JP2013219088A - Winding type coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a winding type coil for easily setting a target L value and easily suppressing a variation in an L value for each product.SOLUTION: A winding type coil 1 includes cores 2 having flange parts 22 at both ends of a core part 21 in a longitudinal direction, an electrode 4 provided in each of the flange parts 22, and a conductor wire 3 wound around the core part 21 in the shape of a coil. A pair of leader line parts 31 of the conductor wire 3 is adhered to a pair of electrodes 4. The coil part 32 other than each leader line part 31 of the conductor wire 3 has closely wound parts 32a and 32b at both end parts and has a roughly wound part 32c between the closely wound parts. One leader line part 31 continues to the closely wound part 32a, and the other leader line part 31 continues to the closely wound part 32b. Since winding width of the closely wound parts 32a and 32b can be adjusted by adjusting winding width of the roughly wound part 32c, the leader line part 31 is short.

Description

  The present invention relates to a surface mount type wire wound coil suitable as a chip inductor.

  A wire-wound coil used as a chip inductor has a coil portion formed by winding a lead wire a predetermined number of turns around a core made of alumina or the like, and a lead wire portion (winding start end portion and winding end end portion) of this lead wire It is fixed to the electrode provided in the collar part of the core. This type of wire-wound coil is to electrically and mechanically connect the electrode in the flange and the land by soldering or the like in a state where the core flange is mounted on the corresponding land of the mounting board. Therefore, it is designed to be surface-mounted.

  Generally, in this type of wound coil, a conductor is densely wound around a quadrangular cylindrical core portion of a core to form a coil portion, and a pair of lead wires connecting both ends of the coil portion and electrodes. By adjusting the winding width (length along the axial direction) of the coil portion, the winding width of the coil portion necessary for setting the target L value (inductance value) is adjusted. However, the lead wire portion of the conducting wire is a portion that is wound in a direction that is largely inclined with respect to a plane perpendicular to the axial direction of the core, in addition to the winding start end and winding end end that are relatively difficult to fasten to the core. Therefore, misalignment and winding slack are likely to occur in the lead line portion. For this reason, when manufacturing a wound coil such as a chip inductor with a small target L value, the winding width of the coil portion varies due to the displacement or looseness of the lead wire portion of the conducting wire, and it is difficult to set a stable L value. There was a bug.

  In order to solve such a problem, as shown in FIG. 4, a wound-type coil that has been proposed so far as it can be easily set to a target L value and can suppress variation in L value for each product (for example, Patent Document 1). As shown in FIG. 4, the coil 10 includes a core 11 having flanges 11b at both ends in the longitudinal direction of a quadrangular columnar core 11a, and electrodes 12 provided on the bottom surfaces of both flanges 11b. The conductive wire 13 is wound around the winding core portion 11a in a coil shape, and is formed by a coating layer (not shown) or a display sheet attached to the top surface of the core 11, and a winding start end portion of the conductive wire 13; The winding end ends are fixed to the pair of electrodes 12 as lead lines 14 respectively. A portion excluding each lead wire portion 14 of the conducting wire 13 is a coil portion 15, and the coil portion 15 includes a densely wound portion 15 a and a roughly wound portion 15 b. The closely wound portion 15a and the coarsely wound portion 15b are connected to each other, and the lead wire portion 14 fixed to one electrode 12 is continuous with the closely wound portion 15a, and another lead wire fixed to the other electrode 12 is connected. The portion 14 is continuous with the coarsely wound portion 15b.

  Since the winding type coil 10 schematically configured in this manner can adjust the winding width of the densely wound portion 15a necessary for setting the target L value by adjusting the winding width of the coarsely wound portion 15b, the lead wire It is possible to set the part 14 short and to suppress position shift and winding slack.

JP 2007-115761 A

  However, even if the conventional wire-wound coil 10 shown in FIG. 4 can shorten the lead-out wire portion 14, the wire 13 is roughly wound around one end in the longitudinal direction of the core portion 11a of the core 11 to roughly wind it. Since the portion 15b is formed, the coarse winding portion 15b is likely to be misaligned or loosened. That is, since the coarsely wound portion 15b of the conducting wire 13 is wound in a direction that is largely inclined with respect to a plane orthogonal to the axial direction of the core 11 like the lead wire portion 14, the coarsely wound portion 15b As a result, the lead wire portion 14 at the end of the winding is extended as it is, so that there is a possibility of causing the same positional shift and loosening as the lead wire portion 14. Therefore, the conventional wound coil 10 disclosed in Patent Document 1 has a problem that the effect of suppressing variation in the L value is low.

  The present invention has been made in view of the actual situation of the prior art, and an object of the present invention is to provide a wound coil that can be easily set to a target L value and can easily suppress variation in L value for each product. There is.

  In order to achieve the above object, the present invention provides a core having a flange having a larger diameter than the core at both ends in the longitudinal direction of the rod-shaped core, and electrodes provided on the pair of flanges, respectively. And a conductive wire wound in a coil on the winding core, and a winding-type coil in which a winding start end and a winding end end of the conductive wire are fixed to a pair of the electrodes as a pair of lead wire portions The coil portion excluding the pair of lead wire portions of the conductive wire is composed of a plurality of densely wound portions that are closely wound and at least one roughly wound portion that is roughly wound. One of the lead wire portions is continuous with any one of the closely wound portions, and the other is continuously connected with another closely wound portion.

  In this way, the coil portion is configured by always connecting the closely wound portion to the lead wire portion (winding end portion or winding end end portion) of the conducting wire, and interposing the coarsely wound portion between different densely wound portions. Since the winding type coil can adjust the winding width of the dense winding portion necessary for setting the target L value by adjusting the winding width of the coarse winding portion, the pair of lead wire portions can be shortened. Position shift and winding slack can be suppressed. Also, the coarse winding part of the coil part is continuous with the dense winding part at both ends, and is not continuous with the winding start end part or winding end end part. The possibility of doing is low. Therefore, this winding type coil can be easily set to the target L value, and there is little variation in the L value due to the displacement of the conducting wire or the loosening of the winding.

  In the above-described wound coil, the core portion of the core has a quadrangular prism shape, and the two closely wound portions wound at least at both ends in the longitudinal direction of the core portion are connected to each other. When the coil portion is constituted by one coarse winding portion, the winding operation of the conductive wire for setting the target L value is not complicated, and it is not necessary to increase the size of the core. Thus, a desired wound coil can be easily manufactured.

  The coil of the present invention is composed of a plurality of densely wound portions in which the coil portion excluding each lead wire portion of the conductive wire is densely wound, and at least one coarsely wound portion roughly wound, Since each of the pair of lead wire portions is connected to the densely wound portion, the pair of lead wire portions can be shortened to suppress misalignment and loosening. In addition, it is unlikely that displacement or slackening will occur in the coarsely wound portion formed between the densely wound portions. By adjusting the winding width of this coarsely wound portion, the winding width of the densely wound portion can be adjusted. Yes. That is, this winding type coil can be easily set to the target L value, and there is little variation in the L value due to the displacement of the conducting wire or the loosening of the winding. Therefore, a wire-wound coil having a stable L value can be manufactured with a high yield.

1 is an external view of a wire wound coil according to an embodiment of the present invention. It is a side view which abbreviate | omits and shows the winding type coil of FIG. It is a histogram which shows the dispersion | variation in L value of the winding type coil of FIG. 2, and a comparative example. It is a side view of the winding type coil which concerns on a prior art example.

  Hereinafter, embodiments of the invention will be described with reference to the drawings. First, the configuration of the wound coil according to the embodiment of the present invention will be described with reference to the external view of FIG. 1 and the side view of FIG.

  1 and 2 is a surface mount type chip inductor. The winding coil 1 includes a core 2 having flanges 22 at both ends in the longitudinal direction of a core part 21 and both flanges 22. The electrode 4 provided on the bottom surface of each wire, and the lead wire 3 wound around the winding core portion 21 in a coil shape and having the winding start end portion and the winding end end portion fixed to the pair of electrodes 4 as a pair of lead wire portions 31. And the coating layer 5 applied so as to cover the conductive wire 3 on the top surface side of the core 21 and the display sheet 6 attached to the top surface of the core 2. However, in FIG. 2, the coating layer 5 and the display sheet 6 are not shown. In the wound coil 1, a portion excluding each lead wire portion 31 of the conducting wire 3 is a coil portion 32. The coil portion 32 includes two closely wound portions 32a and 32b and one coarsely wound portion 32c interposed between both closely wound portions 32a and 32b. The densely wound portion 32 a on one end side of the coil portion 32 is continuous with one lead wire portion 31, and the densely wound portion 32 b on the other end side of the coil portion 32 is continuous with the other lead wire portion 31.

  The core 2 is formed by molding a ceramic material such as ferrite or alumina into an H shape when viewed from the side (see FIG. 2). The core portion 21 of the core 2 has a quadrangular prism shape, and the flange portions 22 at both ends of the core 2 are larger in diameter than the core portion 21. The bottom surface of each flange 22 is a surface facing a mounting substrate (not shown), and the wound coil 1 is surface-mounted by soldering the electrode 4 provided on the bottom surface to a corresponding land on the mounting substrate. The electrode 4 is formed by performing nickel plating or solder plating on an electrode layer such as Ag or Ag-Pd.

  The conducting wire 3 is made of a polyurethane-coated electric wire or the like. The conducting wire 3 is wound around the core portion 21 of the core 2 by a dedicated machine (not shown), and the leading end and the terminating end (both corresponding to the ends of the lead wire portion 31) of the conducting wire 3 are fixed to the electrode 4 by soldering or the like. Is done. In the densely wound portions 32a and 32b of the coil portion 32, the conducting wire 3 is wound in a direction substantially perpendicular to the axial direction of the core 2, and the adjacent conducting wires 3 are in close contact with each other or are in close contact with each other at a narrow pitch. It is wound around. However, in the coarsely wound portion 32c of the coil portion 32, the conductive wire 3 is wound in a direction that is largely inclined with respect to a plane orthogonal to the axial direction of the core 2, and the adjacent conductive wires 3 are spaced apart with a wide pitch. Coarsely wound. The coil portion 32 is formed in a coil shape in which a densely wound portion 32a on one end side and a densely wound portion 32b on the other end side are connected by a coarsely wound portion 32c. Since the winding width of the densely wound portions 32a and 32b is adjusted by adjusting the winding width of the coarsely wound portion 32c, the lead wire portion 31 is shortened. Therefore, as shown in FIG. 2, both ends of the coil portion 32 are located in the immediate vicinity of the flange portion 22 (near both ends in the longitudinal direction of the core portion 21).

  The coating layer 5 is made of an adhesive material such as an epoxy resin type or an acrylic resin type, and is applied to the top surface side of the core part 21 to protect the coil part 32. A display sheet 6 that displays the L value of the wound coil 1 is attached to the top surface side of the core 2 by using the adhesive force of the coating layer 5.

  FIG. 3 (a) is a histogram showing the result of measuring the dispersion of the L value by sampling 100 pieces after manufacturing a large number of wound coils 1 with the target L value set at 252.682nH (nanohenry). is there. The average of actual L values of 100 samples of the wound coil 1 was 252.939 nH (ΔL = 0.10%), and the standard deviation σ was 0.333. Therefore, 3σ widely adopted in process management is 1.00.

  FIG. 3B is a histogram showing the results of measuring the variation of the L value by sampling 100 winding coils of the comparative example, which were also manufactured with the target L value set at 252.682 nH. This comparative example is a winding coil (see FIG. 4) having a conventional structure in which one end side of the coil portion is a coarse winding portion and the other end side is a dense winding portion, and the average of actual L values of 100 samples is 252. .285 nH (ΔL = 0.16%). The standard deviation σ was 0.548, and 3σ was 1.64.

  As is clear from these measurement results, when the wound coil 1 according to the present embodiment is compared with the comparative example, the average of the actual L value is close to the target L value in the wound coil 1 and each product is different. The variation of the L value is very small. Therefore, it was confirmed that the wound coil 1 having a stable L value could be manufactured with a high yield.

  As described above, the coil part 32 of the wire-wound coil 1 according to the present embodiment includes the tightly wound part 32 a that is continuous with the one lead line part 31 and the tightly wound part 32 b that is continuous with the other lead line part 31. The winding width of the densely wound portions 32a and 32b necessary for setting the target L value by adjusting the winding width of the roughly wound portion 32c. Can be adjusted. For this reason, in the winding coil 1, the pair of lead wire portions 31 are shortened to suppress misalignment and winding slack. Further, since the coarsely wound portion 32c of the coil portion 32 is interposed between the closely wound portions 32a and 32b and is not continuous with the winding start end portion or the winding end end portion, the coarse winding portion 32c is displaced or loosened. Is unlikely to occur. That is, the winding coil 1 can be easily set to the target L value, and there is little variation in the L value due to the positional deviation or winding slack of the conducting wire 3. Therefore, the winding type coil 1 having a stable L value can be manufactured with a high yield, and improvement in reliability and cost reduction can be expected.

  In the present embodiment, the coil portion 32 has a simple configuration including the densely wound portions 32a and 32b at both ends and one coarsely wound portion 32c interposed therebetween, so that even if the core 2 is small, The winding work of the conducting wire 3 for setting to the target L value is not complicated. Therefore, a desired wound coil 1 suitable as a chip inductor can be easily manufactured.

  However, as long as both ends are closely wound portions, the coil portion may have a configuration in which two or more coarsely wound portions or other closely wound portions are interposed inside the coil portion. For example, the above embodiment can be applied to the case where the coil portion is configured by continuing the coarsely wound portion inside the densely wound portion at both ends and interposing another densely wound portion between the two coarsely wound portions. You can expect almost the same effect as the example.

DESCRIPTION OF SYMBOLS 1 Winding type coil 2 Core 3 Conductor 4 Electrode 21 Winding core part 22 Gutter part 31 Lead wire part 32 Coil part 32a, 32b Closely wound part 32c Roughly wound part

Claims (2)

A core having a collar part larger in diameter than the core part at both longitudinal ends of the rod-shaped core part, electrodes provided on the pair of collar parts, and a coil wound around the core part. In a wound coil in which a winding start end and a winding end end of the conducting wire are fixed to a pair of the electrodes as a pair of lead wire portions,
The coil portion excluding the pair of lead wire portions of the conductive wire is composed of a plurality of densely wound portions that are closely wound and at least one roughly wound portion that is roughly wound. One of the lead wire portions is made continuous with any one of the closely wound portions, and the other is made continuous with another of the closely wound portions.   In Claim 1, the said core part is a quadrangular prism shape, and connects the two said closely wound parts and the two said closely wound parts wound around at least both ends in the longitudinal direction of this core part. The coil part is constituted by one of the coarsely wound portions.