JP2006066470A - Coil device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil device which can secure sufficient thermal stability, shock resistance and vibration resistance also in a severe application of a using environment such as an in-vehicle coil device, etc. by raising heat dissipation and improving thermal stability in a characteristic. <P>SOLUTION: An insulating resin sheathing member 7 covers a core 10 and a winding 4. Terminals 51 and 52 are parts for connecting the terminal of the winding 4, made of one metal plate, fixed at one-side ends to terminal mounting parts 21 and 22 of the core 10, and have first and second bent parts F1 and F2 between one end and the other end. The first and second bent parts F1 and F2 are located outside the insulating resin sheathing member 7. The insulating resin sheathing member 7 is roughened on at least the part of the front surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ferrite core and a coil device using the ferrite core. The coil device according to the present invention includes an antenna applicable to a vehicle-mounted transponder or the like, or an inductor or choke coil for communication equipment.

  Various types of coil devices have been proposed and put into practical use. As one of them, recently, a coil device applicable as a vehicle-mounted antenna or a transponder has been proposed. In a coil device applied to such a use, a ferrite core having a good high frequency characteristic is generally used. Then, a coil having a necessary number of turns is wound around the ferrite core, and the coil terminal is connected to metal terminals provided at both ends of the ferrite core in the longitudinal direction.

  As the ferrite core, an elongated core having a large length when viewed in the coil winding axis direction is used so that the inductance value, Q value, self-resonant frequency characteristics, etc. required for this type of coil device satisfy the required values. It is common.

  However, the ferrite core is a brittle sintered body and is inherently vulnerable to shock and vibration. In addition, for the reasons described above, the shape must be elongated and weak against shock and vibration. For this reason, in the case of a vehicle-mounted coil device that is constantly exposed to shock and vibration, it is important how to realize a structure excellent in shock resistance and vibration resistance.

  From this point of view, when a known technique is examined, for example, Patent Document 1 discloses a coil device that is entirely covered with a resin mold.

  Patent Document 2 discloses a coil device that is improved in impact resistance and vibration resistance by covering the whole with an insulating resin and by devising the shape of the ferrite core, the terminal structure, and the like.

Among these prior arts, in particular, according to Patent Document 2, a quite satisfactory result can be expected even in applications where the use environment is severe, such as a vehicle-mounted coil device.
JP-A-7-130556 Japanese Patent Laid-Open No. 2003-318030

  The present invention further improves the above-described prior art, and in particular, enhances heat dissipation, improves the thermal stability of characteristics, and provides sufficient thermal stability even in harsh environments such as in-vehicle coil devices. It is providing the coil apparatus which can ensure the property, impact resistance, and vibration resistance.

  In order to solve the above-described problems, a coil device according to the present invention includes a core, a winding, an insulating resin outer package, and a terminal. The core is a rod-like body extending in one direction, and has a winding portion at an intermediate portion. The winding is wound around the winding portion. The insulating resin exterior body covers at least a part of the winding. The terminal is a portion for connecting the terminal of the winding, and is made of a single metal plate, one end is fixed to the terminal mounting portion of the core, and a bent portion is provided between the one end and the other end. And the bent portion is outside the insulating resin outer package. Furthermore, at least a part of the surface of the insulating resin outer package is roughened.

  As described above, since the insulating resin sheathing covers at least a part of the winding, the coil is protected by the insulating resin sheathing, and a coil device excellent in impact resistance, vibration resistance, etc. Can be realized. The insulating resin outer package is not limited to a part of the winding, but can cover all or further a part or all of the core. What is necessary is just to determine a coating aspect suitably by a use purpose and a use environment.

  The terminal connecting the end of the winding is made of a single metal plate, one end is fixed to the terminal mounting portion of the core, and there is a bent portion between the one end and the other end, and the bent portion is an insulating resin. Since it is outside the exterior body, when the coil device is mounted on a substrate or the like, the spring property by the bent portion can be secured and the impact and vibration can be absorbed. For this reason, the coil apparatus excellent in impact resistance, vibration resistance, etc. is realizable.

  As described above, since the winding is covered with the insulating resin sheathing body, the impact resistance and vibration resistance can be improved, but on the other hand, the heat generated in the winding due to the insulating resin sheathing body can be improved. Heat dissipation is hindered. Since the electrical resistance value of the winding has temperature dependence, the characteristics change unless heat dissipation is promoted. The core also shows changes in characteristics due to temperature.

  Therefore, as a means for solving this problem, in the present invention, at least a part of the surface of the insulating resin outer package is roughened. A representative example of roughening is what is called “texture processing”.

  As described above, when the surface of the insulating resin sheathing body is roughened, the surface area of the insulating resin sheathing body increases in accordance with the roughened surface area, roughening properties, and the like. For this reason, since the heat radiation area is expanded and heat radiation is promoted, the thermal stability of characteristics is improved. The roughening is ideally over the entire surface of the insulating resin outer package, but may be partial.

  The coil device according to the present invention can be used in many fields. As a specific application example, there may be an in-vehicle device antenna, an inductor, a choke coil, or the like.

  As described above, according to the present invention, heat dissipation is improved, the thermal stability of characteristics is improved, and sufficient thermal stability and shock resistance are provided even in harsh environments such as in-vehicle coil devices. It is possible to provide a coil device that can ensure the performance and vibration resistance.

  1 is an external perspective view showing an embodiment of a coil device according to the present invention. FIG. 2 is a perspective view showing an internal structure of the coil device shown in FIG. FIG. 3 is a front sectional view of the coil device shown in FIGS. 1 and 2. This coil device can be used for an antenna, a vehicle-mounted antenna, a transponder, a choke coil, an inductor of an electronic device, and the like.

  1 to 3, the coil device includes a core 10, a winding 4, terminals 51 and 52, and an insulating resin exterior body 7.

  The core 10 has terminal mounting portions 21 and 22 at opposite ends and a winding portion 1 at an intermediate portion. The core 10 is typically a ferrite core, and the material thereof is selected according to required characteristics. The ferrite core can be obtained by sintering a ferrite powder, machining a ferrite rod, or a combination of both.

  The winding portion 1 has an elongated shape extending long in the longitudinal direction X. In the illustrated embodiment, the winding part 1 has a square cross section. In addition, any cross-sectional shape such as another polygonal cross-section, a circular cross-section, or an elliptical cross-section can be adopted.

  Each of the terminal mounting portions 21 and 22 is provided at the both ends of the winding portion 1 in the longitudinal direction X and is provided in the same body as the winding portion 1, and has recesses 31 and 32 on the outer end surface in the longitudinal direction X. The terminal mounting portions 21 and 22 shown in the figure have a collar shape, and a cross section at a position where the concave portions 31 and 32 do not exist is a square cross section. It is preferable that the outer edge portions and the inner corner portions of the terminal mounting portions 21 and 22 are rounded or slightly chamfered.

  Each of the recesses 31 and 32 has a depth direction that coincides with the longitudinal direction X, extends in the width direction Y, and decreases in width toward the bottom. In the drawing, the concave portions 31 and 32 are substantially complete V-shaped in which both inclined surfaces intersect at the bottom and the depth direction coincides with the longitudinal direction X. In addition, the bottom part may be a flat surface or a circular surface. Moreover, although the recessed parts 31 and 32 are formed over the full width of the terminal attachment parts 21 and 22 in the figure, they may be shorter than the full width and closed at both ends.

  The winding 4 is wound around the winding portion 1 of the core 10. The number of windings 4, the wire diameter, and the like vary depending on the coil device to be obtained.

  The terminals 51 and 52 are made of a single bent metal plate. As the metal plate material constituting the terminals 51 and 52, a non-magnetic and springy material, for example, a phosphor bronze plate or a stainless steel plate such as SUS 304-CSP is suitable.

  Terminals 51 and 52 include a first bent portion F1 and a second bent portion F2. The first bent portion F1 generates attachment portions 511 and 521 that bend in a direction facing the outer end surface with a space from the attachment portions 511 and 521 guided in the direction away from the core 10 along the longitudinal direction X. The first bent portion F1 and the second bent portion F2 are outside the insulating resin outer package 7.

  The second bent portion F <b> 2 generates bottom portions 513 and 523 that are bent from the attachment portions 511 and 521 along the longitudinal direction X toward the core 10. The tips of the bottom portions 513 and 523, that is, the free ends are positioned outside the outer end surface of the core 10 when viewed in the longitudinal direction X. According to this arrangement, frequency-inductance characteristics and frequency-Q characteristics are improved.

  One end of each of the attachment portions 511 and 521 is fixed to the terminal attachment portions 21 and 22 of the core 10. Specifically, it is positioned inside the recesses 31 and 32 at a fixed position determined by the plate thickness. For this reason, the positions of the terminals 51 and 52 with respect to the core 10 are uniquely determined, and the fluctuation of the frequency-inductance characteristic and the fluctuation of the frequency-Q characteristic due to the positional fluctuation of the terminals 51 and 52 do not occur.

  The attachment portions 511 and 521 are further fixed inside the recesses 31 and 32 by adhesives 61 and 62 filled in the recesses 31 and 32. In this case, if a notch or the like is provided at one end inserted into the recesses 31 and 32, the adhesives 61 and 62 are filled in the notches, so that the strength of attaching the terminals 51 and 52 to the core 10 is improved. Winding terminals 41 and 42 are wound around the mounting portions 511 and 521 two to three times, and are preferably joined by Pb-free solder.

  The insulating resin exterior body 7 covers the entire core 10 and the winding 4. Furthermore, at least a part of the surface of the insulating resin outer package 7 is roughened. The insulating resin outer package 7 can be composed of an epoxy resin or the like.

  FIG. 4 is a cross-sectional view showing a use state of the coil device shown in FIGS. As shown in the drawing, the coil device is used by soldering 84 bottom portions 513 and 523 to a conductor pattern 82 provided on a circuit board 81 in a use state. The coil device is attached so that a gap is formed between the lower surface of the insulating exterior body 7 and the surface of the circuit board 81.

  Here, since the insulating resin sheathing body 7 covers the entire core 10 and the winding 4, the physically vulnerable core 10 and the entire winding 4 are protected by the insulating resin sheathing body 7. Thus, it is possible to realize a coil device excellent in impact resistance and vibration resistance.

  Further, the terminals 51 and 52 that connect the terminals of the winding 4 are made of a single metal plate, and one end is fixed to the terminal mounting portions 511 and 521 of the core 10. In addition, the first bent portion F1 and the second bent portion F2 are provided between the one end and the other end, and the first bent portion F1 and the second bent portion F2 are the insulating resin outer package 7. Outside.

  According to this structure, as shown in FIG. 4, when the coil device is mounted on the substrate 81, the spring property by the first bent portion F1 and the second bent portion F2 is secured, and the impact and Vibration can be absorbed. For this reason, the coil apparatus excellent in impact resistance, vibration resistance, etc. is realizable.

  As described above, since the entire core 10 and the winding 4 are covered with the insulating resin sheathing body 7, impact resistance, vibration resistance, and the like can be improved. , Heat release from the winding 4 is prevented. Since the electric resistance value of the winding 4 has temperature dependence, the characteristics change unless heat dissipation is promoted. The core 10 also shows a change in characteristics due to temperature.

  Therefore, as a means for solving this problem, in the present embodiment, at least a part of the surface of the insulating resin outer package 7 is roughened. A representative example of roughening is what is called “texture processing”.

  As described above, when the surface of the insulating resin sheathing body 7 is roughened, the surface area of the insulating resin sheathing body 7 increases according to the roughened surface area, roughening properties, and the like. For this reason, since the heat radiation area is substantially enlarged and heat radiation is promoted, the thermal stability of characteristics is improved.

  The roughening is ideally over the entire surface of the insulating resin outer package 7, but may be partial. As a surface roughening method, the surface (inner surface) of the mold used for forming the insulating resin outer package 7 is roughened to 3 to 9 μm by grain discharge processing, and the surface of the insulating resin outer package 7 is formed. Or a method of roughening the surface of the already formed insulating resin outer package 7 by sandblasting, chemical treatment, or the like.

  Furthermore, in the present embodiment, since the terminals 51 and 52 have the first bent portion F1 and the second bent portion F2, the springs formed by the first bent portion F1 and the second bent portion F2 are used. Depending on the nature, shock and vibration can be absorbed. For this reason, the coil apparatus excellent in impact resistance, vibration resistance, etc. is realizable.

  Moreover, in the present embodiment, the intermediate portions 512 and 522 have holes 514 and 524 in the plane. The holes 514 and 524 are arcuate at both inner edges facing each other in at least one direction. Next, this point will be described.

  The intermediate portions 512 and 522 are portions facing the end surface of the core 10, and have a relationship in which the plate surface is orthogonal or intersects with the magnetic flux caused by the current flowing through the winding 4. For this reason, it becomes an obstruction part which prevents the smooth flow of magnetic flux, and may deteriorate a frequency-inductance characteristic and a frequency-Q characteristic. Therefore, in the present embodiment, holes 514 and 524 are provided in the plane of the intermediate portions 512 and 522.

  Due to the presence of the holes 514 and 524 described above, the cross-sectional area of the intermediate portions 512 and 522 is smaller than the cross-sectional areas of the mounting portions 511 and 521 and the bottom portions 513 and 523, so that the obstacle to the flow of magnetic flux is reduced, and the frequency -Degradation of inductance characteristics and frequency-Q characteristics is suppressed.

  As described above, by providing the holes 514 and 524 in the intermediate portions 512 and 522, the mechanical strength of the intermediate portions 512 and 522 is lowered. The decrease in mechanical strength must be minimized. Otherwise, the impact resistance and vibration resistance required in applications where the usage environment is severe, such as an in-vehicle coil device, cannot be secured.

  As this means, in the present embodiment, the holes 514 and 524 have a shape in which both inner edges facing each other in at least one direction are arcuate. The holes 514 and 524 are not limited to circular holes, but may be oblong holes or elliptical holes.

  According to the above-described hole shape, unlike a square hole having a sharp inner angle, for example, sufficient mechanical strength is ensured, and impact resistance and resistance required in harsh use environments such as in-vehicle coil devices. The vibration property can be sufficiently satisfied. At first glance, it seems to be a simple technical process that only turns a square hole into a circular hole, but it is a very effective means of exerting the maximum effect in a limited structure.

  In addition, the holes 514 and 524 have the second bent portion F1 and the distance Z11 from the second bent portion F2 to the hole edge when viewed in the direction of the height Z, the first bent portion F1, In addition, it is preferable that the positions that are larger than the distance Z12 from the second bent portion F2 to the hole edge, that is, the holes 514 and 524 are arranged so as to be biased toward the mounting portions 511 and 521.

  FIG. 5 is a sectional view showing another embodiment of the coil device according to the present invention. In the figure, parts corresponding to those shown in FIGS. 1 to 3 are denoted by the same reference numerals, and redundant description is omitted. In this embodiment, the core 10 has a partition portion 23 at an intermediate portion, and is provided with windings 4 on both sides thereof. That is, the winding part 1 is divided into a plurality. The winding 4 is wound continuously in the same direction in a plurality of winding portions 1. The insulating resin outer package 7 has a roughened almost entire surface. In the case of this embodiment, the same operational effects as the embodiment shown in FIGS.

  Although the contents of the present invention have been specifically described with reference to the preferred embodiments, various modifications can be made by those skilled in the art based on the basic technical idea and teachings of the present invention. It is self-explanatory.

1 is an external perspective view showing an embodiment of a coil device according to the present invention. FIG. 2 is a perspective view illustrating the internal structure of the coil device illustrated in FIG. 1 with an insulating resin outer package omitted. It is front sectional drawing of the coil apparatus shown in FIG.1 and FIG.2. It is a figure which shows the use condition of the coil apparatus shown in FIGS. It is sectional drawing which shows another embodiment about the coil apparatus which concerns on this invention.

Explanation of symbols

1 Winding part 21, 22 Terminal mounting part 31, 32 Recessed part
4 Windings 51, 52 terminals
7 Insulating resin exterior

Claims (2)

A coil device including a core, a winding, an insulating resin outer package, and a terminal,
The core is a rod-shaped body extending in one direction, and has a winding part in the middle part,
The winding is wound around the winding portion,
The insulating resin exterior body covers at least a part of the winding,
The terminal is a part for connecting the terminal of the winding, is made of a single metal plate, one end is fixed to the terminal mounting part of the core, and a bent part is provided between the one end and the other end. And the bent portion is outside the insulating resin outer package,
Furthermore, the insulating resin outer package has a roughened at least part of the surface,
Coil device. The coil device according to claim 1, wherein the coil device is an antenna, a choke coil, or an inductor.

Images