High-torque-density magnetic planetary speed reduction axial permanent magnet driving motor

Abstract

The invention discloses a high-torque-density magnetic planetary speed reduction axial permanent magnet driving motor, which comprises an axial permanent magnet motor and a radial magnetic planetary speed reducer, and is characterized in that the axial permanent magnet motor comprises a motor stator, a motor left rotor, a motor right rotor, a permanent magnet and an armature winding, and the motor left rotor and the motor right rotor are distributed on two sides of the stator; the radial magnetic planetary reducer comprises a magnetic planetary reducer stator, a magnetic planetary reducer planet wheel, a magnetic planetary reducer sun wheel and a permanent magnet; the axial permanent magnet motor adopts a single-stator double-rotor axial structure, the magnetic planetary reducer adopts a radial structure and is embedded in a hollow position inside the axial permanent magnet motor, and the axial permanent magnet motor and the magnetic planetary reducer adopt surface-mounted permanent magnet structures; through the integrated structure that the magnetic planetary reducer stator and the axial permanent magnet motor stator are rigidly connected, the magnetic planetary reducer and the axial permanent magnet motor are directly coupled, a mechanical reducer structure of a traditional driving system is omitted, and the overall weight of the driving system is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors and drive motors, and in particular to a high torque density magnetic planetary reduction axial permanent magnet drive motor. Background Art

[0002] Permanent magnet motors, with their advantages of high efficiency, high torque density, high power factor, compact size, and low temperature rise, are widely used in industrial drive systems such as electric ships, electric vehicles, and robots. However, currently, industrial drive systems both domestically and internationally are primarily powered by radial permanent magnet motors coupled with mechanical reducers. This results in problems such as low torque density, large size, complex installation, and low transmission efficiency. In contrast, direct-drive permanent magnet motors operate by directly driving the system, effectively improving the torque density and transmission efficiency of the drive system. However, existing direct-drive radial permanent magnet motors are limited by their structure and operating principles, making it difficult to further increase their torque density. To address these issues, axial permanent magnet motors, thanks to their flattening characteristics, further utilize the space at the winding ends, thereby significantly improving torque density compared to radial permanent magnet motors.

[0003] Compared with traditional axial permanent magnet motors, magnetic field modulation axial permanent magnet motors benefit from their advantages of high torque density and low torque pulsation, making them easy to meet the application requirements of low speed and high torque under the space constraints of the drive system. This type of motor achieves self-deceleration by introducing magnetic poles to modulate the air gap magnetic field. However, due to the performance limits of permanent magnet materials, its torque density at large reduction ratios still cannot meet application requirements, and its maximum reduction ratio is still far lower than that of mechanical reducers. A single magnetic field modulation axial permanent magnet motor still cannot replace the combination of traditional drive motors and mechanical reducers. In addition, the insufficient space utilization of the hollow part of the motor means that the lightweight and high torque density design of the magnetic field modulation axial permanent magnet motor needs to be further optimized. Therefore, in order to meet the performance requirements of the electric drive system, improving the torque density of the drive motor is a key issue that needs to be solved urgently. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a high torque density magnetic planetary reduction axial permanent magnet drive motor to achieve low-speed and high-torque output of the electric drive system without a mechanical reducer, thereby improving the torque density of the electric drive system.

[0005] Technical solution: A high-torque density magnetic planetary reduction axial permanent magnet drive motor, including an axial permanent magnet motor and a radial magnetic planetary reducer. The axial permanent magnet motor includes a motor stator, a left motor rotor, and a right motor rotor. The left motor rotor and the right motor rotor are distributed on both sides of the motor stator. The motor stator is provided with an armature winding; the left motor rotor is provided with a left rotor permanent magnet; the right motor rotor is provided with a right rotor permanent magnet;

[0006] The radial magnetic planetary reducer includes a magnetic planetary reducer stator, a magnetic planetary reducer planetary gear and a magnetic planetary reducer sun gear. The magnetic planetary reducer stator is provided with a magnetic planetary reducer stator permanent magnet; the magnetic planetary reducer planetary gear is provided with a magnetic planetary reducer planetary gear permanent magnet, and is connected to the magnetic planetary reducer planetary gear carrier through a magnetic planetary reducer planetary gear bearing; the magnetic planetary reducer sun gear is provided with a magnetic planetary reducer sun gear permanent magnet, and is connected to the output end through a magnetic planetary reducer sun gear bearing;

[0007] The motor stator is directly mechanically coupled to the magnetic planetary reducer stator to form an integrated stator structure.

[0008] Furthermore, axial permanent magnet motor stator teeth are provided in the motor stator, and the armature winding is wound on the axial permanent magnet motor stator teeth.

[0009] Furthermore, the stator teeth of the axial permanent magnet motor act as modulation teeth, and realize magnetic field modulation in conjunction with the number of pole pairs of the motor stator and rotor, and are of unequal radius structure near the air gap between the stator and rotor of the axial permanent magnet motor.

[0010] Furthermore, the armature winding is distributed along the circumference of the motor stator using a drum-shaped winding and uses a rectangular cross-section wire.

[0011] Furthermore, the number of pole pairs of the permanent magnets of the left rotor of the motor is equal to that of the permanent magnets of the right rotor of the motor, forming a single-stator-dual-rotor structure with the motor stator; the number of pole pairs of the permanent magnets of the left rotor of the motor, the permanent magnets of the right rotor of the motor and the stator armature winding is different, and the design adopts the magnetic field modulation principle.

[0012] Furthermore, the permanent magnets of the left rotor of the motor and the permanent magnets of the right rotor of the motor are both of unequal radius structures on the side close to the air gap between the stator and rotor of the axial permanent magnet motor.

[0013] Compared with the prior art, the present invention has the following significant effects:

[0014] 1. This invention directly and rigidly connects the axial permanent magnet motor and the radial magnetic planetary reducer through an integrated stator structure, reducing mechanical losses and reducing the volume and weight of the drive system. The two-stage self-deceleration of the axial permanent magnet motor and the radial magnetic planetary reducer enables low-speed, high-torque output of the electric drive system without a mechanical reducer, effectively improving the torque density of the electric drive system.

[0015] 2. The axial permanent magnet motor of the present invention is designed using the principle of magnetic field modulation, directly coupling the magnetic poles to the stator. Because the number of permanent magnet pole pairs is much greater than that of the armature winding pole pairs, this achieves self-deceleration while improving torque output. At the same time, it further reduces the axial length of the motor, which is conducive to further improving the motor's torque density. The single-stator-dual-rotor design greatly reduces the impact of axial unbalanced magnetic pull on motor performance.

[0016] 3. The axial permanent magnet motor of the present invention adopts a modular yokeless stator core, drum winding, split teeth and other structures, which makes the stator easy to modularize, convenient for transportation and installation, while reducing end leakage magnetic flux and improving motor efficiency;

[0017] 4. The stator teeth, the permanent magnets of the left rotor and the right rotor of the axial permanent magnet motor of the present invention all adopt an unequal radius design method on the air gap side, thereby achieving spatial symmetry of the motor magnetic field, thereby increasing the motor output torque while reducing torque fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 It is a structural exploded diagram of the present invention;

[0020] Figure 3 This is a schematic structural diagram of the axial permanent magnet motor of the present invention;

[0021] Figure 4 This is a schematic structural diagram of the radial magnetic planetary reducer of the present invention;

[0022] Figure 5 It is a schematic diagram of the drum winding structure of the present invention;

[0023] Figure 6 This is an axial expansion diagram of the axial permanent magnet motor of the present invention;

[0024] Figure 7 This is the magnetic circuit diagram of the magnetic field modulation principle of the axial permanent magnet motor of the present invention;

[0025] Figure 8 It is a schematic diagram of the ring winding structure of the present invention;

[0026] Figure 9 This is a schematic structural diagram of the three-planet radial magnetic planetary reducer of the present invention;

[0027] In the figure: 1. Axial permanent magnet motor; 2. Radial magnetic planetary reducer; 3. Motor stator; 31. Armature winding; 32. Stator teeth of axial permanent magnet motor; 33. Stator of magnetic planetary reducer; 34. Stator permanent magnets of magnetic planetary reducer; 4. Left rotor of motor; 41. Permanent magnets of left rotor of motor; 5. Right rotor of motor; 51. Permanent magnets of right rotor of motor; 6. Planet gears of magnetic planetary reducer; 61. Planet gear permanent magnets of magnetic planetary reducer; 62. Planet gear bearings of magnetic planetary reducer; 7. Sun gear of magnetic planetary reducer; 71. Permanent magnets of sun gear of magnetic planetary reducer; 72. Sun gear bearings of magnetic planetary reducer; 8. Planet carrier of magnetic planetary reducer; 9. Air gap between stator and rotor of axial permanent magnet motor; 10. Permanent magnets of unequal radius on rotor of axial permanent magnet motor; 11. Stator teeth of unequal radius on stator of axial permanent magnet motor; 12. Harmonics of rotor pole pair number; 13. Harmonics of armature winding pole pair number. DETAILED DESCRIPTION

[0028] The present invention will be described in further detail below with reference to the accompanying drawings and specific implementations.

[0029] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "thickness", "middle", "length", "inside", "outside", "all around" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0030] like Figure 1 、 Figure 2 As shown, the present invention provides an embodiment, a high torque density magnetic planetary reduction axial permanent magnet drive motor, including an axial permanent magnet motor 1 and a radial magnetic planetary reducer 2.

[0031] like Figure 3 As shown, the axial permanent magnet motor 1 includes a motor stator 3, a motor left rotor 4 and a motor right rotor 5. The motor left rotor 4 and the motor right rotor 5 are distributed on both sides of the stator 3; the stator 3 is provided with an armature winding 31; the motor left rotor 4 is provided with a motor left rotor permanent magnet 41; the motor right rotor 5 is provided with a motor right rotor permanent magnet 51.

[0032] The motor stator 3 adopts a modular yokeless stator structure, that is, axial permanent magnet motor stator teeth 32 are provided in the motor stator 3 , and the armature winding 31 is wound on the axial permanent magnet motor stator teeth 32 .

[0033] The motor stator 3 is directly mechanically coupled to the magnetic planetary reducer stator 33 to form an integrated stator structure.

[0034] In the axial permanent magnet motor 1, the permanent magnets 41 of the left rotor and 51 of the right rotor are both surface-mounted, and the magnetization direction is axial, which is beneficial to reducing torque pulsation. At the same time, in order to improve the torque output capacity, the magnetic field modulation principle is applied. The number of pole pairs of the permanent magnets 41 of the left rotor and the number of pole pairs of the permanent magnets 51 of the right rotor are equal, and the number of pole pairs of the armature winding 31 and the number of pole pairs of the permanent magnets 41 and 51 of the left rotor are unequal. The stator magnetic field is spatially harmonically decomposed by the axial permanent magnet motor stator teeth 32 to achieve air gap magnetic field modulation, thereby achieving the effect of speed reduction and torque increase. The principle is as follows:

[0035] If the number of stator teeth is P s , the number of pole pairs of the armature winding is P a , then the number of pole pairs P of the permanent magnets of the left and right rotors of the motor is r The number of spatial harmonic pole pairs in the magnetic flux density distribution of the generated low-speed rotating magnetic field satisfies:

[0036] P r =|P s ±P a |

[0037] Then the reduction ratio G of the magnetic field modulation type axial permanent magnet motor is m for:

[0038]

[0039] Therefore, the expression of the average output torque T of the magnetic field modulated axial permanent magnet motor can be written as:

[0040] T=3G m B g N s I rms k w1 D i (D o -D i )

[0041] Where, B g is the single-side air gap magnetic flux amplitude; N s is the number of winding turns; I rms is the effective value of the winding phase current; k w1 is the fundamental wave winding coefficient; D i is the inner diameter of the stator core; D o is the outer diameter of the stator core.

[0042] Compared with the ordinary axial permanent magnet synchronous motor, the torque formula of the magnetic field modulation axial permanent magnet motor has G m The magnification factor shows that the magnetic field modulation axial permanent magnet motor has a higher torque density than the ordinary axial permanent magnet synchronous motor.

[0043] The motor stator 3 of the axial permanent magnet motor 1 adopts a modular design, with each axial permanent magnet motor stator tooth 32 and armature winding 31 as each subunit, which is convenient for installation and transportation while reducing electromagnetic loss and improving motor efficiency.

[0044] like Figure 5 As shown, the armature winding 31 is distributed along the circumference of the motor stator 3 using drum-shaped windings, and uses rectangular cross-section wires to reduce the possibility of short circuits.

[0045] like Figure 4 As shown, the radial magnetic planetary reducer 2 includes a magnetic planetary reducer stator 33, a magnetic planetary reducer planetary gear 6 and a magnetic planetary reducer sun gear 7. The magnetic planetary reducer stator 33 is provided with a magnetic planetary reducer stator permanent magnet 34; the four magnetic planetary reducer planetary gears 6 are respectively provided with a magnetic planetary reducer planetary gear permanent magnet 61; the magnetic planetary reducer sun gear 7 is provided with a magnetic planetary reducer sun gear permanent magnet 71; the magnetic planetary reducer planetary gear 6 is fixed to the magnetic planetary reducer planet carrier 8 through the magnetic planetary reducer planetary gear bearing 62; the magnetic planetary reducer sun gear 7 is connected to the output end through the magnetic planetary reducer sun gear bearing 72.

[0046] The radial magnetic planetary reducer 2 achieves a torque gain effect from the magnetic planetary reducer stator 33 to the magnetic planetary reducer sun gear 7 through the combined action of the magnetic planetary reducer stator permanent magnet 34, the magnetic planetary reducer planet gear permanent magnet 61 and the magnetic planetary reducer sun gear permanent magnet 71.

[0047] If the number of magnetic pole pairs of the planetary gear of the radial magnetic planetary reducer is P p ; The magnetic field rotation angular velocity of the sun gear of the magnetic planetary reducer is ω sun , the number of magnetic pole pairs is P sun ; The angular velocity of the magnetic field of the magnetic planetary reducer stator is ω c , the number of magnetic pole pairs is P c ; The angular velocity of the planet carrier of the magnetic planetary reducer is ω b The transmission ratio of the radial magnetic planetary reducer is G r r for:

[0048]

[0049] Since the radial magnetic planetary reducer stator 33 is fixed, ω c =0, then:

[0050]

[0051] The transmission ratio of the radial magnetic planetary reducer can be rewritten as:

[0052]

[0053] In this embodiment, the present invention directly couples the motor stator 3 with the magnetic planetary reducer stator 33 to form an integrated stator structure, thereby achieving two-stage self-deceleration and even reaching the reduction ratio that can be output by current mechanical reducers.

[0054] In summary, the torque output gain ratio λ of the magnetic planetary reduction axial permanent magnet drive motor is:

[0055] λ=G m ·G r b

[0056] like Figure 6 As shown, the axial permanent magnet motor stator teeth 32 and the motor left rotor permanent magnets 41 and the motor right rotor permanent magnets 51 are all designed with unequal radius structures near the air gap 9 between the stator and rotor of the axial permanent magnet motor, namely, the axial permanent magnet motor unequal radius stator teeth 11 and the axial permanent magnet motor rotor unequal radius permanent magnets 10, so as to improve the sine degree of the air gap magnetic flux density of the axial permanent magnet motor and improve the output performance of the motor.

[0057] like Figure 7 Figure 2 shows a schematic diagram of the magnetic circuit for an axial permanent magnet motor (PMM) using the magnetic field modulation principle. Based on this magnetic field modulation principle, the alternating action of the stator teeth and slots allows effective harmonic flux to pass through the air gap, forming a closed loop between the different axial PMM stator teeth 32 and the left and right rotors 4 and 5, enabling the flow of rotor pole-pair harmonics 12. Furthermore, a portion of the fundamental magnetic flux can form a closed loop between adjacent axial PMM stator teeth 32, effectively linking the armature windings and forming armature winding pole-pair harmonics 13. This achieves a synergistic effect between the effective harmonic magnetic field and the rotor fundamental magnetic field, thereby enhancing the motor's performance improvement due to the effective harmonics to meet its high torque density requirements.

[0058] like Figure 8 As shown, the axial permanent magnet motor 1 adopts a ring-shaped armature winding 31 structure, so that when the motor diameter is large and the number of armature winding pole pairs is small, the amount of copper wire used can be reduced, thereby reducing copper loss while reducing costs and improving motor operating efficiency.

[0059] like Figure 9 As shown, the planetary gear 6 of the magnetic planetary magnetic reducer can also adopt a three-planetary gear structure design, which is suitable for the situation where the high torque density magnetic planetary reducer axial permanent magnet drive motor has a small size and the hollow part inside the axial permanent magnet motor has insufficient space, while reducing the amount of permanent magnets used and reducing costs.

[0060] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0061] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A high torque density magnetic planetary reduction axial permanent magnet drive motor, comprising an axial permanent magnet motor (1) and a radial magnetic planetary reduction gear (2), characterized in that: The axial permanent magnet motor (1) comprises a motor stator (3), a motor left rotor (4), and a motor right rotor (5), wherein the motor left rotor (4) and the motor right rotor (5) are distributed on both sides of the motor stator (3); an armature winding (31) is provided on the motor stator (3); a motor left rotor permanent magnet (41) is provided on the motor left rotor (4); and a motor right rotor permanent magnet (51) is provided on the motor right rotor (5); The radial magnetic planetary reducer (2) comprises a magnetic planetary reducer stator (33), a magnetic planetary reducer planetary gear (6) and a magnetic planetary reducer sun gear (7), wherein the magnetic planetary reducer stator (33) is provided with a magnetic planetary reducer stator permanent magnet (34); the magnetic planetary reducer planetary gear (6) is provided with a magnetic planetary reducer planetary gear permanent magnet (61), and is connected to the magnetic planetary reducer planetary carrier (8) via a magnetic planetary reducer planetary gear bearing (62); the magnetic planetary reducer sun gear (7) is provided with a magnetic planetary reducer sun gear permanent magnet (71), and is connected to the output end via a magnetic planetary reducer sun gear bearing (72); The motor stator (3) is directly mechanically coupled to the magnetic planetary reducer stator (33) to form an integrated stator structure.

2. The high torque density magnetic planetary reduction axial permanent magnet drive motor according to claim 1, characterized in that: Axial permanent magnet motor stator teeth (32) are provided in the motor stator (3), and the armature winding (31) is wound around the axial permanent magnet motor stator teeth (32).

3. The high torque density magnetic planetary reduction axial permanent magnet drive motor according to claim 2, characterized in that: The axial permanent magnet motor stator teeth (32) act as modulation teeth, cooperate with the motor stator and rotor pole pairs to achieve magnetic field modulation, and are of unequal radius structure on the side close to the air gap (9) between the stator and rotor of the axial permanent magnet motor.

4. The high torque density magnetic planetary reduction axial permanent magnet drive motor according to claim 2, characterized in that: The armature winding (31) is distributed along the circumference of the motor stator (3) using a drum-shaped winding and uses a rectangular cross-section conductor.

5. The high torque density magnetic planetary reduction axial permanent magnet drive motor according to claim 1, characterized in that: The motor left rotor permanent magnet (41) and the motor right rotor permanent magnet (51) have the same number of pole pairs, and form a single stator-double rotor structure with the motor stator (3); the motor left rotor permanent magnet (41), the motor right rotor permanent magnet (51) and the stator armature winding (31) have different numbers of pole pairs, and are designed using the magnetic field modulation principle.

6. The high torque density magnetic planetary reduction axial permanent magnet drive motor according to any one of claims 1 to 5, characterized in that: The motor left rotor permanent magnet (41) and the motor right rotor permanent magnet (51) are both unequal radius structures on the side close to the air gap (9) between the stator and rotor of the axial permanent magnet motor.

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