising at least one housing, at least one rotor and at least one stator, wherein the rotor has at least one rotor shaft, wherein the rotor shaft is supported by at least one first shaft bearing and at least one second shaft bearing, wherein the first shaft bearing has an outer ring, characterized in that the rotor has at least one first support disk, and that the first support disk is designed to support the rotor against the outer ring and / or against the housing during axial acceleration along a longitudinal axis of the rotor shaft.

[0036] In such an electric motor according to one of the two aspects, the support disc is arranged at an arbitrary end. It is provided that the housing is closed at the first end with a cover element and has a one-piece housing base at the second end. Alternatively, it is also provided that the housing is closed at both end with a cover element, which is, for example, each welded to a cylindrical section. Further embodiments of such electric motors result from the described exemplary embodiments and their features, to which reference is also made here for these aspects and the aforementioned electric motors. In particular, it is also within the scope of the invention to subordinate claims with the features of dependent claims 2 to 16 to each of these aspects and electric motors. Any existing definite articles would then have to be changed to indefinite articles.

[0037] Further advantageous embodiments of the invention will become apparent from the following description of the figures and the dependent subclaims.

[0038] They show: Fig. 1 an embodiment of a motor according to the invention with attached gearbox in a partially cutaway view, Fig. 2 an embodiment of an electric motor in section along the rotor axis, and Fig. 3 Another embodiment of an electric motor in section along the rotor axis.

[0039] In the various figures of the drawing, identical parts are always labelled with the same reference symbols.

[0040] The following description claims that the invention is not limited to the exemplary embodiments and not to all or several features of the described combinations of features; rather, each individual partial feature of the exemplary embodiment(s) is also significant for the subject matter of the invention, independent of all other partial features described in connection therewith, both on its own and in combination with any features of another exemplary embodiment.

[0041] Fig. Figure 1 shows an embodiment of an electric motor 1 connected to a gearbox 2, in a partially cutaway side view. The cutaway section shows the area where the electric motor 1 is attached to the gearbox 2. Fig. 2 and Fig. Figures 3 each show a different embodiment of a motor according to the invention in a sectional view along a rotor shaft 6.

[0042] According to Fig. 2 and Fig. In the electric motor 1, each housing 3 contains at least one housing 3 in which a rotor 4 and a stator 5 are arranged. The rotor shaft 6 runs centrally through the housing 3. The rotor shaft 6 is supported by a first bearing 7 and a second bearing 8. The first bearing 7 has an outer ring 7a, on which, in this embodiment, a shoulder 9 is formed. The shoulder 9 rests against the housing 3. Alternatively, no shoulder 9 is provided on the first bearing 7, and the first bearing 7 is arranged directly, at least partially, within the housing 3, e.g., like the second bearing 8 of the Fig. 3. The rotor 4 exhibits according to Fig. 2 and Fig. 3. At least one first support disk 11 is located on the first end face 10 of the rotor 4, which is also oriented towards the first end face 10. The first support disk 11 is arranged on the end face of the rotor 4 at a first end face 10 of the electric motor 1. The first support disk 11 is arranged with its inner circumference on a shoulder made of plastic on the rotor 4.

[0043] The support disc 11 is designed here to support the rotor 4 against the outer ring 7a of the first shaft bearing 7 when the electric motor 1 is axially accelerated such that the rotor 4 moves in the direction of the first shaft bearing 7, according to Fig. 2 For example, an acceleration to the left. If such an acceleration occurs, the first support disk 11, together with the rotor 11, bears against the outer ring 7a of the first shaft bearing 7 and thus transmits forces from the rotor 4 to the housing 3. Alternatively, it is provided that the electric motor 1 is designed such that the support disk 11 bears at least partially or exclusively against the housing 3.

[0044] The stepped shoulder 9 of the first shaft bearing 7 rests on an inner surface of the housing 3 facing the rotor 4, in a recess 12 within a recess 13 in the housing 3. The recess 12 is slightly deeper in the axial direction along the longitudinal axis A than the axial extent of the shoulder 9, so that the shoulder 9 and the support disk 11 are spaced apart during operation. During operation, the support disk 11 is positioned axially approximately at the level of the beginning of the recess 12, so that the support disk 11 moves into the recess 12 or the recess 13 during acceleration.

[0045] The housing 3 has a cylindrical section 3a that substantially surrounds the motor 1 along its longitudinal axis, and a housing base 3b formed integrally with the cylindrical section 3a. The first support disk 11 faces the housing base 3b. The recess 13 is arranged in the housing base 3b and extends completely through it, so that the first shaft bearing 7 also passes through the housing base 3b together with the rotor shaft 6. The first shaft bearing 7 protrudes from the housing base 3b at its first end face 10. The rotor shaft 6 is arranged substantially flush with the first shaft bearing 7.

[0046] The rotor 4 is manufactured by means of plastic injection molding, so that the at least one permanent magnet 4a is formed onto the rotor shaft 6 by means of plastic elements 4b.

[0047] The rotor 4 has at least one first spring 14, which is designed here as a disc spring, and which biases the rotor 4 towards the second shaft bearing 8 or the second end face 19. The first spring 14 is arranged directly on the rotor shaft 6 and is supported against the rotor 4 and against an inner ring 7b of the first shaft bearing 7. The first support disk 11 is designed such that it has a projecting section 11a extending axially along the rotor shaft 6, which is thicker in the axial direction than a radially inner section of the support disk 11. Only the projecting section 11a bears against the outer ring 7a during acceleration. The radial extent of the projecting section 11a corresponds approximately to the radial extent of the outer ring 7a of the first shaft bearing 7.

[0048] On the side of the housing 3 opposite the housing base 3b, namely the second end face 19, the housing 3 is closed with a cover element 15. The cover element 15 has an external shoulder 16 onto which the cylindrical section 3a of the housing 3 is slid. The cover element 15 is pressed into the housing 3 and bonded to the housing 3.

[0049] The second shaft bearing 8 rests against the cover element 15 and is at least partially arranged in the cover element 15. In the exemplary embodiment of the Fig. 2 The second shaft bearing 8 has a radially outwardly projecting, step-like shoulder 17 on an outer ring 8a, which abuts the end face of the cover element 15. Furthermore, the second shaft bearing 8 is at least partially arranged in a central recess 18 in the cover element 15. An inner ring 8b of the second shaft bearing 8 is arranged directly on the rotor shaft 6. At the second end 19 of the electric motor 1, the rotor shaft 6 protrudes from the housing 3. A pinion 20 for interaction with the [missing information] is also mounted on the rotor shaft 6. Fig. The gear 2 shown in Figure 1 is arranged in the gearbox 2. The pinion 20 is preferably welded to the rotor shaft 6, e.g. by spot welds.

[0050] In the exemplary embodiment of the Fig. 3 The cover element 15 has a recess 21 in the central recess 18, so that the second shaft bearing 8 with its outer ring 8a can bear axially against the cover element 15 on the side of the cover element 15 facing away from the rotor 4. In the exemplary embodiment of the Fig. At the second end face 19, a second support disc 22 is arranged, which rests against the rotor 4 and has a section 22a that tapers conically towards the second shaft bearing 8. A bearing sleeve 23 is also provided at the second end face 19 and is located on the rotor shaft 6. The second shaft bearing 8 is supported on the bearing sleeve 23 by an inner ring 8b. Here, the second shaft bearing 8 is designed as an angular contact bearing and is, in particular, larger than the first shaft bearing 7.

[0051] The bearing sleeve 23 has a circumferential projection 24, which is at least partially located on a potting compound 25 of the electric motor 1. Furthermore, the inner ring 8b of the second shaft bearing 8 bears against the circumferential projection 24 on the side facing away from the rotor 4. The bearing sleeve 23 is supported at least indirectly by the rotor 4, in this case via the second support disk 22. For this indirect support, the bearing sleeve 23 has a recess 26 radially surrounding the rotor shaft 6, in which a second spring 27 in the form of a coil spring is arranged. The second spring 27 bears axially against the bearing sleeve 23 and against the second support disk 22, so that the rotor 4 is resiliently centered between the first spring 14 and the second spring 27. The second spring 27 pushes the rotor 4 towards the first shaft bearing 7 or the first end face 10.

[0052] At least one printed circuit board 28 is arranged in an interior space enclosed by the housing 3, in particular by the housing 3 and the cover element 15. The printed circuit board 28 rests against the support element 29 on the side of a support element 29 facing the second shaft bearing 8. The printed circuit board 28 is arranged in the housing 3 between the first shaft bearing 7 and the second shaft bearing 8.

[0053] The support 29 according to Fig. In addition to an outer ring 29a, component 2 also has an inner element 29b. The circuit board 28 is at least partially enclosed by the potting compound 25. The coil connections 30, which are arranged between stator 5 and circuit board 28, are loosely or corrugated to allow for the calibration of a digital sensor – if present – ​​and / or to ensure that the coil connections 30 are de-energized if there is relative movement between circuit board 28 and stator 5.

[0054] According to Fig. In this case, the motor 1 is preferably enclosed, in addition to the housing 3, by a cup-shaped outer shell 31, which completely surrounds the housing 3 of the electric motor 1, particularly also in the area of ​​the housing base 3b. The outer shell 31 is welded to a gearbox housing 32 of the gearbox 2 by a circumferential weld seam 33, particularly by laser welding. By welding the outer shell 31 to the gearbox housing 32, a support element 35 is also fixed in the axial direction, which also fixes the second shaft bearing 8 to the cover element 15. The gearbox 2 can be driven by the pinion 20 arranged on the rotor shaft 6. The connections 34 of the motor 1 are led to the outside through the housing 3 and the outer shell 31 and sealed at the housing 3 and the outer shell 31, respectively, e.g., by potting.

[0055] The invention is not limited to the embodiments illustrated and described, but also encompasses all embodiments that have the same effect within the meaning of the invention. It is expressly emphasized that the embodiments are not limited to all features in combination; rather, each individual feature can also have inventive significance independently of all other features. Furthermore, the invention is not yet limited to the combination of features defined in claim 1, but can also be defined by any other combination of specific features from all disclosed individual features. This means that, in principle, virtually any individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application. Reference symbol list 1 electric motor 2 gearboxes 3 cases 3a Cylindrical section 3b Case bottom 4 Rotor 4a Permanent magnet 4b Plastic element 5 Stator 6 Rotor shaft 7 First shaft bearing 7a Outer ring 7b Inner ring 8 Second shaft bearing 8a Outer ring 8b inner ring Paragraph 9 10 First end page 11 First support disc 11a Advantage area 12 Return 13 Exclusion 14 First spring 15 lid element 16th paragraph of the lid element 17th paragraph of the second shaft bearing 18 Central recess 19 Second end page 20 sprockets 21 Recess of the lid element 22 Second support disc Section 22a 23 Bearing sleeve 24 lead 25 potting compound 26 Exclusion 27 spring 28 circuit boards 29 Support materials 29a Outer ring 29b Inner element 30 coil connection 31 Outer shell 32 Gearbox housings 33 weld seam 34 connections 35 Support element

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