Electric machine rotor assembly, electric machine, vehicle

Abstract

The application provides a motor rotor assembly, a motor and a vehicle, wherein the motor rotor assembly comprises: a rotating shaft which is a hollow sleeve structure with a central sealed space; a rotor core which is sleeved on the outer peripheral wall of the rotating shaft; a first cooling flow channel is arranged on the rotor core; the shaft wall of the rotating shaft is provided with a flow hole; the rotating shaft is further provided with a cooling liquid introduction structure which can introduce external cooling liquid into the central sealed space; after the external cooling liquid is introduced into the central sealed space, the external cooling liquid enters the first cooling flow channel through the flow hole and flows out from the rotor core. According to the application, the external cooling liquid can be introduced into the inside of the rotor core through the hollow sleeve structure of the rotating shaft, so that the efficient cooling and heat dissipation of the rotor core can be realized, the temperature rise caused by the insufficient cooling of the rotor core is effectively prevented, the high-temperature demagnetization phenomenon of the magnetic steel arranged in the rotor core is effectively prevented, and the performance of the motor is improved.

Description

Technical Field

[0001] This invention belongs to the field of motor manufacturing technology, specifically relating to a motor rotor assembly, a motor, and a vehicle. Background Technology

[0002] With the continuous development of the new energy vehicle industry, the main drive motors used in electric vehicles are also constantly evolving, and the market is gradually adopting permanent magnet synchronous motors as the mainstream solution. The actual operating conditions of electric vehicles are harsh and complex. During rapid acceleration and low-speed cruising on long slopes, the motor needs to output extremely high torque, resulting in extremely high current and winding losses, generating a large amount of heat and significantly increasing the motor's temperature. In extreme cases, this can damage the motor. Therefore, most electric vehicle main drive motors now use air cooling for low-end models, water cooling for mid-range models, and more efficient oil cooling for high-end models.

[0003] During actual operation, when the main drive motor of a new energy vehicle is at low speed and high torque, the stator of the main drive motor will generate a lot of heat. There are many ways in existing oil cooling technology to cool the end part of the heat source winding of the main drive motor stator. The coolant is sprayed directly onto the end of the front and rear windings, absorbs the heat, and flows out from the guide groove at the bottom of the housing. After being cooled by the radiator, it is re-introduced into the motor for spraying.

[0004] Oil cooling technology is primarily used in high-end passenger vehicles because it offers superior heat dissipation compared to water cooling. Unlike water cooling, which only conducts heat from the windings to the stator core and then from the stator core to the engine casing, ultimately being carried away by the circulating water in the cooling channels, oil cooling can directly spray heat onto the front and rear ends of the windings where the heat is most intense. When new energy electric vehicles need to enter rapid start-up or sudden acceleration conditions, a large current must pass through the windings in a short period to obtain high torque. This large current causes the windings to overheat significantly. Only an oil cooling solution can effectively remove the heat from the winding ends in time, which is why oil cooling technology began to be used. The main reason for the high-end electric passenger car is oil cooling, but there is still a problem to be solved. When the motor enters the high speed range, the rotor speed can reach more than 10,000 rpm. At this high speed, the magnets will heat up due to the huge increase in eddy current losses, which will cause the rotor to heat up. At present, there is no solution for cooling the rotor, which means that the rotor can only conduct heat through the motor shaft and radiate a small amount of heat to the air inside the motor. If the rotor temperature remains high, there is a risk of demagnetization of the rare earth permanent magnet material magnets, which will cause a permanent decline in motor performance. Summary of the Invention

[0005] Therefore, the present invention provides a motor rotor assembly, a motor, and a vehicle that can overcome the shortcomings of the prior art, such as insufficient cooling of the rotor core and high rotor temperature, which leads to demagnetization of the magnets and reduced motor performance.

[0006] To address the above problems, the present invention provides a motor rotor assembly, comprising:

[0007] The rotating shaft is a hollow bushing structure with a central sealed space;

[0008] The rotor core is fitted onto the outer peripheral wall of the shaft.

[0009] The rotor core is provided with a first cooling channel, the shaft wall of the rotating shaft has a flow hole, and the rotating shaft also has a coolant introduction structure that can introduce external coolant into the central sealed space. After the external coolant is introduced into the central sealed space, it enters the first cooling channel through the flow hole and flows out from the rotor core.

[0010] In some implementations...

[0011] A liquid equalization structure is provided in the central sealed space. There are multiple flow holes, which are spaced apart circumferentially along the rotating shaft. The liquid equalization structure includes multiple liquid equalization arms and coolant inlets communicating with the multiple liquid equalization arms. The multiple liquid equalization arms and the multiple flow holes are respectively arranged in a one-to-one correspondence.

[0012] In some implementations...

[0013] The equalizing arm is a strip that extends axially along the rotating shaft.

[0014] In some implementations...

[0015] The hollow bushing structure has multiple grooves extending axially along the rotating shaft on its inner peripheral wall, and the liquid equalization arm is inserted into the grooves.

[0016] In some implementations...

[0017] The cross-sectional shape of the groove is T-shaped, and the horizontal segment of the T-shape is located on the side away from the central sealing space; the cross-sectional shape of the liquid equalization arm is adapted to the cross-sectional shape of the groove; and / or,

[0018] The liquid equalization arm has a strip-shaped liquid outlet on the side facing the groove.

[0019] In some implementations...

[0020] The rotating shaft includes a rotor core assembly section and long shaft sections and short shaft sections assembled at both axial ends of the rotor core assembly section. The rotor core assembly section has an axially extending central through hole. The long shaft sections and short shaft sections together with the central through hole form the central sealed space.

[0021] In some implementations...

[0022] The coolant inlet structure includes an axial liquid inlet section constructed on the side of the long axis section facing the short axis section. The outlet of the axial liquid inlet section is connected to the coolant inlet section, and the coolant flow direction in the axial liquid inlet section is opposite to the coolant flow direction in the liquid equalization arm.

[0023] In some implementations...

[0024] The first cooling channel includes a radial channel and an axial channel, and the rotor core includes a first core and a second core stacked axially along the shaft, wherein the axial channel is constructed on the first core and the radial channel is constructed on the second core.

[0025] In some implementations...

[0026] The second iron core is formed by stacking multiple second laminations, each lamination having multiple radially extending grooves, each radially extending groove corresponding to the flow hole, and the stacking height of the second iron core being equal to the diameter of the flow hole.

[0027] In some implementations...

[0028] The first iron core is formed by stacking multiple first laminations, each of which has multiple arc grooves spaced apart along its circumference, and each arc groove is connected to each radial strip groove.

[0029] In some implementations...

[0030] The first core is stacked on at least one axial end of the second core. The first core has a core end plate on the side away from the second core. The core end plate has a plurality of coolant outlet pipes. The outlet direction of the coolant outlet pipes is toward the winding end of the stator assembly that matches the motor rotor assembly.

[0031] The present invention also provides an electric motor, including the above-described motor rotor assembly.

[0032] In some embodiments, the motor further includes:

[0033] The housing has a second cooling channel inside, the position of which is adapted to the position of the stator assembly. The coolant in the second cooling channel is water, and the coolant in the first cooling channel is cooling oil.

[0034] The present invention also provides a vehicle, including a main drive motor, wherein the main drive motor is the motor described above.

[0035] The present invention provides a motor rotor assembly, a motor, and a vehicle, which can introduce external coolant into the interior of the rotor core through the hollow bushing structure of the rotating shaft, thereby achieving efficient cooling and heat dissipation of the rotor core, effectively preventing temperature rise due to insufficient cooling of the rotor core, and thus effectively preventing high-temperature demagnetization of the magnets installed in the rotor core, thereby improving motor performance. Attached Figure Description

[0036] Figure 1 This is an exploded structural diagram of the motor rotor assembly according to an embodiment of the present invention;

[0037] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0038] Figure 3 This is a partial cross-sectional view of the rotor core of the motor rotor assembly according to an embodiment of the present invention.

[0039] Figure 4 for Figure 3 A schematic diagram of the structure of the first lamination;

[0040] Figure 5 for Figure 3 Schematic diagram of the structure of the second lamination;

[0041] Figure 6 This is a schematic diagram (partial cross-sectional view) of the structure of the core end plate at the end of the rotor core in the motor rotor assembly of the present invention.

[0042] Figure 7 This is a schematic diagram (partial cross-sectional view) of the internal structure of a motor according to another embodiment of the present invention;

[0043] Figure 8 This diagram illustrates the connection between the motor and an external cooling source, as well as the flow of the cooling medium (oil or water) according to another embodiment of the present invention (indicated by arrows in the figure).

[0044] The reference numerals in the attached figures are as follows:

[0045] 1. Rotating shaft; 11. Flow hole; 12. Slot; 13. Rotor core assembly section; 14. Long shaft section; 15. Short shaft section; 16. Axial liquid guiding section; 2. Rotor core; 31. Liquid distribution arm; 311. Strip-shaped liquid outlet; 32. Coolant inlet; 41. Axial flow channel; 42. Radial flow channel; 51. First core; 511. First lamination; 512. Arc groove; 52. Second core; 521. Second lamination; 522. Radial strip groove; 61. Core end plate; 62. Coolant outlet pipe; 71. Oil pump; 72. Oil heat exchanger; 81. Water pump; 82. Water heat exchanger; 100. Stator assembly; 101. Winding end; 200. Housing; 201. Second cooling flow channel. Detailed Implementation

[0046] See also Figures 1 to 8 As shown, according to an embodiment of the present invention, a motor rotor assembly is provided, comprising: a shaft 1, which is a hollow bushing structure with a central sealed space; a rotor core 2, which is fitted onto the outer peripheral wall of the shaft 1; a first cooling channel is constructed on the rotor core 2; a flow hole 11 is provided on the shaft wall of the shaft 1 (i.e., the cylindrical wall of the hollow bushing structure); the shaft 1 also has a coolant introduction structure capable of introducing external coolant (specifically, for example, cooling oil) into the central sealed space; after the external coolant is introduced into the central sealed space, it enters the first cooling channel (not indicated in the figure) through the flow hole 11 and flows out from the rotor core 2. In this technical solution, external coolant can be introduced into the interior of the rotor core 2 through the hollow bushing structure of the rotating shaft 1, thereby achieving efficient cooling and heat dissipation of the rotor core 2, and timely removing the heat generated by the rotor core 2 and the magnets on it, effectively preventing the temperature rise caused by insufficient cooling of the rotor core 2, and thus effectively preventing the high-temperature demagnetization of the magnets (especially permanent magnets) installed in the rotor core 2, thereby improving the motor performance.

[0047] Specifically, the external coolant can be directly introduced into the central sealed space. After the coolant fills the central sealed space, it can be forced into the first cooling channel to cool the rotor core 2. However, this method requires a large amount of coolant, which increases the mass of the shaft 1 and is not conducive to the rotation control of the shaft 1. In addition, due to the rotation of the shaft 1, this method is not easy to evenly distribute the coolant into the multiple flow holes 11. In some embodiments, a liquid equalization structure is provided in the central sealed space, and there are multiple flow holes 11. The holes 11 are spaced apart circumferentially along the rotating shaft 1. The liquid distribution structure includes multiple liquid distribution arms 31 and coolant inlets 32 communicating with the multiple liquid distribution arms 31. Each of the multiple liquid distribution arms 31 corresponds to one of the multiple flow holes 11. In this technical solution, the multiple liquid distribution arms 31 achieve targeted distribution of coolant introduced through the coolant inlets 32. On the one hand, this reduces the amount of coolant used, decreases the rotor's rotational inertia, and facilitates control. On the other hand, it promotes uniform distribution of coolant circumferentially in the rotor core 2, thereby ensuring a consistent circumferential temperature of the rotor core 2. Ideally, the multiple liquid distribution arms 31 are evenly spaced circumferentially in the rotor core 2. Figure 1 As shown, there are four equalizing arms 31 (the equalizing structure at this time is a five-way structure). The four equalizing arms 31 are evenly spaced in the circumferential direction of the rotating shaft 1, so that the mass of the rotating shaft 1 is more uniform in the circumferential direction and the dynamic balance is better.

[0048] The liquid equalization arm 31 is a strip extending along the axial direction of the rotating shaft 1. The strip-shaped liquid equalization arm 31 can have a larger contact area with the rotating shaft 1 and / or the central sealing space, which is also beneficial for cooling and heat dissipation of the rotating shaft 1.

[0049] In one specific embodiment, the inner peripheral wall of the hollow bushing structure has a plurality of grooves 12 extending axially along the rotating shaft 1. The liquid equalization arm 31 is inserted into the grooves 12. The insertion relationship between the grooves 12 and the liquid equalization arm 31 can realize the reliable fixation and assembly of the liquid equalization structure, effectively preventing quality problems caused by unreliable connection of the liquid equalization structure during the rotation of the rotating shaft 1.

[0050] See Figure 2As shown, the cross-sectional shape of the groove 12 is T-shaped, and the horizontal segment of the T-shape is located on the side away from the central sealed space. The cross-sectional shape of the liquid equalization arm 31 is adapted to the cross-sectional shape of the groove 12, so that the T-shaped constriction positioning structure can be used to further ensure the reliable and stable position of the liquid equalization structure in the central sealed space. It should be noted that when the liquid equalization arm 31 is inserted into the groove 12, the sealing performance between the liquid equalization arm 31 and the groove 12 should be ensured to prevent the coolant in the liquid equalization arm 31 from leaking out. For example, the aforementioned sealing effect can be achieved by applying sealant to the outer peripheral wall of the liquid equalization arm 31 before insertion.

[0051] The flow passage 11 can be arranged in multiple rows at intervals along the axial direction of the rotating shaft 1. In one embodiment, the liquid equalization arm 31 has a strip-shaped liquid outlet 311 on the side facing the groove 12. The strip-shaped liquid outlet 311 can communicate with multiple rows of flow passage 11 in the same axial direction at the same time, simplifying the connection structure of the liquid circuit.

[0052] The rotating shaft 1 includes a rotor core assembly section 13 and long shaft sections 14 and short shaft sections 15 assembled at both axial ends of the rotor core assembly section 13. The rotor core assembly section 13 has an axially extending central through hole. The long shaft sections 14 and 15, together with the central through hole, form the central sealing space. The rotating shaft 1 is formed by assembling the three shaft sections, which facilitates the assembly of the liquid equalization structure within the central sealing space. It should be noted that the long shaft section 14 and 15 each have a shoulder structure that pivotally connects to the corresponding motor end cover. The long shaft section 14 and 15 can be welded to both ends of the rotor core assembly section 13, for example, to jointly position the liquid equalization structure axially. Of course, the long shaft section 14 and 15 can also be detachably connected to both ends of the rotor core assembly section 13 (e.g., with an interference fit).

[0053] The coolant introduction structure includes an axial liquid inlet section 16 constructed on the side of the long shaft section 14 facing the short shaft section 15. The outlet of the axial liquid inlet section 16 is connected to the coolant inlet 32, and the coolant flow direction in the axial liquid inlet section 16 is opposite to the coolant flow direction in the liquid distribution arm 31. That is, the axial length of the axial liquid inlet section 16 is approximately equal to the axial length of the rotor core assembly section 13, thereby enabling the coolant to have a large flow path in the central sealed space, which can effectively cool the rotor core 2 while also effectively reducing the temperature in the central sealed space.

[0054] See details Figure 3As shown, the first cooling channel includes a radial channel 42 and an axial channel 41. The rotor core 2 includes a first core 51 and a second core 52 stacked along the axial direction of the rotating shaft 1. The axial channel 41 is constructed on the first core 51, and the radial channel 42 is constructed on the second core 52. The radial channel 42 can introduce the coolant in the liquid distribution structure radially into the axial channel 41, while the axial channel 41 can flow along the axial direction of the rotor core 2 to form heat exchange with the rotor core 2, thereby achieving the cooling purpose. Specifically, the second core 52 is formed by stacking multiple second laminations 521. Each second lamination 521 has multiple radially extending radial grooves 522. The position of each radial groove 522 corresponds to the flow hole 11, and the stack height of the second core 52 is equal to the diameter of the flow hole 11. The first core 51 is formed by stacking multiple first laminations 511, such as... Figure 4 As shown, the first lamination 511 has a plurality of arc grooves 512 spaced apart along its circumference, each arc groove 512 correspondingly communicating with each radial strip groove 522. The circumferential extension length (arc length) of the arc groove 512 should be as large as possible while ensuring that the first lamination 511 has sufficient structural strength and does not affect the magnetic flux density saturation, and should be as close as possible to the magnet that heats up due to eddy current losses. When the coolant flows at the arc groove 512, it can effectively remove the heat generated by the magnet and rotor due to eddy current losses.

[0055] In some embodiments, the first core 51 is stacked on at least one axial end of the second core 52. The first core 51 has a core end plate 61 on its side away from the second core 52. The core end plate 61 has multiple coolant outlet pipes 62. The coolant outlet pipes 62 are directed towards the winding end 101 in the stator assembly 100 that matches the motor rotor assembly, so that the coolant flowing out of the arc groove 512 can be further thrown onto the winding end 101, thereby further cooling the winding end 101. It should be noted that in this technical solution, by setting corresponding coolant outlet pipes 62 on the core end plate 61, the centrifugal force of the rotating motor rotor assembly can be used to throw the coolant onto the winding end 101, achieving effective cooling of the winding end without modifying other structures of the motor. This is simple and easy to implement. The coolant outlet pipes 62 can be implemented, for example, using a converging nozzle. It should be noted that in the existing technology, cooling of the winding ends is mostly achieved by setting corresponding oil injection rings nearby. This method has a relatively complex structure and is difficult to distribute the flow, so the corresponding oil circuit structure design is complicated.

[0056] It should be noted that the number of segments of the second iron core 52 corresponds to the number of rows of the flow holes 11 in the axial direction of the rotating shaft 1. In a specific embodiment, the first iron core 51 is stacked on both ends of the second iron core 2 in the axial direction.

[0057] According to an embodiment of the present invention, a motor is also provided, including the motor rotor assembly described above. See details. Figure 7 The motor further includes a housing 200, which internally contains a second cooling channel 201. The position of the second cooling channel 201 is adapted to the position of the stator assembly 100. The coolant in the second cooling channel 201 is water, and the coolant in the first cooling channel is a coolant. In this technical solution, the second cooling channel 201 on the housing 200 uses water cooling to cool the stator assembly 100, while the first cooling channel in the motor rotor assembly uses oil cooling to cool the rotor core 2, the shaft 1, and the winding ends 101, thereby effectively ensuring the performance of the motor. This effectively avoids the problem in the prior art where, due to the conductive and corrosive properties of water, the cooling water can only circulate within the housing interlayer. The stator core transfers heat to the housing through thermal conduction, and the heat is carried away by the flow of circulating water. This single cooling method easily leads to uneven stator cooling and the formation of localized heat islands. This technical solution can dissipate heat from the middle of the winding, the ends of the winding, and inside the rotor core. It can be applied to motor designs with higher heat loads, improving motor performance and operational stability.

[0058] like Figure 8 As shown, in a specific embodiment, an oil pump 71 and an oil heat exchanger 72 located outside the motor are used to achieve oil cooling circulation of the motor, and a water pump 81 and a water heat exchanger 82 located outside the motor are used to achieve water cooling circulation of the motor.

[0059] The present invention also provides a vehicle, including a main drive motor, wherein the main drive motor is the motor described above.

[0060] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A motor rotor assembly, characterized in that, include: The rotating shaft (1) is a hollow bushing structure with a central sealed space; The rotor core (2) is fitted onto the outer peripheral wall of the rotating shaft (1); The rotor core (2) is provided with a first cooling channel. The shaft wall of the rotating shaft (1) has a flow hole (11). The rotating shaft (1) also has a coolant inlet structure that can introduce external coolant into the central sealed space. After the external coolant is introduced into the central sealed space, it enters the first cooling channel through the flow hole (11) and flows out from the rotor core (2). A liquid equalization structure is provided in the central sealed space. There are multiple flow holes (11). The multiple flow holes (11) are arranged circumferentially along the rotating shaft (1). The liquid equalization structure includes multiple liquid equalization arms (31) and a coolant inlet (32) communicating with the multiple liquid equalization arms (31). The multiple liquid equalization arms (31) and the multiple flow holes (11) are respectively arranged one-to-one. The liquid distribution arm (31) is a strip extending axially along the rotating shaft (1). The inner peripheral wall of the hollow bushing structure has a plurality of grooves (12) extending axially along the rotating shaft (1). The liquid distribution arm (31) is inserted into the grooves (12). The rotating shaft (1) includes a rotor core assembly section (13) and a long shaft section (14) and a short shaft section (15) assembled at both ends of the rotor core assembly section (13). The coolant introduction structure includes an axial liquid guide section (16) constructed on the side of the long shaft section (14) facing the short shaft section (15). The outlet of the axial liquid guide section (16) is connected to the coolant inlet (32), and the coolant flow direction in the axial liquid guide section (16) is opposite to the coolant flow direction in the liquid distribution arm (31).

2. The motor rotor assembly according to claim 1, characterized in that, The cross-sectional shape of the groove (12) is T-shaped, and the transverse segment of the T-shape is located on the side away from the central sealing space. The cross-sectional shape of the liquid equalization arm (31) is adapted to the cross-sectional shape of the groove (12); and / or, The liquid equalization arm (31) has a strip-shaped liquid outlet (311) on the side facing the strip groove (12).

3. The motor rotor assembly according to claim 1, characterized in that, The rotor core assembly section (13) has an axially extending central through hole, and the long shaft section (14) and the short shaft section (15) together with the central through hole form the central sealing space.

4. The motor rotor assembly according to claim 1, characterized in that, The first cooling channel includes a radial channel (42) and an axial channel (41). The rotor core (2) includes a first core (51) and a second core (52) stacked axially along the shaft (1). The axial channel (41) is constructed on the first core (51), and the radial channel (42) is constructed on the second core (52).

5. The motor rotor assembly according to claim 4, characterized in that, The second iron core (52) is formed by stacking multiple second laminations (521), each of which has multiple radially extending slots (522) that correspond to the flow hole (11), and the stack height of the second iron core (52) is equal to the diameter of the flow hole (11).

6. The motor rotor assembly according to claim 5, characterized in that, The first iron core (51) is formed by stacking multiple first laminations (511). Each first lamination (511) has multiple arc grooves (512) spaced apart along its circumference. Each arc groove (512) is connected to each radial strip groove (522).

7. The motor rotor assembly according to claim 4, characterized in that, The first core (51) is stacked on at least one axial end of the second core (52). The first core (51) has a core end plate (61) on the side away from the second core (52). The core end plate (61) has a plurality of coolant outlet pipes (62). The outlet direction of the coolant outlet pipes (62) is toward the winding end (101) in the stator assembly (100) that matches the motor rotor assembly.

8. An electric motor, characterized in that, Includes the motor rotor assembly according to any one of claims 1 to 7.

9. The motor according to claim 8, characterized in that, Also includes: The housing (200) has a second cooling channel (201) inside, the position of the second cooling channel (201) is adapted to the position of the stator assembly (100), the coolant in the second cooling channel (201) is water, and the coolant in the first cooling channel is cooling oil.

10. A vehicle, comprising a main drive motor, characterized in that, The main drive motor is the motor described in claim 8 or 9.

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