A design method for a rotor structure that reduces thermal elongation

Abstract

This invention provides a design method for a rotor structure that reduces thermal elongation. The method involves determining the length of the permanent magnet, selecting the material, and calculating its thermal elongation; setting the lengths and materials of the first and second heat-shrink sections and calculating their thermal elongation; setting the lengths and coefficients of thermal expansion of the first and second rings and calculating their high-temperature free thermal deformation; calculating the total elongation and total shrinkage; setting a proportionality coefficient between the two and deriving the proportional relationship between the coefficients of thermal expansion and the lengths of the first and second rings; and selecting a heat-shrinkable material based on the calculation results. This invention can quantitatively design the rotor structure according to different motor parameters, ensuring that the compressor blade tip clearance remains stable under high-speed and high-temperature operation. This invention belongs to the field of motor technology, enabling the motor to maintain a relatively stable compressor blade tip clearance during high-speed operation, improving the stability of motor operation, and thus saving energy consumption, achieving a good energy-saving effect.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a design method for a rotor structure that reduces thermal elongation. Background Technology

[0002] High-speed motors have extremely broad application prospects due to their technical characteristics such as small size, high power density, high transmission efficiency and high reliability, such as aerospace, national defense security, new energy industry, and home appliances.

[0003] 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 enables 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.

[0004] The high speed and high electromagnetic frequency of high-speed motors will increase the mechanical and electrical losses of the motor, thereby increasing the heat generated by the motor. Specifically, the high-frequency magnetic field will significantly increase the copper loss, iron loss and eddy current loss of high-speed motors. When the shaft rotates at high speed, it will cause intense friction with the air in the air gap, resulting in windage loss. As a result, the temperature and temperature rise of high-speed motors during rated operation are significantly higher than those of ordinary motors. This has become an important factor that the industry needs to consider in the design of high-speed motors.

[0005] Centrifugal compressors driven by high-speed motors have attracted much attention due to their high flow rate and high pressure ratio. However, for applications with high compressor energy efficiency requirements, smaller blade tip clearance is required. The high temperature generated by the high-speed motor during rated operation will cause the shaft material to deform significantly due to heat. Excessive axial elongation will lead to excessive changes in compressor energy efficiency and will also result in an insufficient blade tip clearance during rated operation, posing a risk of impact damage between the impeller and the volute.

[0006] The patent, with publication number CN121055649A and application date of August 27, 2025, entitled "A Rotor Structure, Motor, and Compressor," discloses a rotor structure. Specifically, it discloses the following: the rotor structure includes a sheath, within which a permanent magnet, two end shafts, a first ring, and a second ring are fitted. The permanent magnet is located between the two end shafts. One end shaft is at least partially fitted with the first ring, and the other end shaft is at least partially fitted with the second ring. A first short shaft is fitted inside the first ring, and one end shaft is located between the first short shaft and the permanent magnet. A second short shaft is fitted inside 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, there is a first gap between the first short shaft and one end shaft, and between the second short shaft and the other end shaft. The first and second rings are made of a material with a negative coefficient of thermal expansion.

[0007] In the aforementioned public documents, by setting the first and second ring sleeves to materials with a negative coefficient of thermal expansion, axial contraction can occur when the motor runs under high-temperature ring conditions, thereby offsetting the thermal expansion on other shaft sections and significantly reducing the axial thermal expansion of the high-speed rotor assembly, thus keeping the compressor blade tip clearance relatively stable during operation.

[0008] However, it is impossible to quantitatively design the relevant parameters of the rotor structure based on the actual parameters of different motors, making it difficult to ensure that the compressor blade tip clearance remains relatively stable when the motor is running at high speed. Summary of the Invention

[0009] This invention provides a design method for a rotor structure that reduces thermal elongation, aiming to solve the problem that existing technologies only qualitatively use negative expansion materials, but cannot quantitatively design the relevant parameters of the rotor structure according to the actual parameters of different motors, making it difficult to ensure that the compressor blade tip clearance remains relatively stable under high-speed motor operation.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a design method for a rotor structure that reduces thermal elongation. The rotor structure includes a sheath, and the sheath contains a thermally elongated section and a thermally contracted section; the thermally elongated section includes a permanent magnet. Its characteristic is that it includes the following steps: Determine the diameter and length of the permanent magnet. ; Select the material of the permanent magnet and the material of the sheath; Set the length of each part of the heated elongation section except for the permanent magnet, and select the material for the corresponding part; The lengths of each part of the heat-shrinkable section are defined, and the coefficient of thermal expansion of the heat-shrinkable section is given. ; Calculate the total elongation of the heated section at temperature T2. ; Calculate the total shrinkage of the heat-shrinking section at temperature T2. ; set up and The proportionality coefficient between them is used to calculate the coefficient of thermal expansion. The proportional relationship between the lengths of the various parts of the heat-shrinkable section; According to the calculated coefficient of thermal expansion Based on the proportional relationship between the length of each part of the heat-shrinkable section and the length of the heat-shrinkable section, a suitable heat-shrinkable material is selected.

[0011] In one embodiment, the heated elongation section further includes a first heat-shrinking section and a second heat-shrinking section; and the first heat-shrinking section and the second heat-shrinking section are disposed at both ends of the permanent magnet.

[0012] In one embodiment, the length of the first heat-shrink section is included in the length of each portion of the heated elongation section excluding the permanent magnet. Length of the second heat-shrink section Select the materials for the first heat-shrinking section and the second heat-shrinking section, and calculate the thermal elongation of the first heat-shrinking section. Calculate the thermal elongation of the second heat-shrink section. .

[0013] In one embodiment, the heat-shrinkable section includes a first ring and a second ring. The end of the first heat-shrinkable section away from the permanent magnet is connected to a first assembly section, and the first ring is sleeved around the periphery of the first assembly section. The end of the second heat-shrinkable section away from the permanent magnet is connected to a second assembly section, and the second ring is sleeved around the periphery of the second assembly section.

[0014] In one embodiment, the length of the first ring is set as part of the setting of the lengths of each portion of the heat-shrinkable section. The length of the second ring The coefficients of thermal expansion of the first ring and the second ring are: Calculate the free thermal deformation of the first ring at temperature T2. Calculate the free thermal deformation of the second ring at temperature T2. .

[0015] In one embodiment, the total shrinkage amount = (0.8-1.0) Total elongation ; .

[0016] In one embodiment, the total length of the first loop and the second loop is set, and simultaneously according to Sure and The length.

[0017] In one embodiment, the step is based on the coefficient of thermal expansion of the heated contraction section. Select heat-shrinkable materials; such as those with a coefficient of thermal expansion. If a heat-shrinkable material cannot be selected within the range, the lengths of all parts of the heat-elongated section except the permanent magnet need to be reset, the lengths of all parts of the heat-shrinkable section need to be reset, and the subsequent steps need to be repeated in sequence.

[0018] In one embodiment, a first impeller is provided at the end of the first assembly section away from the permanent magnet, and a second impeller is provided at the end of the second assembly section away from the permanent magnet; The first impeller has a first elastic component on the side opposite to the first assembly section, and the second impeller has a second elastic component on the side opposite to the second assembly section.

[0019] In one embodiment, based on the elastic modulus of the selected first ring and second ring materials... Select the elastic coefficients of the first elastic component and the second elastic component. ,make sure This ensures that after the rotor stops working and the temperature returns to room temperature, the first and second ring sleeves can return to their original lengths.

[0020] The beneficial effects of this invention compared to existing technologies are as follows: Through the above steps, this invention can quantitatively select and design the materials and lengths of the heat-extension and heat-contraction sections according to different parameters of the motor. This allows for full utilization of the axial contraction characteristic of the heat-contraction section at high temperatures, which offsets the thermal expansion on other shaft sections, thereby reducing the overall axial thermal expansion. This ensures that the compressor blade tip clearance remains relatively stable during high-speed motor operation, overcoming the deficiency of existing technologies that only qualitatively employ negative expansion materials but cannot quantitatively match them. This invention belongs to the field of motor technology, enabling the motor to maintain a relatively stable compressor blade tip clearance during high-speed operation, improving the stability of motor operation, and thus saving energy consumption, achieving a good energy-saving effect.

[0021] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other objects, features and advantages of the present invention more obvious and understandable, preferred embodiments are described in detail below. Attached Figure Description

[0022] Figure 1 A simplified schematic diagram illustrating the steps of a design method for reducing thermal elongation of a rotor structure provided by an embodiment of the present invention; Figure 2 A cross-sectional view of the rotor structure designed according to a method for designing a rotor structure to reduce thermal elongation provided in an embodiment of the present invention; Figure 3 Detailed annotation of the cross-sectional view of the rotor structure designed according to the design method for reducing thermal elongation provided in this embodiment of the invention; Figure 4 for Figure 3 A magnified view of region A in the image; Figure 5 for Figure 3 A magnified view of region B in the image; Figure 6 A schematic diagram of the first short shaft structure of a design method for reducing thermal elongation of a rotor structure provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the first ring of a design method for reducing thermal elongation of a rotor structure provided in an embodiment of the present invention; Figure 8 A schematic diagram of the first impeller of a design method for reducing thermal elongation of a rotor structure provided in an embodiment of the present invention; Figure label: 10. Sheath; 20. Permanent magnet; 30. First short shaft; 301. First heat-shrink section; 302. First assembly section; 31. Second short shaft; 311. Second heat-shrink section; 312. Second assembly section; 40. First ring, 41. Second ring. 50. First impeller; 51. Second impeller; 60. First elastic component; 61. Second elastic component; 70. First fastener; 71. Second fastener; 80. Thrust plate; 90. Sealing ring. Detailed Implementation

[0023] 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, not all, of the embodiments of the present invention. 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.

[0024] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0027] Please see Figure 1-8 A design method for a rotor structure to reduce thermal elongation, the rotor structure including a sheath 10, wherein a thermally elongated section and a thermally contracted section are provided inside the sheath; the thermally elongated section includes a permanent magnet 20; Includes the following steps: S01: Determine the diameter and length of the permanent magnet 20. ; S02: Select the materials of the permanent magnet 20 and the sheath 10; S03: Set the length of each part of the heated elongation section except for the permanent magnet 20, and select the material for the corresponding part; S04: Set the length of each part of the heat-shrinkable section, and the coefficient of thermal expansion of the heat-shrinkable section is... ; S05: Calculate the total elongation of the heated elongated section at temperature T2. ; Calculate the total shrinkage of the heat-shrinking section at temperature T2. ; S06: Settings and The proportionality coefficient between them is used to calculate the coefficient of thermal expansion. The proportional relationship between the lengths of the various parts of the heat-shrinkable section; S07: Based on the calculated coefficient of thermal expansion Based on the proportional relationship between the length of each part of the heat-shrinkable section and the length of the heat-shrinkable section, the heat-shrinkable material is selected.

[0028] The temperature generated when the motor is running at high speed is T2.

[0029] In this embodiment, the above steps allow for the selection and design of the materials and lengths of the heat-expanding and heat-shrinking sections based on different motor parameters. This enables full utilization of the axial contraction characteristic of the heat-shrinking section at high temperatures, offsetting the thermal expansion on other shaft sections and reducing the overall axial thermal expansion. This ensures that the compressor blade tip clearance remains relatively stable even during high-speed motor operation.

[0030] In this embodiment, the heated elongation section further includes a first heat-shrinking section 301 and a second heat-shrinking section 311; and the first heat-shrinking section 301 and the second heat-shrinking section 311 are disposed at both ends of the permanent magnet 20.

[0031] In S03: The length of the first heat-shrink section 301 is defined as one of the lengths of the portion of the heated elongation section excluding the permanent magnet. The length of the second heat-shrink section 311 Select the materials of the first heat-shrink section 301 and the second heat-shrink section 311, and calculate the thermal elongation of the first heat-shrink section 301. The thermal elongation of the second heat-shrink section 311 is calculated as follows: .

[0032] Select the materials for the first heat-shrink section 301 and the second heat-shrink section 311, and determine the coefficients of thermal expansion of the materials for the first heat-shrink section 301 and the second heat-shrink section 311. With elastic modulus .

[0033] , These are the thermal elongations under the condition that the interference fit between the permanent magnet 20 and the first heat-shrink section 301 and the second heat-shrink section 311 is secure and there is no axial relative slippage: The temperature of the motor at room temperature is T1, and the temperature generated when the motor is running at high speed is T2. ; The coefficient of thermal expansion of the sheath material 10; The elastic modulus of the sheath material 10; The cross-sectional area of ​​the sheath 10; The coefficient of thermal expansion of the selected materials for the first heat-shrink section 301 and the second heat-shrink section 311; The elastic modulus of the selected first heat-shrinking section 301 and second heat-shrinking section 311 materials; The cross-sectional areas of the first heat-shrink section 301 and the second heat-shrink section 311 are given.

[0034] In this embodiment, the heat-shrinkable section includes a first ring 40 and a second ring 41. The end of the first heat-shrinkable section 301 away from the permanent magnet 20 is connected to a first assembly section 302, and the first ring 40 is sleeved around the periphery of the first assembly section 302. The end of the second heat-shrinkable section 311 away from the permanent magnet 20 is connected to a second assembly section 312, and the second ring 41 is sleeved around the periphery of the second heat-shrinkable section 311. In S04, the length of the first ring 40 is set in the process of setting the length of each part of the heat-shrinkable section. The length of the second ring 41 The coefficients of thermal expansion of the first ring 40 and the second ring 41 are: Calculate the free thermal deformation of the first ring 40 at temperature T2. Calculate the free thermal deformation of the second ring 41 at temperature T2. .

[0035] In S05: the cross-sectional area of ​​permanent magnet 20 is .

[0036] Determine the coefficient of thermal expansion of permanent magnet 20 With elastic modulus .

[0037] The thermal elongation is the amount of thermal expansion under the condition that the interference fit between the permanent magnet 20 and the sheath 10 is secure and there is no axial relative slippage. The temperature of the motor at room temperature is T1, and the temperature generated when the motor is running at high speed is T2. .

[0038] In S06: Total shrinkage = (0.8-1.0) Total elongation ; .

[0039] In a further embodiment, it also includes S07: based on the thermal expansion coefficient of the heated contraction section... Select heat-shrinkable materials; such as those with a coefficient of thermal expansion. If a heat-shrinkable material cannot be selected within the range, the lengths of all parts of the heat-elongated section except the permanent magnet need to be reset, the lengths of all parts of the heat-shrinkable section need to be reset, and the subsequent steps need to be repeated in sequence.

[0040] Specifically, the coefficient of thermal expansion If a heat-shrinkable material cannot be selected within the specified range, the length of the first heat-shrink section 301 needs to be reset. The length of the second heat-shrink section 311 ;Reset the length of the first ring 40 The length of the second ring 41 This means returning to steps S03 and S04 to recalculate the relevant parameters.

[0041] It also includes S08: setting the total length of the first ring 40 and the second ring 41, and simultaneously according to determining and length.

[0042] In a further embodiment, as shown in Figure 3 and Figure 4 , a first impeller (50) is provided at an end of said first fitting section (302) away from said permanent magnet (20), and a second impeller (51) is provided at an end of said second fitting section (312) away from said permanent magnet (20); a side of said first impeller (50) facing away from said first fitting section (302) is provided with a first elastic member (60), and a side of said second impeller (51) facing away from said second fitting section (312) is provided with a second elastic member (61).

[0043] In this embodiment, by providing the first elastic member (60) and the second elastic member (61) on the first fitting section (302) and the second fitting section (312) respectively, the first impeller (50) and the second impeller (51) can be pushed under the action of the first elastic member (60) or the second elastic member (61) respectively to move towards a direction close to the first ring sleeve (40) or the second ring sleeve (41).

[0044] Therefore, when the temperature of the motor rises, since the lengths of the first ring sleeve (40) and the second ring sleeve (41) contract, the first elastic member (60) and the second elastic member (61) can push the first impeller (50) and the second impeller (51) to move towards the direction close to the first ring sleeve (40) and the second ring sleeve (41), so that the gaps between the first impeller (50), the second impeller (51) and the volute matched therewith can be increased, thereby ensuring that no impact occurs between the first impeller (50), the second impeller (51) and the volute.

[0045] In a further embodiment, the method further comprises step S09: selecting an elastic coefficient k of said first elastic member (60) and said second elastic member (61) according to the elastic modulus E of the material of the selected first ring sleeve (40) and said second ring sleeve (41), ensuring k < E, so that after the rotor stops working and the temperature returns to room temperature, said first ring sleeve (40) and said second ring sleeve (41) can return to their original lengths.

[0046] The first heat-shrink fitting section (301) and the first fitting section (302) are of an integrally formed structure, forming an integral first short shaft (30) structure. The diameter of said first fitting section (302) is smaller than the diameter of said first heat-shrink fitting section (301), and the end of the first fitting section (302) extends to the periphery of the sheath (10).

[0047] The second heat-shrink fitting section (311) and the second fitting section (312) are of an integrally formed structure, forming an integral second short shaft (30) structure. The diameter of said second fitting section (312) is smaller than the diameter of said second heat-shrink fitting section (311), and the end of the second fitting section (312) extends to the periphery of the sheath (10).

[0048] In this embodiment, the first ring 40, the first impeller 50, the first elastic component 60 and other structures are all disposed on the first assembly section 302, and the first impeller 50 can slide along the first assembly section 302.

[0049] In this embodiment, the second ring 41, the second impeller 51, the second elastic component 61 and other structures are all disposed on the second assembly section 312, and the first impeller 50 can slide along the second assembly section 312.

[0050] In a further embodiment, a first fastener 70 is provided at a position on the first elastic member 60 away from the first impeller 50; A second fastener 71 is provided at a position opposite to the second impeller 51 on the second elastic member 61.

[0051] In this embodiment, by setting the first fastener 70, the first elastic member 60 can be limited, thereby supporting the first impeller 50. At the same time, the first fastener 70, together with the first elastic member 60, enables the first elastic member 60 to stably abut against the circumference of the first impeller 50, making the force on the first impeller 50 more uniform.

[0052] Similarly, by setting the second fastener 71, the second elastic component 61 can be limited, thereby supporting the second impeller 51. At the same time, the second fastener 71, together with the second elastic component 61, allows the second elastic component 61 to stably abut against the circumference of the second impeller 51, making the force on the second impeller 51 more even.

[0053] In this embodiment, both the first elastic component 60 and the second elastic component 61 are spring washers. These spring washers have high damping and can provide a large thrust to drive the first impeller 50 and the second impeller 61 to move along the axial direction.

[0054] In this embodiment, both the second fastener 71 and the first fastener 70 adopt a nut structure. Therefore, at the ends of the first assembly section 302 and the second assembly section 312, threaded structures that cooperate with the nuts are provided.

[0055] Therefore, by rotating the nut, the nut can be moved axially along the first assembly section 302, thereby adjusting the degree of compression of the first elastic member 60, and thus adjusting the elastic force of the first elastic member 60 pressing against the first impeller 50.

[0056] By rotating the nut, the nut can be moved axially along the second assembly section 312, thereby adjusting the degree of compression of the second elastic member 61 and thus adjusting the elastic force of the second elastic member 61 pressing against the second impeller 51.

[0057] Furthermore, the first elastic member 60 can prevent the first fastener 70 from loosening. The second elastic member 61 can also prevent the second fastener 71 from loosening.

[0058] In a further embodiment, a thrust plate 80 is fitted onto the first assembly section 302; the thrust plate 80 is disposed between the first ring 40 and the first impeller 50.

[0059] One end face of the thrust disc 80 corresponds to the first impeller 50, and the other end face abuts against the end of the first ring sleeve 40, thus limiting the end of the first ring sleeve 40. The first fastener 70 also limits and abuts against the thrust disc 80, thus axially limiting the thrust disc 80.

[0060] It should be noted that in this embodiment, the thrust plate 80 is only provided near the first impeller 50, while the thrust plate 80 structure is not provided near the second impeller 51.

[0061] The two end faces of the second impeller 51 abut against the second assembly section 312 and the second elastic component 61 respectively, thereby achieving axial positioning of the second impeller 51.

[0062] This results in only a single thrust plate in this application, making the overall structural layout simpler.

[0063] In a further embodiment, a sealing ring 90 is also fitted on the first assembly section 302; the sealing ring 90 abuts between the thrust plate 80 and the first impeller 50.

[0064] In this embodiment, the sealing ring 90 can move axially along the first assembly section 302, and the sealing ring 90 is fixed on the first assembly section 302 under the action of the first fastener 70.

[0065] At the same time, the sealing ring 90 can seal the first impeller 50 to prevent air leakage when the first impeller 50 is working.

[0066] The working principle of this application is as follows: The rotor structure includes a permanent magnet 20, a first heat-shrink section 301 and a second heat-shrink section 311 at both ends, and a first ring sleeve 40 and a second ring sleeve 41 respectively sleeved around the first assembly section 302 and the second assembly section 312. The first ring sleeve 40 and the second ring sleeve 41 are made of materials with a negative coefficient of thermal expansion. Common materials include negative expansion ceramic materials, GdAgMg, MgB2, PbTiO3, and AlFeO3, which undergo axial contraction at high temperatures.

[0067] By determining the geometric lengths and material parameters (coefficients of thermal expansion) of the permanent magnet 20, the first heat-shrinking section 301, the second heat-shrinking section 311, the first ring 40, and the second ring 41. Elastic modulus ).

[0068] Calculate the total thermal elongation of the permanent magnet 20, the first heat-shrink section 301, and the second heat-shrink section 311 at high temperature. And the heat shrinkage of the first ring 40 and the second ring 41 .

[0069] The total shrinkage is set to be approximately 0.8 to 1.0 times the total elongation, thereby deriving the proportional relationship between the required coefficient of thermal expansion and the length of the first ring 40 and the second ring 41.

[0070] Select a suitable heat-shrinkable material based on the calculation results. If this is not feasible, iteratively adjust the length parameter until it meets the requirements.

[0071] A first elastic component 60, a second elastic component 61, a first fastener 70, and a second fastener 71 are provided on the outer sides of the first impeller 50 and the second impeller 51. When the motor heats up, the first ring 40 and the second ring 41 contract, pushing the first impeller 50 and the second impeller 51 inward through the first elastic component 60 and the second elastic component 61, thereby increasing the gap between the first impeller 50, the second impeller 51, and the volute.

[0072] After the motor cools down, the elastic coefficients of the first elastic component 60 and the second elastic component 61... The elastic modulus of the material is less than that of the first ring 40 and the second ring 41. This can help restore the first loop 40 and the second loop 41 to their original length.

[0073] This application overcomes the shortcomings of existing technologies that only qualitatively employ negative expansion materials but cannot quantitatively match them. It allows for precise calculation and design of rotor components based on the actual parameters of different motors, ensuring reliable compensation effects.

[0074] The thermal contraction of the first ring sleeve 40 and the second ring sleeve 41, along with the thermal expansion of the first hot-swapped section 301, the second hot-swapped section 311, and the permanent magnet 20, mutually offset each other, significantly reducing the overall axial thermal expansion of the rotor. This maintains a relatively stable compressor tip clearance under high-speed, high-temperature operating conditions, preventing impeller and volute impact damage caused by thermal expansion. It effectively prevents drastic fluctuations in compressor performance caused by excessively large or small tip clearances, contributing to maintaining efficient operation. The first elastic component 60, the second elastic component 61, the first fastener 70, and the second fastener 71 are provided so that they can not only push the first impeller 50 and the second impeller 51 to form compensation at high temperatures, but also allow the first ring sleeve 40 and the second ring sleeve 41 to return to their original length after the temperature recovers, thereby improving the service life of the shaft and ensuring the stability and reliability of repeated use.

[0075] If a suitable heat-shrinkable material cannot be selected within the current parameter range, the method allows the lengths of the first heat-shrinking section 301, the second heat-shrinking section 311, the first ring 40, and the second ring 41 to be reset and recalculated, which improves the design success rate and flexibility.

[0076] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A design method for a rotor structure to reduce thermal elongation, the rotor structure including a sheath, and a thermally elongated section and a thermally contracted section disposed within the sheath; the thermally elongated section includes a permanent magnet; Its features are, Includes the following steps: Determine the diameter and length of the permanent magnet. ; Select the material of the permanent magnet and the material of the sheath; Set the length of each part of the heated elongation section except for the permanent magnet, and select the material for the corresponding part; The lengths of each part of the heat-shrinkable section are defined, and the coefficient of thermal expansion of the heat-shrinkable section is given. ; Calculate the total elongation of the heated section at temperature T2. ; Calculate the total shrinkage of the heat-shrinkable section at temperature T2. ; set up and The proportionality coefficient between them is used to calculate the coefficient of thermal expansion. The proportional relationship between the lengths of the various parts of the heat-shrinkable section; According to the calculated coefficient of thermal expansion Based on the proportional relationship between the length of each part of the heat-shrinkable section and the length of the heat-shrinkable section, a suitable heat-shrinkable material is selected.

2. The design method for reducing thermal elongation of the rotor structure according to claim 1, characterized in that, The heated elongation section further includes a first heat-shrinking section and a second heat-shrinking section; and the first heat-shrinking section and the second heat-shrinking section are disposed at both ends of the permanent magnet.

3. The design method for reducing thermal elongation of the rotor structure according to claim 2, characterized in that, Among the lengths of the heated elongation section excluding the permanent magnet, the length of the first heat-shrink section is... Length of the second heat-shrink section Select the materials for the first heat-shrinking section and the second heat-shrinking section, and calculate the thermal elongation of the first heat-shrinking section. Calculate the thermal elongation of the second heat-shrink section. .

4. The design method for reducing thermal elongation of the rotor structure according to claim 3, characterized in that, The heat-shrinkable section includes a first ring and a second ring. The end of the first heat-shrinkable section away from the permanent magnet is connected to a first assembly section, and the first ring is sleeved around the first assembly section. The end of the second heat-shrinkable section away from the permanent magnet is connected to a second assembly section, and the second ring is sleeved around the second assembly section.

5. The design method for reducing thermal elongation of the rotor structure according to claim 4, characterized in that, In setting the length of each part of the heat-shrinkable section, the length of the first ring is set. The length of the second ring The coefficients of thermal expansion of the first ring and the second ring are: Calculate the free thermal deformation of the first ring at temperature T2. Calculate the free thermal deformation of the second ring at temperature T2. .

6. The design method for a rotor structure with reduced thermal elongation according to claim 5, characterized in that, The total shrinkage = (0.8-1.0) Total elongation ; .

7. The design method for a rotor structure with reduced thermal elongation according to claim 6, characterized in that, Set the total length of the first loop and the second loop, and simultaneously according to Sure and The length.

8. The design method for reducing thermal elongation of the rotor structure according to claim 1, characterized in that, The thermal expansion coefficient of the heated shrinkage section Select heat-shrinkable materials; such as those with a coefficient of thermal expansion. If a heat-shrinkable material cannot be selected within the range, the lengths of all parts of the heat-elongated section except the permanent magnet need to be reset, the lengths of all parts of the heat-shrinkable section need to be reset, and the subsequent steps need to be repeated in sequence.

9. The design method for a rotor structure to reduce thermal elongation according to claim 4, characterized in that, The first assembly section is provided with a first impeller at the end away from the permanent magnet, and the second assembly section is provided with a second impeller at the end away from the permanent magnet; The first impeller has a first elastic component on the side opposite to the first assembly section, and the second impeller has a second elastic component on the side opposite to the second assembly section.

10. The design method for a rotor structure with reduced thermal elongation according to claim 9, characterized in that, Based on the elastic modulus of the selected first and second ring materials Select the elastic coefficients of the first elastic component and the second elastic component. ,make sure This ensures that after the rotor stops working and the temperature returns to room temperature, the first and second ring sleeves can return to their original lengths.

Images