CN114360861A - Surface-mounted power inductor and preparation method thereof - Google Patents
Surface-mounted power inductor and preparation method thereof Download PDFInfo
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- CN114360861A CN114360861A CN202111664372.0A CN202111664372A CN114360861A CN 114360861 A CN114360861 A CN 114360861A CN 202111664372 A CN202111664372 A CN 202111664372A CN 114360861 A CN114360861 A CN 114360861A
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Abstract
The invention discloses a surface-mounted power inductor which comprises a soft magnetic alloy center pillar, a coil, a magnetic powder part and a terminal electrode, wherein the soft magnetic alloy center pillar is arranged on the center pillar; the coil is wound on the soft magnetic alloy center post, and the magnetic powder part is coated outside the assembly of the soft magnetic alloy center post and the coil; two ends of the coil are led out of the magnetic powder part and are respectively connected with the corresponding end electrodes. The center post of the chip type power inductor is prepared by the amorphous magnetically soft alloy block and the nanocrystalline magnetically soft alloy block, has higher magnetic conductivity than the center post prepared by the magnetically soft alloy powder in the prior art, can greatly improve the inductance value of the inductor under the condition that the size of the inductor is not changed or even reduced, or obviously reduces the number of turns of a coil and the size of the center post under the condition that the inductance value is not changed, realizes the reduction of the size of the inductor and the improvement of comprehensive performance, and is favorable for the development of the chip type power inductor towards the directions of miniaturization, lightness and thinness, large current, low electromagnetic interference and the like.
Description
Technical Field
The invention relates to the technical field of inductance elements, in particular to a patch type power inductor and a preparation method thereof.
Background
The patch type power inductor is used as a basic electronic element and is widely applied to various electronic devices or electronic control circuits. In the current development of various electronic devices towards miniaturization, light weight and multiple functions, the number of applied patch type power inductors is more and more, but new requirements for miniaturization, low installation thickness, large inductance and the like are also provided for the patch type power inductors.
The current patch type power inductor mainly comprises a soft magnetic material, a coil, a terminal electrode and the like, wherein the soft magnetic material penetrates through the coil and is also coated outside the coil to play a role in shielding an electromagnetic field. The soft magnetic material used by the surface mount type power inductor is generally made of soft magnetic alloy powder through the processes of bonding, mould pressing, curing and the like, and the magnetic conductivity is low, so that the coil of the inductor has more turns and larger size, and the requirements of miniaturization and large inductance of the current inductor are not facilitated.
As disclosed in patent specification publication No. CN102856037B, a molded power inductor comprises a preformed magnetic core, a coil disposed on the preformed magnetic core, and a magnetic molding layer molded over the magnetic core and the coil, with electrodes connected to the coil exposed. The magnetic core plastic package layer in the patent is composed of soft magnetic powder particles, an organic adhesive, a lubricant and a curing agent, and the prefabricated magnetic core is also manufactured through a mould pressing or injection molding process of the soft magnetic powder. Or as disclosed in patent specification No. CN104616878B, a method for manufacturing a micro molded inductance component comprises prefabricating a magnetic core and a coil, forming the magnetic core and the coil into an assembly, molding a powder and the assembly to form a compact, metallizing an electrode, finishing a leg, and forming an end electrode. The prefabricated magnetic core in the patent adopts ferrite or metal soft magnetic materials as molding powder, and the powder used in the step of molding the powder is also prepared from insulated soft magnetic powder, organic adhesive, hardening agent and lubricant. Both of the two technical solutions have the problems of low magnetic permeability and unfavorable inductance miniaturization mentioned above.
The coil size of the prior small-size and high-inductance patch type power inductor is very close to the size of an inductor finished product, so that the problems of exposed coil, magnetic leakage and the like are easily caused, hidden dangers are generated on the reliability and safety of subsequent use of the inductor, and the manufacturing difficulty and cost of the small-size inductor are greatly increased.
Therefore, the structure and the process of the current patch type power inductor are not satisfactory, and further improvement is needed.
Disclosure of Invention
The invention aims to provide a novel chip type power inductor design, which solves the problems that the coil size is large, the size of an inductor finished product is difficult to reduce, the inductance is difficult to increase and the like in the conventional chip type power inductor design.
A patch type power inductor comprises a soft magnetic alloy center pillar, a coil, a magnetic powder part and a terminal electrode; the coil is wound on the soft magnetic alloy center post, and the magnetic powder part is coated outside the assembly of the soft magnetic alloy center post and the coil; two ends of the coil are led out of the magnetic powder part and are respectively connected with the corresponding end electrodes.
Preferably, the outer surface of the magnetic powder part is coated with an insulating coating layer.
More preferably, the insulating coating material is at least one of epoxy resin, polyurethane, silicone resin, amino resin, polyimide resin, phenolic resin, cyanate ester, and acrylic resin.
Preferably, the cross section of the soft magnetic alloy center pillar is circular, oval or racetrack shaped, and the material of the soft magnetic alloy center pillar is one of amorphous soft magnetic alloy block material and nanocrystalline soft magnetic alloy block material.
Preferably, the coil is a flat enameled copper wire or a self-adhesive round enameled wire.
Preferably, the winding shape of the coil is circular, oval or racetrack, and the coil is fixed with the soft magnetic alloy center column in a clearance fit mode.
Another object of the present invention is to provide a method for manufacturing a chip power inductor, comprising the following steps:
s1, prefabricating a soft magnetic alloy center column: pouring the soft magnetic alloy liquid into a center pillar die, rapidly cooling to obtain a soft magnetic alloy center pillar blank, demolding the blank, processing to obtain a center pillar blank with a designed size, and then carrying out heat treatment on the blank to obtain a soft magnetic alloy center pillar;
s2, prefabricating a coil: winding the enameled wire into a coil according to the design size and shape;
s3, preparing a cup magnet: filling the soft magnetic alloy composite powder into a cup-shaped mold and pressing and molding to obtain a cup-shaped magnet with a magnetic core cavity, wherein the cup-shaped magnet is not demolded and enters the next procedure along with the mold;
s4, prefabricating a flat plate magnet: filling the soft magnetic alloy composite powder into a flat plate die, pressing and molding, and demolding to obtain a flat plate magnet;
s5, hot press forming: combining the soft magnetic alloy central column, the coil, the cup-shaped magnet and the flat magnet, performing hot press molding, demolding, baking and curing to obtain an inductance semi-finished product;
s6, spraying: spraying an insulating protective material on the surface of the semi-finished inductor product prepared in the step S5, and baking to cure the insulating protective material on the surface;
s7, electrode preparation: and (5) stripping the insulating protection material at the coil end of the semi-finished inductor product prepared in the step (S6) and the enamel of the enameled wire, and electroplating an electrode at the enamel stripping position to obtain the patch type power inductor.
Preferably, the step S5 is specifically: inserting the soft magnetic alloy center posts obtained in the step S1 into the coil obtained in the step S2, then placing the assembly of the coil and the soft magnetic alloy center posts into the magnetic core cavity of the cup-shaped magnet obtained in the step S3, finally placing the flat magnet obtained in the step S4 on the top of the cup-shaped magnet for hot press molding, demolding, baking and curing to obtain the semi-finished inductor.
Preferably, the soft magnetic alloy composite powder material in step S3 and step S4 is a composite material of soft magnetic alloy powder, binder and lubricant.
Preferably, the soft magnetic alloy powder is at least one selected from amorphous soft magnetic alloy powder, nanocrystalline soft magnetic alloy powder, iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder, iron-silicon-nickel alloy powder, iron-silicon-aluminum-nickel alloy powder, iron-nickel-aluminum alloy powder and carbonyl iron powder.
Preferably, the binder is at least one of epoxy resin, polyurethane, silicone resin, amino resin, polyimide, phenolic resin, cyanate ester and acrylic resin; the lubricant is at least one of zinc stearate, magnesium stearate, aluminum stearate, calcium stearate, graphite powder and graphene.
Preferably, the flat-plate magnet is provided with an electrode slot for leading out the coil end.
The invention has the beneficial effects that:
(1) compared with the center column prepared by bonding soft magnetic alloy powder in the prior art, the center column of the surface mount type power inductor has higher magnetic conductivity, can realize the reduction of the size of the center column and the number of turns of a coil, and greatly improves the inductance, namely: the inductance value of the inductor can be greatly increased under the condition that the size of the inductor is not changed or even reduced, or the size of the finished inductor can be obviously reduced under the condition that the inductance value is kept unchanged.
(2) The inductance value is unchanged or increased, the number of turns of the coil is reduced, the direct current resistance (Rdc) of the inductor is reduced, the magnetic powder part has a better coating effect on the coil, the problems of exposure, magnetic leakage and the like of the coil are effectively avoided, and the comprehensive performance of the inductor is greatly improved.
Drawings
Fig. 1 is a perspective view of the overall structure of the patch type power inductor of the present invention;
FIG. 2 is a schematic view of a center pillar of the soft magnetic alloy of the present invention;
FIG. 3 is a schematic diagram of the coil structure of the present invention;
FIG. 4 is a schematic structural view of a coil and soft magnetic alloy king post assembly of the present invention;
FIG. 5 is a schematic view of the structure of a cup-shaped magnet according to the present invention;
FIG. 6 is a schematic view showing the structure of the coil, soft magnetic alloy center post, and cup-shaped magnet assembly of the present invention;
FIG. 7 is a schematic view of the structure of a flat plate magnet according to the present invention;
fig. 8 is a perspective schematic view of a chip type power inductor semi-finished product according to the present invention;
fig. 9 is a schematic diagram of a winding core structure of the chip-on-board power inductor of comparative example 1;
fig. 10 is a flow chart of a manufacturing process of the patch type power inductor of the present invention.
The figures are numbered: 1. a soft magnetic alloy center post; 2. a coil; 21. a coil end; 3. a magnetic powder portion; 4. A terminal electrode; 5. an insulating coating layer; 6. a cup-shaped magnet; 61. a magnetic core cavity; 7. a flat plate magnet; 71. An electrode tank; 8. a T-shaped magnet; 81. t-shaped magnet center post.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, a chip power inductor includes a soft magnetic alloy center pillar 1, a coil 2, a magnetic powder portion 3, a terminal electrode 4, and an insulating coating layer 5.
Wherein, the coil 2 is wound on the soft magnetic alloy center post 1, as shown in fig. 2-4, the coil 2 and the soft magnetic alloy center post 1 are fixed by clearance fit; the magnetic powder part 3 is completely coated outside the assembly of the soft magnetic alloy center post 1 and the coil 2 to form a cuboid shape, and the insulating coating layer 5 is coated on the outer surface of the magnetic powder part 3; the number of the end electrodes 4 is two, two ends 21 of the coil 2 are led out of the magnetic powder part 3 and are respectively connected with the two end electrodes 4, and the end electrodes 4 are embedded on the surface of the magnetic powder part 3 and are exposed out of the insulating coating layer 5.
In this embodiment, the two terminal electrodes 4 are disposed on the bottom surface of the inductor along the width direction of the inductor and located at two ends of the inductor along the length direction of the inductor.
In this embodiment, the magnetic powder portion 3 is formed by die pressing a composite material of soft magnetic alloy powder, a binder and a lubricant; the soft magnetic alloy powder is at least one selected from amorphous soft magnetic alloy powder, nanocrystalline soft magnetic alloy powder, iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder, iron-silicon-nickel alloy powder, iron-silicon-aluminum-nickel alloy powder, iron-nickel-aluminum alloy powder and carbonyl iron powder.
In this embodiment, the soft magnetic alloy center pillar 1 can be made of one of an amorphous soft magnetic alloy block and a nanocrystalline soft magnetic alloy block; particularly Fe-Si-B-P-Cu amorphous soft magnetic alloy is selected. The cross section of the soft magnetic alloy center post 1 is circular, oval or racetrack shaped; in particular a racetrack shape.
In this embodiment, the insulating coating layer 5 is made of at least one of epoxy resin, polyurethane, silicone resin, amino resin, polyimide resin, phenolic resin, cyanate ester, and acrylic resin; epoxy resin is particularly selected.
In the embodiment, the coil 2 is a flat enameled copper wire or a self-adhesive round enameled wire; a flat enameled copper wire is selected, and the winding shape of the coil 2 is a track shape consistent with the cross section shape of the soft magnetic alloy center pillar 1.
As shown in fig. 10, a flow chart of a manufacturing process of a chip power inductor is used for manufacturing the chip power inductor, and specifically includes the following steps:
s1, prefabricating a soft magnetic alloy center column: pouring the soft magnetic alloy liquid into a center pillar die, rapidly cooling to obtain a soft magnetic alloy center pillar blank, demolding the blank, processing to obtain a center pillar blank with a designed size, and then carrying out heat treatment on the blank to obtain a soft magnetic alloy center pillar;
s2, prefabricating a coil: winding the enameled wire into a coil according to the designed size and shape;
s3, preparing a cup magnet: filling the soft magnetic alloy composite powder into a cup-shaped mold and pressing and molding to obtain a cup-shaped magnet with a magnetic core cavity, wherein the cup-shaped magnet is not demolded and enters the next procedure along with the mold;
s4, prefabricating a flat plate magnet: filling the soft magnetic alloy composite powder into a flat plate die, pressing and molding, and demolding to obtain a flat plate magnet;
s5, hot press forming: combining the soft magnetic alloy central column, the coil, the cup-shaped magnet and the flat magnet, performing hot press molding, demolding, baking and curing to obtain an inductance semi-finished product;
s6, spraying: spraying an insulating protective material on the surface of the semi-finished inductor product prepared in the step S5, and baking to cure the insulating protective material on the surface;
s7, electrode preparation: and (5) stripping the insulating protection material at the coil end of the semi-finished inductor product prepared in the step (S6) and the enamel of the enameled wire, and electroplating an electrode at the enamel stripping position to obtain the patch type power inductor.
Example 1
In this embodiment, the soft magnetic alloy center pillar material is a Fe-Si-B-P-Cu amorphous soft magnetic alloy bulk material, the soft magnetic alloy composite powder material is a composite powder obtained by mixing Fe-Ni soft magnetic alloy powder and iron powder, the binder is epoxy resin, and the lubricant is zinc stearate, and the composite powder is mixed with the binder, the lubricant and acetone and then screened to obtain the target soft magnetic composite powder material, wherein the preparation method of the surface mount type power inductor in this embodiment specifically includes the following steps:
s1, prefabricating a soft magnetic alloy center column: weighing a certain amount of Fe-Si-B-P-Cu master alloy according to the mass ratio, placing the Fe-Si-B-P-Cu master alloy in a vacuum smelting furnace, completely smelting, pouring soft magnetic alloy liquid into a center pillar die, quickly cooling to obtain a soft magnetic alloy center pillar blank, demoulding the blank, processing to obtain a center pillar blank with the size of 1.2 x 0.8 x 0.7mm, and then placing the blank in a vacuum heat treatment furnace for heat treatment at 380 ℃ for 120min to obtain a soft magnetic alloy center pillar 1 (shown in figure 2);
s2, prefabricating a coil: selecting a flat enameled copper wire with the specification of 0.065 multiplied by 0.33mm, winding 7.5 turns of enameled wire on a winding jig through an automatic winding machine, horizontally bending two end heads 21 of the enameled wire, and taking out the enameled wire from the winding jig to obtain a coil 2 (shown in figure 3) with a specific size and shape;
s3, preparing a cup magnet: the screened soft magnetic alloy composite powder is loaded into a cup-shaped die with a preset structure and size, a high-precision servo forming press is started to perform punch forming at normal temperature to obtain a cup-shaped magnet 6 (shown in figure 5) with a magnetic core cavity 61, the cup-shaped magnet 1 is placed in a cold press forming die to be not separated, and the cup-shaped magnet enters the next working procedure along with the die;
wherein the cold pressing pressure used when pressing the cup-shaped magnet 1 is 3t/cm2The dwell time was 1 s.
S4, prefabricating a flat plate magnet: the screened soft magnetic alloy composite powder is put into a flat plate cold press molding die with a preset structure and size, a high-precision servo molding press is started to perform punch molding at normal temperature, and a flat plate magnet 7 (shown in figure 7) with two electrode grooves 71 is obtained, wherein the electrode grooves 71 are used for leading out the end heads 21 of the coils 2;
wherein the cold pressing pressure adopted when pressing the flat magnet 7 is 3t/cm2The dwell time was 1 s.
S5, hot press forming: placing the cup-shaped magnet 6 prepared in the step S3 with the opening facing upwards in the mold cavity along with the mold, heating the whole mold to 180 ℃ and preserving heat; the soft magnetic alloy center post 1 prepared in step S1 is inserted inside the coil 2 of step S2 (as shown in fig. 4), the assembly of the coil 2 and the soft magnetic alloy center post 1 is placed inside the core cavity 61 of the cup-shaped magnet 6 (as shown in fig. 6), and then the flat plate magnet 7 is placed on top of the cup-shaped magnet 6; placing the die on a machine table of a hot-press forming machine, starting the forming press to perform hot-press forming, demolding to obtain an inductor blank, and baking the inductor blank to obtain a cured inductor semi-finished product (as shown in fig. 8);
wherein the hot pressing pressure adopted in the hot pressing is 3t/cm2The pressure maintaining time is 150s, and the heat preservation temperature is 180 ℃. Baking and curing the inductor blank, and specifically, putting the inductor blank into an ovenHeating and raising the temperature to enable the resin in the inductance blank body to perform a curing reaction to obtain the inductance blank body. The resin adopted here is epoxy resin, and only has small volume shrinkage during curing, so that the inductance blank body is not deformed after curing and molding. Specifically, the baking curing temperature is 180 ℃, baking equipment with a temperature rise and fall stepped curve can be selected, heat preservation is carried out for 3 hours, and finally a semi-finished inductor product is obtained, wherein the size of the semi-finished inductor product is 2.0 multiplied by 1.6 multiplied by 1.0 mm.
S6, spraying: and (4) adopting constant-temperature heating spraying equipment, coating a layer of epoxy resin protective material, namely the insulating coating layer 5, on the surface of the inductor semi-finished product prepared in the step S5, and then baking the sprayed inductor semi-finished product to cure the epoxy resin on the surface of the inductor semi-finished product. Wherein, the baking conditions are as follows: baking for 2h at 150 ℃ to cure the resin on the surface of the semi-finished inductor.
S7, electrode preparation: and (2) stripping the epoxy resin protective material and the copper wire enamel on the surface of the copper electrode at the end 21 of the semi-finished inductor prepared in the step (S6) by using laser paint stripping equipment to expose the copper electrode at the bottom, and electroplating a copper layer, a nickel layer and a tin layer at the paint stripping position to realize leading-out of the end electrode 4 to obtain the patch type power inductor (as shown in figure 1).
And testing the prepared patch type power inductor sample, wherein the average inductance Ls of the sample under the condition of 1V/1MHz is 1.173 muH, the average saturation current Isat is 4.81A, and the average direct current resistance Rdc is 31.5m omega.
Comparative example 1
The comparative example adopts the structural design and the preparation technology of the existing patch type power inductor, namely, the center column of the inductor is prepared by adopting soft magnetic alloy composite powder through mould pressing and curing processes, and the finished product of the inductor is prepared by adopting the steps of prefabricating a T-shaped magnet, winding on the T-shaped magnet, hot press molding, spraying and manufacturing an electrode which are commonly used in the industry. The soft magnetic alloy composite powder material, the enameled wire, the binder, the lubricant and the external insulation coating material which are the same as those in the embodiment 1 are selected, the size and the shape of the center pillar in the inductor, the number of turns and the shape of the coil, the electrode structure and the size, the size of the inductor finished product and other parameters are the same as those in the embodiment 1, but the amorphous soft magnetic alloy block material or the nanocrystalline soft magnetic alloy block material is not used for preparing the center pillar, but the soft magnetic alloy composite powder material is used for preparing the center pillar of the inductor. The preparation method of the inductor in the comparative example specifically comprises the following steps:
s1, prefabricating a T-shaped magnet: the screened soft magnetic alloy composite powder is filled into a T-shaped die with a preset structure and size, a high-precision servo forming press is started to perform compression forming at normal temperature, and then demoulding is performed to obtain a first T-shaped magnet; and (3) putting the first T-shaped magnet into an oven for baking to obtain a T-shaped magnet 8 with certain strength.
Wherein the cold pressing pressure used in pressing the magnet is 3t/cm2The pressure maintaining time is 1s, the baking temperature is 160 ℃, and the baking time is 30 min.
S2, winding of the coil: an enameled wire is wound on the magnet center post 81 on the T-shaped magnet 8 by using an automatic winding machine, 7.5 turns are wound, and pins at two ends are bent and then attached to the flat bottom surface of the T-shaped magnet 8, so that a winding magnetic core is obtained (as shown in fig. 9).
S3, hot press forming: and placing the winding magnetic core in a hot-pressing forming die, placing the T-shaped magnet in a 'seam' shape, placing the soft magnetic alloy composite powder material on the upper part of the winding magnetic core for hot-pressing forming, and baking and curing after demoulding to obtain a semi-finished inductor product.
Wherein the hot pressing pressure adopted in the hot pressing is 3t/cm2The pressure maintaining time is 150s, and the heat preservation temperature is 180 ℃. And baking and curing the inductor blank, specifically, putting the inductor blank into an oven for heating and raising the temperature, so that the resin in the inductor blank is subjected to a curing reaction to obtain the inductor blank. The resin adopted here is epoxy resin, and only has small volume shrinkage during curing, so that the inductance blank body is not deformed after curing and molding. Specifically, the baking curing temperature is 180 ℃, baking equipment with a temperature rise and fall stepped curve can be selected, heat preservation is carried out for 3 hours, and finally a semi-finished inductor product is obtained, wherein the size of the semi-finished inductor product is 2.0 multiplied by 1.6 multiplied by 1.0 mm.
S4, spraying: the spraying process was as in step S6 of example 1.
S5, electrode preparation: the electrode was fabricated as in step S7 of example 1.
The main properties of the prepared inductor samples were tested using the same performance testing equipment and conditions as in example 1, and the measured performance parameters are shown in table 1.
Comparative example 2
The comparison example adopts another structure design and preparation technology of the existing patch type power inductor, and the inductor finished product preparation adopts the steps of 'prefabricating a coil, filling powder, hot press molding, spraying and manufacturing an electrode' which are commonly used in the industry. The soft magnetic alloy composite powder material, the enameled wire, the binder, the lubricant and the external insulating coating material which are the same as those in the embodiment 1 are selected, the winding turns and the shape of the coil, the electrode structure and the size, the size of the inductor finished product and other parameters are the same as those in the embodiment 1, but the amorphous soft magnetic alloy block material or the nanocrystalline soft magnetic alloy block material is not used for preparing the center column, the soft magnetic alloy composite powder material and the coil are combined and pressed to prepare the patch type power inductor, and the center column of the inductor is a part formed by die pressing and curing the soft magnetic alloy composite powder material in the coil. The preparation method of the patch type power inductor in the comparative example specifically comprises the following steps:
s1, prefabricating a coil: a flat enameled copper wire with the specification of 0.065 multiplied by 0.33mm is selected to be wound on a winding jig by an automatic winding machine for 7.5 turns of enameled wire, two end heads 21 of the enameled wire are bent horizontally, and the enameled wire is taken out of the winding jig to obtain a coil 2 (shown in figure 3) with a specific size and a specific shape.
S2, hot press forming: and (3) placing the prefabricated coil 2 in the step (S1) in a die cavity of a hot-press forming die, filling the soft magnetic alloy composite powder into the die cavity, then placing the die on a machine table of a hot-press forming machine, starting the forming press to carry out hot-press forming, and baking and curing after demoulding to obtain a semi-finished inductor product, wherein the size of the semi-finished inductor product is 2.0 multiplied by 1.6 multiplied by 1.0 mm.
Wherein the hot pressing pressure adopted in the hot pressing is 3t/cm2The pressure maintaining time is 150s, and the heat preservation temperature is 180 ℃. And baking and curing the inductor blank, specifically, putting the inductor blank into an oven for heating and raising the temperature, so that the resin in the inductor blank is subjected to a curing reaction to obtain the inductor blank. The resin used here is an epoxy resinAnd only small volume shrinkage is realized during curing, so that the inductance blank body is not deformed after curing and molding. Specifically, the baking curing temperature is 180 ℃, baking equipment with a temperature rise and fall stepped curve can be selected, heat preservation is carried out for 3 hours, and finally the semi-finished inductor product is obtained.
S3, spraying: the spraying process was as in step S6 of example 1.
S4, electrode preparation: the electrode was fabricated as in step S7 of example 1.
The main properties of the prepared inductor samples were tested using the same performance testing equipment and conditions as in example 1, and the measured performance parameters are shown in table 1.
Table 1 performance parameters of the chip-type power inductors manufactured in example 1 and comparative examples 1 to 2
Example 2
In this embodiment, the size specification of the patch type power inductor is the same as that in embodiment 1, only the number of turns of the coil is reduced to 5.5 turns, the soft magnetic alloy composite powder is composite powder formed by mixing Fe-Si-B-Nb-Cu nanocrystalline soft magnetic alloy powder and iron powder, and the rest of the structural parameters, raw materials, preparation technology and process parameters of the inductor are the same as those in embodiment 1, which is described in detail in embodiment 1. After a patch type power inductance sample is obtained, an impedance analyzer is utilized to measure that the average inductance Ls of the sample under the condition of 1V/1MHz is 1.032 muH, the average saturation current Isat is 4.8A, and the average direct current resistance Rdc is 28.2m omega.
Comparative example 3
The comparative example adopts the structural design and the preparation technology of the existing patch type power inductor, namely, the center column of the inductor is prepared by adopting soft magnetic alloy composite powder through mould pressing and curing processes, and the finished product of the inductor is prepared by adopting the steps of prefabricating a T-shaped magnet, winding on the T-shaped magnet, hot press molding, spraying and manufacturing an electrode which are commonly used in the industry.
The size specification of the patch type power inductor in the comparative example is the same as that of the example 2, the soft magnetic alloy composite powder material which is the same as that in the example 2, namely the composite powder formed by mixing the Fe-Si-B-Nb-Cu nanocrystalline soft magnetic alloy powder and the iron powder is selected, the number of turns of the coil is 6.5 turns, the amorphous soft magnetic alloy block or the nanocrystalline soft magnetic alloy block is not used for preparing the center column, and the soft magnetic alloy composite powder material is used for preparing the center column of the inductor. The rest of the inductance structure parameters, raw materials and the like are the same as those of the embodiment 2, and the inductance manufacturing method, steps, process parameters and the like are the same as those of the comparative example 1, which is detailed in the comparative example 1. The prepared inductance samples were subjected to performance tests using the same performance test equipment and conditions as in example 2, and the obtained performance parameters are shown in table 2.
Comparative example 4
The comparison example adopts another structure design and preparation technology of the existing patch type power inductor, and the inductor finished product preparation adopts the steps of 'prefabricating a coil, filling powder, hot press molding, spraying and manufacturing an electrode' which are commonly used in the industry.
The size specification of the chip type power inductor in the comparative example is the same as that of the example 2, the soft magnetic alloy composite powder material which is the same as that in the example 2, namely the composite powder formed by mixing Fe-Si-B-Nb-Cu nanocrystalline soft magnetic alloy powder and iron powder, is selected, the number of turns of the coil is 7.5 turns, an amorphous soft magnetic alloy block or a nanocrystalline soft magnetic alloy block is not used for preparing a center column, the chip type power inductor is prepared by combining and pressing the soft magnetic alloy composite powder material and the coil, and the center column of the inductor is a part formed by pressing and curing the soft magnetic alloy composite powder material in the coil. The rest of the inductor structure parameters, raw materials and the like are the same as those of the embodiment 2, and the inductor manufacturing method, steps, process parameters and the like are the same as those of the comparative example 2, which is detailed in the comparative example 2. The prepared inductance samples were subjected to performance tests using the same performance test equipment and conditions as in example 2, and the obtained performance parameters are shown in table 2.
Table 2 performance parameters of the chip-type power inductors manufactured in example 2 and comparative examples 3 to 4
Table 1 and table 2 include differences in the manufacturing process of the chip power inductors in examples 1 to 2 and comparative examples 1 to 4, and properties of the finally generated chip power inductors, such as direct current resistance Rdc, saturation current Isat, and inductance Ls.
By comparing the embodiment 1 with the comparative examples 1 and 2, the center pillar of the surface mount type power inductor prepared by the amorphous soft magnetic alloy block material has higher magnetic conductivity, is very beneficial to improving the inductance and the saturation current of the inductor, and reduces the direct current resistance (Rdc) of the inductor.
It can be seen from the comparison between the embodiment 2 and the comparative examples 3 and 4 that the chip power inductor design of the present invention can achieve the significant reduction of the number of turns of the coil and the substantial reduction of the direct current resistance of the inductor while the inductance remains unchanged or increases, and because of the reduction of the number of turns of the coil, the magnetic powder portion of the inductor occupies a larger volume under the condition of the same size specification, the coil is better coated, the problems of the exposure and the magnetic leakage of the coil are effectively avoided, and the comprehensive performance of the inductor is greatly improved.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.
Claims (10)
1. A patch type power inductor is characterized by comprising a soft magnetic alloy center pillar, a coil, a magnetic powder part and a terminal electrode; the coil is wound on the soft magnetic alloy center post, and the magnetic powder part is coated outside the assembly of the soft magnetic alloy center post and the coil; two ends of the coil are led out of the magnetic powder part and are respectively connected with the corresponding end electrodes.
2. The patch type power inductor according to claim 1, wherein an outer surface of the magnetic powder portion is coated with an insulating coating layer, and the insulating coating layer is made of at least one of epoxy resin, polyurethane, silicone resin, amino resin, polyimide resin, phenolic resin, cyanate ester, and acrylic resin.
3. The surface mount type power inductor according to claim 1, wherein the cross section of the soft magnetic alloy center pillar is circular, oval or racetrack shaped, and the material of the soft magnetic alloy center pillar is one of an amorphous soft magnetic alloy block and a nanocrystalline soft magnetic alloy block.
4. The patch type power inductor according to claim 1, wherein the coil is a flat enameled copper wire or a self-adhesive round enameled wire, and the coil is wound in a round, oval or racetrack shape and fixed to the soft magnetic alloy center post in a clearance fit manner.
5. A preparation method of a patch type power inductor is characterized by comprising the following steps:
s1, prefabricating a soft magnetic alloy center column: pouring the soft magnetic alloy liquid into a center pillar die, rapidly cooling to obtain a soft magnetic alloy center pillar blank, demolding the blank, processing to obtain a center pillar blank with a designed size, and then carrying out heat treatment on the blank to obtain a soft magnetic alloy center pillar;
s2, prefabricating a coil: winding the enameled wire into a coil according to the designed size and shape;
s3, preparing a cup magnet: filling the soft magnetic alloy composite powder into a cup-shaped mold and pressing and molding to obtain a cup-shaped magnet with a magnetic core cavity, wherein the cup-shaped magnet is not demolded and enters the next procedure along with the mold;
s4, prefabricating a flat plate magnet: filling the soft magnetic alloy composite powder into a flat plate die, pressing and molding, and demolding to obtain a flat plate magnet;
s5, hot press forming: combining the soft magnetic alloy central column, the coil, the cup-shaped magnet and the flat magnet, performing hot press molding, demolding, baking and curing to obtain an inductance semi-finished product;
s6, spraying: spraying an insulating protective material on the surface of the semi-finished inductor product prepared in the step S5, and baking to cure the insulating protective material on the surface;
s7, electrode preparation: and (5) stripping the insulating protection material at the coil end of the semi-finished inductor product prepared in the step (S6) and the enamel of the enameled wire, and electroplating an electrode at the enamel stripping position to obtain the patch type power inductor.
6. The preparation method according to claim 5, wherein the step S5 specifically comprises: inserting the soft magnetic alloy center posts obtained in the step S1 into the coil obtained in the step S2, then placing the assembly of the coil and the soft magnetic alloy center posts into the magnetic core cavity of the cup-shaped magnet obtained in the step S3, finally placing the flat magnet obtained in the step S4 on the top of the cup-shaped magnet for hot press molding, demolding, baking and curing to obtain the semi-finished inductor.
7. The method according to claim 5, wherein the soft magnetic alloy composite powder material in step S3 and step S4 is a composite material of soft magnetic alloy powder, binder and lubricant.
8. The method according to claim 7, wherein the soft magnetic alloy powder is at least one selected from amorphous soft magnetic alloy powder, nanocrystalline soft magnetic alloy powder, iron-silicon-aluminum alloy powder, iron-silicon-chromium alloy powder, iron-silicon-nickel alloy powder, iron-silicon-aluminum-nickel alloy powder, iron-nickel-aluminum alloy powder, and carbonyl iron powder.
9. The method according to claim 7, wherein the binder is at least one of epoxy resin, polyurethane, silicone resin, amino resin, polyimide, phenol resin, cyanate resin, and acrylic resin; the lubricant is at least one of zinc stearate, magnesium stearate, aluminum stearate, calcium stearate, graphite powder and graphene.
10. The manufacturing method according to claim 5, wherein the flat plate magnet is provided with an electrode slot for leading out a coil end.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114758881A (en) * | 2022-04-18 | 2022-07-15 | 宁波中科毕普拉斯新材料科技有限公司 | Preparation method of chip inductor |
| CN115206643A (en) * | 2022-05-17 | 2022-10-18 | 东莞市三体微电子技术有限公司 | Integrated small-size power inductor and manufacturing method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114758881A (en) * | 2022-04-18 | 2022-07-15 | 宁波中科毕普拉斯新材料科技有限公司 | Preparation method of chip inductor |
| CN115206643A (en) * | 2022-05-17 | 2022-10-18 | 东莞市三体微电子技术有限公司 | Integrated small-size power inductor and manufacturing method thereof |
| CN115206643B (en) * | 2022-05-17 | 2023-05-30 | 东莞市三体微电子技术有限公司 | Integrated small-size power inductor and manufacturing method thereof |
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