Electric rotating machine and geared motor unit

Abstract

The invention relates to an electric rotating machine (1) comprising a rotor shaft (3) and a rotor (4) secured to the rotor shaft (3), wherein the rotor shaft (3) is formed by a first rotor shaft portion (5) and a separate second rotor shaft portion (6), and the first rotor shaft portion (5) and the second rotor shaft portion (6) are force-transmittingly connected via an electrically insulated connection (7). The invention additionally relates to a geared motor unit (2) comprising the electric rotating machine (1) and a gear unit (15).

Description

[0001] Electric rotary machine and geared motor unit

[0002] The invention relates to an electric rotary machine, in particular a radial flux machine, with a rotor shaft and a rotor mounted on / arranged on the rotor shaft. The invention also relates to a geared motor unit comprising the electric rotary machine and a gearbox.

[0003] Rotary machines, in particular radial flux machines, are already known from the prior art. For example, WO 2021 / 244695 A1 discloses such a rotary machine.

[0004] However, the current state of the art has the disadvantage that (parasitic) currents cannot be dissipated via the stator, or only insufficiently. This results in currents being induced in conductive components, which can lead to damage of individual components. For example, this can cause pitting, graying, and / or current breakdowns, which should be avoided.

[0005] The object of the invention is therefore to avoid or at least mitigate the disadvantages of the prior art. In particular, a rotary machine is to be provided in which damaging, parasitic currents through components that could be damaged by them are reduced or avoided.

[0006] This problem is solved by an electric rotary machine with the features of claim 1 and by a geared motor unit with the features of the dependent claim. Advantageous embodiments are the subject of the dependent claims.

[0007] The invention relates to an electric rotary machine, in particular a radial flux machine, with a rotor shaft and a rotor mounted on the rotor shaft, wherein the rotor shaft is formed by a first rotor shaft section and a separate second rotor shaft section, the first rotor shaft section and the second rotor shaft section being connected via an electrically insulated connection for force transmission, in particular torque transmission. This means that the rotor shaft is formed in multiple parts and its parts are connected to each other via the electrically insulated connection / coupling. The (two) rotor shaft sections are connected to each other for torque transmission and are electrically insulated from each other.

[0008] According to a preferred embodiment, the first rotor shaft section and the second rotor shaft section can be formed via a first coupling element formed on the first rotor shaft section and a second coupling element formed on the second rotor shaft section. The first coupling element can, in particular, be integral with the first rotor shaft section. That is, the first coupling element can, in particular, be metallic (like the first rotor shaft section). The second coupling element can, in particular, be integral with the second rotor shaft section. That is, the second coupling element can, in particular, be metallic (like the second rotor shaft section).

[0009] Preferably, the first coupling part can be arranged radially outside and the second coupling part radially inside. Alternatively, the first coupling part can be arranged radially inside and the second coupling part radially outside. In other words, the first rotor shaft section and the second rotor shaft section are arranged radially nested section by section. In particular, the first rotor shaft section and the second rotor shaft section are arranged coaxially.

[0010] Within the scope of the present invention, the terms “radial” and “axial” always refer to the axis of rotation of the electric rotary machine.

[0011] According to a preferred embodiment, the first coupling part and the second coupling part can be spaced apart by a (radial) gap, i.e., by a nominal air gap. This means that, in particular, the metallic parts of the first rotor shaft section and the second rotor shaft section are not in (radial) contact with each other. This has the advantage that there is no direct electrical connection between the first rotor shaft section and the second rotor shaft section.

[0012] According to a preferred embodiment, an insulating material can be arranged in the (radial) gap between the first coupling part and the second coupling part. In particular, the (radial) gap can be (completely) filled with the insulating material. This means that the first coupling part and the second coupling part are radially separated from each other by the insulating material.

[0013] According to a preferred embodiment, the first rotor shaft section and the second rotor shaft section can be spaced apart by an (axial) gap. This means that, in particular, the metallic parts of the first rotor shaft section and the second rotor shaft section are not in (axial) contact with each other. This has the advantage that there is no direct electrical connection between the first rotor shaft section and the second rotor shaft section.

[0014] According to a preferred embodiment, an insulating material can be arranged in the (axial) gap between the first rotor shaft section and the second rotor shaft section. In particular, the (axial) gap can be (completely) filled with the insulating material. This means that the first rotor shaft section and the second rotor shaft section are axially separated from each other by the insulating material.

[0015] In other words, the first rotor shaft section and the second rotor shaft section are connected to each other via an electrically insulated layer capable of transmitting a mechanical force. According to a preferred embodiment, the insulating material can preferably be a plastic. This allows for a suitable insulating effect to be provided cost-effectively.

[0016] According to a preferred embodiment, the rotary machine can have a coupling through which the first rotor shaft section and the second rotor shaft section are connected in a torque-transmitting manner. In other words, the electrically insulated connection can be designed as a (torque-transmitting) coupling. That is, the first coupling part and the second coupling part together form the coupling.

[0017] According to a preferred embodiment, the first coupling part and the second coupling part can form a positive-locking connection. In particular, the coupling can be designed as a (plug-in) toothed connection or as a polygonal connection. For example, the plug-in toothed connection can be formed by internal and external teeth. For example, the polygonal connection can be formed by an internal polygon and an external polygon, i.e., by a (preferably regular) square, pentagonal, hexagonal, or other polygonal geometry. Other positive-locking geometries are possible. In this way, a positive-locking torque transmission can be ensured in a simple manner.

[0018] According to a preferred embodiment, the first coupling part and the second coupling part can form a friction-fit connection and / or a material-fit connection. The friction-fit and / or material-fit connection can be present in addition to the positive-fit connection.

[0019] According to an alternative preferred embodiment, the first coupling part and the second coupling part can form a purely friction-based connection and / or a purely material-based connection. The insulating material is selected such that its shear strength is suitable for transmitting torque between the first rotor shaft section and the second rotor shaft section. This means, for example, that the first rotor shaft section and the second rotor shaft section can be designed as coaxially spaced cylinders, and the (nominal) gap is filled with insulating material whose shear strength is sufficient to transmit the motor torque.

[0020] According to a preferred embodiment, the first rotor shaft section can be configured to be connected / coupled to a gearbox input shaft for power transmission, in particular for torque transmission. This means that the first rotor shaft section is arranged closer to the gearbox input shaft than the second rotor shaft section.

[0021] According to a preferred embodiment, the first rotor shaft section can have or form a gear section which is configured to be connected to a gear section of the transmission input shaft in a force-transmitting manner.

[0022] According to a preferred embodiment, the electrically insulated connection between the gear section of the first rotor shaft section and the second rotor shaft section can be formed.

[0023] According to a preferred embodiment, the first rotor shaft section can be electrically isolated from the rotor. In particular, the first rotor shaft section can be in no direct contact with the rotor, for example, it can be arranged axially outside the rotor, at least partially. In a region of the first rotor shaft section arranged axially inside the rotor, it can be arranged radially inside the second rotor shaft section and, in particular, be electrically isolated from the second rotor shaft section or the rotor by means of the insulating material.

[0024] According to a preferred embodiment, the rotor shaft can be rotatably mounted via a first bearing and a second bearing. Preferably, the first bearing can be arranged on the first rotor shaft section. Preferably, the second bearing can be arranged on the second rotor shaft section. The first bearing can be arranged, in particular, on one axial side of the rotor, especially axially outside the rotor. The second bearing can be arranged, in particular, on the other axial side of the rotor, especially axially outside the rotor. This ensures stable mounting.

[0025] According to a preferred embodiment, the second bearing can be electrically insulated. This means that the second bearing is a current-insulating rotary bearing. Therefore, no currents can be introduced into the second rotor shaft section via the second bearing.

[0026] According to a preferred embodiment, the second bearing can be a rolling bearing with an inner ring, an outer ring, and a plurality of rolling elements guided between the inner ring and the outer ring. Preferably, the inner ring and / or the outer ring can have a current-insulating coating, preferably a ceramic coating. In particular, the plurality of rolling elements can be made of a current-insulating material, preferably ceramic.

[0027] Furthermore, the first bearing can be electrically insulated. This means that the first bearing is a current-isolating rotary bearing. This means that no current can be introduced into the first rotor shaft section via the first bearing.

[0028] According to one embodiment, the first bearing can be a rolling bearing with an inner ring, an outer ring, and a plurality of rolling elements guided between the inner ring and the outer ring. Preferably, the inner ring and / or the outer ring can have a current-insulating coating, preferably a ceramic coating. In particular, the plurality of rolling elements can be made of a current-insulating material, preferably ceramic.

[0029] According to a preferred embodiment, the rotating machine can have at least one grounding element. This ensures targeted current dissipation. According to a preferred embodiment, the grounding element can be connected to / in contact with the second rotor shaft section. This ensures targeted current dissipation in the area of ​​the second rotor shaft section.

[0030] The invention also relates to a geared motor unit comprising the electric rotary machine and a gearbox, the gearbox input shaft of which is coupled or can be coupled to the first rotor shaft section of the rotor shaft of the electric rotary machine for torque transmission.

[0031] In other words, the invention relates to a rotor design, in particular the electrical insulation of a rotor, preferably of a radial flux machine, to improve electromagnetic compatibility and reduce induced currents. The rotor is electrically isolated by an insulated coupling between parts of a rotor shaft, which includes an electrically insulating layer between the parts. The electrically insulating layer is capable of transmitting a mechanical force. One possible embodiment is a design with two (plug-in) gears, each of which has a nominal air gap filled with an insulating material, e.g., plastic. Furthermore, an insulated rotor bearing and / or an additional grounding element can be provided.

[0032] The invention is explained below with the aid of drawings. These show:

[0033] Fig. 1 shows a partial sectional view of a rotary machine or geared motor unit according to a preferred embodiment of the invention.

[0034] Fig. 2 shows a cross-sectional view of a rotor shaft of the rotary machine,

[0035] Figs. 3 to 7 show further possible designs of a cross-section of the rotor shaft, and Figs. 8 to 10 show yet another possible design of the rotor shaft.

[0036] The figures are purely schematic and serve solely to illustrate the invention. The same elements are identified by the same reference symbols.

[0037] Fig. 1 is a partial sectional view of a rotary machine 1 or geared motor unit 2 according to the invention. The rotary machine 1 is a component of the geared motor unit 2 according to the invention.

[0038] Rotary machine 1 is an electric rotary machine. Rotary machine 1 is specifically designed as a radial flux machine.

[0039] The rotary machine 1 has a rotor shaft 3 and a rotor 4 attached to / arranged on the rotor shaft 3. The rotor shaft 3 is multi-part, meaning that the rotor shaft 3 is formed (at least) by a first rotor shaft section 5 and a separate second rotor shaft section 6. In particular, the first rotor shaft section 5 and the second rotor shaft section 6 are arranged coaxially.

[0040] The first rotor shaft section 5 and the second rotor shaft section 6 are connected via an electrically insulated connection / coupling 7 for power transmission, in particular for torque transmission. The (two) rotor shaft sections 5, 6 are connected to other components for torque transmission and are electrically insulated from each other.

[0041] The electrically insulated connection / coupling 7 can be formed by a positive-locking connection. In Fig. 2, the coupling 7 is formed by a splined connection 8. Other possible configurations of the coupling 7, which can be used as alternatives to the splined connection 8, are described below with reference to Figs. 3 to 7. The splined connection 8 transmits torque between the first rotor shaft section 5 and the second rotor shaft section 6. In particular, the splined connection 8 forms a permanent force-transmitting connection (i.e., non-switchable / non-disconnectable during operation) between the first rotor shaft section 5 and the second rotor shaft section 6.

[0042] Preferably, the splined connection 8 can be formed by a first coupling part / socket part 9 formed (in particular integrally) on the first rotor shaft section 5 and a second coupling part / socket part 10 formed (in particular integrally) on the second rotor shaft section 6. For example, the first splined connection part 9 can be an external tooth and the second splined connection part 10 can be an internal tooth. This means that the first rotor shaft section 5 and the second rotor shaft section 6 are arranged radially nested section by section, namely in the area of ​​the electrically insulated connection / coupling 7 or the splined connection 8.

[0043] Preferably, the first splined section 9 and the first splined section 10 can be spaced apart by a (radial) gap 11, i.e., by a nominal air gap (see also Fig. 2). In particular, an insulating material / layer 12 can be arranged in the gap 11 between the first splined section 9 and the second splined section 10, or the gap 11 can be (completely) filled with the insulating material 12. This means that the first splined section 9 and the second splined section 10 are radially separated from each other by the insulating material 12. The (electrically) insulating material 12 (or the electrically insulating layer) is designed to transmit a mechanical force. The insulating material 12 can preferably be a plastic.

[0044] Furthermore, the first rotor shaft section 5 and the second rotor shaft section 6 can be spaced apart by an (axial) gap 13. In particular, an insulating material / layer 14 can be arranged in the gap 13 between the first rotor shaft section 5 and the second rotor shaft section 6, or the gap 13 can be (completely) filled with the insulating material 14. This means that the first rotor shaft section 5 and the second rotor shaft section 6 are axially separated from each other by the insulating material 14. The (electrically) insulating material 14 (or the electrically insulating layer) is designed to transmit a mechanical force. The insulating material 14 can preferably be a plastic.

[0045] Figure 1 shows the geared motor unit 2. The geared motor unit 2 comprises the rotary machine 1 and a gearbox 15. The gearbox 15 has a gearbox input shaft 16.

[0046] Preferably, the first rotor shaft section 5 can be connected / coupled or connectable / coupled to the transmission input shaft 16 in a force-transmitting manner, in particular a torque-transmitting manner, or be configured to be connected / coupled to the transmission input shaft 16 in a force-transmitting manner, in particular a torque-transmitting manner. This means that the first rotor shaft section 5 is arranged closer to the transmission input shaft 16 than the second rotor shaft section 6.

[0047] In particular, the first rotor shaft section 5 can be electrically isolated from the rotor 4. Specifically, the first rotor shaft section 5 can not be in direct contact with the rotor 4, for example, it can be arranged axially outside the rotor 4, at least partially. In a region of the first rotor shaft section 5 arranged axially inside the rotor 4, it can be arranged radially inside the second rotor shaft section 6 and, in particular, be electrically isolated from the second rotor shaft section 6 or the rotor 4 via the electrically insulated connection 7 or the insulating material 12.

[0048] Preferably, the rotor shaft 3 can be rotatably mounted via a first bearing 17 and a second bearing 18. Preferably, the first bearing 17 can be arranged on the first rotor shaft section 5. Preferably, the second bearing 18 can be arranged on the second rotor shaft section 6.

[0049] In particular, the second bearing 18 can be electrically insulated. That is, the second bearing 18 is a current-insulating rotary bearing. For example, the second bearing 18 can be a rolling bearing with an inner ring, an outer ring, and a plurality of rolling elements guided between the inner ring and the outer ring. Preferably, the inner ring and / or the outer ring can have a current-insulating coating, preferably a ceramic coating. In particular, the plurality of rolling elements can be made of a current-insulating material, preferably ceramic.

[0050] Furthermore, the first bearing 17 can be electrically insulated. That is, the first bearing 17 is a current-insulating rotary bearing. For example, the first bearing 17 can be a rolling bearing with an inner ring, an outer ring, and a plurality of rolling elements guided between the inner ring and the outer ring. Preferably, the inner ring and / or the outer ring can have a current-insulating coating, preferably a ceramic coating. In particular, the plurality of rolling elements can be made of a current-insulating material, preferably ceramic.

[0051] Preferably, the rotating machine 1 can have at least one grounding element 19. In particular, the grounding element 19 can be connected to / in contact with the second rotor shaft section 6.

[0052] The rotary machine 1 also has a stator 20. The stator 20 and the rotor 4 are arranged radially nested. In the illustrated embodiment, the rotor 4 is arranged radially inside the stator 20.

[0053] Figures 3 to 7 show further possible embodiments of the coupling 7, which can be used as alternatives to the splined connection 8 shown in Figure 2 and described above. Figure 3 shows an embodiment of the coupling 7 in which the first rotor shaft section 5, or the first coupling part 9, is formed with an (external) toothed section, and the second rotor shaft section 6, or the second coupling part 10, is formed with a circular inner diameter. This means that the first coupling part 9 and the second coupling part 10 can also have different cross-sections as coupling geometries. Between the first coupling part 9 and the second coupling part

[0054] 10 the gap 11 is formed, which is filled with the insulating material 12.

[0055] Alternatively, the first coupling part 9 could have a circular inner diameter and the second coupling part 10 could have internal teeth, although this is not shown. Another alternative option would be a different positive-locking cross-sectional geometry instead of teeth, although this is not shown.

[0056] Fig. 4 shows an embodiment of the coupling 7 in which the first rotor shaft section 5 or the first coupling part 9 and the second rotor shaft section 6 or the second coupling part 10 each have a triangular cross-sectional geometry, in particular an equilateral triangle. A gap 11, filled with the insulating material 12, is formed between the first coupling part 9 and the second coupling part 10.

[0057] Fig. 5 shows an embodiment of the coupling 7 in which the first rotor shaft section 5 or the first coupling part 9 and the second rotor shaft section 6 or the second coupling part 10 each have a quadrilateral, in particular square, cross-sectional geometry as coupling geometries. The gap between the first coupling part 9 and the second coupling part 10 is

[0058] 11 formed, which is filled with the insulating material 12.

[0059] Fig. 6 shows an embodiment of the coupling 7, in which the first rotor shaft section 5 or the first coupling part 9 and the second rotor shaft section 6 or the second coupling part 10 each have a positive-locking geometry in cross-section, essentially a polygonal, preferably quadrilateral, in particular square geometry with rounded corners. A gap 11 is formed between the first coupling part 9 and the second coupling part 10, which is filled with the insulating material 12.

[0060] Fig. 7 shows an embodiment of the coupling 7 in which the first rotor shaft section 6 (or first coupling part 9) and the second rotor shaft section 6 (or second coupling part 10) each have a circular cross-sectional geometry. This means that the first coupling part 9 and the second coupling part 10 are each designed as circular (hollow) cylinders, radially spaced and coaxially arranged. A gap 11, filled with the insulating material 12, is formed between the first coupling part 9 and the second coupling part 10.

[0061] Figures 8 to 10 show another possible embodiment of the rotor shaft 3.

[0062] The design of Figs. 8 to 10 is, with the exception of the modifications described below, identical to the previously described designs or embodiments of Figs. 1 to 7, so that with regard to further features of this design reference is made to Figs. 1 to 7 and their description.

[0063] According to the design of the rotor shaft 3 in the figures 8 to 10, the first rotor shaft section 5 has a gear section or is designed as the gear section which is arranged to be connected to a gear section of the transmission input shaft 16 in a force-transmitting manner.

[0064] The electrically insulated connection between the first rotor shaft section 5 and the second rotor shaft section 6 is formed between the gear section of the first rotor shaft section (5) and the second rotor shaft section (6). The electrically insulated connection is preferably formed similarly to the preceding embodiments, preferably by means of the (radial) gap 11 and the insulating material 12 inserted into the (radial) gap 11.

[0065] List of reference signs

[0066] Rotary machine

[0067] Geared motor unit

[0068] Rotor shaft

[0069] Rotor, first rotor shaft section, second rotor shaft section, electrically insulated connection / coupling

[0070] Splined connection first coupling part / spewing connection second coupling part / spewing connection

[0071] (Radial) gap insulating material

[0072] (Axial) gap insulating material

[0073] transmission

[0074] Gearbox input shaft first bearing second bearing

[0075] grounding element

[0076] stator

Claims

Patent claims 1. Electric rotary machine (1), in particular a radial flux machine, with a rotor shaft (3) and a rotor (4) attached to the rotor shaft (3), characterized in that the rotor shaft (3) is formed by a first rotor shaft section (5) and a second rotor shaft section (6) separate from it, wherein the first rotor shaft section (5) and the second rotor shaft section (6) are connected by an electrically insulated connection (7) to transmit power.

2. Rotary machine (1 ) according to claim 1 , characterized in that the first rotor shaft section (5) and the second rotor shaft section (6) are connected in a torque-transmitting manner via a first coupling part (9) formed on the first rotor shaft section (5) and a second coupling part (10) formed on the second rotor shaft section (6), wherein the first coupling part (9) and the second coupling part (10) are spaced apart by a gap (11 ).

3. Rotary machine (1 ) according to claim 2, characterized in that the gap (11 ) is filled with an insulating material (12).

4. Rotary machine (1 ) according to claim 2 or 3, characterized in that the first coupling part (9) and the second coupling part (10) form a positive locking connection.

5. Rotary machine (1) according to claim 3, characterized in that the first coupling part (9) and the second coupling part (10) form a purely friction-fit connection and / or a purely material-fit connection, wherein the insulating material (12) is selected such that a shear strength of the insulating material (12) for torque transmission is suitable between the first rotor shaft section (5) and the second rotor shaft section (6).

6. Rotary machine according to one of claims 1 to 5, characterized in that the first rotor shaft section (5) is arranged to be connected to a transmission input shaft (16) in a force-transmitting manner and is electrically insulated from the rotor (4).

7. Rotary machine (1 ) according to claim 6, characterized in that the first rotor shaft section (5) has or forms a gear section which is arranged to be connected to a gear section of the transmission input shaft (16) in a force-transmitting manner.

8. Rotary machine according to claim 7, characterized in that the electrically insulated connection (7) is formed between the gear section of the first rotor shaft section (5) and the second rotor shaft section (6).

9. Rotary machine (1 ) according to one of claims 1 to 8, characterized in that the rotor shaft (3) is rotatably mounted via a first bearing (17) and a second bearing (18), wherein the first bearing (17) is arranged on the first rotor shaft section (5) and the second bearing (18) is arranged on the second rotor shaft section (6), wherein the second bearing (18) is electrically insulated.

10. Rotary machine (1 ) according to claim 9, characterized in that the second bearing (18) is a rolling bearing with an inner ring, an outer ring and a plurality of rolling elements guided between the inner ring and the outer ring, wherein the inner ring and / or the outer ring has a current-insulating coating and / or wherein the plurality of rolling elements is made of a current-insulating material.

11. Rotary machine (1) according to one of claims 1 to 10, characterized in that the rotary machine (1) has at least one grounding element (19) which is connected to the second rotor shaft section (6).

12. Geared motor unit (2), comprising an electric rotary machine (1) according to one of claims 1 to 11 and a gearbox (15) whose gearbox input shaft (16) is coupled or can be coupled to the first rotor shaft section (5) of the rotor shaft (3) of the electric rotary machine (1) for torque transmission.

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