Inductor and preparation method and application thereof

Abstract

The invention provides an inductor and a preparation method and application thereof, the inductor comprises a coil which is spirally wound in a layered mode, and gaps between layers of the coil are filled with magnetic powder. According to the inductor provided by the invention, the gaps between the layers of the coil which is spirally wound in a layered manner are filled with the magnetic powder, so that the inductance value is improved, the direct-current resistance of the inductor is reduced, and the efficiency of the inductor is improved; according to the inductor, the problem that the efficiency of the inductor cannot be effectively improved due to the fact that the lacquering film is not resistant to high temperature is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of inductors and relates to an inductor, and in particular to an inductor and a preparation method and application thereof. Background Art

[0002] Currently, one-piece molded inductors are widely used in various application scenarios such as consumer electronics, industrial products, medical and automotive. Usually, one-piece molded inductors are composed of three parts: coil, powder and pad. As SMD surface mount inductors, one-piece molded inductors have the following advantages: First, the fully enclosed structure of one-piece molded inductors has good magnetic shielding effect, which can effectively reduce electromagnetic interference; second, one-piece molded inductors can ensure that the current resistance inductance value decreases smoothly; third, the application frequency of one-piece molded inductors is high, up to 5MHz; fourth, one-piece molded inductors are suitable for high reliability requirements in the automotive, military, medical and aerospace industries.

[0003] However, with the rapid development of robots and AI, the conversion efficiency of electronic components is increasingly required. For electronic devices of the same size, if the conversion efficiency is increased by 10%, the energy consumption and heat generation will decrease year-on-year. In this context, the efficiency improvement of integrated inductors is particularly important. However, the inductors in the existing technology cannot effectively improve the efficiency of the inductors because the wires are tightly wound and the enameled film is not resistant to high temperatures.

[0004] CN105989988A discloses an integrated inductor, which relates to the field of electronic technology and can dissipate the heat inside the integrated inductor, thereby ensuring that the integrated inductor will not be damaged. The integrated inductor includes a magnetic core and a coil, the coil is embedded in the magnetic core, and the integrated inductor also includes: at least one through hole penetrating the magnetic core, and the at least one through hole is used for heat dissipation of the integrated inductor.

[0005] CN205943643U discloses an integrally formed inductor. It includes a coil, a straight-cylindrical sleeve, an electrode and a powder coating layer. The coil is placed inside the straight-cylindrical sleeve, and the coil and the straight-cylindrical sleeve are tightly matched. The electrode includes a connecting part and a welding part. The connecting part of the electrode is connected to the lead pin of the coil. The straight-cylindrical sleeve, the coil and the connecting part of the electrode are buried in the center of the powder coating layer, and the welding part of the electrode is exposed on the surface of the powder coating layer. This patent protects the coil by a straight-cylindrical sleeve, and at the same time, by adjusting the material, shape and size of the straight-cylindrical sleeve, the integrally formed inductor can present a variety of choices in terms of performance parameters.

[0006] CN102737802A discloses a coil magnetic powder integrated inductor, comprising a cubic magnetic material block, an embedded coil, two opposite surfaces each with an end electrode, the end electrode is connected to one end of the coil, the magnetic material block is composed of two or more magnetic powders with different average particle sizes and insulating resin, the general formula of the magnetic powder is Fe 100-x-y-z Si x Cr y B z The manufacturing method is as follows: (i) uniformly mix magnetic powders of different particle sizes; (ii) mix magnetic powders with insulating resin to form a composite magnetic material mass; (iii) make an air-core coil; (iv) heat the forming mold and the lower punch, fill the composite magnetic material mass and the air-core coil, press and mold, keep warm until the resin is solidified and then demold; (v) polish the two end faces; (vi) vacuum sputter to form electrodes. The pressing operation can be completed with a relatively small pressure, and the pressing process causes little damage to the magnetic particles and the coil.

[0007] The inductors disclosed in the prior art all have certain defects. There is a problem that the inductor efficiency cannot be effectively improved due to the tight winding of the wire and the enamel film is not resistant to high temperature. Therefore, it is very important to develop and design a new type of inductor and its preparation method. Summary of the invention

[0008] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an inductor and a preparation method and application thereof. In the inductor provided by the present invention, the gaps between the layers of the layered spirally wound coil are filled with magnetic powder, thereby improving the inductance value, reducing the DC resistance of the inductor, and improving the efficiency of the inductor; the inductor provided by the present invention avoids the problem that the inductor efficiency cannot be effectively improved due to the enamel film being not resistant to high temperatures.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides an inductor, comprising a layered spirally wound coil, wherein gaps between layers of the coil are filled with magnetic powder.

[0011] The gaps between the layers of the layered spirally wound coil in the inductor provided by the present invention are filled with magnetic powder, thereby improving the inductance value, reducing the DC resistance of the inductor, and improving the efficiency of the inductor; the inductor provided by the present invention avoids the problem that the inductor efficiency cannot be effectively improved due to the enamel film being not resistant to high temperatures.

[0012] Preferably, the coil comprises a winding body and lead wires extending from two ends of the winding body, the coil and the magnetic powder are an integral structure, and the surface of the integral structure except for the lead wires is covered by an insulating coating layer.

[0013] Preferably, the insulating coating layer includes any one or a combination of at least two of a paint layer, an anti-rust oil layer or a resin layer. Typical but non-limiting combinations include a combination of a paint layer and an anti-rust oil layer, a combination of an anti-rust oil layer and a resin layer, or a combination of a paint layer, an anti-rust oil layer and a resin layer.

[0014] The paint layer of the present invention comprises paint, and the main component of the paint layer is epoxy resin.

[0015] The main component of the anti-rust oil layer in the present invention is water-based polymer.

[0016] The main component of the resin layer in the present invention is resin.

[0017] Preferably, the lead wire is parallel to a plane in the coil that is perpendicular to the axis, and the lead wire is used to conduct current.

[0018] Preferably, the lead wire is covered with a conductive layer, and the material of the conductive layer includes any one of tin-silver-copper alloy, nickel-tin alloy or copper-nickel-tin alloy.

[0019] In a second aspect, the present invention provides a method for preparing the inductor according to the first aspect, the method comprising:

[0020] The inductor is obtained by mixing the layered spirally wound coil and magnetic powder in a mold, and then performing compression molding and sintering in sequence.

[0021] The method for preparing an inductor provided by the present invention prepares a novel inductor in which the gaps between layers of a layered spirally wound coil are filled with magnetic powder, thereby avoiding the problem that the inductor efficiency cannot be improved by sintering.

[0022] Preferably, the method for preparing the layered spirally wound coil includes: winding the enameled wire for a set number of turns according to a set winding method, and after making adjacent turns of the coil not contact each other, bending both ends of the enameled wire to form lead wires to obtain the layered spirally wound coil.

[0023] Preferably, the set winding method is clockwise or counterclockwise spiral winding.

[0024] Preferably, the set number of turns is 3 to 30 turns, for example, it can be 3 turns, 5 turns, 7 turns, 10 turns, 12 turns, 15 turns, 17 turns, 20 turns, 23 turns, 25 turns, 27 turns or 30 turns, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the enameled wire comprises a round wire or a flat wire.

[0026] Preferably, the mixing comprises placing the layered spirally wound coil in a mold and then filling the mold with magnetic powder.

[0027] Preferably, the press forming includes cold press forming and / or hot press forming.

[0028] Preferably, the cold press molding is performed at a pressure of 700 to 1600 MPa, a temperature of -10 to 40°C, and a time of 0.1 to 1 min.

[0029] The cold press forming pressure in the present invention is 700-1600 MPa, for example, it can be 700 MPa, 800 MPa, 900 MPa, 1000 MPa, 1100 MPa, 1200 MPa, 1300 MPa, 1400 MPa, 1500 MPa or 1600 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] The temperature of the cold press forming in the present invention is -10 to 40°C, for example, it can be -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 35°C, 35°C or 40°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] The cold press forming time in the present invention is 0.1 to 1 min, for example, it can be 0.1 min, 0.2 min, 0.3 min, 0.4 min, 0.5 min, 0.6 min, 0.7 min, 0.8 min, 0.9 min or 1 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the hot pressing molding is performed at a pressure of 400 to 800 MPa, a temperature of 80 to 180° C., and a time of 1 to 2 min.

[0033] The pressure of the hot pressing molding in the present invention is 400-800 MPa, for example, it can be 400 MPa, 450 MPa, 500 MPa, 550 MPa, 600 MPa, 650 MPa, 700 MPa, 750 MPa or 800 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] The temperature of the hot pressing molding in the present invention is 80-180°C, for example, it can be 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C or 180°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] The time for hot pressing molding in the present invention is 1 to 2 minutes, for example, it can be 1 minute, 1.1 minutes, 1.2 minutes, 1.3 minutes, 1.4 minutes, 1.5 minutes, 1.6 minutes, 1.7 minutes, 1.8 minutes, 1.9 minutes or 2 minutes, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the sintering includes sequential heating and heat preservation.

[0037] Preferably, the heating rate is 10-18°C / min, and the terminal temperature is 500-720°C.

[0038] The heating rate described in the present invention is 10 to 18°C / min, for example, it can be 10°C / min, 10.5°C / min, 11°C / min, 11.5°C / min, 12°C / min, 12.5°C / min, 13°C / min, 13.5°C / min, 14°C / min, 14.5°C / min, 15°C / min, 15.5°C / min, 16°C / min, 16.5°C / min, 17°C / min, 17.5°C / min or 18°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] The terminal temperature of the heating in the present invention is 500-720°C, for example, it can be 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, 620°C, 640°C, 660°C, 680°C, 700°C or 720°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the insulation time is 20 to 180 min, for example, it can be 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min or 180 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] Preferably, after the sintering, the integrated structure formed by the coil and the magnetic powder is chamfered and ground to remove burrs at the corners.

[0042] Preferably, the chamfering and grinding further comprises coating the integrated structure with an insulating coating layer after the burrs are removed.

[0043] Preferably, the method for coating the insulating coating layer comprises placing the integrated structure after burrs are removed in a roller spraying machine for roller spraying.

[0044] Preferably, after coating with the insulating coating layer, the method further includes removing the insulating coating layer on the surface of the lead wires on both side surfaces of the integrated structure.

[0045] Preferably, the removal method includes laser paint stripping and / or grinding.

[0046] Preferably, after the removal, a conductive layer is deposited on the surfaces of the lead wires on both side surfaces of the integrated structure.

[0047] Preferably, the deposition method includes electroplating.

[0048] In a third aspect, the present invention provides an application of the inductor described in the first aspect, wherein the inductor is used in consumer electronics, medical treatment or automobiles.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The gaps between the layers of the layered spirally wound coil in the inductor provided by the present invention are filled with magnetic powder, thereby increasing the inductance value, reducing the DC resistance of the inductor, and improving the efficiency of the inductor; the inductor provided by the present invention avoids the problem that the inductor efficiency cannot be effectively improved due to the enamel film being not resistant to high temperatures;

[0051] (2) The method for preparing an inductor provided by the present invention prepares a new type of inductor in which the gaps between layers of a layered spirally wound coil are filled with magnetic powder, thereby avoiding the problem that the inductor efficiency cannot be improved by sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram of the structure of the inductor provided in Example 1.

[0053] Figure 2 This is a schematic diagram of the structure of the layered spirally wound coil provided in Example 1.

[0054] Figure 3 This is a schematic diagram of the structure of the inductor provided in Example 2.

[0055] Figure 4 This is a schematic diagram of the structure of the layered spirally wound coil provided in Example 2.

[0056] Among them, 1- enameled wire; 2- lead wire; 3- magnetic powder. DETAILED DESCRIPTION

[0057] 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.

[0058] Example 1

[0059] This embodiment provides a Figure 1 The inductor shown in FIG. Figure 2 The layered spirally wound coil shown, the gaps between the layers of the coil are filled with magnetic powder 3;

[0060] The coil comprises a winding body and lead wires 2 extending from both ends of the winding body, wherein the lead wires 2 are parallel to a plane in the coil that is perpendicular to the axis; the coil and the magnetic powder 3 are an integral structure, and the surface of the integral structure except for the lead wires 2 is covered with a paint layer, and the surface of the lead wires 2 is covered with a tin-silver-copper alloy layer, and the lead wires are used to conduct current;

[0061] The preparation method of the inductor is as follows:

[0062] (1) Winding the enameled wire 1 for a set number of turns according to a set winding method, and making sure that adjacent turns of the coil do not contact each other, then bending both ends of the enameled wire 1 to form lead wires 2, thereby obtaining a layered spirally wound coil;

[0063] (2) placing the layered spirally wound coil obtained in step (1) in a mold, filling the mold with magnetic powder 3, cold pressing the mold at 15° C. and a pressure of 1200 MPa for 0.5 min, heating the mold to 600° C. at a rate of 12° C. / min, and sintering the mold for 60 min to obtain an integrated structure of the coil and the magnetic powder 3;

[0064] (3) The integrated structure formed by the coil obtained in step (2) and the magnetic powder 3 is chamfered and ground to remove burrs at the corners, and then the integrated structure after the burrs are removed is coated with an insulating coating layer, and then the insulating coating layer on the surface of the lead wire 2 on both sides of the integrated structure is removed, and then a conductive layer is deposited on the surface of the lead wire 2 on both sides of the integrated structure to obtain the inductor.

[0065] Example 2

[0066] This embodiment provides a Figure 3 The inductor shown in FIG. Figure 4 The layered spirally wound coil shown, the gaps between the layers of the coil are filled with magnetic powder 3;

[0067] The coil comprises a winding body and lead wires 2 extending from both ends of the winding body, wherein the lead wires 2 are parallel to a plane in the coil that is perpendicular to the axis; the coil and the magnetic powder 3 are an integral structure, and the surface of the integral structure except for the lead wires 2 is covered with a paint layer, and the surface of the lead wires 2 is covered with a tin-silver-copper alloy layer, and the lead wires are used to conduct current;

[0068] The preparation method of the inductor is as follows:

[0069] (1) Winding the enameled wire 1 for a set number of turns according to a set winding method, and making sure that adjacent turns of the coil do not contact each other, then bending both ends of the enameled wire 1 to form lead wires 2, thereby obtaining a layered spirally wound coil;

[0070] (2) placing the layered spirally wound coil obtained in step (1) in a mold, filling the mold with magnetic powder 3, performing hot pressing molding at 140° C. and a pressure of 600 MPa for 1.5 min, then heating to 650° C. at a rate of 10° C. / min and sintering for 100 min to obtain an integrated structure formed by the coil and the magnetic powder 3;

[0071] (3) The integrated structure formed by the coil obtained in step (2) and the magnetic powder 3 is chamfered and ground to remove burrs at the corners, and then the integrated structure after the burrs are removed is coated with an insulating coating layer, and then the insulating coating layer on the surface of the lead wire 2 on both sides of the integrated structure is removed, and then a conductive layer is deposited on the surface of the lead wire 2 on both sides of the integrated structure to obtain the inductor.

[0072] Example 3

[0073] This embodiment provides an inductor, the inductor comprising a layered spirally wound coil, the gaps between the layers of the coil being filled with magnetic powder 3;

[0074] The coil comprises a winding body and lead wires 2 extending from both ends of the winding body, wherein the lead wires 2 are parallel to a plane in the coil that is perpendicular to the axis; the coil and the magnetic powder 3 are an integral structure, and the surface of the integral structure except for the lead wires 2 is covered with a paint layer, and the surface of the lead wires 2 is covered with a tin-silver-copper alloy layer, and the lead wires are used to conduct current;

[0075] The preparation method of the inductor is as follows:

[0076] (1) Winding the enameled wire 1 for a set number of turns according to a set winding method, and making sure that adjacent turns of the coil do not contact each other, then bending both ends of the enameled wire 1 to form lead wires 2, thereby obtaining a layered spirally wound coil;

[0077] (2) placing the layered spirally wound coil obtained in step (1) in a mold, filling the mold with magnetic powder 3, cold pressing the mold at 40° C. and a pressure of 700 MPa for 1 min, heating the mold to 720° C. at a rate of 15° C. / min, and sintering the mold for 20 min to obtain an integrated structure of the coil and the magnetic powder 3;

[0078] (3) The integrated structure formed by the coil obtained in step (2) and the magnetic powder 3 is chamfered and ground to remove burrs at the corners, and then the integrated structure after the burrs are removed is coated with an insulating coating layer, and then the insulating coating layer on the surface of the lead wire 2 on both sides of the integrated structure is removed, and then a conductive layer is deposited on the surface of the lead wire 2 on both sides of the integrated structure to obtain the inductor.

[0079] Example 4

[0080] This embodiment provides an inductor, which is the same as that of Embodiment 1 except that the pressure of cold pressing in the preparation method of the inductor is 500 MPa.

[0081] Example 5

[0082] This embodiment provides an inductor, which is the same as that of Embodiment 1 except that the pressure of cold pressing in the preparation method of the inductor is 1800 MPa.

[0083] Example 6

[0084] This embodiment provides an inductor, which is the same as that of Embodiment 2 except that the pressure of hot pressing molding in the preparation method of the inductor is 200 MPa.

[0085] Example 7

[0086] This embodiment provides an inductor, which is the same as that of Embodiment 2 except that the pressure of hot pressing molding in the preparation method of the inductor is 1000 MPa.

[0087] Example 8

[0088] This embodiment provides an inductor, which is the same as the first embodiment except that the holding temperature during the sintering process, i.e., the final temperature of the heating, is 450°C in the preparation method of the inductor.

[0089] Example 9

[0090] This embodiment provides an inductor, which is the same as the first embodiment except that the holding temperature during the sintering process, i.e., the final temperature of the heating, is 780°C in the preparation method of the inductor.

[0091] Comparative Example 1

[0092] This comparative example provides an inductor, which is a traditional one-piece molded inductor. The traditional one-piece molded inductor includes a magnetic core and a coil. The number of turns of the coil is the same as the number of turns of the layered spirally wound coil in Example 1. The coil is embedded in the magnetic core. The traditional one-piece molded inductor also includes: a through hole penetrating the magnetic core, and the through hole is used for heat dissipation of the one-piece molded inductor.

[0093] The inductors provided in the above embodiments and comparative examples were used to perform inductance value (LS@1M) test, equivalent series resistance (RS@3M) test, direct current resistance (DCR) test, inductance value at 6A (L6A) test and conversion efficiency test;

[0094] The LS@1M test method is as follows: the test instrument is a CH3302 inductance tester; the test frequency voltage is 100kHz / 1V; the test number of turns is 0.4mm25Ts, and the test results are shown in Table 1;

[0095] The RS@3M test method is: using an impedance meter method to test and obtain the equivalent series resistance, and the test results are shown in Table 1;

[0096] The DCR test method is: using a four-point electroacupuncture method to test the DC resistance of the inductor, and the test results are shown in Table 1;

[0097] The L6A test method is as follows: the test instrument is a CH3302 inductance tester; the test frequency voltage is 100kHz / 1V; the test number of turns is 0.4mm25Ts, and the test results of the inductance value of 6A are shown in Table 1;

[0098] The method for testing the conversion efficiency is as follows: by multiplying the current and voltage of the output inductor P output / the current and voltage of the input inductor P input , the conversion efficiencies at 1A, 12A, 3A, 4A, 5A, 6A, 7A and 8A are obtained as shown in Table 2.

[0099] Table 1

[0100]

[0101]

[0102] Table 2

[0103]

[0104] From Table 1 and Table 2, we can get:

[0105] (1) The inductors provided in embodiments 1 to 3 of the present invention have a large inductance value, a low series resistance and a low DC resistance, and a high conversion efficiency;

[0106] (2) By comparing Example 1 with Examples 4 and 5, it can be seen that the pressure of cold pressing in the preparation method of the inductor of the present invention will affect the performance of the inductor; when the pressure of cold pressing is too low, the LS@1M of the inductor will decrease, the RS@3M will increase, the DCR will increase, the L6A will decrease, and the conversion efficiency will decrease. This is because using appropriate pressure in cold pressing helps to increase the density of magnetic powder. If the pressure is too low, it may cause insufficient density of magnetic powder, affecting the electrical performance of the inductor; when the pressure of cold pressing is too high, the LS@1M of the inductor will decrease, the RS@3M will increase, the DCR will increase, the L6A will decrease, and the conversion efficiency will decrease. This is because excessive pressure may cause the inductor coil to deform or be damaged, affecting the electrical characteristics and mechanical strength of the coil. Excessive pressure in cold pressing may also cause cracks inside the inductor. These cracks may cause the inductor to fail in subsequent use.

[0107] (2) By comparing Example 2 with Examples 6 and 7, it can be seen that the pressure of cold pressing in the preparation method of the inductor of the present invention will affect the performance of the inductor; when the pressure of hot pressing is too low, the LS@1M of the inductor will be reduced, the RS@3M will be increased, the DCR will be increased, the L6A will be reduced, and the conversion efficiency will be reduced. This is because the use of appropriate pressure in hot pressing helps to increase the density of magnetic powder. If the pressure is too low, it may lead to insufficient density of magnetic powder, affecting the electrical performance of the inductor; when the pressure of hot pressing is too high, the LS@1M of the inductor will be reduced, the RS@3M will be increased, the DCR will be increased, the L6A will be reduced, and the conversion efficiency will be reduced. This is because excessive pressure may cause the inductor coil to deform or be damaged, affecting the electrical characteristics and mechanical strength of the coil. Excessive pressure in hot pressing may also cause cracks inside the inductor. These cracks may cause the inductor to fail in subsequent use.

[0108] (3) By comparing Example 1 with Examples 8 and 9, it can be seen that the holding temperature during the sintering process in the preparation method of the inductor described in the present invention, that is, the terminal temperature of the heating, will affect the performance of the inductor; when the holding temperature is too low, the LS@1M of the inductor will become smaller, the RS@3M will become larger, the DCR will become larger, the L6A will become smaller, and the conversion efficiency will become smaller. This is because the low holding temperature will lead to insufficient bonding between the magnetic powder particles in the gaps between the layers of the coil, thereby affecting the overall density and mechanical strength of the inductor, thereby affecting the performance of the inductor. In addition, insufficient sintering temperature will affect the microstructure and grain growth of the magnetic powder, and it is impossible to achieve ideal magnetic properties; when the holding temperature is too high, the LS@1M of the inductor will become smaller, the RS@3M will become larger, the DCR will become larger, the L6A will become smaller, and the conversion efficiency will become smaller. This is because the high holding temperature will cause excessive sintering of the magnetic powder, causing abnormal grain growth, thereby reducing the magnetic properties of the material;

[0109] (4) By comparing Example 1 with Comparative Example 1, it can be seen that the gaps between the layers of the layered spirally wound coil in the inductor provided by the present invention are filled with magnetic powder 3, thereby improving the inductance value, reducing the DC resistance of the inductor, and improving the efficiency of the inductor; the inductor provided by the present invention avoids the problem that the inductor efficiency cannot be effectively improved due to the enamel film being not resistant to high temperatures.

[0110] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. An inductor, It is characterized in that The inductor includes a layered spirally wound coil, and gaps between layers of the coil are filled with magnetic powder.

2. The inductor according to claim 1, It is characterized in that The coil comprises a winding body and lead wires extending from two ends of the winding body. The coil and the magnetic powder are an integral structure, and the surface of the integral structure except the lead wires is covered by an insulating coating layer.

3. The inductor according to claim 2, It is characterized in that The lead wire is parallel to a plane in the coil that is perpendicular to the axis, and the lead wire is used to conduct current.

4. A method for preparing the inductor according to any one of claims 1 to 3, It is characterized in that The preparation method comprises: The inductor is obtained by mixing the layered spirally wound coil and magnetic powder in a mold, and then performing compression molding and sintering in sequence.

5. The preparation method according to claim 4, It is characterized in that The method for preparing the layered spirally wound coil includes: winding the enameled wire for a set number of turns according to a set winding method, and after making adjacent turns of the coil not contact each other, bending both ends of the enameled wire to form lead wires to obtain the layered spirally wound coil.

6. The preparation method according to claim 4 or 5, It is characterized in that The mixing includes placing the layered spirally wound coil in a mold and then filling the mold with magnetic powder.

7. The preparation method according to any one of claims 4 to 6, It is characterized in that The press forming includes cold press forming and / or hot press forming; Preferably, the cold press molding is performed at a pressure of 700 to 1600 MPa, a temperature of -10 to 40°C, and a time of 0.1 to 1 min; Preferably, the hot pressing molding is performed at a pressure of 400 to 800 MPa, a temperature of 80 to 180° C., and a time of 1 to 2 min.

8. The preparation method according to any one of claims 4 to 7, It is characterized in that The sintering includes sequentially heating and heat preservation; Preferably, the heating rate is 10-18°C / min, and the terminal temperature is 500-720°C; Preferably, the insulation time is 20 to 180 minutes.

9. The preparation method according to any one of claims 4 to 8, It is characterized in that After the sintering, the integrated structure formed by the coil and the magnetic powder is chamfered and ground to remove burrs at the corners; Preferably, after the chamfering and grinding, the method further comprises coating the integrated structure after the burrs are removed with an insulating coating layer; Preferably, after coating with the insulating coating layer, the method further includes removing the insulating coating layer on the lead wire surface on both side surfaces of the integrated structure; Preferably, after the removing, the method further comprises depositing a conductive layer on the surfaces of the lead wires on both side surfaces of the integrated structure.

10. An application of the inductor according to any one of claims 1 to 3, It is characterized in that The inductors are used in consumer electronics, medical or automotive applications.

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