A micro proportional valve

Abstract

The present invention relates to the technical field of proportional valves, and specifically to a micro proportional valve, including a valve body, a static armature, a coil, a valve core, a spring and a positioning member; the valve body includes a housing and a valve seat, a fluid inlet and a fluid outlet are provided on the valve seat, and a fluid channel is provided between the fluid inlet and the fluid outlet; the static armature and the coil are built into the valve body, and the coil is arranged around the static armature; the valve core and the static armature are arranged coaxially, and part of the valve core is limited between the spring and the valve seat, and the valve core moves axially under the action of electromagnetic force to open and close the fluid channel; the positioning member has multiple positioning surfaces, and is configured to synchronously realize the positioning of the valve body, the coil, the static armature, the valve core and the spring. As a result, the entire micro proportional valve has fewer parts and components, and the spatial integration is higher, which can fully meet the design requirements of miniaturization; at the same time, based on the role of the positioning member, the control accuracy problem of the traditional structure due to a large number of matching tolerance problems is reduced, and the overall performance is better.

Description

Technical Field

[0001] The invention relates to the technical field of proportional valves, and in particular to a micro proportional valve. Background Art

[0002] In many fields such as industrial automation control, fluid delivery systems, and medical devices, valves play a key role in accurately regulating fluid flow, pressure, and direction. Proportional valves are devices that can continuously control fluid parameters in proportion to input electrical signals. Compared with traditional switch valves, proportional valves have higher control accuracy and flexibility, and are therefore widely used. With the continuous development of science and technology, the trend of miniaturization and miniaturization of equipment is becoming increasingly obvious, and the demand for miniature proportional valves has also emerged and continues to grow.

[0003] At present, in terms of structural design, there are too many parts used to make up the structure of the micro proportional valve. A large number of parts not only occupy a large space volume, making it difficult to install and use the proportional valve in micro equipment or systems with strict space requirements, but also the connection and assembly between many parts increase the complexity and cost of the manufacturing process. Factors such as the matching tolerance and friction between parts will affect the control accuracy of the micro proportional valve, and also reduce the overall reliability and stability. When a micro proportional valve fails, too many parts will make fault diagnosis and maintenance more complicated, and a large number of parts will take more man-hours to assemble.

[0004] In terms of performance, the accuracy and dynamic response characteristics of traditional proportional valves are difficult to meet the requirements of miniaturized applications. Due to their large size, when controlling small flows or pressures, factors such as the inertia and viscosity of the fluid and the inertia of moving parts such as the valve core have a significant negative impact on the control accuracy and response speed.

[0005] In terms of assembly process, different parts are positioned with different fixings. Generally, the valve core is guided and positioned by the valve seat at the lower end. At this time, the valve core needs to be installed on the valve seat during the assembly process, and then the structure assembled in the shell is buckled onto the valve seat. During the buckling process, the parts will fall off, and manual limiting is required during the manual assembly process. However, as the structure is gradually miniaturized, manual limiting becomes more difficult to achieve, which leads to inconvenience in assembly. Summary of the invention

[0006] The purpose of the present invention is to provide a miniature proportional valve to solve the problems in the prior art that, under the requirements of miniaturized design, the proportional valve has too many parts, resulting in complicated assembly, relatively low control accuracy and great maintenance difficulty.

[0007] The technical solution of the present invention is: a micro proportional valve, comprising:

[0008] A valve body, the valve body comprising a shell and a valve seat, the valve seat is provided with a fluid inlet and a fluid outlet, and a fluid channel is provided between the fluid inlet and the fluid outlet;

[0009] A stationary armature and a coil are built into the valve body, and the coil is arranged around the stationary armature;

[0010] A valve core, wherein the valve core is coaxially arranged with the static armature, a portion of the valve core is limited between the spring piece and the valve seat, and the valve core moves axially under the action of the electromagnetic force to open and close the fluid channel;

[0011] The positioning member has a plurality of positioning surfaces and is configured to synchronously realize the positioning of the valve body, the coil, the static armature, the valve core and the spring.

[0012] The positioning member is integrally formed and includes a first positioning portion and a second positioning portion having different inner and outer diameters;

[0013] An inner step surface is formed between the inner wall of the first positioning portion and the inner wall of the second positioning portion, and an outer step surface is formed between the outer wall of the first positioning portion and the outer wall of the second positioning portion; the inner step surface, the outer step surface, the inner wall and the outer wall of the first positioning portion, and the inner wall and the outer wall of the second positioning portion are configured to form the positioning surface;

[0014] The inner wall and inner step surface of the first positioning portion are used to position the static armature, the outer part and outer step surface of the first positioning portion are used to position the coil, the inner wall of the second positioning portion is used to position the valve core, the outer wall of the second positioning portion is used to position the shell, and the side of the second positioning portion away from the first positioning portion is used to position the valve core and the spring.

[0015] The end surface of the second positioning portion on one side away from the first positioning portion has a first recessed surface and a second recessed surface formed inwardly;

[0016] The elastic sheet is supported by the valve core and abuts against the first recessed surface, and a space for the elastic sheet to deform is formed between the first recessed surface and the second recessed surface.

[0017] Preferably, the valve core includes a first core body and a second core body which are coaxially arranged; the first core body is inserted into the second positioning portion, and the second core body is limited between the inner end of the fluid outlet and the spring sheet.

[0018] Preferably, one end of the static armature that abuts against the inner step surface is concave to form an accommodating space, and the valve core is inserted into the second positioning portion and extends into the accommodating space. Due to the limiting effect of the inner wall of the second positioning portion, part of the valve core is always suspended in the accommodating space.

[0019] Preferably, the shell is threadedly connected to the valve seat, wherein an inner wall of one end of the shell close to the valve seat and an outer wall of the valve seat are both threaded.

[0020] Preferably, the stationary armature and the housing are constructed as an integral structure.

[0021] Preferably, a hollow area is provided on the shell to facilitate heat dissipation.

[0022] Preferably, a first seal is provided between the stationary armature and the inner wall of the first positioning portion, a second seal is provided between the housing and the outer wall of the second positioning portion, and a third seal is provided between the valve seat and the housing.

[0023] Preferably, a first sealing cavity for accommodating the first sealing member is formed at the outer wall of the static armature;

[0024] A second sealing cavity for accommodating a second sealing member is formed at the outer wall of the second positioning portion;

[0025] An outer vertex angle of the inner end of the valve seat forms an inclined surface, and a third sealing cavity for accommodating a third sealing member is formed between the inclined surface, the inner wall of the shell body and the end surface of the positioning member.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] (1) The present invention only uses positioning parts to simultaneously realize the positioning of core components including the valve body, coil, static armature, valve core and spring. The entire micro proportional valve consists of fewer parts, with higher spatial integration, which can fully meet the design requirements of miniaturization. At the same time, based on the role of the positioning parts, the control accuracy problem of the traditional structure due to a large number of matching tolerance problems is reduced, and the overall performance is better.

[0028] (2) An accommodating space is provided on the stationary armature to accommodate the end of the valve core, which further reduces the size of the overall structure in terms of space. Since the valve core is always guided by the positioning member, the valve core is always suspended in the accommodating space under different working conditions.

[0029] (3) The miniaturization of the structure leads to greater limitations. However, the present application reduces the difficulty of assembly based on the setting of the positioning parts. Except for the threaded connection between the shell and the valve seat, the remaining parts of the overall structure are efficiently positioned in the valve body through the positioning parts. During the assembly process, all the loose parts are placed upside down in the shell, and finally the valve seat and the shell are locked together to form a shape.

[0030] (4) In the application scenario, the miniature proportional valve itself has low power and can provide small power. The positioning parts are made of self-lubricating materials with a small friction coefficient. While positioning, it does not affect the movement of moving parts. The overall structural performance is excellent.

[0031] (5) All seals are completely isolated from the fluid channel, effectively ensuring the purity of the fluid channel and preventing the seal from evaporating substances into the fluid channel due to heat in the application scenario. At the same time, the third seal arranged between the valve seat and the shell forms a third sealing cavity by forming an inclined surface at the outer top corner of the inner end of the valve seat, avoiding the opening of a chamber structure at other positions of the valve seat to affect the connection stability between the valve seat and the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0033] Figure 1 An exploded view of a miniature proportional valve according to the present invention;

[0034] Figure 2 A cross-sectional view of a micro proportional valve according to the present invention;

[0035] Figure 3 is a cross-sectional view of the positioning member of the present invention;

[0036] Figure 4 A schematic diagram showing the inner and outer diameters of the first positioning portion and the second positioning portion of the positioning member of the present invention;

[0037] Figure 5 It is a schematic diagram of the structural state of a micro proportional valve according to the present invention in the first step of assembly;

[0038] Figure 6 It is a schematic diagram of a state in which a positioning piece is installed during assembly of a micro proportional valve according to the present invention;

[0039] Figure 7 It is a schematic diagram of the state of installing the valve core and the spring piece during the assembly of the micro proportional valve of the present invention;

[0040] Figure 8 This is a schematic diagram of the state of a micro proportional valve described in the present invention after assembly.

[0041] Among them: 1. Valve body;

[0042] 11. housing, 12. valve seat, 13. hollow area, 14. fluid inlet, 15. fluid outlet, 16. fluid channel, 17. cut-off surface;

[0043] 2. static armature, 21. accommodation space;

[0044] 3. Coil, 31. Rubber pad;

[0045] 4. Valve core;

[0046] 41, a first core, 42, a second core;

[0047] 5. Shrapnel;

[0048] 6. Positioning parts;

[0049] 61, first positioning portion, 62, second positioning portion, 63, inner step surface, 64, outer step surface, 65, first recessed surface, 66, second recessed surface;

[0050] 71. First sealing member, 711. First sealing cavity, 72. Second sealing member, 721. Second sealing cavity, 73. Third sealing member, 731. Third sealing cavity, 74. Fourth sealing member. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with specific embodiments:

[0052] like Figure 1 , Figure 2 As shown, a miniature proportional valve includes a valve body 1, a stationary armature 2, a coil 3, a valve core 4, a spring 5 and a positioning member 6; wherein the valve body 1, the stationary armature 2, the coil 3, the valve core 4, the spring 5 are core components of the miniature proportional valve, and the positioning member 6 is used to position all core components.

[0053] Specifically, Figure 2 As shown, the valve body 1 includes a shell 11 and a valve seat 12 .

[0054] The housing 11 is a cylindrical structure with an open lower end, and a plurality of hollow areas 13 are provided on the outer wall to facilitate heat dissipation inside the housing 11 in a working scenario. In order to meet the connection between the housing 11 and the valve seat 12, the inner wall of the open end of the housing 11 is threaded.

[0055] The valve seat 12 is arranged at the open end of the housing 11 and serves as a valve cover. The outer wall is threaded and is used to achieve threaded connection with the housing 11, and then the remaining components are accommodated in the space formed by the combination of the housing 11 and the valve seat 12. The valve seat 12 is provided with a fluid inlet 14 and a fluid outlet 15, and a fluid channel 16 is provided between the fluid inlet 14 and the fluid outlet 15. In this embodiment, the axial directions of the fluid inlet 14 and the fluid outlet 15 are perpendicular to the end face of the valve seat 12, and the inner end of the fluid outlet 15 is defined as Figure 2 The upper end of the fluid outlet 15 is shown in the figure. In this embodiment, the inner end of the fluid outlet 15 is protruding and forms a cut-off surface 17.

[0056] The stationary armature 2 and the coil 3 are built into the valve body 1, and the coil 3 is arranged around the stationary armature 2. Figure 2As shown, in this embodiment, the static armature 2 and the housing 11 are constructed as an integral structure, and the structure manufacturing and assembly are simpler. The valve core 4 is coaxially arranged with the static armature 2, and part of the valve core 4 is limited between the spring 5 and the valve seat 12; when working, when the electrical signal is transmitted to the coil 3, a magnetic field is generated in the coil 3, and the valve core 4 moves axially under the action of the electromagnetic force, opening and closing the fluid channel 16.

[0057] The coil 3, valve core 4 and spring 5 can be stably installed in the valve body 1 only based on the positioning member 6. Therefore, the positioning member 6 has multiple positioning surfaces and is configured to simultaneously realize the positioning of the valve body 1, coil 3, stationary armature 2, valve core 4 and spring 5.

[0058] Specifically, Figure 1 , Figure 3 As shown, the positioning member 6 is integrally formed and includes a first positioning portion 61 and a second positioning portion 62 having different inner and outer diameters. Figure 4 As shown, the inner diameter of the first positioning portion 61 is d1, and the outer diameter of the first positioning portion 61 is d2; the inner diameter of the second positioning portion 62 is d3, and the outer diameter of the second positioning portion 62 is d4.

[0059] Recombination Figure 3 As shown, an inner step surface 63 is formed between the inner wall of the first positioning portion 61 and the inner wall of the second positioning portion 62, and an outer step surface 64 is formed between the outer wall of the first positioning portion 61 and the outer wall of the second positioning portion 62; the end surface of the second positioning portion 62 away from the first positioning portion 61 has a first indented surface 65 and a second indented surface 66 formed by indentation. In the present application, the inner step surface 63, the outer step surface 64, the inner wall and the outer wall of the first positioning portion 61, the inner wall and the outer wall of the second positioning portion 62, the end surface of the second positioning portion 62 away from the first positioning portion 61, and the first indented surface 65 are all constructed to form positioning surfaces.

[0060] like Figure 2 As shown, the inner wall of the first positioning part 61 and the inner step surface 63 are used to position the stationary armature 2, and the outer wall of the second positioning part 62 is used to position the housing 11. Since the stationary armature 2 and the housing 11 are integrally formed, it can be understood that the positioning member 6 and the stationary armature 2 / housing 11 play a role in mutual positioning. The outside of the first positioning part 61 and the outer step surface 64 are used to position the coil 3, that is, the first positioning part 61 is inserted between the stationary armature 2 and the coil 3, and a rubber pad 31 is provided between the end of the coil 3 away from the outer step surface 64 and the housing 11. The inner wall of the second positioning part 62 is used to position the valve core 4, and the side of the second positioning part 62 away from the first positioning part 61 is used to position the valve core 4 and the spring 5.

[0061] As for the installation of the valve core 4 and the spring 5, the more specific ones are as follows:

[0062] Combination Figure 1As shown, the valve core 4 includes a first core body 41 and a second core body 42 which are coaxially arranged; the first core body 41 is inserted into the second positioning portion 62, the outer diameter of the second core body 42 is larger than the outer diameter of the first core body 41, the spring piece 5 is supported by the second core body 42 and abuts against the first recessed surface 65, and the second core body 42 itself is supported by the cut-off surface 17; further, based on the supporting effect of the second core body 42 on the spring piece 5, the second core body 42 itself is also limited between the inner end (cut-off surface 17) of the fluid outlet 15 and the spring piece 5. In the working scene, a space for the spring piece 5 to deform is formed between the first recessed surface 65 and the second recessed surface 66. In order to avoid long-term contact and wear between the second core body 42 and the cut-off surface 17, a flexible material can be embedded in the second core body 42 to ensure the sealing of the micro proportional valve in the off state.

[0063] In order to further reduce the spatial size of the overall structure, the end of the stationary armature 2 that abuts against the inner step surface 63 is recessed to form an accommodating space 21. The valve core 4 is inserted into the second positioning portion 62 and extends into the accommodating space 21. Under the action of the inner wall of the second positioning portion 62, part of the valve core 4 is always suspended in the accommodating space 21.

[0064] It should be noted that the positioning function of the positioning member 6 on the valve core 4 is radial positioning, and does not affect the axial movement of the valve core 4 itself. To ensure the stability of the guide, the gap between the positioning member 6 and the valve core 4 will be relatively small; and because the power of the micro proportional valve is relatively small, its power is also very small. If the positioning member 6 is made of metal material, the friction between the positioning member 6 and the valve core 4 will be too large, seriously affecting the performance of the structure. Therefore, in this embodiment, the positioning member 6 is made of POM material, which has self-lubricating properties and a small friction coefficient.

[0065] In order to further ensure the sealing of the overall structure, a first sealing member 71 is provided between the stationary armature 2 and the inner wall of the first positioning portion 61, a second sealing member 72 is provided between the housing 11 and the outer wall of the second positioning portion 62, and a third sealing member 73 is provided between the valve seat 12 and the housing 11. A first sealing cavity 711 for accommodating the first sealing member 71 is formed at the outer wall of the stationary armature 2, and a second sealing cavity 721 for accommodating the second sealing member 72 is formed at the outer wall of the second positioning portion 62; an inclined surface is formed at the outer top corner of the inner end of the valve seat 12, and a third sealing cavity 731 for accommodating the third sealing member 73 is formed between the inclined surface and the inner wall of the housing 11 and the end face of the positioning member 6. Of course, since both the fluid inlet 14 and the fluid outlet 15 need to be connected to external equipment, a fourth sealing member 74 is also provided at the fluid inlet 14 and the fluid outlet 15.

[0066] In this embodiment, all seals are built-in, but the seals are still isolated from the fluid channel 16, which can effectively ensure the purity of the fluid channel 16 and prevent the seals from evaporating substances into the fluid channel 16 due to heat.

[0067] Based on the disclosure of the above structure, the specification of a micro proportional valve disclosed by the present invention is basically controlled at 15mm·15mm in actual application scenarios, that is, the outer diameter and height of the cylindrical proportional valve are both maintained at about 15mm. Based on its miniaturization, it has more limitations in structural design. As for the third seal 73 between the valve seat 12 and the housing 11, based on the size limitation of the structure and the performance requirements, an inclined surface is formed at the outer top angle of the inner end of the valve seat 12, and a third sealing cavity 731 for accommodating the third seal 73 is formed. If the third seal 73 is set at the middle position where the valve body 1 and the housing 11 fit together, the corresponding back-cut groove of the threaded connection must be enlarged, the number of threads of the thread will be reduced, and then the phenomenon of slipping and locking will occur when the size of the overall structure remains unchanged. If the number of threads remains unchanged in the case of the back-cut groove, the length of the overall structure along the axial direction will be increased. Therefore, the reasonable position layout of the third seal 73 of the present application also makes full use of the space in the valve body 1.

[0068] Therefore, based on the setting of the positioning part 6, the present application simultaneously realizes the positioning of the core components including the valve body 1, the coil 3, the static armature 2, the valve core 4 and the spring 5. The entire miniature proportional valve has fewer parts and a higher spatial integration, which can fully meet the miniaturized design requirements. At the same time, based on the role of the positioning part 6, the control accuracy problem of the traditional structure affected by a large number of fitting tolerance problems is reduced, and the overall performance is better.

[0069] Specifically, a relative positioning relationship is formed between the positioning member 6 and the valve body 1 , and the positioning member 6 satisfies the radial and axial limitation of the coil 3 and the radial limitation of the valve core 4 , while the combination of the valve core 4 and the positioning member 6 satisfies the axial and radial limitation of the spring 5 .

[0070] Because only a single positioning member 6 is used to achieve the positioning of the overall structure, compared with the traditional proportional valve, the present invention can greatly reduce the size of the overall structure while greatly reducing the number of parts. In the specific structural design, by opening a receiving space 21 in the static armature 2, part of the valve core 4 is accommodated in the receiving space 21, which can reduce the axial length of the static armature 2 and the valve core 4 to a certain extent. Based on the setting of the inclined surface on the valve seat 12, a third sealing cavity 731 is formed between the valve seat 12 and the housing 11 to accommodate the third sealing member 73, thereby simultaneously ensuring the requirements of small volume, sealing and locking degree.

[0071] Based on the disclosure of various components, the assembly difficulty of the present application is also reduced. The specific assembly method is as follows:

[0072] a. Figure 5As shown, the housing 11 is inverted with the opening facing upward, and the coil 3 is placed in the housing 11. The inner diameter of the coil 3 is larger than the outer diameter of the stationary armature 2. Since the housing 11 and the stationary armature 2 are integrally formed, the coil 3 is directly sleeved on the peripheral side of the stationary armature 2 after being placed.

[0073] b. Figure 6 As shown, a first sealing member 71 of a corresponding size is sleeved at the first sealing cavity 711 of the outer wall of the stationary armature 2, and a second sealing member 72 of a corresponding size is sleeved at the second sealing cavity 721 of the outer wall of the positioning member 6, and then the first positioning portion 61 of the positioning member 6 is placed downward into the housing 11, so that the first positioning portion 61 is inserted between the stationary armature 2 and the coil 3, and at this time, the first recessed surface 65 and the second recessed surface 66 face upward; based on the placement of the positioning member 6, the relative positioning of the coil 3, the stationary armature 2 / housing 11, and the positioning member 6 in the radial direction is synchronously achieved;

[0074] c. Figure 7 As shown, the spring piece 5 is sleeved on the first core body 41, and the first core body 41 is inserted downward into the positioning member 6. At this time, the spring piece 5 is mounted on the first recessed surface 65, and the end of the first core body 41 away from the second core body 42 enters the accommodating space 21; at this time, the positioning member 6 realizes the radial positioning of the valve core 4, and because the spring piece 5 is sleeved on the first core body 41, the spring piece 5 also realizes the radial limitation; thereafter, the third sealing member 73 is placed in the housing 11, so that the third sealing member 73 is placed on the positioning member 6;

[0075] d. Figure 8 As shown, the valve seat 12 is screwed onto the housing 11 to achieve the threaded connection between the valve seat 12 and the housing 11 until the end face of the valve seat 12 abuts against the end face of the positioning member 6, and the cut-off surface 17 also abuts against the end face of the valve core 4; based on the connection between the valve seat 12 and the housing 11, the axial limit of the coil 3, the positioning member 6, the valve core 4, and the spring 5 is completed. Before and after the valve seat 12 is assembled, the fourth sealing member 74 needs to be installed at the fluid inlet 14 and the fluid outlet 15 respectively. At this point, the assembly and molding of the entire micro proportional valve is completed.

[0076] Therefore, during the assembly process, before the valve seat 12 is installed in the shell 11, it is only necessary to place all the scattered parts in the shell 11 in sequence, and the positioning member 6 can realize the positioning of all the parts until the valve seat 12 is finally installed. The assembly of the overall structure is completed by the fixed connection between the valve seat 12 and the shell 11; the overall structure is small, but easy and quick to assemble.

[0077] During operation, by connecting the coil 3 to electricity, a magnetic field is generated in the coil 3, and the valve core 4 moves axially under the action of the electromagnetic force. Figure 2Taking the direction shown as an example, the valve core 4 will overcome the force of the spring 5 and move upward, at which time a gap is formed between the valve core 4 and the cut-off surface 17, and the fluid can enter the fluid channel 16 from the fluid inlet 14 and finally flow out from the fluid outlet 15. When the coil 3 is not powered, the valve core 4 is always pressed against the cut-off surface 17 by the spring 5, keeping the fluid inlet 14 and the fluid outlet 15 disconnected.

[0078] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the scope of protection of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A micro proportional valve, characterized in that: include: A valve body (1), the valve body (1) comprising a shell (11) and a valve seat (12), the valve seat (12) being provided with a fluid inlet (14) and a fluid outlet (15), and a fluid channel (16) being provided between the fluid inlet (14) and the fluid outlet (15); A stationary armature (2) and a coil (3) are built into the valve body (1), and the coil (3) is arranged around the stationary armature (2); A valve core (4), the valve core (4) being coaxially arranged with the stationary armature (2), a portion of the valve core (4) being limited between the spring (5) and the valve seat (12), and the valve core (4) moving axially under the action of electromagnetic force, thereby opening and closing the fluid passage (16); A positioning member (6), the positioning member (6) having a plurality of positioning surfaces and being configured to synchronously realize the positioning of the valve body (1), the coil (3), the stationary armature (2), the valve core (4) and the spring (5); The positioning member (6) is integrally formed and comprises a first positioning portion (61) and a second positioning portion (62) having different inner and outer diameters; An inner step surface (63) is formed between the inner wall of the first positioning portion (61) and the inner wall of the second positioning portion (62), and an outer step surface (64) is formed between the outer wall of the first positioning portion (61) and the outer wall of the second positioning portion (62); the inner step surface (63), the outer step surface (64), the inner wall and the outer wall of the first positioning portion (61), and the inner wall and the outer wall of the second positioning portion (62) are constructed to form the positioning surface; The inner wall and the inner step surface (63) of the first positioning portion (61) are used to position the stationary armature (2); the outer portion and the outer step surface (64) of the first positioning portion (61) are used to position the coil (3); the inner wall of the second positioning portion (62) is used to position the valve core (4); the outer wall of the second positioning portion (62) is used to position the housing (11); and a side of the second positioning portion (62) away from the first positioning portion (61) is used to position the valve core (4) and the spring sheet (5); The end surface of one side of the second positioning portion (62) away from the first positioning portion (61) comprises a first recessed surface (65) and a second recessed surface (66) formed inwardly; The spring sheet (5) is supported by the valve core (4) and abuts against the first recessed surface (65), and a space is formed between the first recessed surface (65) and the second recessed surface (66) for the spring sheet (5) to deform.

2. A micro proportional valve according to claim 1, characterized in that: The valve core (4) comprises a first core body (41) and a second core body (42) which are coaxially arranged; the first core body (41) is inserted into the second positioning portion (62), and the second core body (42) is located between the inner end of the fluid outlet (15) and the spring sheet (5).

3. A micro proportional valve according to claim 1, characterized in that: One end of the stationary armature (2) abutting against the inner step surface (63) is concave to form an accommodating space (21); the valve core (4) is inserted into the second positioning portion (62) and extends into the accommodating space (21); and due to the limiting effect of the inner wall of the second positioning portion (62), a portion of the valve core (4) is always suspended in the accommodating space (21).

4. A micro proportional valve according to claim 1, characterized in that: The shell (11) is threadedly connected to the valve seat (12), wherein an inner wall of an end of the shell (11) close to the valve seat (12) and an outer wall of the valve seat (12) are both threaded.

5. A micro proportional valve according to claim 1, characterized in that: The stationary armature (2) and the housing (11) are constructed as an integral structure.

6. A micro proportional valve according to claim 1, characterized in that: The housing (11) is provided with a hollow area (13) for facilitating heat dissipation.

7. A micro proportional valve according to claim 1, characterized in that: A first sealing member (71) is provided between the stationary armature (2) and the inner wall of the first positioning portion (61), a second sealing member (72) is provided between the housing (11) and the outer wall of the second positioning portion (62), and a third sealing member (73) is provided between the valve seat (12) and the housing (11).

8. A micro proportional valve according to claim 7, characterized in that: A first sealing cavity (711) for accommodating a first sealing member (71) is formed on the outer wall of the stationary armature (2); A second sealing cavity (721) for accommodating the second sealing member (72) is formed on the outer wall of the second positioning portion (62); An inclined surface is formed at the outer top corner of the inner end of the valve seat (12), and a third sealing cavity (731) for accommodating a third sealing member (73) is formed between the inclined surface, the inner wall of the housing (11) and the end surface of the positioning member (6).

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