High torque density magnetic harmonic reduction axial permanent magnet servo motor

Abstract

This invention discloses a high torque density magnetic harmonic reducer axial permanent magnet servo motor. The axial field-modulated motor includes a stator, a left rotor, a right rotor, permanent magnets, and armature windings. The radial magnetic harmonic reducer includes a stator, an outer rotor, an inner rotor, permanent magnets, and ball bearings. This invention integrates the stator of the magnetic harmonic reducer with the stator of the field-modulated motor, directly connecting them and eliminating the mechanical reducer structure of traditional servo systems, effectively reducing the overall weight of the servo system. The field-modulated motor uses an axial structure to improve the torque density of the servo system. The magnetic harmonic reducer uses a radial structure embedded in the hollow space inside the field-modulated motor to achieve a lightweight, highly integrated servo system design. Both the field-modulated motor and the magnetic harmonic reducer use surface-mounted permanent magnet structures to reduce torque ripple.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet synchronous motors and servo motors, and specifically relates to a high torque density magnetic harmonic deceleration axial permanent magnet servo motor. Background Technology

[0002] Traditional radial permanent magnet motors, due to their similar stator and rotor slot pole numbers, experience increased slot leakage and decreased slot fill factor as the rotor pole number increases, necessitating a larger motor size to meet output requirements. Consequently, motor efficiency and torque density decrease. In contrast, radial field modulation motors, benefiting from high torque density and low torque ripple, easily meet the low-speed, high-torque application requirements of servo systems within space constraints. These motors achieve "self-deceleration" by modulating the air gap magnetic field through pole adjustment; however, limited by the performance limitations of permanent magnet materials, their torque density still cannot meet application requirements at high reduction ratios.

[0003] To further improve torque density, the flattening characteristic of axial field modulated motors at the same torque output can compensate for the reduced torque density caused by wasted end space in traditional radial field modulated motors. However, at the current research level, the maximum reduction ratio of axial field modulated motors is still far lower than that of mechanical reducers. A single axial field modulated motor cannot replace the combination of a traditional servo motor and a mechanical reducer, and the insufficient space utilization in the hollow part of the motor means that the lightweight and high torque density design of axial field modulated motors needs further optimization. Therefore, how to further improve the torque density of servo motors remains an urgent problem to be solved. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by providing a high torque density magnetic harmonic deceleration axial permanent magnet servo motor, which can improve the space utilization of the hollow part of the motor and increase the torque density of the servo motor.

[0005] To solve the above technical problems, the present invention provides the following technical solution: a high torque density magnetic harmonic reduction axial permanent magnet servo motor, comprising: an axial magnetic field modulation type motor and a radial magnetic harmonic reducer;

[0006] The axial magnetic field modulation type motor includes a stator, a right rotor, and a left rotor, with the right rotor and the left rotor distributed on both sides of the stator.

[0007] The stator is provided with an armature winding; the right rotor of the motor is provided with a right rotor permanent magnet; the left rotor of the motor is provided with a left rotor permanent magnet.

[0008] The radial magnetic harmonic reducer includes a magnetic harmonic reducer stator, a magnetic harmonic reducer outer rotor, a magnetic harmonic reducer inner rotor, and ball bearings. The magnetic harmonic reducer stator is provided with a magnetic harmonic reducer stator permanent magnet; the magnetic harmonic reducer outer rotor is provided with a magnetic harmonic reducer outer rotor permanent magnet; the magnetic harmonic reducer outer rotor and the magnetic harmonic reducer inner rotor are connected by ball bearings.

[0009] The magnetic harmonic reducer axial permanent magnet servo motor directly mechanically couples the motor stator with the magnetic harmonic reducer stator to form an integrated stator structure.

[0010] Furthermore, the aforementioned stator adopts a yokeless segmented stator structure, that is, stator teeth are provided inside the stator, and the armature winding is wound on the stator teeth.

[0011] Furthermore, the stator teeth that extend into the air gap are extended circumferentially to improve the utilization rate of the armature winding ends and reduce leakage flux.

[0012] Furthermore, the aforementioned armature winding adopts a drum-shaped winding distributed along the stator circumference and uses rectangular cross-section conductors to reduce the possibility of short circuits.

[0013] Furthermore, the number of pole pairs of the permanent magnets on the right rotor of the motor is equal to that on the left rotor, forming a single stator-dual rotor structure with the stator to reduce axial unbalanced magnetic pull.

[0014] Furthermore, the number of pole pairs of the aforementioned motor right rotor permanent magnet, motor left rotor permanent magnet and stator armature winding are not equal, and the design adopts the principle of magnetic field modulation.

[0015] Furthermore, the aforementioned high torque density magnetic harmonic deceleration axial permanent magnet servo motor has auxiliary slots opened on the stator teeth (32) to form a stator split tooth structure for air gap magnetic field modulation.

[0016] Furthermore, the aforementioned auxiliary slots on the stator teeth form teeth of equal width distributed circumferentially, and the stator teeth have two split small teeth.

[0017] Compared with the prior art, the beneficial technical effects of the present invention using the above technical solution are as follows:

[0018] 1. This invention directly couples an axial magnetic field modulation motor with a radial magnetic harmonic reducer, reducing mechanical losses by eliminating the transmission shaft; through the "two-stage self-reduction" of the servo motor system, low-speed high-torque output is achieved without a mechanical reducer, increasing the torque density of the servo motor and realizing the integrated design of the drive motor and reducer.

[0019] 2. The axial magnetic field modulation motor of this invention adopts a single stator-dual rotor design, which greatly reduces the impact of axial unbalanced magnetic pull on motor performance; the magnetic poles are directly coupled to the stator, and since the number of permanent magnet pole pairs is much greater than the number of armature winding pole pairs, the torque output is improved while achieving self-deceleration, and the axial length of the motor is further reduced, which is conducive to further improving the torque density of the motor.

[0020] 3. The axial magnetic field modulation motor of the present invention adopts a structure such as a yokeless block stator core, drum-shaped winding, and split teeth, which makes the stator easy to modular design, convenient for transportation and installation, and at the same time reduces end leakage flux and improves motor efficiency.

[0021] 4. The output port of the magnetic harmonic reducer axial permanent magnet servo motor of the present invention is the external rotor port of the magnetic harmonic reducer, which can be used as a frameless rotor to directly drive the load, further reducing the mechanical friction loss of the system.

[0022] 5. The stator teeth, rotor, and permanent magnet surfaces of the axial magnetic field modulation motor of this invention adopt an unequal radius design method, which realizes the symmetry of the motor's magnetic field in space, thereby increasing the motor's output torque while reducing torque fluctuation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a high torque density magnetic harmonic deceleration axial permanent magnet servo motor according to the present invention;

[0024] Figure 2 This is an exploded view of the motor structure of the present invention;

[0025] Figure 3 This is a schematic diagram of the axial magnetic field modulation type motor structure of the present invention;

[0026] Figure 4 This is a schematic diagram of the radial magnetic harmonic reducer structure of the motor structure of the present invention;

[0027] Figure 5 This is a schematic diagram of the structure of the magnetic harmonic deceleration axial permanent magnet servo motor of the present invention;

[0028] Figure 6 This is a schematic diagram of the split tooth structure of the present invention;

[0029] Figure 7 This is a schematic diagram of the annular winding structure of the present invention.

[0030] Reference numerals: 1, Axial magnetic field modulation type motor; 2, Radial magnetic harmonic reducer; 3, Stator; 31, Armature winding; 32, Stator teeth; 33, Stator of magnetic harmonic reducer; 34, Permanent magnet of stator of magnetic harmonic reducer; 35, Split stator teeth; 4, Right rotor of the motor; 41, Permanent magnet of right rotor of the motor; 5, Left rotor of the motor; 51, Permanent magnet of left rotor of the motor; 6, Outer rotor of magnetic harmonic reducer; 61, Permanent magnet of outer rotor of magnetic harmonic reducer; 7, Inner rotor of magnetic harmonic reducer; 8, Ball bearing. Detailed implementation manners

[0031] In order to better understand the technical content of the present invention, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows.

[0032] In the present invention, various aspects of the present invention are described with reference to the accompanying drawings, in which many illustrative embodiments are shown. The embodiments of the present invention are not limited to those described in the drawings. It should be understood that the present invention can be implemented by any one of the various concepts and embodiments introduced above, and those described in detail below, because the concepts and embodiments disclosed in the present invention are not limited to any embodiment. In addition, some aspects disclosed in the present invention can be used alone, or in any suitable combination with other aspects disclosed in the present invention.

[0033] Refer Figures 1 to 5 , this embodiment provides a high torque density magnetic harmonic reduction axial permanent magnet servo motor, including an axial magnetic field modulation type motor 1 and a radial magnetic harmonic reducer 2.

[0034] The axial magnetic field modulation type motor 1 includes a stator 3, a right rotor 4 of the motor and a left rotor 5 of the motor. The right rotor 4 and the left rotor 5 of the motor are distributed on both sides of the stator 3; an armature winding 31 is provided on the stator 3; a permanent magnet 41 of the right rotor of the motor is provided on the right rotor 4 of the motor; a permanent magnet 51 of the left rotor of the motor is provided on the left rotor 5 of the motor.

[0035] In the axial magnetic field modulation type motor 1, both the permanent magnet 41 of the right rotor of the motor and the permanent magnet 51 of the left rotor of the motor are surface-mounted, and the magnetization direction is axial magnetization, which is beneficial to reducing torque ripple; at the same time, in order to improve the torque output ability, the magnetic field modulation principle is applied, and the unequal number of pole pairs of the armature winding 31 and the number of pole pairs of the permanent magnet 41 of the right rotor of the motor and the permanent magnet 51 of the left rotor of the motor are used, and the number of pole pairs is modulated by the stator teeth 32 to achieve the effect of speed reduction and torque increase.

[0036] The principle is as follows.

[0037] 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 r of the permanent magnet of the left rotor of the motor and the permanent magnet of the right rotor of the motor should satisfy:

[0038] P r =|P s ±P a |

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

[0040]

[0041] In the formula B g It is the amplitude of the air gap magnetic flux density on one side; N s It is the number of turns in the winding; I rms It is the effective value of the winding phase current; k w1 It is the fundamental winding coefficient; D i It is the inner diameter of the stator core; D o This refers to the outer diameter of the stator core. Compared to ordinary axial permanent magnet synchronous motors, the torque formula of axial field modulation motors has... The amplification factor indicates that the axial magnetic field modulation type motor has a higher torque density than the ordinary axial motor.

[0042] The stator 3 of the axial magnetic field modulation motor adopts a modular design, with each stator core 32 and armature winding 31 as a sub-unit. This facilitates installation and transportation while reducing electromagnetic losses and improving motor efficiency.

[0043] The radial magnetic harmonic reducer 2 includes a magnetic harmonic reducer stator 33, a magnetic harmonic reducer outer rotor 6, a magnetic harmonic reducer inner rotor 7, and a ball bearing 8. The magnetic harmonic reducer stator 33 is provided with a magnetic harmonic reducer stator permanent magnet 34; the magnetic harmonic reducer outer rotor 6 is provided with a magnetic harmonic reducer outer rotor permanent magnet 61.

[0044] Radial magnetic harmonic reducers utilize their different magnetic harmonic reducer external rotor permanent magnets with 61 pole pairs P. o With the 34 pole pairs (P) of the stator permanent magnet of the magnetic harmonic reducer o -1) Achieve the transition from stator to outer rotor The torque gain effect.

[0045] The magnetic harmonic reducer axial permanent magnet servo motor directly couples the motor stator 3 with the magnetic harmonic reducer stator 33 to form an integrated stator structure, thereby achieving two-stage self-reduction, and even reaching the reduction ratio that current mechanical reducers can output.

[0046] In summary, the torque output gain ratio λ of the harmonic drive axial permanent magnet servo motor is:

[0047]

[0048] Example 2

[0049] like Figure 6 As shown, the axial magnetic field modulation type motor adopts a stator split tooth 35 structure, that is, auxiliary slots are opened on the stator teeth 32 to form teeth of equal width distributed in a circular pattern, which plays a role in air gap magnetic field modulation. Each stator tooth has two split small teeth, thereby improving the motor torque output capability while ensuring that its power factor is not too low. The armature winding 31 adopts a drum-shaped winding, which effectively improves the utilization rate of the winding end, reduces copper loss, and improves motor efficiency.

[0050] With the adoption of a split-tooth structure, the modulation ratio of the axial magnetic field modulation motor is:

[0051]

[0052] Then, the expression for the average output torque of the axial magnetic field modulated motor can be written as:

[0053] T=3α(B pm +αB epm )N s I rms k w1 D i (D o -D i )

[0054] In the formula B pm It is the amplitude of the unloaded air gap magnetic flux density fundamental wave; B epm It is the effective harmonic amplitude of the air gap magnetic flux density under no-load conditions.

[0055] Example 3

[0056] like Figure 7 As shown, the axial magnetic field modulation type motor adopts a ring winding 31 structure, which can reduce the amount of copper wire used when the motor diameter is large and the number of armature winding pole pairs is small. This reduces costs, lowers copper consumption, and improves motor operating efficiency.

[0057] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above 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 one or more embodiments or examples.

[0058] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

[0059] While the present invention has been described above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A high torque density magnetic harmonic reduction axial permanent magnet servo motor, comprising: An axial magnetic field modulation type motor (1) and a radial magnetic harmonic reducer (2); characterized in that, The axial magnetic field modulation type motor (1) includes a stator (3), a right rotor (4) and a left rotor (5), with the right rotor (4) and the left rotor (5) distributed on both sides of the stator (3); The stator (3) is provided with an armature winding (31); the right rotor (4) of the motor is provided with a right rotor permanent magnet (41); the left rotor (5) of the motor is provided with a left rotor permanent magnet (51); The radial magnetic harmonic reducer (2) includes a magnetic harmonic reducer stator (33), a magnetic harmonic reducer outer rotor (6), a magnetic harmonic reducer inner rotor (7), and a ball bearing (8). The magnetic harmonic reducer stator (33) is provided with a magnetic harmonic reducer stator permanent magnet (34); the magnetic harmonic reducer outer rotor (6) is provided with a magnetic harmonic reducer outer rotor permanent magnet (61), and the magnetic harmonic reducer outer rotor (6) and the magnetic harmonic reducer inner rotor (7) are connected by the ball bearing (8). The magnetic harmonic reducer axial permanent magnet servo motor directly mechanically couples the motor stator (3) with the magnetic harmonic reducer stator (33) to form an integrated stator structure.

2. The high torque density magnetic harmonic deceleration axial permanent magnet servo motor according to claim 1, characterized in that, The stator (3) adopts a yokeless block stator structure, that is, stator teeth (32) are provided inside the stator (3), and the armature winding (31) is wound on the stator teeth (32).

3. The high torque density magnetic harmonic deceleration axial permanent magnet servo motor according to claim 2, characterized in that, The stator teeth (32) extend into the air gap and are extended circumferentially to improve the utilization rate of the armature winding (31) end and reduce leakage flux.

4. The high torque density magnetic harmonic deceleration axial permanent magnet servo motor according to claim 1, characterized in that, The armature winding (31) adopts a drum-shaped winding distributed along the stator circumference and uses rectangular cross-section conductors to reduce the possibility of short circuit.

5. A high torque density magnetic harmonic deceleration axial permanent magnet servo motor according to claim 1, characterized in that, The number of pole pairs of the permanent magnet (41) on the right rotor of the motor and the permanent magnet (51) on the left rotor of the motor are equal, forming a single stator-double rotor structure with the stator (3) to reduce the axial unbalanced magnetic pull.

6. A high torque density magnetic harmonic deceleration axial permanent magnet servo motor according to claim 1, characterized in that, The number of pole pairs of the permanent magnets (41) and (51) of the right rotor and the stator armature winding (31) of the motor are not equal, and the design adopts the principle of magnetic field modulation.

7. A high torque density magnetic harmonic deceleration axial permanent magnet servo motor according to claim 2, characterized in that, Auxiliary slots are opened on the stator teeth (32) to form a stator split tooth (35) structure, which is used for air gap magnetic field modulation.

8. A high torque density magnetic harmonic deceleration axial permanent magnet servo motor according to claim 7, characterized in that, The stator teeth (32) have auxiliary slots to form teeth of equal width distributed in a circular pattern, and the stator teeth have two split small teeth.

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