A remanufactured motor with a crescent-shaped structure having unequal air gaps and a manufacturing method thereof

Abstract

The present invention provides a remanufactured motor with an unequal air gap crescent-shaped structure and a manufacturing method. By removing part of the rotor cage, the cage cross-sectional area is reduced and the cage winding resistance is increased, so that the modified induction motor can generate a higher starting torque than the original induction motor. By installing permanent magnets in the rotor space released by removing part of the rotor cage, the motor can generate sufficient air gap magnetic field energy during operation. By removing part of the outer circumference of the rotor, the rotor is made into an unequal air gap structure, reducing the motor back electromotive force harmonic content and cogging torque to meet the motor operation needs. Compared with the new permanent magnet synchronous motor, this design is based on the upgraded remanufacturing of the old motor, and the price is relatively lower than that of the new motor. Compared with the existing motor remanufacturing, the present invention does not require a matching inverter to start, and the permanent magnet will not fall off, and the structure is more stable.

Description

Technical Field

[0001] The present invention relates to the technical field of phase asynchronous motor reconstruction, and in particular to a remanufactured motor with an unequal air gap crescent-shaped structure and a manufacturing method thereof. Background Art

[0002] According to statistics, in 2015, electric motors accounted for approximately 65% ​​of my country's total electricity consumption. Despite this significant energy consumption, the overall energy efficiency of electric motors in China remains low. Currently, the Chinese motor market retains a large number of inefficient induction motors, such as the Y and YB series. Directly replacing these motors with high-efficiency motors would, on the one hand, be expensive, making it difficult for companies to recoup the costs quickly. On the other hand, the disposal of discarded motors would cause significant environmental pollution. Existing technologies typically improve the energy efficiency of inefficient motors through remanufacturing, which involves internal improvements to the motors to enhance their energy efficiency. The most common approach is to replace the silicon steel laminations on the rotor with amorphous materials, which can achieve a certain degree of energy efficiency improvement. Another approach involves attaching permanent magnets to the rotor surface or remanufacturing the motor by replacing the original rotor.

[0003] However, the preparation cost of amorphous materials is high, the processing conditions are harsh, and they are easily denatured when used at high temperatures. Therefore, replacing the silicon steel sheets on the rotor with amorphous materials cannot be widely used. In the method of attaching permanent magnets to the rotor surface, the permanent magnets are easy to fall off and need to be equipped with a frequency converter, so it is not suitable for widespread application. Remanufacturing the motor by replacing the rotor not only wastes resources, but also has high processing costs for the new rotor, so it is not suitable for widespread application. Summary of the Invention

[0004] In view of this, an embodiment of the present invention provides a remanufactured motor and a manufacturing method with an unequal air gap crescent-shaped structure to solve the problems of high preparation cost and difficulty in amorphous processing of amorphous materials when replacing silicon steel sheets on the rotor with amorphous materials in the prior art; the problem of easy falling off of permanent magnets when attaching permanent magnets to the rotor surface in the prior art; and the problem of not considering optimizing the air gap magnetic field during the transformation, resulting in the inability to optimize the harmonic amount of the generated potential.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] A first aspect of the present invention discloses a method for manufacturing a remanufactured motor having a crescent-shaped structure with unequal air gaps, comprising: removing a portion of a rotor cage to release a certain amount of rotor space;

[0007] Installing a permanent magnet in the rotor space;

[0008] Part of the outer circumference of the rotor is removed to make the rotor into an unequal air gap structure.

[0009] Preferably, removing part of the rotor cage to release a certain amount of rotor space includes:

[0010] A crescent groove is cut through the rotor axis as the center line, and the opening of the crescent groove faces the rotor axis.

[0011] Preferably, there are multiple through-crescent grooves, and the multiple through-crescent grooves are evenly distributed along the circumference of the rotor.

[0012] Preferably, the central angle of the circle penetrating the crescent groove is 87°, the inner arc radius of the circle penetrating the crescent groove is 61 mm, and the outer arc radius is 67 mm.

[0013] Preferably, the step of installing a permanent magnet in the rotor space includes:

[0014] Permanent magnets and insulating materials are placed in the rotor space, and the insulating materials are spaced between the rotor space and the permanent magnets, so that the permanent magnets form a skewed pole state.

[0015] Preferably, the removing of part of the outer circumference of the rotor to make the rotor into an unequal air gap structure comprises:

[0016] Part of the outer circumference of the rotor is removed to form an eccentric circle on the outer circumference of the rotor, and the eccentric circle is aligned with the through crescent groove.

[0017] Preferably, the center of the eccentric circle is offset 9.82 mm radially outward from the center of the rotor, and the radius of the eccentric circle is 74.48 mm.

[0018] Preferably, after removing part of the outer circumference of the rotor to make the rotor into an unequal air gap structure, the method further comprises:

[0019] The outer periphery of the rotor is covered with a magnetic isolation sleeve.

[0020] Preferably, after the outer periphery of the rotor is covered with a magnetic isolation sleeve, the method further comprises:

[0021] The remanufactured rotor is installed with other parts of the motor.

[0022] The second aspect of the present invention discloses a remanufactured motor with a crescent-shaped structure having unequal air gaps, which is a remanufactured motor with a crescent-shaped structure having unequal air gaps manufactured according to the manufacturing method disclosed in the first aspect of the present invention.

[0023] From the above content, it can be seen that the present invention discloses a remanufactured motor with an unequal air gap crescent-shaped structure and a manufacturing method. First, a certain amount of rotor space is released by removing part of the rotor cage; then, permanent magnets are installed in the rotor space, and finally, part of the outer peripheral surface of the rotor is removed to make the rotor into an unequal air gap structure. Compared with the new permanent magnet synchronous motor, this design is based on the upgraded remanufacturing of the old motor, so the price of the motor is much lower than that of the new motor, and at the same time, the added value of the old motor can be well utilized. Compared with the existing motor remanufacturing method, the patent of the present invention does not require a matching inverter for starting, and there will be no permanent magnet falling off. At the same time, while ensuring the stability of the structure, the original motor components can be retained to the greatest extent to achieve high-value recycling of waste motors. At the same time, through the manufacturing method disclosed above, a portion of the rotor cage is removed, reducing the cage cross-sectional area and increasing the cage winding resistance. This allows the modified induction motor to generate higher starting torque than the original induction motor. Permanent magnets are installed in the rotor space freed by the removal of the rotor cage, enabling the motor to generate sufficient air gap magnetic field energy during operation. Furthermore, by removing a portion of the rotor's outer circumference, the rotor is created into an unequal air gap structure, reducing the motor's back EMF harmonic content and cogging torque to meet the motor's operating requirements. The topological design of the motor rotor in this scheme reconstructs the design theory of the "cage" of the induction motor. During permanent magnetization remanufacturing, the starting and operating functions of the original induction motor's cage are "decoupled" from each other within the originally unified cage, retaining only the starting function. Therefore, a portion of the cage can be removed, resolving the conflict between the starting cage and the permanent magnet poles in the rotor space arrangement of the "self-starting permanent magnet motor." BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0025] Figure 1 A flow chart of a method for manufacturing a remanufactured motor having a crescent-shaped structure with unequal air gaps provided by an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of a rotor structure with unequal air gaps after removing part of the squirrel cage according to an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of a rotor structure equipped with permanent magnets according to an embodiment of the present invention;

[0028] Figure 4A diagram showing the spatial distribution of magnetic steel in a crescent groove provided by an embodiment of the present invention;

[0029] Figure 5 A schematic diagram of the rotor structure after adding a magnetic isolation sleeve according to an embodiment of the present invention;

[0030] Figure 6 A diagram showing the distribution of magnetic lines of force of a motor in the motor performance analysis provided by an embodiment of the present invention;

[0031] Figure 7 A graph showing an induced potential curve in the motor performance analysis provided by an embodiment of the present invention;

[0032] Figure 8 A torque curve diagram for motor performance analysis provided by an embodiment of the present invention;

[0033] Figure 9 This is a graph showing the speed changing over time in the motor performance analysis provided by an embodiment of the present invention.

[0034] Among them, the rotor-10, the crescent groove-20, the magnetic steel-30, and the magnetic isolation sleeve-40. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] In this application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0037] The embodiment of the present invention provides a method for manufacturing a remanufactured motor having a crescent-shaped structure with unequal air gaps, see Figures 1 to 3 , is a flow chart of a method for manufacturing a remanufactured motor having a crescent-shaped structure with unequal air gaps according to the present invention, wherein the method for manufacturing a remanufactured motor having a crescent-shaped structure with unequal air gaps comprises at least the following steps:

[0038] S1. Remove part of the rotor cage to free up some rotor space.

[0039] S2. Installing a permanent magnet in the rotor space;

[0040] S3. Removing part of the outer circumference of the rotor to make the rotor into an unequal air gap structure.

[0041] It should be noted that, in step S1, reference Figure 2 On the induction motor rotor 10, by considering the cross-sectional area of ​​the rotor 10 and removing part of the original squirrel cage along the axial direction of the rotor 10, a certain amount of rotor 10 space is released. When the squirrel cage cross-sectional area is reduced, the squirrel cage winding resistance is correspondingly increased, so that the modified induction motor can generate higher starting torque than the original induction motor.

[0042] In step S2, referring to Figure 3 By installing the permanent magnet 30 in the space of the rotor 10, the motor can generate sufficient air gap magnetic field energy during operation, thereby meeting the motor operation needs.

[0043] In step S3 , by removing part of the outer circumference of the rotor 10 , the rotor 10 is made into an unequal air gap structure, thereby reducing the back electromotive force harmonic content and the cogging torque of the motor.

[0044] It should also be noted that when executing step S3, it can be executed before executing step S1, or it can be executed after executing step S1 and before step S2. The above execution steps are only for illustration. Therefore, executing step S3 does not necessarily have to be executed after executing step S2.

[0045] An embodiment of the present invention provides a method for manufacturing a remanufactured motor having an unequal air gap crescent-shaped structure. First, a certain amount of rotor space is released by removing part of the rotor cage; then, permanent magnets are installed in the rotor space; finally, part of the outer peripheral surface of the rotor is removed to make the rotor into an unequal air gap structure. Compared with new permanent magnet synchronous motors, this design is based on the upgraded remanufacturing of old motors. Therefore, the price of the motor is much lower than that of new motors, and the added value of old motors can be well utilized. Compared with existing motor remanufacturing methods, the patent of the present invention does not require a matching inverter for starting, and permanent magnets will not fall off. At the same time, while ensuring structural stability, the original motor components can be retained to the greatest extent, so as to achieve high-value recycling of waste motors. At the same time, through the manufacturing method disclosed above, a portion of the rotor cage is removed, reducing the cage cross-sectional area and increasing the cage winding resistance. This allows the modified induction motor to generate higher starting torque than the original induction motor. Permanent magnets are installed in the rotor space freed by the removal of the rotor cage, enabling the motor to generate sufficient air gap magnetic field energy during operation. Furthermore, by removing a portion of the rotor's outer circumference, the rotor is created into an unequal air gap structure, reducing the motor's back EMF harmonic content and cogging torque to meet the motor's operating requirements. The topological design of the motor rotor in this scheme reconstructs the design theory of the "cage" of the induction motor. During permanent magnetization remanufacturing, the starting and operating functions of the original induction motor's cage are "decoupled" from each other within the originally unified cage, retaining only the starting function. Therefore, a portion of the cage can be removed, resolving the conflict between the starting cage and the permanent magnet poles in the rotor space arrangement of the "self-starting permanent magnet motor."

[0046] Furthermore, based on the above disclosed method for manufacturing a remanufactured motor with an unequal air gap crescent-shaped structure, during the execution of step S1, the specific execution process of step S1 is as follows:

[0047] A crescent groove is cut through the rotor axis as the center line, and the opening of the crescent groove faces the rotor axis.

[0048] It should be noted that the through crescent groove 20 is a space in the rotor 10. The through crescent groove 20 is cut through the silicon steel sheets of the rotor 10 with the axis as the centerline. To maximize the permanent magnet area (axial direction), a "crescent groove"-shaped permanent magnet is used, and the space in the rotor 10 is accordingly set to be the through crescent groove 20.

[0049] Specifically, there are multiple through crescent grooves, and the multiple through crescent grooves are evenly distributed along the circumference of the rotor.

[0050] It should be noted that, by providing a plurality of penetrating crescent grooves 20 , the cross-sectional area of ​​the squirrel cage can be made smaller, thereby significantly improving the resistance of the squirrel cage winding.

[0051] It should also be noted that the number of the through-crescent grooves 20 is 4, and may be other numbers, but the number of through-crescent grooves 20 is not limited to 4. In the present application, the preferred number of through-crescent grooves 20 is 4.

[0052] Furthermore, the central angle of the circle penetrating the crescent groove is 87°, the inner arc radius of the circle penetrating the crescent groove is 61 mm, and the outer arc radius is 67 mm.

[0053] It should be noted that the central angle of the circle penetrating the crescent groove 20 can be 87° or other degrees, that is, the central angle of the circle penetrating the crescent groove 20 is not limited to 87°. Because the volume of the permanent magnet is fixed and the rotor length is fixed, the area required to be slotted on the rotor surface is fixed. 87° is the preferred value to ensure mechanical strength. During the design process, the volume of the permanent magnet is calculated according to an empirical formula, and the size of the crescent groove 20 is then determined based on this volume to achieve installation of the permanent magnet in the rotor 10.

[0054] It should also be noted that the inner arc radius and the outer arc radius that pass through the crescent groove 20 can also be other values. The inner arc radius is not limited to 60.8 mm, and the outer arc radius is not limited to 67 mm.

[0055] Furthermore, based on the above disclosed method for manufacturing a remanufactured motor with an unequal air gap crescent-shaped structure, during the execution of step S2, the specific execution process of step S2 is as follows:

[0056] Permanent magnets and insulating materials are placed in the rotor space, and the insulating materials are spaced between the rotor space and the permanent magnets, so that the permanent magnets form a skewed pole state.

[0057] It should be noted that the pole skewed configuration is one of the most effective and widely used methods for suppressing cogging torque ripple. This method is primarily used in motors with a large number of stator slots and an axially long length. Practice has shown that slot skew reduces the amplitude of all harmonics of the motor's electromagnetic torque. However, the chordalization of the winding back EMF caused by slot or pole skew increases electromagnetic torque ripple.

[0058] It should also be noted that in order to prevent the oblique pole state formed by the permanent magnet 30 in the crescent groove 20 from being destroyed, insulating material is needed to fill the gap in the crescent groove 20 so that the oblique pole state of the permanent magnet 30 will not be destroyed during the operation of the motor.

[0059] Furthermore, based on the above-disclosed manufacturing method of a remanufactured motor with an unequal air gap crescent-shaped structure, during the execution of step S3, the specific execution process of step S3 is: removing part of the outer circumferential surface of the rotor so that the outer circumferential surface of the rotor forms an eccentric circle, and the eccentric circle is aligned with the through crescent groove.

[0060] It should be noted that by removing part of the outer circumference of the rotor 10, an eccentric circle is formed on the outer circumference of the rotor 10, thereby forming a rotor 10 with an unequal breath structure. The eccentric circle is aligned with the through crescent groove 20, which means that the center line of the eccentric circle coincides with the center line of the through crescent groove 20. For details, please refer to Figure 2 .

[0061] Specifically, the center of the eccentric circle is offset 9.82 mm radially outward from the center of the rotor, and the radius of the eccentric circle is 74.48 mm.

[0062] Furthermore, after executing step S3, the following steps are further included:

[0063] S4. Covering the outer periphery of the rotor with a magnetic isolation sleeve.

[0064] It should be noted that the reference Figure 5 By covering the outer periphery of the rotor 10 with the magnetic isolation sleeve 40, the magnetism of the magnet 30 can be prevented from being reduced, and the service life of the magnet 30 can be increased, thereby increasing the service life of the motor.

[0065] Furthermore, after executing step S4, the following steps are also included:

[0066] S5. Install the remanufactured rotor 10 and other parts of the motor.

[0067] It should be noted that by installing the remanufactured rotor 10 with other parts of the motor, the motor becomes an operational whole.

[0068] Based on the manufacturing method of a remanufactured motor with a crescent-shaped structure having unequal air gaps provided in the above embodiment, the present invention also provides a remanufactured motor with a crescent-shaped structure having unequal air gaps, Figures 2 to 5 , the remanufactured motor with an unequal air gap crescent-shaped structure comprises: a rotor 10;

[0069] The rotor 10 is provided with a through crescent groove 20 with the axis as the centerline, and the through crescent groove 20 opens toward the axis of the rotor 10;

[0070] The outer circumference of the rotor 10 has an eccentric circle, the center of which is radially offset outward from the center of the rotor 10 ; the eccentric circle is aligned with the through crescent groove 20 .

[0071] It should be noted that a crescent slot 20 is provided on the rotor 10 with the axis as the center line, so that the squirrel cage cross-sectional area of ​​the rotor 10 is reduced and the squirrel cage winding resistance is increased, thereby enabling the modified induction motor to generate a higher starting torque than the original induction motor. The outer peripheral surface of the rotor 10 is designed as an eccentric circle, so that the rotor 10 has an unequal air gap structure, which can reduce the motor back electromotive force harmonic content and the cogging torque.

[0072] Specifically, the central angle of the circle penetrating the crescent groove 20 is 85°-87°, the inner arc radius of the circle penetrating the crescent groove 20 is 61 mm, and the outer arc radius is 67 mm.

[0073] It should be noted that the central angle of the circle penetrating the crescent groove 20 can be 87° or other degrees, that is, the central angle of the circle penetrating the crescent groove 20 is not limited to 87°. Because the volume of the permanent magnet and the length of the rotor 10 are fixed, the area of ​​the slots required on the surface of the rotor 10 is also fixed. 87° is the preferred value to ensure mechanical strength.

[0074] It should also be noted that, during the design process, the volume of the permanent magnet is calculated based on an empirical formula, and then the size of the crescent groove 20 is determined based on the volume to achieve installation of the permanent magnet in the rotor 10 .

[0075] It is worth noting that the inner arc radius and outer arc radius of the crescent groove 20 of the present invention can also be other values. The inner arc radius is not limited to 60.8 mm, and the outer arc radius is not limited to 67 mm.

[0076] Furthermore, there are multiple through-cresent grooves 20 , and the multiple through-cresent grooves 20 are evenly distributed on the rotor 10 .

[0077] It should be noted that, by providing a plurality of penetrating crescent grooves 20 , the cross-sectional area of ​​the squirrel cage can be made smaller, thereby significantly improving the resistance of the squirrel cage winding.

[0078] Specifically, the number of the through crescent grooves 20 is 4, the number of the eccentric circles is 4, and the through crescent grooves 20 and the eccentric circles are arranged in a one-to-one correspondence.

[0079] It should be noted that the through crescent grooves 20 are arranged in a one-to-one correspondence with the eccentric circles, that is, a through crescent groove 20 is arranged on each eccentric circle. In the present invention, the number of the through crescent grooves 20 and the eccentric circles is 4, but it can also be other numbers. However, the number of the through crescent grooves 20 and the eccentric circles is not limited to 4. In this application, it is preferred that the number of the through crescent grooves 20 and the eccentric circles is 4.

[0080] Specifically, the center offset value of the eccentric circle relative to the center of the rotor 10 is 9.82 mm.

[0081] It should be noted that the center offset value of the eccentric circle relative to the center of the rotor 10 can be set to 9.82 mm, or it can be set to other values. Those skilled in the art can set the offset value according to their needs. The center offset value of the eccentric circle relative to the center of the rotor 10 is not limited to 9.82 mm.

[0082] Furthermore, the remanufactured motor with the unequal air gap crescent-shaped structure further includes: a magnetic steel 30 installed in the crescent groove 20 .

[0083] It should be noted that by installing permanent magnets in the crescent grooves penetrating the rotor 10 , the motor can generate sufficient air gap magnetic field energy during operation to meet the motor operation requirements.

[0084] Specifically, there are multiple magnetic steels 30 , and the multiple magnetic steels 30 are installed in parallel in the through crescent groove 20 .

[0085] It should be noted that by installing four sets of magnets 30 in parallel along the axial direction of the rotor 10 in each of the through-crescent slots, the generated air gap magnetic field energy can be increased, thereby enabling the motor to meet operating requirements. However, the number of sets of magnets 30 is not limited to four.

[0086] Furthermore, the remanufactured motor having an unequal air gap crescent-shaped structure further comprises: an insulating material;

[0087] The permanent magnet and the insulating material are installed in the through crescent groove 20 , and the insulating material is spaced between the through crescent groove 20 and the permanent magnet, so that the permanent magnet forms a skew polarity state.

[0088] It should be noted that the pole skewed configuration is one of the most effective and widely used methods for suppressing cogging torque ripple. This method is primarily used for motors with a large number of stator slots and an axially long length. Practice has shown that slot skew reduces the amplitude of all harmonics of the motor's electromagnetic torque. However, the chordalization of the winding back EMF caused by slot or pole skew increases electromagnetic torque ripple.

[0089] It should also be noted that in order to prevent the oblique pole state formed by the permanent magnet in the crescent groove from being destroyed, insulating material is needed to fill the gap in the crescent groove so that the oblique pole state of the permanent magnet will not be destroyed during the operation of the motor.

[0090] Specifically, the permanent magnet is a magnet group, and four magnet groups are installed in each space of the rotor 10. Two adjacent magnet groups are staggered by 5° along the axial direction of the rotor 10. The magnet group is composed of two magnets 30 arranged side by side.

[0091] It should be noted that by installing 4 magnet groups in each rotor 10 space, the adjacent magnet groups are staggered 5° along the axial direction of the rotor 10, with a total tilt of 15° (see Figure 4 ).

[0092] It should also be noted that the magnetic steel group is composed of two magnetic steels 30 arranged end to end.

[0093] Furthermore, the remanufactured motor with the unequal air gap crescent-shaped structure further includes a magnetic isolation sleeve 40 for covering the silicon steel sheets of the rotor 10 .

[0094] It should be noted that, by covering the outer periphery of the rotor 10 with the magnetic isolation sleeve 40 , the magnetism of the magnet 30 can be prevented from being reduced, thereby increasing the service life of the magnet 30 and thus increasing the service life of the motor.

[0095] In order to understand the above technical solution, refer to Figures 1 to 9 , the following is a further introduction to this solution.

[0096] The present invention addresses the low efficiency of existing three-phase asynchronous motors. By redesigning the motor rotor structure, the inefficient induction motor is remanufactured into a high-efficiency asynchronous starting permanent magnet synchronous motor. By considering the rotor's cross-sectional area, a portion of the original cage is axially removed from the discarded induction motor rotor, freeing up a certain amount of rotor space for the permanent magnets. This allows the rotor to generate sufficient air gap magnetic field energy to meet the motor's operating requirements. Furthermore, considering the impact of back-EMF harmonics on the motor's efficiency, the design employs an unequal air gap structure to reduce the motor's back-EMF harmonic content and cogging torque. By axially removing a portion of the original cage and retaining a portion of the cage, the cage's cross-sectional area is reduced, significantly increasing the cage winding resistance and enabling the generation of higher starting torque compared to the original induction motor.

[0097] The present invention is based on the remanufacturing of Y2-160-4, 15KW, three-phase asynchronous motor.

[0098] The specific remanufacturing is divided into the following steps:

[0099] 1. Identify the quality of the scrap motor, then clean and disassemble it, remove the rotor before remanufacturing, retain the original stator winding, end cover and other parts, and replace the damaged parts.

[0100] 2. In order to maximize the permanent magnet area (axial direction), a "crescent arc" shaped permanent magnet is used. The volume of the permanent magnet is calculated by the equivalent ampere-turn method. The topology of the rotor is designed by combining mechanical strength and heat dissipation. With the rotor axis as the center line, a crescent groove with a central angle of 87°, an inner arc radius of 61mm, and an outer arc radius of 67mm is cut out (such as Figure 2 As shown in the figure, in order to reduce the back EMF harmonic content of the motor after remanufacturing, an eccentric circle with equal diameter is used, which is offset by 9.82 mm in the positive and negative directions along the X and Y axes respectively, and the radius of the eccentric circle is 74.48 mm.

[0101] 3. Use light insulating material strips to create a skewed pole state. Install magnets (N35SH) in the crescent groove. The magnet thickness is 6mm, the magnet arc is 35°, the outer arc radius is 67mm, and the inner arc radius is 61mm. Two magnets are arranged side by side along the circumference and four magnets are arranged side by side along the axial direction of the motor shaft. The magnets are staggered 5° in sequence along the axial direction of the motor shaft, with a total slant of 15° (e.g. Figures 3 and 4 As shown in Figure 2); Due to the processing of cutting off part of the silicon steel sheets on the rotor, the surface is covered with a magnetic shield (as shown in Figure 2); Figure 5 shown).

[0102] 4. Install the remanufactured rotor and other parts of the motor without using glue or potting.

[0103] 5. Motor performance analysis: Figure 6 is the no-load back electromotive force; Figure 7 is the starting torque; Figure 8 is the load induced voltage; Figure 9 is the air gap magnetic density map.

[0104] The key points and protection points of the present invention.

[0105] The motor rotor of this invention features a topological structure that reconstructs the theoretical design of the "cage" induction motor. Taking into account the impact of back-EMF harmonics on motor efficiency, the design employs an unequal air gap structure to reduce the back-EMF harmonic content. After permanent magnetization and remanufacturing, the starting and running functions of the original induction motor's cage are "decoupled" within the original unified cage, retaining only the starting function. This allows for partial cage removal, resolving the conflict between the starting cage and permanent magnet poles in the rotor's spatial arrangement in a self-starting permanent magnet motor.

[0106] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0107] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0108] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for manufacturing a remanufactured motor having a crescent-shaped structure with unequal air gaps, characterized in that: Including steps: Removing part of the rotor cage to release a certain amount of rotor space, including: cutting a through crescent groove with the rotor axis as the center line, with the opening of the through crescent groove facing the rotor axis; The method of installing a permanent magnet in the rotor space comprises: installing a permanent magnet and an insulating material in the rotor space, wherein the insulating material is spaced between the rotor space and the permanent magnet so that the permanent magnet forms a skewed pole state; Part of the outer circumference of the rotor is removed to make the rotor into an unequal air gap structure.

2. The manufacturing method according to claim 1, characterized in that There are multiple through-crescent grooves, and the multiple through-crescent grooves are evenly distributed along the circumference of the rotor.

3. The manufacturing method according to claim 1, characterized in that The central angle of the circle penetrating the crescent groove is 87°, the inner arc radius of the circle penetrating the crescent groove is 61 mm, and the outer arc radius is 67 mm.

4. The manufacturing method according to claim 1, characterized in that The step of removing part of the outer circumference of the rotor to form the rotor into an unequal air gap structure comprises: Part of the outer circumference of the rotor is removed to form an eccentric circle on the outer circumference of the rotor, and the eccentric circle is aligned with the through crescent groove.

5. The manufacturing method according to claim 4, characterized in that The center of the eccentric circle is offset 9.82 mm radially outward from the center of the rotor, and the radius of the eccentric circle is 74.48 mm.

6. The manufacturing method according to claim 1, characterized in that After removing part of the outer circumference of the rotor to make the rotor into an unequal air gap structure, the method further includes: The outer periphery of the rotor is covered with a magnetic isolation sleeve.

7. The manufacturing method according to claim 6, characterized in that After the outer periphery of the rotor is covered with a magnetic isolation sleeve, the invention further comprises: The remanufactured rotor is installed with other parts of the motor.

8. A remanufactured motor with a crescent-shaped structure having unequal air gaps, characterized in that: A remanufactured motor with an unequal air gap crescent-shaped structure manufactured according to the manufacturing method according to any one of claims 1 to 7.

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