Electronic expansion valve and magnetization method

Abstract

The present invention relates to an electronic expansion valve (1000) and a magnetization method. The electronic expansion valve (1000) includes a valve body (300), a spindle assembly (400), a rotor assembly (200), and a stator assembly (100). The valve body (300) includes a valve chamber (310) and a valve port (320). At least a portion of the spindle assembly (400) is provided in the valve chamber (310). The stator assembly (100) is provided outside the rotor assembly (200). The rotor assembly (200) includes a connecting member (210) and a Halbach pole array structure (220). The rotor assembly (200) is connected to the spindle assembly (400) by the connecting member (210), and the Halbach pole array structure (220) is fixed in an annular manner around the outer circumference of the connecting member (210).

Description

Technical Field

[0001] (Related Application) This application claims the priority of a Chinese patent application with an application number of 202310618856.4 and a title of "Electronic Expansion Valve and Magnetization Method", which was filed on May 29, 2023, and the full text of which is incorporated herein by reference.

[0002] This application relates to the technical field of motors, and particularly to electronic expansion valves and magnetization methods.

Background Art

[0003] Generally, a motor is an actuator that converts a pulse signal into an angular displacement. When the driver receives one pulse signal, the driver drives the motor to rotate by one fixed angle (i.e., the step angle) in a set direction. Therefore, by controlling the number of pulses, the angular displacement amount of the motor can be controlled to achieve the purpose of accurate positioning, and by controlling the frequency of the pulses, the rotation speed and acceleration of the motor can be controlled to achieve the purpose of motor speed regulation.

[0004] Furthermore, an electronic expansion valve uses a pulse motor to directly drive a needle valve to open and close the valve port. When the pulse voltage of the control circuit acts on the coils of each phase of the stator of the motor according to a certain logical relationship, the rotor of the motor made of a permanent magnet receives the action of the magnetic moment and generates a rotational motion. When the energization sequence of the stator of the motor changes, the rotation direction of the rotor also changes accordingly. Therefore, the electromagnetic torque generated by the motor is extremely important for the opening and closing of the electronic expansion valve.

[0005] In related technologies, the magnetization method for motor rotors is periodic N / S radial magnetization, where N represents the North Magnetic Pole and S represents the South Magnetic Pole. Furthermore, this magnetization method does not result in a large difference between the internal and external magnetic field distributions of the motor rotor. The stator of the electronic expansion valve motor is located outside the rotor, and the influence of the internal magnetic field of the motor rotor on the motor's performance is small. In other words, the magnetization method for motor rotors in related technologies easily reduces the utilization rate of permanent magnet materials. [Overview of the project]

[0006] According to various embodiments of this application, an electronic expansion valve and a magnetization method are provided.

[0007] The electronic expansion valve provided in this application comprises a valve body, a spindle assembly, a rotor assembly, and a stator assembly, the valve body having a valve chamber and a valve port communicating with the valve chamber, the spindle assembly being at least partially located within the valve chamber, the rotor assembly being connected to the spindle assembly, and the stator assembly being located outside the rotor assembly, so that the rotor assembly can move the spindle assembly toward or toward the valve port to control the opening of the valve port. The rotor assembly comprises a connecting member and a Halbach pole array structure, the rotor assembly being connected to the spindle assembly by the connecting member, and the Halbach pole array structure being fixed in an annular manner around the outer circumference of the connecting member so that the magnetic flux density on the side of the rotor assembly farther from the connecting member is greater than the magnetic flux density on the side of the rotor assembly closer to the connecting member.

[0008] In one embodiment, the Halbach pole array structure includes a plurality of pole modules, and the plurality of pole modules are arranged to form a ring-shaped Halbach pole array structure.

[0009] In one embodiment, the Halbach pole array structure includes a plurality of constituent units periodically arranged along its circumferential direction. Each constituent unit includes six pole modules, which are respectively defined as a first pole, a second pole, a third pole, a fourth pole, a fifth pole, and a sixth pole arranged in a clockwise direction. The magnetization direction of the second pole points in the direction of the center of the Halbach pole array structure along the radial direction of the Halbach pole array structure. The magnetization direction of the first pole is deflected counterclockwise by a preset angle a from the magnetization direction of the second pole. The magnetization direction of the third pole is deflected clockwise by a preset angle a from the magnetization direction of the second pole. The magnetization direction of the fifth pole is in the direction away from the center of the Halbach pole array structure along the radial direction of the Halbach pole array structure. The magnetization direction of the fourth pole is deflected counterclockwise by a preset angle a from the magnetization direction of the fifth pole. The magnetization direction of the sixth pole is deflected clockwise by a preset angle a from the magnetization direction of the fifth pole. Also, the preset angle a satisfies 0° < a < 90°.

[0010] In one embodiment, the preset angle a satisfies 10° ≤ a ≤ 60°.

[0011] In one embodiment, the preset angle a is equal to 30°.

[0012] In one embodiment, the connecting member is provided with an annular slot surrounding its axial direction. The opening of the annular slot is provided on the outer peripheral side of the connecting member. The pole module includes a locking head and a body portion. The locking head is connected to one end of the body portion close to the connecting member. And the pole module can be locked and provided in the annular slot along the radial direction of the connecting member by the locking head.

[0013] In one embodiment, the rotor assembly further includes a sleeve, which is fitted on the side of the body portion far from the locking head so that a plurality of pole modules are fixedly sandwiched between the sleeve and the connecting member.

[0014] In one embodiment, the locking head and the body portion are of an integrally formed structure.

[0015] This application further provides a magnetization method, which first includes the steps of magnetizing a plurality of magnetic pole modules, fixing the magnetized magnetic pole modules outside the connecting member to form an annular Halbach magnetic pole array structure, and then fitting a sleeve outside the Halbach magnetic pole array structure so that the Halbach magnetic pole array structure is fixedly sandwiched between the connecting member and the sleeve.

[0016] In one embodiment, the Halbach magnetic pole array structure is divided into a plurality of constituent units periodically arranged along its circumferential direction. Each constituent unit includes six magnetic pole modules, which are respectively defined as the first magnetic pole, the second magnetic pole, the third magnetic pole, the fourth magnetic pole, the fifth magnetic pole, and the sixth magnetic pole arranged in a clockwise direction. The magnetization method of the magnetic pole modules within each constituent unit is to magnetize the second magnetic pole in the direction pointing towards the center of the Halbach magnetic pole array structure along the radial direction of the Halbach magnetic pole array structure, magnetize the first magnetic pole along the direction deflected counterclockwise by a preset angle a along the magnetization direction of the second magnetic pole, magnetize the third magnetic pole along the direction deflected clockwise by a preset angle a along the magnetization direction of the second magnetic pole, magnetize the fifth magnetic pole in the direction away from the center of the Halbach magnetic pole array structure along the radial direction of the Halbach magnetic pole array structure, magnetize the fourth magnetic pole along the direction deflected counterclockwise by a preset angle a along the magnetization direction of the fifth magnetic pole, and magnetize the sixth magnetic pole along the direction deflected clockwise by a preset angle a along the magnetization direction of the fifth magnetic pole, and the preset angle a satisfies 0° < a < 90°.

[0017] Details of one or more embodiments of this application are presented in the following drawings and descriptions. Other features, objectives, and advantages of this application will become apparent from the specification, drawings, and claims.

Brief Description of the Drawings

[0018] To better describe and explain the embodiments and / or examples of these inventions disclosed herein, one or more drawings can be referred to. The additional details or examples used to explain the drawings should not be regarded as limiting the scope of any of the disclosed inventions, the embodiments and / or examples described herein, and the optimal forms of these inventions understood herein.

[0019] [Figure 1] It is a schematic diagram of the magnetization method of the magnetic pole array in the related art. [Figure 2] It is a distribution diagram of the effective magnetic flux density of the air gap outside the rotor of the motor with the magnetic pole array in the related art. [Figure 3] It is a distribution diagram of the effective magnetic flux density of the air gap inside the rotor of the motor with the magnetic pole array in the related art. [Figure 4] It is a distribution diagram of the ineffective magnetic flux density of the air gap outside the rotor of the motor with the magnetic pole array in the related art. [Figure 5] It is a harmonic distribution diagram of the magnetic pole array in the related art. [Figure 6] It is a schematic diagram of the electronic expansion valve provided by this application. [Figure 7] It is a schematic diagram of the assembled structure of the stator assembly and the rotor assembly of an embodiment provided by this application. [Figure 8] It is a cross-sectional view of the assembled structure of the stator assembly and the rotor assembly in FIG. 7. [Figure 9] It is a schematic structural diagram of the rotor assembly of an embodiment provided by this application. [Figure 10] It is a cross-sectional view of the rotor assembly in FIG. 9. [Figure 11] It is a schematic diagram of the magnetization method of the rotor assembly of an embodiment provided by this application. [Figure 12] It is a schematic structural diagram of the magnetic pole module of an embodiment provided by this application. [Figure 13] It is a schematic structural diagram of the connecting member of an embodiment provided by this application. [Figure 14] It is a distribution diagram of the effective magnetic flux density of the air gap outside the rotor assembly of an embodiment provided by the present application. [Figure 15] It is a distribution diagram of the effective magnetic flux density of the air gap inside the rotor assembly of an embodiment provided by the present application. [Figure 16] It is a distribution diagram of the ineffective magnetic flux density of the air gap outside the rotor assembly of an embodiment provided by the present application. [Figure 17] It is a harmonic distribution diagram of the rotor assembly of an embodiment provided by the present application.

[0020] 1000 Electronic expansion valve, 100 Stator assembly, 200 Rotor assembly, 210 Connecting member, 211 Annular slot, 220 Halbach magnetic pole array structure, 221 Constituent unit, 222 Magnetic pole module, 2221 Locking head, 2222 Body part, 223 First magnetic pole, 224 Second magnetic pole, 225 Third magnetic pole, 226 Fourth magnetic pole, 227 Fifth magnetic pole, 228 Sixth magnetic pole, 230 Sleeve, 231 Flange structure, 300 Valve body, 310 Valve chamber, 320 Valve port, 400 Spindle assembly.

Embodiments for Carrying out the Invention

[0021] In the description of the present application, terms such as "center", "vertical direction", "horizontal direction", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial direction", "radial direction", "circumferential direction", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for facilitating the description of the present application and simplifying the description, and do not indicate or imply that the shown device or element must have a specific orientation and must be configured and operated in a specific orientation. Therefore, it should be understood that the present application should not be construed as limiting.

[0022] Furthermore, the terms “first” and “second” are for descriptive purposes only and should not be understood as indicating or implying relative importance, or implicitly specifying the number of technical features described. Thus, features limited by “first” and “second” may either explicitly or implicitly include at least one of those features. In the description of this application, “multiple” means at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited.

[0023] In this application, unless otherwise explicitly stated and limited, terms such as “attached,” “connected,” “connected,” and “fixed” should be interpreted in a broad sense, for example, they may be fixedly connected, detachably connected, integrated, mechanically connected, electrically connected, directly connected to each other, indirectly connected to each other via an intermediate medium, or be internal communication between two elements or an interaction relationship between two elements. A person skilled in the art will be able to understand the specific meaning of the above terms in this application, depending on the specific circumstances.

[0024] In this application, unless otherwise explicitly stated or limited, the presence of a first feature "above" or "below" a second feature may mean that the first and second features are in direct contact, or that they are indirectly in contact through an intermediate medium. Furthermore, the presence of a first feature "above," "above," and "upper side" of a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply that the horizontal height of the first feature is higher than that of the second feature. The presence of a first feature "below," "below," and "below side" of a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply that the horizontal height of the first feature is lower than that of the second feature.

[0025] It should be explained that when an element is said to be "fixed" or "attached" to another element, it may be directly on the other element, or there may be an intervening element. When one element is said to be "connected" to another element, it may be directly connected to the other element, or there may be an intervening element simultaneously. The terms “vertical,” “horizontal,” “up,” “down,” “left,” and “right,” and similar expressions used in this text, are for illustrative purposes only and do not indicate that they represent only one embodiment.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art relating to this application. In the text, terms used in the specification of this application are for the sole purpose of describing specific embodiments and are not intended to limit this application. The terms “and / or” used herein include any and all combinations of the items relating to them, one or more.

[0027] Typically, a motor is an actuator that converts pulse signals into angular displacement. When a driver receives a single pulse signal, it drives the motor to rotate it by a fixed angle (i.e., a step angle) in a set direction. Therefore, by controlling the number of pulses, the amount of angular displacement of the motor can be controlled to achieve precise positioning, and by controlling the pulse frequency, the rotational speed and acceleration of the motor can be controlled to achieve speed adjustment.

[0028] Furthermore, the electronic expansion valve uses a pulse motor to directly drive the needle valve, opening and closing the valve opening. When the pulse voltage of the control circuit acts on the coils of each phase of the motor's stator according to a certain logical relationship, the motor rotor, made of permanent magnets, generates rotational motion due to the action of magnetic moments. When the energization sequence of the motor's stator changes, the direction of rotation of the rotor also changes accordingly. Therefore, the electromagnetic torque generated by the motor is extremely important for opening and closing the electronic expansion valve.

[0029] As shown in Figures 1 to 3, the magnetization method for the motor rotor in the related technology is periodic N / S radial magnetization, where N represents the North Magnetic Pole and S represents the South Magnetic Pole. Furthermore, with the above magnetization method, there is no significant difference in the distribution of the internal and external magnetic fields of the motor rotor. The stator of the electronic expansion valve motor is located outside the rotor, and the influence of the internal magnetic field of the motor rotor on the motor's performance is small. In other words, the magnetization method for the motor rotor in the related technology easily reduces the utilization rate of permanent magnet material.

[0030] Referring to Figures 6 to 17, in order to solve the problem in related technologies where the utilization rate of permanent magnet material is reduced due to the magnetization method of the motor rotor, this application provides an electronic expansion valve 1000 and a magnetization method. The electronic expansion valve 1000 includes a valve body 300 (not shown), a spindle assembly 400 (not shown), a rotor assembly 200, and a stator assembly 100. The valve body 300 is provided with a valve chamber 310 (not shown) and a valve port 320 (not shown) communicating with the valve chamber 310. The spindle assembly 400 is at least partially located within the valve chamber 310, the rotor assembly 200 is connected to the spindle assembly 400, and the stator assembly 100 is located outside the rotor assembly 200.

[0031] The rotor assembly 200 includes a connecting member 210 and a Halbach pole array structure 220, the rotor assembly 200 being connected to the spindle assembly 400 by the connecting member 210, and the Halbach pole array structure 220 being fixed in an annular manner around the outer circumference of the connecting member 210 so that the magnetic flux density on the side of the rotor assembly 200 farther from the connecting member 210 is greater than the magnetic flux density on the side of the rotor assembly 200 closer to the connecting member 210.

[0032] It should be explained that the Halbach pole array structure 220 is a special pole array structure that enhances the magnetic flux density in a specific direction by arranging and combining magnet units.

[0033] In this embodiment, the Halbach pole array structure 220 controls the directional magnetization of the rotor assembly 200 so that the magnetic flux density on the side of the rotor assembly 200 far from the connecting member 210 is greater than the magnetic flux density on the side of the rotor assembly 200 close to the connecting member 210. Furthermore, since the stator assembly 100 is provided outside the rotor assembly 200, that is, the stator assembly 100 is provided on the side far from the connecting member 210 of the Halbach pole array structure 220, the magnetic flux density on the side of the rotor assembly 200 close to the stator assembly 100 is greater than the magnetic flux density on the side of the rotor assembly 200 far from the stator assembly 100, and furthermore, the magnetic field utilization rate of the rotor assembly 200 is effectively improved.

[0034] Furthermore, in one embodiment, as shown in Figure 9, the Halbach pole array structure 220 includes a plurality of pole modules 222, and the plurality of pole modules 222 are formed in a circular arrangement on the Halbach pole array structure 220.

[0035] This configuration effectively reduces the difficulty of machining the Halbach pole array structure 220 and further reduces the manufacturing cost of the electronic expansion valve 1000.

[0036] Furthermore, the Halbach pole array structure 220 is uniformly divided along its circumferential direction to form multiple pole modules 222.

[0037] Furthermore, in one embodiment, as shown in Figures 9 to 13, the connecting member 210 is provided with an annular slot 211 surrounding its axial direction, the opening of the annular slot 211 is provided on the outer circumference side of the connecting member 210, and the magnetic pole module 222 includes a locking head 2221 and a main body 2222, the locking head 2221 is connected to one end of the main body 2222 closer to the connecting member 210, and the magnetic pole module 222 may be provided locked in the annular slot 211 along the radial direction of the connecting member 210 by a locking portion. The rotor assembly 200 further includes a sleeve 230, the sleeve 230 is fitted to the side of the main body 2222 farther from the locking head 2221, and a plurality of magnetic pole modules 222 are fixedly sandwiched between the sleeve 230 and the connecting member 210.

[0038] It should be noted that both the sleeve 230 and the connecting member 210 are made of non-permeable materials. Specifically, the materials of the sleeve 230 and the connecting member 210 may be metals and alloys other than iron-cobalt-nickel and its alloys, such as gold, silver, copper, aluminum, zinc, titanium, nickel, molybdenum, chromium, and cobalt.

[0039] With this configuration, when assembling the rotor assembly 200, the multiple pole modules 222 may first be locked in the annular slot 211 along the radial direction of the connecting member 210 by the locking head 2221, in which case the annular slot 211 can prevent the pole modules 222 from moving along the axial direction of the connecting member 210. Then, the sleeve 230 is fitted to the side of the main body 2222 that is farther from the locking head 2221, in which case the sleeve 230 can prevent the pole modules 222 from moving along the radial direction of the connecting member 210, thereby completing the assembly of the rotor assembly 200. In other words, the above assembly method can firmly hold the multiple pole modules 222 between the sleeve 230 and the connecting member 210 by simultaneously restricting the axial and radial movement of the pole modules 222 along the connecting member 210.

[0040] Naturally, the above assembly method also allows for easy disassembly. Specifically, by first removing the sleeve 230 from the outside of the Halbach pole array structure 220, the multiple pole modules 222 can be removed in sequence.

[0041] Therefore, this configuration significantly reduces the difficulty of assembling and disassembling the rotor assembly 200, and improves the rigidity of the rotor assembly 200.

[0042] In one embodiment, to prevent adjacent pole modules 222 from repelling each other and making assembly of the Halbach pole array structure 220 difficult, the pole modules 222 are bonded to the connecting member 210.

[0043] In one embodiment, the locking head 2221 and the main body 2222 are integrally molded.

[0044] Specifically, in one embodiment, the locking head 2221 is provided at one end of the main body 2222 that is farther from the spindle assembly 400, and one end of the main body 2222 is connected to the locking head 2221, while the other end extends in a direction closer to the spindle assembly 400, forming an elongated structure.

[0045] More specifically, in one embodiment, the connecting member 210 is in the shape of a rotating body, and the annular slot 211 is flared along the radial direction of the connecting member 210 and from one end closer to the axis of the connecting member 210 to the other end further from the axis.

[0046] This reduces the difficulty of assembling the locking head 2221 and the annular slot 211.

[0047] However, the invention is not limited to this, and in other embodiments, the connecting member 210 may be in the shape of a plate.

[0048] In one embodiment, a stepped structure (not shown) is provided on the inner wall of the annular slot 211 so that the inner wall of the annular slot 211 can be stopped along the radial direction of the connecting member 210 at one end of the locking head 2221 that is close to the axis of the connecting member 210.

[0049] In one embodiment, as shown in Figures 9 and 10, a flange structure 231 is provided at one end of the sleeve 230 furthest from the spindle assembly 400. One end of the flange structure 231 is connected to the edge of the sleeve 230, and the other end extends along the axis of the sleeve 230 and terminates at the end of the Halbach pole array structure 220 furthest from the spindle assembly 400.

[0050] This prevents the sleeve 230 from being displaced axially relative to the Halbach pole array structure 220, thereby improving the assembly rigidity of the rotor assembly 200.

[0051] As shown in Figures 4 and 5, the magnetization method of the motor rotor in the related technology results in a large reactive magnetic flux density in the air gap outside the motor rotor, i.e., a large amount of leakage magnetic flux, and a high content of harmonics (usually referring to odd harmonics) in the magnetic field at the air gap of the motor rotor. On the other hand, an increase in harmonics increases the copper and iron losses of the motor, which in turn increases the heat generated by the motor and causes an unnecessary temperature rise. Furthermore, an increase in the harmonic content leads to a larger torque pulse in the motor, causing significant vibration and noise. Moreover, an increase in the harmonic content adversely affects the insulation of the motor, which in turn causes the breakdown of the motor's insulation layer.

[0052] In order to solve the problems that there is a large amount of leakage magnetic flux in the rotor of the motor and the harmonic content of the magnetic field in the air gap outside the rotor of the motor is high, in one embodiment, as shown in FIG. 11, the Halbach pole array structure 220 includes a plurality of constituent units 221 periodically arranged along its circumferential direction, and each constituent unit 221 includes six pole modules 222, each of which is defined as a first pole 223, a second pole 224, a third pole 225, a fourth pole 226, a fifth pole 227, and a sixth pole 228 arranged in the clockwise direction. The magnetization direction of the second pole 224 points in the direction of the center of the Halbach pole array structure 220 along the radial direction of the Halbach pole array structure 220, the magnetization direction of the first pole 223 is deflected counterclockwise from the magnetization direction of the second pole 224 by a preset angle a, and the magnetization direction of the third pole 225 is deflected clockwise from the magnetization direction of the second pole 224 by a preset angle a. The magnetization direction of the fifth pole 227 is a direction away from the center of the Halbach pole array structure 220 along the radial direction of the Halbach pole array structure 220, the magnetization direction of the fourth pole 226 is deflected counterclockwise from the magnetization direction of the fifth pole 227 by a preset angle a, and the magnetization direction of the sixth pole 228 is deflected clockwise from the magnetization direction of the fifth pole 227 by a preset angle a. Also, the preset angle a satisfies 0° < a < 90°.

[0053] Specifically, in one embodiment, the Halbach pole array structure 220 includes six constituent units 221, and the six constituent units 221 are periodically arranged and connected in sequence along the circumferential direction of the Halbach pole array structure 220.

[0054] However, it is not limited thereto, and in other embodiments, the number of the constituent units 221 may be other values, which will not be listed one by one here.

[0055] It should be noted that the preset angle a is any value between 0 and 90° (excluding 0° and 90°), that is, a may be 5°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80° or 85°, etc., which will not be listed one by one here.

[0056] Preferably, the preset angle a satisfies 10° ≤ a ≤ 60°.

[0057] Furthermore, when the preset angle a takes the same value as 30°, the effective magnetic flux density of the Halbach pole array structure 220 of this application and the effective magnetic flux density of pole arrays in related art are compared and analyzed, and referring to Figures 2 and 14, a comparison table of the effective magnetic flux density of the outer air gap of the rotor assembly 200 is obtained as shown in Table 1, and referring to Figures 3 and 15, a comparison table of the effective magnetic flux density of the inner air gap of the rotor assembly 200 is obtained as shown in Table 2.

[0058] It should be explained that in Figures 2, 3, 14, and 15, the horizontal axis, Degree, indicates the angular position along the circumferential direction of the motor rotor (or rotor assembly 200), so the maximum value on the horizontal axis is 360°, which is exactly one full rotation. In Figures 2, 3, 14, and 15, the vertical axis, Br, represents magnetic flux density, and the unit is T (Tesla).

[0059] [Table 1]

[0060] [Table 2]

[0061] It should be explained that "the outer air gap of the rotor assembly 200" refers to the magnetic flux density on the side of the rotor assembly 200 closer to the stator assembly 100, "the inner air gap of the rotor assembly 200" refers to the magnetic flux density on the side of the Halbach pole array structure 220 (or pole array) closer to the connecting member 210, and "effective magnetic flux density" refers to the magnetic flux density along the radial direction of the connecting member 210, that is, the magnetic flux density perpendicular to the current direction.

[0062] Table 1 shows that, regarding the magnetic flux density of the air gap outside the rotor assembly 200, the effective value of the magnetic flux density of the Halbach pole array structure 220 of this application is significantly larger than the effective value of the magnetic flux density of pole arrays in related technologies, and the maximum value of the magnetic flux density of the Halbach pole array structure 220 of this application is also significantly larger than the maximum value of the magnetic flux density of pole arrays in related technologies. Specifically, the effective value of the magnetic flux density of the air gap outside the rotor assembly 200 improved by 34.7%, and the maximum value of the magnetic flux density of the air gap outside the rotor assembly 200 improved by 80.3%.

[0063] Table 2 shows that, regarding the magnetic flux density of the air gap inside the rotor assembly 200, the effective value of the magnetic flux density of the Halbach pole array structure 220 of this application is significantly smaller than the effective value of the magnetic flux density of pole arrays in related technologies, and the maximum value of the magnetic flux density of the Halbach pole array structure 220 of this application is also significantly smaller than the maximum value of the magnetic flux density of pole arrays in related technologies. Specifically, the effective value of the magnetic flux density of the air gap inside the rotor assembly 200 decreased by 60%, and the maximum value of the magnetic flux density of the air gap inside the rotor assembly 200 decreased by 28.5%.

[0064] From the above, it can be seen that with this configuration, the magnetic flux density in the outer air gap of the rotor assembly 200 increases significantly, and the magnetic flux density in the inner air gap of the rotor assembly 200 decreases, thereby improving the utilization rate of the magnetic performance of the magnetic material of the rotor assembly 200.

[0065] Furthermore, as the magnetic flux density of the air gap outside the rotor assembly 200 increases, the air gap outside the rotor assembly 200 can also generate a larger electromagnetic torque, which increases the rotational acceleration of the rotor assembly 200, i.e., the rotational acceleration of the spindle assembly 400, and furthermore, increases the speed at which the electronic expansion valve 1000 opens the valve port 320 and closes the valve port 320.

[0066] Furthermore, as the electromagnetic torque generated in the air gap outside the rotor assembly 200 increases, the stroke that the spindle assembly 400 of the electronic expansion valve 1000 can move also increases significantly. This increase in the stroke of the electronic expansion valve 1000 allows for an increase in the flow rate of the refrigerant in the valve chamber 310, and furthermore, it can reduce the superheating of the electronic expansion valve 1000. At the same time, as the flow rate of the refrigerant increases, the pressure of the refrigerant at the outlet of the valve port 320 also increases. This prevents the refrigerant evaporation pressure from being too low and the refrigerant temperature from being too low, thereby accelerating the evaporation rate of the refrigerant and improving the amount of refrigerant cooled per unit volume per unit time. In other words, the cooling efficiency of the electronic expansion valve 1000 is improved.

[0067] When the preset angle a is equal to 30°, the reactive magnetic flux density of the Halbach pole array structure 220 of this application and the reactive magnetic flux density of pole arrays in related art are compared and analyzed, and a comparison table of the degree of leakage flux outside the rotor assembly 200 is obtained, as shown in Table 3, with reference to Figures 4 and 16.

[0068] [Table 3]

[0069] It should be explained that the "degree of leakage magnetic flux outside the rotor assembly 200" refers to the ineffective magnetic flux density of the air gap outside the rotor assembly 200, that is, the magnetic flux density along the circumferential direction of the connecting member 210, that is, the magnetic flux density parallel to the current direction. Since the magnetic field direction in this direction is parallel to the current direction, it cannot generate an electromagnetic force.

[0070] Furthermore, it should be explained that the horizontal axis Degree in Figures 4 and 16 indicates the angular position along the circumferential direction of the motor rotor (or rotor assembly 200), so the maximum value on the horizontal axis is 360°, which is exactly one full rotation. The vertical axis Br in Figures 4 and 16 represents magnetic flux density, and the unit is T (Tesla).

[0071] Table 3 shows that the average leakage flux density outside the rotor assembly 200 of the Halbach pole array structure 220 of this application is 0.0001T, which is only one-third of the leakage flux density generated by pole arrays in related art. As a result, the degree of leakage flux in the air gap outside the rotor assembly 200 is significantly reduced, and furthermore, the utilization efficiency of the Halbach pole array structure 220 is improved.

[0072] When the preset angle a is equal to 30°, the harmonic distribution of the Halbach pole array structure 220 of this application and the harmonic distribution of pole arrays in related technologies are compared and analyzed, and a comparison table of harmonic distributions as shown in Table 4 is obtained by referring to Figures 5 and 17.

[0073] [Table 4]

[0074] It should be explained that the fundamental wave is also called the first harmonic, and that is, the leftmost harmonic in Figures 5 and 17 has the largest amplitude. The larger the amplitude of the fundamental wave and the smaller the amplitudes of the other odd harmonics, the closer the waveform becomes to a sine wave, which reduces motor vibration.

[0075] Table 4 shows that the fundamental wave amplitude of the magnetic field in the outer air gap of the Halbach pole array structure 220 of this application is 0.6831, while the fundamental wave amplitude of the pole array in related technology is 0.4665. This indicates that the fundamental wave amplitude of the magnetic field in the outer air gap of the Halbach pole array structure 220 of this application is 46.4% higher than that of the pole array in related technology. Furthermore, the content of odd harmonics of each remaining order in the magnetic field of the outer air gap of the Halbach pole array structure 220 of this application shows an overall decreasing trend compared to the content of odd harmonics in the pole array in related technology. Specifically, compared to pole arrays in related technologies, the third, fifth, seventh, ninth, and eleventh harmonics of the magnetic field in the outer air gap of the Halbach pole array structure 220 of this application were reduced by 31.8%, 75%, -16%, 51.7%, and 82.2%, respectively.

[0076] Furthermore, theoretical calculations show that the harmonic distortion of the magnetic field in the outer air gap of the Halbach pole array structure 220 of this application is 0.216%, and the overall harmonic distortion of the magnetic field in the outer air gap of the Halbach pole array structure 220 of this application is reduced by 54.5% compared to pole arrays in related technologies.

[0077] Therefore, from the above, it can be seen that the Halbach pole array structure 220 of this application greatly improves the distribution of the magnetic field in the outer air gap by significantly improving the fundamental wave amplitude and effectively suppressing the content of remaining odd harmonics. Furthermore, the reduction in the content of remaining odd harmonics further reduces the copper and iron losses of the motor, reduces the amount of heat generated by the motor, and reduces unnecessary temperature rise of the motor. In addition, the reduction in the content of odd harmonics also reduces the torque pulse of the motor, thereby reducing the vibration and noise generated by the operation of the motor. Furthermore, the reduction in the content of odd harmonics can reduce the adverse effects on the insulation of the motor and prevent the destruction of the motor's insulating layer.

[0078] It should be noted that when the preset angle a takes other values (any value between 0 and 90°), similar experimental results and conclusions can be obtained as when it takes 30°, and they will not be listed one by one here.

[0079] This application First, a step of magnetizing a plurality of magnetic pole modules 222; A step of fixing the magnetized magnetic pole modules 222 to the outside of the connecting member 210 to form an annular Halbach magnetic pole array structure 220; Then, further provided is a magnetization method including a step of fitting a sleeve 230 outside the Halbach magnetic pole array structure 220 so that the Halbach magnetic pole array structure 220 is fixedly sandwiched between the connecting member 210 and the sleeve 230.

[0080] Furthermore, the Halbach magnetic pole array structure 220 is divided into a plurality of constituent units 221 periodically arranged along its circumferential direction. Each constituent unit 221 includes six magnetic pole modules 222, which are respectively defined as a first magnetic pole 223, a second magnetic pole 224, a third magnetic pole 225, a fourth magnetic pole 226, a fifth magnetic pole 227, and a sixth magnetic pole 228 arranged clockwise. The magnetization method of the magnetic pole modules within each constituent unit 221 is as follows. Magnetize the second magnetic pole 224 along the radial direction of the Halbach magnetic pole array structure 220 and pointing towards the center of the Halbach magnetic pole array structure 220. Magnetize the first magnetic pole 223 along a direction deflected counterclockwise by a preset angle a along the magnetization direction of the second magnetic pole 224. Magnetize the third magnetic pole 225 along a direction deflected clockwise by a preset angle a along the magnetization direction of the second magnetic pole 224. Magnetize the fifth magnetic pole 227 along a direction deviating from the center of the Halbach magnetic pole array structure 220 along the radial direction of the Halbach magnetic pole array structure 220. Magnetize the fourth magnetic pole 226 along a direction deflected counterclockwise by a preset angle a along the magnetization direction of the fifth magnetic pole 227. Magnetize the sixth magnetic pole 228 along a direction deflected clockwise by a preset angle a along the magnetization direction of the fifth magnetic pole 227. Also, the preset angle a satisfies 0° < a < 90°.

[0081] Furthermore, in order to reduce the difficulty of installing the magnetic pole modules 222, in one embodiment, the anisotropic magnetic pole module 222, which has already been magnetized, can first be fixed to the outside of the connecting member 210, and then the isotropic magnetic pole module 222 can be installed.

[0082] The technical features of the above embodiments can be combined in any way, and for the sake of simplicity, not all possible combinations of the technical features in the embodiments described above have been described. However, as long as these combinations of technical features are inconsistent, they should be considered to fall within the scope described herein.

[0083] The embodiments described above are merely examples of some embodiments of the present application, and although the descriptions are specific and detailed, they should not be understood as limiting the scope of the claims of the application. It should be noted that a person skilled in the art can make several further modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application shall be in accordance with the attached claims.

Claims

1. The system includes a valve body, a spindle assembly, a rotor assembly, and a stator assembly, wherein the valve body is provided with a valve chamber and a valve port communicating with the valve chamber, the spindle assembly is at least partially located within the valve chamber, the rotor assembly is connected to the spindle assembly, and the stator assembly is located outside the rotor assembly, so that the rotor assembly can move the spindle assembly toward or away from the valve port to control the opening of the valve port. An electronic expansion valve comprising a rotor assembly including a connecting member and a Halbach pole array structure, wherein the rotor assembly is connected to a spindle assembly by the connecting member, and the Halbach pole array structure is fixed in an annular manner on the outer circumference of the connecting member such that the magnetic flux density on the side of the rotor assembly far from the connecting member is greater than the magnetic flux density on the side of the rotor assembly close to the connecting member.

2. The electronic expansion valve according to claim 1, wherein the Halbach pole array structure includes a plurality of pole modules, and the plurality of pole modules are formed in a circular arrangement on the Halbach pole array structure.

3. The Halbach pole array structure comprises a plurality of constituent units arranged periodically along its circumferential direction, each constituent unit comprising six pole modules, each defined as a first pole, second pole, third pole, fourth pole, fifth pole, and sixth pole arranged clockwise. The magnetization direction of the second magnetic pole is directed toward the center of the Halbach magnetic pole array structure along the radial direction of the Halbach magnetic pole array structure, the magnetization direction of the first magnetic pole is deflected counterclockwise by a preset angle a from the magnetization direction of the second magnetic pole, and the magnetization direction of the third magnetic pole is deflected clockwise by a preset angle a from the magnetization direction of the second magnetic pole. The magnetization direction of the fifth magnetic pole is in the direction along the radial direction of the Halbach magnetic pole array structure, away from the center of the Halbach magnetic pole array structure; the magnetization direction of the fourth magnetic pole is deflected counterclockwise by a preset angle a from the magnetization direction of the fifth magnetic pole; and the magnetization direction of the sixth magnetic pole is deflected clockwise by a preset angle a from the magnetization direction of the fifth magnetic pole. Furthermore, the electronic expansion valve according to claim 2 satisfies that the preset angle a satisfies 0° < a < 90°.

4. The electronic expansion valve according to claim 3, wherein the preset angle a satisfies 10° ≤ a ≤ 60°.

5. The electronic expansion valve according to claim 3, wherein the preset angle a is equal to 30°.

6. The electronic expansion valve according to claim 2, wherein the connecting member is provided with an annular slot surrounding its axial direction, the opening of the annular slot is provided on the outer circumference side of the connecting member, the magnetic pole module includes a locking head and a main body, the locking head is connected to one end of the main body closest to the connecting member, and the magnetic pole module can be provided locked in the annular slot along the radial direction of the connecting member by the locking head.

7. The electronic expansion valve according to claim 6, wherein the rotor assembly further includes a sleeve, the sleeve being fitted to the side of the main body away from the locking head such that a plurality of the pole modules are fixedly sandwiched between the sleeve and the connecting member.

8. The electronic expansion valve according to claim 6, wherein the locking head and the main body are integrally molded.

9. First, there is the step of magnetizing multiple magnetic pole modules, The steps include fixing the magnetized magnetic pole module to the outside of the connecting member to form an annular Halbach magnetic pole array structure, A magnetization method comprising the step of subsequently fitting the sleeve to the outside of the Halbach pole array structure so that the Halbach pole array structure is fixedly sandwiched between the connecting member and the sleeve.

10. The Halbach pole array structure is divided into a plurality of constituent units arranged periodically along its circumferential direction, each constituent unit containing six pole modules, each defined as a first pole, second pole, third pole, fourth pole, fifth pole, and sixth pole arranged clockwise, and the magnetization method of the pole modules within each constituent unit is: The second magnetic pole is magnetized along the radial direction of the Halbach magnetic pole array structure, directed toward the center of the Halbach magnetic pole array structure, the first magnetic pole is magnetized in a direction deflected counterclockwise by a preset angle a along the magnetization direction of the second magnetic pole, and the third magnetic pole is magnetized in a direction deflected clockwise by the preset angle a along the magnetization direction of the second magnetic pole. The process involves magnetizing the fifth magnetic pole in a direction away from the center of the Halbach magnetic pole array structure along the radial direction of the Halbach magnetic pole array structure, magnetizing the fourth magnetic pole in a direction deflected counterclockwise by the preset angle a along the magnetization direction of the fifth magnetic pole, and magnetizing the sixth magnetic pole in a direction deflected clockwise by the preset angle a along the magnetization direction of the fifth magnetic pole. Furthermore, the magnetization method according to claim 9, wherein the preset angle a satisfies 0° < a < 90°.

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