Rotor, electric motor, electric drive system and vehicle

Abstract

The present disclosure relates to the technical field of electric motors. Disclosed are a rotor, an electric motor, an electric drive system and a vehicle. The rotor comprises a rotor shaft and a rotor iron core coaxially sleeved on the periphery of the rotor shaft; the rotor shaft is provided with a hollow chamber for injection of a cooling medium; a flow guide hole for radially guiding the cooling medium is provided within the rotor shaft; an axial cooling passage leading to the flow guide hole is provided at the position of the rotor iron core close to its outer peripheral wall; the axial cooling passage extends from the middle of the rotor iron core to two axial ends of the rotor iron core. By means of such structure, the cooling medium flows closer to a heat source within the rotor iron core, so as to better cool the rotor. Under the same amount of heat generated, the present invention can achieve lower rotor temperatures, so as to improve electric motor efficiency and electric motor reliability. In addition, at the same rotor temperature, the present invention can take away more heat, thereby improving the continuous torque and power of electric motors.

Description

Rotors, motors, electric drive systems and vehicles

[0001] Cross-reference to related applications

[0002] This disclosure is based on and claims priority to Chinese Patent Application No. 202510202668.2, filed on February 21, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure belongs to the field of electric motor technology, and specifically relates to a rotor, an electric motor, an electric drive system, and a vehicle. Background Technology

[0004] Asynchronous motors have advantages such as low cost, high reliability, and low drag loss, and are widely used as auxiliary drive motors in the drive systems of new energy vehicles. Currently used asynchronous motor rotors are mostly of a "squirrel cage" structure, which consists of guide bars and end rings. The guide bars and end rings can be made of aluminum or copper, and can be manufactured by casting or by welding prefabricated bar-shaped rods and end rings.

[0005] When an asynchronous motor is running, current is induced in the rotor bars and end rings, generating a magnetic field that produces torque. Simultaneously, the current in the rotor bars also generates ohmic losses. Because the rotor bars are located inside the rotor core, heat dissipation is poor, and these losses cause the rotor temperature to rise. Excessive rotor temperature rise limits the motor's continuous power output. Theory and experiments show that the temperature near the outer diameter of the rotor core, close to the air gap, is affected by the heat generated by both the stator and rotor, making it one of the hottest areas in the entire motor.

[0006] To reduce rotor temperature, axial cooling channels are typically created at the bottom of the rotor core. To avoid affecting the magnetic circuit, these cooling channels are usually located close to the rotor's inner bore and relatively far from the rotor bars. While this method provides some cooling, the distance between the cooling medium and the bars (heat source) limits the cooling effect and restricts further increases in the continuous power of the asynchronous motor. Summary of the Invention

[0007] The purpose of this disclosure is to provide a rotor, motor, electric drive system, and vehicle to solve the technical problem that the cooling medium cannot effectively cool the rotor bars of an asynchronous motor, thereby limiting the further improvement of the continuous power of the asynchronous motor.

[0008] To achieve the above objectives, this disclosure provides a rotor, the rotor comprising:

[0009] The rotor shaft has a hollow cavity for injecting a cooling medium, and the rotor shaft has a guide hole for guiding the cooling medium radially.

[0010] The rotor core is coaxially disposed on the outer periphery of the rotor shaft. An axial cooling channel communicating with the guide hole is provided near the outer peripheral wall of the rotor core. The axial cooling channel extends from the middle of the rotor core to both axial ends of the rotor core.

[0011] In some embodiments, a flow-guiding cooling channel is further provided in the middle of the rotor core, with one end of the flow-guiding cooling channel communicating with the flow-guiding hole and the other end communicating with the axial cooling channel.

[0012] In some embodiments, the rotor core includes an intermediate section and end sections connected to both axial sides of the intermediate section. The cooling channel is formed on the intermediate section, and the end sections are each provided with the axial cooling channel. The axial cooling channels of the two end sections extend in opposite directions.

[0013] In some embodiments, the intermediate section is formed by stacking multiple first rotor laminations in sequence. Multiple first flow channel holes and first guide bar grooves are evenly spaced along the circumference of the first rotor laminations. The first flow channel holes are located between two first guide bar grooves. The multiple first flow channel holes on each first rotor lamination are connected one-to-one to form a flow guiding cooling channel.

[0014] In some embodiments, the cooling channel includes an axial section and a radial section that are interconnected, the axial section being located between the first guide groove and the outer peripheral wall of the intermediate section, and the radial section extending from the axial section to the middle of the intermediate section.

[0015] In some embodiments, a connecting channel is formed between the outer peripheral wall of the rotor shaft and the inner peripheral wall of the first rotor lamination, with one side of the connecting channel connecting to the guide hole and the other side connecting to the radial section.

[0016] In some embodiments, at least one of the first guide bar grooves is provided between any two adjacent flow cooling channels.

[0017] In some embodiments, the end segment is formed by stacking multiple second rotor laminations in sequence. Multiple second flow channel holes and second guide grooves are evenly spaced along the circumference of the second rotor laminations. The second guide grooves extend radially. The second flow channel holes are opened corresponding to the second guide grooves and are located between the second guide grooves and the inner circumferential wall of the end segment. The multiple second flow channel holes on each second rotor lamination are connected one-to-one to form the axial cooling channel.

[0018] A second aspect of this disclosure provides an electric motor including a rotor as described above.

[0019] A third aspect of this disclosure provides an electric drive system including the motor described above.

[0020] This disclosure provides a fourth aspect of a vehicle including the electric drive system described above.

[0021] Through the above technical solutions, the rotor provided by the embodiments of the present invention has the following beneficial effects:

[0022] The above technical solution describes a rotor comprising a rotor shaft and a rotor core coaxially sleeved around the outer periphery of the rotor shaft. The rotor shaft has a hollow cavity for injecting cooling medium, and guide holes are provided within the rotor shaft to guide the cooling medium radially. An axial cooling channel, communicating with the guide holes, is located near the outer peripheral wall of the rotor core, extending from the middle of the rotor core to both axial ends. The cooling medium injected into the hollow cavity flows through the guide holes into the axial cooling channel of the rotor core, and then flows along the axial cooling channel near the outer peripheral wall to both ends of the rotor core, ultimately being sprayed onto both ends of the rotor core. With this structure, because the axial cooling channel is located close to the outer peripheral wall of the rotor core and relatively close to the rotor bars, the flow of the cooling medium within the rotor core is closer to the heat source, resulting in better rotor cooling. Under the same heat output, this invention can lower the rotor temperature, thereby improving motor efficiency and reliability. Furthermore, at the same rotor temperature, this invention can remove more heat, thereby increasing the continuous torque and power of the motor.

[0023] Other features and advantages of the embodiments disclosed herein will be described in detail in the following detailed description section. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the following detailed description to explain the embodiments of this disclosure, but do not constitute a limitation thereof. Those skilled in the art can obtain other drawings based on the structures shown in these drawings without any inventive effort. In the drawings:

[0025] Figure 1 is a schematic diagram of the rotor according to the present disclosure;

[0026] Figure 2 is a schematic cross-sectional view of the rotor according to the present disclosure;

[0027] Figure 3 is a schematic diagram of the structure of the second rotor lamination in the first embodiment;

[0028] Figure 4 is a schematic diagram of the structure of the second rotor lamination in the second embodiment;

[0029] Figure 5 is a schematic diagram of the structure of the first rotor lamination in the third embodiment;

[0030] Figure 6 is a schematic diagram of the structure of the first rotor lamination in the fourth embodiment;

[0031] Figure 7 is a cross-sectional view of the first rotor lamination and rotor shaft after assembly in the fourth embodiment.

[0032] Figure 8 is a schematic diagram showing the relationship between the first guide bar groove and the cooling channel in the first rotor lamination;

[0033] Figure 9 is a schematic diagram showing the relationship between the second guide bar groove and the axial cooling channel in the second rotor lamination.

[0034] Reference numerals: 10 Rotor shaft; 232 Radial section; 11 Hollow cavity; 24 Axial cooling channel; 12 Guide hole; 25 First rotor lamination; 20 Rotor core; 251 First guide bar groove; 21 Intermediate section; 26 Second rotor lamination; 22 End section; 261 Second guide bar groove; 23 Guide cooling channel; 27 Connecting channel; 231 Axial section; 30 End ring; 28 Center hole. Detailed Implementation

[0035] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0036] The rotor, motor, electric drive system, and vehicle according to this disclosure are described below with reference to the accompanying drawings.

[0037] As shown in Figures 1 and 2, this disclosure provides a rotor, which includes a rotor shaft 10 and a rotor core 20 coaxially sleeved on the outer periphery of the rotor shaft 10; the rotor shaft 10 has a hollow cavity 11 for injecting a cooling medium, and a guide hole 12 is provided in the rotor shaft 10 to guide the cooling medium radially; a guide cooling channel 23 communicating with the guide hole 12 is provided in the middle of the rotor core 20, and an axial cooling channel 24 communicating with the guide cooling channel 23 is provided near the outer peripheral wall of the rotor core 20, and the axial cooling channel 24 extends from the guide cooling channel 23 to both axial ends of the rotor core 20.

[0038] Compared to related technologies where the cooling channel is located close to the inner diameter of the rotor core 20, this disclosure, by employing the above-described structure, allows the cooling medium injected into the hollow cavity 11 to flow through the guide hole 12 into the guide cooling channel 23 in the middle of the rotor core 20, and then flow along the axial cooling channel 24 near the outer diameter to both ends of the rotor core 20, ultimately being sprayed onto both ends of the rotor core 20. The rotor core 20 of this disclosure has both guide cooling channels 23 and axial cooling channels 24. By allowing the cooling medium to flow from the inside of the rotor core 20 to the outer peripheral wall, the cooling medium is brought closer to the heat source of the conductor bars on the outer diameter of the rotor core 20, resulting in better rotor cooling. Under the same heat generation, this invention can lower the rotor temperature, thereby improving motor efficiency and reliability. Furthermore, at the same rotor temperature, this invention can remove more heat, thereby increasing the continuous torque and power of the motor. For the same continuous torque and power requirements, this invention can make the motor smaller and lighter.

[0039] The cooling medium can be either transmission fluid or gas.

[0040] In some embodiments, the rotor core 20 includes an intermediate section 21 and end sections 22 connected to the two axial sides of the intermediate section 21. A cooling channel 23 is provided on the intermediate section 21, and each end section 22 is provided with an axial cooling channel 24. The axial cooling channels 24 of the two end sections extend in opposite directions.

[0041] As shown in Figure 2, the two end sections 22 extend from both ends of the middle section 21, which is located in the middle of the entire rotor core 20. The axial height of the middle section 21 is relatively small. The two end sections 22 are arranged symmetrically about the middle section 21. As can be seen from Figure 2, the cooling medium entering the hollow cavity 11 flows in the direction of the arrow. The cooling medium entering the guiding cooling channel 23 of the middle section 21 enters the outer periphery of the middle section 21 along the guiding cooling channel 23, and then flows to both ends of the axial direction along the axial cooling channels 24 of the left and right end sections 22, respectively, to cool the heat source on the outer diameter of the rotor core 20.

[0042] In some embodiments, as shown in Figures 3, 4, and 9, the end section 22 is formed by stacking multiple second rotor laminations 26 sequentially. Multiple second flow channel holes and second guide bar grooves 261 are evenly spaced circumferentially on each second rotor lamination 26. The second guide bar grooves 261 extend radially, and the second flow channel holes are corresponding to the second guide bar grooves 261 and located between the second guide bar grooves 261 and the inner peripheral wall of the end section 22. The multiple second flow channel holes on each second rotor lamination 26 are connected one-to-one to form an axial cooling channel 24. The axial cooling channel 24 is located near the outer peripheral wall of the end section 22, close to the heat source (guide bar), thereby improving the cooling effect on the rotor core 20.

[0043] The distance between any two adjacent second guide grooves 261 can be set according to actual needs and is not limited here. The inner diameter of the axial cooling channel 24 is also not limited, as long as it is located between the end of the second guide groove 261 and the inner peripheral wall of the end section 22.

[0044] There are multiple axial cooling channels 24, and the arrangement of these multiple axial cooling channels 24 can be varied, as shown in Figures 3 and 4.

[0045] As shown in Figure 3, in the first embodiment, an axial cooling channel 24 is provided at the position corresponding to the bottom of each second guide bar groove 261. That is, the number of second guide bar grooves 261 and axial cooling channels 24 are the same and correspond one-to-one. This arrangement can achieve the best cooling effect for the second rotor laminations 26.

[0046] As shown in Figure 4, in the second embodiment, the number of second guide grooves 261 and the number of axial cooling channels 24 are different; axial cooling channels 24 are only set at the positions of a few of the second guide grooves 261. In some embodiments, as shown in Figure 4, the arrangement of the multiple axial cooling channels 24 is symmetrically distributed about the center hole 28 of the rotor core 20, which can improve the cooling uniformity of the second rotor laminations 26. Of course, Figure 4 only illustrates a symmetrical arrangement, and the specific spacing between any two adjacent axial cooling channels 24 can be configured according to the number of second rotor laminations 26 and cooling requirements, and is not required to be completely evenly distributed.

[0047] In some embodiments, the intermediate section 21 is formed by stacking multiple first rotor laminations 25 sequentially. Multiple first flow channel holes and first guide grooves 251 are evenly spaced circumferentially on each first rotor lamination 25. The first guide grooves 251 extend radially, and the first flow channel holes are located between two first guide grooves 251. The multiple first flow channel holes on each first rotor lamination 25 are connected one-to-one to form a cooling channel 23. One end of the cooling channel 23 near the center is connected to the guide hole 12, and the other end extends towards the outer peripheral wall of the first rotor lamination 25, thereby achieving the purpose of guiding the cooling medium inside the rotor core 20 to the outer diameter.

[0048] The distance between any two adjacent first guide grooves 251 can be set according to actual needs and is not limited here. The inner diameter of the cooling channel 23 can also be set according to actual needs and is not limited here.

[0049] It should be noted that the stacking process of multiple second rotor laminations 26 and the stacking process of multiple first rotor laminations 25 both adopt the conventional manufacturing process of motor rotor core 20 in the prior art, which will not be described in detail here.

[0050] In some embodiments, as shown in FIG8, the cooling channel 23 includes an axial section 231 and a radial section 232 that are interconnected. The axial section 231 is located between the first guide groove 251 and the outer peripheral wall of the intermediate section 21, and the radial section 232 extends from the axial section 231 to the middle of the intermediate section 21. When the cooling medium flows, the cooling medium flowing out of the guide hole 12 first enters the radial section 232, and then flows along the radial section 232 to the axial section 231. After transitioning in the axial section 231, it flows toward the axial cooling channels 24 of the end sections 22 on the left and right sides. That is, it first enters the inner diameter of the rotor core 20, and then enters the axial section 231 (that is, the outer peripheral position of the rotor core 20) along the radial section 232, thereby realizing the change of the guiding flow direction of the cooling medium.

[0051] Furthermore, as shown in Figure 7, since the inner diameter of several of the first rotor laminations 25 is larger than the outer diameter of the rotor shaft, a connecting channel 27 is formed between the outer peripheral wall of the rotor shaft 10 and the inner peripheral wall of the first rotor laminations 25. One side of the connecting channel 27 connects to the guide holes 12, and the other side connects to the radial section 232. Without the presence of the connecting channel 27, the number of guide holes 12 on the rotor shaft 10 would need to be the same as the number of guide cooling channels 23 and correspond one-to-one. In this case, a large number of guide holes 12 would need to be drilled on the rotor shaft 10, increasing the manufacturing cost. In this embodiment, by forming the connecting channel 27, the number of guide holes 12 on the rotor shaft 10 can be reduced, further saving costs.

[0052] In some embodiments, there are multiple cooling channels 23, and the arrangement of the multiple cooling channels 23 can also be varied, as shown in Figures 5 and 6.

[0053] As shown in Figure 5, in the third embodiment, there is a first guide groove 251 between any two adjacent cooling channels 23. That is, the cooling channels 23 and the first guide grooves 251 are arranged alternately, and the number of first guide grooves 251 and cooling channels 23 are the same and correspond one-to-one. This arrangement can achieve the best cooling effect on the first rotor laminations 25.

[0054] As shown in Figure 6, in the fourth embodiment, there are multiple first guide grooves 251 between any two adjacent cooling channels 23. In this case, the number of first guide grooves 251 is different from the number of cooling channels 23; cooling channels 23 are only set at intervals between a few of the first guide grooves 251. In some embodiments, as shown in Figure 6, the arrangement of the multiple cooling channels 23 is symmetrical about the central hole 28, which can improve the cooling uniformity of the first rotor laminations 25. Of course, Figure 4 only illustrates a symmetrical arrangement, and the specific spacing between any two adjacent cooling channels 23 can be configured according to the number of first rotor laminations 25 and cooling requirements, and is not required to be completely evenly distributed.

[0055] Furthermore, the axial cooling channel 24 and the second guide bar groove 261 are not connected to each other, whether on the first rotor lamination 25 or the second rotor lamination 26, and the flow cooling channel 23 and the first guide bar groove 251 are not connected to each other, thereby ensuring the isolation between the cooling medium in the cooling channel and the rotor conductor.

[0056] Further, as shown in Figures 3 to 6, the first guide groove 251 and the second guide groove 261 have the same structural form. The inner diameters of both the first guide groove 251 and the second guide groove 261 gradually decrease in the direction towards the central hole 28, forming a trapezoidal hole structure. Multiple first guide grooves 251 on the first rotor lamination 25 are formed around the inner circumference, with the top ends of the multiple first guide grooves 251 located on the same circumference and the bottom ends of the multiple first guide grooves 251 located on another circumference. Similarly, multiple second guide grooves 261 on the second rotor lamination 26 are formed around the inner circumference, with the top ends of the multiple second guide grooves 261 located on the same circumference and the bottom ends of the multiple second guide grooves 261 located on another circumference.

[0057] In some embodiments, end rings 30 are also provided at both axial ends of the rotor core 20. When the cooling medium is sprayed out from both axial ends of the rotor core 20, it can eventually be sprayed onto the end rings 30 to achieve cooling of the end rings 30.

[0058] A second aspect of this disclosure provides an electric motor including the rotor described above, which has all embodiments of the rotor described above and therefore has all the beneficial effects of the rotor described above, which will not be described in detail here.

[0059] Furthermore, this motor can be used in vehicles or other devices that require the use of a motor, all of which are within the scope of protection of this disclosure and are not limited herein.

[0060] In the description of this disclosure, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0063] Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A rotor, characterized in that, The rotor includes: The rotor shaft (10) has a hollow cavity (11) for injecting cooling medium, and a guide hole (12) is provided inside the rotor shaft (10) for guiding the cooling medium radially. The rotor core (20) is coaxially disposed on the outer periphery of the rotor shaft (10). The rotor core (20) is provided with an axial cooling channel (24) communicating with the guide hole (12) near the outer peripheral wall. The axial cooling channel (24) extends from the middle of the rotor core (20) to both axial ends of the rotor core (20).

2. The rotor according to claim 1, characterized in that, The rotor core (20) is also provided with a flow cooling channel (23) in the middle. One end of the flow cooling channel (23) is connected to the flow guide hole (12), and the other end is connected to the axial cooling channel (24).

3. The rotor according to claim 2, characterized in that, The rotor core (20) includes an intermediate section (21) and end sections (22) connected to the two axial sides of the intermediate section (21). The cooling channel (23) is opened on the intermediate section (21), and the end sections (22) are each provided with the axial cooling channel (24). The axial cooling channels (24) of the two end sections extend in opposite directions.

4. The rotor according to claim 3, characterized in that, The intermediate section (21) is formed by stacking multiple first rotor laminations (25) in sequence. Multiple first flow channel holes and first guide bar grooves (251) are evenly spaced along the circumference of the first rotor laminations (25). The first flow channel holes are located between two first guide bar grooves (251). The multiple first flow channel holes on each first rotor lamination (25) are connected one-to-one to form the flow cooling channel (23).

5. The rotor according to claim 4, characterized in that, The cooling channel (23) includes an axial section (231) and a radial section (232) that are interconnected. The axial section (231) is located between the outer peripheral wall of the first guide groove (251) and the intermediate section (21), and the radial section (232) extends from the axial section (231) to the middle of the intermediate section (21).

6. The rotor according to claim 5, characterized in that, A connecting channel (27) is formed between the outer peripheral wall of the rotor shaft (10) and the inner peripheral wall of the first rotor lamination (25). One side of the connecting channel (27) is connected to the guide hole (12), and the other side is connected to the radial section (232).

7. The rotor according to any one of claims 4 to 6, characterized in that, At least one first guide bar groove (251) is provided between any two adjacent flow cooling channels (23).

8. The rotor according to any one of claims 3 to 7, characterized in that, The end section (22) is formed by stacking multiple second rotor laminations (26) in sequence. Multiple second flow channel holes and second guide grooves (261) are evenly spaced along the circumference of the second rotor laminations (26). The second guide grooves (261) extend radially. The second flow channel holes are opened corresponding to the second guide grooves (261) and are located between the second guide grooves (261) and the inner circumferential wall of the end section (22). The multiple second flow channel holes on each second rotor lamination (26) are connected one-to-one to form the axial cooling channel (24).

9. An electric motor, characterized in that, Includes the rotor according to any one of claims 1 to 8.

10. An electric drive system, characterized in that, Includes the motor according to claim 9.

11. A vehicle, characterized in that, Includes the electric drive system according to claim 10.

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