Rotor for an electric machine

Abstract

Rotor (1, 100) for an electric 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 oriented towards the first shaft body (10) and the second end face (22) towards the second shaft body (11), with a sleeve (12) surrounding the magnetic body (13) for support orfor the protection of the magnetic body, characterized in that the sleeve (12) is connected to at least one of the two wave bodies (10, 11) via a reversibly detachable connection (60, 63).

Description

State of the art

[0001] The invention relates to a rotor according to the preamble of the independent claim.

[0002] Rotor assemblies are known from the state of the art, for example from WO 2021 / 063604 A1.

[0003] A bandage for such a rotor is already known from DE 10 2021 207 399 A1.

[0004] It is known from WO 2006 / 043734 A1 to use the material Inconel in the manufacture of a rotor of an air compressor. Disclosure of the invention

[0005] The rotor according to the invention advantageously ensures flexible and cost-effective handling during assembly and / or repair.

[0006] In particular, the rotor is advantageously suited for a high-speed air compressor for fuel cells to supply the cathode side of the fuel cells with oxygen.

[0007] The measures listed in the dependent claims enable advantageous further developments and improvements of the protective sleeve specified in the independent claim. Brief description of the drawings

[0008] Exemplary embodiments of the invention are shown in the drawing and explained in more detail in the following description.

[0009] They show Fig. 1 a section of a rotor with a protective sleeve, Fig. 2 a section of an alternative rotor with a protective sleeve, Fig. 3 a rotor, Fig. 4 a terminal section of a rotor and Fig. 5 another rotor. Embodiments of the invention

[0010] Fig. Figure 1 shows a substantially central section of a rotor 1 for an electric 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 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 oriented towards the first shaft body 10, and the second end face 22 is oriented towards the second shaft body 11.

[0011] Each of the end faces 21, 22 lies partially directly on the respective adjacent wave body 10, 11.

[0012] The magnetic body 13 is surrounded by a sleeve 12 for support and protection against environmental influences.

[0013] In the configuration of the electric machine 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 the flowing exhaust gas of 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. Electric machines with a rotor according to the invention can also be equipped without a compressor impeller or turbine wheel, depending on the intended application.

[0014] The shaft bodies 10, 11 are preferably made of a metallic material. The sleeve 12 is made of a non-magnetic, preferably metallic, material.

[0015] Preferably, the wave bodies 10, 11 each have a region 24 or 25 with a stepped geometry on their side facing the magnetic body 13, such that the end faces 21, 22 of the magnetic body only partially rest on the respective adjacent wave body 10 or 11. The stepped geometries are rotationally symmetrical with respect to the axial direction 2 and each has a cylindrical wall-shaped projection 27 or 28, wherein a cylindrical end face 30 or 31 of the respective projection rests directly on the magnetic body 13.

[0016] Furthermore, the stepped geometries 24, 25 each comprise an outer circumferential step 33 or 34 such that the sleeve 12 can lie flush on the shaft bodies at its ends facing the shaft bodies 10, 11, so that the in Fig. Figure 1 shows a section of rotor 1 that has a continuous cylindrical surface.

[0017] 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 common process step or in separate process steps, for example by metallurgical bonding. The joining preferably takes place including the support or protective sleeve 12.

[0018] Fig. Figure 2 shows a substantially central section of an alternative rotor 100 for an electric machine, in which the same or similar components as in Fig. 1 are designated with the same reference numeral and are not described again. In contrast to rotor 1, in the alternative rotor 100 a preferably non-magnetic metallic cover disk 40 is located between the shaft bodies 10, 11 and the magnetic body 13, so that the end faces 21, 22 of the magnetic body rest on the respective cover disk, while the cover disks in turn rest on the cylindrical end faces 30, 31 on the side facing away from the magnetic body.

[0019] In the orders according to Fig. 1 and Fig. 2. The material for the protective sleeve is non-magnetic or a nitrogen-alloyed, austenitic steel (high-nitrogen stainless steel), in particular one with very low magnetic permeability. For example, the magnetic permeability is less than 1.005.

[0020] In the orders according to Fig. 1 and Fig. 2. The magnetic body can be solid or alternatively provided with a preferably centrally arranged cavity.

[0021] Fig. Figure 3 shows a rotor 1 after Fig. 2 in its entire axial extent, whereby for the sake of simplicity, the connection of a compressor impeller and / or turbine wheel is omitted in the figurative representation, if applicable depending on the application.

[0022] Alternatively, the cover plates 40 can be omitted for structural reasons, then the total axial extent of a rotor is determined by Fig. 1.

[0023] The shaft body 11 has an axial bearing disc 50 on its side facing away from the magnetic body 13, which is integrally integrated into the shaft body 11. Alternatively, the axial bearing disc can also be omitted.

[0024] The sleeve 12 is connected to at least one of the two, preferably both, shaft bodies via a reversibly detachable connection 60. In the present case, the reversibly detachable connection is formed by a press fit and / or an adhesive bond, which can be produced, for example, in a thermal joining process.

[0025] An adhesive bond can also be created in such a way that the components are joined together in several process steps in a manner that is difficult or impossible to remove. Preferably, however, an adhesive bond is created in such a way that a reversibly removable connection is formed, even if it is difficult to remove.

[0026] Fig. Figure 4 shows a terminal region of a rotor in the area of ​​the shaft body 11, in which, alternatively to the arrangement according to Fig. 3. No axial bearing disc integrally connected to the shaft body 11 is provided. The axial bearing area is designed as a separate component. An axial bearing disc 51 is shown as an example. This axial bearing disc 51 is connected to the shaft body 11 via a force-fit, friction-fit, and / or material-fit connection 53.

[0027] Fig. Figure 5 shows an alternative rotor design in its entire axial extent, similar to Fig. 3, however, in contrast to the arrangement according Fig. 3 the reversibly detachable connection is designed as a screw connection 63.

[0028] To create the screw connection, in one embodiment mirror surfaces 65 can be provided on the outer circumference of the respective shaft body and the sleeve in the area of ​​the connection 63. The mirror surfaces serve to form a tool engagement surface in order to apply the torques required to create the screw connection between each shaft body and one end of the sleeve. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2021 / 063604 A1

[0002] DE 10 2021 207 399 A1

[0003] WO 2006 / 043734 A1

[0004]

Claims

[1] Rotor (1, 100) for an electric machine, in particular for a gas supply device for supplying air to a fuel cell stack, with at least one magnetic body (13) 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 towards the first shaft body (10) and the second end face (22) towards the second shaft body (11), with a sleeve (12) surrounding the magnetic body (13) for supporting or protecting the magnetic body, characterized by, that the sleeve (12) is connected to at least one of the two shaft bodies (10, 11) via a reversibly detachable connection (60, 63). [2] Rotor according to claim 1, characterized by , that the sleeve (12) is connected to both shaft bodies via a reversibly detachable connection (60, 63). [3] Rotor according to one of claims 1 or 2, characterized by , that the reversibly detachable connection (60) is a compression bandage and / or an adhesive bandage. [4] Rotor according to one of claims 1 or 2, characterized by , that the reversibly detachable connection (63) is a screw connection. [5] Rotor according to claim 4, characterized by , that in the area of ​​the screw connection mirror surfaces (65) are arranged on the shaft bodies and the sleeve (12). [6] Rotor according to any one of the preceding claims, characterized by , that at least one of the two shaft bodies (10, 11) has an axial bearing area (50, 51). [7] Rotor according to claim 5, characterized bythat the axial bearing area is an axial bearing disc. [8] Rotor according to claim 7, characterized by , that the axial bearing disc (50) is formed integrally with the at least one shaft body (10, 11). [9] Rotor according to claim 7, characterized by , that the axial bearing disk (51) is connected to the at least one shaft body (10, 11) by friction and / or material bonding. [10] Rotor according to any one of the preceding claims, characterized by , that the sleeve (12) is made of a non-magnetic material. [11] Rotor according to any one of claims 1 to 9, characterized by , that the sleeve (12) is made of a nitrogen-alloyed, austenitic steel. [12] Rotor according to claim 11, characterized by that nitrogen-alloyed austenitic steel has a very low magnetic permeability. [13] Method for manufacturing a rotor according to any one of the preceding claims, characterized by, that the sleeve (12) is reversibly detachably connected (60, 63) to at least one of the two shaft bodies (10, 11).

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