JPH0338521Y2 - - Google Patents
Info
- Publication number
- JPH0338521Y2 JPH0338521Y2 JP19701686U JP19701686U JPH0338521Y2 JP H0338521 Y2 JPH0338521 Y2 JP H0338521Y2 JP 19701686 U JP19701686 U JP 19701686U JP 19701686 U JP19701686 U JP 19701686U JP H0338521 Y2 JPH0338521 Y2 JP H0338521Y2
- Authority
- JP
- Japan
- Prior art keywords
- permanent magnet
- shaft
- pole piece
- magnetic flux
- 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
- 230000004907 flux Effects 0.000 claims description 25
- 239000011553 magnetic fluid Substances 0.000 claims description 17
- 238000007789 sealing Methods 0.000 claims description 4
- 230000000903 blocking effect Effects 0.000 claims description 3
- BGPVFRJUHWVFKM-UHFFFAOYSA-N N1=C2C=CC=CC2=[N+]([O-])C1(CC1)CCC21N=C1C=CC=CC1=[N+]2[O-] Chemical compound N1=C2C=CC=CC2=[N+]([O-])C1(CC1)CCC21N=C1C=CC=CC1=[N+]2[O-] BGPVFRJUHWVFKM-UHFFFAOYSA-N 0.000 description 5
- 230000005415 magnetization Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 230000003749 cleanliness Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
Landscapes
- Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
Description
【考案の詳細な説明】
本考案は、磁気記録媒体としてのハードデイス
クの回転軸の密閉構造に適用して好適な磁性流体
シール装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic fluid sealing device suitable for application to a sealed structure for a rotating shaft of a hard disk as a magnetic recording medium.
磁気記録媒体としてのハードデイスクは、その
信頼性を向上させるために種々の改良が行なわれ
ている。例えば、デイスクが内蔵されたデイスク
パツク内の空間の清浄度が特に重要である。この
清浄度を保つためには、デイスクのスピンドル部
に磁性流体シールが取り付けられ、デイスクパツ
ク内にスピンドルのベアリングのグリースのミス
ト又はデイスクパツクの外部からの塵埃が侵入し
ないように改良されている。 Various improvements have been made to hard disks as magnetic recording media to improve their reliability. For example, the cleanliness of the space inside the disk pack containing the disk is particularly important. In order to maintain this cleanliness, a magnetic fluid seal is attached to the spindle of the disk to prevent grease mist from the spindle bearings or dust from outside the disk pack from entering the disk pack.
しかし、ハードデイスクの小型化・薄型化の傾
向により、磁性流体シールにも小型化・薄型化が
要求されているが、小型化に伴なつて磁性流体シ
ール自体の漏洩磁束が問題になつている。 However, as hard disks tend to become smaller and thinner, magnetic fluid seals are also required to be smaller and thinner, but with the miniaturization, magnetic flux leakage from the magnetic fluid seal itself has become a problem.
すなわち従来の磁性流体シールの構造は、例え
ば第１図に示す如く、軟磁性の軸３と、２枚の環
状のポールピース２と、その間にはさんで軸方向
に磁化している永久磁石１と、空隙に磁気的に捕
捉された磁性流体膜４からなる。 That is, the structure of a conventional magnetic fluid seal, for example, as shown in FIG. 1, consists of a soft magnetic shaft 3, two annular pole pieces 2, and a permanent magnet 1 sandwiched between them and magnetized in the axial direction. and a magnetic fluid film 4 magnetically trapped in the air gap.
このような構造によれば、シールの外形（径方
向）部より漏洩磁界の発生が生じ、他の電子部品
に悪影響を及ぼす欠点が生ずる。 According to such a structure, a leakage magnetic field is generated from the outer (radial direction) portion of the seal, resulting in a disadvantage that it adversely affects other electronic components.
そこで、第２図に示す如く、半径方向に磁化さ
れた永久磁石１及びこの永久磁石により側面へ発
生する漏洩磁束をさえぎるための環状部を有する
環状のポールピース２が設けられ、ポールピース
２と軸３との間、永久磁石１と軸３との間には磁
性流体４が磁気的に補捉されるように構成するこ
とにより、上記の欠点を解消することを目的とし
たものがある。（例えば特願昭60−170665）
しかし、第２図の構造においては、永久磁石１
とポールピース２との間に形成される空間Ｒは、
磁化回路的にシール耐圧向上に充分利用されてい
ないという欠点がある。 Therefore, as shown in FIG. 2, a permanent magnet 1 magnetized in the radial direction and an annular pole piece 2 having an annular portion for blocking leakage magnetic flux generated toward the side surface by the permanent magnet are provided. Some devices are designed to solve the above-mentioned drawbacks by configuring the magnetic fluid 4 to be magnetically captured between the permanent magnet 1 and the shaft 3. (For example, Japanese Patent Application No. 60-170665) However, in the structure shown in Fig. 2, the permanent magnet 1
The space R formed between and the pole piece 2 is
The drawback is that it is not fully utilized for improving the seal pressure resistance in terms of magnetization circuits.
本考案はかかる点に鑑み、該空間Ｒに軸方向に
磁化した永久磁石を挿入することにより、磁気回
路的に未使用であつた空間Ｒをシール耐圧向上に
充分に利用した磁性流体シール装置を提案するこ
とを主たる目的とする。 In view of this, the present invention provides a magnetic fluid sealing device that fully utilizes the unused space R in terms of the magnetic circuit to improve seal pressure resistance by inserting a permanent magnet magnetized in the axial direction into the space R. The main purpose is to make suggestions.
以下本考案の一実施例について図面を参照しな
がら詳細に説明する。 An embodiment of the present invention will be described in detail below with reference to the drawings.
第３図は本考案の一例を示す図である。３は軟
磁性の軸を示し、軸３には半径方向に磁化された
環状永久磁石１と、磁石１の平面部と密着して軸
方向に磁化された環状永久磁石５と、磁石５の他
端の平面部と密着し、永久磁石１及び磁石５の外
径部を包含している断面Ｌ字形の軟磁性体ポール
ピース２とが設けられている。そしてポールピー
ス２と軸３との間、永久磁石と１と軸３との間に
は、磁性流体４が磁気的に補足されている。 FIG. 3 is a diagram showing an example of the present invention. Reference numeral 3 indicates a soft magnetic shaft, and the shaft 3 includes an annular permanent magnet 1 that is magnetized in the radial direction, an annular permanent magnet 5 that is in close contact with the flat surface of the magnet 1 and is magnetized in the axial direction, and the other magnets 5. A soft magnetic pole piece 2 having an L-shaped cross section and closely contacting the flat end portion and encompassing the outer diameter portions of the permanent magnet 1 and the magnet 5 is provided. A magnetic fluid 4 is magnetically captured between the pole piece 2 and the shaft 3, and between the permanent magnet 1 and the shaft 3.
したがつて、第３図において右側及び径方向の
永久磁石１，５による漏洩磁束は、ポールピース
２により遮蔽されることになる。ところが、左側
へは漏洩磁束が発生する。この漏洩に関する効果
は従来の第２図の構造のものと同一である。 Therefore, leakage magnetic flux caused by the permanent magnets 1 and 5 on the right side and in the radial direction in FIG. 3 is shielded by the pole piece 2. However, leakage magnetic flux occurs to the left. The effect regarding this leakage is the same as that of the conventional structure shown in FIG.
しかし、軸方向に磁化された磁石５が第２図に
おける空間Ｒ部に挿入されたことにより、磁石５
より供給される磁束の一部がポールピース２と軸
３のギヤツプを通過する磁束に寄与することにな
り、磁石１により供給されるポールピース２と軸
３との間のギヤツプを通過する磁束に加わるの
で、結果としてポールピース２と軸３のギヤツプ
間の磁束密度が増加し、したがつて、該ギヤツプ
部の磁性流体膜４のシール耐圧が増加するように
なる。 However, since the magnet 5 magnetized in the axial direction is inserted into the space R in FIG.
A part of the magnetic flux supplied by the magnet 1 contributes to the magnetic flux passing through the gap between the pole piece 2 and the shaft 3, and a part of the magnetic flux supplied by the magnet 1 contributes to the magnetic flux passing through the gap between the pole piece 2 and the shaft 3. As a result, the magnetic flux density between the gap between the pole piece 2 and the shaft 3 increases, and the sealing pressure of the magnetic fluid film 4 at the gap increases.
ちなみに、軸方向に磁化された磁石５の磁化ベ
クトルの向きは、磁石５よりポールピース２と軸
３のギヤツプ通過する磁束が磁石１により供給さ
れ、ポールピース２と軸３のギヤツプ通過する磁
束と相加するように選ばれている。 Incidentally, the direction of the magnetization vector of the magnet 5 magnetized in the axial direction is such that the magnetic flux passing through the gap between the pole piece 2 and the shaft 3 is supplied by the magnet 1, and the magnetic flux passing through the gap between the pole piece 2 and the shaft 3 is are chosen to be additive.
同様に、磁石１と軸３との間のギヤツプに対し
ても、永久磁石５のポールピース２と密着してい
る面と反対側の平面部より発生する漏洩磁束の一
部が、永久磁石１より起因する該ギヤツプ部を通
過する磁束と相加するので、該ギヤツプの磁束密
度が増加し耐圧が向上することになる。 Similarly, with respect to the gap between the magnet 1 and the shaft 3, a part of the leakage magnetic flux generated from the flat part of the permanent magnet 5 opposite to the surface that is in close contact with the pole piece 2 is transmitted to the permanent magnet 1. Since the magnetic flux is added to the magnetic flux passing through the gap due to the magnetic flux, the magnetic flux density of the gap increases and the withstand voltage improves.
第４図は本考案の更に他の例を示す断面図であ
る。本例においては、第３図における第１及び第
２の永久磁石１，５を実質的に一体化した永久磁
石６を磁石１，５の代わりに使用している。永久
磁石６の磁化は、第４図に示す如く、弓型に磁化
される。すなわち永久磁石６のポールピース２に
密着している地点より左側へ行くにつれて軸方向
へ向いている磁化ベクトルが次第に半径方向へ向
く円弧状の磁化ベクトルとなるように磁化され
る。したがつて、第３図における永久磁石１及び
２を磁気回路的に一体化したものと同等の磁化ベ
クトルの作用となる。 FIG. 4 is a sectional view showing still another example of the present invention. In this example, a permanent magnet 6, which is a substantially integrated structure of the first and second permanent magnets 1 and 5 shown in FIG. 3, is used in place of the magnets 1 and 5. The permanent magnet 6 is magnetized in a bow shape, as shown in FIG. That is, as the permanent magnet 6 moves to the left from the point where it is in close contact with the pole piece 2, the magnetization vector that is oriented in the axial direction gradually becomes an arc-shaped magnetization vector that is oriented in the radial direction. Therefore, the effect of the magnetization vector is equivalent to that of the permanent magnets 1 and 2 shown in FIG. 3 integrated in a magnetic circuit.
以上述べたごとく本考案によれば、半径方向に
磁化された第１の環状永久磁石と、第１の永久磁
石と別体又は一体に軸方向に磁化された第２の環
状永久磁石と、該第２の磁石の平面部と密着し、
第１及び第２の永久磁石の外径部を包含して、第
１の永久磁石の側面より発生する漏洩磁束をさえ
ぎるための環状部を有するポールピースを設け、
上記ポールピースと軟磁性軸との間、及び上記第
１の永久磁石と軟磁性軸との間に夫々磁性流体を
磁気的に捕捉するように構成したので、
上記永久磁石群によつて発生する漏洩磁束は、
一方が上記ポールピースを通過し他方は外部へ漏
洩することになるが、上記第１の永久磁石の径方
向についてはポールピースが覆つているため、ポ
ールピースの外側への漏洩磁束は発生しないよう
になり、小型化に伴なう磁性流体シール機構の漏
洩磁束の問題は解消することになる。 As described above, according to the present invention, the first annular permanent magnet is magnetized in the radial direction, the second annular permanent magnet is magnetized in the axial direction separately or integrally with the first permanent magnet, and the second annular permanent magnet is magnetized in the axial direction. In close contact with the flat part of the second magnet,
providing a pole piece that includes the outer diameter portions of the first and second permanent magnets and has an annular portion for blocking leakage magnetic flux generated from the side surface of the first permanent magnet;
Since the magnetic fluid is magnetically captured between the pole piece and the soft magnetic shaft and between the first permanent magnet and the soft magnetic shaft, the magnetic fluid generated by the permanent magnet group is The leakage magnetic flux is
One side passes through the pole piece and the other side leaks to the outside, but since the pole piece covers the first permanent magnet in the radial direction, no magnetic flux leaks to the outside of the pole piece. This solves the problem of magnetic flux leakage from the magnetic fluid seal mechanism that accompanies miniaturization.
更に、従来利用されていなかつた空間に、上記
軸方向に磁化された第２の永久磁石を充填してい
るので、この永久磁石より供給される磁束の一部
を耐圧方向に寄与する磁性流体が磁気的に保持さ
れる。したがつて、該ポールピースと軸とのギヤ
ツプ部の磁束密度及び該半径方向に磁化された永
久磁石と軸とのギヤツプ部の磁束密度の増加に利
用できる効果を有する。したがつて本考案によれ
ば、小型にしても漏洩磁束が少なくなるので、よ
り小型のシール構造を提供することが可能とな
る。 Furthermore, since the space previously unused is filled with the second permanent magnet magnetized in the axial direction, a part of the magnetic flux supplied by this permanent magnet is transferred to the magnetic fluid that contributes to the pressure resistance direction. held magnetically. Therefore, it has an effect that can be used to increase the magnetic flux density in the gap between the pole piece and the shaft and the magnetic flux density in the gap between the radially magnetized permanent magnet and the shaft. Therefore, according to the present invention, leakage magnetic flux is reduced even if the seal structure is made smaller, so that it is possible to provide a smaller seal structure.
第１図及び第２図は従来の構成を示す断面図、
第３図は本考案の一実施例を示す断面図、第４図
は本考案の他の例を示す図である。
１……第１の永久磁石、２……環状ポールピー
ス、３……軟磁性軸、４……磁性流体、５……第
２の永久磁石。
Figures 1 and 2 are cross-sectional views showing the conventional configuration;
FIG. 3 is a sectional view showing one embodiment of the present invention, and FIG. 4 is a diagram showing another example of the present invention. DESCRIPTION OF SYMBOLS 1... First permanent magnet, 2... Annular pole piece, 3... Soft magnetic shaft, 4... Magnetic fluid, 5... Second permanent magnet.
Claims (1)
第１の永久磁石と別体又は一体に軸方向に磁化さ
れた第２の環状永久磁石と、該第２の磁石の平面
部と密着し、第１及び第２の永久磁石の外径部を
包含して、第１の永久磁石の側面より発生する漏
洩磁束をさえぎるための環状部を有するポールピ
ースを設け、上記ポールピースと軟磁性軸との
間、及び上記第１の永久磁石と軟磁性軸との間に
夫々磁性流体を磁気的に捕捉するように構成した
ことを特徴とする磁性流体シール装置。 a first annular permanent magnet magnetized in the radial direction;
A second annular permanent magnet magnetized in the axial direction separately from or integrally with the first permanent magnet; and a second annular permanent magnet that is in close contact with the flat surface of the second magnet, and that has an outer diameter portion of the first and second permanent magnets. A pole piece including an annular portion for blocking leakage magnetic flux generated from a side surface of the first permanent magnet is provided, and a pole piece is provided between the pole piece and the soft magnetic shaft, and between the first permanent magnet and the soft magnetic shaft. A magnetic fluid sealing device characterized in that it is configured to magnetically trap magnetic fluid between each shaft and a shaft.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19701686U JPH0338521Y2 (en) | 1986-12-22 | 1986-12-22 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19701686U JPH0338521Y2 (en) | 1986-12-22 | 1986-12-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63101367U JPS63101367U (en) | 1988-07-01 |
| JPH0338521Y2 true JPH0338521Y2 (en) | 1991-08-14 |
Family
ID=31156358
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19701686U Expired JPH0338521Y2 (en) | 1986-12-22 | 1986-12-22 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0338521Y2 (en) |
-
1986
- 1986-12-22 JP JP19701686U patent/JPH0338521Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63101367U (en) | 1988-07-01 |
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