JP2004096961A - Annular magnet and rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotor comprising annular magnets that can improve motor characteristics by preventing the occurrence of differences in magnetic force between magnetic poles. <P>SOLUTION: A cylindrical molded unit 13 is formed by combining annularly a prescribed number of circular premolded units 14 that are oriented radially, and by fixing their joints 15 to integrate the molded units 14. An annular magnet 12 is structured by being fixed and integrated by stacking the cylindrical molded units 13 in a prescribed number of steps in the axial direction, and by displacing in the circumferential direction the joints 15 of the premolded units 14 of the cylindrical modeled units 13 neighboring in the axial direction. The rotor is obtained by fitting the annular magnets 12 to the outside circumferential part of a rotating shaft 11 and by fixing and integrating them with the shaft. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ring-type magnet used for a rotor of a motor or the like, and more particularly to a structure for obtaining a long magnet in the axial direction.
[0002]
[Prior art]
In general, when magnetically forming a radial anisotropic ring magnet often used in small motors, when forming a cylindrical magnet that is long in the axial direction, sufficient magnetic field strength cannot be obtained, and the orientation rate of the magnetic powder is low. There is a problem in that the high magnetic characteristics cannot be obtained.
In order to solve this problem, for example, in Japanese Patent Application Laid-Open No. 7-161512, an arc-shaped preform 1 that is oriented in the radial direction and relatively easy to mold as shown in FIG. It is proposed that an anisotropic ring-type magnet is obtained by combining the number, butting the joints 2 and fixing them in a ring shape and sintering them.
[0003]
[Problems to be solved by the invention]
In the conventional anisotropic ring magnet, the arc-shaped preform 1 oriented in the radial direction as described above is magnetically oriented, combined with a predetermined number, and the joints 2 are abutted and fixed in a ring shape. In this case, the magnetic powder is discontinuously oriented at the position of the joint 2 where the pre-formed body 1 has high magnetic properties. As a result, the magnetic properties deteriorate locally. Therefore, the imbalance between the pole position after magnetization and the fixing position of the preform 1 has an adverse effect on the motor characteristics. For example, as shown in FIG. 11, when a ring shape formed by combining four preforms 1 is magnetized to 8 poles, a place where there is a joint 2 between the N pole and the S pole, and the joint 2 is Since there is no portion, there is a problem that a magnetic force difference is generated between the magnetic pole having the joint 2 between the poles and the magnetic pole without the joint.
[0004]
The present invention has been made to solve the above-described problems, and provides a ring magnet and a rotor capable of improving the motor characteristics by preventing the difference in magnetic force between the magnetic poles. It is intended to do.
[0005]
[Means for Solving the Problems]
According to a first aspect of the present invention, a ring-shaped magnet is formed by combining a plurality of arc-shaped preforms with radial orientation in an annular shape to form a cylindrical molded body, and a plurality of cylindrical molded bodies in the axial direction. The stacks are stacked and fixed together by shifting the joints of the arc-shaped preforms between the cylindrical molded bodies adjacent to each other in the axial direction in the circumferential direction.
[0006]
In the ring magnet according to claim 2 of the present invention, the number of arc-shaped preforms is A, the number of stacked stages of cylindrical shaped bodies is B, and the number of magnetized poles is C. In this case, A and B are set to a number in which A × B is an integral multiple of C, and the cylindrical shaped body is set to the larger of 360 ° / (A × B) and 360 ° / C. They are stacked one after the other by shifting the value angle.
[0007]
A ring magnet according to a third aspect of the present invention is the ring-type magnet according to the first or second aspect, wherein the axial length is the same at both ends in the circumferential direction on both axial end surfaces of the arc-shaped preform. In addition, a concave portion and a convex portion whose predetermined position coincides with the center of the magnetic pole to be magnetized are formed.
[0008]
According to a fourth aspect of the present invention, in the ring magnet according to any one of the first to third aspects, a high electrical resistance layer is interposed between the adjacent arc-shaped preforms and between the cylindrical molded bodies. Is.
[0009]
According to a fifth aspect of the present invention, a rotor includes the ring magnet according to any one of the first to fourth aspects at an outer peripheral portion of a rotating shaft.
[0010]
According to a sixth aspect of the present invention, in the rotor according to the fifth aspect, the ring-shaped magnet has a preliminarily sintered or fired arc-shaped preform that is fixedly disposed around the rotation shaft with an adhesive. Is formed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
1 is a perspective view showing a configuration of a rotor according to Embodiment 1 of the present invention, FIG. 2 is a perspective view showing a configuration of a ring-type magnet in FIG. 1, and FIG. 3 is adjacent to a cylindrical molded body in FIG. FIG. 4 is a developed view showing the positional relationship between each other. FIG. 4 shows the positions of the magnetized N and S poles of the first and third cylindrical shaped bodies of the ring magnet in FIG. FIG. 5 is a plan view showing the relationship between the positions of joints in the molded body. FIG. 5 shows the positions of the magnetized N and S poles of the second and fourth cylindrical molded bodies in FIG. It is a top view which shows the relationship of the position of the joint of a preforming body.
[0012]
In the figure, 11 is a rotating shaft of the rotor, 12 is a ring magnet formed by stacking a plurality of stages (four stages in the figure) of the cylindrical molded body 13 as shown in FIG. They are fixedly integrated with the outer periphery of the rotating shaft 11. Then, the cylindrical shaped body 13 is formed by combining a predetermined number (four in the drawing) of the arcuate preforms 14 oriented in the radial direction in an annular shape, and the joint 15 of the arcuate preforms 14 is The cylindrical formed bodies 13 adjacent to each other are arranged so as to be shifted by 45 ° in the circumferential direction, and as shown in FIG. Are formed in total.
[0013]
As described above, according to the first embodiment, the plurality of arc-shaped preforms 14 subjected to radial orientation are combined in an annular shape to form the cylindrical molded body 13, and the cylindrical molded body 13 is Since the ring-type magnet 12 is configured by stacking and fixing in a plurality of stages in the axial direction, the length of the arc-shaped preform 14 can be divided in the axial direction to make it shorter. It becomes easy and productivity can be improved.
[0014]
Further, the cylindrical molded body 13 is arranged so that the positions of the joints 15 of the adjacent arc-shaped preforms 14 are shifted by 45 ° as shown in FIG. As can be seen from FIG. 5, the joints 15 can be evenly arranged between any poles, so that it is possible to prevent the difference in magnetic force between the magnetic poles and improve the motor characteristics.
[0015]
In the configuration described above, the four arc-shaped preforms 14 are combined in an annular shape to form the cylindrical molded body 13, and the cylindrical molded bodies 13 are arranged adjacent to each other in the arc-shaped preform 14. The joints 15 are arranged so that the positions of the joints 15 are shifted by 45 °, and the joints 15 existing between the poles are evenly arranged by stacking four stages in the axial direction. Rather, if the number of arc-shaped preforms 14 is A, the number of stacked stages of cylindrical molded bodies 13 is B, and the number of poles to be magnetized is C, then A and B are integers of A × B is C If the number is doubled, the cylindrical molded body 13 is sequentially stacked while being shifted by an angle of the larger value of 360 ° / (A × B) and 360 ° / C. It is possible to demonstrate the same effect as above Yes.
[0016]
Embodiment 2. FIG.
6 is a perspective view showing a configuration of a rotor according to Embodiment 2 of the present invention, and FIG. 7 is a perspective view showing a configuration of a ring-type magnet in FIG.
In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Reference numeral 16 denotes a ring-type magnet formed by stacking a plurality of stages (four stages in the figure) of the cylindrical molded body 17 as shown in FIG. Are fixed and integrated.
[0017]
The cylindrical shaped body 17 is formed by combining a predetermined number (four in the figure) of the arc-shaped preforms 14 oriented in the radial direction in an annular shape, and the joints of the arc-shaped preforms 14 are connected to each other. The adjacent cylindrical molded bodies 17 are arranged so as to be shifted from each other by 45 ° in the circumferential direction, and the joints between the respective arc-shaped preforms 14 and the cylindrical molded bodies 17 are provided with high heights such as titanic acid ceramics. A high voltage resistance layer 18 is formed by filling a member having a voltage resistance.
[0018]
As described above, according to the second embodiment, each arc-shaped preform 14 and cylindrical molded body 17 is filled with the member having high voltage resistance to form the high electrical resistance layer 18. Therefore, the eddy current generated in the ring magnet 16 can be suppressed and the motor characteristics can be improved.
[0019]
In the first and second embodiments, the rotors are configured by fitting the sintered or fired ring magnets 12 and 16 to the outer periphery of the rotating shaft 11, respectively. The arc-shaped preform 14 that has been bonded or fired is fixed with, for example, an adhesive containing 0.05 mm diameter resin, ceramics, or glass beads to form the ring magnets 12 and 16, respectively, so as to constitute a rotor. In this case, since the ring-shaped magnets 12 and 16 are formed using the arc-shaped preform 14 sintered in advance, the ring-shaped magnets 12 and 16 are formed and then sintered. In this case, it is possible to avoid the occurrence of a sintering failure due to the presence of layers having different compositions between the arc-shaped preforms 14 and to improve productivity.
[0020]
Embodiment 3 FIG.
FIG. 8 is a developed view showing the configuration of the main part of the ring magnet according to the third embodiment of the present invention, and FIGS. 9A and 9B are the main parts of the ring magnet according to the third embodiment of the present invention. FIG. 9 is a development view showing a configuration different from FIG.
In the figure, 19 is oriented in the radial direction, and its predetermined position (vertex in the figure) is magnetized so that the axial length is the same at any position in the circumferential direction on both end faces in the axial direction. An arc-shaped preform 20 having a concave portion 20 and a convex portion 21 that coincide with the center of the magnetic pole, and 22 is formed by combining a predetermined number (four in the figure) of the arc-shaped preform 19 in an annular shape. A ring-shaped magnet 23 is formed by stacking a plurality of stages so that the joints 21 of the arc-shaped preform 19 are shifted by 45 ° from each other.
[0021]
As described above, according to the third embodiment, the axial length of each end of the arc-shaped preform 19 is the same at any circumferential position, and the predetermined position is magnetized. Since the concave portion 20 and the convex portion 21 that coincide with the center of the magnetic pole to be formed are formed, positioning can be performed when only the concave portion 20 and the convex portion 21 are combined, so that productivity can be improved. become.
In the above configuration, the shape of the concave and convex portions 20 and 21 is an arc shape, but is not limited to this, and as shown in FIG. 9A, the concave and convex portions of the arc-shaped preform 24 are formed. Even if 25 and 26 are formed in a triangular shape, and the concave and convex portions 28 and 29 of the arc-shaped preform 27 are formed in a rectangular shape as shown in FIG. 9B, the same effect as described above can be obtained. it can.
[0022]
【The invention's effect】
As described above, according to the first aspect of the present invention, a plurality of arc-shaped preforms subjected to radial orientation are combined in an annular shape to form a cylindrical molded body, and the cylindrical molded body is axially aligned. Since the joints of the cylindrical preforms adjacent to each other in the axial direction are shifted and fixed in the circumferential direction, the magnetic force difference between the magnetic poles is prevented. It is possible to provide a ring magnet that can improve motor characteristics.
[0023]
According to claim 2 of the present invention, in claim 1, when the number of arc-shaped preforms is A, the number of stacked stages of cylindrical shaped bodies is B, and the number of magnetized poles is C, A , B is a number such that A × B is an integral multiple of C, and the angle of the larger value between the 360 ° / (A × B) value and the 360 ° / C value of the cylindrical molded body Since they are sequentially stacked while being shifted from each other, it is possible to provide a ring-type magnet capable of preventing the difference in magnetic force between the magnetic poles and improving the motor characteristics.
[0024]
Further, according to claim 3 of the present invention, in claim 1 or 2, the axial length is the same at both ends in the circumferential direction on the both axial end surfaces of the arc-shaped preform. Since the concave portion and the convex portion that coincide with the center of the magnetic pole to be magnetized at a predetermined position are formed, it is possible to provide a ring magnet that can be easily positioned and improved in productivity.
[0025]
According to a fourth aspect of the present invention, in any one of the first to third aspects, since the high electrical resistance layer is interposed between the adjacent arc-shaped preforms and the cylindrical molded body, It is possible to provide a ring magnet that can suppress current and improve motor characteristics.
[0026]
According to claim 5 of the present invention, since the ring magnet according to any one of claims 1 to 4 is provided on the outer peripheral portion of the rotating shaft, a rotor capable of improving motor characteristics is provided. Can be provided.
[0027]
According to a sixth aspect of the present invention, in the fifth aspect, the ring-type magnet is formed by adhering a pre-sintered or fired arc-shaped preform to the periphery of the rotating shaft with an adhesive. Therefore, a rotor capable of improving productivity can be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a rotor according to Embodiment 1 of the present invention.
2 is a perspective view showing a configuration of a ring-type magnet in FIG. 1. FIG.
3 is a development view showing the positional relationship between adjacent cylindrical molded bodies in FIG. 2 in an expanded manner.
4 is a plan view showing the relationship between the positions of the magnetized N and S poles of the first and third cylindrical shaped bodies of the ring magnet in FIG. 2 and the joint position of the arc-shaped preform. FIG. FIG.
5 is a plane showing the relationship between the positions of the magnetized N and S poles of the second and fourth cylindrical shaped bodies of the ring magnet in FIG. 2 and the joint position of the arc-shaped preform. FIG. FIG.
FIG. 6 is a perspective view showing a configuration of a rotor according to Embodiment 2 of the present invention.
7 is a perspective view showing a configuration of a ring-type magnet in FIG. 6. FIG.
FIG. 8 is a development view showing a configuration of a main part of a ring magnet according to Embodiment 3 of the present invention.
FIG. 9 is a developed view showing a configuration different from FIG. 8 of the main part of the ring-type magnet according to Embodiment 3 of the present invention.
FIG. 10 is a perspective view showing a part of a configuration of a conventional anisotropic ring magnet.
11 is a plan view showing the relationship between the joint position of the anisotropic ring-shaped magnet preform in FIG. 10 and the positions of the magnetized N and S poles.
[Explanation of symbols]
11 Rotating shaft, 12, 16, 23 Ring magnet,
13, 17, 22 cylindrical shaped body,
14, 19, 24, 27 Arc-shaped preform, 15 joints,
18 High electrical resistance layer, 20, 25, 28 Concave part, 21, 26, 29 Convex part.

Claims (6)

A plurality of arc-shaped preforms with radial orientation are combined in an annular shape to form a cylindrical molded body, and the cylindrical molded bodies are stacked in a plurality of stages in the axial direction, and the cylinders adjacent to each other in the axial direction A ring-type magnet characterized in that the joints of the arc-shaped preforms between the shaped compacts are fixedly integrated in a circumferential direction. Assuming that the number of the arc-shaped preforms is A, the number of stacked stages of the cylindrical shaped bodies is B, and the number of poles to be magnetized is C, A × B is an integral multiple of C. The cylindrical molded bodies are sequentially stacked while being shifted by an angle of the larger one of the value of 360 ° / (A × B) and the value of 360 ° / C. The ring magnet according to claim 1. Concave and convex portions on both end surfaces in the axial direction of the arc-shaped preform so that the axial length is the same at any circumferential position and the predetermined position coincides with the center of the magnetic pole to be magnetized The ring magnet according to claim 1, wherein the ring magnet is formed. The ring magnet according to any one of claims 1 to 3, wherein a high electrical resistance layer is interposed between the arcuate preforms adjacent to each other and between the cylindrical molded bodies. 5. A rotor comprising the ring-type magnet according to claim 1 on an outer peripheral portion of a rotating shaft. 6. The rotor according to claim 5, wherein the ring-shaped magnet is formed by adhering and arranging a pre-sintered or fired arcuate preform in the periphery of the rotating shaft with an adhesive. .

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