Motor rotor, motor, electric drive assembly system and vehicle

Abstract

The invention relates to a motor rotor. The motor rotor comprises a rotor lamination assembly; the motor shaft can rotate around a rotation axis and is rotationally fixed with the rotor lamination assembly, the motor shaft comprises a first end and a second end which extend out of the rotor lamination assembly, and the second end is opposite to the first end; and a fastening assembly fixed to the motor shaft at at least one of the first end and the second end and pressed against the rotor lamination assembly. The motor shaft comprises a center hole and a first communication hole communicated with the center hole, the fastening assembly comprises a second communication hole communicated with the outer surface of the fastening assembly, and a containing space communicated with the first communication hole and the second communication hole and used for cooling fluid is formed in the interface area of the motor shaft and the fastening assembly. The disclosure also relates to an electric machine, an electric drive assembly system and a vehicle.

Description

Technical Field

[0001] The present disclosure relates to an electric motor rotor. The present disclosure also relates to an electric motor including such an electric motor rotor, an electric drive assembly system including the electric motor, and a vehicle including the electric drive assembly system. Background Art

[0002] An electric motor for driving a vehicle generally has a relatively large power and generates a large amount of heat during continuous operation. If the heat dissipation is insufficient, the generated heat will accumulate inside the electric motor, causing the temperature of the electric motor to rise and affecting the reliability and performance of the electric motor. An oil-cooled electric motor can directly contact the cooling medium (cooling fluid) with the internal components of the electric motor, so it has a better cooling effect and has been more and more widely used in the field of vehicles. In an oil-cooled electric motor, the cooling fluid is usually introduced at the motor shaft of the electric motor rotor, and the centrifugal force generated when the electric motor rotor rotates is used to spray the cooling fluid toward the radial outside to cool the various components of the electric motor.

[0003] The winding of the stator is a main heat-generating component of the electric motor, and it generally includes winding ends extending beyond the stator body at both axial ends of the electric motor. Therefore, it is desirable that the cooling fluid entering the motor shaft of the rotor can be directly sprayed onto the winding ends of the stator at both axial ends of the electric motor to cool the windings.

[0004] An electric motor rotor generally includes a plurality of laminations tightly stacked together, and these laminations are pressed by fasteners provided at both of their axial ends, so that the laminations remain tightly arranged when the electric motor rotates at a high speed. The fasteners pose an obstacle to spraying the cooling fluid from the motor shaft of the rotor toward the winding ends of the stator. In order to avoid the fasteners, the common practice is to spray the cooling fluid toward the winding ends on the axial outer side of the fasteners.

[0005] However, in order to increase the power density of the electric motor, the axial length of the winding extending beyond the stator body is compressed, that is, the winding ends are shortened. This results in that the cooling fluid sprayed on the axial outer side of the fasteners can only spray to the outermost ends of the winding ends, or even cannot spray onto the winding ends at all, causing the cooling effect of the electric motor to decline. Summary of the Invention

[0006] Therefore, the present disclosure aims to solve the above problems existing in the conventional electric motor rotor, and its purpose is to provide an electric motor rotor, in which the cooling fluid can be sprayed at a position axially close to the rotor laminations, so that even when the winding ends are shortened, the cooling fluid can be reliably sprayed onto the winding ends to sufficiently cool the stator windings of the electric motor.

[0007] The above object is achieved by a motor rotor according to an embodiment of the present disclosure, which includes: a rotor lamination assembly; a motor shaft capable of rotating about a rotation axis and rotationally fixed to the rotor lamination assembly, the motor shaft including a first end and a second end extending beyond the rotor lamination assembly, the second end being opposite to the first end; a fastening assembly fixed to the motor shaft at at least one of the first end and the second end and pressing against the rotor lamination assembly. The motor shaft includes a central hole and a first communication hole communicating with the central hole, the fastening assembly includes a second communication hole communicating with the outer surface of the fastening assembly, and a receiving space for cooling fluid communicating with the first communication hole and the second communication hole is provided at the interface region between the motor shaft and the fastening assembly.

[0008] One object of the present disclosure is to provide a motor rotor capable of spraying cooling fluid at a position axially close to the rotor lamination. According to the motor rotor of the present disclosure, it includes a central hole provided on the motor shaft, a first communication hole communicating with the central hole, a receiving space provided at the interface region between the motor shaft and the fastening assembly, and a second communication hole provided on the fastening assembly and communicating with the outer surface of the fastening assembly. Thus, the cooling fluid can pass through the fastening assembly from the central hole of the motor shaft through the first communication hole, the receiving space and the second communication hole, and is sprayed towards the winding end of the stator under the action of centrifugal force. That is to say, the motor rotor can spray the cooling fluid through the fastening assembly, so as to be able to spray the cooling fluid at a position axially close to the rotor lamination. In this way, even if the winding end is shortened, the motor rotor can reliably spray the cooling fluid on the winding end to sufficiently cool the stator winding of the motor.

[0009] The motor rotor according to the present disclosure may also have one or more of the following features individually or in combination.

[0010] According to an embodiment of the present disclosure, the receiving space is a groove. The groove is, for example, a circumferential groove. Preferably, the circumferential groove surrounds the entire circumference of the interface region.

[0011] According to an embodiment of the present disclosure, the groove is provided on the outer surface of the motor shaft; or the groove is provided on the inner surface of the fastening assembly.

[0012] According to an embodiment of the present disclosure, the groove includes a first groove portion provided on the outer surface of the motor shaft and a second groove portion provided on the inner surface of the fastening assembly. Exemplarily, the groove is formed by the cooperation of the aligned first groove portion and the second groove portion.

[0013] According to an embodiment of the present disclosure, the fastening assembly includes a nut screwed onto the motor shaft.

[0014] According to an embodiment of the present disclosure, the nut includes a first section provided with threads and a second section closer to the rotor lamination assembly, and the groove is provided at the interface region between the second section and the motor shaft.

[0015] According to an embodiment of the present disclosure, the fastening assembly includes a gasket disposed between the nut and the rotor lamination assembly.

[0016] According to an embodiment of the present disclosure, the fastening assembly includes an end plate disposed between the gasket and the rotor lamination assembly.

[0017] According to an embodiment of the present disclosure, the groove is provided at the interface region between the gasket or the end plate and the motor shaft.

[0018] According to an embodiment of the present disclosure, the motor shaft includes a plurality of first communication holes uniformly distributed around the rotation axis, and / or the fastening assembly includes a plurality of second communication holes uniformly distributed around the rotation axis.

[0019] The present disclosure also relates to a motor, which includes the motor rotor as described above.

[0020] The present disclosure also relates to an electric drive assembly system, which includes the motor as described above.

[0021] The present disclosure also relates to a vehicle, which includes the electric drive assembly system as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other features and advantages of the present disclosure will become more apparent from the following detailed description of exemplary embodiments in conjunction with the accompanying drawings, and the description and drawings are for exemplary purposes only and do not limit the scope of the present disclosure in any way. The following drawings are not deliberately drawn to scale in actual size, and the focus is on showing the gist of the present disclosure.

[0023] Figure 1 is a side view of a motor rotor according to the present disclosure.

[0024] Figure 2 is a schematic cross-sectional view of a motor according to the present disclosure.

[0025] Figure 3 shows the motor shaft of a motor rotor according to the present disclosure.

[0026] Figure 4 shows the nut of a motor rotor according to the present disclosure. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure.

[0028] Unless otherwise defined, technical terms or scientific terms used herein shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present disclosure pertains. The words such as "a", "an", or "the" used in the specification and claims of the patent application of the present disclosure do not indicate a limitation in quantity, but rather indicate the existence of at least one. Words such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents. "Connection" or "coupling" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative position relationships, and when the absolute position of the object being described changes, the relative position relationship may also change accordingly. The terms "axial" and "axial direction" refer to the direction of the rotation axis X of the motor rotor, "radial" and "radial direction" refer to the direction perpendicular to the rotation axis X, and "circumferential" and "circumferential direction" refer to the circumferential direction around the rotation axis X.

[0029] For the convenience of description, the accompanying drawings of the present disclosure correspondingly simplify or omit commonly used components in the art, such as other components unrelated to the description of the present disclosure, such as external connection lines. These omitted or simplified components do not affect those skilled in the art's understanding of the content of the present disclosure.

[0030] Figure 1 A motor rotor 100 according to an exemplary embodiment of the present disclosure is shown. Figure 2 A motor including the motor rotor 100 is shown in a sectional view.

[0031] As Figure 1 and Figure 2 shown, the motor includes a motor rotor 100 and a motor stator 200. The motor rotor 100 includes a rotor lamination assembly 10 and a motor shaft 20. The motor shaft 20 passes through the center of the rotor lamination assembly 10 and is rotationally fixed to the rotor lamination assembly 10, and they rotate together around the rotation axis X. The motor shaft 20 includes a first end 20a extending beyond the rotor lamination assembly 20 and a second end 20b opposite to the first end 20a.

[0032] The rotor lamination assembly 20 is formed by a group of stacked rotor laminations. These rotor laminations are tightly stacked together with sufficient pressing force to ensure the stiffness and strength of the motor rotor. To ensure that the rotor laminations can be tightly held during the high-speed rotation of the motor rotor, the motor rotor 1 further includes a fastening assembly 30, which is fixed to the motor shaft 20 at the first end 20a and / or the second end 20b of the motor shaft 20 and presses against the rotor lamination assembly 10. As Figure 1 shown, the fastening assembly 30 at the second end 20b includes an end plate 33 positioned close to the rotor lamination assembly 10, a nut 31 screwed onto the motor shaft 20, and a gasket 32 disposed between the end plate 33 and the nut 31. The nut 31 presses against the end plate 33 toward the rotor lamination assembly 10 through the gasket 32, applying a pressing force that tightly stacks the rotor laminations together. It should be understood that some components in the fastening assembly 30 can be omitted, such as the end plate 33, the gasket 32, etc.

[0033] Cooling fluid circulates inside the motor to cool various parts of the motor 100. Exemplarily, the cooling fluid can be cooling oil. Referring to Figure 2 , the motor shaft 20 can be provided with a central hole 21. The cooling fluid flows into the motor shaft 20 from this central hole 21, and then is sprayed radially from the motor shaft 20 under the drive of centrifugal force and reaches various components of the motor 100 to cool them.

[0034] Among the various components of the motor 100, the stator 200 includes windings in which a large alternating current flows, for generating an alternating magnetic field that drives the rotor 100 to rotate. Therefore, the windings of the stator 200 are one of the main heat-generating components of the motor 100. As Figure 2 shown, the windings extend beyond the main body 201 of the stator 200 to form winding ends 202. When cooling the stator 200, it is preferably to directly spray the cooling fluid radially onto the winding ends 202, and then flow axially to cool the entire stator 200.

[0035] However, as Figure 2 shown, the rotor lamination assembly 10 of the motor rotor 100 and the main body 201 of the stator 200 are substantially coincident in the radial direction, and the winding ends 202 are substantially coincident with the fastening assembly 30 in the radial direction. In particular, when the axial length of the winding ends 202 is small (as Figure 2 shown), if the cooling fluid is sprayed radially outside the fastening assembly 30 of the motor rotor 100 (i.e., on the side away from the rotor lamination assembly 10), it is difficult for the cooling fluid to be sprayed onto the winding ends 202. Therefore, the motor rotor 100 needs to spray the cooling fluid through the fastening assembly 30 in order to reliably spray the cooling fluid onto the winding ends 202. For this purpose, the motor rotor 100 according to the present disclosure is provided with a passage for the cooling fluid to pass through the fastening assembly 30.

[0036] Reference Figure 1 - Figure 2 , at the second end 20b of the motor shaft 20, a receiving space for the cooling fluid is provided in the interface area between the motor shaft 20 and the fastening assembly 30, which exemplarily has the form of a groove 1. Preferably, the groove 1 is a circumferential groove surrounding the interface area. A first communication hole 22 that is in fluid communication with the central hole 21 and the groove 1 is provided on the motor shaft 20, and a second communication hole 34 that is in fluid communication with the groove 1 and its outer surface is provided on the fastening assembly 30. The cooling fluid supplied to the motor shaft 20 from the central hole 21 can be reliably sprayed onto the winding end 202 through the first communication hole 22, the groove 1, and the second communication hole 34. The second communication hole 34, the groove 1, and the first communication hole 22 form a passage for the cooling fluid to pass through the fastening assembly 30. Through the above configuration, the cooling fluid in the central hole 21 enters the groove 1 through the first communication hole 22, then flows into the second communication hole 34, and is sprayed from the second communication hole 34 toward the winding end 202 to cool it. That is to say, the flow path of the cooling fluid in the motor rotor 100 according to this embodiment is: central hole 21 → first communication hole 22 → groove 1 → second communication hole 34.

[0037] Reference Figure 2 - Figure 4 , the groove 1 is provided on the outer surface of the motor shaft 20 and is a circumferential groove that is recessed inward on the outer surface of the motor shaft 20. The axial position of the first communication hole 22 is substantially the same as that of the groove 1, and the first communication hole 22 extends radially to communicate the central hole 21 and the groove 1. The nut 31 includes a first section 31a provided with threads and a second section 31b closer to the rotor lamination assembly 10. The corresponding part of the motor shaft 20 is also provided with corresponding threads, so that the nut 31 can be screwed on the motor shaft 20 through the first section 31a. The axial position of the second section 31b corresponds to that of the groove 1, that is, the groove 1 is provided at the interface area between the second section 31b and the motor shaft 20. Correspondingly, the second communication hole 34 is also provided on the second section 31b of the nut 31, and the axial position of the second communication hole 34 is substantially the same as that of the groove 1 and extends radially to the outer surface of the nut 31. The nut 31 may also be provided with a fixing groove 35 on its outer surface, and the fixing groove 35 can cooperate with a tool to screw the nut 31. In Figure 4 the illustrated embodiment, the second communication hole 34 leads to the bottom surface of the fixing groove 35.

[0038] In an alternative embodiment not shown in the drawings, the groove 1 may also be provided on the inner surface of the fastening assembly 30 and is a circumferential groove recessed outwardly from the inner surface of the fastening assembly 30. Further optionally, the groove 1 may be partially provided on the motor shaft 20 and partially provided on the fastening assembly 30. That is, the groove 1 may be composed of a first groove portion provided on the outer surface of the motor shaft 20 and a second groove portion provided on the inner surface of the fastening assembly 30. In the axial direction, the groove 1 may be closer to the rotor lamination assembly 10, that is, the groove 1 may be provided at the interface region between the gasket 32 or the end plate 33 and the motor shaft 20. Correspondingly, the second communication hole 34 may also be provided on the gasket 32 or the end plate 33.

[0039] In addition, Figure 2 it is shown that the first communication hole 22 and the second communication hole 34 are aligned. Due to the provision of the groove 1 at the interface region between the motor shaft 20 and the fastening assembly 30, the first communication hole 22 and the second communication hole 34 may also be offset from each other. The cooling fluid may flow circumferentially in the groove 1 at a certain angle and then enter the second communication hole 34. Therefore, when installing the fastening assembly 30, it is no longer necessary to align the first communication hole 22 and the second communication hole 34, reducing the assembly difficulty of the motor rotor 100. Of course, the first communication hole 22 and the second communication hole 34 may also be offset from each other at a predetermined angle to adjust the flow resistance of the sprayed cooling fluid. The motor shaft 20 includes a plurality of first communication holes 22 (illustrated as 4) evenly distributed around the rotation axis X, and the fastening assembly 30 also includes a plurality of second communication holes 34 (illustrated as 4) evenly distributed around the rotation axis X. The numbers of the two may be the same or different. The groove 1 may be a single groove completely surrounding the interface region for one week, or may be composed of a plurality of segmented grooves, and each segmented groove may respectively communicate with a first communication hole 22 and a second communication hole 34. In addition, the first communication hole 22 and the second communication hole 34 may also extend at an angle with respect to the radial direction.

[0040] The structure of the second end 20b of the motor shaft 20 and the fastening assembly 30 located at the second end 20b of the motor shaft 20 has been described above in conjunction with the drawings. As Figure 1 - Figure 3As shown, the motor rotor 100 has a different structure at the first end 20a of the motor shaft 20. Specifically, a flange 23 is provided at the first end 20a of the motor shaft 20, and an end plate 33 is arranged between the flange 23 and the rotor lamination assembly 10. The flange 23 forms a stopper for the end plate 33 at the first end 20a, such that the rotor lamination assembly 10 is squeezed between the two end plates 33 at the first end 20a and the second end 20b. A radial hole 24 communicating with the central hole 21 is provided on the flange 23, and the cooling fluid can be directly sprayed onto the winding end 202. It can be understood that the structure of the motor rotor 100 at the first end 20a of the motor shaft 20 can also have the same structure as that at the second end 20b. That is, the fastening assembly 30 is also arranged at the first end 20a of the motor shaft 20.

[0041] According to another aspect of the present disclosure, an electric drive assembly system is proposed, which includes the motor as described above.

[0042] According to another aspect of the present disclosure, a vehicle is proposed, which includes the electric drive assembly system as described above. The vehicle can be an electrified vehicle, such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a range extended electric vehicle, a fuel cell electric vehicle (FCEV). The vehicle can also be a hydrogen energy vehicle.

[0043] Certain features, structures, or characteristics in one or more embodiments of the present disclosure can be appropriately combined.

[0044] The above is an illustration of the present disclosure and should not be considered as a limitation thereof. Although several exemplary embodiments of the present disclosure have been described, those skilled in the art will easily understand that many modifications can be made to the exemplary embodiments without departing from the novel teachings and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure defined by the claims. It should be understood that the above is an illustration of the present disclosure, and the present disclosure should not be considered limited to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the present disclosure.

Claims

1. A motor rotor (100), characterized in that, The motor rotor (100) includes: a rotor lamination assembly (10); a motor shaft (20) that is rotatable about a rotation axis (X) and is rotationally fixed to the rotor lamination assembly (20), the motor shaft (20) including a first end (20a) and a second end (20b) that extend beyond the rotor lamination assembly (20), the second end (20b) being opposite to the first end (20a); a fastening assembly (30) that is fixed to the motor shaft (20) at at least one of the first end (20a) and the second end (20b) and presses against the rotor lamination assembly (10); wherein the motor shaft (20) includes a central hole (21) and a first communication hole (22) that communicates with the central hole (21); wherein the fastening assembly (30) includes a second communication hole (34) that communicates with an outer surface of the fastening assembly (30); wherein a receiving space for a cooling fluid that communicates with the first communication hole (22) and the second communication hole (34) is provided at an interface region between the motor shaft (20) and the fastening assembly (30).

2. The motor rotor (100) according to claim 1, wherein, the receiving space is a groove (1).

3. The motor rotor (100) according to claim 2, wherein, the groove (1) is provided on an outer surface of the motor shaft (20); or the groove (1) is provided on an inner surface of the fastening assembly (30).

4. The motor rotor (100) according to claim 2, wherein, the groove (1) includes a first groove portion provided on an outer surface of the motor shaft (20) and a second groove portion provided on an inner surface of the fastening assembly (30).

5. The motor rotor (100) according to any one of claims 1 to 4, wherein, the fastening assembly (30) includes a nut (31) screwed onto the motor shaft (20).

6. The motor rotor (100) according to claim 5, wherein, the nut (31) includes a first section (31a) provided with a thread and a second section (31b) closer to the rotor lamination assembly (10), and the groove (1) is provided at an interface region between the second section (31b) and the motor shaft (20).

7. The motor rotor (100) according to claim 5, wherein, the fastening assembly (30) includes a gasket (32) disposed between the nut (31) and the rotor lamination assembly (10).

8. The motor rotor (100) according to claim 7, wherein, the fastening assembly (30) includes an end plate (33) disposed between the gasket (32) and the rotor lamination assembly (10).

9. The motor rotor (100) according to claim 8, wherein, the groove (1) is provided at an interface region between the gasket (32) or the end plate (33) and the motor shaft (20).

10. The motor rotor (100) according to any one of claims 1 to 4, wherein, The motor shaft (20) includes a plurality of first communication holes (22) evenly distributed around the rotation axis (X), and / or the fastening assembly (30) includes a plurality of second communication holes (34) evenly distributed around the rotation axis (X).

11. A motor, characterized in that, The motor includes the motor rotor (100) according to any one of claims 1 to 10.

12. An electric drive assembly system, characterized in that, The electric drive assembly system at least includes the motor according to claim 11.

13. A vehicle, characterized in that, The vehicle includes the electric drive assembly system according to claim 12.

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