Electric motor

Abstract

An electric motor having a rotatably mounted rotor shaft onto which a laminated rotor core is plugged, the laminated rotor core having a stack of individual laminations, wherein each individual lamination has first cutouts, and radial recesses are formed on the inner circumference of each individual lamination.

Description

[0001] electric motor

[0002] Description:

[0003] The invention relates to an electric motor.

[0004] It is generally known that an electric motor has a rotatably mounted rotor.

[0005] From WO 2023 / 102 587 A1, a rotor is known as the closest state of the art.

[0006] A rotor is also known from CN 2 07 801 597 U.

[0007] From EP 2 912 754 B1 a stack of metal sheets for mounting over a cylindrical part is known.

[0008] An electrical machine is known from DE 102009 047 485 A1.

[0009] From DE 199 15 664 A1 an electric machine with a stator is known.

[0010] A method for manufacturing a rotor is known from DE 102013206 045 A1.

[0011] The invention is therefore based on the objective of further developing an electric motor device and a method, wherein

[0012] According to the invention, the task of making the electric motor simple and highly precise to manufacture is made possible.

[0013] Important features of the invention in the electric motor are that the electric motor has a rotatably mounted rotor shaft onto which a rotor lamination stack is mounted, wherein the rotor lamination stack comprises a stack of individual laminations, in particular wherein the stacking direction of the stack is aligned parallel to the axis of rotation of the rotor shaft, wherein the respective individual lamination has first recesses, wherein radial recesses are formed on the inner circumference of the respective individual lamination, in particular such that the inner circumference in the area covered by the radial recesses in the circumferential direction is radially spaced from the rotor shaft and / or such that the inner circumference in the area covered by the radial recesses in the circumferential direction has an inner radius that is larger than the outer radius of the rotor shaft.

[0014] An advantage of this design is that the rotor lamination stack rests on the rotor shaft at only a few circumferential points, where it is elastically designed by means of recesses and cutouts. Due to this elastic design, the rotor lamination stack centers itself on the rotor shaft when fitted, resulting in a highly precise arrangement and design.

[0015] In an advantageous embodiment, the inner radius of each individual sheet, within the area covered by the respective radial reduction in the circumferential direction, particularly the circumferential angle range, follows a Gaussian function and / or a Gaussian bell curve as a function of the circumferential angle. The advantage here is that a high load-bearing capacity of the material can be achieved without material failure.

[0016] In an advantageous embodiment, the inner radius of each individual sheet metal follows a rectangular function in the area covered by the respective radial recess in the circumferential direction, particularly the circumferential angle area. The advantage here is that high elasticity can be achieved with minimal material being removed.

[0017] In an advantageous embodiment, the first recesses are spaced apart from each other circumferentially, in particular uniformly. It is advantageous that the rotor lamination stack or the individual lamination rests on the rotor shaft at several circumferential points, and each of these contact points is elastically designed by means of the first recesses, thus enabling highly accurate centering. In an advantageous embodiment, the radial recesses are spaced apart from each other circumferentially, in particular uniformly, with three radial recesses being formed on the inner circumference of the individual lamination. It is advantageous that contact points are formed between the recesses circumferentially, and thus the rotor lamination stack or the individual lamination rests on the rotor shaft at several circumferential points, and each of these contact points is elastically designed by means of the first recesses, thus enabling highly accurate centering.

[0018] In an advantageous embodiment, the first recesses extend further circumferentially than radially. This is advantageous because it allows for high elasticity in the radial direction, particularly in the area of ​​the respective contact point. The contact point is preferably located centrally to each first recess in the circumferential direction.

[0019] In an advantageous embodiment, the first recesses are all arranged at the same, and in particular identical, radial distance to the axis of rotation of the rotor shaft. It is advantageous that the recesses are all arranged at the same radial height, thus preventing the formation of circumferential transverse stresses in the material of the individual sheet.

[0020] In an advantageous embodiment, the radial width, in particular the slot width, of the first recesses is independent of the circumferential angle, particularly with the exception of the end region of the respective first recess located at the front in the circumferential direction and with the exception of the end region of the respective first exception located at the rear in the circumferential direction, in particular wherein the radial width decreases strictly monotonically in the respective end region. It is advantageous that the elasticity is distributed as uniformly as possible throughout the material of the individual sheet.

[0021] In an advantageous embodiment, the inner circumference of the individual sheet metal, in the area covered circumferentially by the first recess, has a smaller radius of curvature than the rotor shaft at its outer circumference, specifically such that the magnitude of the outer radius of the rotor shaft is greater than the magnitude of the inner radius of the individual sheet metal in the aforementioned area. It is advantageous that a gap is created between the individual sheet metal and the rotor shaft, into which elastic deflection of the individual sheet metal is permitted. The gap is bounded on both sides circumferentially, i.e., at the front and rear, by the contact points of the individual sheet metal on the rotor shaft.or that the inner circumference of the individual sheet in the area covered circumferentially by the first recess has a larger radius of curvature than the rotor shaft at its outer circumference, in particular such that the magnitude of the outer radius of the rotor shaft is smaller than the magnitude of the inner radius of the individual sheet, especially where the radius of curvature is infinitely large, i.e., the outer circumference has one or more straight segments. It is advantageous that the individual sheet rests on the rotor shaft in the area of ​​the larger radius of curvature and is spaced from the rotor shaft on both sides of this area in the circumferential direction.

[0022] In an advantageous embodiment, the radius of curvature is referenced to a circle center located on the line connecting the circumferential center of the first recess and the axis of rotation of the rotor shaft. An advantage of this is that several areas with such a radius of curvature can be formed on the inner circumference by using different circle centers. The circle centers themselves lie on a circle whose center is on the axis of rotation of the rotor shaft.

[0023] In an advantageous embodiment, each radial retraction is arranged centrally in the circumferential direction between two adjacent first recesses. An advantage of this design is that high elasticity can be achieved.

[0024] In a preferred embodiment, the inner circumference of the individual sheet is a polygon. This has the advantage of enabling simple manufacturing.

[0025] In an advantageous embodiment, the individual lamination has at least one circular hole. This is advantageous because it allows for a further increase in elasticity while still achieving high load-bearing capacity. Furthermore, relative alignment of the individual laminations of the rotor lamination stack with each other is easily accomplished.

[0026] In an advantageous embodiment, the area covered by the radial recess in the circumferential direction is contained within the area covered by the circular hole in the circumferential direction. An advantage of this is that, despite the high elasticity, mechanical stresses can be reduced.

[0027] In an advantageous embodiment, the circular hole is radially spaced from the radial recess. An advantage of this is that a high load-bearing capacity of the material is maintained.

[0028] In an advantageous embodiment, the area covered by the circular hole in the radial direction overlaps with the area covered by the first recess in the radial direction. It is advantageous that the circular hole can be positioned sufficiently close to the first recesses to achieve high elasticity.

[0029] In an advantageous embodiment, the area covered by the radial recess overlaps with the area covered by the first recess in the radial direction. It is advantageous that the recess can be positioned sufficiently close to the first recesses to achieve high elasticity.

[0030] In an advantageous embodiment, the individual sheet has second recesses which are slot-shaped, wherein the smallest radial distance of the respective second recess, measured to the axis of rotation of the rotor shaft, increases monotonically, in particular strictly monotonically, with an angular distance increasing in magnitude with respect to a respective circumferential position, wherein the width of the recess tapers, in particular so that with a larger radial distance the respective second recess has a smaller width, in particular wherein several, in particular four, such circumferential positions are present on the circumference of the individual sheet, in particular wherein a first row of second recesses is formed in the circumferential direction in front of the respective circumferential position and a second row of second recesses is formed in the circumferential direction behind the respective circumferential position, in particular wherein the second recesses of the respective row are spaced apart from each other.In particular, the second set of recesses becomes shorter along their direction of extension with increasing radial spacing. An advantage of this is that the elasticity of the individual sheet is increased, while power losses caused by field lines running through the material of the individual sheet are reduced.

[0031] Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0032] The invention will now be explained in more detail with reference to schematic illustrations:

[0033] Figure 1 schematically shows a cross-section through a rotor lamination stack of an electric motor according to the invention mounted on a rotor shaft 1, so that a squirrel cage and / or permanent magnets are not shown.

[0034] Figure 2 shows the cross-section without rotor shaft 1.

[0035] Figure 3 schematically shows a cross-section through another rotor lamination stack of a further electric motor according to the invention.

[0036] Figure 4 shows an enlarged area of ​​Figure 3.

[0037] As shown in Figure 1 and Figure 2, the rotor lamination stack, composed of individual laminations 2, is attached to the rotor shaft 1, in particular by thermal shrinking.

[0038] In particular, the rotor lamination stack is stamped from the individual laminations and preferably the individual laminations 5 are identical to each other, in particular all being structurally identical to each other.

[0039] The stacking direction is parallel to the axial direction, in particular parallel to the axis of rotation of the rotor shaft 1 of the electric motor. The radial and circumferential directions are also relative to the axis of rotation of the rotor shaft 1.

[0040] In order to achieve highly precise self-centering of the rotor lamination stack 1 to the rotor shaft 1 during installation, a three-point support on the rotor shaft 1 is provided on the inner circumference of each individual lamination 2.

[0041] For this purpose, radial recesses 6 are arranged at uniform intervals around the inner circumference of the individual lamination 2 of the rotor lamination stack, such that the inner radius is not a completely constant function of the circumferential angle but varies depending on the circumferential angle. In the region of the radial recesses 6, the inner radius is smaller than at circumferential angle positions between the area covered circumferentially by each radial recess 6. The behavior of the inner radius as a function of the circumferential angle in the area covered circumferentially by each radial recess 6 essentially corresponds to the behavior of a Gaussian function.

[0042] In particular, the radial recesses 6 are identical in shape to each other.

[0043] Each individual sheet 5 has recesses 5, each of which has a constant radial width and is spaced apart from the radial recesses 6.

[0044] Each recess 5 covers a radial spacing range that overlaps with the radial spacing range covered by the respective radial recess 6. However, the largest radial spacing of each recess 5 lies radially outside all radial recesses 6.

[0045] In the circumferential direction, the respective recess 5 covers an area which, at its circumferentially forward end, overlaps with or is circumferentially spaced from the area covered by a first radial recess 6.

[0046] In the circumferential direction, each recess 5 covers an area which, at its rear end in the circumferential direction, overlaps with or is spaced apart from the area covered by a second radial recess 6.

[0047] In this way, the respective recess 5 separates a respective inner web 3 of the single sheet, which extends radially inside the recess 5 in the circumferential direction, from a respective outer web 4 of the single sheet, which extends radially outside the recess 5 in the circumferential direction.

[0048] The respective recess 5 thus increases the elasticity, especially of the inner web 3.

[0049] If the inner radius of the individual sheet 2 at the inner web 3 were equal to the outer radius of the rotor shaft 1, the inner web 3 would be in contact with the rotor shaft 1 along its entire circumferential length. Preferably, however, the inner web 3 has a smaller inner radius relative to the rotor shaft 1 than the outer radius of the rotor shaft 1, at least within a circumferential angle range. This results in the inner web 3 being concavely curved in such a way that at least a slight distance between the individual sheet 2 and the rotor shaft 1 is created within this circumferential angle range. Adjacent to and / or adjacent to this circumferential angle range, the inner web is convexly curved, since the radial recess 6 begins or at least transitions into the respective radial recess 6 there. This means that, in the circumferential direction, the inner web only contacts the rotor shaft 1 at the respective two convex transition regions between any two adjacent radial recesses 6.

[0050] When placing the rotor lamination stack onto the rotor shaft 1, a high degree of elasticity can be used for the precise centering of the rotor lamination stack on the rotor shaft 1.

[0051] The electric motor can be designed as an asynchronous motor by passing a squirrel cage through the outer web 4, or as a synchronous motor by arranging permanent magnets in or on the outer web 4.

[0052] The radial distance always refers to the distance to the axis of rotation of rotor shaft 1. The axial direction is parallel to the axis of rotation. The circumferential direction is also relative to the axis of rotation of rotor shaft 1.

[0053] As shown in Figure 3 and Figure 4, in the further electric motor a plurality of recesses 5 are arranged at the same radial distance, which are spaced apart from each other in the circumferential direction.

[0054] Each of the recesses 5 is spaced apart from the radial inner edge of the respective individual sheet 2.

[0055] A radial recess 31, preferably designed as a rectangular groove, is formed on the radial inner edge. This radial recess 31 is preferably arranged radially within the recesses 5. The individual sheet 5 also has a continuous circular hole 30, wherein the area covered by this circular hole 30 in the circumferential direction comprises the area covered by the radial recess 31, in particular the rectangular groove, in the circumferential direction.

[0056] The single sheet 5 also has second recesses 32, the smallest radial spacing of which increases with increasing angular distance to a given circumferential position, with the width of the slot-shaped recess 32 tapering accordingly. Thus, a smaller width of the second recess 32 is provided for a larger radial spacing. The width is determined in particular as the slot width, specifically as the width measured perpendicular to the local direction of extension of the respective second recess 32.

[0057] Several, in particular four, circumferential positions are provided, which are evenly spaced from each other in the circumferential direction, in particular by 90°.

[0058] The second recesses 32, provided for each circumferential position, are arranged in a first row and a second row. Within the first row, the second recesses 32 are radially spaced apart from one another, and within the second row, the recesses 32 arranged in the second row are also radially spaced apart from one another. The first row is a mirror image of the second row with respect to the circumferential position. The first row extends circumferentially from the circumferential position, and the second row extends counter-circularly from the circumferential position.

[0059] In the circumferential direction, between each pair of circumferential positions, several, in particular four, spaced-apart recesses 5 are arranged at the same radial distance. Each of the recesses 5 extends further in the circumferential direction than in the radial direction.

[0060] The inner circumference of the individual sheet 33 has a larger radius of curvature in the area covered by the respective recess 5 in the circumferential direction than the outer radius of the rotor shaft 1. This is shown in Figure 4, where the second inner radius 42 is larger in magnitude than the outer radius of the rotor shaft 1. The inner radius 42 is a circular arc and refers to a circle center point located on the line connecting the center point of the recess 5 and the axis of rotation of the rotor shaft 1, i.e., the center point of the outer radius of the rotor shaft 1.

[0061] The first inner radius 41 of the single sheet 33, which adjoins the area with the second inner radius 42 on both sides in the circumferential direction, is preferably equal in magnitude to the second inner radius 42, but it refers to a circle center which lies on the connecting line between the center of the recess 5 nearest to the aforementioned recess 5 in the circumferential direction and the axis of rotation of the rotor shaft 1, i.e., the circle center of the outer radius of the rotor shaft 1.

[0062] Thus, the inner circumference of the single sheet 33 is composed of circular arcs, with the exception of the radial recesses 31.

[0063] The radial recesses 31, the circular holes 30 and the cutouts 5 improve elasticity to such an extent that highly precise alignment and centering of the rotor lamination stack is achieved when it is placed on the rotor shaft 1.

[0064] The rotor shaft 1 preferably touches the circular arcs centrally in the circumferential direction, so that the number of contact points on the inner circumference equals the number of recesses 5.

[0065] Preferably, the center point of each circular hole 30 is located in the circumferential direction between two mutually adjacent circumferential positions.

[0066] In further embodiments according to the invention, the Gaussian function is approximated by circular arc segments in order to enable simple manufacturing.

[0067] In further embodiments of the invention, the first inner radius 41 is realized by a straight segment, in particular by a circular arc with a very large radius of curvature, especially one tending towards infinity, and the second inner radius 42 is realized likewise. In this way, neglecting the radial recesses 31, the inner circumference of the individual sheet is a polygon. List of reference numerals

[0068] 1 Rotor shaft 2 Individual lamination of the rotor lamination stack

[0069] 3 inner web

[0070] 4 Outer walkway

[0071] 5 first exception

[0072] 6 radial return 30 circular hole

[0073] 31 radial retraction, in particular rectangular groove

[0074] 32 second exclusion

[0075] 33 individual laminations of the rotor lamination stack

[0076] 41 first inner radius 42 second inner radius

Claims

Patent claims:

1. Electric motor, wherein the electric motor has a rotatably mounted rotor shaft onto which a rotor lamination stack is mounted, wherein the rotor lamination stack comprises a stack of individual laminations, in particular wherein the stacking direction of the stack is aligned parallel to the axis of rotation of the rotor shaft, in particular wherein the rotor lamination stack is stamped from the individual laminations, in particular wherein the individual laminations are identical to each other, characterized in that the respective individual lamination has first recesses, wherein radial recesses (6, 31) are formed on the inner circumference of the respective individual lamination, in particular such that the inner circumference in the area covered by the radial recesses (6, 31) in the circumferential direction is radially spaced from the rotor shaft and / or such that the inner circumference in the area covered by the radial recesses (6, 31) in the circumferential direction has an inner radius which is larger than the outer radius of the rotor shaft.

2. Electric motor according to claim 1, characterized in that the inner radius of the respective individual sheet in the area covered by the respective radial retraction in the circumferential direction, in particular circumferential angle area, follows a Gaussian function and / or Gaussian bell curve as a function of the circumferential angle, or that the inner radius of the respective individual sheet in the area covered by the respective radial retraction in the circumferential direction, in particular circumferential angle area, follows a rectangular function.

3. Electric motor according to one of the preceding claims, characterized in that the first recesses are spaced apart from each other in the circumferential direction, in particular uniformly, and / or that the radial recesses are spaced apart from each other in the circumferential direction, in particular uniformly, in particular wherein three radial recesses are formed on the inner circumference of the single sheet.

4. Electric motor according to one of the preceding claims, characterized in that the first recesses extend further in the circumferential direction than in the radial direction and / or that the first recesses are all arranged at the same, in particular the same, radial distance to the axis of rotation of the rotor shaft.

5. Electric motor according to one of the preceding claims, characterized in that the radial width, in particular slot width, of the first recesses is independent of the circumferential angle, in particular with the exception of the end region of the respective first recess arranged at the front in the circumferential direction and with the exception of the end region of the respective first exception arranged at the rear in the circumferential direction, in particular wherein the radial width decreases strictly monotonically in the respective end region.

6. Electric motor according to one of the preceding claims, characterized in that the inner circumference of the individual sheet in the area covered in the circumferential direction by the first recess has a smaller radius of curvature than the rotor shaft at its outer circumference, in particular such that the magnitude of the outer radius of the rotor shaft is greater than the magnitude of the inner radius of the individual sheet, or that the inner circumference of the individual sheet in the area covered in the circumferential direction by the first recess has a larger radius of curvature than the rotor shaft at its outer circumference, in particular such that the magnitude of the outer radius of the rotor shaft is smaller than the magnitude of the inner radius of the individual sheet, in particular wherein the radius of curvature is infinitely large, i.e., the outer circumference has one or more straight segments.

7. Electric motor according to one of the preceding claims, characterized in that the radius of curvature is referred to a circle center which lies on the connecting line between the circumferentially viewed center of the first recess and the axis of rotation of the rotor shaft.

8. Electric motor according to one of the preceding claims, characterized in that the respective radial return is arranged centrally in the circumferential direction between two first recesses that are nearest to each other.

9. Electric motor according to one of the preceding claims, characterized in that the inner circumference of the single sheet is a polygon.

10. Electric motor according to one of the preceding claims, characterized in that the individual sheet metal has at least one circular hole.

11. Electric motor according to one of the preceding claims, characterized in that the area covered by the radial retraction in the circumferential direction is contained in the area covered by the circular hole in the circumferential direction.

12. Electric motor according to one of the preceding claims, characterized in that the circular hole is radially spaced from the radial return.

13. Electric motor according to one of the preceding claims, characterized in that the area covered by the circular hole in the radial direction overlaps with the area covered by the first recess in the radial direction.

14. Electric motor according to one of the preceding claims, characterized in that the area covered by the radial retraction in the radial direction overlaps with the area covered by the first recess in the radial direction.

15. Electric motor according to one of the preceding claims, characterized in that the single sheet has second recesses which are slot-shaped, wherein the smallest radial distance of the respective second recess, measured to the axis of rotation of the rotor shaft, increases monotonically, in particular strictly monotonically, with an angular distance increasing in magnitude with respect to a respective circumferential position, wherein the width of the recess tapers, in particular such that the respective second recess has a smaller width at a larger radial distance, in particular wherein several, in particular four, such circumferential positions are present on the circumference of the single sheet, in particular wherein a first row of second recesses is formed in the circumferential direction in front of the respective circumferential position and a second row of second recesses is formed in the circumferential direction behind the respective circumferential position.in particular wherein the second recesses of the respective row are spaced apart from each other, in particular wherein the second recesses extend for a shorter distance along their direction of extension with increasing radial spacing.

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