Field-enhanced axial flux switching hub motor

Abstract

The magnetic field enhanced axial flux switching hub motor belongs to the technical field of permanent magnet motors. It is designed to solve the problems of poor motor fault tolerance, low motor torque density, and poor heat resistance in existing hub motors. It includes: the first rotor and the second rotor are of the same disc structure, and the intermediate stator is embedded between the first rotor and the second rotor; the intermediate stator includes: armature teeth are respectively arranged at both ends of the H-type stator core, and fault-tolerant teeth are arranged in the middle of the H-type stator core. The main permanent magnet is sandwiched between two adjacent armature teeth, the magnetizing permanent magnet is embedded inside the fault-tolerant teeth, and the armature winding is wound on the stator yoke between the armature teeth and the fault-tolerant teeth. The two adjacent main permanent magnets are magnetized by a tangential magnetization method with opposite magnetization directions, and the two adjacent magnetizing permanent magnets are magnetized by a tangential magnetization method with opposite magnetization directions. The present invention is used for hub motors.

Description

Technical Field

[0001] The invention relates to a magnetic field enhancement type axial magnetic flux switching hub motor, belonging to the technical field of permanent magnet motors. Background Art

[0002] Electric vehicles are gradually becoming the mainstream trend of future new energy vehicle development due to their zero emission characteristics. Most of the current electric vehicles use centralized drive mode, and their power transmission generally needs to be transmitted to the drive wheel through mechanical devices such as gearboxes, differentials, drive shafts and universal joints. The transmission chain is long and the efficiency is low. As a power system with distributed drive characteristics, the wheel hub motor is directly installed in the drive wheel, which has outstanding advantages such as short transmission chain, efficient transmission and compact structure, and has attracted extensive attention from domestic and foreign scholars and mainstream car manufacturers.

[0003] As a core component in electric vehicles, the working performance of the hub motor directly affects the performance of the electric vehicle. However, due to the space limitations in the wheel hub and the vehicle's requirements for the torque and weight of the hub motor, the hub motor requires a compact structure and high torque density index. The axial flux motor has the advantages of compact axial size and large output torque. It is suitable for distributed hub-driven electric vehicles and other direct drive occasions with strict space constraints. However, the permanent magnets of traditional axial flux motors are installed on the rotor. When the motor heats up, the rotor is difficult to cool, and it is easy to have faults such as permanent magnet demagnetization.

[0004] In response to the above problems, an axial flux switching motor is proposed. The motor places both permanent magnets and armature windings on the stator, and there are neither windings nor permanent magnets on the rotor, making the rotor structure simple and strong. While ensuring mechanical strength, the heat dissipation requirements of the rotor are reduced. For example, patent No. ZL201720494366.8 discloses an axial magnetic field flux switching permanent magnet motor. However, for hub motors, the motors work in an environment with water, oil, dust, etc. for a long time, the reliability of electrical components is not as good as mechanical components, and the possibility of failure during the operation of electric vehicles is relatively high. The axial flux switching permanent magnet is not suitable for hub motors.

[0005] Patent No. ZL201711181547.6 discloses a rotor permanent magnet type hybrid excitation axial flux switching permanent magnet motor, which proposes an H-type axial flux switching motor. The stator core of this type of motor is assembled with an "H"-shaped magnetic conductive unit and a permanent magnet. The armature winding is placed on the armature teeth, and a fault-tolerant tooth is provided between the two armature teeth, which enhances the fault tolerance of the motor. However, the permanent magnets of this type of motor only exist between the armature teeth of the "H"-shaped magnetic conductive unit, and the volume of permanent magnets that can be accommodated is limited. In order to obtain a larger air gap magnetic density, the axial length of the motor stator can only be increased, which leads to an increase in the length of the motor, an increase in the leakage magnetic flux of the permanent magnet, and it is difficult to improve the power density of the motor.

[0006] Therefore, it is necessary to design a new type of axial flux switching motor to meet the requirements of automotive hub motors. Summary of the invention

[0007] The purpose of the present invention is to solve the problems of poor motor fault tolerance, low motor torque density and poor heat resistance in existing hub motors, and to provide a magnetic field enhanced axial flux switching hub motor.

[0008] The magnetic field enhancement type axial flux switching hub motor of the present invention comprises a first rotor, an intermediate stator and a second rotor;

[0009] The first rotor and the second rotor are of the same disc structure, and the middle stator is embedded between the first rotor and the second rotor;

[0010] The intermediate stator comprises an H-shaped stator core, a main permanent magnet, a magnetizing permanent magnet, an armature winding, an armature tooth and a fault-tolerant tooth;

[0011] Armature teeth are respectively arranged at both ends of the H-type stator core, and fault-tolerant teeth are arranged in the middle of the H-type stator core. A main permanent magnet is sandwiched between two adjacent armature teeth, and the magnetization permanent magnet is embedded in the fault-tolerant teeth. The armature winding is wound on the stator yoke between the armature teeth and the fault-tolerant teeth.

[0012] Preferably, the first rotor includes 10 rotor teeth, adopts a salient pole structure, and is evenly spaced on the inner side of the rotor disk. The intermediate stator includes 6 H-type stator cores. The 6 main permanent magnets are respectively clamped between two adjacent armature teeth, and the 6 magnetizing permanent magnets are respectively embedded in the fault-tolerant teeth. The 12 armature windings are wound on the stator yoke between the armature teeth and the fault-tolerant teeth.

[0013] Preferably, the six main permanent magnets are respectively a first main permanent magnet, a second main permanent magnet, a third main permanent magnet, a fourth main permanent magnet, a fifth main permanent magnet and a sixth main permanent magnet;

[0014] The six magnetization permanent magnets are respectively a first magnetization permanent magnet, a second magnetization permanent magnet, a third magnetization permanent magnet, a fourth magnetization permanent magnet, a fifth magnetization permanent magnet and a sixth magnetization permanent magnet;

[0015] The first main permanent magnet and the first magnetization permanent magnet have the same magnetization direction, the second main permanent magnet and the second magnetization permanent magnet have the same magnetization direction, the third main permanent magnet and the third magnetization permanent magnet have the same magnetization direction, the fourth main permanent magnet and the fourth magnetization permanent magnet have the same magnetization direction, the fifth main permanent magnet and the fifth magnetization permanent magnet have the same magnetization direction, and the sixth main permanent magnet and the sixth magnetization permanent magnet have the same magnetization direction.

[0016] Preferably, two adjacent main permanent magnets are magnetized by a tangential magnetization method with opposite magnetization directions, and two adjacent magnetization-enhancing permanent magnets are magnetized by a tangential magnetization method with opposite magnetization directions.

[0017] Preferably, the armature winding adopts a three-phase distributed centralized unidirectional annular winding.

[0018] Preferably, the fault-tolerant teeth are a double fault-tolerant tooth structure.

[0019] Preferably, both the first rotor and the second rotor adopt a straight pole structure.

[0020] Preferably, when the torque pulsation is large, both the first rotor and the second rotor adopt a skewed pole structure.

[0021] Preferably, both the main permanent magnet and the magnetizing permanent magnet are made of neodymium iron boron material.

[0022] Advantages of the present invention:

[0023] 1. The rotor of the axial flux switching hub motor proposed by the present invention has neither permanent magnets nor windings, which can increase the heat resistance of the motor while ensuring mechanical strength.

[0024] 2. The stator core is assembled from H-type magnetic conductive units and permanent magnets, and is equipped with fault-tolerant teeth, which can effectively improve the reliability and fault-tolerant capability of the motor.

[0025] 3. Adding a magnetizing permanent magnet between two adjacent main permanent magnets can increase the air gap magnetic flux density of the motor, improve the motor power and torque density, and also improve the magnetic field waveform of the main permanent magnet, reduce eddy current loss, and improve motor efficiency.

[0026] 4. The annular winding structure is adopted, and the armature winding is separated from the permanent magnet, which reduces the influence of the winding temperature rise on the permanent magnet in the traditional flux switching motor, avoids the high-temperature demagnetization of the permanent magnet caused by the heating of the winding, and effectively improves the overall heat dissipation capacity of the motor.

[0027] 5. The annular winding is in the same direction. The incoming wire ends are not only located on the same side of the stator yoke, but also have the same incoming wire direction. It has a larger winding coefficient, which effectively improves the power and torque density of the motor.

[0028] The present invention proposes a magnetic field enhanced axial flux switching hub motor with higher torque density and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the magnetic field enhancement type axial flux switching hub motor of the present invention;

[0030] Figure 2 This is an axial view of the magnetic field enhancement type axial flux switching hub motor of the present invention;

[0031] Figure 3 It is a schematic diagram of the permanent magnet distribution and magnetization method of the magnetic field enhanced axial flux switching hub motor of the present invention;

[0032] Figure 4 13 represents the upper right air gap, 14 represents the upper left air gap, a1 and a2 represent the magnetic force line trend diagram of the main permanent magnet, and b1 and b2 represent the magnetic force line trend diagram of the magnetization permanent magnet;

[0033] Figure 5 is a schematic diagram of the armature winding of the present invention;

[0034] Figure 6 It is the slot potential star diagram of the present invention. DETAILED DESCRIPTION

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

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0037] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0038] Embodiment 1:

[0039] Combine the following Figure 1-Figure 6 This embodiment is described. The magnetic field enhancement type axial flux switching hub motor described in this embodiment includes a first rotor 1, an intermediate stator 2 and a second rotor 3;

[0040] The first rotor 1 and the second rotor 3 are of the same disc structure, and the middle stator 2 is embedded between the first rotor 1 and the second rotor 3;

[0041] The intermediate stator 2 includes an H-shaped stator core 4, a main permanent magnet 5, a magnetizing permanent magnet 6, an armature winding 7, an armature tooth 9 and a fault-tolerant tooth 10;

[0042] Armature teeth 9 are respectively provided at both ends of the H-type stator core 4, and a fault-tolerant tooth 10 is provided in the middle of the H-type stator core 4. A main permanent magnet 5 is clamped between two adjacent armature teeth 9, and a magnetizing permanent magnet 6 is embedded in the inside of the fault-tolerant tooth 10. The armature winding 7 is wound on the stator yoke 12 between the armature teeth 9 and the fault-tolerant teeth 10.

[0043] Furthermore, the first rotor 1 includes 10 rotor teeth 11, which adopt a salient pole structure and are evenly spaced on the inner side of the rotor disk. The intermediate stator 2 includes 6 H-type stator cores 4. The 6 main permanent magnets 5 are respectively clamped between two adjacent armature teeth 9. The 6 magnetizing permanent magnets 6 are respectively embedded in the fault-tolerant teeth 10. The 12 armature windings 7 are wound on the stator yoke 12 between the armature teeth 9 and the fault-tolerant teeth 10.

[0044] Furthermore, the six main permanent magnets 5 are respectively a first main permanent magnet, a second main permanent magnet, a third main permanent magnet, a fourth main permanent magnet, a fifth main permanent magnet and a sixth main permanent magnet;

[0045] The six magnetization permanent magnets 6 are respectively a first magnetization permanent magnet, a second magnetization permanent magnet, a third magnetization permanent magnet, a fourth magnetization permanent magnet, a fifth magnetization permanent magnet and a sixth magnetization permanent magnet;

[0046] The first main permanent magnet and the first magnetization permanent magnet have the same magnetization direction, the second main permanent magnet and the second magnetization permanent magnet have the same magnetization direction, the third main permanent magnet and the third magnetization permanent magnet have the same magnetization direction, the fourth main permanent magnet and the fourth magnetization permanent magnet have the same magnetization direction, the fifth main permanent magnet and the fifth magnetization permanent magnet have the same magnetization direction, and the sixth main permanent magnet and the sixth magnetization permanent magnet have the same magnetization direction.

[0047] Furthermore, two adjacent main permanent magnets 5 are magnetized in a tangential magnetization manner with opposite magnetization directions, and two adjacent magnetization-enhancing permanent magnets 6 are magnetized in a tangential magnetization manner with opposite magnetization directions.

[0048] Furthermore, the armature winding 7 adopts a three-phase distributed centralized unidirectional annular winding.

[0049] Furthermore, the fault-tolerant tooth 10 is a double fault-tolerant tooth structure.

[0050] Furthermore, both the first rotor 1 and the second rotor 3 adopt a straight pole structure.

[0051] Furthermore, when the torque pulsation is large, both the first rotor 1 and the second rotor 3 adopt a skewed pole structure.

[0052] Furthermore, both the main permanent magnet 5 and the magnetizing permanent magnet 6 are made of neodymium iron boron material.

[0053] In this embodiment, the cores of the first rotor 1 and the second rotor 3 are made of a new type of low-loss super silicon steel material, which can reduce the eddy current loss of the motor, reduce the temperature rise of the motor, and improve the efficiency of the motor.

[0054] In the present invention, Figure 1As shown, it includes a first rotor 1, an intermediate stator 2 and a second rotor 3. The first rotor 1 and the second rotor 3 both adopt a disc-type salient pole structure, and the salient pole structure is evenly distributed on the rotor disk. The intermediate stator 2 is embedded between the first rotor 1 and the second rotor 3, and includes a plurality of H-type stator cores 4, a main permanent magnet 5, a magnetizing permanent magnet 6 and an armature winding 7. Armature teeth 9 and fault-tolerant teeth 10 are respectively provided at both ends and in the middle of the H-type stator core 4. The main permanent magnet 5 is clamped between the armature teeth 9 at one end of the two H-type stator cores 4, and the magnetizing permanent magnet 6 is embedded in the fault-tolerant teeth 10. The adjacent two main permanent magnets 5 adopt a tangential magnetization method with opposite magnetization directions, and the adjacent two magnetizing permanent magnets 6 adopt a tangential magnetization method with opposite magnetization directions. The armature winding 7 is wound on the stator yoke 12 between the armature teeth 9 and the fault-tolerant teeth 10, and the armature winding 7 adopts a three-phase distributed centralized unidirectional annular winding.

[0055] In the first rotor 1 and the second rotor 3, the rotor teeth 11 are both 10, adopting a salient pole structure and evenly distributed on the rotor disk. The stator core 8 of the intermediate stator 2 is composed of 6 H-type stator cores 4, 6 main permanent magnets 5 are clamped between the armature teeth 9 at one end of each two H-type stator cores 4, 6 magnetizing permanent magnets 6 are embedded in the fault-tolerant teeth 10, and 12 annular armature windings 7 are wound on the stator yoke 12 between the armature teeth 9 and the fault-tolerant teeth 10.

[0056] like Figure 2 and Figure 3 As shown, there are 6 main permanent magnets 5 and 6 magnetizing permanent magnets 6 in total, two adjacent main permanent magnets 5 adopt a tangential magnetization method with opposite magnetization directions, and two adjacent magnetizing permanent magnets 6 also adopt a tangential magnetization method with opposite magnetization directions, and the first main permanent magnet and the first magnetizing permanent magnet have the same magnetization direction, the second main permanent magnet and the second magnetizing permanent magnet have the same magnetization direction, the third main permanent magnet and the third magnetizing permanent magnet have the same magnetization direction, the fourth main permanent magnet and the fourth magnetizing permanent magnet have the same magnetization direction, the fifth main permanent magnet and the fifth magnetizing permanent magnet have the same magnetization direction, and the sixth main permanent magnet and the sixth magnetizing permanent magnet have the same magnetization direction.

[0057] like Figure 4As shown, the solid line a1 in the figure is the magnetic force line generated by the main permanent magnet 5, starting from the main permanent magnet 5, passing through the stator yoke 12-armature tooth 9-upper right air gap 13-first rotor 1-upper left air gap 14-fault-tolerant tooth 10-stator yoke 12, and then returning to the main permanent magnet 5. The dotted line b1 is the magnetic force line generated by the magnetization permanent magnet 6, starting from the magnetization permanent magnet 6, passing through the stator yoke 12-armature tooth 9-upper right air gap 13-first rotor 1-upper left air gap 14-fault-tolerant tooth 10, stator yoke 12, and then returning to the magnetization permanent magnet 6. The present invention uses the main permanent magnet 5 and the magnetization permanent magnet 6 in combination, so that the direction of the magnetic field generated by the magnetization permanent magnet 6 is the same as the direction of the magnetic field generated by the main permanent magnet 5 at the air gap, and the magnetic fields of the two are superimposed, which plays a role in increasing the air gap magnetic field. The analysis method of the solid line a2 and the dotted line b2 is the same as that of the solid line a2 and the dotted line b2.

[0058] like Figure 5 and Figure 6 As shown, 12 annular windings 7 are wound on the stator yoke 12 between the armature teeth 9 and the fault-tolerant teeth 10. The armature windings are separated from the permanent magnets, which reduces the influence of the temperature rise of the windings on the permanent magnets in the traditional flux switching motor, avoids the high-temperature demagnetization of the permanent magnets caused by the heating of the windings, and effectively improves the overall heat dissipation capacity of the motor. The incoming wire end of the winding is located on the same side of the stator yoke and has the same incoming wire direction. There is no vector offset between the potentials of different coils in the same phase of the slot potential star diagram. Therefore, the motor of the invention has a large winding coefficient, which effectively improves the power and torque density of the motor.

[0059] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A magnetic field enhanced axial flux switching hub motor, characterized in that: It comprises a first rotor (1), an intermediate stator (2) and a second rotor (3); The first rotor (1) and the second rotor (3) are of the same disc structure, and the intermediate stator (2) is embedded between the first rotor (1) and the second rotor (3); The intermediate stator (2) comprises an H-type stator core (4), a main permanent magnet (5), a magnetizing permanent magnet (6), an armature winding (7), an armature tooth (9) and a fault-tolerant tooth (10); Armature teeth (9) are respectively arranged at both ends of the H-shaped stator core (4), a fault-tolerant tooth (10) is arranged in the middle of the H-shaped stator core (4), a main permanent magnet (5) is sandwiched between two adjacent armature teeth (9), a magnetizing permanent magnet (6) is embedded in the fault-tolerant tooth (10), and an armature winding (7) is wound on a stator yoke (12) between the armature teeth (9) and the fault-tolerant tooth (10); Two adjacent main permanent magnets (5) are magnetized in a tangential magnetization manner with opposite magnetization directions, and two adjacent magnetization-enhancing permanent magnets (6) are magnetized in a tangential magnetization manner with opposite magnetization directions.

2. The magnetic field enhanced axial flux switching hub motor according to claim 1, characterized in that: The first rotor (1) comprises 10 rotor teeth (11) with a salient pole structure and are evenly spaced and distributed on the inner side of a rotor disk; the intermediate stator (2) comprises 6 H-shaped stator cores (4); 6 main permanent magnets (5) are respectively clamped between two adjacent armature teeth (9); 6 magnetizing permanent magnets (6) are respectively embedded in the interior of the fault-tolerant teeth (10); and 12 armature windings (7) are wound on a stator yoke (12) between the armature teeth (9) and the fault-tolerant teeth (10).

3. The magnetic field enhanced axial flux switching hub motor according to claim 2, characterized in that: The six main permanent magnets (5) are respectively a first main permanent magnet, a second main permanent magnet, a third main permanent magnet, a fourth main permanent magnet, a fifth main permanent magnet and a sixth main permanent magnet; The six magnetization permanent magnets (6) are respectively a first magnetization permanent magnet, a second magnetization permanent magnet, a third magnetization permanent magnet, a fourth magnetization permanent magnet, a fifth magnetization permanent magnet and a sixth magnetization permanent magnet; The first main permanent magnet and the first magnetization permanent magnet have the same magnetization direction, the second main permanent magnet and the second magnetization permanent magnet have the same magnetization direction, the third main permanent magnet and the third magnetization permanent magnet have the same magnetization direction, the fourth main permanent magnet and the fourth magnetization permanent magnet have the same magnetization direction, the fifth main permanent magnet and the fifth magnetization permanent magnet have the same magnetization direction, and the sixth main permanent magnet and the sixth magnetization permanent magnet have the same magnetization direction.

4. The magnetic field enhanced axial flux switching hub motor according to claim 1 or 2, characterized in that: The armature winding (7) adopts a three-phase distributed centralized unidirectional annular winding.

5. The magnetic field enhanced axial flux switching hub motor according to claim 4, characterized in that: The fault-tolerant tooth (10) is a double fault-tolerant tooth structure.

6. The magnetic field enhanced axial flux switching hub motor according to claim 5, characterized in that: The first rotor (1) and the second rotor (3) both adopt a straight pole structure.

7. The magnetic field enhanced axial flux switching hub motor according to claim 6, characterized in that: When the torque pulsation is large, both the first rotor (1) and the second rotor (3) adopt a skewed pole structure.

8. The magnetic field enhanced axial flux switching hub motor according to claim 7, characterized in that: The main permanent magnet (5) and the magnetizing permanent magnet (6) are both made of neodymium iron boron material.

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