Permanent magnet magnetic circuit device and rotary magnetic refrigerator

Abstract

This utility model discloses a permanent magnet circuit device and a rotary magnetic refrigerator. The permanent magnet circuit device includes a shaft, a stator, and a rotor; the rotor includes a housing, a first magnetic unit, and a second magnetic unit; the housing has a cylindrical structure; the housing is fitted over the stator, with a first accommodating space between them; the housing has an inner sidewall and an outer sidewall, with a second accommodating space between the inner and outer sidewalls for accommodating the first and second magnetic units; the first and second magnetic units are symmetrically arranged about the centerline of the shaft; the first magnetic unit includes n layers of magnets distributed radially along the housing, and the second magnetic unit includes n layers of magnets distributed radially along the housing, where n is a positive integer greater than or equal to 2; the n layers of magnets include a first layer and a second layer. The permanent magnet circuit device has a relatively large intermediate gap volume.

Description

Technical Field

[0001] This utility model relates to a permanent magnet magnetic circuit device and a rotary magnetic refrigeration machine. Background Technology

[0002] With societal progress, refrigeration technology is playing an increasingly important role, holding a pivotal position in various fields such as household refrigeration, commercial refrigeration, industrial refrigeration, and medical refrigeration.

[0003] Currently, many refrigeration technologies employ gas compression refrigeration. On the one hand, gas compression refrigeration has relatively low energy efficiency. On the other hand, it often uses hydrofluorocarbons (HFCs) as refrigerants, and HFCs are greenhouse gases with a global warming potential thousands of times greater than carbon dioxide. The widespread use of gas compression refrigeration carries the potential for environmental damage; for example, the emission of Freon used can deplete the ozone layer, contributing to the greenhouse effect. Therefore, the search for new refrigeration technologies is urgently needed.

[0004] Magnetic refrigeration technology, as a novel refrigeration technology that is green, environmentally friendly, energy-efficient, and reliable, has attracted much attention from researchers. Magnetic refrigeration technology is based on the magnetocaloric effect of magnetic materials, utilizing thermodynamic cycles to achieve refrigeration. The magnetocaloric effect refers to the heat absorption and release phenomenon exhibited by magnetocaloric materials in a changing magnetic field. Magnetic refrigeration technology often uses metals such as Gd or La(Fe,Si). 13 Solid materials such as compounds are used as refrigerants and will not pollute the environment. Magnetic refrigeration technology generally uses an active magnetic cold storage cycle as a thermodynamic cycle, which has high energy efficiency, far exceeding that of gas compression refrigeration.

[0005] The development of magnetic refrigeration technology is inseparable from changing magnetic field systems, with permanent magnet systems being the most common. Double-layer Halbach cylindrical permanent magnet systems are widely used in magnetic refrigerators, where the excitation and demagnetization of the magnetic refrigeration material are achieved through the rotation of the inner Halbach magnet array. However, this type of permanent magnet system suffers from a small gap volume in the middle, resulting in low heat exchange efficiency. Furthermore, the assembly process of the magnets in this system is complex, requiring the overcoming of strong magnetic forces to rearrange and assemble the magnets. Utility Model Content

[0006] In view of this, one objective of this utility model is to provide a permanent magnet circuit device. It has a relatively large central gap volume, resulting in high heat exchange efficiency. Furthermore, its assembly process is relatively simple. Another objective of this utility model is to provide a rotary magnetic refrigerator.

[0007] The present invention achieves the above objectives by adopting the following technical solution.

[0008] On the one hand, this utility model provides a permanent magnet circuit device, including a shaft, a stator and a rotor;

[0009] The stator has a cylindrical structure and is sleeved on the outside of the shaft. The inner wall of the stator is fixed to the outer wall of the shaft. The two ends of the shaft are located outside the two ends of the stator, respectively.

[0010] The rotor includes a housing, a first magnetic unit, and a second magnetic unit; the housing has a cylindrical structure; the housing is sleeved on the outside of the stator, and there is a first receiving space between the two; the housing has an inner sidewall and an outer sidewall, and there is a second receiving space between the inner sidewall and the outer sidewall for accommodating the first magnetic unit and the second magnetic unit.

[0011] Based on the number, shape, and size of the magnets, the first magnetic unit and the second magnetic unit are symmetrically arranged about the center line of the axis. The first magnetic unit includes n layers of magnets distributed radially along the shell, and the second magnetic unit includes n layers of magnets distributed radially along the shell, where n is a positive integer greater than or equal to 2. The n layers of magnets include a first layer of magnets and a second layer of magnets.

[0012] The first layer of magnets includes m first magnets of the same shape and size. These first magnets are all fan-shaped and are arranged in sequence along the perimeter of the shell, close to the inner wall of the shell, and m is an even number greater than or equal to 6.

[0013] The second layer of magnets includes (m-2) second magnets of the same shape and size. These second magnets are all fan-shaped and are arranged sequentially along the perimeter of the shell, close to the side of the first layer of magnets away from the inner wall of the shell. The two first magnets at both ends of the first layer of magnets are not provided with second magnets on the side away from the inner wall of the shell.

[0014] Such permanent magnet circuit devices can increase the volume of the primary storage space, thereby increasing the volume of the magnetic refrigeration bed assembly, which can accommodate more magnetic working fluid and improve heat exchange efficiency. The assembly of such permanent magnet circuit devices is also simpler. Furthermore, it can reduce energy consumption.

[0015] In this invention, n is preferably a positive integer greater than or equal to 3, for example, n is 4. m is preferably 8.

[0016] In the cross-sectional schematic diagram of the permanent magnet circuit device of this utility model, the magnetization directions of the magnets in the first magnetic unit and the magnets in the second magnetic unit are not symmetrical. Specifically, the magnetization direction of the magnets in the first magnetic unit is generally from the inner wall of the shell to the outer wall, and the magnetization direction of the magnets in the second magnetic unit is generally from the outer wall of the shell to the inner wall.

[0017] The magnets in the first and second magnetic units can be samarium cobalt magnets or neodymium iron boron magnets, preferably neodymium iron boron magnets. The grade of the neodymium iron boron magnet can be N50 or N52. In this invention, all magnets have the same grade.

[0018] According to the permanent magnet circuit device of this utility model, preferably, n is a positive integer greater than or equal to 3; the n-layer magnet group further includes a third layer magnet group;

[0019] The third magnet group comprises (m-4) third magnets of identical shape and size. These third magnets are fan-shaped and are arranged sequentially along the circumference of the shell, close to the side of the second magnet group away from the inner wall of the shell. No third magnets are placed on the side of the two second magnets at both ends of the second magnet group away from the inner wall of the shell. This improves the performance of the permanent magnet circuit device.

[0020] In this invention, each magnet is fan-shaped. The length of the outer arc of the first magnet in the first layer of magnet group is the same as the length of the inner arc of the second magnet in the second layer of magnet group, and the length of the outer arc of the second magnet is the same as the length of the inner arc of the third magnet in the third layer of magnet group.

[0021] According to the permanent magnet circuit device of this utility model, preferably, n is 4 and m is 8. This can improve the performance of the permanent magnet circuit device. In this utility model, when n is 4, the first magnetic unit includes 4 layers of magnet groups distributed radially along the shell, and the second magnetic unit includes 4 layers of magnet groups distributed radially along the shell; when m is 8, the first layer of magnet groups includes 8 first magnets of the same shape and size.

[0022] According to the permanent magnet circuit device of this utility model, preferably:

[0023] The first magnetic unit is configured as a plurality of units, which are stacked along the central axis of the housing;

[0024] The second magnetic unit is configured as a plurality of units, which are stacked along the central axis of the housing. This is beneficial for improving the performance of the permanent magnet circuit device.

[0025] According to the permanent magnet circuit device of this utility model, preferably, the first magnetic unit is set to three or more; the second magnetic unit is set to three or more; the number of the first magnetic unit and the number of the second magnetic unit are equal. Preferably, the first magnetic unit stacked is four or more, and the second magnetic unit stacked is four or more.

[0026] According to the permanent magnet circuit device of this utility model, preferably, the rotor further includes a fixing member with a receiving cavity, the fixing member being located within the second receiving space; the first magnet, the second magnet, and the third magnet are all embedded within the fixing member. This secures each magnet. The fixing member can be a steel structure. The shape and size of the receiving cavity of the fixing member match the shape and size of the corresponding magnet.

[0027] According to the permanent magnet circuit device of this utility model, preferably, it further includes a magnetic refrigeration bed assembly, which comprises multiple magnetic refrigeration beds, all of which are fan-shaped and arranged in a ring, located within a first accommodating space between the shell and the stator. The interiors of the multiple magnetic refrigeration beds are all configured with hollow structures to accommodate the magnetic working fluid. Through holes are provided at both ends of these magnetic refrigeration beds for connecting heat exchange fluid pipelines. This increases the accommodating space of the hollow structure of the magnetic refrigeration bed, allowing for the accommodation of more magnetic working fluid, improving heat exchange efficiency, and enhancing operating efficiency.

[0028] According to the permanent magnet circuit device of this utility model, preferably, it further includes two bearings; the bearings have an annular structure; the two bearings are respectively located at two ends of the housing, configured to allow the rotor to rotate around the stator. This allows only the rotor to rotate, reducing energy consumption. It also includes a bearing housing that matches the bearing.

[0029] According to the permanent magnet circuit device of this utility model, preferably, it further includes two opposing bases; the bases are in the form of a ring; the two bases are respectively connected to the two ends of the stator and the shaft. The bearing housing is connected to the base. By setting the bases, dust and other contaminants can be prevented from entering the rotor, thus protecting the rotor. During operation, neither the bases nor the bearing housings rotate.

[0030] On the other hand, this utility model also provides a rotary magnetic refrigerator, including the permanent magnet circuit device as described above.

[0031] The permanent magnet circuit device of this invention has a larger central gap volume, which allows for a larger volume of the magnetic refrigeration bed assembly, accommodating more magnetic working fluid. This increased volume generates significant cooling, improving the refrigeration performance of the magnetic refrigerator, including its cooling temperature range, cooling power, and overall operating efficiency. Furthermore, the assembly process of this permanent magnet circuit device is relatively simple. In addition, this permanent magnet circuit device consists of a stator and a rotor. Compared to the overall rotation of existing permanent magnet circuit devices, this invention only rotates the rotor, requiring less energy and improving the energy utilization rate of the magnetic refrigerator. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of a permanent magnet circuit device according to the present invention.

[0033] Figure 2 for Figure 1 A longitudinal cross-sectional schematic diagram.

[0034] Figure 3 for Figure 1 A schematic diagram of the cross-section.

[0035] Figure 4 This is a schematic diagram of the magnetic refrigeration bed assembly of this utility model.

[0036] Figure 5 This is a schematic diagram of the magnetic field distribution of the permanent magnet circuit device of this utility model.

[0037] The annotations in the attached figures are explained as follows:

[0038] 1-Shaft; 2-Base; 3-Stator;

[0039] 5-Rotor, 51-First magnetic unit, 5111-First magnet A, 5112-First magnet B, 5113-First magnet C, 5114-First magnet D, 5115-First magnet E, 5116-First magnet F, 5117-First magnet G, 5118-First magnet H;

[0040] 5121 - Second magnet A, 5122 - Second magnet B, 5123 - Second magnet C, 5124 - Second magnet D, 5125 - Second magnet E, 5126 - Second magnet F;

[0041] 5131 - Third magnet A, 5132 - Third magnet B, 5133 - Third magnet C, 5134 - Third magnet D;

[0042] 5141 - Fourth Magnet A, 5142 - Fourth Magnet B;

[0043] 52-Second magnetic unit, 5211-First magnet A', 5212-First magnet B', 5213-First magnet C', 5214-First magnet D', 5215-First magnet E', 5216-First magnet F', 5217-First magnet G', 5218-First magnet H';

[0044] 5221-Second magnet A', 5222-Second magnet B', 5223-Second magnet C', 5224-Second magnet D', 5225-Second magnet E', 5226-Second magnet F';

[0045] 5231-Third magnet A', 5232-Third magnet B', 5233-Third magnet C', 5234-Third magnet D';

[0046] 5241 - Fourth magnet A', 5242 - Fourth magnet B';

[0047] 6-Magnetic refrigeration bed assembly; 61-First magnetic refrigeration bed; 62-Second magnetic refrigeration bed; 63-Third magnetic refrigeration bed; 64-Fourth magnetic refrigeration bed; 7-Bearing. Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0049] Example 1

[0050] Figure 1 This is a schematic diagram of the overall structure of a permanent magnet circuit device according to the present invention. Figure 2 for Figure 1 A longitudinal cross-sectional schematic diagram. Figure 3 for Figure 1 A schematic diagram of the cross-section. Figure 4 This is a schematic diagram of the magnetic refrigeration bed assembly. Figure 5 This is a schematic diagram of the magnetic field distribution of the permanent magnet circuit device of this utility model.

[0051] The permanent magnet circuit device of this invention is mainly applicable to rotary magnetic refrigerators, such as... Figures 1 to 4 As shown, the permanent magnet circuit device in this embodiment includes a shaft 1, a base 2, a stator 3, a rotor 5, a magnetic cooling bed assembly 6, and a bearing 7.

[0052] The stator 3 has a cylindrical structure and is fitted onto the outside of the shaft 1. The inner wall of the stator 3 is fixed to the outer wall of the shaft 1. Both ends of the shaft 1 protrude beyond the ends of the stator. The stator 3 can be made of high-permeability steel. During operation, the stator remains stationary.

[0053] The rotor 5 includes a housing, a first magnetic unit 51, a second magnetic unit 52, and a fixing member. The housing has a cylindrical structure. The housing is fitted onto the outside of the stator 3, with a first accommodating space between them. This first accommodating space is used to accommodate the magnetic refrigeration bed assembly 6. The larger volume of the first accommodating space (i.e., the larger volume of the central gap) allows for a larger accommodating space for the magnetic refrigeration bed assembly 6, enabling it to hold more magnetic working fluid and improve heat exchange efficiency.

[0054] The housing has an inner wall and an outer wall, and a second receiving space between the inner wall and the outer wall for accommodating the first magnetic unit 51, the second magnetic unit 52 and the fixing member.

[0055] Based solely on the number, shape, and size of the magnets, the first magnetic unit 51 and the second magnetic unit 52 are symmetrically arranged about the center line of axis 1. The first magnetic unit 51 includes n layers of magnets distributed radially along the shell, and similarly, the second magnetic unit 52 includes n layers of magnets distributed radially along the shell. Here, n is a positive integer greater than or equal to 2, preferably a positive integer greater than or equal to 3; the n-layer magnet group includes a first layer, a second layer, and a third layer. For example, specifically, n is 4, and the n-layer magnet group includes a first layer, a second layer, a third layer, and a fourth layer.

[0056] In the first magnetic unit 51,

[0057] The first layer of magnets comprises m first magnets of identical shape and size. These first magnets are all fan-shaped and are arranged sequentially along the circumference of the shell, close to the inner wall of the shell, where m is an even number greater than or equal to 6; for example, m is 8. The eight first magnets are named A5111, B5112, C5113, D5114, E5115, F5116, G5117, and H5118.

[0058] The second magnet group comprises (m-2) second magnets of identical shape and size. These second magnets are fan-shaped and are arranged sequentially along the circumference of the shell, close to the side of the first magnet group away from the inner wall of the shell. No second magnets are placed on the side of the two first magnets at both ends of the first magnet group away from the inner wall of the shell. When m is 8, the second magnet group comprises 6 second magnets: A5121, B5122, C5123, D5124, E5125, and F5126.

[0059] The third magnet group consists of (m-4) third magnets of identical shape and size. These third magnets are fan-shaped and are arranged sequentially along the circumference of the shell, close to the side of the second magnet group away from the inner wall of the shell. No third magnets are placed on the side of the two second magnets at both ends of the second magnet group away from the inner wall of the shell. When m is 8, the third magnet group consists of 4 third magnets: A5131, B5132, C5133, and D5134.

[0060] The fourth magnet group comprises (m-6) fourth magnets of identical shape and size. These fourth magnets are all fan-shaped and are arranged sequentially along the circumference of the shell, close to the side of the third magnet group away from the inner wall of the shell. No fourth magnets are arranged on the side of the two third magnets at the ends of the third magnet group away from the inner wall of the shell. When m is 8, the fourth magnet group comprises two fourth magnets, namely fourth magnet A5141 and fourth magnet B5142.

[0061] That is, the number of magnets in the first, second, third, and fourth magnet groups decreases sequentially in an arithmetic sequence.

[0062] In the first magnetic unit 51, the magnetization directions of the first magnet, the second magnet, the third magnet and the fourth magnet are generally from the inner wall of the shell to the outer wall of the shell.

[0063] by Figure 3 The horizontal center line on the paper is the x-axis. Magnets A5111, B5112, C5113, and D5114 are symmetrically distributed with respect to magnets H5118, G5117, F5116, and E5115 about the x-axis, respectively. The magnetization direction of magnet D5114 makes a 10° angle with the x-axis, magnet C5113 makes a 20° angle, magnet B5112 makes a 30° angle, and magnet A5111 makes a 40° angle. That is, the farther a magnet is from the x-axis, the larger the angle between it and the x-axis.

[0064] by Figure 3 The horizontal center line on the paper is the x-axis. Second magnets A5121, B5122, and C5123 are symmetrically distributed with respect to second magnets F5126, E5125, and D5124 about the x-axis, respectively. The magnetization direction of second magnet C5123 makes a 20° angle with the x-axis, the magnetization direction of second magnet B5122 makes a 30° angle with the x-axis, and the magnetization direction of second magnet A5121 makes a 40° angle with the x-axis.

[0065] by Figure 3 The horizontal center line on the paper is the x-axis. Third magnets A5131 and B5132 are symmetrically distributed with respect to third magnets D5134 and C5133 about the x-axis, respectively. The magnetization direction of third magnet B5132 makes a 30° angle with the x-axis, and the magnetization direction of third magnet A5131 makes a 40° angle with the x-axis.

[0066] by Figure 3The horizontal center line on the paper is the x-axis, and the fourth magnet A5141 and the fourth magnet B5142 are symmetrically distributed about the x-axis. The magnetization direction of the fourth magnet A5141 makes an angle of 40° with the x-axis.

[0067] Multiple first magnetic units 51 are configured, and the multiple first magnetic units 51 are stacked along the central axis of the housing. For example, there are three or more first magnetic units 51.

[0068] In the second magnetic unit 52,

[0069] The first layer of magnets comprises m first magnets of identical shape and size. These first magnets are all fan-shaped and are arranged sequentially along the circumference of the shell, close to the inner wall of the shell, where m is an even number greater than or equal to 6; for example, m is 8. The eight first magnets are named A'5211, B'5212, C'5213, D'5214, E'5215, F'5216, G'5217, and H'5218.

[0070] The second magnet group comprises (m-2) second magnets of identical shape and size. These second magnets are fan-shaped and are arranged sequentially along the circumference of the shell, close to the side of the first magnet group furthest from the inner wall of the shell. No second magnets are placed on the side of the two first magnets at the ends of the first magnet group furthest from the inner wall of the shell. When m is 8, the second magnet group comprises 6 second magnets: A'5221, B'5222, C'5223, D'5224, E'5225, and F'5226.

[0071] The third magnet group consists of (m-4) third magnets of identical shape and size. These third magnets are fan-shaped and are arranged sequentially along the circumference of the shell, close to the side of the second magnet group away from the inner wall of the shell. No third magnets are placed on the side of the two second magnets at both ends of the second magnet group away from the inner wall of the shell. When m is 8, the third magnet group consists of 4 third magnets: A'5231, B'5232, C'5233, and D'5234.

[0072] The fourth magnet group comprises (m-6) fourth magnets of identical shape and size. These fourth magnets are all fan-shaped and are arranged sequentially along the circumference of the shell, close to the side of the third magnet group away from the inner wall of the shell. No fourth magnets are arranged on the side of the two third magnets at the ends of the third magnet group away from the inner wall of the shell. When m is 8, the fourth magnet group comprises two fourth magnets, namely fourth magnet A'5241 and fourth magnet B'5242.

[0073] Multiple second magnetic units 52 are provided, and the multiple second magnetic units 52 are stacked along the central axis of the shell. There are more than three second magnetic units 52; the number of first magnetic units 51 and second magnetic units 52 are equal.

[0074] In this embodiment, although the magnets in the first magnetic unit 51 and the second magnetic unit 52 are symmetrically distributed in number, shape, and size, the magnetization directions of the magnets are not symmetrically distributed. For example... Figure 3 As shown, in the second magnetic unit 52, the magnetization direction of each magnet is generally from the outer wall of the shell to the inner wall of the shell.

[0075] by Figure 3 The horizontal center line on the paper is the x-axis. Magnets A'5211, B'5212, C'5213, and D'5214 are symmetrically distributed with respect to magnets H'5218, G'5217, F'5216, and E'5215 about the x-axis, respectively. The magnetization direction of magnet D'5214 makes an angle of 10° with the x-axis, magnet C'5213 ​​makes an angle of 20°, magnet B'5212 makes an angle of 30°, and magnet A'5211 makes an angle of 40°.

[0076] by Figure 3 The horizontal center line on the paper is the x-axis. Second magnets A'5221, B'5222, and C'5223 are symmetrically distributed with respect to second magnets F'5226, E'5225, and D'5224 about the x-axis, respectively. The magnetization direction of second magnet C'5223 makes an angle of 20° with the x-axis, the magnetization direction of second magnet B'5222 makes an angle of 30° with the x-axis, and the magnetization direction of second magnet A'5221 makes an angle of 40° with the x-axis.

[0077] by Figure 3 The horizontal center line on the paper is the x-axis. The third magnets A'5231 and B'5232 are symmetrically distributed with respect to the third magnets D'5234 and C'5233 about the x-axis, respectively. The magnetization direction of the third magnet B'5232 makes an angle of 30° with the x-axis, and the magnetization direction of the third magnet A'5231 makes an angle of 40° with the x-axis.

[0078] by Figure 3 The horizontal center line on the paper is the x-axis, and the fourth magnet A'5241 and the fourth magnet B'5242 are symmetrically distributed about the x-axis. The magnetization direction of the fourth magnet A'5241 makes an angle of 40° with the x-axis.

[0079] In this embodiment, the first magnet, the second magnet, the third magnet, and the fourth magnet can be neodymium iron boron magnets, with the grade N50 or N52, preferably N52.

[0080] The fastener has a receiving cavity for fixing the magnet. The fastener can be made of steel. The fastener is located in a second receiving space between the inner wall and the outer wall of the housing. The first magnet, second magnet, third magnet, and fourth magnet of the first magnetic unit 51 and the second magnetic unit 52 are respectively embedded in the fastener.

[0081] Most of the magnetic refrigeration bed assembly 6 is located within the first accommodating space between the shell and the stator 3. The magnetic refrigeration bed assembly 6 includes a first magnetic refrigeration bed 61, a second magnetic refrigeration bed 62, a third magnetic refrigeration bed 63, and a fourth magnetic refrigeration bed 64, all of which are fan-shaped and arranged in a ring. The interiors of the first magnetic refrigeration bed 61, the second magnetic refrigeration bed 62, the third magnetic refrigeration bed 63, and the fourth magnetic refrigeration bed 64 are all hollow structures to accommodate the magnetic working fluid; each end of these magnetic refrigeration beds has through holes for connecting heat exchange fluid pipelines. The magnetic refrigeration bed assembly 6 can dissipate the hot and cold heat generated by the magnetocaloric effect, thus achieving refrigeration. During operation, the magnetic refrigeration bed assembly 6 remains stationary.

[0082] There are two bearings 7. Each bearing 7 has a ring-shaped structure. The two bearings 7 are located at opposite ends of the housing, configured to allow the rotor 5 to rotate around the stator 3. The permanent magnet circuit device also includes bearing housings, with the bearings fitting into the housings.

[0083] There are two bases 2, arranged opposite each other. Base 2 has a circular ring structure. The stator 3 and shaft 1 are connected to base 2. The bearing housing is connected to the base. During operation, neither base 2 nor the bearing housing rotates.

[0084] The magnetic field distribution of the permanent magnet circuit device in this embodiment is as follows: Figure 5 As shown.

[0085] Example 2

[0086] This embodiment provides a rotary magnetic refrigerator, including the permanent magnet circuit device described in Embodiment 1.

[0087] This utility model is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this utility model fall within the scope of this utility model.

Claims

1. A permanent magnet circuit device, characterized in that, Includes shaft, stator, and rotor; The stator has a cylindrical structure and is sleeved on the outside of the shaft. The inner wall of the stator is fixed to the outer wall of the shaft. The two ends of the shaft are located outside the two ends of the stator, respectively. The rotor includes a housing, a first magnetic unit, and a second magnetic unit; the housing has a cylindrical structure. The housing is fitted onto the outside of the stator, with a first accommodating space between them; the housing has an inner sidewall and an outer sidewall, with a second accommodating space between the inner sidewall and the outer sidewall for accommodating the first magnetic unit and the second magnetic unit. Based on the number, shape, and size of the magnets, the first magnetic unit and the second magnetic unit are symmetrically arranged about the center line of the axis. The first magnetic unit includes n layers of magnets distributed radially along the shell, and the second magnetic unit includes n layers of magnets distributed radially along the shell, where n is a positive integer greater than or equal to 2. The n layers of magnets include a first layer of magnets and a second layer of magnets. The first layer of magnets includes m first magnets of the same shape and size. These first magnets are all fan-shaped and are arranged in sequence along the perimeter of the shell, close to the inner wall of the shell, and m is an even number greater than or equal to 6. The second layer of magnets includes (m-2) second magnets of the same shape and size. These second magnets are all fan-shaped and are arranged sequentially along the perimeter of the shell, close to the side of the first layer of magnets away from the inner wall of the shell. The two first magnets at both ends of the first layer of magnets are not provided with second magnets on the side away from the inner wall of the shell.

2. The permanent magnet circuit device according to claim 1, characterized in that, n is a positive integer greater than or equal to 3; the n-layer magnet group also includes a third layer magnet group; The third magnet group includes (m-4) third magnets of the same shape and size. These third magnets are all fan-shaped and are arranged sequentially along the perimeter of the shell, close to the side of the second magnet group away from the inner wall of the shell. No third magnets are arranged on the side of the two second magnets at both ends of the second magnet group away from the inner wall of the shell.

3. The permanent magnet circuit device according to claim 2, characterized in that, n is 4 and m is 8.

4. The permanent magnet circuit device according to claim 1, characterized in that: The first magnetic unit is configured as a plurality of units, which are stacked along the central axis of the housing; The second magnetic unit is configured as a plurality of units, which are stacked along the central axis of the housing.

5. The permanent magnet circuit device according to claim 4, characterized in that, The first magnetic unit is set to three or more; the second magnetic unit is set to three or more; the number of the first magnetic unit and the number of the second magnetic unit are equal.

6. The permanent magnet circuit device according to claim 2, characterized in that, The rotor also includes a fixing member with a receiving cavity, the fixing member being located within the second receiving space; the first magnet, the second magnet, and the third magnet are all embedded within the fixing member.

7. The permanent magnet circuit device according to claim 1, characterized in that, It also includes a magnetic refrigeration bed assembly, which comprises multiple magnetic refrigeration beds, all of which are fan-shaped and arranged in a ring, and located in a first accommodating space between the shell and the stator; the interior of each of the multiple magnetic refrigeration beds is configured as a hollow structure to accommodate the magnetic working fluid; and through holes are provided at both ends of each of the magnetic refrigeration beds for connecting heat exchange fluid pipelines.

8. The permanent magnet circuit device according to claim 1, characterized in that, It also includes two bearings; the bearings are in the form of a ring; the two bearings are located at the two ends of the housing respectively, and are configured to allow the rotor to rotate around the stator.

9. The permanent magnet circuit device according to claim 8, characterized in that, It also includes two opposing bases; the bases are in the form of a ring; the two bases are respectively connected to the two ends of the stator and the shaft.

10. A rotary magnetic refrigeration machine, characterized in that, Includes the permanent magnet circuit device as described in any one of claims 1 to 9.

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