JP2008181947A - Coil component for antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil component for an antenna, capable of easily and surely adjusting the resonant frequency of a serial resonant circuit and stable propagation of magnetic field. <P>SOLUTION: The coil component 10 for an antenna includes: a magnetic core 20; a base 30 made of a non-magnetic material and having the magnetic core to be attached thereon; a coil 22 wound around the magnetic core; a chip capacitor 26 connected in series to the coil; and a movable core 50 slidably attached on the base in the winding axis direction of the coil and varying the inductance of the coil by changing the relative position with the magnetic core. In the coil component 10, an engaging portion 52 with a position adjusting tool is formed on the moving core so as to be exposed from a moving core housing recess 32 provided on the base 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antenna coil component in which a resonance circuit is configured by a coil wound around a magnetic core and a capacitor connected in series with the coil.

  With regard to this type of technology, for example, many antenna coil parts are used in a keyless entry system that can lock or unlock a door of a car or a house without directly touching it by transmitting and receiving signal radio waves. .

When an alternating current corresponding to the resonance frequency of a series resonance circuit composed of a coil and a capacitor is applied to the transmitting antenna, a magnetic field is generated and can be propagated into the atmosphere.
In the keyless entry system, when a user who has a remote control device with a built-in transmission / reception antenna enters or exits the magnetic field propagation range generated by the transmitting antenna installed on the door side, The remote control device is activated to lock or unlock the door.

By making the resonance frequency (f ₀ ) of the series resonance circuit represented by the following formula (1) coincide with the frequency of the alternating current applied to the series resonance circuit, the resonance current flowing through the coil becomes large. It is known that the resonance current decreases dramatically due to the deviation.
Resonance frequency: f ₀ = 1 / 2π√ (L × C) (1)

Therefore, in order to operate the keyless entry system stably, the inductance (L) of the coil constituting the transmitting antenna and the electrostatic capacity (C) of the capacitor are desired so as to coincide with the operating frequency set in advance by specifications. It is desired that the resonance frequency (f ₀ ) is adjusted to the value of, and the frequency of the alternating current is adjusted as desired by the power supply circuit.

However, the inductance (L) of the coil constituting the transmitting antenna and the capacitance (C) of the capacitor inevitably vary from product to product, and in particular, the capacitance (C) of the capacitor is a wiring type. Therefore, it is difficult to realize a desired resonance frequency (f ₀ ) for each product. As a result, the resonance current applied to the antenna coil varies from product to product and the electromotive force induced in the antenna is reduced, so that the magnetic field propagation range becomes unstable, the transmission / reception sensitivity decreases, and the transmission antenna and remote Problems such as a short communication distance with the control device have occurred.

On the other hand, in the transmitting antenna described in Patent Document 1 below, an annular first coil and a second coil in which a winding is wound around a small-diameter bobbin accommodated therein are provided, and the core of each coil is provided. These ferrite cores can be screwed together (see Patent Document 1: FIG. 1). Thus, the resonance frequency (f ₀ ) can be adjusted by changing the magnetic coupling degree between the cores by increasing / decreasing the screwing depth of the ferrite core and making the coil inductance variable. Further, it is described that the relationship between the screwing depth and the resonance frequency can be reversed by changing the material of the small-diameter bobbin of the second coil from ferrite to nonmagnetic material.

Japanese Patent No. 3735104

  However, the transmitting antenna described in the above-mentioned patent document adjusts the screwing depth with respect to the annular first coil by rotating a jig tool such as a flat-blade screwdriver applied to a groove formed in a screw core of a small-diameter bobbin. Therefore, (1) In particular, in the case of a screw core made of a sintered body of ferrite, the brittleness is low, so there is a high possibility that the screw core will be damaged due to torque during rotation adjustment with a jig tool. It is difficult and costly to form the screw core. (3) If the operator mistakenly tries to screw the screw core diagonally, the position adjustment cannot be performed well and the screw core may be damaged. (4) If the screw core position adjustment amount is large, the number of rotations of the screw will increase and a lot of work time will be required. (5) The screw core will be deeper than the screw core itself. (6) The problem is that the number of manufacturing processes is high and the cost is high because it is necessary to apply a lubricant to the screw thread in order to improve the screw-in of the screw core. There is.

  The present invention has been made to solve the above-described problem, that is, to provide a coil component for an antenna in which the resonance frequency of a series resonance circuit can be easily and reliably adjusted and stable magnetic field propagation is possible. For the purpose.

  The present invention is an antenna coil component that adjusts the inductance of a coil by changing the relative position of a magnetic core and a moving core, and thereby can increase or decrease the resonance frequency of a series resonance circuit, and The moving core is arranged to be slidable in the winding axis direction of the coil with respect to the base to which the magnetic core is attached.

That is, the present invention
(1) A magnetic core, a base made of a non-magnetic material to which the magnetic core is attached, a coil wound around the magnetic core, a capacitor connected in series to the coil, and the base A coil part for an antenna comprising: a moving core that is slidably arranged in a winding axis direction of the coil and changes the inductance of the coil by changing a relative position with the magnetic core;
(2) The moving core is slidably fitted to the base, and the moving core can be accessed by a position adjusting tool from at least one direction crossing the sliding direction of the moving core. In the above (1), an opening is formed, and the movable core fitted into the opening is formed with an engaging portion that is exposed from the opening and is engaged with a position adjusting jig. Coil components for antennas as described in);
(3) The antenna as described in (1) or (2) above, wherein the base and the moving core are formed with guide rails or sliding grooves that are concavo-convexly engaged with each other, extending in the sliding direction. Coil parts;
Is a summary.

In (1) above, the movable core is slidable in the direction of the winding axis of the coil, in addition to the case of sliding in parallel with the direction, as long as the sliding direction has a component in the winding axis direction. It also includes the case of having a component in the direction.
Further, in (2) above, the fact that the engaging portion of the moving core is exposed from the opening of the base means that when the position adjustment is performed by sliding the moving core with respect to the base with the position adjusting tool. It is sufficient that the engaging portion is exposed from the opening, and after the position adjustment, the engaging portion of the moving core may be covered with a base or another member.
In (3) above, the guide rail or the sliding groove is formed in the base and the moving core. (I) The case where the convex guide rail is formed in the base and the concave sliding groove is formed in the moving core; (Ii) This means both modes when a concave sliding groove is formed on the base and a convex guide rail is formed on the moving core.

Further, the present invention further includes a specific embodiment as follows:
(4) The moving core is made of a magnetic material, and the degree of magnetic coupling changes according to the change in the relative position between the moving core and the magnetic core, as described in any one of (1) to (3) above Coil components for antennas;
(5) The antenna according to any one of (1) to (4), wherein the moving core is slidable outside the magnetic core and parallel to the winding axis direction of the coil. Coil parts;
The above-described problems can be solved and the object of the present invention can be achieved.

According to the present invention, the resonance frequency (f ₀ ) of the series resonance circuit composed of the coil and the capacitor can be increased or decreased by sliding the moving core in the coil winding axis direction to increase or decrease the inductance of the coil. Therefore, a desired resonance current is applied in accordance with the frequency of the applied alternating current, thereby enabling stable magnetic field propagation. In particular, when the moving core is made of a magnetic material together with the magnetic core, the degree of increase or decrease in the inductance of the coil can be increased by sliding the moving core to change the degree of magnetic coupling with the magnetic core. it can.
At this time, since the moving core is slidably arranged with respect to the base, even when the moving core is formed of a material having low brittleness such as ferrite, it is not necessary to provide a spiral screw thread on the moving core. It is excellent in workability, and there is no possibility that the moving core is damaged due to excessive torque being applied during position adjustment. In addition, unlike the conventional transmission antenna, the ferrite cores are screwed together, and the method of the present invention in which the moving core is slid with respect to the base allows the position to be determined regardless of the length of the moving core. The stroke of the adjustment amount can be increased, and even when the stroke is large, it can be easily moved to adjust the position.

  In the antenna coil component according to the present invention, as a more specific aspect, the base is slidably fitted to the base, and from at least one direction crossing the sliding direction of the mobile core, An opening that can be accessed by a position adjusting tool may be formed on the fitted moving core, and the moving core fitted to the opening is exposed from the opening to be positioned. You may form an engaging part with the adjustment tool. With this configuration, after setting up the magnetic core wound around the coil, the moving core, and the capacitor attached to the base, the position adjustment of the moving core with the position adjusting jig can be easily and reliably performed from the outside through the opening. Can be done.

  Moreover, in the coil component for antenna according to the present invention, as a more specific aspect, a guide rail or a sliding groove that is concavo-convexly fitted to each other may be formed on the base and the moving core so as to extend in the sliding direction. . With such a configuration, the moving core slides with respect to the base in a state where the guide rail and the sliding groove are fitted to each other. Therefore, when the position of the moving core is adjusted, this is inclined obliquely. The antenna can be moved smoothly without rotating, and the resonance frequency of the antenna can be adjusted easily and with high accuracy.

  Hereinafter, the best mode for carrying out the present invention will be described more specifically. FIG. 1 is a perspective view of an antenna coil component 10 according to the present embodiment (hereinafter sometimes abbreviated as a coil component 10), and FIG. 2 is an exploded perspective view thereof. 3 is a plan view of the upper surface side of the coil component 10, and FIG. 4 is a plan view of the lower surface side of the coil component 10.

  The coil component 10 of the present embodiment can be suitably used for a transmission antenna of a keyless entry system that is attached to the door side of an automobile or a house.

  The coil component 10 of the present invention has a relative position between the magnetic core 20 around which the coil 22 is wound, a chip capacitor 26 connected in series to the coil 22, a base 30 to which these are attached, and the magnetic core 20. A moving core 50 for adjusting the inductance of the coil 22 by being changed is provided. In the coil component 10 of the present invention, the moving core 50 is mounted on the base 30 so as to be slidable in the winding axis direction of the coil 22.

As understood from the above equation (1), since there is a negative correlation between the resonant frequency of the series resonant circuit inductance (f ₀₎ and the coil 22 (L), the capacitance of the capacitor (chip capacitor 26) (C: Hereinafter, the influence of parasitic capacitance such as wiring of the coil component 10 is ignored.) When the inductance is constant, the resonance frequency (f ₀ ) is increased by increasing the inductance (L) of the coil 22. The resonance frequency (f ₀ ) can be increased by decreasing the size and decreasing the inductance (L) of the coil 22.

Here, in the present invention, the inductance of the coil 22 is increased or decreased by changing the relative position between the magnetic core 20 and the moving core 50.
Depending on whether the moving core 50 is a magnetic material or a non-magnetic material, the influence of the change in the relative position between the magnetic core 20 and the moving core 50 on the inductance of the coil 22 varies as follows.

(A) When the moving core 50 is made of a magnetic material such as ferrite, the degree of magnetic coupling between the moving core 50 and the magnetic core 20 is improved and the inductance of the coil 22 is increased. Conversely, when the moving core 50 is moved away from the magnetic core 20, the degree of magnetic coupling between the two decreases and the inductance of the coil 22 decreases.
(B) When the moving core 50 is made of a nonmagnetic material having a relative permeability lower than that of air (relative permeability is 1.000004) such as copper or silver, the coil 22 is brought into close contact with the moving core 50 and the magnetic core 20. When the moving core 50 is moved away from the magnetic core 20, the inductance of the coil 22 increases.
The generation mechanism itself of (a) and (b) will be apparent to those skilled in the art.

  Among these, in the present invention, by adopting the above (a) in which the moving core 50 is a magnetic material, the variation range of the inductance of the coil 22 is increased, and thereby the adjustment range of the resonance frequency of the coil component 10 is increased. This is preferable.

  As for the direction in which the relative position between the magnetic core 20 and the moving core 50 is changed, both the above (a) and (b) are parallel to the direction in which the magnetic core 20 extends, that is, the winding axis direction of the coil 22. The moving sensitivity of the coil 22 is maximized by moving the moving core 50 to the maximum. In other words, when the adjustment amount of the resonance frequency of the coil component 10 is ensured to be constant, the position adjustment amount of the moving core 50 can be minimized by moving the moving core 50 in parallel with the winding axis direction of the coil 22. Therefore, the dimension of the coil component 10 in the winding axis direction can be kept small, and the whole can be downsized.

However, in the present invention, it is not excluded that the moving core 50 moves relative to the magnetic core 20 in the direction intersecting with the winding axis direction of the coil 22. As long as it has a moving component that slides in parallel, it may have some moving component in the direction crossing it.
That is, for example, when the moving core 50 is made of a magnetic material, the moving core 50 and the magnetic core 20 are magnetically coupled by moving the moving core 50 relative to the magnetic core 20 in parallel with the winding axis direction of the coil 22. It can be said that it is most preferable because the degree of sensitivity can be increased / decreased with the highest sensitivity, and the inductance of the coil 22 can be greatly increased / decreased, and the width dimension of the coil component 10 does not need to be expanded. However, in addition to this, the magnetic core 20 and the moving core 50 can be moved in and out of the magnetic core 20 so as to cross the magnetic core 20 in the width direction with respect to the magnetic flux extending in the radial direction from the magnetic core 20. Since the degree of magnetic coupling can be changed, the inductance of the coil 22 may be increased or decreased by sliding the moving core 50 so as to include such a width direction component.

In addition to (a) a mode in which the moving core 50 relatively moves so as to approach or move away from the outside of the magnetic core 20, (a) a concave groove is provided in the magnetic core 20, for example. The moving core 50 may be relatively movable from the inside to the outside of the magnetic core 20.
In the former case (a), when the moving core 50 is moved relative to the magnetic core 20 and a desired resonance frequency is obtained by the coil component 10, the accessibility by a position adjusting tool or the like is improved. Therefore, it is preferable. In the case of the latter (A), there is an advantage that the phenomenon that the inductance of the coil 22 increases or decreases based on the above (a) and (b) occurs more remarkably.

  The coil component 10 of the present embodiment employs the above (a) and (a) as shown by double-sided arrows in FIG. 1, the moving core 50 is made of a magnetic material such as ferrite, and the outside of the magnetic core 20. In FIG. 3, the magnetic core 20 is configured to be relatively movable so as to approach or move away from the magnetic core 20 in parallel with the length direction of the magnetic core 20 (see FIG. 3), that is, in parallel with the winding axis direction of the coil 22.

  When the coil component 10 of the present invention is used for, for example, a transmission antenna of a keyless entry system, the magnetic core 20 is generally formed of a magnetic material such as ferrite in the shape of a rod, and from the conductor along the length direction thereof. A coil 22 is spirally wound.

  The magnetic core 20 around which the coil 22 is wound is attached to the base 30. The base 30 is preferably made of a nonmagnetic material so that a closed loop of a magnetic circuit that inhibits propagation of magnetic flux generated by the coil 22 is not formed. The base 30 is preferably made of a non-conductive material so that eddy currents caused by the magnetic flux generated by the coil 22 are not generated. Further, from the viewpoint of moldability, the base 30 may be molded from a resin material.

  The base 30 according to the present embodiment is roughly classified into a moving core housing recess 32 in which the moving core 50 is slidably mounted and one end in the length direction of the magnetic core 20 (hereinafter, the base 30 side of the magnetic core 20). An annular insertion portion 34 for fitting and fixing, and a stage-shaped chip capacitor mounting portion 36 on which a plurality of metal terminals protrude and on which the chip capacitor 26 is mounted. It consists of.

  As shown in FIG. 2, in the magnetic core 20, the tip around which the coil 22 is not wound is inserted and fixed to the insertion portion 34. The magnetic core 20 whose tip is inserted into the insertion portion 34 may be fixed by an adhesive, or the inner diameter of the insertion portion 34 is formed slightly smaller than the outer diameter of the magnetic core 20 so as to be magnetic. The body core 20 may be press-fitted and fixed to the insertion part 34.

  The lead wires 24 a and 24 b of the coil 22 wound around the magnetic core 20 are wound around a metal terminal provided on the base 30 and fixed. Specifically, in the coil component 10 of the present embodiment, one lead wire 24 a of the coil 22 is wound around a binding terminal 44 protruding in the width direction from the base 30, and the other lead wire 24 b is wound on the base 30. It is wound around the harness terminal 42b protruding to the front side. The harness terminal 42b is an interface to which an external electronic device such as a control circuit and a power supply circuit of the coil component 10 serving as an antenna is connected together with the paired harness terminal 42a.

  As shown in FIG. 4, lead-out grooves 46 a and 46 b reaching the binding terminal 44 and the harness terminal 42 b are provided on the back surface side of the base 30, and the lead-out wires 24 a and 24 b are from the outer envelope region of the base 30. These can be pulled out from the coil 22 without being exposed to the outside, and can be joined and fixed to the binding terminal 44 and the harness terminal 42b.

  2, the chip capacitor 26 is mounted between the land 441 of the binding terminal 44 and the land 421 of the harness terminal 42a, and the coil 22 and the chip capacitor 26 are connected in series. The coil component 10 constitutes a series resonant circuit.

  The chip capacitor mounting portion 36 is provided with a mounting hole 37 in which the lands 421 and 441 are exposed. The chip capacitor 26 can be fitted into the mounting hole 37 and joined to the lands 421 and 441 by means such as soldering. . After the chip capacitor 26 is bonded, the mounting hole 37 may be filled with a resin material to mechanically protect the chip capacitor 26 and the lands 421 and 441.

FIG. 5 is an enlarged view showing the tip side of the base 30 and the coil 22 in the top plan view of the coil component 10 shown in FIG. However, the path of the alternating current applied to the coil 22 is schematically represented by a solid line with an arrow.
The binding terminal 44 to which one lead wire 24a of the coil 22 is connected is electrically connected to the harness terminal 42a through the chip capacitor 26, and is electrically connected to an external electronic device (not shown). Further, an external electronic device is connected to the harness terminal 42b and is electrically connected to the coil 22 through the lead wire 24b, whereby an alternating current is applied to the series resonance circuit of the coil component 10.

The coil component 10 according to the present invention is obtained by moving the moving core 50 relative to the magnetic core 20 from the state in which the magnetic core 20, the coil 22 and the chip capacitor 26 are all fixed to the base 30. The inductance (L) of 22 can be finely adjusted, and the desired resonance frequency (f ₀ ) is realized in the coil component 10 by absorbing the variation of the capacitance (C) of the chip capacitor 26 for each product. . In particular, the present invention allows the moving core 50 to be slid with respect to the base 30 so that the moving core 50 can be suitably adjusted from the state in which the magnetic core 20, the coil 22 and the chip capacitor 26 are mounted on the base 30. It is characterized by being mounted movably.

  That is, unlike the conventional transmitting antenna in which the magnetic core and the moving core are screwed together to increase or decrease the screwing depth, the moving core is separated from the magnetic core 20 and separated from the base 30 in the present invention. By making it slidable, it is not necessary to provide a screw thread on the core, and the position of the moving core can be easily adjusted.

In the present embodiment, as an aspect in which the moving core 50 is slidably disposed on the base 30, a concave groove extending in the winding axis direction of the coil 22 is provided in the base 30 as shown in FIG. And the movable core 50 is slidably fitted.
That is, the width dimension of the moving core housing recess 32 is substantially the same as the width dimension of the moving core 50 (see FIG. 3). The length dimension of the moving core housing recess 32 is formed to be equal to or larger than the position adjustment width (stroke) of the moving core 50, and preferably the length of the moving core 50 itself plus the length exceeding the stroke. That is, in a state where the moving core 50 is moved away from the magnetic core 20 and the position is adjusted, a part of the moving core 50 protrudes from the moving core housing recess 32 in the sliding direction, or the moving core 50 is still in the moving core housing recess. 32 may be completely accommodated.

  The outer shape of the moving core 50 is not particularly limited, and may be a prismatic shape as in the present embodiment, or may be a columnar shape, a spherical shape, or the like. Since it is necessary to fix it to the prism, it can be said that the prismatic shape is preferable because the posture is easily stabilized.

When the moving core 50 is made of a magnetic material, the length of the moving core 50 is long enough to sufficiently increase or decrease the degree of magnetic coupling with the magnetic core 20 to obtain a large adjustment range of the resonance frequency, and the coil component 10 as a whole. The length can be selected as appropriate within the range satisfying the constraints of the length dimension. The width dimension of the moving core 50 can be formed narrower than the magnetic core 20 as shown in the figure.
In the coil component 10 of the present embodiment in which the moving core 50 is moved relative to the magnetic core 20 in parallel with the winding axis direction of the coil 22, the moving core 50 has a width dimension in order to increase the sensitivity of increase / decrease in magnetic coupling. The whole or at least part of the moving core 50 is preferably attached to a position within the width of the magnetic core 20, and particularly, the moving core 50 is preferably attached to the base 30 to be within the width of the magnetic core 20 as illustrated. .

  FIG. 6 is a front view of the coil component 10 as viewed from the moving core housing recess 32 side to which the moving core 50 is attached. As shown in FIGS. 2 and 6, concave grooves extending in the sliding direction are formed as sliding grooves 54 a and 54 b on both side surfaces facing the width direction of the moving core 50, respectively. On the side, guide rails 38 a and 38 b that are concavo-convexly fitted to the sliding grooves 54 a and 54 b are formed extending in the sliding direction of the moving core 50.

The guide rails 38a and 38b and the sliding grooves 54a and 54b slide the moving core 50 while maintaining the relative angle with the magnetic core 20 so that the moving core 50 does not tilt and engage with the base 30 when sliding. It has a guide function to assist.
As long as the guide rail and the sliding groove are provided between the base 30 and the moving core 50 so as to extend in the sliding direction of the moving core 50, the specific formation positions are not particularly limited. As shown in the figure, in addition to the aspect provided on the inner surface of the moving core housing recess 32 in the base 30, for example, the base 30 is formed in a flat plate shape and a guide rail is erected on the upper surface thereof. A sliding groove may be formed on the bottom surface.
However, as in this embodiment, the guide rails 38a and 38b are erected in the direction intersecting with the opening direction of the moving core housing recess 32 (upward in FIG. 6) (left and right direction in FIG. 6) so The guide rail and the sliding groove that have the function of retaining the moving core 50 prevent the moving core 50 from falling out of the moving core housing recess 32 in the opening direction.

  From the viewpoint of obtaining the same function, the guide rails 38 a and 38 b are formed so as to protrude from the base 30, and the guide rails 38 a and 38 b are erected on the movable core 50 side, and the base 30 side is provided. The sliding grooves 54a and 54b may be formed by digging.

  In the coil component 10 of the present embodiment in which the moving core 50 is retained by the guide rails 38a and 38b and the sliding grooves 54a and 54b, the coil 22 is arranged from the distal end side (lower side in FIG. 3) of the moving core housing recess 32. The moving core 50 can be attached to the base 30 by pushing the moving core 50 in the winding axis direction.

  The projecting height of the guide rails 38a and 38b and the digging depth of the sliding grooves 54a and 54b can typically take the following two ways. That is, (a) the inner surface of the moving core housing recess 32 and the side surface of the moving core 50 are in contact with each other, and the guide rails 38a, 38b and the sliding grooves 54a, 54b are loosely fitted; In this embodiment, the inner side surface of the storage recess 32 and the side surface of the movable core 50 are not in contact with each other, and the guide rails 38a and 38b and the sliding grooves 54a and 54b are in contact with each other. Although the coil component 10 of the present invention can be employed in any of the above-described aspects (a) and (ii), it is difficult in terms of processing accuracy to bring the moving core housing recess 32 and the moving core 50 into good contact with each other. Therefore, the latter is preferable from the viewpoint of reducing the contact area between the base 30 and the moving core 50 and reducing the sliding friction between them.

  On the bottom surface of the moving core housing recess 32, one or a plurality of ridges 39 extend in the sliding direction of the moving core 50 and protrude in line contact with the bottom surface of the moving core 50 to reduce sliding friction. Is formed.

  The moving core storage recess 32 of the present embodiment is formed as an opening that opens to the upper surface side of the base 30. As a result, the moving core 50 attached to the base 30 can be accessed from above the base 30. On the other hand, the moving core 50 of the present embodiment is formed in a prismatic shape as a whole, and a concave groove extending in a direction crossing the sliding direction as shown in FIG. It is formed as an engaging portion 52 for the tool. Thereby, for example, a general-purpose tool such as a flat-blade screwdriver or a dedicated tool can be hooked on the engaging portion 52, and the moving core 50 can be slid in the moving core housing recess 32. Note that the shape of the engaging portion 52 is not limited to the illustrated groove, and may be a groove having a different shape or a protrusion as long as it can be engaged with the position adjusting jig.

  In this way, the engaging portion 52 is a position exposed from the opening of the moving core housing recess 32 (in this embodiment, the upper surface side of the base 30) and in a direction crossing the sliding direction of the moving core 50. By providing, the accessibility by the position adjusting tool is not lost regardless of the position of the moving core 50. That is, when the engaging part 52 is formed in the front-rear direction of the sliding direction of the moving core 50, the innermost part of the moving core housing recess 32 (the uppermost position in FIG. 3) to bring the moving core 50 closest to the magnetic core 20. Then, the movable core 50 may be difficult to be pulled out and adjusted in position, and the engaging portion 52 is formed so as to be exposed in the crossing direction of the sliding direction. Regardless of the moving position, it can be accessed with a position adjusting tool.

The position adjustment of the moving core 50 may be performed in a state where the measuring device for the resonance frequency of the coil component 10 is connected to the harness terminals 42a and 42b. That is, the resonance frequency of the coil component 10 is measured while gradually moving the moving core 50 closer to or away from the magnetic core 20 with a position adjusting jig, and the moving core 50 is moved to a position where a desired resonance frequency (f ₀ ) is obtained. It may be fixed to the base 30.

  The moving core 50 and the base 30 may be fixed by impregnating an adhesive between the moving core housing recess 32 and the moving core 50. However, the guide rails 38a and 38b and the sliding grooves 54a and 54b are connected to each other. While being formed in the form (ii), it is possible to adopt a press-fitting method in which the two movable cores 50 are fixedly held in the movable core housing recesses 32 as they are tightly fitted to each other so as to come into pressure contact with each other. When the moving core 50 is made of a sintered body of low brittleness, the moving core 50 is formed even when the moving core 50 is press-fitted and fixed in the moving core housing recess 32 by molding the base 30 with an elastic resin material. Is suitable without being damaged.

As another embodiment of the present invention, the opening direction of the opening accessed by the position adjusting tool may be directed to the side (width direction side) instead of the upper surface side of the base 30 as illustrated. That is, the movable core housing recess 32 extending in the winding axis direction of the coil 22 may be formed to open toward the side (outside in the width direction) of the base 30, and the movable core 50 may be slidably attached thereto. In addition, openings may be formed on both the upper surface side and the lateral side of the base 30 so that the movable core 50 can be accessed from two directions.
In addition, a tunnel-shaped concave hole extending in the winding axis direction of the coil 22 is formed in the base 30, and the moving core 50 is slidably inserted into the tunnel, while the side of the concave hole is opened from the side. Various modes can be adopted, such as a method in which an adjustment window is formed as a part and accessed by a position adjusting tool.

In the present invention, the opening provided in the base 30 may be constituted by a guide plate that sandwiches the moving core 50 instead of the moving core housing recess 32. That is, for example, by opening a pair of opposing guide plates on the base 30 and sandwiching the movable core 50 therebetween, an opening can be formed in the direction in which the guide plates stand.
In this case, the guide rails 38a and 38b or the sliding grooves 54a and 54b may be formed on the inner surfaces of the opposing guide plates, respectively.

  In the present invention, in addition to the above-described embodiment in which the magnetic core 20 is fixedly attached to the insertion portion 34 of the base 30, the insertion depth of the magnetic core 20 relative to the insertion portion 34 may be variable. That is, as described above, the coil component 10 of the present invention can change the relative position with the magnetic core 20 by slidably attaching the moving core 50 to the base 30 and adjust the inductance of the coil 22. However, similarly, the magnetic core 20 may also be provided so as to be slidable with respect to the base 30 to increase the adjustment range of the relative movement with the moving core 50. However, the lead wires 24a and 24b of the coil 22 wound around the magnetic core 20 are wound around the binding terminal 44 and the harness terminals 42a and 42b of the base 30 as shown in FIG. Since the play on the wire is small and the allowable sliding amount of the magnetic core 20 with respect to the base 30 is considered to be small, the change in the relative position between the magnetic core 20 and the moving core 50 is the moving core 50 with respect to the base 30. The effect of sliding will be the main one.

1 is a perspective view of a coil component 10 according to an embodiment of the present invention. 1 is an exploded perspective view of a coil component 10. 3 is a plan view of the upper surface side of the coil component 10. FIG. 3 is a plan view of the lower surface side of the coil component 10. FIG. It is an enlarged view which shows the front end side of the base 30 and the coil 22 among the upper surface side top views of the coil component 10 shown in FIG. It is the front view of the coil component 10 seen from the moving core accommodation recessed part 32 side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Antenna coil components 20 Magnetic core 22 Coils 24a, 24b Lead wire 26 Chip capacitor 30 Base 32 Moving core accommodation recessed part (opening part)
34 Insertion part 36 Chip capacitor mounting part 38a, 38b Guide rail 42a, 42b Harness terminal 44 Tying terminal 46a, 46b Leading groove 50 Moving core 52 Engaging part 54a, 54b Sliding groove

Claims (3)

A magnetic core;
A base made of a non-magnetic material to which the magnetic core is attached;
A coil wound around the magnetic core;
A capacitor connected in series to the coil;
A coil component for an antenna, comprising: a moving core that is slidably arranged in the winding axis direction of the coil with respect to the base and changes the inductance of the coil by changing a relative position with the magnetic core. The moving core is slidably fitted to the base, and the fitting moving core can be accessed by a position adjusting tool from at least one direction crossing the sliding direction of the moving core. An opening is formed,
2. The antenna coil component according to claim 1, wherein the moving core fitted in the opening is formed with an engaging portion that is exposed from the opening and engages with a position adjusting jig. 3. .   3. The antenna coil component according to claim 1, wherein a guide rail or a sliding groove that is unevenly fitted to each other is formed on the base and the moving core so as to extend in the sliding direction.

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