Magnetic field orientation device and magnetic field orientation unit

Abstract

To provide a magnetic field orientation device that facilitates installation.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 separated from 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 that are provided on the outside the pair of magnet portions 16 in the first direction D1 and to which the magnet portions 16 are fixed, and a pair of second yoke portions 34b that are provided outside the pair of magnet portions 16 in a second direction D2 orthogonal to the first direction D1 and connect 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. A recess 36 is formed in the central portion of the first yoke portions 34a in the second direction D2 so as to be concave toward the magnet portion 16 in the first direction D1.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a magnetic field orientation device for applying 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 the workpiece (in Patent Document 1, a strip-shaped non-magnetic support coated with a magnetic paint) so that opposite poles face each other, and it is conceivable to apply a magnetic field to the workpiece while conveying the workpiece. When applying a magnetic field to a workpiece in this way using a magnet, 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, when applying a high-intensity magnetic field to the workpiece, it is necessary to use a powerful magnet.

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, but it is difficult to form a strong 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 inventors, it has been found that when attempting to arrange strong magnets so as to be aligned in the transport direction of the workpiece, a large repulsive force is generated between adjacent magnets, and the magnets cannot be easily installed.

[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 such that unlike poles face each other and 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 each having the magnet part fixed thereto; A pair of second yoke parts provided on one side and the other side of 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. A recess that is recessed toward the magnet part side in the first direction is formed at the central part of each of the first yoke parts in the second direction.

[0010] The magnetic field orientation unit according to another aspect of the present invention includes a plurality of the magnetic field orientation devices. The plurality of magnetic field orientation devices are arranged to be aligned in a third direction orthogonal to the first direction and 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

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0013] (Examination by the inventor of the present invention) The inventor examined a method of applying a magnetic field to a workpiece using magnets. FIG. 1 is a diagram for explaining the examination content by the inventor of the present invention. 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 conveying device 100 for conveying the workpiece W and a plurality of magnet units 200 for applying a magnetic field to the workpiece W.

[0014] The conveying device 100 includes a plurality of rollers 102 and a conveying belt 104 supported by the plurality of rollers 102. The conveying belt 104 is driven by a drive source (not shown), and conveys the workpiece W on the conveying belt 104 in the direction indicated by the arrow A (hereinafter referred to as the conveying 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. The magnet 202 is provided on one side of the conveying belt 104, and the magnet 204 is provided on the other side of the conveying belt 104. In each magnet unit 200, the 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 the magnet 204 to the magnet 202) is generated between the magnet 202 and the magnet 204.

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

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

[0018] The inventor further proceeded with the study and considered providing a yoke so as to sandwich the 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 the magnets adjacent to each other 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 the pair of magnets from above and below so that the pair of magnets do not protrude from the yoke in the conveying direction A, the repulsive force generated between the magnets adjacent to each other in the conveying direction A can be sufficiently reduced.

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

[0020] (Reference Example 1) FIG. 2 is a schematic view showing a facility including 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 includes 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 side by side in the conveying direction A of the workpiece W. In FIG. 3, a first direction D1, a second direction D2, and a third direction D3 orthogonal to each other are shown. The third direction D3 is a direction parallel to the conveying direction A. In other drawings, the first direction D1, the second direction D2, and the third direction D3 are appropriately shown.

[0022] A cavity for passing the conveyor belt 104 and the workpiece W (see FIG. 2) supported by the conveyor belt 104 is formed in 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. (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 portions 16 are magnetized in the first direction D1. The pair of magnet portions 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 portions 16 from one magnet portion 16 toward the other magnet portion 16. In this Reference Example 1, when the workpiece W (see FIG. 2) passes through the gap between the pair of magnet portions 16, a magnetic field is applied to the workpiece W. Note that the distance between the pair of magnet portions 16 in the first direction D1 is appropriately adjusted according to the type and use of the workpiece W, etc. In this Reference Example 1, the distance between the pair of magnet portions 16 is set to, for example, 10 mm.

[0025] In this Reference Example 1, the magnet portion 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 portion 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 a pair of magnet portions 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 made of a magnetic material such as steel. 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 portion 16 is fixed to the first yoke portion 18a by an adhesive.

[0028] In this Reference Example 1, of 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 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 beyond both sides of the magnet portion 16 in the third direction D3. In the present Reference Example 1, in the third direction D3, it is preferable that the length b of the first yoke portion 18a is 1.1 times or more, and more preferably 1.6 times or more, the length a of the magnet portion 16. In the present 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 the present Reference Example 1, it is preferable that the length c of the first yoke portion 18a in the first direction D1 is set to be 0.5 to 3.5 times the length b of the first yoke portion 18a in the third direction D3. Also, it is preferable that the length d of the second yoke portion 18b in the second direction D2 is set to be 0.5 to 3.5 times the length of the second yoke portion 18b in the third direction D3.

[0030] (Operational effects of Reference Example 1) In the magnetic field orientation device 14 according to the present 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 first yoke portion 18a side 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 the magnetic field orientation devices 14 in close proximity to each other.

[0031] FIG. 5 is a diagram showing an example of the strength of the magnetic field generated by the 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. 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 side by side 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 exhibit four peaks. Here, as shown in the portion surrounded by the dashed-dotted 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, as described above, it is possible to suppress magnetic flux from leaking radially from the end surface 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 is no particular limitation on the workpiece W. Examples of the workpiece W include rubber magnets, magnetic paints, magnetic fluids, semiconductor wafers, polymer slurries containing magnetic particles, film-shaped electrodes, and the like. In the above-described first reference example, the workpiece W is transported by the transport belt 104. However, when applying a magnetic field to a belt-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 simulation using electromagnetic field analysis software (JMAG manufactured by JSOL Corporation) for the above-described 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, and magnetic field analysis was performed. Then, the magnetic flux density of the reverse magnetic 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 in the third direction D3 (conveying direction A) were obtained. The area of the cross section of the first yoke portion 18a orthogonal to the second direction D2 and the area of the cross section 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 by arranging 11 magnets 16a (neodymium magnets) 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 length b and the length 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 demagnetization ratio represents the ratio of the magnitude (absolute value) of the magnetic flux density of the demagnetizing field and the magnitude (absolute value) of the magnetic flux density of the unidirectional magnetic field 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. Also, 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 Reference Example 1 described above. 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). Also, Fig. 7 shows the relationship between the value of the ratio of the length b and the length 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 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 demagnetizing 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 demagnetizing 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 arranging a plurality of magnetic field orientation devices 14 in proximity to each other. On the other hand, the inventor considered reducing the weight 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 decrease the amount of magnetic flux passing through the yoke, potentially making it impossible to ensure a sufficient magnetic flux density for the unidirectional magnetic field. Therefore, the inventor of the present invention conducted a detailed study on a configuration for reducing the weight of the yoke while suppressing a decrease in the magnetic flux density of the unidirectional magnetic field. During 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 through 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 through which almost no magnetic flux flows from the yoke, it would be possible to reduce the weight of the yoke while suppressing a decrease in the magnetic flux density of the unidirectional magnetic field.

[0042] The present invention has been completed based on the above findings. Hereinafter, a magnetic field orientation device according to an embodiment of the present invention and a 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 the Embodiment) FIG. 8 is a perspective view showing a magnetic field orientation unit including a magnetic field orientation device according to an embodiment of the present invention. As shown in FIG. 8, the magnetic field orientation unit 30 according to the present embodiment is configured to be able to apply a magnetic field to a workpiece W (see FIG. 2) conveyed by a conveyor belt 104, similar 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 as well, the first direction D1, the second direction D2, and the third direction D3 are appropriately shown.

[0045] At the center 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 embodiment, the conveyor belt 104 and the workpiece W pass between a pair of magnet portions 16 disposed 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 portions 16 and a yoke 34 that holds the pair of magnet portions 16. The yoke 34 is provided so as to surround the pair of magnet portions 16. A cavity 35 penetrating in the third direction D3 is formed at the center of the yoke 34. 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 portions 34a and a pair of second yoke portions 34b. In the present embodiment, the pair of first yoke portions 34a and the pair of second yoke portions 34b are each constituted by separate members. Note that, as in the yoke 34 shown in FIG. 10 described later, the pair of first yoke portions 34a and the pair of second yoke portions 34b may be integrally formed. That is, in the present embodiment, the yoke 34 is constituted by a plurality of members, but the yoke 34 may be constituted by a single member.

[0048] As shown in FIGS. 8 and 9, in the present embodiment, a pair of first yoke portions 34a are provided outside a pair of magnet portions 16 in the first direction D1. The magnet portions 16 are fixed to the pair of first yoke portions 34a, respectively. In the present embodiment, the magnet portions 16 are fixed to the first yoke portions 34a by, for example, 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 by, for example, an adhesive.

[0049] At the central portion of each first yoke portion 34a in the second direction D2, a concave portion 36 that is recessed toward the magnet portion 16 side in the first direction D1 is formed. In the present embodiment, the concave portion 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 the present embodiment, a 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 concave portion 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] Further, in the present embodiment, corner portions 34d (outer corner portions 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-shaped surface. 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-mentioned 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 on both sides of the magnet portion 16 in the third direction D3. Also in this embodiment, similar to the above-mentioned 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)). In addition, also in this embodiment, 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] (Operation and Effect of this Embodiment) Also in the magnetic field orientation device 32 according to this embodiment, similar to the magnetic field orientation device 14 according to the above-mentioned 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 occurring between the magnetic field orientation devices 32 adjacent to each other in the transport direction A. Thereby, the close installation of each magnetic field orientation device 32 becomes easy. Further, since the 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 the present embodiment, 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 the present embodiment, 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 impeded. That is, in the present embodiment, the volume of the yoke 34 (first yoke portion 34a) can be reduced without impeding 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 the present embodiment, the magnetic flux generated by the pair of magnet portions 16 flows in the first yoke portion 34a from the inner side to the outer side (or from the outer side to the inner side) 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 the present embodiment, 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 a cross-section orthogonal 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 the present embodiment, the corner portions 34d of each first yoke portion 34a have a shape that is notched 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 reference to the yoke 18 shown in FIG. 4, the amount of magnetic flux passing through the four corners of the yoke 18 is smaller than the amount of magnetic flux passing through the other portions of the first yoke portion 18a (see FIG. 4). Therefore, in the present embodiment, even if the corner portions 34d of each first yoke portion 34a have a notched shape, the flow of magnetic flux in the yoke 34 is not inhibited. That is, the volume of the yoke 34 can be reduced without inhibiting 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] (Modification example) In the yoke 34 shown in FIG. 9, the 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 portion 34d of the first yoke portion 34a has a shape that is notched in a C-plane shape. However, the shape of the corner portion 34d is not limited to the above example. For example, the corner portion 34d may have a shape that is notched 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-described embodiment, the case where the magnet portion 16 is configured by a plurality of magnets 16a arranged in a row has been described. However, the magnet portion 16 may be configured by a plurality of magnets arranged in a plurality of rows. That is, the plurality of magnets may be 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] FIG. 10 is a diagram for explaining a magnetic field orientation device according to a modified example. (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, the 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, the plurality of magnets 16a of one magnet row and the plurality of magnets 16a of 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, the plurality of boundary portions 16b of one magnet row among the plurality of magnet rows 161 to 164 and the plurality of boundary portions 16b of 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, the plurality of boundary portions 16b are recessed compared to other portions. In the portion where this recess 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 in the second direction D2 of the plurality of magnets 16a in one magnet row 161 facing the first direction D1 and the positions in the second direction D2 of the plurality of magnets 16a in the other magnet row 161 are equal to each other. The same applies to the positional relationship in the second direction D2 between the plurality of magnets 16a in one magnet row 162 to 164 facing the first direction D1 and the plurality of magnets 16a in the other magnet row 162 to 164. However, the plurality of magnets 16a in one magnet row facing the first direction D1 and the plurality of magnets 16a in the other magnet row may be arranged so as to be displaced from each other 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] Further, 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 configured by a plurality of magnets 16a has been described, but the magnet portion 16 may be configured by a single magnet.

[0069] FIG. 11 is a diagram showing a magnetic field orientation device 32 according to another modification. 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] (Reference Example 2) FIG. 12 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. 12, the magnetic field orientation unit 20 according to Reference Example 2 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 portions 24 and a yoke 26 that holds the pair of magnet portions 24. The pair of magnet portions 24 are magnetized in the first direction D1. The pair of magnet portions 24 are arranged such that opposite poles face each other and are spaced apart from each other in the first direction D1. As a result, a unidirectional magnetic field is generated between the pair of magnet portions 24 from one magnet portion 24 toward the other magnet portion 24. In this reference example 2, when the work W (see FIG. 2) passes through the gap between the pair of magnet portions 24, a magnetic field is applied to the work W. Note that the distance between the pair of magnet portions 24 in the first direction D1 is appropriately adjusted according to the type, use, etc. of the work W. Since the magnet portion 24 can be configured in the same manner as the above-described magnet portion 16, a detailed description of the magnet portion 24 is omitted.

[0072] The yoke 26 is made of a magnetic material such as a steel material, similarly to the above-described yoke 18. In this reference example 2, the yoke 26 has a C shape (U shape) when viewed from the third direction D3. Specifically, the yoke 26 includes a pair of first yoke portions 26a and a second yoke portion 26b. Each of the pair of first yoke portions 26a is supported by the second yoke portion 26b in a cantilever manner. In FIG. 12, the boundary between the first yoke portion 26a and the second yoke portion 26b is indicated by a dashed line.

[0073] In this reference example 2, the first yoke portion 26a has a uniform portion 61 and a decreasing portion 62 in order from one side in the second direction D2. In this reference example 2, the uniform portions 61 of the pair of first yoke portions 26a are connected by the second yoke portion 26b. The uniform portion 61 is a portion where the area of the cross section orthogonal to the second direction D2 of the first yoke portion 26a is uniform. The decreasing portion 62 is a portion where the area of the cross section orthogonal to the second direction D2 continuously decreases from the second yoke portion 26b (uniform portion 61) side toward the tip portion 63 of the first yoke portion 26a. Note that in this reference example 2, the length of the decreasing portion 62 in the third direction D3 decreases stepwise from the second yoke portion 26b side toward the tip portion 63, and the length of the decreasing portion 62 in the first direction D1 continuously decreases from the second yoke portion 26b side toward the tip portion 63.

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

[0075] Similar to the above-described magnetic field orientation device 14, in the magnetic field orientation device 22 according to this reference example 2, when viewed from the first direction D1, the outer edge of the magnet part 24 is positioned inside the outer edge of the first yoke part 26a. Similar to the above-described magnetic field orientation device 14, in the third direction D3, the length of the first yoke part 26a is preferably 1.1 times or more, and more preferably 1.6 times or more, the length of the magnet part 24. Also in this reference example 2, the length of the second yoke part 26b in the third direction D3 is set in the same manner as the length of the first yoke part 26a.

[0076] (Function and Effect) Also in the magnetic field orientation device 22 according to this reference example 2, when viewed from the first direction D1, the outer edge of the magnet part 24 is positioned inside the outer edge of the first yoke part 26a. Thereby, it is possible to suppress the leakage of magnetic flux radially from the end face (the end face fixed to the first yoke part 26a) on the first yoke part 26a side of the magnet part 24. As a result, when a plurality of magnetic field orientation devices 22 are arranged in the transport direction A, it is possible to prevent a large repulsive force from occurring between the magnetic field orientation devices 22 adjacent to each other in the transport 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 reference example 2 has a yoke 26 having a C shape (U shape) when viewed from the third direction D3. Thereby, for example, the magnetic field orientation device 22 can be fitted into the conveyor belt 104 from the side of the conveyor belt 104, so that the installation of the magnetic field orientation device 22 becomes even easier. Also, when arranging a plurality of magnetic field orientation devices 22, one magnetic field orientation device 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 the second reference 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 hindered. Therefore, in the second reference 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 hindering 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 second reference 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 Signs

[0081] 1, 10 Facilities 12, 20, 30 Magnetic field orientation unit 14, 22, 32 Magnetic field orientation device 16, 24 Magnet portion 18, 26, 34 Yoke 18a, 26a, 34a First yoke portion 18b, 26b, 34b Second yoke portion

Claims

1. A pair of magnet parts arranged such that unlike poles face each other and are spaced apart from each other in a first direction, and a yoke that holds 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 pair of second yoke parts provided on one side and the other side of 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, A magnetic field orientation device, wherein a recess that is recessed toward the magnet part side in the first direction is formed at the central part of each of the first yoke parts in the second direction.

2. The magnetic field orientation device according to claim 1, wherein the recess is formed such that the length of each of the first yoke parts in the first direction becomes continuously or stepwise longer as it moves away from the center of the magnet part in the second direction.

3. The magnetic field orientation device according to claim 1, wherein the length of both ends of the yoke in the first direction is shorter toward the outside in the second direction.

4. The magnetic field orientation device according to claim 1, wherein 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.

5. The magnetic field orientation device according to claim 1, wherein 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.

6. The magnetic field orientation device according to claim 1, wherein 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.

7. 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, The magnetic field orientation device according to claim 1, wherein 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 displaced from each other in the second direction.

8. Comprising a plurality of the magnetic field orientation devices described in claim 1, The plurality of magnetic field orientation devices are arranged to be aligned in a third direction orthogonal to the first direction and the second direction, and the magnetic field orientation unit. **Claim 9** The magnet part of each of the magnetic field orientation devices includes a plurality of magnets provided to be aligned in the second direction. The plurality of magnets of one of 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 to be displaced from each other in the second direction. The magnetic field orientation unit according to claim 8.

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