Electromagnetic coil assembly and normally open solenoid valve

Abstract

This application discloses an electromagnetic coil assembly and a normally open solenoid valve. The electromagnetic coil assembly includes a coil frame, a coil winding, a connecting terminal, a lead wire, and a plastic encapsulation shell. The coil frame has a cylindrical body and end caps at both ends. The coil winding is wound around the cylindrical body. The connecting terminal is fixed to the side of the end cap and electrically connected to the lead wire of the coil winding. One end of the lead wire is connected to the connecting terminal, and the other end extends along the outer end face of the end cap and crosses the edge of the end cap away from the connecting terminal to form an exposed section. The plastic encapsulation shell covers the above components and exposes the exposed section of the lead wire. By extending the lead wire arrangement path, increasing the distance between the welding point and the lead wire end, and increasing the plastic encapsulation thickness, the risk of moisture intrusion is reduced, corrosion and poor contact at the welding point are avoided, and the reliability and service life of the electromagnetic coil assembly are improved.

Description

Technical Field

[0001] This application relates to solenoid valves, and more particularly to an electromagnetic coil assembly and a normally open solenoid valve. Background Technology

[0002] Solenoid valves are actuators used for fluid control, specifically for the on / off switching, diversion, and pressure regulation of gas or liquid media in industrial automation systems. The coil assembly generates a driving magnetic field to control the movement of the valve core. A common coil assembly includes a coil frame, a coil winding wound on the frame, connecting terminals electrically connected to the coil winding, leads welded to the connecting terminals, and a plastic-encapsulated housing covering the entire structure. The applicant has discovered that in this type of coil assembly, because the distance between the welding point of the connecting terminal and the lead and the lead outlet of the plastic-encapsulated housing is relatively short, and the plastic coating thickness at the welding point is also small, frequent pulling of the lead can easily create gaps at the plastic-encapsulated lead outlet. These gaps allow moisture to enter, leading to rust and poor contact at the welding point over time, ultimately causing coil assembly failure and affecting the overall reliability and service life of the solenoid valve. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this application provides an electromagnetic coil assembly and a normally open solenoid valve.

[0004] To achieve the above objectives, the technical solution of this application is as follows: An electromagnetic coil assembly includes: a coil frame, comprising a cylindrical body and end caps located at both ends of the cylindrical body; a coil winding, wound around the outer periphery of the cylindrical body, and having lead-out ends; connecting terminals, electrically connected to the lead-out ends of the coil winding, and fixed to one side of the end cap; a lead wire, one end of which is electrically connected to the connecting terminal, and the other end extending along the outer end face of the end cap to an edge region beyond the end cap and away from the connecting terminal, forming an exposed section; and a plastic-encapsulated shell, covering the coil frame, coil winding, connecting terminals, and lead wire, and exposing the exposed section of the lead wire.

[0005] Furthermore, the lead wire and the connecting terminal are connected by welding.

[0006] Furthermore, the outer end face of the end cap is provided with a wire-passing groove for the lead wire to pass through, and a gap is formed between the wire-passing groove and the lead wire.

[0007] Furthermore, one side of the end cap is provided with a slot for inserting a fixed connection terminal, the slot opening facing the outer end face of the end cap and forming a height difference with the wire passage groove.

[0008] Furthermore, the connection terminal includes a insert body, a first connection part, and a second connection part. The insert body is inserted into the slot along the side of the end cover. The first connection part is located outside the slot and is used for electrical connection with the lead end of the coil winding. The second connection part is located outside the slot and is used for electrical connection with the lead wire.

[0009] Furthermore, the insert body has several tooth-shaped protrusions on both sides, which form an interference fit with the inner wall of the slot.

[0010] Furthermore, at least two protrusions arranged along the insertion direction are provided on both sides of the insert body, and a channel is provided between the slot and the wire guide groove in the area corresponding to the insert body to connect the two.

[0011] Furthermore, the wire-passing groove includes an arc segment surrounding the outer periphery of the cylindrical body and a straight segment extending outward from the end of the arc segment away from the connecting terminal; two leads are provided, and a wire-passing groove is provided for each of the two leads, and the two wire-passing grooves are provided on one end cap. The arc segments of the two wire-passing grooves are located on both sides of the cylindrical body and are symmetrically distributed relative to the center line of the cylindrical body. The straight segments of the two wire-passing grooves are arranged adjacent to each other at a certain distance and are parallel.

[0012] Furthermore, a normally open solenoid valve includes: an electromagnetic coil assembly as described in any of the above claims; a valve body having an inlet, an outlet, and a valve port connecting the inlet and outlet, wherein the electromagnetic coil assembly is fixedly connected to the valve body; a stationary iron core disposed within the central cavity of the cylindrical body and fixedly connected relative to the valve body to form a valve cavity, wherein the stationary iron core has an axially penetrating through hole at its center; and a valve core assembly including a movable rod, a transmission rod, a valve core, and a return spring, wherein the movable rod is located within the central cavity of the cylindrical body and at the end of the stationary iron core furthest from the valve body, the transmission rod passes through the through hole of the stationary iron core and its two ends are respectively engaged with the movable rod and the valve core, the valve core is located within the valve cavity and can slide axially, one end of which is fixedly connected to the transmission rod, and the other end is provided with a sealing plug for opening and closing the valve port, and the return spring acts on the valve core to form a preload force toward the stationary iron core, so that the valve core remains in an open state separated from the valve port under normal conditions.

[0013] Furthermore, a first sealing element is provided between the stationary iron core and the inner wall of the valve body, and a second sealing element is provided between the stationary iron core and the inner wall of the cylindrical body. Both the first sealing element and the second sealing element are annular elastic bodies.

[0014] The beneficial effects of this application are as follows: The electromagnetic coil assembly of this application, by electrically connecting one end of the lead wire to the connecting terminal and extending the other end along the outer end face of the end cover to the edge area far away from the connecting terminal beyond the end cover, forms an exposed section. This significantly increases the distance between the connection part (such as the welding part) between the lead wire and the connecting terminal and the wire outlet part of the plastic casing, thereby increasing the plastic coating thickness of the plastic casing at this part. When the lead wire is frequently pulled, the probability of gaps occurring at the wire outlet end of the plastic casing is greatly reduced. Even if a small gap occurs, due to the large distance between the connection part and the wire outlet part, moisture is unlikely to reach the connection part, thus effectively avoiding the problems of rust and poor contact caused by moisture intrusion at the connection part. This improves the stability and service life of the coil assembly, thereby ensuring the overall reliability of the solenoid valve using this coil assembly. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0016] Figure 1 This is a schematic diagram of the structure of the coil assembly provided in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the coil assembly after the plastic encapsulation shell is hidden, as provided in the embodiments of this application; Figure 3 This is a schematic diagram of the coil frame provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of the connection terminal provided in the embodiment of this application; Figure 5 The following are cross-sectional views of the coil assembly provided in the embodiments of this application. (A) and (B) are cross-sections at two different locations. Figure 6 for Figure 3 Enlarged schematic diagram of section I; Figure 7 for Figure 5 (B) Enlarged schematic diagram of part I; Figure 8 This is a schematic diagram of the overall structure of the solenoid valve provided in the embodiments of this application; Figure 9 An exploded view of a solenoid valve provided for an embodiment of this application; Figure 10 A cross-sectional view of a solenoid valve provided in an embodiment of this application; Figure 11 for Figure 10Enlarged schematic diagram of section I; Figure 12 This is a schematic diagram of the valve core structure; In the diagram, 100-coil frame, 110-cylindrical body, 120-end cap, 121-wire groove, 122-slot, 123-channel, 200-molded shell, 210-molding material, 300-connecting terminal, 310-insertion body, 311-protrusion, 320-first connecting part, 330-second connecting part, 400-lead wire, 500-valve body, 510-inlet, 520-outlet, 530-valve port, 540-spacer ring, 550-coil bracket, 600-stationary iron core, 610-first seal, 620-second seal, 630-limiting protrusion ring, 710-moving rod, 720-transmission rod, 730-valve core, 731-sealing plug, 732-insertion hole, 733-groove, 734-connecting block, 740-reset spring. Detailed Implementation

[0017] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0019] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0020] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In this application, "and / or" is merely a way of describing the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0023] It should be noted that in this application, the words "in some embodiments," "exemplarily," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "in some embodiments," "exemplarily," or "for example" should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of words such as "in some embodiments," "exemplarily," and "for example" is intended to present related concepts in a specific manner, meaning that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of this application. The appearance of the above words in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0024] To address the problems in related technologies, embodiments of this application provide an electromagnetic coil assembly and a normally open solenoid valve, such as... Figure 1 , Figure 2 As shown, it includes: a coil frame 100, including a cylindrical body 110 and end caps 120 located at both ends of the cylindrical body 110; a coil winding, wound around the outer periphery of the cylindrical body 110, and having lead-out ends; connecting terminals 300, which are electrically connected to the lead-out ends of the coil winding and fixed to one side of the end cap 120; a lead wire 400, one end of which is electrically connected to the connecting terminal 300, and the other end extends along the outer end face of the end cap 120 to the edge area of ​​the end cap 120 away from the connecting terminal 300, forming an exposed section; and a plastic encapsulation shell 200, which covers the coil frame 100, the coil winding, the connecting terminal 300 and the lead wire 400, and exposes the exposed section of the lead wire 400.

[0025] In this embodiment, the coil frame 100 serves as the core support structure, with its cylindrical body 110 used for winding to form a coil winding. The end caps 120 at both ends effectively limit the axial ends of the coil winding. The connecting terminal 300 acts as an intermediate bridge for electrical connection, connecting one end to the lead-out end of the coil winding and the other end to the lead wire 400, responsible for transmitting electrical energy from the external circuit to the coil winding. One end of the lead wire 400 is electrically connected to the connecting terminal 300, while the other end extends along the outer end face of the end cap 120 and crosses the edge area of ​​the end cap 120 away from the connecting terminal 300, forming an exposed section. This exposed section is used for plugging or soldering with the external circuit. The plastic-encapsulated shell 200 is formed from a thermosetting plastic with good insulation properties through a molding process. It tightly covers the main body of the coil frame 100, coil winding, connecting terminal 300, and lead wire 400, exposing only the exposed section of the lead wire 400, providing good insulation protection for the internal electrical components.

[0026] Compared to existing technologies, the core improvement of this embodiment is that by extending one end of the lead 400 beyond the edge region of the end cap 120 and away from the connecting terminal 300, the distance between the welding point of the lead 400 and the connecting terminal 300 and the lead outlet of the plastic casing 200 is significantly increased, thereby increasing the plastic coating thickness of the plastic casing 200 on the lead 400. Even when the lead 400 is frequently pulled, the probability of gaps occurring at the lead outlet of the plastic casing 200 is significantly reduced. Even if a small gap occurs, moisture must travel a longer path to reach the welding point, effectively preventing the welding point from rusting and poor contact due to moisture intrusion, thus improving the long-term operational stability and service life of the electromagnetic coil assembly.

[0027] Optionally, in some embodiments, the lead wire 400 and the connecting terminal 300 are connected by welding. This embodiment achieves a fixed connection between the lead wire 400 and the connecting terminal 300 through welding, which not only ensures electrical continuity between the two but also enhances the stability of the mechanical structure.

[0028] Optionally, in some embodiments, the outer end face of the end cap 120 is provided with a wire-passing groove 121 for the lead wire 400 to pass through, and a gap is formed between the wire-passing groove 121 and the lead wire 400. In this embodiment, the wire-passing groove 121 is arc-shaped, and its groove size is slightly larger than the outer diameter of the lead wire 400, so that the lead wire 400 can be smoothly embedded in the groove. The gap reserved between the inner wall of the groove and the outer periphery of the lead wire 400 is used for the plastic encapsulation shell 200 to fully fill and solidify during the molding process to form a plastic encapsulation material 210. The plastic encapsulation material 210 forms a dense covering structure on the outside of the lead wire, thereby improving the sealing performance and tensile strength of the joint area between the lead wire 400 and the end cap 120.

[0029] Optionally, in some embodiments, a slot 122 for inserting and fixing the connecting terminal 300 is provided on one side of the end cover 120. The opening of the slot 122 faces the outer end face of the end cover 120 and forms a height difference with the wire-passing groove 121. In this embodiment, the slot 122 forms a blind groove on the side of the end cover 120 to achieve the insertion and fixing of the connecting terminal 300. The height difference between the opening of the slot 122 and the wire-passing groove 121 spatially offsets the installation position of the connecting terminal 300 from the arrangement position of the lead wire 400, avoiding interference between the connecting terminal 300 and the lead wire 400 during installation and improving assembly efficiency.

[0030] Alternatively, in some embodiments, such as Figure 4 As shown, the connection terminal 300 includes a insert body 310, a first connecting portion 320, and a second connecting portion 330. The insert body 310 is inserted into the slot 122 along the side of the end cover 120. The first connecting portion 320 is located outside the slot and is used for electrical connection with the lead end of the coil winding. The second connecting portion 330 is located outside the slot 122 and is used for electrical connection with the lead wire 400. In this embodiment, the insert body 310, the first connecting portion 320, and the second connecting portion 330 are integrally connected. The insert body 310 and the second connecting portion 330 are connected, and the whole has a sheet-like structure. The first connecting portion 320 is a metal pin formed by extending outward from the side of the second connecting portion 330.

[0031] Optionally, in some embodiments, the insert body 310 has a plurality of toothed protrusions 311 on both sides, and the protrusions 311 form an interference fit with the inner wall of the slot 122. In this embodiment, the protrusions 311 are triangular toothed and evenly distributed along the length of the insert body 310. Their height is slightly greater than the fit gap between the slot 122 and the insert body 310. When the insert body 310 is inserted into the slot 122, the toothed protrusions 311 undergo elastic deformation, forming a tight interference fit with the inner wall of the slot 122. As an alternative embodiment, those skilled in the art can also set the protrusions 311 to be semi-circular or trapezoidal, as long as an interference fit with the inner wall of the slot 122 can be achieved. This effectively prevents the connecting terminal 300 from coming out of the slot 122 due to vibration or external force during assembly, ensuring assembly efficiency.

[0032] Optionally, in some embodiments, at least two protrusions 311 arranged along the insertion direction are provided on both sides of the insert body 310, and a channel 123 is provided between the slot 122 and the wire guide groove 121 in the corresponding area of ​​the insert body 310 to connect the two. The channel 123 provides that during the molding process, the plastic encapsulation shell 200 passes through and penetrates the gap between the two sides of the insert body 310 and the inner wall of the slot 122, such as... Figure 7As shown, the gap between the two sides of the insert body 310 and the inner wall of the slot 122 is fully filled and cured to form a molding compound 210. The molding compound 210 between the adjacent protrusions 311 and the inner wall of the slot 122 provides a more effective fixing effect on the insert body 310.

[0033] Alternatively, in some embodiments, such as Figure 3 As shown, the wire guide groove 121 includes an arc segment surrounding the outer periphery of the cylindrical body 110 and a straight segment extending outward from the end of the arc segment away from the connecting terminal 300. Two leads 400 are provided, and a wire guide groove 121 is provided for each of the two leads 400. The two wire guide grooves 121 are disposed on an end cap 120. The arc segments of the two wire guide grooves 121 are located on both sides of the cylindrical body 110 and are symmetrically distributed relative to the center line of the cylindrical body 110. The straight segments of the two wire guide grooves 121 are adjacent to each other at a certain distance and are parallel. The wire guide groove 121 adopts a structure combining arc segments and straight segments. The arc segments can adapt to the circular shape of the cylindrical body 110, allowing the leads 400 to smoothly transition at bends, while the straight segments facilitate the neat outward extension of the leads 400, making it convenient for molding and external wiring. Two wire-passing grooves 121 are symmetrically arranged on the same end cover 120, which can make the routing path length of the two leads 400 basically the same. At the same time, the straight segments are parallel to each other and spaced apart, which can effectively prevent the two leads 400 from touching, rubbing or short-circuiting each other at the wire exit end, and improve the wiring neatness and electrical safety.

[0034] Optionally, in some embodiments, a normally open solenoid valve is further provided, such as Figures 8-10As shown, it includes: the aforementioned electromagnetic coil assembly; a valve body 500, having an inlet 510, an outlet 520, and a valve port 530 connecting the inlet 510 and the outlet 520, wherein the electromagnetic coil assembly is fixedly connected to the valve body 500; a stationary iron core 600, disposed within the central cavity of the cylindrical body 110, and fixedly connected to the valve body 500 to form a valve cavity, wherein the stationary iron core 600 has an axially penetrating through hole at its center; and a valve core assembly, including a movable rod 710, a transmission rod 720, a valve core 730, and a return spring 740, wherein the movable rod 710 is located within the cylindrical body. The transmission rod 720, located within the central cavity of the 110 and at the end of the stationary iron core 600 furthest from the valve body 500, passes through the through hole of the stationary iron core 600, with its two ends respectively engaging with the movable rod 710 and the valve core 730. The valve core 730 is located within the valve cavity and can slide axially. One end of the valve core 730 is fixedly connected to the transmission rod 720, and the other end is equipped with a sealing plug 731 for opening and closing the valve port 530. The return spring 740 acts on the valve core 730, forming a preload force on it towards the stationary iron core 600, so that the valve core 730 remains in an open state separated from the valve port 530 under normal conditions. The stationary iron core 600 can quickly attract the movable rod 710 under the action of a magnetic field. The return spring 740 is a helical compression spring, with one end abutting against the valve core 730 and the other end abutting against the inner wall of the valve cavity, providing a continuous preload force to the valve core 730. Under normal conditions, the preload of the return spring 740 pushes the valve core 730 to move, causing the sealing plug 731 to separate from the valve port 530, and the valve port 530 to be in the open state, allowing fluid to freely pass through the inlet 510, the valve chamber, and the outlet 520. When it is necessary to shut off the fluid, the external circuit is energized, and the electromagnetic coil assembly generates a magnetic field, attracting the movable rod 710. The movable rod 710, through the transmission rod 720, drives the valve core 730 to move against the preload of the return spring 740, causing the sealing plug 731 to fit tightly against the valve port 530, closing the valve port 530 and blocking the fluid flow.

[0035] Optionally, in some embodiments, a first sealing element 610 is provided between the stationary iron core 600 and the inner wall of the valve body 500, and a second sealing element 620 is provided between the stationary iron core 600 and the inner wall of the cylindrical body 110. Both the first sealing element 610 and the second sealing element 620 are annular elastic bodies. In this embodiment, both the first sealing element 610 and the second sealing element 620 are O-rings, installed in corresponding positions by interference fit to achieve sealing. The provision of the first sealing element 610 and the second sealing element 620 effectively seals the gap between the stationary iron core 600 and the valve body 500 and the cylindrical body 110, preventing fluid in the valve cavity from leaking from the gap and ensuring the sealing performance of the solenoid valve.

[0036] Optionally, in some embodiments, a coil bracket 550 is bolted to the upper end of the valve body 500, and the aforementioned electromagnetic coil assembly is fixed to the coil bracket 550. Further, as... Figure 11As shown, the valve body 500 has a stepped groove in its upper opening, and a spacer ring 540 is embedded in the stepped groove. The stationary iron core 600 has a raised limiting ring 630 at its lower end. The upper and lower ends of the limiting ring 630 respectively engage with the coil bracket 550 and the spacer ring 540 to limit the axial movement of the stationary iron core 600. Simultaneously, the upper surface of the spacer ring 540, the outer circumferential surface of the limiting ring 630, and the inner circumferential surface of the stepped groove of the valve body 500 together form a groove for the first sealing element 610, and the coil bracket 550 limits the upper end of the first sealing element 610 within the groove. The overall structure is compact and easy to install.

[0037] Alternatively, in some embodiments, the valve core 730 has the following structure: Figure 12 As shown, the valve core 730 has a T-shaped connecting block 734 at its bottom for connecting the sealing plug 731. The upper end of the valve core 730 mates with the transmission rod 720 and has a matching insertion hole 732 for the transmission rod 720 to be inserted into. Here, the matching means that the inner diameter of the insertion hole 732 matches the outer diameter of the transmission rod 720. During the opening and closing of the solenoid valve, the transmission rod 720 and the insertion hole 732 maintain a plug-in engagement relationship, and the transmission rod 720 provides radial restraint to the valve core 730, preventing radial drift of the valve core 730. No additional restraint structure is required. The plug-in engagement method makes the overall structure easy to assemble, especially for automated assembly.

[0038] Optionally, in some embodiments, the upper end face of the valve core 730 is provided with a radially penetrating groove 733. The groove 733 is used to prevent the valve core 730 from moving up to the limit position and sticking to the stationary iron core 600, which would cause the air gap to disappear due to the complete contact surface, thus preventing the valve core 730 from being properly separated and reset.

[0039] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An electromagnetic coil assembly, characterized in that, include: The coil frame (100) includes a cylindrical body (110) and end caps (120) located at both ends of the cylindrical body (110). The coil winding is wound around the outer periphery of the cylindrical body (110) and has lead-out ends; The connecting terminals (300) are electrically connected to the lead-out ends of the coil windings and are fixed to one side of the end cover (120); One end of the lead wire (400) is electrically connected to the connecting terminal (300), and the other end extends along the outer end face of the end cover (120) to the edge area beyond the end cover (120) away from the connecting terminal (300), forming an exposed section; The plastic-encapsulated housing (200) covers the coil bobbin (100), coil winding, connecting terminal (300) and lead wire (400), and exposes the exposed portion of the lead wire (400).

2. The electromagnetic coil assembly according to claim 1, characterized in that, The lead wire (400) and the connecting terminal (300) are connected by welding.

3. The electromagnetic coil assembly according to claim 1, characterized in that, The outer end face of the end cap (120) is provided with a wire-passing groove (121) for the lead wire (400) to pass through, and a gap is formed between the wire-passing groove (121) and the lead wire (400).

4. The electromagnetic coil assembly according to claim 3, characterized in that, The end cap (120) has a slot (122) on one side for inserting a fixed connection terminal (300). The slot (122) faces the outer end face of the end cap (120) and forms a height difference with the wire groove (121).

5. The electromagnetic coil assembly according to claim 4, characterized in that, The connection terminal (300) includes a insert body (310), a first connection part (320), and a second connection part (330). The insert body (310) is inserted into a slot (122) along the side of the end cap (120). The first connection part (320) is located outside the slot and is used to electrically connect with the lead end of the coil winding. The second connection part (330) is located outside the slot (122) and is used to electrically connect with the lead wire (400).

6. The electromagnetic coil assembly according to claim 5, characterized in that, The insert body (310) has several tooth-shaped protrusions (311) on both sides, and the protrusions (311) form an interference fit with the inner wall of the slot (122).

7. The electromagnetic coil assembly according to claim 6, characterized in that, The insert body (310) has at least two protrusions (311) arranged along the insertion direction on both sides. The slot (122) and the wire groove (121) are provided with a channel (123) in the area of ​​the corresponding insert body (310) to connect the two.

8. The electromagnetic coil assembly according to claim 3, characterized in that, The wire-passing groove (121) includes an arc segment surrounding the outer periphery of the cylindrical body (110) and a straight segment extending outward from the end of the arc segment away from the connecting terminal (300); Two leads (400) are provided, and a wire-passing groove (121) is provided for each of the two leads (400). The two wire-passing grooves (121) are set on an end cap (120). The arc segments of the two wire-passing grooves (121) are located on both sides of the cylindrical body (110) and are symmetrically distributed relative to the center line of the cylindrical body (110). The straight segments of the two wire-passing grooves (121) are arranged adjacent to each other at a certain distance and are parallel.

9. A normally open solenoid valve, characterized in that, include: The electromagnetic coil assembly as described in any one of claims 1-8; The valve body (500) is provided with an inlet (510), an outlet (520) and a valve port (530) connecting the inlet (510) and the outlet (520), and the electromagnetic coil assembly is fixedly connected to the valve body (500); A stationary iron core (600) is set in the central cavity of the cylindrical body (110) and is fixedly connected to the valve body (500) to form a valve cavity. The stationary iron core (600) has an axial through hole in the center. The valve core assembly includes a movable rod (710), a transmission rod (720), a valve core (730), and a return spring (740). The movable rod (710) is located in the central cavity of the cylindrical body (110) and at one end of the stationary iron core (600) away from the valve body (500). The transmission rod (720) passes through the through hole of the stationary iron core (600) and its two ends are respectively engaged with the movable rod (710) and the valve core (730). The valve core (730) is located in the valve cavity and can slide axially. One end of it is fixedly connected to the transmission rod (720), and the other end is provided with a sealing plug (731) for opening and closing the valve port (530). The return spring (740) acts on the valve core (730) to form a preload force on the stationary iron core (600), so that the valve core (730) is kept in an open state separated from the valve port (530) under normal conditions.

10. The normally open solenoid valve according to claim 9, characterized in that, A first sealing element (610) is provided between the static iron core (600) and the inner wall of the valve body (500), and a second sealing element (620) is provided between the static iron core (600) and the inner wall of the cylindrical body (110). Both the first sealing element (610) and the second sealing element (620) are annular elastic bodies.

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