Permanent magnets used in linear rotary actuators

Abstract

The permanent magnet (100) used in the linear rotation actuator has a first pole group having one or more equally spaced first poles (1) in the circumferential direction on the opposing surfaces, which generate magnetic flux from the outer diameter side to the inner diameter side in the radial direction, and a second pole group having one or more equally spaced second poles (2) in the circumferential direction, which generate magnetic flux from the inner diameter side to the outer diameter side in the radial direction. The first pole group is arranged at a predetermined distance axially from the second pole group and at a position circumferentially shifted by 180 electrical degrees. The magnet region between the magnetic pole centers of the N pole or S pole appearing on the opposing surfaces of the first pole (1) and the adjacent second pole (2) is magnetized so that the magnetic flux has at least a circumferential component.

Description

[Technical Field]

[0001] The present disclosure relates to permanent magnets used in linear rotary actuators. [Background technology]

[0002] Conventionally, actuators that can be driven in a linear or rotational direction have been known. The actuators have permanent magnets attached to their armature or mover. For example, the permanent magnets disclosed in Patent Document 1 are magnetized so that south and north poles are alternately arranged, and are arranged at a predetermined distance from the stator of a rotating electric machine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-32356 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in fields such as electronic component mounting equipment and semiconductor manufacturing equipment, an actuator capable of driving in both linear and rotational directions is sometimes required. However, it is difficult to obtain a magnetic flux capable of driving in both linear and rotational directions using a single permanent magnet. For this reason, it has been difficult to realize an actuator that can drive in both linear and rotational directions using a single permanent magnet, a so-called two-axis integrated type. Therefore, the actuator requires a well-known linear drive mechanism and a rotational drive mechanism, such as that disclosed in Patent Document 1. Because the actuator is a two-axis separate type, there is a risk that the machine base supporting these drive mechanisms will become large.

[0005] The present disclosure has been made in view of the above, and has an object to provide a permanent magnet for use in a direct acting rotation actuator that can be driven in both the direct acting direction and the rotational direction. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the permanent magnet used in the direct acting rotation actuator according to the present disclosure is a cylindrical permanent magnet used in the direct acting rotation actuator, having a plurality of magnetic poles on a surface facing an armature or a mover that constitutes the direct acting rotation actuator, A cylindrical magnet is magnetized to have multiple magnetic poles, The rotor has a first pole group having one or more equally spaced first poles in the circumferential direction on the opposing surfaces, which generate magnetic flux from the outer diameter side to the inner diameter side in the radial direction, and a second pole group having one or more equally spaced second poles in the circumferential direction, which generate magnetic flux from the inner diameter side to the outer diameter side in the radial direction. The first pole group is positioned a predetermined distance axially from the second pole group and circumferentially shifted in phase by 180 electrical degrees. The magnet region between the centers of the N or S poles that appear on the opposing surfaces of the first pole and the adjacent second pole is magnetized so that the magnetic flux flows from the outer diameter side to the inner diameter side and then out to the outer diameter side. [Effects of the Invention]

[0007] The permanent magnet used in the linear rotation actuator according to the present disclosure has the advantage that it can be driven in both the linear direction and the rotation direction. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a permanent magnet used in a linear acting rotation actuator according to a first embodiment; [Figure 2] An explanatory diagram showing the orientation of magnetic flux when viewing a cross section of a permanent magnet taken along dashed line X in Figure 1. [Figure 3] An explanatory diagram showing the arrangement of magnetic poles required to obtain magnetic flux that can drive the motor in both the linear and rotational directions. [Figure 4] FIG. 10 is a perspective view showing a permanent magnet used in the direct acting rotation actuator according to the second embodiment; [Figure 5] FIG. 5 is an explanatory diagram showing the direction of magnetic flux in the V portion shown in FIG. 4 as viewed from the outer peripheral surface side in the radial direction of the permanent magnet. [Figure 6] FIG. 10 is a perspective view of a permanent magnet used in a direct acting rotation actuator according to a third embodiment, with a magnetic pole aspect ratio of 1:1; [Figure 7] FIG. 10 is a perspective view of a permanent magnet used in a direct acting rotation actuator according to a third embodiment, the magnetic pole aspect ratio of which is 2:1; [Figure 8] FIG. 7 is a perspective view schematically illustrating an example of a direct acting rotation actuator having a permanent magnet shown in FIG. [Figure 9] FIG. 8 is a perspective view schematically illustrating an example of a direct acting rotation actuator having a permanent magnet shown in FIG. [Figure 10] Magnetic flux density contour diagram in the cross section of the direct acting rotary actuator shown in Figure 8 [Figure 11] Magnetic flux density contour diagram in the cross section of the direct acting rotary actuator shown in Figure 9 [Figure 12] FIG. 10 is a perspective view showing a permanent magnet used in the direct acting rotation actuator according to the fourth embodiment; [Figure 13] FIG. 13 is a perspective view showing a first modified example of a permanent magnet used in the linear acting rotation actuator according to the fourth embodiment; [Figure 14] A side view of the direction A shown in Figure 13 [Figure 15] FIG. 13 is a perspective view showing a second modified example of the permanent magnet used in the direct acting rotation actuator according to the fourth embodiment; [Figure 16] FIG. 10 is a perspective view showing a permanent magnet used in a direct acting rotation actuator according to a fifth embodiment; [Figure 17] FIG. 13 is a perspective view showing one small magnet that constitutes a permanent magnet in embodiment 5. [Figure 18] FIG. 13 is a perspective view showing the other small magnet that constitutes the permanent magnet in the fifth embodiment. [Figure 19] FIG. 13 is a perspective view showing a modified example of one small magnet that constitutes the permanent magnet in the fifth embodiment. [Figure 20] FIG. 13 is a perspective view showing a modified example of the other small magnet constituting the permanent magnet in the fifth embodiment. [Figure 21]FIG. 13 is a perspective view showing a permanent magnet used in a direct acting rotation actuator according to a sixth embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a permanent magnet used in a direct acting rotation actuator according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0010] Embodiment 1 FIG. 1 is a perspective view showing a permanent magnet used in a linear motion rotary actuator according to a first embodiment. The linear motion rotary actuator includes an armature (not shown), a mover (not shown) facing the armature, and a permanent magnet 100 shown in FIG. 1. As shown in FIG. 1, the permanent magnet 100 is cylindrical and has multiple magnetic poles on a surface facing the armature or the mover. The permanent magnet 100 is configured by magnetizing the magnet into multiple diamond shapes. Specifically, the permanent magnet 100 includes a first pole group having one or multiple equally spaced first poles 1 in the circumferential direction that generate magnetic flux from the outer diameter side to the inner diameter side in the radial direction, and a second pole group having one or multiple equally spaced second poles 2 in the circumferential direction that generate magnetic flux from the inner diameter side to the outer diameter side in the radial direction. Here, the first pole is defined as a south pole, and the second pole is defined as a north pole. The first pole group is arranged at a position spaced a predetermined distance in the axial direction from the second pole group and at a position shifted in phase by an electrical angle of 180 degrees in the circumferential direction.

[0011] FIG. 2 is an explanatory diagram showing the orientation of magnetic flux when viewing a cross section of a permanent magnet taken along dashed line X in FIG. 1. (A) to (C) of FIG. 2 each illustrate an example of a magnetic flux orientation pattern. The arrows shown in (A) to (C) of FIG. 2 indicate the orientation of magnetic flux. The star symbols in FIG. 2 indicate the centers of the magnetic poles. In FIG. 2, the outer diameter sides of the permanent magnet 100 are the opposing surfaces. As shown in FIG. 2, the magnet region between the centers of the N and S poles appearing on the magnet surface of the first pole 1 and the adjacent second pole 2 is magnetized so that the magnetic flux direction has at least a circumferential component. This allows the permanent magnet 100 to concentrate magnetic flux and improve maximum magnetic flux density, thereby increasing the torque and power generation of the rotating electric machine.

[0012] FIG. 3 is an explanatory diagram showing the magnetic pole arrangement required to obtain magnetic flux that can be driven in both the linear and rotational directions. The linear direction is the direction along the axial direction of the permanent magnet 100. The rotational direction is the direction along the circumferential direction of the permanent magnet 100. As shown in FIG. 3(A), to obtain magnetic flux that can be driven in the linear direction, magnetic poles that generate magnetic flux in opposite directions must be arranged alternately along the axial direction of the cylindrical shape. Also, as shown in FIG. 3(B), to obtain magnetic flux that can be driven in the rotational direction, magnetic poles that generate magnetic flux in opposite directions must be arranged alternately along the circumferential direction of the cylindrical shape. Therefore, a magnetic pole arrangement that combines (A) and (B), as shown in FIG. 3(C), is ideal. However, to achieve the magnetic pole arrangement shown in FIG. 3(C), the required magnetizing yoke design is highly difficult. Furthermore, the assembly process is difficult because it is difficult to position the magnet axially and circumferentially relative to the shaft, making it difficult to attach the magnet to the shaft. In other words, achieving the magnetic pole arrangement shown in FIG. 3(C) poses problems related to the difficulty of magnet manufacturing and assembly. Therefore, as shown in FIG. 1, in the permanent magnet 100 of embodiment 1, by magnetizing a cylindrical magnet into multiple diamond shapes, the difficulty of magnet manufacturing and assembly can be reduced. Note that even if the first pole 1 and the second pole 2 are magnetized to form diamond shapes, it is difficult to accurately magnetize the four corners so that the apexes are pointed. Therefore, the apexes of the magnetized four corners may be rounded. Furthermore, magnets of the same pole may be partially connected.

[0013] As described above, the permanent magnet 100 used in the direct acting rotation actuator according to this embodiment can obtain a magnetic flux that can drive the actuator in both the direct acting direction and the rotational direction by using the first pole group and the second pole group, thereby realizing a direct acting rotation actuator that can drive in both the direct acting direction and the rotational direction. Therefore, the direct acting rotation actuator can be applied to the mechanism at the tip of a robot arm that handles various parts, for example, in electronic component mounting equipment or semiconductor manufacturing equipment, where operation in a small space is required.

[0014] Embodiment 2 Next, a permanent magnet 101 used in the direct acting rotation actuator according to embodiment 2 will be described. Fig. 4 is a perspective view showing a permanent magnet used in the direct acting rotation actuator according to embodiment 2. Fig. 5 is an explanatory diagram showing the direction of magnetic flux at the V portion shown in Fig. 4 as viewed from the outer peripheral surface side in the radial direction of the permanent magnet.

[0015] As shown in FIG. 4 , the permanent magnet 101 in the second embodiment is cylindrical and has multiple magnetic poles on the surface facing the armature or mover. The cylindrical permanent magnet 101 is magnetized into multiple diamond shapes. Specifically, the permanent magnet 101 has a first pole group having one or multiple equally spaced first poles 1 in the circumferential direction that generate magnetic flux from the outer diameter side to the inner diameter side in the radial direction, and a second pole group having one or multiple equally spaced second poles 2 in the circumferential direction that generate magnetic flux from the inner diameter side to the outer diameter side in the radial direction. Here, the first pole is an S pole and the second pole is an N pole. The first pole group is positioned at a predetermined axial distance from the second pole group and circumferentially shifted by 180 electrical degrees.

[0016] 4 and 5, the thin-walled intermediate portion 3, which is the magnet space region between the magnetic poles, is magnetized so that the magnetic flux is directed from the first pole 1 to the adjacent second pole 2 when the opposing surfaces are the outer peripheral surfaces of a cylinder. Note that the intermediate portion 3, which is the magnet space region between the magnetic poles, is magnetized so that the magnetic flux is directed from the second pole 2 to the adjacent first pole 1 when the opposing surfaces are the inner peripheral surfaces of a cylinder. Permanent magnet 101 in embodiment 2 has an intermediate portion 3 that is magnetized so that the magnetic flux is directed from the first pole 1 to the adjacent second pole 2, allowing for more effective use of the magnetic flux.

[0017] Note that even if the permanent magnet 101 is magnetized so that the first pole 1 and the second pole 2 are diamond-shaped, it is difficult to accurately magnetize the four corners so that they are sharp. Therefore, the magnetized four corners may be rounded. Also, magnets of the same pole may be partially connected.

[0018] Embodiment 3 Fig. 6 is a perspective view of a permanent magnet used in a direct acting rotation actuator according to a third embodiment, with a magnetic pole aspect ratio of 1:1. Fig. 7 is a perspective view of a permanent magnet used in a direct acting rotation actuator according to a third embodiment, with a magnetic pole aspect ratio of 2:1. The magnetic pole aspect ratio is the ratio of the diagonal length in the circumferential direction of the magnetic pole to the diagonal length in the axial direction.

[0019] As shown in Figure 6, in permanent magnet 102A with a magnetic pole aspect ratio of 1:1, the diagonal length in the linear direction of the diamond-shaped magnet is equal to the diagonal length in the rotational direction. As shown in Figure 7, in permanent magnet 102B with a magnetic pole aspect ratio of 2:1, the diagonal length in the linear direction of the diamond-shaped magnet is 0.5 times the diagonal length in the rotational direction.

[0020] FIG. 8 is a perspective view schematically illustrating an example of a direct acting rotation actuator having the permanent magnet shown in FIG. 6. FIG. 9 is a perspective view schematically illustrating an example of a direct acting rotation actuator having the permanent magnet shown in FIG. 7. A direct acting rotation actuator 500A shown in FIG. 8 includes a permanent magnet 102A constituting a mover, a shaft 200 fitted into the inner circumferential surface of the permanent magnet 102A, a cylindrical pole core 300 serving as an armature, and a coil 400 located inside the pole core. A direct acting rotation actuator 500B shown in FIG. 9 includes a permanent magnet 102B constituting a mover, a shaft 200 fitted into the inner circumferential surface of the permanent magnet 102B, a cylindrical pole core 300 serving as an armature, and a coil 400 located inside the pole core. The inner circumferential surface of the coil 400 faces the outer circumferential surfaces of the permanent magnets 102A and 102B. The permanent magnet 102A of the direct acting rotation actuator 500A shown in Fig. 8 has a magnetic pole aspect ratio of 1:1. The permanent magnet 102B of the direct acting rotation actuator 500B shown in Fig. 9 has a magnetic pole aspect ratio of 2:1. In the direct acting rotation actuators 500A and 500B, a magnetic gap S is generated between the permanent magnets 102A and 102B and the coil 400.

[0021] Fig. 10 is a magnetic flux density contour diagram for the cross section of the direct acting rotation actuator shown in Fig. 8. Fig. 11 is a magnetic flux density contour diagram for the cross section of the direct acting rotation actuator shown in Fig. 9. The direct acting rotation actuator 500A shown in Fig. 10 and the direct acting rotation actuator 500B shown in Fig. 11 have different magnetic flux density contour diagrams for the permanent magnets 102A, 102B, the magnetic pole core 300, the coil 400, and the magnetic gap S. As shown in Fig. 10, in the direct acting rotation actuator 500A using the permanent magnet 102A in which the circumferential diagonal length of the magnetic pole is equal to the axial diagonal length, the magnetic flux density of the magnetic pole core 300 is made more uniform than in the direct acting rotation actuator 500B shown in Fig. 11, and therefore the magnetic characteristics can be improved.

[0022] To improve magnetic properties, the axial and circumferential diagonal lengths of the magnetic poles need not necessarily be exactly equal. It is sufficient that the ratio K of the axial diagonal length to the circumferential diagonal length of the magnetic poles satisfies 0.6≦K≦1.4. If K does not satisfy 0.6≦K≦1.4, i.e., if K is significantly different from 1.0, the magnetic flux density distribution in the magnetic pole core 300 may be biased toward either the linear or rotational direction, resulting in magnetic saturation and ineffective utilization of the magnetic flux, potentially resulting in a decrease in the induced voltage constant. In an actuator with a low induced voltage constant, a large current is required to generate the same torque in both the linear and rotational directions, resulting in large copper loss. Therefore, the range of K is determined by focusing on copper loss to minimize copper loss. The K at which copper loss is minimized varies slightly depending on the shape of the rotor. Therefore, the range of K must be set within a fairly wide range. Therefore, for the copper loss ratio normalized at K=1, the copper loss ratio of 1.1 is set as the threshold, and the range of K is set as 0.6≦K≦1.4, where the copper loss ratio is 1.1 or less.

[0023] Embodiment 4 FIG. 12 is a perspective view showing a permanent magnet used in a linear motion rotation actuator according to a fourth embodiment. The permanent magnet 103 of the fourth embodiment shown in FIG. 12 is configured by combining multiple diamond-shaped magnets 40, 41 arranged on a surface facing the armature or mover constituting the linear motion rotation actuator. Specifically, the permanent magnet 103 is configured by attaching multiple diamond-shaped magnets 40 having a first pole 1 and multiple diamond-shaped magnets 41 having a second pole 2 to a shaft (not shown). Like the permanent magnet 100 shown in FIG. 1, the permanent magnet 103 shown in FIG. 12 also generates magnetic flux capable of driving in the linear motion direction and the rotational direction. Ideally, the diamond-shaped magnets 40, 41 shown in FIG. 12 have pointed corners, but the corners may also be rounded. Magnets of the same pole may be partially connected.

[0024] FIG. 13 is a perspective view showing a first modification of the permanent magnet used in the linear rotary actuator according to the fourth embodiment. FIG. 14 is a side view seen from the direction A shown in FIG. 13. The permanent magnet 103 of the first modification shown in FIGS. 13 and 14 has grooves 50 formed along the axial direction at two opposing locations on its inner circumferential surface. The grooves 50 function as guides when a shaft (not shown) is fitted into the cylindrical interior of the permanent magnet 103, which is formed by combining a plurality of diamond-shaped magnets 40 and 41. The shaft has protrusions formed at positions corresponding to the grooves 50 that fit into the grooves 50. This facilitates positioning of the shaft to be fitted into the inner circumferential surface of the permanent magnet 103, thereby simplifying the assembly process for manufacturing the linear rotary actuator. The grooves 50 are not limited to the semicircular shape shown in the figure and may be rectangular, for example. The grooves 50 are not limited to the two locations shown in the figure and may be provided in one or more locations on the inner circumferential surface of the permanent magnet 103.

[0025] FIG. 15 is a perspective view showing a second modification of the permanent magnet used in the linear rotation actuator according to the fourth embodiment. The permanent magnet 103 of the second modification shown in FIG. 15 has two axially extending protrusions 51 at two opposing locations on its inner circumferential surface. Like the grooves 50, the protrusions 51 function as a guide when a shaft (not shown) is fitted into the cylindrical interior of the permanent magnet 103, which is formed by combining a plurality of magnets 40 and 41. The shaft has a groove formed at a position corresponding to the protrusions 51 to fit into the protrusions 51. The protrusions 51 may have a protruding shape that fits into a groove in a spline shaft. This allows the protrusions 51 to function as a guide when fitting the shaft, as well as a rotation stopper in the rotation direction. The shape of the protrusions 51 is not limited to the semicircular shape shown in the figure, and may be rectangular, for example. The number of protrusions 51 is not limited to the two locations shown in the figure, and may be one or more than two locations on the inner circumferential surface of the permanent magnet 103. Furthermore, the magnets constituting the permanent magnet 103 in the fourth embodiment are not limited to the diamond shape shown in FIGS. 12 to 15, and may have other shapes.

[0026] Embodiment 5. Next, a permanent magnet 104 used in the direct acting rotation actuator according to the fifth embodiment will be described. Fig. 16 is a perspective view showing a permanent magnet used in the direct acting rotation actuator according to the fifth embodiment. Fig. 17 is a perspective view showing one small magnet that constitutes the permanent magnet in the fifth embodiment. Fig. 18 is a perspective view showing the other small magnet that constitutes the permanent magnet in the fifth embodiment. The dotted arrows in Figs. 17 and 18 indicate the magnetization orientation.

[0027] As shown in FIG. 16 , the permanent magnet 104 of the linear motion rotation actuator according to the fifth embodiment is formed by combining two types of small magnets 10 and 11, each divided into multiple pieces. Each small magnet 10 and 11 is fan-shaped, and its inner circumferential surface is attached to the surface of the shaft 200. As shown in FIG. 17 , one small magnet 10 is magnetized from corner 3 to corner 1, which are diagonal corners, of the four corners on its outer circumferential surface. As shown in FIG. 18 , the other small magnet 11 is magnetized from corner 2 to corner 4, which are diagonal corners, of the four corners on its outer circumferential surface. As shown in FIG. 16 , the permanent magnet 104 is arranged with four small magnets 10 and 11 alternately arranged in the circumferential direction. Furthermore, the permanent magnet 104 is arranged with four small magnets 10 and 11 alternately arranged in the axial direction. The permanent magnet 104 has four adjacent small magnets 10, 11 as a group, and the magnetic flux orientation of each small magnet 10, 11 is concentrated at the point where the four small magnets 10, 11 contact each other. This makes it possible for the permanent magnet 104 of embodiment 5 to reproduce the permanent magnet 100 of embodiment 1. The number of small magnets 10, 11 that make up the permanent magnet 104 is not limited to the number shown. For example, the small magnets 10, 11 arranged in the circumferential direction may be arranged so that the total number is an integer multiple of two.

[0028] FIG. 19 is a perspective view showing a modified example of one of the small piece magnets constituting the permanent magnet in embodiment 5. FIG. 20 is a perspective view showing a modified example of the other small piece magnet constituting the permanent magnet in embodiment 5. The dotted arrows in FIGS. 19 and 20 indicate the magnetization orientation. Each small piece magnet 10A, 11A is fan-shaped, and its inner peripheral surface is attached to the surface of the shaft 200. The small piece magnet 10A shown in FIG. 19 differs from the small piece magnet 10 shown in FIG. 17 in that it is magnetized so that it extends from the outer diameter side to the inner diameter side in the radial direction from corner 3 to corner 1, which are diagonal corners of the four corners of the outer peripheral surface, and then extends back to the outer diameter side. The other small piece magnet 11A shown in FIG. 20 differs from the small piece magnet 11 shown in FIG. 18 in that it is magnetized so that it extends from the outer diameter side to the inner diameter side in the radial direction from corner 2 to corner 4, which are diagonal corners of the four corners of the outer peripheral surface, and then extends back to the outer diameter side. By orienting the magnetic flux in this way, the performance of the magnet can be improved.

[0029] The permanent magnet 104 for the linear rotation actuator according to the fifth embodiment is formed by combining two types of small magnets 10 and 11 which are divided into multiple pieces, and is easier to manufacture than a permanent magnet magnetized into a diamond shape, which can contribute to reducing manufacturing costs.

[0030] As shown in FIGS. 13 to 15, the permanent magnet 104 in the fifth embodiment may have a groove 50 or a protrusion 51 formed on the inner peripheral surface along the axial direction.

[0031] Embodiment 6 A description will be given of the permanent magnet 105 used in the direct acting rotation actuator according to the sixth embodiment. Fig. 21 is a perspective view showing the permanent magnet used in the direct acting rotation actuator according to the sixth embodiment.

[0032] As shown in FIG. 21 , the permanent magnet 105 of the linear motion rotation actuator according to the sixth embodiment is configured by combining multiple divided diamond-shaped magnets 40, 41 and multiple bar-shaped magnets 42. The diamond-shaped magnet 40 has a first pole 1. The diamond-shaped magnet 41 has a second pole 2. The bar-shaped magnets 42 are disposed in the thin-walled intermediate portion, which is the magnetic space between the magnetic poles, and are magnetized so that the magnetic flux is directed from the first pole 1 to the adjacent second pole 2 when the opposing surface is the outer circumferential surface of a cylinder. Note that the intermediate portion where the bar-shaped magnets 42 are disposed is magnetized so that the magnetic flux is directed from the second pole 2 to the adjacent first pole 1 when the opposing surface is the inner circumferential surface of a cylinder.

[0033] As shown in FIGS. 13 to 15, the permanent magnet 105 in the sixth embodiment may have a groove 50 or a protrusion 51 formed on the inner peripheral surface along the axial direction.

[0034] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention. [Explanation of symbols]

[0035] 1 first pole, 2 second pole, 3 intermediate portion, 10, 10A, 11, 11A small piece magnet, 40, 41, 42 magnet, 50 groove portion, 51 protrusion portion, 100, 101, 102A, 102B, 103, 104, 105 permanent magnet, 200 shaft, 300 magnetic pole core, 400 coil, 500A, 500B direct acting rotary actuator.

Claims

1. A cylindrical permanent magnet used in a direct acting rotation actuator, the permanent magnet having a plurality of magnetic poles on a surface facing an armature or a mover that constitutes the direct acting rotation actuator, A cylindrical magnet is magnetized to have multiple magnetic poles, a first pole group having one first pole or a plurality of first poles equally spaced in a circumferential direction, the first pole generating a magnetic flux from an outer diameter side to an inner diameter side in the radial direction on the opposing surface; a second pole group having one second pole or a plurality of second poles at equal intervals in the circumferential direction, the second pole generating a magnetic flux from the inner diameter side to the outer diameter side in the radial direction; the first pole group is disposed at a position spaced a predetermined distance from the second pole group in the axial direction and shifted in phase by an electrical angle of 180 degrees in the circumferential direction, The magnet region between the magnetic pole centers of the N pole or the S pole appearing on the opposing surface of the second pole adjacent to the first pole is magnetized so that the direction of magnetic flux penetrates from the outer diameter side to the inner diameter side in the radial direction and then exits to the outer diameter side. A permanent magnet used in a linear acting rotation actuator.

2. In the permanent magnet, the magnetization direction between the poles continuously changes in a magnet region between the magnetic pole centers of the N pole or the S pole appearing on the opposing surface of the second pole adjacent to the first pole.

2. A permanent magnet used in the direct acting rotation actuator according to claim 1.

3. A cylindrical permanent magnet used in a direct acting rotation actuator, the permanent magnet having a plurality of magnetic poles on a surface facing an armature or a mover that constitutes the direct acting rotation actuator, It is made into a cylindrical shape by combining two types of small fan-shaped magnets, each divided into multiple pieces. One of the small magnet pieces is magnetized from one diagonal corner to the other of the four corners on the outer circumferential surface, The other small magnet is magnetized from one corner to the other diagonal corner different from one of the four corners of the outer peripheral surface, The two types of small magnets are alternately arranged in the circumferential direction, and the two types of small magnets are alternately arranged in the axial direction, and are arranged so that the orientation of the magnetic flux of each of the small magnets is concentrated at one point where the four small magnets are in contact, a first pole group having one first pole or a plurality of first poles equally spaced in a circumferential direction, the first pole generating a magnetic flux from an outer diameter side to an inner diameter side in the radial direction on the opposing surface; a second pole group having one second pole or a plurality of second poles at equal intervals in the circumferential direction, the second pole generating a magnetic flux from the inner diameter side to the outer diameter side in the radial direction; the first pole group is disposed at a position spaced a predetermined distance from the second pole group in the axial direction and shifted in phase by an electrical angle of 180 degrees in the circumferential direction, a magnet region between the magnetic pole centers of the N pole or the S pole appearing on the opposing surface of the second pole adjacent to the first pole is magnetized so that the direction of the magnetic flux has at least a circumferential component; A permanent magnet used in a linear acting rotation actuator.

4. The permanent magnet has a ratio K of the axial diagonal length of the magnetic pole to the circumferential diagonal length thereof satisfying 0.6≦K≦1.

4.

4. A permanent magnet used in the direct acting rotation actuator according to claim 1.

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