Magnet body, magnet part, and method for manufacturing the magnet body

Abstract

To provide a magnet that suppresses separation of one magnet piece from the other magnet piece as compared with a case where a pair of magnet pieces with the same polarity are adhered with one kind of adhesive and the adhesive is in contact with the outside air, and a magnet portion, and a manufacturing method for the magnet.SOLUTION: A magnet 10 includes one magnet piece 14, another magnet piece 24 arranged adjacent to the one magnet piece 14 and having the same polarity as the one magnet piece 14, an adhesive 34 bonding the one magnet piece 14 and the other magnet piece 24, and a sealing portion 38 that surrounds and seals the adhesive 34.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a magnet body, a magnet section, and a method for manufacturing a magnet body. [Background technology]

[0002] In the magnetic roller described in Patent Document 1, the adhesive applied between the shaft and the magnet pieces is a cyanoacrylate instant adhesive containing 3% or more of a urethane rubber component, and the adhesive applied between the magnet pieces is a cyanoacrylate instant adhesive or an acrylic adhesive. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-059966 Summary of the Invention [Problem to be solved by the invention]

[0004] By bonding a pair of magnet pieces of the same polarity with a single type of adhesive, a single magnet body with strong magnetic force is obtained. Because the pair of magnet pieces are of the same polarity, a repulsive force acts on the adhesive at the bonded portion of the magnet body. If the end faces of the adhesive are exposed to the outside air, the adhesive may deteriorate due to changes in temperature and humidity, causing one magnet piece to peel off from the other.

[0005] The object of the present invention is to prevent one magnet piece from peeling off from the other magnet piece, compared to when a pair of magnet pieces of the same polarity are bonded with a single type of adhesive and the adhesive is exposed to the outside air. [Means for solving the problem]

[0006] The magnet body according to the first aspect of the present invention is characterized by comprising one magnet piece, another magnet piece arranged adjacent to the one magnet piece and having the same polarity as the one magnet piece, an adhesive that bonds the one magnet piece to the other magnet piece, and a sealing portion that is arranged surrounding the adhesive and seals the adhesive.

[0007] A magnet body according to a second aspect of the present invention is the magnet body according to the first aspect, characterized in that the sealing portion is a sealant applied to surround the adhesive.

[0008] A magnet body according to a third aspect of the present invention is the magnet body according to the second aspect, characterized in that the sealant is another adhesive agent having a lower hardness than the adhesive agent.

[0009] A magnet body according to a fourth aspect of the present invention is characterized in that, in the magnet body described in the second or third aspect, one of the magnet pieces has one adhesive surface formed thereon, the other magnet piece has another adhesive surface formed thereon that sandwiches the adhesive between the one adhesive surface and the other magnet piece, and at least a part of the outer periphery of the one adhesive surface has a chamfered portion formed thereon in which the applied sealant is placed.

[0010] A magnetic body according to a fifth aspect of the present invention is the magnetic body according to the fourth aspect, characterized in that the chamfered portion is formed around the entire outer periphery of the one bonding surface.

[0011] A magnet body according to a sixth aspect of the present invention is characterized in that, in the magnet body described in the fifth aspect, another chamfered portion is formed around the entire outer periphery of the other adhesive surface, in which the applied sealant is arranged.

[0012] The magnet part according to the seventh aspect of the present invention is characterized in that the magnet body described in claim 6, which is composed of one magnet piece that has a fan-shaped cross section, extends in one direction, and has one adhesive surface formed on its side, and another magnet piece that has a fan-shaped cross section, extends in one direction, and has the other adhesive surface formed on its side, is arranged in a fan shape in the circumferential direction of the magnet body when viewed from one direction, in three pieces, and that of the three magnet bodies, the central magnet body and the magnet bodies at both ends have different magnetic polarities.

[0013] A manufacturing method for a magnet body according to an eighth aspect of the present invention is characterized by comprising the steps of: preparing one magnet piece having a fan-shaped cross section, extending in one direction, and having one adhesive surface formed on a side surface; and another magnet piece having a fan-shaped cross section, extending in one direction, and having another adhesive surface formed on a side surface; contacting the one adhesive surface and the other adhesive surface so that the same poles face each other, positioning the one magnet piece and the other magnet piece on their inner circumferential surfaces, and injecting adhesive between the one adhesive surface and the other adhesive surface from the outer circumferential surface side to bond the one magnet piece and the other magnet piece; and applying a sealant to the one magnet piece and the other magnet piece so as to surround the adhesive and seal the adhesive. [Effects of the Invention]

[0014] According to the first embodiment of the magnet body of the present invention, it is possible to prevent one magnet piece from peeling off from the other magnet piece, compared to when a pair of magnet pieces of the same polarity are bonded with a single type of adhesive and the adhesive is exposed to the outside air.

[0015] According to the magnet body of the second aspect of the present invention, compared to when the adhesive is enclosed and sealed using tape, it is possible to prevent the occurrence of portions where the adhesive is not sealed by the sealing portion.

[0016] The magnet body of the third aspect of the present invention can prevent one magnet piece from peeling off from the other magnet piece, compared to when a gel sealant that does not harden over time is used.

[0017] According to the magnet body of the fourth aspect of the present invention, compared to when a sealant is disposed between the bonding surfaces, it is possible to prevent the occurrence of areas where the adhesive is not sealed by the sealant.

[0018] According to the magnet body of the fifth aspect of the present invention, compared to when the chamfered portion is formed only partially, it is possible to prevent the occurrence of portions where the adhesive is not sealed by the sealant.

[0019] According to the magnet body of the sixth aspect of the present invention, compared to when a chamfered portion is formed on only one magnet piece, it is possible to reduce the occurrence of areas where the adhesive is not sealed by the sealant.

[0020] According to the magnet section of the seventh aspect of the present invention, when the central magnet body of the three magnet bodies is an N pole and the magnet bodies on both ends are S poles, the magnetic flux density of the central N pole can be made larger than when S pole magnet bodies made of a single magnet piece are placed at both ends of an N pole magnet body made of a single magnet piece. Also, when the central magnet body of the three magnet bodies is an S pole and the magnet bodies on both ends are N poles, the magnetic flux density of the central S pole can be made smaller than when N pole magnet bodies made of a single magnet piece are placed at both ends of an S pole magnet body made of a single magnet piece.

[0021] According to the eighth aspect of the method for manufacturing a magnet body of the present invention, it is possible to prevent one magnet piece from peeling off from the other magnet piece, compared to when manufacturing is completed with a process of bonding one magnet piece to another magnet piece. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is an exploded perspective view showing a pair of magnet pieces that constitute a magnet body according to an embodiment of the present invention. [Figure 2] 1A and 1B are cross-sectional views showing a magnet body according to an embodiment of the present invention. [Figure 3] FIG. 2 is a front view showing a magnet body according to an embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view showing a magnet portion according to an embodiment of the present invention. [Figure 5] FIG. 2 is a front view showing a magnet body that constitutes a magnet section according to an embodiment of the present invention. [Figure 6] 1A and 1B are cross-sectional views showing a magnet body that constitutes a magnet section according to an embodiment of the present invention. [Figure 7] 1A and 1B are process diagrams showing a method for manufacturing a magnet body according to an embodiment of the present invention. [Figure 8]FIG. 2 is a side view showing an example of a portion of a magnet body according to an embodiment of the present invention to which an adhesive is applied. [Figure 9] 1 is a schematic diagram illustrating a developing device including a magnet portion according to an embodiment of the present invention as a component part; [Figure 10] 1 is a schematic diagram showing a magnetic roll having a magnet section according to an embodiment of the present invention as a component part. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] An example of a magnet body, a magnet section, and a method for manufacturing a magnet body according to an embodiment of the present invention will be described with reference to FIGS.

[0024] (Magnetic body 10) As shown in Fig. 1, magnet body 10 includes magnet piece 14 and magnet piece 24. In Fig. 1, magnet piece 14 and magnet piece 24 are shown separated from each other so that the shapes of magnet piece 14 and magnet piece 24 can be easily seen. Magnet piece 14 is an example of one magnet piece, and magnet piece 24 is an example of the other magnet piece.

[0025] Furthermore, as shown in FIGS. 2(A) and 2(B), the magnet body 10 includes an adhesive 34 that bonds the magnet pieces 14 and 24 together, and an adhesive 38 that is applied around the adhesive 34. The adhesive 38 is an example of another adhesive, sealant, or sealing portion. FIG. 2(A) is a cross-sectional view of the magnet body 10 in which the magnet pieces 14 and 24 shown in FIG. 1 are bonded together with the adhesive 34 and 38, taken along a plane perpendicular to one direction (direction D in the figure). FIG. 2(B) is a cross-sectional view of the magnet body 10 in which the magnet pieces 14 and 24 shown in FIG. 1 are bonded together with the adhesive 34 and 38, taken along a plane perpendicular to bonding surfaces 20 and 30, which will be described later.

[0026] [Magnet piece 14, magnet piece 24] Magnet piece 14 and magnet piece 24 have the same polarity, and as shown in Figures 2(A) and 2(B), magnet piece 14 and magnet piece 24 are respectively formed with adhesive surfaces 20 and 30 to which adhesive 34 is applied. Adhesive 34 is sandwiched between adhesive surfaces 20 and 30, and magnet piece 14 and magnet piece 24 are symmetrical with respect to adhesive 34. Adhesive surface 20 is an example of one adhesive surface, and adhesive surface 30 is an example of the other adhesive surface.

[0027] The shape of the magnet pieces 14 will now be described. As shown in Fig. 1, the magnet pieces 14 extend in one direction (direction D in the figure) and have a sector-shaped cross section. Here, the sector shape is a concept that includes a shape formed by an outer peripheral arc on the radially outer side, an inner peripheral arc on the radially inner side, and a pair of side edges connecting both ends of the outer peripheral arc and both ends of the inner peripheral arc.

[0028] The magnet piece 14 has an outer peripheral surface 16a facing radially outward, an inner peripheral surface 16b facing radially inward, and a pair of end surfaces 18 facing one side and the other side in one direction. The magnet piece 14 also has an adhesive surface 20 facing one side when viewed from one direction, and a side surface 22 facing the other side when viewed from the same direction.

[0029] Furthermore, the adhesive surface 20 and the side surface 22 are rectangular and extend in one direction when viewed from the normal direction of each surface (see FIG. 8). Furthermore, a chamfered portion 23 is formed around the entire outer periphery of the adhesive surface 20. Here, the chamfered portion is a slanted surface or an arcuate surface provided at a corner (ridge line), and the slanted surface formed at the corner corresponds to a "C-chamfered portion," and the arcuate surface formed at the corner corresponds to an "R-chamfered portion."

[0030] The magnet piece 24, which is symmetrical to the magnet piece 14 across the adhesive 34, has an outer peripheral surface 26a, an inner peripheral surface 26b, a pair of end faces 28, an adhesive surface 30, a side surface 32, and a chamfered portion 33, just like the magnet piece 14. The chamfered portion 33 is an example of another chamfered portion.

[0031] 3, the magnetic field orientation direction (the direction of arrow G1 in the figure) from the south pole to the north pole inside magnet piece 14 is the direction from the portion of inner circumferential surface 16b on the side surface 22 side to the portion of outer circumferential surface 16a on the adhesive surface 20 side when viewed from one direction. In other words, when viewed from one direction, magnet piece 14 has an north pole (N1 in the figure) on the radially outer side and an south pole (S1 in the figure) on the radially inner side, and the boundary surface between the north pole and the south pole (dotted line in the figure) is perpendicular to the magnetic field orientation direction G1 from the south pole to the north pole.

[0032] Furthermore, the magnetic field orientation direction (the direction of arrow G2 in the figure) from the south pole to the north pole inside magnet piece 24 is symmetrical to the magnetic field orientation direction G1 of magnet piece 14 across adhesive 34. In other words, magnetic field orientation direction G2 inside magnet piece 24 is the direction from the portion of inner circumferential surface 26b on the side of side surface 32 to the portion of outer circumferential surface 26a on the side of adhesive surface 30 when viewed from one direction. In other words, when viewed from one direction, magnet piece 24 has an north pole (N2 in the figure) on the radially outer side and an south pole (S2 in the figure) on the radially inner side, and the boundary surface between the north pole and the south pole (dotted line in the figure) is perpendicular to the magnetic field orientation direction G2 from the south pole to the north pole.

[0033] In this way, magnet piece 14 and magnet piece 24 are arranged with the same poles (N1 and N2 facing each other, S1 and S2 facing each other) facing each other across adhesive 34. In other words, in this embodiment, "magnet piece 24 of the same pole as magnet piece 14" means "magnet piece 24 with the same poles as magnet piece 14 facing each other."

[0034] [Adhesive 34, Adhesive 38] 2(A) and 2(B), adhesive 34 is applied to adhesive surface 20 and adhesive surface 30. In this embodiment, "application" refers to spreading a gel-like material or the like on the target area. Note that, for example, a cyanoacrylate-based low-viscosity adhesive is used as adhesive 34.

[0035] The adhesive 38 is applied to the chamfered portions 23 and 33, surrounding the adhesive 34 applied between the bonding surfaces 20 and 30 from the outside. In other words, the adhesive 38 is applied across the chamfered portions 23 and 33 to prevent the adhesive 34 applied across the bonding surfaces 20 and 30 from coming into contact with the outside air. The hardness of the adhesive 38 is lower than that of the adhesive 34. In other words, the adhesive 38 is more easily deformed than the adhesive 34. In other words, even if the relative positions of the magnet pieces 14 and 24 change due to temperature changes or the like, the adhesive 38 deforms accordingly. This allows the adhesive 38 to function as a sealant that prevents the adhesive 34 from coming into contact with the outside air. For example, a high-viscosity cyanoacrylate adhesive is used as the adhesive 38.

[0036] (Magnet part 100) As shown in FIG. 4, the magnet section 100 includes a magnet body 10 and a pair of magnet bodies 40 arranged to sandwich the magnet body 10 in the circumferential direction when viewed from one direction.

[0037] As shown in Fig. 5, magnet body 40 includes magnet piece 44 and magnet piece 54. The following description will focus mainly on the differences between magnet body 40 and magnet body 10. Magnet piece 44 is an example of one magnet piece, and magnet piece 54 is an example of the other magnet piece.

[0038] The magnet piece 44 has a shape similar to that of the magnet piece 14 of the magnet body 10 (see FIG. 3), and the magnet piece 54 has a shape similar to that of the magnet piece 24 (see FIG. 3).

[0039] The magnet piece 44 is formed with an outer peripheral surface 46a, an inner peripheral surface 46b, a pair of end faces 48, an adhesive surface 50, side surfaces 52, and a chamfered portion 53. The adhesive surface 50 is an example of one adhesive surface. The magnet piece 54 is formed with an outer peripheral surface 56a, an inner peripheral surface 56b, a pair of end faces 58, an adhesive surface 60, side surfaces 62, and a chamfered portion 63. The adhesive surface 60 is an example of another adhesive surface, and the chamfered portion 63 is an example of another chamfered portion.

[0040] Furthermore, as shown in FIGS. 6(A) and 6(B), adhesive 64 is applied between bonding surfaces 50 and 60 to bond magnet pieces 44 and 54, and adhesive 68 is applied between chamfered portions 53 and 63, surrounding adhesive 64. In other words, adhesive 68 is applied across chamfered portions 53 and 63 to prevent adhesive 64 applied across bonding surfaces 50 and 60 from coming into contact with the outside air. The same adhesive as adhesive 34 is used for adhesive 64, and the same adhesive as adhesive 38 is used for adhesive 68. Adhesive 68 is an example of another adhesive. Note that FIG. 6(A) is a cross-sectional view of magnet body 40 shown in FIG. 5, cut along a plane perpendicular to one direction (direction D in the figure). FIG. 6(B) is a cross-sectional view of magnet body 40 shown in FIG. 5, cut along a plane perpendicular to bonding surfaces 50 and 60.

[0041] 5, the magnetic field orientation direction from the south pole to the north pole inside magnet piece 44 (the direction of arrow G3 in the figure) is a direction from the portion of outer peripheral surface 46a on the bonding surface 50 side to the portion of inner peripheral surface 46b on the side surface 52 side when viewed from one direction. In other words, when viewed from one direction, magnet piece 44 has an south pole (S3 in the figure) on the radially outer side and an north pole (N3 in the figure) on the radially inner side, and the boundary surface between the north pole and the south pole (dotted line in the figure) is perpendicular to magnetic field orientation direction G3 from the south pole to the north pole.

[0042] Furthermore, as shown in FIG. 5, the magnetic field orientation direction (indicated by arrow G4 in the figure) from the south pole to the north pole inside the magnet piece 54 is symmetrical to the magnetic field orientation direction G3 of the magnet piece 44 across the adhesive 64. In other words, the magnetic field orientation direction G4 inside the magnet piece 54 is a direction from the adhesive surface 60 side of the outer peripheral surface 56a to the side surface 62 side of the inner peripheral surface 56b when viewed from one direction. In other words, when viewed from one direction, the magnet piece 54 has an south pole (S4 in the figure) on the radially outer side and an north pole (N4 in the figure) on the radially inner side, and the boundary between the north and south poles (dotted line in the figure) is perpendicular to the magnetic field orientation direction G4 from the south pole to the north pole. In this way, the magnet pieces 44 and 54 have the same poles facing each other across the adhesive 64 (N3 and N4 facing each other, and S3 and S4 facing each other).

[0043] 4, the magnet section 100 is formed by a pair of magnet bodies 40 sandwiching the magnet body 10 from the circumferential direction (both sides) of the magnet body 10. The magnet section 100 is fan-shaped with a central angle of 180 degrees or less.

[0044] Furthermore, adhesive 78 is applied between side surface 22 of magnet piece 14 in magnet body 10 and side surface 62 of magnet piece 54 in magnet body 40 on the left side in the figure. The same adhesive as adhesive 38 is used for adhesive 78. Furthermore, adhesive 88 is applied between side surface 32 of magnet piece 24 in magnet body 10 and side surface 52 of magnet piece 44 in magnet body 40 on the right side in the figure. The same adhesive as adhesive 38 is used for adhesive 88. In this manner, magnet body 10 and the pair of magnet bodies 40 are bonded together. Note that in magnet section 100, no other adhesive is applied to surround the adhesive 78 that bonds magnet body 10 and magnet body 40 on the left side in the figure. This is because a magnetic attraction force acts between magnet body 10 and magnet body 40 on the left side in the figure, so even if adhesive 78 deteriorates, separation between magnet body 10 and magnet body 40 on the left side in the figure is unlikely to progress. Similarly, in magnet section 100, no other adhesive is applied to surround the outside of adhesive 88 that bonds magnet body 10 to magnet body 40 on the right side of the figure. This is also because a magnetic attractive force acts between magnet body 10 and magnet body 40 on the right side of the figure, so even if adhesive 88 deteriorates, separation between magnet body 10 and magnet body 40 on the right side of the figure is unlikely to progress.

[0045] In the circumferential direction of the magnet section 100, the N-pole magnet body 10 is arranged in the center, and the S-pole magnet bodies 40 are arranged on both ends. Specifically, with regard to the magnetic poles on the outer circumferential surface side of the magnet section 100, the central magnet body 10 is the N-pole, and the magnet bodies 40 on both ends are the S-pole.

[0046] (Magnetic body manufacturing method) Next, a description will be given of a manufacturing method for the magnet body 10. The magnet body 40 is also manufactured by the same manufacturing method.

[0047] First, as shown in FIG. 1, magnet pieces 14 extending in one direction and magnet pieces 24 extending in one direction are prepared (preparation step).

[0048] 7(A), the adhesive surface 20 of the magnet piece 14 and the adhesive surface 30 of the magnet piece 24 are brought into contact with each other so that the same poles face each other. Specifically, the adhesive surfaces 20 and 30 are brought into contact with each other so that the north pole (N1 in the figure) of the magnet piece 14 and the north pole (N2 in the figure) of the magnet piece 24 face each other with the adhesive surfaces 20 and 30 in between, and so that the south pole (S1 in the figure) of the magnet piece 14 and the south pole (S2 in the figure) of the magnet piece 24 face each other with the adhesive surfaces 20 and 30 in between.

[0049] Furthermore, the magnet pieces 14 and 24 are positioned on their inner peripheral surfaces. Specifically, a jig 120 is used, on which arcuate surfaces 120a are formed along the inner peripheral surfaces 16b and 26b of the magnet pieces 14 and 24. The inner peripheral surfaces 16b and 26b of the magnet pieces 14 and 24 are pressed against the arcuate surfaces 120a of the jig 120, thereby positioning the magnet pieces 14 and 24 on their inner peripheral surfaces (positioning step).

[0050] Furthermore, with the magnet pieces 14 and 24 positioned, adhesive 34 is injected between the bonding surfaces 20 and 30 from the outer circumferential surface side (see arrow R in FIG. 7(B)). As a result, adhesive 34 is applied to the bonding surfaces 20 and 30 (bonding process).

[0051] Specifically, due to surface tension, adhesive 34 penetrates between bonding surfaces 20 and 30 from the outer peripheral surface side. For this reason, as shown in Fig. 8, adhesive 34 is sufficiently applied to the bonding surfaces 20 and 30 on the outer peripheral surface 16a, 26a side, while there are portions of bonding surfaces 20 and 30 on the inner peripheral surface 16b, 26b side where adhesive 34 is not applied. The reason for providing portions of bonding surfaces 20 and 30 on the inner peripheral surface 16b, 26b side where adhesive 34 is not applied is to prevent inner peripheral surface 16b of magnet piece 14 and inner peripheral surface 26b of magnet piece 24 from being bonded to arcuate surface 120a of jig 120 by adhesive 34. In other words, if a large amount of adhesive 34 is allowed to seep into the gap between bonding surfaces 20 and 30 from the outer peripheral surface side so as to ensure that there are no areas on the bonding surfaces 20 and 30 on the inner peripheral surfaces 16b and 26b side where adhesive 34 is not applied, the adhesive 34 that overflows from bonding surfaces 20 and 30 will penetrate between the inner peripheral surfaces 16b and 26b and the arcuate surface 120a of the jig 120, bonding the inner peripheral surfaces 16b and 26b to the arcuate surface 120a. If this occurs, the production efficiency of the magnet body 10 will be reduced, which is an inconvenience.

[0052] In this embodiment, the magnetic field orientation direction G1 inside the magnet piece 14 and the magnetic field orientation direction G2 inside the magnet piece 24 collide (face each other) at the N poles on the outer peripheral surface side. In other words, a stronger repulsive force (fleeing force) acts between the N poles on the outer peripheral surface side than between the S poles on the inner peripheral surface side. Furthermore, the adhesive 34 is applied more thoroughly to the bonding surfaces 20, 30 on the outer peripheral surface 16a, 26a side, where the repulsive force is stronger, than to the bonding surfaces 20, 30 on the inner peripheral surface 16b, 26b side, where the repulsive force is weaker. In other words, the adhesive 34 is less likely to be applied to the bonding surfaces 20, 30 on the outer peripheral surface 16a, 26a side, where the repulsive force is stronger, compared to the bonding surfaces 20, 30 on the inner peripheral surface 16b, 26b side, where the repulsive force is weaker.

[0053] Next, the magnet pieces 14 and 24 bonded with the adhesive 34 are separated from the jig 120, and adhesive is applied to the chamfered portions 23 and 33 so as to surround the adhesive 34, as shown in Fig. 2. This causes the adhesive 34 to be sealed with the adhesive 38 (sealing process).

[0054] (others) Next, a developing device including the magnet portion 100 as a component will be described.

[0055] The developing device 130 is used in a xerographic image forming apparatus, and as shown in Fig. 9, includes a developing roll 132 disposed opposite an image carrier 160. The developing device 130 also includes an agitating and conveying auger 140 disposed below the developing roll 132 and conveying the developer G supplied to the developing roll 132, and an agitating and conveying auger 142 disposed adjacent to the agitating and conveying auger 140. The developing device 130 also includes a housing 144 that accommodates the agitating and conveying auger 140, the agitating and conveying auger 142, and the developer G therein.

[0056] The developing roll 132 includes a magnetic roll 134 and a cylindrical sleeve 136 that accommodates the magnetic roll 134 and rotates in the circumferential direction of the magnetic roll 134 .

[0057] 10, the magnetic roll 134 comprises a cylindrical shaft portion 152, a magnet portion 100 bonded to the outer peripheral surface of the shaft portion 152, and a plurality of magnet pieces 154 with a fan-shaped cross section. An adhesive 38 is applied to the inner peripheral surfaces of the magnet portion 100 and the plurality of magnet pieces 154, and to the outer peripheral surface of the shaft portion 152.

[0058] (summary) As explained above, in magnet body 10, adhesive 34, which bonds magnet piece 14 and magnet piece 24 of the same polarity as magnet piece 14, is surrounded by adhesive 38. This prevents magnet piece 14 and magnet piece 24 from peeling apart, compared to when a pair of magnet pieces of the same polarity are bonded with a single type of adhesive and the adhesive is exposed to the outside air.

[0059] Furthermore, the magnet body 10 is composed of a pair of magnet pieces 14, 24 of the same polarity. This results in a single magnet body 10 with a stronger magnetic force than when the magnet body is composed of a single magnet piece.

[0060] Furthermore, in the magnetic body 10, the adhesive 34 is surrounded by the adhesive 38, which has a lower hardness than the adhesive 34. Therefore, compared to when the adhesive 34 is surrounded and sealed using tape (for example, flexible adhesive tape) attached so as to straddle the magnet piece 14 and the magnet piece 24, the occurrence of portions where the adhesive 34 is not sealed by the adhesive 38 is suppressed.

[0061] Furthermore, in the magnetic body 10, the adhesive 34 is sealed with the adhesive 38. Therefore, the adhesive strength between the magnetic pieces 14 and 24 is improved compared to when sealing is performed with, for example, a gel sealant that does not harden over time.

[0062] Furthermore, in the magnetic body 10, a chamfered portion 23 to which adhesive 38 is applied is formed on the outer periphery of the bonding surface 20. This reduces the occurrence of portions where the adhesive 34 is not sealed by the adhesive 38, compared to when adhesive 38 is applied between the bonding surfaces 20, 38 to seal the adhesive 34.

[0063] Furthermore, in the magnetic body 10, a chamfered portion 23 is formed around the entire outer periphery of the bonding surface 20. Therefore, compared to when a chamfered portion is formed only partially, the occurrence of portions where the adhesive 34 is not sealed by the adhesive 38 is suppressed.

[0064] Furthermore, in magnet body 10, magnet piece 14 and magnet piece 24 are symmetrical with respect to adhesive 34. Therefore, compared to when a chamfered portion is formed on only one of the magnet pieces, the occurrence of portions where adhesive 34 is not sealed by adhesive 38 is suppressed.

[0065] In addition, in the magnet section 100, the magnet body 40, which is made up of a pair of magnet pieces 44, 54 and has a magnetic pole on its outer periphery that is an S pole, is disposed on each end of the magnet body 10, which is made up of a pair of magnet pieces 14, 24 and has a magnetic pole on its outer periphery that is an N pole. Therefore, the magnetic flux density of the central N pole is greater than when the magnet body, which is made up of a single magnet piece and has a magnetic pole on its outer periphery that is an S pole, is disposed on each end of the magnet body, which is made up of a single magnet piece and has a magnetic pole on its outer periphery that is an N pole.

[0066] Furthermore, in the manufacturing method of the magnet body, the magnet pieces 14 and 24 are less likely to separate from each other than when manufacturing is completed with the bonding step.

[0067] Furthermore, in the manufacturing method of the magnet body, the occurrence of portions where the adhesive 34 is not applied is suppressed on the bonding surfaces 20, 30 on the outer peripheral surfaces 16a, 26a side where the repulsion is strong, compared to the bonding surfaces 20, 30 on the inner peripheral surfaces 16b, 26b side where the repulsion is weak. In other words, separation of the magnet pieces 14 and 24 is suppressed compared to the case where portions where the adhesive 34 is not applied are generated on the bonding surfaces 20, 30 on the outer peripheral surfaces 16a, 26a side where the repulsion is strong.

[0068] Although the present invention has been described in detail with reference to a specific embodiment, it will be apparent to those skilled in the art that the present invention is not limited to such an embodiment and that various other embodiments are possible within the scope of the present invention. For example, in the above embodiment, the adhesive 34 is sealed with the adhesive 38, but the adhesive 34 may also be sealed with tape. However, in this case, the effect achieved by sealing with the adhesive 38 will not be achieved.

[0069] In the above embodiment, the adhesive 34 is sealed with the adhesive 38, but the adhesive 34 may also be sealed with a sealant. However, in this case, the effect achieved by sealing with the adhesive 38 is not achieved. In this embodiment, the sealant is a gel-like material that does not harden over time.

[0070] In the above embodiment, the chamfered portions 23, 33 are formed on the entire outer periphery of the bonding surfaces 20, 30, but the chamfered portions may be formed only on a part of the outer periphery. However, in this case, the effect achieved by forming the chamfered portions 23, 33 on the entire outer periphery is not achieved.

[0071] Furthermore, in the above embodiment, the action of the magnet body 10 has been described in detail, but the magnet body 40 also exerts the same action as the magnet body 10.

[0072] In addition, in the above embodiment, the adhesive 64 and the adhesive 34 are similar adhesives, and the adhesive 68 and the adhesive 38 are similar adhesives, but the adhesive 64 and the adhesive 34 may be the same adhesive, and the adhesive 68 and the adhesive 38 may be the same adhesive. In addition, in the above embodiment, the adhesive 78 and the adhesive 38 are similar adhesives, and the adhesive 88 and the adhesive 38 are similar adhesives, but the adhesive 78 and the adhesive 38 may be the same adhesive, and the adhesive 88 and the adhesive 38 may be the same adhesive.

[0073] Furthermore, in the above embodiment, magnet section 100 is shown having magnet body 10 and a pair of magnet bodies 40 arranged to sandwich magnet body 10 in the circumferential direction when viewed from one direction ( FIG. 4 ). However, magnet section 100 may also be composed of magnet body 40 and a pair of magnet bodies 10 arranged to sandwich magnet body 40 in the circumferential direction when viewed from one direction. That is, magnet section 100 may have magnet body 10 composed of a pair of magnet pieces 14, 24 and having a north pole on its outer periphery, and magnet body 10 composed of a pair of magnet pieces 44, 54 and having a south pole on its outer periphery, respectively, arranged at both ends of magnet body 40. In this case, the magnetic flux density of the central south pole is smaller than when magnet bodies composed of a single magnet piece and having a north pole on its outer periphery are arranged at both ends of magnet body 40 composed of a single magnet piece and having a south pole on its outer periphery. [Explanation of symbols]

[0074] 10. Magnet body 14 Magnet piece (an example of one magnet piece) 20 Adhesive surface (example of one adhesive surface) 23 Chamfered part 24 Magnet piece (an example of another magnet piece) 30 Adhesive surface (an example of another adhesive surface) 33 Chamfered portion (an example of another chamfered portion) 34 Adhesive 38 Adhesives (examples of other adhesives, sealants, and sealing parts) 40 Magnet body 44 Magnet piece (an example of one magnet piece) 50 Adhesive surface (example of one adhesive surface) 53 Chamfered part 54 Magnet piece (an example of another magnet piece) 60 Adhesive surface (an example of another adhesive surface) 63 Chamfered part (an example of another chamfered part) 100 Magnet section

Claims

[Claim 1] a step of preparing one magnet piece having a sector-shaped cross section, extending in one direction, and having one adhesive surface formed on a side surface thereof, and another magnet piece having a sector-shaped cross section, extending in one direction, and having another adhesive surface formed on a side surface thereof; a step of bringing the first adhesive surface and the second adhesive surface into contact with each other so that the same poles face each other and a stronger repulsive force acts on the outer peripheral surface side than on the inner peripheral surface side, positioning the first magnet piece and the second magnet piece using a jig with an arc-shaped surface on the inner peripheral surface side, and injecting adhesive between the first adhesive surface and the second adhesive surface from the outer peripheral surface side to bond the first magnet piece and the second magnet piece so that there is a portion on the inner peripheral surface side where the adhesive is not applied; a step of separating the magnet pieces from the jig and applying a sealant to the one magnet piece and the other magnet piece so as to surround the adhesive, thereby sealing the adhesive; A method for manufacturing a magnet body comprising:

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