Thermostatic expansion valve

Abstract

A thermal expansion valve, comprising a gas tank head, the gas tank head comprising a gas tank cover, a gas tank seat, a diaphragm, a transmission part, a sealing plug, the diaphragm comprising a flat part, a sawtooth part and a fixed part, the flat part and the sawtooth part being located between the fixed part and the flat part, the fixed part being fixedly arranged with the gas tank cover and the gas tank seat, the sawtooth part comprising N tooth parts, the flat part being in the shape of a straight line segment, the fixed part being in the shape of a straight line segment, the tooth part being in the shape of two straight line segments connected together, an included angle θ being formed between the two straight line segments, 0°<θ<180°, and adjacent two tooth parts being connected with each other, the flat part being in the shape of a circle when viewed from above, the sawtooth part being in the shape of a circular ring, and the fixed part being in the shape of a circular ring, wherein N is a positive integer. The diaphragm has small stretching change during operation, the force on the position where the diaphragm is easy to break is small, the displacement is small, and the durability of the diaphragm is improved. By changing the size of the diaphragm and increasing the contact area of the fixed part and the transmission part, the opening degree is superior to the original structure.

Description

Technical Field

[0001] This invention relates to a thermostatic expansion valve, and more particularly to a miniaturized thermostatic expansion valve. Background Technology

[0002] Thermostatic expansion valve is an important automatic control component of refrigeration system. It uses the temperature change of the gas box head (temperature sensing bulb) as a signal to adjust the valve opening and change the refrigerant flow.

[0003] A typical thermostatic expansion valve consists of a valve body and a gas chamber head. The gas chamber head includes components such as a gas chamber cover, diaphragm, transmission part, and gas chamber seat. The diaphragm acts as a diaphragm, transmitting the force from the gas chamber cover to the transmission part. Its characteristics are determined by the material, state, thickness, and corrugation shape, and it is generally made of stainless steel or copper alloy.

[0004] Reference Figure 1 , Figure 1 The diagram shows an existing air chamber head 10 using a steel ball welded seal, including an air chamber cover 11, an air chamber seat 12, a diaphragm 13, a transmission part 14, and a sealing plug 15. The steel ball welded seal on the air chamber head has poor sealing performance; a head-type welded seal is proposed for structural optimization.

[0005] Reference Figure 2 , Figure 2 The diagram shows an existing headed gas chamber head 20, including a gas chamber cover 21, a gas chamber seat 22, a diaphragm 23, a transmission part 24, and a sealing plug 25. Because the headed sealing gas chamber cover sinks, the volume for storing refrigerant is relatively smaller compared to a ball-sealed gas chamber. This reduced volume makes filling difficult and degrades performance. To increase the volume, Figure 2 By reducing the straight section of the outer edge of the air box cover to increase the air box head cavity, the fit between the air box cover, diaphragm, and air box seat is expanded outward to form a new air box cover and air box seat. By reducing the straight section of the outer edge of the air box cover to increase the power head cavity, the deformation range of the diaphragm increases, which also leads to an increase in the bending moment of the diaphragm during movement and a decrease in the durability of the diaphragm. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the purpose of this invention is to provide a thermostatic expansion valve whose diaphragm has good durability under the condition of a large deformation range during normal operation, and the expansion valve opening is improved.

[0007] A thermostatic expansion valve includes a gas tank head, which comprises a gas tank cover, a gas tank seat, a diaphragm, a transmission part, and a sealing plug. The gas tank cover is fixedly disposed with the gas tank seat. The diaphragm is located between the gas tank cover and the gas tank seat. The transmission part is located on one side of the diaphragm, and the gas tank cover is located on the other side of the diaphragm. The sealing plug is located on one side of the gas tank cover. The diaphragm includes a straight portion, a serrated portion, and a fixing portion. The serrated portion is located between the fixing portion and the straight portion. The fixing portion is connected to the gas tank seat. The cover and the air box seat are fixedly installed. The serrated part includes N teeth. In cross-section, the straight part is in the shape of a straight line segment, and the fixed part is in the shape of a straight line segment. Each tooth includes two connected straight line segments, and the two straight line segments form an included angle θ, where 0° < θ < 180°. Adjacent teeth are connected to each other, and the connection between the two straight line segments is rounded. In top view, the straight part is circular, the serrated part is annular, and the fixed part is annular, where N is a positive integer greater than or equal to 2.

[0008] According to the present invention, the diaphragm has a straight portion, a serrated portion, and a fixed portion. By changing the structural form of the diaphragm, the amount of tensile change during operation is reduced, the stress on the easily broken parts of the diaphragm is reduced, the displacement is reduced, and the durability of the expansion valve diaphragm is improved. By changing the size of the diaphragm corrugations, the contact area between the fixed portion and the transmission plate is increased, resulting in an opening degree superior to the original structure. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of an existing air tank head that uses a steel ball welding sealing method;

[0010] Figure 2 This is a schematic diagram of an existing air box head that uses a capped design and includes an arc-shaped corrugated diaphragm;

[0011] Figure 3 This is a three-dimensional structural schematic diagram of an embodiment of the thermal expansion valve of the present invention;

[0012] Figure 4 This is another three-dimensional structural schematic diagram of an embodiment of the thermal expansion valve of the present invention;

[0013] Figure 5 This is a schematic diagram of an embodiment of the air box head of the present invention;

[0014] Figure 6 A cross-sectional view of a diaphragm according to an embodiment of the present invention;

[0015] Figure 7 for Figure 6 Cross-sectional view of the diaphragm;

[0016] Figure 8 for Figure 7 Enlarged schematic view of a portion of the left connecting segment of the diaphragm;

[0017] Figure 9 for Figure 7 Enlarged schematic view of a portion of the right connecting segment of the diaphragm;

[0018] Figure 10 This is a simulation result diagram of the pressure displacement of the expansion valve compared to an existing expansion valve in another embodiment of the present invention. Detailed Implementation

[0019] Referring now to the embodiments described in detail in the accompanying drawings. Numerous specific details are set forth in the following detailed description to provide a full understanding of the invention. However, those skilled in the art will understand that the invention can be practiced without these specific details. It should also be understood that the specific components, devices, and features illustrated in the drawings and described herein are merely exemplary and should not be considered limiting.

[0020] The thermostatic expansion valve is an important automatic control component in a refrigeration system. It uses the temperature change of the gas chamber head (temperature sensing bulb) as a signal to adjust the valve opening and thus change the refrigerant flow rate. For one embodiment of this invention, please refer to... Figure 3 As shown, Figure 3 The structure of a thermostatic expansion valve 100 is shown. The thermostatic expansion valve includes a gas tank head 30, a valve body 40, a transmission rod assembly 50, a valve core assembly 60, and an adjusting seat assembly 70. The gas tank head 30 is located at the top of the valve body 40, the transmission rod assembly 50 is located inside the valve body 40 and drivesly connects the gas tank head 30 and the valve core assembly 60, and the adjusting seat assembly 70 is located at the bottom of the valve body 40 and is used for the valve core assembly 60.

[0021] In one embodiment of the present invention, the valve body 40 includes a first interface 401, a second interface 402, a third interface 403, and a fourth interface 404. The valve body includes a first flow channel 411, a second flow channel 412, a third flow channel 413, and a fourth flow channel 414. The first interface 401 is one port of the first flow channel 411, the second interface 402 is one port of the second flow channel 412, the third interface 403 is one port of the third flow channel 413, and the fourth interface 404 is one port of the fourth flow channel 414. Fluid enters through the first interface 401, exits through the second interface 402 after the valve core assembly moves downward, enters through the third interface 403, and exits through the fourth interface 404. Alternatively, the second interface 402 and the fourth interface 404 can also serve as inlets, and the first interface 401 and the third interface 403 as outlets. The first interface 401, the second interface 402, the third interface 403, and the fourth interface 404 are connected to external pipelines.

[0022] Please refer to Figure 3 , 4As shown in Figure 5, the valve body 40 includes a first side portion 421, a second side portion 422, a third side portion 423, and a fourth side portion 424. The first side portion 421 and the third side portion 423 are disposed opposite to each other, and the second side portion 422 and the fourth side portion 424 are disposed opposite to each other. The first interface 401 and the third interface 403 are located on the first side portion 421, and the second interface 402 and the fourth interface 404 are located on the third side portion 423. The valve body 40 has a top opening 431, and the air box head 20 is partially located in the opening 431 of the valve body 40. The valve body 40 has a bottom opening 432. The valve body 40 includes a valve chamber 441, the valve core assembly 60 is located in the valve chamber 441, and a partial adjusting seat assembly 70 is located in the bottom opening 432 and the valve chamber 441. The valve chamber 441 is connected to the first flow channel 411. The transmission rod assembly 50 is located inside the valve body 40, and it drives the air box head 20 and the valve core assembly 60. That is, the transmission rod assembly 50 can convert the force exerted by the air box head 20 on the transmission rod assembly 50 into a force exerted by the transmission rod assembly 50 on the valve core assembly 60, allowing the valve core assembly 60 to move up and down. It should be noted that the air box head 20 may also not be mounted on the valve body, but can be arranged outside the valve body 40 in the form of a temperature sensing bulb.

[0023] One embodiment of the present invention is described with reference to Figure 6 As shown, the air box head 30 includes an air box cover 31, an air box seat 32, a diaphragm 33, a transmission part 34, and a sealing plug 35. The air box cover 31 is fixedly disposed with the air box seat 32. The diaphragm 33 is located between the air box cover 31 and the air box seat 32. The transmission part 34 is located on one side of the diaphragm 33, and the air box cover 31 is located on the other side of the diaphragm 33. The sealing plug 35 is located on the outside of the air box cover 31. Figures 7 to 9 The diaphragm 33 includes a straight portion 331, a serrated portion 332, and a fixing portion 333. The serrated portion 332 is located between the fixing portion 333 and the straight portion 331. The fixing portion 333 is fixed between the air box cover 31 and the air box seat 32. The serrated portion 332 includes N teeth. In cross-section, the straight portion 331 is in the shape of a straight line segment, the fixing portion 333 is in the shape of a straight line segment, and the teeth are in the shape of two straight line segments connected together, forming an included angle θ between the two straight line segments, 0°<θ<180°. Adjacent teeth are connected to each other, and the connecting point of the two straight line segments is rounded. In top view, the straight portion 331 is in the shape of a disc, the serrated portion 332 is in the shape of a ring, and the fixing portion 333 is in the shape of a ring, where N is a positive integer greater than or equal to 2. This diaphragm has a straight section, a serrated section, and a fixed section. By changing the diaphragm's structure, the amount of tensile change during operation is reduced, the stress on the easily broken parts of the diaphragm is reduced, and the displacement is minimized, thus improving the durability of the expansion valve diaphragm. By changing the diaphragm size, the contact area between the fixed section and the transmission plate is increased, resulting in a better opening degree than the original structure.

[0024] One embodiment of the present invention is described below. Figure 7 and Figure 8As shown, in cross-section, the serrated portion 332 includes a first tooth portion 3321 and a second tooth portion 3322. The first end a of the first straight segment L1 of the first tooth portion 3321 is connected to the straight portion 331. The second end b of the first straight segment L1 of the first tooth portion 3321 is connected to the first end c of the second straight segment L2 of the first tooth portion 3321. The second end d of the second straight segment L2 of the first tooth portion 3321 is connected to the first end e of the third straight segment L3 of the second tooth portion 3322. The second end f of the third straight segment L3 of the second tooth portion 3322 is connected to the first end g of the fourth straight segment L4 of the second tooth portion 3322. The second end h of the fourth straight segment L4 of the second tooth portion is connected to the fixing portion 333. The corners at the connection of the straight segments are rounded.

[0025] One embodiment of the present invention is described below. Figure 7 and Figure 8 As shown, in cross-section, the angle formed by the first straight segment L1 of the first tooth 3321 and the second straight segment L2 of the first tooth 3321 faces the air box cover 31; the angle formed by the second straight segment L2 of the first tooth 3321 and the third straight segment L3 of the second tooth 3322 faces the air box seat 32; and the angle formed by the third straight segment L3 of the second tooth 3322 and the fourth straight segment L4 of the second tooth 3322 faces the air box cover 31. In top view, the first tooth 3321 forms a first annular groove, and the second tooth 3322 forms a second annular groove.

[0026] One embodiment of the present invention, viewed in cross-section, see [reference needed]. Figure 8 As shown, the perpendicular distance between the first end of the first straight segment of the first tooth and the connection point of the straight portion and the central axis of the diaphragm is X2 / 2. The angle between the first straight segment of the first tooth and the straight segment of the straight portion is α. The perpendicular distance between the second end of the first straight segment of the first tooth and the first end of the second straight segment of the first tooth and the central axis of the diaphragm is A. The perpendicular distance between the second end of the first straight segment of the first tooth and the first end of the second straight segment of the first tooth and the straight segment of the straight portion and its extension is h. The angle between the third straight segment of the second tooth and the central axis of the second tooth is β. The perpendicular distance between the second end of the second straight segment of the first tooth and the first end of the first straight segment of the second tooth and the central axis of the diaphragm is B. The perpendicular distance between the second end of the second straight segment of the first tooth and the first end of the first straight segment of the second tooth and the straight segment of the fixing portion and its extension is h1.

[0027] Satisfying the relation:

[0028]

[0029] , where K is a constant.

[0030] From the cross-section, the straight section 331 and its extension are on the same straight line as the straight section 333 and its extension. Assembling the air box head can ensure better cooperation between the fixed part and the transmission plate.

[0031] The diaphragm uses a thin stainless steel plate with a thickness of 0.05~0.15mm, 8mm≤A≤9mm, 9mm≤B≤11mm, 14mm≤X2≤15mm, 0.3mm≤h≤0.5mm, 0≤h1≤0.2mm, and 0°≤α≤180°. The selection of this range of values ​​ensures that the serrated part of the diaphragm is shortened while also ensuring the durability of the diaphragm and the opening performance of the expansion valve.

[0032] In one embodiment of the present invention, the diaphragm 33 is made of a thin stainless steel plate with a thickness of 0.10 mm. From the cross-section, A=8.65 mm, B=10 mm, X2=14.9 mm, h=0.48 mm, h1=0.1 mm, α=157°. Under these conditions, the diaphragm durability and the opening degree of the expansion valve are superior.

[0033] In one embodiment of the present invention, durability performance can be summarized by the stress value at the vulnerable location. The simulation results of the diaphragm stress values ​​of this embodiment and existing structures are as follows:

[0034] Type of air box head Stress value at the upper welding position (MPa) Downstroke welding stress value / MPa Using the diaphragm of the present invention 879 797 Existing diaphragm structure 978.62 794.11

[0035] Table 1

[0036] As can be seen from Table 1, in this embodiment, when the diaphragm reaches its maximum displacement in the upper stroke, the maximum stress at the diaphragm weld is 879 MPa, and when the diaphragm reaches its maximum displacement in the lower stroke, the maximum stress at the diaphragm weld is 797 MPa. In the existing structure, the stress at the upper stroke weld position is 978.62 MPa, and the stress at the lower stroke weld position is 794.11 MPa. The stress at the upper stroke weld position of the diaphragm in this embodiment is less than that of the existing structure, and the stress at the lower stroke weld position of the diaphragm in this embodiment is also less than that of the existing structure. Therefore, the durability of the diaphragm in this embodiment is superior to that of the existing structure.

[0037] In one embodiment of the present invention, when A is a variable and other quantities are constant, B = 10 mm, X2 = 14.9 mm, h = 0.48 mm, h1 = 0.1 mm, α = 157°, the simulation results of the stress values ​​at the diaphragm's vulnerable location for different values ​​of A are as follows:

[0038] A value (mm) Stress value at the upper welding position (MPa) Stress value at the lower welding position (MPa) 9 1138 768.97 8.7 948.5 827.08 8.65 931.8 848.44 8.6 955.25 880.62

[0039] Table 2

[0040] As can be seen from Table 2, in this embodiment of the invention, as the value of A gradually decreases from 9 mm to 8.6 mm, the stress value of the diaphragm at the upper stroke welding position gradually decreases and then increases. When the value of A reaches 8.65 mm, the stress value at the upper stroke welding position reaches the minimum value of 931.8 MPa. As the value of A gradually decreases from 9 mm to 8.6 mm, the stress value of the diaphragm at the lower stroke welding position gradually increases. In summary, when the value of A reaches 8.65 mm, the durability performance of the diaphragm is better.

[0041] In one embodiment of the present invention, when α is a variable and other constant quantities are B=10mm, X2=14.9mm, h=0.48mm, h1=0.1mm, and A=8.65mm, the simulation results of the stress values ​​at the diaphragm's vulnerable location for different α values ​​are as follows:

[0042] α value Upper stroke welding position stress / MP Stress at the welding position during the next stroke / MP 155° 935.2 850.2 157° 931.8 848.44 160° 835.44 905

[0043] Table 3

[0044] As can be seen from Table 3, in this embodiment of the invention, as the value of α gradually increases from 155° to 160°, the stress value of the diaphragm at the upper stroke welding position gradually decreases. When the value of α reaches 160°, the stress value at the upper stroke welding position reaches the minimum value of 835.44. As the value of α gradually decreases from 155° to 160°, the stress value of the diaphragm at the lower stroke welding position first decreases and then increases. In summary, when the value of α reaches 157°, the durability performance of the diaphragm is better.

[0045] In one embodiment of the present invention, when h1 is a variable, and other constant quantities are B=10mm, X2=14.9mm, h=0.48mm, α=157°, and A=8.65mm, the simulation results of the stress values ​​at the diaphragm's vulnerable location for different α values ​​are as follows:

[0046] h1 value (mm) Upper stroke welding position stress / MP Stress at the welding position during the next stroke / MP 0 1004.1 728.5 0.1 931.8 848.44 0.15 965.6 899.5 0.2 865.5 925.8

[0047] Table 4

[0048] As can be seen from Table 4, in one embodiment of the present invention, as the value of h1 increases from 0 mm to 0.2 mm, the stress value of the diaphragm at the upper stroke welding position gradually decreases, and as the value of A increases from 0 mm to 0.2 mm, the stress value of the diaphragm at the lower stroke welding position increases. When h1 = 0.1 mm, the durability of the diaphragm is better.

[0049] In another embodiment of the present invention, the diaphragm of the expansion valve is made of a thin stainless steel plate with a thickness of 0.10 mm, A=8.65 mm, B=10 mm, X2=14.9 mm, h=0.48 mm, h1=0.1 mm, and α=157°. The simulation results of the pressure displacement of the existing expansion valve and the expansion valve of this embodiment at 0°C are shown in the figure. Figure 10 ,

[0050] from Figure 10 As can be seen from the data, under the same pressure conditions, the pressure displacement of the expansion valve in this embodiment is greater than that of the existing steel ball expansion valve, indicating that the opening degree of the expansion valve in this application is superior to that of the existing steel ball expansion valve.

[0051] In another embodiment of the present invention, the diaphragm thickness is different. The simulation results of the stress value and pressure displacement at the diaphragm breakage location for expansion valves with different diaphragm thicknesses are as follows:

[0052] Diaphragm thickness (mm) Upper stroke welding position stress / MP Stress at the welding position during the next stroke / MP Simulated pressure displacement / mm 0.1 931.8 848.44 0.145 0.12 864.53 789.02 0.103

[0053] Table 5

[0054] As can be seen from Table 5, the thicker the diaphragm, the smaller the stress value at the welding position during the upper and lower strokes, and the better the durability of the diaphragm. The thinner the diaphragm, the greater the pressure displacement and the better the opening.

[0055] It should be noted that the terms "first," "second," "third," etc., used in the above embodiments are merely for naming purposes and do not imply any order. The above embodiments are only for illustrating the present invention and are not intended to limit the technical solutions described herein. Although this specification has described the present invention in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify or make equivalent substitutions to the present invention. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A thermostatic expansion valve, comprising a gas tank head, the gas tank head including a gas tank cover, a gas tank seat, a diaphragm, a transmission part, and a sealing plug, wherein the gas tank cover is fixedly disposed with the gas tank seat, the diaphragm is located between the gas tank cover and the gas tank seat, the transmission part is located on one side of the diaphragm, the gas tank cover is located on the other side of the diaphragm, and the sealing plug is located on one side of the gas tank cover, characterized in that: The diaphragm includes a straight portion, a serrated portion, and a fixing portion. The serrated portion is located between the fixing portion and the straight portion. The fixing portion is fixedly disposed with the air box cover and the air box seat. The serrated portion includes N teeth. In cross-section, the straight portion is in the shape of a straight line segment, and the fixing portion is in the shape of a straight line segment. Each tooth includes two connected straight line segments. Adjacent teeth are connected to each other, and the two straight line segments form an included angle θ, where 0° < θ < 180°. The connection between the two straight line segments is rounded. In top view, the straight portion is circular, the serrated portion is annular, and the fixing portion is annular, where N is a positive integer greater than or equal to 2. The serrated portion includes a first tooth portion and a second tooth portion. The diaphragm is made of a thin stainless steel plate with a thickness of 0.1 to 0.12 mm, where 8.6 mm ≤ A ≤ 9 mm and 9 mm ≤ B ≤ 11 mm. The perpendicular distance between the second end of the first straight segment of the first tooth portion and the first end of the second straight segment of the first tooth portion and the central axis of the diaphragm is A. The perpendicular distance between the second end of the second straight segment of the first tooth portion and the first end of the first straight segment of the second tooth portion and the central axis of the diaphragm is B.

2. The thermostatic expansion valve according to claim 1, characterized in that: From the cross-section, the first end of the first straight segment of the first tooth is connected to the straight part, the second end of the first straight segment of the first tooth is connected to the first end of the second straight segment of the first tooth, the second end of the second straight segment of the first tooth is connected to the first end of the third straight segment of the second tooth, the second end of the third straight segment of the second tooth is connected to the first end of the fourth straight segment of the second tooth, and the second end of the fourth straight segment of the second tooth is connected to the fixed part. All connecting parts are rounded.

3. The thermostatic expansion valve according to claim 2, characterized in that: In cross-section, the angle formed by the first straight segment and the second straight segment of the first tooth is toward the air box cover, the angle formed by the second straight segment and the third straight segment of the first tooth is toward the air box seat, and the angle formed by the third straight segment and the fourth straight segment of the second tooth is toward the air box cover. In top view, the first tooth forms a first annular groove, and the second tooth forms a second annular groove.

4. The thermostatic expansion valve according to claim 3, characterized in that, In cross-section, the perpendicular distance between the point where the first end of the first straight segment of the first tooth connects to the point where the straight portion meets the central axis of the diaphragm is X² / 2. The angle between the first straight segment of the first tooth and the straight segment of the straight portion is α. The perpendicular distance between the point where the second end of the first straight segment of the first tooth connects to the point where the straight segment of the straight portion and its extension is h is h. The angle between the third straight segment of the second tooth and the central axis of the second tooth is β. The perpendicular distance between the point where the second end of the second straight segment of the first tooth connects to the point where the straight segment of the fixed portion and its extension is h1 is h1. Satisfying the relation: , where K is a constant.

5. The thermostatic expansion valve according to claim 4, characterized in that, From a cross-sectional perspective, the straight segment of the flat part and its extension are on the same plane as the straight segment of the fixed part and its extension.

6. The thermostatic expansion valve according to claim 5, characterized in that, 14mm≤X2≤15mm, 0.3mm≤h≤0.5mm, 0≤h1≤0.2mm, 0°≤α≤180°.

7. The thermostatic expansion valve according to claim 6, characterized in that, The diaphragm is a 0.1mm thick stainless steel sheet with A=8.65mm, B=10mm, X2=14.9mm, h=0.48mm, h1=0.1mm, and α=157°.

8. The thermostatic expansion valve according to any one of claims 1-7, characterized in that, The thermostatic expansion valve further includes a valve body, which includes a first interface, a second interface, a third interface, and a fourth interface. The valve body includes a first side, a second side, a third side, and a fourth side. The first side and the third side are opposite to each other, and the second side and the fourth side are opposite to each other. The first interface and the third interface are located on the first side, and the second interface and the fourth interface are located on the third side. The valve body includes a first flow channel, a second flow channel, a third flow channel, and a fourth flow channel. The first interface is the port of the first flow channel, and the second interface is the port of the second flow channel. The valve body also includes a valve chamber, through which the first flow channel and the second flow channel are connected. The third interface is the port of the third flow channel, and the fourth interface is the port of the fourth flow channel. The third flow channel and the fourth flow channel are connected.

9. The thermostatic expansion valve according to claim 8, characterized in that, The thermostatic expansion valve further includes a transmission rod assembly, a valve core assembly, and an adjusting seat assembly. The valve body has a top opening, with the air box head located at the top opening of the valve body. The valve body also has a bottom opening, with the adjusting seat assembly located at the bottom opening of the valve body. The valve core assembly and the adjusting seat assembly are at least partially located in the valve chamber. The transmission rod assembly is located inside the valve body and drives the air box head and the valve core assembly. The transmission rod assembly can convert the force exerted by the air box head on the transmission rod assembly into a force exerted by the transmission rod assembly on the valve core assembly, allowing the valve core assembly to move up and down under the action of the air box head.

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