Axial flux machine for motor vehicle, in particular for motor vehicle

Abstract

The invention relates to an axial flux machine (10) for a motor vehicle, comprising a stator (12), a first rotor (14) that can be rotated relative to the stator (12) about a machine axis of rotation and a second rotor (16) that can be rotated relative to the stator (12) about the machine axis of rotation, the stator (12) being arranged between the rotors (14, 16) in the axial direction of the axial flux machine (10), the rotors (14, 16) being arranged between the rotors (12, 16) by means of a first rotor (14) arranged between the first rotor (14) and the second rotor (16) arranged between the first rotor (14) and the second rotor (16). According to the invention, the respective teeth (18, 20) of the rotors (14, 16) facing each other in the axial direction of the axial flux machine (10) on the end faces (S1, S2) of the rotors (14, 16) are connected to each other at least indirectly in a rotationally fixed manner, the respective teeth (18, 20) are arranged at or on the respective circular ring surfaces of the respective end faces (S1, S2), the respective teeth (18, 20) are arranged concentrically to the machine axis of rotation, and the rotors (14, 16) and thus the teeth (18, 20) are connected to each other in a rotationally fixed manner by means of the teeth (18, 20) which are arranged radially on the end faces (S1, S2) of the rotors (14, 16). The spiral bushings (26), which are arranged in the axial flow machine (10) and concentric to the machine axis of rotation and which have differential threads (28), are clamped against each other in the axial direction of the axial flow machine (10).

Description

Field of the Invention

[0001] The present invention relates to an axial flux machine for a motor vehicle, in particular for an automobile, according to the preamble of patent claim 1. Background Art

[0002] For example, such an axial flux machine for a motor vehicle, in particular for an automobile, has been disclosed in DE 10 2020 114 855 B3. The axial flux machine has a stator and a first rotor rotatable relative to the stator about a machine rotation axis. In addition, the axial flux machine has a second rotor rotatable relative to the stator about the machine rotation axis. For example, the rotor can be driven by the stator and thus can rotate relative to the stator about the machine rotation axis. The stator is arranged axially between the rotors along the axial direction of the axial flux machine. Summary of the Invention

[0003] The object of the present invention is to improve an axial flux machine of the above type.

[0004] This object is achieved by an axial flux machine having the features of patent claim 1. Advantageous designs with suitable improvements of the present invention are given in the remaining claims.

[0005] To improve an axial flux machine of the type described in the preamble of patent claim 1, according to the present invention, the rotors are at least indirectly torsionally resistant to each other by means of corresponding tooth portions of the rotors arranged on the end faces of the rotors facing each other in the axial direction of the axial flux machine. In this case, the corresponding tooth portions are arranged in or on corresponding circular ring surfaces of the corresponding end faces. The corresponding tooth portions are arranged concentrically with the machine rotation axis. For example, the stator can have a through hole, in particular along the axis of the electric machine, and thus when viewed along the machine rotation axis, the tooth portions are arranged in the through hole. In addition, it is conceivable that the first rotor and the second rotor, in particular the first rotor bracket of the first rotor and the second rotor bracket of the second rotor, are identical in terms of basic structure, i.e., identical and / or mirror-symmetrical. In addition, it is conceivable that the rotors are different from each other due to machining and / or due to the tooth portions and / or due to cooling and / or due to imbalance compensation, and are preferably mirror-symmetrical and / or identical in other respects, i.e., identical in structure.

[0006] According to the present invention, it is also provided that the rotors and thus the resulting tooth portions are clamped to each other in the axial direction of the axial flux machine by a helical bushing arranged radially in the rotors and arranged concentrically with the machine rotation axis and having a differential thread.

[0007] In an advantageous design of the present invention, the first differential thread portion of the differential thread and the second differential thread portion of the differential thread are configured as fine threads.

[0008] In an advantageous design of the present invention, the first differential thread portion meshes with the corresponding third thread portion of the first rotor, and the second differential thread portion meshes with the corresponding fourth thread portion of the second rotor.

[0009] In an advantageous design of the present invention, the first differential thread portion of the differential thread meshes with the corresponding third thread portion of the first rotor, and the second differential thread portion meshes with the corresponding fourth thread portion of the transmission shaft.

[0010] In an advantageous design of the present invention, a locking sleeve is provided, which is arranged concentrically with the machine rotation axis, axially adjacent to the spiral bushing and located on the axially opposite side of the transmission shaft, wherein the locking sleeve has a thread with a thread rotation direction opposite to that of the differential thread.

[0011] In an advantageous design of the present invention, the rotor is formed of rotor steel having a high carbon content, wherein the transmission shaft is formed of chrome molybdenum steel.

[0012] In an advantageous design of the present invention, the transmission shaft is connected to one of the rotors by two additional meshing tooth portions.

[0013] In an advantageous design of the present invention, an intermediate shaft made of chrome molybdenum steel is provided between the two rotors.

[0014] In an advantageous design of the present invention, the tooth portion is configured as a Hirth tooth portion.

[0015] The above-mentioned chrome steel and molybdenum steel are also referred to as chrome molybdenum steel. In particular, the rotor steel is cost-intensive, especially compared to chrome molybdenum steel, especially per unit weight, so chrome molybdenum steel is cheaper than rotor steel. The background in this regard can especially be that a laminate is provided for the rotor magnetic field, which is formed, for example, by wound thin and narrow metal strips, or includes wound thin and narrow metal strips, and the laminate or metal strips can be arranged as a layer adjacent to the permanent magnet of the axial flux machine. For example, the laminate is welded to the rotor steel.

[0016] In summary, it can be seen that the rotor (also designated as a rotor half or rotor element or configured as a rotor half or rotor element) is preferably clamped to each other axially of the motor by means of, in particular, an internal spiral bushing (preferably configured as a threaded bushing) and by means of a differential thread, that is, especially relative to each other, whereby, in particular, tooth portions preferably configured as Hirth tooth portions are clamped to each other axially of the axial flux machine, that is, relative to each other, especially at least indirectly or directly. In particular, the present invention can at least achieve the following advantages:

[0017] - The assembly is simpler compared to traditional solutions.

[0018] - The machining cost of the rotor is lower compared to traditional solutions,

[0019] - The two rotors can be at least almost identical and can thus be configured as identical components, with the result that the manufacturing cost can be kept particularly low,

[0020] - The degree of imbalance is lower compared to traditional solutions,

[0021] - The symmetry of the rotor results in the two rotor halves having the same vibration behavior, thus eliminating the tuning of the axial natural frequency,

[0022] - Fewer components,

[0023] - For the respective rotor, no welded joints are required, so there is no thermal deformation, and there is less imbalance, which results in better noise behavior, also known as NVH behavior,

[0024] - No welded joints with the drive shaft are required,

[0025] - No sealing of the toothing is required. Description of the Drawings

[0026] Other advantages, features, and details of the present invention will become apparent from the following description of the preferred embodiments and with reference to the drawings. Without departing from the scope of the present invention, the above-mentioned features and combinations of features mentioned in the description, as well as the features and combinations of features mentioned in the description of the drawings and / or shown individually in the drawings, can be used not only in the respective combinations but also in other combinations or individually.

[0027] In the drawings:

[0028] Figure 1 A part of a schematic longitudinal sectional view of a first embodiment of an axial flux machine for a motor vehicle, in particular for an automobile, is shown;

[0029] Figure 2 A part of a schematic longitudinal sectional view of a second embodiment of the axial flux machine is shown;

[0030] Figure 3 A part of a schematic longitudinal sectional view of a third embodiment of the axial flux machine is shown; and

[0031] Figure 4 A part of a schematic longitudinal sectional view of a fourth embodiment of the axial flux machine is shown.

[0032] In the figures, identical or functionally identical elements have the same reference numerals. Detailed Description

[0033] Figure 1A first embodiment of an axial flux machine 10 for a motor vehicle, in particular for an automobile, is shown as part of a schematic longitudinal sectional view. The axial flux machine 10 has a stator, a first rotor 14 and a second rotor 16, wherein the rotors 14 and 16 are rotatable relative to the stator 12 about a common machine axis of rotation. In particular, the rotors 14 and 16 can be driven by the stator 12 so as to rotate relative to the stator 12 about the machine axis of rotation. As can be seen from Figure 1 it that, when viewed in the axial direction of the axial flux machine 10, thus along the machine axis of rotation, the stator 12 is at least partially arranged between the rotors 14 and 16, and the rotors 14 and 16 are also referred to as rotor halves or rotor elements. The axial flux machine 10 is an electric machine configured as an axial flux machine, wherein the axial flux machine 10 is also referred to as an axial flux motor.

[0034] In order to be able to manufacture the axial flux machine 10 in a particularly simple manner, thus particularly time-saving and cost-effective manner, in the axial flux machine 10, the rotors 14 and 16 are at least indirectly torsionally connected to each other by respective tooth portions 18 and 20 of the rotors 14 and 16 that face each other in the axial direction of the axial flux machine 10 and are arranged on the end faces S1 and S2 of the rotors 14 and 16. In Figure 1 the first embodiment shown, the tooth portions 18 and 20 directly mesh with each other, so that in the first embodiment, the rotors 14 and 16 are directly torsionally connected to each other by the tooth portions 18 and 20. The respective tooth portions 18, 20 are provided in or on the respective circular ring surfaces of the respective end faces S1, S2. In addition, the respective tooth portions 18, 20 are arranged concentrically with the machine axis of rotation.

[0035] Figure 1 A drive shaft 22 is also shown. The drive shaft 22 is separately constructed from the rotors 14 and 16 and is torsionally connected to the rotor 14, so that the drive shaft 22 is also torsionally connected to the rotor 16 through the rotor 14. In this case, the drive shaft is connected to the rotor 14 by a welded joint 24, that is, a welded connection to the rotor 14, thereby torsionally connecting the drive shaft 22 to the rotor 14. The respective rotors 14, 16 are formed of a first steel, for example, and the first steel is also referred to as rotor steel. For example, the first steel is EN 24T. The drive shaft 22 is formed of a second steel different from the first steel, and the second steel is preferably chrome molybdenum steel. In particular, the second steel can be 20MoCr4.

[0036] In a first embodiment, the rotors 14 and 16 and thus the tooth portions 18 and 20 are clamped to each other axially of the axial flux machine 10 by a helical bushing 26, which is arranged radially within the rotors 14 and 16, i.e. radially of the axial flux machine 10, and is arranged or extends or is configured concentrically with respect to the machine rotation axis. The helical bushing 26 is also referred to as a threaded bushing. For example, the helical bushing 26 is formed of a second steel. The helical bushing 26 is constructed separately from the rotors 14 and 16 and separately from the drive shaft 22. In the first embodiment, the drive shaft 22 is the shaft of a planetary gear set. The planetary gear set has, for example, a sun gear that is torsionally connected to the drive shaft 22. Thus, the drive shaft 22 is the sun shaft.

[0037] As can be seen, Figure 1 the helical bushing 26 has a differential thread 28, which has a first differential thread portion 30 and a second differential thread portion 32. For example, the differential thread portions 30 and 32 are configured as fine threads. The first differential thread portion 30 has a first thread pitch, also referred to as a first pitch, and the second differential thread portion 32, also simply referred to as the second thread portion, has a second thread pitch different from the first thread pitch, also simply referred to as a second pitch. For example, the second thread pitch differs from the first thread pitch by at most 10%, in particular by 10% from the first thread pitch, or vice versa.

[0038] In the first embodiment, the first differential thread portion 30 meshes particularly directly with a corresponding third thread portion 34 of the first rotor 14, wherein the second differential thread portion 32 meshes particularly directly with a corresponding fourth thread portion 36 of the rotor 16. This means that the differential thread portion 30 is screwed particularly directly onto the thread portion 34, and the differential thread portion 32 is screwed particularly directly onto the thread portion 36.

[0039] Figure 2A second embodiment of the axial flux machine 10 is shown as part of a schematic longitudinal sectional view. The second embodiment differs particularly from the first embodiment in that, in the first embodiment, the tooth portions 18 and 20 mesh directly with each other, i.e., directly engage with each other, while in the second embodiment, the tooth portions 18 and 20 do not mesh directly with each other. Thus, in the second embodiment, the rotors 14 and 16 are indirectly torsionally connected to each other via the tooth portions 18 and 20. In the second embodiment, a spacer ring 38 is provided, which is arranged axially between the tooth portions 18 and 20 along the axial direction of the axial flux machine 10. In particular, the spacer ring 38 is formed of a second steel. The spacer ring 38 has a third tooth portion 40 corresponding to the tooth portion 18, which meshes directly with the tooth portion 18 and thus directly engages with the tooth portion 18. In addition, the spacer ring 38 has a fourth tooth portion 42 corresponding to the second tooth portion 20, which meshes directly with the tooth portion 20 and thus directly engages with the tooth portion 20. Thus, in the second embodiment, the rotors 14 and 16 are connected to each other via the tooth portions 18, 20, 40 and 42 and are indirectly torsionally connected to each other. For example, the tooth portions 18 and 20 are configured as Hirth tooth portions, such that the tooth portions 40 and 42 are also preferably configured as Hirth tooth portions.

[0040] Figure 3 A third embodiment of the axial flux machine 10 is shown as part of a schematic longitudinal sectional view. The third embodiment differs particularly from the second embodiment in that the third thread portion 34 corresponding to the differential thread portion 30 is not a thread portion of the rotor 14, but a thread portion of the transmission shaft 22 and is thus provided on the transmission shaft 22.

[0041] Finally, Figure 4 A part of a schematic longitudinal sectional view of a fourth embodiment of the axial flux machine 10 is shown. The fourth embodiment differs particularly from the third embodiment in that, although the same spacer ring 38 as in the second embodiment is provided in the third embodiment, the spacer ring 38 is omitted in the fourth embodiment. Thus, in the fourth embodiment, the rotors 14 and 16 are directly torsionally connected to each other via the tooth portions 18 and 20, because in the fourth embodiment, the tooth portions 18 and 20 mesh directly with each other.

[0042] From Figures 1 to 4 it can be seen that the stator 12 has a through hole 45, which is through in the axial direction of the axial flux machine 10. At least in the first embodiment and the fourth embodiment, the tooth portions 18 and 20 are arranged in the through hole 45, particularly in such a way that, when viewed from the outside, the tooth portions 18 and 20 are overlapped and thus covered by the stator 12 in the radial direction of the axial flux machine 10. In the second and third embodiments, it is also conceivable that the corresponding tooth portions 18, 20 are at least partially arranged in the through hole 45 of the stator 12.

[0043] The third and fourth embodiments also differ particularly from the first and second embodiments, in which the drive shaft 22 is torsionally connected to the rotor 14 by additional tooth portions 44 and 46. In this case, the tooth portions 44 and 46 are arranged on the end faces of the drive shaft 22 and the rotor 14, facing each other in the axial direction of the axial flux machine 10. In this case, for example, the tooth portion 44 of the drive shaft 22 configured as a Hirth tooth portion and the tooth portion 46 of the rotor 14 directly mesh with each other. In this case, the tooth portion 18 is arranged, for example, on the end face S1 which is the first end face of the rotor 14, and the tooth portion 46 of the rotor 14 is arranged, for example, on the third end face of the rotor 14. The third end face of the rotor 14 is, for example, away from the first end face S1 in the axial direction of the axial flux machine 10 and thus faces away from the first end face S1. The end face of the drive shaft 22 on which the tooth portion 42 is arranged is also referred to as, for example, the fourth end face, which faces the third end face in the axial direction of the axial flux machine 10.

[0044] List of reference signs

[0045] 10 Axial flux machine

[0046] 12 Stator

[0047] 14 First rotor

[0048] 16 Second rotor

[0049] 18 Tooth portion

[0050] 20 Tooth portion

[0051] 22 Drive shaft

[0052] 24 Welded joint

[0053] 26 Spiral bushing

[0054] 28 Differential thread

[0055] 30 First thread portion

[0056] 32 Second thread portion

[0057] 34 Third thread portion

[0058] 36 Fourth thread portion

[0059] 38 Spacer ring

[0060] 40 Tooth portion

[0061] 42 Tooth portion

[0062] 44 Tooth portion

[0063] 45 Through hole

[0064] 46-tooth part

Claims

1. An axial flux machine (10) for a motor vehicle, comprising a stator (12), a first rotor (14) rotatable relative to the stator (12) about a machine rotation axis, and a second rotor (16) rotatable relative to the stator (12) about the machine rotation axis, wherein, the stator (12) is arranged between the rotors (14, 16) in the axial direction of the axial flux machine (10), characterized in that, - the rotors (14, 16) are at least indirectly torsionally connected to each other by respective tooth portions (18, 20) of the rotors (14, 16) arranged on end faces (S1, S2) of the rotors (12, 14) and facing each other in the axial direction of the axial flux machine (10); - the respective tooth portions (18, 20) are provided in or on respective circular ring surfaces of the respective end faces (S1, S2); - the respective tooth portions (18, 20) are arranged concentrically with the machine rotation axis; and - the rotors (14, 16) and thus the tooth portions (18, 20) are clamped against each other in the axial direction of the axial flux machine (10) by a helical bushing (26) arranged radially within the rotors (14, 16), arranged concentrically with the machine rotation axis, and having a differential thread (28).

2. The axial flux machine (10) according to claim 1, characterized in that, a first differential thread portion (30) of the differential thread (28) and a second differential thread portion (32) of the differential thread (28) are configured as fine threads.

3. The axial flux machine (10) according to claim 2, characterized in that, the first differential thread portion (30) meshes with a respective third thread portion (34) of the first rotor (14), and the second differential thread portion (32) meshes with a respective fourth thread portion (36) of the second rotor (16).

4. The axial flux machine (10) according to claim 2, characterized in that, the first differential thread portion (30) of the differential thread (28) meshes with a respective third thread portion (34) of the first rotor (14), and the second differential thread portion (32) meshes with a respective fourth thread portion (36) of a transmission shaft (22).

5. The axial flux machine (10) according to claim 4, characterized in that, a locking sleeve is provided, which is arranged concentrically with the machine rotation axis, axially adjacent to the helical bushing (26) and on an axially opposite side of the transmission shaft (22), wherein the locking sleeve has a thread with a thread rotation direction opposite to that of the differential thread (28).

6. The axial flux machine (10) according to claim 4 or 5, characterized in that, the rotors (14, 16) are formed of rotor steel having a high carbon content, wherein the transmission shaft (22) is formed of chrome molybdenum steel.

7. The axial flux machine (10) according to any one of claims 4 to 6, characterized in that, The drive shaft (22) is connected to one of the rotors (14, 16) by two further meshing tooth portions (44, 46).

8. The axial flux machine (10) according to any one of the preceding claims, characterized in that an intermediate shaft (38) made of chrome molybdenum steel is provided between the two rotors (14, 16).

9. The axial flux machine (10) according to any one of the preceding claims, characterized in that the tooth portions (18, 20) are configured as Hirth tooth portions.

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