A rotor structure, an electric motor

Abstract

This utility model provides a rotor structure and a motor. The rotor structure includes a rotor core with magnetic slots and through holes. The through holes and magnetic slots are arranged radially spaced along the rotor core. Multiple first grooves are provided on the inner wall of the magnetic slots. Along the axial direction of the rotor core, the magnetic slots, the first grooves, and the through holes penetrate the rotor core. An impeller assembly is provided at the end of the rotor core, and the impeller assembly is used to deliver airflow into the first grooves and the through holes. According to this utility model, the technical problem of motor rotors failing to cool their internal components, leading to reduced motor performance, can be solved.

Description

Technical Field

[0001] This utility model belongs to the field of motor technology, specifically relating to a rotor structure and a motor. Background Technology

[0002] High-speed motors typically use magnetic or air bearings to suspend the rotor, making it levitate in the air. This results in zero mechanical friction during operation, effectively reducing losses and heat generation. Furthermore, it offers advantages such as no lubrication required and no oil pollution, significantly increasing the motor's critical speed and extending its lifespan. High-speed motor rotors are currently divided into surface-mounted and internal types, representing the main research direction. This patent proposal primarily focuses on internal high-speed motor rotors.

[0003] When existing built-in high-speed motor rotors are used in motors with air cooling, they only dissipate heat on the surface of the rotor and cannot cool the inside of the rotor. Since the rotor is located inside the motor, and due to the wind friction of high-speed rotation and the alternating electromagnetic field, the rotor temperature is very high. In some cases, the rotor temperature can reach nearly 300 degrees Celsius, which seriously affects the performance of permanent magnets and even poses a risk of demagnetization. To meet the requirements, expensive high-temperature resistant permanent magnets must be selected, which will also cause performance degradation.

[0004] Because existing motor rotors cannot cool their internal components, leading to reduced motor performance, this invention addresses this problem by designing a rotor structure and a motor. Utility Model Content

[0005] Therefore, this utility model provides a rotor structure and a motor that can solve the technical problem in the prior art where the motor rotor cannot cool its internal components, resulting in reduced motor performance.

[0006] To address the aforementioned problems, this utility model provides a rotor structure, comprising: a rotor core, wherein the rotor core is provided with magnetic slots and through holes, the through holes and the magnetic slots are arranged radially spaced along the rotor core, and a plurality of first grooves are provided on the inner wall of the magnetic slots; along the axial direction of the rotor core, the magnetic slots, the first grooves and the through holes penetrate the rotor core, and an impeller assembly is provided at the end of the rotor core, the impeller assembly being used to convey airflow into the first grooves and the through holes.

[0007] In some embodiments, a magnet is provided in the magnet groove, and the magnet and the first groove enclose a first channel. The impeller assembly is provided at both ends of the rotor core. The rotor core and the impeller assembly are sleeved on the rotating shaft. One impeller assembly is used to deliver airflow into the first channel and the through hole, and the other impeller assembly is used to extract the airflow from the first channel and the through hole.

[0008] In some embodiments, the through holes are arranged at intervals along the circumference of the rotor core, and the through holes correspond one-to-one with the magnet slots; the first groove is located on the inner wall of the magnet slot near the through hole.

[0009] In some embodiments, the impeller assembly includes a body having a cavity, the cavity including a base plate and a panel, the panel having an opening communicating with the cavity, the base plate having a second groove penetrating the base plate and communicating with the cavity, and a plurality of impellers being disposed within the cavity.

[0010] In some embodiments, the base plate abuts against the end face of the rotor core, the second groove has multiple grooves, the multiple second grooves are arranged at intervals along the circumference of the main body, and the second grooves are connected to the first groove and the through hole.

[0011] In some embodiments, a first gap is provided between the panel and the rotating shaft, the gap forming the opening, and a second gap is provided between the impeller and the rotating shaft, the width of the first gap being greater than the width of the second gap.

[0012] In some embodiments, the impeller is disposed on the base plate, the impeller is arc-shaped along the radial direction of the body, and the impeller extends along the rotation direction of the shaft.

[0013] In some embodiments, with the cross-section of the rotor core as the projection plane, the second groove is U-shaped, and the second groove has a first segment, a second segment and a third segment. The second segment is located between the first segment and the third segment, and the second segment is arranged opposite to the first groove. The first segment and the third segment are arranged opposite to the through hole.

[0014] In some embodiments, one end of the impeller is arranged close to the second groove, the other end of the impeller is arranged close to the shaft, and one end of the impeller is straight, with the first segment and the third segment arranged opposite to one end of the impeller.

[0015] This utility model also provides an electric motor, which includes the aforementioned rotor structure.

[0016] The rotor structure and motor provided by this utility model have the following beneficial effects:

[0017] By setting an impeller assembly at the end of the rotor core, and setting a through hole and the first groove in the magnet slot on the rotor core, when the rotor core rotates, the impeller assembly quickly delivers airflow to the through hole and the first groove, thereby cooling the rotor core and the magnet, improving the cooling efficiency of the rotor. In addition, the through hole can also reduce the unnecessary weight of the rotor core, thereby reducing the weight of the rotor, reducing the rotational inertia of the rotor, and improving the performance of the rotor. Attached Figure Description

[0018] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 This is an assembly structure diagram of the rotor structure of this utility model;

[0020] Figure 2 This is the assembly structure of the rotor structure of this utility model. Figure 2 ;

[0021] Figure 3 This is a side view of the rotor structure of this utility model;

[0022] Figure 4 yes Figure 1 Sectional view of AA;

[0023] Figure 5 This is a partial cross-sectional view of the rotor structure of this utility model;

[0024] Figure 6 This is the assembly structure of the rotor structure of this utility model. Figure 3 ;

[0025] Figure 7 This is the assembly structure of the rotor structure of this utility model. Figure 4 ;

[0026] Figure 8 This is the assembly structure of the rotor structure of this utility model. Figure 5 ;

[0027] Figure 9 This is the assembly structure of the rotor structure of this utility model. Figure 6 ;

[0028] Figure 10 This is the assembly structure of the rotor structure of this utility model. Figure 7 ;

[0029] Figure 11 This is an exploded view of the rotor structure of this utility model;

[0030] Figure 12 This is a schematic diagram of the rotor core structure in the rotor structure of this utility model. Figure 1 ;

[0031] Figure 13 This is a schematic diagram of the rotor core structure in the rotor structure of this utility model. Figure 2 ;

[0032] Figure 14 This is a schematic diagram of the rotor core structure in the rotor structure of this utility model. Figure 3 ;

[0033] Figure 15 This is a schematic diagram of the impeller assembly in the rotor structure of this utility model. Figure 1 ;

[0034] Figure 16 This is a side view of the impeller assembly in the rotor structure of this utility model;

[0035] Figure 17 This is a schematic diagram of the impeller assembly in the rotor structure of this utility model. Figure 2 ;

[0036] Figure 18 This is a schematic diagram of the impeller assembly in the rotor structure of this utility model. Figure 3 ;

[0037] Figure 19 This is a schematic diagram of the impeller assembly in the rotor structure of this utility model. Figure 4 ;

[0038] Figure 20 This is a schematic diagram of the impeller assembly in the rotor structure of this utility model. Figure 5 ;

[0039] Figure 21 This is a schematic diagram of the impeller assembly in the rotor structure of this utility model. Figure 6 .

[0040] The attached figures are labeled as follows:

[0041] 1. Rotor core; 2. Impeller assembly; 3. Shaft; 4. Through hole; 5. First groove; 6. Magnet; 7. Magnet groove; 8. Main body; 9. Cavity; 10. Base plate; 11. Panel; 12. Second groove; 13. Impeller. Detailed Implementation

[0042] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0043] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0044] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0045] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0046] See also Figure 1-21As shown, according to an embodiment of the present invention, a rotor structure is provided, comprising: a rotor core 1, wherein the rotor core 1 is provided with a magnetic steel groove 7 and a through hole 4, the through hole 4 and the magnetic steel groove 7 are arranged radially spaced along the rotor core 1, and a plurality of first grooves 5 are provided on the inner wall of the magnetic steel groove 7; along the axial direction of the rotor core 1, the magnetic steel groove 7, the first grooves 5 and the through hole 4 penetrate the rotor core 1, and an impeller assembly 2 is provided at the end of the rotor core 1, the impeller assembly 2 being used to transport airflow to the first grooves 5 and the through hole 4.

[0047] In this technical solution, by setting an impeller assembly 2 at the end of the rotor core 1, and setting a through hole 4 on the rotor core 1, as well as the first groove 5 in the magnet slot 7, when the rotor core 1 rotates, the impeller assembly 2 quickly delivers airflow to the through hole 4 and the first groove 5, thereby cooling the rotor core 1 and the magnet 6, improving the cooling efficiency of the rotor. In addition, the through hole 4 can also reduce the unnecessary weight of the rotor core 1, thereby reducing the weight of the rotor, reducing the rotational inertia of the rotor, and improving the performance of the rotor.

[0048] In the rotor structure of this utility model, the rotor core 1 is made of stacked silicon steel sheets. The part of the silicon steel sheets other than the position where the magnet is placed has evenly distributed through holes to reduce the weight of the stacked rotor core. The evenly distributed slots are conducive to the dynamic balance of the rotor. At the same time, the through holes are also channels for cooling air and increase the heat dissipation area of ​​the rotor, thus providing a basis for achieving efficient heat dissipation.

[0049] In some embodiments, a magnet 6 is provided in the magnet groove 7, and the magnet 6 and the first groove 5 enclose a first channel. The impeller assembly 2 is provided at both ends of the rotor core 1. The rotor core 1 and the impeller assembly 2 are sleeved on the rotating shaft 3. One impeller assembly 2 is used to deliver airflow into the first channel and the through hole 4, and the other impeller assembly 2 is used to extract the airflow from the first channel and the through hole 4.

[0050] In this technical solution, impeller assemblies 2 are provided at both ends of the rotor core 1. One impeller assembly 2 is used to deliver airflow into the first channel and the through hole 4, and the other impeller assembly 2 is used to extract the airflow from the first channel and the through hole 4, thereby accelerating the flow speed of the airflow in the first channel and the through hole 4 and improving the cooling efficiency.

[0051] In the rotor structure of this utility model, a semi-circular first groove 5 is developed at the position of the silicon steel sheet where the magnet is placed, which is used to form a first channel at the position of the magnet, so that cooling air can directly pass through the surface of the magnet and take away the heat of the magnet, thereby achieving magnet cooling.

[0052] In some embodiments, the through holes 4 are arranged at intervals along the circumference of the rotor core 1, and the through holes 4 are arranged in a one-to-one correspondence with the magnet slots 7; the first groove 5 is located on the inner wall of the magnet slot 7 near the through holes 4.

[0053] In this technical solution, the through holes 4 and the magnetic grooves 7 are arranged in a one-to-one correspondence. Even if the impeller assembly 2 cools the through holes 4 and the first groove 5 at the same time, the weight of the rotor core can be reduced to the greatest extent and the rotor dynamic performance can be improved.

[0054] In some embodiments, the impeller assembly 2 includes a body 8, the body 8 having a cavity 9, the cavity 9 including a base plate 10 and a panel 11, the panel 11 having an opening communicating with the cavity, the base plate 10 having a second groove 12 penetrating the base plate 10 and communicating with the cavity 9, and a plurality of impellers 13 being disposed within the cavity 9.

[0055] In this technical solution, see [reference] Figure 15-21 As shown, a cavity 9 is provided inside the main body 8. One side of the cavity 9 has an opening, and the other side has a second groove 12. The second groove 12 penetrates the bottom plate 10. Furthermore, the second groove 12 can input airflow into the through hole 4 and the first groove 5, or extract airflow from the through hole 4 and the first groove 5. The opening is used to deliver airflow into the cavity 9 or extract airflow from the cavity 9. Multiple impellers 13 are also provided inside the cavity 9. Under the action of the impellers 13, the airflow flows rapidly through the opening and the second groove 12, thereby cooling the rotor core 1.

[0056] In some embodiments, the base plate 10 abuts against the end face of the rotor core 1, and there are multiple second grooves 12. The multiple second grooves 12 are arranged at intervals along the circumference of the main body 8, and the second grooves 12 are connected to the first groove 5 and the through hole 4.

[0057] In this technical solution, the second groove 12 is arranged in a one-to-one correspondence with the through hole 4. The airflow can be input into the through hole 4 and the first groove 5 through the second groove 12, or the airflow can be extracted from the through hole 4 and the first groove 5, thereby achieving cooling of the rotor core 1.

[0058] In the rotor structure of this utility model, the impeller assemblies at both ends of the rotor core 1 can be designed with different numbers and sizes of blades according to the requirements of rotational speed and heat dissipation air volume, so as to meet the requirements of heat dissipation energy consumption and heat dissipation effect.

[0059] The base plate 10 and the centrifugal impeller 13 are designed as a single unit, which not only meets the structural requirements of the base plate 10 pressing down the silicon steel and the magnet, but also meets the requirements of impeller arrangement and heat dissipation air volume; the base plate 10 achieves dual functions.

[0060] A sealed second groove 12 is designed on the outer circle side of the base plate 10. The second groove 12 is designed with through holes, and the heat dissipation of the magnet is connected to the through holes of the rotor silicon steel sheet to realize the internal circulation of cooling air.

[0061] After the impellers 13 of the base plates 10 at both ends of the rotor core 1 are assembled at both ends of the rotor, according to the rotation direction of the rotor, air can be introduced at one end, compressed air is introduced into the cooling air duct, and air is discharged at the other end, and a vacuum is drawn to allow the air in the cooling air duct to be discharged more quickly.

[0062] The rotor structure of this utility model can generate an air pressure difference as the rotor rotates, allowing cold air to flow quickly through the inside of the rotor core and the surface of the magnets, thereby carrying away the heat of the rotor core and magnets and achieving the purpose of cooling. At the same time, the integrated design of the impeller and the base plate can achieve efficient heat dissipation without increasing the rotor shaft length. Under the same performance output, due to efficient heat dissipation, the amount of magnets and silicon steel can be reduced, thereby shortening the rotor length and improving the rotor dynamic performance.

[0063] In some embodiments, a first gap is provided between the panel 11 and the rotating shaft 3, the gap forming the opening, and a second gap is provided between the impeller 13 and the rotating shaft 3, wherein the width of the first gap is greater than the width of the second gap.

[0064] In this technical solution, a through hole can be provided on the panel 11, or a first gap can be provided between the panel 11 and the rotating shaft 3, and the gap forms the opening. Airflow can be delivered to the cavity 9 or airflow can be extracted from the cavity 9 through the opening. A second gap can be provided between the impeller 13 and the rotating shaft 3. The width of the first gap is greater than the width of the second gap, thereby ensuring that the impeller can draw airflow in or out of the opening and improve the airflow speed.

[0065] In some embodiments, the impeller 13 is disposed on the base plate 10, and the impeller 13 is arc-shaped along the radial direction of the main body 8, and the impeller 13 extends along the rotation direction of the rotating shaft 3.

[0066] In this technical solution, the impeller 13 is arc-shaped and extends along the rotation direction of the rotating shaft 3, so that the impeller 13 can quickly guide the airflow and improve the cooling efficiency of the rotor.

[0067] The rotor structure of this utility model uses through holes 4 and first grooves 5 to remove unnecessary weight from the inner ring, thereby reducing the rotor's weight, moment of inertia, and improving its dynamic performance. This makes it suitable for high-speed motors with frequent frequency conversion speed regulation and improved motor response. The segmented magnets and the first groove 5 structure facilitate rotor processing and assembly, achieve efficient heat dissipation, and solve the problem of high cost associated with using expensive high-temperature resistant magnets. Conventional permanent magnets can be used instead, thus enhancing the motor's cost competitiveness in the market.

[0068] The standardized main body and impeller structure are simple and easy to manufacture, solving the problem of poor heat dissipation when the rotor is cooled by air alone. The rotor's efficient heat dissipation is generated by the impeller rotating with the rotor, avoiding the problem of heat dissipation failure caused by the failure of a separate heat dissipation system, thus eliminating the problem of high-temperature demagnetization of the magnets. The overall rotor heat dissipation structure can generate an air pressure difference as the rotor rotates, allowing cold air to flow quickly through the rotor's interior and the surface of the magnets, thereby carrying away the heat of the rotor and magnets, achieving cooling. The integrated design of the impeller and the base plate can achieve efficient heat dissipation without increasing the rotor shaft length. For the same performance output, due to efficient heat dissipation, the amount of magnets and silicon steel used can be reduced, thereby shortening the rotor length and improving the rotor's dynamic performance.

[0069] In some embodiments, with the cross-section of the rotor core 1 as the projection plane, the second groove 12 is U-shaped, and the second groove 12 has a first segment, a second segment and a third segment. The second segment is located between the first segment and the third segment. The second segment is arranged opposite to the first groove 5, and the first segment and the third segment are arranged opposite to the through hole 4.

[0070] In this technical solution, the second groove 12 is U-shaped, the second section is arranged opposite to the first groove 5, and the first section and the third section are arranged opposite to the through hole 4. This limits the flow area of ​​the airflow channel from the cavity 9 to the through hole 4 and the first groove 5, thereby increasing the airflow velocity and ensuring the rotor cooling effect.

[0071] In some embodiments, one end of the impeller 13 is arranged close to the second groove 12, and the other end of the impeller 13 is arranged close to the rotating shaft 3. Furthermore, one end of the impeller 13 is straight, and the first segment and the third segment are arranged opposite to one end of the impeller 13.

[0072] In this technical solution, one end of the impeller 13 is straight, and the first section and the third section are arranged opposite to one end of the impeller 13, so that the impeller 13 can quickly guide the airflow to the first section and the third section, so that the cold air can quickly flow through the inside of the rotor and the surface of the magnet, thereby taking away the heat of the rotor and the magnet and achieving cooling.

[0073] The rotor structure of this utility model solves the problems of high temperature of permanent magnets in built-in high-speed motor rotors, which leads to the risk of high-temperature demagnetization of permanent magnets, difficulty in raising the temperature of high-speed rotors, difficulty in air cooling of high-speed motor rotors, low heat dissipation efficiency, and decreased rotor dynamic performance due to the long rotor shaft of high-speed motors. At the same time, it does not increase the rotor shaft length or the processing difficulty, and improves the heat dissipation effect, reduces costs, and improves motor efficiency while ensuring that the rotor dynamic performance is met.

[0074] This utility model also provides an electric motor, including the rotor structure described above.

[0075] The rotor core of this utility model is made of stacked silicon steel sheets. The portion of the silicon steel sheets excluding the magnet placement area has evenly distributed through holes to reduce the weight of the stacked rotor core. These through holes also facilitate rotor dynamic balance. The magnetic slots are arranged according to the motor's electromagnetic design. This rotor core can be achieved using a mature high-speed silicon steel sheet punching press and molds for punching and stacking. The magnets are prefabricated, with their cross-sections prefabricated according to the motor's electromagnetic design. The magnets are then assembled into the rotor core. The first groove at the core assembly position communicates with the impeller assembly, allowing cooling air to flow through a designed channel as the motor rotates. The impeller assembly is integrally die-cast. The main body 8 has an interference-fit mounting hole with the rotor shaft. After the main body 8 is assembled onto the shaft 3, the impeller assemblies 2 on both sides achieve one-sided air compression and one-sided air extraction, ensuring efficient cooling air flow. The impeller assemblies 2 are press-fitted together using a press. The entire machine has a simple, compact, modular design and assembly, making processing convenient. Fully automated production is possible.

[0076] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0077] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model. The above description is only a preferred embodiment of this utility model. 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 this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A rotor structure, characterized by: include: A rotor core (1) is provided with a magnetic steel groove (7) and a through hole (4). The through hole (4) and the magnetic steel groove (7) are arranged at radial intervals along the rotor core (1). A plurality of first grooves (5) are provided on the inner wall of the magnetic steel groove (7). Along the axial direction of the rotor core (1), the magnetic steel groove (7), the first grooves (5) and the through hole (4) penetrate the rotor core (1). An impeller assembly (2) is provided at the end of the rotor core (1). The impeller assembly (2) is used to transport airflow to the first grooves (5) and the through hole (4).

2. The rotor structure of claim 1, wherein: A magnet (6) is provided in the magnet groove (7). The magnet (6) and the first groove (5) enclose a first channel. The impeller assembly (2) is provided at both ends of the rotor core (1). The rotor core (1) and the impeller assembly (2) are sleeved on the rotating shaft (3). One impeller assembly (2) is used to deliver airflow into the first channel and the through hole (4). The other impeller assembly (2) is used to extract the airflow from the first channel and the through hole (4).

3. The rotor structure of claim 1, wherein: Along the circumference of the rotor core (1), the through holes (4) are arranged at intervals, and the through holes (4) are arranged in a one-to-one correspondence with the magnet slots (7); the first groove (5) is located on the inner wall of the magnet slot (7) near the through hole (4).

4. The rotor structure of claim 1, wherein: The impeller assembly (2) includes a main body (8), which has a cavity (9). The cavity (9) includes a bottom plate (10) and a panel (11). The panel (11) has an opening that communicates with the cavity. The bottom plate (10) has a second groove (12) that penetrates the bottom plate (10) and communicates with the cavity (9). A plurality of impellers (13) are disposed in the cavity (9).

5. The rotor structure of claim 4, wherein: The base plate (10) abuts against the end face of the rotor core (1). There are multiple second grooves (12), and the multiple second grooves (12) are arranged at intervals along the circumference of the main body (8). The second grooves (12) are connected to the first groove (5) and the through hole (4).

6. The rotor structure of claim 4, wherein: There is a first gap between the panel (11) and the rotating shaft (3), the gap forming the opening, and there is a second gap between the impeller (13) and the rotating shaft (3), the width of the first gap being greater than the width of the second gap.

7. The rotor structure of claim 4, wherein: The impeller (13) is disposed on the base plate (10), and is arc-shaped along the radial direction of the main body (8). The impeller (13) extends along the rotation direction of the shaft (3).

8. The rotor structure of claim 4, wherein: With the cross-section of the rotor core (1) as the projection plane, the second groove (12) is U-shaped. The second groove (12) has a first section, a second section and a third section. The second section is located between the first section and the third section. The second section is arranged opposite to the first groove (5). The first section and the third section are arranged opposite to the through hole (4).

9. The rotor structure of claim 4, wherein: One end of the impeller (13) is arranged close to the second groove (12), and the other end of the impeller (13) is arranged close to the rotating shaft (3). One end of the impeller (13) is straight, and the first segment and the third segment are arranged opposite to one end of the impeller (13).

10. An electric machine characterized by The rotor structure includes any one of claims 1 to 9.

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