A double-direction multi-cell distributed arc line permanent magnet synchronous motor with a shaft

Abstract

The application relates to the technical field of permanent magnet synchronous motors and provides a week-axis bidirectional multi-unit distributed arc line permanent magnet synchronous motor which comprises a segmented stator assembly, a coaxial rotor assembly and an armature winding; the coaxial rotor assembly comprises a rotor shaft, a rotor yoke, rotor teeth and rotor radial permanent magnets which are alternately distributed along the outer periphery of the rotor yoke; a front rotor section and a rear rotor section are arranged with a difference of half a rotor pole pitch in the circumferential direction, a front stator area and a rear stator area have no relative displacement in the circumferential direction, the armature winding is a concentrated cross winding shared by a front motor unit and a rear motor unit, and the armature winding is connected in series to form a bidirectional complementary structure combining circumferential distribution and axial staggering. The application has the effects of improving the effective magnetic field strength at the arc-shaped air gap and the average output torque.

Description

Technical Field

[0001] This invention relates to the technical field of permanent magnet synchronous motors, specifically to a circumferential axis bidirectional multi-unit distributed arc permanent magnet synchronous motor. Background Technology

[0002] Large vertical lathes are used for machining ultra-large, ultra-heavy, and high-precision critical components. Their workpiece turntables typically need to withstand large-diameter workpieces, heavy inertia, and cutting impact loads. The driving performance of the workpiece turntable directly affects the rotational accuracy, speed stability, and disturbance resistance during machining. Therefore, the drive motor is required to have low-speed high torque, smooth output, high structural rigidity, strong load-bearing capacity, and long-term reliable operation.

[0003] In existing large rotary table drive solutions, indirect drive methods typically require the motor output to be transmitted to the rotary table via gears, worm gears, reduction mechanisms, or other transmission chains. While this type of method can amplify the output torque through mechanical transmission, the transmission chain is long and prone to backlash, wear, transmission errors, and elastic deformation. Under heavy-load cutting or low-speed feed conditions, this can easily affect the rotary table's positioning accuracy and speed stability, making it difficult to meet the high-precision machining requirements of high-end large vertical lathes.

[0004] To reduce mechanical transmission errors, existing technologies also employ integrated centralized direct-drive motors to drive the rotary table. While this structure can shorten the transmission chain, in large vertical lathe scenarios, the rotary table diameter is large. Using a complete annular stator or a centralized large-diameter motor structure would significantly increase the difficulty of stator manufacturing, transportation, assembly, and maintenance. Furthermore, large-diameter flat motor structures are susceptible to insufficient structural rigidity, assembly errors, and difficulties in maintaining the air gap under heavy-load cutting impacts, leading to vibration, deformation, or output torque fluctuations.

[0005] An arc motor is a special type of permanent magnet direct-drive motor that outputs torque or angular displacement along an arc path. Its stator and rotor can be arranged along concentric arcs and can be in the form of single-segment arc units or multi-segment arc unit splicing to achieve reciprocating oscillation or continuous rotation operation at a limited angle. Due to its segmented arrangement, modular expansion, and direct-drive output characteristics, the arc motor provides a feasible structural direction for direct drive of large turntables.

[0006] Existing arc-shaped permanent magnet synchronous motors generally fall into two categories: rotor permanent magnet type and stator permanent magnet type. Rotor permanent magnet arc-shaped motors typically place the permanent magnets on the rotor side and the armature windings on the stator side, offering advantages such as relatively simple control and high torque output. However, the rotor-side permanent magnets move with the rotor and are susceptible to centrifugal force, temperature rise, and mechanical stress under high-speed or impact conditions, leading to issues with permanent magnet fixation reliability, heat dissipation, demagnetization, and increased rotor inertia. Stator permanent magnet arc-shaped motors, on the other hand, usually place both the permanent magnets and windings on the stator side, with the rotor side primarily serving as a magnetic salient pole structure for magnetic conduction modulation. This type offers advantages such as a more robust rotor structure, better heat dissipation, and higher reliability, but its torque density is relatively low, its back EMF sinusoidal nature is poor, its torque ripple is large, and its control and modulation relationships are more complex.

[0007] Furthermore, traditional arc-shaped motors, due to the stator core not being a complete closed loop but possessing an arc-shaped open boundary, are prone to significant edge effects during operation. These edge effects lead to uneven distribution of the air gap magnetic field, distortion of the induced electromotive force, and fluctuations in output torque. Simultaneously, the slotted stator and rotor structures, salient pole structures, and high-pole permanent magnet structures in arc-shaped permanent magnet synchronous motors also introduce cogging effects. When the edge effects and cogging effects are superimposed, the motor is prone to increased torque pulsation, decreased speed stability, and even low-speed creeping problems at low speeds.

[0008] Chinese invention patent CN115622288A discloses a double-sided permanent magnet multi-unit modular arc permanent magnet synchronous motor, which consists of three stator units and a rotor structure. Alternating pole permanent magnets are installed on both the stator and rotor sides, and the bidirectional magnetic field modulation effect is used to improve torque density and permanent magnet utilization. Compared with a single-sided excitation structure, this scheme improves magnetic field utilization and output capacity to a certain extent. However, its tooth-end surface-mounted permanent magnets still pose risks in terms of thermal demagnetization, eddy current losses, and mechanical reliability. Furthermore, this type of structure may still be affected by the edge effect and cogging effect of arc motors, resulting in limited torque pulsation suppression capability. Therefore, it is difficult to fully meet the comprehensive requirements of large vertical lathe workpiece turntables in terms of low-speed high torque, stable speed without crawling, and heavy-load high rigidity.

[0009] Therefore, the current technology has at least the following shortcomings: First, the magnetic energy utilization rate of the single-sided permanent magnet excitation structure is limited, making it difficult to obtain a sufficiently high average output torque within a limited installation space; second, the edge effect caused by the arc-shaped stator and the cogging effect caused by the stator and rotor slots are easily superimposed, resulting in large torque pulsation; third, the traditional centralized large-diameter direct drive structure is difficult to manufacture and assemble, and has insufficient modular expansion capability; fourth, when introducing double-sided permanent magnet excitation to improve torque output, if there is a lack of an effective spatial phase complementary structure, it is still difficult to achieve both high torque density and low torque pulsation.

[0010] Based on the above problems, it is necessary to provide a circumferential bidirectional multi-unit distributed arc permanent magnet synchronous motor suitable for large vertical lathe workpiece turntables. By using segmented stator components, the manufacturing and assembly difficulty of large-diameter motors is reduced. The three-source composite excitation structure, consisting of radial permanent magnets in the stator yoke, tangential permanent magnets in the stator teeth, and radial permanent magnets in the rotor, improves the effective magnetic field strength and average output torque at the arc-shaped air gap. At the same time, the circumferential distribution of the three arc-shaped stator sub-units, the concentrated cross windings, and the axial staggered complementary structure of half the rotor pole pitch in the front and rear rotor sections reduce torque pulsation caused by edge effect and cogging effect, thereby meeting the application requirements of large vertical lathe workpiece turntables for low-speed, high-torque, smooth operation, and heavy-load, high-rigidity direct drive. Summary of the Invention

[0011] The purpose of this invention is to address the shortcomings of the aforementioned permanent magnet synchronous motors by proposing a circumferential bidirectional multi-unit distributed arc permanent magnet synchronous motor.

[0012] The present invention adopts the following technical solution: A circumferential bidirectional multi-unit distributed arc permanent magnet synchronous motor includes a segmented stator assembly, a coaxial rotor assembly, and an armature winding; The segmented stator assembly includes three arc-shaped stator sub-units arranged discontinuously along the circumferential direction. The three arc-shaped stator sub-units are distributed around the coaxial rotor assembly at a spatial interval of 120°, and an arc-shaped air gap is formed between each arc-shaped stator sub-unit and the coaxial rotor assembly. The coaxial rotor assembly includes a front rotor section and a rear rotor section arranged coaxially. The segmented stator assembly has a front stator region corresponding to the front rotor section and a rear stator region corresponding to the rear rotor section. The front stator region and the front rotor section form a front motor unit, and the rear stator region and the rear rotor section form a rear motor unit. The front stator region and the rear stator region are axially integrated stator structures, and the arc-shaped stator sub-units corresponding to the front stator region and the rear stator region have the same structure and size; Each of the arc-shaped stator subunits includes a stator yoke, a plurality of stator core main teeth, a stator slot disposed between adjacent stator core main teeth, a stator auxiliary tooth, an armature winding disposed in the stator slot, a yoke radial permanent magnet embedded in the stator yoke, and a tooth tangential permanent magnet disposed between adjacent stator core main teeth and located on both sides of the stator core main teeth; The coaxial rotor assembly includes a rotor shaft, a rotor yoke, rotor teeth and rotor radial permanent magnets that are alternately distributed along the outer periphery of the rotor yoke. The front rotor segment and the rear rotor segment are set apart by half a rotor pole pitch in the circumferential direction. The front stator region and the rear stator region have no relative displacement in the circumferential direction. The armature winding is a centralized cross winding shared by the front motor unit and the rear motor unit, and the armature windings are connected in series to form a bidirectional complementary structure that combines circumferential distribution and axial staggering.

[0013] Optionally, each of the arc-shaped stator sub-units occupies a 72° mechanical angle in the circumferential direction, and the three arc-shaped stator sub-units are distributed in a discontinuous fan shape along the circumferential direction. The coaxial rotor assembly is a cylindrical rotor structure that extends axially and passes through the inner side of the three arc-shaped stator sub-units.

[0014] Optionally, the toothed tangential permanent magnet includes a first toothed tangential permanent magnet and a second toothed tangential permanent magnet, the first toothed tangential permanent magnet and the second toothed tangential permanent magnet are alternately arranged in the circumferential direction, and the tangential magnetization directions of the first toothed tangential permanent magnet and the second toothed tangential permanent magnet are opposite, so as to form a face-to-face magnetic focusing structure between adjacent stator core main teeth.

[0015] Optionally, the radial permanent magnet of the yoke corresponding to the front rotor segment is magnetized radially outward, and the radial permanent magnet of the yoke corresponding to the rear rotor segment is magnetized radially inward, so that the radial magnetization directions of the radial permanent magnets of the yoke corresponding to the front motor unit and the rear motor unit are opposite.

[0016] Optionally, both the front rotor section and the rear rotor section include 50 rotor teeth and 50 rotor radial permanent magnets. The outer periphery of the rotor yoke is provided with non-uniform slots arranged in the circumferential direction. The rotor teeth are formed between adjacent non-uniform slots. The rotor radial permanent magnets are disposed in the slot area between adjacent rotor teeth. The rotor teeth and the rotor radial permanent magnets are arranged alternately in the circumferential direction to form a permanent magnet-rotor tooth alternating pole structure, and 50 pairs of pole structures are formed in the circumferential direction.

[0017] Optionally, the radial permanent magnets of the front rotor segment and the rear rotor segment have opposite polarities, and the circumferential misalignment angle between the front rotor segment and the rear rotor segment is a mechanical angle of 180 / 50°, so that the front motor unit and the rear motor unit are electrically 180° apart.

[0018] Optionally, the radial permanent magnet of the yoke, the tangential permanent magnet of the tooth, and the radial permanent magnet of the rotor together constitute a three-source composite excitation structure, and the three-source composite excitation structure forms a composite modulation magnetic circuit at the arc-shaped air gap.

[0019] Optionally, the stator core main teeth, the stator auxiliary teeth, the stator yoke, the rotor teeth, and the rotor magnetic yoke are all formed by stacking silicon steel sheets, and the radial permanent magnets of the yoke, the tangential permanent magnets of the teeth, and the radial permanent magnets of the rotor are all neodymium iron boron permanent magnets.

[0020] Optionally, the silicon steel sheet is a DW315_35 silicon steel sheet, the neodymium iron boron permanent magnet is an N42SH grade neodymium iron boron permanent magnet, and the rotor shaft is located at the center of the rotor yoke and is used to connect the workpiece turntable of a large vertical lathe.

[0021] The beneficial effects achieved by this invention are: I. This invention forms a segmented stator assembly by setting three arc-shaped stator sub-units arranged discontinuously along the circumferential direction and distributing these three arc-shaped stator sub-units around a coaxial rotor assembly at 120° spatial intervals. Compared to a large-diameter integrated annular stator structure, this segmented stator assembly can reduce the difficulty of manufacturing, transporting, assembling, and maintaining large direct-drive motors, and can be modularly arranged according to the diameter and load requirements of large vertical lathe workpiece turntables, thereby improving the structural adaptability and engineering implementation convenience of the motor in large-diameter, heavy-load turntable scenarios.

[0022] II. This invention utilizes a three-source composite excitation structure comprised of radial permanent magnets in the yoke, tangential permanent magnets in the teeth, and radial permanent magnets in the rotor. This allows the radial excitation of the stator yoke, the tangential magnetic focusing excitation of the stator teeth, and the radial excitation of the rotor to work together on the arc-shaped air gap. The tangential permanent magnets in the teeth can form a face-to-face magnetic focusing structure between adjacent stator core main teeth, concentrating the magnetic flux from the stator and rotor sides into the arc-shaped air gap region, thereby increasing the effective magnetic field strength and effective operating harmonic amplitude at the arc-shaped air gap. This improves upon the low magnetic energy utilization and limited torque density improvement potential of traditional single-sided permanent magnet arc motors, increasing the average output torque of the motor.

[0023] III. The coaxial rotor assembly of the present invention includes a front rotor section and a rear rotor section arranged coaxially. The front rotor section and the rear rotor section are separated by half a rotor pole pitch in the circumferential direction, and the front stator region and the rear stator region have no relative displacement in the circumferential direction. Through this axially parallel and circumferentially staggered arrangement, the cogging torque and edge torque generated by the front motor unit and the rear motor unit can complement each other in phase, canceling torque pulsation from a structural level. This improves the problems of large low-speed torque fluctuation, poor speed stability, and low-speed creep caused by the superposition of edge effect and cogging effect in traditional arc motors.

[0024] Fourth, the armature winding of the present invention is a centralized cross winding shared by the front motor unit and the rear motor unit, and the armature windings are connected in series. This centralized cross winding enables different phase windings to form a cross distribution in the circumferential spatial position of the arc-shaped stator sub-unit, and performs electromagnetic symmetry compensation for the induced electromotive force distortion caused by the arc-shaped stator break boundary, thereby suppressing the parasitic torque caused by the edge effect and current harmonics, and improving the output smoothness of the motor in low-speed operation.

[0025] V. Both the front and rear rotor sections of this invention include 50 rotor teeth and 50 rotor radial permanent magnets. The rotor teeth and rotor radial permanent magnets are alternately arranged along the circumference to form an alternating pole structure of "permanent magnet-rotor tooth", forming 50 pairs of poles in the circumferential direction. This structure can reduce the number of permanent magnets used while ensuring high pole number magnetic field modulation capability, improve the utilization rate of permanent magnets, and help reduce the material cost and structural burden caused by the arrangement of permanent magnets on the rotor side.

[0026] VI. In this invention, the radial permanent magnets of the yoke corresponding to the front rotor segment are magnetized radially outward, while the radial permanent magnets of the yoke corresponding to the rear rotor segment are magnetized radially inward. Simultaneously, the polarities of the rotor radial permanent magnets in the front and rear rotor segments are opposite. Through the corresponding arrangement of the permanent magnet polarities and spatial phases of the front and rear motor units, a bidirectional complementary magnetic field modulation relationship along the circumferential axis can be formed. This enables the front and rear motor units to achieve average torque superposition and pulsation component cancellation when outputting coaxially, thus balancing high torque output and low torque pulsation.

[0027] VII. In this invention, the stator core main teeth, stator auxiliary teeth, stator yoke, rotor teeth, and rotor magnetic yoke are all formed by stacking silicon steel sheets. The radial permanent magnets of the yoke, the tangential permanent magnets of the teeth, and the radial permanent magnets of the rotor are all neodymium iron boron permanent magnets. This material configuration is beneficial for improving magnetic conductivity and permanent magnet excitation capability, enabling the motor to maintain high electromagnetic stiffness and output stability under low-speed, high-torque conditions, and meeting the requirements of heavy-load, high-impact, and high-precision rotation on large vertical lathe workpiece turntables.

[0028] 8. Based on the performance verification results, the average output torque of both the front and rear motor units is 9.60 Nm, and the combined average output torque of the entire machine is 19.21 Nm. The torque ripple rates of the front and rear motor units are 12.68% and 12.93%, respectively, while the combined torque ripple rate of the entire machine is reduced to 3.23%. Therefore, this invention can significantly reduce torque ripple while increasing the average output torque. Compared with traditional single-sided permanent magnet peripheral arc motors and traditional bidirectional modulation motors, it is more suitable for low-speed, high-torque, stable-speed, creep-free, and heavy-load, high-rigidity direct-drive scenarios on large vertical lathe workpiece turntables.

[0029] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0030] Figure 1 This is an exploded view of the motor in an embodiment of this application.

[0031] Figure 2 This is a planar cross-sectional view of the motor in an embodiment of this application.

[0032] Figure 3 This is a perspective view of the motor stator and rotor in the embodiments of this application.

[0033] Figure 4 This is a plan view of the motor stator subunit in the embodiments of this application.

[0034] Figure 5 This is a plan view of the motor rotor in an embodiment of this application.

[0035] Figure 6 This is a schematic diagram illustrating the effect of the phase sequence arrangement of the three-phase coil group in an embodiment of this application.

[0036] Figure 7 These are cross-sectional views of the permanent magnet stator and permanent magnet rotor motors in the embodiments of this application.

[0037] Figure 8 This is a comparison diagram of the motor output torque before and after operation in the embodiments of this application.

[0038] Figure 9 This is a comparison diagram of the output torque of the motor in this embodiment of the application with that of a stator permanent magnet type motor and a rotor permanent magnet type motor.

[0039] Figure 10 This is a comparison diagram of the output torque of the motor and the conventional motor in the embodiments of this application; Explanation of reference numerals in the attached figures: 1. Stator auxiliary teeth; 2. Tangential permanent magnet of the first tooth section; 3. Tangential permanent magnet of the second tooth section; 4. Radial permanent magnet of the yoke section; 5. Main teeth of the stator core; 6. Armature winding; 7. Stator yoke section; 8. Rotor teeth; 9. Radial permanent magnet of the rotor; 10. Rotor shaft; 11. Rotor yoke. Detailed Implementation

[0040] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of the present invention. Furthermore, the accompanying drawings of the present invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention.

[0041] Example 1: This example provides a circumferentially bidirectional multi-unit distributed arc permanent magnet synchronous motor. Combined with... Figure 1 , Figure 2 and Figure 3 As shown, a circumferential bidirectional multi-unit distributed arc permanent magnet synchronous motor includes a segmented stator assembly, a coaxial rotor assembly, and an armature winding 6; in the figure, Ⅰ represents the segmented stator assembly, and Ⅱ represents the coaxial rotor assembly; The segmented stator assembly includes three arc-shaped stator sub-units arranged discontinuously along the circumferential direction. The three arc-shaped stator sub-units are distributed around the coaxial rotor assembly at a spatial interval of 120°, and an arc-shaped air gap is formed between each arc-shaped stator sub-unit and the coaxial rotor assembly. The coaxial rotor assembly includes a front rotor section and a rear rotor section arranged coaxially. The segmented stator assembly has a front stator region corresponding to the front rotor section and a rear stator region corresponding to the rear rotor section. The front stator region and the front rotor section form a front motor unit, and the rear stator region and the rear rotor section form a rear motor unit. The front stator region and the rear stator region are axially integrated stator structures, and the arc-shaped stator sub-units corresponding to the front stator region and the rear stator region have the same structure and size; Combination Figure 4 As shown, each of the arc-shaped stator sub-units includes a stator yoke 7, a plurality of stator core main teeth 5, a stator slot disposed between adjacent stator core main teeth 5, a stator auxiliary tooth 1, an armature winding 6 disposed in the stator slot, a yoke radial permanent magnet 4 embedded in the stator yoke 7, and a tooth tangential permanent magnet disposed between adjacent stator core main teeth 5 and located on both sides of the stator core main teeth 5; Figure 4 The direction of the middle arrow indicates the magnetization direction of the permanent magnet; Combination Figure 5 As shown, the coaxial rotor assembly includes a rotor shaft 10, a rotor yoke 11, rotor teeth 8 alternately distributed along the outer periphery of the rotor yoke 11, and rotor radial permanent magnets 9. Figure 5 The magnetization direction of the permanent magnet is radially outward; The front rotor segment and the rear rotor segment are set apart by half a rotor pole pitch in the circumferential direction. The front stator region and the rear stator region have no relative displacement in the circumferential direction. The armature winding 6 is a centralized cross winding shared by the front motor unit and the rear motor unit. The armature winding 6 is connected in series to form a bidirectional complementary structure that combines circumferential distribution and axial staggering.

[0042] Optionally, each of the arc-shaped stator sub-units occupies a 72° mechanical angle in the circumferential direction, and the three arc-shaped stator sub-units are distributed in a discontinuous fan shape along the circumferential direction. The coaxial rotor assembly is a cylindrical rotor structure that extends axially and passes through the inner side of the three arc-shaped stator sub-units.

[0043] Optional, combined Figure 6 As shown, each of the arc-shaped stator sub-units has 6 stator slots. The armature winding 6 is arranged in a winding arrangement unit with the 6 stator slots of each arc-shaped stator sub-unit, and is arranged in the three-phase coil group phase sequence of ACB, ACB, CBA, CBA, BAC, BAC from one circumferential end of the arc-shaped stator sub-unit to the other circumferential end. Wherein, A, B, and C represent the A phase, B phase, and C phase of the armature winding 6, respectively. The armature winding 6 is not wound on the stator auxiliary tooth 1.

[0044] Optionally, the toothed tangential permanent magnet includes a first toothed tangential permanent magnet 2 and a second toothed tangential permanent magnet 3, wherein the first toothed tangential permanent magnet 2 and the second toothed tangential permanent magnet 3 are alternately arranged in the circumferential direction, and the tangential magnetization directions of the first toothed tangential permanent magnet 2 and the second toothed tangential permanent magnet 3 are opposite, so as to form a face-to-face magnetic focusing structure between adjacent stator core main teeth 5.

[0045] Optionally, the radial permanent magnet 4 of the yoke corresponding to the front rotor segment is magnetized radially outward, and the radial permanent magnet 4 of the yoke corresponding to the rear rotor segment is magnetized radially inward, so that the radial magnetization directions of the radial permanent magnet 4 of the yoke corresponding to the front motor unit and the rear motor unit are opposite.

[0046] Optionally, both the front rotor section and the rear rotor section include 50 rotor teeth 8 and 50 rotor radial permanent magnets 9. The outer periphery of the rotor yoke 11 is provided with unevenly spaced slots arranged in the circumferential direction. The rotor teeth 8 are formed between adjacent unevenly spaced slots. The rotor radial permanent magnets 9 are disposed in the slotted area between adjacent rotor teeth 8. The rotor teeth 8 and the rotor radial permanent magnets 9 are arranged alternately in the circumferential direction to form an alternating pole structure of permanent magnets-rotor teeth 8, and 50 pairs of pole structures are formed in the circumferential direction.

[0047] Optionally, the radial permanent magnets 9 of the front rotor section and the rear rotor section have opposite polarities, and the circumferential misalignment angle between the front rotor section and the rear rotor section is a mechanical angle of 180 / 50°, so that the front motor unit and the rear motor unit are 180° apart in electrical angle.

[0048] Optionally, the radial permanent magnet 4 of the yoke, the tangential permanent magnet of the tooth and the radial permanent magnet 9 of the rotor together constitute a three-source composite excitation structure, and the three-source composite excitation structure forms a composite modulation magnetic circuit at the arc-shaped air gap.

[0049] Optionally, the stator core main teeth 5, the stator auxiliary teeth 1, the stator yoke 7, the rotor teeth 8, and the rotor magnetic yoke 11 are all formed by stacking silicon steel sheets, and the radial permanent magnet 4 of the yoke, the tangential permanent magnet of the teeth, and the radial permanent magnet 9 of the rotor are all neodymium iron boron permanent magnets.

[0050] Optionally, the silicon steel sheet is a DW315_35 silicon steel sheet, the neodymium iron boron permanent magnet is an N42SH grade neodymium iron boron permanent magnet, and the rotor shaft 10 is located at the center of the rotor yoke 11 and is used to connect the workpiece turntable of a large vertical lathe.

[0051] Furthermore, in combination Figure 2 and Figure 3 As shown, the segmented stator assembly is a non-continuous segmented arc structure. The three arc-shaped stator sub-units are independent of each other in the circumferential direction and form an intermittent arc-shaped surrounding structure around the coaxial rotor assembly. The coaxial rotor assembly extends axially and passes through the inner space enclosed by the three arc-shaped stator sub-units, so that the three arc-shaped stator sub-units form discontinuous arc-shaped air gaps with the outer circumferential surface of the coaxial rotor assembly. With this structure, the motor can avoid the difficulties in processing, transportation, and assembly caused by using a large-diameter integrated annular stator. At the same time, the arc-shaped stator sub-units can be modularly arranged and expanded according to the diameter and load requirements of the workpiece turntable of a large vertical lathe.

[0052] Furthermore, the front motor unit and the rear motor unit are arranged side-by-side along the axial direction to form a bidirectional circumferential structure. The front motor unit is composed of N-pole permanent magnets, and the rear motor unit is composed of S-pole permanent magnets. Both the front and rear motor units are alternating-pole bilateral magnetic field modulation arc permanent magnet motors, and they have the same stator and rotor structures. The front stator region and the rear stator region do not shift relative to each other in the circumferential direction, so the armature winding 6 can be used by both the front and rear motor units. The front rotor segment and the rear rotor segment are offset by half a rotor pole pitch in the circumferential direction, so that the cogging torque component generated by the front motor unit and the cogging torque component generated by the rear motor unit are complementary in phase.

[0053] Combination Figure 4 As shown, in the arc-shaped stator sub-unit, the stator auxiliary tooth 1 is used to cooperate with the stator core main tooth 5 to define the spatial position of the stator slot and assist in forming a local magnetic circuit boundary; the first tooth tangential permanent magnet 2 and the second tooth tangential permanent magnet 3 are respectively disposed between adjacent stator core main teeth 5, and the tangential magnetization directions of the first tooth tangential permanent magnet 2 and the second tooth tangential permanent magnet 3 are opposite; the yoke radial permanent magnet 4 is embedded in the region near the stator yoke 7, the armature winding 6 is disposed in the stator slot, and the stator yoke 7 connects multiple stator core main teeth 5 and forms a stator-side magnetic conduction path. After the first tooth tangential permanent magnet 2 and the second tooth tangential permanent magnet 3 are arranged oppositely, a face-to-face magnetic focusing effect is formed between adjacent stator core main teeth 5, so that the magnetic flux originally dispersed near the stator teeth and stator yoke 7 is concentrated in the arc-shaped air gap region, thereby increasing the effective magnetic flux density amplitude at the arc-shaped air gap.

[0054] Regarding the stator-side magnet arrangement, the yoke radial permanent magnet 4 provides the main magnetic flux component distributed along the radial direction, while the toothed tangential permanent magnet provides the focusing magnetic flux component distributed tangentially along the circumferential direction. For the front stator region corresponding to the front rotor section, the yoke radial permanent magnet 4 is magnetized radially outward; for the rear stator region corresponding to the rear rotor section, the yoke radial permanent magnet 4 is magnetized radially inward. Through these opposite radial magnetization directions, the front motor unit and the rear motor unit form corresponding bidirectional magnetic field modulation structures in the axial direction. Combined with the focusing effect of the toothed tangential permanent magnet, the stator-side magnetic flux and the rotor-side magnetic flux can be superimposed and modulated at the arc-shaped air gap.

[0055] Combination Figure 5 As shown, in the coaxial rotor assembly, rotor teeth 8 are spaced apart along the outer circumferential direction of the rotor yoke 11, and rotor radial permanent magnets 9 are disposed in the slotted area between adjacent rotor teeth 8. The rotor shaft 10 is disposed at the center of the rotor yoke 11, which is a cylindrical magnetically conductive structure. The rotor teeth 8 and the rotor radial permanent magnets 9 are arranged alternately along the circumferential direction to form an alternating pole structure of "permanent magnet-rotor teeth". Since both the front rotor section and the rear rotor section include 50 rotor teeth 8 and 50 rotor radial permanent magnets 9, 50 pairs of pole structures can be formed in the circumferential direction. While ensuring the high pole number magnetic field modulation capability of the rotor, the alternating pole arrangement reduces the amount of permanent magnets used.

[0056] Furthermore, the uneven slotting on the outer periphery of the rotor yoke 11 forms a rotor salient pole structure, which, together with the rotor radial permanent magnet 9, participates in air gap magnetic permeability modulation. The magnetization direction of the rotor radial permanent magnet 9 is radial, and the rotor radial permanent magnet 9 in the front rotor section and the rotor radial permanent magnet 9 in the rear rotor section have opposite polarities. When the front rotor section and the rear rotor section are misaligned by a mechanical angle of 180 / 50° along the circumferential direction, they differ by 180° in electrical angle, causing the cogging torque waveforms of the two rotor sections on the same output shaft to be in opposite phase. Thus, when the coaxial rotor assembly outputs the combined torque, the cogging torque pulsations generated by the two rotor sections can cancel each other out, thereby reducing torque pulsations during low-speed operation of the entire machine.

[0057] Furthermore, the armature winding 6 adopts a concentrated cross-winding structure and is arranged according to the three-phase coil group phase sequence ACB, ACB, CBA, CBA, BAC, BAC. This arrangement allows different phase windings within the same arc-shaped stator sub-unit to form a cross distribution in circumferential space, and enables the induced electromotive force distortion among the three arc-shaped stator sub-units to have a complementary relationship. Since the stator core of the arc motor is not a completely closed circular ring structure, edge effects are prone to occur at the stator ends. The concentrated cross-winding can electromagnetically compensate for the induced electromotive force distortion caused by edge effects, thereby suppressing parasitic torque caused by current harmonics.

[0058] Furthermore, the radial permanent magnet 4 of the yoke, the tangential permanent magnet of the tooth section, and the radial permanent magnet 9 of the rotor together constitute a three-source composite excitation structure. The radial permanent magnet 4 of the yoke provides radial excitation to the stator yoke 7, the tangential permanent magnet of the tooth section provides tangential focusing excitation to the stator teeth, and the radial permanent magnet 9 of the rotor provides radial excitation to the rotor. The three-source composite excitation structure forms a composite modulation magnetic circuit at the arc-shaped air gap, enabling the stator-side magnetic field source and the rotor-side magnetic field source to jointly participate in bilateral magnetic field modulation. Compared with the single-sided permanent magnet excitation structure, this structure can improve the amplitude of the effective working harmonics at the arc-shaped air gap and improve the magnetic energy utilization rate of the permanent magnet.

[0059] During operation, when three-phase alternating current is applied to the armature winding 6, a rotating magnetic field component distributed circumferentially is formed in the three arc-shaped stator sub-units. The radial permanent magnet 4 of the yoke, the tangential permanent magnet of the tooth section, and the radial permanent magnet 9 of the rotor respectively form the stator yoke 7, stator tooth section, and rotor-side magnetic field source, which work together in the arc-shaped air gap region. The rotor teeth 8 and rotor yoke 11 modulate the air gap magnetic permeability, generating electromagnetic torque between the armature magnetic field and the permanent magnet magnetic field, which is then output to the workpiece turntable of the large vertical lathe through the rotor shaft 10. Because the coaxial rotor assembly adopts a high-pole alternating pole structure, the motor can output a large electromagnetic torque at low speeds, adapting to the large diameter, heavy load, and strong impact conditions of the workpiece turntable of the large vertical lathe.

[0060] Furthermore, the bidirectional complementary structure combining circumferential distribution and axial staggering in this embodiment includes two complementary directions: firstly, circumferential complementarity, where the three arc-shaped stator sub-units are spatially spaced at 120° intervals in the circumferential direction, and are combined with concentrated cross windings to suppress edge effects at the segmented stator boundaries; secondly, axial complementarity, where the front rotor segment and the rear rotor segment are arranged side-by-side in the axial direction and staggered by half a rotor pole pitch in the circumferential direction, so that the cogging torque and edge torque generated by the front and rear motor units are complementary in phase. Through the combined effect of circumferential and axial complementarity, torque ripple can be reduced at the structural level without relying on complex subsequent control compensation.

[0061] Combination Figure 7 As shown, both the rotor permanent magnet type peripheral shaft motor (a) and the stator permanent magnet type peripheral shaft motor (b) can be used as comparative structures in this embodiment. The rotor permanent magnet type peripheral shaft motor mainly relies on the rotor-side permanent magnets for excitation, while the stator side mainly has armature windings; the stator permanent magnet type peripheral shaft motor mainly relies on the stator-side permanent magnets for excitation, while the rotor side mainly uses magnetic permeability modulation through magnetically guided salient poles. Unlike the above-mentioned single-sided permanent magnet excitation structure, this embodiment has permanent magnets on both the stator and rotor sides, and the stator side simultaneously has radial permanent magnets in the yoke and tangential permanent magnets in the teeth, so that the motor forms a double-sided composite modulation structure in which the stator yoke radial excitation, the stator tooth tangential focusing magnetic excitation, and the rotor radial excitation all participate.

[0062] Combination Figure 8As shown, under rated operating conditions, the average output torque of both the front and rear motor units is 9.60 Nm. The torque ripple rate of the front motor unit is 12.68%, and that of the rear motor unit is 12.93%. Because the front and rear rotor segments are offset by half a rotor pole pitch in the circumferential direction, the torque ripple waveforms of the two motor segments are 180° out of phase in space. When the front and rear motor units output coaxially through the same rotor shaft 10, their average torques are superimposed, resulting in an overall average output torque of 19.21 Nm. Simultaneously, their torque ripple components cancel each other out, reducing the overall torque ripple rate to 3.23%.

[0063] Combination Figure 9 As shown, under the same rated operating conditions, the average output torque of the stator permanent magnet type peripheral arc permanent magnet motor is approximately 11.60 Nm, and the average output torque of the rotor permanent magnet type peripheral arc permanent magnet motor is approximately 7.60 Nm. The peripheral bidirectional multi-unit distributed arc permanent magnet synchronous motor described in this embodiment simultaneously employs stator-side permanent magnet excitation and rotor-side permanent magnet excitation, and forms a composite modulation magnetic circuit at the arc-shaped air gap through a three-source composite excitation structure. This allows the effective operating harmonics on both the stator and rotor sides to participate in torque output, thus achieving an average output torque of 19.21 Nm. Therefore, this embodiment can improve the average output torque within a limited installation space and is suitable for low-speed, high-torque direct-drive scenarios.

[0064] Combination Figure 10 As shown, although traditional bidirectional modulation motors can output a near-average torque, their internal harmonics are not sufficiently suppressed through axial segmentation and circumferential phase misalignment, resulting in severe torque fluctuations and a torque ripple rate of up to 12.68%. This embodiment utilizes circumferential misalignment of half the rotor pole pitch in the front and rear rotor sections, along with the circumferential distribution of three arc-shaped stator sub-units and the coordinated use of concentrated cross windings. This allows odd-order disturbance harmonics to cancel each other out during coaxial output, thereby reducing the overall torque ripple rate to 3.23% while maintaining a high average torque.

[0065] As can be seen from the above structure and working process, this embodiment reduces the difficulty of integrated manufacturing and assembly of large-diameter stators by using segmented stator assemblies, achieves coaxial output of the front and rear motor units by using coaxial rotor assemblies, improves the effective magnetic flux density and average output torque at the arc-shaped air gap by using a three-source composite excitation structure, suppresses the edge effect of the arc-shaped stator sub-units by using concentrated cross windings, and suppresses cogging torque pulsation by using circumferential misalignment of half the rotor pole pitch of the front and rear rotor sections. Therefore, this embodiment can balance high torque density, low torque pulsation, reduced permanent magnet usage, modular expansion, and heavy-load high-rigidity output, making it suitable for low-speed, high-torque direct drive of large vertical lathe workpiece turntables.

[0066] Example 2: This example provides a performance verification embodiment for a circumferentially bidirectional multi-unit distributed arc permanent magnet synchronous motor. This embodiment is based on the structure described in Example 1, and combines... Figures 7 to 10 The torque output capability, torque ripple suppression effect, and performance differences with different topologies of the aforementioned bidirectional multi-unit distributed arc permanent magnet synchronous motor are explained.

[0067] Combination Figure 7 As shown, Figure 7 (a) shows the front and rear cross-sectional structures of a rotor permanent magnet type peripheral shaft motor. Figure 7 (b) shows the front and rear cross-sectional structures of the stator permanent magnet type peripheral axis motor. The rotor permanent magnet type peripheral axis motor primarily provides excitation through rotor-side permanent magnets, while the stator side mainly houses the armature winding; the stator permanent magnet type peripheral axis motor primarily provides excitation through stator-side permanent magnets, while the rotor side mainly serves as a magnetically conductive salient pole structure to participate in magnetic field modulation. Both of these structures can serve as the basic topologies for performance comparison with the peripheral axis bidirectional multi-unit distributed arc permanent magnet synchronous motor described in this embodiment.

[0068] and Figure 7 Compared to the two single-sided permanent magnet topologies shown, the circumferential bidirectional multi-unit distributed arc permanent magnet synchronous motor described in this embodiment simultaneously provides permanent magnets on both the stator and rotor sides. Specifically, the stator side includes a yoke radial permanent magnet 4 embedded in the stator yoke 7 and a tooth tangential permanent magnet disposed between adjacent stator core main teeth 5. The rotor side includes a rotor radial permanent magnet 9 disposed between adjacent rotor teeth 8. Thus, the yoke radial permanent magnet 4, the tooth tangential permanent magnet, and the rotor radial permanent magnet 9 together constitute a three-source composite excitation structure, so that the stator-side radial excitation, the stator tooth tangential focusing excitation, and the rotor-side radial excitation all act on the arc-shaped air gap, thereby increasing the effective magnetic field strength in the arc-shaped air gap region.

[0069] Combination Figure 8 As shown, under rated operating conditions, the front motor unit and the rear motor unit respectively generate output torque. Figure 8 The horizontal axis represents the rotor position in electrical degrees; the vertical axis represents the output torque in Nm. The diagram includes three torque curves: the front motor, the rear motor, and the combined circumferential bidirectional complementary motor. Figure 8 It can be seen that the average output torque of the front motor unit is 9.60 Nm, and the average output torque of the rear motor unit is also 9.60 Nm. Since the front motor unit and the rear motor unit output coaxially through the same rotor shaft 10, their average output torques can be superimposed at the output end of the whole machine, so that the combined average output torque of the whole machine reaches 19.21 Nm.

[0070] Further integration Figure 8As shown, the torque ripple rate of the front motor unit is 12.68%, and the torque ripple rate of the rear motor unit is 12.93%. Because the front rotor segment and the rear rotor segment in Embodiment 1 are misaligned by a 180 / 50° mechanical angle in the circumferential direction, meaning they differ by half a rotor pole pitch, the torque ripple waveforms of the front motor unit and the rear motor unit are spatially phase-wise 180° out of phase. When they are combined and output through the same rotor shaft 10, the torque ripple components of the two motor segments cancel each other out, reducing the overall torque ripple rate of the combined unit to 3.23%. Therefore, Figure 8 The results show that the half-pole misalignment structure of the front rotor section and the rear rotor section can significantly reduce the torque pulsation of the whole machine while maintaining the average torque superposition.

[0071] Combination Figure 9 As shown, Figure 9 The graph shows electromagnetic torque comparison curves for different topologies under rated operating conditions. The horizontal axis represents rotor position in electrical degrees; the vertical axis represents output torque in Nm. The graph includes output torque curves for a stator permanent magnet type peripheral arc permanent magnet motor, a rotor permanent magnet type peripheral arc permanent magnet motor, and the peripheral bidirectional multi-unit distributed arc permanent magnet synchronous motor described in this embodiment. Figure 9 It can be seen that the average output torque of the stator permanent magnet type peripheral arc permanent magnet motor is about 11.60 Nm, the average output torque of the rotor permanent magnet type peripheral arc permanent magnet motor is about 7.60 Nm, and the average output torque of the peripheral bidirectional multi-unit distributed arc permanent magnet synchronous motor described in this embodiment is 19.21 Nm.

[0072] Depend on Figure 9 The comparison results show that when only the stator-side permanent magnet excitation structure is used, the motor mainly relies on the magnetic permeability modulation between the stator-side permanent magnet and the rotor salient pole to generate torque; when only the rotor-side permanent magnet excitation structure is used, the motor mainly relies on the interaction between the rotor-side permanent magnet and the stator armature winding 6 to generate torque. The average output torque of the above two single-side excitation structures is lower than that of the structure described in this embodiment. This embodiment simultaneously uses a stator-side yoke radial permanent magnet 4, a stator-side tooth tangential permanent magnet, and a rotor-side rotor radial permanent magnet 9, which enables the magnetic field sources on the stator side and the rotor side to participate in modulation together at the arc-shaped air gap, thereby improving the effective operating harmonic amplitude and increasing the overall average output torque.

[0073] Furthermore, the tangential permanent magnets in the tooth section form a face-to-face magnetic focusing structure between adjacent stator core main teeth 5, transforming the stator teeth from a traditional magnetic guiding structure into a magnetic field generating structure that participates in excitation and magnetic focusing. After the tangential permanent magnets in the tooth section cooperate with the radial permanent magnets in the yoke section 4, they can concentrate the stator-side magnetic flux into the arc-shaped air gap region; after the rotor radial permanent magnets 9 are alternately arranged with the rotor teeth 8, they can form an alternating pole structure on the rotor side and participate in air gap magnetic permeability modulation. Through the above-mentioned three-source composite excitation structure, this embodiment can improve the utilization rate of permanent magnets and the average output torque while reducing the amount of permanent magnets used.

[0074] Combination Figure 10 As shown, Figure 10 The figure shows a comparison curve of the electromagnetic torque of a conventional bidirectional modulation motor and the circumferential bidirectional multi-unit distributed arc permanent magnet synchronous motor described in this embodiment under rated operating conditions. The horizontal axis in the figure represents the rotor position in electrical degrees; the vertical axis represents the output torque in Nm. The structure of the conventional bidirectional modulation motor corresponds to the structure of the single-side sub-motor in this embodiment, and the axial length of the conventional bidirectional modulation motor is equal to the axial length of the motor described in this embodiment.

[0075] Depend on Figure 10 It is known that although traditional bidirectional modulation motors can output a near-average torque, their output torque fluctuates significantly, with a torque ripple rate reaching 12.68%. In contrast, the circumferential bidirectional multi-unit distributed arc permanent magnet synchronous motor described in this embodiment reduces the overall torque ripple rate to 3.23% while maintaining a high average output torque. This result indicates that simply increasing the axial length or adopting a single-sided sub-motor structure cannot effectively suppress torque ripple. However, this embodiment achieves a more stable output torque by offsetting the half-pole pitch of the front and rear rotor sections and using coaxial output of the front and rear motor units, thus canceling out the torque ripples generated by the front and rear motor units in phase.

[0076] Furthermore, Figure 10 The comparison also illustrates that the low torque ripple effect in this embodiment is not solely due to an increase in average torque, but rather originates from a bidirectional complementary structure combining circumferential distribution and axial staggering. The three arc-shaped stator sub-units are arranged discontinuously in the circumferential direction with a 120° spatial interval, and work in conjunction with concentrated cross windings to suppress the edge-end effect caused by core breakage in the arc motor. The front and rear rotor sections are arranged side-by-side in the axial direction and staggered circumferentially by half a rotor pole pitch to suppress the cogging effect caused by double-sided slotting and salient pole topology. The combined effect of these two complementary methods enables the entire machine to achieve a relatively flat torque waveform at low speeds.

[0077] Depend on Figures 8 to 10The performance verification results show that, compared with single-sided stator permanent magnet type peripheral arc permanent magnet motors, single-sided rotor permanent magnet type peripheral arc permanent magnet motors, and traditional bidirectional modulation motors, the peripheral arc permanent magnet synchronous motor described in this embodiment can improve the average output torque while reducing torque ripple. Specifically, the average output torque of the front motor unit and the rear motor unit is 9.60 Nm, and the combined average output torque of the whole machine is 19.21 Nm; the torque ripple rates of the front motor unit and the rear motor unit are 12.68% and 12.93%, respectively, and the combined torque ripple rate of the whole machine is reduced to 3.23%. Therefore, this embodiment can verify the effects of the three-source composite excitation structure, centralized cross winding, and front and rear rotor half-pole misalignment structure described in Embodiment 1 in improving torque density, reducing torque ripple, and improving low-speed stability.

[0078] In summary, this embodiment, without adding new structural components or control processes, is based on Figures 7 to 10 The performance comparison results shown illustrate the technical effects of the motor in this application: the average output torque is improved by bilateral permanent magnet excitation on both the stator and rotor sides; the magnetic field utilization rate is improved by the magnetic focusing effect of the toothed tangential permanent magnets; the torque pulsation phase is made complementary by the semi-pole pitch misalignment of the front and rear rotors; and the edge effect is suppressed by three arc-shaped stator sub-units and concentrated cross windings. Thus, the circumferential bidirectional multi-unit distributed arc permanent magnet synchronous motor meets the application requirements of large vertical lathe workpiece turntables for low-speed, high-torque, stable speed without crawling, and heavy-load, high-rigidity drive.

[0079] The content disclosed above is only a preferred and feasible embodiment of the present invention, and is not intended to limit the scope of protection of the present invention. Therefore, all equivalent technical changes made based on the content of the present invention specification and drawings are included within the scope of protection of the present invention. Furthermore, the elements therein can be updated as technology develops.

Claims

1. A circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor, characterized in that, It includes a segmented stator assembly, a coaxial rotor assembly, and an armature winding (6); The segmented stator assembly includes three arc-shaped stator sub-units arranged discontinuously along the circumferential direction. The three arc-shaped stator sub-units are distributed around the coaxial rotor assembly at a spatial interval of 120°, and an arc-shaped air gap is formed between each arc-shaped stator sub-unit and the coaxial rotor assembly. The coaxial rotor assembly includes a front rotor section and a rear rotor section arranged coaxially. The segmented stator assembly has a front stator region corresponding to the front rotor section and a rear stator region corresponding to the rear rotor section. The front stator region and the front rotor section form a front motor unit, and the rear stator region and the rear rotor section form a rear motor unit. The front stator region and the rear stator region are axially integrated stator structures, and the arc-shaped stator sub-units corresponding to the front stator region and the rear stator region have the same structure and size; Each of the arc-shaped stator subunits includes a stator yoke (7), a plurality of stator core main teeth (5), a stator slot disposed between adjacent stator core main teeth (5), a stator auxiliary tooth (1), an armature winding (6) disposed in the stator slot, a yoke radial permanent magnet (4) embedded in the stator yoke (7), and tooth tangential permanent magnets disposed between adjacent stator core main teeth (5) and located on both sides of the stator core main teeth (5); The coaxial rotor assembly includes a rotor shaft (10), a rotor yoke (11), rotor teeth (8) alternately distributed along the outer periphery of the rotor yoke (11), and rotor radial permanent magnets (9); The front rotor segment and the rear rotor segment are set apart by half a rotor pole pitch in the circumferential direction. The front stator region and the rear stator region have no relative displacement in the circumferential direction. The armature winding (6) is a centralized cross winding shared by the front motor unit and the rear motor unit. The armature winding (6) is connected in series to form a bidirectional complementary structure that combines circumferential distribution and axial interlacing.

2. The circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor according to claim 1, characterized in that, Each of the arc-shaped stator sub-units occupies a mechanical angle of 72° in the circumferential direction. The three arc-shaped stator sub-units are distributed in a discontinuous fan shape along the circumferential direction. The coaxial rotor assembly is a cylindrical rotor structure that extends axially and passes through the inner side of the three arc-shaped stator sub-units.

3. The circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor according to claim 1, characterized in that, The toothed tangential permanent magnet includes a first toothed tangential permanent magnet (2) and a second toothed tangential permanent magnet (3). The first toothed tangential permanent magnet (2) and the second toothed tangential permanent magnet (3) are alternately arranged in the circumferential direction, and the tangential magnetization directions of the first toothed tangential permanent magnet (2) and the second toothed tangential permanent magnet (3) are opposite, so as to form a face-to-face magnetic focusing structure between adjacent stator core main teeth (5).

4. The circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor according to claim 1, characterized in that, The radial permanent magnet (4) of the yoke corresponding to the front rotor segment is magnetized radially outward, and the radial permanent magnet (4) of the yoke corresponding to the rear rotor segment is magnetized radially inward, so that the radial magnetization directions of the radial permanent magnet (4) of the yoke corresponding to the front motor unit and the rear motor unit are opposite.

5. A circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor according to claim 1, characterized in that, Both the front rotor section and the rear rotor section include 50 rotor teeth (8) and 50 rotor radial permanent magnets (9). The outer periphery of the rotor yoke (11) is provided with non-uniform slots arranged in the circumferential direction. The rotor teeth (8) are formed between adjacent non-uniform slots. The rotor radial permanent magnets (9) are arranged in the slot area between adjacent rotor teeth (8). The rotor teeth (8) and the rotor radial permanent magnets (9) are arranged alternately in the circumferential direction to form a permanent magnet-rotor tooth (8) alternating pole structure, and 50 pairs of pole structures are formed in the circumferential direction.

6. A circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor according to claim 5, characterized in that, The radial permanent magnets (9) of the front rotor section and the rear rotor section have opposite polarities, and the circumferential misalignment angle between the front rotor section and the rear rotor section is 180 / 50° mechanical angle, so that the front motor unit and the rear motor unit are 180° apart in electrical angle.

7. A circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor according to claim 1, characterized in that, The radial permanent magnet of the yoke (4), the tangential permanent magnet of the tooth and the radial permanent magnet of the rotor (9) together constitute a three-source composite excitation structure, and the three-source composite excitation structure forms a composite modulation magnetic circuit at the arc-shaped air gap.

8. A circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor according to claim 1, characterized in that, The stator core main teeth (5), the stator auxiliary teeth (1), the stator yoke (7), the rotor teeth (8), and the rotor magnetic yoke (11) are all formed by stacking silicon steel sheets. The radial permanent magnet (4) of the yoke, the tangential permanent magnet of the teeth, and the radial permanent magnet (9) of the rotor are all neodymium iron boron permanent magnets.

9. A circumferential-axis bidirectional multi-unit distributed arc permanent magnet synchronous motor according to claim 8, characterized in that, The silicon steel sheet is a DW315_35 silicon steel sheet, the neodymium iron boron permanent magnet is an N42SH grade neodymium iron boron permanent magnet, and the rotor shaft (10) is located at the center of the rotor yoke (11) and is used to connect the workpiece turntable of the large vertical lathe.

Images