Integrated production process of single-air-gap magnetic core and single-air-gap magnetic core

Abstract

The invention relates to the field of magnetic device magnetic cores, and discloses an integrated production process of a single-air-gap magnetic core and the single-air-gap magnetic core. An integrated production process of a single-air-gap magnetic core comprises the following steps that S1, an integrated magnetic core is prepared, and the integrated magnetic core is ground to be flat; s2, preparing an air gap layer on the surface of one side of the integrated magnetic core to prepare an integrated air gap magnetic core; s3, grinding the surface of the air gap layer of the integrated air gap magnetic core; and S4, the integrated air-gap magnetic core is cut according to the required magnetic core size, and the single-air-gap magnetic core is manufactured. According to the integrated production process, the problems of glue overflowing and inaccurate magnetic core positioning in the prior art are solved, the integrated production process is suitable for continuous production of magnetic cores of different specifications and sizes in the industry, and the precision of the manufactured single-air-gap magnetic cores is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of magnetic core of magnetic device, and particularly relates to an integrated production process of single air gap magnetic core and single air gap magnetic core. BACKGROUND

[0002] The single air gap magnetic core refers to a magnetic core structure in which a single air gap is arranged in the magnetic core, and is mainly used for adjusting the magnetic permeability, improving the inductance performance or reducing the risk of magnetic saturation. The air gap is usually formed by cutting or leaving a gap in the middle of the magnetic core, such as the "I" part of the EI type magnetic core or the notch of the ring type magnetic core. This structure can increase the magnetic resistance, thereby adjusting the magnetic flux path and affecting parameters such as inductance and saturation current. The single air gap magnetic core is widely used in devices such as switching power supply, inverter and high-frequency transformer.

[0003] The single air gap magnetic core in the prior art mainly has the following two preparation processes: the first is to add air gap glue on the magnetic core for curing and bonding to form a fixed air gap layer, and the air gap glue contains high-precision spherical inorganic powder or organic microspheres with a particle size distribution, but the particle size of the spherical powder required is different for different sizes of the air gap layer. The difficulty of this processing method lies in the preparation and grading of the high-precision spherical powder; the second is to paste an air gap sheet such as a ceramic sheet between the magnetic cores, and the two sides of the air gap sheet need to be coated with adhesive. Although this preparation process avoids the grading of high-precision spherical powder, the processing difficulty of high-precision air gap sheet is relatively large.

[0004] Since the volume of the magnetic core is relatively small, the coating amount of the adhesive in the above two preparation processes is not easy to control, and problems such as glue overflow or unstable bonding are prone to occur; when the air gap sheet is pasted, the alignment is not accurate, thereby reducing the precision of the single air gap magnetic core. Moreover, the above two preparation processes are for the processing and production between single magnetic cores, which is not conducive to industrialized mass production, and it is difficult to realize production automation for different specifications and models of single air gap magnetic cores. SUMMARY

[0005] In order to solve the problems of the above preparation process for preparing the single air gap magnetic core, the precision of the prepared single air gap magnetic core is low, and it is not conducive to industrialized continuous production, the present application provides an integrated production process of single air gap magnetic core and single air gap magnetic core.

[0006] In a first aspect, the present application provides an integrated production process of single air gap magnetic core, which adopts the following technical solution: An integrated production process of single air gap magnetic core, comprising the following steps: S1, preparing an integrated magnetic core and performing a grinding treatment on the integrated magnetic core; S2, preparing an air gap layer on one side surface of the integrated magnetic core to obtain an integrated air gap magnetic core; S3, grinding the surface of the integrated air gap magnetic core air gap layer; S4, cutting the integrated air gap magnetic core according to the required magnetic core size to obtain a single air gap magnetic core.

[0007] By adopting the above technical scheme, the step S1 of grinding treatment ensures the flatness of the surface of the magnetic core, which can improve the stability of the subsequent air gap layer and the precision of the obtained single air gap magnetic core; the step S2 of preparing the air gap layer on one side surface of the integrated magnetic core to obtain the integrated air gap magnetic core, the large-area air gap layer can be more stably attached to the integrated magnetic core; the step S3 of grinding the surface of the integrated air gap magnetic core air gap layer can improve the flatness of the air gap layer, and the grinding can thin the air gap layer to the required thickness, improving the size precision of the single air gap magnetic core; the step S4 of cutting the integrated air gap magnetic core according to the required magnetic core size to obtain a single air gap magnetic core, which can obtain single air gap magnetic cores meeting different specification requirements. The integrated production process of the present application solves the problems of easy overflow and inaccurate positioning of the magnetic core in the existing process, improves the precision of the single air gap magnetic core, is suitable for continuous production of magnetic cores of different specifications and sizes in industry, and can be widely applied in the fields of switching power supply, inverter and high-frequency transformer.

[0008] Preferably, the air gap layer is prepared by silk screen printing, roller coating, PVD or chemical vapor deposition.

[0009] By adopting the above technical scheme, the air gap layer is prepared by silk screen printing process, which can realize accurate thickness control and is suitable for mass production; it is prepared by roller coating process, which can be quickly and uniformly coated, improving the production efficiency; it is prepared by PVD, which can form a high-quality and dense air gap layer in a high-temperature and high-vacuum environment, enhancing the performance of the air gap layer; it is prepared by chemical vapor deposition, which can be carried out at low temperature and can accurately control the structure of the air gap layer, improving the purity and uniformity of the air gap layer. These preparation processes of the air gap layer solve the problems of easy overflow and inaccurate positioning of the magnetic core in the existing process, are suitable for continuous production of magnetic cores of different specifications and sizes in industry, and the precision of the obtained single air gap magnetic core is high.

[0010] Preferably, the air gap layer is a silicon dioxide layer prepared by chemical vapor deposition.

[0011] By adopting the above technical scheme, the silicon dioxide layer prepared by chemical vapor deposition is used as the air gap layer, which has stable chemical properties and can improve the stability and durability of the air gap layer, avoiding the performance change of the air gap layer due to the influence of external environmental factors, thereby improving the performance stability of the single air gap magnetic core; and the chemical vapor deposition method can accurately control the thickness and uniformity of the silicon dioxide layer, has good hardness and support, is convenient for subsequent cutting, and is conducive to improving the precision of the single air gap magnetic core.

[0012] Preferably, the air gap layer is made by curing epoxy adhesive or polyurethane adhesive.

[0013] By adopting the above technical solution, the air gap layer is made by curing epoxy adhesive or polyurethane adhesive. The epoxy adhesive has good bonding performance, chemical stability and mechanical strength, can firmly combine the air gap layer with the magnetic core, ensure the stability of the single air gap magnetic core structure, and can resist certain chemical corrosion, prolong the service life of the magnetic core. The polyurethane adhesive has good flexibility and elasticity, can buffer the vibration and impact of the magnetic core during use, reduce the risk of damage to the magnetic core, and its curing process is relatively flexible. After curing, it can also provide a little toughness, which is conducive to subsequent slitting, improves the efficiency of slitting, and thus improves the accuracy of the prepared single air gap magnetic core.

[0014] Preferably, the curing temperature of the epoxy adhesive and the polyurethane adhesive is 100-200℃, and the curing time is 10-50min.

[0015] By adopting the above technical solution, the optimal curing temperature and curing time can make the epoxy adhesive and polyurethane adhesive fully cured, ensure the stability and firmness of the air gap layer, avoid the problem of unstable bonding caused by insufficient curing, and thus improve the accuracy of the single air gap magnetic core.

[0016] Preferably, the epoxy adhesive and the polyurethane adhesive both contain inorganic fillers, and the content of the inorganic fillers is 20-85wt%.

[0017] By adopting the above technical solution, the addition of inorganic fillers with a content of 20-85wt% in the epoxy adhesive and polyurethane adhesive can effectively increase the hardness and stability of the air gap layer, improve the reliability of the air gap layer, and thus improve the overall performance of the single air gap magnetic core. Preferably, the content of the inorganic fillers is 40-50wt%. If the content of the inorganic fillers is too low, the overall hardness of the air gap layer is too soft, which is not conducive to subsequent slitting, and will instead reduce the accuracy of the prepared single air gap magnetic core. If the content of the inorganic fillers is too high, the hardness is too large, which is also not conducive to the lamination.

[0018] Preferably, the inorganic fillers are one or a combination of fumed silica, aluminum oxide, and kaolin.

[0019] By adopting the above technical solution, fumed silica has high specific surface area, high purity and good dispersibility, which can enhance the stability and uniformity of the air gap layer; aluminum oxide has high hardness, which can improve the mechanical properties of the air gap layer; kaolin has good plasticity and chemical stability, which is helpful for the molding and long-term use stability of the air gap layer. The comprehensive use of these inorganic fillers can improve the performance of the air gap layer, and thus improve the accuracy and quality of the single air gap magnetic core, which is conducive to the integrated production of the single air gap magnetic core.

[0020] Preferably, the inorganic filler is a pretreated inorganic filler prepared from the following raw materials by weight: inorganic filler 100-120 parts, 3-isocyanate propyl trimethoxysilane 1-2 parts, triphenylmethane triisocyanate 2-4 parts, trimethylolpropane triglycidyl ether 1-2 parts, dodecyl glycidyl ether 0.5-1.5 parts.

[0021] By adopting the above technical solution, the content of the inorganic filler in the polyurethane adhesive and the epoxy resin adhesive is high. If the inorganic filler is directly added to the resin system, the inorganic filler is very easy to agglomerate and difficult to disperse. Therefore, the inorganic filler is further pretreated in the present application, so that the inorganic filler can be uniformly dispersed in the less resin system, and the air gap layer with good flexibility and bonding stability can be formed, so that the air gap layer is not easy to fall off during the use of the magnetic core.

[0022] The inorganic filler is pretreated by using 3-isocyanate propyl trimethoxysilane, triphenylmethane triisocyanate, trimethylolpropane triglycidyl ether and dodecyl glycidyl ether. The 3-isocyanate propyl trimethoxysilane can enhance the interfacial bonding force between the inorganic filler and the organic adhesive, improve the bonding strength and durability of the air gap layer; the triphenylmethane triisocyanate can increase the crosslinking density of the adhesive, improve the hardness and heat resistance of the air gap layer; the trimethylolpropane triglycidyl ether can improve the flexibility and chemical corrosion resistance of the adhesive; the dodecyl glycidyl ether can help to reduce the viscosity of the adhesive, improve its fluidity and construction performance. The synergistic effect of these raw materials can improve the surface properties of the inorganic filler, enhance its compatibility and bonding force with the epoxy adhesive or polyurethane adhesive, improve the stability and uniformity of the air gap layer, and further improve the precision and performance of the single air gap magnetic core.

[0023] Preferably, the thickness of the air gap layer is 5-150µm.

[0024] By adopting the above technical solution, the thickness of the air gap layer can be adjusted according to the needs of the prepared single air gap magnetic core, which can better adjust the magnetic permeability, improve the inductance performance and reduce the risk of magnetic saturation, and at the same time, the magnetic flux path can be precisely adjusted, which affects the inductance, saturation current and other parameters, improves the precision of the single air gap magnetic core, and the air gap layer with the thickness range is convenient for the implementation of integrated production process, which is beneficial to industrial continuous production.

[0025] The thickness of the air gap layer of the present application can be 5µm, 10µm, 20µm, 25µm, 50µm, 80µm, 100µm, 120µm or 150µm, which can be selected according to the size and specification of the prepared single air gap magnetic core.

[0026] In a second aspect, the present application provides a single air gap magnetic core, which adopts the following technical solution: A single air gap magnetic core is prepared by the integrated production process of the single air gap magnetic core, and the single air gap magnetic core is composed of a single magnetic core and an air gap layer.

[0027] By adopting the above technical solution, the single air gap magnetic core of the present application has good magnetic performance, and the air gap layer and the single magnetic core are stably attached with high positioning accuracy.

[0028] In summary, the present application includes at least one of the following beneficial technical effects: 1. By preparing an integrated magnetic core and grinding, preparing an air gap layer, grinding the surface of the air gap layer, and cutting the integrated air gap magnetic core, the problems of easy overflow and inaccurate positioning of the magnetic core in the existing process are solved, and the precision of the single air gap magnetic core is improved.

[0029] 2. The air gap layer can be prepared by various processes such as silk printing, roller coating, PVD or chemical vapor deposition, and the appropriate preparation process can be selected flexibly according to different needs to adapt to different production scenes and requirements.

[0030] 3. The inorganic filler is pretreated by using 3-isocyanate propyl trimethoxysilane, triphenylmethane triisocyanate, trimethylolpropane triglycidyl ether, and dodecyl glycidyl ether, and epoxy adhesive and polyurethane adhesive are prepared, so that the prepared air gap layer has good flexibility and bonding stability, and is not prone to falling off after long-term use, which helps to further improve the precision and stability of the single air gap magnetic core. DETAILED DESCRIPTION

[0031] The present application will be further described in detail below in combination with examples. EXAMPLE Example 1

[0032] Example 1 discloses an integrated production process of a single air gap magnetic core, which includes the following steps: S1, preparing an integrated magnetic core, and using a precision grinding device to grind and process two reference surfaces of the integrated magnetic core; S2, preparing a silicon dioxide air gap layer on one side surface of the integrated magnetic core using chemical vapor deposition method to obtain an integrated air gap magnetic core; S3, grinding the surface of the air gap layer of the integrated air gap magnetic core using a precision grinding device; S4, cutting the integrated air gap magnetic core according to the required magnetic core size to obtain a single air gap magnetic core; the single air gap magnetic core obtained in this embodiment is composed of an air gap layer and a single magnetic core, and the thickness of the air gap layer is 10±3 µm, preferably, the thickness of the air gap layer in this embodiment is 10 µm. Example 2

[0033] Example 2 differs from Example 1 in that the air gap layer is prepared by using epoxy adhesive to cure in the S2 step, and the thickness of the air gap layer of the single air gap magnetic core prepared is 25±5 µm, preferably, the thickness of the air gap layer in this embodiment is 25 µm, and the rest is the same as Example 1. The curing temperature of the epoxy adhesive is 140°C, and the curing time is 20 min. The epoxy adhesive is composed of 55 wt% epoxy resin, 40 wt% inorganic filler and 5 wt% curing agent, the epoxy resin is bisphenol A type epoxy resin: Balin Petrochemical E44; the inorganic filler is fumed silica with a particle size of 100 nm; the curing agent is composed of polyether amine and isophorone diamine with a weight ratio of 3:1, and the molecular weight of the polyether amine is 400. Example 3

[0034] Example 3 differs from Example 1 in that the air gap layer is prepared by using polyurethane adhesive to cure in the S2 step, and the thickness of the air gap layer of the single air gap magnetic core prepared is 50±10 µm, preferably, the thickness of the air gap layer in this embodiment is 50 µm, and the rest is the same as Example 1. The curing temperature of the polyurethane adhesive is 100°C, and the curing time is 50 min. The polyurethane adhesive is composed of 32 wt% polyurethane resin, 50 wt% inorganic filler, 10 wt% ethyl acetate and 8 wt% curing agent, the polyurethane resin is Arakawa polyurethane resin F-206X, the inorganic filler is composed of fumed silica and aluminum trioxide with a weight ratio of 2:1, the particle size of the fumed silica is 50 nm, the particle size of the aluminum trioxide is 100 nm, and the curing agent is isocyanate HT100 curing agent. Example 4

[0035] Example 4 differs from Example 3 in that the inorganic filler in Example 4 is a pretreated filler, which is prepared by the following steps: 0.1 kg of 3-isocyanate propyl trimethoxysilane, 0.4 kg of triphenylmethane triisocyanate, 0.1 kg of trimethylolpropane triglycidyl ether and 0.15 kg of dodecyl glycidyl ether are added to 10 kg of inorganic filler, and kneading is carried out at a temperature of 100°C, and the kneading time is 60 min, to prepare the pretreated filler, and the rest is the same as Example 3. Example 5

[0036] Example 5 differs from Example 4 in that 0.15 kg of 3-isocyanatopropyl trimethoxysilane, 0.3 kg of triphenylmethane triisocyanate, 0.15 kg of trimethylolpropane triglycidyl ether, and 0.1 kg of dodecyl glycidyl ether are added to 11 kg of inorganic filler, kneaded at a temperature of 110°C, and kneaded for 50 min to produce a pretreated filler, and the rest is the same as Example 4. Example 6

[0037] Example 6 differs from Example 4 in that 0.2 kg of 3-isocyanatopropyl trimethoxysilane, 0.2 kg of triphenylmethane triisocyanate, 0.2 kg of trimethylolpropane triglycidyl ether, and 0.05 kg of dodecyl glycidyl ether are added to 12 kg of inorganic filler, kneaded at a temperature of 120°C, and kneaded for 40 min to produce a pretreated filler, and the rest is the same as Example 4. Example 7

[0038] Example 7 differs from Example 4 in that dodecyl glycidyl ether is replaced with an equal amount of trimethylolpropane triglycidyl ether, and the rest is the same as Example 4. Example 8

[0039] Example 8 differs from Example 4 in that triphenylmethane triisocyanate is replaced with an equal amount of 3-isocyanatopropyl trimethoxysilane, and the rest is the same as Example 4. Example 9

[0040] Example 9 differs from Example 4 in that 3-isocyanatopropyl trimethoxysilane is replaced with an equal amount of vinyl trimethoxysilane, and the rest is the same as Example 4. Comparative Example

[0041] Comparative Example 1 Comparative Example 1 differs from Example 3 in that the polyurethane adhesive is directly coated on the surface of the single magnetic core, and cured at a temperature of 100°C for 50 min to produce a single air gap magnetic core.

[0042] Comparative Example 2 Comparative Example 2 differs from Example 3 in that the polyurethane adhesive is directly coated on the surface of the single magnetic core, and a ceramic sheet with a thickness of 50 µm is adhered to the surface of the single magnetic core, and cured at a temperature of 100°C for 50 min to produce a single air gap magnetic core. Performance Test

[0043] The following performance tests were conducted on the single air gap magnetic cores produced in Examples 1-9 and Comparative Examples 1-2: 1. Precision test of single air gap magnetic core: Extract 3 single air gap magnetic core, using full automatic image measuring instrument to detect the size of single air gap magnetic core, the width tolerance of air gap layer of single air gap magnetic core is ±5%, record the average width tolerance of 3 single air gap magnetic cores and keep one decimal place, test and record the test results; 2. Test of adhesion stability of air gap layer: Place the single air gap magnetic core in the condition of 85℃ temperature and 85% humidity, place for 1008h, restore to 25℃, then carry out drop test, free drop from 1.5m height to the surface of wood board, cycle drop for 20 times, observe whether the air gap layer falls off or cracks, and test the inductance value of single air gap magnetic core before and after, the inductance value change rate less than 3% is qualified; The following are the performance test data of single air gap magnetic cores prepared in examples 1-9 and comparative examples 1-2, see table 1 below.

[0044] Table 1 Performance data table of single air gap magnetic cores prepared in examples 1-9 and comparative examples 1-2

[0045] Combined with examples 1-3 and comparative examples 1-2 and table 1, it can be concluded that the single air gap magnetic cores prepared by using the integrated process of the application have good size precision, and the width tolerance is within ±5%, while the width tolerance of the single air gap magnetic cores prepared in comparative example 1 and comparative example 2 is ±10% and ±18% respectively.

[0046] Combined with examples 3 and examples 4-9 and table 1, it can be concluded that when epoxy adhesive or polyurethane adhesive is used to cure the preparation of air gap layer, the adhesion stability of air gap layer and single magnetic core can be significantly improved by further pretreating inorganic fillers, and the inductance stability of the prepared single air gap magnetic core is good after the test of heat and humidity and drop, and the air gap layer will not fall off and crack. Combined with examples 4-6 and examples 7-9, it can be concluded that by using 3-isocyanate propyl trimethoxysilane, triphenyl methane triisocyanate, trimethylolpropane triglycidyl ether and dodecyl glycidyl ether to pretreat inorganic fillers in a specific ratio, the inductance value change rate of the prepared single air gap magnetic core is within 3%, which is qualified; while changing the components and ratio of 3-isocyanate propyl trimethoxysilane, triphenyl methane triisocyanate, trimethylolpropane triglycidyl ether and dodecyl glycidyl ether, the inductance change rate of the prepared single air gap magnetic core increases, and the air gap layer appears edge separation.

[0047] The specific embodiments are only an explanation of the application, which is not a limitation of the application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as it is within the scope of the claims of the application, it is protected by the patent law.

Claims

1. An integrated production process of a single air gap magnetic core, characterized by, The method comprises the following steps: S1, preparing an integrated magnetic core and performing a grinding treatment on the integrated magnetic core; S2, preparing an air gap layer on one side surface of the integrated magnetic core to obtain an integrated air gap magnetic core; S3, grinding the surface of the air gap layer of the integrated air gap magnetic core; S4, cutting the integrated air gap magnetic core according to the required magnetic core size to obtain a single air gap magnetic core.

2. The integrated production process of a single air gap magnetic core according to claim 1, wherein, The air gap layer is prepared by silk printing, roller coating, PVD or chemical vapor deposition.

3. The integrated production process of a single air-gap magnetic core according to claim 2, characterized in that, The air gap layer is a silicon dioxide layer prepared by chemical vapor deposition.

4. The integrated production process of a single air-gap magnetic core according to claim 2, wherein, The air gap layer is prepared by curing an epoxy adhesive or a polyurethane adhesive.

5. The integrated production process of a single air-gap magnetic core according to claim 4, characterized in that, The curing temperature of the epoxy adhesive and the polyurethane adhesive is 100-200°C, and the curing time is 10-50 min.

6. The integrated production process of a single air-gap magnetic core according to claim 4, characterized in that, Both the epoxy adhesive and the polyurethane adhesive contain inorganic fillers, and the content of the inorganic fillers is 20-85wt%.

7. The integrated production process of a single air-gap magnetic core according to claim 6, characterized in that, The inorganic fillers are one or a combination of fumed silica, aluminum trioxide and kaolin.

8. The integrated production process of a single air-gap magnetic core according to claim 7, characterized in that, The inorganic fillers are pretreated inorganic fillers prepared from the following raw materials: inorganic fillers 100-120 parts, 3-isocyanate propyl trimethoxysilane 1-2 parts, triphenylmethane triisocyanate 2-4 parts, trimethylolpropane triglycidyl ether 1-2 parts, and dodecyl glycidyl ether 0.5-1.5 parts.

9. The integrated production process of a single air-gap magnetic core according to any one of claims 1-8, characterized in that, The thickness of the air gap layer is 5-150µm.

10. A single air gap magnetic core characterized by, A single air gap magnetic core prepared by the integrated production process of any one of claims 1-9, wherein the single air gap magnetic core is composed of a single magnetic core and an air gap layer.

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