Rotor Shaft of an Electric Motor

Abstract

A rotor shaft of an electric motor, in particular of an electrically excited synchronous machine, is composed of a shaft body and a power transmission module, the shaft body having a tubular open end that faces the power transmission module and forms a seat in which an end of the power transmission module located closer to the shaft body is interlockingly accommodated in the seat.

Claims

1.-10. (canceled)

11. A rotor shaft of an electric motor, the rotor shaft comprising: a shaft body; and a current transmission module, wherein: the shaft body has a tubular open end which is directed toward the current transmission module and forms a receptacle, and a shaft body-side end of the current transmission module is received in the receptacle in a positively locking manner.

12. The rotor shaft according to claim 11, wherein the electric motor is an energized synchronous machine.

13. The rotor shaft according to claim 11, wherein: the shaft body-side end of the current transmission module has an axial projection which ends in a circumferential shoulder, and the shaft body-side end of the current transmission module protrudes into the receptacle at an end of the shaft body to such an extent that the shoulder bears against an end face of the shaft body.

14. The rotor shaft according to claim 11, wherein the current transmission module comprises a main body which is made from a first material and on which electric contact elements which are made from a second material are provided.

15. The rotor shaft according to claim 14, wherein the first material is a material of the shaft body.

16. The rotor shaft according to claim 14, wherein the main body comprises a cavity in an interior of the main body, and the cavity is closed off with respect to an interior space of the shaft body.

17. The rotor shaft according to claim 16, wherein the electric contact elements comprise conductor tracks which run on an inner side of the cavity in the main body.

18. The rotor shaft according to claim 14, wherein the electric contact elements comprise conductor tracks which run in contact channels which are provided in the main body, and which are connected in an electrically conducting manner to contact points which are arranged on an outer side of the main body.

19. The rotor shaft according to claim 14, wherein two contact rings are arranged on an outer side of the current transmission module at an end of the current transmission module which faces away from the shaft body.

20. The rotor shaft according to claim 18, wherein cooling fluid channels are provided in the current transmission module, and the cooling fluid channels emanate from the shaft body-side end, open on a circumferential face of the current transmission module, and are connected fluidically to an interior space of the shaft body.

21. The rotor shaft according to claim 20, wherein the cooling fluid channels are provided in a main body of the current transmission module.

22. The rotor shaft according to claim 20, wherein the cooling fluid channels are arranged offset in a circumferential direction with respect to the contact channels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows a diagrammatic exploded illustration of a rotor of an energized synchronous machine.

[0027] FIG. 2 shows a diagrammatic sectional view of a rotor shaft according to an embodiment of the invention.

[0028] FIG. 3 shows a diagrammatic perspective illustration of a shaft body of the rotor shaft from FIG. 2.

[0029] FIG. 4 shows a diagrammatic perspective illustration of a current transmission module of the rotor shaft from FIG. 2.

[0030] FIG. 5 shows a diagrammatic enlarged sectional view of the transition from the shaft body to the current generation module of the rotor shaft from FIG. 2.

[0031] FIGS. 6 and 7 show diagrammatic perspective sectional views of the current transmission module from FIG. 4.

DETAILED DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 shows an outline sketch of a rotor 10 of an energized synchronous machine (not shown in greater detail). A rotor shaft 12 extends through the entire rotor 10, and serves both for mounting and transmission of the output power, and for the current supply of rotor windings 16 which are received on a carrier 14 and usually consist of a copper wire.

[0033] Electric connectors (conventionally in the form of two contact rings 18 at an axial end of the rotor shaft 12) are in electric contact with an external current source (not shown). Electric current is transmitted, for example, via brushes in contact with the contact rings 18 to the rotor windings 16.

[0034] FIGS. 2 to 7 show a rotor shaft 12 according to an embodiment of the invention.

[0035] The rotor shaft 12 is composed of two individual, separately prefabricated components, namely a shaft body 20 and a current transmission module 22 which are arranged behind one another in the axial direction A along the longitudinal extent of the rotor shaft 12.

[0036] That end of the shaft body 20 which is directed toward the current transmission module 22 is of tubular and open design, and ends in an annular end face 24 (see, for example, FIG. 3). This open end forms a receptacle 26 with a substantially cylindrical inner wall.

[0037] In this example, the receptacle 26 merges without a change in the internal diameter of the shaft body 20 into a hollow interior space 28 of the shaft body, which hollow interior space 28 extends in the axial direction A through the entire shaft body 20.

[0038] In this example, the shaft body 20 has substantially the same external diameter over its entire longitudinal extent.

[0039] At that end which lies opposite the receptacle 26, a toothing system 30 is configured on an inner face of the shaft body, by way of which toothing system 30 an output shaft can be coupled to the rotor shaft 12.

[0040] At its shaft body-side end 32, the current transmission module 22 has a cylindrical (circular-cylindrical here) projection 34, the diameter and outer contour of which are adapted to the diameter and the inner contour of the receptacle 26. The projection 34 is delimited in the axial direction A by way of a shoulder 38.

[0041] In the case of the manufacture of the rotor shaft 12, the shaft body 20 is pressed onto the shaft body-side end 32 of the current transmission module 22 in such a way that the projection 34 is arranged completely in the interior of the receptacle 26 in the finished rotor shaft 12, and the shoulder 38 bears against the end face 24 of the shaft body 20.

[0042] A plurality of grooves which run in the axial direction A are provided on the outer circumferential face of the projection 34, which grooves form cooling fluid channels 40 and, at the shaft body-side end 32 of the current transmission module 22, are connected fluidically to the interior space 28 of the shaft body 20. This is shown in FIGS. 2 and 6.

[0043] With the exception of the cooling fluid channels 40, the outer circumferential face of the projection 34 bears flatly and in a positively locking manner against the inner side of the receptacle 26 of the shaft body 20. This can be seen, for example, in FIG. 5.

[0044] The cooling fluid channels 40 run partially as closed channels in the current transmission module 22 until they open into outlet points 42 on the outer circumferential face of the current transmission module 22 in a manner which is remote in the axial direction A from the shaft body-side end 32.

[0045] Cooling fluid from the interior space 28 of the shaft body 20 can thus flow through the cooling fluid channels 40 along the projection 34 of the current transmission module 22 as far as the outlet points 42, and can thus cool the current transmission module 22.

[0046] The current transmission module 22 has a rigid, dimensionally stable main body 44 which consists of the same material here as the shaft body 20.

[0047] A cavity 46 is provided in the interior of the main body 44, which cavity 46 is closed off in a fluid-tight manner with respect to the interior space 28 of the shaft body 20, here by way of an end wall 47 which separates the cavity 46 from the interior space 28. The cooling fluid channels 40 do not establish a fluidic connection to the cavity 46 either, with the result that the cavity 46 always remains free of coolant.

[0048] Electric contact elements 48 are arranged on the main body 44, which electric contact elements 48 consist of a second, electrically satisfactorily conductive material which is different than the first material of the main body 44, such as copper, for example.

[0049] In this example, that end 50 of the main body 44 which is remote from the shaft body is open toward the cavity 46. The second material is applied to the main body 44 in the form of a plurality of conductor tracks 52 which run from the outer circumferential face of the main body 44 via the open end and on the inner wall of the cavity 46 as far as contact channels 54 which are configured in the main body 44 (see FIGS. 5 and 7), and through these contact channels 54 radially to the outside to in each case one contact point 56 on a circumferential face of the main body 44. The contact points 56 are spaced apart in the axial direction A from the end 50 which is remote from the shaft body.

[0050] Here, in each case one electric contact element 48 is connected electrically to a contact ring 18 at that end 50 of the main body 44 which is remote from the shaft body, for example by the contact rings 18 being pressed onto the end 50 and the electric contact elements 48 which are arranged there.

[0051] The contact rings 18 can consist of a different material than the second material, which different material possibly has a higher mechanical wear resistance if it is provided that the contact rings 18 are contacted by way of brushes.

[0052] The electric contact elements 48, the conductor tracks 52, the contact channels 54 and the contact points 56 are configured and arranged in such a way that two separate electric lines run from in each case one contact ring 18 to a contact point 56. The two contact points 56 are connected to the rotor windings 16 in the finished rotor 10, and serve for the current supply of the rotor windings 16. The two electric lines are of course insulated electrically from one another over their course, in order for it to be possible to establish a closed current circuit which is free from short-circuits via the two contact rings 18 and the rotor windings 16.

[0053] It goes without saying that further electric contact elements 48, conductor tracks 52, contact channels 54 and contact points 56 might be provided, in order to realize further electric lines for other purposes.

[0054] The contact channels 54 can be filled completely with the second material of the electric contact elements 48 from the contact points 56 as far as into the cavity 46.

[0055] It is possible for suitably shaped depressions or grooves which are filled with the second material to be provided in the region of the electric contact elements 48, in particular on the inner side of the cavity 46.

[0056] The contact channels 54 and the contact points 56 are offset along the circumference of the main body 44 with respect to the cooling fluid channels 40 and their outlet points 42, and do not have any overlaps.

[0057] The main body 44 can be manufactured in any suitable way, for example by way of a casting method, possibly combined with drilling and/or milling steps, in order to manufacture the cooling fluid channels 40, the contact channels 54 and other geometric elements.

[0058] In this example, the rotor shaft 12 is mounted in the region of the current transmission module 22 (see bearing 60 in FIG. 5). To this end, it can be provided that the main body 44 of the current transmission module 22 tapers in an axial direction A adjacently with respect to the shoulder 38, with the result that the end 50 of the current transmission module 22 can be pushed into the bearing 60.