Electromagnetic device with sunken welding electrode

Abstract

An external electrode of the electromagnetic device comprises a patch part, a main body part and a welding part which are arranged along a first direction, the first direction is the extension direction of the external electrode, the main body part and the welding part are arranged at a first side part of the electromagnetic device, and the welding part is welded with a lead of the electromagnetic device. The patch part is arranged on a second side part of the electromagnetic device and is used for being attached to the circuit board, and the second side part is vertically connected with the first side part; and along a second direction, the second direction is the thickness direction of the main body part and the welding part, the welding surface of the welding part and the exposed surface of the main body part are both back to the electromagnetic device, the welding surface of the welding part sinks into the first side surface of the electromagnetic device, and one end, connected with the patch part, of the main body part protrudes out of or is flush with the first side surface. According to the invention, the lead welding spots cannot shield the main body part in the vertical direction, so that the lead welding spots cannot shield SMT soldering tin when the patch part executes SMT mounting, and vertical AOI detection and judgment are facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of electromagnetic devices, and particularly relates to an electromagnetic device with a sunken welding electrode. Background Art

[0002] With the rapid development of technology, especially the emergence of multifunctional devices, the demand for the entire passive devices is increasing. As one of the passive components, electromagnetic devices are also widely used. Demands such as high current, high frequency, and high reliability are continuously upgraded. To meet this, the application of electromagnetic devices is becoming more and more extensive. An electromagnetic device at least includes a magnet, a winding, and an external electrode. The external electrode is bent into two parts. One part serves as a side electrode and fits on the side of the electromagnetic device. The side electrode is welded to the lead of the winding. The other part serves as a patch electrode and is SMT (Surface Mounted Technology) mounted with a circuit board (such as a PCB, i.e., Printed Circuit Board).

[0003] Obtaining high-quality solder joints based on SMT is the guarantee of the performance and reliability of electronic products. Currently, vertical AOI (Automated Optical Inspection) technology is generally used to check whether there are defects in the solder joints. The principle is that when observing vertically downward along the line of sight parallel to the side electrode, an optical technology is used to obtain an image of the detection position and analyze it. However, the solder joint after welding the side electrode and the lead (which can be called the "lead solder joint") is likely to protrude from the side electrode, so that along the line of sight parallel to the side electrode, even if the solder of the patch electrode and the circuit board (which can be called the "SMT solder") overflows the side electrode, it will be blocked by the lead solder joint, making it difficult to collect a qualified SMT solder image when using vertical AOI technology, which is not conducive to vertical AOI detection and determination. Summary of the Utility Model

[0004] In view of this, the present application provides an electromagnetic device with a sunken welding electrode, which can improve the problem that the lead solder joint of the external electrode blocks the SMT solder and is not conducive to vertical AOI detection and determination.

[0005] An electromagnetic device with a sunken welding electrode provided by the present application includes a magnet and an external electrode assembled with and exposed from the magnet. The external electrode includes a patch portion, a main body portion, and a welding portion arranged along a first direction, where the first direction is the extending direction of the external electrode. The main body portion and the welding portion are arranged on a first side portion of the electromagnetic device. The welding portion is welded to a lead of the electromagnetic device. The patch portion is arranged on a second side portion of the electromagnetic device and is used for mounting on a circuit board. The second side portion and the first side portion are two mutually perpendicular and connected side portions of the electromagnetic device. Along a second direction, where the second direction is the thickness direction of the main body portion and the welding portion, the welding surface of the welding portion and the exposed surface of the main body portion both face away from the electromagnetic device, and the welding surface of the welding portion is sunken below the first side surface of the electromagnetic device. The first side surface is located on the first side portion of the electromagnetic device, and one end of the main body portion connected to the patch portion protrudes from the first side surface of the electromagnetic device.

[0006] Optionally, along the second direction, the maximum height difference between the welding surface of the welding portion and the first side surface of the electromagnetic device is D1, and it satisfies: 0.5* ≤D1≤3.0* , where the is the wire diameter of the lead.

[0007] Optionally, a solder joint is provided at the welding position of the welding portion and the lead. Along the second direction, the solder joint is lower than the exposed surface of the main body portion.

[0008] Optionally, along the second direction, one end of the main body portion connected to the patch portion protrudes from the first side surface of the electromagnetic device. The maximum height difference between the exposed surface of the main body portion and the first side surface of the electromagnetic device is D2, and it satisfies: 0.5* ≤D2≤3.0* , where the is the wire diameter of the lead.

[0009] Optionally, the electromagnetic device further includes a winding arranged on a magnetic column of the magnet. Along the first direction, the winding is arranged opposite to the second side portion of the electromagnetic device, and one end of the main body portion connected to the patch portion is lower than the winding.

[0010] Optionally, the electromagnetic device further includes a winding arranged on a magnetic column of the magnet. Along the first direction, the winding is arranged opposite to the second side portion of the electromagnetic device, and one end of the main body portion connected to the patch portion extends to the winding and the magnetic column.

[0011] Optionally, the welding surface of the welding part and the exposed surface of the main body part are both parallel to the first direction. The welding part and the main body part are connected by a waist part, and along the third direction, the side of the waist part adjacent to the lead is recessed from the welding part and the main body part. The third direction is the width direction of the external connection electrode.

[0012] Optionally, the first side of the main body part is adjacent to the lead of the electromagnetic device; the welding part is used for welding with multiple leads of the electromagnetic device, and the first side of the main body part is parallel to the nearest lead; alternatively, the welding part is used for welding with one lead of the electromagnetic device, and the first side of the main body part is parallel to the lead.

[0013] Optionally, the maximum widths of the main body part and the welding part in the third direction are equal.

[0014] Optionally, the welding part is the end of the external connection electrode; or, the external connection electrode further includes an adhesive part connected to the welding part, the end of the lead extends to the adhesive part and is fixedly bonded by glue. Along the second direction, the adhesive part, the end of the lead and the glue are all recessed from the first side of the electromagnetic device.

[0015] As described above, the welding part of the present application is arranged on the first side part of the electromagnetic device, and the welding surface of the welding part is recessed from the first side surface of the first side part of the electromagnetic device. One end of the main body part connected to the patch part protrudes or is flush with the first side surface of the electromagnetic device, so that the lead solder joints will not block the main body part in the vertical direction, thereby ensuring that the SMT solder during SMT patching of the patch part will not be blocked, which is beneficial to vertical AOI detection and determination. Description of the Drawings

[0016] Figure 1 is a schematic structural diagram of a first perspective of an electromagnetic device according to an embodiment of the present application;

[0017] Figure 2 is a schematic structural diagram of a second perspective of an electromagnetic device according to an embodiment of the present application;

[0018] Figure 3 is Figure 1 and Figure 2 a schematic structural diagram of the first external connection electrode shown in;

[0019] Figure 4 is Figure 1 and Figure 2 a schematic structural diagram of the second external connection electrode shown in;

[0020] Figure 5 is a schematic structural diagram of a first perspective of an electromagnetic device according to another embodiment of the present application;

[0021] Figure 6 It is a schematic structural diagram of a second perspective of an electromagnetic device according to another embodiment of the present application;

[0022] Figure 7 is Figure 5 and Figure 6 a schematic structural diagram of the first external connection electrode shown;

[0023] Figure 8 is Figure 5 and Figure 6 a schematic structural diagram of the second external connection electrode shown.

[0024] First direction x, Second direction y, Third direction z, Preset direction L

[0025] External connection electrode 1, First external connection electrode 1a, Second external connection electrode 1b

[0026] Main body part 11, Welding part 12, SMT patch part 13, Waist part 14, Bonding part 15

[0027] Welding surface 120, Same side / exposed surface 110, Horizontal side 1210, Vertical side 1211

[0028] First side 111, Second side 141, Third side 121

[0029] Electromagnetic device 2

[0030] Winding 21, Magnet 22, Lead 210 Specific embodiments

[0031] To solve the above-mentioned technical problems existing in the prior art, in the electromagnetic device with a sunken welding electrode of the present application, the welding part is arranged on the first side of the electromagnetic device, and the welding surface of the welding part is sunken into the first side surface of the first side of the electromagnetic device. One end of the main body part connected to the SMT patch part protrudes or is flush with the first side surface of the electromagnetic device, so that the lead solder joint will not block the main body part in the vertical direction, thereby ensuring that the SMT solder during SMT patch mounting of the SMT patch part will not be blocked, which is beneficial to vertical AOI detection and determination.

[0032] The specific manifestation forms of parameters such as the shape, quantity, and size of any one of the SMT patch part, the main body part, and the welding part can be determined according to the requirements of the actual scenario.

[0033] To make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly described below in conjunction with specific embodiments and corresponding drawings. Obviously, the embodiments described below are only a part of the embodiments of the present application, rather than all the embodiments. Without conflict, the technical features of the following various embodiments can be combined with each other, and they also belong to the technical solution of the present application.

[0034] In the description of the embodiments of the present application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for facilitating the description of the technical solutions of the corresponding embodiments, rather than indicating or implying that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as a limitation to the present application.

[0035] Please refer to Figures 1 to 4 as shown. The electromagnetic device 2 includes an external electrode 1, a winding 21, and a magnet 22. The winding 21 can be formed by winding a lead 210 of a type such as enameled wire turn by turn, and the winding method depends on the adaptability; the winding 21 is disposed within the magnet 22. For example, a magnetic column can be provided within the magnet 22, and the winding 21 can be wound around the magnetic column to be assembled within the magnet 22 in this way. Each end of the lead 210 of the winding 21 can extend outside the magnet 22 and be welded to the corresponding external electrode 1. For example, in Figure 1 and Figure 2 the example shown, the electromagnetic device 2 is a pulse transformer. The winding 21 is provided with eight lead 210 ends, and the electromagnetic device 2 is provided with six external electrodes 1. The shapes of these six external electrodes 1 are different. For the convenience of description, two identical ones can be called the first external electrode 1a, and the other four identical ones can be called the second external electrode 1b. Four of the lead 210 ends are respectively welded to the four second external electrodes 1b in a one-to-one correspondence; two of the remaining four lead 210 ends are welded to one first external electrode 1a, and the other two are welded to the other first external electrode 1a.

[0036] Since there are two leads 210 welded to a single first external electrode 1a and one lead 210 welded to a single second external electrode 1b, that is, the number of leads 210 welded to a single first external electrode 1a is greater than the number of leads 210 welded to a single second external electrode 1b. Therefore, a single first external electrode 1a requires a larger welding area. In this regard, in the present application, when the lengths (or "extended lengths") of a single first external electrode 1a and a single second external electrode 1b are the same, the width of a single first external electrode 1a can be set to be greater than the width of a single second external electrode 1b.

[0037] Except for the different widths and other differences caused by the different widths, the structural shapes of a single first external electrode 1a and a single second external electrode 1b can be the same. Combining Figures 1 to 4 as shown, a single external electrode 1 is provided with a main body portion 11, a welding portion 12, and a patch portion 13.

[0038] For the convenience of description and understanding, in combination with Figures 1 to 4 the shown placement orientation, the height direction of the electromagnetic device 2 is referred to as the first direction x, the thickness direction is referred to as the second direction y, and the width direction is referred to as the third direction z. The first direction x, the second direction y, and the third direction z are perpendicular to each other in pairs and can be regarded as the three coordinate axes of a three-dimensional rectangular coordinate system. It should be understood that the so-called perpendicular throughout the present application does not require the angle between the two to be exactly 90°, but allows a deviation of, for example, ±10°, that is, the so-called perpendicular can be understood as the angle between any two directions being 80° to 100°. Similarly, the so-called parallel throughout the present application does not require the angle between the two to be exactly 0° or 180°, but allows a deviation of, for example, ±10°, that is, the so-called parallel can be understood as the angle between any two directions being 0° to 10° or 170° to 190°.

[0039] The patch portion 13, the main body portion 11, and the welding portion 12 are sequentially connected along the first direction x. For the external electrode 1, the first direction x is the length direction or the extension direction of the external electrode 1.

[0040] The welding portion 12 is provided with a welding surface 120, and the welding surface 120 is the surface for welding with the end of the lead 210 of the electromagnetic device 2. In one example, the welding surface 120 can be the entire outer surface of the welding portion 12, that is, the x-z surface. After the lead 210 of the electromagnetic device 2 extends out of the magnet 22, it extends along the preset direction L to the welding surface 120 of the welding portion 12 and is welded to the welding surface 120.

[0041] The main body portion 11 can be flush with the welding portion 12, so that when the external electrode 1 is assembled to the electromagnetic device 2, the welding surface 120 of the welding portion 12 is flush with the same side surface 110 of the main body portion 11. The main body portion 11 and the welding portion 12 are provided on the same side of the electromagnetic device 2, which is called the first side portion.

[0042] The patch portion 13 is provided on the second side portion of the electromagnetic device 2 and is used for mounting on a circuit board, such as SMT mounting. The second side portion is perpendicularly connected to the first side portion. In Figure 1 the shown placement orientation, the first side portion includes the left side and the right side of the electromagnetic device 2. For example, the main body portion 11 and the welding portion 12 of one first external electrode 1a and two second external electrodes 1b are provided on the left side of the electromagnetic device 2, and the main body portion 11 and the welding portion 12 of another first external electrode 1a and the other two second external electrodes 1b are provided on the right side of the electromagnetic device 2; the second side portion can be called the bottom side of the electromagnetic device 2.

[0043] The patch portion 13 is connected to one end of the main body portion 11 facing away from the waist portion 14, and the patch portion 13 extends parallel to the second direction y. When the external electrode 1 is assembled to the magnet 22, the patch portion 13 can serve as a patch electrode of the electromagnetic device 2, or a patch pin. The width of the patch portion 13 of a single first external electrode 1a (along the third direction z) is greater than the width of the patch portion 13 of a single second external electrode 1b.

[0044] Along the second direction y, which is the thickness direction of the main body portion 11 and the welding portion 12, the solder surface 120 of the welding portion 12 and the exposed surface 110 of the main body portion 11 (i.e., the aforementioned same side surface 110) both face away from the electromagnetic device 2, and the solder surface 120 of the welding portion 12 is sunken into the first side surface of the electromagnetic device 2. This first side surface is located at the first side portion of the electromagnetic device 2, that is, the outermost side surface of the electromagnetic device at the first side portion. One end of the main body portion 11 connected to the patch portion 13 protrudes from this first side surface of the electromagnetic device 2. Thus, in the vertical direction, that is, along the opposite direction of the first direction x, the solder joint (i.e., the lead solder joint) of the solder surface 120 and the lead 210 will not block the main body portion 11, at least not the end of the main body portion 11 connected to the patch portion 13, thereby ensuring that the SMT solder during the SMT mounting of the patch portion 13 will not be blocked, enabling the AOI device to capture the image of the SMT solder, which is beneficial for vertical AOI detection and determination.

[0045] It should be understood that in other examples, one end of the main body portion 11 connected to the patch portion 13 can be flush with this first side surface of the electromagnetic device 2 without protruding, but the solder surface 120 of the welding portion 12 is still sunken into the first side surface of the electromagnetic device 2. Thus, along the opposite direction of the first direction x, the solder joint of the solder surface 120 and the lead 210 will not block the end of the main body portion 11 connected to the patch portion 13 either, thereby ensuring that the AOI device can capture the image of the SMT solder, which is beneficial for vertical AOI detection and determination.

[0046] In one example, along the second direction y, the maximum height difference between the solder surface 120 of the welding portion 12 and the first side surface of the electromagnetic device 2 is D1, that is, the sinking depth of the welding portion 12 is D1, and it satisfies: 0.5* ≤D1≤3.0* where is the wire diameter of the lead 210. Thus, it can be ensured that the solder joint of the solder surface 120 and the lead 210 will not block the end of the main body portion 11 connected to the patch portion 13 in the vertical direction; that is to say, in this application, the solder joint can be set lower than the exposed surface 110 of the main body portion 11.

[0047] In one example, that is, for the example where the main body portion 11 protrudes from the first side portion of the electromagnetic device 2, along the second direction y, the maximum height difference between the exposed surface 110 of the main body portion 11 and the first side surface of the electromagnetic device 2 is D2, that is, the protruding height of the main body portion 11 is D2, and it satisfies: 0.5* ≤ D2 ≤ 3.0* , where the is the wire diameter of the lead 210. Here, it can be ensured that one end of the main body portion 11 connected to the patch portion 13 protrudes vertically from the solder joint surface 120 of the solder joint portion 12 and the lead 210.

[0048] Please continue to refer to Figures 1 to 4 As shown, the winding 21 of the electromagnetic device 2 is disposed opposite to the second side portion of the electromagnetic device 2, that is, there is a non-zero distance between the winding 21 and the magnetic column it winds and the bottom side of the electromagnetic device 2. It can be regarded that the winding 21 and the magnetic column it winds are suspended. In this regard, one end of the main body portion 11 connected to the patch portion 13 can be lower than the winding 21. That is to say, in this application, only a small part of the lower end of the main body portion 11 can protrude from the first side surface of the electromagnetic device 2.

[0049] In other examples, for example, please refer to Figures 5 to 8 the electromagnetic device 2 of another embodiment shown. One end of the main body portion 11 connected to the patch portion 13 extends to the winding 21 and the magnetic column in the first direction x. That is to say, in this application, only a relatively large part or the entire main body portion 11 of the main body portion 11 can protrude from the first side surface of the electromagnetic device 2.

[0050] Please continue to refer to Figures 1 to 4 As shown, the welding portion 12 and the main body portion 11 can be connected through a waist portion 14. And along the third direction z, that is, along the width direction of the external electrode 1, the side of the waist portion 14 adjacent to the lead 210 is recessed from the welding portion 12 and the main body portion 11.

[0051] Optionally, for any external electrode 1, the solder joint surface 120 of the welding portion 12 and the exposed surface 110 of the main body portion 11 are both parallel to the first direction x, and the maximum widths of the main body portion 11 and the welding portion 12 (that is, the maximum widths along the third direction z) can be equal. Please continue to refer to Figures 1 to 5 As shown, the side of the waist portion 14 adjacent to the lead 210 can be recessed from the main body portion 13 and the welding portion 12. The so-called recess can be understood as: on the side adjacent to the lead 210, the side edge of the waist portion 14 and the side edges of the main body portion 13 and the welding portion 12 are not a straight line parallel to the first direction x, and the side edge of the waist portion 14 is recessed in the direction away from the lead 210. For example, in Figures 1 to 4In the example, the first side 111 of the main body portion 11 is connected to the second side 141 of the waist portion 14, and both are adjacent to the lead 210 of the electromagnetic device 2; the welding portion 12 is provided with a third side 121 adjacent to the lead 210, the third side 121 is an arc-shaped side and is connected to the second side 141 of the waist portion 14, and the lead 210 extends to the welding portion 12 via the third side 121 of the welding portion 12. In the first external electrode 1a, the welding portion 12 is welded to multiple leads 210 of the electromagnetic device 2, and the first side 111 of the main body portion 11 can be parallel to the nearest lead 210; in the second external electrode 1b, the welding portion 12 is welded to one lead 210 of the electromagnetic device 2, and the first side 111 of the main body portion 11 can be parallel to this lead 210.

[0052] The concave design is equivalent to narrowing the heat transfer channel between the welding portion 12 and the main body portion 11, which can reduce the heat generated by welding of the welding portion 12 from being transmitted to the main body portion 11 and the electromagnetic device 2, that is, achieve heat insulation and improve or even eliminate the influence of this high temperature on the inductance performance.

[0053] In Figures 1 to 4 the example, the external electrode 1 further includes an adhesive portion 15 connected to the welding portion 12, the adhesive portion 15 is provided at one end of the welding portion 12 facing away from the main body portion 11, and the end of the lead 210 extends to the adhesive portion 15 and is adhesively fixed by glue.

[0054] The adhesive portion 15 can adhesively fix the end of the lead 210 with a high-temperature insulating glue, and the high-temperature insulating glue can wrap the end of the lead 210. Thus, when the lead 210 is welded to the welding portion 12, the end of the lead 210 is adhesively fixed, so that the lead retraction can be avoided during welding.

[0055] Along the second direction y, the adhesive portion 15, the end of the lead 210 and the glue are all sunken into the first side surface of the electromagnetic device 2, avoiding the cured glue and the lead 210 from blocking the end of the main body portion 11 connected to the patch portion 13, which is beneficial to vertical AOI detection and determination.

[0056] In one example, the adhesive portion 15 and the welding portion 12 can be flush.

[0057] The present application also provides an electromagnetic device 2 of another embodiment, please refer to Figures 5 to 8As shown, the same reference numerals are used in this application to identify structural elements with the same name. The welding portion 12 may be the end of the external electrode 1, that is, the bonding portion 15 is not provided; in addition, two patch portions 13 may be provided on a single first external electrode 1a in this example, and these two patch portions 13 are arranged opposite to each other in the third direction z; the third side 121 of the welding portion 12 in this example may include two perpendicularly connected sides, namely a horizontal side 1210 parallel to the third direction z and a vertical side 1211 parallel to the first direction x, and the lead 210 extends to the welding surface 120 through the horizontal side 121. The electromagnetic device 2 in this example and the foregoing Figure 1 and Figure 2 examples are the same, and reference can be made to each other, and details are not described herein again.

[0058] An embodiment of the present application further provides a transformer, including a magnet and the external electrode 1 described in any of the foregoing examples. Therefore, the transformer at least has the beneficial effects generated by the external electrode 1 in the corresponding example, and details are not described herein. For example, in combination with Figure 1 and Figure 2 shown, in an electromagnetic device 2 such as a transformer, a first external electrode 1a as shown in Figure 3 and a second external electrode 1b as shown in Figure 4 can be provided at the same time; in addition, when the external electrode 1 in any of the foregoing examples is assembled to the magnet 22, the main body portion 11, the waist portion 14, the welding portion 12 and the bonding portion 15 of a single external electrode 1 are located on the same side of the magnet 22, that is, the first side portion of the electromagnetic device 2, and the mounting portions 13 of all the external electrodes 1 are located on the same side of the magnet 22, that is, the second side portion of the electromagnetic device 2, and the second side 141 corresponding to the waist portion 14 of the lead 210 can be arranged opposite to each other.

[0059] The above are only some embodiments of the present application, and do not limit the patent scope of the present application. For those of ordinary skill in the art, any equivalent structural transformation made using the content of this specification and the drawings is equally included in the patent protection scope of the present application.

[0060] Although the terms "first", "second", etc. are used in this article to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. In addition, the singular forms "a", "an" and "the" are also intended to include the plural forms. The terms "or" and "and / or" are interpreted as inclusive, or mean any one or any combination. An exception to this definition only occurs when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way.

Claims

1. An electromagnetic device with a sunken welding electrode, comprising a magnet and an external electrode assembled with and exposed from the magnet, characterized in that, The external electrode includes a patch portion, a main body portion, and a welding portion arranged in a first direction, where the first direction is the extending direction of the external electrode. The main body portion and the welding portion are arranged on a first side portion of the electromagnetic device. The welding portion is welded to the lead of the electromagnetic device. The patch portion is arranged on a second side portion of the electromagnetic device and is used for mounting on a circuit board. The second side portion and the first side portion are two perpendicularly connected side portions of the electromagnetic device. Along a second direction, which is the thickness direction of the main body portion and the welding portion, the welding surface of the welding portion and the exposed surface of the main body portion both face away from the electromagnetic device, and the welding surface of the welding portion is sunken inside the first side surface of the electromagnetic device. The first side surface is located on the first side portion of the electromagnetic device. One end of the main body portion connected to the patch portion protrudes or is flush with the first side surface of the electromagnetic device.

2. The electromagnetic device with a sunken welding electrode according to claim 1, characterized in that Along the second direction, the maximum height difference between the welding surface of the welding part and the first side surface of the electromagnetic device is D1, and it satisfies: 0.5* ≤D1≤3.0* , where the is the wire diameter of the lead wire.

3. The electromagnetic device with a sunken welding electrode according to claim 2, characterized in that, A solder joint is provided at the welding position between the welding portion and the lead. Along the second direction, the solder joint is lower than the exposed surface of the main body portion.

4. The electromagnetic device with a sunken welding electrode according to any one of claims 1 to 3, characterized in that, Along the second direction, one end of the main body portion connected to the patch portion protrudes from the first side surface of the electromagnetic device, and the maximum height difference between the exposed surface of the main body portion and the first side surface of the electromagnetic device is D2, and it satisfies: 0.5* ≤D2≤3.0* , where the is the wire diameter of the lead wire.

5. The electromagnetic device with a sunken welding electrode according to claim 4, characterized in that, The electromagnetic device further includes a winding provided on a magnetic column of the magnet. Along the first direction, the winding is arranged opposite to the second side portion of the electromagnetic device. One end of the main body portion connected to the patch portion is lower than the winding.

6. The electromagnetic device with a sunken welding electrode according to claim 4, wherein, The electromagnetic device further includes a winding provided on a magnetic column of the magnet. Along the first direction, the winding is arranged opposite to the second side portion of the electromagnetic device. One end of the main body portion connected to the patch portion extends to the winding and the magnetic column.

7. The electromagnetic device with a sunken welding electrode according to claim 1, characterized in that, The welding surface of the welding portion and the exposed surface of the main body portion are both parallel to the first direction. The welding portion and the main body portion are connected by a waist portion. Along a third direction, which is the width direction of the external electrode, one side of the waist portion adjacent to the lead is sunken inside the welding portion and the main body portion.

8. The electromagnetic device with a sunken welding electrode according to claim 7, characterized in that, The first side edge of the main body portion is adjacent to the lead of the electromagnetic device. The welding portion is used for welding with multiple leads of the electromagnetic device, and the first side edge of the main body portion is parallel to the closest lead; or, the welding portion is used for welding with one lead of the electromagnetic device, and the first side edge of the main body portion is parallel to the lead.

9. The electromagnetic device with a sunken welding electrode according to claim 7, characterized in that, The maximum widths of the main body portion and the welding portion along the third direction are equal.

10. The electromagnetic device with a sunken welding electrode according to claim 1, wherein the welding portion is the end of the external electrode; or, the external electrode further includes an adhesive portion connected to the welding portion. The end of the lead extends to the adhesive portion and is fixed by glue bonding. Along the second direction, the adhesive portion, the end of the lead, and the glue are all sunken inside the first side surface of the electromagnetic device.

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