Multipart rotor shaft for an electric machine

1. A multipart rotor shaft for an electric machine, the multipart rotor shaft comprising:

a first shaft journal with a first end flange and with an axial passage bore;

a second shaft journal with a second end flange;

a hollow carrier for a laminated rotor core, wherein the carrier for the laminated rotor core is arranged between the first shaft journal and the second shaft journal and wherein the carrier, the first end flange and the second end flange delimit a cavity between them;

a line element for conducting a cooling medium, wherein the line element forms a cooling channel inside the cavity, and wherein the cooling channel is connected to the first axial passage bore, extends between the first shaft journal and the second shaft journal, and is connected to an outer part of the cavity which is formed between the carrier and the line element;

a separating element, wherein the separating element divides the outer part of the cavity into a first partial cavity on the side of the first shaft journal, and a second partial cavity on the side of the second shaft journal; and

an external pump which is arranged outside the rotor shaft and is configured to convey a cooling medium through the axial passage bore, the cooling channel, the first partial cavity and through the second partial cavity.

2. The multipart rotor shaft as claimed in claim 1 , wherein the first partial cavity is connected to the cooling channel via at least one first bore of the line element, and wherein the second partial cavity is connected to the cooling channel via at least one second bore of the line element.

3. The multipart rotor shaft as claimed in claim 1 , wherein the first end flange as at least one first opening for discharging cooling medium from the first partial cavity, and wherein the second end flange has at least one second opening for discharging cooling medium from the second partial cavity.

4. The multipart rotor shaft as claimed in claim 1 , wherein the separating element protrudes from the line element in the radial direction.

5. The multipart rotor shaft as claimed in claim 1 , wherein the separating element is integrally connected to the line element.

6. A multipart rotor shaft for an electric machine, the multipart rotor shaft comprising:

a first shaft journal with a first end flange and with an axial passage bore;

a second shaft journal with a second end flange;

a hollow carrier for a laminated rotor core, wherein the carrier for the laminated rotor core is arranged between the first shaft journal and the second shaft journal and wherein the carrier, the first end flange and the second end flange delimit a cavity between them;

a line element for conducting a cooling medium, wherein the line element forms a cooling channel inside the cavity, and wherein the cooling channel is connected to the first axial passage bore, extends between the first shaft journal and the second shaft journal, and is connected to an outer part of the cavity which is formed between the carrier and the line element;

a separating element, wherein the separating element divides the outer part of the cavity into a first partial cavity on the side of the first shaft journal, and a second partial cavity on the side of the second shaft journal; and

an internal pump driven by the rotor shaft and arranged inside the rotor shaft, to convey a cooling medium through the axial passage bore, the cooling channel, the first partial cavity and through the second partial cavity.

7. The multipart rotor shaft as claimed in claim 6 , wherein the internal pump comprises a double-suction pump impeller which is rotationally fixedly connected to the line element.

8. The multipart rotor shaft as claimed in claim 7 , wherein

the double-suction pump impeller comprises a first impeller and a second impeller,

the first impeller is arranged inside the first partial cavity and is configured to convey cooling medium present in the cooling channel into the first partial cavity via the at least one first bore of the line element, and

the second impeller is arranged inside the second partial cavity and is configured to convey cooling medium present in the cooling channel into the second partial cavity via the at least one second bore of the line element.

9. A rotor for an electric machine, the rotor comprising a multipart rotor shaft and a laminated rotor core which is rotationally fixedly mounted on a carrier of the multipart rotor shaft, wherein the rotor shaft comprising;

a first shaft journal with a first end flange and with an axial passage bore;

a second shaft journal with a second end flange;

wherein the carrier is a hollow carrier arranged between the first shaft journal and the second shaft journal and wherein the carrier, the first end flange and the second end flange delimit a cavity between them;

a line element for conducting a cooling medium, wherein the line element forms a cooling channel inside the cavity and connected to the first axial passage bore, extends between the first shaft journal and the second shaft journal, and is connected to an outer part of the cavity formed between the carrier and the line element; and

a separating element, wherein the separating element divides the outer part of the cavity into a first partial cavity on the side of the first shaft journal, and a second partial cavity on the side of the second shaft journal; and

an external pump which is arranged outside the rotor shaft and is configured to convey a cooling medium through the axial passage bore, the cooling channel, the first partial cavity and through the second partial cavity.

10. The rotor as claimed in claim 9 , wherein the first partial cavity is connected to the cooling channel via at least one first bore of the line element, and wherein the second partial cavity is connected to the cooling channel via at least one second bore of the line element.

11. The rotor as claimed in claim 9 , wherein the first end flange as at least one first opening for discharging cooling medium from the first partial cavity, and wherein the second end flange has at least one second opening for discharging cooling medium from the second partial cavity.

12. The rotor as claimed in claim 9 , wherein the separating element protrudes from the line element in the radial direction.

13. The rotor as claimed in claim 9 , wherein the separating element is integrally connected to the line element.

14. A rotor for an electric machine, the rotor comprising a multipart rotor shaft and a laminated rotor core which is rotationally fixedly mounted on a carrier of the multipart rotor shaft, wherein the rotor shaft comprising;

a first shaft journal with a first end flange and with an axial passage bore;

a second shaft journal with a second end flange;

wherein the carrier is a hollow carrier arranged between the first shaft journal and the second shaft journal and wherein the carrier, the first end flange and the second end flange delimit a cavity between them;

a line element for conducting a cooling medium, wherein the line element forms a cooling channel inside the cavity and connected to the first axial passage bore, extends between the first shaft journal and the second shaft journal, and is connected to an outer part of the cavity formed between the carrier and the line element;

a separating element, wherein the separating element divides the outer part of the cavity into a first partial cavity on the side of the first shaft journal, and a second partial cavity on the side of the second shaft journal; and

an internal pump which is arranged inside the rotor shaft and is driven by the rotor shaft, and is configured to convey a cooling medium through the axial passage bore, the cooling channel, the first partial cavity and through the second partial cavity.

15. The rotor as claimed in claim 14 , wherein the internal pump comprises a double-suction pump impeller which is rotationally fixedly connected to the line element.

16. The rotor as claimed in claim 15 , wherein the double-suction pump impeller comprises a first impeller and a second impeller,

the first impeller is arranged inside the first partial cavity and is configured to convey cooling medium present in the cooling channel into the first partial cavity via the at least one first bore of the line element, and

the second impeller is arranged inside the second partial cavity and is configured to convey cooling medium present in the cooling channel into the second partial cavity via the at least one second bore of the line element.