Assembling method and structure of microcircuit module board-level magnetic core

Abstract

The invention provides an assembling method and structure of a microcircuit module board-level magnetic core, and the assembling method comprises the following steps: firstly forming a board-level magnetic core assembling groove in a PCB, then smearing a layer of silicone rubber on the side wall of the assembling groove, then smearing modified magnetic core bonding glue at the bonding position of the board-level magnetic core, then heating the bonding position of the board-level magnetic core, and finally, carrying out the assembling of the board-level magnetic core. The magnetic core bonding glue is solidified, then a gap between the board-level magnetic core and the assembling groove is blocked, and finally the PCB is installed in the microcircuit module shell. According to the invention, the board-level magnetic core assembling groove which accords with the installation of the board-level magnetic core is formed in the PCB, the phenomenon that the magnetic core bonding interface is expanded is avoided, the inner side wall of the assembling groove is coated with the silicone rubber layer, the magnetic core bonding interface is prevented from being cracked by pulling, and the board-level upper magnetic core and the board-level lower magnetic core are connected by adopting the modified magnetic core bonding glue, so that the magnetic core bonding interface is prevented from being cracked by pulling. In batch assembly, a hard ceramic chip does not need to be added to control an air gap and a sensing value, so that the assembly difficulty is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This application relates to the technical field of board-level magnetic core assembly of microcircuit modules, and particularly to an assembly method and structure of a board-level magnetic core of a microcircuit module. Background Art

[0002] The board-level magnetic core is the main component of the transformer and inductor of the microcircuit module, and the reliability of the board-level magnetic core assembly directly affects the electrical performance of the microcircuit module. During the entire life cycle of the board-level magnetic core of the microcircuit module in service, cracking of the magnetic core body or the magnetic core bonding interface still occurs from time to time, which brings devastating failures to the product. Therefore, thoroughly solving the assembly problem of cracking of the board-level magnetic core body or the magnetic core bonding surface of the microcircuit module is of great significance for improving the reliability of the microcircuit module.

[0003] Currently, in the assembly methods of board-level magnetic cores, there are the following deficiencies:

[0004] (1) In the existing traditional methods, the board-level magnetic core is often assembled in the PCB board assembly groove without sufficient assembly clearance. When there is a thermal mismatch among the magnetic core, the magnetic core welding adhesive, and the PCB board material, the magnetic core bonding interface is expanded.

[0005] (2) In the existing traditional methods, the board-level magnetic core is directly adhesively assembled in the PCB board assembly groove. The adhesive overflowing at the magnetic core bonding interface will form a firm bond with the side wall of the PCB board assembly groove. During high and low temperature, random vibration, and mechanical shock tests, the magnetic core bonding interface will be torn.

[0006] (3) In the existing traditional methods, when batch-assembling board-level magnetic cores, additional ceramic chips need to be added to control the air gap and inductance, which makes the assembly difficult and the production efficiency low. Summary of the Invention

[0007] To solve the above problems, this application proposes an assembly method and structure of a board-level magnetic core of a microcircuit module, which solves the problem that the magnetic core bonding interface is expanded due to thermal mismatch among the magnetic core, the magnetic core adhesive, and the PCB board material in a high and low temperature environment; solves the problem that when the board-level magnetic core is directly adhesively assembled in the PCB board assembly groove, after the magnetic core adhesive at the magnetic core bonding interface is extruded, it will form an adhesion with the side wall of the PCB board installation groove, and during the subsequent baking and curing process, the adhesive overflowing at the magnetic core bonding interface will form a firm bond with the side wall of the PCB board assembly groove, and during high and low temperature, random vibration, and mechanical shock tests, the magnetic core bonding interface will be torn; at the same time, it also solves the problem that in batch assembly, hard ceramic chips need to be added to control the air gap and inductance, and the magnetic core can only be bonded after bonding the ceramic chips, reducing the assembly difficulty and improving the production efficiency.

[0008] This application is achieved through the following technical solutions:

[0009] This application provides an assembly method and structure for a board-level magnetic core of a microcircuit module. The assembly method includes the following steps:

[0010] (1) Open a board-level magnetic core assembly groove on the PCB board;

[0011] (2) Apply a layer of non-transparent flexible silicone rubber on the side wall of the board-level magnetic core assembly groove;

[0012] (3) Apply a modified magnetic core adhesive on the bonding ends of the board-level upper magnetic core or the board-level lower magnetic core, and press the bonding ends of the board-level upper magnetic core and the board-level lower magnetic core tightly in the board-level magnetic core assembly groove to bond the two together to form a board-level magnetic core body;

[0013] (4) Heat the bonding part of the board-level upper magnetic core and the board-level lower magnetic core to cure the magnetic core adhesive;

[0014] (5) Seal the gap between the board-level magnetic core body and the board-level magnetic core assembly groove;

[0015] (6) Install the PCB board into the microcircuit module housing to complete the assembly of the board-level magnetic core of the microcircuit module.

[0016] Further, in step (1), the distance between the outer side wall of the board-level magnetic core and the inner side wall of the board-level magnetic core assembly groove is 0.2 mm, and the distance between the inner side wall of the upper or lower side of the board-level magnetic core and the upper or lower side of the PCB board is 0.25 mm.

[0017] Further, in step (2), the thickness of the non-transparent flexible silicone rubber applied is 0.05 - 0.1 mm.

[0018] Further, in step (3), the preparation method of the modified magnetic core adhesive is: add glass beads with a mass fraction of 10 - 30% and a particle size of 60 - 150 μm on the basis of the magnetic core adhesive.

[0019] Further, in step (4), before heating the magnetic core adhesive, place soft wood chips with the same surface area as the board-level magnetic core body on the upper and lower surfaces of the board-level magnetic core body, and then clamp the soft wood chips with a clamping clip.

[0020] Further, in step (5), the method for sealing the gap between the board-level magnetic core body and the board-level magnetic core assembly groove is: first paste adhesive paper baffles on the windows on both sides in the long side direction of the board-level magnetic core body, and then apply silicone rubber at some points between the board-level magnetic core body and the upper side of the PCB board to seal the gap between the board-level magnetic core body and the PCB board and the windows of the board-level magnetic core body.

[0021] Further, in step (6), first make a soft pad on the surface of the board-level magnetic core body opposite to the cover plate of the microcircuit module, and then complete the assembly of the cover plate of the microcircuit module.

[0022] Further, the soft pad includes but is not limited to silicone rubber clusters or pads.

[0023] Further, an assembly structure of a board-level magnetic core of a microcircuit module includes a PCB board, a board-level upper magnetic core, and a board-level lower magnetic core. Three board-level magnetic core assembly grooves are opened on the PCB board. A non-transparent flexible silicone rubber layer is provided on the inner side wall of each board-level magnetic core assembly groove. The bonding ends of the board-level upper magnetic core and the board-level lower magnetic core are inserted into the board-level magnetic core assembly grooves, and the bonding end of the board-level upper magnetic core is connected to the bonding end of the board-level lower magnetic core through a modified magnetic core bonding adhesive. A sticker baffle is bonded on the window of the board-level upper magnetic core, and a silicone rubber sealing layer is provided outside the board-level upper magnetic core and the sticker baffle.

[0024] Advantages of the present application: (1) By opening board-level magnetic core assembly grooves on the PCB board that conform to the installation of the board-level magnetic core, in high and low temperature environments, the magnetic core, the magnetic core bonding adhesive, and the PCB board material will not have thermal mismatch, and the phenomenon of the magnetic core bonding interface being bulged open will not occur. And by applying a layer of flexible silicone rubber layer on the inner side wall of the board-level magnetic core assembly groove, after the magnetic core bonding adhesive at the magnetic core bonding interface is extruded, it will not adhere to the side wall of the assembly groove. During the subsequent baking and curing process, the magnetic core bonding interface will not be torn. And a modified magnetic core bonding adhesive is used to connect the board-level upper magnetic core and the board-level lower magnetic core. In batch assembly, there is no need to add hard ceramic chips to control the air gap and inductance, which reduces the assembly difficulty and improves the production efficiency.

[0025] (2) When applying the magnetic core bonding adhesive to bond the magnetic core and heating and curing the magnetic core bonding adhesive in the present invention, a soft wood chip with the same surface area as the magnetic core surface is installed under the clamping clip to protect the magnetic core and make the magnetic core surface bear uniform pressure, preventing the magnetic core body from cracking and being damaged.

[0026] (3) After the magnetic core bonding is completed in the present invention, sticker baffles are pasted on the windows on both sides of the long side direction of the magnetic core, and then silicone rubber is dot-applied for sealing to prevent the silicone rubber from directly entering the magnetic core cavity and having an adverse impact on the strength of the magnetic core bonding surface during the high and low temperature process of the product.

[0027] (4) After the window of the board-level magnetic core is sealed in the present invention, before the PCB board is installed in the microcircuit module housing for cover plate assembly, silicone rubber clusters or pads are made on the magnetic core surface opposite to the cover plate, solving the problem that the magnetic core body is cracked under pressure when the microcircuit module is assembled and used by the user. Description of the Drawings

[0028] Figure 1 Schematic diagram of the overall process of the present invention;

[0029] Figure 2 Schematic diagram of the upper side cross-section structure of the structure of the present invention;

[0030] Figure 3 Side sectional view of the structure of the present invention;

[0031] Figure 4 Schematic diagram of the structure of the assembly groove of the present invention;

[0032] Figure 5 Schematic diagram of the connection structure between the upper core and the lower core on the board level of the present invention;

[0033] Figure 6 Schematic diagram of the window plugging structure of the upper core on the board level of the present invention;

[0034] Figure 7 Schematic diagram of the structure for assembling the cover plate when the PCB board of the present invention is installed in the microcircuit module housing. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0036] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0037] In addition, the descriptions involving "first", "second", etc. in the present application are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0038] Please refer to Figure 1, this application proposes an assembly method for a board-level magnetic core of a microcircuit module, including the following steps:

[0039] (1) Open a board-level magnetic core assembly groove on the PCB board.

[0040] Specifically, as Figure 2 , 3 shown, open a PCB board assembly groove on the PCB board that conforms to the actual installation of the board-level magnetic core. After installing the board-level magnetic core, the length and width of the board-level magnetic core assembly groove should be 0.4 mm larger than the magnetic core, that is, the distance between the outer sidewall of the board-level magnetic core and the inner sidewall of the board-level magnetic core assembly groove is 0.2 mm. In the thickness direction, the height of the internal cavity formed by the board-level upper magnetic core and the board-level lower magnetic core that make up the board-level magnetic core body is 0.5 mm larger than the PCB board thickness, and the distance from the upper sidewall of the internal cavity, specifically the upper surface of the PCB board or the lower sidewall of the internal cavity, to the lower surface of the PCB board is 0.25 mm. This solves the problem in the existing assembly method that the board-level magnetic core is often assembled in the PCB board assembly groove without sufficient assembly clearance, and the magnetic core bonding interface is swollen when there is a thermal mismatch between the magnetic core, the magnetic core welding adhesive, and the PCB board material. By setting a board-level magnetic core body assembly groove with sufficient space, it is convenient for the assembly of the board-level magnetic core.

[0041] (2) Apply a layer of non-transparent flexible silicone rubber on the sidewall of the board-level magnetic core assembly groove

[0042] Specifically, to solve the problem in the existing assembly method that when the board-level magnetic core is directly adhesively assembled in the PCB board assembly groove, the adhesive overflowing at the magnetic core bonding interface will form a firm bond with the sidewall of the PCB board assembly groove, and the magnetic core bonding interface will be torn during high and low temperature, random vibration, and mechanical shock tests. In this embodiment, as Figure 4 shown, pre-treat the board-level magnetic core assembly groove, apply a thin layer of non-transparent flexible silicone rubber with a good visibility of 0.05 - 0.1 mm thick on the sidewall of the board-level magnetic core assembly groove. When the board-level magnetic core is directly adhesively assembled in the PCB board assembly groove, after the magnetic core adhesive at the magnetic core bonding interface is extruded, it will first adhere to the silicone rubber on the board-level magnetic core assembly groove. During the subsequent baking and curing process, during high and low temperature, random vibration, and mechanical shock tests, the adhesive overflowing at the magnetic core bonding interface will not form a firm bond with the sidewall of the board-level magnetic core assembly groove, and the magnetic core bonding interface will not be torn.

[0043] (3) Apply a modified magnetic core adhesive on the bonding end of the board-level upper magnetic core or the board-level lower magnetic core, and press the bonding ends of the board-level upper magnetic core and the board-level lower magnetic core tightly in the board-level magnetic core assembly groove to bond the two together to form a board-level magnetic core body.

[0044] Specifically, in order to solve the problem that in the existing assembly method, in batch assembly of plate-level magnetic cores, additional ceramic sheets need to be added to control the air gap and inductance, the assembly is difficult, and the production efficiency is low, in this embodiment, Figure 5 As shown, the board-level upper magnetic core and the board-level lower magnetic core are connected by modified magnetic core adhesive. The preparation method of the modified magnetic core adhesive is: according to the requirements of air gap and inductance, 10-30% mass fraction of glass beads with a particle size of 60-150μm are added to the traditional magnetic core adhesive. By improving the design of the magnetic core adhesive, the air gap of the magnetic core can be directly controlled to achieve the required inductance after assembly. It solves the problem of adding hard ceramic sheets to control the air gap and inductance in batch assembly, and the magnetic core can only be bonded after the ceramic sheets are bonded, which reduces the difficulty of assembly and improves production efficiency.

[0045] (4) Heat the bonding point between the upper magnetic core and the lower magnetic core to solidify the magnetic core adhesive.

[0046] Specifically, in order to solve the problem that in the existing assembly method, when the magnetic core adhesive is heated and cured, the clip is directly clamped on the surface of the board-level upper magnetic core and the board-level lower magnetic core, which may cause the body of the board-level upper magnetic core or the board-level lower magnetic core to crack and be damaged, in this embodiment, Figure 5 As shown, before heating the magnetic core adhesive, soft wood pieces with the same surface area as the upper side of the board-level upper magnetic core or the lower side of the board-level lower magnetic core are placed on the upper and lower side surfaces of the board-level magnetic core body, and then the soft wood pieces are clamped with clamps to protect the magnetic core and make the surface of the magnetic core bear uniform pressure to prevent the magnetic core body from cracking and damage.

[0047] (5) The gap between the plate-level magnetic core body and the plate-level magnetic core assembly slot is sealed.

[0048] Specifically, in order to solve the problem that in the existing assembly method, after the magnetic core is bonded, in order to prevent the glue in the microcircuit module from entering the magnetic core cavity and affecting the magnetic core bonding interface, the silicone rubber is directly applied to the magnetic core window for blocking, resulting in liquid silicone rubber overflowing into the magnetic core cavity through the magnetic core window, which has an adverse effect on the strength of the magnetic core bonding interface under high and low temperature environments. In this embodiment, Figure 6 As shown, the method for sealing the gap between the board-level magnetic core body and the board-level magnetic core assembly slot is: first, adhesive tape baffles are pasted on the windows on both sides of the long side direction of the board-level magnetic core, and then silicone rubber is applied to the part between the board-level magnetic core and the upper side of the PCB board, that is, the gap between the board-level magnetic core and the PCB board and the outside of the board-level magnetic core window pasted with adhesive tape baffles, so as to seal the gap between the board-level magnetic core body and the PCB board and the window of the board-level magnetic core body. Prevent the silicone rubber from entering the magnetic core cavity and affecting the bonding interface of the magnetic core when the glue is poured in the microcircuit module. And prevent it from causing adverse effects on the strength of the bonding surface of the magnetic core during the high and low temperature process of the product.

[0049] (6) Install the PCB board into the microcircuit module housing to complete the assembly of the board-level magnetic core of the microcircuit module.

[0050] Specifically, in the existing assembly method, due to the high density of product component assembly and the extremely small assembly height space, the distance between the magnetic core body and the inner surface of the cover plate is only 0.1 - 0.3 mm. When the microcircuit module is assembled and used by the user, it will cause the magnetic core body to be directly compressed and cracked. In this embodiment, as Figure 7 shown, after completing the window plugging of the board-level magnetic core, before installing the PCB board into the microcircuit module housing for cover plate assembly, make a silicone rubber mass or gasket on the magnetic core surface opposite to the microcircuit module cover plate, and then assemble the cover plate above the magnetic core surface. It solves the problem that the magnetic core body is compressed and cracked when the microcircuit module is assembled and used by the user.

[0051] The present invention also discloses an assembly structure of a board-level magnetic core of a microcircuit module. The structure includes a PCB board, a board-level upper magnetic core, and a board-level lower magnetic core. Three board-level magnetic core assembly grooves are provided on the PCB board. Non-transparent flexible silicone rubber layers are provided on the inner side walls of each board-level magnetic core assembly groove. The bonding ends of the board-level upper magnetic core and the bonding ends of the board-level lower magnetic core are inserted into the board-level magnetic core assembly grooves, and the bonding ends of the board-level upper magnetic core are connected to the bonding ends of the board-level lower magnetic core through a modified magnetic core bonding adhesive. A sticker baffle is bonded to the window of the board-level upper magnetic core, and a silicone rubber plugging layer is provided outside the board-level upper magnetic core and the sticker baffle.

[0052] Of course, the present application may also have many other implementation manners. Based on this implementation manner, other implementation manners obtained by those of ordinary skill in the art without any creative work belong to the scope protected by the present application.

Claims

1. An assembly method for a board-level magnetic core of a microcircuit module, characterized in that, it includes the following steps: (1) A board-level magnetic core assembly groove is opened on the PCB board; (2) Apply a layer of non-transparent flexible silicone rubber on the side wall of the board-level magnetic core assembly groove; (3) Apply a modified magnetic core adhesive on the bonding ends of the board-level upper magnetic core or the board-level lower magnetic core, and press the bonding ends of the board-level upper magnetic core and the board-level lower magnetic core tightly in the board-level magnetic core assembly groove to bond the two together to form a board-level magnetic core body; (4) Heat the bonding part of the board-level upper magnetic core and the board-level lower magnetic core to cure the magnetic core adhesive; (5) Seal the gap between the board-level magnetic core body and the board-level magnetic core assembly groove; (6) Install the PCB board into the microcircuit module housing to complete the assembly of the board-level magnetic core of the microcircuit module.

2. The assembly method for the board-level magnetic core of a microcircuit module according to claim 1, characterized in that, in step (1), the distance between the outer side wall of the board-level magnetic core and the inner side wall of the board-level magnetic core assembly groove is 0.2 mm, and the distance between the inner side wall of the upper or lower side of the board-level magnetic core and the upper or lower side of the PCB board is 0.25 mm.

3. The assembly method for the board-level magnetic core of a microcircuit module according to claim 1, characterized in that, in step (2), the thickness of the non-transparent flexible silicone rubber applied is 0.05 - 0.1 mm.

4. The assembly method for the board-level magnetic core of a microcircuit module according to claim 1, characterized in that, in step (3), the preparation method of the modified magnetic core adhesive is: add glass beads with a mass fraction of 10 - 30% and a particle size of 60 - 150 μm on the basis of the magnetic core adhesive.

5. The assembly method for the board-level magnetic core of a microcircuit module according to claim 1, characterized in that, in step (4), before heating the magnetic core adhesive, place soft wood pieces with the same surface area as the surface of the board-level magnetic core body on the upper and lower surfaces of the board-level magnetic core body, and then clamp the soft wood pieces with clamping clips.

6. The assembly method for the board-level magnetic core of a microcircuit module according to claim 1, characterized in that, in step (5), the method for sealing the gap between the board-level magnetic core body and the board-level magnetic core assembly groove is: first paste adhesive paper baffles on the windows on both sides in the long side direction of the board-level magnetic core body, and then apply silicone rubber at some points between the board-level magnetic core body and the upper side of the PCB board to seal the gap between the board-level magnetic core body and the PCB board and the windows of the board-level magnetic core body.

7. The assembly method for the board-level magnetic core of a microcircuit module according to claim 1, characterized in that, in step (6), first make a soft pad on the surface of the board-level magnetic core body opposite to the microcircuit module cover plate, and then complete the assembly of the microcircuit module cover plate.

8. The assembly method for the board-level magnetic core of a microcircuit module according to claim 1, characterized in that, the soft pad includes but is not limited to silicone rubber clusters or pads.

9. An assembly structure for a board-level magnetic core of a microcircuit module, characterized in that, It includes a PCB board, an upper board-level magnetic core and a lower board-level magnetic core. Three board-level magnetic core assembly grooves are formed on the PCB board. Non-transparent flexible silicone rubber layers are provided on the inner side walls of each of the board-level magnetic core assembly grooves. The bonding ends of the upper board-level magnetic core and the lower board-level magnetic core are inserted into the board-level magnetic core assembly grooves, and the bonding end of the upper board-level magnetic core is connected to the bonding end of the lower board-level magnetic core through a modified magnetic core adhesive. A sticker baffle is bonded to the window of the upper board-level magnetic core, and a silicone rubber sealing layer is provided on the outside of the upper board-level magnetic core and the sticker baffle.

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