Electric machine

Abstract

An electric machine (8), in particular an electric motor, with a rotor (7) and a shaft (10), wherein the rotor (7) has several laminations (5), wherein the laminations (5) are pre-assembled onto the shaft individually or as a lamination pack (6) or by means of several lamination packs (6), and wherein the laminations (5) and / or the lamination packs (6) are at least indirectly connected to the shaft (10), characterized in that a resilient projection (3) is formed on at least one lamination (5) of each lamination pack (6), which serves to at least indirectly fasten the lamination pack (6) to the shaft (10), and that a centering shoulder (1) is formed on the lamination (5) and / or on at least one further lamination (5), which serves to center the lamination pack (6) at least substantially radially relative to the shaft (10), or, if the rotor is constructed from several individual laminations (5) is,Each individual lamella (5) has at least one resilient projection (3) and at least two radially opposing centering shoulders (1), wherein the centering shoulder (1) is designed with a clearance or transition fit towards the shaft (10).

Description

Prior ArtThe invention relates to an electric machine, in particular an electric motor having a rotor and a shaft. The invention relates in particular to the field of electric motors for motor vehicles, in particular of electric motors serving as electric auxiliary drives for power-operated adjustment or for supporting adjustment of elements of a motor vehicle.DE 195 23 789 A1 discloses an electric motor having a rotor, a stator and further components which are accommodated in a housing of the electric motor. A plurality of stator windings are located on a stator core on the stator. Such a stator core is fixedly attached to the outer periphery of a supporting sleeve and is made of magnetic or magnetizable material. Furthermore, the rotor is fixedly mounted on a shaft of the electric motor. In operation, the control current to the various stator windings on the armature of the stator is controlled by a control circuit so as to produce a rotating magnetic field inside the motor. This then drives the rotor.The electric motor known from DE 195 23 789 A1 has the disadvantage that the fastening of the plates and / or the plate assemblies to the shaft is complicated and requires, in particular, a few working steps.The preamble of claim 1 is known from JP 2000-232 744 A. Further prior art is known from DE 202 02 161 U1, DE 695 07 996 T2, JP 2006-217 770 A and JP 2000-295 824 A.Rotors can be constructed from one or more disk packs or from individual disks and further components. The plates or plate assemblies are pushed axially onto the shaft so that they are directly adjacent to one another.It is conceivable that the attachment of the plates and / or the plate packs to the shaft is carried out by a cylindrical press fit. So that the forces do not increase too much when the plate assemblies are pressed onto the shaft, the joining partners can be closely tolerated. However, this means high production costs, which are too expensive for many applications. In connections in which the fastening is produced exclusively by an interference fit, grooves are formed on the shaft and the packets as a result of the high overlap during the joining. The shape and depth of the grooves have a high scatter, whereby errors in coaxiality and an insufficiently large holding force occur in the assembled state. In addition, these values can scatter very strongly.Furthermore, a solution is conceivable in which notches and / or elevations are provided on the shaft at the joint or the shaft is knurled at the joint. In this solution, additional working steps are necessary for applying the notches or knurling, wherein these methods are limited to a certain overall length. In the knurl solution, the coaxiality after assembly is not sufficient for all applications. Furthermore, by making the notches or knurling, especially for a long length of the packages, there is a risk that the shaft will become uneven.In addition, solutions are conceivable in which the lamellae have notches and / or elevations. When the plate assemblies are pressed on from notched plates, a firm connection is formed at the joint. In these embodiments, a large error arises in the coaxiality of a disk pack, from which the rotor can be constructed, with respect to the shaft, since the notches deform in an undefined manner and there is generally no additional region at the joint, which generates the coaxiality of the disk pack with respect to the shaft.Disclosure of the InventionThe electric machine according to the invention having the features of claim 1 and the electric machine according to the invention having the features of claim 14 have the advantage over the related art that an improved mounting of the rotor on the shaft or the stator in the housing part is made possible. In particular, a relatively cost-effective production can be made possible, in which the desired radial centering of the lamination stack of the rotor or of the lamination stack of the stator with respect to the shaft of the electric machine is ensured.The measures listed in the dependent claims allow advantageous refinements of the electric machine specified in claim 1 or of the electric machine specified in claim 14.It is advantageous that the resilient shoulder is of nose-shaped design. The nose-shaped shoulder can be bent somewhat during assembly, so that a reliable radial centering results and, in addition, a certain prestress in a radial direction is made possible.It is furthermore advantageous that a form-fitting connection is formed between the shaft and the resilient shoulder. In particular, a nose-shaped shoulder can be designed such that a very high surface pressure locally occurs when the plate pack is joined onto the shaft or the plate pack into the housing part, as a result of which a notch is formed on the shaft and as a result, in addition to the force-fit connection, a form-fit connection also occurs locally. This allows reliable fastening with a correspondingly high connecting force. The connection can then serve for positioning and fixing.One or more resilient attachments are advantageously formed on a plurality of lamellae of the lamella package, wherein a free space is provided behind a resilient attachment in an axial direction, whereby a certain bending of the resilient attachment is made possible during the assembly.The spring force applied by the resilient shoulder preferably acts in such a way that the centering shoulder is acted upon in the direction of the shaft or towards the housing part in order to ensure reliable radial centering of the disk pack relative to the shaft.It is furthermore advantageous that the centering shoulder is designed with a clearance or transition fit towards the shaft or the housing part. As a result, the disk pack can be easily applied to the shaft or introduced into the housing part. In the case of a certain, slight positive overlap with respect to the shaft or the housing part, an elastic configuration of the centering shoulder can also be effected in order to facilitate assembly.It is furthermore advantageous that the shaft is continuously designed at least in a region of the disk pack or that an inner surface of the housing part is continuously designed at least in a region of the disk pack. The resilient shoulder or the resilient shoulders enable a force-fit connection, optionally also a force-fit connection, in which a shoulder on the shaft or the housing part is not required for fastening in the axial direction, so that a simplified and thus cost-effective configuration of the shaft or the housing part is made possible.When assembling lamellae and / or lamellae packages into a housing, it may be expedient, depending on the material and stress of the connection, if the housing has groove-shaped depressions into which the clamping nails enter. This is advantageous in the event of extreme loading of the connection.Advantageously, the resilient shoulder is configured to have a width decreasing in a radial direction. In this case, the rigidity decreases inwardly when it is fastened to the shaft and thus toward the shaft, while the rigidity decreases outwardly when it is fastened to the housing and thus toward the housing. In particular, the decreasing stiffness in the radial direction can be achieved by a configuration of the resilient shoulder in which a decreasing material thickness is provided in the radial direction. In particular, it is advantageous that a tangential width of the resilient shoulder decreases in the radial direction. These measures have the advantage that the resilient shoulder is subjected to as uniform a stress as possible, in particular expansion and stress, during the joining to the shaft or into the housing and, in the assembled state, in the radial direction over the expansion of the resilient shoulder. As a result, the stress on the resilient shoulder viewed at points is reduced, in particular a narrow radius of curvature occurring at points is avoided, and thus the safety against damage to the resilient shoulder is increased. In an advantageous manner, an at least substantially uniform curvature of the resilient shoulder can be achieved in the joining process, so that the resilient shoulder is bent over in a substantially uniformly curved manner.Advantageously, a tangential position of a plurality of resilient shoulders of a plurality of slats arranged at least substantially one behind the other varies. As a result, the resilient shoulders load two or more tracks during the joining to the shaft or into the housing, so that the risk of chip formation during the joining is reduced. In particular, the tangential position of the resilient shoulders of the plurality of plates can be designed to be variable such that (almost) each of the resilient shoulders arranged substantially one behind the other has its own track during the joining to the shaft or into the housing.Advantageously, a form fit is formed between the disk pack and the shaft in a circumferential direction. This prevents rotation in the circumferential direction, that is to say about an axis of the shaft, between the disk pack and the shaft, with the result that a reliable connection is formed between the disk pack and the shaft in the load direction which is mainly relevant during operation. Accordingly, it is advantageous that a form fit is formed between the lamination stack of the stator and the housing part in a circumferential direction.It is advantageous that the form-fit formed in the circumferential direction is formed between a plate of the plate pack and the shaft. It is advantageous here that the shaft has a recess into which the resilient shoulder of the plate of the plate pack partially engages, so that the positive fit is formed in the circumferential direction. This enables a cost-effective configuration of the form fit. In this case, a plurality of resilient attachments can be provided in particular, wherein one or more resilient attachments engage in at least one recess of the shaft. The recess in the shaft can be formed in particular by a groove in the shaft running in an axial direction. Corresponding advantages also result in a corresponding configuration of the form fit between the lamination stack of the stator and the housing part.Brief Description of the DrawingsPreferred exemplary embodiments of the invention are explained in more detail in the following description with reference to the attached drawings, in which corresponding elements are provided with corresponding reference numerals. It shows: FIG. 1 shows a lamination of a lamination stack of a rotor of an electric machine according to a first exemplary embodiment of the invention; FIG. 2 shows a lamination of a lamination packet of a stator together with a housing part of an electric machine according to a second exemplary embodiment of the invention; FIG. 3 shows a simplified, partial illustration of a section through a stack of lamellae according to a third exemplary embodiment for further explanation of the invention; FIG. 4 shows a lamination of a lamination stack of a rotor of an electric machine according to a fourth exemplary embodiment of the invention; FIG. 5 shows the detail, denoted by V in FIG. 4, of a lamination of a lamination stack of a rotor of an electric machine according to the fourth exemplary embodiment of the invention; FIG. 6 shows a schematic, partial illustration of a section through a lamination stack joined to a shaft, according to the fourth exemplary embodiment of the invention; FIG. 7 shows a lamination of a lamination stack of a stator of an electric machine according to a fifth exemplary embodiment of the invention, and FIG. 8 shows a stator with a housing part of an electric machine according to a sixth exemplary embodiment of the invention.DESCRIPTION OF THE EMBODIMENTSFIG. 1 shows a lamination 5 of a lamination stack 6 of a rotor 7 of an electric machine 8 (FIG. 2 ). The electric machine 8 can be designed in particular as an electric motor for a motor vehicle. The electric machine 8 is particularly suitable for power-operated adjustment of elements of a motor vehicle, for example a sliding roof, a window or a seat element. Furthermore, the electric machine 8 can serve as an electric motor for steering power assistance. However, the electric machine 8 according to the invention is also suitable for other applications.The disk 5 of the disk pack 6 of the rotor 7 has a centering shoulder 1, which enables a concentric receptacle of a shaft, which can be introduced into a central recess 9 of the disk 5. Furthermore, the lamella 5 has a resilient shoulder 3 which is designed in the form of a nose. The resilient shoulder 3 enables fastening of individual plates 5 or plate packs 6 by means of the plate 5 on a shaft 10 (FIG. 2 ). The slat 5 has further centering shoulders which are not separately marked for the sake of simplifying the illustration. Furthermore, the lamella 5 has further resilient extensions, which are likewise not marked. In the embodiment shown in FIG. 1, the slat 5 has both centering shoulders 1 and resilient shoulders 3. A stack of lamellae 6 comprises a plurality of lamellae 5, as is illustrated in FIG. 3. It is also possible for one of the plates 5 to have at least one centering shoulder, while another of the plates 5 has at least one resilient shoulder 3. The lamella 5 has recesses 2, 4 in the region of the central recess 9. The recesses 2, 4 serve on the one hand to create a nose-shaped configuration of the resilient extension 3. On the other hand, the recesses 2, 4 are arranged such that, when the laminated core 6 is laminated with a plurality of laminations 5, a void is created behind a resilient shoulder 3 and / or a centring shoulder 1, in that successive laminations 5 are each layered one on the other in a twisted manner. As a result, when the shaft 10 is inserted into the central recess 9, a compression of the resilient shoulder 3 and / or of the centering shoulder 1 is made possible. The depth of the recesses 2, 4, which are configured in the form of grooves, can be used to preset the rigidity of the resilient shoulders 3 and / or the rigidity of the centering shoulders 1. The centering shoulders 1 can be designed such that a clearance, transition or press fit results with respect to the shaft 10. In this case, a certain positive overlap toward the shaft 10 can be provided, wherein an at least partially elastic configuration of the centering shoulder 1 is advantageous. Usually, the centering shoulders 1 are designed as a clearance fit towards the shaft 10.The resilient attachments 3 can be designed such that, when the plates 5 and / or the plate assemblies 6 are joined to the shaft 10, a high surface pressure locally occurs and, in addition to the force-fit connection, a form-fit connection also occurs locally. As a result, the shaft 10 can be configured continuously at least in the region of the disk pack 6.The centering shoulders 1 result in the advantage that coaxiality of the plates 5 and / or of the plate assemblies 6 with respect to the shaft 10 can be achieved with close tolerances. In this case, cost-effective production of the electric machine is possible, since the lamination stack 6 does not have to be remachined. Furthermore, a tolerance for the diameter of the shaft 10 can be widened, since a compensation is provided by the resilient shoulders 3 and, if appropriate, by resilient centering shoulders 1. Furthermore, relatively long plate assemblies 6 can also be mounted on the shaft 10 by a larger number of the plates 5 of a plate assembly 6 being configured with resilient extensions 3 and / or centering shoulders 1.The lamella 5 also has recesses 11, of which only the recess 11 is marked in FIG. 1. The recesses 11 serve to reduce the mass of the rotor 7 and to mount it. The lamella 5 also has slot-shaped recesses 12, of which the recess 12 is marked in FIG. 1. The slot-shaped recesses 12 of the laminated lamellae 5 are arranged one behind the other in such a way that they allow permanent magnets to be accommodated.FIG. 2 shows a lamination 5 of a lamination stack 6 of a stator 15 together with a housing part 16 of an electric machine 8 according to a second exemplary embodiment of the invention. The embodiment shown in FIG. 2 can be combined with a rotor 7 which is configured in accordance with the exemplary embodiment shown with reference to FIG. 1.The slat 5 has centering shoulders 1, 1' between which one, two or more resilient attachments 3, 3' are arranged. Recesses 2, 4 are provided in this case in order to form the resilient shoulders 3, 3' and the centering shoulders 1, 1'. The centering shoulders 1, 1' allow the stator 15 to be centered with respect to the shaft 10 in order to fix the position of the stator 15 with respect to the rotor 7.The stator 15 has a lamination stack 6 formed from a plurality of laminations 5, windings and optionally further components. To simplify the illustration, the lamella 5 is illustrated in FIG. 2 without these further components. The connection of the laminated core 6 to the housing part 16 is effected via the resilient projections 3, 3', the centring shoulders 1, 1' ensuring the positioning and centring. The centering shoulders 1, 1' in this case balance in particular different deformations of the resilient attachments 3, 3' over the circumference of the slat 5, which could otherwise occur on the basis of manufacturing tolerances and the like. As a result of the centering shoulders 1, 1', a substantially uniform deformation of the resilient attachments 3, 3' therefore also occurs, whereby the clamping force of the stator 15 in the housing part 16 is improved.This embodiment has the advantage that the coaxiality of the disk pack 6 with respect to the shaft 10 and with respect to the housing part 16 can be maintained with high accuracy and / or relatively low costs. Furthermore, due to the uniform deformation of the resilient shoulders 3, 3', which is ensured by the centering shoulders 1, 1', it is ensured that all the resilient shoulders 3, 3' deform and contribute to the clamping, so that a large clamping force is achieved. Furthermore, the assembly is facilitated, in particular since further fastening means for fastening or positioning can be omitted.The housing part 16 can at least substantially form the housing of the electric machine 8 or can constitute a part of the housing of the electric machine 8. It is also possible here for the housing part 16 itself to be assembled from a plurality of parts.FIG. 3 shows the section, denoted by I in FIG. 2, of a section along the section line denoted by II through the laminated core 6 from the viewing direction denoted by III, in accordance with a third exemplary embodiment of the invention. The lamination pack 6 of this embodiment has a central part 17 formed of a plurality of laminations 5. Here, two kinds of blades 5 are provided, namely, blades 5A and blades 5B alternately stacked in succession. Furthermore, end disks 5C and 5D joined to the middle part 17 are provided, wherein no or more end disks 5C and 5D can also be provided at each end of the disk stack 6. The plate 5A is designed such that a free space 19 is provided in an axial direction 18 both behind the centering section 1 of the plate 5B and behind the resilient shoulder 3, which free space permits a compression of the resilient shoulder 3 and, if appropriate, of the centering shoulder 1 when the plate pack 6 is mounted on the shaft 10. Accordingly, one of the plates 5B is designed such that a free space 20 is provided behind the resilient shoulder 3' in the axial direction 18.When the laminated core 6 is joined to the shaft 10 or into the housing part 16, the resilient attachments 3, 3' are deformed, in particular bent in the axial direction 18. After the bending, the resilient projections 3 and the resilient projections 3' therefore project beyond the lamellae 5B and 5A, respectively. In order that an end face 21 of the plate pack 6 can serve as a stop for another component, for example a spring or a further plate pack, which can be designed in accordance with the plate pack 6, the end face 21 is formed by the end plate 5D, which has no resilient projections 3, 3' and no centring shoulders 1, 1'. In a corresponding manner, an end face 22 is formed by an end plate 5C. At the respective end of the disk pack 6, no or two or more end disks 5C, 5D can also be provided. It is also possible, furthermore, for lamellae corresponding to the end lamellae 5C, 5D to be provided within the lamella stack 6, in order to create the free space 2 and / or the free space 4 and / or the free space 19 and / or the free space 20. In the exemplary embodiment shown, a free space 19, 20 is provided behind a resilient shoulder 3, 3'. Especially in the case of thin plates 5A, 5B, which can be produced from thin metal sheets, or if a rather stiff, in particular very stiff, connection is required, two or more resilient attachments 3, 3' can also lie one behind the other in the axial direction 18, so that a free space 19, 20 follows in each case two or more resilient attachments 3, 3' lying one behind the other.When producing the lamellae 5, slides or individual punches can be provided for producing the resilient attachments 3, 3' in the punching tool, which slides or individual punches are automatically adjusted, namely such that lamellae 5 can be produced with and without resilient attachments 3, 3' in the required sequence as is required when packaging the lamella packet 6.The structure of the disk pack 6 illustrated in FIG. 3 is also possible in a corresponding manner in the disk pack 6 of the rotor 7 illustrated in FIG. 1.In the first exemplary embodiment described with reference to FIG. 1, there is the advantage that the shaft 10 can have no steps or a reduced number of steps. In the second exemplary embodiment described with reference to FIG. 2, there is the advantage that an inner surface 25 of the housing part 16 can be configured continuously at least in a region of the disk pack 6. The resilient projections 3 can also form a positive connection in the region of the inner surface 25 of the housing part 16 in addition to a force-fit connection.FIG. 4 shows a lamination 5 of a lamination stack 6 of an electric machine 8 according to a fourth exemplary embodiment of the invention. In this case, a plurality of resilient projections 3, 3' are shown, of which only the resilient projections 3, 3' are identified in FIG. 4 for the sake of simplifying the illustration. The embodiment of the resilient projections 3, 3' is described further in detail with reference to FIGS. 5 and 6. Furthermore, for the resilient projections 3, 3', an advantageous arrangement with respect to a shaft 10 is provided. This arrangement is explained in more detail for the resilient shoulder 3'. A reference direction 30 is given for the lamella 5. The reference direction 30 is defined in this case by a center point 31 of the lamella 5 and a recess 11 of the lamella 5. However, the reference direction 30 can also be defined in another manner. The reference direction 30 is also defined here for other plates. With respect to the reference direction 30, an angular position 32 of the resilient extension 3' is given. By a certain variation of the angular position 32 of the resilient extension 3' of several lamellae 5 of a lamella packet 6, the tangential position of resilient extensions 3' arranged at least substantially one behind the other can be varied. For example, the angular position 32 of resilient shoulders of a plurality of plates arranged substantially one behind the other can vary by a few angular degrees. This has the advantage that, when joining to the shaft 10, different tracks are produced on a surface 33 (FIG. 6 ) of the shaft 10. This reduces the risk of chip formation during the joining of the lamination 5 or of the lamination stack 6 to the shaft 10.FIG. 5 shows the detail, denoted by V in FIG. 4, of a plate 5 of a plate pack 6 of a rotor 7 of the fourth exemplary embodiment of the invention, the configuration of the resilient shoulder 3 being shown in further detail. The further resilient projections of the lamella 5 and of the other lamellae of the lamella packet 6 can be designed in a corresponding manner. With respect to the resilient shoulder 3, a radial direction 34 is given, which points to the center point 31 of the lamella 5. The radial direction 34 lies at least substantially on an axis of symmetry 35 of the resilient attachment 3 that is locally given for the resilient attachment 3. In FIG. 5, points 37, 38 are selected as examples on a flank 36 of the resilient shoulder 3, wherein point 38 follows point 37 on flank 36 in the inward radial direction 34. Cross sections 39, 40 are defined by the resilient shoulder 3 by the points 37, 38, wherein the cross-sectional areas 39, 40 are each oriented perpendicular to the axis of symmetry 35. With respect to the cross section 40, the resilient shoulder 3 has a certain tangential width 41. The resilient shoulder 3 of the lamella 5 of the fourth exemplary embodiment tapers inwardly in the radial direction 34. The tangential width 41 decreases from the cross section 39 defined by the point 37 to the cross section 40 defined by the point 38. The decrease in this cross-sectional area is achieved in this exemplary embodiment by the reduction in the tangential width 41, although a thickness of the resilient shoulder 3 can also decrease. As a result, the material thickness of the resilient shoulder 3 decreases continuously in the radial direction 34. Thus, in the inward radial direction 34, a decreasing stiffness of the resilient shoulder 3 is achieved.Furthermore, the resilient extension 3 has only one head point 45. The head point 45 is the point of the resilient shoulder 3 which slides along the surface 33 during the joining to the shaft 10. It is also possible here for the resilient shoulder 3 to be somewhat flattened in the region of the head point 45.FIG. 6 shows a schematic, pull-out section through a lamination stack 6 of the fourth exemplary embodiment of the invention joined onto a shaft 10. In addition to the lamella 5, the lamellae 5E, 5F, 5G, 5H, 51, 5J are also shown. However, the plate pack 6 can also have a different number of plates 5, 5E to 5J, in particular a significantly larger number of plates. The lamella 5 has the resilient shoulder 3, which is bent over substantially uniformly curved toward the shaft 10, wherein the resilient shoulder 3 has a concavely curved end face 46 which is oriented counter to a joining direction 47. A head point 45 of the resilient extension 3 is in contact with the surface 33 of the shaft 10.However, the tangential position of the resilient projections 3, 3E, 3F, which are arranged substantially one behind the other, varies, which is achieved by a variation of the respective angular position 32 of the resilient projection 5, 5E, 5F, as is described in detail with reference to FIG. 4. Thereby, a head point 45F of the resilient projection 3F of the blade 5F is guided over the surface 33 of the shaft 10 at another circumferential position. Specifically, when the lamination stack 6 is joined to the shaft 10, a track 48F of the resilient extension 3F is formed, which is different from a track 48 of the resilient extension 5. Thus, the resilient projections 3, 3E, 3F each have their own track during the joining to the shaft 10, so that the risk of chip formation is minimized.The configuration of the plate 5, in particular of the resilient shoulder 3, and of further plates 5E, 5F described with reference to FIGS. 4 to 6, can be applied in a corresponding manner to the joint between the plate pack 6 and the housing part 16 of the electric machine 1. For example, with respect to the resilient shoulder 3 shown in FIG. 2, an outwardly directed radial direction 34' can be predetermined. The resilient shoulder 3 shown in FIG. 2 can then be designed in accordance with the fourth exemplary embodiment. In this case, the resilient shoulder 3 has a decreasing stiffness in the outward radial direction 34'. This can be achieved by the resilient shoulder 3 having a material thickness which decreases at least in sections in the outward-directed, radial direction 34', in particular by the resilient shoulder 3 having a decreasing tangential width 41 in the outward-directed, radial direction 34'. This has the advantage that the resilient shoulder 3 is bent over in an at least substantially uniformly curved manner towards the housing part 16. It is also advantageous here that a tangential position of resilient shoulders of a plurality of blades arranged substantially one behind the other varies, so that different tracks of the resilient shoulders of a plurality of blades vary, so that different tracks of the resilient shoulders are produced on the inner surface 25 of the housing part 16 during joining, so that the risk of chip formation is minimized.FIG. 7 shows a lamination 5 of a lamination stack 6 of a stator 15 of an electric machine 8 according to a fifth exemplary embodiment of the invention.Stators, in particular of EC internal rotor motors, can be fixed radially rotationally and axially non-displaceably on a surrounding housing part 16 by various methods. Bonding, mechanical pressing in with excess, tightening by means of tension anchor screws, mounting by means of pressed-in, resilient clamping pins in the gap between stator 15 and housing part 16, and thermal shrinkage are possible. These connecting methods for axially and radially fixing the stator 15 in the housing part 16, which can be formed by an aluminum profile or an aluminum die cast housing, can be replaced by the connection according to the invention. Aluminum is a possible material. Other possible materials are steels and plastics. This has the advantage that no additional parts are required and that a process-safe dimensional accuracy of the end assembly can be provided. In addition, scrapings, in particular chips which are produced with excessive dimensions during mechanical pressing-in, are reduced or prevented. Add-on parts such as adhesives, screws, clamping pins are likewise not required. Thus, the robustness of the manufacturing process of connecting the stator 15 to the case 16 can be increased. In addition, cost savings in the manufacturing process can be achieved without quality risks.The method of fastening the stator 15 of the electric machine 8 in the housing part 16 can be achieved by means of geometries which are integrally formed on the stator circumference and become barbs by mounting on the end product. The solution described below for the fastening of the stator 15 in the housing part 16 can be transferred in a corresponding manner to the fastening of the rotor 7 to the shaft 10.Especially in the invention according to the fifth embodiment, there is an advantage that the robustness of the manufacturing process of the connection between the stator 15 and the housing part 16 is increased. This increase results from the lack of add-on parts and manufacturing steps, a slight decrease in sensitivity to part dimensional tolerances between the stator 15 and the housing part 16, and the ability to reduce the quality of the housing surfaces because of the ability to permanently compensate for tolerances to some extent, with rougher surfaces promoting the holding forces of the joint. There is also the advantage that costs can be saved in the production process. Such cost savings are achieved by relatively simple installations, since only one press with force-travel monitoring is required, and by avoiding the handling of additional parts with all corresponding consequences, such as parts management, storage, interrogation for existing parts. There is also the advantage of being simple to produce, of being simple to process, of a non-detachable connection which compensates for tolerances and is optionally subject to rotation-proof, and of being able to be used on both sides, that is to say independently of the axial direction. These advantages also result in particular in the sixth exemplary embodiment described with reference to FIG. 8.In the sipe 5 of the fifth embodiment of the invention illustrated in FIG. 7, a circumferential contour 50 of the sipe 5 is formed by punching or the like deviating from a circular shape. Resilient projections 3, 3', 3'' are provided between which there is an angular spacing of 120°. Furthermore, recesses 51 are provided, of which the recess 51 is marked in FIG. 7. The recesses 51 are recessed with respect to a radius 52 of the lamella 5. Furthermore, the resilient attachments 3, 3', 3'' extend at least approximately as far as the radius 52. It is advantageous that the resilient attachments 3, 3', 3'' project somewhat beyond the radius 52 of the lamella 5, so that in the case of a housing part 16 with a fully cylindrical contour of the inner surface 25 (FIG. 2 ), a bending of the resilient attachments 3, 3', 3'' is achieved during the joining. This facilitates the production of the housing part 16. The resilient projections 3, 3', 3'' can, however, also be guided up to the radius 52 or even fall below the latter. However, this requires a counterpart, i.e. here an inner surface 25 of the housing part 16, having a not fully cylindrical contour. This not fully cylindrical contour can be designed in such a way that it is guided at least in the region of the resilient shoulders 3, 3', 3'' as far as the radius 52 or into the latter. This also makes it possible to achieve reliable fastening by springing in the resilient attachments 3, 3', 3'' during joining.The circumferential contour 50 does not necessarily have to be formed from a circular shape. In particular, the peripheral contour 50 can start from a polygonally shaped contour which can be modified according to the configuration shown in FIG. 7 by providing recesses 51 and resilient shoulders 3, 3', 3''. In this case, it is decisive that the circumferential contour 50 in the region of the resilient attachments 3, 3', 3'', that is to say in the region of contact with the inner surface 25 of the housing part 16, is designed such that, in combination with this inner surface 25, there is an oversize in order to enable the function of the resilient attachments 3, 3', 3''. Furthermore, a slight air gap can be located between the lamination stack 6 of the stator 15 and the inner surface 25 of the housing part 16 within the regions in which no contact between a lamination and the housing part 16 is desired.In addition, the lamella 5 of the fifth exemplary embodiment of the invention shown in FIG. 7 has at least one projection 53 with a semicircular contour. The projection 53 protrudes significantly beyond the radius 52. In particular, the projection 53 protrudes significantly further beyond the radius 52 than the resilient shoulders 3, 3', 3''. By means of the projection 53 of the slat 5, a form fit in a circumferential direction 55 with the housing part 16 can be formed. The projection 53 engages in a recess 54 in the inner surface 25 of the housing part 16, which recess is formed by a groove running in an axial direction. When the stator 15 is joined into the housing part 16, the protrusion 53 is positioned with respect to the recess 54.In FIG. 7, a projection 53 is shown. However, a plurality of projections configured in accordance with the projection 53 can often be provided on the circumferential contour 50. The angular spacing between such projections can be selected with respect to the respective application. The projection 53 can completely prevent a rotation of the stator 15 relative to the housing part 16 in the circumferential direction 55.FIG. 8 shows a lamination 5 of a lamination stack 6 of a stator 15 with a housing part 16 of an electric machine 8 according to a sixth exemplary embodiment of the invention. In this exemplary embodiment, the lamella 5 has a plurality of resilient extensions 3, 3', 3'', of which only the resilient extensions 3, 3', 3'' are marked in FIG. 8 for the sake of simplifying the illustration. Furthermore, the housing part 16 has a plurality of recesses 54, 54', 54" on the inner surface 25, of which recesses 54, 54', 54" are only marked in FIG. 8. In this exemplary embodiment, both the resilient attachments 3, 3', 3'' and the recesses 54, 54', 54'' are arranged on the lamella 5 or the housing part 16 in the circumferential direction 55 in a regular repeating manner, so that positioning during the joining of the stator 15 into the housing part 16 is simplified. By means of an asymmetrical arrangement, a certain position of the stator 15 with respect to the housing part 16 can conversely also be predefined in the circumferential direction 55.The resilient shoulder 3 engages in the recess 54 during the joining, wherein the resilient shoulder 3 protrudes clearly beyond the radius 52 and is bent over within the recess 54 during the joining. The same applies to the resilient shoulder 3' and the recess 54' as well as the resilient shoulder 3" and the recess 54". The recesses 54, 54', 54" can be configured groove-shaped, wherein the respective groove extends in an axial direction.It should be noted that after joining, a force acting in the axial direction counter to the pressing-in direction causes the resilient attachments 3, 3', 3'' to be clawed in the respective recess 54, 54', 54'', wherein a local micro-form closure is formed. Thus, burying of the resilient projections 3, 3', 3'' in the inner surface 25 in the region of the recesses 54, 54', 54'' can be achieved.By engaging the resilient projections 3, 3', 3'' in the recesses 54, 54', 54'', a positive fit is thus ensured also in the circumferential direction 55, which permits a complete anti-rotation means. Thus, a reliable fastening of the stator 15 in the housing part 16 is achieved precisely in the main load direction, i.e. in the circumferential direction 55.During assembly, the stator 15 can be inserted into the housing part 16 by means of a press. The described respective interference between the resilient extension 3, 3', 3'' and the associated recess 54, 54', 54'' in the inner surface 25 of the housing part 16 forces the resilient extensions 3, 3', 3'' to deform in a defined manner in the contact region. In this case, there may be a plastic portion and a permanently residual elastic residual amount. The bending can be facilitated by a chamfer in the insertion region. By suitably designing the resulting installation angle of the resilient projections 3, 3', 3'', the stator 15 is permanently secured in the housing part 16. In order to promote a defined deformation of the resilient attachments 3, 3', 3'', they are provided at only certain distances on lamellae of the lamella packet 6, as viewed axially, in order to avoid the resilient attachments resting against one another, as is also described in detail with reference to FIGS. 3 and 6. Otherwise, there would be the risk that the press-in forces increase disadvantageously strongly and the individual laminations of a lamination stack 6 separate from one another and the stator 15 breaks down into its individual parts.It should be noted that the configuration of the connection between the stator 15 and the housing part 16 described with reference to FIGS. 7 and 8 is correspondingly applicable to the connection between a rotor 7 and a shaft 10 of the electric machine 8.The invention is not limited to the described exemplary embodiments.

Claims

Electric machine (8), in particular an electric motor, having a rotor (7) and a shaft (10), wherein the rotor (7) has a plurality of plates (5), wherein the plates (5) are joined onto the shaft in a pre-assembled manner individually or as a plate pack (6) or by means of a plurality of plate packs (6), and wherein the plates (5) and / or the plate packs (6) are connected at least indirectly to the shaft (10), characterized in that a resilient shoulder (3) is formed for each plate pack (6) on at least one plate (5), said resilient shoulder serving for at least indirectly fastening the plate pack (6) to the shaft (10), and in that a centring shoulder (1) is formed on the plate (5) and / or on at least one further plate (5), said centring shoulder serving for at least substantially radially centring the plate pack (6) relative to the shaft (10) or, If the rotor is constructed from a plurality of individual laminations (5), each individual lamination (5) has at least one resilient shoulder (3) and at least two radially opposite centring shoulders (1), the centring shoulder (1) being designed with a clearance or transition fit towards the shaft (10).Electric machine according to Claim 1, characterized in that the resilient shoulder (3) is of nose-shaped design.Electric machine according to Claim 1 or 2, characterized in that the resilient shoulder (3) is prestressed at least in a radial direction and the plates and / or the plate assemblies are thereby fixed in a force-fitting manner on the shaft.Electric machine according to Claim 3, characterized in that a form-fitting connection is formed between the shaft (10) and the resilient shoulder (3).Electric machine according to one of Claims 1 to 4, characterized in that resilient attachments (3) are formed on a plurality of laminations (5) of the lamination stack (6), and in that a free space (19) is provided behind a resilient attachment (3) at least in an axial direction (18).Electric machine according to one of Claims 1 to 5, characterized in that the shaft (10) is of continuously variable configuration at least in one region of the lamination stack (6).Electric machine according to one of Claims 1 to 6, characterized in that the resilient shoulder (3) has a decreasing stiffness in an inwardly directed, radial direction (34).Electric machine according to claim 7, characterised in that the resilient shoulder (3) has a decreasing tangential width (41) in the inwardly directed radial direction (34).Electric machine according to Claim 8, characterized in that the resilient shoulder (3) has a material thickness which decreases at least in sections in the inwardly directed, radial direction (34).Electric machine according to one of Claims 7 to 9, characterized in that the resilient shoulder (3) is bent over in an at least substantially uniformly curved manner towards the shaft (10).Electric machine according to one of Claims 1 to 10, characterized in that a tangential position of resilient shoulders (3, 3E, 3F), which are arranged at least substantially one behind the other, of a plurality of plates (5, 5E, 5F) varies.Electric machine according to one of Claims 1 to 11, characterized in that a form fit is formed between the lamination stack (6) and the shaft (10) in a circumferential direction (55).Electric machine according to Claim 12, characterized in that the form-fit formed in the circumferential direction (55) is formed between a lamination (5) of the lamination stack (6) and the shaft (10).Electric machine according to one of Claims 1 to 13, characterized in that the shaft (10) has at least one recess (54), and in that the resilient shoulder (3) of the plate (5) of the plate pack (6) engages at least partially in the recess (54) of the shaft (10) in order to form a positive fit in a circumferential direction (55).Electric machine according to Claim 14, characterized in that the recess (54) is formed by a groove provided in the shaft and running in an axial direction (18).Electric machine (8), in particular an electric motor, having a stator (15) and at least one housing part (16), wherein the stator (15) has a lamination stack (6) having a plurality of laminations (5) and wherein the stator (15) is connected at least indirectly to the housing part (16), characterized in that at least one resilient shoulder (3) is formed on at least one lamination (5), said resilient shoulder serving at least for an indirect fastening of the lamination stack (6) to the housing part (16), and a centring shoulder (1) is formed on the lamination (5) and / or on at least one further lamination (5), said centring shoulder serving for at least substantially radial centring of the lamination stack (6) relative to a shaft (10), wherein the centring shoulder (1) is designed with a clearance or transition fit towards the housing part (16).Electric machine according to Claim 16, characterized in that the resilient shoulder (3) is of nose-shaped design.Electric machine according to Claim 16 or 17, characterized in that the resilient shoulder (3) is prestressed at least in a radial direction (18), and the lamination stack is thereby fixed in a force-fitting manner in the housing part (16).Electric machine according to Claim 18, characterized in that a form-fitting connection is formed between the housing part (16) and the resilient shoulder (3).Electric machine according to one of Claims 16 to 20, characterized in that resilient attachments (3) are formed on a plurality of laminations (5) of the lamination stack (6), and in that a free space (19) is provided behind a resilient attachment (3) at least in an axial direction (18).Electric machine according to one of Claims 16 to 20, characterized in that an inner surface (25) of the housing part (16) is of continuously variable configuration at least in a region of the lamination stack (6).Electric machine according to one of Claims 16 to 21, characterized in that the resilient shoulder (3) has a decreasing stiffness in an outward, radial direction (34').Electric machine according to claim 22, characterised in that the resilient shoulder (3) has a decreasing tangential width (41) in the outward radial direction (34').Electric machine according to Claim 22, characterized in that the resilient shoulder (3) has a material thickness which decreases at least in sections in the outward-directed, radial direction (34').Electric machine according to one of Claims 22 to 24, characterized in that the resilient shoulder (3) is bent over in an at least substantially uniformly curved manner towards the housing part (16).Electric machine according to one of Claims 16 to 25, characterized in that a tangential position of resilient shoulders (3, 3E, 3F), which are arranged at least substantially one behind the other, of a plurality of plates (5, 5E, 5F) varies.Electric machine according to one of Claims 16 to 26, characterized in that a form fit is formed between the lamination stack (6) of the stator (15) and the housing part (16) in a circumferential direction (55).Electric machine according to Claim 27, characterized in that the form-fit formed in the circumferential direction (55) is formed between at least one lamination (5) of the lamination stack (6) and the housing part (16).Electric machine according to one of Claims 16 to 28, characterized in that the housing part (16) has at least one recess (54), and in that the resilient shoulder (3) of the lamella (5) of the lamella pack (6) engages at least partially in the recess (54) of the housing part (16) in order to form a positive fit in a circumferential direction (55).Electric machine according to Claim 29, characterized in that the recess (54) is formed by a groove which is provided in the housing part (16) and runs in an axial direction (18).

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