Large-caliber low-magnetic-resistance-moment online balance structure and balance method

Abstract

The invention relates to a large-caliber low-magnetic-resistance-moment on-line balance structure which comprises an assembling and disassembling mechanism, a stator, a rotor and a shafting supporting mechanism, the assembling and disassembling mechanism is installed on the stator, and the rotor is connected with the shafting supporting mechanism through a rotor connecting base after the stator is embedded in the rotor; the stator comprises a stator iron core assembly, a stator shell and a stator fixing frame, the stator iron core assembly comprises a stator magnetic conducting ring and an iron core positioning block, the stator magnetic conducting ring provided with the iron core positioning block is clamped in the stator shell, and the stator shell is clamped on the stator fixing frame; the stator housing and the stator fixing frame are respectively provided with a stator housing processing gap and a stator fixing frame processing gap which are used for adjusting the stator magnetic conductive ring. The balance structure adjusts the stator magnetic conductive ring through a stator shell processing gap and a stator fixing frame processing gap, so that the magnetic resistance moment reaches a uniform condition in a 360-degree circumferential range. According to the balancing method, effective control over the magnetic resistance torque is achieved, generation of torque pulsation and noise is restrained, and therefore the overall performance and the survival rate of the motor are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of torque motors, and in particular to a large-caliber low magnetic drag torque online balancing structure and a balancing method. Background Art

[0002] The stator core is an important magnetic conductive component of the motor stator. Its internal magnetic conductive material can effectively guide the magnetic flux to gather in the air gap area to form a strong magnetic field. However, since the magnetic lines of force between the stator and rotor air gap of the motor follow the path with the smallest magnetic resistance to shorten their own length, unbalanced magnetic pull will be generated between the stator and rotor, and the magnetic permeability of the magnetic conductive material in the air is uneven; when the air gap magnetic field is evenly distributed, the magnetic pull at each radial point of the rotor is balanced, and the resultant force is zero; when the radial points of the rotor are unevenly stressed due to electromagnetic or mechanical reasons, it will cause uneven magnetic resistance torque, which will directly affect the dynamic response and mechanical performance of the motor. The relative relationship between coercive force and torque is as follows:

[0003] B r =u r ·H c ………………………………(1)

[0004]

[0005] Where:

[0006] B r - Remanence (T);

[0007] H c - Coercive force (A / m);

[0008] u r -Relative magnetic permeability (H / m);

[0009] T-torque (N / m);

[0010] N-total number of conductors;

[0011] B-air gap magnetic flux density (T);

[0012] S-permanent magnet cross-sectional area (mm2);

[0013] I-current (A);

[0014] a-number of parallel branch pairs;

[0015] p - number of pole pairs;

[0016] From equations (1) and (2), we can get the remanence B r and coercivity H cThe larger the residual magnetism, the larger the working point of the permanent magnet, the larger the air gap flux density, and the greater the torque of the motor. When the power is off, the more uneven the coercive force of the motor at different positions, the greater the difference in the motor's reluctance torque, that is, the phenomenon of uneven reluctance torque, which leads to torque pulsation and noise, and reduces the overall performance and survival rate of the motor.

[0017] Normally, small-diameter limited torque motors rarely have uneven coercivity. Large-diameter limited torque motors, due to their large outer diameter, thick axial dimensions, and the use of an integral core structure, are prone to uneven coercivity in soft magnetic materials after heat treatment.

[0018] Aiming at the above-mentioned uneven magnetic drag torque phenomenon, a large-caliber low magnetic drag torque online balancing structure and balancing method are proposed. Summary of the invention

[0019] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a large-caliber low magnetic drag torque online balancing structure. The stator magnetic ring is adjusted by machining notches in the stator shell and the stator fixing frame, and the local large points of the magnetic drag torque are screened out, so that the magnetic drag torque reaches a uniform condition within a 360° circumference.

[0020] The present invention also proposes a balancing method for a large-caliber low reluctance torque online balancing structure to achieve effective control of the reluctance torque, solve the problem of uneven reluctance torque, suppress the generation of torque pulsation and noise, and thus improve the overall performance and survival rate of the motor.

[0021] The present invention solves the technical problem by the following technical solutions:

[0022] A large-caliber low magnetic drag torque online balancing structure, comprising an assembly and disassembly mechanism, a stator, a rotor and a shaft support mechanism, wherein the assembly and disassembly mechanism is mounted on the stator, the stator is embedded with a rotor, and the rotor is connected to the shaft support mechanism through a rotor connecting seat;

[0023] The stator comprises a stator core assembly, a stator shell and a stator fixing frame. The stator core assembly comprises a stator magnetic ring and a core positioning block. The stator magnetic ring equipped with the core positioning block is clamped in the stator shell. The stator shell is clamped on the stator fixing frame. The stator shell and the stator fixing frame are respectively provided with a stator shell machining notch for adjusting the stator magnetic ring and a stator fixing frame machining notch.

[0024] Furthermore, the assembly and disassembly mechanism includes an assembly and disassembly bracket and a screw rod, the upper cross bar of the assembly and disassembly bracket is connected to the upper end of the screw rod, the lower ring of the assembly and disassembly bracket is installed on the upper end of the stator fixing frame, and the lower end of the screw rod is connected to the stator housing through a threaded connection seat.

[0025] Furthermore, a shaft positioning hole is formed inside the screw.

[0026] Furthermore, the shaft support mechanism includes a shaft, a bearing seat, a bearing assembly and a support base. The upper end of the shaft is installed on the assembly and disassembly mechanism, the middle part of the shaft is located at the lower end of the rotor connecting seat, the lower end of the shaft is installed in the bearing seat through the bearing assembly, and the bearing seat is installed on the support base.

[0027] Furthermore, the bearing assembly includes bearing 1, a pressure plate, a lock nut, an inner pressure ring, an outer pressure ring and bearing 2. Bearing 1 and bearing 2 are located at the lower end of the shaft. An inner pressure ring and an outer pressure ring are respectively installed between bearing 1 and bearing 2. The pressure plate is located at the upper end of the bearing seat to clamp bearing 2 in the bearing seat. The lock nut is located at the lower end of the bearing to lock bearing 1 to the shaft.

[0028] A balancing method for a large-caliber low magnetic drag torque online balancing structure comprises the following steps:

[0029] Step 1: Place the assembled large-caliber low magnetic drag torque online balancing structure on a workbench;

[0030] Step 2: Screw the screw of the assembly and disassembly mechanism to drive the screw connecting seat to move upward to expose the rotor;

[0031] Step 3: Manually rotate the rotor, and the rotor is screened online within 360° of the uniformity and condition of the magnetic resistance torque at each position of the stator under the action of the shaft support mechanism;

[0032] Step 4: If there is an uneven magnetic resistance torque, the rotor will rebound at a certain angle, that is, the rotor cannot stay at a certain position within 360° for a moment;

[0033] Step 5: Adjust the relative position of the stator magnetic ring through the machining gap of the stator housing and the machining gap of the stator fixing frame to make the magnetic resistance torque reach a uniform condition;

[0034] Step 6, repeating steps 5 and 6, online screening the uniformity and condition of the magnetic drag torque at each position of the stator within a range of 360°, adjusting the relative position of the stator magnetic conductive ring through the machining gap of the stator shell and the machining gap of the stator fixing frame, so that the magnetic drag torque reaches a uniform condition;

[0035] Step 7: The screw connecting seat is driven downward by screwing the screw of the assembly and disassembly mechanism to close the rotor and the stator;

[0036] Complete online balancing of large-caliber low magnetic drag torque.

[0037] The advantages and positive effects of the present invention are:

[0038] 1. The large-caliber low magnetic drag torque online balancing structure of the present invention has a stator magnetic ring which is composed of a number of magnetic rings of equal thickness and size, replacing an integral ring structure, thereby reducing the occurrence of uneven coercive force caused by materials or heat treatment processes. The magnetic drag torque can be dynamically balanced by directly adjusting the positional relationship between the stator magnetic rings.

[0039] 2. The large-caliber low magnetic drag torque online balancing structure of the present invention has a stator shell and a stator fixing frame respectively provided with a stator shell processing notch and a stator fixing frame processing notch for adjusting the stator magnetic conductive ring. There is a mechanical gap between the stator magnetic conductive ring and the core positioning block. The relative position of the stator magnetic conductive ring is adjusted by the stator shell processing notch and the stator fixing frame processing notch to screen out local large points of the magnetic drag torque, so that the magnetic drag torque reaches a uniform condition within a 360° circumference.

[0040] 3. The large-caliber low magnetic drag torque online balancing structure of the present invention includes an assembly and disassembly bracket and a screw. By rotating the screw, the screw connecting seat is driven to move upward. There is no need to completely disassemble the stator and the rotor, and the magnetic drag torque uniformity and change of the rotor within 360° on the shaft support mechanism can be screened.

[0041] 4. The large-caliber low reluctance torque online balancing structure of the present invention has a shaft support mechanism including a shaft, a bearing seat, a bearing assembly and a support base. The shaft support mechanism has a 360° rotation feature. By slowly rotating the rotor manually, the uniformity and change of the reluctance torque of the stator core assembly within a 360° range can be screened. At the same time, axial and radial support are provided for the online balancing of the large-caliber low reluctance torque to ensure continuous rotation of the rotor.

[0042] 5. The balancing method of the large-caliber low magnetic drag torque online balancing structure of the present invention is simple and easy to operate, and does not require repeated disassembly and assembly of the stator. By screening the magnetic drag torque changes of the rotor within the circumference, the relative positions of the stator magnetic rings are balanced online to make the magnetic drag torque uniform. This method can significantly improve the survival rate of the motor while ensuring the realization of the motor performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a three-dimensional schematic diagram of the large-caliber low magnetic drag torque online balancing structure of the present invention;

[0044] Figure 2 It is a structural schematic diagram of a large-caliber low magnetic drag torque online balancing structure of the present invention;

[0045] Figure 3 for Figure 2 AA section diagram;

[0046] Figure 4It is a schematic diagram of the coordination of the stator, rotor and shaft support mechanism of the large-caliber low magnetic drag torque online balancing structure of the present invention;

[0047] Figure 5 for Figure 4 Exploded image;

[0048] Figure 6 It is a schematic diagram of a stator core assembly of a large-caliber low magnetic drag torque online balancing structure of the present invention;

[0049] Figure 7 for Figure 6 BB section diagram;

[0050] Figure 8 A curve diagram showing the relationship between the angle and the magnetic induction coercive force of the large-caliber low magnetic drag torque of the present invention before online balancing;

[0051] Fig. 9 A curve diagram showing the relationship between the angle and the magnetic induction coercive force after online balancing of the large-caliber low magnetic drag torque of the present invention;

[0052] In the figure:

[0053] 1-assembly and disassembly mechanism, 11-assembly and disassembly bracket, 12-screw, 13-axis positioning hole, 14-screw connecting seat, 2-stator, 21-stator core assembly, 22-stator magnetic ring, 23-core positioning block, 24-stator housing, 25-stator fixing frame, 26-stator housing processing notch, 27-stator fixing frame processing notch, 3-rotor, 31-rotor connecting seat, 4-axis support mechanism, 41-shaft, 42-bearing one, 43-pressure plate, 44-lock nut, 45-bearing seat, 46-support base, 47-inner pressure ring, 48-outer pressure ring, 49-bearing two. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0055] like Figures 1 to 7 As shown, a large-caliber low magnetic drag torque online balancing structure includes an assembly and disassembly mechanism 1, a stator 2, a rotor 3 and a shaft support mechanism 4, wherein the assembly and disassembly mechanism 1 is installed on the stator 2, the stator 2 is embedded with the rotor 3, and the rotor 3 is connected to the shaft support mechanism 4 via a rotor connecting seat 31.

[0056] The stator 2 includes a stator core assembly 21, a stator housing 24 and a stator fixing frame 25. The stator core assembly 21 includes a stator magnetic ring 22 and a core positioning block 23. The stator magnetic ring 22 with the core positioning block 23 is mounted in the stator housing 24. The stator housing 24 is mounted on the stator fixing frame 25. The stator housing 24 and the stator fixing frame 25 are respectively provided with a stator housing processing notch 26 and a stator fixing frame processing notch 27 for adjusting the stator magnetic ring 22. The stator magnetic ring 22 is formed by splicing a plurality of magnetic rings of equal thickness and size, and is connected by coaxial 41 of the core positioning block 23. The core positioning block 23 is used to realize axial and radial fixation. The stator magnetic ring 22 and the core positioning block 23 are clearance-matched. A threaded hole is provided at the bottom of the core positioning block 23. The stator housing 24 is connected to the stator core assembly 21 by screws. There is a mechanical gap between the stator magnetic ring 22 and the core positioning block 23. The relative position of the stator magnetic ring 22 can be adjusted by the stator shell processing notch 26 and the stator fixing frame processing notch 27 to screen out local large points of the magnetic resistance torque so that the magnetic resistance torque reaches a uniform condition within a 360° circumference.

[0057] The assembly and disassembly mechanism 1 includes an assembly and disassembly bracket 11 and a screw 12. A threaded hole is arranged at the center of the cross bar at the upper end of the assembly and disassembly bracket 11. The upper end of the screw 12 is threadedly connected to the cross bar. The lower end of the assembly and disassembly bracket 11 is clamped and installed on the upper end of the stator fixing frame 25 and fixed by screws. The lower end of the screw 12 is connected to the stator housing 24 by a threaded connection seat. An axis positioning hole 13 of a limit axis 41 is arranged inside the screw 12. By rotating the screw 12 to drive the screw connection seat 14 to move upward, the uniformity and change of the magnetic resistance torque of the rotor 3 within a range of 360° on the shaft support mechanism 4 can be screened without completely disassembling the stator 2 and the rotor 3.

[0058] The shaft support mechanism 4 includes a shaft 41, a bearing seat 45, a bearing assembly and a support base 46. The upper end of the shaft 41 is installed in the shaft positioning hole 13 of the screw 12 of the assembly and disassembly mechanism 1, and the middle part of the shaft 41 is located at the lower end of the rotor connection seat 31. The lower end of the shaft 41 is installed in the bearing seat 45 through the bearing assembly, and the bearing seat 45 is installed on the support base 46. The shaft support mechanism 4 has a 360° rotation feature. By manually rotating the rotor 3 slowly, the uniformity and change of the magnetic drag torque of the stator core assembly 21 within the range of 360° are screened, and at the same time, axial and radial support are provided for the online balance of large-caliber low magnetic drag torque to ensure that the rotor 3 can achieve continuous rotation.

[0059] The bearing assembly includes a bearing 1 42, a pressure plate 43, a lock nut 44, an inner pressure ring 47, an outer pressure ring 48 and a bearing 2 49. The bearing 1 42 and the bearing 2 49 are located at the lower end of the shaft 41. The inner pressure ring 47 and the outer pressure ring 48 are respectively installed between the bearing 1 42 and the bearing 2 49. The pressure plate 43 is located at the upper end of the bearing seat 45, and the bearing 2 49 is clamped in the bearing seat 45. The lock nut 44 is located at the lower end of the bearing 1 42 to lock the bearing 1 42 and the shaft.

[0060] Working principle of the present invention:

[0061] The shaft 41 is installed on the bearing seat 45 through the bearing assembly, and the bearing seat 45 is installed on the supporting base 46; the stator fixing frame 25 is installed on the upper end of the bearing seat 45, the stator housing 24 is installed in the stator fixing frame 25, the stator core assembly 21 is installed in the stator housing 24, and the stator core assembly 21 is threadedly connected with the stator housing 24 through the threaded hole set at the bottom end of the core positioning block 23 to form a stator 2; the stator 2 is embedded with the rotor 3, and the rotor 3 is coaxially installed with the shaft 41 through the rotor connecting seat 31; the upper end of the screw rod 12 is threadedly connected with the threaded hole provided at the center of the cross bar at the upper end of the assembly and disassembly bracket 11, and the lower end of the screw rod 12 is connected to the stator housing 24 through a threaded connecting seat, and the upper end of the shaft 41 is located in the shaft positioning hole 13 of the limiting shaft 41 provided inside the screw rod 12, and then the lower end of the assembly and disassembly bracket 11 is clamped and installed on the upper end of the stator fixing frame 25 and fixed by screws.

[0062] When using a large-caliber low magnetic drag torque online balancing structure, the screw connecting seat 14 is driven upward by screwing the screw 12 to expose the rotor 3. There is no need to completely disassemble the stator 2 and the rotor 3. The rotor 3 is manually rotated. Under the action of the shaft support mechanism 4, the rotor 3 is online screened for the uniformity and condition of the magnetic drag torque at various positions of the stator 2 within a 360° range. If there is an uneven magnetic drag torque position, the rotor 3 will rebound at a certain angle, that is, the rotor 3 cannot stay at a certain position within 360° for an instant. The relative position of the stator magnetic conductive ring 22 is adjusted by the stator shell machining notch 26 and the stator fixing frame machining notch 27 to make the magnetic drag torque reach a uniform condition. The screw connecting seat 14 is driven downward by screwing the screw 12 of the assembly and disassembly mechanism 1 to close the rotor 3 and the stator 2, and complete the large-caliber low magnetic drag torque online balancing.

[0063] The present invention provides a large-caliber low magnetic drag torque online balancing structure. It does not need to repeatedly disassemble and assemble the structure. The stator magnetic conductive ring 22 is directly adjusted through the stator shell processing notch 26 and the stator fixing frame processing notch 27 to adjust the relative position of the stator magnetic conductive ring 22, thereby weakening the magnetic drag torque, screening out local large points of the magnetic drag torque, and making the magnetic drag torque reach a uniform condition within a 360° circumference, thereby ultimately improving the survival rate of the motor.

[0064] A balancing method for a large-caliber low magnetic drag torque online balancing structure comprises the following steps:

[0065] Step 1: Place the assembled large-caliber low magnetic drag torque online balancing structure on a workbench;

[0066] Step 2: The screw rod 12 of the assembly and disassembly mechanism 1 is screwed to drive the screw rod connecting seat 14 to move upward, exposing the rotor 3;

[0067] Step 3, manually rotating the rotor 3, the rotor 3 is online screened within 360° of the uniformity and condition of the magnetic drag torque at each position of the stator 2 under the action of the shaft support mechanism 4;

[0068] Step 4: If there is an uneven magnetic resistance torque position, the rotor 3 will rebound at a certain angle, that is, the rotor 3 cannot stay at a certain position within 360° for a moment;

[0069] Step 5: Adjust the relative position of the stator magnetic ring 22 through the stator housing processing notch 26 and the stator fixing frame processing notch 27 to make the magnetic resistance torque reach a uniform condition;

[0070] Step 6, repeating steps 5 and 6, online screening the uniformity and condition of the magnetic drag torque at each position of the stator 2 within a range of 360°, adjusting the relative position of the stator magnetic conductive ring 22 through the stator housing machining notch 26 and the stator fixing frame machining notch 27, so that the magnetic drag torque reaches a uniform condition;

[0071] Step 7, drive the screw connecting seat 14 downward by screwing the screw 12 of the assembly and disassembly mechanism 1 to close the rotor 3 and the stator 2;

[0072] Complete online balancing of large-caliber low magnetic drag torque.

[0073] The stator housing 24 and the stator fixing frame 25 are respectively provided with a stator housing machining notch 26 and a stator fixing frame machining notch 27, so that there is sufficient operating space for manual operation. There is a mechanical gap between the stator magnetic ring 22 and the core positioning block 23. The shaft support mechanism 4 has a 360° rotation feature. By manually rotating the rotor 3 slowly, the uniformity and change of the magnetic drag torque of the stator core assembly 21 within the range of 360° are screened; if there are uneven points, the relative position between the stator magnetic ring 22 is adjusted through the stator housing machining notch 26 and the stator fixing frame machining notch 27 to remove the local large points of the magnetic drag torque, so that the magnetic drag torque reaches a uniform condition within the 360° circumference. The balancing method of the large-caliber low magnetic drag torque online balancing structure avoids the adverse effects caused by repeated disassembly and assembly, and the uneven points of the magnetic drag torque are equalized through gradual adjustment until the requirements are met.

[0074] from Figure 8 and Fig. 9It can be seen that the balancing method using a large-diameter low reluctance torque online balancing structure can reduce the reluctance torque from a maximum value of 15A / m to 4A / m (average) through online balancing, thereby achieving the effect of equalizing the reluctance torque within the circumference and improving the survival rate of the motor.

[0075] The present invention discloses a balancing method for a large-caliber low reluctance torque online balancing structure, which realizes effective control of the reluctance torque, solves the problem of uneven reluctance torque, suppresses the occurrence of uneven reluctance torque, and suppresses the generation of torque pulsation and noise, thereby improving the overall performance and survival rate of the motor.

[0076] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A large-caliber low magnetic drag torque online balancing structure, characterized in that: The invention comprises an assembly and disassembly mechanism (1), a stator (2), a rotor (3) and a shaft support mechanism (4), wherein the assembly and disassembly mechanism (1) is mounted on the stator (2), the stator (2) is embedded with the rotor (3), and the rotor (3) and the shaft support mechanism (4) are connected via a rotor connection seat (31); The stator (2) comprises a stator core assembly (21), a stator housing (24) and a stator fixing frame (25); the stator core assembly (21) comprises a stator magnetic ring (22) and a core positioning block (23); the stator magnetic ring (22) equipped with the core positioning block (23) is clamped in the stator housing (24); the stator housing (24) is clamped on the stator fixing frame (25); the stator housing (24) and the stator fixing frame (25) are respectively provided with a stator housing stator housing machining notch (26) and a stator fixing frame machining notch (27) for adjusting the stator magnetic ring (22).

2. The large-caliber low magnetic drag torque online balancing structure according to claim 1 is characterized in that: The assembly and disassembly mechanism (1) comprises an assembly and disassembly bracket (11) and a screw rod (12); a cross bar at the upper end of the assembly and disassembly bracket (11) is connected to the upper end of the screw rod (12); a circular ring at the lower end of the assembly and disassembly bracket (11) is mounted on the upper end of a stator fixing frame (25); and a lower end of the screw rod (12) is connected to a stator housing (24) via a threaded connection seat.

3. The large-caliber low magnetic drag torque online balancing structure according to claim 2 is characterized in that: The screw rod (12) is provided with an axis positioning hole (13) inside.

4. The large-caliber low magnetic drag torque online balancing structure according to claim 1 is characterized in that: The shaft support mechanism (4) comprises a shaft (41), a bearing seat (45), a bearing assembly and a support base (46); the upper end of the shaft (41) is mounted on the assembly and disassembly mechanism (1); the middle of the shaft (41) is located at the lower end of the rotor connecting seat (31); the lower end of the shaft (41) is mounted in the bearing seat (45) through the bearing assembly; and the bearing seat (45) is mounted on the support base (46).

5. The large-caliber low magnetic drag torque online balancing structure according to claim 4 is characterized in that: The bearing assembly comprises a bearing 1 (42), a pressure plate (43), a lock nut (44), an inner pressure ring (47), an outer pressure ring (48) and a bearing 2 (49); the bearing 1 (42) and the bearing 2 (49) are located at the lower end of the shaft (41); an inner pressure ring (47) and an outer pressure ring (48) are respectively installed between the bearing 1 (42) and the bearing 2 (49); the pressure plate (43) is located at the upper end of the bearing seat (45) to clamp the bearing 2 (49) in the bearing seat (45); the lock nut (44) is located at the lower end of the bearing 1 (42) to lock the bearing 1 (42) and the shaft.

6. A balancing method for a large-caliber low magnetic drag torque online balancing structure as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Place the assembled large-caliber low magnetic drag torque online balancing structure on a workbench; Step 2: Screw the screw of the assembly and disassembly mechanism to drive the screw connecting seat to move upward to expose the rotor; Step 3: Manually rotate the rotor, and the rotor is screened online within 360° of the uniformity and condition of the magnetic resistance torque at each position of the stator under the action of the shaft support mechanism; Step 4: If there is an uneven magnetic resistance torque, the rotor will rebound at a certain angle, that is, the rotor cannot stay at a certain position within 360° for a moment; Step 5: Adjust the relative position of the stator magnetic ring through the machining gap of the stator housing and the machining gap of the stator fixing frame to make the magnetic resistance torque reach a uniform condition; Step 6, repeating steps 5 and 6, online screening the uniformity and condition of the magnetic drag torque at each position of the stator within a range of 360°, adjusting the relative position of the stator magnetic conductive ring through the machining gap of the stator shell and the machining gap of the stator fixing frame, so that the magnetic drag torque reaches a uniform condition; Step 7: The screw connecting seat is driven downward by screwing the screw of the assembly and disassembly mechanism to close the rotor and the stator; Complete online balancing of large-caliber low magnetic drag torque.

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