JP6413209B2 - Multilayer coil parts - Google Patents

Description

  The present invention relates to a laminated coil component.

  As a conventional multilayer coil component, for example, one described in Patent Document 1 is known. The multilayer coil component described in Patent Document 1 includes an element body and a coil arranged in a spiral shape within the element body, and the coil has an inner diameter that expands in a tapered shape near the openings at both ends of the coil. Has been placed. Thereby, in this laminated coil component, the magnetic path cross-sectional area of the closed magnetic path that penetrates the coil is equalized as a whole, and the direct current superposition characteristics are improved.

JP 2004-14549 A

  In the laminated coil component described in Patent Document 1, since the cross-sectional area of the closed magnetic path that penetrates the coil is generally equalized, when the element body is viewed from the height direction, the outer shape of the coil It is necessary that the shape and the shape of the element body have a square shape. Therefore, the multilayer coil component described in Patent Document 1 inevitably has a low degree of design freedom. In the multilayer coil component, it is necessary to design the shape of the coil and the shape of the element body according to the purpose of use, and it is required to improve the DC superposition characteristics while ensuring the degree of freedom of design. In addition, in the multilayer coil component, it is desired to reduce the height because of the requirement for embedding mounting on a mounting substrate.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a laminated coil component that can improve the DC superimposition characteristics and reduce the height of the element body.

  The laminated coil component according to the present invention has a substantially rectangular parallelepiped shape whose length in the height direction is smaller than the length in the longitudinal direction and the length in the width direction, and a pair of end faces facing each other in the longitudinal direction. A pair of first side faces extending in the longitudinal direction so as to connect the pair of end faces and facing each other in the height direction, and extending in the height direction so as to connect the pair of first side faces and facing each other in the width direction. An element body having a pair of second side surfaces and a plurality of magnetic layers laminated, and a plurality of coil conductors are electrically connected to form a spiral shape with a central axis along the height direction A coil disposed in the element body, wherein the coil has an inner space in the longitudinal direction equal to or greater than an inner space in the width direction when viewed from the height direction. In the cross-section along the center axis The distance between the end located outside and the second side close to the end is d1, and the distance between the end located outside the coil in the height direction and the first side close to the end is d2. When the distance between the end located inside the coil and the central axis in the width direction is d3, the relationship d1 = d2 = d3 is satisfied.

  The present inventors paid attention to the step of generating magnetic saturation that contributes to a decrease in the inductance value in the DC superposition characteristics of the multilayer coil component. In the coil arranged in the element body, the inside of the corner part (the inside of the part where the side intersects when looking at the coil from the height direction) is easy to concentrate the magnetic flux, and early at low current Since magnetic saturation occurs, it contributes to the reduction of the inductance value at an early stage. When the current value increases, the concentration of magnetic flux spreads in each part, and the magnetic flux density increases, so that magnetic saturation can occur. In view of such a phenomenon, the present inventors pay attention to late magnetic saturation accompanying an increase in current value, and can reduce the speed at which magnetic saturation occurs by generating this magnetic saturation in a balanced manner in the element body. I found. Therefore, in the laminated coil component, the coil arrangement is set so as to satisfy the relationship of d1 = d2 = d3 when viewed in a cross section along the width direction and passing through the central axis. Thereby, in the multilayer coil component, the distribution of the magnetic flux density can be equalized. Thereby, compared with the case where the distribution of magnetic flux density is biased, magnetic saturation occurs in a well-balanced manner. Therefore, in the multilayer coil component, the rate of decrease in the inductance value can be alleviated, and the direct current superposition characteristics can be improved.

  In addition, the laminated coil component may be configured to satisfy the relationship d1 = d2 = d3, and the distance d2 between the end located outside the coil in the height direction and the first side surface close to the end. Can be reduced. Therefore, in the multilayer coil component, if the distance d2 is reduced, the dimension in the height direction can be reduced, and the height of the element body can be reduced.

  In one embodiment, a nonmagnetic part may be arranged between coil conductors facing in the height direction. Thereby, in the multilayer coil component, the concentration of magnetic flux can be suppressed by the nonmagnetic part, and the occurrence of magnetic saturation can be further suppressed.

  According to the present invention, the direct current superimposition characteristics can be improved and the height of the element body can be reduced.

It is a perspective view which shows the multilayer coil component which concerns on one Embodiment. It is a figure which shows the cross-sectional structure along the II-II line | wire in FIG. It is a figure which shows typically the coil seen from the height direction. It is a graph which shows the relationship between a direct current and an inductance value. It is a graph which shows the relationship between a direct current and an inductance value. It is a figure which shows distribution of magnetic flux density. It is a figure which shows distribution of magnetic flux density. It is a figure which shows distribution of magnetic flux density. It is a figure which shows a direct current | flow superimposition characteristic typically. It is a figure which shows the cross-sectional structure of the laminated coil which concerns on other embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a perspective view showing a laminated coil component according to an embodiment. FIG. 2 is a diagram showing a cross-sectional configuration along the line II-II in FIG. A multilayer coil component 1 shown in FIGS. 1 and 2 is, for example, a multilayer inductor. The laminated coil component 1 includes a substantially rectangular parallelepiped element 2, terminal electrodes 3 and 4 disposed at both ends in the longitudinal direction of the element 2, a coil 5 disposed inside the element 2, It has.

  The element body 2 has a pair of end faces 2a, 2b facing in the longitudinal direction and parallel to each other, and a pair of main faces (first side faces) 2c extending so as to connect the pair of end faces 2a, 2b and facing each other. 2d and a pair of side surfaces (second side surfaces) 2e and 2f extending so as to connect the pair of main surfaces 2c and 2d and facing each other. The end surfaces 2a and 2b, the main surfaces 2c and 2d, and the side surfaces 2e and 2f have a substantially rectangular shape.

  In the element body 2, the interval (height T) between the pair of main surfaces 2c and 2d is smaller than the interval (width W) between the pair of side surfaces 2e and 2f (T <W). The distance (width W) between the pair of side faces 2e and 2f is smaller than the distance (length L) between the pair of end faces 2a and 2b (T <W <L). That is, the element body 2 has a smaller length in the height direction than a length in the longitudinal direction and a length in the width direction. The element body 2 is set to have a length L of about 1.8 mm, a width W of about 0.8 mm, and a height T of about 0.33 mm, for example. Alternatively, the element body 2 may be set to have a length L of about 1.0 mm, a width W of about 0.5 mm, and a height T of about 0.33 mm, for example. The dimensional ratio of the element body 2 shown in FIGS. 1 and 2 does not necessarily match the above numerical values.

  The element body 2 is a laminated body formed by laminating a plurality of ceramic layers (magnetic body layers). The ceramic layer functions as an insulator having electrical insulation. The thickness of the ceramic layer is, for example, about 60 μm. The element body 2 is formed by firing a ceramic layer. In the actual laminated coil component 1, the layers of the ceramic layers are integrated so as to be invisible.

  The terminal electrode 3 is formed so as to cover one end face 2a and main edges 2c, 2d and side faces 2e, 2f that are orthogonal to the end face 2a. The terminal electrode 3 is electrically connected to one end of the coil 5. The terminal electrode 4 is formed so as to cover a part of each edge of the main surface 2c, 2d and side surfaces 2e, 2f orthogonal to the other end surface 2b and the end surface 2b. The terminal electrode 4 is electrically connected to the other end of the coil 5. The arrangement positions and shapes of the terminal electrodes 3 and 4 may be set as appropriate according to the design.

  The coil 5 is configured by electrically connecting a plurality of coil conductors 7. Each of the coil conductors 7 is electrically connected by a through-hole electrode (not shown), and the coil 5 is formed in a spiral shape in the element body 2. The coil 5 has a central axis AX along the stacking direction of the coil conductor 7 and the ceramic layer (opposite direction of the main surfaces 2c and 2d) and the central axis AX when viewed from the height direction of the element body 2. AX is located at the center of the element body 2. Each coil conductor 7 is formed of a conductive paste mainly composed of Ag or Ni. The element body 2 is formed by alternately laminating ceramic layers and coil conductors 7 and firing them simultaneously.

  FIG. 3 is a diagram schematically showing the coil viewed from the height direction. In FIG. 3, the terminal electrodes 3 and 4 are not shown. As shown in FIG. 3, the coil 5 has an annular shape and has an outer shape that is substantially rectangular. The longitudinal direction of the coil 5 is arranged along the longitudinal direction of the element body 2. The inner distance d5 in the longitudinal direction of the coil 5 is not less than the inner distance d4 in the width direction (d5 ≧ d4). In the present embodiment, the inner distance d5 in the longitudinal direction of the coil 5 is the inner distance in the width direction. It is larger than d4 (d5> d4). That is, the coil 5 has a longer side extending along the longitudinal direction of the element body 2 than a side extending along the width direction of the element body 2.

As shown in FIG. 2, in the laminated coil component 1, when viewed in a cross section along the width direction and passing through the central axis AX, an end portion 5a located outside the coil 5 in the width direction and a side surface 2e adjacent to this 5a. (2f) between the end portion 5b (upper surface and lower surface) located on the outer side (uppermost portion, lowermost portion) of the coil 5 in the height direction and the main surface 2c (2d) adjacent to the end portion 5b. The distance d2 and the distance d3 between the inner end 5c in the width direction of the coil 5 and the central axis AX satisfy the following relationship.
d1 = d2 = d3
That is, when the coil 5 is viewed in a cross-section along the width direction and passing through the central axis AX, the coil 5 is arranged at the center of the element body 2 when viewed in two parts around the central axis AX. Has been.

The distance d4 between the inner ends 5c of the coil 5 is twice the distance d3 between the inner end 5c of the coil 5 and the central axis AX. Therefore, the distance d1, the distance d2, and the distance d4 satisfy the following relationship.
d1 = d2 = (d4 / 2)
That is, the inner width of the coil 5 is twice the distance d1 between the end 5a and the side surface 2e (2f) of the coil 5 and the distance d2 between the end 5b of the coil 5 and the main surface 2c (2d). Is set to The cross-sectional shape (width, thickness) of the coil 5 may be set as appropriate according to the design.

  Then, the effect of the laminated coil component 1 which concerns on this embodiment is demonstrated. 4 and 5 are graphs showing the relationship between the direct current and the inductance value (DC superposition characteristics). 4 and 5 show the results of simulation. 4B shows a part of the graph shown in FIG. 4A extracted (enlarged), and FIG. 5B shows a part of the graph shown in FIG. 5A extracted. ing. 4 and 5, the horizontal axis indicates IDC (direct current) [mA], and the vertical axis indicates L (inductance value) [uH].

  4 and 5, a line “1-1-1.0” indicates a case where the ratio of the interval d1, the interval d2, and the interval d4 (d3 × 2) is “1: 1: 1”. Similarly, a line “1-1-2.0” indicates a configuration with a ratio of “1: 1: 2”, which indicates the configuration of the present embodiment. A line “1-1-3.0” indicates a configuration with a ratio of “1: 1: 3”. 4 and 5, the result of the multilayer coil component 1 of the present embodiment is indicated by a solid line, and the result of another multilayer coil component of the comparative example is indicated by a broken line and a two-dot chain line.

  As shown in FIGS. 4B and 5B, in the multilayer coil component 1 of the present embodiment, a value of L is secured for the direct current as compared with other multilayer coil components of the comparative example. Has been. Therefore, the multilayer coil component 1 is excellent in that it satisfies the relationship of d1 = d2 = d3 (d4 / 2) when viewed in a cross section along the width direction of the element body 2 and passing through the central axis AX. DC superimposition characteristics can be obtained.

  6-8 is a figure which shows distribution of magnetic flux density. 6 to 8 show the results of simulation. 6 to 8 show the distribution of magnetic flux density when the element body 2 is viewed in a cross section along the width direction.

  FIG. 6 shows a magnetic flux density distribution in a configuration in which the ratio of the distance d1, the distance d2, and the distance d4 is “1: 1: 1”. FIG. 7 shows a magnetic flux density distribution in a configuration in which the ratio of the interval d1, the interval d2, and the interval d4 is “1: 1: 3”. FIG. 8 shows the distribution of magnetic flux density in a configuration in which the ratio of the interval d1, the interval d2, and the interval d4 is “1: 1: 2” (the laminated coil component 1 of the present embodiment). 6 to 8, the portion having a high magnetic flux density is a portion having a high color density. 6 to 8 are partially different from the configuration of the present embodiment described above (configuration shown in FIG. 2), but the distribution of magnetic flux density is the same as that shown in FIG. It is the same.

  As shown in FIG. 6, in the configuration in which the ratio of the interval d1, the interval d2, and the interval d4 is “1: 1: 1”, the interval inside the coil 5 is small. It is close. As shown in FIG. 7, in the configuration in which the ratio of the interval d1, the interval d2, and the interval d4 is “1: 1: 3”, the interval inside the coil 5 is large, so the magnetic flux density distribution is outside the coil 5. It is close. In the configuration shown in FIGS. 6 and 7, the portion where the magnetic flux density is high is magnetically saturated before the other portions. For this reason, the occurrence of magnetic saturation varies. On the other hand, as shown in FIG. 8, in the configuration of the present embodiment (configuration in which the ratio of the interval d 1, the interval d 2, and the interval d 4 is “1: 1: 2”), the magnetic flux density is uniform in the element body 2. Distributed. Thereby, in the laminated coil component 1, magnetic saturation occurs with a good balance. Therefore, in the multilayer coil component 1, as shown in FIGS. 4 and 5, the rate of decrease in the inductance value can be reduced.

  FIG. 9 is a diagram schematically showing the DC superposition characteristics. In the coil 5 arranged in the element body 2, the magnetic flux tends to concentrate on the inside of the corner portion, and early magnetic saturation occurs at a low current. Therefore, as shown in FIG. Contribute to the decline early. When the current value increases, the concentration of magnetic flux spreads in each part, the concentration of magnetic flux spreads in each part, and the magnetic flux density increases, so that magnetic saturation can occur. The present inventors pay attention to the late magnetic saturation accompanying the increase in the current value, for example, a portion surrounded by A2 shown in FIG. 9, and balance the occurrence of magnetic saturation in the portion surrounded by A2 in the element body 2. It has been found that by generating well, the speed at which magnetic saturation occurs can be relaxed and excellent DC superposition characteristics can be obtained.

  Therefore, in the present embodiment, the arrangement of the coils 5 is set so as to satisfy the relationship of d1 = d2 = d3 when viewed in a cross section along the width direction and passing through the central axis AX. Thereby, in the multilayer coil component 1, the coil 5 is arranged in a well-balanced manner in the element body 2 when viewed in a cross section along the width direction and passing through the central axis AX. Therefore, as shown in FIG. Distribution can be equalized. Thereby, compared with the case where the distribution of magnetic flux density is biased, magnetic saturation occurs in a well-balanced manner. Therefore, in the multilayer coil component 1, the rate of decrease in the inductance value can be relaxed, and the direct current superimposition characteristics can be improved.

  The multilayer coil component 1 may be configured to satisfy the relationship d1 = d2 = d3, and the distance d2 between the end portion 5b of the coil 5 and the main surfaces 2c, 2d can be reduced. Therefore, in the multilayer coil component 1, if the distance d2 is reduced, the dimension in the height direction can be reduced, and the height of the element body 2 can be reduced.

  The present invention is not limited to the above embodiment. For example, in addition to the above-described embodiment, as shown in FIG. 10, the nonmagnetic body portion 10 may be disposed between the coil conductors 7 and 7. Examples of the non-magnetic body portion 10 include those obtained by firing a paste (green sheet) in which alumina powder is mixed with glass. In the element body 2 </ b> A, the concentration of the magnetic flux can be suppressed and the occurrence of magnetic saturation can be further suppressed by disposing the nonmagnetic body portion 10. In addition, arrangement | positioning of the nonmagnetic body part 10 is not limited to the structure shown in FIG.

  In the above embodiment, as illustrated in FIG. 3, the coil 5 has a rectangular shape, but the coil 5 may have a square shape, an elliptical shape, or the like. Moreover, the corner | angular part of the coil 5 may be curving.

  DESCRIPTION OF SYMBOLS 1 ... Multilayer coil component, 2, 2A ... Element body, 2a, 2b ... End face, 2c, 2d ... Main surface (first side surface), 2e, 2f ... Side surface (second side surface), 5 ... Coil, 7 ... Coil Conductor, 10 ... non-magnetic part, AX ... central axis.

Claims (1)

A substantially rectangular parallelepiped shape having a length in the height direction that is smaller than the length in the longitudinal direction and the length in the width direction, and a pair of end faces facing each other in the longitudinal direction and the pair of end faces are connected to each other. A pair of first side surfaces extending in the longitudinal direction and facing each other in the height direction, and a pair of first side surfaces extending in the height direction so as to connect the pair of first side surfaces and facing each other in the width direction An element body having two side surfaces and a plurality of magnetic layers laminated,
A plurality of coil conductors electrically connected to each other and configured in a spiral shape, and a coil disposed in the element body so that a central axis is along the height direction,
The coil has an inner interval in the longitudinal direction that is greater than or equal to an inner interval in the width direction when viewed from the height direction.
Between the coil conductors facing in the height direction, a non-magnetic part is disposed and the magnetic layer is not disposed,
When viewed in a cross section along the width direction and passing through the central axis, the distance between the end located outside the coil and the second side surface adjacent to the end in the width direction is d1, the height direction The distance between the end located outside the coil and the first side surface close to the end is d2, and the distance between the end located inside the coil in the width direction and the central axis is d3. If
d1 = d2 = d3
A laminated coil component characterized by satisfying the above relationship.