A magnetic core assembly and its preparation method and application

Abstract

The present invention provides a magnetic core assembly and a preparation method and application thereof. The magnetic core assembly comprises a first magnetic core, a bonding layer and a second magnetic core which are arranged in sequence, and the material of the bonding layer comprises glue and alumina powder. The magnetic core assembly provided by the present invention adds alumina powder as an air gap material to the material of the bonding layer, and utilizes the glue to evenly disperse and fix the alumina powder in the bonding layer, thereby making the obtained magnetic core assembly have a higher shear force, a lower risk of falling off, and a lower operating temperature and noise generated during subsequent assembly and use.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors, and in particular relates to a magnetic core assembly and a preparation method and application thereof. Background Art

[0002] Magnetic core structures are widely used in various fields of life, such as low-temperature thermal compensation structures of household refrigerators, automotive temperature sensors, etc. The core components of these structures are magnetic temperature switches with precise temperature control, and the core components of magnetic temperature switches are magnetic core components (including magnetic core structures and magnetic sensitive components). Traditional magnetic core components generally include soft magnets and two hard magnets arranged on both sides of the soft magnets, and the soft magnets and hard magnets are fixed by glue. Due to the different components of soft magnets and hard magnets, the traditional production process is to mold the two hard magnets and the soft magnets separately, and then use glue to bond and assemble them.

[0003] However, the traditional magnetic core structure has many components, including one soft magnet and two hard magnets, which makes assembly difficult and has low production efficiency. At the same time, the presence of glue also has an adverse effect on the magnetic stability of the magnetic core structure, especially at low or high temperatures, which greatly affects the magnetic stability of the magnetic structure and reduces the response speed of the magnetic sensitive temperature control switch.

[0004] CN104900368A discloses an integrated magnetic core structure and a manufacturing method thereof and a magnetic core assembly, including a soft magnetic part and a hard magnetic part arranged at both ends of the soft magnetic part, wherein the soft magnetic part and the hard magnetic part are provided with cavities for placing magnetic sensitive elements, and the soft magnetic part and the hard magnetic part are formed in an integrated manner; the width of the soft magnetic part is smaller than that of the hard magnetic part, so that the side of the magnetic core structure forms a groove that is convenient for magnetizing the hard magnetic part. The magnetic core structure proposed in the invention is formed by the soft magnetic part and the hard magnetic part in an integrated manner, and is magnetized at one time, without the need to magnetize the hard magnetic separately and then glue and assemble, which greatly improves the production efficiency. At the same time, the magnetic core structure of the invention has good performance and strong stability, and can maintain a high magnetic permeability even in the low temperature section or the high temperature section. CN105529128A discloses an inductor and a manufacturing method thereof. The inductor comprises a first soft magnetic core and a second soft magnetic core, and also comprises a bonding material. The bonding material comprises glue and a soft magnetic material. The first soft magnetic core is bonded to the second soft magnetic core through the bonding material. The saturation magnetic field strength of the soft magnetic material is less than or equal to 15 A / m, and the initial magnetic permeability is greater than or equal to 1. The inductor improves the ability of the inductor to suppress ripple and current impact in a small current region.

[0005] However, the traditional core assembly process adjusts the inductance of the product by adding an appropriate amount of assembly glue in the middle of the product and then placing air gap paper of corresponding thickness into the assembly glue. This process will cause the position of the air gap paper to be unable to be fixed, which will lead to uneven air gaps on the entire product surface. The resulting core assembly will have the risk of high temperature rise and high noise during the whole machine test during installation and use after assembly.

[0006] Therefore, developing a magnetic core assembly with very low temperature rise and low noise during installation and use is a technical problem that urgently needs to be solved in the field. Summary of the invention

[0007] In view of the deficiencies in the prior art, the object of the present invention is to provide a magnetic core assembly and a preparation method and application thereof, wherein the magnetic core assembly comprises a first magnetic core, a bonding layer and a second magnetic core arranged in sequence; the material of the bonding layer comprises glue and alumina powder; by adding alumina powder to the material of the bonding layer, the temperature and noise generated by the magnetic core assembly during installation and use after assembly are lower.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a magnetic core assembly, the magnetic core assembly comprising a first magnetic core, a bonding layer, and a second magnetic core arranged in sequence;

[0010] The materials of the bonding layer include glue and aluminum oxide powder.

[0011] The cross-sectional structure diagram of the magnetic core assembly provided by the present invention is as follows Figure 1 As shown, Figure 1 In FIG. 1 , 1 represents the first magnetic core, 2 represents the bonding layer, and 3 represents the second magnetic core; wherein the first magnetic core 1 and the second magnetic core 3 are connected together by the bonding layer 2; the top view of the bonding layer 2 is shown in FIG. Figure 2 As shown, Figure 2 In the figure, 2-1 represents alumina powder, 2-2 represents glue, Figure 2 It can be seen that the alumina powder 2-1 as the air gap material is evenly distributed in the glue 2-2 and is fixed in the bonding layer 2 by the glue 2-2, so that it will not be displaced during subsequent installation and use, thereby reducing the temperature rise of the prepared magnetic core assembly during installation and use after assembly, and generating less noise.

[0012] Preferably, the material of the first magnetic core includes alloy soft magnetic material.

[0013] Preferably, the material of the second magnetic core includes alloy soft magnetic material.

[0014] Preferably, the alloy soft magnetic material includes iron silicon or iron silicon aluminum alloy.

[0015] Preferably, the thickness of the first magnetic core is 10 to 25 mm, for example, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, 22 mm or 24 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0016] Preferably, the thickness of the second magnetic core is 10 to 25 mm, for example, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, 22 mm or 24 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0017] Preferably, the thickness of the adhesive layer is 0.1-0.5 mm, for example, 0.15 mm, 0.18 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.40 mm, 0.45 mm or 0.5 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0018] Preferably, the mass percentage of alumina powder in the material of the bonding layer is 1 to 6%, for example, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5% or 6%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0019] As a preferred technical solution of the present invention, the mass percentage of alumina powder in the material of the bonding layer is 1-6%, which can minimize the temperature rise of the prepared magnetic core assembly and generate the smallest noise; on the one hand, if the amount of alumina powder added to the bonding layer is too low, it will lead to uneven air gaps, and there will be risks of noise and temperature rise; on the other hand, if the amount of alumina powder added to the bonding layer is too high, the bonding strength between the first magnetic core and the second magnetic core will decrease, increasing the risk of noise and temperature rise during use.

[0020] Preferably, the glue is epoxy resin glue.

[0021] Preferably, the D50 particle size of the alumina powder is 0.1-0.5 mm, for example, 0.15 mm, 0.18 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.40 mm, 0.45 mm or 0.5 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0022] As a preferred technical solution of the present invention, the aluminum oxide powder with a D50 particle size of 0.1 to 0.5 mm is selected and added to the bonding layer in order to obtain a magnetic core assembly with the lowest temperature rise and the lowest noise. On the one hand, if the D50 particle size of the aluminum oxide powder added to the bonding layer is less than 0.1 mm, the magnetic properties of the magnetic core assembly will not meet the requirements; on the other hand, if the D50 particle size of the aluminum oxide powder added to the bonding layer is greater than 0.5 mm, the bonding strength will decrease, increasing the risk of noise and temperature rise.

[0023] In a second aspect, the present invention provides a method for preparing the magnetic core assembly according to the first aspect, the method comprising the following steps:

[0024] (1) mixing alumina powder and glue to obtain a bonding layer material;

[0025] (2) coating the adhesive layer material obtained in step (1) on the surface of the first magnetic core, and attaching the second magnetic core to obtain the magnetic core assembly.

[0026] Preferably, after the laminating of the second magnetic core is completed, a curing step is also included.

[0027] Preferably, the curing temperature is 140-160°C, for example, 142°C, 144°C, 146°C, 148°C, 150°C, 152°C, 154°C, 156°C or 158°C.

[0028] In a third aspect, the present invention provides an electronic product, comprising the magnetic core assembly as described in the first aspect.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The magnetic core assembly provided by the present invention comprises a first magnetic core, a bonding layer and a second magnetic core which are arranged in sequence, and the material of the bonding layer comprises glue and alumina powder; the magnetic core assembly provided by the present invention adds alumina powder as an air gap material to the material of the bonding layer, and uses the glue to evenly disperse and fix the alumina powder in the bonding layer, so that the temperature of the obtained magnetic core assembly is low during subsequent assembly and use, and the noise generated is low; specifically, the use temperature of the magnetic core assembly provided by the present invention after installation is 145-156°C, the noise generated is 65-76dB, and the shear force is 532-659kg, indicating that the strength of the bonding layer is high, and the risk of falling off after installation is low. At the same time, the inductance of the magnetic core assembly is 62-68μH at 300A, which meets the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic cross-sectional structure diagram of a magnetic core assembly provided in Example 1;

[0032] Figure 2 is a schematic diagram of the top view of the bonding layer in Example 1;

[0033] Figure 3 A schematic diagram of the top view of the bonding layer in the magnetic core assembly provided in Comparative Example 2;

[0034] Among them, 1-first magnetic core, 2-adhesive layer, 3-second magnetic core, 2-1-alumina powder, 2-2-glue, 4-1 air gap paper. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0036] Example 1

[0037] A magnetic core assembly, the cross-sectional structure diagram of which is as follows Figure 1 As shown, it includes a first magnetic core 1, a bonding layer 2 and a second magnetic core 3;

[0038] The material of the first magnetic core 1 is iron silicon, and the thickness is 20 mm;

[0039] The thickness of the adhesive layer 2 is 0.25 mm. The top view of the adhesive layer 2 is shown in FIG. Figure 2 As shown, it is composed of glue 2-2 and alumina powder 2-1 uniformly dispersed in the glue 2-2, wherein the mass ratio of glue 2-2 to alumina powder 2-1 is 98:2, glue 2-2 is epoxy resin glue (Huitian, 6065), and D50 of alumina powder 2-1 is 0.15 mm;

[0040] The material of the second magnetic core 3 is iron silicon, and the thickness is 20 mm;

[0041] The method for preparing the magnetic core assembly provided in this embodiment comprises the following steps:

[0042] (1) mixing epoxy resin glue and alumina powder to obtain a bonding layer material;

[0043] (2) Coating the bonding layer material obtained in step (1) on the surface of the first magnetic core, bonding the second magnetic core, and curing at 150° C. for 60 minutes to obtain the magnetic core assembly.

[0044] Example 2

[0045] A magnetic core assembly, the cross-sectional structure of which is the same as that of embodiment 1, comprising a first magnetic core, a bonding layer and a second magnetic core;

[0046] Wherein, the material of the first magnetic core is iron silicon, and the thickness is 20mm;

[0047] The thickness of the bonding layer is 0.15 mm. The top view structure of the bonding layer is the same as that of Example 1, and is composed of glue and alumina powder uniformly dispersed in the glue, wherein the mass ratio of the glue to the alumina powder is 99:1, the glue is epoxy resin glue (Huitian, 6065), and the D50 of the alumina powder is 0.2 mm;

[0048] The material of the second magnetic core is iron silicon, and the thickness is 20mm;

[0049] The method for preparing the magnetic core assembly provided in this embodiment comprises the following steps:

[0050] (1) mixing epoxy resin glue and alumina powder to obtain a bonding layer material;

[0051] (2) Coating the bonding layer material obtained in step (1) on the surface of the first magnetic core, bonding the second magnetic core, and curing at 150° C. for 60 minutes to obtain the magnetic core assembly.

[0052] Example 3

[0053] A magnetic core assembly, the cross-sectional structure of which is the same as that of embodiment 1, comprising a first magnetic core, a bonding layer and a second magnetic core;

[0054] The material of the first magnetic core is iron silicon, and the thickness is 25 mm;

[0055] The thickness of the bonding layer is 0.22 mm, and the top view structure of the bonding layer is the same as that of Example 1, and is composed of glue and alumina powder uniformly dispersed in the glue, wherein the mass ratio of the glue to the alumina powder is 97:3, the glue is epoxy resin glue (Huitian, 6065), and the D50 of the alumina powder is 0.3 mm;

[0056] The material of the second magnetic core is iron silicon, and the thickness is 25mm;

[0057] The method for preparing the magnetic core assembly provided in this embodiment comprises the following steps:

[0058] (1) mixing epoxy resin glue and alumina powder to obtain a bonding layer material;

[0059] (2) Coating the bonding layer material obtained in step (1) on the surface of the first magnetic core, bonding the second magnetic core, and curing at 150° C. for 60 minutes to obtain the magnetic core assembly.

[0060] Example 4

[0061] A magnetic core assembly, which is different from Example 1 only in that the mass ratio of glue and alumina powder in the bonding layer is 90:10, and other structures, parameters and preparation methods are the same as those in Example 1.

[0062] Example 5

[0063] A magnetic core assembly, which is different from Example 1 only in that the mass ratio of glue and alumina powder in the bonding layer is 99.5:0.5, and other structures, parameters and preparation methods are the same as those in Example 1.

[0064] Example 6

[0065] A magnetic core assembly, which is different from Example 1 only in that the D50 particle size of the aluminum oxide powder is 0.55 mm, and other structures, parameters and preparation methods are the same as those of Example 1.

[0066] Example 7

[0067] A magnetic core assembly, which is different from Example 1 only in that the D50 particle size of the alumina powder is 0.6 mm, and other structures, parameters and preparation methods are the same as those of Example 1.

[0068] Comparative Example 1

[0069] A magnetic core assembly, which differs from Example 1 only in that the bonding layer does not contain alumina powder and is entirely composed of epoxy resin glue. Other structures, parameters and preparation methods are the same as those of Example 1.

[0070] Comparative Example 2

[0071] A magnetic core assembly, the cross-sectional structure of which is the same as that of embodiment 1, comprising a first magnetic core, a bonding layer and a second magnetic core;

[0072] Wherein, the material of the first magnetic core is iron silicon, and the thickness is 20mm;

[0073] The thickness of the bonding layer is 0.25 mm, and the top view structure of the bonding layer is as follows: Figure 3 As shown, it is composed of glue 2-2 and air gap sheet 4-1, wherein the glue 2-2 is epoxy resin glue (Huitian, 6065), and the air gap sheet 4-1 is PET polyester film;

[0074] The material of the second magnetic core is iron silicon, and the thickness is 20mm;

[0075] The preparation method of the magnetic core assembly provided in this comparative example includes: coating epoxy resin glue on the surface of the first magnetic core, placing an air gap sheet, bonding the second magnetic core, and curing at 150° C. for 60 minutes to obtain the magnetic core assembly.

[0076] Performance Testing:

[0077] (1) Temperature after installation: Use a temperature-sensitive wire to attach the magnetic core assembly to the pasting position, and use a thermometer to monitor the actual temperature during use;

[0078] (2) Noise after installation: First, heat the core assembly to the operating temperature, then place the core assembly in the closed box of the noise tester, connect the test line to the decibel analyzer, and record the actual decibel value;

[0079] (3) Risk of falling off: Place the core assembly into the test fixture and use a strength tester to test the shear force;

[0080] (4) Inductance: Put the test coil on the core assembly, connect the test instrument chuck, and use the DPG test instrument for testing. The test current is 300A.

[0081] The magnetic core assemblies provided in Examples 1 to 7 and Comparative Examples 1 to 2 were tested according to the above test method. The test results are shown in Table 1:

[0082] Table 1

[0083] Operating temperature(℃) Noise(dB) Shear force(kg) Sensitivity(μH) Example 1 145 65 635 68 Example 2 148 67 586 67.9 Example 3 150 70 569 66.8 Example 4 156 76 532 66 Example 5 152 66 596 62 Example 6 151 72 468 67 Example 7 153 73 465 66 Comparative Example 1 153 67 589 60 Comparative Example 2 172 82 569 67

[0084] It can be seen from the data in Table 1 that the magnetic core assembly provided by the present invention has a lower temperature rise when in use, generates less noise, and has a larger shear force, indicating that the bonding is firm and not prone to falling off, and the inductance at 300A also meets the requirements.

[0085] Specifically, the core assemblies obtained in Examples 1 to 7 have a use temperature of 145 to 156° C. after installation, generate noise of 65 to 76 dB, have a shear force of 465 to 659 kg, and have an inductance of 62 to 68 μH at 300 A.

[0086] By comparing Example 1 and Comparative Example 1, it can be found that if no alumina powder is added to the bonding layer, the inductance of the obtained magnetic core assembly will be greatly reduced and cannot meet the use requirements.

[0087] By comparing Example 1 and Comparative Example 2, it can be found that the conventional magnetic core assembly has a high temperature and generates a large noise after being installed and used.

[0088] Further comparison of Example 1 and Examples 4 to 5 shows that if the amount of alumina powder added to the bonding layer is higher than the preferred range specified in the present invention, the shear force of the magnetic core assembly will decrease, the bonding strength will be lower, and the shedding rate will still increase significantly; and if the amount of glue added to the bonding layer is higher than the preferred range specified in the present invention, the inductance of the magnetic core assembly will decrease.

[0089] Further comparison of Examples 6 to 7 shows that the particle size of the aluminum oxide powder in the bonding layer is not within the preferred range defined in the present invention, which also results in a decrease in the shear force of the obtained magnetic core assembly, an increase in noise, and an increase in the risk of falling off.

[0090] The applicant declares that the present invention illustrates a magnetic core assembly and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A magnetic core assembly, characterized in that: The magnetic core assembly comprises a first magnetic core, a bonding layer and a second magnetic core which are arranged in sequence; The material of the bonding layer is composed of glue and alumina powder; the alumina powder is evenly distributed in the glue as the air gap material; The mass percentage of aluminum oxide powder in the material of the bonding layer is 1 to 6%; The D50 particle size of the alumina powder is 0.1-0.5 mm.

2. The magnetic core assembly according to claim 1, characterized in that: The material of the first magnetic core includes alloy soft magnetic material.

3. The magnetic core assembly according to claim 1, characterized in that: The material of the second magnetic core includes alloy soft magnetic material.

4. The magnetic core assembly according to claim 2 or 3, characterized in that: The alloy soft magnetic material includes iron silicon or iron silicon aluminum alloy.

5. The magnetic core assembly according to claim 1, characterized in that: The thickness of the first magnetic core is 10-25 mm.

6. The magnetic core assembly according to claim 1, characterized in that: The thickness of the second magnetic core is 10-25 mm.

7. The magnetic core assembly according to claim 1, characterized in that: The thickness of the bonding layer is 0.1-0.5 mm.

8. The magnetic core assembly according to claim 1, characterized in that: The glue is epoxy resin glue.

9. A method for preparing a magnetic core assembly according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: (1) mixing alumina powder and glue to obtain a bonding layer material; (2) coating the adhesive layer material obtained in step (1) on the surface of the first magnetic core, and attaching the second magnetic core to obtain the magnetic core assembly.

10. The preparation method according to claim 9, characterized in that: After the second magnetic core is attached, a curing step is also included.

11. The preparation method according to claim 10, characterized in that: The curing temperature is 140-160°C.

12. An electronic product, characterized in that: The electronic product comprises the magnetic core assembly according to any one of claims 1 to 8.

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