Coil assembly and electronic expansion valve

Abstract

This application discloses a coil device and an electronic expansion valve, belonging to the field of flow control. The coil device includes an electromagnetic pole plate, a coil frame, and a stator winding. The stator winding is wound around the coil frame, and the electromagnetic pole plate is disposed on the outer periphery of the coil frame. The conductor of the stator winding is copper-clad aluminum or aluminum, the resistivity of the conductor is ρ, and the axial length of the stator winding is H; satisfying: 0.02251Ω•mm² / m≤ρ≤0.029Ω•mm 2 / m, 6.8mm≤H≤9mm. The above settings allow the electronic expansion valve, which includes a stator winding made of copper-clad aluminum wire, to achieve both high driving force and low cost.

Description

Technical Field

[0001] This application relates to the field of flow control, and more specifically, to a coil device and an electronic expansion valve for refrigeration / heating systems in the fields of air conditioners, heat pump water heaters, chillers, vending machines, ice makers, supermarket freezers, and refrigerators. Background Technology

[0002] In electronic expansion valves, the cost of the coil assembly made of copper stator windings accounts for a large proportion of the total cost of the electronic expansion valve.

[0003] Copper-clad aluminum conductors have become a potential alternative due to their good conductivity, lower cost, and lightweight advantages. However, since the resistivity of copper-clad aluminum conductors or aluminum conductors is greater than that of copper conductors, directly replacing copper conductors will lead to a decrease in the driving force of the electronic expansion valve due to the increased resistance.

[0004] To maintain a relatively constant driving force, the voltage can be adjusted to keep the current of the electronic expansion valve constant when the resistance increases, thus ensuring the driving force. However, this method requires a larger coil device to counteract the effect of increased resistance, which in turn increases the power consumption of the power supply and, according to Joule's law, also increases power loss.

[0005] Given this, we can try to keep the stator winding resistance, voltage, and current essentially constant, and the number of turns in the stator winding can also remain unchanged, only changing the conductor from copper to copper-clad aluminum. According to the stator winding resistance calculation formula R=ρL / S (ρ is resistivity, L is the wire length equivalent to the number of turns, and S is the conductor cross-sectional area equivalent to the wire diameter), we need to change the wire diameter and / or length, while also considering the amount of material used to ensure that the cost advantage brought by the change in materials is not offset by the increase in the amount of material used.

[0006] Therefore, how to keep the driving force of the electronic expansion valve consistent with that of a conventional copper wire electronic expansion valve while changing the conductor material of the stator winding at a lower cost is an urgent problem to be solved in the field of flow control. Utility Model Content

[0007] This application provides a coil device for an electronic expansion valve. The coil device includes an electromagnetic pole plate, a coil frame, and a stator winding. The stator winding is wound around the coil frame, and the electromagnetic pole plate is disposed on the outer periphery of the coil frame. The conductor of the stator winding is copper-clad aluminum or aluminum, the resistivity of the conductor is ρ, and the axial length of the stator winding is H, satisfying: 0.02251 Ω•mm. 2 / m≤ρ≤0.029Ω•mm 2 / m, 6.8mm≤H≤9mm.

[0008] The above technical solution has the following advantages: by controlling the resistivity of the conductor and the axial length of the stator winding within a reasonable range, the coil device of the stator winding made of copper-clad aluminum or aluminum conductors can have a higher driving force, while also having a significant cost advantage. That is, compared to copper conductors, the resistivity of copper-clad aluminum or aluminum conductors is slightly increased, and this arrangement helps to maintain a basically consistent driving force between the coil device of the stator winding made of copper-clad aluminum or aluminum conductors and the coil device of the stator winding made of copper conductors.

[0009] This application provides an electronic expansion valve, including a coil device, a rotor assembly, and a sleeve sleeved around the outer periphery of the rotor assembly. The coil device is sleeved around the outer periphery of the sleeve, and the rated voltage of the electronic expansion valve is 12V.

[0010] The above technical solution has the following advantages: by controlling the resistivity of the conductor and the axial length of the stator winding within a reasonable range, the electronic expansion valve using copper-clad aluminum or aluminum wire stator windings can achieve a lower minimum operating voltage. This means that the electronic expansion valve can drive the rotor assembly and open / close at a lower input voltage, resulting in higher operational stability. In other words, under the premise of the same rated voltage, electronic expansion valves with stator windings made of copper-clad aluminum or aluminum wires can maintain essentially the same minimum operating voltage as those with stator windings made of copper wires. Attached Figure Description

[0011] To more clearly illustrate the embodiments of this application, the embodiments will be described and explained in detail below with reference to the accompanying drawings.

[0012] Figure 1 This is a structural schematic diagram of a portion of the electronic expansion valve of this application;

[0013] Figure 2 This is a cross-sectional view of the coil device of this application;

[0014] Figure 3 This is a cross-sectional view of the wire in this application;

[0015] Figure 4 This is an isometric sectional view of the stator assembly of this application.

[0016] Icons: 100-Electronic expansion valve; 11-Stator assembly; 111-Stator winding; 112-Coil bobbin; 1121-First flange; 1122-Second flange; 1123-Cylinder body; 1131-First electromagnetic pole plate; 1131a-First claw pole; 1132a-Second claw pole; 1132-Second electromagnetic pole plate; 114-Encapsulation; 115-Pin; 20-Valve core assembly; 21-Sleeve; 22-Shaft assembly; 23-Rotor assembly; 24-Nut assembly; 25-Valve seat; 251-Valve port; 3-Wire; 31-Aluminum core; 32-Copper layer; 33-Insulating varnish film; 4-First channel; 5-Second channel. Detailed Implementation

[0017] To make this application clearer, specific embodiments are described below with reference to the accompanying drawings:

[0018] Please refer to Figures 1-4 This application provides a coil device for an electronic expansion valve 100. The coil device includes an electromagnetic pole plate, a coil frame 112, and a stator winding 111. The stator winding 111 is wound around the coil frame 112, and the electromagnetic pole plate is disposed on the outer periphery of the coil frame 112. The conductor 3 of the stator winding 111 is made of copper-clad aluminum, the resistivity of the conductor 3 is ρ, and the axial length of the stator winding 111 is H, satisfying: 0.02251 Ω•mm. 2 / m≤ρ≤0.029Ω•mm 2 / m, 6.8mm≤H≤9mm.

[0019] The resistivity of wire 3 can be 0.02251 Ω•mm. 2 / m, 0.023Ω•mm 2 / m, 0.0235Ω•mm 2 / m, 0.024Ω•mm 2 / m, 0.0245Ω•mm 2 / m, 0.025Ω•mm 2 / m, 0.0255Ω•mm 2 / m, 0.026Ω•mm 2 / m, 0.0265Ω•mm 2 / m, 0.027Ω•mm 2 / m, 0.0275Ω•mm 2 / m, 0.028Ω•mm 2 / m, 0.0285Ω•mm 2 / m, 0.029Ω•mm 2 The point value of any one of / m or the point value between any two of them.

[0020] The axial length of the stator winding 111 can be any one of 6.8mm, 6.9mm, 7mm, 7.1mm, 7.2mm, 7.3mm, 7.4mm, 7.5mm, 7.6mm, 7.7mm, 7.8mm, 7.9mm, 8mm, 8.1mm, 8.2mm, 8.3mm, 8.4mm, 8.5mm, 8.6mm, 8.7mm, 8.8mm, 8.9mm, or 9mm, or a value between any two of them.

[0021] According to the Ampere force formula F=BILsinθ (F: Ampere force, B: magnetic induction intensity, I: current intensity in conductor 3, L: effective length of rotor in magnetic field, θ: angle between current direction and magnetic field direction; it should be noted that the effective length L of rotor in magnetic field can be characterized by the axial length H of stator winding 111), the larger H is, the larger F is, and the greater the driving force.

[0022] The driving force of the coil device is also related to the current in conductor 3 and the number of turns in stator winding 111. The greater the current in conductor 3, the greater the driving force; the greater the number of turns in stator winding 111, the greater the driving force. According to the formula for calculating the resistance of stator winding 111, R=ρL / S (ρ is resistivity, L is the wire length equivalent to the number of turns, and S is the cross-sectional area of ​​conductor 3 equivalent to the wire diameter), combined with Ohm's law I=U / R (U is the input voltage of stator winding 111), it can be seen that the smaller ρ is, the smaller R is, the larger I is, and the greater the driving force. That is, with ρ constant, the larger H is, the greater the driving force; with H constant, the smaller ρ is, the greater the driving force.

[0023] Taking copper-clad aluminum conductor 3 as an example, the larger the ρ, the greater the proportion of aluminum core 31, and the lower the cost.

[0024] Taking aluminum conductor 3 as an example, the larger the ρ, the lower the cost.

[0025] The larger the value of H, the more materials are needed, resulting in higher costs.

[0026] In this embodiment, when H ≥ 6.8 mm and ρ ≤ 0.029 Ω•mm 2 When ρ ≥ 0.02251 Ω•mm, the coil device can have a large driving force. 2 When Ω / m and H≤9mm, the coil assembly has a lower cost. Therefore, when 0.02251Ω•mm 2 / m≤ρ≤0.029Ω•mm 2 When the diameter is 6.8mm ≤ H ≤ 9mm, the coil device can balance high driving force and low cost.

[0027] Please refer to Figures 1-4 , 7.2mm≤H≤9mm.

[0028] In this embodiment, when H≥7.2mm, the coil device can have a greater driving force, and when H≤9mm, the coil device can have a lower cost. Therefore, when 7.2mm≤H≤9mm, the coil device can achieve both higher driving force and lower cost.

[0029] Please refer to Figures 1-4 The conductor 3 of the stator winding 111 is made of copper-clad aluminum, and the copper content of conductor 3 is C, which satisfies: 15%≤C≤40%.

[0030] The copper content in conductor 3 can be any one of the following values ​​or any combination of two: 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, and 40%.

[0031] It should be noted that copper has better electrical conductivity than aluminum, higher cost, higher quality, and lower resistivity ρ.

[0032] As mentioned above, if H remains constant, the smaller ρ is, the greater the driving force.

[0033] In this embodiment, when C ≥ 15%, the copper content in wire 3 is high, resulting in better conductivity and higher driving force of the coil device. When C ≤ 40%, the copper content in wire 3 is low, leading to lower cost and lighter weight. Therefore, when 15% ≤ C ≤ 40%, wire 3 can achieve both good conductivity and light weight, while the coil device can achieve a balance between high driving force, light weight, and low cost.

[0034] Please refer to Figures 1-4 The number of turns of stator winding 111 is N, which satisfies: 470≤N≤550.

[0035] It should be noted that the number of turns of stator winding 111 is the total number of turns after stator winding 111 is completed.

[0036] The number of turns of stator winding 111 can be any one of the following values ​​or any combination of two values: 470, 472, 474, 476, 478, 480, 482, 484, 486, 488, 490, 492, 494, 496, 498, 500, 502, 504, 506, 508, 510, 512, 514, 516, 518, 520, 522, 524, 526, 528, 530, 532, 534, 536, 538, 540, 542, 544, 546, 548, and 550.

[0037] From the magnetic induction intensity B = μNI / l (μ is the permeability, N is the number of turns of the coil, and l is the length of the magnetic circuit), we know that the larger N is, the larger B is, and the greater the driving force is.

[0038] The driving force of the coil device described above is also related to the current in the conductor 3 and the number of turns in the stator winding 111. The greater the number of turns in the stator winding 111, the greater the driving force of the coil device. Conversely, the smaller the number of turns, the lighter the stator winding 111, the less material is used, and the lower the cost.

[0039] In the embodiments of this application, when N≥470, the stator winding 111 has a larger number of turns, and the coil device has a higher driving force. When N≤550, the stator winding 111 has a smaller number of turns, is lighter, and the coil device has a lower cost. Therefore, when 470≤N≤550, the coil device can achieve a balance of higher driving force, lighter weight, and lower cost.

[0040] Please refer to Figures 1-4 The outer diameter of the copper layer 32 of conductor 3 is d, which satisfies: 0.15mm≤d≤0.19mm.

[0041] The outer diameter of the copper layer 32 of the conductor 3 can be any one of 0.15mm, 0.155mm, 0.16mm, 0.165mm, 0.17mm, 0.175mm, 0.18mm, 0.185mm, or 0.19mm, or any value between two of them.

[0042] In some embodiments, the correspondence between the outer diameter of the copper layer 32 of the conductor 3 and the outer diameter of the conductor 3 including the enamel film is as follows: 0.14 mm (outer diameter of the copper layer 32 of the conductor 3) corresponds to 1.16 mm (outer diameter of the conductor 3 including the enamel film), 0.16 mm (outer diameter of the copper layer 32 of the conductor 3) corresponds to 0.182 mm (outer diameter of the conductor 3 including the enamel film), 0.17 mm (outer diameter of the copper layer 32 of the conductor 3) corresponds to 0.194 mm (outer diameter of the conductor 3 including the enamel film), and 0.18 mm (outer diameter of the copper layer 32 of the conductor 3) corresponds to 0.204 mm (outer diameter of the conductor 3 including the enamel film).

[0043] As mentioned above, R = ρL / S, where S is the cross-sectional area of ​​conductor 3, which is equivalent to the diameter of conductor 3, and also equivalent to the outer diameter of the copper layer 32 of conductor 3. The larger S is, the smaller R is, the larger I is, and the greater the driving force.

[0044] In this embodiment, when d ≥ 0.15 mm, the outer diameter of the copper layer 32 of the conductor 3 is larger, resulting in a larger driving force of the coil device. When d ≤ 0.19 mm, the outer diameter of the copper layer 32 of the conductor 3 is smaller, resulting in a lower cost for the conductor 3. Therefore, when 0.15 mm ≤ d ≤ 0.19 mm, the coil device can have both higher driving force and lower mass.

[0045] Please refer to Figures 1-4, 0.16mm≤d≤0.18mm.

[0046] In the embodiments of this application, when d≥0.16mm, the coil device has a greater driving force, and when d≤0.18mm, the coil device has a lower cost. Therefore, when 0.16mm≤d≤0.18mm, the coil device can achieve both greater driving force and lower cost.

[0047] In some embodiments, conductor 3 is copper-clad aluminum or aluminum, with a strength of 0.02251 Ω•mm. 2 / m≤ρ≤0.029Ω•mm 2 / m, 6.8mm≤H≤9mm, 0.15mm≤d≤0.19mm, 470≤N≤550.

[0048] As mentioned above, when R is constant, the larger U is, the larger I is, and the greater the driving force. Therefore, it is understandable that when the coil device is applied to the electronic expansion valve 100, the driving force of the coil device can be measured by the minimum operating voltage of the electronic expansion valve 100.

[0049] The following section uses the application of a coil device in an electronic expansion valve 100 as an example to conduct relevant tests, and briefly introduces the test method for the minimum operating voltage of the electronic expansion valve 100:

[0050] The electronic expansion valve 100 includes a valve body, a valve core assembly 20, and a rotor assembly 23. The valve body has a valve port 251. The rotor assembly 23 is configured to drive the valve core assembly 20 to move relative to the valve port 251 under the action of an excitation magnetic field through the transmission cooperation of a shaft component 22, thereby opening or closing the valve port 251 and even controlling the flow rate. The valve body includes a first channel 4 and a second channel 5. In the open position, refrigerant can flow from the second channel 5 into the first channel 4 through the valve port 251. In the closed position, refrigerant cannot flow from the second channel 5 into the first channel 4.

[0051] 1. Test conditions

[0052] Electronic expansion valve 100 specifications: rated voltage 12V.

[0053] 2. Test Procedure

[0054] 2.1 Initial Action Verification:

[0055] Apply a 12V voltage to drive shaft component 22 and close valve port 251;

[0056] Apply 12V voltage again to drive shaft component 22, open valve port 251, and confirm that the valve body operates normally.

[0057] 2.2 Cyclic pressure reduction test:

[0058] Circular sequence:

[0059] Closing phase: Drive shaft component 22 with 12V voltage to close valve port 251;

[0060] Turn-on phase: Drive shaft component 22 to perform the turn-on action by successively decreasing the voltage value by 0.2V (e.g., 11.8V, 11.6V...).

[0061] c. Termination condition: Continuously reduce the opening voltage until valve port 251 can no longer be opened.

[0062] 3. Minimum valve opening voltage determination:

[0063] Valve port 251 opening status monitoring:

[0064] Successful opening: After the shaft component 22 performs the opening action, the air pressure value of the second channel 5 is within the predetermined pressure range;

[0065] Startup failed: Air pressure value exceeds the preset range.

[0066] Threshold recording: The previous effective opening voltage when valve port 251 cannot be opened is recorded as the lowest valve opening voltage in a single test.

[0067] 4. Statistical Results:

[0068] Repeat the above test for 30 independent samples and record the lowest valve opening voltage for each sample;

[0069] Calculate the arithmetic mean of the 30 lowest development voltage values ​​as the final lowest operating voltage.

[0070] It should be noted that a difference of ±0.2V in the minimum operating voltage can be understood as the minimum operating voltage being basically the same.

[0071] The relevant parameters and performance tests of Comparative Example 1, Comparative Example 2, and Examples 1 to 4 are shown in Table 1:

[0072] Table 1:

[0073]

[0074] It should be noted that the wire diameter in Table 1 refers to the outer diameter of the copper layer 32 in copper-clad aluminum conductor 3, and to the outer diameter of the aluminum wire excluding the insulating varnish film 33 in aluminum conductor 3.

[0075] As shown in Table 1:

[0076] 1) As can be seen from Comparative Example 1 and Examples 1-4, the coil device in Examples 1-4 of this application has a driving force comparable to that of the coil device in Comparative Example 1, and the stator winding 111 has a lighter weight and the coil device has a lower cost.

[0077] 2) As can be seen from Comparative Examples 1, 2, and 1-4, although the copper-clad aluminum conductor 3 stator winding 111 in Comparative Example 2 is lighter than the copper conductor 3 stator winding 111 in Comparative Example 1, the axial length of the stator winding 111 in Comparative Example 2 is the same as that in Comparative Example 1, and the number of turns in Comparative Example 2 is reduced. Therefore, the driving force of the coil device in Comparative Example 2 is lower than that in Comparative Example 1. In contrast, the coil devices in Embodiments 1-4 of this application have higher driving force while also having a lighter stator winding 111.

[0078] It should be noted that: Please refer to Figure 2 and Figure 4 The stator winding 111 can be approximated as a cylinder. Taking the coil device that encapsulates the stator winding 111 with injection-molded resin material as an example, the encapsulation part 114 formed by the injection-molded material can be approximated as the outer surface of the encapsulated cylinder. When the encapsulation thickness remains constant, the change in outer surface area when the radius of the cylinder changes is significantly greater than the change in outer surface area when the height of the cylinder changes (outer surface area of ​​the cylinder S = 2πrh + 2πr). 2 (where h is the axial height of the cylinder and r is the radius of the cylinder). In other words, increasing the radial dimension of the stator winding 111 will significantly increase the amount of encapsulation 114 used, i.e., its weight, while increasing the axial height of the stator winding 111 will not significantly increase the amount of encapsulation 114 used, i.e., its weight. That is, while meeting the insulation and sealing requirements of the coil device, increasing the axial height of the stator winding 111 has a relatively small impact on the cost and weight of the coil device.

[0079] Taking a coil device made of copper-clad aluminum or aluminum wire 3 instead of copper wire 3 as an example, with the goal of achieving a driving force basically the same as that of a coil device including copper wire 3, while keeping the DC resistance R basically unchanged, the resistivity ρ of the wire increases, requiring a reduction in the number of turns N or an increase in the wire diameter. If the wire diameter remains unchanged and only the number of turns N is reduced, the reduction in the number of turns N will lead to a decrease in the driving force F. If the number of turns N remains unchanged and only the wire diameter is increased, the winding height H or the radial dimension of the stator winding 111 will increase. As mentioned above, compared to increasing the radial dimension of the stator winding 111, increasing the winding height H is beneficial for the coil device to have a lighter weight and lower cost. In addition, since the increase in the winding height H is beneficial for improving the driving force of the coil device, even if the number of turns N is further reduced, the coil device can maintain a high driving force. At the same time, the further reduction in the number of turns further reduces the weight and cost of the coil device. Please continue to refer to Table 1. Compared with Comparative Example 1, Embodiments 1-4 of this application have increased the wire diameter while reducing the number of turns N, and compensated for the loss of driving force by increasing the winding height H so that the driving force of Embodiments 1-4 is basically the same as that of Comparative Example 1. Furthermore, the stator winding 111 of Comparative Example 1 has a lighter weight.

[0080] Please refer to Figures 1-4 The coil frame 112 includes a cylindrical part 1123 and flanges located at both ends of the cylindrical part 1123. The stator winding 111 is located between the two flanges. The number of turns of the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylindrical part 1123 is n, which satisfies: 18≤n≤23.

[0081] It should be noted that the number of turns of the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylinder portion 1123 is different from the number of turns of the stator winding 111 mentioned above. Generally, the number of turns of the stator winding 111 is greater than the number of turns of the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylinder portion 1123. Understandably, since the number of turns of the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylinder portion 1123 is constant, a different number of turns in the stator winding 111 means that the radial width of the stator winding 111 is different.

[0082] Understandably, the number of turns of the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylinder 1123 refers to the number of turns of the conductor 3 arranged along the axial direction of the stator winding 111 and closest to the outer peripheral wall of the cylinder 1123. Alternatively, it can be referred to as the number of turns of the innermost loop of the conductor 3.

[0083] Understandably, when the total number of turns is constant, the number of turns of the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylinder 1123 is greater, which can reduce the number of turns piled up in the outer layer, thereby reducing the radial dimension of the stator winding 111. As mentioned above, this helps to reduce the weight and cost of the coil device. Since the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylinder 1123 is generally wound more tightly, the number of turns of the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylinder 1123 is less, which can make the conductor 3 of the stator winding 111 near the outer peripheral wall of the cylinder 1123 more sparse, which can reduce the risk of damage to the conductor 3 caused by the squeezing force between the conductors 3, and the coil device has higher reliability.

[0084] In the embodiments of this application, when n≥18, the coil device has lower weight and cost, and when n≤23, the coil device has higher reliability. When 18≤n≤23mm, the coil device can balance lower weight, lower cost, and higher reliability.

[0085] Please refer to Figures 1-4 The weight of stator winding 111 is G, which satisfies: 2.8g≤G≤3g.

[0086] The weight of the stator winding 111 can be any one of 2.8g, 2.9g, or 3g, or any value between two of them.

[0087] Understandably, for conductors of the same specification, the heavier the stator winding 111, the greater its number of turns and the greater the driving force of the coil device; the lighter the stator winding 111, the lower its cost.

[0088] In this embodiment, when G≥2.8g, the stator winding 111 has a larger weight and the driving force of the coil device is larger. When G≤3g, the stator winding 111 has a smaller weight and the cost of the stator winding 111 is lower. Therefore, when 2.8g≤G≤3g, the coil device can balance a larger driving force and a smaller weight.

[0089] Please refer to Figures 1-4 The inner diameter of stator winding 111 is D1, and the outer diameter of stator winding 111 is D2. 20.3mm≤D1≤21.3mm, 35mm≤D2≤36mm.

[0090] The inner diameter of the stator winding 111 can be any one of 20.3mm, 20.4mm, 20.5mm, 20.6mm, 20.7mm, 20.8mm, 20.9mm, 21mm, 21.1mm, 21.2mm, or 21.3mm, or any value between two of them.

[0091] The outer diameter of the stator winding 111 can be any one of 35mm, 35.1mm, 35.2mm, 35.3mm, 35.4mm, 35.5mm, 35.6mm, 35.7mm, 35.8mm, 35.9mm, or 36mm, or any combination thereof.

[0092] Understandably, the larger the outer diameter and the smaller the inner diameter of the stator winding 111, the greater the number of turns of the stator winding 111, and the greater the driving force of the coil device. The smaller the outer diameter and the larger the inner diameter of the stator winding 111, the lighter the weight of the stator winding 111, and the lower the cost of the coil device.

[0093] In this embodiment, when D1 ≥ 20.3 mm and D2 ≤ 36 mm, the stator winding 111 has a larger inner diameter and a smaller outer diameter, resulting in lower cost of the coil assembly. When D1 ≤ 21.3 mm and D2 ≥ 35 mm, the stator winding 111 has a smaller inner diameter and a larger outer diameter. Therefore, when 20.3 mm ≤ D1 ≤ 21.3 mm and 35 mm ≤ D2 ≤ 36 mm, the coil assembly can balance higher driving force and lower cost.

[0094] Please refer to Figures 1-4 The DC resistance of stator winding 111 is R, which satisfies: 45.8Ω≤R≤46.2Ω.

[0095] The DC resistance of stator winding 111 can be any one of 45.8Ω, 45.9Ω, 46Ω, 46.1Ω, 46.2Ω or any value between two of them.

[0096] Understandably, the larger the DC resistance, the greater the current it can withstand in a short time, the lower the risk of overheating and aging of the insulation layer of wire 3, and the longer the lifespan of the coil device; as mentioned above, the smaller the DC resistance, the greater the driving force of the coil device.

[0097] In this embodiment, when R ≥ 45.8 Ω, the DC resistance is relatively high, resulting in a longer lifespan for the coil device; when R ≤ 46.2 Ω, the driving force of the coil device is relatively high. Therefore, when 45.8 Ω ≤ R ≤ 46.2 Ω, the coil device can balance high driving force and long lifespan.

[0098] Please refer to Figures 1-4 This application provides an electronic expansion valve 100, which includes a coil device, a rotor assembly 23, and a sleeve 21 sleeved on the outer periphery of the rotor assembly 23. The coil device is sleeved on the outer periphery of the sleeve 21. The rated voltage of the electronic expansion valve 100 is 12V.

[0099] It should be noted that the rated voltage of the electronic expansion valve 100 is different from the minimum operating voltage of the electronic expansion valve 100.

[0100] In this embodiment, by controlling the resistivity of the conductor 3 and the axial length of the stator winding 111 within a reasonable range, the electronic expansion valve 100 using copper-clad aluminum or aluminum wire stator windings 111 can achieve a lower minimum operating voltage. This means that the electronic expansion valve 100 can drive the rotor assembly 23 to move and achieve the opening and closing of the electronic expansion valve 100 at a lower input voltage, thus giving the electronic expansion valve 100 higher operational stability. That is, under the premise that the rated voltage of the electronic expansion valve 100 is the same, the electronic expansion valve 100 including stator windings 111 made of copper-clad aluminum or aluminum wire and the electronic expansion valve 100 including stator windings 111 made of copper wire can maintain a basically consistent minimum operating voltage.

[0101] In some embodiments, please refer to Figures 1-4 This application provides an electronic expansion valve 100, which includes a shaft component 22, a nut assembly 24, a coil device, a valve body, a rotor assembly 23, and a valve core assembly 20. The valve body includes a housing, which includes a valve seat 25 and a sleeve 21. The valve seat 25 is disposed at one end of the sleeve 21 in the axial direction of the stator winding 111. The valve port 251 is disposed on the valve seat 25. The rotor assembly 23 is located on the inner circumferential side of the sleeve 21, and the stator assembly 11 is sleeved on the outer circumferential side of the sleeve 21.

[0102] The coil assembly includes a stator assembly 11 and an encapsulation member 114. The stator assembly 11 includes a first electromagnetic pole plate 1131, a second electromagnetic pole plate 1132, a stator winding 111, a coil frame 112, and pins 115. The first electromagnetic pole plate 1131 and the second electromagnetic pole plate 1132 are disposed on the outer periphery of the coil frame 112. The first electromagnetic pole plate 1131 includes a plurality of first claw poles 1131a, and the second electromagnetic pole plate 1132 includes a plurality of second claw poles 1132a. The first claw poles 1131a and the second claw poles 1132a are alternately arranged along the circumference of the stator winding 111. The encapsulation member 114 is injection molded from resin material and encapsulates part of the stator assembly 11. The encapsulation member 114 is not disposed between the first claw poles 1131a and the second claw poles 1132a. The coil frame 112 includes a cylindrical portion 1123, a first flange portion 1121, and a second flange portion 1122. The cylindrical portion 1123 connects the first flange portion 1121 and the second flange portion 1122. The first flange portion 1121 and the second flange portion 1122 are spaced apart along the axial direction of the stator winding 111, and the stator winding 111 is wound around the cylindrical portion 1123. An encapsulating member 114 fills the gap between the first flange portion 1121, the second flange portion 1122, the first electromagnetic pole plate 1131, and the stator winding 111. A pin 115 is connected to the coil frame 112 and electrically connected to the stator winding 111. The encapsulating member 114 covers a portion of the pin 115. Along the axial direction of the stator winding 111, the side of the first electromagnetic pole plate 1131 facing away from the stator winding 111 is covered with the encapsulating member 114. It should be noted that in the electronic expansion valve 100, the first claw pole 1131a and the second claw pole 1132a are a special type of motor rotor structure used to convert the axial excitation magnetic field generated by the stator winding 111 into a radial excitation magnetic field, thereby facilitating the rotation of the rotor assembly 23. The encapsulation member 114 has two opposing holes along the axial direction of the stator winding 111, and the sleeve 21 passes through the holes. The coil device is connected to the valve body.

[0103] The stator assembly 11 generates an excitation magnetic field. The valve core assembly 20 has an open position (open valve port 251) and a closed position (closed valve port 251). The rotor assembly 23 is located within the valve body and is configured to drive the valve core assembly 20 to switch between the open and closed positions under the action of the excitation magnetic field. A shaft component 22 is threadedly connected to a nut assembly 24, which is mounted in the housing. The rotor assembly 23 is rotatably disposed within the housing. Rotation of the rotor assembly 23 drives the shaft component 22 to move closer to or further away from the valve port 251 along the axial direction of the stator winding 111, thereby causing the shaft component 22 to drive the valve core assembly 20 to switch between the open and closed positions. Exemplarily, the valve core assembly 20 may include a valve needle body. Optionally, the valve needle body may be directly connected to the shaft component 22. Alternatively, please refer to... Figure 2 The valve needle body can also be indirectly connected to the shaft component 22, for example, through a transmission connection via a spring or other components.

[0104] The above examples illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely for the purpose of helping to understand the technical solutions and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A coil device for an electronic expansion valve, characterized by, include: Electromagnetic pole plates (1131, 1132), coil frame (112), and stator winding (111), wherein the stator winding (111) is wound around the coil frame (112), and the electromagnetic pole plates (1131, 1132) are disposed on the outer periphery of the coil frame (112); The conductor (3) of the stator winding (111) is made of copper-clad aluminum or aluminum, the resistivity of the conductor (3) is ρ, and the axial length of the stator winding (111) is H. Satisfies: 0.02251 Ω • mm 2 / m < p < 0.029 Ω • mm 2 / m, 6.8 mm < H < 9 mm.

2. The coil arrangement of claim 1, characterized in that 7.2mm≤H≤9mm.

3. The coil arrangement of claim 1, wherein, The conductor (3) of the stator winding (111) is made of copper-clad aluminum, and the copper content of the conductor (3) is C, satisfying: 15%≤C≤40%.

4. The coil arrangement of claim 1 or 2, characterized in that The number of turns of the stator winding (111) is N, which satisfies: 470≤N≤550.

5. The coil arrangement of claim 1 or 2, characterized in that The conductor (3) includes an aluminum core (31), a copper layer (32), and an insulating varnish film (33). The copper layer (32) is wrapped around the outside of the aluminum core (31), and the insulating varnish film (33) is wrapped around the outside of the copper layer (32). The outer diameter of the copper layer (32) of the conductor (3) is d, which satisfies: 0.15mm≤d≤0.19mm.

6. The coil arrangement of claim 5, wherein, 0.16mm≤d≤0.18mm.

7. The coil arrangement of claim 1, wherein The coil frame (112) includes a cylindrical part (1123) and flanges (1121, 1122) located at both ends of the cylindrical part (1123). The stator winding (111) is located between the two flanges (1121, 1122). The number of turns of the conductor (3) of the stator winding (111) near the outer peripheral wall of the cylindrical part (1123) is n, which satisfies: 18≤n≤23.

8. The coil arrangement of claim 1, wherein, The weight of the stator winding (111) is G, which satisfies: 2.8g≤G≤3g.

9. The coil arrangement of claim 1 or 2, characterized in that The inner diameter of the stator winding (111) is D1, and the outer diameter of the stator winding (111) is D2, where 20.3mm≤D1≤21.3mm and 35mm≤D2≤36mm.

10. The coil arrangement of claim 1, wherein, The DC resistance of the stator winding (111) is R, which satisfies: 45.8Ω≤R≤46.2Ω.

11. An electronic expansion valve characterized by include: The coil device, rotor assembly (23), and sleeve (21) sleeved on the outer periphery of the rotor assembly (23) as described in any one of claims 1-10, wherein the coil device is sleeved on the outer periphery of the sleeve (21); The rated voltage of the electronic expansion valve is 12V.

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