Rotor and manufacturing method thereof, axial flow motor and motor vehicle

Abstract

The invention relates to a rotor for an axial-flow electric machine, comprising: a permanent magnet assembly for generating a magnetic flux, the permanent magnet assembly having a plurality of permanent magnets (6); a flux-conducting carrier (2) having two axially opposite end faces (4, 5), at least one of which has a plurality of support regions (7) on which the permanent magnets are fixed; and a bandage device for receiving a force acting on each permanent magnet, the bandage device having a plurality of bandages (14) which extend through the carrier in the axial direction and extend on the permanent magnets on the end faces, the bandages being used for fixing the permanent magnets on the associated support regions and for receiving a force acting on the permanent magnets in the axial direction, for this purpose, the carrier has a plurality of axial perforations (17), through which the bandages pass and in this case bind the permanent magnets and the carrier region. The invention also relates to a rotor manufacturing method, an axial flow motor and a motor vehicle.

Description

Technical Field

[0001] The present invention relates to a rotor for an axial flow motor. The rotor has a permanent magnet assembly for generating a magnetic flux, the permanent magnet assembly having a plurality of permanent magnets, and the rotor has a carrier for guiding the magnetic flux, the carrier having two end sides opposite to each other in the axial direction, at least one of the two end sides having a plurality of bearing areas, and the permanent magnets of the permanent magnet assembly are fixed on these bearing areas. In addition, the rotor has a bandage device for receiving forces acting on the permanent magnets. The present invention also relates to a method for manufacturing a rotor, an axial flow motor and a motor vehicle. Background Art

[0002] At present, the axial flow motor for motor vehicles is of interest, which can be used, for example, as a drive motor for an electric vehicle or a hybrid vehicle. Such an axial flow motor usually has at least one rotor and at least one stator, which are arranged adjacent to each other in the axial direction while forming at least one air gap. The axially extending rotor shaft is here connected to the carrier of the rotor in a rotationally fixed manner. The at least one stator usually has a stator winding that can be energized, which is used to generate an axially oriented stator flux. In the case of an axial flow motor with permanent magnet excitation, the rotor also has a permanent magnet assembly for generating an axially oriented rotor flux, which has a plurality of permanent magnets. These permanent magnets can be configured as surface magnets and fixed, for example, bonded, on at least one end surface of the carrier. In the operation of the axial flow motor, in particular, the permanent magnets are subjected to forces due to the rotation of the rotor, and the permanent magnets may be loosened from the carrier due to the forces. For this reason, it is known from the prior art, for example, from EP3480930A1, to equip the rotor with a bandage device. The bandage device radially surrounds the permanent magnet in order to absorb the centrifugal forces acting radially on the permanent magnet during operation.

[0003] However, during operation of the axial-flow motor, it may also happen that the radially outer region of the carrier is deflected in the axial direction, and in this case the permanent magnets in the radially inner region of the carrier are lifted axially in the direction of the stator. However, this cannot be avoided according to the prior art by a bandage device that radially surrounds the permanent magnets. In order to avoid axial lifting of the permanent magnets, the axial-flow motors known from the prior art are limited in their maximum rotational speed. Summary of the invention

[0004] The object of the present invention is to design the mechanical connection between the carrier and the permanent magnets of the rotor of an axial-flow electric machine in a particularly reliable and stable manner.

[0005] This object is achieved according to the invention by a rotor, a method for producing a rotor, an axial-flow electric machine and a motor vehicle having the features according to the respective independent claims. Advantageous embodiments of the invention are the subject matter of the dependent claims, the description and the drawings.

[0006] The rotor for an axial-flow motor according to the present invention has a permanent magnet assembly for generating a magnetic flux, the permanent magnet assembly having a plurality of permanent magnets, and the rotor has a carrier for guiding the magnetic flux, the carrier having two end sides opposite to each other in the axial direction. At least one of the two end sides of the carrier has a plurality of bearing areas, on which the permanent magnets are fixed. In addition, the rotor includes a bandage device for receiving forces acting on the permanent magnets. The bandage device has a plurality of bandages extending through the carrier in the axial direction and extending on the permanent magnets on the end sides, the bandages being used to fix the permanent magnets on the assigned bearing areas and for receiving forces acting on the permanent magnets in the axial direction. For this purpose, the carrier has a plurality of axial through-holes, each bandage passing through the through-holes and in this case bundling the permanent magnets and the corresponding assigned bearing areas.

[0007] The invention also relates to a method for manufacturing a rotor. In this case, the permanent magnets are fixed, in particular glued, to the bearing area of ​​at least one of the two end sides of the carrier. The ends of the bandages are then passed through the through-holes and connected, in particular thermally connected, while forming an axial binding. The invention also relates to an axial-flow motor having at least one stator and at least one rotor according to the invention, the at least one stator and the at least one rotor being arranged adjacent to each other in the axial direction while forming at least one air gap. The motor vehicle according to the invention comprises at least one axial-flow motor according to the invention. The motor vehicle is in particular an electrified motor vehicle and has the at least one axial-flow motor as a drive motor.

[0008] The rotor has the carrier, which is designed to guide the rotor flux excited by the permanent magnets of the rotor and the stator flux excited by the magnetic field generating components of the at least one stator, especially the stator winding. For this purpose, the carrier can have a magnetically conductive material, such as iron. The carrier can have a solid material or a laminated stack. The carrier is especially configured in the shape of an annular disk and has a circular outer edge and a circular inner edge. The carrier is connected to the rotor shaft extending axially along the rotation axis of the rotor through the inner edge in a rotationally fixed manner. The rotor has a plurality of rotor poles, which are arranged around the rotation axis with alternating polarities in the circumferential direction. Here, each rotor pole is especially equipped with a sector of the carrier. The radially oriented edges of a sector correspond to the pole edges of the corresponding rotor pole. The carrier has an annular end side or end side surface opposite in the axial direction, and at least one end side of the two end sides faces the stator. In the case where the axial flow motor has only one stator, only one end side of the two end sides of the rotor faces the stator. In the case of an axial-flow electric machine having two stators, the rotor is arranged between the two stators, with the two end sides facing each stator.

[0009] A plurality of permanent magnets are fixed on at least one end side of the carrier facing the stator. The permanent magnets are especially configured in the shape of ring segments or cake pieces and are arranged in a ring shape around the rotor axis in the circumferential direction. In particular, a single-piece permanent magnet or a multi-piece segmented permanent magnet in the circumferential direction is arranged in each sector on at least one end side of the carrier. In the case where the rotor is equipped on one side, each rotor pole is equipped with a permanent magnet. In the case where the rotor is equipped on both sides, each rotor pole is equipped with two permanent magnets that are opposite in the axial direction. Each permanent magnet is configured as a surface magnet, the lower side of which is in contact with the carrier in the corresponding bearing area and is fixed to the carrier. The connection between the permanent magnet and the carrier is especially a material-locked connection, such as bonding. The upper side of each permanent magnet is adjacent to the air gap formed between the stator and the rotor.

[0010] The bearing area or the resting surface for the permanent magnet extends in the radial direction between the inner area of ​​the annular end side adjacent to the inner edge and the outer area of ​​the carrier that is radially outside and adjacent to the outer edge. Preferably, the carrier has a greater axial thickness in the inner area of ​​the carrier and in the outer area of ​​the carrier than in the bearing area, so that the carrier has an annular recess on at least one end side. The annular recess has a bearing area for the permanent magnet. The inner area and the outer area of ​​the carrier that protrude axially relative to the bearing area constitute an annular ring bank-shaped radial delimitation for the permanent magnet, and the radial movement of the permanent magnet can be prevented by the radial delimitation. For this purpose, the permanent magnet is abutted against the inner side of the radially inner sector of the carrier, and is abutted against the outer area of ​​the carrier with the outer side of the radially outer sector. The upper side of the outer area and the upper side of the permanent magnet are arranged in an aligned manner with each other here, so that the permanent magnet does not extend beyond the outer area in the axial direction, that is, it does not exceed on the carrier. In the case of a carrier equipped on both sides, the inner region and the outer region can extend axially in both directions, so that the carrier is, for example, at least partially configured in the form of an H-profile. In the case of a carrier equipped on one side, the inner region and the outer region can extend axially only in one direction toward the stator, so that the carrier is, for example, at least partially configured in the form of a U-profile.

[0011] In this case, the at least one permanent magnet of each rotor pole is additionally fixed to the carrier by means of a bandage. The bandage forms an annular axial binding, which surrounds the carrier in the support region and the at least one permanent magnet arranged axially on the support region. The at least one permanent magnet of each rotor pole is thus firmly bound to the carrier by means of the bandage, in that the permanent magnet and the support region are surrounded or wrapped by the bandage in the axial direction and on the end side while forming the axial binding. The bandage comprises, in particular, a glass fiber material or a carbon fiber reinforced plastic (CFRP). These materials can be thermally connected, for example welded, to close the bandage.

[0012] In order to penetrate the carrier, the carrier has a plurality of penetrations distributed in the circumferential direction. For example, each rotor pole can be equipped with two penetrations spaced apart in the circumferential direction, partially extending through the carrier in the radial direction and completely extending in the axial direction, and the at least one permanent magnet of the rotor pole is arranged between the penetrations. Here, each penetration is arranged in the region of each pole edge, and in particular adjacent to the corresponding bearing area. The ends of each bandage are inserted through the penetration and connected, for example welded, at the end side. Therefore, each bandage has two first sections extending in the axial direction and two second sections extending tangentially on the end side. Here, each first section is arranged in the axial penetration or opening of the carrier and on the side area of ​​the permanent magnet. At least one second section extends on the upper side of the permanent magnet. In the case where only one end side is equipped with a permanent magnet, a second section extends on the unequipped end side of the carrier. As a result, each bandage extends locally in the axial direction and thus absorbs axial forces, which act on the permanent magnets during operation of the axial-flow motor and by which the permanent magnets can be lifted locally in the axial direction from the carrier. As a result, the permanent magnets are particularly securely fixed to the carrier and the axial-flow motor is advantageously also suitable for high rotational speeds.

[0013] Preferably, the bandage is only arranged in a first sub-region of the bearing area of ​​the rotor, which is adjacent to the inner region and is radially spaced apart from the outer region. The second sub-region extends radially between the first sub-region and the outer region and is configured without a bandage. The bandage therefore only partially covers the upper side of the permanent magnet in the radial direction. Therefore, only those sections of the permanent magnets that are at risk of loosening are fixed to the carrier by means of the bandage. These sections at risk of loosening are in particular radially inner sections of the ring-segment-shaped permanent magnets, which may loosen from the carrier when the rotor rotates and may be lifted axially in the direction of the stator.

[0014] It can be provided that the permanent magnets have a constant axial thickness in the radial direction, so that the rotor has a greater axial length in the first subregion provided with the bandage arrangement than in the second subregion. Due to the constant thickness of the permanent magnets in the radial direction, the rotor has a constant magnetic flux in the radial direction. However, the bandage extending over the respective permanent magnets locally increases the axial length of the rotor and thus ensures an air gap that varies in the radial direction.

[0015] Alternatively, the permanent magnets have a variable axial thickness in the radial direction, so that the rotor has approximately the same axial length in the first sub-region provided with the bandage device and in the second sub-region without the bandage. Here, the air gap is constant in the radial direction, while the magnetic flux is not constant. In order to provide a variable thickness of the permanent magnets, these permanent magnets can have a step at the transition between the first sub-region provided with the bandage and the second sub-region, the permanent magnets having a constant first thickness in the first sub-region and a constant second thickness greater than the first thickness in the second sub-region. Here, the height of the step is approximately equal to the thickness of the bandage, so that the bandage arranged in the permanent magnet section of the first sub-region is aligned with the permanent magnet section in the second sub-region. Alternatively, the permanent magnets can be wedge-shaped and have a thickness that increases continuously in the radial direction.

[0016] The perforations can be designed as radially oriented slots in the carrier, oriented parallel to the pole edges, so that the curved edges of the bandage are oriented radially and extend parallel to the side surfaces of the permanent magnets. In a top view toward the end side of the rotor, each bandage has a trapezoidal shape, wherein the curved edges of the bandage are oriented obliquely to each other. The width of the slot is only slightly greater than the thickness of the bandage, so that the slot causes as little material loss as possible on the carrier. A carrier designed in this way is particularly stable.

[0017] Instead, the through-portion is designed as a cavity, the inner wall of which adjoins the bearing area and is parallel to the axis extending in the pole center, so that the curved edges of the bandage are oriented parallel to each other and to the axis extending in the pole center. The cavity forms a larger opening for the bandage than the slot, so that the end of the bandage can be passed through the carrier more easily and the bandage device can be manufactured more easily. For example, a cavity can extend over two rotor poles, so that two adjacent rotor poles are assigned a cavity in each case. In a top view toward the end side of the rotor, each bandage has a rectangular shape here. With the help of this solution, the carrier and therefore the rotor have a particularly low weight.

[0018] The embodiments described with reference to the rotor according to the invention and their advantages apply correspondingly to the method according to the invention, the axial flow machine according to the invention and the motor vehicle according to the invention.

[0019] Further features and advantages are derived from the claims, the drawings and the description of the drawings. Features and feature combinations mentioned above in the description and features and feature combinations mentioned below in the description of the drawings and / or shown individually in the drawings can be used not only in the respectively specified combination but also in other combinations or individually. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will now be explained in more detail with the aid of preferred embodiments and with reference to the accompanying drawings. The accompanying drawings are as follows:

[0021] Figures 1a to 1d Different views of a sector of the rotor shown in the first solution;

[0022] Figure 2a to 2d Different views of one sector of the rotor shown in the second solution;

[0023] Figure 3a to 3d different views of a sector of a rotor shown in a third embodiment; and

[0024] Figures 4a to 4d Different views of a sector of a rotor shown in a fourth embodiment;

[0025] In the figures, identical elements or elements having the same function are provided with the same reference symbols. DETAILED DESCRIPTION

[0026] Figure 1a , 1b , 1c and 1d, Figure 2a , 2b , 2c and 2d, Figure 3a , 3b , 3c and 3d and Figure 4a , 4b 4c and 4d show different schemes of the rotor 1 for an axial flow motor from different viewing angles. Figure 1a , 2a , 3a, 4a respectively show perspective views of the rotor poles of the rotor 1, Figure 1b , 2b , 3b, 4b show a top view of the rotor poles of the rotor 1, Figure 1c , 2c , 3c, 4c show a cross-sectional view of the corresponding rotor pole along the section line AA passing through the pole center, and Figure 1d , 2d , 3d, 4d show side views of the rotor poles toward the pole edge.

[0027] The rotor 1 has a carrier 2, which is formed in an annular disk shape. Each rotor pole is provided with a sector 3 of the annular disk-shaped carrier 2. The carrier 2 has two end sides 4, 5 opposite to each other in the axial direction. On at least one of the two end sides 4, 5, only on the end side 4, a permanent magnet assembly with a plurality of permanent magnets 6 is provided. The end side 4 equipped with the permanent magnet 6 faces an axially adjacent stator of the axial flow motor which is not shown here. Here, a segmental permanent magnet 6 is provided for each rotor pole, which is segmented along the circumferential direction U and thus includes a plurality of sub-segments 6a of the same polarity. By segmenting the permanent magnet 6, eddy current losses are reduced. The end side 7 has a plurality of bearing areas 7 for a plurality of permanent magnets 6, which are bounded in the radial direction R by the inner area 8 and the outer area 9 of the carrier 2. The inner area 8 and the outer area 9 are formed protrudingly relative to the middle area in the axial direction. The middle area forms an annular recess 10, on the flat surface of which the bearing area 7 is provided. In this case, the inner region 8 is of double-stepped design, wherein the inner region 8 forms a contact surface on an inner edge 11 of the carrier 2 for a rotor shaft (not shown here) which is connected to the carrier 2 in a rotationally fixed manner.

[0028] The permanent magnet 6 here rests on the corresponding support area 7 with its lower side 12. The upper side 13, which is axially opposite to the lower side 12, faces the air gap between the rotor 1 and the stator. There may be an adhesive layer between the lower side 12 and the support area 7, by which the permanent magnet 6 is connected to the carrier 2 in a material-locked manner. In addition to the adhesive layer, the permanent magnet 6 is fixed to the carrier 2 by a bandage 14. The bandage 14 serves as a fixing member, by which the permanent magnet 6 is strapped to the carrier 2. In the strapped state, the bandage 14 is closed in an annular shape and straps the permanent magnet 6 and the associated support area 7. The bandage 14 is arranged in a first sub-region 15 of the carrier 2 adjacent to the inner region 8 and extends axially through the carrier 2, as well as on the upper side 13 of the permanent magnet 6 and on the end side 5 of the carrier 2. During the operation of the rotor 1, it may occur that the second sub-region 16 adjacent to the first sub-region 15 is bent away from the stator in the axial direction. In order to prevent the permanent magnet 6 from being displaced in the axial direction in the first subregion 15 and from becoming detached from the carrier 2 , the bandage 14 is arranged in the first subregion 15 .

[0029] In order to be able to pass the bandage 14 through the carrier 2, the carrier has a plurality of axial openings 17, which are arranged in the region of the respective pole edges. Figures 1a to 1d, 2a to 2d and 3a to 3d are designed as radially oriented slots 18. In this case, each rotor pole and therefore each sector 3 of the carrier 2 has two slots 18, which are arranged spaced apart from each other in the circumferential direction and between which the permanent magnet 6 is arranged. Therefore, the slots 18 are oriented parallel to the side surfaces of the permanent magnet 6. Therefore, the curved edges 19 of the bandage 14 are oriented in the radial direction, which form the transition of the bandage 14 from the side surface of the permanent magnet 6 to the surface 13 or the transition to the end side 5 via the slot. According to Figures 4a to 4d In the embodiment shown in FIG. 1 , the through-hole 17 is designed as a cavity 20, wherein the wall of the cavity 20 facing the permanent magnet 6 and thus the curved edge 19 of the bandage 14 is designed parallel to the axis extending through the pole center. Here, the cavity 20 is designed as a tangential constriction of the sector 3, in which the edge of the sector 3 has a cutout 21 extending in the direction of the pole center.

[0030] In press Figures 1a to 1d In the embodiments 4a to 4d, the permanent magnet 6 (especially see Figure 1c ) has a constant axial thickness D in the radial direction R. Therefore, the rotor 1 has a first length L1 in the first sub-region 15 due to the bandage 14 extending over the permanent magnet 6, which is greater than in the second sub-region 16 without bandage (see Figure 1d ) The second length L2 in the rotor 1 is thus not constant along the radial direction R.

[0031] In press Figure 2a to 2d In the embodiment of the rotor, the permanent magnet 6 (especially see Figure 2c ) has a first thickness D1 in the first subregion 15 and a second, greater thickness D2 in the second subregion 16 in the radial direction R. A step 22 is formed at the transition between the first subregion 15 and the second subregion 16, the height of which is equal to the thickness of the bandage 14. Thus, the axial length L of the rotor 1 is constant along the radial direction R in the subregions 15, 16.

[0032] In press Figure 3a to 3d In the embodiment of the rotor 1, the permanent magnet 6 (especially see Figure 3c ) has a varying thickness d(R) in the radial direction R. The thickness d(R) increases linearly outward in the radial direction R. Therefore, the axial length L of the rotor 1 along the radial direction R is also substantially constant.

Claims

1. A rotor (1) for an axial flow motor, the rotor comprising: - a permanent magnet assembly for generating magnetic flux, the permanent magnet assembly having a plurality of permanent magnets (6); - a carrier (2) having two axially opposite end sides (4, 5), at least one of the two end sides (4, 5) having a plurality of bearing areas (7) on which the permanent magnets (6) of the permanent magnet assembly are fixed; and - a bandage device for receiving the force acting on the permanent magnet (6); It is characterized in that The bandage device has a plurality of bandages (14), which extend axially through the carrier (2) and extend on the end side onto the permanent magnet (6), and are used to fix the permanent magnet (6) on an associated support area (7) and to receive forces acting axially on the permanent magnet (6), and the carrier (2) has a plurality of axial through-holes (17) for this purpose, through which the bandages (14) pass and in the process bundle the permanent magnet (6) and the support area (7).

2. The rotor (1) according to claim 1, characterized in that The permanent magnet (6) is additionally fixed to the support region (7) in a materially bonded manner, in particular adhesively bonded.

3. The rotor (1) according to claim 1 or 2, characterized in that The carrier (2) is designed in the form of an annular disk and has a radially inner inner region (8) and a radially outer outer region (9), the inner region facing a central opening for the rotor shaft, the carrier region (7) extending radially between the inner region (8) and the outer region (9); - the permanent magnet (6) is in the form of a ring segment, the rotor (1) has a plurality of rotor poles of alternating polarity adjacent to each other in the circumferential direction (U), and each rotor pole is provided with a sector (3) of a ring-disk-shaped carrier (2), at least one ring-segment-shaped permanent magnet (2), two axial penetrations (17) and a bandage (14).

4. The rotor (1) according to claim 3, characterized in that The bandage (14) is arranged only in a first subregion (15) of the support region (7) of the rotor equipped with permanent magnets (6), which first subregion adjoins the inner region (8) and is radially spaced apart from the outer region (9).

5. The rotor (1) according to claim 3 or 4, characterized in that The carrier (2) has a greater axial thickness in the inner region (8) and in the outer region (9) than in the bearing region (7), so that the carrier (2) has an annular recess (10) between the inner region (8) and the outer region (9) on at least one end side (4), the annular recess (10) having the bearing region (7) for the permanent magnet (6).

6. The rotor (1) according to claim 4 or 5, characterized in that The permanent magnet (6) has a constant axial thickness (D) along the radial direction (R), so that the rotor (1) has a first axial length (L1) in a first sub-region (15) provided with a bandage device and has a second axial length (L2) that is smaller than the first axial length (L1) in a second sub-region (16) of the bearing region (7) adjacent to the first sub-region (15) and the outer region (9).

7. The rotor (1) according to claim 4 or 5, characterized in that The permanent magnet (6) has a varying axial thickness (d(R), D1, D2) along the radial direction (R), so that the rotor (1) has approximately the same axial length (L) in a first sub-region (15) provided with a bandage device and in a second sub-region (16) of the support region (7) adjacent to the first sub-region (15) and the outer region (9).

8. The rotor (1) according to claim 7, characterized in that The permanent magnet (6) has a step (22) at the transition between a first sub-region (15) provided with a bandage and a second sub-region (16) without a bandage, the permanent magnet (6) having a constant first thickness (D1) in the first sub-region (15) and a constant second thickness (D2) in the second sub-region (16) which is greater than the first thickness (D1).

9. The rotor (1) according to claim 7, characterized in that The permanent magnet (6) is designed in a wedge-shaped manner and has a thickness (d(R)) which increases continuously in the radial direction (R).

10. A rotor (1) according to any one of the preceding claims, characterised in that The aperture (17) is designed as a radially oriented slot (18) in the carrier (2), so that the bent edge (19) of the bandage (14) is oriented parallel to the radially oriented side surface of the permanent magnet (6).

11. A rotor (1) according to any one of claims 1 to 9, characterised in that The aperture (17) is designed as a cavity (20), the inner wall of which adjoins the support region (7) and is parallel to an axis extending in the extreme center, so that the bending edges (19) of the bandage (14) are oriented parallel to one another and to the axis extending in the extreme center.

12. A rotor (1) according to any one of the preceding claims, characterised in that The ends of the bandage (14) are thermally connected in the connection region to form a corresponding closed axial bundle.

13. A method for manufacturing a rotor (1) according to any one of the preceding claims, the method comprising the steps of: - fixing the permanent magnets in the support region of at least one of the two end sides of the carrier; - passing the ends of each bandage through the through-hole; The ends of the bandages are connected, forming an axial bundle for the permanent magnets (6) and the support area (7).

14. An axial-flow electric machine comprising at least one stator and at least one rotor (1) according to any one of the preceding claims, the at least one stator and the at least one rotor (1) being arranged adjacent to one another in the axial direction.

15. A motor vehicle comprising at least one axial flow electric machine according to claim 14.

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