An Axial Magnetic Field Modulated Magnetic Gear Using a T-Type Modulation Ring Structure

Abstract

The present invention provides an axially magnetically modulated magnetic gear applying a T-shaped modulation ring structure, belonging to the field of motors. It includes a high-speed and a low-speed permanent magnet rotor and a T-shaped modulation ring. The modulation ring includes a plurality of T-shaped magnetic modulation pole pieces and T-shaped non-magnetic composite pole pieces that are circumferentially arranged alternately and bonded. The high-speed and low-speed permanent magnet rotors each include a rotor core composed of a plurality of rotor yokes, and N-pole and S-pole permanent magnets that are circumferentially embedded between adjacent rotor yokes. The high-speed and low-speed permanent magnet rotors are coaxially sleeved on both sides of the modulation ring and form radial and axial air gaps with it. The present invention can enable the leakage magnetic flux at the inner circumferential end of the rotor yoke of the high-speed and low-speed permanent magnet rotors to enter the T-shaped modulation ring and link with the magnetic flux generated by the corresponding rotor permanent magnet, reducing the leakage magnetic flux at the inner circumferential end of the rotor yokes on both sides. Moreover, the high-speed and low-speed rotors rotate coaxially, which can increase the air-gap magnetic density, thereby improving the gear output torque and torque density. At the same time, the modulation ring is easy to process and has a compact structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and particularly relates to an axially magnetically modulated magnetic gear, and more particularly to an axially magnetically modulated magnetic gear applying a T-shaped modulation ring structure. Background Art

[0002] Traditionally, mechanical gears are used for power transmission in the speed reducers matched with motors. However, mechanical gear transmission has problems such as mechanical wear, high noise, lubrication requirements, and large occupied space, which seriously restrict its application in precision transmission and high-reliability scenarios. Therefore, magnetic gear transmission, as a non-contact transmission technology, has been developed. It transmits torque through the magnetic field coupling between permanent magnets, avoiding the losses caused by mechanical contact, and has significant advantages such as no wear, maintenance-free, and overload protection. In recent years, it has been widely used in industries such as automobiles, wind power generation, and aerospace.

[0003] With the rapid development of the third-generation rare-earth permanent magnet material neodymium-iron-boron (Nd-Fe-B), its maximum energy product (BH)max has exceeded 350 kJ / m 3 , and different from samarium cobalt alloys, NdFeB does not use expensive and scarce metal cobalt, and the content of neodymium in rare earths is 5-10 times richer than that of samarium. Therefore, the raw materials are rich and the cost is low, which lays a key foundation for the efficient design and performance improvement of magnetic gears.

[0004] Limited by the magnetic field modulation mechanism and topological structure, there is still room for improvement in the torque density of existing axial magnetic gears. At present, the technical paths for optimizing torque density mainly focus on the improvement of traditional modulation ring structures. The magnetic gear proposed by M. C. Tsai et al. in the journal paper "3-D Printing-Based Design of Axial Flux Magnetic Gear for High Torque Density" published in IEEE Transactions on Magnetics uses an L-shaped iron pole piece as the modulation ring, and improves the torque density of the magnetic gear by suppressing the leakage magnetic flux at the end of the permanent magnet. However, this structure can only couple the leakage magnetic flux on one side of the high-speed or low-speed rotor. Another way to improve performance is to use a Z-shaped modulation ring in the magnetic gear. For example, the Z-shaped pole shoe magnetic gear proposed by Zhang Bangjing et al. in the literature "Design and Simulation Analysis of Z-shaped Pole Shoe Magnetic Gear with Magnetic Flux Concentration" published in the Journal of Shanghai University of Engineering Science. The Z-shaped pole shoes in the stator increase the coupling area between the rotor and the stator, reducing the magnetic flux leakage on the rotor. However, its high-speed and low-speed rotors do not rotate coaxially, resulting in weak axial magnetic flux coupling, and the Z-shaped modulation ring has high processing complexity and large volume, making it difficult to achieve a compact layout. Summary of the Invention

[0005] In view of the deficiency that the axial magnetic field modulated magnetic gear with an L-shaped / Z-shaped modulation ring in the prior art cannot simultaneously meet multi-objective optimization, that is, it cannot simultaneously take into account multiple characteristics such as double-rotor leakage magnetic flux recovery, high axial magnetic flux coupling efficiency, compact structure, and easy machining, the present invention provides an axial magnetic field modulated magnetic gear applying a T-shaped modulation ring structure, which adopts a new modulation ring topology with double-rotor leakage magnetic flux recovery, high axial magnetic flux coupling efficiency, compact structure, and easy machining, breaking through the technical limitations of the existing axial magnetic gears.

[0006] To achieve the above object, the technical solution provided by the present invention is:

[0007] An axial magnetic field modulated magnetic gear applying a T-shaped modulation ring structure is provided, which includes a high-speed permanent magnet rotor, a low-speed permanent magnet rotor, and a T-shaped modulation ring as a stator;

[0008] The T-shaped modulation ring includes a plurality of T-shaped magnetic modulation pole pieces and a plurality of T-shaped non-magnetic composite material pole pieces that are alternately arranged in the circumferential direction and adhesively bonded in sequence. The T-shaped magnetic modulation pole pieces and the T-shaped non-magnetic composite material pole pieces of the T-shaped modulation ring each include a first rod and a second rod vertically extending from the middle of the first rod. All the first rods of the T-shaped modulation ring extend axially in parallel to form a ring, and all the second rods of the T-shaped modulation ring extend radially outward from the corresponding first rods;

[0009] The high-speed permanent magnet rotor and the low-speed permanent magnet rotor are respectively used to be mounted on a high-speed rotating shaft and a low-speed rotating shaft. The high-speed permanent magnet rotor includes a high-speed rotor iron core composed of a plurality of rotor yokes, and a plurality of N-pole permanent magnets and S-pole permanent magnets embedded between adjacent rotor yokes in the circumferential direction. The low-speed permanent magnet rotor includes a low-speed rotor iron core composed of a plurality of rotor yokes, and a plurality of N-pole permanent magnets and S-pole permanent magnets embedded between adjacent rotor yokes in the circumferential direction. The high-speed permanent magnet rotor and the low-speed permanent magnet rotor are both formed in the layout sequence of N-pole permanent magnet, rotor yoke, S-pole permanent magnet, and rotor yoke;

[0010] The high-speed permanent magnet rotor and the low-speed permanent magnet rotor are respectively coaxially sleeved on the ring formed by the first rods of the T-shaped modulation ring on both sides of the second rods of the T-shaped modulation ring, and have a radial air gap with the first rods and an axial air gap with the second rods, thereby forming obliquely upward and obliquely downward magnetic fluxes that form an angle with both the axial direction and the radial direction. The leakage magnetic flux at the inner circumferential end of the rotor yokes of the high-speed permanent magnet rotor and the low-speed permanent magnet rotor can enter the T-shaped modulation ring, so as to modulate the magnetic flux through the T-shaped modulation ring.

[0011] Further, the number of pole pairs P of the permanent magnets in the high-speed permanent magnet rotor h , the number of pole pairs P of the permanent magnets in the low-speed permanent magnet rotor l , the number of magnetic modulation pole pieces N of the T-shaped modulation ring sSatisfy the relationship: P h +P l =N s .

[0012] Furthermore, the T-type modulation ring includes 25 T-type modulation magnetic pole pieces and 25 T-type non-magnetic composite material pole pieces; the high-speed permanent magnet rotor includes 12 rotor yokes, 6 N-pole permanent magnets and 6 S-pole permanent magnets; the low-speed permanent magnet rotor includes 38 rotor yokes, 19 N-pole permanent magnets and 19 S-pole permanent magnets.

[0013] Furthermore, the N-pole permanent magnets and S-pole permanent magnets in the high-speed permanent magnet rotor are axially magnetized circumferentially, and the magnetization directions are opposite; the N-pole permanent magnets and S-pole permanent magnets in the low-speed permanent magnet rotor are axially magnetized circumferentially, and the magnetization directions are opposite.

[0014] Furthermore, the radial air gap and the axial air gap are 1 - 3 mm.

[0015] Furthermore, both the radial air gap and the axial air gap are 2 mm.

[0016] Furthermore, the T-type modulation magnetic pole pieces of the T-type modulation ring are laminated by silicon steel sheets.

[0017] Furthermore, the T-type non-magnetic composite material pole pieces of the T-type modulation ring are made of epoxy resin.

[0018] The advantages of the present invention are as follows:

[0019] 1. For the axial magnetic field modulation type magnetic gear applying the T-type modulation ring structure proposed by the present invention, by using the T-type modulation ring as the stator and sleeving the high-speed rotor and the low-speed rotor on both sides of the modulation ring, the leakage magnetic fluxes at the inner circumferential ends of the high-speed rotor yoke and the low-speed rotor yoke can enter the interior of the T-type modulation ring and cross-link with the magnetic fluxes generated by the low-speed rotor permanent magnets or the high-speed rotor permanent magnets. Thus, the leakage magnetic fluxes at the inner circumferential ends of the rotor yokes on both sides of the T-type modulation ring are reduced, that is, more magnetic fluxes will pass through the air gap to reach the rotor poles. At the same time, the high-speed rotor and the low-speed rotor rotate coaxially, and the axial magnetic flux coupling efficiency is high. Therefore, the present invention increases the air gap magnetic density, improves the gear output torque and the torque density.

[0020] 2. The T-type modulation ring proposed by the present invention is bonded by a plurality of T-type modulation magnetic pole pieces and T-type non-magnetic composite material pole pieces, which is easy to process. Moreover, the high-speed and low-speed rotors are sleeved on both sides of the modulation ring, and the structure is compact, which helps to realize the compact layout of the magnetic gear and the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Through the following description with reference to the drawings, the above and / or other features and advantages of the present invention will become more easily understood. The drawings are not drawn to scale, and some features are enlarged or reduced to show the details of specific components. In the drawings:

[0022] Figure 1 is the explosion diagram of the axial magnetic field modulated magnetic gear applying the T-shaped modulation ring structure of the present invention;

[0023] Figure 2 is the three-dimensional diagram of the T-shaped modulation ring in the present invention;

[0024] Figure 3 is the three-dimensional diagram of the high-speed permanent magnet rotor in the present invention;

[0025] Figure 4 is the three-dimensional diagram of the low-speed permanent magnet rotor in the present invention;

[0026] Figure 5 is the sectional view of the axial magnetic field modulated magnetic gear of the present invention;

[0027] Figure 6 is the static torque-angle characteristic of the axial magnetic field modulated magnetic gear in the example of the present invention;

[0028] Figure 7 is the dynamic torque characteristic of the axial magnetic field modulated magnetic gear in the example of the present invention;

[0029] Figure 8 is the air-gap magnetic flux density diagram between the high-speed rotor and the stator in the example of the present invention;

[0030] Figure 9 is the harmonic number diagram between the high-speed rotor and the stator in the example of the present invention;

[0031] Figure 10 is the air-gap magnetic flux density diagram between the low-speed rotor and the stator in the example of the present invention;

[0032] Figure 11 is the harmonic number diagram between the low-speed rotor and the stator in the example of the present invention;

[0033] Figure 12 is the magnetic flux of the magnetic gear adopting the T-shaped modulation ring of the present invention;

[0034] Figure 13 is the magnetic flux of the existing magnetic gear adopting the traditional modulation ring.

[0035] In the figure: 1 - high-speed permanent magnet rotor, 11 - high-speed rotor N-pole permanent magnet, 12 - high-speed rotor iron core, 121 - high-speed rotor yoke, 13 - high-speed rotor S-pole permanent magnet; 2 - T-shaped modulation ring, 21 - first rod, 22 - second rod; 3 - low-speed permanent magnet rotor, 31 - low-speed rotor N-pole permanent magnet, 32 - low-speed rotor iron core, 33 - low-speed rotor S-pole permanent magnet; 4 - radial air gap; 5 - axial air gap. Detailed implementation manners

[0036] The present invention will be described in detail below with reference to the accompanying drawings by means of exemplary embodiments of the present invention. It should be noted that the following detailed description of the present invention is for illustrative purposes only and does not limit the present invention.

[0037] The present invention provides an axially magnetically modulated magnetic gear applying a T-shaped modulation ring structure for power transmission in a speed reducer of an electric motor. The novel modulation ring adopting a T-shaped structure can improve the output torque and torque density of the electric motor, and at the same time has the advantages of a compact structure and easy processing.

[0038] First, generally referring to Figure 1 , the axially magnetically modulated magnetic gear applying a T-shaped modulation ring structure provided by the present invention includes a high-speed permanent magnet rotor 1, a low-speed permanent magnet rotor 3, and a T-shaped modulation ring 2 as a stator. The high-speed permanent magnet rotor 1 and the low-speed permanent magnet rotor 3 are respectively used for being mounted on a high-speed rotating shaft and a low-speed rotating shaft to achieve speed reduction of the speed reducer. The connection between the high- and low-speed rotors and the corresponding rotating shafts is a known and mature technology.

[0039] Combined with Figure 2 , the T-shaped modulation ring 2 includes a plurality of T-shaped magnetic poles and a plurality of T-shaped non-magnetic composite material poles that are alternately arranged in the circumferential direction and adhesively bonded in sequence. Only the T-shaped magnetic poles are shown in the figure, and the T-shaped non-magnetic composite material poles are not shown. Their structures are the same as those of the T-shaped magnetic poles. The T-shaped magnetic poles of the T-shaped modulation ring 2 can be laminated by silicon steel sheets. The T-shaped non-magnetic composite material poles are used as fixing members for the T-shaped magnetic poles and can be made of epoxy resin, but other non-magnetic composite materials can also be selected.

[0040] The T-shaped magnetic poles structurally include a first rod 21 and a second rod 22 vertically extending from the middle of the first rod 21. The first rods 21 of all the T-shaped magnetic poles extend axially in parallel to form an annular shape. In particular, the two axial end faces of all the first rods 21 are aligned. The second rods 22 of all the T-shaped magnetic poles extend radially and vertically outward from the middle of the corresponding first rods 21. In particular, all the second rods 22 are located in the same plane. In other words, the corresponding second rods 22 extend from the same axial position in the middle of all the first rods 21. The structure of the T-shaped non-magnetic composite material poles is the same as that of the T-shaped magnetic poles. All the T-shaped magnetic poles and the T-shaped non-magnetic composite material poles are alternately arranged in the circumferential direction and adhesively bonded in sequence to form a modulation ring with a T-shaped cross-section. Adopting this modular modulation ring structure can achieve a lightweight design of the structure, reduce the moment of inertia, and reduce the wind resistance.

[0041] Combined with Figure 3, the high-speed permanent magnet rotor 1 includes a high-speed rotor core 12, a plurality of high-speed rotor N-pole permanent magnets 11 and a plurality of high-speed rotor S-pole permanent magnets 13; the high-speed rotor core 12 is composed of a plurality of high-speed rotor yokes 121, and the high-speed rotor N-pole permanent magnets 11 and the high-speed rotor S-pole permanent magnets 13 are circumferentially embedded between adjacent high-speed rotor yokes 121 to form the layout sequence of high-speed rotor N-pole permanent magnets 11, high-speed rotor yokes 121, high-speed rotor S-pole permanent magnets 13, and high-speed rotor yokes 121, as Figure 5 shown.

[0042] Combined with Figure 4 , the low-speed permanent magnet rotor 3 includes a low-speed rotor core 32, a plurality of low-speed rotor N-pole permanent magnets 31 and a plurality of low-speed rotor S-pole permanent magnets 33; the low-speed rotor core 32 is composed of a plurality of low-speed rotor yokes, and the low-speed rotor N-pole permanent magnets 31 and the low-speed rotor S-pole permanent magnets 33 are circumferentially embedded between adjacent low-speed rotor yokes to form the layout sequence of low-speed rotor N-pole permanent magnets 31, low-speed rotor yokes, low-speed rotor S-pole permanent magnets 33, and low-speed rotor yokes. The permanent magnets in the high-speed and low-speed rotors can both adopt neodymium iron boron permanent magnets.

[0043] Combined with Figure 5 , the high-speed permanent magnet rotor 1 and the low-speed permanent magnet rotor 3 are coaxially sleeved on the ring formed by the first rod 21 of the T-shaped modulation ring 2 on both sides of the second rod 22 of the T-shaped modulation ring 2, and the high-speed permanent magnet rotor 1 and the low-speed permanent magnet rotor 3 respectively form a radial air gap 4 with the first rod 21 and an axial air gap 5 with the second rod 22, thereby forming obliquely upward and obliquely downward magnetic fluxes that are at an angle to both the axial and radial directions. The T-shaped modulation ring 2 is used to modulate the magnetic flux. Specifically, the parts of the first rod of the T-shaped modulation ring of the axial magnetic field modulation type magnetic gear on both sides of the second rod respectively surround the inner peripheral ends of the high-speed rotor yokes and the low-speed rotor yokes, so that the magnetic flux leaking from the inner peripheral ends of the high-speed rotor yokes or the low-speed rotor yokes enters the interior of the T-shaped modulation ring, and then links with the magnetic flux generated by the corresponding low-speed rotor or high-speed rotor permanent magnets, thereby reducing the magnetic flux leakage at the inner peripheral ends of the rotor yokes, increasing the air gap magnetic density, and achieving the purpose of reducing torque ripple, increasing output torque, and torque density.

[0044] In the present invention, the N-pole permanent magnets and S-pole permanent magnets in the high-speed permanent magnet rotor 1 are circumferentially magnetized, and the magnetization directions are opposite. Specifically, the N-pole permanent magnets and S-pole permanent magnets of the high-speed permanent magnet rotor 1 are magnetized in the clockwise direction and the counterclockwise direction respectively in the cylindrical coordinate system; in addition, the N-pole permanent magnets and S-pole permanent magnets in the low-speed permanent magnet rotor 3 are also circumferentially magnetized, and the magnetization directions are opposite. Specifically, the N-pole permanent magnets and S-pole permanent magnets of the low-speed permanent magnet rotor 3 are magnetized in the clockwise direction and the counterclockwise direction respectively in the cylindrical coordinate system.

[0045] According to the present invention, the number of pole pairs P of the permanent magnets in the high-speed permanent magnet rotor 1h The number of pole pairs P of the permanent magnets in the low-speed permanent magnet rotor 3 l and the number of modulation pole pieces N of the T-shaped modulation ring 2 s satisfy the relationship: P h +P l =N s . In the illustrated embodiment, the T-shaped modulation ring 2 includes 25 T-shaped modulation pole pieces and 25 T-shaped non-magnetic composite pole pieces; the high-speed permanent magnet rotor 1 includes 12 high-speed rotor yokes, 6 N-pole permanent magnets and 6 S-pole permanent magnets; the low-speed permanent magnet rotor 3 includes 38 low-speed rotor yokes, 19 N-pole permanent magnets and 19 S-pole permanent magnets.

[0046] In the embodiments of the present invention, the radial air gap 4 and the axial air gap 5 can be 1-3 mm. Preferably, both the radial air gap 4 and the axial air gap 5 are 2 mm.

[0047] Referring to Figure 5 , using the above structure, the two magnetic paths of the magnetic gear are: high-speed rotor N-pole permanent magnet - high-speed rotor yoke - air gap - T-shaped modulation ring - air gap - low-speed rotor yoke - low-speed rotor S-pole permanent magnet - low-speed rotor yoke - air gap - T-shaped modulation ring - air gap - high-speed rotor yoke - high-speed rotor N-pole permanent magnet; high-speed rotor S-pole permanent magnet - high-speed rotor yoke - air gap - T-shaped modulation ring - air gap - low-speed rotor yoke - low-speed rotor N-pole permanent magnet - low-speed rotor yoke - air gap - T-shaped modulation ring - air gap - high-speed rotor yoke - high-speed rotor S-pole permanent magnet. The magnetic flux passing through the high-speed rotor yoke reaches the low-speed rotor yoke along the air gap, the T-shaped modulation ring, and the air gap, and links with the magnetic fluxes generated by the two adjacent permanent magnets with opposite polarities on the left and right, thereby driving the low-speed rotor. It should be understood that the air gap mentioned in the magnetic path here includes both the radial air gap and the axial air gap.

[0048] Therefore, in the present invention, by using the T-shaped modulation ring as the stator, and sleeving the high-speed rotor and the low-speed rotor on both sides of the modulation ring, the leakage magnetic fluxes at the inner peripheral ends of the high-speed rotor yoke and the low-speed rotor yoke can enter the interior of the T-shaped modulation ring and link with the magnetic fluxes generated by the low-speed rotor permanent magnets or the high-speed rotor permanent magnets, thereby reducing the leakage magnetic fluxes at the inner peripheral ends of the rotor yokes on both sides of the T-shaped modulation ring, that is, more magnetic fluxes will pass through the air gap to reach the rotor poles; at the same time, the high-speed rotor and the low-speed rotor rotate coaxially, and the axial magnetic flux coupling efficiency is high. Therefore, the present invention increases the air gap magnetic density, improves the gear output torque and the torque density. In addition, the T-shaped modulation ring of the present invention is bonded by a plurality of T-shaped modulation pole pieces and T-shaped non-magnetic composite pole pieces, which is easy to process, and the high-speed and low-speed rotors are sleeved on both sides of the modulation ring, and the structure is compact, which helps to realize the compact layout of the magnetic gear and the motor. Thus, the axial magnetic field modulation type magnetic gear adopting the T-shaped modulation ring structure of the present invention realizes multi-objective optimization and breaks through the technical limitations of the existing axial magnetic gears.

[0049] Next, the axial magnetic field modulation type magnetic gear applying the T-shaped modulation ring structure provided by the present invention will be further described with reference to an example.

[0050] In this example, the T-shaped modulation ring includes 25 T-shaped silicon steel sheet magnetic pole pieces and 25 T-shaped epoxy resin pole pieces. The high-speed permanent magnet rotor includes 12 high-speed rotor yokes, 6 N-pole permanent magnets and 6 S-pole permanent magnets. The low-speed permanent magnet rotor includes 38 low-speed rotor yokes, 19 N-pole permanent magnets and 19 S-pole permanent magnets. The radial air gap and the axial air gap are both 2 mm.

[0051] Refer to Figure 6 , keep one rotor of the magnetic gear fixed, and then gradually rotate the other rotor at a very small angle to obtain its static torque-angle characteristic. In this figure, LSR is the low-speed rotor and HSR is the high-speed rotor. It can be seen that the static torque-angle characteristic of the gear shows a periodic change, which conforms to the characteristics of a 6-pole structure.

[0052] Refer to Figure 7 , the magnetic gear performs a load movement to obtain the dynamic torque characteristic of the magnetic gear. It can be seen that the dynamic torque characteristic of the gear is stable, and the transmission ratio can be calculated as 3.22 by the ratio of the average torque of the LSR to the average torque of the HSR, which is approximately equal to the theoretical transmission ratio of 3.17 (the number of permanent magnet pole pairs of the low-speed permanent magnet rotor 19 divided by the number of permanent magnet pole pairs of the high-speed permanent magnet rotor 6). The simulation results are consistent with the topological structure.

[0053] Refer to Figure 8 and Figure 9 , in the air gap between the high-speed rotor and the stator, the 6th main harmonic is generated by the permanent magnets in the high-speed rotor, where the number of permanent magnet pole pairs is 6, which is equal to the harmonic order. After being modulated by the T-shaped modulation ring, the 19th harmonic is obtained, which is equal to the number of permanent magnet pole pairs of the low-speed rotor. Therefore, the magnetic flux generated by the low-speed rotor is coupled with the 19th harmonic after being modulated by the T-shaped modulation ring of the high-speed rotor, and then is driven to rotate.

[0054] Refer to Figure 10 and Figure 11 , in the air gap between the low-speed rotor and the stator, the 19th main harmonic is generated by the permanent magnets in the low-speed rotor, where the number of permanent magnet pole pairs is 19, which is equal to the harmonic order. After being modulated by the T-shaped modulation ring, the 6th harmonic is obtained, which is equal to the number of permanent magnet pole pairs of the high-speed rotor. Therefore, the magnetic flux generated by the high-speed rotor is coupled with the 6th harmonic after being modulated by the T-shaped modulation ring of the low-speed rotor, and thus rotates. It can be seen that Figures 6 to 11 the simulation results verify the effectiveness of the gear structure proposed by the present invention.

[0055] Refer to Figure 12 and Figure 13, by comparing the cross-sectional magnetic flux of the magnetic gear of the present invention using a T-shaped modulation ring with that of the existing magnetic gear using a traditional modulation ring, it can be seen that the magnetic gear of the present invention containing a T-shaped modulation ring has an obvious magnetic leakage coupling effect. Specifically, Figure 13 in [a certain situation], the magnetic leakage at the inner circumferential ends of the rotor yokes on both sides of the gear cannot be linked, while Figure 12 in [another situation], as indicated by the horizontal arrow (the vertical arrow represents the normal axial magnetic flux), the magnetic leakage at the inner circumferential ends of the high-speed and low-speed rotor yokes on both sides of the gear enters the T-shaped modulation ring, and thus the magnetic leakage at the inner circumferential ends of the yokes on both sides is linked through the T-shaped modulation ring, verifying that the present invention can achieve the recovery of magnetic leakage on both sides of the rotor.

[0056] Finally, it should be noted that the features mentioned and / or shown in the above description of the exemplary embodiments of the present invention can be combined in the same or similar manner into one or more other embodiments, combined with the features in other embodiments or replace the corresponding features in other embodiments. The technical solutions obtained through such combination or replacement should also be regarded as being included within the protection scope of the present invention.

Claims

1. An axially magnetic field modulated magnetic gear applying a T-type modulation ring structure, characterized in that: It includes a high-speed permanent magnet rotor, a low-speed permanent magnet rotor, and a T-shaped modulation ring as the stator; The T-shaped modulation ring includes a plurality of T-shaped magnetic modulation pole pieces and a plurality of T-shaped non-magnetic composite material pole pieces that are alternately arranged in the circumferential direction and adhesively bonded in sequence. The T-shaped magnetic modulation pole pieces and the T-shaped non-magnetic composite material pole pieces of the T-shaped modulation ring each include a first rod and a second rod that vertically extends from the middle of the first rod. All the first rods of the T-shaped modulation ring extend parallel to each other along the axial direction to form a ring, and all the second rods of the T-shaped modulation ring extend radially outward from the corresponding first rods; The high-speed permanent magnet rotor and the low-speed permanent magnet rotor are respectively used to be installed on a high-speed rotating shaft and a low-speed rotating shaft. The high-speed permanent magnet rotor includes a high-speed rotor iron core composed of a plurality of rotor yokes, and a plurality of N-pole permanent magnets and S-pole permanent magnets that are embedded between adjacent rotor yokes in the circumferential direction. The low-speed permanent magnet rotor includes a low-speed rotor iron core composed of a plurality of rotor yokes, and a plurality of N-pole permanent magnets and S-pole permanent magnets that are embedded between adjacent rotor yokes in the circumferential direction. The high-speed permanent magnet rotor and the low-speed permanent magnet rotor are both formed in the layout order of N-pole permanent magnet, rotor yoke, S-pole permanent magnet, and rotor yoke; The high-speed permanent magnet rotor and the low-speed permanent magnet rotor are respectively coaxially sleeved on the ring formed by the first rods of the T-shaped modulation ring on both sides of the second rods of the T-shaped modulation ring, and have a radial air gap with the first rods and an axial air gap with the second rods, thereby forming obliquely upward and obliquely downward magnetic fluxes that are at an angle to both the axial and radial directions. The leakage magnetic flux at the inner circumferential end of the rotor yokes of the high-speed permanent magnet rotor and the low-speed permanent magnet rotor can enter the T-shaped modulation ring, so as to modulate the magnetic flux through the T-shaped modulation ring.

2. The axial magnetic field modulation type magnetic gear applying a T-shaped modulation ring structure according to claim 1, wherein: The number of pole pairs P of the permanent magnet in the high-speed permanent magnet rotor h and the number of pole pairs P of the permanent magnet in the low-speed permanent magnet rotor l and the number of magnetic pole adjusting pieces N of the T-shaped modulation ring s satisfy the relationship: P h +P l =N s .

3. The axial magnetic field modulation type magnetic gear applying the T-shaped modulation ring structure according to claim 2, characterized in that: The T-shaped modulation ring includes 25 T-shaped magnetic modulation pole pieces and 25 T-shaped non-magnetic composite material pole pieces; the high-speed permanent magnet rotor includes 12 rotor yokes, 6 N-pole permanent magnets and 6 S-pole permanent magnets; the low-speed permanent magnet rotor includes 38 rotor yokes, 19 N-pole permanent magnets and 19 S-pole permanent magnets.

4. The axial magnetic field modulation type magnetic gear applying a T-shaped modulation ring structure according to claim 1 or 2, characterized in that: The N-pole permanent magnets and S-pole permanent magnets in the high-speed permanent magnet rotor are axially magnetized in the circumferential direction, and the magnetization directions are opposite; the N-pole permanent magnets and S-pole permanent magnets in the low-speed permanent magnet rotor are axially magnetized in the circumferential direction, and the magnetization directions are opposite.

5. The axial magnetic field modulation type magnetic gear applying a T-shaped modulation ring structure according to claim 1 or 2, characterized in that: The radial air gap and the axial air gap are 1 - 3 mm.

6. The axial magnetic field modulation type magnetic gear applying the T-shaped modulation ring structure according to claim 5, characterized in that: Both the radial air gap and the axial air gap are 2 mm.

7. The axial magnetic field modulated magnetic gear applying a T-shaped modulation ring structure according to claim 1 or 2, characterized in that: The T-shaped magnetic modulation pole pieces of the T-shaped modulation ring are laminated by silicon steel sheets.

8. The axial magnetic field modulated magnetic gear applying a T-shaped modulation ring structure according to claim 1 or 2, characterized in that: The T-shaped non-magnetic composite material pole pieces of the T-shaped modulation ring are made of epoxy resin.

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