GB2590863A

GB2590863A - Disc-type magnetic gear using flux-focusing flux modulation apparatus

Info

Publication number: GB2590863A
Application number: GB2103639.7A
Authority: GB
Inventors: Yang Chaojun; Zhu Li; Peng Zhizhuo; Tai Jiangxi; Gao Yang; Yang Fan; Wang Kai
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2019-10-31
Filing date: 2020-04-30
Publication date: 2021-07-07
Anticipated expiration: 2040-04-30
Also published as: GB202103639D0; GB2590863B

Abstract

The invention relates to the technical field of transmission in mechanical engineering, in particular to a disc type magnetic gear using a magnetism gathering type magnetism adjusting device. The magnetic gear is composed of a driving disc assembly, a driven disc assembly and a magnetism gathering type magnetism adjusting device assembly, and is characterized in that: a magnetism adjusting block of the magnetism gathering type magnetism adjusting device adopts a structure with ½ periodic sine sides and an approximate isosceles trapezoid cross section, in combination with a mechanical structure installed in a matching way, to enhance the reliability of the magnetic gear. Different connection modes can be selected according to the different base materials of the magnetism adjusting block. In order to prevent magnetic leakage at the end, a transverse soft magnetic material is added, the magnetism adjusting device can simultaneously realize the magnetism adjusting and gathering effects, improving the magnetism adjusting performance, and enhancing the magnetism gathering capacity. The permanent magnets of the driving disc and the driven disc are both arranged in a 90-degree Halbach arrangement mode or a compact arrangement mode and the like with higher magnetic energy density. The present invention enhances the torque density of the magnetic gear by the design of the structure of the magnetism adjusting device and the arrangement of the permanent magnet, so that the magnetic gear is widely applied to a high torque working environment.

Description

DISC-TYPE MAGNETIC GEAR USING FLUX-FOCUSING FLUX

MODULATION APPARATUS

Technical Field

The present invention relates to the technical field of transmission in mechanical engineering, and is a magnetic gear with non-contact connection, specifically a disc-type magnetic gear using a flux-focusing flux modulation apparatus. It can be applied to non-contact transmission systems with high torque and high and low speed transmission.

Background

In industrial production, mechanical gears are widely used in various transmission systems due to the advantages of fixed transmission ratio, wide applicable speed and load ranges, and long service life. However, the vibration and noise in the transmission process of mechanical gears are relatively large. As the gears are in contact with each other, serious gear wear is caused. In addition, mechanical gears do not have overload protection. These shortcomings reduce the transmission performance of mechanical gears, restricting its use in particular working environments. With the development of modern technology and the improvement of the performance of permanent magnetic materials, many scholars have proposed the solution of using magnetic gear structures instead of traditional mechanical gears Magnetic gears achieve the purpose of transmission through magnetic coupling forces that attract and repel each other, and realize the non-contact transmission of force and torque through the coupling of magnetic fields in the air gap. Compared with traditional mechanical gears, magnetic gears have the advantages of non-contact transmission, overload protection and high transmission efficiency. In high-performance magnetic gears, a flux modulation pole piece is introduced. The permanent magnets in the inner and outer rotors are modulated by the flux modulation pole piece, to generate a harmonic magnetic field which has the same number of pole pairs of the permanent magnets of the rotors in the inner and outer air gaps, so as to improve the utilization of the permanent magnets, thereby greatly increasing the transmission efficiency of the magnetic gears In Invention Patent No. 201710461909.0, Jiangsu University discloses an air gap adjustable magnetic gear with a side sinusoidal flux modulation apparatus, in which a side sinusoidal structure of the flux modulation block is used on the cylindrical magnetic gear, the 1/2 cycle of sine curve applied by the flux modulation block changes in the axial direction, and during the process of air gap adjustment, the 1/2 cycle of sine curve has different modulation effects. No flux focusing approach is adopted at the end of the permanent magnet, which results in much flux leakage. It fails to take into consideration the method of changing the arrangement of permanent magnets to achieve high torque density transmission of magnetic gears.

A Novel Magnetic Gear: Toward a Higher Torque Density in IEEE TRANSACTIONS ON MAGNETICS, VOL. 51, NO. 11, NOVEMBER 2015 discloses a theoretical model of a high-density magnetic gear that can focus flux both axially and transversely, where the axial flux-focusing part is a sector-shaped ring with a certain thickness, and the cross section of the transverse flux-focusing part is also a sector-shaped ring, which is easily sucked out by the axial force between the permanent magnet discs or thrown out of the magnetic gear by the huge centrifugal force during operation. It also fails to indicate the specific material selection and molding method for the flux modulation block and the specific structure for supporting the flux modulation block.

Summary

In order to overcome the shortcomings of insufficient utilization of the magnetic energy of the permanent magnets in the current application of magnetic gears, the inability of the structure of the flux modulation block to meet the working requirements, and the flux leakage of magnetic gears, and by adding a flux-focusing part made of a soft magnetic material at the end of the permanent magnet, adopting 1/2 cycle of sine curve at the side of the flux modulation part of the flux modulation block, adopting an approximately isosceles trapezoid cross section for the flux modulation part, and adopting an arrangement of permanent magnets with high magnetic energy density, the present invention provides a disc-type magnetic gear using a flux-focusing flux modulation apparatus.

A disc-type magnetic gear using a flux-focusing flux modulation apparatus comprises a driving disc assembly, a driven disc assembly and a flux modulation apparatus assembly, wherein the flux modulation apparatus assembly is mounted between the driving disc assembly and the driven disc assembly, the flux modulation apparatus assembly comprises a flux modulation block, a flux-modulation-block tray, a flux-modulation-block support and an end cap, the flux modulation block is engaged with and mounted to the flux-modulation-block support through the flux-modulation-block tray, the end cap is connected to the flux-modulation-block tray by a rivet, so as to completely fix the flux modulation block, the driven disc assembly comprises a driven shaft, a driven-shaft sleeve, a driven-disc base, driven-disc permanent magnets and screws, a left end of the driven shaft is connected to the driven-shaft sleeve by a key, a left side of the driven-shaft sleeve is connected to the driven-disc base by a screw, and the driven-disc permanent magnets are closely arranged and are surface-mounted on the driven-disc base; the driving disc assembly comprises a driving shaft, a driving-shaft sleeve, a driving-disc base, driving-disc permanent magnets and screws. The installation method for the driving disc is the same as that for the driven disc.

ns flux modulation blocks are provided, n, being equal to a sum of a driving-disc pole pair number P, and a driven-disc pole pair number P2.

An axial part made of a soft magnetic material of the flux modulation block in the flux modulation apparatus provides a function of magnetic field modulation by concentrating magnetic induction lines, and a transverse part made of a soft magnetic material added to the flux modulation block concentrates magnetic induction lines to effectively reduce flux leakage at ends of the permanent magnets, so that a flux-focusing flux modulation block is formed, and purposes of magnetic field modulation and enhancing a torque density of the gear are achieved at the same time. The axial part of the flux modulation block is a flux modulation part, and the transverse part is a flux-focusing part. A side of the flux modulation part is 1/2 cycle of sine curve, enhancing a flux modulation effect. With the approximately isosceles trapezoid cross section structure of the flux-focusing part, the flux modulation block is engaged with and mounted to the flux-modulation-block tray, support and the like, to enhance reliability of the flux modulation apparatus.

The present invention further comprises the following: a thickness of the flux modulation part of the flux modulation block is k and is the same as a thickness of the flux-modulation-block tray, an expression indicating that a side of the flux modulation block is Asox, 1/2 cycle of sine curve is y= and a side of a slot of the flux-modulation-block tray adopts 1/2 cycle of sine curve that matches the side of the flux modulation block. A flux-focusing part of the flux modulation block of the disc-type gear is added. The flux-focusing part has a length of 0 or L. When the flux-focusing part has a length of 0, the flux modulation apparatus includes only the flux modulation part. When the flux-focusing part has a length of /I, thicknesses of the driving disc and the driven-disc permanent magnets are h, thicknesses of the driving-disc base and the driven-disc base are hfe, a thickness of the h flux-modulation-block tray is, and considering strength of the flux modulation block, generally let L2(h + h)-h" so that the flux modulation block achieves flux modulation and flux-focusing effects at the same time.

When the transverse flux-focusing part has a length of 0, the flux-modulation-block support is in a semi-closed form and may provide a function of isolating magnetic induction lines to a certain extent to reduce the flux leakage; the flux modulation apparatus comprises three parts: a flux-modulation-block tray, a flux-modulation-block support and a flux modulation block, and the flux-modulation-block tray is connected to the flux-modulation-block support, so as to fix the flux modulation block. When the flux-focusing part of the flux modulation block has a length of L, the flux modulation apparatus comprises four parts: a flux-modulation-block tray, a flux-modulation-block support, a flux modulation block and an end cap, the slot of the flux-modulation-block tray is engaged with and mounted to the side of the flux modulation part of the flux modulation block, a slot of the flux-modulation-block support adopts an approximately isosceles trapezoid cross section to be engaged with and mounted to the flux-focusing part of the flux modulation block, and a side of the end cap is provided with a boss having an approximately isosceles trapezoid cross section and engaged with a groove of the flux-modulation-block support.

A base body of the flux modulation apparatus comprises a flux-modulation-block tray, a flux-modulation-block support and an end cap, which are made of the same material. The base body is made of epoxy resin, nylon material, austenitic stainless steel, or other non-magnetically permeable material, and the flux-modulation-block support, the flux-modulation-block tray and the end cap are connected by a countersunk head rivet or by welding.

When the flux-focusing part of the flux modulation block has a length of L, the flux modulation apparatus can achieve flux modulation and flux-focusing effects at the same time. The flux modulation block is made of improved ferrite or other soft magnetic material, and manufactured by 3D printing technology or casting technology. The flux-focusing part adopts an approximately isosceles trapezoid cross section, to enhance the strength reliability of the flux modulation block. The permanent magnets on the driving-disc base and the driven-disc base are closely arranged in 900 Halbach array, and the magnetic field strength in a working air gap of the magnetic gear is enhanced by making use of a single-side flux-focusing characteristic of the Halbach array. A base angle of an approximately isosceles trapezoid cross section of a side of the slot of the flux-modulation-block support and a base angle of the approximately isosceles trapezoid cross section of the flux-focusing part of the flux modulation block are both a, being 600-750 The advantages of the present invention lie in that the flux modulation block of the present invention has two parts: the flux modulation block and the flux-focusing part, and by adopting a flux-focusing arrangement of permanent magnets, flux modulation and flux-focusing effects are achieved at the same time. The side of the axial flux-focusing part of the flux modulation block adopts 1/2 cycle of sine curve, and the transverse part adopts an approximately isosceles trapezoid cross section, so that the structural strength of the flux modulation apparatus is improved through its own structure, thereby avoiding the use of connecting bridges to increase the strength, and reducing eddy current loss. The flux-modulation-block support is in a semi-closed form so as to reduce the flux leakage, and improve the utilization of permanent magnets. The flux-modulation-block support and the flux modulation block may be fixed by either of structural engagement and mechanical connection, thereby enhancing the stability of the flux modulation apparatus. In addition, the use of the disc-type structure not only can adjust the air gap, but also can enable the 1/2 cycle of sine curve at the side to have a consistent optimization effect for magnetic field modulation. The flux modulation blocks with different materials and connection methods and of which the flux-focusing part has a length of 0 or L can be selected according to different occasions, so as to meet the requirements of different working conditions with high torque density requirements.

Brief Description of the Drawings

The present invention will be further described below with reference to the accompanying drawings and embodiments FIG. 1 is a schematic assembly view of a disc-type magnetic gear using a flux-focusing flux modulation apparatus.

FIG. 2 is a 1/4 cross-sectional view of the overall three-dimensional structure when the flux-focusing part has a length of 0 according to an embodiment.

FIG. 3 is a three-dimensional structural diagram of a flux-modulation-block tray according to an embodiment.

FIG. 4 is a three-dimensional structural diagram of a single flux modulation block of ferrite or other material when the flux-focusing part has a length of 0 according to an embodiment.

FIG. 5 is a three-dimensional structural diagram of a single flux modulation block of silicon steel sheet material when the flux-focusing part has a length of 0 according to an embodiment.

FIG. 6 is a three-dimensional structural diagram of a flux-modulation-block support when the flux-focusing part has a length of 0 according to an embodiment.

FIG. 7 is a three-dimensional structural diagram of a flux modulation apparatus assembly when the flux-focusing part has a length of 0 according to an embodiment.

FIG. 8 is a three-dimensional structural diagram of a single flux modulation block when the flux-focusing part has a length of L according to an embodiment.

FIG. 9 is a three-dimensional structural diagram of the flux modulation block being engaged with and mounted to the flux-modulation-block tray when the flux-focusing part has a length of L according to an embodiment.

FIG. 10 is a three-dimensional structural diagram of a flux-modulation-block support when the flux-focusing part has a length of L according to an embodiment.

FIG. 11 is a three-dimensional structural diagram of an end cap when the flux-focusing part has a length of L according to an embodiment.

FIG. 12 is a structural diagram of a flux modulation apparatus assembly when the flux-focusing part has a length of L according to an embodiment.

FIG. 13 is a schematic diagram of driving-disc and driven-disc permanent magnets arranged in Halbach array according to an embodiment.

FIG. 14 is a schematic diagram of driving-disc and driven-disc permanent magnets arranged closely according to an embodiment.

FIG. 15 is 1/2 cycle of sine curve at a side of the flux modulation part.

FIG. 16 is a schematic diagram of a flux-focusing part having an approximately isosceles trapezoid cross section.

FIG. 17 is a 1/4 cross-sectional view of the overall three-dimensional structure when the flux-focusing part has a length of L according to an embodiment.

When the flux-focusing part has a length of 0: 1 -driving shaft; 2 -driving-shaft sleeve; 3 -driving-disc base; 4 -driving-disc permanent magnet; 5 -flux modulation block; 6 -driven-disc permanent magnet; 7 -driven shaft; 8 -driven-shaft sleeve; 9 -driven-disc base; 10 -flux-modulation-block tray; 11 -rivet; 12-flux-modulation-block support.

When the flux-focusing part has a length of L: 1 -driving shaft; 2 -driving-shaft sleeve; 3 -driving-disc base; 4 -driving-disc permanent magnets; 6 -driven-disc permanent magnets; 7 -driven shaft; 8 -driven-shaft sleeve; 9 -driven-disc base; 10 -flux-modulation-block tray; 13 -flux-modulation-block support; 14 -flux modulation block; 15 -end cap; 16 -rivet.

Detailed Description of the Embodiments

As shown in FIG. 1, a disc-type magnetic gear using a flux-focusing flux modulation apparatus comprises a driving disc assembly 1, a flux modulation apparatus assembly II and a driven disc assembly III.

The driving disc assembly includes a driving shaft 1, a driving-shaft sleeve 2, a driving-disc base 3, permanent magnets 4 and screws. A right end of the driving shaft is connected to the driving-shaft sleeve by a key. A right side of the driving-shaft sleeve is connected to the driving-disc base 3 by a screw. The driving-disc permanent magnets 4 are closely arranged, with no gap between the permanent magnets, and are surface-mounted on the driving-disc base 3. The driven disc assembly includes a driven shaft 7, a driven-shaft sleeve 8, a driven-disc base 9, driven-disc permanent magnets 6 and screws. A left end of the driven shaft is connected to the driven-shaft sleeve 8 by a key. A left side of the driven-shaft sleeve 8 is connected to the driven-disc base 9 by a screw. The driven-disc permanent magnets 6 are also closely arranged, and are surface-mounted on the driven-disc base 9.

When the flux-focusing part has a length of 0, i.e., the flux modulation block does not have a flux-focusing part, the flux modulation apparatus assembly comprises a flux modulation block 5, a flux-modulation-block tray 10, a flux-modulation-block support 12 and a rivet 11. 1/2 cycle of sine curve at a side of the flux modulation block 5 is made coincide with 1/2 cycle of convex sine curve at a side of a slot of the flux-modulation-block tray 10, so that the flux modulation block 5 is engaged with and mounted to the flux-modulation-block tray 10. The flux-modulation-block support 12 is connected to the flux-modulation-block tray 10 by the rivet 11, so as to enclose and completely fix the flux modulation block 5. During operation, the driving-disc base 3 rotates, the driving-disc permanent magnets 4 on the driving-disc base 3 generate a magnetic field, and by making use of the high permeability of the flux modulation block 5, the magnetic field generated by the driving-disc base 3 is modulated. Harmonics of the modulated magnetic field interact with a magnetic field generated by the driven-disc permanent magnets 6 on the driven-disc base 9, to drive the driven disc to rotate.

When the flux-focusing part has a length of L, the flux modulation apparatus assembly comprises a flux modulation block 14, a flux-modulation-block tray 10, a flux-modulation-block support 13, an end cap 15 and a rivet 16. 1/2 cycle of sine curve at a side of the flux modulation part of the flux modulation block 14 is made coincide with 1/2 cycle of convex sine curve at a side of the slot of the flux-modulation-block tray 10, and an approximately isosceles trapezoid surface of the flux-focusing part of the flux modulation block 14 coincides with an approximately isosceles trapezoid surface at the bottom of a groove of the flux-modulation-block support 13. The flux-modulation-block support 13 is connected to the end cap 15 by the rivet 16, so as to enclose and completely fix the flux modulation block 14. For example, the base material of the flux modulation block is a non-magnetically permeable metallic material such as stainless steel, and a welding method can be used. During operation, the driving-disc base 3 rotates, the driving-disc permanent magnets 4 on the driving-disc base 3 generate a magnetic field, and by making use of the high permeability of the flux modulation block 14, the magnetic field generated by the driving-disc base 3 is modulated by the flux modulation part of the flux modulation block. Harmonics of the modulated magnetic field interact with a magnetic field generated by the driven-disc permanent magnets 6 on the driven-disc base 9, to drive the driving-disc base 9 to rotate. Meanwhile, owing to its high permeability, the flux modulation part of the flux modulation block 14 suppresses the flux leakage, and enhances the density of the magnetic field between the driving-disc base 3 and the driving-disc base 9.

In the flux modulation apparatus, by the adoption of the structure of 1/2 cycle of sine curve at the side of the axial flux-focusing part of the flux modulation block 5 and the flux modulation block 14, the slot gap of the flux-modulation-block tray 10, and the adoption of 1/2 cycle of sine curve which is complementary to the side of the axial flux-focusing part, the contact area between the flux modulation block 5 or the flux modulation block 14 and the flux-modulation-block tray 10 is increased, and the displacement caused by the axial force is overcome to a large extent. The smooth curve reduces the generation of connecting bridges, and enhances the strength and rigidity of the flux modulation apparatus. The flux-focusing part adopts an approximately isosceles trapezoid cross section, which is different from an isosceles trapezoid in that its upper and lower bases are arcs. When the arcs and sides form an approximately isosceles trapezoid, the base angle is a. In this way, the contact area between the flux modulation block 14 and the flux-modulation-Nock support 13 is increased, and the displacement caused by the radial force is well overcome, thereby further enhancing the strength and rigidity of the flux modulation apparatus The flux modulation block 5 can be made of a silicon steel sheet or ferrite material, and fabricated by sheet stacking or casting molding. The flux modulation block 14 is made of an improved soft magnetic material such as improved ferrite or iron-based amorphous alloy, and is fabricated by casting or 3D printing technology. Thus, the obstacle that traditional processing methods cannot process ferrite of complex shapes is overcome. In addition, the structural design of the flux modulation block itself overcomes the shortcoming of insufficient flux modulation of 3D printing to a certain extent. The flux-modulation-block support, the flux-modulation-block tray and the end cap are made of a non-magnetically permeable material, such as nylon, plastic, epoxy resin and stainless steel. The flux-modulation-block supports 12 and 13 and the flux-modulation-block tray 10 form a cup-shaped structure, thereby reducing the flux leakage, enhance the flux-focusing performance, and improving the utilization of permanent magnets.

Claims

Claims What is claimed is: 1. A disc-type magnetic gear using a flux-focusing flux modulation apparatus, comprising a driving disc assembly and a driven disc assembly, wherein the driven disc assembly comprises a driven shaft, a driven-shaft sleeve, a driven-disc base, driven-disc permanent magnets and a screw, a left end of the driven shaft is connected to the driven-shaft sleeve by a key, a left side of the driven-shaft sleeve is connected to the driven-disc base by the screw, and the driven-disc permanent magnets are closely arranged and are surface-mounted on the driven-disc base; the driving disc assembly comprises a driving shaft, a driving-shaft sleeve, a driving-disc base, driving-disc permanent magnets and a screw, a right end of the driving shaft is connected to the driving-shaft sleeve by a key, a right side of the driving-shaft sleeve is connected to the driving-disc base by the screw, and the driving-disc permanent magnets are closely arranged and are surface-mounted on the driving-disc base, characterized by further comprising a flux modulation apparatus assembly, wherein the flux modulation apparatus assembly is mounted between the driving disc assembly and the driven disc assembly, the flux modulation apparatus assembly comprises a flux modulation block, a flux-modulation-block tray, and a flux-modulation-block support, and the flux modulation block is engaged with and mounted to the flux-modulation-block support through the flux-modulation-block tray, so as to fix the flux modulation block.
2. The disc-type magnetic gear using the flux-focusing flux modulation apparatus according to claim 1, characterized in that the flux-modulation-block support is in a semi-closed form and provides a function of isolating magnetic induction lines to reduce a flux leakage, an axial part made of a soft magnetic material of the flux modulation block provides a function of magnetic field modulation by concentrating magnetic induction lines, and forms a flux modulation part; 1/2 cycle of sine curve at a side of the flux modulation block is made coincide with 1/2 cycle of convex sine curve at a side of a slot of the flux-modulation-block tray, so that the flux modulation block is engaged with and mounted to the flux-modulation-block tray, and the flux-modulation-block support is connected to the flux-modulation-block tray, so as to enclose and completely fix the flux modulation block; and the flux modulation block is made of a silicon steel sheet or ferrite soft magnetic material, and fabricated by a sheet stacking or casting process.
3. The disc-type magnetic gear using the flux-focusing flux modulation apparatus according to claim 2, characterized in that a thickness of the flux modulation part of the flux modulation block is hand is equal to a thickness of the flux-modulation-block tray, an expression indicating that the side of the flux modulation block is 1/2 cycle of sine curve is y = A sin cox and a side of the slot of the flux-modulation-block tray adopts 1/2 cycle of sine curve that matches the side of the flux modulation block
4. A disc-type magnetic gear using a flux-focusing flux modulation apparatus, comprising a driving disc assembly and a driven disc assembly, wherein the driven disc assembly comprises a driven shaft, a driven-shaft sleeve, a driven-disc base, driven-disc permanent magnets and a screw, a left end of the driven shaft is connected to the driven-shaft sleeve by a key, a left side of the driven-shaft sleeve is connected to the driven-disc base by the screw, and the driven-disc permanent magnets are closely arranged and are surface-mounted on the driven-disc base; the driving disc assembly comprises a driving shaft, a driving-shaft sleeve, a driving-disc base, driving-disc permanent magnets and a screw, a right end of the driving shaft is connected to the driving-shaft sleeve by a key, a right side of the driving-shaft sleeve is connected to the driving-disc base by the screw, and the driving-disc permanent magnets are closely arranged and are surface-mounted on the driving-disc base, characterized in that a flux modulation apparatus assembly is mounted between the driving disc assembly and the driven disc assembly, the flux modulation apparatus assembly comprises a flux modulation block, a flux-modulation-block tray, a flux-modulation-block support and an end cap, the flux modulation block is engaged with and mounted to the flux-modulation-block support through the flux-modulation-block tray, and the end cap is connected to the flux-modulation-block tray, so as to completely fix the flux modulation block.
5. The disc-type magnetic gear using the flux-focusing flux modulation apparatus according to claim 4, characterized in that an axial part made of a soft magnetic material of the flux modulation block in the flux modulation apparatus assembly provides a function of magnetic field modulation by concentrating magnetic induction lines, and a transverse part made of a soft magnetic material added to the flux modulation block concentrates magnetic induction lines to effectively reduce flux leakage at ends of the permanent magnets, so that a flux-focusing flux modulation block is formed, while achieving magnetic field modulation and enhancement of a torque density of the gear; the axial part of the flux modulation block is a flux modulation part, and the transverse part is a flux-focusing part; a side of the flux modulation part is 1/2 cycle of sine curve, improving a flux modulation effect; the flux-focusing part adopts an approximately isosceles trapezoid cross section, which is different from an isosceles trapezoid in that its upper and lower bases are arcs, and the arcs and sides form an approximately isosceles trapezoid to obtain a base angle of a, increasing a contact area between the flux modulation block and the flux-modulation-block support, a slot of the flux-modulation-block tray is engaged with and mounted to the side of the flux modulation part of the flux modulation block, a slot of the flux-modulation-block support adopts an approximately isosceles trapezoid cross section to be engaged with and mounted to the flux-focusing part of the flux modulation block, a side of the end cap is provided with a boss having an approximately isosceles trapezoid cross section and engaged with a groove of the flux-modulation-block support, to enhance reliability of the flux modulation apparatus assembly; and the flux modulation block is made of an improved ferrite or other soil magnetic material, and manufactured by 3D printing technology or casting technology.
6. The disc-type magnetic gear using the flux-focusing flux modulation apparatus according to claim 5, characterized in that a thickness of the flux modulation part of the flux modulation h block is and is equal to a thickness of the flux-modulation-block tray, an expression = indicating that a side of the flux modulation block is 1/2 cycle of sine curve is yA sincox and a side of the slot of the flux-modulation-block tray adopts 1/2 cycle of sine curve that matches the side of the flux modulation block; when the flux-focusing part has a length of L, thicknesses of the driving disc and the driven-disc permanent magnets are h, thicknesses of the driving-disc base and the driven-disc base are h, a thickness of the flux-modulation-block tray is, and considering a strength of the flux modulation block, L 2 (hie + h)+ h" so that the flux modulation block achieves both flux modulation and flux-focusing effects, and a base angle of an approximately isosceles trapezoid cross section of a side of the slot of the flux-modulation-block support and a base angle of the approximately isosceles trapezoid cross section of the flux-focusing part of the flux modulation block are both a, a being 600-750
7. The disc-type magnetic gear using the flux-focusing flux modulation apparatus according to claim I or 4, characterized in that the permanent magnets on the driving-disc base and the driven-disc base are closely arranged in a 900 Halbach array, and a magnetic field strength in a working air gap of the magnetic gear is enhanced by making use of a single-side flux-focusing characteristic of the Halbach array.
8. The disc-type magnetic gear using the flux-focusing flux modulation apparatus according to claim 1 or 4, characterized in that ns flux modulation blocks are provided, ns. being equal to a sum of a driving-disc pole pair number P1 and a driven-disc pole pair number P2.
9. The disc-type magnetic gear using the flux-focusing flux modulation apparatus according to claim I, characterized in that a base body of the flux modulation apparatus assembly comprises the flux-modulation-block tray and the flux-modulation-block support, the base body is made of epoxy resin, nylon material or austenitic stainless steel non-magnetically permeable material, and the flux-modulation-block support and the flux-modulation-block tray are connected by a countersunk head rivet or by welding
10. The disc-type magnetic gear using the flux-focusing flux modulation apparatus according to claim 4, characterized in that a base body of the flux modulation apparatus assembly comprises the flux-modulation-block tray, the flux-modulation-block support and the end cap, the base body is made of epoxy resin, nylon material or austenitic stainless steel non-magnetically permeable material, and the flux-modulation-block support, the flux-modulation-block tray and the end cap are connected by a countersunk head rivet or by welding.