JPH0297005A - variable inductance - Google Patents

Abstract

PURPOSE:To obtain an improved highly reliable high frequency coil capable of stable and precision frequency setting and facilitating adjustment operation by providing a support member having a threaded hole coaxial with an air-core coil and rotatably mounting an adjusting screw in the threaded hole. CONSTITUTION:A support member 1 having a threaded hole 3 is provided coaxially with an air-core coil 5 and an adjusting screw 2 is rotatably mounted in the threaded hole 3. For example, by using a shielding case 1 for the support member for the adjusting screw 2, the air-core coil 5 is designed beforehand to be disposed in the vicinity of the shielding case 1. The air-core coil 5 is fixed to a circuit board 4 at a soldering part 6, and further, copper foil 7 on the rear surface of the circuit board 4 and the shielding case 1 are fixed to each other by soldering 8. Then, the threaded hole 3 is provided at the point where the extension of the central axis of the air-core coil 5 intersects the shielding case 1, and the electrically conductive adjusting screw 2 is inserted into the threaded hole 3 and the spacing between the front end of the screw and the nearest winding end of the air-core coil 5 is changed from the outside by rotating the adjusting screw 2 utilizing a screwdriver.

Description

Translated fromJapanese

【発明の詳細な説明】［産業上の利用分野］この発明は可変インダクタンスに関し、更に詳しくは、
短波帯、超短波、極超短波帯の発振、同調、及び共振回
路に用いられる高周波用可変インダクタンスに関する。[Detailed Description of the Invention] [Industrial Application Field] This invention relates to variable inductance, and more specifically,
This invention relates to variable inductance for high frequencies used in oscillation, tuning, and resonant circuits in the shortwave band, very short wave band, and very short wave band.

［従来の技術］一般に短波帯以下の高周波用のコイルにおいては、鉄芯
やフェライトコア等、空芯コイルの場合に比して透磁率
の高い物質を設けることにより、コイル内部の磁束密度
を増加させることで小型のコイルでも十分なインダクタ
ンスを得ることができる。この場合、インダクタンスの
調整においてはコイル内のコアの位置を変更することに
より、磁束密度が変化するため、容易に調整できる。[Prior art] Generally, in coils for high frequencies below the shortwave band, the magnetic flux density inside the coil is increased by providing a material with higher magnetic permeability, such as an iron core or ferrite core, than in the case of an air-core coil. By doing so, sufficient inductance can be obtained even with a small coil. In this case, when adjusting the inductance, the magnetic flux density changes by changing the position of the core within the coil, so the inductance can be easily adjusted.

短波帯以上になると鉄芯なとのバルク材においては渦電
流による反磁界、フェライトにおいては磁気余効の効果
のため、磁束密度は必ずしも増加しない、そのため１０
０ＭＨｚ以上の周波数では専ら空芯コイルが用いられ、
比較的少ない巻数でも十分なインダクタンスが得られる
。Above the short wave band, the magnetic flux density does not necessarily increase due to the demagnetizing field caused by eddy current in bulk materials such as iron cores, and the magnetic aftereffect effect in ferrite.
At frequencies above 0MHz, air-core coils are used exclusively.
Sufficient inductance can be obtained even with a relatively small number of turns.

共振や同調、発振などの用途で高周波コイルを用いる場
合、コイルとコンデンサでタンク回路を構成する０周知
の通り、タンク回路の周波数ｆは次式で与えられる。When a high-frequency coil is used for purposes such as resonance, tuning, and oscillation, the coil and capacitor constitute a tank circuit.As is well known, the frequency f of the tank circuit is given by the following equation.

ｆ　　＝　　１　　／　　　（２π　ｆボッσ　）ここ
でＬはコイルのインダクタンス、Ｃはコンデンサの容量
である。f = 1 / (2π f σ ) where L is the inductance of the coil, and C is the capacitance of the capacitor.

周波数調整においてはコイルのインダクタンスＬを一定
にして、コンデンサの容ｆｌｃをトリマコンデンサなど
で可変することが一般的である。In frequency adjustment, it is common to keep the inductance L of the coil constant and to vary the capacitance flc using a trimmer capacitor or the like.

また一方、コンデンサの容ｔｃを一定にし、コイルのイ
ンダクタンスＬを変化させることによって周波数調整を
行う方式がある。短波帯以下の場合はコイル内部のコア
の位置を変えることによって容易に調整できるが、短波
帯以上の空芯コイルではこの手段を用いることができな
いため、巻数や巻径、ピッチなどコイルの形状に関する
点を変更する方法がある。On the other hand, there is a method in which the frequency is adjusted by keeping the capacitor capacitance tc constant and changing the coil inductance L. For frequencies below the shortwave band, it can be easily adjusted by changing the position of the core inside the coil, but this method cannot be used for air-core coils for frequencies above the shortwave band, so it is difficult to adjust the coil shape, such as the number of turns, winding diameter, and pitch. There is a way to change the points.

高周波コイルの調整として一般的な空芯コイルのピッチ
を変える方法について第２図を用いて説明する。第２図
（ａ）のように雑音除去の目的で回路をシールドケース
】で包囲している場合は調整用ドライバ９が出入りでき
る程度の調整穴ｌＯを設けておく、調整用ドライバ９を
コイルの巻線間に挿入し、第２図（ｂ）の様に切線の間
隔を広げることにより、インダクタンスを減少させるこ
とができる。A method of changing the pitch of a general air-core coil as an adjustment of a high-frequency coil will be explained using FIG. 2. If the circuit is surrounded by a shield case for the purpose of noise removal, as shown in Fig. 2(a), an adjustment hole lO should be provided to allow the adjustment driver 9 to go in and out. Inductance can be reduced by inserting it between the windings and widening the interval between the cutting lines as shown in FIG. 2(b).

［発明が解決しようとする問題］近年、伝送線路が大幅に短縮できることから、高周波回
路にも高密度実装方式が取り入れられており、トリマコ
ンデンサは比較的大きな部品のため、高密度実装を行う
上で不都合である。このため、短波帯以上の高周波回路
ではインダクタンス■、を可変にする方式が有利である
。[Problem to be solved by the invention] In recent years, high-density mounting methods have been adopted in high-frequency circuits as transmission lines can be significantly shortened, and trimmer capacitors are relatively large components, so it is difficult to implement high-density mounting. This is inconvenient. For this reason, it is advantageous to make the inductance (2) variable in high frequency circuits in the short wave band or higher.

コイルのインダクタンスＬを変化させることによって周
波数調整を行う方式では、空芯コイルの巻数、巻径、ピ
ッチなどコイルの形状に関する点を変更せざるをえず、
正確な調整が困難で手間がかかり、経時変化も大きい等
の問題がある。In the method of adjusting the frequency by changing the inductance L of the coil, it is necessary to change the shape of the air-core coil, such as the number of turns, the winding diameter, and the pitch.
There are problems such as accurate adjustment is difficult and time consuming, and changes over time are large.

例えばコイルの巻径、巻数を変えて調整する方法では、
−旦基板に装着したコイルを外し、巻径や巻数が適切な
コイルに取り替える必要がある。For example, when adjusting by changing the coil diameter and number of turns,
- It is necessary to remove the coil attached to the board and replace it with a coil with an appropriate winding diameter and number of turns.

ところが、コイル部品はインダクタンスのバラツキが大
きいため、この方法を行うと取り替え作業の手間が大き
く、精密な調整も囚デｔである。However, since coil parts have large variations in inductance, using this method requires a lot of effort to replace them, and precise adjustment is also difficult.

コイルのピッチを変える方法によればコイルを取り替え
る必要はないが、精密な調整には熟練を要す、またコイ
ルを無理に変形させるため、ビツヂの戻りが現れ調整周
波数がずれ、不安定要因となるばかりでなく、振動、衝
撃に対しても変動が生じる。The method of changing the pitch of the coil does not require replacing the coil, but precision adjustment requires skill, and since the coil is forcibly deformed, the pitch may return and the adjusted frequency may shift, causing instability. Not only this, but also fluctuations occur due to vibrations and shocks.

この発明はこの問題を克服すべく考案されたもので、高
周波用空芯コイルにインダクタンス調整機構を設けるこ
とにより、周波数設定を安定がっ精密に行うことができ
、併せて調整作業を簡単化できることにより、信頼性の
高い優れた高周波コイルを提供することを目的とする。This invention was devised to overcome this problem, and by providing an inductance adjustment mechanism in the high-frequency air-core coil, frequency setting can be performed stably and precisely, and the adjustment work can also be simplified. Our goal is to provide excellent high-frequency coils with high reliability.

［問題を解決するための手段］この発明は、空芯コイルのコイル同軸方向の延長線上に
ネジを支え、さらに固定するための支持体を設け、コイ
ルの同軸中心に対向する部分にネジ穴を施し、ネジ穴に
金属などの導電性のネジを差し込み、ネジの先端がコイ
ルに対向する配置を構成する。[Means for solving the problem] The present invention provides a support for supporting and further fixing a screw on an extension of the air-core coil in the coaxial direction of the coil, and a screw hole is provided in a portion facing the coaxial center of the coil. Insert a conductive screw made of metal or other material into the screw hole so that the tip of the screw faces the coil.

［作用］上記のように構成したこの発明によれば、コイルから発
生される高周波交番磁界によって、導電体でできたネジ
の内部に渦電流が生じ、反抗磁界を発生する。渦電流に
よる反磁界は短波帯以上の周波数帯域では無視できない
大きさになるため、コイルに鎖交する磁束密度は減少す
る。これによりコイルのインダクタンスが減少するため
、発振周波数は上昇する。[Operation] According to the present invention configured as described above, an eddy current is generated inside the screw made of a conductive material by the high frequency alternating magnetic field generated from the coil, and a countermagnetic field is generated. Since the demagnetizing field caused by the eddy current becomes large enough to not be ignored in the frequency band above the short wave band, the magnetic flux density interlinking with the coil decreases. This reduces the inductance of the coil, thereby increasing the oscillation frequency.

ネジとコイルの相対位置を変化させることにより、周波
数上昇分を正確に調整することができ、また、調整後は
ネジを接着剤や半田、溶接などで支持体に固定すること
により、外部環境の変動に対しても安定に動作するよう
になる。By changing the relative position of the screw and the coil, the frequency increase can be adjusted accurately.After adjustment, the screw can be fixed to the support with adhesive, solder, welding, etc. to adjust the external environment. It will operate stably even in the face of fluctuations.

この発明によれば、通信機器をはじめとする高周波の発
振周波数が安定し、製品相互間のバラツキも少なくなり
、ひいては色々の機器の作動における高い信頼性が得ら
れるといった優れた効果を奏する高周波コイルを提供す
ることができる。According to this invention, a high-frequency coil has excellent effects such as stabilizing the oscillation frequency of high-frequency waves such as communication equipment, reducing variations between products, and achieving high reliability in the operation of various equipment. can be provided.

［実施例］以下この発明の実施例を図面に基づいて説明する。第一
図に本発明の実施例を示し、同図（ａ）にその断面図、
同図（ｂ）に正面図を示す。[Example] Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 shows an embodiment of the present invention, and FIG.
A front view is shown in the same figure (b).

この実施例は調整ネジ２の支持体として、高周波発振回
路の雑音対策に使われるシールドケース１で代用してい
る。In this embodiment, a shield case 1 used for noise countermeasures in high frequency oscillation circuits is used as a support for the adjustment screw 2.

予め空芯コイル５をシールドケース１の近辺に配置され
るように設計しておく、空芯コイル５は回路基板４に半
田付は部６によって固定し、更に回路基板４の裏面の銅
箔７とシールドケース１とを半田付け８で固定すること
により、空芯コイル５に及ぼす周囲の影響を固定する。The air-core coil 5 is designed in advance to be placed near the shield case 1. The air-core coil 5 is fixed to the circuit board 4 by soldering using the part 6, and is further fixed to the copper foil 7 on the back side of the circuit board 4. By fixing the and shield case 1 with soldering 8, the influence of the surroundings on the air-core coil 5 is fixed.

空芯コイル５の同軸中心の延長線とシールドケース１の
交差する点にネジ穴３を設ける。ネジ穴３は貫通穴にめ
ねじを切っても良いし、ナツトを接着固定しても良い、
このネジ穴は導電性の調整ネジ２を挿入し、支持するこ
とを目的とする。これによって、外部から調整ネジ２の
ネジ頭をドライバで回すことでネジの先端部と空芯コイ
ル５の春日との間隔を変えることができる。A screw hole 3 is provided at a point where an extension of the coaxial center of the air-core coil 5 and the shield case 1 intersect. For the screw hole 3, a female thread may be cut into the through hole, or a nut may be fixed with adhesive.
The purpose of this screw hole is to insert and support a conductive adjustment screw 2. Thereby, by turning the screw head of the adjustment screw 2 from the outside with a screwdriver, the distance between the tip of the screw and the spring of the air-core coil 5 can be changed.

［発明の効果］調整ネジを空芯コイルに近付けると発振周波数は上昇し
、遠ざけると下降する。調整ネジを取り去った場合が最
も発振周波数が低くなるため、この状態で目標とする発
振周波数を越えないよう、予め空芯コイルのインダクタ
ンスを大きめに設計することが必要である。[Effects of the Invention] When the adjustment screw is brought closer to the air-core coil, the oscillation frequency increases, and when it is moved away from it, it decreases. Since the oscillation frequency is the lowest when the adjustment screw is removed, it is necessary to design the inductance of the air-core coil to be large in advance so as not to exceed the target oscillation frequency in this state.

金属ネジを取付ける支持体は、高周波回路によく用いら
れるシールドケースで代用することができ、特に局部発
振回路等の外部雑音を除外したい用途に用いることがで
きる。ネジ頭がケース外部に突出するため、回路をケー
スに封入した後、金属ケースの影響でインダクタンスが
変動しても再調整が行える利点を持つ、さらに、この場
合、トリマコンデンサ等で調整する場合に比べて、シー
ルドケースにドライバが通る程度め調整用の穴を設ける
必要がなく、完全密閉することができるため外部ｍｆの
侵入を防止することができる。よって、■ＣＯのように
外部雑音を極度に嫌い、安定性、高精度の設定性が求め
られる高周波発振回路に適している。The support body to which the metal screws are attached can be replaced by a shield case often used in high frequency circuits, and can be used particularly in applications where it is desired to exclude external noise such as local oscillation circuits. Since the screw head protrudes outside the case, it has the advantage of being able to be readjusted even if the inductance changes due to the influence of the metal case after the circuit is sealed in the case.Furthermore, in this case, when adjusting with a trimmer capacitor etc. In comparison, there is no need to provide a hole in the shield case for adjusting the degree through which the driver passes, and the shield case can be completely sealed, thereby preventing intrusion of external mF. Therefore, it is suitable for high frequency oscillation circuits such as CO, which are extremely sensitive to external noise and require stability and highly accurate setting.

第１図の実施例では、目標とする発振周波数を３６０Ｍ
Ｈｚとして、調整ネジ１回転で約ＩＭＨ２の調整が可能
で、ｌ０ＫＩ−Ｔｚの精度での精密調整が可能となった
。In the example shown in Fig. 1, the target oscillation frequency is 360M.
In terms of Hz, it is possible to adjust approximately IMH2 with one rotation of the adjustment screw, allowing precise adjustment with an accuracy of 10KI-Tz.

なお調整ネジに鉄等の磁性体を用いた場合、非線形歪み
やバルクハウゼン雑音等の影響により不要輻射が増加し
、Ｃ／Ｎ比やＳ／Ｎ比に劣化を来すため、黄銅等の非磁
性体を用いることで良好な結果が得られる。If a magnetic material such as iron is used for the adjustment screw, unnecessary radiation will increase due to the effects of nonlinear distortion and Barkhausen noise, resulting in deterioration of the C/N ratio and S/N ratio. Good results can be obtained by using magnetic materials.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の実施例を示す図で、同図（ａ）は部分
側断面図、同図（ｂ）は正面図である。第２図は、来の調整方法を示す部分側断面図で、同図（
ａ）は調整時の状態、同図（ｂ）は調整後の状態を示す
６１・・・シールドケース、２・・・調整ネジ、３・・・
ネジ穴、４・・・回路基板、５・・・空芯コイル、６・
・・半田付は部、７・・・銅箔、８・・・半田付は部、
９・・・調整用ドライバ、１０・・・調整穴（ａ）（ｂ）第１図FIG. 1 is a diagram showing an embodiment of the present invention, with FIG. 1(a) being a partial side sectional view and FIG. 1(b) being a front view. Figure 2 is a partial side sectional view showing the previous adjustment method;
Figure a) shows the state at the time of adjustment, and figure (b) shows the state after adjustment 6 1... Shield case, 2... Adjustment screw, 3...
Screw hole, 4... Circuit board, 5... Air core coil, 6...
...Soldering is part, 7...Copper foil, 8...Soldering is part,
9...adjustment driver, 10...adjustment hole (a) (b) Fig. 1

Claims (1)

Translated fromJapanese

【特許請求の範囲】[Claims]　空芯コイルのコイル同軸方向の延長線上に、ネジ穴を
施した支持体を設け、調整ネジが前記ネジ穴に回動自在
に取付けられた事を特徴とする可変インダクタンス。A variable inductance characterized in that a support body provided with a screw hole is provided on an extension line of an air-core coil in a coaxial direction of the coil, and an adjustment screw is rotatably attached to the screw hole.