Double-valve-element electromagnetic valve capable of being opened at constant pressure

Abstract

The constant-pressure opening double-valve-element electromagnetic valve comprises a valve body provided with an air inlet, an inflation inlet and an exhaust port, a valve element assembly is arranged in the valve body and comprises a first valve element and a second valve element, and an elastic piece is arranged between the first valve element and the second valve element; the valve element assembly has three states, in the first state, the air inlet and the air outlet are closed, and the force exerted on the valve body by the two valve elements is the same; in the second state, the air inlet communicates with the inflation inlet, and the exhaust port is closed; in the third state, the air inlet is closed, and the exhaust port communicates with the inflation port; the elastic force borne by the first valve element in the second state is larger than the elastic force borne by the second valve element in the third state. Due to the fact that the two valve elements bear different elastic forces during opening, the problem that electromagnetic forces needed during opening are different due to the fact that the air pressures borne by the two valve elements are different is solved, the starting voltages for opening the air inlet and the air outlet are the same, the situation that air inlet and air outlet are unbalanced in the working process of the electromagnetic valve is avoided, and the air pressure stability is enhanced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electromagnetic valves, in particular to a double-valve-core electromagnetic valve with constant-pressure opening. BACKGROUND

[0002] With the development of the vehicle traffic technical field, people have higher and higher requirements on the driving experience of vehicles, and a plurality of air bags are arranged on the automobile seat to improve the comfort of driving, a controller composed of a plurality of electromagnetic valves connected with the air bags is arranged to adjust the pressure in the air bags, so that the functions of massage or support are realized, in order to realize the related functions of the air bags, the electromagnetic valve needs to control the air bag to charge and discharge and keep the inflated state, most of the existing electromagnetic valves are provided with two valve cores which cooperate with each other to realize the above-mentioned three states, but under the action of gas pressure, the starting voltages required by the two valve cores to be opened are different, and the electromagnetic valve will appear the condition of unbalanced air intake and air exhaust in the working process, which affects the air pressure stability of the related system, and further may affect the whole controller. CONTENT OF THE UTILITY MODEL

[0003] The application aims at the above problems, and provides a double-valve-core electromagnetic valve with constant-pressure opening, which comprises:

[0004] A valve body, air inlets, air charging ports and air outlets are arranged on the valve body;

[0005] A valve core assembly is arranged in the valve body and comprises a first valve core and a second valve core, an elastic member is arranged between the first valve core and the second valve core, the valve core assembly has a first state, a second state and a third state, when being in the first state, the first valve core closes the air inlet, the second valve core closes the air outlet, and the force of the first valve core and the second valve core acting on the valve body is the same in size and opposite in direction; when being in the second state, the air inlet is communicated with the air charging port, and the second valve core closes the air outlet; when being in the third state, the first valve core closes the air inlet, and the air outlet is communicated with the air charging port; the elastic force of the elastic member acting on the first valve core in the second state is greater than the elastic force of the elastic member acting on the second valve core in the third state;

[0006] A control assembly is arranged for controlling the valve core assembly to switch between the first state, the second state and the third state.

[0007] According to the technical scheme provided in some embodiments of the present application, the valve core assembly further comprises a fixed iron, which is arranged between the first valve core and the second valve core, and is sleeved on the elastic member; the elastic member comprises a first segment and a second segment which are integrally connected; the diameter and stiffness coefficient of the first segment are greater than those of the second segment; the free end of the first segment abuts against the first valve core, and the elastic force of the first segment acts on the first valve core and the fixed iron respectively; the free end of the second segment abuts against the second valve core, and the elastic force of the second segment acts on the first segment and the second valve core respectively.

[0008] According to the technical scheme provided in some embodiments of the present application, the fixed iron has a flow-through cavity inside; the flow-through cavity comprises a first cavity and a second cavity which are integrally connected; the inner diameter of the first cavity is greater than that of the second cavity; the diameter of the first segment matches the inner diameter of the first cavity; and the diameter of the second segment matches the inner diameter of the second cavity.

[0009] According to the technical scheme provided in some embodiments of the present application, the fixed iron has a flow-through cavity inside; the flow-through cavity comprises a first cavity and a second cavity which are integrally connected; the inner diameter of the first cavity is greater than that of the second cavity; the diameter of the first segment matches the inner diameter of the first cavity; and the diameter of the second segment matches the inner diameter of the second cavity.

[0010] According to the technical scheme provided in some embodiments of the present application, the first valve core has a first position and a second position; when in the first position, the first valve core closes the air inlet; and when in the second position, the air inlet is communicated with the air charging port through the air inlet cavity.

[0011] According to the technical scheme provided in some embodiments of the present application, the second valve core has a third position and a fourth position; when in the third position, the second valve core closes the air outlet; and when in the fourth position, the air charging port is communicated with the air exhaust port through the air inlet cavity, the fixed iron inside and the air outlet cavity.

[0012] According to the technical scheme provided in some embodiments of the present application, the control assembly comprises a first coil and a second coil; the magnetic field intensity generated after the first coil and the second coil are energized is the same and the directions are opposite; the first coil is sleeved on the valve body at a position corresponding to the air inlet cavity, and is used for moving the first valve core from the first position to the second position; and the second coil is sleeved on the valve body at a position corresponding to the air outlet cavity, and is used for moving the second valve core from the third position to the fourth position.

[0013] According to the technical scheme provided in the embodiments of the present application, the valve body comprises a first valve body and a second valve body, the first valve body is provided with the air inlet and the air charging port, the second valve body is provided with the air outlet, and the permanent magnet is arranged in the first valve body and the second valve body respectively.

[0014] According to the technical scheme provided in the embodiments of the present application, the first yoke is arranged on the first valve body and used for enhancing the electromagnetic force borne by the first valve core, and the second yoke is arranged on the second valve body and used for enhancing the electromagnetic force borne by the second valve core.

[0015] According to the technical scheme provided in the embodiments of the present application, the permanent magnet is sleeved with a first sealing ring and a second sealing ring, and is sealingly connected with the first valve body through the first sealing ring and sealingly connected with the second valve body through the second sealing ring.

[0016] Compared with the prior art, the present application has the following beneficial effects: the present application provides a constant-pressure opening double-valve-core electromagnetic valve, which comprises a valve body, an air inlet, an air charging port and an air outlet are arranged on the valve body, a valve core assembly is arranged in the valve body, the valve core assembly comprises a first valve core and a second valve core, an elastic member is arranged between the first valve core and the second valve core, the valve core assembly has a first state, a second state and a third state, when being in the first state, the first valve core closes the air inlet and the second valve core closes the air outlet, the force acting on the valve body by the first valve core and the second valve core is the same in size and opposite in direction, when being in the second state, the air inlet is communicated with the air charging port and the second valve core closes the air outlet, when being in the third state, the first valve core closes the air inlet and the air outlet is communicated with the air charging port, the elastic force of the elastic member acting on the first valve core in the second state is greater than the elastic force of the elastic member acting on the second valve core in the third state, the control assembly is used for controlling the valve core assembly to switch between the first state, the second state and the third state, by arranging the elastic member, the elastic forces borne by the two valve cores when being opened are different, so as to solve the problem that the electromagnetic forces required for opening the two valve cores are different due to different gas pressures, and then the starting voltages required for opening the air inlet and the air outlet are the same, the imbalance of the air inlet and the air outlet in the working process of the electromagnetic valve is avoided, and the air pressure stability of the related system is enhanced.

[0017] It should be understood that the description of technical features, technical solutions, advantages or similar language in this application does not imply that all features and advantages can be realized in any single embodiment. On the contrary, it can be understood that the description of a feature or advantage means that the specific technical feature, technical solution or advantage is included in at least one embodiment. Therefore, the description of technical features, technical solutions or advantages in this specification does not necessarily refer to the same embodiment. Further, the technical features, technical solutions and advantages described in this embodiment can be combined in any appropriate manner. Those skilled in the art will understand that the embodiments can be implemented without one or more specific technical features, technical solutions or advantages of the specific embodiments. In other embodiments, additional technical features and advantages can be identified in specific embodiments that do not embody all embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0019] Figure 1 A cross-sectional structure schematic diagram of a constant-pressure opening double-valve core electromagnetic valve in a first state according to an embodiment of the present application is shown in the figure.

[0020] Figure 2 A cross-sectional structure schematic diagram of a constant-pressure opening double-valve core electromagnetic valve in a second state according to an embodiment of the present application is shown in the figure.

[0021] Figure 3 A cross-sectional structure schematic diagram of a constant-pressure opening double-valve core electromagnetic valve in a third state according to an embodiment of the present application is shown in the figure.

[0022] Figure 4 A structure schematic diagram of an elastic member of a constant-pressure opening double-valve core electromagnetic valve according to an embodiment of the present application is shown in the figure.

[0023] Figure 5 A structure schematic diagram of a fixed iron of a constant-pressure opening double-valve core electromagnetic valve according to an embodiment of the present application is shown in the figure.

[0024] The text annotations in the figure represent:

[0025] 1, valve body; 2, first valve core; 3, second valve core; 4, fixed iron; 5, elastic member; 6, first yoke iron; 7, second yoke iron; 11, first valve body; 12, second valve body; 13, air inlet; 14, inflation port; 15, exhaust port; 41, first cavity; 42, second cavity; 43, first sealing ring; 44, second sealing ring; 51, first section; 52, second section; 111, air inlet cavity; 121, exhaust cavity. DETAILED DESCRIPTION

[0026] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings, and the description in this part is only exemplary and explanatory, and should not have any limiting effect on the protection scope of the present application. Specifically, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0027] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0028] As mentioned in the background, to solve the problems in the prior art, the present embodiment provides a constant-pressure opening double-valve core electromagnetic valve, comprising:

[0029] Valve body 1, the valve body 1 is provided with air inlet 13, inflation port 14 and exhaust port 15;

[0030] A valve core assembly, disposed within the valve body 1, includes a first valve core 2 and a second valve core 3. An elastic element 5 is disposed between the first valve core 2 and the second valve core 3. The valve core assembly has a first state, a second state, and a third state. In the first state, the first valve core 2 closes the air inlet 13, and the second valve core 3 closes the exhaust port 15. The forces exerted by the first valve core 2 and the second valve core 3 on the valve body 1 are of the same magnitude but opposite in direction. In the second state, the air inlet 13 is connected to the air filling port 14, and the second valve core 3 closes the exhaust port 15. In the third state, the first valve core 2 closes the air inlet 13, and the exhaust port 15 is connected to the air filling port 14. In the second state, the elastic force exerted by the elastic element 5 on the first valve core 2 is greater than the elastic force exerted by the elastic element 5 on the second valve core 3 in the third state.

[0031] The control component is used to control the valve core assembly to switch between the first state, the second state, and the third state.

[0032] like Figures 1-3 As shown, the solenoid valve in this embodiment is applied to the pneumatic system of an automobile seat. Multiple solenoid valves can form a controller to control the air-using components of the pneumatic system to achieve massage or support functions. The air-using components mostly adopt combined airbags or air bags. The internal space of the valve body 1 is connected to the air inlet 13, the inflation port 14, and the exhaust port 15 respectively. The air inlet 13 is used to connect to the air source device, the inflation port 14 is used to connect to the air-using components, and the exhaust port 15 is connected to the external environment. The first valve core 2 is set corresponding to the air inlet 13, and the second valve core 3 is set corresponding to the exhaust port 15. The elastic element 5 is formed by integrally connecting springs with different stiffness coefficients at both ends. The valve core assembly is set inside the valve body 1 to control the opening and closing of the air inlet 13 and the exhaust port 15, thereby realizing the inflation / deflation of the air-using components or maintaining the inflation state. Initially, the solenoid valve is in the closed state, the first valve core 2 closes the air inlet 13, and the second valve core 3 closes the exhaust port 15, that is, the first state mentioned above. When the gas-using component needs to be inflated, the first valve core 2 opens the air inlet 13, and the second valve core 3 keeps the exhaust port 15 closed. The gas output from the gas source device enters the gas-using component through the air inlet 13, the inside of the valve body 1, and the inflation port 14, which is the second state described above. When the gas-using component needs to be kept in an inflated state, the first valve core 2 closes the air inlet 13, and the second valve core 3 keeps the exhaust port 15 closed, and the gas-using component maintains an inflated state, which is the first state described above. When the gas in the gas-using component needs to be discharged, the first valve core 2 keeps the air inlet 13 closed, and the second valve core 3 opens the exhaust port 15. The gas in the gas-using component is discharged to the external environment through the air inlet 13, the inside of the valve body 1, and the exhaust port 15, which is the third state described above. The control component is located on the valve body 1 and can generate a magnetic field after being energized, thereby controlling the first valve core 2 and the second valve core 3 to move inside the valve body 1, opening the air inlet 13 or the exhaust port 15, so that the valve core component can switch between the three states.

[0033] In a traditional solenoid valve structure, the first valve core 2 and the second valve core 3 are subjected to the same gas pressure direction. However, because the two valve cores open in different directions, and the elastic force that needs to be overcome when the two valve cores open is the same, the first valve core 2 and the second valve core 3 require different starting voltages to open the air inlet 13 and the exhaust port 15, respectively. By setting the elastic element 5, the elastic force that the two valve cores are subjected to when opening is different, so as to solve the problem that the electromagnetic force required for opening the two valve cores is different due to the different gas pressures they are subjected to. This ensures that the starting voltage required to open the air inlet 13 and the exhaust port 15 is the same, avoids the situation of unbalanced air intake and exhaust during the operation of the solenoid valve, and enhances the air pressure stability of the relevant system.

[0034] In a preferred embodiment, the valve core assembly further includes a fixed iron 4, which is disposed between the first valve core 2 and the second valve core 3. The fixed iron 4 is sleeved on the elastic member 5. The elastic member 5 includes a first segment 51 and a second segment 52 integrally connected. The diameter and stiffness coefficient of the first segment 51 are greater than those of the second segment 52. The free end of the first segment 51 abuts against the first valve core 2, and the elastic force of the first segment 51 acts on the first valve core 2 and the fixed iron 4 respectively. The free end of the second segment 52 abuts against the second valve core 3, and the elastic force of the second segment 52 acts on the first segment 51 and the second valve core 3 respectively.

[0035] In a preferred embodiment, the fixed iron 4 has a flow cavity inside, which includes a first cavity 41 and a second cavity 42 that are integrally connected. The inner diameter of the first cavity 41 is larger than the inner diameter of the second cavity 42. The diameter of the first segment 51 matches the inner diameter of the first cavity 41, and the diameter of the second segment 52 matches the inner diameter of the second cavity 42.

[0036] like Figure 4 and Figure 5 As shown, the fixed iron 4 has a hollow structure with a flow cavity inside. Toothed notches are also provided circumferentially at both ends of the fixed iron 4. When the valve core abuts against one end of the fixed iron 4, the flow cavity inside the fixed iron 4 can communicate with the interior of the valve body 1 through the toothed notches. The flow cavity includes an integrally connected first cavity 41 and a second cavity 42. The inner diameter of the first cavity 41 is larger than the inner diameter of the second cavity 42, forming a stepped structure in the flow cavity. The elastic element 5 includes a first section 51 and a second section 52. The diameter and stiffness coefficient of the first section 51 are larger than those of the second section 42. The diameter and stiffness coefficient of section 52; In a conventional solenoid valve, the first valve core 2 and the second valve core 3 are connected by a spring with a constant stiffness coefficient. Since the first valve core 2 experiences gas pressure towards the exhaust port 15 when closing the inlet 13, and the second valve core 3 experiences gas pressure towards the exhaust port 15 when closing the exhaust port 15, the electromagnetic force required to open them is different when the elastic forces are the same. In this embodiment, the electromagnetic force required to open the inlet 13 should satisfy:

[0037]

[0038] Among them, F 弹1 For the elastic force of the first segment 51, F 进 The gas source device applies gas pressure to the first valve core 2 at the air inlet 13;

[0039] The electromagnetic force required to open exhaust port 15 should satisfy:

[0040]

[0041] Among them, F 弹2 For the elastic force of segment 52, F 内 The gas pressure applied to the second valve core 3 when the gas assembly is in the inflation state; because the first section 51 abuts against the inside of the fixed iron 4, F 弹1 The value is equal to F 弹2 The value of F is the sum of the value of the elastic force exerted on the fixed iron 4 by the first segment 51. 弹1 Greater than F 弹2 This allows the air intake 13 and the exhaust 15 to open with the same voltage.

[0042] In a preferred embodiment, the valve body 1 includes a first valve body 11 and a second valve body 12. The first valve body 11 has an air inlet 13 and an air filling port 14, and the second valve body 12 has an exhaust port 15. The two ends of the fixed iron 4 are respectively inserted into the first valve body 11 and the second valve body 12.

[0043] like Figures 1-3 As shown, the valve body 1 includes a first valve body 11 and a second valve body 12. The two ends of the fixed iron 4 are respectively inserted into the first valve body 11 and the second valve body 12, thereby fixing the first valve body 11 and the second valve body 12 to each other.

[0044] In a preferred embodiment, an air intake chamber 111 and an exhaust chamber 121 are formed between the two ends of the fixed iron 4 and the valve body 1, respectively, and are connected through the interior of the fixed iron 4. The air intake chamber 111 is connected to the air inlet 13 and the air filling port 14, and is provided with a first valve core 2 inside. The exhaust chamber 121 is connected to the exhaust port 15, and is provided with a second valve core 3 inside.

[0045] like Figures 1-3 As shown, an air intake chamber 111 is formed between the fixed iron 4 and the first valve body 11, and an exhaust chamber 121 is formed between the fixed iron 4 and the second valve body 12. The air intake chamber 111 and the exhaust chamber 121 can be connected through a flow chamber. A first valve core 2 is provided in the air intake chamber 111. By controlling the movement of the first valve core 2 in the air intake chamber 111, the opening and closing of the air intake port 13 can be controlled. A second valve core 3 is provided in the exhaust chamber 121. By controlling the movement of the second valve core 3 in the exhaust chamber 121, the opening and closing of the exhaust port 15 can be controlled.

[0046] In a preferred embodiment, the first valve core 2 has a first position and a second position, when in the first position, the first valve core 2 closes the air inlet 13, when in the second position, the air inlet 13 is communicated with the air inlet 14 through the air cavity 111.

[0047] In a preferred embodiment, the second valve core 3 has a third position and a fourth position, when in the third position, the second valve core 3 closes the air outlet 15, when in the fourth position, the air inlet 14 is communicated with the air outlet through the air cavity 111, the inside of the fixed iron 4 and the air cavity 121.

[0048] In a preferred embodiment, the control assembly includes a first coil and a second coil, the first coil and the second coil generate magnetic fields of the same strength and opposite directions after energization, the first coil is sleeved on the valve body 1 at a position corresponding to the air cavity 111, for moving the first valve core 2 from the first position to the second position; the second coil is sleeved on the valve body 1 at a position corresponding to the air cavity 121, for moving the second valve core 3 from the third position to the fourth position.

[0049] As shown in Figures 1-3 , the first coil and the second coil are two identical coils, the first valve core 2 is sleeved on the first valve body 11, the second valve core 3 is sleeved on the second valve body 12, both are electrically connected with the vehicle power supply, and the current directions in the first coil and the second coil are opposite, so that the first coil and the second coil generate magnetic fields of the same strength and opposite directions after energization, and the electromagnetic forces received by the first valve core 2 and the second valve core 3 are of the same size and opposite directions, that is, the starting voltage required to open the air inlet 13 and the air outlet 15 is the same; when the first coil is not energized, the first valve core 2 abuts against the inner wall of the air cavity 111 away from the fixed iron 4 and closes the air inlet 13, that is, the above-mentioned first position, when the first coil is energized, the first valve core 2 moves to the side of the fixed iron 4 under the action of the magnetic field generated by the first coil and abuts against the fixed iron 4, that is, the above-mentioned second position, at this time the air inlet 13 is communicated with the air inlet 14 through the air cavity 111; when the second coil is not energized, the second valve core 3 abuts against the inner wall of the air cavity 121 away from the fixed iron 4 and closes the air outlet 15, that is, the above-mentioned third position, when the second coil is energized, the second valve core 3 moves to the side of the fixed iron 4 under the action of the magnetic field generated by the second coil and abuts against the fixed iron 4, that is, the above-mentioned fourth position, at this time the air inlet 14 is communicated with the air outlet through the air cavity 111, the inside of the fixed iron 4 and the air cavity 121.

[0050] In a preferred embodiment, it also includes a first yoke 6 and a second yoke 7, the first yoke 6 is arranged on the first valve body 11, for enhancing the electromagnetic force received by the first valve core 2; the second yoke 7 is arranged on the second valve body 12, for enhancing the electromagnetic force received by the second valve core 3.

[0051] As Figures 1-3 shown, the first yoke 6 and the second yoke 7 are both U-shaped structures, the two ends of the first yoke 6 are respectively clamped on the first valve body 11 and the fixed iron 4, so that the first valve body 11 and the fixed iron 4 are relatively fixed, the two ends of the second yoke 7 are respectively clamped on the second valve body 12 and the fixed iron 4, so that the second valve body 12 and the fixed iron 4 are relatively fixed; the first yoke 6 is correspondingly arranged with the first coil, which can close the magnetic lines generated by the first coil inside, for enhancing the magnetic field generated by the first coil when energized, the second yoke 7 is correspondingly arranged with the second coil, which can close the magnetic lines generated by the second coil inside, for enhancing the magnetic field generated by the second coil when energized.

[0052] In a preferred embodiment, the fixed iron 4 is sleeved with a first sealing ring 43 and a second sealing ring 44, the fixed iron 4 is sealingly connected with the first valve body 11 through the first sealing ring 43, and is sealingly connected with the second valve body 12 through the second sealing ring 44.

[0053] As Figures 1-3 shown, the first sealing ring 43 is arranged between the fixed iron 4 and the first valve body 11, so that the outer wall of the fixed iron 4 is sealingly connected with the inner wall of the first valve body 11, the second sealing ring 44 is arranged between the fixed iron 4 and the second valve body 12, so that the outer wall of the fixed iron 4 is sealingly connected with the inner wall of the second valve body 12, by arranging the first sealing ring 43 and the second sealing ring 44, the air inlet cavity 111 and the air outlet cavity 121 can only be communicated through the flow-through cavity, avoiding the air leakage problem at the connection between the first valve body 11 and the second valve body 12 and the fixed iron 4.

[0054] In this paper, specific examples are applied to explain the principles and implementation modes of the application, and the above examples are only used to help understand the method and its core idea. The above description is only the preferred embodiment of the application, it should be pointed out that due to the limitation of language expression, there are infinite specific structures, for ordinary skilled in the art, without departing from the principles of the application, some improvements, refinements or changes can be made, or the above technical features can be combined in a proper way; these improvements, refinements, changes or combinations, or the application of the concept and technical scheme of the application to other occasions without improvement, should be regarded as the protection scope of the application.

Claims

1. A constant pressure opening two spool solenoid valve characterized by, The utility model relates to a valve body (1) is provided with intake port (13), inflation port (14) and exhaust port (15) on the valve body (1), the valve core subassembly is located in the valve body (1), and the valve core subassembly includes first valve core (2) and second valve core (3), and the elastic member (5) is arranged between first valve core (2) and second valve core (3), and the valve core subassembly has first state, second state and third state, when being in first state, first valve core (2) closes intake port (13), and second valve core (3) closes exhaust port (15), and the force that first valve core (2) and second valve core (3) act on valve body (1) is same in size and opposite in direction, when being in second state, intake port (13) is communicated with inflation port (14), and second valve core (3) closes exhaust port (15), when being in third state, first valve core (2) closes intake port (13), and exhaust port (15) is communicated with inflation port (14), and the elastic force that elastic member (5) acts on first valve core (2) when second state is greater than the elastic force that elastic member (5) acts on second valve core (3) when third state, control assembly is used to control the valve core subassembly switches between first state, second state and third state. The valve core subassembly further includes fixed iron (4), the fixed iron (4) is located between first valve core (2) and second valve core (3), the fixed iron (4) is sleeved on the elastic member (5), the elastic member (5) includes integral first section (51) and second section (52), the diameter and stiffness coefficient of first section (51) are greater than the diameter and stiffness coefficient of second section (52), the free end of first section (51) is abutted on first valve core (2), and the elastic force of first section (51) is respectively acted on first valve core (2) and fixed iron (4), the free end of second section (52) is abutted on second valve core (3), and the elastic force of second section (52) is respectively acted on first section (51) and second valve core (3). The fixed iron (4) has flow-through cavity inside, the flow-through cavity includes integral first cavity (41) and second cavity (42), the inner diameter of first cavity (41) is greater than the inner diameter of second cavity (42), the diameter of first section matches the inner diameter of first cavity (41), and the diameter of second section matches the inner diameter of second cavity (42). The fixed iron (4) is formed with intake cavity (111) and exhaust cavity (121) that are communicated through the inside of fixed iron (4) between both ends and valve body (1) respectively, the intake cavity (111) is communicated with intake port (13) and inflation port (14), and is provided with first valve core (2) inside, and the exhaust cavity (121) is communicated with exhaust port (15), and is provided with second valve core (3) inside.

2. The dual spool solenoid valve having a constant opening pressure according to claim 1, wherein ​ 3. The dual spool solenoid valve having a constant opening pressure according to claim 2, wherein ​ 4. The dual spool solenoid valve having a constant opening pressure according to claim 3, wherein ​ 5. The dual spool solenoid valve having a constant opening pressure according to claim 4, wherein The first valve core (2) has a first working position and a second working position, when in the first working position, the first valve core (2) closes the air inlet (13), when in the second working position, the air inlet (13) is communicated with the air inlet (14) through the air cavity (111).

6. The dual spool solenoid valve having a constant opening pressure according to claim 5, wherein The second valve core (3) has a third working position and a fourth working position, when in the third working position, the second valve core (3) closes the air outlet (15), when in the fourth working position, the air inlet (14) is communicated with the air outlet (15) through the air cavity (111), the inside of the fixed iron (4) and the air cavity (121).

7. The dual spool solenoid valve having a constant opening pressure according to claim 6, wherein The control assembly includes a first coil and a second coil, the magnetic field intensity generated by the first coil and the second coil after energization is the same and the direction is opposite, the first coil is sleeved on the valve body (1) corresponding to the position of the air cavity (111), used for moving the first valve core (2) from the first working position to the second working position; the second coil is sleeved on the valve body (1) corresponding to the position of the air cavity (121), used for moving the second valve core (3) from the third working position to the fourth working position.

8. The dual spool solenoid valve having a constant opening pressure according to claim 2, wherein The valve body (1) includes a first valve body (11) and a second valve body (12), the first valve body (11) is provided with the air inlet (13) and the air inlet (14), the second valve body (12) is provided with the air outlet (15), and the fixed iron (4) is respectively arranged in the first valve body (11) and the second valve body (12).

9. The dual spool solenoid valve having a constant opening pressure according to claim 8, wherein It also includes a first yoke iron (6) and a second yoke iron (7), the first yoke iron (6) is arranged on the first valve body (11), used for enhancing the electromagnetic force received by the first valve core (2); the second yoke iron (7) is arranged on the second valve body (12), used for enhancing the electromagnetic force received by the second valve core (3).

10. The dual spool solenoid valve having a constant opening pressure according to claim 8, wherein The fixed iron (4) is sleeved with a first sealing ring (43) and a second sealing ring (44), the fixed iron (4) is sealingly connected with the first valve body (11) through the first sealing ring (43), and is sealingly connected with the second valve body (12) through the second sealing ring (44).

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