A rotor structure, electric machine, compressor

Abstract

The application provides a rotor structure, a motor and a compressor, wherein the rotor structure comprises a sheath, a permanent magnet, two end shafts, a first ring and a second ring are sleeved in the sheath, the permanent magnet is located between the two end shafts, one end shaft is at least partially sleeved with the first ring, and the other end shaft is at least partially sleeved with the second ring; a first short shaft is sleeved in the first ring, one end shaft is located between the first short shaft and the permanent magnet; a second short shaft is sleeved in the second ring, and the other end shaft is located between the second short shaft and the permanent magnet; along the axial direction of the permanent magnet, a first gap is formed between the first short shaft and one end shaft and between the second short shaft and the other end shaft; the first ring and the second ring are made of a material with a negative expansion coefficient; according to the application, the technical problem that the shaft material is elongated by heat in the prior art when a high-speed motor is in rated operation, and the impeller and the volute are impacted and damaged can be solved.

Description

Technical Field

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

[0002] High-speed motors have extremely broad application prospects due to their small size, high power density, high transmission efficiency, and high reliability, in fields such as aerospace, national defense, new energy industry, and household appliances. Especially in high-speed load applications such as electric spindles, micro gas turbines, flywheel energy storage, and turbomachinery, the high-speed development of motor systems can achieve direct drive, eliminating the need for speed changers and significantly reducing equipment size and maintenance costs. However, this also places higher demands on the design of the motor itself. Furthermore, the high speed and high electromagnetic frequency of high-speed motors lead to a dramatic increase in mechanical and electrical losses, resulting in increased heat generation. The rated operating temperature of high-speed motors is also significantly higher than that of ordinary motors, which is an important factor that the industry needs to consider in the design of high-speed motors.

[0003] In the refrigeration field, centrifugal compressors have garnered significant attention due to their ability to adapt well to high-altitude, long-distance operating scenarios. However, the refrigeration industry often requires compressors with low flow rates and high pressure ratios, which necessitates small impeller outer diameters and high rotational speeds. Simultaneously, high compressor energy efficiency demands require even smaller blade tip clearances. The high temperatures generated by high-speed motors during rated operation cause significant thermal deformation of the shaft material, resulting in excessive axial elongation of the shaft. This leads to both drastic variations in compressor energy efficiency and an excessively small blade tip clearance under rated operating conditions, posing a risk of impact damage between the impeller and the volute.

[0004] Because existing high-speed motors suffer from thermal expansion of the shaft material during rated operation, resulting in impact damage between the impeller and the volute, this invention researches and designs a rotor structure, motor, and compressor. Summary of the Invention

[0005] Therefore, the present invention provides a rotor structure, a motor, and a compressor that can solve the technical problem in the prior art where the shaft material elongates due to heat during the rated operation of a high-speed motor, resulting in impact damage between the impeller and the volute.

[0006] To address the aforementioned problems, the present invention provides a rotor structure comprising: a sheath, wherein a permanent magnet, two end shafts, a first ring sleeve, and a second ring sleeve are disposed within the sheath; the permanent magnet is located between the two end shafts; one end shaft is at least partially sleeved with the first ring sleeve, and the other end shaft is at least partially sleeved with the second ring sleeve; a first short shaft is disposed within the first ring sleeve; one end shaft is located between the first short shaft and the permanent magnet; a second short shaft is disposed within the second ring sleeve; and the other end shaft is located between the second short shaft and the permanent magnet; along the axial direction of the permanent magnet, a first gap exists between the first short shaft and one end shaft, and between the second short shaft and the other end shaft; the first ring sleeve and the second ring sleeve are made of a material with a negative coefficient of thermal expansion.

[0007] In some embodiments, the first short shaft includes a first mating section, a first sealing section, a first cold assembly section, and a first assembly section connected in sequence. The outer diameters of the first mating section, the first cold assembly section, and the first assembly section are smaller than the outer diameter of the first sealing section. The first cold assembly section and the first assembly section are at least partially sleeved with the first ring sleeve. The first assembly section has a first gap with one of the end shafts.

[0008] In some embodiments, the rotor structure further includes a thrust plate, the thrust plate comprising a third assembly section and a thrust section, the thrust section being located on the outer peripheral wall of the third assembly section, the third assembly section being at least partially fitted within the sheath, the thrust section being located outside the sheath along the axial direction of the sheath, the portion of the third assembly section within the sheath abutting against the first ring sleeve, and a second gap being present between the thrust section and the sheath; the first cold-assembly section passing through the third assembly section and extending into the first ring sleeve, and the first sealing section abutting against the end of the third assembly section.

[0009] In some embodiments, the first assembly section has a groove at one end facing the end shaft, and the first mating section has a connecting hole at one end away from the first sealing section. The first mating section is connected to the first impeller and the first locking member through the connecting hole.

[0010] In some embodiments, the second short shaft includes a second mating section, a second sealing section, a second cold assembly section, and a second assembly section connected in sequence. The outer diameters of the second mating section, the second cold assembly section, and the second assembly section are smaller than the outer diameter of the second sealing section. The second cold assembly section and the second assembly section are sleeved with the second ring sleeve. The second sealing section is located outside the sheath and the second ring sleeve.

[0011] In some embodiments, the end of the sheath away from the first short axis and the end of the second ring away from the first short axis are located on the same plane, the end of the second sealing section facing the end shaft abuts against the second ring, and the second assembly section has a first gap with the other end shaft.

[0012] In some embodiments, the second assembly section has a fixing groove at one end facing the end shaft, and the second mating section has a mounting hole at one end away from the second sealing section. The second mating section is connected to the second impeller through the mounting hole and the second locking member.

[0013] In some embodiments, the first minor axis and the second minor axis are made of materials with a positive coefficient of thermal expansion.

[0014] The present invention also provides an electric motor comprising the aforementioned rotor structure.

[0015] The present invention also provides a compressor that includes the aforementioned motor.

[0016] The rotor structure, motor, and compressor provided by this invention have the following beneficial effects:

[0017] A first gap exists between the first short shaft and one of the end shafts, and between the second short shaft and the other end shaft. This first gap ensures that when the ring sleeve contracts due to heat, the short shaft has sufficient deformation space along the axis towards the magnet. The first and second ring sleeves are made of materials with a negative coefficient of thermal expansion. The negative expansion ring sleeves will undergo axial contraction under the high-temperature environment of the high-speed motor's rated operation, offsetting the thermal expansion on other shaft sections and significantly reducing the axial thermal expansion of the high-speed rotor assembly, thereby ensuring the relative stability of the compressor blade tip clearance during operation. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below 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 the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the first short shaft in the rotor structure of the present invention;

[0021] Figure 3 This is a schematic diagram of the end shaft in the rotor structure of the present invention;

[0022] Figure 4 This is a schematic diagram of the thrust plate in the rotor structure of the present invention;

[0023] Figure 5 This is a schematic diagram of the second short shaft in the rotor structure of the present invention.

[0024] The attached figures are labeled as follows:

[0025] 1. First locking element; 2. First impeller; 3. First short shaft; 4. Thrust plate; 5. First ring sleeve; 6. End shaft; 7. Sheath; 8. Permanent magnet; 9. Second ring sleeve; 10. Second short shaft; 11. Second impeller; 12. Second locking element; 301. First mating section; 302. First sealing section; 303. First cold assembly section; 304. First assembly section; 1001. Second mating section; 1002. Second sealing section; 1003. Second cold assembly section; 1004. Second assembly section; 601. Sheath mating section; 602. Ring sleeve mating section; 401. Third assembly section; 402. Thrust section. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, 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 invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention 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 invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0028] 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.

[0029] 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 should not be construed as limiting the scope of protection of this invention.

[0030] See also Figure 1-5 As shown, according to an embodiment of the present invention, a rotor structure is provided, comprising: a sheath 7, wherein a permanent magnet 8, two end shafts 6, a first ring sleeve 5, and a second ring sleeve 9 are disposed within the sheath 7, the permanent magnet 8 is located between the two end shafts 6, one end shaft 6 is at least partially sleeved with the first ring sleeve 5, and the other end shaft 6 is at least partially sleeved with the second ring sleeve 9, a first short shaft 3 is disposed within the first ring sleeve 5, one end shaft 6 is located between the first short shaft 3 and the permanent magnet 8, a second short shaft 10 is disposed within the second ring sleeve 9, and the other end shaft 6 is located between the second short shaft 10 and the permanent magnet 8, and a first gap is formed between the first short shaft 3 and one end shaft 6 and between the second short shaft 10 and the other end shaft 6 along the axial direction of the permanent magnet 8, wherein the first ring sleeve 5 and the second ring sleeve 9 are made of a material with a negative coefficient of thermal expansion.

[0031] In this technical solution, a first gap exists between the first short shaft 3 and one of the end shafts 6, and between the second short shaft 10 and the other end shaft 6. This first gap ensures that when the ring sleeve is heated and contracts, the short shaft has sufficient deformation space along the axis towards the magnet. The first ring sleeve 5 and the second ring sleeve 9 are made of a material with a negative expansion coefficient. The ring sleeve with negative expansion will undergo axial contraction under the high temperature environment of the high-speed motor's rated operation, offsetting the thermal expansion on other shaft sections and significantly reducing the axial thermal expansion of the high-speed rotor assembly, thereby ensuring the relative stability of the compressor blade tip clearance during operation.

[0032] In some embodiments, the first short shaft 3 includes a first mating section 301, a first sealing section 302, a first cold assembly section 303, and a first assembly section 304 connected in sequence. The outer diameters of the first mating section 301, the first cold assembly section 303, and the first assembly section 304 are smaller than the outer diameter of the first sealing section 302. The first cold assembly section 303 and the first assembly section 304 are at least partially sleeved with the first ring sleeve 5. The first assembly section 304 has a first gap with one of the end shafts 6.

[0033] In some embodiments, the rotor structure further includes a thrust plate 4, which includes a third assembly section 401 and a thrust section 402. The thrust section 402 is located on the outer peripheral wall of the third assembly section 401. The third assembly section 401 is at least partially fitted into the sheath 7. The thrust section 402 is located outside the sheath 7 along the axial direction of the sheath 7. The portion of the third assembly section 401 located in the sheath 7 abuts against the first ring sleeve 5. A second gap exists between the thrust section 402 and the sheath 7. The first cold assembly section 303 passes through the third assembly section 401 and extends into the first ring sleeve 5. The first sealing section 302 abuts against the end of the third assembly section 401.

[0034] In this technical solution, the thrust plate 4 has a third assembly section 401 and a thrust section 402. The third assembly section 401 is partially disposed inside the sheath 7 and is in an interference fit relationship, with its end face in close contact with the first ring sleeve 5. The thrust section 402 does not contact the sheath 7 in the axial direction, thereby ensuring that the end face of the third assembly section 401 is in close contact with the first ring sleeve.

[0035] The first short shaft 3 has a first mating section 301, a first sealing section 302, a first cold assembly section 303, and a first assembly section 304. The first mating section 301 has the first impeller 2 and locking bolts arranged sequentially outward along the axial direction. The end face of the first sealing section 302 away from the impeller is in close contact with the thrust disc 4, and the outer diameter of the first sealing section 302 forms a dynamic seal with the comb teeth. The outer diameter of the first cold assembly section 303 is the same as the inner diameter of the first ring sleeve 5 and forms an interference fit. During assembly, the first cold assembly section 303 is pre-cooled and shrunk before mating with the first ring sleeve 5. During disassembly, the mating parts are pre-cooled. The first cold assembly section 303 shrinks when cooled, while the first ring sleeve 5 expands when cooled, thereby achieving easy disassembly of the first short shaft 3. Furthermore, when the high-speed rotor assembly is running under rated conditions, the high temperature causes the first short shaft 3 to expand while the first ring sleeve 5 contracts, and the two will become increasingly tightly bound, preventing the first short shaft 3 from separating from the rotor assembly during high-speed operation.

[0036] In some embodiments, the first assembly section 304 has a groove at one end facing the end shaft 6, and the first mating section 301 has a connecting hole at one end away from the first sealing section 302. The first mating section 301 is connected to the first impeller 2 and the first locking member 1 through the connecting hole.

[0037] In this technical solution, the first assembly section 304 is used to fix the first short shaft 3, thereby locking the first impeller 2 through the first locking member 1. The first locking member 1 is a first locking bolt, and the groove of the first assembly section 304 can be of various forms, including but not limited to internal hexagonal and external hexagonal. When locking the impeller with the bolt, the short shaft must be fixed, and the groove is used to fix the first short shaft 3. The groove serves as a clamping position for a wrench or other fixing tool.

[0038] In some embodiments, the second short shaft 10 includes a second mating section 1001, a second sealing section 1002, a second cold assembly section 1003, and a second assembly section 1004 connected in sequence. The outer diameters of the second mating section 1001, the second cold assembly section 1003, and the second assembly section 1004 are smaller than the outer diameter of the second sealing section 1002. The second cold assembly section 1003 and the second assembly section 1004 are sleeved with the second ring sleeve 9. The second sealing section 1002 is located outside the sheath 7 and the second ring sleeve 9.

[0039] In some embodiments, the end of the sheath 7 away from the first short shaft 3 and the end of the second ring sleeve 9 away from the first short shaft 3 are located on the same plane, the end of the second sealing section 1002 facing the end shaft 6 abuts against the second ring sleeve 9, and the second assembly section 1004 has a first gap with the other end shaft 6.

[0040] In this technical solution, the second short shaft 10 has a second mating section 1001, a second sealing section 1002, a second cold assembly section 1003, and a second assembly section 1004. The second mating section 1001 has the second impeller 11 and locking bolts arranged sequentially outward along the axial direction. The outer diameter of the second sealing section 1002 forms a dynamic seal with the upper comb teeth. The outer diameter of the second cold assembly section 1003 is the same as the inner diameter of the second ring sleeve 9, forming an interference fit. During assembly, the second cold assembly section 1003 is pre-cooled and contracted before mating with the second ring sleeve 9. During disassembly, the mating parts are cooled. The second cold assembly section 1003 contracts upon cooling, while the second ring sleeve 9 expands, thus enabling easy disassembly of the second short shaft 10. Furthermore, when the high-speed rotor assembly is running under rated conditions, the high temperature causes the second short shaft 10 to expand while the second ring sleeve 9 contracts, resulting in a tighter fit between the two, preventing the second short shaft 10 from detaching from the rotor assembly during high-speed operation.

[0041] In some embodiments, the second assembly section 1004 has a fixing groove at one end facing the end shaft 6, and the second mating section 1001 has a mounting hole at one end away from the second sealing section 1002. The second mating section 1001 is connected to the second impeller 11 through the mounting hole and the second locking member 12.

[0042] In this technical solution, the second assembly section 1004 is used to fix the second short shaft 10, and the second impeller 11 is locked by the second locking member 12. The second locking member is a second locking bolt, and the fixing groove can be of various forms, including but not limited to internal hexagonal and external hexagonal. The threads of the first locking bolt and the second locking bolt are opposite, and the bolt locking direction is opposite to the impeller rotation direction, so as to ensure that the bolts do not loosen when the impeller rotates at high speed. The function of the fixing groove is the same as that of the groove.

[0043] In the rotor structure of this invention, the permanent magnet 8 is centrally disposed inside the sheath 7 and forms an interference fit, so that the sheath 7 can protect the permanent magnet 8 under high-speed rotation. There are two end shafts 6, each positioned at one end of the permanent magnet 8 and in close contact with the end faces of the permanent magnet 8, to isolate the axial magnetic flux of the permanent magnet 8. These end shafts also connect the sheath 7 and the first ring 5 and the second ring 9, transmitting the torque of the permanent magnet 8 to the first ring 5 and the second ring 9. The first ring 5 and the second ring 9 are in close contact with the first end face of the end shaft 6 away from the rotor center, and their outer circumferential surfaces are in an interference fit with the sheath 7. The first short shaft 3 and the second short shaft 10 are respectively disposed inside the first ring 5 and the second ring 9 and form an interference fit, so that the torque on the permanent magnet 8 can be transmitted to the first short shaft 3 and the second short shaft 10 through the sheath 7.

[0044] The end shaft 6 has a sheath fitting section 601 and a ring fitting section 602. The sheath fitting section 601 is disposed inside the sheath 7 and is in close contact with the end face of the permanent magnet 8. The ring fitting section 602 is disposed inside the first ring 5 and the second ring 9 and can form a tight fit with the first ring 5 and the second ring 9 through interference fit or threaded connection.

[0045] In some embodiments, the first minor axis 3 and the second minor axis 10 are made of materials with a positive coefficient of thermal expansion.

[0046] In this technical solution, the first short shaft 3 and the second short shaft 10 are made of materials with a positive coefficient of expansion, while the ring sleeve is made of materials with a negative coefficient of expansion, which enables easy loading and unloading of the short shafts.

[0047] In the rotor structure of this invention, the sheath 7 is made of alloy material, such as high-temperature alloy or titanium alloy; the permanent magnet 8 is made of samarium cobalt; the first short shaft 3 and the second short shaft 10 can be made of ordinary stainless steel; the end shaft 6 is made of ordinary non-magnetic steel; and the first ring sleeve 5 and the second ring sleeve 9 are made of materials with negative expansion coefficients, such as negative expansion ceramic materials or negative expansion metal materials, specifically GdAgMg, MgB2, PbTiO3, AlFeO3, etc. Under high-temperature operating conditions, the sheath 7 and the permanent magnet 8 will undergo axial elongation, while the first ring sleeve 5 and the second ring sleeve 9 will undergo axial shortening. Through interference fit, the first ring sleeve 5 and the second ring sleeve 9 will limit the axial elongation of the sheath 7. By selecting a material with a negative expansion coefficient greater than that of the sheath 7, the sheath will have a tendency to shorten axially, offsetting the thermal elongation of the permanent magnet 8, thereby reducing or eliminating the influence of thermal deformation on the axial dimensions of the high-speed rotor assembly and ensuring the relative stability of the compressor blade tip clearance. The center of gravity of the high-speed rotating shaft can also be adjusted by designing different lengths of the first ring 5 and the second ring 9 and / or selecting materials with different densities.

[0048] The rotor structure of this invention solves two problems: firstly, the difficulty in locking the small impellers in existing high-speed centrifugal compressors with low flow rates and high pressure ratios; secondly, it addresses the issue that under the rated high-temperature environment of high-speed motor operation, the rotor undergoes significant axial elongation due to heat, leading to large variations in compressor tip clearance, large variations in compressor energy consumption, and a high risk of impeller-volute impact. It features a detachable short shaft with an interference fit and a ring sleeve made of a material with a negative expansion coefficient. On one hand, the positively expanding short shaft and the negatively expanding ring sleeve allow for easy assembly of the short shaft; on the other hand, the negatively expanding ring sleeve will axially contract under the rated high-temperature environment of the high-speed motor, offsetting the thermal elongation on other shaft sections and significantly reducing the axial thermal elongation of the high-speed rotor assembly, thereby ensuring the relative stability of the compressor tip clearance during operation. The detachable short shaft design of the high-speed rotor assembly facilitates the locking of the small-sized impellers on the rotor assembly.

[0049] The rotor structure of this invention employs an interference fit between a detachable short shaft and a ring sleeve made of a negative expansion coefficient material. The expansion coefficients of the two materials are positive and negative, facilitating the disassembly and assembly of the short shaft. The ring sleeve, made of a material with a negative expansion coefficient, utilizes its characteristic of axial contraction under the high-temperature environment of the high-speed motor's rated operation to offset the thermal expansion on other shaft sections, thereby reducing the axial thermal expansion of the high-speed shaft. Through the first ring sleeve and the second ring sleeve, which are coaxially placed on the left and right sides of the permanent magnet, the center of gravity of the high-speed shaft can be adjusted by adjusting the axial length of the first ring sleeve and the second ring sleeve.

[0050] The present invention also provides an electric motor, characterized in that it includes the rotor structure described above.

[0051] The present invention also provides a compressor, characterized in that it includes the above-described motor.

[0052] 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.

[0053] 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: A sheath (7) is provided with a permanent magnet (8), two end shafts (6), a first ring (5), and a second ring (9). The permanent magnet (8) is located between the two end shafts (6). One end shaft (6) is at least partially connected to the first ring (5), and the other end shaft (6) is at least partially connected to the second ring (9). The first ring (5) is provided with a first short shaft (3). One end shaft (6) is located between the first short shaft (3) and the permanent magnet (8). The second ring (9) is provided with a second short shaft (10). The other end shaft (6) is located between the second short shaft (10) and the permanent magnet (8). Along the axial direction of the permanent magnet (8), there is a first gap between the first short shaft (3) and one end shaft (6), and between the second short shaft (10) and the other end shaft (6). The first ring (5) and the second ring (9) are made of a material with a negative expansion coefficient.

2. The rotor structure according to claim 1, characterized in that: The first short shaft (3) includes a first mating section (301), a first sealing section (302), a first cold assembly section (303), and a first assembly section (304) connected in sequence. The outer diameters of the first mating section (301), the first cold assembly section (303), and the first assembly section (304) are all smaller than the outer diameter of the first sealing section (302). The first cold assembly section (303) and the first assembly section (304) are at least partially sleeved with the first ring sleeve (5). The first assembly section (304) has a first gap with one of the end shafts (6).

3. The rotor structure according to claim 2, characterized in that: The rotor structure also includes a thrust plate (4), which includes a third assembly section (401) and a thrust section (402). The thrust section (402) is located on the outer peripheral wall of the third assembly section (401). The third assembly section (401) is at least partially fitted in the sheath (7). The thrust section (402) is located outside the sheath (7) along the axial direction of the sheath (7). The portion of the third assembly section (401) in the sheath (7) abuts against the first ring sleeve (5). There is a second gap between the thrust section (402) and the sheath (7). The first cold assembly section (303) passes through the third assembly section (401) and extends into the first ring sleeve (5). The first sealing section (302) abuts against the end of the third assembly section (401).

4. The rotor structure according to claim 2, characterized in that: The first assembly section (304) has a groove at one end facing the end shaft (6), and the first mating section (301) has a connecting hole at one end away from the first sealing section (302). The first mating section (301) is connected to the first impeller (2) through the connecting hole and the first locking member (1).

5. The rotor structure according to claim 1, characterized in that: The second short shaft (10) includes a second mating section (1001), a second sealing section (1002), a second cold assembly section (1003), and a second assembly section (1004) connected in sequence. The outer diameters of the second mating section (1001), the second cold assembly section (1003), and the second assembly section (1004) are all smaller than the outer diameter of the second sealing section (1002). The second cold assembly section (1003) and the second assembly section (1004) are sleeved with the second ring sleeve (9). The second sealing section (1002) is located outside the sheath (7) and the second ring sleeve (9).

6. The rotor structure according to claim 5, characterized in that: The end of the sheath (7) away from the first short shaft (3) and the end of the second ring sleeve (9) away from the first short shaft (3) are located on the same plane. The end of the second sealing section (1002) facing the end shaft (6) abuts against the second ring sleeve (9). The second assembly section (1004) has a first gap with the other end shaft (6).

7. The rotor structure according to claim 5, characterized in that: The second assembly section (1004) has a fixing groove at one end facing the end shaft (6), and the second mating section (1001) has a mounting hole at one end away from the second sealing section (1002). The second mating section (1001) is connected to the second impeller (11) through the mounting hole and the second locking member (12).

8. The rotor structure according to claim 1, characterized in that: Both the first short axis (3) and the second short axis (10) are made of materials with a positive coefficient of thermal expansion.

9. An electric motor, characterized in that, The rotor structure includes any one of claims 1 to 8.

10. A compressor, characterized in that, Includes the motor as described in claim 9.

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