JPS642254Y2 - - Google Patents
Info
- Publication number
- JPS642254Y2 JPS642254Y2 JP12996980U JP12996980U JPS642254Y2 JP S642254 Y2 JPS642254 Y2 JP S642254Y2 JP 12996980 U JP12996980 U JP 12996980U JP 12996980 U JP12996980 U JP 12996980U JP S642254 Y2 JPS642254 Y2 JP S642254Y2
- Authority
- JP
- Japan
- Prior art keywords
- shield case
- edge
- head
- playback head
- magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000003780 insertion Methods 0.000 claims description 4
- 230000037431 insertion Effects 0.000 claims description 4
- 230000004907 flux Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 229910000889 permalloy Inorganic materials 0.000 description 1
Description
【考案の詳細な説明】
本考案は磁気ヘツドのシールドケースに関する
ものである。[Detailed Description of the Invention] The present invention relates to a shielding case for a magnetic head.
一般にテープレコーダの再生ヘツドは、外部誘
導ノイズのレベルを下げるためシールドケースに
納められている。上記シールドケースに収納され
た再生ヘツドの外側にさらにシールドケースをか
ぶせて二重にシールドしたものも知られている。
この一例として第１図に示すように、磁気テープ
１を走行させるための切欠き２を設けた外部シー
ルドケース３に、内部シールドケース４を納めた
再生ヘツド５を収納したものがある。 Generally, the playback head of a tape recorder is housed in a shield case to reduce the level of externally induced noise. It is also known that a shield case is further placed over the outside of the playback head housed in the shield case to provide double shielding.
An example of this is shown in FIG. 1, in which a reproducing head 5 containing an inner shield case 4 is housed in an outer shield case 3 provided with a notch 2 for running a magnetic tape 1.
上記第１図に示した二重にシールドされた再生
ヘツドにおいて、例えばキヤンセル巻きの再生ヘ
ツドでは、正面からの外部誘導ノイズはキヤンセ
ルできるが、横からの外部誘導ノイズに対して十
分にキヤンセルできないという欠点があつた。こ
の横からの外部誘導ノイズのレベルを下げるため
には、例えば第２図に示すように、切欠き２の縁
部６が走行中の磁気テープ１に当たらない程度
に、又内部シールドケース４の稜７よりも少し前
に出るように、すなわち、切欠き２の側面におけ
る間口を小さくして、遮蔽面積を大きくすればよ
い。しかし、一般に、内部シールドケースの稜７
は、形状効果、すなわち、磁気テープと接触する
再生ヘツド前面の形状から起る損失であつて、磁
気テープからの磁束が長波長となるとヘツドのギ
ヤツプから入る磁束と、コアの端から入る磁束が
互いに干渉し合い、録音波長によつてコイル内を
通る磁束が増加したり、減少したりして周波数特
性に山谷（うねり）が生じることを考慮して定め
られている。したがつて、切欠き２における縁部
６を稜７より磁気テープ１側に形成して、外部シ
ールドケース３によつて稜７を全部、遮蔽するこ
とは、再生ヘツド前面の形状に間接的に変化を与
え、低域の周波数特性に大きな影響を及ぼし、実
用上好ましくない。 In the double-shielded playback head shown in Figure 1 above, for example, a cancelled-wound playback head can cancel externally induced noise from the front, but cannot sufficiently cancel externally induced noise from the sides. There were flaws. In order to reduce the level of externally induced noise from the side, for example, as shown in FIG. The shielding area may be increased by making the cutout 2 appear slightly in front of the edge 7, that is, by making the opening on the side surface of the notch 2 smaller. However, in general, the edge 7 of the inner shield case
is a loss caused by the shape effect, that is, the shape of the front surface of the playback head that comes into contact with the magnetic tape, and when the magnetic flux from the magnetic tape has a long wavelength, the magnetic flux entering from the gap of the head and the magnetic flux entering from the end of the core are This is determined in consideration of the fact that they interfere with each other, and that the magnetic flux passing through the coil increases or decreases depending on the recording wavelength, causing peaks and troughs (undulations) in the frequency characteristics. Therefore, forming the edge 6 of the notch 2 closer to the magnetic tape 1 than the edge 7 and completely shielding the edge 7 with the external shield case 3 indirectly affects the shape of the front surface of the playback head. This is undesirable for practical use because it has a large effect on the low frequency characteristics.
上記したことを鑑みて、本考案は成されたもの
であり、再生ヘツドに対する横からの外部誘導ノ
イズのレベルを低減し、かつ低域の周波数特性に
大きな影響を与えない磁気ヘツドのシールドケー
スを提供するものである。 In view of the above, the present invention was developed to provide a magnetic head shielding case that reduces the level of externally induced noise from the side of the playback head and does not significantly affect the low frequency characteristics. This is what we provide.
以下本考案の実施例を説明する。第３図に示す
ように、８はパーマロイ等により成る外部シール
ドケースである。外部シールドケース８にはテー
プ挿入溝９が設けられている。テープ挿入溝９の
縁部１０は、内部シールドケース４の稜７より磁
気テープ１に近い位置に形成されている。すなわ
ち、縁部１０は、第４図に示すように、再生ヘツ
ド５を外部シールドケース８内に取り付けたと
き、内部シールドケース４の稜７よりも少し前に
出る程度に、又走行中の磁気テープ１が当たらな
い程度に設ける。縁部１０には、高さが再生ヘツ
ド５のコア幅と略同じで、間口が稜７を目視でき
る大きさである切欠き１１，１２が形成されてい
る。すなわち、切欠き１１，１２は、第４図に示
すように、再生ヘツド５を外部シールドケース８
内に取り付けたとき、再生ヘツド５のコア１３，
１４と同じ位置に、上記コアのコア幅と同じ幅で
切欠いたものである。この切欠き１１，１２の縁
部１５は、内部シールドケース４の稜７よりも磁
気テープ１から離れた位置にある。このように構
成されているので、内部シールドケース４を外部
シールドケース８に装着したとき、内部シールド
ケース４の稜７は、一部は遮蔽され、一部は露呈
している。したがつて、稜７を遮蔽する面積は、
従来に比較して増大するから、横からの外部誘導
ノイズのレベルを下げることができる。また、稜
７は全部、遮蔽されていないので、再生ヘツド前
面の形状に間接的に変化を与えるといつても、低
域の周波数特性に対する影響は軽減される。 Examples of the present invention will be described below. As shown in FIG. 3, 8 is an external shield case made of permalloy or the like. The external shield case 8 is provided with a tape insertion groove 9. The edge 10 of the tape insertion groove 9 is formed closer to the magnetic tape 1 than the edge 7 of the internal shield case 4. That is, as shown in FIG. 4, when the reproducing head 5 is installed in the outer shield case 8, the edge 10 extends slightly in front of the edge 7 of the inner shield case 4, and the edge 10 is formed so that it is exposed to the magnetic field while the head is running. Provide it so that the tape 1 does not touch it. Cutouts 11 and 12 are formed in the edge 10, the height of which is approximately the same as the core width of the reproducing head 5, and the opening of which is large enough to allow the ridge 7 to be viewed visually. That is, the notches 11 and 12 are used to connect the playback head 5 to the external shield case 8, as shown in FIG.
When installed in the core 13 of the playback head 5,
A cutout is made at the same position as No. 14 and with the same width as the core width of the above core. Edges 15 of the notches 11 and 12 are located further away from the magnetic tape 1 than the edge 7 of the internal shield case 4. With this structure, when the internal shield case 4 is attached to the external shield case 8, the ridge 7 of the internal shield case 4 is partly shielded and partly exposed. Therefore, the area that shields the edge 7 is
Since this increases compared to the conventional case, the level of externally induced noise from the side can be lowered. Moreover, since the edges 7 are not entirely shielded, even if the shape of the front surface of the reproducing head is indirectly changed, the influence on the low frequency characteristics is reduced.
尚、上記実施例は再生ヘツドについて説明した
が録音・再生兼用の磁気ヘツドでも実施できる。 Although the above embodiment has been described with respect to a reproducing head, it can also be implemented with a magnetic head for both recording and reproducing purposes.
上記したように、この考案による磁気ヘツドの
シールドケースは、再生ヘツドに対する横からの
外部誘導ノイズのレベルを下げることができ、か
つ低域の周波数特性に対する影響を軽減すること
がきる。尚実際に行つた結果、磁界1.18oeの平行
磁界中において、
従 来 本考案
−74.3dbs −75.7dbs 1dbs＝0.775V
となり、1.4dbsの改善がみられた。 As described above, the magnetic head shielding case according to this invention can lower the level of external induced noise from the side of the reproducing head, and can also reduce the influence on the low frequency characteristics. As a result of actual testing, in a parallel magnetic field with a magnetic field of 1.18 oe, the current value was −74.3 dbs −75.7 dbs 1 dbs = 0.775 V, which was an improvement of 1.4 dbs.
第１図は従来の二重にシールドした再生ヘツド
の側面図、第２図は本考案を説明するための再生
ヘツドの横断平面図、第３図は本考案の一実施例
を示すシールドケースと再生ヘツドの分解斜視
図、第４図は本考案のシールドケースに再生ヘツ
ドを収納した側面図である。
１：磁気テープ、４：内部シールドケース、
５：再生ヘツド、７：稜、８：外部シールドケー
ス、９：テープ挿入溝、１０，１５：縁部、１
１，１２：切欠き、１３，１４：コア。
Fig. 1 is a side view of a conventional double-shielded playback head, Fig. 2 is a cross-sectional plan view of the playback head for explaining the present invention, and Fig. 3 is a shield case showing an embodiment of the present invention. FIG. 4 is an exploded perspective view of the playback head, and FIG. 4 is a side view of the playback head housed in the shield case of the present invention. 1: Magnetic tape, 4: Internal shield case,
5: Playback head, 7: Edge, 8: External shield case, 9: Tape insertion groove, 10, 15: Edge, 1
1, 12: Notch, 13, 14: Core.
Claims (1)
納するシールドケースにおいて、磁気テープを挿
通移動させるテープ挿入溝の縁部を上記内部シー
ルドケースの稜より磁気テープに近い位置に形成
するととともに、高さが該再生ヘツドのコア幅と
略同じで、間口が該稜を目視できる大きさである
切欠きを該縁部に形成したことを特徴とする磁気
ヘツドのシールドケース。 In a shield case that houses a playback head surrounded by an internal shield case, the edge of the tape insertion groove through which the magnetic tape is inserted and moved is formed at a position closer to the magnetic tape than the edge of the internal shield case, and the height is adjusted to meet the required height. 1. A shield case for a magnetic head, characterized in that a notch is formed at the edge of the playback head, the width being approximately the same as the core width of the playback head, and having a frontage large enough to allow the ridge to be viewed visually.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12996980U JPS642254Y2 (en) | 1980-09-11 | 1980-09-11 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12996980U JPS642254Y2 (en) | 1980-09-11 | 1980-09-11 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5753233U JPS5753233U (en) | 1982-03-27 |
| JPS642254Y2 true JPS642254Y2 (en) | 1989-01-19 |
Family
ID=29490297
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12996980U Expired JPS642254Y2 (en) | 1980-09-11 | 1980-09-11 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS642254Y2 (en) |
-
1980
- 1980-09-11 JP JP12996980U patent/JPS642254Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5753233U (en) | 1982-03-27 |
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