JP4320698B2 - Multilayer coil for brushless motor - Google Patents

Description

【００１８】
表１で示した層構成を有する積層コイルの変形（反り量）を評価した。評価方法は、レーザ光線を利用して測定物の高さを非接触で測定することが出来る３次元ＣＮＣ画像測定器を用い、積層コイルの入力、出力端子電極が形成された主面側を縁部と平行に１００μｍピッチで掃引して８０×８０点（６４００点）測定し、その最大値と最小値の差を被測定物の反り量とした。これを各試料毎に１０枚づつ測定して各試料の反り量を平均値、最大値、最小値として表２に示す。実装基板に積層コイルを直接搭載する場合には、その反り量を１５０μｍ以下とするのが好ましいが、本発明の実施例においてはすべて１５０μｍ以下の反り量とすることが出来た。
【００１９】
【表２】

【００２０】
【発明の効果】
本発明によれば、小型・薄型でかつ変形の小さい積層コイルを得る事が出来る。
【図面の簡単な説明】
【図１】 本発明の一実施例に係る積層コイルの斜視図である。
【図２】 本発明の一実施例に係る積層コイルの内部構造を示す分解図である。
【図３】 本発明の一実施例に係る積層コイルの等価回路である。
【図４】 本発明の一実施例に係る積層コイルのコイル接続状態を示す内部構造分解図である。
【図５】 本発明の他の実施例に係る積層コイルの斜視図である。
【図６】 本発明に係る積層コイルの製造方法の一例を示す積層基板の分解斜視図である。
【図７】 本発明に係る積層コイルが複数形成された積層基板の平面図である。
【図８】 本発明の一実施例に係る積層コイルを用いたブラシレスモータの断面図である
【図９】 従来の積層コイルの分解斜視図である。
【符号の説明】
１ 積層コイル
１０ 貫通孔
６０ 第１のコイル極
６１ 第２のコイル極
６２ 第３のコイル極
２００、２０１ａ、２０１ｂ、２０１ｃ、２１０ 第１の接続線路
２５１ａ〜２５１ｈ、２５２ａ〜２５２ｈ、２５３ａ〜２５３ｈ コイル
３００ａ〜３００ｃ 第２のコイル
３１０ａ〜３１０ｃ 変形抑止電極パターン[0001]
[Industrial application fields]
The present invention relates to a laminated coil for a motor that is small and thin and has little deformation.
[0002]
Along with the downsizing of electronic devices, motors used in each electronic device are strongly demanded to be small and thin. As such a motor, for example, in Japanese Patent Laid-Open No. 64-59902, a coil conductor pattern is formed on a green sheet obtained from ceramic powder by , for example, a screen printing technique to form a coil sheet, and a plurality of such sheets are laminated. In addition, a multilayer coil for a brushless motor is disclosed in which a coil conductor pattern is electrically connected by a through hole, and the coil conductor pattern and a green sheet are integrally fired. FIG. 9 shows an exploded perspective view thereof.
[0003]
[Problems to be solved by the invention]
In such a conventional coil, a plurality of coil sheets 61a and 61b are laminated on a green sheet substrate 60 on which external terminal electrodes are formed. Coil Runode thickness is different rectangular portion thickness and the external terminal electrodes are formed of a circular portion formed, a difficult to manufacture, the shape of the laminated coil has poor productivity. Further, in order to obtain the mechanical strength of the external terminal electrode portion 65, it is necessary to make the green sheet 60 substrate on which the coil conductor pattern is not formed thick. As a result, the thickness of the laminated coil is increased, and the external terminal electrode is increased. There is a problem that the portion 65 increases the area of the laminated coil, and as a result, the outer dimension of the brushless motor increases.
[0004]
The coil conductor pattern is made of Ag, Cu, or the like, and the green sheet is a low-temperature sinterable ceramic material mainly composed of, for example, Al ₂ O _3. Yes. Such a green sheet and a coil conductor pattern have a large sintering shrinkage ratio and different shrinkage characteristics. In general, when a green sheet and a conductor pattern formed on the surface thereof are integrally fired, first, the conductor constituting the conductor pattern such as Ag, Cu starts to shrink when reaching the glass transition point. Subsequently, the ceramic of the green sheet starts to shrink when it reaches its glass transition point.
Thus, the contraction is preceded by the conductor pattern, and when the conductor suppresses the crystallization peak point, the contraction is almost completed. On the other hand, ceramics continue to shrink because the crystallization peak point is higher than that of the conductor, and the shrinkage is almost completed at the crystallization peak point.
Ceramics used in laminated coils contain components that tend to become glass during sintering or components that easily form a liquid phase so that sintering can be performed at a relatively low temperature. At the stage of increasing the density in the ceramic, the ceramic itself becomes soft, and deformation occurs due to the uneven distribution of stress in the laminated coil during sintering due to the difference in shrinkage characteristics between the ceramic and the conductor pattern.
In particular, when the arrangement of the conductor pattern in the laminated coil is asymmetric in the lamination direction, there is a difference between the contraction on the side where the conductor pattern is concentrated and the contraction on the side where the conductor pattern is not concentrated, resulting in deformation.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a laminated coil that is small and thin and has little deformation.
[0005]
[Means for Solving the Problems]
The present invention relates to a rectangular flat laminate formed by laminating ceramic green sheets on which conductor patterns are formed and integrally sintering the through holes provided in the laminating direction, with the through holes as the center. A multilayer coil for a brushless motor, in which a plurality of coil poles made of a coil formed of a conductor pattern are arranged, and one main surface of the multilayer body has one input terminal electrode and a plurality of output terminals connected to the coil pole Each terminal electrode is formed at a corner of the laminate that does not substantially overlap with the coil pole in the stacking direction, and overlaps with each terminal electrode on the other main surface facing the main surface in the stacking direction. A deformation-inhibiting electrode pattern that suppresses deformation during sintering is formed in the portion , and the deformation-inhibiting electrode pattern is a laminated coil for a brushless motor that does not have an electrical connection with a coil pole .
The deformation suppressing electrode pattern preferably has an approximate shape to the input terminal electrode and the output terminal electrode. In the present invention, deformation is suppressed by configuring the arrangement of conductor patterns formed in the laminated coil symmetrically in the laminating direction.
Further, if the input terminal and the output terminal are formed at four corners of the main surface so as not to overlap with the coil pole in the stacking direction on one main surface of the rectangular stacked coil, the stacked coil is not substantially enlarged. A laminated coil can be constructed. Furthermore, since the input / output terminals can be formed relatively large, the terminal connection strength with the printed circuit board can be improved, and the empty space of the laminated coil in which no coil pole is formed can be used effectively.
Since the input terminal electrode and the output terminal electrode are formed on the same main surface of the laminated coil, the connection to the printed circuit board (PCB) is easily surface-mounted. The input terminal electrode and the output terminal electrode are preferably LGA (Land Grid Array) and BGA (Ball Grid Array), respectively.
In the present invention, if the input terminal electrode, the output terminal electrode, and the deformation-inhibiting electrode pattern are connected by a through hole or a side electrode formed in the multilayer body, surface mounting is possible on either of the main surfaces of the multilayer coil. Therefore, it is preferable. Further, if the side electrode is formed, the solder can wrap around that portion to further strengthen the connection.
[0006]
[0007]
DETAILED DESCRIPTION OF THE INVENTION
A laminated coil according to an embodiment of the present invention will be described below.
FIG. 1 is a perspective view of a laminated coil according to an embodiment of the present invention. The laminated coil has, on a green sheet having a thickness of several μm~200μm of ceramic material which enables low-temperature co-fired (LTCC material), the desired conductor by printing a conductive paste mainly containing or Ag or Cu becomes coil A plurality of coil poles are integrated by forming a pattern, appropriately laminating green sheets having a conductor pattern, and firing. The green sheet forming the coil is preferably 20 μm or less in order to increase the space factor.
The laminated coil is formed in a rectangular plate shape, and has an input terminal electrode IN and output terminal electrodes OUT1 to OUT3 for connection between the coil pole and an external circuit on its main surface, and the input surface on the other main surface. Deformation suppression electrode patterns 310a to 310d that are approximately the same shape as the output terminal electrode and overlap the input / output terminal electrode in the stacking direction are formed. The input terminal electrode IN and the output terminal electrodes OUT1 to OUT3 are formed at the four corners of the rectangular laminated coil so as not to overlap with the coil poles included in the laminated coil in the laminating direction. Although the shape is not particularly limited, it is preferably formed in as large an area as possible from the viewpoint of securing the soldering strength with the mounting substrate. In this embodiment, the electrode pattern is formed as a substantially triangular electrode pattern. Then, the deformation suppressing electrode pattern is overlapped with the input terminal electrode and the output terminal electrode so as to constitute the laminated coil with good symmetry, and is formed in an approximate shape with the input terminal electrode and the output terminal electrode.
The electrode thickness is preferably formed in the same manner as the input terminal electrode and output terminal electrode, and the thickness is 8 to 25 μm. In the present embodiment, the deformation suppressing electrode pattern is formed only on the main surface of the laminated coil, but it may be included in the laminated coil similarly to the coil. And it is preferable to electrically connect a deformation | transformation suppression electrode pattern, an input terminal electrode, and an output terminal electrode with the through-hole enclosed in a laminated coil, or the side electrode formed in the side surface.
FIG. 5 shows a side electrode from which a castellation is formed at each of the four corners of the laminated coil and from which the main surface on which the input terminal electrode and the output terminal electrode are formed to another main surface on which the deformation suppression electrode pattern is formed. Is formed. If formed in this way, the mounting surface on the mounting substrate can be selected as appropriate, and if there are side electrodes, soldering can be made stronger. The deformation suppression electrode pattern does not necessarily have a shape approximate to that of the input terminal electrode and the output terminal electrode, and a shape that suppresses the deformation may be appropriately set according to the laminated coil.
[0008]
In the laminated coil according to the present invention, the insulation layer thickness between the spiral coils is A, and the insulation of the first coil-unformed region between the spiral coils from the main surface on which the input terminal electrode and the output terminal electrode are formed. When the body layer thickness is B and the insulation layer thickness of the second coil non-formation region between the spiral coils from the other main surface of the laminated coil is C, the insulation layer thickness B of the first conductor pattern non-formation region And the insulator layer thickness A between the spiral coils is 1 ≦ (B / A) ≦ 10, and the insulator layer thickness C in the second coil non-formation region and the insulator layer thickness A between the spiral coils are Is preferably 1 ≦ (C / A) ≦ 10, and the insulator layer thickness B and the insulator layer thickness C are preferably substantially equal.
If the thickness of the insulator layer in the first coil-unformed region and the thickness of the insulator layer in the second coil-unformed region are different, the symmetry of the electrode pattern in the laminated coil is impaired, and the deformation amount is increased. Absent. Further, the thicknesses B and C of the insulating layer in the first coil non-forming region and the insulating layer in the second coil non-forming region are not less than 10 times the thickness A but not less than the insulating layer thickness A between the spiral coils. It is preferable that it is the thickness of this. If the thickness of the insulating layer in the area where the coil is not formed is thinner than the thickness of the insulating layer between the spiral coils, sufficient pressure cannot be applied to the laminated coil during crimping, resulting in structural defects such as delamination. Forcibly crimping is not preferable because the coil is deformed or disconnected, and a crack or the like is generated in the insulating layer between the coils. Further, even if the insulating layer thickness A is formed to be thicker than 10 times, the laminated coil is merely thickened. If the laminated coil has a predetermined thickness, the insulating layer forming the coil must be reduced. As a result, the number of coil turns is reduced, and a desired torque characteristic cannot be obtained.
[0009]
An example of the manufacturing method of the laminated coil which concerns on this invention is demonstrated using FIG.6 and FIG.7. First, by a known sheet forming method such as a doctor blade method, a ceramic slurry made of ceramic powder, a binder, and a plasticizer is applied on a carrier film made of a polyethylene terephthalate film with a uniform thickness, and several tens μm to several hundreds A green sheet of μm is formed. Then, the dried green sheet is cut into a predetermined size with the carrier sheet attached.
The ceramic powder is, for example, a low-temperature sinterable dielectric material containing Al ₂ O ₃ as a main component and at least one of SiO ₂ , SrO, CaO, PbO, Na ₂ O and K ₂ O as a multicomponent, In another example, a low-temperature sinterable dielectric material containing Al ₂ O ₃ as a main component and containing at least one of MgO, SiO _2, and GdO as a multicomponent. In another example, a low-temperature-sinterable magnetic ceramic material containing at least one of Bi ₂ O ₃ , Y ₂ O ₃ , CaCO ₃ , Fe ₂ O ₃ , In ₂ O ₃ and V ₂ O ₅ is provided. The ceramic component is devised to be sintered at low temperature.
In this embodiment, the main component is composed of oxides of Al, Si, Sr, and Ti, and Al, Si, Sr, and Ti are converted into Al ₂ O ₃ , SiO ₂ , SrO, and TiO ₂ , respectively, and a total of 100 masses. % In terms of Al ₂ O ₃ , 10 to 60% by mass, 25 to 60% by mass in terms of SiO2, 7.5 to 50% by mass in terms of SrO, and 20% by mass or less in terms of TiO ₂ , Al, Si, Dielectric ceramics containing Sr and Ti and containing 0.1 to 10% by mass of Bi in terms of Bi ₂ O ₃ were used as subcomponents with respect to the total of 100% by mass. The basic characteristics of this dielectric ceramic are a dielectric constant of 7 to 9, and a three-point bending (sample shape length 36 mm, width 4 mm, thickness 3 mm, fulcrum distance) according to the bending strength test method defined in JIS R 1601. 30 mm) has a bending strength of 240 MPa or more, a Young's modulus of 110 GPa or more, and the LTCC material has a high bending strength and a Young's modulus.
[0010]
A coil (not shown), input / output terminals, and the like, which will be described later, are formed on such a green sheet by a conductor pattern, and are laminated and pressure-bonded in a predetermined order to obtain a flat laminate 300 having a thickness of approximately 0.4 mm. . And the main surface on the opposite side to the main surface on which the conductor patterns 210, 201a, 201b, 201c for connecting the input terminal IN, the output terminals OUT1, OUT2, OUT3, the input terminal and the coil pole of the laminate are formed. The electrode patterns 310a, 310b, 310c, and 310d that do not overlap the coil pole in the stacking direction but overlap the input terminal electrode and the output terminal electrode in the stacking direction and have substantially the same shape are printed or transferred by conductor paste. Formed. In addition, second connection lines 300a, 300b, and 300c that connect in-phase coil poles in series on the same surface are formed. A through hole (not shown) is formed in the green sheet, and a conductor pattern between the sheets is appropriately connected so as to function as a coil pole.
Thereafter, a portion serving as the rotation center of the motor rotation shaft of the laminate was punched out by a mold, or laser processing was performed to form a through hole 10 having a diameter of 2 mm.
Then, a plurality of divided grooves parallel to each other and a plurality of divided grooves 320 perpendicular to the divided grooves 320 were formed on the main surface of the flat laminate with a steel blade so as to have a depth of approximately 0.1 mm. The depth of the dividing groove is appropriately set in the range of 50 μm to 300 μm from the viewpoint of easiness of dividing and handling. Thereafter, the flat molded body was degreased and sintered to obtain a laminated substrate 300 (an assembly of laminated coils) of 65 mm × 60 mm × 0.3 mm. Input / output terminals of laminated coils are formed on the outer surface of the laminated substrate 300, and Ni plating and Au plating are applied thereto by electroless plating. After the plating process, it was divided along the divided grooves to obtain a laminated coil 1 for a brushless motor having an outer dimension of 8 mm × 8 mm × 0.3 mm shown in FIG.
[0011]
Next, referring to FIG. 2, the internal structure of the laminated coil according to one embodiment of the present invention will be described in detail in the order of lamination. This laminated coil is a laminated coil for a brushless motor using a three-phase driving power source, and has an equivalent circuit shown in FIG.
First, second connection lines 300a, 300b, and 300c for connecting in-phase coil poles are formed on the back surface of the lowermost first layer. These second connection lines are arranged at equiangular intervals around a motor rotation shaft, which will be described later, and are formed by two arcuate portions centering on the motor rotation shaft and radially formed from the center of the motor rotation shaft. It has a radial part connecting the two arcuate parts.
In this embodiment, the second connection line is configured as described above, and the in-phase coil poles arranged at the rotationally symmetric position at 180 ° are connected to the rotation center of the motor rotation shaft. By arranging the two arcuate portions on the circumference around the motor rotation axis, the torque characteristics can be improved to a slight extent without hindering the rotation characteristics of the motor. Moreover, although the said 2nd connection line is formed in the laminated body exterior, you may print and form a conductive paste inside a laminated body similarly to a coil pole.
Triangular deformation suppressing conductor patterns 310a, 310b, 310c, and 310d are formed at the four corners of the main surface of the laminated coil. These electrode patterns are formed in a portion overlapping the input terminal electrode and output terminal electrode formed on the other main surface in the stacking direction, and have an approximate shape to the input terminal electrode and output terminal electrode.
[0012]
A plurality of coils are formed on the first layer. The coils are arranged at equiangular intervals around the motor rotation shaft to form a multi-phase coil pole. In the plurality of coils formed in the first layer, six coils 251g, 252g, 253g, 251h, 252h, and 253h serving as three-phase coil poles are formed on the same layer at intervals of 60 °.
The first coil 251h having a through-hole portion (indicated by a black circle in the drawing) wound in the clockwise direction from the inner peripheral side to the outer peripheral side and connected to the coil of the other layer at the outer peripheral end, 252h, 253h, and second coils 251g, 252g, 253g wound in a clockwise direction from the outer peripheral side to the inner peripheral side and having a through-hole portion for connecting to the coil of the other layer at the inner peripheral end portion Composed. The first coil and the second coil are alternately arranged around the motor rotation axis as shown in the figure.
In the present embodiment, the coils at a rotationally symmetric position of 180 ° with respect to the motor rotation shaft are electrically connected in series by the second connection line to form in-phase coil poles. That is, the first coil 251h and the second coil 251g are connected by the second connection line 300a, the first coil 252h and the second coil 252g are connected by the second connection line 300b, and the first coil 253h. And the second coil 253g are connected by the second connection line 300c to constitute coil poles of different phases. That is, the connection line 300a is the midpoint of the second phase coil pole 61 shown in FIG. 3, the connection line 300b is the midpoint of the first phase coil pole 60, and the connection line 300c is the third phase coil pole 62. Each of the midpoints is configured.
[0013]
A second layer on which a plurality of coils are formed is disposed on the first layer. The plurality of coils are formed by forming six coils 251e, 252e, 253e, 251f, 252f, and 253f on the same layer at intervals of 60 ° around the rotation axis of the motor, and winding them by four turns. It is a spiral coil that is turned. Here, if the coil formed in the first layer is the first coil wound clockwise from the inner peripheral side to the outer peripheral side, the coil formed in the second layer overlapping with this coil in the stacking direction Is formed as a second coil wound clockwise from the outer peripheral side to the inner peripheral side, and if the coil formed on the first layer is the second coil, the second coil is disposed above the second coil. A first coil is formed in the two layers, and each is connected by a through hole and connected in the same winding direction.
[0014]
The third layer is configured in the same manner as the first layer and the fourth layer is substantially the same as the second layer, and are sequentially stacked. A spiral coil of the same phase formed in the first to fourth layers and overlapping in the stacking direction includes a first coil wound clockwise from the inner peripheral side to the outer peripheral side, and an outer peripheral end of the first coil. Since it is composed of a second coil that is connected and wound in the clockwise direction from the outer peripheral side to the inner peripheral side, the same winding direction is used, so that the current flows in a constant direction between the first coil and the second coil. It operates as one coil pole to which is applied. In the present embodiment, in order to increase the number of turns of the coil pole and increase the motor torque, the coil poles of the same phase formed in different areas in a plane are electrically wound with one coil for four turns. Connected, the number of coil turns per phase is 32 turns. As for the number of turns of the coil, the desired number of turns of the coil can be easily adjusted by increasing or decreasing the number of layers of each layer on which the coil is formed. As described above, the coils are symmetrically arranged in the stacking direction so that a difference in contraction does not occur as much as possible.
[0015]
Then, on the fifth layer laminated thereon, the same conductive paste as that for forming the coil is printed to connect the input terminal electrode IN, the output terminal electrodes OUT1 to OUT3, and the coil electrode, the first connection line. Formed. The first connection line is an annular conductor portion 210 formed so as to surround the through hole 10 formed in a substantially central portion of the multilayer body, and a first conductor that connects the annular conductor portion and the input terminal. Part 200 and second conductor parts 201a to 201c extending from the annular conductor part 210 and connected to the coil pole.
In this manner, as shown in FIG. 4 by the two-dot broken line, the connection state between the coils is shown, and the first phase coil pole 60 disposed between the input terminal IN and the output terminal OUT1 is formed by the coils 252a to 252h. A second-phase coil pole 61 disposed between the terminal IN and the output terminal OUT2 is formed by the coils 251a to 251h, and a third-phase coil pole 62 disposed between the input terminal IN and the output terminal OUT3 is defined as the coils 253a to 253a. Formed in 253 h.
The center of the through hole 10 formed in the substantially central portion of the laminate substantially coincides with the center of the rotor shaft. The through-hole 10 is formed by punching the laminate with a mold, laser processing, or the like.
As described above, an 8 mm × 8 mm × 0.3 mm laminated coil for a brushless motor was produced. In addition, it is also within the scope of the present invention to form a coat layer with overcoat glass on the main surface of the laminated coil.
[0016]
Through the steps as described above, a laminated coil was manufactured with the layer structure shown in Table 1. In all the laminated coils shown here, the insulator layer thickness between the spiral coils is set to 20 μm in terms of the thickness of the green sheet. In addition, all the thickness in a table | surface is shown by the greece sheet thickness. Sample No. Reference numeral 1 is a comparative example of the present invention in which the first coil pattern non-formed region thickness A and the second coil pattern non-formed thickness B are different from each other and does not have a deformation suppressing electrode pattern. Was attached. Sample No. Stacked configuration of the two-sample No. 1 is an example in which a deformation suppressing electrode pattern is formed on the main surface of the laminated coil. 3 is a reference example in which the first coil pattern non-formed region thickness A and the second coil pattern non-formed thickness B are configured to be equal and have no deformation suppression electrode pattern. No. 4 shows the stacking structure of Sample No. 3 is an example in which a deformation suppressing electrode pattern is formed on the main surface of the laminated coil.
[0017]
[Table 1]

[0018]
The deformation (the amount of warpage) of the laminated coil having the layer configuration shown in Table 1 was evaluated. The evaluation method uses a three-dimensional CNC image measuring device that can measure the height of the object to be measured in a non-contact manner using a laser beam, and borders the main surface side where the input and output terminal electrodes of the laminated coil are formed. Sweep at a pitch of 100 μm parallel to the part and measured 80 × 80 points (6400 points), and the difference between the maximum value and the minimum value was taken as the amount of warpage of the object to be measured. This is measured for every 10 samples, and the warpage amount of each sample is shown in Table 2 as an average value, a maximum value, and a minimum value. When the laminated coil is directly mounted on the mounting substrate, the amount of warpage is preferably 150 μm or less, but in all the examples of the present invention, the amount of warpage could be 150 μm or less.
[0019]
[Table 2]

[0020]
【The invention's effect】
According to the present invention, it is possible to obtain a laminated coil that is small and thin and has little deformation.
[Brief description of the drawings]
FIG. 1 is a perspective view of a laminated coil according to an embodiment of the present invention.
FIG. 2 is an exploded view showing an internal structure of a laminated coil according to an embodiment of the present invention.
FIG. 3 is an equivalent circuit of a laminated coil according to an embodiment of the present invention.
FIG. 4 is an internal structure exploded view showing a coil connection state of a laminated coil according to an embodiment of the present invention.
FIG. 5 is a perspective view of a laminated coil according to another embodiment of the present invention.
FIG. 6 is an exploded perspective view of a multilayer substrate showing an example of a method for manufacturing a multilayer coil according to the present invention.
FIG. 7 is a plan view of a multilayer substrate on which a plurality of multilayer coils according to the present invention are formed.
FIG. 8 is a cross-sectional view of a brushless motor using a laminated coil according to an embodiment of the present invention. FIG. 9 is an exploded perspective view of a conventional laminated coil.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laminated coil 10 Through-hole 60 1st coil pole 61 2nd coil pole 62 3rd coil pole 200, 201a, 201b, 201c, 210 1st connection line 251a-251h, 252a-252h, 253a-253h Coil 300a to 300c Second coils 310a to 310c Deformation inhibiting electrode pattern

Claims (3)

A rectangular plate-shaped laminate formed by sintering integrally with the laminated ceramic green sheets with the conductor pattern is formed, at the center a through hole provided, the through holes in the stacking direction, formed in the conductor pattern A laminated coil for a brushless motor in which a plurality of coil poles made of a coil are arranged,
One main surface of the laminate is provided with one input terminal electrode and a plurality of output terminal electrodes connected to the coil pole, and each terminal electrode is a corner of the laminate that does not substantially overlap the coil pole in the stacking direction. A deformation-inhibiting electrode pattern that suppresses deformation during sintering is formed on each of the portions and overlaps with each terminal electrode on the other main surface facing the main surface in the stacking direction ,
The deformation inhibiting electrode pattern does not have an electrical connection with a coil pole, and is a laminated coil for a brushless motor.   The multilayer coil for a brushless motor according to claim 1, wherein the deformation suppression electrode pattern is formed in an approximate shape with the input terminal electrode and the output terminal electrode.   The brushless motor laminate according to claim 1, wherein the input terminal electrode, the output terminal electrode, and the deformation suppressing electrode pattern are connected by a through hole or a side electrode formed in the laminate. coil.

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