Rotor construction, electric machine and centrifuge

Abstract

The application provides a rotor structure, a motor and a centrifugal machine, wherein the rotor structure comprises a first shaft, a second shaft and a magnetic steel assembly, one end of the magnetic steel assembly is connected with the first shaft, the other end of the magnetic steel assembly is connected with the second shaft, the first shaft and the second shaft are provided with flow-through grooves, air outside the rotor structure can enter the magnetic steel assembly through the flow-through grooves on the first shaft, flow through the magnetic steel assembly, exchange heat with the magnetic steel assembly, and then be discharged through the flow-through grooves on the second shaft. The defect that the magnetic steel in the rotor is difficult to dissipate heat and causes demagnetization of the rotor during operation of the motor in the prior art can be overcome.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a rotor structure, a motor, and a centrifuge. Background Technology

[0002] High-speed permanent magnet synchronous motors have advantages such as small size, high power density, and high motor efficiency, and are widely used in the centrifuge field; small-power ultra-high-speed centrifuges generally use a combined rotor, see [link to relevant documentation]. Figure 1 As shown, the annular or circular magnet 1 serves as the rotor magnetic field, the first shaft 4 and the second shaft 2 act as bearing supports, and a high-strength sheath 3 is fitted onto the outer circle of the magnet and connected to the first shaft 4 and the second shaft 2 to form a combined shaft rotor. In the existing combined rotor, when the rotor sheath 3 is hot-fitted, internal "air trapping" is likely to occur. That is, when the sheath 3 is hot-fitted, the internal gas is not easy to be discharged, which causes the rotor axial dimension to be unstable, making the motor run uneven and increasing the rotor axial movement. When the motor is running, the magnet 1 inside the rotor has difficulty in heat dissipation, which causes the rotor to demagnetize at risk. Summary of the Invention

[0003] Therefore, the present invention provides a rotor structure, a motor, and a centrifuge that can overcome the defect in the prior art where the magnets inside the rotor have difficulty dissipating heat during motor operation, resulting in rotor demagnetization.

[0004] To address the above problems, the present invention provides a rotor structure comprising:

[0005] It includes: a first shaft, a second shaft, and a magnet assembly. One end of the magnet assembly is connected to the first shaft, and the other end is connected to the second shaft. The first shaft and the second shaft are provided with flow grooves. Air outside the rotor structure can enter the magnet assembly through the flow groove on the first shaft, flow through the magnet assembly and exchange heat with the magnet assembly, and then be discharged through the flow groove on the second shaft.

[0006] In some embodiments, the rotor structure further includes a sheath fitted over the magnet assembly located between the first shaft and the second shaft, with at least a portion of the first shaft and at least a portion of the second shaft extending into the sheath and at least a portion of the first shaft and at least a portion of the second shaft engaging with the sheath, and at least a portion of the flow groove on the first shaft and at least a portion of the flow groove on the second shaft located outside the sheath.

[0007] In some embodiments, the flow groove includes a first groove, a second groove, and a third groove. One end of the second groove is connected to the first groove, and the other end is connected to the third groove. The first groove and the second groove are provided on the outer peripheral wall of the first shaft and the outer peripheral wall of the second shaft. The second groove is arranged along the axial direction of the first shaft. The third groove is provided on the end face of the first shaft facing the magnet assembly and the end face of the second shaft facing the magnet assembly.

[0008] In some embodiments, the first shaft includes a first segment and a second segment, one end of the second segment is connected to the first segment, and the other end is connected to the magnet assembly. The diameter of the second segment is smaller than the diameter of the first segment. Along the circumference of the first shaft, the second segment is provided with the first groove, which is located on the second segment near the first segment relative to the magnet assembly. The first groove and the second groove are connected.

[0009] In some embodiments, the second shaft includes a third segment and a fourth segment, one end of the third segment is connected to the fourth segment, and the other end is connected to the magnet assembly. The diameter of the third segment is smaller than the diameter of the fourth segment. Along the circumference of the second shaft, the third segment is provided with a first groove. The first groove is located on the third segment near the fourth segment relative to the magnet assembly. The first groove communicates with a second groove on the second shaft.

[0010] In some embodiments, a fourth groove is provided on the end face of the first shaft facing the magnet assembly and the end face of the second shaft facing the magnet assembly. The first shaft and the second shaft are arranged with the same central axis. The center of the fourth groove is located on the central axis of the first shaft. One end of the third groove is connected to the second groove, and the other end is connected to the fourth groove.

[0011] In some embodiments, the magnet assembly includes a magnet body that is cylindrical, and a first through hole is provided on the end face of the magnet body facing the first shaft along the central axis direction. One end of the first through hole is connected to a flow groove on the first shaft, and the other end is connected to a flow groove on the second shaft.

[0012] In some embodiments, the magnet assembly includes a third shaft and a magnet body. The magnet body is annular and is sleeved on the third shaft. Along the axial direction of the third shaft, a fifth groove is provided on the outer peripheral wall of the third shaft. One end of the fifth groove is connected to a flow groove on the first shaft, and the other end is connected to a flow groove on the second shaft.

[0013] In some embodiments, a second through hole is provided on the end face of the third shaft facing the first shaft along the centerline direction of the third shaft. One end of the second through hole is connected to a flow groove on the first shaft, and the other end is connected to a flow groove on the second shaft.

[0014] The present invention also provides an electric motor comprising the rotor structure described in any of the preceding claims.

[0015] The present invention also provides a centrifuge that includes the motor described above.

[0016] This invention provides a rotor structure, a motor, and a centrifuge. Flow grooves are provided on the first and second shafts. Air outside the rotor structure can enter the magnet assembly through the flow groove on the first shaft and exit through the flow groove on the second shaft, thereby forming a gas circulation between the outside and inside of the rotor structure. The flow grooves can also exchange heat between the first and second shafts. The gas flows through the magnet assembly and exchanges heat with it, which can cool the first shaft, the magnet assembly, and the second shaft. This can effectively reduce the temperature of the magnets inside the rotor and reduce the risk of magnet demagnetization. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the rotor structure in the prior art;

[0018] Figure 2 This is a schematic diagram of the rotor structure provided in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of the first shaft in the rotor structure provided in an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the second shaft in the rotor structure provided in an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the structure of the second shaft or the end face of the second shaft facing the third shaft in the rotor structure provided in the embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of the sheath in the rotor structure provided in an embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of the third shaft in the rotor structure provided in an embodiment of the present invention;

[0024] Figure 8 A schematic cross-sectional view of the third shaft in the rotor structure provided in an embodiment of the present invention;

[0025] Figure 9 This is a schematic diagram of the cooling gas flow direction of the rotor structure provided in an embodiment of the present invention;

[0026] Figure 10 This is a schematic diagram of the third shaft in a rotor structure provided in another embodiment of the present invention;

[0027] Figure 11 A schematic cross-sectional view of the third shaft in a rotor structure provided for another embodiment of the present invention;

[0028] Figure 12 A schematic diagram of the cooling gas flow direction of the rotor structure provided in another embodiment of the present invention.

[0029] The reference numerals in the attached figures are as follows:

[0030] 1. Magnet body; 2. Second shaft; 3. Sheath; 4. First shaft; 5. Third shaft; 6. Magnet assembly; 7. First section; 8. Second section; 9. Third section; 10. Fourth section; 11. First groove; 12. Second groove; 13. Third groove; 14. Fourth groove; 15. First through hole; 16. Fifth groove; 17. Second through hole. Detailed Implementation

[0031] See also Figures 2 to 12 As shown in the embodiment of the present invention, a rotor structure is provided, comprising: a first shaft 4, a second shaft 2, and a magnet assembly 6. One end of the magnet assembly 6 is connected to the first shaft 4, and the other end is connected to the second shaft 2. Flow grooves are provided on the first shaft 4 and the second shaft 2. Air outside the rotor structure can enter the magnet assembly 6 through the flow grooves on the first shaft 4, flow through the magnet assembly 6 and exchange heat with it, and then be discharged through the flow grooves on the second shaft 2. In this technical solution, the flow grooves on the first shaft 4 and the second shaft 2 allow air outside the rotor structure to enter the magnet assembly 6 through the flow grooves on the first shaft 4 and be discharged through the flow grooves on the second shaft 2, thereby forming a gas circulation between the outside and inside of the rotor structure. The flow grooves also facilitate heat exchange between the first shaft 4 and the second shaft 2. The gas flowing through the magnet assembly 6 and exchanging heat with it can cool the first shaft 4, the magnet assembly 6, and the second shaft 2, effectively reducing the temperature of the magnets inside the rotor and minimizing the risk of magnet demagnetization. Preferably, the flow channel can be disposed on the end face of the first shaft 4 facing the magnet assembly 6 and the end face of the second shaft 2 facing the magnet assembly 6. When the first shaft 4 and the second shaft 2 are connected to the magnet assembly 6, a flow channel can be formed on the end face of the first shaft 4 facing the magnet assembly 6 and the end face of the second shaft 2 facing the magnet assembly 6, so that air outside the rotor structure can enter the magnet assembly 6 and perform heat exchange and cooling inside the magnet assembly 6. Compared with the existing integrated rotor structure, the rotor structure of the present invention has the characteristics of low cost, good versatility, good maintainability and low maintenance cost. The rotor structure of the present invention greatly reduces the assembly difficulty of high-speed combined rotor shaft and ensures the stability and consistency of axial dimensions.

[0032] This invention discloses a rotor structure in which multiple second grooves 12 are formed on the cylindrical surface connecting the first shaft 4, the second shaft 2, and the alloy sheath 3. These second grooves 12 are similar to splines. The multiple second grooves 12 are connected to third grooves 13 on either the first shaft 4 or the second shaft 2. These third grooves 13 are machined relief grooves. Simultaneously, an equal number of third grooves 13 on the end faces of the first shaft 4 or the second shaft 2 are connected. The third grooves 13 can be of equal width, radial fan-shaped grooves, etc. The third grooves 13 lead to a converging fourth groove 14 at the center of the end face, which connects the ventilation grooves. The rotor is connected to cooling holes for the magnets, allowing external refrigerant or airflow to enter the rotor. Air enters at the connection between the first shaft 4 and the rotor sleeve 3, and exits at the connection between the second shaft 2 and the rotor sleeve, or vice versa, creating an airflow circulation that cools the first shaft 4 and the magnets, significantly reducing rotor overheating and the risk of magnet demagnetization in high-speed motors. During rotor manufacturing, the assembly of the sleeve 3 with the first shaft 4 and the second shaft 2 uses a heat-fitting process. If hot air cannot be effectively expelled, residual gas will remain between the first shaft 4 / 2 and the magnets, and between the magnets and the rotor sleeve 3. Firstly, this residual gas will increase the axial dimension of the rotor after heat fitting, affecting its stability and potentially causing misalignment of the stator and rotor linkage magnetic fields, increasing magnetic leakage and reducing motor efficiency. Secondly, this trapped gas condenses into water, causing oxidation of the magnet surface and reducing magnetic properties. This invention effectively eliminates the gas trapped inside the rotor during heat fitting, improving production stability and rotor quality. By creating specific slots on the first shaft 4 and second shaft 2 of the high-speed motor combined shaft rotor, and simultaneously opening holes in the center of the solid or annular magnets, external cooling gas or refrigerant can enter the rotor to cool the rotor magnets, significantly reducing the risk of magnet demagnetization due to rotor overheating. Furthermore, because the depth of the venting slots is designed to be less than or equal to the depth of the relief slots, adding venting slots to the front and rear short shafts does not reduce the strength of the first shaft 4, second shaft 2, or the high-speed rotor. In addition, this invention simplifies rotor manufacturing and improves the stability of the rotor's axial dimensions during the heat-fitting installation of the alloy sheath 3. Due to the slotting, the hot gas trapped inside the rotor during heat-fitting can be discharged through the venting slots. This significantly reduces potential rotor problems and improves rotor reliability.

[0033] In some embodiments, the rotor structure further includes a sheath 3, which is sleeved on the magnet assembly 6. The magnet assembly 6 is located between the first shaft 4 and the second shaft 2. At least a portion of the first shaft 4 and at least a portion of the second shaft 2 extend into the sheath 3, and at least a portion of the first shaft 4 and at least a portion of the second shaft 2 are sleeved with the sheath 3. A flow groove on the first shaft 4 and at least a portion of a flow groove on the second shaft 2 are located outside the sheath 3. See also [link to technical solution]. Figure 6As shown, the sleeve 3 is cylindrical and connects the first shaft 4, the magnet assembly 6, and the second shaft 2 into one unit. The sleeve 3 assembles the first shaft 4, the magnet assembly 6, and the second shaft 2 using a heat-fitting process. If the hot gas cannot be effectively discharged during this process, residual gas will remain between the first shaft 4, the second shaft 2, and the magnet assembly 6, and between the first shaft 4, the magnet assembly 6, the second shaft 2, and the rotor sleeve 3. Firstly, this residual gas will increase the axial dimension of the rotor after heat fitting, affecting the stability of the rotor's axial dimension. In severe cases, it may even cause misalignment of the stator and rotor linkage magnetic fields, increasing magnetic leakage and reducing motor efficiency. Secondly, this gas trapped inside the rotor will condense into water, causing oxidation of the magnet surface and reducing magnetic properties. The rotor structure of this invention, by having at least a portion of the flow grooves on the first shaft 4 and the second shaft 2 located outside the sleeve 3, can effectively remove the gas trapped inside the rotor during heat fitting, improving production stability and rotor quality.

[0034] In some embodiments, the flow channel includes a first groove 11, a second groove 12, and a third groove 13. One end of the second groove 12 is connected to the first groove 11, and the other end is connected to the third groove 13. The first groove 11 and the second groove 12 are provided on the outer peripheral wall of the first shaft 4 and the outer peripheral wall of the second shaft 2. The second groove 12 is arranged along the axial direction of the first shaft 4. The third groove 13 is provided on the end face of the first shaft 4 facing the magnet assembly 6 and the end face of the second shaft 2 facing the magnet assembly 6. In this technical solution, the flow channel is composed of a first groove 11, a second groove 12, and a third groove 13. The first groove 11 and the second groove 12 are provided on the outer peripheral wall of the first shaft 4 and the outer peripheral wall of the second shaft 2. The second groove 12 is arranged along the axial direction of the first shaft 4. The third groove 13 is provided on the end face of the first shaft 4 facing the magnet assembly 6 and the end face of the second shaft 2 facing the magnet assembly 6. This allows air outside the rotor structure to flow into the interior of the rotor structure through the first groove 11, the second groove 12, and the third groove 13 to exchange heat and cool the inside of the magnet assembly 6. Preferably, the first groove 11 also serves as a tool relief groove, and the depth of the first groove 11 is not less than the depth of the second groove. Preferably, multiple second grooves 12 can be provided along the circumference of the first shaft 4 or the second shaft 2. By using multiple second grooves 12, the inflow efficiency of air outside the rotor structure is increased, thereby improving the cooling efficiency.

[0035] In some implementations, see Figure 3As shown, the first shaft 4 includes a first segment 7 and a second segment 8. One end of the second segment 8 is connected to the first segment 7, and the other end is connected to the magnet assembly 6. The diameter of the second segment 8 is smaller than the diameter of the first segment 7. Along the circumference of the first shaft 4, the second segment 8 is provided with the first groove 11. The first groove 11 is located on the second segment 8 near the first segment 7 relative to the magnet assembly 6. The first groove 11 is connected to the second groove 12. In this technical solution, a first groove 11 is provided on the second segment 8. When the sheath 3 is included, the first groove 11 is located outside the sheath 3. The first groove 11 is connected to the second groove 12. Air outside the rotor structure is transported to the second groove 12 through the first groove 11 to cool the first shaft 4, the magnet assembly 6, and the second shaft 2. In addition, the sleeve length between the first shaft 4 and the sheath 3 can be guaranteed, which effectively improves the strength of the rotor. Specifically, the diameter of the second segment 8 is the same as the diameter of the magnet assembly 6, and the thickness of the sheath 3 plus the diameter of the magnet assembly 6 is the same as the diameter of the first segment 7, which ensures that the rotor structure is easy to install and disassemble.

[0036] In some implementations, see Figure 4 As shown, the second shaft 2 includes a third segment 9 and a fourth segment 10. One end of the third segment 9 is connected to the fourth segment 10, and the other end is connected to the magnet assembly 6. The diameter of the third segment 9 is smaller than the diameter of the fourth segment 10. Along the circumference of the second shaft 2, the third segment 9 is provided with a first groove 11. The first groove 11 is located on the third segment 9 near the fourth segment 10 relative to the magnet assembly 6. The first groove 11 is connected to a second groove 12 on the second shaft 2. In this technical solution, a first groove 11 is provided on the third segment 9. When the sheath 3 is included, the first groove 11 is located outside the sheath 3. The first groove 11 is connected to the second groove 12. The air after heat exchange of the magnet assembly 6 is discharged through the first groove 11 to complete the cooling of the first shaft 4, the magnet assembly 6 and the second shaft 2. In addition, it can also ensure the sleeve length between the second shaft 2 and the sheath 3, effectively improving the strength of the rotor. Specifically, the diameter of the third segment 9 is the same as the diameter of the magnet assembly 6, and the thickness of the sheath 3 plus the diameter of the magnet assembly 6 is the same as the diameter of the fourth segment 10, ensuring that the rotor structure is easy to install and disassemble.

[0037] In some implementations, see Figure 5As shown, a fourth groove 14 is provided on the end face of the first shaft 4 facing the magnet assembly 6 and the end face of the second shaft 2 facing the magnet assembly 6. The first shaft 4 and the second shaft 2 are arranged with the same central axis. The center of the fourth groove 14 is located on the central axis of the first shaft 4. One end of the third groove 13 is connected to the second groove 12, and the other end is connected to the fourth groove 14. In this technical solution, air from the second groove 12 is transported to the fourth groove 14 of the first shaft 4 via the third groove 13. The air converges in the fourth groove 14 of the first shaft 4 and then flows through the magnet assembly 6 to exchange heat with the magnet assembly 6. Alternatively, the air after heat exchange in the magnet assembly 6 is converged into the fourth groove 14 of the second shaft 2. The fourth groove 14 can also cool the interior of the first shaft 4 or the second shaft 2. When multiple second grooves 12 are provided along the circumference of the first shaft 4 or the second shaft 2, multiple third grooves 13 can be correspondingly provided on the end face of the first shaft 4 facing the magnet assembly 6 and the end face of the second shaft 2 facing the magnet assembly 6. The third grooves 13 correspond one-to-one with the second grooves 12, increasing the flow area of ​​external air in the rotor structure and improving cooling efficiency. Preferably, the width of one end of the third groove 13 is greater than the width of the other end. When there are multiple third grooves 13, they can be arranged radially to increase the number of third grooves 13.

[0038] In some implementations, see Figure 7 , Figure 8 and Figure 8As shown, the magnet assembly 6 includes a magnet body 1, which is cylindrical. A first through hole 15 is provided on the end face of the magnet body 1 facing the first shaft 4 along the central axis of the magnet body 1. One end of the first through hole 15 is connected to a flow groove on the first shaft 4, and the other end is connected to a flow groove on the second shaft 2. In this technical solution, the rotor structure of the present invention is a rotor-coreless combined shaft. Air from the flow groove on the first shaft 4 is introduced into the first through hole 15 to exchange heat and cool the interior of the magnet body 1, greatly reducing the risk of thermal demagnetization of the magnet. Furthermore, it has strong anti-demagnetization capabilities, maximally preserving the original combined shaft rotor structure characteristics and ensuring that the strength and stiffness of the combined shaft remain unchanged. This invention is mainly applicable to high-speed permanent magnet synchronous motors with a first shaft 4 and a second shaft 2 combined, using circular or annular magnets as the rotor magnetic field. Shallow grooves are created at specific locations on the first shaft 4 and second shaft 2 of the rotor, and an axial hole is opened at the center of the circular magnet body 1, allowing refrigerant to enter the high-speed rotor and cool the two end faces and center of the magnet. This significantly reduces the risk of thermal demagnetization of the magnet, which would cause motor failure, without reducing the overall strength of the rotor. A fourth groove 14 is designed on the end face of the first shaft 4 and second shaft 2 that contacts the magnet. External gas flows through multiple radial third grooves 13 and converges into the fourth groove 14 at the center of the end face of the first shaft 4 and second shaft 2. The depth of the fourth groove 14 is the same as the depth of the third grooves 13 on the end face. The fourth groove 14 directly connects to the first through hole 15 of the magnet. The airflow reaches the fourth groove 14 at the other end through the central hole of the magnet and flows out of the rotor along the multiple radial third grooves 13.

[0039] In some implementations, see Figure 10 and Figure 12As shown, the magnet assembly 6 includes a third shaft 5 and a magnet body 1. The magnet body 1 is annular and is sleeved on the third shaft 5. Along the axial direction of the third shaft 5, a fifth groove 16 is provided on the outer peripheral wall of the third shaft 5. One end of the fifth groove 16 is connected to the flow groove on the first shaft 4, and the other end is connected to the flow groove on the second shaft 2. In this technical solution, the magnet body 1 is annular and is sleeved on the third shaft 5, reducing the cost of the magnet assembly 6. Along the axial direction of the third shaft 5, a fifth groove 16 is provided on the outer peripheral wall of the third shaft 5. Through the fifth groove 16, heat exchange and cooling can be performed on the inner wall of the magnet body 1, reducing the risk of thermal demagnetization of the magnet. When the flow channel is composed of a first groove 11, a second groove 12, and a third groove 13, the first groove 11 and the second groove 12 are provided on the outer peripheral wall of the first shaft 4 and the outer peripheral wall of the second shaft 2. The second groove 12 is arranged along the axial direction of the first shaft 4. When multiple second grooves 12 are set along the circumference of the first shaft 4 or the second shaft 2, multiple fifth grooves 16 can also be set along the circumference of the third shaft 5. The fifth groove 16 and the second groove 12 are arranged in a one-to-one correspondence, increasing the heat exchange area of ​​the inner wall of the magnet body 1 and improving the cooling efficiency. When the magnet assembly 6 includes a third shaft 5 and a magnet body 1, tangential positioning is performed during the heat-fitting process. This involves using a specific process to ensure that the cooling grooves on the outer circumference of the first shaft 4, the second shaft 2, and the magnet assembly 6 are aligned in a straight line. This creates multiple cooling paths, ensuring optimal cooling performance. If this flow channel is not provided on the outer circumference, then tangential positioning is not required during heat-fitting, similar to a solid magnet.

[0040] In some implementations, see Figure 11As shown, along the centerline of the third shaft 5, a second through hole 17 is provided on the end face of the third shaft 5 facing the first shaft 4. One end of the second through hole 17 is connected to a flow groove on the first shaft 4, and the other end is connected to a flow groove on the second shaft 2. In this technical solution, heat exchange and cooling of the interior of the third shaft 5 are achieved through the second through hole 17. When the motor runs at high speed, the third shaft 5 will also generate temperature, which will be transferred to the magnet 1. By cooling the third shaft 5, the heating rate of the magnet 1 can be slowed down. When the temperature of the magnet 1 is too high, heat exchange can also be performed on the magnet 1. The rotor structure adopts a magnet body 1 + a third shaft 5. The third shaft 5 not only has a second through hole 17 at its center, but also has a fifth groove 16 on its cylindrical surface, the same number as the front and rear short shafts. After assembly, the airflow grooves on the cylindrical surfaces of the first shaft 4, second shaft 2, and third shaft 5 are connected, allowing airflow to pass through. Simultaneously, some airflow passes through the radial third groove 13 on the end face, collects in the fourth groove 14, flows into the second through hole 17 of the third shaft 5, and then flows out from the other end. This achieves a dual-line cooling rotor. In terms of manufacturing, since the alloy sheath 3 must be assembled using a hot-fitting process, its size increases after heating, and returns to its original size after cooling. During the hot-fitting process, the end faces of the first shaft 4 and second shaft 2 must be in close contact with the magnet assembly 6. Therefore, there will inevitably be a gap between the alloy sheath 3 and the stepped surfaces of the first shaft 4 and second shaft 2, through which cooling airflow can enter the rotor interior. The depth of the second groove 12 is less than or equal to the depth of the first groove 11, i.e., the depth of the stepped relief groove. The mechanical strength of the motor rotor is almost unaffected and therefore does not require calculation. If the depth of the second groove 12 is greater than the depth of the machining relief groove, and it also serves as an annular venting groove, it may affect the strength of the first shaft 4 and the second shaft 2. The mechanical strength of the combined shaft rotor should be calculated using simulation or analytical methods. Since high-speed permanent magnet synchronous motors require rare earth magnets, using annular magnets + medium and short shafts can save expensive rare earth materials and reduce costs. In summary, the front and rear short shaft structure of this invention has the obvious characteristics of a combined shaft rotor. This invention makes full use of the characteristics of the first shaft 4 and the second shaft 2. For example, the machining relief groove is used as the annular first groove 11 to connect the second groove 12 evenly distributed on the cylindrical surface; the gap naturally formed during the heat fitting of the alloy sheath 2 is used as the air inlet and outlet of the combined shaft rotor, thus preserving the original structural characteristics of the combined shaft rotor to the maximum extent and ensuring that the strength and rigidity of the combined shaft remain unchanged. The third groove 13 on the end face of the first shaft 4 and the second shaft 2 has two structures: equal width groove and fan-shaped groove; in the application examples of the present invention, there are solid circular magnet combined shaft structures and hollow annular magnet combined shaft structures. In the annular magnet structure combined shaft rotor, since the cylindrical surfaces of the first shaft 4 and the second shaft 2 can also open air grooves, theoretically, the cooling effect should be better than that of the circular magnet structure combined shaft rotor.

[0041] The present invention also provides an electric motor, including the rotor structure described above.

[0042] The present invention also provides a centrifuge, including the motor described above.

[0043] The above description is merely a preferred embodiment of the present invention and is 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 description is only a preferred embodiment 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 rotor structure, characterized in that: include: The rotor consists of a first shaft (4), a second shaft (2), and a magnet assembly (6). One end of the magnet assembly (6) is connected to the first shaft (4), and the other end is connected to the second shaft (2). Flow grooves are provided on the first shaft (4) and the second shaft (2). Air outside the rotor structure can enter the magnet assembly (6) through the flow groove on the first shaft (4), flow through the magnet assembly (6), exchange heat with the magnet assembly (6), and then be discharged through the flow groove on the second shaft (2). The rotor structure further includes a sheath (3), which is fitted onto the magnet assembly (6). The magnet assembly (6) is located between the first shaft (4) and the second shaft (2). At least a portion of the first shaft (4) and at least a portion of the second shaft (2) extend into the sheath (3), and at least a portion of the first shaft (4) and at least a portion of the second shaft (2) are fitted with the sheath (3). At least a portion of the flow groove on the first shaft (4) and at least a portion of the flow groove on the second shaft (2) are located outside the sheath (3). The first shaft (4) includes a first section (7) and a second section (8). One end of the second section (8) is connected to the first section (7), and the other end is connected to the magnet assembly (6). The diameter of the second section (8) is smaller than the diameter of the first section (7). The second shaft (2) includes a third section (9) and a fourth section (10). One end of the third section (9) is connected to the fourth section (10), and the other end is connected to the magnet assembly (6). The diameter of the third section (9) is smaller than the diameter of the fourth section (10). The diameter of segment (10), the sheath (3) is sleeved on the third segment (9), the magnet assembly (6) and the second segment (8), and there is a gap between one end of the sheath (3) and the first segment (7) and between the other end of the sheath (3) and the fourth segment (10); the magnet assembly (6) includes a third shaft (5) and a magnet body (1), the magnet body (1) is annular, the magnet body (1) is sleeved on the third shaft (5), along the axial direction of the third shaft (5), the third A fifth groove (16) is provided on the outer peripheral wall of the shaft (5). One end of the fifth groove (16) is connected to the flow groove on the first shaft (4), and the other end is connected to the flow groove on the second shaft (2). Along the centerline of the third shaft (5), a second through hole (17) is provided on the end face of the third shaft (5) facing the first shaft (4). One end of the second through hole (17) is connected to the flow groove on the first shaft (4), and the other end is connected to the flow groove on the second shaft (2).

2. The rotor structure according to claim 1, characterized in that: The flow channel includes a first groove (11), a second groove (12) and a third groove (13). One end of the second groove (12) is connected to the first groove (11) and the other end is connected to the third groove (13). The first groove (11) and the second groove (12) are provided on the outer peripheral wall of the first shaft (4) and the outer peripheral wall of the second shaft (2). The second groove (12) is arranged along the axial direction of the first shaft (4). The third groove (13) is provided on the end face of the first shaft (4) facing the magnet assembly (6) and the end face of the second shaft (2) facing the magnet assembly (6).

3. The rotor structure according to claim 2, characterized in that: Along the circumference of the first axis (4), the second segment (8) is provided with the first groove (11), the first groove (11) is located on the second segment (8) near the first segment (7) relative to the magnet assembly (6), and the first groove (11) is connected to the second groove (12).

4. The rotor structure according to claim 2, characterized in that: Along the circumference of the second axis (2), the first groove (11) is provided on the third segment (9), the first groove (11) is located on the third segment (9) near the fourth segment (10) relative to the magnet assembly (6), and the first groove (11) is connected to the second groove (12) on the second axis (2).

5. The rotor structure according to claim 2, characterized in that: A fourth groove (14) is provided on the end face of the first shaft (4) facing the magnet assembly (6) and the end face of the second shaft (2) facing the magnet assembly (6). The first shaft (4) and the second shaft (2) are arranged with the same central axis. The center of the fourth groove (14) is located on the central axis of the first shaft (4). One end of the third groove (13) is connected to the second groove (12), and the other end is connected to the fourth groove (14).

6. An electric motor, characterized in that, The rotor structure includes any one of claims 1-5.

7. A centrifuge, characterized in that, Includes the motor described in claim 6.

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