ROTOR, ELECTRIC MOTOR, METHOD FOR PRODUCING A ROTOR AND USE OF A ROTOR AND ELECTRIC MOTOR

Abstract

A rotor and a method of making such a rotor, wherein the rotor has a shaft, a longitudinal axis, and a rotor packet connected to the shaft at least in torsion-resistant manner. The rotor packet is assembled from individual sheet lamellae, wherein the rotor packet has an opening for receiving the shaft. The shaft is a hollow shaft with a wall, wherein the wall of the shaft has, on its side facing toward the opening, recesses extending in the longitudinal direction. An electric motor, in particular a synchronous or hybrid synchronous machine, including a rotor and a stator, has such a rotor. The recesses are produced by cutting methods, in particular milling, or reshaping methods, in particular pressing.

Claims

1.-15. (canceled)

16. A rotor, comprising a shaft with a longitudinal axis, and a rotor packet connected to the shaft at least in a torsion-resistant manner, wherein the rotor packet comprises individual sheet lamellae, wherein the rotor packet comprises an opening sized and shaped to receive the shaft, wherein the shaft is a hollow shaft with a wall, wherein the wall of the shaft comprises, on its side facing toward the opening, recesses extending in the longitudinal direction.

17. The rotor of claim 16 wherein the recesses are oriented parallel to the longitudinal axis of the shaft and/or parallel to one another.

18. The rotor of claim 16 wherein each of the recesses is an elongated hole in the wall of the shaft.

19. The rotor of claim 18 wherein each elongated hole extends over a portion of the shaft.

20. The rotor of claim 16 wherein each of the recesses is configured as a groove.

21. The rotor of claim 16 wherein the shaft comprises contact faces that lie against the inner surface of the opening, individual ones of the recesses being arranged between respective contact faces.

22. The rotor of claim 16 wherein the shaft is formed from a magnetically soft material.

23. The rotor of claim 16 wherein the rotor packet exhibits cutouts which directly adjoin the recesses so that the recesses and cutouts jointly form a contiguous flux barrier in each instance.

24. An electric motor comprising a rotor and a stator, wherein the rotor comprises a shaft with a longitudinal axis and a rotor packet connected to the shaft at least in a torsion-resistant manner, wherein the rotor packet comprises individual sheet lamellae, wherein the rotor packet comprises an opening sized and shaped to receive the shaft, and wherein the shaft is a hollow shaft with a wall, wherein the wall of the shaft comprises, on its side facing toward the opening, recesses extending in the longitudinal direction.

25. A method for producing a rotor, the rotor comprising a shaft with a longitudinal axis and a rotor packet connected to the shaft at least in a torsion-resistant manner, wherein the rotor packet comprises individual sheet lamellae, wherein the rotor packet comprises an opening sized and shaped to receive the shaft, and wherein the shaft is a hollow shaft with a wall, wherein the wall of the shaft comprises, on its side facing toward the opening, recesses extending in the longitudinal direction, the method comprising: producing the recesses by material-separating methods or reshaping methods.

Description

[0028] Further features and advantages of the present invention will become clear on the basis of the following description of preferred embodiment examples with reference to the appended images. Shown therein are:

[0029] FIG. 1 an electric motor according to the invention with a rotor according to the invention, in a schematic cross-sectional representation;

[0030] FIG. 2a a shaft of a rotor according to the invention, in a perspective representation;

[0031] FIG. 2b a shaft of a rotor according to the invention, in a top view;

[0032] FIG. 3 a rotor according to the invention, in a perspective representation;

[0033] FIG. 4 a rotor according to the invention, in a view from the front;

[0034] FIG. 5 an exemplary comparison of the transmissible torque as a function of speed for various rotor-packet/shaft constellations;

[0035] FIG. 6a a further embodiment of a shaft for a rotor according to the invention, in a first perspective representation;

[0036] FIG. 6b an embodiment of a shaft according to FIG. 6a for a rotor according to the invention, in another perspective representation;

[0037] FIG. 7 a rotor according to the invention with a shaft according to FIG. 6a or 6b, in a perspective representation;

[0038] FIG. 8 a schematic representation of lines of magnetic flux in a rotor according to the invention;

[0039] FIG. 9 a schematic representation of lines of magnetic flux in a rotor according to the invention.

[0040] Reference will firstly be made to FIG. 1.

[0041] A rotor R according to the invention substantially comprises a shaft 1 and a rotor packet 2.

[0042] The rotor packet 2 is mounted on the shaft 1 in torsion-resistant manner, but preferentially also in axially fixed manner.

[0043] The shaft 1 is a hollow shaft with a corresponding wall 11. The shaft 1 has a corresponding longitudinal axis or axis of rotation L.

[0044] The rotor packet 2 exhibits at least one, preferentially several, annular sheet lamellae 21 which have been assembled to form a hollow cylindrical rotor packet 2. Correspondingly, the sheet lamellae 21 have been lined up in series in the axial direction. But the sheet lamellae 21 as such may also have been assembled from individual sheet-lamella segments (not represented) which have been arranged and connected in series in the peripheral direction.

[0045] The rotor packet 2 exhibits an opening 22, through which the shaft 1 has been passed or in which the shaft 1 is received. This opening 22 exhibits a surface facing toward the shaft, which will be designated below as the inner surface.

[0046] The shaft 1 or the wall 11 thereof exhibits correspondingly a surface facing toward the opening 22.

[0047] In accordance with the invention there is provision that the surface of the shaft 1 facing toward the inner surface of the opening 22 has been provided with recesses 12 extending in the longitudinal direction L. The recesses 12 are preferentially oriented parallel to the longitudinal axis L of the shaft 1 and/or parallel to one another.

[0048] In a first embodiment, which, for instance, is represented in the images FIG. 6, the recesses 12 may have been configured as elongated holes in the wall 11 of the hollow shaft. The elongated hole 12 preferentially penetrates the wall 11 completely and is preferentially produced by material-separating methods such as milling or punching, for instance. To this extent, the recesses 12 of this embodiment preferentially do not extend over the entire length of the shaft 1 but, as a rule, extend over the part of the shaft 1 that is located in the opening 22 of the rotor packet 2. Alternatively, there may also be provision that the elongated holes 12 are open on one side. All the one-sided openings of the elongated holes may have been arranged on one side of the shaft 1 but may also have been arranged in alternating manner or in a pattern alternating with respect to the side of the shaft 1.

[0049] In a further embodiment, the wall 11 may have been configured in profiled manner—that is to say, the recesses 12 have been configured as grooves. The groove 12 correspondingly exhibits a groove bottom—that is to say, in contrast to the elongated holes the groove 12 does not penetrate the wall 11 completely. The groove or the profiling is preferentially produced by means of reshaping methods such as pressing, for instance.

[0050] In both embodiments, contact faces 13 between the recesses 12 of the shaft 1 ultimately result that lie against the inner surface of the opening 22. These contact faces 13 are preferentially separated from one another in the peripheral direction by the recesses 12.

[0051] As a result, a rotor shaft 1 having reduced peripheral rigidity is proposed, onto which a rotor packet 2 has been directly pressed. The reduction of the peripheral rigidity can be effected by virtue of recesses 12, for instance in the form of elongated holes and/or grooves which have been introduced.

[0052] For the purpose of clarifying this effect, transmissible torque has been plotted over rotor speed in FIG. 5 in respect of various examples. Numeral I refers to an unprofiled hollow shaft; numeral II refers to a hollow shaft with four grooves as recesses; and numeral III refers to a hollow shaft with eight grooves as recesses (FIGS. 2 to 4).

[0053] In a further development of the invention, or with regard to an advantageous use, the recesses 12 may at the same time be utilized as flux barriers for directing a magnetic field, especially in the case of synchronous or hybrid synchronous machines. The number of recesses 12 advantageously amounts to an integral multiple n (n=1,2,3 . . . ) of the number of poles. For the purpose of Illustrating this effect, lines of magnetic flux 3 and the recesses 12 acting as flux barrier 4 are represented in FIG. 8 (with equal numbers of poles and recesses—that is to say, n=1) and FIG. 9 (with twice the number of recesses—that is to say, n=2).

[0054] For this purpose the shaft 1 has been formed from magnetically soft material, so that a magnetic path leads through one or more elevations 13 of the shaft. By this means, the shaft short-circuits, in each instance, two poles of two magnets 16. By the shaft 1 being utilized also as a magnetic conductor, material in the rotor packet 2 can be eliminated.

[0055] The rotor packet exhibits further flux barriers in the form of cutouts 15—here, substantially triangular cutouts 15. These cutouts 15 directly adjoin the recesses 12, so that the recesses 12 and cutouts 15 jointly form a contiguous flux barrier 4 in each instance. As a result, the magnetic material can be utilized more effectively, and material in the rotor packet 2 can be eliminated. In particular, regions radially below magnets 16 that are sparsely utilized magnetically have been cut out, so that the weight of the rotor can be reduced.

[0056] In a further development of the invention, or with regard to an advantageous use, the recesses 12 may also serve as ducts for a cooling medium which may come into direct contact with the rotor packet.

[0057] Features and details that have been described in connection with the method also apply, of course, in connection with the rotor or electric motor according to the invention, and conversely, so that, with respect to the disclosure, reference to the individual aspects of the invention is always made or can always be made reciprocally. In addition, the method according to the invention can be carried out with the rotor or electric motor according to the invention.

[0058] The following reference symbols are used in the images: [0059] S stator [0060] R rotor [0061] L longitudinal axis/axis of rotation [0062] 1 shaft [0063] 2 rotor packet [0064] 3 lines of magnetic flux [0065] 4 flux barrier [0066] 11 wall/surface [0067] 12 recess [0068] 13 contact face [0069] 15 cutout [0070] 16 magnet [0071] 21 sheet lamellae [0072] 22 opening/inner surface