Magnetic field orientation device and magnetic field orientation unit

Abstract

To provide a magnetic field orientation device for applying a magnetic field to a sheet-like (band-like) workpiece, and a magnetic field orientation unit including the same.SOLUTION: A magnetic field orientation device 32 includes a pair of magnet portions 16 arranged in a first direction D1 so that opposite poles are opposed to each other, and a yoke 34 for holding the pair of magnet portions 16. The yoke 34 has a pair of first yoke portions 34a to which the magnet portions 16 are fixed, and a second yoke portion 34b connecting the pair of first yoke portions 34a. When viewed from the first direction D1, the outer edges of the magnet portions 16 are positioned more inwardly than the outer edges of the first yoke portions 34a. Each magnet portion 16 includes a plurality of magnet rows 161 to 164, and each of the magnet rows 161 to 164 includes a plurality of magnets 16a. The plurality of magnets 16a of one of the plurality of magnet rows 161 to 164 and the plurality of magnets 16a of the other magnet row adjacent to the one magnet row are arranged so as to be offset from each other.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a magnetic field orientation device that applies a magnetic field to a sheet-shaped (strip-shaped) workpiece and a magnetic field orientation unit including the same.

Background Art

[0002] As methods for applying a magnetic field to a sheet-shaped workpiece, a method using a coil and a method using a magnet are known.

[0003] When applying a magnetic field to a workpiece using a coil, the magnetic field strength can be adjusted by adjusting the voltage applied to the coil. Therefore, a high-intensity magnetic field can be easily applied to the workpiece. However, when using a coil, a power supply device for applying a voltage to the coil and a cooling device as a heat dissipation measure are required, so the device configuration becomes large-scale.

[0004] On the other hand, when applying a magnetic field to a workpiece using a magnet, for example, as in the magnetic field orientation device disclosed in Patent Document 1, magnets are arranged on both sides of a workpiece (in Patent Document 1, a strip-shaped non-magnetic support coated with a magnetic paint) so that different poles face each other, and it is conceivable to apply a magnetic field to the workpiece while transporting the workpiece. When applying a magnetic field to a workpiece using a magnet in this way, a power supply device and a cooling device are not required, so the device configuration can be simplified. However, since the magnetic field strength cannot be adjusted as in the case of using a coil, a powerful magnet is required when applying a high-intensity magnetic field to the workpiece.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In order to appropriately apply a magnetic field to the workpiece while transporting the workpiece, it is necessary to generate a magnetic field within a sufficient range in the transport direction of the workpiece. For this purpose, for example, it is conceivable to use a magnet with large dimensions. However, it is difficult to form a powerful magnet with large dimensions. Therefore, for example, it is conceivable to arrange a plurality of magnets so as to be aligned in the transport direction of the workpiece.

[0007] However, as a result of investigations by the present inventor, it has been found that when attempting to arrange powerful magnets so as to be aligned in the transport direction of the workpiece, a large repulsive force is generated between adjacent magnets, making it impossible to easily install the magnets.

[0008] Therefore, an object of the present invention is to provide a magnetic field orientation device that is easy to install and a magnetic field orientation unit including the same.

Means for Solving the Problems

[0009] The magnetic field orientation device according to one aspect of the present invention includes: a pair of magnet parts arranged so that unlike poles face each other and are spaced apart from each other in a first direction; a yoke that holds the pair of magnet parts; the yoke includes: a pair of first yoke parts provided outside the pair of magnet parts in the first direction and to which the magnet parts are respectively fixed; a second yoke part provided outside the pair of magnet parts in a second direction orthogonal to the first direction and connecting the pair of first yoke parts; when viewed from the first direction, the outer edge of the magnet part is positioned inside the outer edge of the first yoke part; the magnet part includes a plurality of magnet rows provided so as to be aligned in a third direction orthogonal to the first direction and the second direction; each of the magnet rows includes a plurality of magnets provided so as to be aligned in the second direction; Among the plurality of magnet arrays, the plurality of magnets in one magnet array and the plurality of magnets in another magnet array adjacent to the one magnet array are arranged so as to be displaced from each other in the second direction.

[0010] The magnetic field orientation unit in another aspect of the present invention includes a plurality of the magnetic field orientation devices each having a pair of magnet portions arranged such that opposite poles face each other and are spaced apart from each other in a first direction, and a yoke that holds the pair of magnet portions. The yoke is provided outside the pair of magnet portions in the first direction, and includes a pair of first yoke portions to which the magnet portions are respectively fixed, and a second yoke portion provided outside the pair of magnet portions in a second direction orthogonal to the first direction and connecting the pair of first yoke portions. When viewed from the first direction, the outer edge of the magnet portion is positioned inside the outer edge of the first yoke portion. The plurality of magnetic field orientation devices are arranged side by side in a third direction orthogonal to the first direction and the second direction. The magnet portions of each of the magnetic field orientation devices include a plurality of magnets provided side by side in the second direction. Among the plurality of magnetic field orientation devices, the plurality of magnets in one magnetic field orientation device and the plurality of magnets in another magnetic field orientation device adjacent to the one magnetic field orientation device are arranged so as to be displaced from each other in the second direction.

Advantages of the Invention

[0011] According to the present invention, a magnetic field orientation device that is easy to install and a magnetic field orientation unit including the same can be obtained.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Figure 8

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Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0013] (Examination by the present inventor) The present inventor has studied a method of applying a magnetic field to a workpiece using a magnet. FIG. 1 is a diagram for explaining the study content by the present inventor. Specifically, FIG. 1 shows equipment for applying a magnetic field to a sheet-shaped workpiece W. The equipment 1 shown in FIG. 1 includes a transport device 100 for transporting the workpiece W and a plurality of magnet units 200 for applying a magnetic field to the workpiece W.

[0014] The transport device 100 includes a plurality of rollers 102 and a transport belt 104 supported by the plurality of rollers 102. The transport belt 104 is driven by a drive source (not shown) to transport the workpiece W on the transport belt 104 in the direction indicated by arrow A (hereinafter referred to as the transport direction A).

[0015] The plurality of magnet units 200 are arranged side by side in the conveying direction A. Each magnet unit 200 has a pair of magnets 202 and 204. Magnet 202 is provided on one side of the conveyor belt 104, and magnet 204 is provided on the other side of the conveyor belt 104. In each magnet unit 200, magnets 202 and 204 are arranged such that opposite poles face each other. Thereby, a magnetic field in one direction (for example, the direction from magnet 204 to magnet 202) is generated between magnet 202 and magnet 204.

[0016] In the facility 1 shown in FIG. 1, while the work W is being conveyed by the conveying device 100, a magnetic field in one direction can be applied to the work W using the plurality of magnet units 200. However, as a result of investigations by the present inventor, when strong magnets (for example, magnets that generate a magnetic flux of about 1 T) are used as magnets 202 and 204, a large repulsive force is generated between adjacent magnets in the conveying direction A, and it was found that each magnet unit 200 cannot be easily installed.

[0017] Therefore, the present inventor tried to control the flow of the magnetic flux generated by magnets 202 and 204 by providing a yoke so as to connect magnets 202 and 204. However, simply providing a yoke so as to connect magnets 202 and 204 was not sufficient to sufficiently reduce the repulsive force generated between adjacent magnets in the conveying direction A.

[0018] The present inventor further conducted investigations and considered providing a yoke so as to sandwich magnets 202 and 204 from above and below. As a result, it was found that by appropriately adjusting the positional relationship between the magnet and the yoke, the repulsive force generated between adjacent magnets in the conveying direction A can be sufficiently reduced. Specifically, it was found that by holding the pair of magnets with a yoke so as to sandwich them from above and below such that the pair of magnets do not protrude from the yoke in the conveying direction A, the repulsive force generated between adjacent magnets in the conveying direction A can be sufficiently reduced.

[0019] Based on the above findings, the inventor of the present invention fabricated a magnetic field orientation device according to Reference Example 1 described below and a magnetic field orientation unit equipped with the same.

[0020] (Reference Example 1) FIG. 2 is a schematic view showing a facility equipped with the magnetic field orientation device according to Reference Example 1. The facility 10 shown in FIG. 2 is different from the facility 1 shown in FIG. 1 in that it is equipped with a magnetic field orientation unit 12 instead of a plurality of magnet units 200.

[0021] FIG. 3 is a perspective view showing the magnetic field orientation unit. As shown in FIGS. 2 and 3, the magnetic field orientation unit 12 includes a plurality of magnetic field orientation devices 14 arranged in line with the conveyance direction A of the workpiece W. In FIG. 3, a first direction D1, a second direction D2, and a third direction D3 that are orthogonal to each other are shown. The third direction D3 is a direction parallel to the conveyance direction A. In other drawings as well, the first direction D1, the second direction D2, and the third direction D3 are appropriately shown.

[0022] A cavity for passing the conveyance belt 104 and the workpiece W (see FIG. 2) supported by the conveyance belt 104 is formed at the central portion of each magnetic field orientation device 14. Hereinafter, the magnetic field orientation device 14 will be specifically described.

[0023] FIG. 4 is a view showing the magnetic field orientation device 14, where (a) is a view of the magnetic field orientation device 14 seen from the third direction D3, and (b) is a view of the magnetic field orientation device 14 seen from the first direction D1. As shown in FIGS. 3 and 4(a), the magnetic field orientation device 14 includes a pair of magnet portions 16 and a yoke 18 that holds the pair of magnet portions 16.

[0024] The pair of magnet parts 16 are magnetized in the first direction D1. The pair of magnet parts 16 are arranged such that opposite poles face each other and are spaced apart from each other in the first direction D1. Thereby, a unidirectional magnetic field (hereinafter referred to as a unidirectional magnetic field) is generated between the pair of magnet parts 16 from one magnet part 16 toward the other magnet part 16. In this Reference Example 1, when the work W (see FIG. 2) passes through the gap between the pair of magnet parts 16, a magnetic field is applied to the work W. Note that the distance between the pair of magnet parts 16 in the first direction D1 is appropriately adjusted according to the type, use, etc. of the work W. In this Reference Example 1, the distance between the pair of magnet parts 16 is set to, for example, 10 mm.

[0025] In this Reference Example 1, the magnet part 16 is formed in a rectangular parallelepiped shape so as to extend in the second direction D2. As shown in FIG. 4(a), in this Reference Example 1, the magnet part 16 is composed of a plurality of rectangular parallelepiped magnets 16a provided so as to be arranged in the second direction D2. As the magnet 16a, a known permanent magnet can be used. Specifically, as the magnet 16a, for example, a rare earth magnet such as a neodymium magnet and a samarium cobalt magnet, or a ferrite magnet or an alnico magnet can be used. In this Reference Example 1, the magnets 16a adjacent to each other in the second direction D2 are fixed to each other by, for example, an adhesive.

[0026] In this Reference Example 1, the yoke 18 is provided so as to surround the pair of magnet parts 16. A cavity 19 penetrating in the third direction D3 is formed in the central portion of the yoke 18. In this Reference Example 1, the yoke 18 has a rectangular tube shape. The length of the yoke 18 in the second direction D2 is longer than the length in the first direction D1. The yoke 18 is composed of a magnetic material such as a steel material. Specifically, as the material of the yoke 18, SS400, SUS430, SUS403, etc. defined by JIS standards can be used.

[0027] In this Reference Example 1, the yoke 18 includes a pair of first yoke portions 18a and a pair of second yoke portions 18b. In FIG. 4(a), the boundary between the first yoke portion 18a and the second yoke portion 18b is indicated by a dashed line. The pair of first yoke portions 18a are provided outside the pair of magnet portions 16 in the first direction D1. The magnet portions 16 are fixed to the pair of first yoke portions 18a respectively. In this Reference Example 1, for example, the magnet portions 16 are fixed to the first yoke portions 18a by an adhesive.

[0028] In this Reference Example 1, among the yoke 18, the portions on one side and the other side of the pair of magnet portions 16 in the first direction D1 are respectively defined as the first yoke portions 18a. The pair of second yoke portions 18b are provided outside the pair of magnet portions 16 in the second direction D2 and connect the pair of first yoke portions 18a.

[0029] As shown in FIG. 4(b), when viewed from the first direction D1, the outer edge of the magnet portion 16 is positioned inside the outer edge of the first yoke portion 18a. In other words, the first yoke portion 18a protrudes on both sides of the magnet portion 16 in the third direction D3. In this Reference Example 1, in the third direction D3, the length b of the first yoke portion 18a is preferably 1.1 times or more, more preferably 1.6 times or more, the length a of the magnet portion 16. In this Reference Example 1, the length of the second yoke portion 18b in the third direction D3 is set in the same manner as the length b of the first yoke portion 18a. In this Reference Example 1, the length c of the first yoke portion 18a in the first direction D1 is preferably set to be 0.5 to 3.5 times the length b of the first yoke portion 18a in the third direction D3. Also, the length d of the second yoke portion 18b in the second direction D2 is preferably set to be 0.5 to 3.5 times the length of the second yoke portion 18b in the third direction D3.

[0030] (Function and Effect of Reference Example 1) In the magnetic field orientation device 14 according to the first reference example 1, when viewed from the first direction D1, the outer edge of the magnet portion 16 is positioned inside the outer edge of the first yoke portion 18a. Thereby, it is possible to suppress the leakage of magnetic flux radially from the end face (the end face fixed to the first yoke portion 18a) on the side of the first yoke portion 18a of the magnet portion 16. As a result, when a plurality of magnetic field orientation devices 14 are arranged in the transport direction A, it is possible to prevent a large repulsive force from occurring between the magnetic field orientation devices 14 adjacent to each other in the transport direction A. Thereby, it becomes easy to install each magnetic field orientation device 14 in close proximity.

[0031] FIG. 5 is a diagram showing an example of the strength of the magnetic field generated by a plurality of magnet portions 16 in the magnetic field orientation unit 12 shown in FIG. 3. Specifically, the horizontal axis in FIG. 5 indicates the position in the transport direction A, and the vertical axis indicates the magnetic flux density in the first direction D1. Note that the magnetic flux density shown in FIG. 5 indicates the magnetic flux density of the magnetic field at the center of the magnetic field orientation unit 12 in the second direction D2.

[0032] In the magnetic field orientation unit 12 shown in FIG. 3, four magnetic field orientation devices 14 are arranged so as to be aligned in the transport direction A. For this reason, as shown in FIG. 5, the magnetic flux density of the magnetic field generated by the magnetic field orientation unit 12 changes so as to show four peaks. Here, as shown in the portion surrounded by the one-dot chain line in FIG. 5, portions where magnetic flux flows in a direction opposite to the above-described one-way magnetic field are generated on one side and the other side of the magnetic field orientation unit 12 in the transport direction A. That is, a reverse magnetic field is generated on the inlet side and the outlet side of the magnetic field orientation unit 12. In this regard, in the magnetic field orientation device 14 according to the first reference example 1, as described above, it is possible to suppress the leakage of magnetic flux radially from the end face on the side of the first yoke portion 18a of the magnet portion 16. Thereby, the intensity of the reverse magnetic field can be made sufficiently low. As a result, a one-way magnetic field can be appropriately applied to the workpiece W.

[0033] Note that the purpose of applying a magnetic field to the workpiece W is not particularly limited. Also, there are no particular restrictions on the workpiece W. Examples of the workpiece W include a rubber magnet, a magnetic paint, a magnetic fluid, a semiconductor wafer, a polymer slurry containing magnetic particles, a film-shaped electrode, and the like. In the above-mentioned Reference Example 1, the workpiece W is conveyed by the conveyor belt 104. However, when applying a magnetic field to a strip-shaped workpiece, the workpiece may be passed through the magnetic field orientation unit 12 while being supported by the roller 102.

[0034] (Simulation) The inventor investigated the influence of the dimensions of the yoke 18 on the magnetic field strength and the like by means of a simulation using electromagnetic field analysis software (JMAG manufactured by JSOL Corporation) for the above-mentioned magnetic field orientation unit 12. Specifically, referring to FIG. 4, the length b of the first yoke portion 18a in the third direction D3, the length c of the first yoke portion 18a in the first direction D1, and the length d of the second yoke portion 18b in the second direction D2 were changed to perform magnetic field analysis. Then, the magnetic flux density of the demagnetizing field (see FIG. 5), the magnetic flux density (peak value) of the unidirectional magnetic field generated in the magnetic field orientation unit 12, and the repulsive force generated between the magnetic field orientation devices 14 adjacent to each other in the third direction D3 (conveying direction A) were obtained. Note that the cross-sectional area of the first yoke portion 18a orthogonal to the second direction D2 and the cross-sectional area of the second yoke portion 18b orthogonal to the first direction D1 were constant (5600 mm 2 ). Also, the dimensions of the magnet portion 16 and the dimensions of the cavity portion 19 were made constant. Specifically, the magnet portion 16 was configured such that 11 magnets 16a (neodymium magnets) were arranged in the second direction D2. The length of the magnet portion 16 in the first direction D1 was 24 mm, the length in the second direction D2 was 396 mm, and the length a in the third direction D3 was 36 mm. The length of the cavity portion 19 in the first direction D1 was 58 mm, and the length in the second direction D2 was 420 mm. The material of the yoke 18 was SS400.

[0035] Table 1 below shows the dimensions of the analysis model and the analysis results. In Table 1 below, a to d of the magnet and the yoke indicate the lengths a to d in Fig. 4, and b / a of the yoke indicates the value of the ratio of the lengths b and a. The mass indicates the mass of the magnetic field orientation device 14 calculated from the dimensions of each part (the total mass of the pair of magnet parts 16 and the yoke 18). The reverse magnetic field ratio represents the value of the ratio of the magnitude of the magnetic flux density of the reverse magnetic field (absolute value) and the magnitude of the magnetic flux density of the unidirectional magnetic field (absolute value) expressed as a percentage. Note that the analysis model of Analysis No. 1 does not include the yoke 18. The analysis model of Analysis No. 1 has a configuration in which a plurality of magnet parts 16 are arranged in the third direction D3 (transport direction A), similar to the magnets 202 and 204 of the plurality of magnet units 200 shown in Fig. 1. Further, in the analysis models of Analysis No. 2 and 3, the magnet parts 16 protrude from both sides of the first yoke part 18a in the third direction D3. In these analysis models of Analysis No. 1 to 3, the magnet parts 16 adjacent to each other in the third direction D3 (transport direction A) are in contact with each other. On the other hand, the analysis models of Analysis No. 4 to 10 correspond to the above-mentioned Reference Example 1. In the analysis models of Analysis No. 4 to 10, the yokes 18 adjacent to each other in the third direction D3 (transport direction A) are in contact with each other. Note that for Analysis No. 1, the mass indicates the total mass of the pair of magnet parts 16, and the repulsive force indicates the repulsive force generated between the magnet parts 16 adjacent to each other in the third direction D3 (transport direction A).

[0036]

Table 1

[0037] Fig. 6 graphically shows the above analysis results. Specifically, Fig. 6 is a graph showing the relationship between the value of the ratio of the length b of the first yoke part 18a and the length a of the magnet part 16, and the repulsive force generated between the magnetic field orientation devices 14 adjacent to each other in the third direction D3 (for Analysis No. 1, between the magnet parts 16). Further, Fig. 7 shows the relationship between the value of the ratio of the lengths b and a and the mass of the magnetic field orientation device 14.

[0038] As shown in Table 1 and FIG. 6, in Analysis Nos. 4 to 10 corresponding to the above-described Reference Example 1, it was possible to reduce the repulsive force generated between the magnet portions 16 adjacent to each other in the conveyance direction A. That is, it was found that by positioning the outer edge of the magnet portion 16 inside the outer edge of the first yoke portion 18a when viewed from the first direction D1, the repulsive force generated between the magnet portions 16 adjacent to each other in the conveyance direction A can be reduced. Further, from the viewpoint of reducing the above-described repulsive force, it was found that the value of the ratio of the length b to the length a is preferably 1.1 or more, and more preferably 1.6 or more. Furthermore, as shown in Table 1 and FIG. 7, from the viewpoint of reducing the mass of the magnetic field orientation device 14 as well, it was found that the value of the ratio of the length b to the length a is preferably 1.1 or more, and more preferably 1.6 or more.

[0039] Also, as shown in Table 1, in Analysis Nos. 4 to 10 corresponding to the above-described Reference Example 1, it was possible to sufficiently increase the magnetic flux density of the unidirectional magnetic field while sufficiently reducing the magnetic flux density of the reverse magnetic field. That is, it was found that by positioning the outer edge of the magnet portion 16 inside the outer edge of the first yoke portion 18a when viewed from the first direction D1, it is possible to sufficiently increase the magnetic flux density of the unidirectional magnetic field while sufficiently reducing the magnetic flux density of the reverse magnetic field.

[0040] As described above, when the magnetic field orientation unit 12 is configured by the magnetic field orientation device 14 according to Reference Example 1, it was confirmed that a unidirectional magnetic field can be appropriately applied to the workpiece W while easily installing a plurality of magnetic field orientation devices 14 in proximity to each other. On the other hand, the inventor considered weight reduction of the magnetic field orientation device in order to further facilitate the installation of the magnetic field orientation device. Specifically, it was considered to reduce the weight of the magnetic field orientation device (yoke) by miniaturizing the yoke.

[0041] However, simply reducing the size of the yoke may result in a decrease in the amount of magnetic flux passing through the yoke, making it possible that the magnetic flux density of the unidirectional magnetic field cannot be sufficiently ensured. Therefore, the inventor of the present invention has conducted a detailed study on a configuration for reducing the weight of the yoke while suppressing the decrease in the magnetic flux density of the unidirectional magnetic field. During the progress of this study, the inventor examined the magnetic flux density distribution generated in the yoke 18 by the pair of magnet portions 16 through magnetic field analysis using the above-described electromagnetic analysis software. As a result, it was found that almost no magnetic flux flows in the central portion of the yoke 18 in the second direction D2 and both end sides in the first direction D1 (a pair of regions 181 indicated by broken lines in FIG. 4(a)), and the four corners (four regions 182 indicated by broken lines in FIG. 4(a)). From this result, the inventor considered that by removing the above-described portions where almost no magnetic flux flows from the yoke, it is possible to suppress the decrease in the magnetic flux density of the unidirectional magnetic field and reduce the weight of the yoke.

[0042] The present invention has been completed based on the above findings. Hereinafter, the magnetic field orientation device according to Reference Example 2 and the magnetic field orientation unit including the same will be described.

[0043] (Configuration of the Magnetic Field Orientation Device and the Magnetic Field Orientation Unit According to Reference Example 2) FIG. 8 is a perspective view showing a magnetic field orientation unit including the magnetic field orientation device according to Reference Example 2. As shown in FIG. 8, the magnetic field orientation unit 30 according to the present Reference Example 2 is configured to be able to apply a magnetic field to a workpiece W (see FIG. 2) conveyed by a conveyor belt 104, similarly to the magnetic field orientation unit 12 described with reference to FIG. 2.

[0044] Specifically, the magnetic field orientation unit 30 includes a plurality of magnetic field orientation devices 32 arranged so as to be aligned in the conveyance direction A of the workpiece W. Note that FIG. 8 shows a first direction D1, a second direction D2, and a third direction D3 that are orthogonal to each other. The third direction D3 is a direction parallel to the conveyance direction A. In other drawings, the first direction D1, the second direction D2, and the third direction D3 are also appropriately shown.

[0045] In the central part of each magnetic field orientation device 32, a cavity 35 is formed for passing the conveyor belt 104 and the workpiece W (see FIG. 2) supported by the conveyor belt 104. In the present Reference Example 2, the conveyor belt 104 and the workpiece W pass between a pair of magnet parts 16 arranged in the cavity 35. Hereinafter, the magnetic field orientation device 32 will be specifically described. Among the components of the magnetic field orientation device 32, components having substantially the same functions as those of the magnetic field orientation device 14 according to the above-described Reference Example 1 are denoted by the same reference numerals and the description thereof is omitted.

[0046] FIG. 9 is a view of the magnetic field orientation device 32 as seen from the third direction D3. As shown in FIGS. 8 and 9, the magnetic field orientation device 32 includes a pair of magnet parts 16 and a yoke 34 that holds the pair of magnet parts 16. The yoke 34 is provided so as to surround the pair of magnet parts 16. In the central part of the yoke 34, a cavity 35 penetrating in the third direction D3 is formed. The length of the yoke 34 in the second direction D2 is longer than the length in the first direction D1. The yoke 34 is made of the same material as the above-described yoke 18.

[0047] The yoke 34 includes a pair of first yoke parts 34a and a pair of second yoke parts 34b. In the present Reference Example 2, the pair of first yoke parts 34a and the pair of second yoke parts 34b are each constituted by separate members. Note that, like the yoke 34 shown in FIG. 10 to be described later, the pair of first yoke parts 34a and the pair of second yoke parts 34b may be integrally formed. That is, in the present Reference Example 2, the yoke 34 is constituted by a plurality of members, but the yoke 34 may be constituted by one member.

[0048] As shown in FIGS. 8 and 9, in this Reference Example 2, a pair of first yoke portions 34a are provided outside a pair of magnet portions 16 in the first direction D1. Magnet portions 16 are fixed to the pair of first yoke portions 34a, respectively. In this Reference Example 2, for example, the magnet portions 16 are fixed to the first yoke portions 34a by an adhesive. A pair of second yoke portions 34b are provided outside the pair of magnet portions 16 in the second direction D2 and connect the pair of first yoke portions 34a. The pair of first yoke portions 34a and the pair of second yoke portions 34b are fixed, for example, by an adhesive.

[0049] At the central portion of each first yoke portion 34a in the second direction D2, a recess 36 that is recessed toward the magnet portion 16 side in the first direction D1 is formed. In this Reference Example 2, the recess 36 is formed such that the length of the first yoke portion 34a in the first direction D1 increases as the distance from the center of the magnet portion 16 in the second direction D2 increases. In this Reference Example 2, the surface 34c (see FIG. 9) of the first yoke portion 34a to which the magnet portion 16 is fixed is provided to be flat and extend in a direction orthogonal to the first direction D1. As a result, in the portion where the recess 36 is formed, the area of the cross section orthogonal to the second direction D2 of the first yoke portion 34a increases as the distance from the center of the magnet portion 16 in the second direction D2 increases.

[0050] Also, in this Reference Example 2, the corner portions 34d (outer corners in the first direction D1) at both ends of each first yoke portion 34a in the second direction D2 have a shape that is notched in a C shape. As a result, the length of both ends of the yoke 34 in the first direction D1 in the second direction D2 becomes smaller toward the outside in the second direction D2.

[0051] Similar to the magnetic field orientation device 14 according to the above-described Reference Example 1, when viewed from the first direction D1, the outer edge of the magnet portion 16 is positioned inside the outer edge of the first yoke portion 34a. In other words, the first yoke portion 34a protrudes beyond both sides of the magnet portion 16 in the third direction D3. Also in this Reference Example 2, similar to the above-described Reference Example 1, in the third direction D3, the length of the first yoke portion 34a (corresponding to the length b in FIG. 4(b)) is preferably 1.1 times or more, and more preferably 1.6 times or more, the length of the magnet portion 16 (corresponding to the length a in FIG. 4(b)). Note that also in this Reference Example 2, the length of the second yoke portion 34b in the third direction D3 is set in the same manner as the length of the first yoke portion 34a.

[0052] (Operational effects of Reference Example 2) Also in the magnetic field orientation device 32 according to this Reference Example 2, similar to the magnetic field orientation device 14 according to the above-described Reference Example 1, when viewed from the first direction D1, the outer edge of the magnet portion 16 is positioned inside the outer edge of the first yoke portion 34a. Thereby, it is possible to suppress the leakage of magnetic flux radially from the end face (the end face fixed to the first yoke portion 34a) on the first yoke portion 34a side of the magnet portion 16. As a result, when a plurality of magnetic field orientation devices 32 are arranged in the transport direction A, it is possible to prevent a large repulsive force from being generated between the magnetic field orientation devices 32 adjacent to each other in the transport direction A. Thereby, it becomes easy to install the magnetic field orientation devices 32 in close proximity to each other. Further, since leakage of magnetic flux can be suppressed as described above, the intensity of the demagnetizing field generated on the inlet side and the outlet side of the magnetic field orientation unit 30 can be made sufficiently low. Thereby, a unidirectional magnetic field can be appropriately applied to the workpiece W.

[0053] In this Reference Example 2, a recess 36 that is recessed toward the magnet portion 16 side in the first direction D1 is formed in the central portion of each first yoke portion 34a in the second direction D2. As described with reference to the yoke 18 shown in FIG. 4, the amount of magnetic flux passing through the central portion of the first yoke portion 18a (see FIG. 4) to which the magnet portion 16 is fixed is smaller than the amount of magnetic flux passing through other portions of the first yoke portion 18a. For this reason, in this Reference Example 2, even if the cross-sectional area of the central portion of the first yoke portion 34a is reduced by forming the recess 36 in the central portion of the first yoke portion 34a, the flow of magnetic flux in the yoke 34 is not inhibited. That is, in this Reference Example 2, the volume of the yoke 34 (the first yoke portion 34a) can be reduced without inhibiting the flow of magnetic flux. As a result, the weight of the magnetic field orientation device 32 can be reduced without degrading the performance of the magnetic field orientation device 32. As a result, the installation of the magnetic field orientation device 32 becomes even easier.

[0054] Note that in this Reference Example 2, the magnetic flux generated by the pair of magnet portions 16 flows in the first yoke portion 34a from the inside to the outside (or from the outside to the inside) in the second direction D2. For this reason, the amount of magnetic flux passing through the first yoke portion 34a (more specifically, the portion outside the magnet portion 16 in the first direction D1) increases as it moves away from the center of the magnet portion 16 in the second direction D2. Therefore, in this Reference Example 2, the recess 36 is formed so that the length of the first yoke portion 34a in the first direction D1 increases as it moves away from the center of the magnet portion 16 in the second direction D2. As a result, the cross-sectional area (the area of the cross-section perpendicular to the second direction D2) of the portion of the first yoke portion 34a outside the magnet portion 16 in the first direction D1 is increased as it moves away from the center of the magnet portion 16 in the second direction D2. As a result, magnetic flux can flow smoothly in the first yoke portion 34a (yoke 34).

[0055] In this Reference Example 2, the corner 34d of each first yoke portion 34a has a shape that is cut out in a C-plane shape such that the length in the first direction D1 at both ends of the yoke 34 in the second direction D2 becomes shorter toward the outside in the second direction D2. As described with respect to the yoke 18 shown in FIG. 4, the amount of magnetic flux passing through the four corners of the yoke 18 is less than the amount of magnetic flux passing through the other portions of the first yoke portion 18a (see FIG. 4). Therefore, in this Reference Example 2, even if the corner 34d of each first yoke portion 34a has a cut-out shape, the flow of magnetic flux in the yoke 34 is not impeded. That is, the volume of the yoke 34 can be reduced without impeding the flow of magnetic flux. As a result, the magnetic field orientation device 32 can be further lightened without degrading the performance of the magnetic field orientation device 32.

[0056] In the yoke 34 shown in FIG. 9, a recess 36 is formed such that the length of the first yoke portion 34a in the first direction D1 continuously increases as it moves away from the center of the magnet portion 16 in the second direction D2. However, the shape of the recess is not limited to the above example. For example, the recess may be formed such that the length of the first yoke portion 34a in the first direction D1 increases stepwise as it moves away from the center of the magnet portion 16 in the second direction D2.

[0057] In the yoke 34 shown in FIG. 9, the corner 34d of the first yoke portion 34a has a shape that is cut out in a C-plane shape. However, the shape of the corner 34d is not limited to the above example. For example, the corner 34d may have a shape that is cut out in an R-plane shape.

[0058] In the magnetic field orientation unit 30 shown in FIG. 8, a plurality of magnetic field orientation devices 32 are provided so as to be in contact with each other in the transport direction A. However, a gap may be provided between the magnetic field orientation devices 32 adjacent to each other in the transport direction A. However, in this case, it is preferable to adjust the distance between the magnetic field orientation devices 32 so as to suppress the generation of a demagnetizing field between the magnetic field orientation devices 32 adjacent to each other in the transport direction A.

[0059] In the above Reference Examples 1 and 2, the case where the magnet portion 16 is constituted by a plurality of magnets 16a arranged in a line has been described. However, in one embodiment of the present invention, the magnet portion 16 is constituted by a plurality of magnets arranged in a plurality of rows. That is, a plurality of magnets are arranged so as to be arranged in a plurality of rows in the third direction D3. Hereinafter, a specific description will be given with reference to the drawings.

[0060] (Magnetic field orientation device according to an embodiment) FIG. 10 is a diagram for explaining a magnetic field orientation device according to an embodiment of the present invention. (a) is a perspective view showing the magnetic field orientation device, and (b) is a view of the magnet portion as seen from the first direction D1. In the present embodiment, the pair of first yoke portions 34a and the pair of second yoke portions 34b of the yoke 34 are integrally formed.

[0061] As shown in FIG. 10, in the present embodiment, each magnet portion 16 includes a plurality of magnet rows 161 to 164 arranged in the third direction D3. The plurality of magnet rows 161 to 164 are each constituted by a plurality of rectangular parallelepiped magnets 16a provided so as to be arranged in the second direction D2. That is, in the present embodiment, a plurality of magnets 16a are arranged so as to be arranged in a plurality of rows in the third direction D3.

[0062] In each of the magnet rows 161 to 164, the boundary portions 16b between the magnets 16a adjacent to each other in the second direction D2 exist so as to extend in the third direction D3. In the present embodiment, in each of the magnet rows 161 to 164, a plurality of boundary portions 16b extending in the third direction D3 exist so as to be arranged in the second direction D2.

[0063] Among the plurality of magnet rows 161 to 164, a plurality of magnets 16a in one magnet row and a plurality of magnets 16a in another magnet row adjacent to the one magnet row are arranged so as to be shifted from each other in the second direction D2. In other words, the plurality of magnets 16a of the magnet section 16 are arranged in a staggered pattern. In the present embodiment, the plurality of magnets 16a of each magnet row 161 to 164 are arranged so as to be shifted in the second direction D2 with respect to the plurality of magnets 16a of the other plurality of magnet rows. For example, the plurality of magnets 16a of the magnet row 161 are arranged so as to be shifted in the second direction D2 with respect to the plurality of magnets 16a of the other plurality of magnet rows 162 to 164. As a result, a plurality of boundary portions 16b in one magnet row among the plurality of magnet rows 161 to 164 and a plurality of boundary portions 16b in the other plurality of magnet rows among the plurality of magnet rows 161 to 164 are shifted from each other in the second direction D2.

[0064] Since the magnet 16a is a hard metal part, when the magnet 16a has a rectangular parallelepiped shape, chipping is likely to occur at the ridge line portion of the magnet 16a. When chipping occurs at the ridge line portion of the magnet 16a, the plating applied to the surface of the magnet 16a may peel off, and rust may occur from the portion where the plating has peeled off. For this reason, it is preferable to chamfer the ridge line portion of the magnet 16a. On the other hand, by chamfering the ridge line portion of the magnet 16a, in the magnet section 16, a plurality of boundary portions 16b are recessed compared to other portions. In the portion where this depression is formed, the magnetic force of the magnet section 16 slightly decreases. As a result, magnetization unevenness occurs in the workpiece W (FIG. 2).

[0065] In view of the above points, in the present embodiment, as described above, a plurality of magnets 16a of one magnet row among the plurality of magnet rows 161 to 164 and a plurality of magnets 16a of another magnet row adjacent to the magnet row are arranged so as to be displaced from each other in the second direction D2. As a result, it is possible to prevent a portion (boundary portion 16b) where the magnetic force decreases in the magnet portion 16 from continuously existing in the third direction D3 across the plurality of magnet rows 161 to 164. In other words, a portion (boundary portion 16b) where the magnetic force decreases in one magnet row among the plurality of magnet rows 161 to 164 can be compensated by the magnetic force of the magnets 16a in another magnet row adjacent to the magnet row. As a result, in the work W (FIG. 2), it is possible to prevent a portion where the magnetization state is weak from occurring so as to continuously extend in the third direction D3 (work conveyance direction), and it is possible to reduce the magnetization unevenness of the work W.

[0066] In the example shown in FIG. 10, the positions of the plurality of magnets 16a of one magnet row 161 facing the first direction D1 in the second direction D2 and the positions of the plurality of magnets 16a of the other magnet row 161 in the second direction D2 are equal to each other. The same applies to the positional relationship in the second direction D2 between the plurality of magnets 16a of one magnet row 162 to 164 facing the first direction D1 and the plurality of magnets 16a of the other magnet row 162 to 164. However, the plurality of magnets 16a of one magnet row facing the first direction D1 and the plurality of magnets 16a of the other magnet row may be arranged so as to be displaced in the second direction D2.

[0067] When the magnet portion 16 is constituted by a plurality of magnets 16a arranged in a row, it is preferable that the plurality of magnets 16a of one magnetic field orientation device 32 among the plurality of magnetic field orientation devices 32 and the plurality of magnets 16a of another magnetic field orientation device 32 adjacent to the magnetic field orientation device 32 are arranged so as to be displaced from each other in the second direction D2. As a result, similar to the case of using the magnetic field orientation device 32 shown in FIG. 10, it is possible to reduce the magnetization unevenness of the work W.

[0068] (Other reference examples) Alternatively, the magnet portion 16 may be configured by arranging rectangular parallelepiped magnets extending in the second direction D2 in the third direction D3. Also, in the above-described embodiment, the case where the magnet portion 16 is composed of a plurality of magnets 16a has been described, but the magnet portion 16 may be composed of a single magnet.

[0069] FIG. 11 is a diagram showing a magnetic field orientation device 32 according to Reference Example 3. Note that FIG. 11 shows the magnetic field orientation device 32 as viewed from the first direction D1. The magnetic field orientation device 32 shown in FIG. 11 is different from the magnetic field orientation device 32 shown in FIG. 8 in that the length of the first yoke portion 34a in the third direction D3 is shorter at the central portion in the second direction D2. Thus, depending on the position in the second direction D2, the length of the first yoke portion 34a in the third direction D3 may be shorter. When the length of the first yoke portion 34a in the third direction D3 or the length of the magnet portion 16 in the third direction D3 changes depending on the position in the second direction D2, regardless of the position in the second direction D2, in a cross section orthogonal to the second direction D2 and passing through the magnet portion 16 and the first yoke portion 34a, it is preferable that the length of the first yoke portion 34a in the third direction D3 is 1.1 times or more the length of the magnet portion 16 in the third direction D3, and more preferably 1.6 times or more. Therefore, in the magnetic field orientation device 32 shown in FIG. 11, in both the B-B cross section and the C-C cross section, it is preferable that the length of the first yoke portion 34a in the third direction D3 is 1.1 times or more the length of the magnet portion 16 in the third direction D3, and more preferably 1.6 times or more.

[0070] (Modification example) FIG. 12 is a perspective view showing a magnetic field orientation unit including a magnetic field orientation device according to a modification example. As shown in FIG. 12, the magnetic field orientation unit 20 according to this modification example includes a plurality of magnetic field orientation devices 22. The plurality of magnetic field orientation devices 22 are arranged to be aligned in the conveyance direction A (see FIG. 2) of the workpiece W, similar to the plurality of magnetic field orientation devices 14 described above.

[0071] Each magnetic field orientation device 22 includes a pair of magnet parts 24 and a yoke 26 that holds the pair of magnet parts 24. The pair of magnet parts 24 are magnetized in the first direction D1. The pair of magnet parts 24 are arranged such that opposite poles face each other and are spaced apart from each other in the first direction D1. Thereby, a unidirectional magnetic field is generated between the pair of magnet parts 24 from one magnet part 24 toward the other magnet part 24. In this modification, when the work W (see FIG. 2) passes through the gap between the pair of magnet parts 24, a magnetic field is applied to the work W. Note that the distance between the pair of magnet parts 24 in the first direction D1 is appropriately adjusted according to the type, use, etc. of the work W. Since the magnet part 24 can be configured in the same manner as the above-described magnet part 16, a detailed description of the magnet part 24 is omitted.

[0072] The yoke 26 is made of a magnetic material such as steel, similar to the above-described yoke 18. In this modification, the yoke 26 has a C-shaped (U-shaped) configuration when viewed from the third direction D3. Specifically, the yoke 26 includes a pair of first yoke parts 26a and a second yoke part 26b. Each of the pair of first yoke parts 26a is supported by the second yoke part 26b in a cantilever manner. In FIG. 12, the boundary between the first yoke part 26a and the second yoke part 26b is indicated by a dashed line.

[0073] In this modification, the first yoke part 26a has a uniform part 61 and a decreasing part 62 in order from one side in the second direction D2. In this modification, the uniform parts 61 of the pair of first yoke parts 26a are connected by the second yoke part 26b. The uniform part 61 is a part where the area of the cross section orthogonal to the second direction D2 of the first yoke part 26a is uniform. The decreasing part 62 is a part where the area of the cross section orthogonal to the second direction D2 continuously decreases from the second yoke part 26b (uniform part 61) side toward the tip 63 of the first yoke part 26a. Note that in this modification, the length of the decreasing part 62 in the third direction D3 decreases stepwise from the second yoke part 26b side toward the tip 63, and the length of the decreasing part 62 in the first direction D1 continuously decreases from the second yoke part 26b side toward the tip 63.

[0074] A magnet portion 24 is fixed to each of a pair of first yoke portions 26a. The second yoke portion 26b is provided outside the pair of magnet portions 24 in the second direction D2 and connects the pair of first yoke portions 26a.

[0075] Similar to the above-described magnetic field orientation device 14, also in the magnetic field orientation device 22 according to this modification example, when viewed from the first direction D1, the outer edge of the magnet portion 24 is positioned inside the outer edge of the first yoke portion 26a. Similar to the above-described magnetic field orientation device 14, in the third direction D3, the length of the first yoke portion 26a is preferably 1.1 times or more, and more preferably 1.6 times or more, the length of the magnet portion 24. Also in this modification example, the length of the second yoke portion 26b in the third direction D3 is set in the same manner as the length of the first yoke portion 26a.

[0076] (Operation and Effect) Also in the magnetic field orientation device 22 according to this modification example, when viewed from the first direction D1, the outer edge of the magnet portion 24 is positioned inside the outer edge of the first yoke portion 26a. Thereby, it is possible to suppress the leakage of magnetic flux radially from the end face side (the end face fixed to the first yoke portion 26a) on the first yoke portion 26a side of the magnet portion 24. As a result, when a plurality of magnetic field orientation devices 22 are arranged in the conveyance direction A, it is possible to prevent a large repulsive force from being generated between the magnetic field orientation devices 22 adjacent to each other in the conveyance direction A. Thereby, the close installation of each magnetic field orientation device 22 becomes easy. Also, similar to the above-described magnetic field orientation device 14, the intensity of the demagnetizing field can be made sufficiently low.

[0077] Further, the magnetic field orientation device 22 according to this modification example has a yoke 26 having a C-shaped (U-shaped) shape when viewed from the third direction D3. Thereby, for example, since the magnetic field orientation device 22 can be fitted into the conveyor belt 104 from the side of the conveyor belt 104, the installation of the magnetic field orientation device 22 becomes even easier. Also, when arranging a plurality of magnetic field orientation devices 22, any one of the magnetic field orientation devices 22 and another magnetic field orientation device 22 can be fitted into the conveyor belt 104 from the opposite side in the second direction D2. Thereby, the degree of freedom in arranging the magnetic field orientation devices 22 is improved.

[0078] In the magnetic field orientation device 22 according to this modified example, the first yoke portion 26a is supported by the second yoke portion 26b in a cantilever manner. In this case, the amount of magnetic flux passing through the tip end portion 63 side of the first yoke portion 26a is less than the amount of magnetic flux passing through the second yoke portion 26b side of the first yoke portion 26a. For this reason, even if the cross-sectional area of the tip end portion 63 side of the first yoke portion 26a is made smaller than the cross-sectional area of the second yoke portion 26b side of the first yoke portion 26a, the flow of magnetic flux is not obstructed. Therefore, in this modified example, a reducing portion 62 is provided on the tip end portion 63 side of the first yoke portion 26a. Thereby, the volume of the first yoke portion 26a can be reduced without obstructing the flow of magnetic flux. As a result, the weight of the magnetic field orientation device 22 can be reduced without degrading the performance of the magnetic field orientation device 22.

[0079] In the above-described modified example, in the reducing portion 62, the area of the cross-section orthogonal to the second direction D2 continuously decreases from the second yoke portion 26b side toward the tip end portion 63, but the area of the cross-section orthogonal to the second direction D2 may decrease stepwise from the second yoke portion 26b side toward the tip end portion 63.

Industrial Applicability

[0080] According to the present invention, a magnetic field orientation device that is easy to install and a magnetic field orientation unit including the same can be obtained.

Explanation of Reference Numerals

[0081] 1, 10 Facilities 12, 20, 30 Magnetic field orientation units 14, 22, 32 Magnetic field orientation devices 16, 24 Magnet portions 18, 26, 34 Yokes 18a, 26a, 34a First yoke portions 18b, 26b, 34b Second yoke portions

Claims

1. A pair of magnet parts arranged such that opposite poles face each other in a first direction and are spaced apart from each other, and a yoke for holding the pair of magnet parts, wherein the yoke, has a pair of first yoke parts provided outside the pair of magnet parts in the first direction and to which the magnet parts are respectively fixed, and a second yoke part provided outside the pair of magnet parts in a second direction orthogonal to the first direction and connecting the pair of first yoke parts, when viewed from the first direction, the outer edge of the magnet part is positioned inside the outer edge of the first yoke part, the magnet part includes a plurality of magnet rows arranged in a third direction orthogonal to the first direction and the second direction, each of the magnet rows includes a plurality of magnets arranged in the second direction, a magnetic field orientation device in which the plurality of magnets in one of the plurality of magnet rows and the plurality of magnets in another magnet row adjacent to the one magnet row are arranged so as to be shifted from each other in the second direction.

2. The magnetic field orientation device according to claim 1, wherein the second yoke part is provided on one side and the other side of the pair of magnet parts in the second direction, respectively.

3. The yoke has a C-shaped cross-section when viewed from a third direction orthogonal to the first direction and the second direction, and each of the pair of first yoke parts is supported by the second yoke part in a cantilever manner. The magnetic field orientation device according to claim 1.

4. Among the first yoke parts, when the end portion on the side opposite to the second yoke part in the second direction is taken as the tip end portion, the first yoke part includes a decreasing portion in which the cross-sectional area in a cross-section orthogonal to the second direction continuously or stepwise decreases from the second yoke part side toward the tip end portion. The magnetic field orientation device according to claim 3.

5. In a third direction orthogonal to the first direction and the second direction, the length of the first yoke part is 1.1 times or more the length of the magnet part. The magnetic field orientation device according to claim 1.

6. In a third direction orthogonal to the first direction and the second direction, the length of the first yoke part is 1.6 times or more the length of the magnet part. The magnetic field orientation device according to claim 1.

7. In a third direction orthogonal to the first direction and the second direction, the length of the second yoke part is longer than the length of the magnet part. The magnetic field orientation device according to claim 1.

8. A magnetic field orientation unit includes a plurality of magnetic field orientation devices each having a pair of magnet portions arranged such that unlike poles face each other and are spaced apart from each other in a first direction, and a yoke holding the pair of magnet portions. The yoke includes a pair of first yoke portions provided outside the pair of magnet portions in the first direction and each having the magnet portion fixed thereto, and a second yoke portion provided outside the pair of magnet portions in a second direction orthogonal to the first direction and connecting the pair of first yoke portions. When viewed from the first direction, the outer edge of the magnet portion is positioned inside the outer edge of the first yoke portion. The plurality of magnetic field orientation devices are arranged side by side in a third direction orthogonal to the first direction and the second direction. The magnet portion of each magnetic field orientation device includes a plurality of magnets arranged side by side in the second direction. The plurality of magnets of one magnetic field orientation device among the plurality of magnetic field orientation devices and the plurality of magnets of another magnetic field orientation device adjacent to the one magnetic field orientation device are arranged so as to be offset from each other in the second direction.

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