JP2008282909A - Method for manufacturing ring-shaped magnet - Google Patents
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Abstract
Description
本発明は、リング状磁石の製造方法に関する。 The present invention relates to a method for manufacturing a ring-shaped magnet.
従来、磁性粉をラジアル方向(リング状磁石の半径方向)に磁場配向させてラジアル異方性リング状磁石を製造する代表的な方法としては、(1)磁性粉がリング状に収容される円筒状キャビティを軸方向に貫通する軟磁性コアに垂直方向磁場を印加し、軟磁性コアの外周に配置した軟磁性ダイを通る磁束を発生させて、キャビティ内の磁性粉をラジアル方向に配向させた状態でプレス成形する方法(例えば、特許文献1及び2参照)や、(2)磁性粉がリング状に収容された円筒状キャビティに直線的な水平横磁場のみを印加し、その磁場方向を90°回転させながらプレス成形することにより、概ねラジアル方向に配向されたリング状磁石を得る方法(例えば、特許文献3及び4参照)が提案されている。
しかし、上記従来(1)の方法では、リング状磁石の(円)周方向に亘って均等なラジアル磁場を発生させ易いものの、例えば特許文献2における従来技術の説明においても言及されているとおり、強い磁場によるラジアル配向が可能な軸方向長さ(高さ)の範囲は、軟磁性コアの飽和磁化に起因して狭い範囲に制限されてしまうため、ある程度長尺なリング状(筒状)磁石を得るには、磁場印加とプレス成形を繰り返すことにより、短尺のリング状成形体を多段に重ねて円筒状磁石とする必要がある。こうなると、工程数及び工程時間が増大してしまい、生産効率の低下及び製造コストの増大を招いてしまう。また、軸方向(高さ方向)に隣接する短尺のリング状成形体の境界部において、不可避的に磁場の不連続部分が生じてしまうので、軸方向(高さ方向)における磁気特性の均一性が損なわれてしまう傾向にある。 However, in the conventional method (1), it is easy to generate a uniform radial magnetic field over the (circular) circumferential direction of the ring-shaped magnet, but as mentioned in the description of the prior art in Patent Document 2, for example, The range of axial length (height) in which radial alignment by a strong magnetic field is possible is limited to a narrow range due to the saturation magnetization of the soft magnetic core, so a somewhat long ring-shaped (cylindrical) magnet In order to obtain the above, it is necessary to repeat the application of the magnetic field and press molding, thereby stacking the short ring-shaped molded body in multiple stages to form a cylindrical magnet. If it becomes like this, the number of processes and process time will increase, and the fall of production efficiency and the increase of manufacturing cost will be caused. In addition, a magnetic field discontinuity is inevitably generated at the boundary of the short ring-shaped molded product adjacent to the axial direction (height direction), so the magnetic characteristics are uniform in the axial direction (height direction). Tend to be damaged.
また、多段階的にプレス成形を行なう必要があるので、各プレス工程において磁性粉の密度を調整したとしても、例えば、最初にプレス成形された部位と最後にプレス成形された部位において、成形体の密度ひいては表面残留磁束密度(Br)の有意な差異が生じ得るおそれがあり、この場合にも、軸方向(高さ方向)の磁気特性の均一性が悪化してしまう可能性がある。また、プレス成形によって圧力が印加される回数が比較的多くなる部位(最初の方でプレス成形された部位)においては、一旦配向した磁性粉が動いてしまう可能性が比較的高まるので、得られるリング状磁石のラジアル方向における配向度及びBrの均一性も損なわれてしまう懸念がある。 In addition, since it is necessary to perform press molding in multiple steps, even if the density of the magnetic powder is adjusted in each press process, for example, in the first press-formed part and the last press-formed part, As a result, a significant difference in surface residual magnetic flux density (Br) may occur, and in this case, the uniformity of the magnetic characteristics in the axial direction (height direction) may be deteriorated. In addition, in a portion where the number of times pressure is applied by press molding is relatively large (a portion that is press-molded in the first direction), the possibility that the magnetic powder once oriented moves relatively increases, so that it can be obtained. There is a concern that the degree of orientation in the radial direction of the ring-shaped magnet and the uniformity of Br may be impaired.
一方、上記従来(2)の方法では、円筒軸方向に比較的長尺なリング状磁石を得ることが可能となるが、配向度及びBrが、円周方向において90°周期で顕著に増減してしまう傾向にある。こうなると、リング状磁石を表面永久磁石型同期モータ(SPMSM)等に用いた場合、トルクリプルやコギングトルク等が発生し易くなり、それに起因して周期的なトルク変動が増大してしまうおそれがある。 On the other hand, in the conventional method (2), it is possible to obtain a relatively long ring magnet in the cylindrical axis direction, but the degree of orientation and Br significantly increase and decrease at 90 ° intervals in the circumferential direction. It tends to end up. In this case, when the ring-shaped magnet is used for a surface permanent magnet type synchronous motor (SPMSM) or the like, torque ripple, cogging torque or the like is likely to be generated, and there is a risk that periodic torque fluctuations increase due to this. .
そこで、本発明は、かかる事情に鑑みてなされたものであり、周方向及び軸方向(高さ方向)における配向度及び表面残留磁束密度(Br)の均一性に優れた比較的長尺なリング状磁石を得ることができ、しかも、生産効率及び経済性を格段に向上させることができるリング状磁石の製造方法及びそのリング状磁石を提供することを目的とする。 Therefore, the present invention has been made in view of such circumstances, and is a relatively long ring excellent in the degree of orientation in the circumferential direction and the axial direction (height direction) and the uniformity of the surface residual magnetic flux density (Br). It is an object of the present invention to provide a ring-shaped magnet manufacturing method and a ring-shaped magnet that can obtain a ring-shaped magnet and can significantly improve production efficiency and economy.
上記課題を解決するために、本発明によるリング状磁石の製造方法は、筒状をなすキャビティ内を軸方向に貫通する軟磁性材料からなるコア部と、そのキャビティの外周に沿って(周方向に)所定角度間隔で配置された3個以上の磁極部とを備える電磁石を準備する準備工程と、キャビティ内に磁性粉を収容する収容工程と、3個以上の磁極部のうち互いに隣接する少なくとも2個の磁極部を同一の極性(N極又はS極)として一方極を構成し、且つ、3個以上の磁極部のうち一方極と対向する少なくとも1個の磁極部を反対の極性として他方極を構成し、キャビティに収容された磁性粉に、その一方極と他方極で形成される磁場を印加する磁化工程と、キャビティに収容された磁性粉を加圧成形する成形工程とを有しており、磁化工程においては、キャビティに収容された磁性粉の周方向全体に亘ってラジアル方向又は略ラジアル方向の磁場が印加されるように、一方極及び他方極の各々を構成する磁極部の組み合わせを経時的に変化させながら(選択する磁極部の組み合わせを順次変えながら)、磁性粉に磁場を印加する方法である。なお、本発明において「リング状」とは、短尺な環状体のみならず、一定の軸方向長さ(高さ)を有する筒状の環状体を含み、真円状又は略真円状であることが望ましい。 In order to solve the above-described problems, a method of manufacturing a ring-shaped magnet according to the present invention includes a core portion made of a soft magnetic material that penetrates a cylindrical cavity in an axial direction, and an outer periphery of the cavity (circumferential direction). (Ii) a preparation step of preparing an electromagnet including three or more magnetic pole portions arranged at a predetermined angular interval, an accommodating step of containing magnetic powder in the cavity, and at least adjacent to each other among the three or more magnetic pole portions. One pole is configured with two magnetic pole portions having the same polarity (N pole or S pole), and at least one of the three or more magnetic pole portions opposite to one pole is set with the opposite polarity to the other A magnetic step of forming a pole and applying a magnetic field formed by one of the poles to the magnetic powder accommodated in the cavity, and a molding step of pressure-molding the magnetic powder accommodated in the cavity In the magnetization process Thus, the combination of the magnetic pole portions constituting each of the one pole and the other pole is changed with time so that a magnetic field in the radial direction or substantially radial direction is applied over the entire circumferential direction of the magnetic powder accommodated in the cavity. This is a method in which a magnetic field is applied to magnetic powder while changing (sequentially changing the combination of magnetic pole portions to be selected). In the present invention, the “ring shape” includes not only a short annular body but also a cylindrical annular body having a certain axial length (height), and is a perfect circle or a substantially perfect circle. It is desirable.
このような製造方法では、まず、準備工程において、リング状磁石の原料である磁性粉を磁化するための装置部材、すなわち、上記の如く磁性粉が収容される筒状のキャビティの内部を軸方向に貫通するコア部、及び、キャビティの外周に沿って所定角度間隔で配置された3個以上の磁極部を備える電磁石が用意される。磁極部は、単独で又は複合的に、磁性粉に磁場を印加するための磁極として機能するものであり、本発明に用いる3個以上の各磁極部は、それぞれ独立して極性が制御され得るものである。次に、電磁石によって磁場が印加される位置に設置されたキャビティ内に磁性粉を必要量収容する。それから、この状態で磁化工程を実施し、3個以上の磁極部のうち互いに隣接する少なくとも2個の磁極部が同一の極性を有するように、且つ、それらの磁極部に対向する少なくとも1個の磁極部が反対の極性を有するように、電磁石に電力を供給する。 In such a manufacturing method, first, in the preparation step, the device member for magnetizing the magnetic powder that is the raw material of the ring magnet, that is, the inside of the cylindrical cavity in which the magnetic powder is accommodated as described above is axially disposed. And an electromagnet including three or more magnetic pole portions arranged at predetermined angular intervals along the outer periphery of the cavity. The magnetic pole part functions alone or in combination as a magnetic pole for applying a magnetic field to the magnetic powder, and the polarity of each of the three or more magnetic pole parts used in the present invention can be controlled independently. Is. Next, a required amount of magnetic powder is accommodated in a cavity installed at a position where a magnetic field is applied by an electromagnet. Then, the magnetization process is performed in this state, and at least one of the three or more magnetic pole portions adjacent to each other has the same polarity and at least one of the magnetic pole portions facing each other. Electric power is supplied to the electromagnet so that the magnetic pole portions have opposite polarities.
これにより、選択された少なくとも2個以上の磁極部は、全体として1つの一方極として機能し、それらに対向する磁極部、例えば、磁極部が偶数個配置されていれば、キャビティの周方向において対称位置(180°対向する位置)に配置された少なくとも2個以上の磁極部、或いは、磁極部が奇数個配置されていれば、キャビティの周方向において対称位置に近い少なくとも2個以上の磁極部が、全体として1つの他方極(反対極)として機能し、その結果、キャビティに収容された磁性粉に、一方極と他方極で形成された磁場が印加される。この磁場は、前記従来(2)の方法の如く180°方向に配置された異なる磁極部間を単に横断するような直線方向の磁場ではなく、磁力線が、キャビティの壁面に対して直交するようにつまりラジアル方向に入射し、コア部を略直線的に通過して、反対側のキャビティの壁面に対して直交するようにつまりラジアル方向に出射するような曲線的な磁束を有する。 Thereby, at least two or more selected magnetic pole portions function as one unipolar pole as a whole, and if an even number of magnetic pole portions, for example, magnetic pole portions, are arranged, they are arranged in the circumferential direction of the cavity. At least two or more magnetic pole portions arranged at symmetrical positions (positions facing 180 °), or at least two or more magnetic pole portions close to symmetrical positions in the circumferential direction of the cavity if odd number of magnetic pole portions are arranged. However, it functions as one other pole (opposite pole) as a whole, and as a result, a magnetic field formed by one pole and the other pole is applied to the magnetic powder accommodated in the cavity. This magnetic field is not a linear magnetic field that simply traverses between the different magnetic pole portions arranged in the 180 ° direction as in the method of the prior art (2), but the magnetic field lines are orthogonal to the wall surface of the cavity. That is, it has a curvilinear magnetic flux that is incident in the radial direction, passes through the core portion substantially linearly, and exits in the radial direction so as to be orthogonal to the wall surface of the opposite cavity.
このように、互いに隣接する少なくとも2個の磁極部が同一の極性であれば、キャビティ内の磁性粉の周方向の少なくとも一部がラジアル配向される。この際、キャビティの外周において、上記一方極と他方極(反対極)との間に相当する位置に印加磁場が小さい領域が生じ得るが、この場合、経時的に、一方極及び他方極の各々を構成する同一極性の磁極部の組み合わせを、その印加磁場が小さい領域にラジアル方向の磁場が印加されるような組み合わせに随時変化させながら(換言すれば、磁性粉に対して磁場を経時的に回転させながら)、磁場印加を言わば段階的且つ連続的又は断続的に実施することにより、磁性粉の周方向全体に亘って均等なラジアル方向又は略ラジアル方向の磁場を印加することができる。 Thus, if at least two magnetic pole portions adjacent to each other have the same polarity, at least a part of the circumferential direction of the magnetic powder in the cavity is radially oriented. At this time, in the outer periphery of the cavity, a region where the applied magnetic field is small may occur at a position corresponding to the position between the one pole and the other pole (opposite pole). While changing the combination of magnetic pole portions of the same polarity constituting the magnetic field to a combination in which a radial magnetic field is applied to a region where the applied magnetic field is small (in other words, the magnetic field is changed over time with respect to the magnetic powder). By rotating the magnetic field in a stepwise and continuous or intermittent manner, the magnetic field can be applied in a uniform radial direction or substantially radial direction over the entire circumferential direction of the magnetic powder.
そして、本発明によるリング状磁石の製造方法は、上記従来(1)の方法の如くコアに垂直方向の磁場を印加することによってラジアル方向の磁場を生じせしめる方法ではないので、ラジアル配向が可能な軸方向長さ(高さ)に制限がない。よって、磁極部の高さを、目的とするリング状磁石の軸方向長さに応じた値とすることにより、短尺のリング状成形体の磁化及び成形を複数回繰り返してそれらを積層することなく、所望長の長尺なリング状磁石が簡易に得られる。すなわち、キャビティ内の磁性粉が均等なラジアル磁化状態となった後、一度の成形工程によってその磁性粉を加圧成形し、その他適宜必要な工程を施すことにより、ラジアル異方性を有する所望長のリング状磁石が得られる。 The method of manufacturing a ring magnet according to the present invention is not a method of generating a radial magnetic field by applying a vertical magnetic field to the core as in the conventional method (1). There is no limit on the axial length (height). Therefore, by setting the height of the magnetic pole part to a value corresponding to the axial length of the target ring-shaped magnet, the magnetization and shaping of the short ring-shaped molded body are repeated a plurality of times without laminating them. A long ring magnet having a desired length can be easily obtained. That is, after the magnetic powder in the cavity is in a uniform radial magnetization state, the magnetic powder is pressure-molded by a single molding process, and other necessary processes are performed to obtain a desired length having radial anisotropy. A ring-shaped magnet is obtained.
また、電磁石として、磁極部を偶数個備えるものを用いることが好ましい。ここで、磁極部を奇数個備える場合、一方極として機能する磁極部と他方極として機能する磁極部の数が異なるため、一方極を構成する磁極部と他方極を構成する磁極部とに印加される磁場強度に差異が生じてしまい、或いは、磁場の対称性が損なわれ磁場のバイパス効果によって磁場強度が低下し易くなることがある。そのため、ラジアル方向の磁化の均一性を高めるには、同一極性の磁極部の組み合わせを、キャビティの全周に亘って印加される磁場強度が平均化されるように経時的に変化させるといった制御を行なうことが望ましい。これに対し、磁極部を偶数個備える電磁石を用いることにより、そのような磁極部が奇数個の場合の制御が不要となり、また、後記のとおり、磁極部を6個以上備える場合には、少なくとも1対の対向配置された磁極部に磁場を印加しないことにより、一方極が寄与する磁場と他方極が寄与する磁場を打ち消すといった制御が可能となる、より強力なラジアル方向磁場を生起させ易くなる。 Moreover, it is preferable to use an electromagnet having an even number of magnetic pole portions. Here, when an odd number of magnetic pole parts are provided, the number of magnetic pole parts that function as one pole and the number of magnetic pole parts that function as the other pole are different, so that the magnetic pole part that constitutes one pole and the magnetic pole part that constitutes the other pole are applied. In some cases, a difference occurs in the strength of the magnetic field, or the symmetry of the magnetic field is lost and the magnetic field strength is likely to decrease due to the bypass effect of the magnetic field. For this reason, in order to increase the uniformity of the magnetization in the radial direction, control is performed such that the combination of magnetic pole portions having the same polarity is changed over time so that the magnetic field strength applied over the entire circumference of the cavity is averaged. It is desirable to do so. On the other hand, by using an electromagnet having an even number of magnetic pole parts, control in the case of an odd number of such magnetic pole parts becomes unnecessary, and, as will be described later, in the case of having six or more magnetic pole parts, By not applying a magnetic field to a pair of opposed magnetic poles, it is possible to control to cancel the magnetic field contributed by one pole and the magnetic field contributed by the other pole, and it is easy to generate a stronger radial direction magnetic field. .
より具体的には、電磁石としてキャビティの外周に沿って90°又は略90°間隔で配置された4個の磁極部を備えるものを用いると有用である。この場合、磁化工程において一方極及び他方極の各々を構成する磁極部の組み合わせを経時的に変化させる手順としては、4個の磁極部のうち隣接する2個の磁極部を同一の極性として一方極を構成し、その一方極の2個の磁極部と(180°)対向する2個の磁極部を反対の極性として他方極を構成した状態で磁性粉に磁場を印加した後、一方極及び他方極の各々の2個の磁極部の組み合わせを、周方向に磁極部1個分変化(変位、シフト)させた状態、すなわち、一方極と他方極とで形成される磁場を90°回転させた状態で磁性粉に磁場を印加すると好ましい。 More specifically, it is useful to use an electromagnet having four magnetic pole portions arranged at intervals of 90 ° or approximately 90 ° along the outer periphery of the cavity. In this case, as a procedure for changing the combination of the magnetic pole portions constituting each of the one pole and the other pole with time in the magnetization process, two adjacent magnetic pole portions of the four magnetic pole portions are set to have the same polarity. After forming a pole and applying a magnetic field to the magnetic powder in a state where the other pole is configured with the two pole parts facing each other (180 °) opposite to the two pole parts of the one pole, the one pole and The combination of the two magnetic pole portions of each of the other poles is changed (displaced, shifted) in the circumferential direction by one magnetic pole portion, that is, the magnetic field formed by one pole and the other pole is rotated by 90 °. It is preferable to apply a magnetic field to the magnetic powder in such a state.
こうすれば、最初の磁場印加において、一方極の2個の磁極部から他方極の2個の磁極部へ向かって、キャビティの周壁に対して磁力線が垂直に入出射するようなラジアル方向の磁場が形成され、磁性粉の周方向において、一方極を構成する2個の磁極部間に相当する部位がラジアル方向に磁化(配向)される。その際、一方極の磁極部と他方極の磁極部間に相当する領域では、ラジアル方向の磁化が不十分となるが、その後、磁場方向が90°回転するように、具体的には、初回の磁場印加における一方極の磁極部の1個と他方極の磁極部の1個が同一極性となるように、磁場を印加することにより、初回の磁場印加においてラジアル配向が不十分であった磁性粉の部位にラジアル方向の磁場が印加され、磁性粉の周方向全体に亘って均等なラジアル配向が達成される。 In this way, in the initial application of the magnetic field, the magnetic field in the radial direction is such that the magnetic lines of force enter and exit perpendicularly with respect to the peripheral wall of the cavity from the two magnetic pole portions of one pole toward the two magnetic pole portions of the other pole. In the circumferential direction of the magnetic powder, a portion corresponding to the two magnetic pole portions constituting the one pole is magnetized (oriented) in the radial direction. At that time, in the region corresponding to the magnetic pole part of one pole and the magnetic pole part of the other pole, the magnetization in the radial direction becomes insufficient. When the magnetic field is applied so that one of the magnetic pole portions of one pole and one of the magnetic pole portions of the other pole have the same polarity, the magnetic orientation in which the radial orientation is insufficient in the first magnetic field application A magnetic field in the radial direction is applied to the powder portion, and uniform radial orientation is achieved over the entire circumferential direction of the magnetic powder.
或いは、電磁石として、キャビティの外周に沿って60°又は略60°間隔で配置された6個の前記磁極部を有するものを用いるとより好適である。この場合、磁化工程において一方極及び他方極の各々を構成する磁極部の組み合わせを経時的に変化させる手順としては、6個の磁極部のうち隣接する2個の磁極部を同一の極性として一方極を構成し、隣その一方極の2個の磁極部と(180°)対向する2個の磁極部を反対の極性として他方極を構成した状態で磁性粉に磁場を印加した後、その一方極及び他方極の各々の磁極部の組み合わせを、周方向に磁極部1個分又は2個分変化させた状態、すなわち、一方極と他方極とで形成される磁場を60°又は120°回転させた状態で磁性粉に磁場を印加することが好ましい。なお、磁場を60°回転させた状態での磁場印加と120°変化させた状態での磁場印加の両方を経時的に実施しても構わず、この場合、順序を問わずいずれを先に実施してもよい。 Alternatively, it is more preferable to use an electromagnet having six magnetic pole portions arranged at intervals of 60 ° or approximately 60 ° along the outer periphery of the cavity. In this case, as a procedure for changing the combination of the magnetic pole portions constituting each of the one pole and the other pole with time in the magnetization step, two adjacent magnetic pole portions of the six magnetic pole portions are set to have the same polarity. After applying a magnetic field to the magnetic powder in a state in which the other pole is formed with two poles that are opposite to each other (180 °) and two poles that are opposite to each other (180 °). The combination of the magnetic pole portions of the pole and the other pole is changed in the circumferential direction by one or two magnetic pole portions, that is, the magnetic field formed by one pole and the other pole is rotated by 60 ° or 120 ° It is preferable to apply a magnetic field to the magnetic powder in such a state. Note that both the magnetic field application with the magnetic field rotated by 60 ° and the magnetic field application with the state changed by 120 ° may be performed over time. In this case, whichever is performed first, regardless of the order. May be.
このようにすれば、最初の磁場印加において、60°間隔で配置された2個の磁極部で構成される一方極から、対称配置された2個の磁極部で構成される他方極へ向かい、キャビティの周壁に対して磁力線が垂直に入出射するようなラジアル方向の磁場が形成され、磁性粉の周方向において、一方極を構成する2個の磁極部間に相当する部位と、他方極を構成する2個の磁極部間に相当する部位の両方の広い範囲がラジアル方向に磁化される。 In this way, in the first magnetic field application, from one pole composed of two magnetic pole portions arranged at intervals of 60 ° to the other pole composed of two magnetic pole portions arranged symmetrically, A radial magnetic field is formed so that the magnetic field lines enter and exit perpendicularly to the peripheral wall of the cavity, and in the circumferential direction of the magnetic powder, a portion corresponding to the two magnetic pole portions constituting one pole and the other pole are formed. A wide range of both portions corresponding to the two magnetic pole portions constituting the magnet is magnetized in the radial direction.
このとき、6個の磁極部のうち4個の磁極部が磁場を形成する磁極として機能する一方で、一方極と他方極との間に180°対向配置された一対の磁極部は磁極として機能せず、この一対の磁極部には実質的に磁場が印加されない。その結果、その一対の磁極部において、一方極によって形成される磁場と他方極によって形成される磁場が打ち消し合うことにより、磁性粉の周方向において、その一対の磁極部の先端部に相当する部位以外に強力なラジアル方向の磁場が形成される。すなわち、磁性粉の周方向において、一方極を構成する2個の磁極部間に相当する部位と、他方極を構成する2個の磁極部間に相当する部位のラジアル方向磁場の強度が顕著に高められる。 At this time, four of the six magnetic pole portions function as magnetic poles for forming a magnetic field, while a pair of magnetic pole portions disposed to face each other at 180 ° between the one pole and the other pole function as magnetic poles. Thus, a magnetic field is not substantially applied to the pair of magnetic pole portions. As a result, in the pair of magnetic pole portions, the magnetic field formed by the one pole and the magnetic field formed by the other pole cancel each other, so that the portion corresponding to the tip of the pair of magnetic pole portions in the circumferential direction of the magnetic powder Besides, a strong radial magnetic field is formed. That is, in the circumferential direction of the magnetic powder, the intensity of the radial magnetic field at the portion corresponding to between the two magnetic pole portions constituting the one pole and the portion corresponding to between the two magnetic pole portions constituting the other pole is remarkable. Enhanced.
このように、電磁石として、少なくとも6個以上の磁極部を有するものを用い、且つ、磁化工程においては、一方極と他方極との間に対向配置された少なくとも1対の磁極部に電力を供給せず(具体的には、例えばその一対の磁極部のコイルに通電せず)、これにより実質的に磁場を印加しないことが好ましい。 As described above, an electromagnet having at least six magnetic pole portions is used, and in the magnetization process, power is supplied to at least one pair of magnetic pole portions arranged to face each other between the one pole and the other pole. (Specifically, for example, it is preferable not to energize the coils of the pair of magnetic pole portions), and thereby it is preferable that substantially no magnetic field is applied.
またさらに、電磁石として、キャビティの外周に沿って45°又は略45°間隔で配置された8個の磁極部を備えるものを用いても有用である。この場合、磁化工程において一方極及び他方極の各々を構成する磁極部の組み合わせを経時的に変化させる手順としては、8個の磁極部のうち隣接する2個又は3個の磁極部を同一の極性として一方極を構成し、その一方極を構成する2個又は3個の磁極部と(180°)対向する2個又は3個の磁極部を反対の極性として他方極を構成した状態で磁性粉に磁場を印加した後、一方極及び他方極の各々の2個又は3個の磁極部の組み合わせを、周方向に磁極部1個分、2個分、又は3個分変化させた状態、すなわち、一方極と他方極とで形成される磁場を45°、90°、又は135°回転させた状態で磁性粉に磁場を印加することが好ましい。なお、磁場を45°回転させた状態での磁場印加、90°回転させた状態での磁場印加、及び135°変化させた状態での磁場印加の一部又は全部を経時的に実施しても構わず、この場合、順序を問わずいずれを先に実施してもよい。 Further, it is useful to use an electromagnet having eight magnetic pole portions arranged at 45 ° or substantially 45 ° intervals along the outer periphery of the cavity. In this case, as a procedure of changing the combination of the magnetic pole portions constituting each of the one pole and the other pole with time in the magnetization process, adjacent two or three magnetic pole portions among the eight magnetic pole portions are the same. Magnetic in a state where one pole is configured as the polarity, and the other pole is configured with two or three magnetic pole portions that are opposite to the two or three magnetic pole portions constituting the one pole (180 °) opposite to each other. After applying a magnetic field to the powder, a state in which the combination of two or three magnetic pole portions of each of the one pole and the other pole is changed in the circumferential direction by one magnetic pole portion, two pieces, or three pieces, That is, it is preferable to apply the magnetic field to the magnetic powder in a state where the magnetic field formed by the one pole and the other pole is rotated by 45 °, 90 °, or 135 °. Note that a part or all of the magnetic field application in a state where the magnetic field is rotated by 45 °, the magnetic field application in a state where the magnetic field is rotated by 90 °, and the magnetic field application in a state where the magnetic field is changed by 135 ° may be performed over time. Regardless, in this case, either may be performed first regardless of the order.
このようにしても、最初の磁場印加において、45°間隔で配置された2個又は3個の磁極部で構成される一方極から、対称配置された2個又は3個の磁極部で構成される他方極へ向かい、キャビティの周壁に対して磁力線が垂直に入出射するようなラジアル方向の磁場が形成され、磁性粉の周方向において、一方極に相当する部位と、他方極に相当する部位の広い範囲がラジアル方向に磁化され、上述のように磁場を回転させて順次磁場印加を実施することにより、磁性粉の周方向全体がラジアル方向に磁化される。なお、この磁化工程においては、最終的に8個の磁極部の全てがいずれかの磁場配向に関与するように、一方極及び他方極の各々の磁極部の組み合わせを経時的に変化させることが望ましい。 Even in this case, in the initial application of the magnetic field, it is composed of two or three magnetic pole portions arranged symmetrically from one pole composed of two or three magnetic pole portions arranged at 45 ° intervals. A radial magnetic field is formed so that the magnetic field lines enter and exit perpendicularly to the peripheral wall of the cavity, and in the circumferential direction of the magnetic powder, a portion corresponding to one pole and a portion corresponding to the other pole The entire magnetic powder is magnetized in the radial direction by rotating the magnetic field as described above and sequentially applying the magnetic field. In this magnetization step, the combination of the magnetic pole portions of the one pole and the other pole can be changed over time so that all of the eight magnetic pole portions are ultimately involved in any magnetic field orientation. desirable.
さらに、電磁石として、キャビティの外周において、一方極及び/又は他方極の両縁端、換言すれば、一方極及び/又は他方極を構成する少なくとも2個の磁極部の最外に位置する磁極部の両縁端(最外端同士)のなす角度が略120°のものを用いると好適である。このようにすれば、同一極性の磁極部の範囲に相当する(つまり、同一極性の磁極でカバーされる)磁性粉の周弧の長さが、キャビティの直径に略等しくなる。逆に、同一の極性とされた少なくとも2個の磁極部の両縁端のなす角度が略120°を超えると、同一極性の磁極部の範囲に相当する磁性粉の周弧の長さが、キャビティの直径を上回り、こうなると、コア内の磁束密度が飽和し易くなり、言わば磁束の一部がコアの外部へ漏出するように、磁束の方向が直線方向に偏向してしまう。その結果、ラジアル配向の程度が減弱されてしまう。よって、同一の極性とされた少なくとも2個の磁極部の両縁端のなす角度が略120°のものを用いれば、磁性粉の周方向における広い範囲でラジアル方向の配向度及びその均一性が高められる。 Furthermore, as an electromagnet, at the outer periphery of the cavity, the magnetic pole part located at the outermost edge of at least two magnetic pole parts constituting the one pole and / or the other pole, in other words, both edges of the one pole and / or the other pole It is preferable to use one having an angle formed by both edges (outermost ends) of approximately 120 °. By doing so, the length of the circumferential arc of the magnetic powder corresponding to the range of the magnetic pole portions of the same polarity (that is, covered by the magnetic poles of the same polarity) becomes substantially equal to the diameter of the cavity. Conversely, when the angle formed by both edges of at least two magnetic pole parts having the same polarity exceeds approximately 120 °, the length of the circumferential arc of the magnetic powder corresponding to the range of the magnetic pole parts of the same polarity is If it exceeds the diameter of the cavity and this happens, the magnetic flux density in the core tends to be saturated, so that the direction of the magnetic flux is deflected in a linear direction so that part of the magnetic flux leaks out of the core. As a result, the degree of radial orientation is reduced. Therefore, if the angle formed by the edges of at least two magnetic pole portions having the same polarity is approximately 120 °, the degree of orientation in the radial direction and the uniformity thereof are wide in the circumferential direction of the magnetic powder. Enhanced.
また、本発明によるリング状磁石は、本発明のリング状磁石の製造方法を用いて有効に製造されるものであり、軸方向長さ(高さ)Lが内径riの1/2よりも大きく且つ一体成形されたリング状をなし、磁性粉の原料の形態や性状、キャビティへの充填状態等に依存するものの、周方向の配向度の変動率が、例えば、好ましくは5%未満、より好ましくは3%未満であり、且つ、軸方向(高さ方向)の配向度の変動率が、例えば、好ましくは2%未満、より好ましくは1%未満のものである。なお、本発明における「周方向の配向度の変動率」とは、リング状磁石の軸方向長さ中心において、X線回折装置を用いてリング状磁石の周方向の全周(360°)に亘って所定角度間隔(10°〜20°程度)で配向度を測定し、得られた数値データの標準偏差(1σ)を平均値で除した値の百分率を示す。また、本発明における「周方向の配向度の変動率」とは、リング状磁石の周方向の任意位置において、X線回折装置を用いてリング状磁石の軸方向の全長に亘って所定寸法間隔(軸方向長さの5%程度)で配向度を測定し、得られた数値データの標準偏差(1σ)を平均値で除した百分率を示す。 In addition, the ring-shaped magnet according to the present invention is effectively manufactured by using the method for manufacturing a ring-shaped magnet according to the present invention, and the axial length (height) L is less than ½ of the inner diameter r i. Although the ring shape is large and integrally formed, and depends on the form and properties of the raw material of the magnetic powder, the state of filling in the cavity, etc., the variation rate of the degree of orientation in the circumferential direction is preferably less than 5%, for example. Preferably, it is less than 3%, and the variation rate of the degree of orientation in the axial direction (height direction) is, for example, preferably less than 2%, more preferably less than 1%. In the present invention, the “rate of variation in the degree of orientation in the circumferential direction” means the entire circumference (360 °) in the circumferential direction of the ring magnet using an X-ray diffractometer at the center of the axial length of the ring magnet. The degree of orientation is measured at predetermined angular intervals (about 10 ° to 20 °), and the percentage of the value obtained by dividing the standard deviation (1σ) of the obtained numerical data by the average value is shown. Further, the “rate of variation in the degree of orientation in the circumferential direction” in the present invention means a predetermined dimensional interval over the entire axial length of the ring magnet using an X-ray diffractometer at an arbitrary position in the circumferential direction of the ring magnet. The degree of orientation is measured at (approximately 5% of the axial length), and the percentage obtained by dividing the standard deviation (1σ) of the obtained numerical data by the average value is shown.
本発明のリング状磁石の製造方法によれば、磁化工程において、3個以上の磁極部のうち互いに隣接する少なくとも2個の磁極部を同一の極性として一方極を構成し、且つ、その一方極と対向する少なくとも1個の磁極部を反対の極性として他方極を構成し、それら一方極及び他方極の各々を構成する磁極部の組み合わせを経時的に変化させながら、キャビティに収容された磁性粉に磁場を印加するので、磁性粉の周方向全体をラジアル方向又は略ラジアル方向に配向させることできる。よって、円周方向における配向度及びBrの均一性に優れたリング状磁石を得ることができる。また、コアに垂直ではなく水平な磁場を用いた磁場配向を行なうので、長尺なリング状磁石を得るのに、複数の成形体を積層する必要がない。よって、軸方向(高さ方向)における配向度及びBrの均一性にも優れたリング状磁石を得ることができる。 According to the method of manufacturing a ring-shaped magnet of the present invention, in the magnetization step, one pole is formed with at least two magnetic pole portions adjacent to each other among the three or more magnetic pole portions having the same polarity, and the one pole The magnetic powder accommodated in the cavity is configured with the other pole having the opposite polarity as the opposite pole and the combination of the magnetic pole parts constituting each of the one pole and the other pole being changed over time. Since the magnetic field is applied to the magnetic powder, the entire circumferential direction of the magnetic powder can be oriented in the radial direction or the substantially radial direction. Therefore, a ring-shaped magnet excellent in the degree of orientation in the circumferential direction and the uniformity of Br can be obtained. In addition, since magnetic field orientation is performed using a horizontal magnetic field rather than perpendicular to the core, it is not necessary to stack a plurality of molded bodies in order to obtain a long ring magnet. Therefore, a ring-shaped magnet excellent in the degree of orientation in the axial direction (height direction) and the uniformity of Br can be obtained.
さらに、同一極性の少なくとも2個の磁極部の組み合わせを経時的に変化させて磁場を回転させるために、磁極部及びキャビティを移動させる駆動部が必要なく、また、上述の如く、長尺のリング状磁石を得るのに、複数の成形体を積層する必要がなく一度の成形で足りるので、装置構成及び工程を簡略化でき、且つ、工程時間を短縮できる。よって、生産効率を高めることができ、製造コスト及び製品コストを低減することが可能となる。 Further, in order to rotate the magnetic field by changing the combination of at least two magnetic pole portions having the same polarity over time, there is no need for a driving portion for moving the magnetic pole portion and the cavity, and as described above, a long ring In order to obtain a magnet, it is not necessary to stack a plurality of compacts, and only one molding is sufficient. Therefore, the apparatus configuration and the process can be simplified, and the process time can be shortened. Therefore, production efficiency can be increased, and manufacturing costs and product costs can be reduced.
以下、本発明の実施の形態について説明する。なお、同一の要素には同一の符号を付し、重複する説明を省略する。また、上下左右等の位置関係は、特に断らない限り、図面に示す位置関係に基づくものとする。さらに、図面の寸法比率は、図示の比率に限定されるものではない。また、以下の実施の形態は、本発明を説明するための例示であり、本発明はその実施の形態のみに限定されるものではない。 Embodiments of the present invention will be described below. In addition, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios. The following embodiments are examples for explaining the present invention, and the present invention is not limited only to the embodiments.
図1は、本発明によるリング状磁石の製造方法を実施するための好適なリング状磁石成形装置の一例の構成を概略的に示す水平断面図(一部ブロック図、一部上面図)であり、図2は、図1におけるII−II線に沿う垂直断面図である。 FIG. 1 is a horizontal sectional view (partially block diagram, partly top view) schematically showing the structure of an example of a suitable ring-shaped magnet forming apparatus for carrying out the method for producing a ring-shaped magnet according to the present invention. 2 is a vertical sectional view taken along line II-II in FIG.
リング状磁石成形装置100は、架台10上に、金型20が設置される電磁石ユニット30、及びプレス成形ユニット40が設けられたものである。金型20は、磁性粉Mが収容されるキャビティ(内部空間)が画成された中空筒状をなしており、電磁石ユニット30の中央部に設置される。電磁石ユニット30は、金型20のキャビティ内を軸方向に貫通するコア31と、6個の磁極部6a〜6fとを備えている。コア31の材質としては、特に制限されないが、例えばFe−Co合金からなる軟磁性材料が挙げられる。 The ring-shaped magnet forming apparatus 100 is provided with an electromagnet unit 30 on which a mold 20 is installed and a press forming unit 40 on a gantry 10. The mold 20 has a hollow cylindrical shape in which a cavity (internal space) in which the magnetic powder M is accommodated is defined, and is installed at the center of the electromagnet unit 30. The electromagnet unit 30 includes a core 31 that passes through the cavity of the mold 20 in the axial direction, and six magnetic pole portions 6a to 6f. The material of the core 31 is not particularly limited, and examples thereof include a soft magnetic material made of an Fe—Co alloy.
磁極部6a〜6fは、それぞれ、金型20が載置される筒状のダイス33の外周から60°間隔で放射状に延びるヨーク35a〜35fの基幹部に、コイル37a〜37fが設けられたものである。コイル37a〜37fは、それぞれ個別に、制御部50を介して電源60に接続されており、電力(電流)の供給・停止、電力量の調整等が、制御部50の自動又は手動運転により独立して制御可能とされている。なお、ヨーク35a〜35fは、互いに導通している。また、磁極部6a〜6fは、非磁性部材によって架台10上に保持されている。 The magnetic pole portions 6a to 6f are respectively provided with coils 37a to 37f at the base portions of yokes 35a to 35f that extend radially from the outer periphery of the cylindrical die 33 on which the mold 20 is placed at intervals of 60 °. It is. The coils 37a to 37f are individually connected to the power source 60 via the control unit 50, and supply / stop of electric power (current), adjustment of electric energy, etc. are independent by automatic or manual operation of the control unit 50. And can be controlled. The yokes 35a to 35f are electrically connected to each other. Moreover, the magnetic pole parts 6a-6f are hold | maintained on the mount frame 10 by the nonmagnetic member.
また、プレス成形ユニット40は、金型20のキャビティ内に収容された磁性粉Mの上面に当接するように金型20の図示上部に配置された上部パンチ41と、金型20のキャビティ内の磁性粉Mの下面を当接支持するように配置された下部パンチ43とを有している。上部パンチ41は、図示しないアクチュエータ等の駆動機構に接続されており、また、下部パンチ43は、固定又は図示しないアクチュエータ等の駆動機構に接続されており、これらにより、金型20内で磁性粉Mが図示垂直方向にプレスされるようになっている。 In addition, the press molding unit 40 includes an upper punch 41 disposed in the upper part of the mold 20 so as to contact the upper surface of the magnetic powder M accommodated in the cavity of the mold 20, and the cavity 20 of the mold 20. And a lower punch 43 arranged to abut and support the lower surface of the magnetic powder M. The upper punch 41 is connected to a driving mechanism such as an actuator (not shown), and the lower punch 43 is connected to a driving mechanism such as an actuator (not shown) or the like. M is pressed in the vertical direction in the figure.
[第1実施形態]
このように構成されたリング状磁石成形装置100を用いて本発明によるリング状磁石を製造する方法の第1実施形態について、以下に説明する。
[First Embodiment]
A first embodiment of a method for producing a ring-shaped magnet according to the present invention using the thus configured ring-shaped magnet forming apparatus 100 will be described below.
(準備工程)
まず、図1及び図2に示すリング状磁石成形装置100を準備し、図2に示す如く、必要量の磁性粉Mを含むスラリー又は磁性粉Mの顆粒がキャビティ内に収容された金型20を、ヨーク35a〜35fの先端に設置されたダイス33に設置し、コア31、上部パンチ41、下部パンチ43等の周辺部材を適宜配置する。
(Preparation process)
First, a ring-shaped magnet forming apparatus 100 shown in FIGS. 1 and 2 is prepared. As shown in FIG. 2, a mold 20 in which a slurry containing a necessary amount of magnetic powder M or granules of magnetic powder M are accommodated in a cavity. Are placed on a die 33 installed at the tip of the yokes 35a to 35f, and peripheral members such as the core 31, the upper punch 41, the lower punch 43, etc. are appropriately arranged.
ここで、磁性粉Mの材料としては、例えば、R−B−T系(R:希土類元素の1種以上、T:Fe、B:ホウ素)の希土類焼結磁石、特に、Nd−Fe−B系の希土類焼結磁石が好適に用いられ、より具体的には、希土類元素と、希土類元素以外の遷移元素とを組み合わせた組成を有するものが好適である。具体的には、希土類元素Rとして、Nd、Pr及びDyのうちの少なくとも1種を含み、Bを必須元素として1〜12原子%含み、且つ残部がFeであるR−Fe−B系の組成を有するものが好ましい。このような希土類磁石は、必要に応じて、Co、Ni、Mn、Al、Nb、Zr、Ti、W、Mo、V、Ga、Zn、Si等の他の元素を更に含む組成を有していてもよい。なお、希土類磁石は、SmとCoとを含むSm−Co系の組成を有するものであってもよい。 Here, as a material of the magnetic powder M, for example, a rare earth sintered magnet of RBT system (R: one or more of rare earth elements, T: Fe, B: boron), particularly Nd—Fe—B A rare earth sintered magnet is preferably used. More specifically, a rare earth sintered magnet having a combination of a rare earth element and a transition element other than the rare earth element is preferable. Specifically, the rare earth element R includes at least one of Nd, Pr, and Dy, B includes 1 to 12 atomic% as an essential element, and the balance is Fe. Those having the following are preferred. Such a rare earth magnet has a composition further containing other elements such as Co, Ni, Mn, Al, Nb, Zr, Ti, W, Mo, V, Ga, Zn, and Si as required. May be. The rare earth magnet may have an Sm—Co composition containing Sm and Co.
磁性粉Mは、所望の組成を有する希土類磁石が得られるような合金、例えば、希土類磁石の組成に対応する金属等の元素を含む単体、合金や化合物等を、真空又はアルゴン等の不活性ガス雰囲気下で溶解した後、これを用いて鋳造法やストリップキャスト法等の合金製造プロセスを行って作製し、これを粉砕することによって得ることができる。 Magnetic powder M is an alloy from which a rare earth magnet having a desired composition can be obtained, for example, a simple substance containing an element such as a metal corresponding to the composition of the rare earth magnet, an alloy or a compound, or an inert gas such as vacuum or argon. After melting in an atmosphere, it can be obtained by performing an alloy manufacturing process such as a casting method or a strip casting method using this, and pulverizing it.
合金の粉砕は、例えば、ジョークラッシャー、ブラウンミル、スタンプミル等の粗粉砕機を用いるか、または、合金に水素を吸蔵させた後、異なる相間の水素吸蔵量の相違に基づく自己崩壊的な粉砕を生じさせる(水素吸蔵粉砕)ことによって粗粉砕して、数百μm程度の粒径を有する粒子(粗粉体)とした後、その粗粉体に対し、粉砕時間等の条件を適宜調整しながら、ジェットミル、ボールミル、振動ミル、湿式アトライター等の微粉砕機を用いて微粉砕を行い、例えば、10μm以下、より好ましくは1〜10μmの粒径を有する磁性粉Mが得られる。このとき、粉砕性、分散時の分散性並びに成形時の配向性及び潤滑性を向上させるため、潤滑剤或いは分散剤等の粉砕助剤を添加し攪拌しておいてもよい。ここで用いられる粉砕助剤としては、特に限定されるものではないが、例えば、脂肪酸又は脂肪酸の誘導体、炭化水素等を挙げることができる。粉砕助剤の添加量は、特に限定されるものではなく、粗粉体の好ましくは0.01〜0.03質量%程度とされる。 The alloy is pulverized using, for example, a coarse pulverizer such as a jaw crusher, a brown mill, a stamp mill, or the like. The particles (coarse powder) having a particle size of about several hundred μm are roughly pulverized by generating (hydrogen occlusion pulverization), and then the conditions such as the pulverization time are appropriately adjusted for the coarse powder. However, fine pulverization is performed using a fine pulverizer such as a jet mill, a ball mill, a vibration mill, or a wet attritor to obtain a magnetic powder M having a particle size of, for example, 10 μm or less, more preferably 1 to 10 μm. At this time, in order to improve grindability, dispersibility during dispersion, orientation during molding, and lubricity, a grinding aid such as a lubricant or a dispersant may be added and stirred. Although it does not specifically limit as a grinding aid used here, For example, a fatty acid or a derivative of a fatty acid, a hydrocarbon etc. can be mentioned. The addition amount of the grinding aid is not particularly limited, and is preferably about 0.01 to 0.03% by mass of the coarse powder.
さらに、微粉砕された磁性粉Mに適宜の溶媒を添加して混練し、例えば固形分濃度が60〜90質量%程度のスラリーを調製する。かかる溶媒としては、磁石の湿式成形におけるスラリーに用いられる溶媒を特に制限なく適用でき、例えば、鉱物油、合成油、植物油等の油や、アセトン、アルコールといった有機溶媒等が挙げられる。これらのなかでは、磁性粉末の酸化を防ぐために油を用いることが好ましい。或いは、スラリーとせずに公知の手法によって粒径50〜500μm程度の顆粒を作成してもよい。 Furthermore, an appropriate solvent is added to the finely pulverized magnetic powder M and kneaded to prepare, for example, a slurry having a solid content concentration of about 60 to 90% by mass. As such a solvent, a solvent used in a slurry in wet molding of a magnet can be applied without particular limitation, and examples thereof include oils such as mineral oil, synthetic oil and vegetable oil, and organic solvents such as acetone and alcohol. Among these, it is preferable to use oil in order to prevent oxidation of the magnetic powder. Alternatively, granules having a particle size of about 50 to 500 μm may be prepared by a known method without using a slurry.
(磁化工程)
次に、金型20のキャビティ内に収容した磁性粉Mを含むスラリー又は顆粒(以下、単に「磁性粉M」という)の磁場配向(磁化)処理を行う。図3(A)〜(C)は、第1実施形態において、磁性粉Mの磁場配向処理を行っている状態を模式的に示す透過平面図であり、図1における金型20の周辺の要部を示す図である。この磁化工程では、制御部50を運転して、まず、6個の磁極部6a〜6fのうち、互いに隣接する磁極部6b,6cが同一の極性となるように、且つ、それら磁極部6b,6cに対してそれぞれ180°対向する磁極部6e,6fが反対の極性となるように、それぞれに備わるコイル37b,37c,37e,37fに所定の電流(例えば、全て同じ電流)を所定時間通電する。これにより、磁極部6b,6cが一方極として、また、磁極部6e,6fが他方極として機能し、図示実線矢印で模式的に示すような磁束方向を有する磁場が形成される。なお、図示白丸付き矢印及び黒丸付き矢印は、それぞれ一方極及び他方極を構成する各々の磁極部であることを示す(他図において同様とする。)。
(Magnetization process)
Next, a magnetic field orientation (magnetization) treatment is performed on slurry or granules (hereinafter simply referred to as “magnetic powder M”) containing magnetic powder M accommodated in the cavity of the mold 20. FIGS. 3A to 3C are transmission plan views schematically showing a state in which the magnetic field orientation treatment of the magnetic powder M is performed in the first embodiment, and the essential parts around the mold 20 in FIG. FIG. In this magnetization step, the control unit 50 is operated, and among the six magnetic pole parts 6a to 6f, the magnetic pole parts 6b and 6c adjacent to each other have the same polarity, and the magnetic pole parts 6b and 6b, The coils 37b, 37c, 37e, and 37f provided in the respective coils 37b, 37c, 37e, and 37f are energized with a predetermined current (for example, all the same current) for a predetermined time so that the magnetic pole portions 6e and 6f that face each other by 180 ° with respect to 6c have opposite polarities . As a result, the magnetic pole portions 6b and 6c function as one pole and the magnetic pole portions 6e and 6f function as the other pole, and a magnetic field having a magnetic flux direction as schematically shown by the solid line arrows is formed. The white circle arrows and the black circle arrows shown in the figure indicate the respective magnetic pole portions constituting one pole and the other pole (the same applies to other drawings).
ここで、電磁石ユニット30によって印加する磁場の大きさとしては、例えば、12〜20kOe(960〜1600kA/m)程度が挙げられ、さらに、印加する磁場は静磁場に限定されず、パルス状の磁場とすることもでき、静磁場とパルス状磁場を併用することも可能である。 Here, as a magnitude | size of the magnetic field applied by the electromagnet unit 30, about 12-20 kOe (960-1600 kA / m) is mentioned, for example, Furthermore, the magnetic field to apply is not limited to a static magnetic field, A pulse-shaped magnetic field is mentioned. It is also possible to use a static magnetic field and a pulsed magnetic field in combination.
また、このとき、一方極を構成する磁極部6b,6cと他方極を構成する磁極部6e,6fの間に位置する一対の磁極部6a,6dには、電力を供給せず、つまり、磁極として機能させない。これにより、一方極(磁極部6b,6c)によって形成される磁場と、他方極(磁極部6e,6f)によって形成される磁場が、磁極部6a,6dにおいて打ち消し合うので、これら磁極部6a,6dのヨーク先端付近の部位以外の部位に、非常に強力なラジアル方向の磁場が形成される。よって、磁性粉Mの周方向における領域R1,R2(磁極部6a,6dのヨーク先端付近の部位以外に相当する範囲)が十分にラジアル配向される。ここで、図9Aは、図3(A)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。また、図9Bは、同じ結果(原本はカラー図面)を色彩及び濃淡を変えて示した図である。これらより、図3(A)に示す磁極部6b,6cから磁極部6e,6fへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状の強いラジアル方向の磁場(図9Aにおける矢印)が形成されることが確認された。 At this time, no power is supplied to the pair of magnetic pole portions 6a and 6d positioned between the magnetic pole portions 6b and 6c constituting the one pole and the magnetic pole portions 6e and 6f constituting the other pole. Do not function as. Thereby, the magnetic field formed by one pole (magnetic poles 6b and 6c) and the magnetic field formed by the other pole (magnetic poles 6e and 6f) cancel each other out at the magnetic poles 6a and 6d. A very strong radial magnetic field is formed in a portion other than the portion near the tip of the 6d yoke. Therefore, the regions R1 and R2 in the circumferential direction of the magnetic powder M (range corresponding to a portion other than the vicinity of the yoke tips of the magnetic pole portions 6a and 6d) are sufficiently radially oriented. Here, FIG. 9A is a diagram showing a result of visualizing the magnetic field formed in the operation mode shown in FIG. 3A by simulation. FIG. 9B is a diagram showing the same result (original is a color drawing) with different colors and shades. Accordingly, a strong radial magnetic field having a curved shape in which magnetic lines of force enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole parts 6b and 6c shown in FIG. 3A toward the magnetic pole parts 6e and 6f. (Arrow in FIG. 9A) was confirmed to be formed.
また、図3(A)に示す磁場配向処理では、磁極部6a,6dのヨーク先端付近の部位の磁場強度は小さく、且つ、磁性粉Mに対してラジアル方向の磁場が形成されないので、磁性粉Mの周方向における図示領域R3,R4のラジアル配向を行なうべく、図3(A)に示す運転モードによる磁場印加を所定時間実施した後、一方極及び他方極を構成する磁極部の組み合わせを変更して、再度、磁性粉Mの磁場配向処理を行う。具体的には、図3(B)に示す如く、一方極及び他方極を構成する磁極部の組み合わせを、図3(A)に示す状態から、図示時計回りに磁極部2個分ずらすように、すなわち、磁極部6d,6eから一方極を構成し、且つ、磁極部6a,6bから他方極を構成するように、それぞれのコイル37d,37e,37a,37bに、例えば、前回と同電流を同時間通電する。言い換えると、図3(A)に示す運転モードにおける一方極と他方極とで形成される磁場を、時計回りに120°回転させる。 In the magnetic field orientation process shown in FIG. 3 (A), the magnetic field strength in the portion near the tip of the yoke of the magnetic pole portions 6a and 6d is small, and a magnetic field in the radial direction is not formed on the magnetic powder M. In order to perform radial orientation of the illustrated regions R3 and R4 in the circumferential direction of M, after applying a magnetic field in the operation mode shown in FIG. 3A for a predetermined time, the combination of the magnetic pole portions constituting the one pole and the other pole is changed. Then, the magnetic powder M is subjected to magnetic field orientation treatment again. Specifically, as shown in FIG. 3B, the combination of the magnetic pole portions constituting the one pole and the other pole is shifted from the state shown in FIG. 3A by two magnetic pole portions clockwise in the figure. That is, the coils 37d, 37e, 37a, and 37b have the same current as that of the previous time so that the magnetic pole portions 6d and 6e constitute one pole and the magnetic pole portions 6a and 6b constitute the other pole. Energize for the same time. In other words, the magnetic field formed by the one pole and the other pole in the operation mode shown in FIG. 3A is rotated clockwise by 120 °.
このとき、図3(A)に示す運転モードと同様に、一方極を構成する磁極部6d,6eと他方極を構成する磁極部6a,6bの間に位置する一対の磁極部6c,6fには、電力を供給せず、磁極として機能させない。これにより、一方極(磁極部6d,6e)によって形成される磁場と、他方極(磁極部6a,6b)によって形成される磁場が、磁極部6c,6fにおいて打ち消し合うので、これら磁極部6c,6fのヨーク先端付近の部位以外の部位に、非常に強力なラジアル方向の磁場が形成される。これにより、図3(B)に実線矢印で示す如く、前回の磁場印加でラジカル配向されなかった磁性粉Mの周方向における領域R3,R4に、ラジアル方向の強い磁場が印加される。これらの結果、磁性粉Mの周方向全体に亘って均等なラジアル配向が達成される。 At this time, similarly to the operation mode shown in FIG. 3A, the pair of magnetic pole portions 6c and 6f positioned between the magnetic pole portions 6d and 6e constituting one pole and the magnetic pole portions 6a and 6b constituting the other pole are provided. Does not supply power and does not function as a magnetic pole. Thereby, the magnetic field formed by one pole (magnetic poles 6d and 6e) and the magnetic field formed by the other pole (magnetic poles 6a and 6b) cancel each other out at the magnetic poles 6c and 6f. A very strong radial magnetic field is formed in a portion other than the portion near the tip of the yoke 6f. As a result, as indicated by solid arrows in FIG. 3B, a strong magnetic field in the radial direction is applied to the regions R3 and R4 in the circumferential direction of the magnetic powder M that was not radically oriented by the previous magnetic field application. As a result, uniform radial orientation is achieved over the entire circumferential direction of the magnetic powder M.
ここで、図9Cは、図3(B)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。これより、図3(B)に示す磁極部6d,6eから磁極部6a,6bへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状の強いラジアル方向の磁場(図9Cにおける矢印)が形成されることが確認された。 Here, FIG. 9C is a diagram showing a result of visualizing the magnetic field formed in the operation mode shown in FIG. 3B by simulation. Thus, a strong radial magnetic field having a curved shape in which magnetic lines of force enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole portions 6d and 6e shown in FIG. 3B toward the magnetic pole portions 6a and 6b. (Arrow in FIG. 9C) was confirmed to be formed.
また、図3(B)に示す磁極部の組み合わせに代えて、或いは、追加して、図3(C)に示す磁極部の組み合わせを用いて、磁性粉Mに対する磁場印加処理を行ってもよい。この運転モードでは、一方極及び他方極を構成する磁極部の組み合わせを、図3(A)に示す状態から、図示時計回りに磁極部1個分ずらすように、すなわち、磁極部6c,6dから一方極を構成し、且つ、磁極部6f,6aから他方極を構成するように、それぞれのコイル37c,37d,37f,37aに、例えば、前回と同電流を同時間通電する。換言すれば、図3(A)に示す運転モードにおける一方極と他方極とで形成される磁場を、時計回りに60°回転させる。 Further, in place of or in addition to the combination of the magnetic pole portions shown in FIG. 3B, the magnetic field application process may be performed on the magnetic powder M using the combination of the magnetic pole portions shown in FIG. . In this operation mode, the combination of the magnetic pole portions constituting the one pole and the other pole is shifted clockwise by one magnetic pole portion from the state shown in FIG. 3A, that is, from the magnetic pole portions 6c and 6d. Each coil 37c, 37d, 37f, 37a is energized with the same current as the previous time for the same time so as to form one pole and the other pole from the magnetic pole portions 6f, 6a. In other words, the magnetic field formed by the one pole and the other pole in the operation mode shown in FIG. 3A is rotated 60 ° clockwise.
(成形工程)
成形工程は、磁化工程を実施するときに同時に実施することが好ましい。ただし、磁化工程を実施している全時間中実施してもよいし、間欠的に実施しても構わない。この成形工程においては、プレス成形ユニット40を運転し、図示しないアクチュエータ等の駆動装置を駆動して、上部パンチ41及び下部パンチ43間の磁性粉Mに所定の圧力を印加して成形する。このときの成形圧力としては、例えば、0.3〜3ton/cm3(30〜300MPa)が挙げられ、成形開始から終了まで一定であってもよく、漸増又は漸減してもよく、或いは不規則(ランダム)に変化してもよい。成形圧力が低いほど配向度は良好となるが、成形圧力が低すぎると得られる成形体の強度が不足してハンドリング性が低下する傾向にあるので、この点を考慮して上記圧力範囲から成形圧力を適宜選択することができる。
(Molding process)
The forming process is preferably performed simultaneously with the magnetization process. However, it may be performed during the entire time during which the magnetization process is performed, or may be performed intermittently. In this molding step, the press molding unit 40 is operated, and a driving device such as an actuator (not shown) is driven to apply a predetermined pressure to the magnetic powder M between the upper punch 41 and the lower punch 43 for molding. Examples of the molding pressure at this time include 0.3 to 3 ton / cm 3 (30 to 300 MPa), which may be constant from the start to the end of molding, may be gradually increased or gradually decreased, or may be irregular. It may change to (random). The lower the molding pressure, the better the degree of orientation, but if the molding pressure is too low, the resulting molded product will have insufficient strength and the handling property will tend to decrease. The pressure can be appropriately selected.
(焼結工程)
さらに、加圧成形された成形体を、金型20から取り出し、公知の焼結機を用い、真空又は不活性ガス雰囲気中で焼結する。焼結条件は、磁性粉の組成、原料合金の粉砕方法、磁性粉の平均粒径及び粒度分布の相違等、諸条件を考慮して適宜調整され、例えば、1000〜1200℃で1〜10時間程度の焼結が挙げられる。焼結温度が1200℃を超えると結晶粒が異常成長し保持力が低下することがあり、1000℃未満であると焼結体の残留表面磁束密度(Br)が不都合な程度に低下してしまう傾向にある。
(Sintering process)
Further, the pressure-molded molded body is taken out from the mold 20 and sintered in a vacuum or an inert gas atmosphere using a known sintering machine. The sintering conditions are appropriately adjusted in consideration of various conditions such as the composition of the magnetic powder, the raw material alloy pulverization method, the average particle size and the particle size distribution of the magnetic powder, and for example, 1000 to 1200 ° C. for 1 to 10 hours. A degree of sintering. If the sintering temperature exceeds 1200 ° C., crystal grains may grow abnormally and the holding power may decrease. If the sintering temperature is less than 1000 ° C., the residual surface magnetic flux density (Br) of the sintered body will decrease to an inconvenient level. There is a tendency.
(時効処理工程)
それから、得られた焼結体に時効処理を施す。この時効処理は、保磁力(HcJ)を制御する重要な工程であり、常法にしたがって、焼結体を真空又は不活性ガス雰囲気中で熱処理する。時効処理は、2段時効処理とすることが好ましい。2段に分けて行う場合、800℃近傍、600℃近傍での所定時間の保持が有効である。例えば、1段目の時効処理工程では、焼結体を700〜900℃で1〜3時間保持し、その後室温〜200℃の範囲内にまで急冷する第1急冷工程を設けることが好ましい。また、2段目の時効処理工程では、焼結体を500〜700℃で1〜3時間保持し、その後室温まで急冷する第2急冷工程を設けることが好ましい。600℃近傍の熱処理で保磁力が大きく増加するので、時効処理を1段で行なう場合には、600℃近傍の時効処理を施すと好適である。また、R−T−B系焼結磁石を、低R合金と高R合金とを用いる混合法にて作製する場合は、800℃近傍での熱処理を焼結後に行うと、保磁力が増大するので、特に有効である。
(Aging process)
Then, an aging treatment is applied to the obtained sintered body. This aging treatment is an important step for controlling the coercive force (HcJ), and the sintered body is heat-treated in a vacuum or an inert gas atmosphere in accordance with a conventional method. The aging treatment is preferably a two-stage aging treatment. When performing in two stages, holding for a predetermined time in the vicinity of 800 ° C. and 600 ° C. is effective. For example, in the first stage aging treatment step, it is preferable to provide a first quenching step in which the sintered body is held at 700 to 900 ° C. for 1 to 3 hours and then rapidly cooled to a range of room temperature to 200 ° C. Moreover, it is preferable to provide the 2nd quenching process which hold | maintains a sintered compact at 500-700 degreeC for 1 to 3 hours, and then rapidly cools to room temperature in the 2nd stage aging treatment process. Since the coercive force greatly increases by heat treatment near 600 ° C., it is preferable to perform aging treatment near 600 ° C. when the aging treatment is performed in one stage. Further, when an R-T-B sintered magnet is produced by a mixing method using a low R alloy and a high R alloy, the coercive force increases when heat treatment is performed at around 800 ° C. after sintering. So it is especially effective.
以上のようなリング状磁石の製造方法によれば、磁極部6a〜6fのうち隣接する2個の磁極部から一方極を構成し、それらに対向する磁極部から他方極を構成することにより、磁性粉Mの周方向に対してラジアル方向の磁場を印加することができ、それら一方極及び他方極を構成する磁極部の組み合わせを経時的に変化させながら磁場印加を繰り返すことにより、磁性粉Mの周方向全体に亘って均一なラジアル配向を実現することができる。かかる磁性粉Mの周方向全体に亘る均一なラジアル配向は、従来の直線的な水平横磁場の印加処理によって達成することは極めて困難であった。 According to the method for manufacturing a ring magnet as described above, by configuring one pole from two adjacent magnetic pole portions of the magnetic pole portions 6a to 6f and configuring the other pole from the magnetic pole portions facing them, A magnetic field in the radial direction can be applied to the circumferential direction of the magnetic powder M, and the magnetic powder M can be applied by repeating the magnetic field application while changing the combination of the magnetic pole portions constituting the one pole and the other pole over time. Uniform radial orientation can be realized over the entire circumferential direction. Uniform radial orientation over the entire circumferential direction of the magnetic powder M has been extremely difficult to achieve by a conventional linear horizontal transverse magnetic field application process.
ここで、図10A及び図10Bは、それぞれ、円筒状キャビティに収容した磁性粉に対し、4個の磁極部を備える電磁石により従来の直線的な水平横磁場を用いて磁化処理を行ったときに形成される磁場の状態をシミュレーションによって可視化した結果を示す図であり、図10Aは、対向する一対の磁極部を磁極として用い、それらに異なる極性を有する非対向磁場を印加した一例であり、図10Bは、4個の磁極部を全て磁極として用い、磁極対毎に対向磁場を印加した一例である。 Here, FIG. 10A and FIG. 10B show the case where the magnetic powder accommodated in the cylindrical cavity is subjected to magnetization processing using a conventional linear horizontal transverse magnetic field by an electromagnet having four magnetic pole portions. FIG. 10A is a diagram showing a result of visualizing a state of a magnetic field to be formed by simulation, and FIG. 10A is an example in which a pair of opposing magnetic pole portions are used as magnetic poles and non-opposing magnetic fields having different polarities are applied to them. 10B is an example in which all four magnetic pole portions are used as magnetic poles and a counter magnetic field is applied to each magnetic pole pair.
図10Aより、磁極が2つの場合には、図示中央部に示す磁性粉の周囲において、励磁方向(図示左の磁極から右の磁極へ向かう矢印)に対して垂直方向に非常に磁場が弱い部分が生じてしまう。この場合、図示左右の磁極対の正面に相対する部位の磁性粉は強く磁化されるが、その他の部位の磁化は極めて弱くなることが理解される。それから、この励磁方向を90°回転させて図示上下の磁極対を励磁すると、同様にその上下の磁極対の正面に相対する部位の磁性粉が強く磁化される。そうすると、磁極部間に位置する磁性粉の部位は印加磁場が弱いままであり、リング状磁石の残留磁化は周方向に90°間隔で大きく変動してしまう。 10A, when there are two magnetic poles, the magnetic field is very weak in the direction perpendicular to the excitation direction (the arrow from the left magnetic pole to the right magnetic pole in the figure) around the magnetic powder shown in the center of the figure. Will occur. In this case, it is understood that the magnetic powder in the portion facing the front of the left and right magnetic pole pairs shown in the figure is strongly magnetized, but the magnetization in the other portions is extremely weak. Then, when the excitation direction is rotated by 90 ° to excite the upper and lower magnetic pole pairs in the figure, similarly, the magnetic powder at the portion facing the front of the upper and lower magnetic pole pairs is strongly magnetized. If it does so, the site | part of the magnetic powder located between magnetic pole parts will remain with a weak applied magnetic field, and the residual magnetization of a ring-shaped magnet will fluctuate | variate largely by the 90 degree space | interval in the circumferential direction.
一方、図10Bのように4個の磁極を用いて対向磁場を印加すると、磁場を回転させなくても、磁性粉の周方向にある程度の磁化が可能となるが、周方向全体に亘る均等なラジアル配向を達成することは極めて困難であり、また、磁極部間に印加磁場の弱い部分が生じてしまうことを十分に抑制できず、リング状磁石の残留磁化が周方向に90°間隔で大きく変動してしまう傾向が十分に改善できないことが理解される。 On the other hand, when the opposing magnetic field is applied using four magnetic poles as shown in FIG. 10B, a certain amount of magnetization is possible in the circumferential direction of the magnetic powder without rotating the magnetic field, but the entire circumferential direction is evenly distributed. It is extremely difficult to achieve radial alignment, and it is not possible to sufficiently suppress the occurrence of a weak portion of the applied magnetic field between the magnetic pole portions, and the residual magnetization of the ring magnet is large at 90 ° intervals in the circumferential direction. It is understood that the tendency to fluctuate cannot be improved sufficiently.
また、図10A及び図10Bにおいて、磁性粉が収容されたキャビティと電磁石との相対角度配置を45°回転させることにより、上述したリング状磁石の残留磁化における90°間隔の変動が幾分緩和されると推定されるものの、電磁石を回転させたり、キャビティをプレス成形装置等と共に回転させたりするには、装置規模の複雑化及び大型化を招くばかりか、その回転に時間を要する分、生産性が低下してしまう。 Also, in FIGS. 10A and 10B, by rotating the relative angular arrangement of the cavity containing the magnetic powder and the electromagnet by 45 °, the fluctuation of the 90 ° interval in the residual magnetization of the ring-shaped magnet described above is somewhat mitigated. Although it is estimated that rotating the electromagnet and rotating the cavity together with the press molding equipment, etc., not only increase the scale and size of the equipment but also increase the productivity. Will fall.
これに対し、上述した本発明によるリング状磁石の製造方法によれば、電磁石ユニット30や金型20を移動させることなく、しかも、周方向のラジアル配向均一性及びBrの均一性に極めて優れたリング状磁石を得ることができる。また、コアに垂直方向磁場を印加する方式ではないため、リング状磁石の軸方向長さ(高さ)に大きな制約がないので、従来の垂直方向磁場方式を用いた場合に必要であった短尺リング状成形体の成形・積層を行なうことなく、長尺のリング状磁石を一度のプレス成形で製造することができる。よって、リング状磁石の軸方向の配向度及びBrの均一性をも格段に向上させることができ、しかも、生産工程を格別に簡略化することができるので、生産効率及び製造コストを一層低減することができる。 On the other hand, according to the method for manufacturing the ring-shaped magnet according to the present invention described above, the electromagnet unit 30 and the mold 20 are not moved, and the radial radial alignment uniformity and Br uniformity are extremely excellent. A ring-shaped magnet can be obtained. Also, since it is not a method of applying a vertical magnetic field to the core, there is no significant restriction on the axial length (height) of the ring-shaped magnet, so the short length that was necessary when using the conventional vertical magnetic field method A long ring-shaped magnet can be manufactured by a single press molding without molding and laminating the ring-shaped molded body. Therefore, the degree of axial orientation of the ring-shaped magnet and the uniformity of Br can be greatly improved, and the production process can be greatly simplified, further reducing production efficiency and production cost. be able to.
ここで、図8は、本発明のリング状磁石の製造方法によって好適に得られるリング状磁石の一実施形態を示す斜視図である。リング状磁石200は、断面略真円の長尺筒状体であり、軸方向長さLが内径riの1/2よりも大きく且つ一体でプレス成形されたラジアル異方性磁石である。 Here, FIG. 8 is a perspective view showing an embodiment of a ring-shaped magnet suitably obtained by the method for manufacturing a ring-shaped magnet of the present invention. The ring-shaped magnet 200 is a long cylindrical body having a substantially circular cross section, and is a radial anisotropic magnet having an axial length L larger than ½ of the inner diameter r i and integrally press-molded.
このような軸方向長さを有するリング状磁石200は、従来の垂直磁場印加を用いる方法では、短尺成形体を多段に積層しなければ得難いものである。すなわち、図8において、垂直磁場印加によってラジアル方向に十分な強度の磁場を印加できる条件は、下記式(1)で表されるコアの断面積S(≒リング状磁石の内側断面積)と、下記式(2)で表されるリング状磁石200の周壁面積S’とが等しいときであり、このときの軸方向長さLが、垂直磁場印加による1回の磁化によって得られるリング状磁石の軸方向長さの最大値Lmaxとなるので、下記式(3)で表される関係が得られる。下記式中、rOはリング状磁石200の外径を示し、riはリング状磁石200の内径を示す。 The ring-shaped magnet 200 having such an axial length is difficult to obtain unless conventional short magnetic bodies are stacked in a multistage manner by the conventional method using vertical magnetic field application. That is, in FIG. 8, the conditions under which a magnetic field having a sufficient strength in the radial direction can be applied by applying a vertical magnetic field are the cross-sectional area S of the core represented by the following formula (1) (≈the inner cross-sectional area of the ring magnet) This is when the circumferential wall area S ′ of the ring-shaped magnet 200 represented by the following formula (2) is equal, and the axial length L at this time is that of the ring-shaped magnet obtained by one-time magnetization by applying a vertical magnetic field. Since it becomes the maximum value L max of the axial length, the relationship represented by the following formula (3) is obtained. In the following formula, r O represents the outer diameter of the ring-shaped magnet 200, and r i represents the inner diameter of the ring-shaped magnet 200.
このように、軸方向長さLが内径riの1/2よりも大きく且つ一体でプレス成形されたリング状磁石200は、従来の垂直磁場印加による製造方法では得ることができないものである。 As described above, the ring-shaped magnet 200 having the axial length L larger than ½ of the inner diameter r i and integrally press-molded cannot be obtained by a conventional manufacturing method using vertical magnetic field application.
また、前記のとおり、本発明によるリング状磁石は、磁性粉Mの原料の形態や性状、キャビティへの充填状態等の影響を受けるものの、周方向の配向度の変動率が、例えば、好ましくは5%未満、より好ましくは3%未満(磁性粉Mを顆粒として用いた場合等)であり、且つ、軸方向(高さ方向)の配向度の変動率が、例えば、好ましくは2%未満、より好ましくは1%未満のものであって、周方向及び軸方向のいずれの配向度も極めて均一性に優れたものである。すなわち、磁性粉Mの原料形態や性状が同じものを使用した場合、前記従来(1)の方法及び同従来(2)の方法のいずれを用いても、そのように配向度の均一性に優れたリング状磁石200を実現することはできなかった。 Further, as described above, the ring-shaped magnet according to the present invention is affected by the form and properties of the raw material of the magnetic powder M, the filling state of the cavity, etc., but the variation rate of the degree of orientation in the circumferential direction is preferably, for example, Less than 5%, more preferably less than 3% (when the magnetic powder M is used as a granule, etc.), and the variation rate of the degree of orientation in the axial direction (height direction) is, for example, preferably less than 2%, More preferably, it is less than 1%, and the degree of orientation in both the circumferential direction and the axial direction is extremely excellent in uniformity. That is, when the same raw material form and properties of the magnetic powder M are used, the uniformity of the degree of orientation is so excellent regardless of which of the conventional method (1) and the conventional method (2). The ring-shaped magnet 200 could not be realized.
また、図3(A)に戻り、本実施形態のリング状磁石の製造方法によれば、図示の如く、金型20の外周において、一方極及び他方極の各々を構成する2個の磁極部(例えば、磁極部6b,6cの両縁端がなす角度θが、略120°とされているので、これら2個の磁極部6b,6cがカバーする磁性粉Mの周弧の長さが、金型20のキャビティの直径に略等しい。よって、コア31内における磁束密度の飽和を抑止してラジアル配向磁場を大きくできるので、磁性粉Mの周方向における広い範囲で均一性の高いラジアル配向を平易に実現することができる。 Returning to FIG. 3A, according to the method of manufacturing a ring-shaped magnet of the present embodiment, as shown in the figure, two magnetic pole portions constituting each of the one pole and the other pole on the outer periphery of the mold 20. (For example, since the angle θ formed by both edges of the magnetic pole portions 6b and 6c is approximately 120 °, the length of the circumferential arc of the magnetic powder M covered by these two magnetic pole portions 6b and 6c is It is substantially equal to the diameter of the cavity of the mold 20. Therefore, saturation of the magnetic flux density in the core 31 can be suppressed and the radial alignment magnetic field can be increased, so that highly uniform radial alignment can be achieved in a wide range in the circumferential direction of the magnetic powder M. It can be realized easily.
[第2実施形態]
本実施形態では、図1及び図2に示す磁極部6a〜6fに替えて、図4(A)〜(C)に示す120°間隔で離間配置された3個の磁極部3a〜3cを備える電磁石ユニット30を用いること以外は、上述した第1実施形態と同様にしてリング状磁石を製造する。よって、重複する説明を避けるため、磁化工程以外の工程について、ここでの説明は省略する(他の実施形態において同様とする。)。
[Second Embodiment]
In this embodiment, in place of the magnetic pole portions 6a to 6f shown in FIGS. 1 and 2, three magnetic pole portions 3a to 3c arranged at intervals of 120 ° shown in FIGS. 4 (A) to (C) are provided. A ring-shaped magnet is manufactured in the same manner as in the first embodiment described above except that the electromagnet unit 30 is used. Therefore, in order to avoid overlapping description, description here is omitted about steps other than the magnetization step (the same applies to other embodiments).
(磁化工程)
図4(A)〜(C)は、第2実施形態において、磁性粉Mの磁場配向処理を行っている状態を模式的に示す透過平面図であり、図1における金型20の周辺の要部を示す図である。この磁化工程では、まず、3個の磁極部3a〜3cのうち、互いに隣接する磁極部3a,3bが同一の極性となるように、且つ、それら磁極部3a,3bに対向する残りの磁極部3cが反対の極性となるように、それぞれに備わるコイルに所定の電流(例えば、全て同じ電流)を所定時間通電する。
(Magnetization process)
FIGS. 4A to 4C are transmission plan views schematically showing a state in which the magnetic powder M is subjected to the magnetic field orientation treatment in the second embodiment, and the essential parts around the mold 20 in FIG. FIG. In this magnetization process, first, among the three magnetic pole portions 3a to 3c, the remaining magnetic pole portions 3a and 3b that are adjacent to each other have the same polarity and are opposed to the magnetic pole portions 3a and 3b. A predetermined current (for example, all the same current) is energized for a predetermined time to the coils provided in each of the coils so that 3c has the opposite polarity.
これにより、磁極部3a,3bが一方極として機能し、磁極部3cが他方極として機能し、一方極を構成する磁極部3a,3bから、他方極としての磁極部3cへ向かう図示実線矢印で模式的に示すような磁束方向、すなわち、磁性粉Mの周壁に対して略ラジアル方向となる磁場が形成される。このとき、他方極が1個の磁極部3cで構成されるので、磁極部3cには、他の2個の磁極部3a,3bに比して強い磁場が形成され、これにより、磁極部3cの正面部位に相当する磁性粉Mの部位が比較的強く磁化される。ここで、図11は、図4(A)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。これより、図4(A)に示す磁極部3a,3bから磁極部3cへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状をなすラジアル方向の磁場(図11における矢印)が形成されることが確認された。 Thus, the magnetic pole portions 3a and 3b function as one pole, the magnetic pole portion 3c functions as the other pole, and the solid line arrows shown in the figure from the magnetic pole portions 3a and 3b constituting the one pole toward the magnetic pole portion 3c as the other pole. A magnetic field is formed that is substantially in the radial direction with respect to the direction of the magnetic flux as schematically shown, that is, the peripheral wall of the magnetic powder M. At this time, since the other pole is composed of one magnetic pole portion 3c, a magnetic field stronger than the other two magnetic pole portions 3a and 3b is formed in the magnetic pole portion 3c, and thereby the magnetic pole portion 3c. The part of the magnetic powder M corresponding to the front part is relatively strongly magnetized. Here, FIG. 11 is a diagram illustrating a result of visualizing the magnetic field formed in the operation mode illustrated in FIG. As a result, a radial magnetic field having a curved shape in which magnetic lines of force enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole portions 3a and 3b shown in FIG. 11) was confirmed to be formed.
次に、図4(b)及び図4(c)に示すように、一方極及び他方極を構成する磁極部の組み合わせを、順に磁極部1個分ずつ変化させる、すなわち、形成される磁場を順に120°ずつ回転させることにより、3通りの運転モードでの磁場配向処理を実行する。これにより、磁性粉Mの周方向の磁化が平均化され、全体として均等なラジアル配向が実現される。 Next, as shown in FIGS. 4 (b) and 4 (c), the combination of the magnetic pole parts constituting the one pole and the other pole is sequentially changed by one magnetic pole part, that is, the magnetic field to be formed is changed. By rotating in order by 120 °, the magnetic field orientation process in three operation modes is executed. Thereby, the magnetization of the circumferential direction of the magnetic powder M is averaged, and uniform radial orientation is realized as a whole.
[第3実施形態]
本実施形態では、図1及び図2に示す磁極部6a〜6fに替えて、図5(A)〜(C)に示す90°おきに等間隔で離間配置された4個の磁極部4a〜4dを備える電磁石ユニット30を用いること以外は、上述した第1実施形態と同様にしてリング状磁石を製造する。
[Third Embodiment]
In this embodiment, instead of the magnetic pole parts 6a to 6f shown in FIGS. 1 and 2, four magnetic pole parts 4a to 4a spaced apart at equal intervals of 90 ° shown in FIGS. A ring-shaped magnet is manufactured in the same manner as in the first embodiment described above, except that the electromagnet unit 30 having 4d is used.
(磁化工程)
図5(A)〜(C)は、第3実施形態において、磁性粉Mの磁場配向処理を行っている状態を模式的に示す透過平面図であり、図1における金型20の周辺の要部を示す図である。この磁化工程では、まず、4個の磁極部4a〜4dのうち、互いに隣接する磁極部4a,4bが同一の極性となるように、且つ、それら磁極部4a,4bに180°対向配置された残りの磁極部4c,4dが反対の極性となるように、それぞれに備わるコイルに所定の電流(例えば、全て同じ電流)を所定時間通電する。
(Magnetization process)
FIGS. 5A to 5C are transmission plan views schematically showing a state in which the magnetic powder M is subjected to the magnetic field orientation treatment in the third embodiment, and are the essential parts around the mold 20 in FIG. FIG. In this magnetization process, first, among the four magnetic pole portions 4a to 4d, the magnetic pole portions 4a and 4b adjacent to each other have the same polarity, and are arranged to face the magnetic pole portions 4a and 4b by 180 °. A predetermined current (for example, all the same current) is energized for a predetermined time to the coils provided in each of the coils so that the remaining magnetic pole portions 4c and 4d have opposite polarities.
これにより、磁極部4a,4bが一方極として、また、磁極部4c,4dが他方極として機能し、一方極を構成する磁極部4a,4bから、他方極を構成する磁極部4c,4dへ向かう図示実線矢印で模式的に示すような磁束方向、すなわち、磁性粉Mの周壁に対して略ラジアル方向となる磁場が形成される。よって、同極性の磁極部4a,4b間及び磁極部4c,4d間に相当する磁性粉Mの周方向における領域R5,R6が主にラジアル配向される。ここで、図12Aは、図5(A)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。これより、図5(A)に示す磁極部4a,4bから磁極部4c,4dへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状をなすラジアル方向の磁場(図12Aにおける矢印)が形成されることが確認された。 Thereby, the magnetic pole portions 4a and 4b function as one pole, and the magnetic pole portions 4c and 4d function as the other pole, and the magnetic pole portions 4a and 4b constituting the one pole change to the magnetic pole portions 4c and 4d constituting the other pole. A magnetic field is formed in the direction of magnetic flux as schematically shown by the illustrated solid arrow heading, that is, a substantially radial direction with respect to the peripheral wall of the magnetic powder M. Therefore, the regions R5 and R6 in the circumferential direction of the magnetic powder M corresponding to the same polarity between the magnetic pole portions 4a and 4b and between the magnetic pole portions 4c and 4d are mainly radially oriented. Here, FIG. 12A is a diagram showing a result of visualizing the magnetic field formed in the operation mode shown in FIG. Thus, a radial magnetic field having a curved shape in which magnetic lines of force enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole portions 4a and 4b shown in FIG. 5A toward the magnetic pole portions 4c and 4d. (Arrow in FIG. 12A) was confirmed to be formed.
一方、磁極部4a,4d間及び磁極部4b,4c間に相当する部位の磁場強度は小さく、且つ、磁性粉Mに対してラジアル方向の磁場が形成されないので、磁性粉Mの周方向における図示領域R7,R8のラジアル配向を行なうべく、図5(A)に示す運転モードによる磁場印加を所定時間実施した後、一方極及び他方極を構成する磁極部の組み合わせを変更して、再度、磁性粉Mの磁場配向処理を行う。具体的には、図5(B)に示す如く、一方極及び他方極を構成する磁極部の組み合わせを、図5(A)に示す状態から、図示時計回りに磁極部1個分ずらすように、すなわち、磁極部4b,4cから一方極を構成し、且つ、磁極部4d,4aから他方極を構成するように、それぞれのコイルに、例えば、前回と同電流を同時間通電する。つまり、図5(A)に示す運転モードにおける一方極と他方極とで形成される磁場を、時計回りに90°回転させる。これにより、図5(B)に実線矢印で示す如く、前回の磁場印加でラジカル配向されなかった磁性粉Mの周方向における領域R7,R8に、ラジアル方向の磁場が印加される。これらの結果、磁性粉Mの周方向全体に亘って均等なラジアル配向が達成される。 On the other hand, the magnetic field strength in the portion corresponding to between the magnetic pole portions 4a and 4d and between the magnetic pole portions 4b and 4c is small, and a magnetic field in the radial direction is not formed on the magnetic powder M. In order to perform the radial orientation of the regions R7 and R8, after applying the magnetic field in the operation mode shown in FIG. 5 (A) for a predetermined time, the combination of the magnetic pole portions constituting the one pole and the other pole is changed, and the magnetic field is again applied. The magnetic field orientation process of the powder M is performed. Specifically, as shown in FIG. 5B, the combination of the magnetic pole portions constituting the one pole and the other pole is shifted by one magnetic pole portion clockwise from the state shown in FIG. 5A. That is, for example, the same current as that of the previous time is applied to each coil for the same time so that one pole is formed from the magnetic pole portions 4b and 4c and the other pole is formed from the magnetic pole portions 4d and 4a. That is, the magnetic field formed by the one pole and the other pole in the operation mode shown in FIG. 5A is rotated 90 ° clockwise. As a result, as indicated by solid arrows in FIG. 5B, a radial magnetic field is applied to the regions R7 and R8 in the circumferential direction of the magnetic powder M that was not radically oriented by the previous magnetic field application. As a result, uniform radial orientation is achieved over the entire circumferential direction of the magnetic powder M.
ここで、図12Bは、図5(B)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。これより、図5(B)に示す磁極部4b,4cから磁極部4d,4aへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状をなすラジアル方向の磁場(図12Bにおける矢印)が形成されることが確認された。 Here, FIG. 12B is a diagram showing a result of visualizing the magnetic field formed in the operation mode shown in FIG. 5B by simulation. Accordingly, a radial magnetic field having a curved shape in which magnetic lines of force enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole portions 4b and 4c shown in FIG. 5B toward the magnetic pole portions 4d and 4a. (Arrow in FIG. 12B) was confirmed to be formed.
また、図5(B)に示す磁極部の組み合わせに代えて、或いは、追加して、図5(C)に示す磁極部の組み合わせを用いて、磁性粉Mに対する磁場配向処理を行ってもよい。この運転モードでは、一方極及び他方極を構成する磁極部の組み合わせを、図5(A)に示す状態から、図示反時計回りに磁極部1個分ずらすように、すなわち、磁極部4a,4dから一方極を構成し、且つ、磁極部4b,4cから他方極を構成するように、それぞれのコイルに、例えば、前回と同電流を同時間通電する。換言すれば、この運転モードは、図5(A)に示す運転モードにおける一方極と他方極とで形成される磁場を、図示反時計回りに90°回転させたものであり、図5(B)に示す運転モードにおける励磁方向を180°反転させた磁場配向処理に相当する。 Further, in place of or in addition to the combination of the magnetic pole portions shown in FIG. 5B, the magnetic field orientation treatment for the magnetic powder M may be performed using the combination of the magnetic pole portions shown in FIG. . In this operation mode, the combination of the magnetic pole parts constituting the one pole and the other pole is shifted counterclockwise by one magnetic pole part from the state shown in FIG. 5A, that is, the magnetic pole parts 4a and 4d. For example, the same current as that of the previous time is supplied to each coil so as to form one pole from the left and the other pole from the magnetic pole portions 4b and 4c. In other words, this operation mode is obtained by rotating the magnetic field formed by one pole and the other pole in the operation mode shown in FIG. 5A by 90 ° counterclockwise as shown in FIG. This corresponds to a magnetic field orientation process in which the excitation direction in the operation mode shown in FIG.
[第4実施形態]
本実施形態では、図1及び図2に示す磁極部6a〜6fに替えて、図6(A)及び(B)に示す45°間隔で離間配置された8個の磁極部8a〜8hを備える電磁石ユニット30を用い、これらの磁極部8a〜8hのうち隣接する3個の磁極部から一方極及び他方極を構成したこと以外は、上述した第1実施形態と同様にしてリング状磁石を製造する。
[Fourth Embodiment]
In this embodiment, in place of the magnetic pole portions 6a to 6f shown in FIGS. 1 and 2, eight magnetic pole portions 8a to 8h spaced apart at 45 ° intervals shown in FIGS. 6A and 6B are provided. Using the electromagnet unit 30, a ring-shaped magnet is manufactured in the same manner as in the first embodiment described above except that one of the magnetic pole portions 8a to 8h is composed of three adjacent magnetic pole portions and the other pole is formed. To do.
(磁化工程)
図6(A)及び(B)は、第4実施形態において、磁性粉Mの磁場配向処理を行っている状態を模式的に示す透過平面図であり、図1における金型20の周辺の要部を示す図である。この磁化工程では、まず、8個の磁極部8a〜8hのうち、互いに隣接する3個の磁極部8f〜8hが同一の極性となるように、且つ、それら磁極部8f〜8hに対してそれぞれ180°対向する磁極部8b〜8dが反対の極性となるように、それぞれに備わるコイルに所定の電流(例えば、連接する3個のうち中央の磁極部8c,8gに通電する電流を両側の磁極部よりも大きくする)を所定時間通電する。これにより、磁極部8f〜8hが一方極として、また、磁極部8b〜8dが他方極として機能し、図示実線矢印で模式的に示すような磁束方向を有する磁場が形成される。
(Magnetization process)
6 (A) and 6 (B) are transmission plan views schematically showing a state in which the magnetic powder M is subjected to the magnetic field orientation treatment in the fourth embodiment, and the essential parts around the mold 20 in FIG. FIG. In this magnetization process, first, among the eight magnetic pole portions 8a to 8h, the three magnetic pole portions 8f to 8h adjacent to each other have the same polarity, and the magnetic pole portions 8f to 8h respectively. The magnetic poles 8b to 8d facing each other at 180 ° have opposite polarities, and a predetermined current (for example, a current passing through the central magnetic poles 8c and 8g among the three connected to each other) Energized for a predetermined time. As a result, the magnetic pole portions 8f to 8h function as one pole and the magnetic pole portions 8b to 8d function as the other pole, and a magnetic field having a magnetic flux direction schematically shown by a solid line arrow is formed.
また、このとき、一方極を構成する磁極部8f〜8hと他方極を構成する磁極部8b〜8dの間に位置する一対の磁極部8a,8eには、電力を供給せず、磁極として機能させない。これにより、一方極(磁極部8f〜8h)によって形成される磁場と、他方極(磁極部8b〜8d)によって形成される磁場が、磁極部8a,8eにおいて打ち消し合うので、これら磁極部8a,8eのヨーク先端付近の部位以外の部位に、強力なラジアル方向の磁場が形成される。よって、磁性粉Mの周方向における領域R9,R10(磁極部8a,8eのヨーク先端付近の部位以外に相当する範囲)がラジアル配向される。ここで、図13Aは、図6(A)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。これより、図6(A)に示す磁極部8f〜8hから磁極部8b〜8dへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状の強いラジアル方向の磁場(図13Aにおける矢印)が形成されることが確認された。 At this time, power is not supplied to the pair of magnetic pole portions 8a and 8e positioned between the magnetic pole portions 8f to 8h constituting the one pole and the magnetic pole portions 8b to 8d constituting the other pole, and functions as a magnetic pole. I won't let you. Thereby, the magnetic field formed by one pole (magnetic pole portions 8f to 8h) and the magnetic field formed by the other pole (magnetic pole portions 8b to 8d) cancel each other out at the magnetic pole portions 8a and 8e. A strong radial magnetic field is formed at a portion other than the portion near the tip of the yoke 8e. Therefore, the regions R9 and R10 in the circumferential direction of the magnetic powder M (range corresponding to portions other than the portion near the tip of the yoke of the magnetic pole portions 8a and 8e) are radially oriented. Here, FIG. 13A is a diagram showing a result of visualizing the magnetic field formed in the operation mode shown in FIG. 6A by simulation. Thus, a strong radial magnetic field having a curved shape in which magnetic lines of force enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole portions 8f to 8h illustrated in FIG. 6A toward the magnetic pole portions 8b to 8d. (Arrow in FIG. 13A) was confirmed to be formed.
また、図6(A)に示す磁場配向処理では、磁極部8a,8eのヨーク先端付近の部位の磁場強度は小さく、且つ、磁性粉Mに対してラジアル方向の磁場が形成されないので、磁性粉Mの周方向における図示領域R11,R12のラジアル配向を行なうべく、図6(A)に示す運転モードによる磁場印加を所定時間実施した後、一方極及び他方極を構成する磁極部の組み合わせを変更して、再度、磁性粉Mの磁場配向処理を行う。具体的には、図6(B)に示す如く、一方極及び他方極を構成する磁極部の組み合わせを、図6(A)に示す状態から、図示時計回りに磁極部2個分ずらすように、すなわち、磁極部8h,8a,8bから一方極を構成し、且つ、磁極部8d〜8fから他方極を構成するように、それぞれのコイルに、例えば、前回と同電流を同時間通電する。言い換えると、図6(A)に示す運転モードにおける一方極と他方極とで形成される磁場を、時計回りに90°回転させる。 Further, in the magnetic field orientation process shown in FIG. 6A, the magnetic field intensity in the portion near the tip of the yoke of the magnetic pole portions 8a and 8e is small, and a magnetic field in the radial direction is not formed on the magnetic powder M. In order to perform radial alignment of the illustrated regions R11 and R12 in the circumferential direction of M, after applying a magnetic field in the operation mode shown in FIG. 6A for a predetermined time, the combination of the magnetic pole portions constituting the one pole and the other pole is changed. Then, the magnetic powder M is subjected to magnetic field orientation treatment again. Specifically, as shown in FIG. 6 (B), the combination of the magnetic pole parts constituting the one pole and the other pole is shifted from the state shown in FIG. 6 (A) by two magnetic pole parts clockwise in the figure. That is, for example, the same current as that of the previous time is supplied to each coil so as to form one pole from the magnetic pole portions 8h, 8a, and 8b and the other pole from the magnetic pole portions 8d to 8f. In other words, the magnetic field formed by the one pole and the other pole in the operation mode shown in FIG. 6A is rotated 90 ° clockwise.
このとき、図6(A)に示す運転モードと同様に、一方極を構成する磁極部8h,8a,8bと他方極を構成する磁極部8d〜8fの間に位置する一対の磁極部8c,8gには、電力を供給せず、磁極として機能させない。これにより、一方極(磁極部8h,8a,8b)によって形成される磁場と、他方極(磁極部8d〜8f)によって形成される磁場が、磁極部8c,8gにおいて打ち消し合うので、これら磁極部8c,8gのヨーク先端付近の部位以外の部位に、ラジアル方向の磁場が形成される。これにより、図6(B)に実線矢印で示す如く、前回の磁場印加でラジカル配向されなかった磁性粉Mの周方向における領域R11,R12に、ラジアル方向の磁場が印加される。これらの結果、磁性粉Mの周方向全体に亘って均等なラジアル配向が達成される。 At this time, similarly to the operation mode shown in FIG. 6 (A), a pair of magnetic pole portions 8c positioned between the magnetic pole portions 8h, 8a, 8b constituting one pole and the magnetic pole portions 8d-8f constituting the other pole. 8g is not supplied with power and does not function as a magnetic pole. As a result, the magnetic field formed by one pole (magnetic poles 8h, 8a, 8b) and the magnetic field formed by the other pole (magnetic poles 8d-8f) cancel each other out at the magnetic poles 8c, 8g. A magnetic field in the radial direction is formed in a portion other than the portion near the yoke tips of 8c and 8g. As a result, as indicated by solid arrows in FIG. 6B, a radial magnetic field is applied to the regions R11 and R12 in the circumferential direction of the magnetic powder M that was not radically oriented by the previous magnetic field application. As a result, uniform radial orientation is achieved over the entire circumferential direction of the magnetic powder M.
ここで、図13Bは、図6(B)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。これより、図6(B)に示す磁極部8h,8a,8bから磁極部8d〜8fへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状をなすラジアル方向の磁場(図13Bにおける矢印)が形成されることが確認された。なお、磁極部を8個有する本実施形態の製法では、磁極部を6個有する上記実施形態の製法に比して、隣接する磁極部に磁束が漏出してしまう可能性がやや高まる傾向にあり、この点において、磁極部を6個有する上記実施形態の製法がより好適であう。 Here, FIG. 13B is a diagram showing a result of visualizing the magnetic field formed in the operation mode shown in FIG. 6B by simulation. Thus, a radial direction in which the magnetic field lines enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole portions 8h, 8a, and 8b shown in FIG. 6B toward the magnetic pole portions 8d to 8f. It was confirmed that a magnetic field (arrow in FIG. 13B) was formed. In addition, in the manufacturing method of this embodiment having eight magnetic pole portions, there is a tendency that the possibility that the magnetic flux leaks to the adjacent magnetic pole portions is slightly higher than the manufacturing method of the above-described embodiment having six magnetic pole portions. In this respect, the manufacturing method of the above embodiment having six magnetic pole portions is more suitable.
[第5実施形態]
本実施形態では、図1及び図2に示す磁極部6a〜6fに替えて、図7(A)及び(B)に示す45°間隔で離間配置された8個の磁極部8a〜8hを備える電磁石ユニット30を用いたこと以外は、上述した第1実施形態と同様にしてリング状磁石を製造する。
[Fifth Embodiment]
In this embodiment, instead of the magnetic pole portions 6a to 6f shown in FIGS. 1 and 2, eight magnetic pole portions 8a to 8h spaced apart at 45 ° intervals shown in FIGS. 7A and 7B are provided. A ring-shaped magnet is manufactured in the same manner as in the first embodiment described above except that the electromagnet unit 30 is used.
(磁化工程)
図7(A)及び(B)は、第5実施形態において、磁性粉Mの磁場配向処理を行っている状態を模式的に示す透過平面図であり、図1における金型20の周辺の要部を示す図である。この磁化工程では、まず、8個の磁極部8a〜8hのうち、互いに隣接する2個の磁極部8f,8gが同一の極性となるように、且つ、それら磁極部8f,8gに対してそれぞれ180°対向する磁極部8b,8cが反対の極性となるように、それぞれに備わるコイルに所定の電流(例えば、同電流)を所定時間通電する。これにより、磁極部8f,8gが一方極として、また、磁極部8b,8cが他方極として機能し、図示実線矢印で模式的に示すような磁束方向を有する磁場が形成される。
(Magnetization process)
FIGS. 7A and 7B are transmission plan views schematically showing a state in which the magnetic powder M is subjected to the magnetic field orientation treatment in the fifth embodiment. FIG. In this magnetization step, first, of the eight magnetic pole portions 8a to 8h, the two magnetic pole portions 8f and 8g adjacent to each other have the same polarity, and with respect to the magnetic pole portions 8f and 8g, respectively. A predetermined current (for example, the same current) is energized for a predetermined time to the coils provided in each of the coils so that the magnetic pole portions 8b and 8c facing each other at 180 ° have opposite polarities. As a result, the magnetic pole portions 8f and 8g function as one pole and the magnetic pole portions 8b and 8c function as the other pole, and a magnetic field having a magnetic flux direction as schematically shown by the solid line arrows is formed.
また、このとき、一方極を構成する磁極部8f,8gと他方極を構成する磁極部8b,8cとの間に位置する二対の磁極部8a,8e及び磁極部8h,8dには、電力を供給せず、磁極として機能させない。この場合、通電しない磁極部が2個隣り合う状態となるので、それらの磁極部8a,8d,8e,8hには弱いながらも磁束が通っており磁場印加効率が若干低下するものの、磁極部8a,8d,8e,8hのヨーク先端付近の部位以外の部位に、ラジアル方向の磁場が形成される。よって、磁性粉Mの周方向における領域R13,R14(磁極部8a,8d,8e,8hのヨーク先端付近の部位以外に相当する範囲)がラジアル配向される。ここで、図14Aは、図7(A)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。これより、図7(A)に示す磁極部8f,8gから磁極部8b,8cへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状をなすラジアル方向の磁場(図14Aにおける矢印)が形成されることが確認された。 At this time, the two pairs of magnetic pole portions 8a and 8e and the magnetic pole portions 8h and 8d positioned between the magnetic pole portions 8f and 8g constituting the one pole and the magnetic pole portions 8b and 8c constituting the other pole Is not supplied and does not function as a magnetic pole. In this case, since two magnetic pole portions that are not energized are adjacent to each other, the magnetic pole portions 8a, 8d, 8e, and 8h are weak but magnetic flux passes therethrough, but the magnetic field application efficiency is slightly reduced, but the magnetic pole portion 8a. , 8d, 8e, and 8h, a radial magnetic field is formed at a portion other than the portion near the tip of the yoke. Therefore, the regions R13 and R14 in the circumferential direction of the magnetic powder M (ranges corresponding to portions other than the portion near the tip of the yoke of the magnetic pole portions 8a, 8d, 8e, and 8h) are radially oriented. Here, FIG. 14A is a diagram showing the result of visualizing the magnetic field formed in the operation mode shown in FIG. 7A by simulation. Thus, a radial magnetic field having a curved shape in which magnetic lines of force enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole portions 8f and 8g shown in FIG. 7A toward the magnetic pole portions 8b and 8c. (Arrow in FIG. 14A) was confirmed to be formed.
また、図7(A)に示す磁場配向処理では、磁極部8a,8d,8e,8hのヨーク先端付近の部位の磁場強度は小さく、且つ、磁性粉Mに対してラジアル方向の磁場が形成されないので、磁性粉Mの周方向における図示領域R15,R16のラジアル配向を行なうべく、図7(A)に示す運転モードによる磁場印加を所定時間実施した後、一方極及び他方極を構成する磁極部の組み合わせを変更して、再度、磁性粉Mの磁場配向処理を行う。具体的には、図7(B)に示す如く、一方極及び他方極を構成する磁極部の組み合わせを、図7(A)に示す状態から、図示反時計回りに磁極部2個分ずらすように、すなわち、磁極部8d,8eから一方極を構成し、且つ、磁極部8h,8aから他方極を構成するように、それぞれのコイルに、例えば、前回と同電流を同時間通電する。言い換えると、図7(A)に示す運転モードにおける一方極と他方極とで形成される磁場を、反時計回りに90°回転させる。 In addition, in the magnetic field orientation process shown in FIG. 7A, the magnetic field strength in the portion near the tip of the yoke of the magnetic pole portions 8a, 8d, 8e, and 8h is small, and a magnetic field in the radial direction is not formed on the magnetic powder M. Therefore, in order to perform the radial orientation of the illustrated regions R15 and R16 in the circumferential direction of the magnetic powder M, the magnetic pole portions constituting the one pole and the other pole after the magnetic field application in the operation mode shown in FIG. The magnetic powder M is subjected to the magnetic field orientation treatment again. Specifically, as shown in FIG. 7B, the combination of the magnetic pole parts constituting the one pole and the other pole is shifted counterclockwise by two magnetic pole parts from the state shown in FIG. 7A. In other words, for example, the same current as that of the previous time is applied to each coil for the same time so that one pole is formed from the magnetic pole portions 8d and 8e and the other pole is formed from the magnetic pole portions 8h and 8a. In other words, the magnetic field formed by the one pole and the other pole in the operation mode shown in FIG. 7A is rotated 90 ° counterclockwise.
このとき、図7(A)に示す運転モードと同様に、一方極を構成する磁極部8d,8eと他方極を構成する磁極部8h,8aとの間に位置する二対の磁極部8b,8f及び磁極部8c,8gには、電力を供給せず、磁極として機能させない。この場合も、通電しない磁極部が2個隣り合う状態となるので、それらの磁極部8b,8f,8c,8gには弱いながらも磁束が通っており磁場印加効率が若干低下するものの、磁極部8b,8f,8c,8gのヨーク先端付近の部位以外の部位に、ラジアル方向の磁場が形成される。これにより、図7(B)に実線矢印で示す如く、前回の磁場印加でラジカル配向されなかった磁性粉Mの周方向における領域R15,R16に、ラジアル方向の磁場が印加される。これらの結果、磁性粉Mの周方向全体に亘って均等なラジアル配向が達成される。 At this time, similarly to the operation mode shown in FIG. 7 (A), two pairs of magnetic pole portions 8b, 8b, 8e that constitute one pole and magnetic pole portions 8h, 8a that constitute the other pole, 8f and the magnetic pole portions 8c and 8g are not supplied with power and do not function as magnetic poles. Also in this case, since two magnetic pole portions that are not energized are adjacent to each other, the magnetic pole portions 8b, 8f, 8c, and 8g are weak but magnetic flux passes therethrough, but the magnetic field application efficiency is slightly reduced. A magnetic field in the radial direction is formed at a portion other than the portion near the yoke tip of 8b, 8f, 8c, and 8g. As a result, as indicated by solid arrows in FIG. 7B, a radial magnetic field is applied to the regions R15 and R16 in the circumferential direction of the magnetic powder M that was not radically oriented by the previous magnetic field application. As a result, uniform radial orientation is achieved over the entire circumferential direction of the magnetic powder M.
ここで、図14Bは、図7(B)に示す運転モードで形成される磁場をシミュレーションによって可視化した結果を示す図である。これより、図7(B)に示す磁極部8d,8eから磁極部8h,8aへ向かって、金型20の周壁に対して磁力線が垂直に入出射するような曲線状をなすラジアル方向の磁場(図14Bにおける矢印)が形成されることが確認された。 Here, FIG. 14B is a diagram showing a result of visualizing the magnetic field formed in the operation mode shown in FIG. 7B by simulation. Thus, a radial magnetic field having a curved shape in which magnetic lines of force enter and exit perpendicularly to the peripheral wall of the mold 20 from the magnetic pole portions 8d and 8e shown in FIG. 7B toward the magnetic pole portions 8h and 8a. (Arrow in FIG. 14B) was confirmed to be formed.
なお、上述したとおり、本発明は、上記各実施形態に限定されるものではなく、その要旨を逸脱しない範囲内において適宜変更を加えることが可能である。例えば、各実施形態における一方極と他方極とを入れ替えて励磁方向を反転させてもよい。また、磁化工程においては、一方極及び他方極の各々の磁極部の組み合わせを変化させた各磁場配向処理を交互に複数回繰り返し実施してもよい。さらに、電磁石ユニット30に備わる磁極部の数は、3個以上であれば各実施形態に記載された数に限定されないが、磁性粉Mの周方向全体のラジアル配向の均一性及び磁場強度を最も高め易い観点から、図3(A)〜(C)に示す如く、形状構成の6個の磁極部6a〜6fを備えたリング状磁石成形装置100における運転方法が望ましい。 In addition, as above-mentioned, this invention is not limited to said each embodiment, In the range which does not deviate from the summary, it can add suitably. For example, the excitation direction may be reversed by exchanging one pole and the other pole in each embodiment. Further, in the magnetization step, each magnetic field orientation process in which the combination of the magnetic pole portions of the one pole and the other pole is changed may be alternately repeated a plurality of times. Further, the number of magnetic pole portions provided in the electromagnet unit 30 is not limited to the number described in each embodiment as long as it is three or more. However, the uniformity of the radial orientation in the entire circumferential direction of the magnetic powder M and the magnetic field strength are the highest. From the viewpoint of easy improvement, an operation method in the ring-shaped magnet forming apparatus 100 including the six magnetic pole portions 6a to 6f having the shape and configuration as shown in FIGS. 3 (A) to (C) is desirable.
以下、実施例により本発明を詳細に説明するが、本発明はこれらに限定されるものではない。 EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
〈実施例1〉
3個の磁極部を有する電磁石ユニットを備えるリング状磁石成形装置100を用い、第2実施形態におけるリング状磁石の製造方法と同様(磁性粉Mとして顆粒を用いた)にして、内径ri=34mm、外径ro=40mm、軸方向長さL=40mmのリング状磁石200を作製した。
<Example 1>
Using a ring-shaped magnet forming apparatus 100 including an electromagnet unit having three magnetic pole portions, in the same manner as the method for manufacturing a ring-shaped magnet in the second embodiment (using granules as the magnetic powder M), the inner diameter r i = A ring-shaped magnet 200 having a diameter of 34 mm, an outer diameter r o = 40 mm, and an axial length L = 40 mm was produced.
〈実施例2〉
4個の磁極部を有する電磁石ユニットを備えるリング状磁石成形装置100を用い、第3実施形態におけるリング状磁石の製造方法と同様にしたこと以外は、実施例1と同様にしてリング状磁石200を作製した。
<Example 2>
A ring-shaped magnet 200 is formed in the same manner as in Example 1 except that a ring-shaped magnet forming apparatus 100 including an electromagnet unit having four magnetic pole portions is used and the manufacturing method is the same as that of the third embodiment. Was made.
〈実施例3〉
6個の磁極部を有する電磁石ユニットを備えるリング状磁石成形装置100を用い、第1実施形態におけるリング状磁石の製造方法と同様にしたこと以外は、実施例1と同様にしてリング状磁石200を作製した。
<Example 3>
A ring-shaped magnet 200 is used in the same manner as in Example 1 except that the ring-shaped magnet forming apparatus 100 including an electromagnet unit having six magnetic pole portions is used and the manufacturing method is the same as that of the first embodiment. Was made.
〈実施例4〉
8個の磁極部を有する電磁石ユニットを備えるリング状磁石成形装置100を用い、第4実施形態におけるリング状磁石の製造方法と同様にしたこと以外は、実施例1と同様にしてリング状磁石200を作製した。
<Example 4>
A ring-shaped magnet 200 is used in the same manner as in Example 1 except that a ring-shaped magnet forming apparatus 100 including an electromagnet unit having eight magnetic pole portions is used and the manufacturing method is the same as that of the fourth embodiment. Was made.
〈比較例1〉
実施例1の磁化工程に替えて、2個の磁極部を備える電磁石ユニットにより従来の直線的な水平横磁場を用い、励磁方向が90°異なる2種類の磁化処理を行ったこと以外は、実施例1と同様にしてリング状磁石を作製した。
<Comparative example 1>
Instead of the magnetizing process of the first embodiment, an electromagnet unit having two magnetic pole portions is used except that a conventional linear horizontal transverse magnetic field is used, and two types of magnetization processes with different excitation directions are performed by 90 °. A ring-shaped magnet was produced in the same manner as in Example 1.
〈比較例2〉
磁性粉がリング状に収容される円筒状キャビティを軸方向に貫通する軟磁性コアに垂直方向磁場を印加し、軟磁性コアの外周に配置した軟磁性ダイを通る磁束を発生させて、キャビティ内の磁性粉をラジアル方向に配向させた状態でプレス成形する上記従来(1)方法を用い、短尺のリング状成形体を3層積層プレスすることにより、実施例1と同組成及び同形状のリング状磁石を作製した。
<Comparative example 2>
A vertical magnetic field is applied to a soft magnetic core that passes through a cylindrical cavity that contains a magnetic powder in a ring shape in the axial direction, and a magnetic flux is generated through a soft magnetic die disposed on the outer periphery of the soft magnetic core to generate A ring having the same composition and shape as in Example 1 is obtained by using the above-mentioned conventional method (1), in which the magnetic powder is oriented in the radial direction, and laminating a short ring-shaped molded body by three layers. A magnet was produced.
〈物性評価〉
(周方向の配向度測定)
上記各実施例及び各比較例で作製した各リング状磁石の軸方向長さ中心において、X線回折装置(株式会社リガク製;製品名 RINT2000;スリット幅0.1mm)を用いて周方向における配向度分布を全周に亘って測定した。図15に、実施例1〜4及び比較例1,2で作製した各リング状磁石の周方向における配向度分布(15°毎の配向度の測定値)のグラフを示す。同図中、実線は各実施例及び各比較例のリング状磁石の周方向における配向度測定値をプロットしたシンボルを結ぶ平滑化した目安線であり、実線E1〜E4、及び実線C1,C2は、それぞれ、実施例1〜4及び比較例1,2のリング状磁石の配向度分布を示す。また、表1に、それらの測定値から求めた配向度(%)に関する統計量(標準偏差、平均値、変動率)をまとめて示す。
<Evaluation of the physical properties>
(Measurement of circumferential orientation)
Orientation in the circumferential direction using an X-ray diffractometer (manufactured by Rigaku Corporation; product name RINT2000; slit width 0.1 mm) at the center of the axial length of each ring magnet produced in each of the above examples and comparative examples. The degree distribution was measured over the entire circumference. In FIG. 15, the graph of the orientation degree distribution (measured value of orientation degree for every 15 degrees) in the circumferential direction of each ring-shaped magnet produced in Examples 1-4 and Comparative Examples 1 and 2 is shown. In the figure, the solid line is a smoothed reference line connecting symbols in which the orientation degree measurement values in the circumferential direction of the ring magnets of each Example and each Comparative Example are plotted, and the solid lines E1 to E4 and the solid lines C1 and C2 are These show the orientation degree distributions of the ring magnets of Examples 1 to 4 and Comparative Examples 1 and 2, respectively. Table 1 summarizes the statistics (standard deviation, average value, rate of change) regarding the degree of orientation (%) obtained from these measured values.
これらの結果より、実施例1〜4のリング状磁石では、周方向の配向度の変動率がいずれも3%未満であり、配向度の周方向の角度ばらつきが非常に小さく、しかも、比較例に比してラジアル方向の配向度が高いことが判明した。特に、実施例3のリング状磁石(6個の磁極部で磁場配向したもの)の優位性が理解される。これに対し、比較例1のリング状磁石は、90°周期で配向度が大きく変動することが確認された。 From these results, in the ring-shaped magnets of Examples 1 to 4, the variation rate of the orientation degree in the circumferential direction is less than 3%, the angular variation in the circumferential direction of the orientation degree is very small, and the comparative example It was found that the degree of orientation in the radial direction was higher than that of. In particular, the superiority of the ring-shaped magnet of Example 3 (the magnetic field is oriented by six magnetic pole portions) is understood. On the other hand, it was confirmed that the degree of orientation of the ring-shaped magnet of Comparative Example 1 greatly fluctuated with a 90 ° period.
(軸方向の配向度測定)
上記各実施例及び各比較例で作製した各リング状磁石の周方向の任意位置において、上記と同じX線回折装置を用いて軸方向における配向度分布を全長に亘って測定した。図16に、実施例3及び比較例1,2で作製した各リング状磁石の軸方向における配向度分布(2mm毎の配向度の測定値)のグラフを示す。同図中、実線は実施例3及び比較例1,2のリング状磁石の軸方向における配向度測定値をプロットしたシンボルを結ぶ平滑化した目安線であり、実線E3及び実線C1,C2は、それぞれ、実施例1及び比較例1,2のリング状磁石の配向度分布を示す。また、表2に、それらの測定値から求めた配向度(%)に関する統計量(標準偏差、平均値、変動率)をまとめて示す。
(Measurement of axial orientation)
The orientation degree distribution in the axial direction was measured over the entire length using the same X-ray diffractometer as described above at an arbitrary position in the circumferential direction of each ring-shaped magnet produced in each of the above Examples and Comparative Examples. In FIG. 16, the graph of the orientation degree distribution (measured value of orientation degree for every 2 mm) of each ring-shaped magnet produced in Example 3 and Comparative Examples 1 and 2 is shown. In the figure, the solid line is a smoothed reference line connecting symbols plotting the orientation degree measurement values in the axial direction of the ring magnets of Example 3 and Comparative Examples 1 and 2, and the solid line E3 and the solid lines C1 and C2 are: The orientation degree distributions of the ring magnets of Example 1 and Comparative Examples 1 and 2 are shown, respectively. Table 2 summarizes the statistics (standard deviation, average value, rate of change) regarding the degree of orientation (%) obtained from these measured values.
これらの結果より、実施例3のリング状磁石(6個の磁極部で磁場配向したもの)は、軸方向の配向度の乱れも少なく、その変動率は1%未満であることが確認された。これに対し、比較例2のリング状磁石は、積層界面における配向度の変動が有意に大きいことが確認された。 From these results, it was confirmed that the ring-shaped magnet of Example 3 (magnetic field oriented with six magnetic pole portions) had little disturbance in the degree of orientation in the axial direction and the variation rate was less than 1%. . In contrast, the ring-shaped magnet of Comparative Example 2 was confirmed to have a significantly large variation in the degree of orientation at the laminated interface.
以上説明した通り、本発明のリング状磁石及びその製造方法によれば、円周方向及び軸方向における配向度及びBrの均一性を共に向上させることができ、これによりモータに用いたときのトルクリプル及びコギングトルクの発生を十分に防止できるとともに、生産効率及び経済性を高めることができ量産性に資することが可能であるので、リング状の永久磁石用途一般、及びこれを備えるSPMモータ等のモータ一般、並びにそれらを備える各種機器、設備、システム等に広く且つ有効に利用可能である。 As described above, according to the ring-shaped magnet and the manufacturing method thereof of the present invention, both the degree of orientation in the circumferential direction and the axial direction and the uniformity of Br can be improved, and thus the torque ripple when used in a motor. In addition, the generation of cogging torque can be sufficiently prevented, and the production efficiency and economy can be improved, which can contribute to mass productivity. Therefore, ring-shaped permanent magnets are generally used, and motors such as SPM motors including the same. It can be widely and effectively used in general, as well as various devices, facilities, systems and the like equipped with them.
3a〜3c、4a〜4d、6a〜6f、8a〜8h…磁極部、10…架台、20…金型、30…電磁石ユニット、31…コア、33…ダイス、35a〜35f…ヨーク、37a〜37f…コイル、40…プレス成形ユニット、41…上部パンチ、43…下部パンチ、50…制御部、60…電源、100…リング状磁石成形装置、200…リング状磁石、L…軸方向長さ、M…磁性粉、R1〜R16…領域、ri…内径、ro…外径、θ…角度。 3a to 3c, 4a to 4d, 6a to 6f, 8a to 8h ... magnetic pole part, 10 ... mount, 20 ... mold, 30 ... electromagnet unit, 31 ... core, 33 ... dice, 35a to 35f ... yoke, 37a to 37f DESCRIPTION OF SYMBOLS ... Coil, 40 ... Press molding unit, 41 ... Upper punch, 43 ... Lower punch, 50 ... Control part, 60 ... Power supply, 100 ... Ring-shaped magnet molding apparatus, 200 ... Ring-shaped magnet, L ... Axial length, M ... magnetic powder, R1 to R16 ... region, r i ... inner diameter, r o ... outer diameter, θ ... angle.
Claims (7)
前記3個以上の磁極部のうち互いに隣接する少なくとも2個の磁極部を同一の極性として一方極を構成し、前記3個以上の磁極部のうち該一方極と対向する少なくとも1個の磁極部を反対の極性として他方極を構成し、且つ、前記キャビティに収容された前記磁性粉の周方向全体に亘ってラジアル方向又は略ラジアル方向の磁場が印加されるように、前記一方極及び前記他方極の各々を構成する磁極部の組み合わせを経時的に変化させながら、前記キャビティに収容された磁性粉に磁場を印加する磁化工程と、
前記キャビティに収容された前記磁性粉を加圧成形する成形工程と、
を有するリング状磁石の製造方法。 A preparatory step of preparing an electromagnet comprising a core portion made of a soft magnetic material that penetrates the inside of a cylindrical cavity in the axial direction and three or more magnetic pole portions arranged at predetermined angular intervals along the outer periphery of the cavity When,
Among the three or more magnetic pole portions, at least two magnetic pole portions adjacent to each other have the same polarity to form one pole, and among the three or more magnetic pole portions, at least one magnetic pole portion facing the one pole And the other pole so that a magnetic field in a radial direction or a substantially radial direction is applied over the entire circumferential direction of the magnetic powder accommodated in the cavity. A magnetization step of applying a magnetic field to the magnetic powder accommodated in the cavity while changing a combination of magnetic pole portions constituting each of the poles over time;
A molding step of pressure-molding the magnetic powder accommodated in the cavity;
The manufacturing method of the ring-shaped magnet which has this.
請求項1記載のリング状磁石の製造方法。 As the electromagnet, one having an even number of the magnetic pole portions is used.
The manufacturing method of the ring-shaped magnet of Claim 1.
前記磁化工程においては、前記4個の磁極部のうち隣接する2個の磁極部を同一の極性として前記一方極を構成し、且つ、該一方極の2個の磁極部と対向する2個の磁極部を反対の極性として前記他方極を構成した状態で、前記磁性粉に磁場を印加した後、該一方極及び該他方極の各々の2個の磁極部の組み合わせを周方向に磁極部1個分変化させた状態で、前記磁性粉に磁場を印加する、
請求項2記載のリング状磁石の製造方法。 Using the electromagnet having four magnetic pole portions arranged at 90 ° or substantially 90 ° intervals along the outer periphery of the cavity,
In the magnetization step, the one pole is configured with the two adjacent magnetic pole portions of the four magnetic pole portions having the same polarity, and the two magnetic pole portions facing the two magnetic pole portions of the one pole After applying the magnetic field to the magnetic powder in the state where the other pole is configured with the magnetic pole part having the opposite polarity, the combination of the two magnetic pole parts of each of the one pole and the other pole is arranged in the circumferential direction. Applying a magnetic field to the magnetic powder in a state where the amount is changed,
The manufacturing method of the ring-shaped magnet of Claim 2.
前記磁化工程においては、前記6個の磁極部のうち隣接する2個の磁極部を同一の極性として前記一方極を構成し、且つ、該一方極の2個の磁極部と対向する2個の磁極部を反対の極性として前記他方極を構成した状態で、前記磁性粉に磁場を印加した後、該一方極及び該他方極の各々の2個の磁極部の組み合わせを周方向に磁極部1個分又は2個分変化させた状態で、前記磁性粉に磁場を印加する、
請求項2記載のリング状磁石の製造方法。 As the electromagnet, one having six magnetic pole portions arranged at intervals of 60 ° or approximately 60 ° along the outer periphery of the cavity is used.
In the magnetization step, the two poles adjacent to each other among the six pole parts are configured to have the same polarity, and the one pole is formed, and two pole parts facing the two pole parts of the one pole are formed. After applying the magnetic field to the magnetic powder in the state where the other pole is configured with the magnetic pole part having the opposite polarity, the combination of the two magnetic pole parts of each of the one pole and the other pole is arranged in the circumferential direction. Applying a magnetic field to the magnetic powder in a state of being changed by one piece or two pieces,
The manufacturing method of the ring-shaped magnet of Claim 2.
前記磁化工程においては、前記8個の磁極部のうち隣接する2個又は3個の磁極部を同一の極性として前記一方極を構成し、且つ、該一方極の2個又は3個の磁極部と対向する2個又は3個の磁極部を反対の極性として前記他方極を構成した状態で、前記磁性粉に磁場を印加した後、該一方極及び他方極の各々の2個又は3個の磁極部の組み合わせを周方向に磁極部1個分、2個分、又は3個分変化させた状態で、前記磁性粉に磁場を印加する、
請求項2記載のリング状磁石の製造方法。 As the electromagnet, one provided with the eight magnetic pole portions arranged at 45 ° or substantially 45 ° intervals along the outer periphery of the cavity,
In the magnetization step, two or three adjacent magnetic pole portions of the eight magnetic pole portions have the same polarity to form the one pole, and the two or three magnetic pole portions of the one pole After applying the magnetic field to the magnetic powder in a state where the other pole is configured with two or three magnetic pole portions opposite to each other having the opposite polarity, two or three of each of the one pole and the other pole A magnetic field is applied to the magnetic powder in a state where the combination of the magnetic pole portions is changed by one magnetic pole portion, two pieces, or three in the circumferential direction.
The manufacturing method of the ring-shaped magnet of Claim 2.
前記磁化工程においては、前記一方極と前記他方極との間に対向配置された少なくとも1対の磁極部に電力を供給しない、
請求項2記載のリング状磁石の製造方法。 As the electromagnet, one having at least six magnetic pole portions is used,
In the magnetization step, power is not supplied to at least one pair of magnetic pole portions disposed to face each other between the one pole and the other pole.
The manufacturing method of the ring-shaped magnet of Claim 2.
請求項1〜6のいずれか1項記載のリング状磁石の製造方法。 As the electromagnet, an outer periphery of the cavity having an angle formed by both edges of the one pole and / or the other pole of approximately 120 ° is used.
The manufacturing method of the ring-shaped magnet of any one of Claims 1-6.
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CN107045931A (en) * | 2016-02-06 | 2017-08-15 | 宁波火山电气有限公司 | Magnetic base manufacturing equipment and magnetic base manufacture method |
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