Sealed electromagnetic relay and method for assembling sealed electromagnetic relay

Abstract

The invention relates to a sealed type electromagnetic relay and an assembling method thereof, the sealed type electromagnetic relay comprises a fixed plate, a plurality of pins and a control unit, the fixed plate is provided with pads, the control unit is arranged at one side of the fixed plate and is connected with the pins, the pins pass through the corresponding pads, and the pins are connected with the control unit. Each pin is provided with a welding end welded to an external circuit board, and the welding ends are used for being connected with the external circuit board in a welded mode through second welding flux with the melting point lower than or not higher than that of the first welding flux. When the first welding flux is used for welding the pin and an external circuit board or the electromagnetic relay is applied to a high-temperature environment, the first welding flux is not easy to melt to generate a gap; and moreover, the pins can be well positioned and fixed, and the technical problem that the electrical life of the electromagnetic relay in a relatively high temperature environment is relatively poor due to the fact that mechanical parameters of the electromagnetic relay are easy to change is solved.

Description

Technical Field

[0001] The present application relates to the technical field of relays, and in particular to a sealed electromagnetic relay and an assembling method of a sealed electromagnetic relay. Background Art

[0002] At present, the pins connecting the moving reed and the stationary reed in the conventional electromagnetic relay are generally mounted on a plastic base, and the pins and the base are fixed to each other by filling the gap between the pins and the base with epoxy resin glue.

[0003] However, since the electromagnetic relay needs to be installed on the external circuit board through high-temperature welding, and the epoxy resin glue will melt after being heated, a certain proportion of the glue at the pins will have gaps or leaks after welding, resulting in failure of the relay plastic seal. As a result, it is difficult for traditional plastic-sealed electromagnetic relays to meet the sealing requirements in scenarios with high sealing requirements. Especially when the electromagnetic relay is used in a liquid application environment, the relay needs to be immersed in the liquid to work, so the sealing performance of the relay is required to be higher. In order to solve this problem, patent CN202111063315.7 "An electromagnetic relay and relay device that can be immersed in a liquid cooling environment" proposes a solution of extending the pins and flipping them into another shell before filling them with glue. The structure and process of this solution are complex, making the cost relatively high.

[0004] In addition, since the traditional electromagnetic relay base is made of plastic, when the electromagnetic relay is used in a high-temperature environment or the pins are welded to an external circuit board, the reed inserted into the base is prone to stress release. Coupled with the high temperature in the high-temperature environment, the above factors can easily cause the plastic base to deform, resulting in changes in the mechanical parameters of the electromagnetic relay, thereby making the electrical life of the electromagnetic relay in a higher temperature environment poor. Summary of the invention

[0005] Based on this, it is necessary to provide a sealed electromagnetic relay and an assembly method of a sealed electromagnetic relay that can solve the above technical problems, such as the complex structure and process of traditional electromagnetic relays to improve the sealing performance, and the easy deformation of traditional plastic bases, which leads to changes in the mechanical parameters of the electromagnetic relays, and thus poor electrical life performance of the electromagnetic relays in high temperature environments.

[0006] According to one aspect of the present application, there is provided a sealed electromagnetic relay, comprising a fixing plate, a control unit and a pin, wherein the control unit is arranged on one side of the fixing plate and connected to the pin;

[0007] The fixing plate is provided with a welding pad, and the welding pad is provided with a welding hole;

[0008] The pin passes through the corresponding solder hole and is connected to the corresponding solder pad by soldering with a first solder. The pin has a soldering end soldered to an external circuit board, and the soldering end is soldered to the external circuit board by a second solder having a melting point not higher than that of the first solder.

[0009] In one embodiment, the electromagnetic relay further includes a housing and a control unit, wherein the control unit is disposed in the housing and connected to the pin, one end of the housing has an opening, the fixing plate closes the opening of the housing, and the edges of the fixing plate are sealed to the inner wall of the housing.

[0010] In one embodiment, there are several control units, and the pins connected to each of the control units pass through a corresponding soldering hole on the fixed plate and are connected to a corresponding soldering pad through the first solder. The fixed plate is a circuit board, and a circuit is arranged on the circuit board so that all the control units are electrically connected to each other.

[0011] In one embodiment, the electromagnetic relay further comprises a shell, one end of which is open and houses all the control units, and the fixing plate closes the opening of the shell and is sealed to the shell.

[0012] In one of the embodiments, the fixing board is a PCB board, and the melting point of the first solder is greater than or equal to 290°C.

[0013] In one embodiment, the solder pad and the hole wall of the solder hole are covered with a conductive layer, and the first solder covers the conductive layer and fills the gap between the pin and the hole wall of the solder hole.

[0014] In one embodiment, the conductive layer is covered with a soldering layer, and the first solder covers the soldering layer.

[0015] According to another aspect of the present application, there is provided a method for assembling a sealed electromagnetic relay, comprising the following steps:

[0016] S1. Use positioning tooling to position the control unit and pins;

[0017] S2, inserting each of the pins into the corresponding pads on the fixed plate;

[0018] S3, using a first solder to weld the pins and the corresponding pads to each other, so as to fix the control unit on the fixing plate;

[0019] The melting point of the first solder is not lower than the melting point of the second solder used to solder the pin to the external circuit board.

[0020] In one embodiment, after step S3, the method further comprises the following steps:

[0021] S4, using a housing to cover the control unit in the housing, and using the fixing plate to close an opening at one end of the housing;

[0022] S5, using sealant to seal the fixing plate and the housing;

[0023] Wherein, in step S4, if there are multiple control units, the housing covers all the control units inside itself.

[0024] In one embodiment, the positioning tool includes a tool shell and a plurality of spring clips disposed in the tool shell, and the tool shell is used to dispose the control unit and the pin cover inside itself, wherein some of the spring clips are used to abut the pins, and other parts of the spring clips are used to abut the control unit, so that the positioning tool can be used to position the pins and the control unit in step S1.

[0025] Compared with the prior art, this application has the following beneficial effects:

[0026] 1. The sealed electromagnetic relay provided in the present application adopts a fixed plate with multiple solder pads, multiple pins are inserted into the fixed plate with multiple solder pads, and the pins are soldered to the solder pads of the fixed plate by using a first solder with a higher melting point. When the pins are soldered to an external circuit board by using a second solder with a lower melting point than the first solder or when the electromagnetic relay is used in a high temperature environment, the first solder at the welding point between the pins and the fixed plate is not easy to melt and produce gaps, thereby achieving higher sealing performance.

[0027] 2. The sealed electromagnetic relay provided in the present application, by preferably making the fixed plate a PCB board, cleverly utilizes the high temperature resistance of the PCB board itself, so that when the electromagnetic relay is used in a high temperature environment or the pins are soldered to an external circuit board, the PCB board is not easy to deform, and the mechanical parameters of the components inserted on the PCB board are less affected by the high temperature environment, thereby solving the technical problem that the mechanical parameters of the electromagnetic relay are prone to change, resulting in poor electrical life performance of the electromagnetic relay in a relatively high temperature environment, and making the electromagnetic relay have better high temperature electrical life performance; at the same time, it also cleverly utilizes the characteristics of the PCB board itself with a soldering pad, and utilizes the performance of the soldering pad and the conventional low cost advantage of the PCB board to realize a sealing solution. The entire solution does not require special processes or special customization, the solution is simple, and the sealing effect is significant.

[0028] 3. The sealed electromagnetic relay provided in the present application covers the soldering pads on both sides of the fixed plate and the hole walls of the soldering holes with a conductive layer, so that the soldering pads on both sides and the inner walls of the soldering holes are connected as a whole through the conductive layer. During welding, the first solder that is melted by heat is affected by gravity (wave crest impact force in the case of wave soldering) and tension to cover the gap between the soldering pad and the pin and the soldering hole, thereby welding the pin, the soldering pad and the conductive layer of the inner wall of the soldering hole together.

[0029] 4. To improve the welding quality, it is preferred to cover the side of the conductive layer away from the pad with a soldering layer, so as to effectively utilize the characteristics of the pad metal plating, gravity and surface tension. When the first solder melts, it can automatically spread over the gap between the pad, pin and solder hole to form a sealed whole with a large contact area, rather than just sticking to the pin and hole, so as to achieve a better sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the appearance of a sealed electromagnetic relay provided in one embodiment of the present application.

[0031] Figure 2 A schematic diagram of the internal structure of a sealed electromagnetic relay provided in one embodiment of the present application.

[0032] Figure 3 A cross-sectional view of the internal structure of a sealed electromagnetic relay provided in one embodiment of the present application.

[0033] Figure 4 A cross-sectional view of a pin and a pad on a PCB board being welded to each other according to an embodiment of the present application.

[0034] Figure 5 An exploded schematic diagram of the magnetic circuit portion of a sealed electromagnetic relay provided in one embodiment of the present application.

[0035] Figure 6 A schematic diagram of the internal structure of a sealed electromagnetic relay provided in another embodiment of the present application.

[0036] Figure 7 This is a schematic diagram of the appearance of a sealed electromagnetic relay provided in another embodiment of the present application.

[0037] Figure 8 A schematic diagram of the steps of an assembly method of a sealed electromagnetic relay provided in one embodiment of the present application.

[0038] Fig. 9 A schematic diagram of the structure of a positioning tool in an assembly method of a sealed electromagnetic relay provided in an embodiment of the present application Figure 1 .

[0039] Fig.10A schematic diagram of the structure of a positioning tool in an assembly method of a sealed electromagnetic relay provided in an embodiment of the present application Figure 2 .

[0040] Fig.11 A cross-sectional view of a positioning tool in an assembly method of a sealed electromagnetic relay provided in an embodiment of the present application.

[0041] Fig.12 A schematic diagram of the appearance of an insulating shell in a sealed electromagnetic relay provided in one embodiment of the present application.

[0042] Fig.13 This is a schematic diagram of a sealed electromagnetic relay provided in an embodiment of the present application, wherein a control unit and pins are fixed in a positioning fixture during assembly.

[0043] Fig.14 This is a schematic diagram of a sealed electromagnetic relay provided by another embodiment of the present application, in which a control unit and pins are fixed in a positioning tool during assembly.

[0044] Description of reference numerals:

[0045] 10. Electromagnetic relay; 100. Housing; 200. Control unit; 210. Contact part; 211. Normally open static spring; 212. Normally closed static spring; 213. Moving spring; 220. Magnetic circuit part; 221. Coil; 222. Armature push block; 223. Insulating shell; 223a. Shell shoulder; 300. Pin; 310. First pin; 320. Second pin; 330. Third pin; 340. Fourth pin; 400. Fixing plate; 401. Welding side; 402. Mounting side; 403. Solder pad; 404. Solder hole; 50. Positioning tool; 51. Tool shell; 52. Spring clip; 521. First spring clip; 522. Second spring clip; 523. Third spring clip; 524. Fourth spring clip; 525. Fifth spring clip; 60. First solder; 70. Conductive layer; 80. Soldering layer. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0047] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0048] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0049] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0050] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0051] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0052] The present application provides a sealed electromagnetic relay, which is used in an automatic control circuit and plays the role of automatic adjustment, safety protection, circuit conversion, etc. in the circuit. For example, it can be used to connect a load power supply and a load, and control the on-off of the circuit between the load power supply and the load, thereby protecting the load through circuit conversion and automatic adjustment, and avoiding the situation where the load is damaged by excessive current.

[0053] The structure of the sealed electromagnetic relay and the steps of the assembly method of the sealed electromagnetic relay in the present application are described below. It is understandable that the sealed electromagnetic relay of the present application can be any electronic relay used in the fields of industrial control, automation, mechanical equipment, new energy, chemical industry, etc., and is not limited here.

[0054] See also Figures 1 to 3 , Figure 1 1 shows a schematic diagram of the appearance of a sealed electromagnetic relay (hereinafter referred to as electromagnetic relay 10) in an embodiment of the present application. Figure 2 FIG. 1 shows a schematic diagram of the internal structure of the electromagnetic relay 10 in this embodiment. Figure 3 The electromagnetic relay 10 is shown in a cross-sectional view of the internal structure. The electromagnetic relay 10 provided by an embodiment of the present application includes a housing 100, a control unit 200, a pin 300 and a fixing plate 400, wherein the control unit 200 is arranged in the housing 100, one end of the housing 100 has an opening, the fixing plate 400 closes the opening of the housing 100 and is sealed with the housing 100, and its two opposite sides are respectively defined as an installation side 402 and a welding side 401; the control unit 200 is located on the installation side 402, and there are a plurality of pins 300, all of which are connected to the control unit 200 and penetrated through the fixing plate 400, so that one end of the pin 300 is exposed on the fixing plate 400 and is located on the welding side 401, and one end of the pin 300 located on the welding side 401 is defined as a welding end, and the welding end is used to be welded and connected with an external circuit board, so that the control unit 200 can be electrically connected to the external circuit board, so that the control unit 200 can control the circuit on and off of the external circuit board or control the circuit on and off of the electromagnetic relay 10 itself.

[0055] Specifically, in one embodiment, if Figure 2 and Figure 3 As shown, the plurality of pins 300 include a first pin 310, a second pin 320, a third pin 330 and a fourth pin 340, the control unit 200 includes a contact portion 210 and a magnetic circuit portion 220, the contact portion 210 includes a normally open static spring 211, a normally closed static spring 212 and a dynamic spring 213, the normally open static spring 211 is connected to the first pin 310, the dynamic spring 213 is connected to the second pin 320, the normally closed static spring 212 is connected to the third pin 330, and the combination Figure 5 As shown, the magnetic circuit part 220 includes a coil 221 connected to the fourth pin 340 and an armature push block 222 connected to the movable spring 213. When all the pins 300 are welded and connected to the external circuit board, the first pin 310 is connected to the load power supply of the external circuit board, the second pin 320 is connected to the load of the external circuit board, and the external circuit board can control the coil 221 to be energized or deenergized through the fourth pin 340.

[0056] In this way, when the coil 221 is energized, the coil 221 can generate electromagnetic force, and the armature push block 222 can push the movable spring 213 to move and cause the movable spring 213 to produce elastic deformation under the action of the electromagnetic force, so that the movable spring 213 contacts the normally open static spring 211. At this time, the movable spring 213, the external circuit board and the normally open static spring 211 form a normally open circuit, so that the load power supply and the load are mutually conductive; when the coil 221 is de-energized, the electromagnetic force disappears, and the movable spring 213 can drive the armature push block 222 to reset together under the action of the elastic force generated by its own elastic deformation, so as to disengage from the normally open static spring 211. At this time, the movable spring 213 contacts the normally closed static spring 212 to form a normally closed circuit, so that the load power supply and the load are disconnected. In this way, through the above actions, the control unit 200 achieves the purpose of controlling the circuit on and off of the external circuit board.

[0057] It is understandable that in other embodiments, the normally closed static spring 212 may not be provided, and / or the coil 221 may not be connected to the external circuit board through the pin 300, that is, the coil 221 is not powered on or off by the external circuit board. In this case, all the pins 300 may not include the third pin 330 and the fourth pin 340, as long as the first pin 310 and the second pin 320 are included. However, it is obvious that by providing the normally closed static spring 212, the movement of the moving spring 213 can be blocked when the moving spring 213 is reset, so as to reduce the vibration of the moving spring 213 and accelerate the moving spring 213 to be in a static state; and by connecting the coil 221 to the external circuit board through the fourth pin 340, the coil 221 can be powered without the help of an external power supply, so that the structure of the electromagnetic relay 10 can be simplified, which is obviously the best embodiment.

[0058] It can also be understood that in other embodiments, the electromagnetic relay 10 may not include the housing 100. In this case, the electromagnetic relay 10 can also achieve its function of turning on or off the load circuit, but by providing the housing 100, the control unit 200 can be protected and sealed, so that the electromagnetic relay 10 can be used in harsh environments such as liquid cooling environments or high temperature environments.

[0059] However, it is worth noting that the pin 300 connecting the moving spring and the static spring in the traditional electromagnetic relay is generally installed on a plastic base, and the pin 300 and the base are fixed to each other. Since the base of the traditional electromagnetic relay is made of plastic, when the electromagnetic relay is used in a high temperature environment or the pin 300 is welded to an external circuit board, the spring inserted into the base is prone to stress release, and the high temperature in the high temperature environment is prone to deformation of the plastic base, resulting in changes in the mechanical parameters of the electromagnetic relay (such as reduction or increase in overtravel), which in turn makes the electrical life of the electromagnetic relay in a higher temperature environment poor.

[0060] It is also worth noting that after the conventional electromagnetic relay is sealed and connected to the base, the pin 300 and the base are fixed to each other by filling the gap between the pin 300 and the base with epoxy resin glue. When the pin 300 is welded to the external circuit board, the epoxy resin glue will melt due to heat, thereby causing the plastic sealing of the electromagnetic relay to fail. Therefore, when the sealing requirements of the electromagnetic relay are strict, such as when it is used in harsh environments such as liquid cooling or high temperature environments, the electromagnetic relay will be damaged. If the sealing performance of the electromagnetic relay is to be guaranteed, such as when it is immersed in liquid, it must be sealed with multiple layers of glue or the pins must be extended and flipped into another shell before glue filling. This not only leads to complex structure and process, but also high production costs.

[0061] In addition, in some other embodiments, the electromagnetic relay is a coupling relay composed of a plurality of control units 200 electrically connected and assembled, and the plastic sealing also requires a plurality of housings 100 for plastic sealing, which not only occupies space but also has poor sealing performance.

[0062] Therefore, in view of the above problems, the applicant of the present application has thought of improving the traditional electromagnetic relay 10. Figure 2 and Figure 3 In the improved embodiment, the fixing plate 400 may be a PCB board (i.e., a circuit board or a fixing plate 400 made of the same material as the circuit board), and the fixing plate 400 has a plurality of pads 403 (e.g., Figure 4As shown in the figure, each pad 403 is provided with a solder hole 404, so that each pin 300 can pass through a corresponding solder hole 404 and be soldered to the corresponding pad 403 through the first solder 60. The melting point of the first solder 60 is not lower than the melting point of the second solder used for soldering the soldering end of the pin 300 to the external circuit board. Exemplarily, the first solder 60 is a high melting point material greater than the melting point of ordinary solder, such as high melting point tin, whose melting point is greater than or equal to 290°C, such as 290°C-350°C, but not limited thereto; and the second solder is a low melting point material, such as ordinary melting point tin, whose melting point is 240°C-260°C, or it can be a silver paste of about 125°C, but not limited thereto.

[0063] In this way, under the premise that the fixed plate 400 is sealed and connected to the housing 100, and when the pin 300 is soldered to the external circuit board through the second solder, the first solder 60 will not melt at the melting point of the second solder, or when the electromagnetic relay 10 is used in a high temperature environment, the first solder 60 at the welding point of the pin 300 and the fixed plate 400 is not easy to melt and produce gaps. Therefore, the improved electromagnetic relay 10 has higher sealing performance, and the technical effect of the electromagnetic relay 10 not leaking and failing in a liquid cooling environment is achieved without the need for multi-layer glue potting and plastic sealing.

[0064] Because there is no need to perform plastic sealing through multiple layers of glue pouring, a relatively simple structure can be used for sealing the fixed plate 400 and the outer shell 100. For example, the edges of the fixed plate 400 and the inner wall of the outer shell 100 are sealed with a small amount of sealant, or a layer of sealant can be poured into the sealing position formed by the side surface of the fixed plate 400 facing the welding side 401 and the inner wall of the outer shell 100 to fill the sealing position.

[0065] It can be seen that, through the improvement of the above embodiment, the electromagnetic relay 10 can have better sealing performance in a smaller installation space and with fewer parts, and because the fixing plate 400 can be a PCB board, the commonly used materials of the PCB board include epoxy resin (FR-4), high-temperature FR-4, metal substrate, polyimide (PI), fluoroplastic (PTFE), ceramic, etc., so the high-temperature resistance of the PCB board itself is cleverly utilized, so that when the electromagnetic relay 10 is used in a high-temperature environment or the pin 300 is welded with an external circuit board, the PCB board is not easy to deform, and the mechanical parameters of the components inserted on the PCB board are less affected by the high-temperature environment, which solves the problem. The mechanical parameters of the electromagnetic relay 10 are prone to change, resulting in a technical problem that the electromagnetic relay 10 has a poor electrical life performance in a relatively high temperature environment, so that the electromagnetic relay 10 has a better high-temperature electrical life performance; and because the PCB board itself has a soldering pad 403, the pin 300 can use the soldering pad 403 on the PCB board to be soldered to the PCB board, thus utilizing the performance of the soldering pad 403 and the conventional low cost of the PCB board to achieve a sealing solution. The entire solution does not require special processes or special customization, and the solution is simple. While improving the sealing effect, it can reduce the steps of assembling the electromagnetic relay 10, saving material costs and labor costs. Of course, the fixed plate 400 is not limited to a PCB board, and can also be other fixed plates 400 with soldering pads 403, which are not limited here.

[0066] Further, see Figure 4 , Figure 4 A cross-sectional schematic diagram of a fixing plate 400 in a preferred embodiment is shown. Figure 4 In the illustrated embodiment, the pad 403 and the hole wall of the solder hole 404 are covered with a conductive layer 70, and the first solder 60 covers the conductive layer 70 and fills the gap between the pin and the hole wall of the solder hole 404. Exemplarily, the conductive layer 70 can be a layer of copper foil, and of course it can also be a coating formed by other conductive materials. In this way, the pads 403 on both sides of the fixed plate 400 can be connected to each other through the conductive layer 70, so that during welding, the first solder 60 after being melted by heat covers the gap between the pad 403 and the pin and the solder hole 404 under the action of gravity (wave crest impact force if wave soldering) and tension, and welds the pin 300, the pad 403 and the conductive layer 70 on the inner wall of the solder hole 404 together.

[0067] Preferably, in order to improve the welding quality, the conductive layer 70 may be covered with a soldering layer 80, and the first solder 60 may cover the soldering layer 80; the soldering layer 80 may be a layer of gold plated on the conductive layer 70 or a layer of tin sprayed on the conductive layer 70, or may be a soldering flux, so that the characteristics of the metal plating, gravity and surface tension on the pad 403 are effectively utilized, so that when the solder melts, it can automatically fill the gap between the pad 403, the pin and the solder hole 404, thereby forming a sealed whole with a large contact area, rather than just sticking to the pin 300 and the solder hole 404, so that the first solder 60 can be tightly connected to the fixed plate 400, the pad 403 and the pin 300, and the sealing effect is better.

[0068] More preferably, the contact area between the first solder 60 and the fixing plate 400 may be increased by increasing the size of the solder pad 403 to further improve the sealing performance.

[0069] See also Figure 6 , is another improved electromagnetic relay 10 of another embodiment. The electromagnetic relay 10 of this embodiment is the coupling relay mentioned above, which is composed of a plurality of control units 200 electrically connected to each other. The structure of the control unit 200 is the same as the structure of the control unit 200 in the electromagnetic relay 10 with only a single control unit 200, and will not be repeated here. Specifically, in this embodiment, the fixed plate 400 can be a PCB board that is not provided with a circuit and simply serves as a fixed seal, or it can be a PCB board directly provided with a circuit. Each pin 300 connected to each control unit 200 passes through a corresponding welding hole 404 on the fixed plate 400, and is also welded to a corresponding welding pad 403 on the fixed plate 400 through a first solder 60, so that all control units 200 can be electrically connected to each other through the circuit board. Of course, all pins 300 can also be connected to an external circuit board to achieve mutual electrical connection. In this way, the control unit 200 can realize the control of the circuit on and off of the external circuit board or the electromagnetic relay 10 itself.

[0070] Further, see Figure 7 The electromagnetic relay 10 of this embodiment also includes a housing 100, one end of which is open and all the control units 200 are covered inside the housing. Similarly, the fixing plate 400 closes the opening of the housing 100 and is sealed with the housing 100. The sealing structure is the same as the sealing structure described in the previous embodiment, and will not be described in detail here. Of course, the housing 100 may not be provided, or the control unit 200, the fixing plate 400 and the external circuit board may share a housing 100, which is not limited here.

[0071] It can be seen that the improved coupling relay, by connecting several control units 200 to a fixed plate 400 and sharing a housing 100, can not only achieve the technical effects of good sealing and high temperature resistance and non-deformation of the fixed plate 400 of the electromagnetic relay 10 composed of the above-mentioned single control unit 200, but also reduce the number of housings 100 and fixed plates 400, thereby simplifying the structure, reducing the installation volume and the overall number of parts, and thus reducing costs.

[0072] The embodiment of the present application also provides an assembly method of the electromagnetic relay 10. The assembly method is a method for assembling the improved electromagnetic relay 10. Figures 8 to 14 The specific implementation steps of the assembly method are introduced.

[0073] S1, positioning the control unit 200 and the plurality of pins 300 using the positioning tool 50. Specifically, Figures 9 to 12 As shown, the positioning tool 50 includes a tool shell 51 and a plurality of spring pieces 52 arranged in the tool shell 51. The tool shell 51 is used to cover the control unit 200 and the pin 300 in the tool shell 51, wherein some of the spring pieces 52 are used to abut the pin 300, and other parts of the spring pieces 52 are used to abut the control unit 200, so that in this step, the positioning tool 50 can be used to abut the pin 300 and the control unit 200. Fig.10 and Fig.11 Positioning is performed in the X and Y directions shown in FIG.

[0074] In a specific embodiment, see Figure 2 , Figure 3 and Fig.12 The control unit 200 in the electromagnetic relay 10 further includes an insulating shell 223, and the coil 221 is disposed in the insulating shell 223; Figures 9 to 11 The plurality of spring pieces 52 disposed in the tooling shell 51 include a first spring piece 521, a second spring piece 52252, a third spring piece 523, a fourth spring piece 524 and a fifth spring piece 525, wherein the first spring piece 521, the second spring piece 522, the third spring piece 523 and the fourth spring piece 524 have two spring pieces, respectively. Fig.13 As shown, the two first spring pieces 521 are respectively abutted against a corresponding first pin 310, the two second spring pieces 522 are respectively abutted against a corresponding second pin 320, and the two third spring pieces 523 are respectively abutted against a corresponding third pin 330. Fig.12 As shown, the two fourth elastic pieces 524 abut against the two shell shoulders 223 a of the insulating shell 223 , and the fifth elastic piece 52552 abuts against the core section of the magnetic circuit portion 220 .

[0075] Preferably, if Fig.10 , Fig.11 and Fig.13As shown, the tooling shell 51 has a step surface, a positioning groove and a baffle, etc., which are used to abut against the features of the control unit 200 to play an auxiliary positioning role, so that combined with the positioning of the spring 52, the control unit 200 and the pin 300 can be positioned in all directions. Preferably, the tooling shell 51 is made of a high-temperature resistant metal material or a polymer material, so that it can not be deformed in a high-temperature environment.

[0076] S2, each pin 300 is inserted into the corresponding pad 403 on the fixing plate 400. As described above, the fixing plate 400 has a plurality of pads 403, and the pads 403 are provided with welding holes 404. Each pin 300 is inserted into the pad 403 on the fixing plate 400, so that the control unit 200 is located on the installation side 402 of the fixing plate 400, and the welding end of the pin 300 is located on the welding side 401 of the fixing plate 400.

[0077] S3, using the first solder 60 to weld the pin 300 and the corresponding pad 403 to each other, so as to fix the control unit 200 on the fixed plate 400. In some embodiments, the control unit 200 includes a magnetic circuit part 220 and a contact part 210, and the contact part 210 includes an armature push block 222. In the initial state, the armature push block 222 and the magnetic circuit part 220 can be separated from each other, or can be connected to each other in the initial state. Therefore, after the pads 403 corresponding to the pin 300 are welded to each other by the first solder 60, the magnetic circuit part 220 can be first fixed to the fixed plate 400, and then the armature push block 222 is installed to the magnetic circuit part 220 to complete the fixed connection between the control unit 200 as a whole and the fixed plate 400; or the pin 300 can be passed through the fixed plate 400 and the pin 300 and the corresponding pad 403 are welded and fixed to each other by the first solder 60, and then the armature push block 222 is inserted to fix the control unit 200 as a whole to the fixed plate 400. In this step, welding can be performed manually or by reflow soldering using a machine, without specific limitation.

[0078] It can be seen that by using the positioning fixture 50 to fix the control unit 200 and the pin 300 before connecting the fixing plate 400 and the pin 300 to each other, the simple structure of the fixing plate 400 can be used to achieve precise positioning with the pin 300, thereby simplifying the assembly steps and greatly simplifying the structure of the electromagnetic relay 10. There is no need to carry out complex design of the fixing plate 400, saving the manufacturing cost of the relay.

[0079] Furthermore, if the electromagnetic relay 10 includes a housing 100, after the above step S3, the following steps are further included:

[0080] S4, using the housing 100 to cover the control unit 200 in the housing 100, and using the fixing plate 400 to close an opening at one end of the housing 100;

[0081] S5. Use sealant to seal the fixing plate 400 and the housing 100, thereby finally completing the assembly of the electromagnetic relay 10. As mentioned above, in this step, the sealing method can be to seal the edges of the fixing plate 400 and the inner wall of the housing 100 with a small amount of sealant, or to pour a layer of sealant into the sealing position formed by the surface of one side of the fixing plate 400 facing the welding side 401 and the inner wall of the housing 100 to fill the sealing position.

[0082] It should be noted that if the electromagnetic relay 10 is a coupling relay and the control unit 200 has a plurality of coupling relays, in step S1, Figure 5 and Fig.14 As shown, firstly, a plurality of positioning fixtures 50 are used to position the corresponding control units 200 respectively; in step S3, the pins 300 connected to all control units 200 are welded and connected to a fixing plate 400; and then, Figure 6 As shown, in step S4, the housing 100 covers all the control units 200 inside itself, so as to simplify the structure and reduce the installation volume and the number of overall parts.

[0083] It can be seen that the electromagnetic relay 10 assembled by the above-mentioned assembly method not only has good sealing performance, but also because the high-temperature resistant PCB board is not easy to deform, the reed and the control unit 200 fixedly connected to the PCB board (i.e., the fixed plate 400) are firmly fixed, so that the mechanical properties of the electromagnetic relay 10 are stable, and the mechanical parameters are less affected by the high-temperature environment. Therefore, the high-temperature electrical life of the electromagnetic relay 10 can be greatly improved, which perfectly solves a series of problems existing in the traditional electromagnetic relay 10.

[0084] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A sealed electromagnetic relay, comprising a fixing plate, a control unit and a pin, wherein the control unit is arranged on one side of the fixing plate and connected to the pin, characterized in that : The fixing plate is provided with a welding pad, and the welding pad is provided with a welding hole; The pin passes through the corresponding solder hole and is connected to the corresponding solder pad by soldering with a first solder. The pin has a soldering end soldered to an external circuit board, and the soldering end is soldered to the external circuit board by a second solder having a melting point not higher than that of the first solder.

2. The sealed electromagnetic relay according to claim 1, characterized in that: The electromagnetic relay also includes a shell, the control unit is arranged in the shell and connected to the pin, one end of the shell has an opening, the fixing plate closes the opening of the shell, and the edges of the fixing plate are sealed with the inner wall of the shell.

3. The sealed electromagnetic relay according to claim 1, characterized in that: The control units include a plurality of control units, and the pins connected to each of the control units pass through a corresponding soldering hole on the fixing plate and are connected to a corresponding soldering pad by soldering with the first solder. The fixing plate is a circuit board, and a circuit is arranged on the circuit board so that all the control units are electrically connected to each other.

4. The sealed electromagnetic relay according to claim 3, characterized in that: The electromagnetic relay further comprises a shell, one end of which is open and covers all the control units inside the shell, and the fixing plate closes the opening of the shell and is sealed with the shell.

5. The sealed electromagnetic relay according to claim 1, characterized in that: The fixing plate is a PCB board, and the melting point of the first solder is greater than or equal to 290°C.

6. The sealed electromagnetic relay according to claim 1, characterized in that: The pad and the hole wall of the welding hole are covered with a conductive layer, and the first solder covers the conductive layer and fills the gap between the pin and the hole wall of the welding hole.

7. The sealed electromagnetic relay according to claim 6, characterized in that: The conductive layer is covered with a soldering layer, and the first solder covers the soldering layer.

8. A method for assembling a sealed electromagnetic relay, characterized in that: The following steps are involved: S1. Use positioning tooling to position the control unit and pins; S2, inserting each of the pins into the corresponding pads on the fixed plate; S3, using a first solder to weld the pins and the corresponding pads to each other, so as to fix the control unit on the fixing plate; The melting point of the first solder is not lower than the melting point of the second solder used to solder the pin to the external circuit board.

9. The assembly method according to claim 8, characterized in that: After step S3, the method further includes the following steps: S4, using a housing to cover the control unit in the housing, and using the fixing plate to close an opening at one end of the housing; S5, using sealant to seal the fixing plate and the housing; Wherein, in step S4, if there are multiple control units, the housing covers all the control units inside itself.

10. The assembly method according to claim 8, characterized in that: The positioning tool includes a tool shell and a plurality of spring clips arranged in the tool shell. The tool shell is used to arrange the control unit and the pin cover inside itself, wherein some of the spring clips are used to abut the pins, and other parts of the spring clips are used to abut the control unit, so that the positioning tool can be used to position the pins and the control unit in step S1.

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