Protective sleeve for a rotor

Abstract

Protective sleeve (12, 120, 130, 140, 160) for a rotor (1) of an electric machine, in particular for an air supply device for supplying air to a fuel cell stack, having 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) is oriented towards the second shaft body (11), wherein the protective sleeve (12) is configured to support the magnetic body (13) orto protect it from environmental influences, the protective sleeve (12) being designed for this purpose to surround the magnetic body (13) in the axial direction, characterized in that the protective sleeve is constructed from at least two interconnected segments (123, 125; 133, 135; 143, 145, 147, 149, 151, 153; 163).

Description

State of the art

[0001] The invention is based on a protective sleeve according to the class of the independent claim.

[0002] For example, in mobile fuel cell applications, air compressors are required to supply air to the cathode side of the fuel cells, as described in DE 20 2021 103 279 U1. Extremely fast-rotating electric motors are used. The rotor of such electric motors consists of a shaft with integrated magnets. These must be fixed to the shaft. Due to the high centrifugal forces, a sleeve is placed over the magnets to hold and protect them. Disclosure of the invention

[0003] In contrast, the protective sleeve according to the invention has the advantage of avoiding both the correspondingly high material waste costs and the equally high additional processing costs by being constructed from segments, rather than being manufactured from a bar material.

[0004] The measures listed in the dependent claims enable advantageous further developments and improvements of the protective sleeve specified in the independent claim. Short description of the drawings

[0005] Embodiments of the invention are illustrated in the drawing and explained in more detail in the following description.

[0006] It shows Fig. 1 a section of a rotor, Fig. 2 a radial cross-section of a protective sleeve, Fig. 3 a radial cross-section of another protective sleeve, Fig. 4 a radial cross-section of another protective sleeve and Fig. 5 a perspective view of another protective sleeve. Embodiments of the invention

[0007] Fig. 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 is aligned with the second shaft body 11.

[0008] Each of the end faces 21, 22 partially rests directly on the adjacent shaft body 10, 11.

[0009] The magnetic body 13 is surrounded by a sleeve 12 for support and protection against environmental influences. The sleeve 12 also represents the mechanical connection between the two shaft ends and contributes significantly to the stability and strength of the shaft.

[0010] When the electric machine is designed 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 of the fuel cell stack is arranged to the left and right of the magnetic body on the shaft bodies in a manner not shown in detail.

[0011] The shaft bodies 10, 11 are preferably made of a metallic material. The sleeve 12 is made of a non-magnetic, preferably metallic, material.

[0012] 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 respectively 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, wherein a cylindrical end face 30 or 31 of the respective projection can rest directly on the magnetic body 13 or, alternatively, a disc-shaped support element (not shown in detail) made of non-magnetic, preferably metallic material can be arranged between the magnetic body 13 and the shaft bodies 10 or 11.

[0013] 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 Fig. 1 shown section of the rotor 1 has a continuous cylinder surface.

[0014] Such a rotor can be produced in a manufacturing process in which the two shaft bodies 10, 11 and the magnetic body 13 are joined thermally or non-thermally in a common process step or in separate process steps, for example, by material bonding. The joining preferably takes place with the support or protective sleeve 12 included.

[0015] This ensures that the magnetic body is protected against the extremely high centrifugal forces generated by the rotational speeds by means of a pressed-on or shrunk-on metallic, but non-magnetic sleeve. The magnetic body, pressed or shrunk into the protective sleeve, and the shaft bodies are connected by a welded joint.

[0016] Fig. 2 shows a radial cross-section of a protective sleeve 120. This is constructed from two segments designed as half-shells 123 and 125, wherein the half-shells extend along the Fig. 1, extend from one end of the protective sleeve to the other end of the protective sleeve, i.e. from the shaft body 10 to the shaft body 11. The two half-shells are, for example, materially connected, in particular welded or soldered to one another.

[0017] The segments can be manufactured before they are connected, for example, by bending sheet metal.

[0018] Alternatively, the protective sleeve can also consist of more than two circular segments, which together form the hollow cylinder forming the protective sleeve.

[0019] Fig. Figure 3 shows a radial cross-section of a protective sleeve 130, in which this cross-section is angular, in the example shown, square. It is composed of two segments 133 and 135, resulting in a square cross-section. The two segments preferably have an identical radial cross-section. Alternatively, the square cross-section can also be constructed from four segments, thus eliminating the need to bend the segments.

[0020] Fig. Figure 4 shows a radial cross-section of a protective sleeve 140, in which this cross-section is angular, hexagonal in the example shown. It is composed of several segments 143, 145, 147, 149, 151, and 153, resulting in a hexagonal cross-section. Each of these segments is an elongated strip with a suitable edge shape, allowing the strips to be joined together to form a tube with a hexagonal cross-section.

[0021] The number of segments is variable, but >2, even an odd number of segments is possible.

[0022] The segments of the square versions according to Fig. 3 or Fig. 4 can, for example, be joined in a material-to-material manner, in particular by welding or soldering.

[0023] In cross-section, square designs according to Fig. 3 or Fig. 4 can be approximated to a rotationally symmetrical geometry through machining, if necessary. However, the polygonal shape offers the advantage that the magnetic body is not supported around its entire circumference. This allows the segment sleeve to deform elastically and better compensate for the different thermal expansions of the two materials.

[0024] Fig. Figure 5 shows a protective sleeve 160 consisting of several segments 163, which are arranged or stacked one behind the other in the axial direction 2. In this case, the segments are designed as rings. The rings can be manufactured, for example, by laser or waterjet cutting from a sheet metal having a thickness of, for example, 3 millimeters. QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 20 2021 103 279 U1

[0002]

Claims

[1] Protective sleeve (12, 120, 130 140, 160) for - a rotor (1) for an electrical machine, in particular for a gas supply device for supplying air to a fuel cell stack, comprising 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 aligned with the first shaft body (10) and the second end face (22) is aligned with the second shaft body (11), - wherein the protective sleeve (12) is designed to support the magnetic body (13) or to protect it from environmental influences, - wherein the protective sleeve (12) is arranged for this purpose to surround the magnetic body (13) in the axial direction, characterized by that the protective sleeve is constructed from at least two interconnected segments (123, 125; 133, 135; 143, 145, 147, 149, 151, 153; 163). [2] Protective sleeve according to claim 1, characterized by that the segments join together in a radial cross-section of the protective sleeve to form a circular tube shape. [3] Protective sleeve according to claim 1, characterized by that the segments join together in a radial cross-section of the protective sleeve to form a square tube shape. [4] Protective sleeve according to claim 3, characterized by that the tube shape is square. [5] Protective sleeve according to claim 3, characterized by that the tube shape is polygonal, for example pentagonal, preferably hexagonal. [6] Protective sleeve according to one of claims 1 to 5, characterized bythat each segment extends in the axial direction (2) from one end of the protective sleeve to the other end of the protective sleeve. [7] Protective sleeve according to claim 1, characterized by that the segments are arranged along the axial direction (2). [8] Protective sleeve according to one of the preceding claims, characterized by that the segments are firmly connected to each other. [9] Protective sleeve according to claim 8, characterized by that the segments are welded together. [10] Protective sleeve according to one of the preceding claims, characterized by that the segments are made of a non-magnetic material. [11] Protective sleeve according to one of the preceding claims, characterized by that the segments are made of a metallic material. [12] Method for producing a protective sleeve according to one of the preceding claims, characterized bythat at least two segments (123, 125; 133, 135; 143, 145, 147, 149, 151, 153; 163) are provided and that the at least two segments are connected to one another. [13] 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), with a protective sleeve (12, 120, 130, 140, 160) according to one of claims 1 to 11 surrounding the magnetic body (13). [14] A method for producing a rotor according to claim 13, characterized bythat the protective sleeve is manufactured according to claim 12.

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