JP3664271B2 - Multipolar magnetizing yoke - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a magnetizing yoke for a permanent magnet member, and more particularly to a magnetizing yoke for multipolarizing a ring magnet or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, ring-shaped or cylindrical permanent magnets magnetized in the radial direction have been used for rotors and stators of electric motors. For example, when a ring-shaped permanent magnet (hereinafter also simply referred to as a ring magnet) is magnetized in a multipolar manner, a magnetizing yoke 101 as shown in FIG. 1 is used. The magnetizing yoke 101 is formed in a cylindrical shape by, for example, electromagnetic soft iron, and a plurality of mounting grooves 104 are formed in parallel along the axial direction on the inner peripheral surface of the hole 102. Further, as shown in FIG. 3, the exciting coil wire 105 is mounted while being folded back on the end portion side of the yoke 101 across all of the mounting grooves 104. Then, the ring magnet 103 is arranged concentrically in the hole portion 102, and the coil wire 105 is energized, so that as shown in FIG. Polarized.
[0003]
[Problems to be solved by the invention]
By the way, the ring magnet 103 as described above has recently been formed of a rare earth magnet material such as an Nd—Fe—B magnet material or an Sm—Co magnet material in order to reduce the size or performance of the motor. Many things are used. Since the rare earth magnet material has an extremely large coercive force, it is necessary to apply a large magnetizing magnetic field to overcome it in order to achieve sufficient magnetization. However, in the conventional magnetizing yoke, it is difficult to say that the saturation magnetic flux density and magnetic permeability of the constituent soft magnetic iron are necessarily sufficient for magnetizing rare earth magnets. Is insufficient, and there is a problem that surface magnetic flux density is insufficient and bias (so-called uneven magnetization) is likely to occur. In particular, as shown in FIG. 8A, the surface magnetic flux density of the magnet 103 tends to be insufficient on the side where the folded portion 106 of the coil wire 105 is not formed compared to the side where the coil wire 105 is formed.
[0004]
An object of the present invention is to provide a multipole magnetizing yoke capable of sufficiently and evenly magnetizing a high performance rare earth magnet.
[0005]
[Means for Solving the Problems]
The multipolar magnetizing yoke of the present invention includes a yoke body having a yoke surface facing the magnetized surface of the magnetized body, and a plurality of coil wire mounting grooves formed in parallel on the yoke surface. An exciting coil wire is mounted along the plurality of mounting grooves, and a current to magnetize the magnetized surface is generated by energizing the exciting coil wire. Here, the yoke body is made of an iron-based alloy containing Co in the range of 25 to 60% by weight. If the Co content is outside the above range, the saturation magnetic flux density or permeability of the material will decrease, leading to a shortage of the magnetizing magnetic field. The Co content is desirably 45 to 55% by weight. In the iron-based alloy, the balance other than Co is substantially composed of Fe, but other alloy elements can be added within a range that does not extremely reduce the permeability and saturation magnetic flux density of the alloy. For example, from the viewpoint of improving the toughness of the material, V can be added within a range of 1 to 3% by weight.
[0006]
Here, it is assumed that the mounting groove is opened to both ends of the yoke body in the longitudinal direction, and the exciting coil wire is folded over at both ends of the yoke body and mounted across all the mounting grooves. it can.
[0007]
The mounting groove includes a first groove portion at a first depth position in the groove depth direction and a second groove portion at a second depth position in the transverse section thereof, and the first and second grooves. These groove portions can be connected to each other by a connecting groove portion narrower than the groove width of each of the groove portions. In this case, each mounting groove can be opened to both end faces of the yoke body in the longitudinal direction. The exciting coil wire is alternately folded back at both end faces of the yoke body, and the two wire portions are alternately mounted in the first or second groove portion sequentially with respect to the adjacent mounting grooves. Can be provided. The second wire portion is alternately folded so that the end surface on which the folded portion is generated is opposite to the first wire portion, and a groove portion to which the wire is attached is provided for each attachment groove. The first or second groove portion is mounted so as to be opposite to the first wire portion.
[0008]
In the configuration in which the mounting groove includes the first and second groove portions described above, the yoke body can be made of a general iron-based soft magnetic material such as electromagnetic soft iron or Fe—Ni-based alloy.
[0009]
In the multipolar magnetizing yoke of the present invention, a back yoke portion can be provided on the opposite side of the yoke body with the magnetized body interposed therebetween.
[0010]
In the multipolar magnetizing yoke of the present invention, the yoke surface can be specifically formed into a shape corresponding to the outer peripheral surface or inner peripheral surface of the magnetized body formed in a ring shape or a cylindrical shape.
[0011]
[Action and effect of the invention]
In the multipolar magnetizing yoke of the present invention, an exciting coil wire is installed in a mounting groove formed in parallel along a yoke surface facing the magnetized surface of the magnetized body, and the exciting coil wire is attached to the exciting coil wire. The magnetized surface is multipolar magnetized by energization, and the yoke body is made of an iron-based alloy containing Co in a range of 25 to 65% by weight. By using an alloy having the above composition, the saturation magnetic flux density of the yoke material is improved as compared with a conventional yoke made of electromagnetic soft iron or the like, so that a larger magnetizing magnetic field can be generated, and as a result High performance rare earth magnets can be magnetized sufficiently and uniformly. In addition, since the magnetic permeability is superior to that of electromagnetic soft iron or the like, a sufficiently strong magnetized magnetic field can be obtained without enlarging the energization amount of the coil wire. In particular, in a magnetizing yoke configured to be mounted across all of the mounting groove while opening the mounting groove at both ends of the yoke body and folding the exciting coil wire, the coil wire The difference in the magnetization magnetic field strength between the side where the folded portion is formed and the side where the folded portion is not formed becomes small, and the surface magnetic flux density is less likely to be biased or uneven in the magnet after magnetization.
[0012]
In the configuration in which the first and second groove portions are provided in the mounting groove for the coil wire, the number of turns of the excitation coil wire to be mounted can be increased. Can be sufficiently and uniformly magnetized. Then, two wire portions that are alternately mounted in the first or second groove portion sequentially for each of the adjacent mounting grooves while the coil wire for excitation is alternately folded at both end faces of the yoke body. The second wire portion is alternately folded so that the end surface on the side where the folded portion is generated is opposite to the first wire portion, and for each mounting groove, Since the groove portion to which the wire is attached is attached to the first or second groove portion so that the first wire portion is opposite to the first wire portion, both coil portions for excitation have folded portions at both ends of the yoke. It is attached to the yoke body while supplementing each other, and the non-uniformity of the magnetizing magnetic field based on the presence or absence of the folded portion is eliminated, so that the magnetizing can be performed more efficiently.
[0013]
In the configuration in which the back yoke portion is provided on the opposite side of the yoke body with the magnetized body interposed therebetween, the magnetizing magnetic field can be made uniform in the magnet thickness direction.
[0014]
【Example】
Hereinafter, some embodiments of the present invention will be described with reference to the drawings.
(Example 1)
FIG. 1 shows an example of a multi-pole magnetizing yoke according to the present invention. A multipolar magnetizing yoke (hereinafter also simply referred to as a yoke) 1 is for magnetizing a ring-shaped permanent magnet member in the radial direction, and is, for example, Fe-49 wt% Co-2 wt% A yoke body 10 made of a V alloy (so-called permendur alloy) is provided, and a plurality of mounting grooves 4 are formed in parallel on the inner peripheral surface of the hole 2 along the axial direction. As shown in FIG. 2, each mounting groove 4 has a groove portion 4 a having a substantially circular cross section, and an opening portion 4 b that is integrally formed with the groove portion 4 a and opens to the inner peripheral surface side of the hole portion 2. The part 4b is formed narrower than the groove part 4a, and has a keyhole-like cross-sectional shape as a whole. The yoke body 10 having such a shape can be manufactured, for example, by forming a cylindrical preliminary body by precision casting or the like, and forming the mounting groove 4 on the inner peripheral surface thereof by electric discharge machining or laser machining.
[0015]
As shown in FIGS. 3 and 4, an excitation coil wire 5 is mounted in each mounting groove 4. The mounting groove 4 is open to both ends of the yoke body 10 in the longitudinal direction, and the coil wire 5 is folded back on the end side of the yoke 1, and turns one by one over all the mounting grooves 4. It is installed.
[0016]
As shown in FIG. 1, a ring magnet 3 obtained by molding, for example, Nd—Fe—B rare earth magnet powder together with a resin as a magnetized body in a hole 2 of a yoke 1 is arranged concentrically, When the coil wire 5 is energized using a magnetic power source, the outer peripheral surface (magnetized surface) of the ring magnet 3 extends in the radial direction (thickness direction) from the inner peripheral surface (yoke surface) 1a of the yoke 1 as shown in FIG. ) Is generated, and the ring magnet 3 is magnetized in the radial direction. Here, the direction of the current flowing through the coil wire 5 mounted in each mounting groove 4 is alternately reversed, and the direction of the magnetic field penetrating each region 1b of the yoke surface 1a defined by the open portion 4b is also alternately. It will be reversed. Thereby, the magnetized surface 3a of the ring magnet 3 is divided in the circumferential direction corresponding to each of the above-described regions 1b of the yoke surface 1a, that is, in correspondence with the number of the mounting grooves 4 formed. The magnetic poles are formed so as to be alternately reversed, and a so-called multipolar radial magnetization state is obtained.
[0017]
FIG. 6 shows magnetization curves of electromagnetic soft iron (B) used in a conventional yoke and permendur (A) used in the yoke of the present invention. Permendur saturation magnetization ISA is larger than the saturation magnetization ISB of electromagnetic soft iron, and the permeability of permendur is larger than that of permendur. Uniform and large magnetized. As a result, a magnetic field sufficient to uniformly and sufficiently magnetize a high performance magnet such as a rare earth magnet can be generated.
[0018]
7 (a) and 7 (b), yokes having the shape shown in FIG. 1 are made of permendur and electromagnetic soft iron, respectively, and ring-shaped Nd—Fe—B based bonded magnets (height 15 mm, An example of measurement of the surface magnetic flux density distribution on the outer peripheral surface (magnetized surface) of the magnet in the case of radial magnetization of 48 poles with an inner diameter of 18 mm and an outer diameter of 20 mm is shown. Here, the current value applied to the coil wire 5 for magnetization was 12 kA for electromagnetic soft iron and 10 kA for permendur. When an electromagnetic soft iron product is used, the average value of the magnetic flux density at the peak portion of the distribution curve is about 1200 G. On the other hand, when a permendur product is used, the amount of current supplied to the coil wire 5 is slightly increased. Although it is small, it can be seen that the average value of the magnetic flux density in the peak portion is improved to 2300 G, which is nearly double.
[0019]
FIG. 8 schematically shows the surface magnetic flux density distribution on the outer peripheral surface of the ring magnet. (A) is a yoke made of electromagnetic soft iron, and (b) is made of the permendur of the present invention. Each case is shown. That is, when an electromagnetic soft iron yoke is used, the surface magnetic flux density is high on the side corresponding to the folded portion 5a of the coil wire, and is low on the side where it is not formed. On the other hand, when a permendur yoke is used, such uneven magnetization is less likely to occur, and the whole can be magnetized uniformly.
[0020]
Hereinafter, some modified examples of the magnetizing yoke will be described. In the yoke 11 shown in FIG. 9, the mounting groove 4 is formed in parallel in the axial direction with the outer peripheral surface of the columnar or cylindrical yoke body 10 as the yoke surface 11a. In this case, the ring-shaped magnet 3 is concentrically disposed outside the yoke 11 and a magnetizing magnetic field is applied from the inner peripheral surface side thereof. Further, in the yoke 21 shown in FIG. 10, the yoke surface 21a is formed flat, and the mounting grooves 4 are formed substantially parallel to each other at equal intervals. By using such a yoke 21, the plate-like magnet member 23 can be multipolarly magnetized in the thickness direction. Further, as shown in FIG. 11, the yoke surface 21a is formed in a convex shape or a concave shape so as to constitute a part of the cylindrical surface, and the mounting groove 4 is formed in parallel along the axial direction thereof, whereby the yoke surface 21a is formed. An arcuate magnet member 23 having a peripheral surface corresponding to the surface 21a can be multipolarly magnetized in the radial direction (thickness direction).
[0021]
In the magnetizing yoke of the present invention, a back yoke portion can be provided on the opposite side of the yoke body with the magnetized body interposed therebetween. For example, in the case of the yoke 1 having the shape shown in FIG. 1, as shown in FIG. 12, a ring-shaped back yoke portion 8 can be provided inside the ring magnet 3 arranged on the inside thereof. The back yoke portion 8 may be made of the same material as that of the yoke body 10, but may be made of a different material, for example, one made of electromagnetic soft iron or the like can be used. By providing the back yoke portion 8, as shown in FIG. 12, the magnetizing magnetic field is less likely to diverge on the inner peripheral surface side of the ring magnet 3, and magnetizing unevenness in the radial direction (thickness direction) of the magnet is prevented. be able to. Further, as shown in FIG. 13, such a back yoke portion 8 can also be provided for a magnetizing yoke 21 having a flat yoke surface as shown in FIG.
[0022]
The yokes 1, 11 and 21 can be made of an Fe-30 wt% Co alloy instead of the alloy having the above composition. Thereby, the magnetic flux density of a yoke can be improved 20-30% rather than that of electromagnetic soft iron.
(Example 2)
FIG. 14 shows an example of the configuration of a multipole magnetizing yoke 41 having two mounting grooves. The yoke 41 is made of a permendur alloy as in the first embodiment, and includes a cylindrical yoke body 10 having an appearance similar to that of the yoke 1 shown in FIG. 1, but as shown in FIG. In the cross section of the groove 4, the first groove portion 4a is formed on the inner peripheral surface side (first depth position) of the yoke 1, and the second groove portion 4b is formed on the outer peripheral surface side (second depth position). The first and second groove portions 4a and 4b are connected to each other by a connecting groove portion 4c that is narrower than the groove width of each groove portion. As shown in FIG. 16, the mounting groove 4 is open to both end portions of the yoke body 10 in the longitudinal direction, and the first and second groove portions 4a and 4b (FIG. 14) are respectively provided for excitation. The first wire portion 15 and the second wire portion 25 of the coil wire are mounted over the entire mounting groove 4 while being folded at both ends of the yoke body 10.
[0023]
Here, as shown in FIG. 15, the first wire portion 15 is folded back alternately at both end faces of the yoke body 10, and the first or second groove portion is arranged for each of the mounting grooves 4 arranged adjacent to each other. 4a and 4b are mounted alternately in turn. In addition, the second wire portion 25 is alternately folded so that the end surface on which the folded portion 25 a is generated is opposite to the first wire portion 15, and the wire is attached to each attachment groove. The first groove portion 4a or the second groove portion 4b is sequentially mounted so that the groove portions to be formed are opposite to the first wire portion 15. The first and second wire portions 15 and 25 can be connected to each other on one end side, and the other end side can be connected to a magnetized power source (not shown). In this way, as shown in FIG. 16, at both ends of the yoke 41, the first and second wire portions 15 and 25 are attached to the yoke body 10 while complementing the folded portions 15a and 25a. By energizing from the magnetizing power source, as shown in FIG. 17, it is possible to eliminate the uneven magnetization due to the presence or absence of the folded portion. Such an effect can be similarly achieved even when the yoke 41 is composed of another iron-based soft magnetic material such as electromagnetic soft iron instead of permendur. Moreover, the yoke main body 10 can also be formed by laminating silicon steel plates having a predetermined shape in the thickness direction. In addition, it is good also as a structure which forms the 1st and 2nd wire part parts 15 and 25 as a separate wire, and each connects to a magnetized power supply so that the energization direction may become the same as the said structure.
[0024]
As shown in FIG. 18, the folding direction of the coil wire 15 attached to the first groove 4a and the folding direction of the coil wire 25 attached to the second groove 4b are in the same direction. The wires 15 and 25 can be attached to the yoke 41.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external appearance of a multipole magnetizing yoke according to Embodiment 1 of the present invention.
FIG. 2 is a partial plan view of FIG.
3 is an enlarged perspective view showing a yoke surface side of the multi-pole magnetizing yoke shown in FIG. 1;
FIG. 4 is a diagram schematically illustrating a method of attaching a coil wire to a yoke according to the first embodiment.
FIG. 5 is a schematic diagram showing a generation state of a magnetizing magnetic field in the multipolar magnetized yoke of FIG. 1;
FIG. 6 is a magnetization curve of electromagnetic soft iron and permendur alloy.
FIG. 7 is a graph showing a measurement example of surface magnetic flux density distribution of a magnet member magnetized by using a conventional magnetizing yoke and a magnetizing yoke of Example 1 in a multipolar manner.
FIG. 8 is a diagram schematically showing a surface magnetic flux density distribution state of a magnet member magnetized with multiple poles using a conventional magnetizing yoke and a magnetizing yoke of Example 1;
FIG. 9 is a perspective view showing a first modification of the magnetizing yoke according to the first embodiment.
FIG. 10 is a perspective view showing a second modified example.
FIG. 11 is a perspective view showing a third modified example.
FIG. 12 is a plan view showing an example of a magnetizing yoke having a back yoke portion.
FIG. 13 is a plan view showing a modified example of the same.
14 is a perspective view partially showing a magnetizing yoke of Example 2. FIG.
FIG. 15 is a plan view thereof.
FIG. 16 is a diagram schematically illustrating a method of attaching a coil wire to a yoke according to the second embodiment.
FIG. 17 is a diagram schematically showing a surface magnetic flux density distribution state of a magnet member magnetized with multiple poles using the magnetizing yoke of the second embodiment.
FIG. 18 is a view showing a modification of the method for attaching the coil wire to the yoke of the second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11, 21, 31, 41 Multipolar magnetizing yoke 1a Yoke surface 3, 23 Magnet member 3a Magnetizing surface 4 Mounting groove 4a First groove 4b Second groove 4c Connection groove 5 Excitation coil wire 10 Yoke Main body 15 First wire part 25 Second wire part 5a, 15a, 25a Turned part

Claims (4)

A yoke main body having a yoke surface that is made of an iron-based alloy containing Co in a range of 25 to 60% by weight and is opposed to the magnetized surface of the magnetized body;
A plurality of coil wire mounting grooves formed in parallel on the yoke surface, the first groove portion at the first depth position in the groove depth direction and the second depth in the transverse section thereof The first and second groove portions are connected to each other by connecting groove portions that are narrower than the groove widths of the respective groove portions, and open to both end surfaces of the yoke body in the longitudinal direction. A mounting groove that is supposed to be
With exciting coil wire along which RaSo in groove is adapted to be mounted, the exciting coil wire, while folded alternately in both end surfaces of the yoke main body, it arranged adjacent each mounting The first wire rods, which are alternately mounted in the first or second groove portion sequentially with respect to the grooves, and the end surfaces on the side where the folded portion is formed on both end surfaces of the yoke body are the first wire rods. The first or the first or the second wire portion so that the groove portion in which the wire is mounted is alternately folded back so as to be opposite to each other, and the first wire rod portion is opposite to the first wire portion. It is supposed to include second wire rod portions that are alternately mounted in the second groove portion,
A multi-pole magnetizing yoke, wherein a magnetic field for magnetizing the magnetized surface is generated by energizing the exciting coil wire. A yoke body made of an iron-based soft magnetic material and having a yoke surface facing the magnetized surface of the magnetized body;
  A plurality of coil wire mounting grooves formed in parallel on the yoke surface, the first groove portion at the first depth position in the groove depth direction and the second depth in the transverse section thereof The first and second groove portions are connected to each other by connecting groove portions that are narrower than the groove widths of the respective groove portions, and open to both end surfaces of the yoke body in the longitudinal direction. A mounting groove that is supposed to be
  Excitation coil wires are mounted along the mounting grooves, and the excitation coil wires are alternately folded at both end faces of the yoke body, and are adjacent to the mounting grooves arranged adjacent to each other. On the other hand, the first wire rod portions that are alternately mounted in the first or second groove portion, and the end surfaces on the side where the folded portion is formed on both end surfaces of the yoke body are the first wire rod portions. Are alternately folded so as to be opposite to each other, and for each of the mounting grooves, the first or second portion is arranged such that the groove portion to which the wire is attached is opposite to the first wire portion. And the second wire rod portions that are alternately mounted in the groove portions of
  A multi-pole magnetizing yoke, wherein a magnetic field for magnetizing the magnetized surface is generated by energizing the exciting coil wire. 3. The multipolar magnetizing yoke according to claim 1, further comprising a back yoke portion provided on a side opposite to the yoke main body with the magnetized body interposed therebetween. The multi-pole magnetization according to any one of claims 1 to 3, wherein the yoke surface is formed in a shape corresponding to an outer peripheral surface or an inner peripheral surface of a magnetized body formed in a ring shape or a cylindrical shape. For yoke.

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