JP2007165741A - Permanent magnet unit and magnetic field generator provided therewith - Google Patents

Permanent magnet unit and magnetic field generator provided therewith Download PDF

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JP2007165741A
JP2007165741A JP2005362657A JP2005362657A JP2007165741A JP 2007165741 A JP2007165741 A JP 2007165741A JP 2005362657 A JP2005362657 A JP 2005362657A JP 2005362657 A JP2005362657 A JP 2005362657A JP 2007165741 A JP2007165741 A JP 2007165741A
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permanent magnet
magnetic field
magnet unit
pair
field generator
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Takeshi Tsuzaki
剛 津崎
Masaaki Aoki
雅昭 青木
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Hitachi Metals Ltd
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Neomax Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet unit capable of being constituted at a low cost, and suppressing the decline of magnetic characteristics even while a magnetization direction is practically inclined, and to provide a magnetic field generator provided with it. <P>SOLUTION: The permanent magnet unit 10 is provided with a pair of permanent magnets 12 respectively formed in a cube shape. The magnetization directions A of the pair of permanent magnets 12 are respectively vertical to a surface 14a and a surface 14b, and parallel with a surface 16 other than the surfaces 14a and 14b. The pair of permanent magnets 12 are connected such that the surface 14a of one permanent magnet 12 and the surface 16 of the other permanent magnet 12 are in contact and are magnetically coupled while making the magnetization directions A of each other be different by 90°. Thus, the magnetization directions A of the pair of permanent magnets 12 are combined and the magnetization direction of the permanent magnet unit 10 becomes a practically inclined magnetization direction B. The permanent magnet unit 10 constituted in such a manner is used in the magnetic field generator or the like for an MRI apparatus for instance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

この発明は永久磁石ユニットおよびそれを備える磁界発生装置に関し、より特定的には、表面に対して実質的に傾いた磁化方向を有する永久磁石ユニットおよびそれを備える磁界発生装置に関する。   The present invention relates to a permanent magnet unit and a magnetic field generator including the same, and more particularly to a permanent magnet unit having a magnetization direction substantially inclined with respect to a surface and a magnetic field generator including the same.

一般に、一対の磁極片間の空隙に磁界を発生させる磁界発生装置では、たとえば特許文献１に開示されているように磁極片の環状突起の外側面に漏洩磁束防止用の永久磁石を設けることが知られている。特許文献１には、漏洩磁束防止用の永久磁石として、図１２（ａ）に示すような表面に対して傾いた磁化方向を有する永久磁石１を用いることが開示されている。
特開２００１−３２６１１８ In general, in a magnetic field generator that generates a magnetic field in a gap between a pair of magnetic pole pieces, for example, as disclosed in Patent Document 1, a permanent magnet for preventing leakage magnetic flux is provided on the outer surface of an annular protrusion of the magnetic pole piece. Are known. Patent Document 1 discloses that a permanent magnet 1 having a magnetization direction inclined with respect to the surface as shown in FIG. 12A is used as a permanent magnet for preventing leakage magnetic flux.
JP 2001-326118 A

しかし、永久磁石１を得るためには、特許文献１に開示されているような特殊なプレス装置を用いて磁界中で成形する必要がある。このために、永久磁石１の製造コストが上昇してしまう。また、図１２（ｂ）に示すように、表面に対して垂直あるいは平行な磁化方向を有する永久磁石２から永久磁石１（破線で示す）を切り出すことも可能である。しかし、永久磁石２において永久磁石１以外の部分が無駄となり、歩留まりが悪くなってしまう。したがって、この場合も永久磁石１の製造コストが上昇してしまう。   However, in order to obtain the permanent magnet 1, it is necessary to form it in a magnetic field using a special pressing device as disclosed in Patent Document 1. For this reason, the manufacturing cost of the permanent magnet 1 will rise. Further, as shown in FIG. 12B, it is possible to cut out a permanent magnet 1 (shown by a broken line) from a permanent magnet 2 having a magnetization direction perpendicular or parallel to the surface. However, the portion of the permanent magnet 2 other than the permanent magnet 1 is wasted and the yield is deteriorated. Therefore, also in this case, the manufacturing cost of the permanent magnet 1 increases.

また、永久磁石１の角部｛図１２（ａ）において斜線が入った部分｝では、その内部の反磁界が大きくなるために動作点が低くなり、温度や外部磁界の影響によって不可逆減磁しやすい。つまり、永久磁石１では、磁気特性が低下しやすいという問題があった。   Further, at the corner portion of the permanent magnet 1 (the hatched portion in FIG. 12 (a)), the demagnetizing field inside the permanent magnet 1 becomes large, so the operating point becomes low, and the irreversible demagnetization is caused by the influence of temperature and external magnetic field. Cheap. That is, the permanent magnet 1 has a problem that the magnetic characteristics are likely to deteriorate.

それゆえに、この発明の主たる目的は、磁化方向を実質的に傾けつつも製造コストを抑制できかつ磁気特性の低下を抑制できる永久磁石ユニット、およびそれを備える磁界発生装置を提供することである。   Therefore, a main object of the present invention is to provide a permanent magnet unit that can suppress the manufacturing cost and suppress the deterioration of the magnetic characteristics while substantially tilting the magnetization direction, and a magnetic field generator including the permanent magnet unit.

上述の目的を達成するために、請求項１に記載の永久磁石ユニットは、それぞれ直方体状に形成されかつ表面に対して垂直あるいは平行な磁化方向を有する一対の永久磁石を備え、一対の永久磁石は互いの磁化方向を９０°異ならせて磁気的に結合される。   In order to achieve the above object, the permanent magnet unit according to claim 1 includes a pair of permanent magnets each formed in a rectangular parallelepiped shape and having a magnetization direction perpendicular or parallel to the surface. Are magnetically coupled with their magnetization directions different by 90 °.

請求項２に記載の永久磁石ユニットは、請求項１に記載の永久磁石ユニットにおいて、永久磁石が接触することを特徴とする。   A permanent magnet unit according to a second aspect is the permanent magnet unit according to the first aspect, wherein the permanent magnet is in contact with the permanent magnet unit.

請求項３に記載の永久磁石ユニットは、請求項１に記載の永久磁石ユニットにおいて、非磁性体からなり永久磁石間に介挿される介挿部材をさらに含むことを特徴とする。   A permanent magnet unit according to a third aspect is the permanent magnet unit according to the first aspect, further comprising an insertion member made of a non-magnetic material and interposed between the permanent magnets.

請求項４に記載の永久磁石ユニットは、請求項１から３のいずれかに記載の永久磁石ユニットにおいて、非磁性体からなり一対の永久磁石を跨いで一対の永久磁石に設けられる被覆部材をさらに含むことを特徴とする。   A permanent magnet unit according to a fourth aspect of the present invention is the permanent magnet unit according to any one of the first to third aspects, further comprising a covering member made of a non-magnetic material and provided on the pair of permanent magnets across the pair of permanent magnets. It is characterized by including.

請求項５に記載の磁界発生装置は、請求項１から４のいずれかに記載の永久磁石ユニットを備えることを特徴とする。   A magnetic field generation apparatus according to a fifth aspect includes the permanent magnet unit according to any one of the first to fourth aspects.

請求項６に記載の磁界発生装置は、請求項５に記載の磁界発生装置において、外側面に永久磁石ユニットが設けられる環状突起をそれぞれ有し空隙を介して対向配置される一対の磁極片をさらに含み、永久磁石ユニットの一対の永久磁石は環状突起の径方向に並置され、内側の永久磁石の磁化方向は径方向に向けられかつ外側の永久磁石の磁化方向は環状突起の軸方向に向けられることを特徴とする。   A magnetic field generation device according to a sixth aspect is the magnetic field generation device according to the fifth aspect, in which a pair of magnetic pole pieces each having an annular protrusion provided with a permanent magnet unit on the outer surface and arranged to face each other via a gap are provided. In addition, the pair of permanent magnets of the permanent magnet unit are juxtaposed in the radial direction of the annular projection, the magnetization direction of the inner permanent magnet is directed in the radial direction, and the magnetization direction of the outer permanent magnet is oriented in the axial direction of the annular projection. It is characterized by being able to.

請求項７に記載の磁界発生装置は、請求項６に記載の磁界発生装置において、内側の永久磁石は外側の永久磁石よりも保磁力が大きいことを特徴とする。   The magnetic field generator according to claim 7 is the magnetic field generator according to claim 6, wherein the inner permanent magnet has a larger coercive force than the outer permanent magnet.

請求項１に記載の永久磁石ユニットでは、それぞれ直方体状に形成されかつ表面に対して垂直あるいは平行な磁化方向を有する一対の永久磁石が、互いの磁化方向を９０°異ならせて磁気的に結合される。これによって、一対の永久磁石の磁化方向が合成され、磁化方向を実質的に傾けることができる。このように一対の永久磁石を組み合わせることによって実質的に傾いた磁化方向を得ることができるので、特殊な装置を用いて磁界中で成形する必要がなく、歩留まりを悪化させることもなく、製造コストを抑制できる。また、それぞれ表面に対して垂直あるいは平行な磁化方向を有する一対の永久磁石を組み合わせるので、表面に対して傾いた磁化方向を有する永久磁石に比べて不可逆減磁しにくく、磁気特性の低下を抑制できる。   The permanent magnet unit according to claim 1, wherein a pair of permanent magnets each formed in a rectangular parallelepiped shape and having a magnetization direction perpendicular or parallel to the surface is magnetically coupled with each other having a magnetization direction different by 90 °. Is done. Thereby, the magnetization directions of the pair of permanent magnets are combined, and the magnetization directions can be substantially tilted. Since a substantially tilted magnetization direction can be obtained by combining a pair of permanent magnets in this way, there is no need to form in a magnetic field using a special device, and the production cost is not deteriorated. Can be suppressed. In addition, since a pair of permanent magnets each having a magnetization direction perpendicular or parallel to the surface is combined, irreversible demagnetization is less likely than permanent magnets having a magnetization direction inclined with respect to the surface, and the deterioration of magnetic properties is suppressed. it can.

請求項２に記載の永久磁石ユニットでは、永久磁石が接触することによって、磁気効率が良好になり、それぞれの磁化方向を効率的に合成できる。また、一対の永久磁石のみで構成されるため簡素で低コストに構成できる。   In the permanent magnet unit according to the second aspect, when the permanent magnet comes into contact, the magnetic efficiency is improved, and the respective magnetization directions can be efficiently synthesized. Moreover, since it is comprised only with a pair of permanent magnet, it can comprise simply and at low cost.

請求項３に記載の永久磁石ユニットでは、永久磁石の間に非磁性体からなる介挿部材を介挿することによって、一対の永久磁石の間に生じる反発力を緩和でき、組み立てを容易にできる。また、介挿部材によって一対の永久磁石の間に生じる反発力が緩和されるので、永久磁石を固定するための接着剤等にかかる負荷を小さくでき、接着剤等の剥離を防止できる。   In the permanent magnet unit according to claim 3, by inserting an insertion member made of a non-magnetic material between the permanent magnets, the repulsive force generated between the pair of permanent magnets can be reduced, and the assembly can be facilitated. . Moreover, since the repulsive force which arises between a pair of permanent magnets by the insertion member is relieved, the load concerning the adhesive agent etc. for fixing a permanent magnet can be made small, and peeling of an adhesive agent etc. can be prevented.

請求項４に記載の永久磁石ユニットでは、非磁性体からなる被覆部材を一対の永久磁石を跨いで一対の永久磁石に設けることによって、一対の永久磁石の間の反発力が強力であっても一対の永久磁石を被覆部材によって強固に固定でき、永久磁石の離脱を防止できる。   In the permanent magnet unit according to claim 4, even if the repulsive force between the pair of permanent magnets is strong by providing the covering member made of a non-magnetic material on the pair of permanent magnets across the pair of permanent magnets. The pair of permanent magnets can be firmly fixed by the covering member, and separation of the permanent magnets can be prevented.

請求項５に記載の磁界発生装置では、磁化方向を実質的に傾けつつも製造コストを抑制できる請求項１から４のいずれかに記載の永久磁石ユニットを用いることによって、低コストに構成できる。また、磁化方向を実質的に傾けつつも磁気特性の低下を抑制できる請求項１から４のいずれかに記載の永久磁石ユニットを用いることによって、磁界を安定して発生させることができる。   The magnetic field generator according to claim 5 can be configured at low cost by using the permanent magnet unit according to any one of claims 1 to 4 that can suppress the manufacturing cost while substantially tilting the magnetization direction. Further, by using the permanent magnet unit according to any one of claims 1 to 4, which can suppress a decrease in magnetic characteristics while substantially tilting the magnetization direction, a magnetic field can be stably generated.

請求項６に記載の磁界発生装置では、請求項１から４のいずれかに記載の永久磁石ユニットが漏洩磁束防止用として一対の磁極片の環状突起の外側面にそれぞれ設けられる。永久磁石ユニットの一対の永久磁石は環状突起の径方向に並置され、内側の永久磁石は磁化方向が環状突起の径方向に向けられかつ外側の永久磁石は磁化方向が環状突起の軸方向に向けられる。このように一対の磁極片にそれぞれ永久磁石ユニットを設けることによって、環状突起の外側面からの漏洩磁束を抑制でき、より多くの磁束を空隙に導くことができる。ひいては空隙に発生させる磁界の強度を強くできる。   In the magnetic field generator according to a sixth aspect, the permanent magnet units according to any one of the first to fourth aspects are respectively provided on the outer surfaces of the annular protrusions of the pair of magnetic pole pieces for preventing leakage magnetic flux. The pair of permanent magnets of the permanent magnet unit are juxtaposed in the radial direction of the annular projection, the inner permanent magnet is oriented in the radial direction of the annular projection, and the outer permanent magnet is oriented in the axial direction of the annular projection. It is done. Thus, by providing a permanent magnet unit for each of the pair of magnetic pole pieces, leakage magnetic flux from the outer surface of the annular protrusion can be suppressed, and more magnetic flux can be guided to the gap. As a result, the strength of the magnetic field generated in the air gap can be increased.

請求項７に記載の磁界発生装置では、環状突起の外側面に発生する漏洩磁束の影響を受けやすい内側の永久磁石の保磁力を外側の永久磁石よりも大きくすることによって、内側の永久磁石の減磁を抑えることができ、磁界をより安定して発生させることができる。   In the magnetic field generator according to claim 7, the coercive force of the inner permanent magnet, which is easily affected by the leakage magnetic flux generated on the outer surface of the annular protrusion, is made larger than that of the outer permanent magnet. Demagnetization can be suppressed, and a magnetic field can be generated more stably.

この発明によれば、磁化方向を実質的に傾けつつも製造コストを抑制できかつ磁気特性の低下を抑制できる永久磁石ユニット、およびそれを備える磁界発生装置が得られる。   According to the present invention, it is possible to obtain a permanent magnet unit that can suppress the manufacturing cost and suppress the deterioration of the magnetic characteristics while substantially tilting the magnetization direction, and a magnetic field generator including the permanent magnet unit.

以下、図面を参照して、この発明の実施の形態について説明する。
図１および図２を参照して、この発明の一実施形態の永久磁石ユニット１０は、同寸法の直方体状（ここでは立方体状）に形成される一対の永久磁石１２を備える。 Embodiments of the present invention will be described below with reference to the drawings.
1 and 2, a permanent magnet unit 10 according to an embodiment of the present invention includes a pair of permanent magnets 12 formed in a rectangular parallelepiped shape (here, a cubic shape) having the same dimensions.

一対の永久磁石１２はそれぞれ、表面に対して垂直あるいは平行な磁化方向Ａを有する。以下、磁化方向Ａに垂直でありかつ磁化方向Ａの終端側の表面を表面１４ａといい、磁化方向Ａに垂直でありかつ磁化方向Ａの始端側の表面を表面１４ｂという。また、磁化方向Ａに平行な表面（表面１４ａ，１４ｂ以外の表面）を表面１６という。   Each of the pair of permanent magnets 12 has a magnetization direction A perpendicular or parallel to the surface. Hereinafter, the surface perpendicular to the magnetization direction A and on the terminal side of the magnetization direction A is referred to as a surface 14a, and the surface perpendicular to the magnetization direction A and on the start end side in the magnetization direction A is referred to as a surface 14b. A surface parallel to the magnetization direction A (a surface other than the surfaces 14a and 14b) is referred to as a surface 16.

一対の永久磁石１２は、一方の永久磁石１２の表面１４ａと他方の永久磁石１２の表面１６とが接触するように、接着剤等を用いて連結される。したがって、図２に示すように、一対の永久磁石１２は互いの磁化方向Ａを９０°異ならせて磁気的に結合される。   The pair of permanent magnets 12 are connected using an adhesive or the like so that the surface 14a of one permanent magnet 12 and the surface 16 of the other permanent magnet 12 are in contact with each other. Therefore, as shown in FIG. 2, the pair of permanent magnets 12 are magnetically coupled with their magnetization directions A different by 90 °.

このように構成される永久磁石ユニット１０では、一対の永久磁石１２の磁化方向Ａが合成され、磁化方向が実質的に図２に一点鎖線で示すＢとなる。図２においては、左側の永久磁石１２の磁化方向Ａが右向きでありかつ右側の永久磁石１２の磁化方向Ａが上向きであるので、永久磁石ユニット１０の磁化方向Ｂは実質的に右斜め上に傾くこととなる。   In the permanent magnet unit 10 configured as described above, the magnetization directions A of the pair of permanent magnets 12 are combined, and the magnetization direction is substantially B indicated by a one-dot chain line in FIG. In FIG. 2, since the magnetization direction A of the left permanent magnet 12 is rightward and the magnetization direction A of the right permanent magnet 12 is upward, the magnetization direction B of the permanent magnet unit 10 is substantially diagonally upward to the right. It will tilt.

このような永久磁石ユニット１０によれば、一対の永久磁石１２を組み合わせることによって実質的に傾いた磁化方向Ｂを得ることができるので、特殊な装置を用いて磁界中で成形する必要がなく、歩留まりを悪化させることもなく、製造コストを抑制できる。   According to such a permanent magnet unit 10, since a substantially inclined magnetization direction B can be obtained by combining a pair of permanent magnets 12, there is no need to form in a magnetic field using a special device, The manufacturing cost can be suppressed without deteriorating the yield.

また、永久磁石ユニット１０では、それぞれ磁化方向Ａを有する一対の永久磁石１２を組み合わせることで実質的に傾いた磁化方向Ｂを得るので、図１２（ａ）に示すような永久磁石１に比べて不可逆減磁しにくく、磁気特性の低下を抑制できる。   Further, in the permanent magnet unit 10, a substantially tilted magnetization direction B is obtained by combining a pair of permanent magnets 12 each having a magnetization direction A. Therefore, compared to the permanent magnet 1 as shown in FIG. It is difficult to irreversibly demagnetize, and a decrease in magnetic properties can be suppressed.

さらに、永久磁石ユニット１０では、永久磁石１２が接触することによって、磁気効率が良好になり、それぞれの磁化方向Ａを効率的に合成して磁化方向Ｂを得ることができる。また、一対の永久磁石１２のみで構成されるため簡素で低コストに構成できる。   Further, in the permanent magnet unit 10, the permanent magnet 12 comes into contact with each other, so that the magnetic efficiency is improved, and the magnetization directions B can be obtained by efficiently combining the magnetization directions A. Moreover, since it is comprised only with a pair of permanent magnet 12, it can comprise simply and at low cost.

なお、一対の永久磁石１２の連結態様は、永久磁石ユニット１０に限定されない。たとえば、図３に示す永久磁石ユニット１０ａのように、一方の永久磁石１２の表面１６と他方の永久磁石１２の表面１４ｂとが接触するように一対の永久磁石１２を連結してもよい。この場合も永久磁石ユニット１０と同様に、実質的に傾いた磁化方向Ｂを得ることができる。   The connection mode of the pair of permanent magnets 12 is not limited to the permanent magnet unit 10. For example, a pair of permanent magnets 12 may be coupled such that the surface 16 of one permanent magnet 12 and the surface 14b of the other permanent magnet 12 are in contact with each other as in the permanent magnet unit 10a shown in FIG. In this case as well, as with the permanent magnet unit 10, a substantially tilted magnetization direction B can be obtained.

また、図４に示す永久磁石ユニット１０ｂのように、一方の永久磁石１２の表面１４ａと、他方の永久磁石１２の表面１６との間にアルミニウムやステンレス等の非磁性体からなる介挿部材１８を介挿してもよい。このような永久磁石ユニット１０ｂによれば、介挿部材１８によって一対の永久磁石１２の間に生じる反発力を緩和でき、組み立てを容易にできる。また、介挿部材１８によって一対の永久磁石１２の間に生じる反発力が緩和されるので、永久磁石１２を固定するための接着剤等にかかる負荷を小さくでき、接着剤等の剥離を防止できる。   Moreover, like the permanent magnet unit 10b shown in FIG. 4, the insertion member 18 which consists of nonmagnetic materials, such as aluminum and stainless steel, between the surface 14a of one permanent magnet 12, and the surface 16 of the other permanent magnet 12 is used. May be inserted. According to such a permanent magnet unit 10b, the repulsive force which arises between a pair of permanent magnets 12 by the insertion member 18 can be relieved, and an assembly can be made easy. Further, since the repulsive force generated between the pair of permanent magnets 12 is alleviated by the interposing member 18, the load applied to the adhesive or the like for fixing the permanent magnet 12 can be reduced, and peeling of the adhesive or the like can be prevented. .

また、図５（ａ）に示す永久磁石ユニット１０ｃのように、一対の永久磁石１２の面一な表面を跨ぐように、アルミニウムやステンレス等の非磁性体からなる被覆部材１９を一対の永久磁石１２に設けてもよい。このように被覆部材１９を設けることによって、一対の永久磁石１２の間の反発力が強力であっても一対の永久磁石１２を被覆部材１９に強固に固定でき、永久磁石１２の離脱を防止できる。   Moreover, like the permanent magnet unit 10c shown to Fig.5 (a), the covering member 19 which consists of nonmagnetic materials, such as aluminum and stainless steel, is straddled across the flush surface of a pair of permanent magnet 12, A pair of permanent magnet 12 may be provided. By providing the covering member 19 in this manner, even if the repulsive force between the pair of permanent magnets 12 is strong, the pair of permanent magnets 12 can be firmly fixed to the covering member 19 and the separation of the permanent magnets 12 can be prevented. .

さらに、図５（ｂ）に示す永久磁石ユニット１０ｄのように、一対の永久磁石１２の表面全てを被覆するように被覆部材１９ａを設けてもよい。このように被覆部材１９ａを設けることによって、一対の永久磁石１２の割れや欠けを防止できる。   Furthermore, a covering member 19a may be provided so as to cover the entire surface of the pair of permanent magnets 12 as in the permanent magnet unit 10d shown in FIG. Thus, by providing the covering member 19a, it is possible to prevent the pair of permanent magnets 12 from being cracked or chipped.

また、一対の永久磁石を備える永久磁石ユニットを複数組み合わせて永久磁石ユニットを構成してもよい。たとえば図６（ａ）に示す永久磁石ユニット２０のように、２つの永久磁石ユニット１０を、互いの隣接する永久磁石１２の磁化方向Ａが同方向になるように連結してもよい。また、図６（ｂ）に示す永久磁石ユニット２０ａのように、永久磁石ユニット１０，１０ａを、互いの隣接する永久磁石１２の磁化方向Ａを９０°異ならせて連結してもよい。これらの場合も実質的に傾いた磁化方向Ｂを得ることができる。   Moreover, you may comprise a permanent magnet unit combining several permanent magnet units provided with a pair of permanent magnet. For example, like the permanent magnet unit 20 shown to Fig.6 (a), you may connect the two permanent magnet units 10 so that the magnetization direction A of the mutually adjacent permanent magnet 12 may become the same direction. Further, like the permanent magnet unit 20a shown in FIG. 6B, the permanent magnet units 10 and 10a may be connected with the magnetization directions A of the adjacent permanent magnets 12 different from each other by 90 °. Also in these cases, a substantially tilted magnetization direction B can be obtained.

さらに、図７に示すように、永久磁石ユニット１０と、表面に対して垂直あるいは平行な磁化方向Ａ１を有する永久磁石１３とを用いて永久磁石ユニット３０を構成してもよい。永久磁石ユニット３０では、永久磁石１３の磁化方向Ａ１が一対の永久磁石１２それぞれの磁化方向Ａに対して９０°異なるように、永久磁石１３が一対の永久磁石１２上に配置される。このような永久磁石ユニット３０では、実質的に三次元的に傾いた磁化方向Ｃを得ることができる。   Furthermore, as shown in FIG. 7, the permanent magnet unit 30 may be configured using the permanent magnet unit 10 and the permanent magnet 13 having a magnetization direction A1 perpendicular or parallel to the surface. In the permanent magnet unit 30, the permanent magnet 13 is disposed on the pair of permanent magnets 12 so that the magnetization direction A1 of the permanent magnet 13 differs by 90 ° with respect to the magnetization direction A of the pair of permanent magnets 12. In such a permanent magnet unit 30, a magnetization direction C tilted substantially three-dimensionally can be obtained.

磁化方向Ｂの傾き（磁化角度θ：図２参照）は任意に設定できる。図２をみて、たとえば、左側の永久磁石１２の厚みＴを小さくするあるいは右側の永久磁石１２の厚みＴを大きくすることによって、永久磁石ユニット１０の磁化角度θは大きくなる。また、たとえば、左側の永久磁石１２の厚みＴを大きくするあるいは右側の永久磁石１２の厚みＴを小さくすることによって、永久磁石ユニット１０の磁化角度θは小さくなる。また、一対の永久磁石１２において互いの磁気特性を変更することによっても永久磁石ユニット１０の磁化角度θを変更できる。   The inclination of the magnetization direction B (magnetization angle θ: see FIG. 2) can be set arbitrarily. Referring to FIG. 2, for example, by decreasing the thickness T of the left permanent magnet 12 or increasing the thickness T of the right permanent magnet 12, the magnetization angle θ of the permanent magnet unit 10 increases. Further, for example, by increasing the thickness T of the left permanent magnet 12 or decreasing the thickness T of the right permanent magnet 12, the magnetization angle θ of the permanent magnet unit 10 is decreased. Also, the magnetization angle θ of the permanent magnet unit 10 can be changed by changing the magnetic characteristics of the pair of permanent magnets 12.

なお、永久磁石１２，１３は、１つの永久磁石によって構成してもよいし、複数の磁石単体を積層することによって構成してもよい。   The permanent magnets 12 and 13 may be constituted by one permanent magnet or may be constituted by laminating a plurality of single magnets.

ついで、図８を参照して、この発明の永久磁石ユニットを備える磁界発生装置１００について説明する。磁界発生装置１００は、オープンタイプの磁界発生装置であり、たとえばＭＲＩ装置等に用いられる。   Next, with reference to FIG. 8, a magnetic field generator 100 including the permanent magnet unit of the present invention will be described. The magnetic field generator 100 is an open type magnetic field generator, and is used for an MRI apparatus, for example.

磁界発生装置１００は、空隙Ｓ１を介して対向配置される一対の磁極ユニット１０２ａおよび１０２ｂを含む。磁極ユニット１０２ａと１０２ｂとは、図示しない継鉄によって連結され磁気的に結合される。   The magnetic field generation device 100 includes a pair of magnetic pole units 102a and 102b that are arranged to face each other via a gap S1. The magnetic pole units 102a and 102b are connected and magnetically coupled by a yoke (not shown).

磁極ユニット１０２ａおよび１０２ｂはそれぞれ板状継鉄１０４ａおよび１０４ｂを含む。板状継鉄１０４ａおよび１０４ｂのそれぞれの対向面側には、永久磁石群１０６ａおよび１０６ｂが配置され、永久磁石群１０６ａおよび１０６ｂのそれぞれの対向面側には、磁極片１０８ａおよび１０８ｂが固着される。   The magnetic pole units 102a and 102b include plate yokes 104a and 104b, respectively. Permanent magnet groups 106a and 106b are arranged on the opposing surface sides of the plate yokes 104a and 104b, and magnetic pole pieces 108a and 108b are fixed to the opposing surface sides of the permanent magnet groups 106a and 106b. .

永久磁石群１０６ａおよび１０６ｂはそれぞれ、たとえばＲ−Ｆｅ−Ｂ系焼結磁石からなる複数の磁石単体１１０を含み、磁石単体１１０を３段に重ねて形成される。   Each of the permanent magnet groups 106a and 106b includes a plurality of magnet units 110 made of, for example, an R—Fe—B based sintered magnet, and is formed by stacking the magnet units 110 in three stages.

磁極片１０８ａは、永久磁石群１０６ａの主面に配置されるたとえば鉄からなる円板状のベースプレート１１２を含む。ベースプレート１１２の主面には、うず電流の発生を防止するための珪素鋼板１１４が形成される。珪素鋼板１１４は、ベースプレート１１２上に接着剤で固定される。   The pole piece 108a includes a disk-shaped base plate 112 made of, for example, iron and disposed on the main surface of the permanent magnet group 106a. A silicon steel plate 114 for preventing generation of eddy current is formed on the main surface of the base plate 112. The silicon steel plate 114 is fixed on the base plate 112 with an adhesive.

ベースプレート１１２の周縁部には、たとえば鉄からなり周縁部の磁界強度を上げるための環状突起１１６が設けられる。環状突起１１６は、図９に示すように、複数（ここでは８つ）の環状突起片１１８を含む。各環状突起片１１８は、その内側面が円弧状に湾曲されかつ外側面が平面状に形成される。環状突起１１６は、各環状突起片１１８を珪素鋼板１１４の周縁部に図示しないねじ等で固定することによって設けられる。   An annular projection 116 made of, for example, iron and used to increase the magnetic field strength of the peripheral portion is provided on the peripheral portion of the base plate 112. As shown in FIG. 9, the annular protrusion 116 includes a plurality (eight in this case) of annular protrusions 118. Each annular projection piece 118 has an inner surface curved in an arc shape and an outer surface formed in a flat shape. The annular protrusion 116 is provided by fixing each annular protrusion 118 to the peripheral edge of the silicon steel plate 114 with a screw (not shown) or the like.

図８に示すように、磁極片１０８ａの環状突起１１６の外側面には、漏洩磁束防止用の永久磁石ユニット１０ｅが設けられ、磁極片１０８ｂの環状突起１１６の外側面には、漏洩磁束防止用の永久磁石ユニット１０ｆが設けられる。図９に示すように、永久磁石ユニット１０ｅは、各環状突起片１１８に対応して環状突起１１６の外側面に複数（ここでは８つ）設けられる。永久磁石ユニット１０ｆについても同様である。   As shown in FIG. 8, a permanent magnet unit 10e for preventing leakage magnetic flux is provided on the outer surface of the annular protrusion 116 of the magnetic pole piece 108a, and for preventing leakage magnetic flux on the outer surface of the annular protrusion 116 of the magnetic pole piece 108b. The permanent magnet unit 10f is provided. As shown in FIG. 9, a plurality (eight in this case) of permanent magnet units 10 e are provided on the outer surface of the annular protrusion 116 corresponding to each annular protrusion piece 118. The same applies to the permanent magnet unit 10f.

永久磁石ユニット１０ｅおよび１０ｆはそれぞれ、直方体状に形成され、同寸法の一対の永久磁石１２ａ，１２ｂを備える。永久磁石１２ａ，１２ｂはそれぞれ、表面が長方形状に形成され表面に対して垂直あるいは平行な磁化方向Ａを有する。   Each of the permanent magnet units 10e and 10f is formed in a rectangular parallelepiped shape and includes a pair of permanent magnets 12a and 12b having the same dimensions. Each of the permanent magnets 12a and 12b is formed in a rectangular shape and has a magnetization direction A that is perpendicular or parallel to the surface.

なお、永久磁石１２ａ，１２ｂはそれぞれ、たとえばＲ−Ｆｅ−Ｂ系焼結磁石からなる複数の磁石単体によって構成されてもよい。   In addition, each of the permanent magnets 12a and 12b may be constituted by a plurality of single magnets made of, for example, an R—Fe—B based sintered magnet.

図８に示すように、永久磁石ユニット１０ｅの永久磁石１２ａと１２ｂとは、図１および図２に示す永久磁石ユニット１０の一対の永久磁石１２と同様に連結される。永久磁石ユニット１０ｅの永久磁石１２ａと１２ｂとは、永久磁石１２ａが内側（環状突起１１６側）に位置し永久磁石１２ｂが外側に位置するように、環状突起１１６の径方向（矢印Ｘ方向）に並置される。永久磁石ユニット１０ｅにおいて、永久磁石１２ａの磁化方向Ａは矢印Ｘ方向かつ永久磁石１２ｂ側に向けられ、永久磁石１２ｂの磁化方向Ａは環状突起１１６の軸方向（矢印Ｙ方向）かつ上側に向けられる。   As shown in FIG. 8, the permanent magnets 12a and 12b of the permanent magnet unit 10e are coupled in the same manner as the pair of permanent magnets 12 of the permanent magnet unit 10 shown in FIGS. The permanent magnets 12a and 12b of the permanent magnet unit 10e are arranged in the radial direction (arrow X direction) of the annular projection 116 so that the permanent magnet 12a is located on the inner side (annular projection 116 side) and the permanent magnet 12b is located on the outer side. Juxtaposed. In the permanent magnet unit 10e, the magnetization direction A of the permanent magnet 12a is directed to the arrow X direction and the permanent magnet 12b side, and the magnetization direction A of the permanent magnet 12b is directed to the axial direction (arrow Y direction) and the upper side of the annular protrusion 116. .

また、永久磁石ユニット１０ｆの永久磁石１２ａと１２ｂとは、図３に示す永久磁石ユニット１０ａの一対の永久磁石１２と同様に連結される。永久磁石ユニット１０ｆの永久磁石１２ａと１２ｂとは、永久磁石ユニット１０ｅと同様に矢印Ｘ方向に並置される。永久磁石ユニット１０ｆにおいて、永久磁石１２ａの磁化方向Ａは矢印Ｘ方向かつ環状突起１１６側に向けられ、永久磁石１２ｂの磁化方向Ａは矢印Ｙ方向かつ上側に向けられる。   Further, the permanent magnets 12a and 12b of the permanent magnet unit 10f are coupled in the same manner as the pair of permanent magnets 12 of the permanent magnet unit 10a shown in FIG. The permanent magnets 12a and 12b of the permanent magnet unit 10f are juxtaposed in the direction of the arrow X in the same manner as the permanent magnet unit 10e. In the permanent magnet unit 10f, the magnetization direction A of the permanent magnet 12a is directed to the arrow X direction and the annular protrusion 116 side, and the magnetization direction A of the permanent magnet 12b is directed to the arrow Y direction and upward.

したがって、永久磁石ユニット１０ｅの磁化方向Ｂは実質的に環状突起１１６から離れるように斜め上に傾き、永久磁石ユニット１０ｆの磁化方向Ｂは実質的に環状突起１１６に向かうように斜め上に傾く。このように永久磁石ユニット１０ｅと１０ｆとが実質的に傾いた磁化方向Ｂを有することによって、空隙Ｓ１により多くの磁束を導くことができ、空隙Ｓ１の磁界強度を強くできる。   Accordingly, the magnetization direction B of the permanent magnet unit 10 e is inclined obliquely upward so as to be substantially away from the annular protrusion 116, and the magnetization direction B of the permanent magnet unit 10 f is inclined obliquely upward substantially toward the annular protrusion 116. As described above, since the permanent magnet units 10e and 10f have the substantially inclined magnetization direction B, more magnetic flux can be guided to the air gap S1, and the magnetic field strength of the air gap S1 can be increased.

永久磁石１２ａとしては複数の磁石単体を積層してなる高保磁力タイプのＲ−Ｆｅ−Ｂ系焼結磁石が用いられる。また、永久磁石１２ｂとしては複数の磁石単体を積層してなる高残留磁束密度タイプのＲ−Ｆｅ−Ｂ系焼結磁石が用いられる。   As the permanent magnet 12a, a high coercive force type R—Fe—B sintered magnet formed by laminating a plurality of magnets is used. Further, as the permanent magnet 12b, a high residual magnetic flux density type R—Fe—B sintered magnet formed by laminating a plurality of magnets is used.

このような磁界発生装置１００によれば、磁化方向Ｂを有しつつも製造コストを抑制できる永久磁石ユニット１０ｅおよび１０ｆを用いることによって、表面に対して傾いた磁化方向を有する永久磁石を用いる場合に比べて低コストに構成できる。   According to such a magnetic field generation device 100, by using the permanent magnet units 10e and 10f that have the magnetization direction B and can suppress the manufacturing cost, the permanent magnet having the magnetization direction inclined with respect to the surface is used. Compared to, it can be configured at a low cost.

上述のように永久磁石ユニット１０ｅおよび１０ｆを磁極片１０８ａおよび１０８ｂの環状突起１１６の外側面に設けることによって、環状突起１１６の外側面からの漏洩磁束を抑制できる。これによって空隙Ｓ１により多くの磁束を導くことができ、空隙Ｓ１に発生させる磁界の強度を強くできる。   As described above, by providing the permanent magnet units 10e and 10f on the outer surface of the annular protrusion 116 of the magnetic pole pieces 108a and 108b, leakage magnetic flux from the outer surface of the annular protrusion 116 can be suppressed. As a result, more magnetic flux can be guided to the air gap S1, and the strength of the magnetic field generated in the air gap S1 can be increased.

また、環状突起１１６に発生する漏洩磁束の影響を受けやすい永久磁石１２ａの保磁力を永久磁石１２ｂよりも大きくしかつ永久磁石１２ｂの残留磁束密度を永久磁石１２ａよりも大きくすることによって、減磁を抑制し、空隙Ｓ１に磁界をより安定して発生させることができる。   Further, demagnetization is achieved by making the coercive force of the permanent magnet 12a susceptible to the influence of the leakage magnetic flux generated in the annular projection 116 larger than that of the permanent magnet 12b and making the residual magnetic flux density of the permanent magnet 12b larger than that of the permanent magnet 12a. And the magnetic field can be generated more stably in the air gap S1.

ついで、表１を参照して、永久磁石の総重量およびその準備に必要な永久磁石の総重量について、磁界発生装置１００と、従来技術の磁界発生装置と、従来技術の他の磁界発生装置との比較例について説明する。   Next, referring to Table 1, regarding the total weight of the permanent magnets and the total weight of the permanent magnets necessary for the preparation, the magnetic field generator 100, the prior art magnetic field generator, and the other prior art magnetic field generators A comparative example will be described.

従来技術の磁界発生装置は、表面に対して垂直あるいは平行な磁化方向を有する永久磁石を永久磁石ユニット１０ｅおよび１０ｆに代えて漏洩磁束防止用に備えるものである。従来技術の磁界発生装置において、永久磁石ユニット１０ｅに代えて設けられる永久磁石の磁化方向は矢印Ｘ方向かつ環状突起１１６の反対側に向けられ、永久磁石ユニット１０ｆに代えて設けられる永久磁石の磁化方向は矢印Ｘ方向かつ環状突起１１６側に向けられる（図８参照）。また、従来技術の他の磁界発生装置は、表面に対して傾いた磁化方向を有する永久磁石を永久磁石ユニット１０ｅおよび１０ｆに代えて漏洩磁束防止用に備えるものである。従来技術の他の磁界発生装置において、永久磁石ユニット１０ｅおよび１０ｆに代えて設けられる永久磁石の磁化方向は、永久磁石ユニット１０ｅおよび１０ｆの実質的な磁化方向Ｂと同様である。   The prior art magnetic field generator is provided with a permanent magnet having a magnetization direction perpendicular or parallel to the surface to prevent leakage magnetic flux instead of the permanent magnet units 10e and 10f. In the conventional magnetic field generator, the magnetization direction of the permanent magnet provided in place of the permanent magnet unit 10e is directed in the direction of the arrow X and opposite to the annular protrusion 116, and the magnetization of the permanent magnet provided in place of the permanent magnet unit 10f. The direction is directed in the direction of the arrow X and toward the annular protrusion 116 (see FIG. 8). Another conventional magnetic field generator includes a permanent magnet having a magnetization direction inclined with respect to the surface for preventing leakage magnetic flux instead of the permanent magnet units 10e and 10f. In another conventional magnetic field generator, the magnetization direction of the permanent magnet provided in place of the permanent magnet units 10e and 10f is the same as the substantial magnetization direction B of the permanent magnet units 10e and 10f.

なお、いずれの磁界発生装置も空隙Ｓ１の均一磁界空間（図８において一点鎖線で示す）に０．３Ｔの磁界を発生させるように構成した。また、従来技術の他の磁界発生装置の傾いた磁化方向を有する永久磁石は、表面に対して垂直あるいは平行な磁化方向を有する永久磁石から切り出したものを用いた。   All the magnetic field generators were configured to generate a magnetic field of 0.3 T in a uniform magnetic field space (shown by a one-dot chain line in FIG. 8) of the air gap S1. In addition, the permanent magnet having a tilted magnetization direction of another magnetic field generator of the prior art was cut from a permanent magnet having a magnetization direction perpendicular or parallel to the surface.

Figure 2007165741
Figure 2007165741

磁界発生装置１００と従来技術の磁界発生装置とを比較して、磁界発生装置１００では、永久磁石ユニット１０ｅおよび１０ｆを用いることによってより多くの磁束を空隙Ｓ１に導くことができるので、従来技術の磁界発生装置に比べて漏洩磁束防止用の永久磁石の量を抑えることができ、永久磁石の総重量を小さくできることがわかる。ひいては、低コストに構成できることがわかる。   Compared with the magnetic field generator 100 and the prior art magnetic field generator, the magnetic field generator 100 can guide more magnetic flux to the air gap S1 by using the permanent magnet units 10e and 10f. It can be seen that the amount of permanent magnets for preventing leakage magnetic flux can be reduced as compared with the magnetic field generator, and the total weight of the permanent magnets can be reduced. As a result, it turns out that it can comprise at low cost.

また、磁界発生装置１００と従来技術の他の磁界発生装置とを比較して、従来技術の他の磁界発生装置では磁界発生装置１００よりもさらに永久磁石の総重量が小さくなっている。しかし、従来技術の他の磁界発生装置では、切り出すことによって得た永久磁石を用いるために、準備に必要な永久磁石の総重量が磁界発生装置１００よりも大きくなっている。このことから、磁界発生装置１００では、従来技術の他の磁界発生装置よりも低コストに構成できることがわかる。   Further, comparing the magnetic field generator 100 with another magnetic field generator of the prior art, the total weight of the permanent magnet is smaller in the other magnetic field generator of the prior art than that of the magnetic field generator 100. However, in other magnetic field generators of the prior art, since the permanent magnet obtained by cutting out is used, the total weight of the permanent magnets necessary for preparation is larger than that of the magnetic field generator 100. From this, it can be seen that the magnetic field generator 100 can be configured at a lower cost than other magnetic field generators of the prior art.

このように、磁界発生装置１００では、永久磁石ユニット１０ｅおよび１０ｆを用いることによって、永久磁石の量あるいはその準備に必要な永久磁石の量を従来よりも削減でき、低コストに構成できることがわかる。   Thus, in the magnetic field generator 100, by using the permanent magnet units 10e and 10f, it can be seen that the amount of permanent magnets or the amount of permanent magnets necessary for the preparation can be reduced as compared with the conventional case, and can be configured at low cost.

ついで、図１０を参照して、この発明の永久磁石ユニットを備える他の磁界発生装置２００について説明する。磁界発生装置２００は、２Ｔ以上の磁界を発生させる強磁界タイプの磁界発生装置であり直方体状に形成される。磁界発生装置２００は、たとえば、材料物性研究、磁気分離、磁気冷凍等の装置に用いられる。   Next, with reference to FIG. 10, another magnetic field generation apparatus 200 including the permanent magnet unit of the present invention will be described. The magnetic field generator 200 is a strong magnetic field type magnetic field generator that generates a magnetic field of 2T or more, and is formed in a rectangular parallelepiped shape. The magnetic field generator 200 is used for, for example, materials physical property research, magnetic separation, magnetic refrigeration and the like.

磁界発生装置２００は、対向配置される磁極ユニット２０２ａおよび２０２ｂを含む。磁極ユニット２０２ａは、ポールピース２０４と永久磁石ユニット２０ｂと永久磁石２０６とを含む。   Magnetic field generation device 200 includes magnetic pole units 202a and 202b arranged to face each other. The magnetic pole unit 202a includes a pole piece 204, a permanent magnet unit 20b, and a permanent magnet 206.

ポールピース２０４は、たとえば、鉄からなり、角柱状に形成される。永久磁石ユニット２０ｂはポールピース２０４の各角部に対応して４つ設けられる。   The pole piece 204 is made of, for example, iron and is formed in a prismatic shape. Four permanent magnet units 20b are provided corresponding to each corner of the pole piece 204.

各永久磁石ユニット２０ｂは、図６（ａ）に示す永久磁石ユニット２０と同様に構成され、一対の永久磁石をそれぞれ備える２つの永久磁石ユニットを組み合わせることによって構成される。したがって、永久磁石ユニット２０ｂは、実質的に傾いた磁化方向Ｂを有する。永久磁石２０６は、板状に形成され、各永久磁石ユニット２０ｂ間に介挿される。   Each permanent magnet unit 20b is configured similarly to the permanent magnet unit 20 shown in FIG. 6A, and is configured by combining two permanent magnet units each including a pair of permanent magnets. Therefore, the permanent magnet unit 20b has a substantially inclined magnetization direction B. The permanent magnet 206 is formed in a plate shape and is inserted between the permanent magnet units 20b.

図１１（ａ）に示すように、磁極ユニット２０２ａでは、各永久磁石ユニット２０ｂおよび各永久磁石２０６の磁化方向がポールピース２０４を向くように配置される。したがって、磁極ユニット２０２ａの磁化方向は、ポールピース２０４に集中する方向となる。   As shown in FIG. 11A, in the magnetic pole unit 202a, the permanent magnet units 20b and the permanent magnets 206 are arranged so that the magnetization directions thereof face the pole pieces 204. Therefore, the magnetization direction of the magnetic pole unit 202 a is a direction concentrated on the pole piece 204.

磁極ユニット２０２ｂは、磁化方向を除いて磁極ユニット２０２ａと同様に構成される。図１１（ｂ）に示すように、磁極ユニット２０２ｂでは、各永久磁石ユニット２０ｂおよび各永久磁石２０６の磁化方向が、磁極ユニット２０２ａの各永久磁石ユニット２０ｂおよび各永久磁石２０６の磁化方向と正反対である。したがって、磁極ユニット２０２ｂの磁化方向は、ポールピース２０４から放射する方向となる。   The magnetic pole unit 202b is configured similarly to the magnetic pole unit 202a except for the magnetization direction. As shown in FIG. 11B, in the magnetic pole unit 202b, the magnetization directions of the permanent magnet units 20b and the permanent magnets 206 are opposite to the magnetization directions of the permanent magnet units 20b and the permanent magnets 206 of the magnetic pole unit 202a. is there. Therefore, the magnetization direction of the magnetic pole unit 202b is a direction radiating from the pole piece 204.

また、磁極ユニット２０２ａと２０２ｂとの対向面間には、板状の永久磁石２０８が２つ介挿される。２つの永久磁石２０８は、磁極ユニット２０２ａおよび２０２ｂ間において水平方向に貫通する空隙Ｓ２を形成できるように配置される。各永久磁石２０８の磁化方向（図示せず）は、下（磁極ユニット２０２ｂ）から上（磁極ユニット２０２ａ）に向かう方向である。   Two plate-like permanent magnets 208 are inserted between the opposing surfaces of the magnetic pole units 202a and 202b. The two permanent magnets 208 are arranged so that a gap S2 penetrating in the horizontal direction can be formed between the magnetic pole units 202a and 202b. The magnetization direction (not shown) of each permanent magnet 208 is a direction from the bottom (magnetic pole unit 202b) to the top (magnetic pole unit 202a).

図１０には図示しないが、磁極ユニット２０２ａ，２０２ｂおよび永久磁石２０８の外側面に継鉄を設けてもよい。   Although not shown in FIG. 10, yokes may be provided on the outer surfaces of the magnetic pole units 202 a and 202 b and the permanent magnet 208.

磁極ユニット２０２ａおよび２０２ｂの永久磁石としては、たとえばＮＥＯＭＡＸ−３２ＥＨ（ＮＥＯＭＡＸ社製）が用いられる。また、永久磁石２０８としては、たとえばＮＥＯＭＡＸ−５０（ＮＥＯＭＡＸ社製）が用いられる。   As the permanent magnets of the magnetic pole units 202a and 202b, for example, NEOMAX-32EH (manufactured by NEOMAX) is used. As the permanent magnet 208, for example, NEOMAX-50 (manufactured by NEOMAX) is used.

磁界発生装置１００と同様に、このような磁界発生装置２００によれば、永久磁石ユニット２０ｂを用いることによって、表面に対して傾いた磁化方向を有する永久磁石を用いる場合に比べて低コストに構成できかつ空隙Ｓ２に磁界を安定して発生させることができる。   Similar to the magnetic field generator 100, such a magnetic field generator 200 is configured at a lower cost by using the permanent magnet unit 20b than when using a permanent magnet having a magnetization direction inclined with respect to the surface. And a magnetic field can be stably generated in the air gap S2.

なお、永久磁石ユニット２０ｂに代えて、図６（ｂ）に示す永久磁石ユニット２０ａと同様に構成される永久磁石ユニットを磁界発生装置２００に用いてもよい。   Instead of the permanent magnet unit 20b, a permanent magnet unit configured similarly to the permanent magnet unit 20a shown in FIG. 6B may be used for the magnetic field generator 200.

ついで、表２を参照して、永久磁石の総重量およびその準備に必要な永久磁石の総重量について、磁界発生装置２００と、従来技術の磁界発生装置と、従来技術の他の磁界発生装置との比較例について説明する。   Next, referring to Table 2, regarding the total weight of the permanent magnets and the total weight of the permanent magnets required for the preparation, the magnetic field generator 200, the prior art magnetic field generator, and the other prior art magnetic field generators A comparative example will be described.

ここでの従来技術の磁界発生装置は、表面に対して垂直あるいは平行な磁化方向を有する永久磁石を永久磁石ユニット２０ｂに代えて備えるものである。図１１（ａ）を参照して、磁極ユニット２０２ａにおいて、左上および左下の永久磁石ユニット２０ｂに代えて設けられる永久磁石の磁化方向はそれぞれ右向きであり、右上および右下の永久磁石ユニット２０ｂに代えて設けられる永久磁石の磁化方向はそれぞれ左向きである。また、図１１（ｂ）を参照して、磁極ユニット２０２ｂにおいて、左上および左下の永久磁石ユニット２０ｂに代えて設けられる永久磁石の磁化方向はそれぞれ左向きであり、右上および右下の永久磁石ユニット２０ｂに代えて設けられる永久磁石の磁化方向はそれぞれ右向きである。また、ここでの従来技術の他の磁界発生装置は、表面に対して傾いた磁化方向を有する永久磁石を永久磁石ユニット２０ｂに代えて備えるものである。従来技術の他の磁界発生装置において、永久磁石ユニット２０ｂに代えて設けられる永久磁石の磁化方向は、永久磁石ユニット２０ｂの実質的な磁化方向Ｂと同様である。   The conventional magnetic field generation apparatus here includes a permanent magnet having a magnetization direction perpendicular or parallel to the surface in place of the permanent magnet unit 20b. Referring to FIG. 11A, in the magnetic pole unit 202a, the magnetization directions of the permanent magnets provided in place of the upper left and lower left permanent magnet units 20b are rightward, respectively, and are replaced by the upper right and lower right permanent magnet units 20b. The direction of magnetization of the permanent magnets provided in the left direction is the left direction. Referring to FIG. 11B, in the magnetic pole unit 202b, the magnetization directions of the permanent magnets provided in place of the upper left and lower left permanent magnet units 20b are leftward, and the upper right and lower right permanent magnet units 20b. The magnetization directions of the permanent magnets provided instead of are respectively rightward. Moreover, the other magnetic field generator of the prior art here is provided with a permanent magnet having a magnetization direction inclined with respect to the surface in place of the permanent magnet unit 20b. In another conventional magnetic field generator, the magnetization direction of a permanent magnet provided in place of the permanent magnet unit 20b is the same as the substantial magnetization direction B of the permanent magnet unit 20b.

なお、いずれの磁界発生装置も空隙Ｓ２（図１０参照）に４．２５Ｔの磁界を発生させるように構成した。また、従来技術の他の磁界発生装置の傾いた磁化方向を有する永久磁石は、表面に対して垂直あるいは平行な磁化方向を有する永久磁石から切り出したものを用いた。   Each magnetic field generator was configured to generate a 4.25 T magnetic field in the air gap S2 (see FIG. 10). In addition, the permanent magnet having a tilted magnetization direction of another magnetic field generator of the prior art was cut from a permanent magnet having a magnetization direction perpendicular or parallel to the surface.

Figure 2007165741
Figure 2007165741

磁界発生装置２００と従来技術の磁界発生装置とを比較して、磁界発生装置２００では、永久磁石ユニット２０ｂを用いることによってより多くの磁束をポールピース２０４に集中させることができるので、従来技術の磁界発生装置に比べて永久磁石の総重量を小さくできることがわかる。ひいては、低コストに構成できることがわかる。   Compared with the magnetic field generator 200 and the prior art magnetic field generator, the magnetic field generator 200 can concentrate more magnetic flux on the pole piece 204 by using the permanent magnet unit 20b. It can be seen that the total weight of the permanent magnet can be reduced as compared with the magnetic field generator. As a result, it turns out that it can comprise at low cost.

また、磁界発生装置２００と従来技術の他の磁界発生装置とを比較して、従来技術の他の磁界発生装置では磁界発生装置２００よりも永久磁石のさらに総重量が小さくなっている。しかし、従来技術の他の磁界発生装置では、切り出すことによって得た永久磁石を用いるために、準備に必要な永久磁石の総重量が磁界発生装置２００よりも大きくなっている。このことから、磁界発生装置２００では、従来技術の他の磁界発生装置よりも低コストに構成できることがわかる。   Further, comparing the magnetic field generator 200 with another magnetic field generator of the prior art, the total weight of the permanent magnet is smaller than that of the magnetic field generator 200 in the other magnetic field generator of the prior art. However, in the other conventional magnetic field generators, the permanent magnets required for preparation are larger than the magnetic field generator 200 in order to use the permanent magnets obtained by cutting. From this, it can be seen that the magnetic field generator 200 can be configured at a lower cost than other magnetic field generators of the prior art.

このように磁界発生装置１００と同様に、磁界発生装置２００では、永久磁石ユニット２０ｂを用いることによって、永久磁石の量あるいはその準備に必要な永久磁石の量を削減でき、製造コストを低下させることができる。   Thus, in the same manner as the magnetic field generator 100, in the magnetic field generator 200, by using the permanent magnet unit 20b, the amount of permanent magnets or the amount of permanent magnets necessary for the preparation can be reduced, and the manufacturing cost can be reduced. Can do.

この発明の永久磁石ユニットの一例を示す分解斜視図解図である。It is a disassembled perspective view solution figure which shows an example of the permanent magnet unit of this invention. この発明の永久磁石ユニットの一例を示す図解図である。It is an illustration figure which shows an example of the permanent magnet unit of this invention. この発明の永久磁石ユニットの他の例を示す図解図である。It is an illustration figure which shows the other example of the permanent magnet unit of this invention. この発明の永久磁石ユニットのその他の例を示す図解図である。It is an illustration figure which shows the other example of the permanent magnet unit of this invention. この発明の永久磁石ユニットのその他の例を示し、（ａ）は一対の永久磁石を跨いで被覆部材が設けられる永久磁石ユニットの図解図であり、（ｂ）は一対の永久磁石の全ての表面に被覆部材が設けられる永久磁石ユニットの図解図である。The other example of the permanent magnet unit of this invention is shown, (a) is an illustration figure of the permanent magnet unit in which a coating | coated member is provided ranging over a pair of permanent magnet, (b) is the whole surface of a pair of permanent magnet It is an illustration figure of the permanent magnet unit by which a coating | coated member is provided. この発明の永久磁石ユニットを複数用いて構成される永久磁石ユニットを示し、（ａ）は図１および図２に示す永久磁石ユニットを２つ用いて構成される永久磁石ユニットの図解図であり、（ｂ）は図１および図２に示す永久磁石ユニットと図３に示す永久磁石ユニットとを１つずつ用いて構成される永久磁石ユニットの図解図である。The permanent magnet unit comprised using two or more permanent magnet units of this invention is shown, (a) is an illustration figure of a permanent magnet unit constituted using two permanent magnet units shown in Drawing 1 and Drawing 2, FIG. 4B is an illustrative view of a permanent magnet unit configured by using the permanent magnet unit shown in FIGS. 1 and 2 and the permanent magnet unit shown in FIG. 3 one by one. この発明の永久磁石ユニットのその他の例を示す斜視図解図である。It is a perspective view solution figure which shows the other example of the permanent magnet unit of this invention. この発明の永久磁石ユニットを備える磁界発生装置の一例を示す側面図解図である。It is a side view solution figure which shows an example of the magnetic field generator provided with the permanent magnet unit of this invention. 図８の磁界発生装置の環状突起および永久磁石ユニットを示す平面図解図である。It is a top view solution figure which shows the cyclic | annular protrusion and permanent magnet unit of the magnetic field generator of FIG. この発明の永久磁石ユニットを備える磁界発生装置の他の例を示す斜視図解図である。It is a perspective view solution figure which shows the other example of the magnetic field generator provided with the permanent magnet unit of this invention. 図１０の磁界発生装置の磁極ユニットを示し、（ａ）は上方に配置される磁極ユニットの平面図解図であり、（ｂ）は下方に配置される磁極ユニットの平面図解図である。The magnetic pole unit of the magnetic field generator of FIG. 10 is shown, (a) is a top plan solution view of the magnetic pole unit disposed above, and (b) is a plan view solution view of the magnetic pole unit disposed below. 従来の永久磁石を示す図解図である。It is an illustration figure which shows the conventional permanent magnet.

符号の説明Explanation of symbols

１０，１０ａ，１０ｂ，１０ｃ，１０ｄ，１０ｅ，１０ｆ，２０，２０ａ，２０ｂ，３０ 永久磁石ユニット
１２，１２ａ，１２ｂ，１３，２０６，２０８ 永久磁石
１８ 介挿部材
１９，１９ａ 被覆部材
１００，２００ 磁界発生装置
１０８ａ，１０８ｂ 磁極片
１１６ 環状突起
Ａ，Ａ１，Ｂ，Ｃ 磁化方向 10, 10a, 10b, 10c, 10d, 10e, 10f, 20, 20a, 20b, 30 Permanent magnet unit 12, 12a, 12b, 13, 206, 208 Permanent magnet 18 Insertion member 19, 19a Cover member 100, 200 Magnetic field Generator 108a, 108b Pole piece 116 Annular projection A, A1, B, C Magnetization direction

Claims (7)

それぞれ直方体状に形成されかつ表面に対して垂直あるいは平行な磁化方向を有する一対の永久磁石を備え、
前記一対の永久磁石は互いの前記磁化方向を９０°異ならせて磁気的に結合される、永久磁石ユニット。 A pair of permanent magnets each formed in a rectangular parallelepiped shape and having a magnetization direction perpendicular or parallel to the surface;
The pair of permanent magnets is a permanent magnet unit that is magnetically coupled so that the magnetization directions thereof are different from each other by 90 °. 前記永久磁石が接触する、請求項１に記載の永久磁石ユニット。   The permanent magnet unit according to claim 1, wherein the permanent magnet contacts. 非磁性体からなり前記永久磁石間に介挿される介挿部材をさらに含む、請求項１に記載の永久磁石ユニット。   The permanent magnet unit according to claim 1, further comprising an insertion member made of a nonmagnetic material and interposed between the permanent magnets. 非磁性体からなり前記一対の永久磁石を跨いで前記一対の永久磁石に設けられる被覆部材をさらに含む、請求項１から３のいずれかに記載の永久磁石ユニット。   The permanent magnet unit according to claim 1, further comprising a covering member made of a nonmagnetic material and provided on the pair of permanent magnets across the pair of permanent magnets. 請求項１から４のいずれかに記載の永久磁石ユニットを備える、磁界発生装置。   A magnetic field generator comprising the permanent magnet unit according to claim 1. 外側面に前記永久磁石ユニットが設けられる環状突起をそれぞれ有し空隙を介して対向配置される一対の磁極片をさらに含み、
前記永久磁石ユニットの前記一対の永久磁石は前記環状突起の径方向に並置され、内側の前記永久磁石の前記磁化方向は前記径方向に向けられかつ外側の前記永久磁石の前記磁化方向は前記環状突起の軸方向に向けられる、請求項５に記載の磁界発生装置。 Further comprising a pair of magnetic pole pieces each having an annular protrusion on which the permanent magnet unit is provided on the outer surface and arranged to face each other via a gap,
The pair of permanent magnets of the permanent magnet unit are juxtaposed in the radial direction of the annular protrusion, the magnetization direction of the inner permanent magnet is directed to the radial direction, and the magnetization direction of the outer permanent magnet is the annular shape. The magnetic field generator according to claim 5, wherein the magnetic field generator is directed in an axial direction of the protrusion. 前記内側の永久磁石は前記外側の永久磁石よりも保磁力が大きい、請求項６に記載の磁界発生装置。
The magnetic field generator according to claim 6, wherein the inner permanent magnet has a coercive force larger than that of the outer permanent magnet.
JP2005362657A 2005-12-16 2005-12-16 Permanent magnet unit and magnetic field generator provided therewith Pending JP2007165741A (en)

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