Rotor for an electric machine

Abstract

The invention relates to a rotor (1) for an electric machine, in particular for a gas supply device for supplying air to a fuel cell stack, comprising at least one magnetic body (13) which is arranged in an axial direction (2) between a first (10) and a second shaft body (11) of the rotor, wherein the first shaft body (10), the magnetic body (13) and the second shaft body (11) are arranged one behind the other in the axial direction of the rotor, wherein the at least one magnetic body (13) has end faces (21, 22) arranged one behind the other in the axial direction (2), wherein the first end face (21) is oriented to the first shaft body (10) and the second end face (22) is oriented to the second shaft body (11), characterised in that each of the end faces (21, 22) rests at least partially directly on the respective adjacent shaft body (10, 11).

Description

[0001] Description

[0002] title

[0003] Rotor for an electric machine

[0004] State of the art

[0005] The invention is based on a rotor according to the preamble of the independent claim. Such a rotor is already known from DE 10 2021 207399 A1, but it is composed of a large number of parts.

[0006] Disclosure of the invention

[0007] The rotor according to the invention with the characterizing features of the independent claim has the advantage of an optimized design, so that it can be used, for example, in an air compressor for fuel cell applications where reliable operation at high speeds is important, whereby the design can be carried out cost-effectively and using as few components as possible. In particular, by directly arranging shaft bodies with a magnetic body in series, i.e. without arranging further components between the shaft bodies and the magnetic body, a compact design consisting of few components is ensured. Furthermore, this can at least partially support the end faces of the magnetic body by resting end faces of the shaft bodies in order to prevent displacement of the magnetic body.

[0008] The measures listed in the dependent claims enable advantageous further developments and improvements of the rotor specified in the independent claim.

[0009] It is particularly advantageous to encapsulate the magnetic body, which can be achieved by providing a support sleeve in addition to the shaft bodies resting on the ends in order to support the magnetic body or to protect it from environmental influences.

[0010] Advantageously, a metallic material can be used to manufacture the shaft bodies.

[0011] In a further advantageous manner, a metallic, non-magnetic material can be used to manufacture the support sleeve.

[0012] Advantageously, the rotor according to the invention can be manufactured using a cost-effective process in which the two shaft bodies and the magnetic body are thermally joined, preferably including the support or protective sleeve laterally surrounding the magnetic body. This also makes it easy to prevent the formation of edges along the rotor surface during joining. Furthermore, a direct series of shaft bodies with a magnetic body can be achieved using few components, for example, without providing additional axial, i.e., terminal, covers for the magnetic body. Brief Description of the Drawings

[0013] Embodiments of the invention are illustrated in the drawing and explained in more detail in the following description

[0014] The only figure 1 shows a section of a rotor.

[0015] Embodiments of the invention

[0016] Figure 1 shows a substantially central section of a rotor 1 for an electrical machine, in particular for a gas supply device or an electric air compressor for supplying air to a fuel cell stack, with a magnetic body 13 which is arranged in an axial direction 2 between a first (10) and a second shaft body 11 of the rotor. The first shaft body 10, the magnetic body 13 and the second shaft body 11 are arranged one behind the other in the axial direction of the rotor, wherein the at least one magnetic body 13 has end faces 21, 22 arranged one behind the other in the axial direction 2. The first end face 21 is aligned with the first shaft body 10 and the second end face 22 with the second shaft body 11.

[0017] Each of the end faces 21, 22 lies partially directly on the adjacent shaft body 10, 11.

[0018] The magnetic body 13 is surrounded by a sleeve 12 for support and protection against environmental influences.

[0019] When the electric machine is configured as an electric air compressor for fuel cell applications, a compressor impeller for the air to be compressed and / or a turbine wheel for energy recovery from flowing exhaust gas from the fuel cell stack are arranged on the shaft bodies to the left and right of the magnetic body in a manner not shown in detail. The shaft bodies 10, 11 are preferably made of a metallic material. The sleeve 12 is made of a non-magnetic, preferably metallic material.

[0020] In detail, the shaft bodies 10, 11 each have, on their side facing the magnetic body 13, a region 24 or 25 with a stepped geometry such that the end faces 21, 22 of the magnetic body only partially rest on the adjacent shaft body 10 or 11. The stepped geometries are rotationally symmetrical to the axial direction 2 and each have a cylindrical wall-shaped projection 27 or 28, with a cylindrical end face 30 or 31 of the respective projection resting directly on the magnetic body 13.

[0021] Furthermore, the stepped geometries 24, 25 each comprise an outer circumferential step 33 or 34 such that the sleeve 12 can rest flush on the shaft bodies at its ends facing the shaft bodies 10, 11, so that the section of the rotor 1 shown in Figure 1 has a continuous cylindrical surface.

[0022] Such a rotor can be produced in a manufacturing process in which the two shaft bodies 10, 11 and the magnetic body 13 are thermally joined in a single process step or in separate process steps, for example, by a material bond. The joining preferably takes place with the support or protective sleeve 12 included.

Claims

Claims 1. Rotor (1) for an electrical machine, in particular for a gas supply device for supplying air to a fuel cell stack, with at least one magnetic body (13) which is arranged in an axial direction (2) between a first (10) and a second shaft body (11) of the rotor, wherein the first shaft body (10), the magnetic body (13) and the second shaft body (11) are arranged one behind the other in the axial direction of the rotor, wherein the at least one magnetic body (13) has end faces (21, 22) arranged one behind the other in the axial direction (2), wherein the first end face (21) is aligned with the first shaft body (10) and the second end face (22) is aligned with the second shaft body (11), characterized in that each of the end faces (21, 22) rests at least partially directly on the respectively adjacent shaft body (10, 11).

2. Rotor according to claim 1, characterized in that the shaft bodies (10, 11) are made of a metallic material.

3. Rotor according to claim 1 or 2, characterized in that the magnetic body (13) is surrounded by a sleeve (12) for support or protection against environmental influences.

4. Rotor according to claim 3, characterized in that the sleeve (12) is made of a non-magnetic material.

5. Rotor according to claim 4, characterized in that the sleeve (12) is made of a metallic material.

6. Rotor according to one of the preceding claims, characterized in that the shaft bodies (10, 11) each have, on their side facing the magnetic body (13), a region (24, 25) with a stepped geometry such that the end faces (21, 22) only partially rest on the respectively adjacent shaft body (10, 11).

7. Rotor according to claim 6, characterized in that the respective stepped geometry is rotationally symmetrical to the axial direction (2).

8. Rotor according to claim 7, characterized in that the stepped geometry forms a cylindrical wall-shaped projection (27, 28) of the respective shaft body (10, 11), wherein a cylindrical end face (30, 31) of the respective projection rests directly on the magnetic body (13).

9. Rotor according to claim 3 and one of claims 6, 7 or 8, characterized in that the stepped geometry (24, 25) each comprises an outer circumferential step (33, 34) such that the sleeve (12) rests flush on the shaft bodies at its ends facing the shaft bodies (10, 11).

10. A method for producing a rotor (1) according to one of the preceding claims, characterized in that the two shaft bodies (10, 11) and the magnetic body (13) are thermally joined.

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