A permanent magnet array

Abstract

The application relates to the technical field of permanent magnet arrays, and particularly provides a permanent magnet array which comprises a first permanent magnet unit and a second permanent magnet unit, the first permanent magnet unit is close to the air gap side of a motor, the high-temperature resistance of main magnets is improved, the second permanent magnet unit is close to the motor shell side, and the main magnets are easy to dissipate heat; the first permanent magnet unit and the second permanent magnet unit are both formed by a plurality of main magnet circumferential arrays; in the first permanent magnet unit, an auxiliary magnetic pole is connected in series between two adjacent main magnets; two auxiliary magnetic poles are arranged between two adjacent longitudinal main magnets of the permanent magnet array to form a closed magnetic field; the permanent magnet array adopting the circumferential array magnetic field can be uniformly distributed in the motor air gap, can effectively reduce magnetic flux leakage, and can improve the electromagnetic conversion efficiency of the motor; the main magnets are manufactured by combining ferrite material and neodymium-iron-boron material, the use of rare earth materials is reduced, and the economic cost is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet array technology, and more specifically to a permanent magnet array. Background Technology

[0002] A permanent magnet array is a magnetic structure formed by arranging multiple permanent magnets in a specific geometric manner. It is designed to optimize the magnetic field distribution or enhance the magnetic field strength in a specific area. In motors, permanent magnet arrays mainly drive the motor by providing a stable magnetic field.

[0003] A published Chinese patent, publication number CN111799054B, discloses a permanent magnet array. The array consists of several identical equilateral triangular magnets arranged sequentially. The magnetization directions of adjacent equilateral triangular magnets are different, causing the magnetic field to converge on one side. The number of magnets, Z, satisfies Z = 4*n + 3 (n ∈ N*). In use, the magnetization directions of 2-4 adjacent magnets in the permanent magnet array converge. Through the convergence of local N-pole or S-pole magnetic fields, the magnetic lines of force are superimposed, increasing the magnetic flux density on one side of the permanent magnet array. This enhances the magnetic field on one side of the guide rail surface, increasing the magnetic field strength and effective area above the array. However, while this patent increases the magnetic flux density on one side by converging local N-pole or S-pole magnetic fields, the increased magnetic field on one side may be accompanied by increased leakage flux on the other side, affecting the electromagnetic conversion efficiency of the motor. Existing technologies also employ Halbach-shaped permanent magnet arrays to increase air gap magnetic flux density. For example, a published Chinese patent, CN115775667A, discloses a Halbach permanent magnet array composed of alternating first and second permanent magnet blocks. The first permanent magnet block has a rectangular upper section and a trapezoidal lower section in its cross-section, with the waist of the trapezoid being an arc. The upper rectangle and lower trapezoid of the first permanent magnet block's cross-section are symmetrical about an axis. The second permanent magnet block... The upper part of the cross-section is rectangular and the lower part is arc-shaped. The rectangle at the top and the arc at the bottom of the cross-section of the second permanent magnet block are symmetrical about the axis. When arranged, the first permanent magnet block magnetized vertically upward, the second permanent magnet block magnetized horizontally to the right, the first permanent magnet block magnetized vertically downward, and the second permanent magnet block magnetized horizontally to the left are arranged in a close fit, with every four blocks forming a magnetic field distribution cycle. This method can greatly enhance the magnetic field on one side of the permanent magnet array and greatly weaken the magnetic field on the other side, but the problem of magnetic leakage still exists.

[0004] In addition, existing technologies often use high-grade permanent magnet materials for the entire permanent magnet array to improve the air gap magnetic flux density and increase the motor's power output. High-grade permanent magnet materials refer to permanent magnet materials with high energy product and coercivity, typically high-performance neodymium iron boron (NdFeB) permanent magnets. NdFeB is a rare-earth permanent magnet material mainly composed of rare-earth elements neodymium (Nd), iron (Fe), and boron (B), with rare-earth elements accounting for approximately 25%–35%, iron for approximately 65%–75%, and boron for approximately 1%. High-grade permanent magnet materials have high remanence, large magnetic induction coercivity, and high energy product. Although this can improve the air gap magnetic flux density of the motor, this method requires a large amount of rare-earth materials, which greatly increases the motor design cost. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a permanent magnet array. This invention employs a circular array of permanent magnets. Each pair of main magnets located along the longitudinal direction of the permanent magnet array, in conjunction with auxiliary magnetic poles, forms a closed magnetic field. This, in turn, creates several closed magnetic fields in a circular array around the permanent magnet array. These circular array closed magnetic fields are uniformly distributed in the motor air gap, effectively reducing magnetic leakage and improving the electromagnetic conversion efficiency of the motor. Furthermore, this invention uses a combination of ferrite and neodymium iron boron materials to manufacture the main magnets, reducing the use of rare earth materials and effectively lowering economic costs. Compared to traditional technologies that use only high-grade permanent magnet materials, ferrite materials are lighter and more advantageous. This invention increases the air gap magnetic flux density on the air gap side of the motor, thereby increasing the motor's power density. Furthermore, since the heat source is mainly concentrated on the working air gap side during motor operation, this invention places the main magnet made of ferrite material close to the working air gap side. Compared to neodymium iron boron (NdFeB), ferrite has better high-temperature resistance, effectively extending the motor's service life. This invention also places the main magnet made of NdFeB material close to the motor housing side, as NdFeB material facilitates heat dissipation, improving the motor's application performance. This invention addresses the problem of magnetic leakage caused by the single-sided magnetic field enhancement method in existing technologies, and also solves the problem of high cost associated with using only high-grade permanent magnet materials to increase the motor's air gap magnetic flux density and power output.

[0006] To achieve the above and other related objectives, the present invention provides a permanent magnet array, including a first permanent magnet unit disposed at both ends of the permanent magnet array and a second permanent magnet unit disposed in the middle of the permanent magnet array, wherein the first permanent magnet unit is close to the air gap side of the motor and the second permanent magnet unit is close to the housing side of the motor.

[0007] The first permanent magnet unit and the second permanent magnet unit are both composed of a circular array of several main magnets. The main magnets located in the same longitudinal direction of the permanent magnet array have the same magnetization direction, and the two adjacent main magnets in the same circumferential direction of the permanent magnet array have opposite magnetization directions.

[0008] In the first permanent magnet unit, auxiliary magnetic poles are connected in series between two adjacent main magnets. The magnetization direction of the auxiliary magnetic poles forms a 90° angle with the magnetization direction of the two adjacent main magnets. The magnetization directions of the two auxiliary magnetic poles located in the same longitudinal direction of the permanent magnet array are opposite. The main magnets constituting the first permanent magnet unit are made of ferrite material, and the main magnets constituting the second permanent magnet unit are made of neodymium iron boron material.

[0009] The two main magnets located in adjacent longitudinal directions of the permanent magnet array form a closed magnetic field through two auxiliary magnetic poles.

[0010] In one embodiment of the present invention, the main magnet is a radially segmented sector block, and the magnetization direction of several main magnets located in the same circumferential direction of the permanent magnet array is continuously deflected along the circumferential tangential direction.

[0011] In one embodiment of the present invention, the ring width of the second permanent magnet unit is greater than the ring width of the first permanent magnet unit, and water channels are reserved between the two sides of the first permanent magnet unit and the second permanent magnet unit.

[0012] In one embodiment of the present invention, the auxiliary magnetic pole is made of neodymium iron boron material.

[0013] In one embodiment of the present invention, the number of main magnets constituting the first permanent magnet unit is the same as the number of main magnets constituting the second permanent magnet unit, and satisfies N=2n+1 (n is an integer and n≥1).

[0014] In one embodiment of the present invention, the number of the second permanent magnet units is two, and the main magnet of a single second permanent magnet unit is connected to the main magnet of an adjacent first permanent magnet unit.

[0015] As described above, the permanent magnet array of the present invention has the following beneficial effects:

[0016] 1. The present invention adopts a permanent magnet array in a circular array manner. By the main magnet and auxiliary magnetic poles located on every two adjacent longitudinal directions of the permanent magnet array, a closed magnetic field is formed. This forms several closed magnetic fields in a circular array around the permanent magnet array. These closed magnetic fields in the circular array are evenly distributed in the air gap of the motor, which can effectively reduce magnetic leakage and improve the electromagnetic conversion efficiency of the motor.

[0017] 2. Since the heat source is mainly concentrated on the working air gap side of the motor during operation, this invention places the main magnet made of ferrite material close to the working air gap side of the motor. Compared with neodymium iron boron, ferrite has better high temperature resistance and effectively extends the service life of the motor. This invention also places the main magnet made of neodymium iron boron material close to the motor housing side. Neodymium iron boron material is easy to dissipate heat, improving the application effect of the motor.

[0018] 3. This invention uses a combination of ferrite and neodymium iron boron materials to manufacture the main magnet, which can reduce the use of rare earth materials and effectively reduce economic costs. Compared with the traditional technology that uses high-grade permanent magnet materials, ferrite materials are lighter and can help increase the air gap magnetic flux density on the air gap side of the motor, thereby increasing the power density of the motor.

[0019] 4. The present invention provides a water channel between the two sides of the first permanent magnet unit and the second permanent magnet unit. The water channel can be used to lay water pipes for water cooling and heat dissipation, which improves the performance of the motor and makes the internal structure of the motor more compact.

[0020] 5. Since the magnetic properties of ferrite materials are significantly affected at low temperatures, there is a risk of irreversible demagnetization. In contrast, the magnetic properties of neodymium iron boron (NdFeB) materials do not change significantly at low temperatures, and their coercivity is much greater than that of ferrite. Therefore, this invention connects auxiliary magnetic poles made of NdFeB material in series between ferrites. The NdFeB auxiliary magnetic poles can not only form a closed magnetic field with the main magnet, but also help to magnetize the adjacent ferrite main magnets, thereby improving the magnetic properties of ferrite materials at low temperatures.

[0021] 6. This invention employs a permanent magnet array with a circular magnetic field, which can be uniformly distributed in the motor's air gap, effectively reducing magnetic leakage and improving the motor's electromagnetic conversion efficiency. The invention places the main magnet made of ferrite material close to the air gap side of the motor's operation, improving the main magnet's high-temperature resistance. The invention places the main magnet made of neodymium iron boron material close to the motor's housing side, facilitating heat dissipation. The invention uses a combination of ferrite and neodymium iron boron materials to manufacture the main magnet, reducing the use of rare earth materials and effectively lowering economic costs. The pre-reserved water channel allows for the installation of water pipes for water cooling, improving motor performance. Attached Figure Description

[0022] Figure 1 The diagram shown is a structural schematic of the permanent magnet array disclosed in this invention.

[0023] Figure 2 The diagram shown is a partial exploded view of the permanent magnet array disclosed in this invention.

[0024] Figure 3 The diagram shown is a front view of the permanent magnet array disclosed in this invention.

[0025] Figure 4 The diagram shown is a top view of the permanent magnet array disclosed in this invention.

[0026] Component designation explanation

[0027] First permanent magnet unit 1; Second permanent magnet unit 2; Auxiliary magnetic pole 3; Waterway 4. Detailed Implementation

[0028] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0029] Please see Figures 1 to 4 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of the invention, should fall within the scope of the disclosed technical content. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0030] Example 1, please refer to Figures 1-2 This embodiment provides a permanent magnet array, including a first permanent magnet unit 1 located at both ends of the array and a second permanent magnet unit 2 located in the middle of the array. Both the first and second permanent magnet units are composed of a circular array of several main magnets. Each main magnet is a radially segmented sector block, and the magnetization direction of several main magnets located in the same circumferential direction of the array continuously deflects tangentially along the circumference. The number of main magnets constituting the first permanent magnet unit 1 is the same as the number of main magnets constituting the second permanent magnet unit 2, and satisfies N = 2n + 1 (n is an integer, and n ≥ 1). There are two second permanent magnet units 2, with each main magnet of a single second permanent magnet unit 2 connected to the main magnet of an adjacent first permanent magnet unit 1.

[0031] The main magnet constituting the first permanent magnet unit 1 is made of ferrite material, and the main magnet constituting the second permanent magnet unit 2 is made of neodymium iron boron material. The first permanent magnet unit 1 is close to the air gap side of the motor, and the second permanent magnet unit 2 is close to the housing side of the motor. Since the heat source is mainly concentrated on the working air gap side of the motor when it is working, this invention places the main magnet made of ferrite material close to the working air gap side of the motor. Compared with neodymium iron boron, ferrite has better high temperature resistance and effectively extends the service life of the motor. This invention places the main magnet made of neodymium iron boron material close to the housing side of the motor. Neodymium iron boron material is easy to dissipate heat and improves the application effect of the motor.

[0032] Please see Figures 3-4 , Figures 3-4The middle arrow indicates the magnetization direction; multiple main magnets located in the same longitudinal direction of the permanent magnet array have the same magnetization direction, while two adjacent main magnets in the same circumferential direction of the permanent magnet array have opposite magnetization directions; in the first permanent magnet unit 1, auxiliary magnetic poles 3 are connected in series between two adjacent main magnets, and the magnetization direction of the auxiliary magnetic poles 3 forms a 90° angle with the magnetization direction of the two adjacent main magnets. The magnetization directions of the two auxiliary magnetic poles 3 located in the same longitudinal direction of the permanent magnet array are opposite; the main magnets located in two adjacent longitudinal directions of the permanent magnet array form a closed magnetic field through the two auxiliary magnetic poles 3. This invention adopts a circumferential array of permanent magnets, in which the main magnets and auxiliary magnetic poles in every two adjacent longitudinal directions of the permanent magnet array cooperate to form a closed magnetic field, thereby forming several closed magnetic fields in a circumferential array around the permanent magnet array. These closed magnetic fields in the circumferential array are evenly distributed in the air gap of the motor, which can effectively reduce magnetic leakage and improve the electromagnetic conversion efficiency of the motor.

[0033] The ring width of the second permanent magnet unit 2 is greater than that of the first permanent magnet unit 1. Water channels 4 are reserved between the two sides of the first permanent magnet unit 1 and the second permanent magnet unit 2. Water pipes can be laid in the water channels for water cooling and heat dissipation, which improves the performance of the motor and makes the internal structure of the motor more compact.

[0034] The auxiliary magnetic pole 3 is made of neodymium iron boron (NdFeB). Since the magnetic properties of ferrite materials are significantly affected at low temperatures, leading to the risk of irreversible demagnetization, while the magnetic properties of NdFeB materials do not change significantly at low temperatures and their coercivity is much greater than that of ferrite, this invention connects auxiliary magnetic poles made of NdFeB material in series between the ferrites. These NdFeB auxiliary magnetic poles not only help form a closed magnetic field with the main magnets but also contribute to the magnetization of adjacent ferrite main magnets, thereby improving the magnetic properties of the ferrite material at low temperatures.

[0035] Example 2, based on Example 1, provides a permanent magnet array for a small motor, including the following implementation parameters:

[0036] Number of main magnets: N=3 (n=1), with 3 main magnets used in each of the first permanent magnet unit 1 and the second permanent magnet unit 1;

[0037] The main magnet has the following dimensions: radial length of 20mm, circumferential width of 15mm, and thickness of 8mm.

[0038] The following materials are included:

[0039] First permanent magnet unit 1 (ferrite): remanence Br=0.4T, coercivity Hc=250kA / m;

[0040] Second permanent magnet unit 2 (neodymium iron boron): Br=1.2T, Hc=1000kA / m;

[0041] Auxiliary magnetic pole 3 (neodymium iron boron): Br=1.2T, dimensions are 5mm×5mm×8mm;

[0042] Waterway 4 design: ring width difference is 3mm, waterway 4 width is 2mm, and the internal copper pipe diameter is 1.5mm.

[0043] The implementation effects of this embodiment include:

[0044] Magnetic field performance: The air gap magnetic flux density is increased to 0.9T (compared to 0.6T in the traditional design), and magnetic leakage is reduced by 30%;

[0045] Heat dissipation efficiency: The water-cooling system with channel 4 reduces the temperature on the air gap side by 15℃, and the temperature rise of the motor during continuous operation is ≤40K;

[0046] Cost and low-temperature performance: Rare earth content is reduced by 40%, and the demagnetization rate of ferrite at low temperature (-30℃) is reduced from 20% to 5%.

[0047] Example 3, based on Example 1, provides a permanent magnet array for a medium-sized motor, including the following implementation parameters:

[0048] Number of main magnets: N=5 (n=2), with 5 main magnets in each of the first and second permanent magnet units;

[0049] Main magnet dimensions: radial length of sector block 30mm, circumferential width 20mm, thickness 10mm.

[0050] The following materials are included:

[0051] First permanent magnet unit 1 (ferrite): Br=0.42T, Hc=260kA / m;

[0052] Second permanent magnet unit 2 (neodymium iron boron): Br=1.25T, Hc=1100kA / m;

[0053] Auxiliary magnetic pole 3 (neodymium iron boron): Br=1.25T, dimensions are 8mm×8mm×10mm;

[0054] Waterway 4 design: the ring width difference is 5mm, the width of waterway 4 is 3mm, and the built-in spiral waterway has a flow velocity of 0.5m / s.

[0055] The implementation effects of this embodiment include:

[0056] Magnetic field performance: Air gap magnetic flux density reaches 1.1T, torque output is increased by 25%, and magnetic leakage is reduced by 40%;

[0057] Heat dissipation and lifespan: The heat dissipation efficiency of the NdFeB housing side is improved by 50%, and the lifespan of the ferrite air gap side is extended to 100,000 hours;

[0058] Lightweight and cost reduction: Overall weight reduced by 20%, material costs reduced by 35%.

[0059] Example 4, based on Example 1, provides a permanent magnet array for large high-power motors, including the following implementation parameters:

[0060] Number of main magnets: N=7 (n=3), with 7 main magnets in each of the first and second permanent magnet units;

[0061] Main magnet dimensions: radial length of sector block 50mm, circumferential width 30mm, thickness 15mm.

[0062] The following materials are included:

[0063] First permanent magnet unit 1 (ferrite): Br=0.45T, Hc=280kA / m;

[0064] Second permanent magnet unit 2 (neodymium iron boron): Br=1.3T, Hc=1200kA / m;

[0065] Auxiliary magnetic pole 3 (neodymium iron boron): Br=1.3T, dimensions are 10mm×10mm×15mm;

[0066] Waterway 4 design: the ring width difference is 8mm, the width of waterway 4 is 5mm, and it integrates a dual-circulation water cooling system with a flow rate of 2L / min.

[0067] The implementation effects of this embodiment include:

[0068] Magnetic field and power density: The air gap magnetic flux density reaches 1.4T, and the power density is increased to 5kW / kg (the traditional one is 3kW / kg).

[0069] Anti-demagnetization capability: The demagnetization rate of ferrite is only 3% at low temperature (-40℃), and the coercivity of neodymium iron boron assisted magnetic poles is significantly superior;

[0070] Heat dissipation and stability: The dual water cooling system ensures that the temperature rise under peak load is ≤30K and the motor efficiency is ≥95%.

[0071] Based on the specific implementation data of Examples 2 to 4, it can be seen that the permanent magnet array provided by this invention is applicable to small, medium, and large motors, with a wide range of applications and excellent market application value. Furthermore, the permanent magnet array provided by this invention significantly improves the air gap magnetic flux density and reduces leakage flux in terms of magnetic field performance. In terms of heat dissipation efficiency, the water channel 4 can be equipped with various water-cooling structures, reducing the temperature on the air gap side and decreasing the temperature rise during continuous motor operation. Regarding cost and low-temperature performance, the addition of ferrite materials reduces the amount of rare earth elements used, effectively lowering the economic cost of motor manufacturing. For medium and large motors, the addition of ferrite materials also achieves motor lightweighting. Considering that the magnetic properties of ferrite materials are significantly affected at low temperatures, leading to the risk of irreversible demagnetization, while the magnetic properties of neodymium iron boron materials do not change significantly at low temperatures, the auxiliary magnetic poles made of neodymium iron boron materials connected in series between the ferrites in this invention reduce the demagnetization rate of the ferrites at low temperatures.

[0072] In summary, this invention employs a permanent magnet array with a circular magnetic field, which can be uniformly distributed in the motor's air gap, effectively reducing magnetic leakage and improving the motor's electromagnetic conversion efficiency. The main magnet, made of ferrite material, is positioned close to the air gap side of the motor's operation, improving its high-temperature resistance. The main magnet, made of neodymium iron boron material, is positioned close to the motor's housing side, facilitating heat dissipation. The use of a combination of ferrite and neodymium iron boron materials in the main magnet manufacturing reduces the use of rare earth materials, effectively lowering economic costs. The reserved water channel 4 allows for the installation of water pipes for water cooling, improving motor performance. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial applicability.

[0073] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A permanent magnet array, characterized in that: It includes a first permanent magnet unit (1) located at both ends of the permanent magnet array and a second permanent magnet unit (2) located in the middle of the permanent magnet array; the first permanent magnet unit (1) is close to the air gap side of the motor, and the second permanent magnet unit (2) is close to the housing side of the motor. The first permanent magnet unit (1) and the second permanent magnet unit (2) are both composed of a circular array of several main magnets. The main magnets located in the same longitudinal direction of the permanent magnet array have the same magnetization direction, and the two adjacent main magnets located in the same circumferential direction of the permanent magnet array have opposite magnetization directions. The main magnets constituting the first permanent magnet unit (1) are made of ferrite material, and the main magnets constituting the second permanent magnet unit (2) are made of neodymium iron boron material. In the first permanent magnet unit (1), an auxiliary magnetic pole (3) is connected in series between two adjacent ferrite main magnets. The magnetization direction of the auxiliary magnetic pole (3) is at a 90° angle to the magnetization direction of the two adjacent main magnets. The magnetization directions of the two auxiliary magnetic poles (3) located in the same longitudinal direction of the permanent magnet array are opposite. The two adjacent main magnets in the permanent magnet array form a closed magnetic field through the cooperation of the two auxiliary magnetic poles (3).

2. The permanent magnet array according to claim 1, characterized in that: The main magnet is a radially segmented sector block, and the magnetization direction of several main magnets located in the same ring direction of the permanent magnet array is continuously deflected along the circumferential tangential direction.

3. The permanent magnet array according to claim 2, characterized in that: The ring width of the second permanent magnet unit (2) is greater than that of the first permanent magnet unit (1), and water channels (4) are reserved between the two sides of the first permanent magnet unit (1) and the second permanent magnet unit (2).

4. The permanent magnet array according to claim 1, characterized in that: The auxiliary magnetic pole (3) is made of neodymium iron boron material.

5. The permanent magnet array according to claim 1, characterized in that: The number of main magnets constituting the first permanent magnet unit (1) is the same as the number of main magnets constituting the second permanent magnet unit (2), and satisfies N=2n+1, where n is an integer and n≥1.

6. The permanent magnet array according to claim 1, characterized in that: The number of the second permanent magnet unit (2) is two, and the main magnet of a single second permanent magnet unit (2) is connected to the main magnet of the adjacent first permanent magnet unit (1).

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