JP5141659B2 - Coil component and manufacturing method thereof - Google Patents

Description

  The present invention relates to a coil component and a manufacturing method thereof, and more particularly to a multilayer winding structure of a coil component.

  The most basic method for increasing the inductance in the coil component is to increase the number of turns of the winding, and a multilayer winding structure is preferably employed particularly from the viewpoint of miniaturization of the coil component. For example, Patent Document 1 describes a coil component in which a winding is wound in multiple layers around a core portion of a drum core. Moreover, as shown in Patent Document 2, a coil component having a structure in which a bifilar winding is wound in multiple layers around a core is described (see Patent Document 2). Patent Document 3 describes a coil component having a structure in which banks are wound in multiple layers. In the conventional multilayer winding structure, the winding that cannot be wound in the first layer is wound in the second layer, and the winding that cannot be wound in the second layer is further wound in the third layer. Therefore, the number of turns of the second and higher layers excluding the uppermost layer is generally equal to or less than the first layer, and the remaining number of turns is generally secured in the uppermost layer (see FIG. 7). ).

Japanese Patent Laid-Open No. 2005-44858 JP 2000-30952 A JP 2004-63697 A

  In order to reliably receive radio waves in various frequency bands such as FM radio and One Seg in response to differences in communication systems such as 3G and WLAN in mobile phones, coils that have self-resonant frequencies matched to those frequency bands Is required. For example, in order to obtain a high impedance coil with respect to a relatively low frequency radio wave such as FM radio, it is necessary to match the self-resonant frequency of the coil to the FM band.

  However, as in the conventional multilayer winding structure described above, when the windings that cannot be wound in the first layer by the multilayer winding structure are wound in the second layer with almost the same number of turns as the first layer, one layer There is a problem that the line capacitance between the second wire and the second wire becomes too large, and a desired self-resonant frequency cannot be obtained.

  The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a coil component that can shift the resonance frequency to a low frequency side and thereby obtain a high impedance at a desired frequency. There is to do. Moreover, the objective of this invention is providing the manufacturing method for manufacturing such a coil component.

  As a result of intensive studies to solve the above problems, the inventors of the present application have greatly contributed to the self-resonant frequency of the coil component by the number of turns of the second layer of the coil wound in multiple layers. It has been found that the resonance frequency can be set to a desired frequency band such as an FM band by setting an appropriate number of turns.

  The present invention is based on such technical knowledge, and the coil component according to the present invention is provided in the core part and the drum core having the flange parts provided at both ends of the core part, and the flange part of the drum core. An electrode, and a winding wound around the core in three or more layers, the first layer winding being wound at a first number of turns, and the second layer winding being It is characterized by being wound with a second number of turns that is two or more turns less than the first number of turns.

  The coil component manufacturing method according to the present invention includes a winding core and a drum core having a flange provided at both ends of the winding core, an electrode provided at the flange of the drum core, and three or more layers. A method of manufacturing a coil component wound around a core, having an end connected to an electrode and having a winding, wherein the conductor is wound around the core at a first number of turns, and between the flange Forming a first-layer winding having a first vacant space, and winding the conductive wire on the first-layer winding with a second number of turns that is two or more turns less than the first number of turns. A second layer winding having a second empty space smaller than the first empty space is formed between the first and second empty spaces.

  Since the line capacity of the coil component having the multilayer winding structure is larger than that of the coil component having the single layer winding structure, the self-resonance frequency is lower than that of the single layer winding structure. Therefore, in order to shift the self-resonant frequency of the coil to a low frequency side such as an FM band, it is effective to wind the coil component in multiple layers. In particular, the coil component according to the present invention winds the third layer while leaving the winding space of the second layer with respect to the first layer, so that it is possible to suppress an increase in the inter-wire capacitance of the wire, thereby self-resonance. The frequency can be shifted to an appropriate frequency on the low frequency side without extremely reducing the frequency, and a steep peak of impedance can be obtained at the frequency.

  In the present invention, the number of turns of the second layer winding is preferably 70% or less of the number of turns of the first layer winding. If the number of turns in the second layer is 70% or less in the first layer, the decrease in the number of turns in the second layer with respect to the first layer becomes clear and the line capacitance between the first layer and the second layer is sufficiently reduced. Is done. Therefore, the self-resonant frequency can be shifted to an appropriate frequency on the low frequency side without drastically decreasing, and a steep peak of impedance can be reliably obtained at the frequency.

  In the present invention, the number of turns of the first layer winding is 14 turns, the number of turns of the second layer winding is 9 turns, and the number of turns of the third layer winding is 7 turns. preferable. If each layer has such a number of turns, the condition that the number of turns in the first layer relative to the second layer is 70% is satisfied, and a high impedance can be obtained in a relatively low frequency band of 60 MHz to 1 GHz.

  In the present invention, the winding is wound around the winding core portion with the center aligned, and an empty space is formed between the winding of each layer and the flange portion. The second empty space formed between is wider than the first empty space formed between the first layer winding and the flange, and is between the third layer winding and the flange. It is preferable that the third empty space formed in is wider than the second empty space. According to this, an increase in the capacitance between the wires can be sufficiently suppressed, and a steep peak can be obtained by shifting the resonance frequency to the low frequency side.

  According to the present invention, it is possible to provide a coil component capable of shifting the resonance point to the low frequency side and thereby obtaining a high impedance at a desired frequency. Moreover, according to this invention, the manufacturing method for manufacturing such a coil component can be provided.

1 is a schematic perspective view showing a structure of a coil component 10 according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a coil component 10 taken along line AA ′ in FIG. 1. It is a graph which shows the frequency characteristic of the coil component 10 compared with the conventional coil component. It is a flowchart which shows the manufacturing process of the coil component 10 by 1st Embodiment. It is a schematic perspective view which shows the structure of the coil component 20 by the 2nd Embodiment of this invention. FIG. 6 is a schematic cross-sectional view of the coil component 20 along the line AA ′ in FIG. 5. It is a schematic sectional drawing which shows the structure of the conventional coil component.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view showing the structure of a coil component according to the first embodiment of the present invention. 2 is a schematic cross-sectional view taken along the line AA ′ of FIG.

As shown in FIGS. 1 and 2, the coil component 10 includes a drum core 11 and a winding 12 wound around the drum core 11. The drum core 11 includes a rod-shaped core portion 11a and a pair of flange portions 11b and 11c provided at both ends of the core portion 11a, respectively, and has a structure in which these are integrated. Although not particularly limited, it is preferable to use alumina (nonmagnetic material) or Ni—Zn ferrite (magnetic material, insulator) as the material of the drum core 11. The chip size of the coil component 10 according to the present embodiment is substantially equal to the outer dimension of the drum core 11 and is, for example, 2.0 × 1.2 × 0.7 (mm), but is not limited to this size. However, the width W ₀ of the drum core 11 is preferably not more than 0.6 times the length L ₀ of the drum core 11 (W ₀ ≦ 0.6L ₀ ).

  The surface of the drum core 11 is coated with an insulating material such as paraxylylene, and terminal electrodes 13 are formed on the bottom surfaces, outer side surfaces, and top surfaces of the flange portions 11b and 11c of the drum core 11 via an insulating coat. One end of the winding 12 is connected to the terminal electrode 13 formed on the one flange 11b side, and the other end of the winding 12 is connected to the terminal electrode 13 formed on the other flange 11c side. ing. Specifically, one end and the other end of the winding 12 are connected to the terminal electrode 13 on the upper surface side of the collar portion located on the side opposite to the mounting surface of the coil component 10.

  The winding 12 is wound in multiple layers around the core 11a. When winding the winding 12 with the same number of turns as the multilayer winding, a sufficiently long winding core part 11a must be prepared, and the chip size increases, but when winding the winding 12 in multiple layers Can constitute a very compact chip part. The number of layers of the winding 12 may be any number as long as it is two or more, but three layers are particularly preferable in consideration of the normally required inductance (50 to 440 nH) and prevention of collapse.

  Although not particularly limited, it is preferable to use Cu or the like having high conductivity as the material of the winding 12. The diameter of the winding 12 is preferably 20 to 50 μm, particularly preferably about 30 μm.

The winding 12 having the three-layer structure is aligned and aligned in the axial direction of the core 11a, and the number of turns T2 of the second layer 12 is 2 than the number of turns T1 of the first layer 12. It is less than the number of turns (T ₂ ≦ T ₁ −2), preferably 70% or less (T ₂ ≦ 0.7 T ₁ ) of the number of turns of the first layer winding 12. Further, the number of turns of the third layer winding 12 is smaller than that of the second layer, and is preferably 70% or less (T ₃ ≦ 0.7T ₂ ) of the number of turns of the second layer winding 12. Specific examples of the multilayer winding structure satisfying such conditions are as follows. When the total number of turns of the winding 12 is 30 turns, the first layer has 14 turns, the second layer has 9 turns, and the third layer has 7 turns. It is a turn.

  With such a multilayer winding structure, empty spaces S1 to S3 are formed between each layer of the winding 12 and the one flange 11b, and between each layer of the winding 12 and the other flange 11c. The empty spaces S4 to S6 are formed. In particular, the second empty space S2 formed between the second layer winding 12 and the flange 11b is the first empty space formed between the first layer winding 12 and the flange 11b. The third empty space S3 formed between the third-layer winding 12 and the flange portion 11b is wider than the second empty space S2, which is wider than the space S1. Similarly to the empty spaces S1 to S3, the fifth empty space S5 formed between the second layer winding 12 and the flange portion 11c is between the first layer winding 12 and the flange portion 11c. The sixth empty space S6, which is wider than the formed fourth empty space S4 and is formed between the third layer winding 12 and the flange 11c, is larger than the fifth empty space S5. It is getting wider.

  FIG. 3 is a graph showing the frequency characteristics of the coil component 10 in comparison with a conventional coil component.

  In FIG. 3, the curve G1 is the impedance characteristic of a coil component in which 30 turns are wound in a single layer, and the curve G2 is a three-layer winding structure in which the first layer is 14 turns, the second layer is 13 turns, and the third layer is 3 turns. The curve G3 represents the impedance characteristic of the coil component having a three-layer structure in which the first layer has 14 turns, the second layer has 9 turns, and the third layer has 7 turns. The diameter of the winding is 30 μm for both G1 to G3. As is clear from this graph, in the case of G1 in which the winding 12 is wound in a single layer, the impedance peak exists in the vicinity of 450 MHz, and in the case of G2, the impedance peak exists in the vicinity of 50 MHz. It can be seen that it exists in the vicinity of 100 MHz which is the middle of those frequencies.

  As in the conventional multilayer winding structure, for example, the total number of turns is 30 turns, the first layer is 14 turns, the second layer is 14 turns (or 13 turns in consideration of ease of winding), and further 3 layers When the remaining four turns (or five turns) were used, the line capacitance between the first and second windings was too large, and it was difficult to adjust the self-resonance frequency. However, the self-resonant frequency can be shifted to an appropriate frequency between 60 MHz and 1 GHz by a winding structure in which the number of turns in the second layer is appropriately reduced from that in the first layer. A steep peak of the self-resonant frequency can be obtained in the band.

  FIG. 4 is a flowchart showing the manufacturing process of the coil component 10 according to the present embodiment.

  As shown in FIG. 4, in the manufacture of the coil component 10, first, the drum core 11 and the conducting wire on which the terminal electrode 13 is formed are prepared (step S <b> 11). For example, 14 turns) and the windings are aligned at the center to form the first layer winding (step S12). As a result, a first empty space S1 is formed between the first layer winding and the flange 11b, and a fourth empty space S4 is formed between the flange 11c.

  Next, the conductive wire is overlapped on the first layer winding and wound with the second turn number and center alignment. At this time, the turn number is 70% or less (for example, 9 turns) of the first turn number. (Step S13). Thus, by winding the second layer with the second number of turns smaller than the first number of turns, the first empty space is formed between the second layer winding and the flange portion 11b. A second empty space S4 larger than S1 is formed, and a fifth empty space S5 larger than the fourth empty space S4 is formed between the flange 11c.

  Furthermore, the conductive wire is overlapped on the second layer winding and wound with the third turn number and the center alignment. At this time, the turn number is less than the second layer turn number (for example, 7 turns). (Step S14). Accordingly, a third empty space S3 larger than the second empty space S2 is formed between the third layer winding and the flange 11b, and from the fifth empty space S5 between the flange 11c. A large sixth empty space S6 is formed. Thereafter, the coil component 10 according to the present embodiment is completed by thermocompression bonding the terminal of the winding 12 to the corresponding terminal electrode 13 (step S15).

  As described above, according to this embodiment, since the empty space between the first layer winding and the flanges 11b and 11c increases toward the upper layer, the line capacitance can be reduced. The resonance frequency can be increased. Therefore, a coil component having a high impedance in a desired frequency band such as the FM band can be provided.

  FIG. 5 is a schematic perspective view showing the structure of a coil component according to the second embodiment of the present invention. FIG. 6 is a schematic cross-sectional view taken along the line AA ′ of FIG.

  As shown in FIGS. 5 and 6, the coil component 20 is obtained by winding two windings 12a and 12b in a multilayer bifilar manner. “Bifilar winding” refers to a winding method that improves the magnetic coupling between windings by winding two windings together. In the present embodiment, one end of one winding 12a is connected to one terminal electrode 14a on the flange 11b side, and the other end is connected to one terminal electrode 14c on the flange 11c side. One end of the other winding 12b is connected to one terminal electrode 14b on the flange 11b side, and the other end is connected to the other terminal electrode 14d on the flange 11c side.

  The windings 12a and 12b both have a three-layer structure, and the total number of turns is 30 turns, the first layer is 14 turns, the second layer is 9 turns, and the third layer is 7 turns. With such a winding structure, empty spaces S1 to S3 are formed between each layer of the winding 12 and the one flange 11b, and between each layer of the winding 12 and the other flange 11c. In this, empty spaces S4 to S6 are formed. In particular, the second empty space S2 formed between the second layer winding 12 and the flange portion 11b is the first empty space formed between the first layer winding 12 and the flange portion 11b. The third empty space S3 formed between the third layer winding 12 and the flange 11b is wider than the second empty space S2, which is wider than S1. Similarly to the empty spaces S1 to S3, the fourth empty space S5 formed between the second layer winding 12 and the flange portion 11c is formed between the first layer winding 12 and the flange portion 11c. The sixth empty space S6 formed between the third layer winding 12 and the flange 11c is wider than the fifth empty space S5. It has become.

  Thus, the coil component 20 according to the present embodiment is the same as that of the first embodiment except that the coil component 20 is bifilar wound, and the empty space between the first layer winding and the collar portion is larger as the upper layer. Thus, the line capacitance can be reduced and the resonance frequency can be increased. Therefore, a coil component having a high impedance in a desired frequency band such as the FM band can be provided.

  Although the present invention has been described based on the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. It goes without saying that the present invention is included in the scope of the present invention.

  For example, in the above embodiment, the case where only the drum core 11 is used has been described. However, the shape of the core is not particularly limited, and for example, a drum core and a plate core may be combined. By fixing the plate core to the upper surfaces of the flange portions 11b and 10c of the drum core, the drum core and the plate core can be configured as one closed magnetic circuit, so that the inductance of the coil can be further increased.

  In the above embodiment, the number of turns of the winding is 30. However, the present invention is not limited to 30 turns, and can be appropriately set according to the target inductance. For example, when the total number of turns is 36, the first layer can be 18 turns, the second layer can be 12 turns, and the third layer can be 6 turns. When the total number of turns is 28, the first layer can be 14 turns, the second layer can be 8 turns, and the third layer can be 6 turns.

  Moreover, in the said embodiment, although alumina and Ni-Zn system ferrite were mentioned as a material of the drum core 11, this invention is not limited to these materials, For example, it is also possible to use Mn-Zn system ferrite. It is.

  In the above embodiment, both ends of the winding 12 provided on the upper surface side of the coil component 10 and the upper portion of the winding 12 wound around the winding core portion 11a are exposed. A nonmagnetic resin coating layer may be provided. By forming the coating layer, the upper surface of the coil component 10, particularly the both ends of the thermocompression-bonded winding 12 and the electrode surfaces on the upper surfaces of the flanges 11 b and 11 c to which they are connected, are electrically and mechanically protected can do. Moreover, the winding 12 wound around the winding core part 11a can be bonded and fixed, and the collapse of the winding can be prevented. Furthermore, the suction surface of the mounting nozzle can be provided by flattening the upper surface of the coating layer. As a material for the coating layer, an ultraviolet curable resin or a thermosetting resin can be used.

DESCRIPTION OF SYMBOLS 10 Coil components 11 Drum core 11a Core part 11b, 11c Saddle part 12,12a, 12b Winding 13 Terminal electrode 14a-14d Terminal electrode 20 Coil parts S1-S6 Empty space

Claims (5)

A drum core having a core part and flanges provided at both ends of the core part;
An electrode provided on the flange of the drum core;
A winding wound in a central alignment on the core part over three or more layers,
The first layer winding is wound with a first number of turns, and the second layer winding is wound with a second number of turns that is two or more turns less than the first number of turns , The third layer winding is wound with a third number of turns less than the second number of turns,
An empty space is formed between the winding of each layer and the collar part,
The second empty space formed between the second layer winding and the flange is more than the first empty space formed between the first layer winding and the flange. Wide,
The coil component , wherein a third empty space formed between the third layer winding and the flange is wider than the second empty space .   The coil component according to claim 1, wherein the number of turns of the second layer winding is 70% or less of the number of turns of the first layer winding.   The first layer winding has 14 turns, the second layer winding has 9 turns, and the third layer winding has 7 turns. The coil component according to claim 1 or 2. The coil component according to any one of claims 1 to 3, wherein the self-resonant frequency is 60 MHz to 1 GHz. A drum core having a core part and a flange core provided on both ends of the core part, an electrode provided on the flange part of the drum core, and three or more layers are wound around the core part in a central alignment . A method of manufacturing a coil component having an end connected to the electrode and a winding,
Winding a conducting wire around the winding core portion with a first number of turns to form a first layer winding having a first empty space between the flange portion,
The conducting wire is wound on the first-layer winding with a second number of turns that is two or more turns less than the first number of turns, and is larger than the first empty space between the flanges. Forming a second layer winding with two free spaces ,
The conductive wire is wound around the second layer winding with a third number of turns smaller than the second number of turns, and a third space larger than the second space is formed between the winding and the flange. A method for manufacturing a coil component, comprising forming a third layer winding having a space .

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