Rotor having supporting corset-like fibre surface structures

Abstract

The invention relates to a rotor (1) for a separately excited salient-pole electrical machine, having: - a rotor core (2) having a rotor yoke (3) and a plurality of salient poles (4) that project radially from the rotor yoke (3) and each have a rotor tooth (5) and a pole shoe (6), - rotor windings (8) for exciting a rotor magnetic field with winding conductors (9) that are wound in a plurality of layers around the rotor teeth (5) of the salient poles (4) and form winding heads (11) on axially opposing end faces of the rotor core (2), - at least one fibre for fixing and supporting the rotor windings (8), wherein the at least one fibre is wound around the associated rotor winding (8) so as to form a respective supporting corset-like fibre surface structure (13) for each salient pole (4), and in the process encloses an outer layer of the winding conductors (9) so as to axially and radially fix the associated rotor winding (8).

Description

[0001] Rotor with support corset-like fiber surface structures

[0002] The invention relates to a rotor for a separately excited salient-pole electric machine. The rotor comprises a rotor core with a rotor yoke and a plurality of salient poles projecting radially from the rotor yoke, each having a rotor tooth and a pole shoe. Furthermore, the rotor comprises rotor windings for exciting a rotor magnetic field with winding conductors wound in multiple layers around the rotor teeth of the salient poles and forming winding heads on axially opposite end faces of the rotor core, and at least one fiber for securing and supporting the rotor windings. The invention also relates to a separately excited salient-pole electric machine and a motor vehicle.

[0003] In this case, the focus is on electrical machines that can be used, for example, as drive motors for electrified motor vehicles, i.e., electric or hybrid vehicles. Such electrical machines typically have a stationary stator with energizable stator windings and a rotor mounted so as to be rotatable relative to the stator. In the case of a separately excited machine, the rotor also has energizable rotor windings. The rotor windings have winding conductors, for example wires, which, in the case of a salient-pole rotor, can be wound around salient poles or rotor poles of a rotor core and form winding overhangs on axially opposite end faces of the rotor core. At high speeds, the wires can shift due to centrifugal forces, which can lead to imbalance and rotor failure.Therefore, the winding conductors are usually fixed and stabilized, for example, by applying a potting resin or a resin-based resin into the spaces between the winding conductors and allowing it to cure there. The disadvantage is that a rotor encapsulated with resin or potting compound is heavy, expensive due to additional process steps, components, and labor, and is also difficult to recycle.

[0004] Also known from the prior art, for example from DE 10 2021 124234 A1, is a rotor which has a tensioning and deflecting device and a roving winding with a roving, through which several windings are formed, offset in the circumferential direction and spanning the rotor windings of each salient pole pair. By means of the tensioning and deflecting device, roving sections are guided over the winding heads to form a winding between radially opposite salient poles and are deflected along the circumferential direction while being guided over the winding heads to form a winding transition between two windings. Such a roving winding eliminates the need for encapsulation of the rotor, but the production of the roving winding and thus the manufacture of the rotor are highly complex.

[0005] It is an object of the present invention to provide a fiber winding for a rotor of an electrical machine which can be produced simply and cost-effectively and has a particularly high support effect.

[0006] This object is achieved according to the invention by a rotor, a salient-pole machine, a motor vehicle, and an arrangement having the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0007] A rotor according to the invention for a separately excited electric salient-pole machine has a rotor core with a rotor yoke and a plurality of salient poles projecting radially from the rotor yoke, each of which has a rotor tooth and a pole shoe. Furthermore, the rotor has rotor windings for exciting a rotor magnetic field with winding conductors wound in several layers around the rotor teeth of the salient poles and forming winding heads on axially opposite end faces of the rotor core. Furthermore, the rotor has at least one fiber for securing and supporting the rotor windings. The at least one fiber is wound around the rotor windings to form a support corset-like fiber surface structure for each salient pole and encloses an outer layer of the winding conductors for axial and radial securing of the rotor windings.

[0008] A separately excited electric salient-pole machine according to the invention for a motor vehicle comprises a stator and a rotor according to the invention that is rotatably mounted relative to the stator. Furthermore, the invention relates to a motor vehicle with at least one salient-pole machine according to the invention. The motor vehicle is designed, in particular, as an electrified motor vehicle and has the at least one salient-pole machine as a drive motor. The salient-pole machine is designed, in particular, as a current-excited internal-rotor synchronous machine (SSM).

[0009] The rotor core of the salient-pole rotor is designed, for example, as a laminated core made of axially stacked and interconnected electrical steel laminations. The rotor core has the rotor yoke, for example an annular one, through which a rotor shaft can be passed and connected in a rotationally fixed manner to the rotor core. The salient poles project radially from the rotor yoke, each having a rotor tooth, in particular one with parallel flanks, and a pole piece, in particular one shaped like a segment of a circle. The rotor teeth project radially from the rotor yoke and are arranged at a distance from one another in the circumferential direction. Partial regions of the pole pieces project beyond the rotor teeth along the circumferential direction, so that the winding conductors of the rotor windings, which are wound around the rotor teeth, are arranged radially between the pole pieces and the rotor yoke and are held on the rotor teeth by the pole pieces when the salient-pole rotor rotates.The axial winding sections of the rotor windings are arranged in axial slots formed between the tooth flanks of two adjacent rotor teeth, and the end-face winding sections of the rotor windings extend over the end faces of the rotor teeth. The tooth flanks and end faces of a rotor tooth form its outer sides.

[0010] In order to fix and stabilize the winding conductors, which are preferably designed as wires and wound around the rotor teeth in several layers and several turns per layer, a fiber surface structure is provided for each salient pole, which encloses the respective rotor winding like a support corset. The fiber surface structures are applied in particular to the outer layer or the last upper winding of the respective rotor winding and cover it in particular completely. The fiber surface structure is arranged overlapping with the outer sides of the respective rotor tooth. The fiber surface structure has two axial structural sections for each salient pole, which are arranged parallel to the tooth flanks in the slots of the associated salient pole and cover the axial winding sections, and two end-face structural sections, which are arranged parallel to the end faces of the rotor teeth and cover the end-face winding sections.These fiber surface structures, in particular, replace the need for potting the rotor, so that the rotor windings are unpotted, and thus no potting compound is arranged between the winding conductors. The rotor is thus designed without potting compound. The fiber surface structures are significantly lighter than potting compound and are easier to manufacture. Furthermore, unlike potting compound, the fiber surface structures can be easily removed for rotor recycling.

[0011] The fiber surface structures comprise at least one high-tensile fiber, for example a carbon fiber, a glass fiber, an amide or a sisal fiber. In particular, several fibers are bundled into a roving, for example a ribbon-like roving, which is wound into the fiber surface structure. The fiber surface structures can be designed as fiber layups or as fiber braids and can have one or more layers. In a fiber layup, the fibers are laid in one or more layers on the upper layer of the rotor winding, whereby the fibers within a layer can run parallel to one another, for example, and the fibers of two layers can have different orientations. In a fiber braid or fiber knit, the fibers are woven or braided within a layer.

[0012] A curable impregnating resin can be used to stabilize the fiber surface structure. For this purpose, the at least one fiber is pre-impregnated with the impregnating resin, forming a prepreg, or is impregnated or laminated with the impregnating resin in a separate process step prior to the production of the fiber surface structure. This impregnating resin can then be thermally activated after the salient poles have been wound, causing it to liquefy, spread within the fiber surface structure, and harden there.

[0013] It can be provided that a separate, closed fiber surface structure is formed for each salient pole. Each salient pole is thus wound separately by winding the fiber around the rotor winding and fixing one fiber end, for example, by gluing it, to the associated fiber surface structure. The fiber surface structures of different salient poles are therefore not connected to one another. Alternatively, the fiber surface structures can be wound with a continuous fiber, so that the fiber surface structures are connected via at least one fiber section, for example, one that runs partially across the end face of the rotor core. The fiber surface structures can be wound successively. This means that as soon as one fiber surface structure is completely wound, the fiber can be guided to another salient pole, which is then wound.Alternatively, multiple fiber surface structures can be wound in parallel by at least partially winding another fiber surface structure with the same fiber before completing a fiber surface structure. Thus, during the winding of the continuous continuous fiber, the fibers can also be switched back and forth between the salient poles to increase the stability of the fiber surface structures. Once the last salient pole is wound, the fiber end is attached to the corresponding fiber surface structure.

[0014] The embodiments presented with reference to the rotor according to the invention and their advantages apply accordingly to the salient pole machine according to the invention and to the motor vehicle according to the invention.

[0015] Further features of the invention emerge from the claims, the figure, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figure, can be used not only in the respective specified combination, but also in other combinations or on their own.

[0016] The invention will now be explained in more detail using a preferred embodiment and with reference to the drawings. They show:

[0017] Fig. 1 is a schematic perspective view of a rotor design; and

[0018] Fig. 2 is a schematic cross-sectional view of the rotor.

[0019] In the figures, identical and functionally identical elements are provided with the same reference numerals.

[0020] Fig. 1 and Fig. 2 show different perspectives of a rotor 1 for an electrical machine. The rotor 1 is manufactured in a salient-pole design and has a rotor core 2 with a rotor yoke 3 and salient poles 4. The salient poles 4 each have a rotor tooth 5 and a pole shoe 6. The rotor yoke 3 encloses a rotor shaft 7, which is rotationally fixedly connected to the rotor core 2. The rotor 2 also has energizable rotor windings 8 for exciting a rotor magnetic field. The rotor windings 8 have winding conductors 9, which are designed as wires and are wound around the rotor teeth 5. Star disks 10 can also be arranged on axially opposite end faces of the rotor core 2, which serve to guide the winding conductors 9 over the end faces of the rotor core 2. The geometric shape of the star disks 8 corresponds to the salient-pole design of the rotor core 2.The sections of the winding conductors 9 extending over the end faces form winding heads 11. These can be held on the star disks 10 by axially projecting projections 12 of the star disks 10 during rotation of the rotor 1 and thus supported against the centrifugal forces acting during rotation.

[0021] To improve the supporting effect of the star disks 10 against centrifugal forces and to fix the winding conductors 9, the rotor 1 also has a fiber surface structure 13 for each salient pole 4, for example a fiber scrim or a fiber knit, although only one fiber surface structure 13 is shown here. The fiber surface structure 13 encloses or surrounds the associated rotor winding 8. The fiber surface structure 13 covers the uppermost layer of the rotor winding 8 and encloses the winding heads 11 and the axial winding sections 14 of the rotor windings 8. The fiber surface structure 13 thus forms a support corset for the associated rotor winding 8. The fiber surface structure 13 can be formed by at least one fiber, in that the at least one fiber is wound around the salient pole 4 equipped with the winding conductor 8, parallel to the outer surfaces of the rotor tooth 5. The at least one fiber can, for example, comprise a carbon fiber reinforced plastic.

Claims

Patent claims 1. Rotor (1) for a separately excited electric salient pole machine comprising: - a rotor core (2) with a rotor yoke (3) and a plurality of salient poles (4) projecting radially from the rotor yoke (3), each having a rotor tooth (5) and a pole shoe (6), - rotor windings (8) for exciting a rotor magnetic field with winding conductors (9) which are wound in several layers around the rotor teeth (5) of the salient poles (4) and form winding heads (11) on axially opposite end faces of the rotor core (2), - at least one fiber for fixing and supporting the rotor windings (8), characterized in that the at least one fiber is wound around the associated rotor winding (8) to form a supporting corset-like fiber surface structure (13) per salient pole (4) and thereby encloses an outer layer of the winding conductors (9) for the axial and radial fixing of the associated rotor winding (8).

2. Rotor (1) according to claim 1, characterized in that the winding conductors (9) are designed as wires.

3. Rotor (1) according to claim 1 or 2, characterized in that the rotor windings (8) are uncast.

4. Rotor (1) according to one of the preceding claims, characterized in that the fiber surface structures (13) are formed by a plurality of fibers forming rovings.

5. Rotor (1) according to one of the preceding claims, characterized in that the at least one fiber is a carbon fiber, a glass fiber, an aramid fiber or a sisal fiber.

6. Rotor (1) according to one of the preceding claims, characterized in that a separate, closed fiber surface structure (13) is formed for each salient pole (4).

7. Rotor (1) according to one of claims 1 to 5, characterized in that the fiber surface structures (13) are wound with a continuous fiber, so that the fiber surface structures (13) are connected via at least one fiber section.

8. Rotor (1) according to one of the preceding claims, characterized in that the respective fiber surface structure (13) completely covers the associated rotor winding (8).

9. Separately excited electric salient pole machine for a motor vehicle comprising a stator and a rotor (1) rotatably mounted with respect to the stator according to one of the preceding claims.

10. Motor vehicle with at least one salient pole machine according to claim 9.

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