Rotor shaft for an electric machine and electric machine

Abstract

A rotor shaft for an electric machine includes a rotor shaft main body and a rotor shaft core which is arranged therein and which is connected to the rotor shaft main body. The rotor shaft comprises a substantially axially running cooling cavity configured to conduct a cooling fluid, and the rotor shaft core is composed of a different material than the rotor shaft main body.

Claims

1. A rotor shaft for an electric machine, the rotor shaft comprising: a rotor shaft main body; and a rotor shaft core which is arranged in the rotor shaft main body and which is connected to the rotor shaft main body along an entire length of the rotor shaft core, wherein the rotor shaft comprises a substantially axially running cooling cavity configured to conduct a cooling fluid, wherein the rotor shaft core is composed of a different material than the rotor shaft main body, wherein the rotor shaft comprises at least one axially continuous air channel that runs partially in the rotor shaft main body and partially in the rotor shaft core, wherein the rotor shaft comprises a plurality of air channels that are circumferentially uniformly distributed and arranged, in each case, with an identical radial spacing around the cooling cavity.

2. The rotor shaft according to claim 1, wherein a cooling fluid lance is arranged in the cooling cavity.

3. The rotor shaft according to claim 2, wherein a cooling fluid diverting piece is further arranged in the cooling cavity.

4. The rotor shaft according to claim 2, wherein the cooling cavity runs substantially centrally and in continuous fashion in the rotor shaft.

5. The rotor shaft according to claim 2, wherein the cooling cavity runs partially in the rotor shaft main body and partially in the rotor shaft core.

6. The rotor shaft according to claim 1, wherein the rotor shaft core is introduced as a solid body into the rotor shaft main body.

7. The rotor shaft according to claim 6, wherein the rotor shaft main body comprises two parts connected to one another after the introduction of the rotor shaft core.

8. The rotor shaft according to claim 1, wherein the rotor shaft core is produced from an aluminum material, a magnesium material and/or a plastic, and the rotor shaft main body is produced from a steel material.

9. The rotor shaft according to claim 1, wherein the cooling cavity runs substantially centrally and in continuous fashion in the rotor shaft.

10. The rotor shaft according to claim 1, wherein the cooling cavity runs partially in the rotor shaft main body and partially in the rotor shaft core.

11. The rotor shaft according to claim 1, wherein the rotor shaft core is spaced apart axially from a first and/or a second rotor shaft end.

12. The rotor shaft according to claim 1, wherein the rotor shaft core is introduced by a casting process into the rotor shaft main body.

13. The rotor shaft according to claim 1, wherein the axially continuous air channel is produced by drilling and/or erosion.

14. The rotor shaft according to claim 1, wherein the axially continuous air channel encloses an acute angle with a rotor shaft axis.

15. A rotor shaft for an electric machine, the rotor shaft comprising: a rotor shaft main body; and a rotor shaft core which is arranged therein and which is connected to the rotor shaft main body, wherein the rotor shaft comprises a substantially axially running cooling cavity configured to conduct a cooling fluid, wherein the rotor shaft core is composed of a different material than the rotor shaft main body, wherein the rotor shaft comprises at least one axially continuous air channel, wherein the rotor shaft comprises a plurality of air channels that are circumferentially uniformly distributed and arranged, in each case, with an identical radial spacing around the cooling cavity.

16. An electric machine having a rotor shaft, the rotor shaft comprising: a rotor shaft main body; and a rotor shaft core which is arranged in the rotor shaft main body and which is connected to the rotor shaft main body along an entire length of the rotor shaft core, wherein the rotor shaft comprises a substantially axially running cooling cavity configured to conduct a cooling fluid, wherein the rotor shaft core is composed of a different material than the rotor shaft main body, wherein the rotor shaft comprises at least one axially continuous air channel, wherein the rotor shaft comprises a plurality of air channels that are circumferentially uniformly distributed and arranged, in each case, with an identical radial spacing around the cooling cavity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically shows a rotor shaft according to the invention of an electric machine according to the invention according to a first embodiment.

(2) FIG. 2 schematically shows a rotor shaft according to the invention of an electric machine according to the invention according to a second embodiment.

(3) FIG. 3 schematically shows a rotor shaft according to the invention of an electric machine according to the invention according to a third embodiment.

(4) FIG. 4 schematically shows a cross section along the line IV-IV from FIG. 1 and FIG. 2, in which, for clarity, only one rotor shaft main body and one rotor shaft core are shown.

(5) FIG. 5 schematically shows a cross section of a rotor shaft according to the invention of an electric machine according to the invention according to a second embodiment of the cross section.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) FIG. 1 shows a rotor shaft 10 for an electric machine (not illustrated in any more detail), wherein the rotor shaft 10 comprises a rotor shaft main body 12 and a rotor shaft core 14 which is arranged in the rotor shaft main body 12 and which is connected to the rotor shaft main body 12.

(7) Furthermore, a cooling cavity 16 is arranged in the rotor shaft 10, which cooling cavity is a central, substantially axial bore in the embodiment illustrated.

(8) A cooling fluid lance 18 is inserted into the cooling cavity 16, via which cooling fluid lance a cooling fluid 20 is introduced into the cooling cavity 16. Here, the introduction direction is illustrated by an arrow 22.

(9) The cooling cavity 16 runs basically continuously in the rotor shaft 10, but is delimited at the end averted from the cooling fluid lance 18 by a cooling fluid diverting piece 24. Said cooling fluid diverting piece diverts the cooling fluid 20, as symbolized by the arrows 26, such that said cooling fluid emerges from the cooling cavity 16 again on the same side of the rotor shaft 10 at which it was introduced into the cooling cavity 16 (see arrow 22). The emergence is symbolized by the arrows 28.

(10) The result is thus a continuous flow of the cooling fluid 20 through the cooling cavity 16.

(11) Viewing the cooling cavity 16 from the side at which the cooling fluid 20 enters it, the cooling cavity 16 runs firstly in the rotor shaft main body 12 and then in the rotor shaft core 14.

(12) Here, the rotor shaft core 14 is spaced apart from a first and/or a second rotor shaft end. Said rotor shaft core is thus situated centrally in the rotor shaft 10 in an axial direction too.

(13) The rotor shaft core 14 is produced from a different material than the rotor shaft main body 12. For example, the rotor shaft core 14 is composed of an aluminum material and the rotor shaft main body 12 is composed of a steel material.

(14) Here, the production of the rotor shaft 10 is performed as follows: firstly, the rotor shaft main body 12 is manufactured. The rotor shaft core 14 is subsequently cast in liquid form into the space provided for it in the rotor shaft main body 12. Subsequently, that is to say after the rotor shaft 14 has solidified, the cooling cavity 16 is produced by cutting machining.

(15) The second embodiment, illustrated in FIG. 2, of the rotor shaft 10 differs from the embodiment as per FIG. 1 by the fact that the rotor shaft main body 12 is formed in two parts.

(16) In this embodiment, to produce the rotor shaft, firstly the two rotor shaft main body parts 12a and 12b are produced, wherein, in the embodiment illustrated, the rotor shaft main body part 12a is formed as a rotor shaft primary body and the rotor shaft main body part 12b is formed as a rotor shaft end piece.

(17) In this embodiment, the rotor shaft core 14 is positioned as a solid body in the space provided in the rotor shaft main body part 12a. Then, the two rotor shaft main body parts 12a and 12b are connected to one another, for example by welding.

(18) The other features of the rotor shaft 10 from FIG. 2 correspond to those from FIG. 1, to which reference is made at this juncture.

(19) FIG. 3 shows a further embodiment of the rotor shaft 10. This differs from the embodiments mentioned above in that the rotor shaft 10 comprises an axially continuous air channel 30a and an axially continuous air channel 30b.

(20) Here, the two air channels 30a, 30b run partially in the rotor shaft main body 12 and partially in the rotor shaft core 14 and are produced by drilling and/or erosion.

(21) Here, the air channel 30a runs substantially parallel to a rotor shaft axis 32.

(22) The air channel 30b encloses an acute angle α with the rotor shaft axis 32.

(23) Here, it is also conceivable for the rotor shaft 10 to comprise only a single air channel, which is then either of the type of the air channel 30a or of the type of the air channel 30b.

(24) The rotor shaft 10 may also comprise multiple air channels.

(25) In this regard, by way of example, FIG. 5 shows a cross section of a rotor shaft 10 which has eight air channels 30c to 30j. For the sake of clarity, neither the cooling fluid lance 18 nor the cooling fluid 20 are illustrated in this cross section.

(26) The air channels 30c to 30j are arranged so as to be circumferentially uniformly distributed in the rotor shaft 10 and have each case an identical radial spacing to the cooling cavity 16.

(27) If the rotor shaft 10 is set in rotational motion, air can flow through the air channels 30a to 30j. Air cooling of the rotor shaft 10 is thus realized. The air flow is symbolized by the arrows 34.

(28) For the other features of the rotor shaft 10 according to the third embodiment, reference is made to the statements relating to FIGS. 1 and 2.

(29) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.