Electromagnetic device

Abstract

The present invention provides an electromagnetic device in which a field magnet part is opposed to an armature part for a relative movement, the field magnet part having a plurality of permanent magnets arranged so that the magnetizing direction is changed in order by a set angle θ each time and the length is a natural-number multiple of the length of one magnetic pole cycle. In the armature part, coils in each phase are arranged in order and the coils in the same phase are connected to each other so that a similar current flows through each coil. With this arrangement, even when a change in a distribution of magnetic flux interlinking the coils occurs in an end portion in the direction of the movement of the field magnet part, the electromagnetic device can suppress the end effect in which this change occurs to some of the coils, thereby effectively suppressing a thrust ripple caused by the end effect.

Description

electromagnetic device

[0001] The disclosed technology relates to a moving magnet type electromagnetic device in which a field magnet moves relative to an armature coil.

[0002] Japanese Patent Application Laid-Open Publication No. 2003-209963 describes a linear motor having field poles with a Halbach array structure, in which first main poles are disposed at both ends of a yoke of field poles that move relative to an armature, second main poles are disposed at positions other than both ends of the yoke, a first sub-pole is disposed between the first and second main poles, and a second sub-pole is disposed between the second main poles.

[0003] In addition, in the linear motor, the width of the first main magnetic pole is narrower than the width of the second main magnetic pole, and the width of the first sub-magnetic pole is wider than the width of the second sub-magnetic pole.

[0004] In the above-described linear motor, in order to suppress the influence of the end effect in the Halbach array, permanent magnets with different widths as well as different magnetization directions are required.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic device that can effectively suppress thrust ripples caused by end effect.

[0006] To achieve the above object, a first aspect of the electromagnetic device includes: a field section in which a movable body that moves relatively in the longitudinal direction of a long fixed body has a plurality of permanent magnets arranged so that the magnetization direction is changed in sequence by an angle obtained by dividing one electrical angle cycle corresponding to one magnetic pole cycle by the number of divisions n, where n is any one of three or more integers, and the length of the field section is a natural number multiple of the length of one electrical angle cycle along the direction of movement of the movable body; and an armature section that is provided on the fixed body and has a plurality of sets of armature coils, each set corresponding to the number of phases, arranged in the longitudinal direction of the fixed body within the movement range of the movable body, and power is supplied so that the same current flows through each of the armature coils of the same phase.

[0007] In the electromagnetic device of the first aspect, a movable body is moved relative to a fixed body. A field magnet portion is disposed on the movable body. The field magnet portion has a plurality of permanent magnets arranged along the direction of movement of the movable body, the magnetization direction of which is sequentially changed by an angle obtained by dividing one electrical angle cycle corresponding to one magnetic pole cycle by the number of divisions n, where n is any one of integers equal to or greater than 3, and the length of one electrical angle cycle (one magnetic pole cycle) is a natural number multiple (an integer multiple of 1 or greater) of the length of one electrical angle cycle (one magnetic pole cycle).

[0008] An armature section is disposed on the fixed body, and multiple sets of armature coils, one set for each phase, are arranged in the longitudinal direction of the fixed body within the range of movement of the movable body. The armature coils are also arranged throughout the range of movement of the field section that moves together with the movable body, and by supplying the required AC power to the multiple-phase armature coils, thrust generated between the armature coils and the field section can move the movable body together with the field section.

[0009] Here, the armature coils of each phase are configured so that the same current flows through each of the armature coils of the same phase. In this case, the armature coils of the same phase may be connected in series, or power may be supplied so that the same current flows between the armature coils of the same phase. This prevents a change in the distribution of magnetic flux linking the armature coils at the ends (both ends) of the field section in the direction of movement from appearing in some of the armature coils, thereby effectively suppressing thrust ripple due to the end effect.

[0010] The electromagnetic device of the second aspect includes a movable body that moves relatively in the longitudinal direction of a long fixed body, the movable body including: a field section in which a plurality of permanent magnets are arranged so that the magnetization direction is changed in sequence by an angle obtained by dividing one electrical angle cycle corresponding to one magnetic pole cycle by the division number n, where n is any one of integers equal to or greater than 3, and the length along the direction of movement of the movable body is a natural number multiple of the length of one electrical angle cycle; an armature section that is provided on the fixed body, and in which a plurality of sets of armature coils, each set corresponding to the number of phases, are arranged in the longitudinal direction of the fixed body within the movement range of the movable body; and a power supply section that supplies power to each of the armature coils of the armature section so that the same current flows between armature coils of the same phase when power is supplied to each of the armature coils of the armature section to move the movable body.

[0011] The electromagnetic device of a third aspect is the first aspect, and includes a power supply unit that supplies power to each of the armature coils so that the same current flows between the armature coils of the same phase when the moving body is moved.

[0012] A fourth aspect of the electromagnetic device is the second or third aspect, wherein the power supply unit supplies power to the armature coils in a range where magnetic flux from the field magnet unit of the moving body intersects with each other so that the same current flows through each of the armature coils of the same phase.

[0013] A fifth aspect of the electromagnetic device is any one of the second to fourth aspects, wherein the power supply unit supplies power to the armature coils of the same phase within a range of a length equivalent to half a magnetic pole period from each of both ends of the arrangement of the permanent magnets, so that the same current flows through each of the armature coils of the same phase.

[0014] The electromagnetic device of a sixth aspect is the fourth or fifth aspect, and includes a detection means that is provided on the fixed body facing the field magnet portion and detects magnetic flux to detect the arrangement of the permanent magnets, and the power supply unit supplies power to the armature coil in accordance with the detection result of the detection means.

[0015] The seventh aspect of the electromagnetic device is any one of the first to sixth aspects, and includes that the length Lc of the arrangement of one set of the armature coils is a natural number multiple of the length Lm of one period of the magnetic poles of the permanent magnet.

[0016] An electromagnetic device of an eighth aspect is any one of the first to sixth aspects, and includes that the length of the arrangement of the armature coils in the armature section is a natural number multiple of the length Lc of the arrangement of one set of the armature coils.

[0017] A ninth aspect of the electromagnetic device is any one of the first to eighth aspects, wherein the field magnet section includes a first magnet arrangement and a second magnet arrangement, each of which has the plurality of permanent magnets arranged therein, and the first magnet arrangement and the second magnet arrangement are opposed to each other across the armature coil so that the magnetic fields formed by them reinforce each other.

[0018] The electromagnetic device of a tenth aspect is any one of the first to eighth aspects, and includes that the armature portion has a ferromagnetic material arranged in the arrangement range of the multiple armature coils on the opposite side of the armature coil from the field portion.

[0019] According to the disclosed technology, the electromagnetic device can suppress thrust ripple caused by the end effect by the current flowing through the armature coil, thereby providing the advantage of being able to effectively suppress thrust ripple caused by the end effect.

[0020] 4A is a schematic diagram of a main part of an example of an electromagnetic device according to the present embodiment; FIG. 1B is a schematic diagram showing a magnetic flux density distribution in the electromagnetic device of FIG. 1A; FIG. 1C is a schematic diagram showing a main part and magnetic flux density distribution of an electromagnetic device in which a Halbach magnet arrangement is applied to the electromagnetic device of FIG. 1A; FIG. 1D is a diagram showing an outline of a change in magnetic flux density with respect to the position of a magnet arrangement for one magnetic pole period; FIG. 1E is a diagram showing an example of a change in voltage due to back electromotive force in the electromagnetic device of FIG. 1A; FIG. 1F is a diagram showing an example of a change in torque in the electromagnetic device of FIG. 1A; FIG. 4A is a schematic diagram showing a main part and magnetic flux density distribution of another example of an electromagnetic device according to the present embodiment; FIG. 4B is a schematic diagram showing a main part and magnetic flux density distribution of an electromagnetic device in which a dual Halbach magnet arrangement is applied to the electromagnetic device of FIG. 4A; FIG. 2 is a plan view of the main part of the vibration device.

[0021] Embodiments of the present disclosure will be described in detail below with reference to the drawings. An electromagnetic device according to this embodiment is applied with two or more phases of AC power. The electromagnetic device includes a field section in which a plurality of permanent magnets are arranged, and an armature section in which armature coils are arranged in a number of phases corresponding to the AC power. In the electromagnetic device, the armature section is disposed on a fixed body, and the field section is disposed on a moving body, and in the electromagnetic device, the length of the armature coil arrangement in the armature section is longer than the length of the magnet arrangement in the field section. In the electromagnetic device, thrust generated between the armature coils and the permanent magnets functions as a drive source for moving the moving body (movement in one direction or reciprocating movement) within the range of the length of the armature coil arrangement.

[0022] The electromagnetic device can function as a power generating device that generates electric power in an armature coil when a moving object is moved. The following description will be given using an example of an electromagnetic device that functions as a driving source in various moving devices, etc. In the disclosed technology, "same" not only means that the shape, size, numerical values, and numerical value changes are the same, but also includes a range in which the shape, size, numerical values, and numerical value changes can be considered similar. In the following description, "similar" includes being identical.

[0023] 1A and 1B show schematic configuration diagrams of the main parts of an electromagnetic device 10 according to this embodiment, and Fig. 2 shows a schematic configuration diagram of the main parts of an electromagnetic device 12 corresponding to the electromagnetic device 10. In the following description, the arrangement direction of the permanent magnets and armature coils is defined as the thrust direction, and in the drawings, the thrust direction (also referred to as the movement direction) is indicated by arrow Y. Fig. 1B also shows the distribution of magnetic field lines (magnetic flux density distribution) in the electromagnetic device 10, and Fig. 2 shows the distribution of magnetic field lines (magnetic flux density distribution) in the electromagnetic device 12.

[0024] 1A, the electromagnetic device 10 includes an armature section 14 disposed on a fixed body, and a field section 16 disposed on a moving body opposite the armature section 14. In the electromagnetic device 10, a plurality of armature coils (hereinafter referred to as coils) 18 are disposed in the armature section 14, and a plurality of permanent magnets 20 are disposed in the field section 16, with the coils 18 and the permanent magnets 20 each arranged along the thrust direction.

[0025] Furthermore, in the electromagnetic device 10, the length of the armature section 14 along the thrust direction (the total length of the arrangement of the coils 18) is longer than the length of the field section 16 (the total length of the arrangement of the permanent magnets 20). As a result, in the electromagnetic device 10, the field section 16 moves relatively along the arrangement direction of the plurality of coils 18 (thrust direction) within the range of the arrangement of the plurality of coils 18 in the armature section 14. Note that the arrangement direction of the plurality of coils 18, which is the thrust direction, is not limited to a direction along a plane and may include a direction along a curved surface of an arc shape. However, for the sake of simplicity, the thrust direction will be described below as a direction along a plane.

[0026] The permanent magnets 20 of the field magnet section 16 each have the same outer diameter shape (size), and the same cross-sectional shape (hereinafter simply referred to as cross-sectional shape) taken along the thrust direction and the vertical direction (a direction intersecting a plane along the thrust direction, the vertical direction on the page). The permanent magnets 20 have a rectangular cross-sectional shape. In the following description, "similar" includes identical and shapes and sizes that can be considered identical. Furthermore, the cross-sectional shape of the permanent magnets 20 is not limited to a rectangular shape, and any shape that is similar among multiple permanent magnets 20 may be used. Depending on the attachment to the moving body, the thrust direction, etc., shapes such as an isosceles triangle or other triangular shape, a trapezoid, a sector shape, a circle, etc. may also be used.

[0027] In the field magnet portion 16, a Halbach magnet array is used to arrange the permanent magnets 20. In the Halbach magnet array, the number of divisions n is an integer equal to or greater than three, and the set angle θ is the angle obtained by dividing one electrical angle period (2π = 360°) corresponding to one magnetic pole period (two magnetic poles) by the number of divisions n. In the Halbach magnet array, the permanent magnets 20 are arranged in order, with the magnetization direction changed by the set angle θ. Note that the magnetization direction is from the south pole to the north pole inside the permanent magnet 20 (in the cross section) (the direction indicated by the arrow in each permanent magnet 20 in FIG. 1A ).

[0028] As an example, the field magnet portion 16 has a division number n=12 and a set angle θ of 30° (θ=30°). In the field magnet portion 16, the length of one magnetic pole period corresponding to one electrical angle period in the arrangement direction of the permanent magnets 20 is set to length Lm, and 12 permanent magnets 20A to 20L are arranged in order within the length Lm to form the magnet array 22. As a result, if the magnet array 22 has two magnetic poles, the angle between the magnetization directions of adjacent permanent magnets 20 is set to set angle θ (=30°). Note that the field magnet portion 16 may be formed such that the overall length in the arrangement direction is a natural number multiple (an integer multiple of 1 or greater) of the length Lc by arranging one or more magnet arrays 22.

[0029] In the field magnet section 16, the Halbach magnet arrangement suppresses (weakens) the magnetic field on one side in a direction intersecting the arrangement direction of the permanent magnets 20, and strengthens the magnetic field on the other side compared to the magnetic field on the one side. In the field magnet section 16, the side where the magnetic field is strengthened is the armature section 14 side.

[0030] The electromagnetic device 10 uses multi-phase AC power, and the number of phases of the AC power can be two or three or more. As an example, the electromagnetic device 10 uses three-phase AC power. The armature section 14 is arranged with a plurality of coil arrangements 24, each of which includes a set of coils 18 for each phase (U-phase coil 18U, V-phase coil 18V, and W-phase coil 18W). Each coil 18 uses a litz wire for its winding, and each coil 18 is air-core (it is sufficient that it is magnetically air-core).

[0031] In the armature section 14, the coils 18 (18U, 18V, 18W) are arranged at required gap intervals, and a plurality of coil arrangements 24 are arranged along the thrust direction and disposed on a support 26. In the armature section 14, the length of one electrical angle cycle corresponding to the length of one set of coils 18U to 18W (coil arrangements 24) is designated as Lc. Note that the length Lc of one electrical angle cycle is the length (distance) of the gap intermediate positions between the coil arrangements 24 on either side of this coil arrangement 24, and is defined as the length from the center position of the gap between coil 18W and coil 18U to the center position of the gap between the next coil 18W and coil 18U.

[0032] 2, the electromagnetic device 12 corresponds to the electromagnetic device 10, and includes an armature portion 14 and a field portion 28 facing the armature portion 14. The field portion 28 has a plurality of magnet arrangements (corresponding to the magnet arrangement 22) arranged along the thrust direction, each set consisting of permanent magnets 20A to 20L whose magnetization directions are shifted by a predetermined set angle θ. As a result, a general Halbach array field magnet that is longer than the field portion 16 is applied to the field portion 28.

[0033] In the field magnet section 28, focusing on one set of permanent magnets 20A-20L and the permanent magnet 20A adjacent to the permanent magnet 20L, the distance (length) between the midpoint of one permanent magnet 20A in this arrangement and the midpoint of the other permanent magnet 20A is the length Lm of one magnetic pole period. If this portion is designated as a magnet array 30, the field magnet section 28 becomes a Halbach magnet array in which the number of interlinking magnetic fluxes interlinking with the coil 18 changes sinusoidally within the range of each magnet array 30. Therefore, the field magnet section 28, which has multiple arrays of permanent magnets 20A-20L (corresponding to magnet array 22), is configured by arranging multiple magnet arrays 30.

[0034] 1B shows a field magnet section 16A in which the magnet arrangement 22 of the field magnet section 16 in the electromagnetic device 10 is replaced with a magnet arrangement 30. In FIG. 1B, the length of the permanent magnet 20A along the arrangement direction is divided into halves, and the divided permanent magnets 20A are arranged at both ends in the arrangement direction, so that the length of one magnetic pole period is Lm.

[0035] 1B , in field magnet section 16A, the magnetic flux density distribution around permanent magnets 20A at both ends of magnet array 30 in the arrangement direction is different from the magnetic flux density distribution at both ends of magnet array 30 in the arrangement direction when applied to a Halbach magnet array (field magnet section 28). In field magnet section 16A, the difference in magnetic flux density distribution at both ends of magnet array 30 in the arrangement direction causes an end effect in electromagnetic device 10.

[0036] However, by combining the two magnet arrays 30, the magnetic flux density distribution between the two magnet arrays 30 becomes similar to that of the Halbach magnet array (the magnet array 30 in the field magnet portion 28) according to the superposition theorem of electromagnetism.

[0037] In the electromagnetic devices 10 and 12, the length Lm of one magnetic pole period is the same as the length Lc of one electrical angle period (Lm = Lc). Also, in the electromagnetic devices 10 and 12, it is assumed that the start and end points of one magnetic pole period of the magnet arrangement 30 are aligned with the start and end points of one electrical angle period of the coil arrangement 24.

[0038] At this time, focusing on coil 18U, in field magnet section 28 where the Halbach magnet array is configured, the back electromotive force generated in coil 18U varies sinusoidally due to the magnetic flux density distribution of one magnetic pole period of magnet array 30. The voltage between the start and end of winding in coil 18U depends on the vector sum of the magnetic flux of magnet array 30 in one magnetic pole period.

[0039] In contrast, in the field magnet section 16A, the magnetic flux of the permanent magnet 20A at one end of the magnet arrangement 30 links with the coil 18U of the coil arrangement 24 facing the magnet arrangement 30, and the magnetic flux of the permanent magnet 20A at the other end of the magnet arrangement 30 links with the coil 18U of the coil arrangement 24 adjacent to the coil arrangement 24 facing the magnet arrangement 30.

[0040] For this reason, in the field magnet portion 16A, the magnetic flux density distribution for one magnetic pole period of the magnet array 30 generates a back electromotive force in the coil 18U of the coil array 24 facing the magnet array 30 and in the coil 18U of the coil array 24 adjacent to the coil array 24 facing the magnet array 30. Furthermore, in the magnet array 30 for one magnetic pole period in the field magnet portion 28, the vector sum of the magnetic flux at one end of the magnet array 30 and the vector sum of the magnetic flux at the other end of the magnet array 30 match.

[0041] When two coils 18U, one of the coil arrangements 24 facing the magnet array 30 and the other of the coil arrangements 24 adjacent to the coil arrangement 24 facing the magnet array 30, are connected in series, the back electromotive force generated in the two coils 18U by the magnet array 30 varies sinusoidally. In this case, for example, by connecting the end of the winding of the coil 18U of the coil arrangement 24 facing the magnet array 30 with the start of the winding of the coil 18U adjacent to the coil arrangement 24 facing the magnet array 30, the voltage between the start of the winding of the coil 18U of the coil arrangement 24 facing the magnet array 30 and the end of the winding of the coil 18U adjacent to the coil arrangement 24 facing the magnet array 30 depends on the vector sum of the magnetic flux of one magnetic pole period of the magnet array 30.

[0042] That is, in field magnet section 16A, the sum of the number of magnetic flux interlacing two coils 18U due to magnet arrangement 30 is the same as the number of magnetic flux linkages to one coil 18U due to one magnet arrangement 30 in field magnet section 28. Therefore, in field magnet section 16A, the sum of voltages generated in two coils 18U with which magnetic flux due to magnet arrangement 30 is linked is equal to the voltage generated in one coil 18U with which magnetic flux is linked by one magnet arrangement 30 in field magnet section 28.

[0043] 1A and 1B, in the electromagnetic device 10, the multiple coils 18U are electrically connected in series (shown by dashed lines in FIGS. 1A and 1B) along the thrust direction (arrangement direction). As a result, in the field magnet section 16A (similarly in the field magnet section 16), the connection points between adjacent coils 18U in the multiple coils 18U are at the same potential. In the magnet arrangement 22 (magnet arrangement 30) of the electromagnetic device 10, the end effect in the U-phase coil 18U can be suppressed, similar to the magnet arrangement 30 in the field magnet section 28 that uses a Halbach magnet arrangement.

[0044] The effect of magnet arrangement 30 of field magnet portion 16A is similarly achieved in magnet arrangement 22 of field magnet portion 16. Furthermore, the above-described configuration established in coil 18U of one phase can be similarly applied to the configurations of coils 18V, 18W of the other phases, and the occurrence of end effect can also be suppressed in V-phase coil 18V and W-phase coil 18W.

[0045] Therefore, in the electromagnetic device 10, in the multi-phase coil arrangement 24 in which one electrical angle period is length Lc and one magnetic pole period of the magnet arrangement 22 is length Lm, the same current flows between the coils 18 of the same phase, and the coils 18 of the same phase can be considered to be electrically connected in series, thereby suppressing the occurrence of the end effect. Furthermore, even if the length of the field portion 16 is an integer multiple (positive integer multiple) of the length Lm or the length of the armature portion 14 is an integer multiple (positive integer multiple) of the length Lc, the occurrence of the end effect can be suppressed.

[0046] 3A is a diagram showing an outline of the change in magnetic flux density By along the approach / removal direction of the magnet array on the surface of coil 18 facing the magnet array for one magnetic pole period (corresponding to magnet array 22) shown in FIG. 1B. In FIG. 3A, the horizontal axis (x-axis) represents the position on the surface of coil 18 facing the magnet array (the relative position with respect to the magnet array), and the vertical axis (y-axis) represents the direction from coil 18 toward the magnet array. In FIG. 3A, half of the length Lm of one magnetic pole period is set as length τ (τ = Lm / 2), and the point on the horizontal axis corresponding to the center position of the magnet array is set as point 0, and the vertical axis represents magnetic flux density (T).

[0047] As shown in Figure 3A, in a magnet array with a length of Lm, the magnetic flux density is high at the center and both ends of the array. Furthermore, in the space above the coil 18, leakage magnetic flux occurs in the range from position τ to position 2τ, which are off the ends of the magnet array, and in the range from position -τ to position -2τ, and the magnetic flux density is not 0 T. In the electromagnetic device 10, this leakage magnetic flux is one of the causes of the end effect.

[0048] 3B shows a diagram of voltage changes representing the back electromotive force generated in the coil 18 by the magnet array 22 (and similarly for the magnet array 30) for one magnetic pole period in the electromagnetic device 10, and FIG. 3C shows a diagram of the change in torque (thrust torque) generated between the magnet array 22 and the coil 18. In FIG. 3B and FIG. 3C, the horizontal axis represents time (sec), the vertical axis in FIG. 3B represents voltage (V), and the vertical axis in FIG. 3C represents torque (thrust torque) (N). In addition, FIG. 3B and FIG. 3C show the voltage changes and torque changes with time when the magnet array 22 is moved relative to the coil 18 at a predetermined speed.

[0049] In a conveyance device (linear motor) using the electromagnetic device 10 as a drive source, the field magnet portion 16 moves in the direction of (or parallel to) a moving magnetic field formed by flowing multiple (three-phase) alternating currents through multiple (e.g., three-phase) coils. In general, the number of magnetic flux linkages that link one coil facing the Halbach array field magnet changes sinusoidally due to the relative movement between the coil and the field magnet.

[0050] Therefore, in the electromagnetic device 10, the number of magnetic flux linkages in each coil 18 (18U, 18V, 18W) changes sinusoidally as the magnet array 22 moves relative to one another. As a result, as shown in FIG. 3B , in the electromagnetic device 10, the back electromotive force generated in the coil 18 also becomes sinusoidal with harmonic components suppressed (no harmonic components included). Also, as shown in FIG. 3C , in the electromagnetic device 10, an excitation current having the same frequency as the sine wave of the back electromotive force generated in each coil 18 flows through the coil, thereby suppressing ripples in the thrust generated between the magnet array 22 and the coil 18. Therefore, in the electromagnetic device 10, the end effect can be suppressed, and thrust ripples due to the end effect can be effectively suppressed.

[0051] The effect of such an electromagnetic device 10 is not limited to the length of the magnet arrangement in the field magnet section 16 being the length Lm of one magnetic pole period, but the length of the magnet arrangement may be a natural number multiple (an integer multiple of 1 or greater) of the length Lm of one magnetic pole period. Furthermore, the effect of the electromagnetic device 10 only needs to be such that the length of the arrangement of the coils 18 in the armature section 14 is longer than the length of the magnet arrangement in the field magnet section 16 and the length Lc of the arrangement of one set of coils 18 in the armature section 14 is a natural number multiple (an integer multiple of 1 or greater). Furthermore, the effect of the electromagnetic device 10 can be such that the length of the magnet arrangement in the field magnet section 16 is an integer multiple of 1 or greater of the length Lc of the arrangement of one set of coils 18 in the armature section 14.

[0052] [Dual Halbach Array Field Magnet] FIG. 4A shows a schematic configuration diagram of the main parts of an electromagnetic device 50 according to this embodiment, and FIG. 4B shows a schematic configuration diagram of the main parts of an electromagnetic device 60 corresponding to the electromagnetic device 50.

[0053] As shown in Figure 4A, the electromagnetic device 50 has an armature section 52 arranged on a fixed body and a field section 54 provided on a moving body, and the field section 54 is arranged in pairs, with field section 54A and field section 54B sandwiched between them by the armature section 52.

[0054] Magnet array 22 in which permanent magnets 20A-20L are arranged in order is used in field magnet sections 54A and 54B, but magnet array 30 is shown here to facilitate comparison with electromagnetic device 60. Magnet array 30 of field magnet section 54A and magnet array 30 of field magnet section 54B (referred to as magnet array 30 for ease of explanation) are arranged so that the magnetic fields on the opposing sides (armature section 52 sides) are strengthened.

[0055] 4B , the electromagnetic device 60 is provided with an armature section 52 and a field section 62, and the field section 62 is arranged in pairs, with field section 62A and field section 62B sandwiching the armature section 52. The multiple magnet arrangements 22 of field section 62A and the multiple magnet arrangements 22 of field section 62B are arranged so that the magnetic fields on the opposing sides (the armature section 52 sides) are strengthened.

[0056] As a result, in the field magnet section 62 of the electromagnetic device 60, a dual Halbach magnet array is formed using a plurality of magnet arrays 22, and in the field magnet section 62, a dual Halbach array is formed by arranging a plurality of magnet arrays 30 in each of the field magnet sections 62A, 62A, similar to the configuration in which a dual Halbach array is formed.

[0057] 4A and 4B , the length of one magnetic pole period is Lm in each of the field magnet portion 54 of the electromagnetic device 50 and the field magnet portion 62 of the electromagnetic device 60. In addition, in the electromagnetic devices 50 and 60, the length of one electrical angle period of each coil arrangement 24 (one set of coils 18U, 18V, 18W) in the armature portion 52 is Lc.

[0058] As shown in FIG. 4B , in the electromagnetic device 60, the number of interlinking magnetic fluxes of the magnetic fluxes linking one coil 18U varies sinusoidally due to the pair of magnet arrays 30, and the back electromotive force generated in the coil 18U varies sinusoidally due to the magnetic flux density distribution of one magnetic pole period of the pair of magnet arrays 30.

[0059] In contrast, as shown in Figure 4A, in the field section 54, the magnetic flux of the permanent magnet 20A at one end of the pair of magnet arrays 30 links with the coil 18U of the coil array 24 that the pair of magnet arrays 30 face, and the magnetic flux of the permanent magnet 20A at the other end of the pair of magnet arrays 30 links with the coil 18U of the coil array 24 adjacent to the coil array 24 that faces the pair of magnet arrays 30.

[0060] Therefore, in the field magnet section 54, the magnetic flux density distribution over one magnetic pole period of the pair of magnet arrangements 30 generates a back electromotive force in the coil 18U of the coil arrangement 24 facing the pair of magnet arrangements 30, and in the coil 18U of the coil arrangement 24 adjacent to the coil arrangement 24 facing the pair of magnet arrangements 30.

[0061] As shown in FIG. 4A, in the electromagnetic device 50, the length Lm of one magnetic pole period of the pair of magnet arrays 30 is the same as the length Lc of one electrical angle period of the coil array 24 (Lm=Lc).

[0062] Furthermore, in the electromagnetic device 50, for each phase of the coils 18 (18U, 18V, 18W) in the armature section 52, the multiple coils 18 of the same phase are electrically connected in series from one side to the other along the thrust direction (indicated by dashed lines in FIG. 4A ). That is, in the electromagnetic device 50, the end of the winding of one coil 18 is connected to the beginning of the winding of the next coil 18 of the same phase, so that the multiple coils 18 arranged in the thrust direction in each phase are connected in series.

[0063] That is, in the electromagnetic device 50, for example, for the U phase, the sum of the number of magnetic flux intersecting two coils 18U by a pair of magnet arrays 30 is set to be the same as the number of magnetic flux linkages to one coil 18U by a pair of magnet arrays 34 in the electromagnetic device 60. As a result, in the electromagnetic device 50, the sum of voltages generated in two coils 18U linked by magnetic flux by a pair of magnet arrays 30 is set to be equal to the voltage generated in one coil 18U linked by magnetic flux by a pair of magnet arrays 30 in the electromagnetic device 60.

[0064] Therefore, in the electromagnetic device 50, in the multi-phase coil arrangement 24 in which one electrical angle period is length Lc, while the length of one magnetic pole period of the magnet arrangement is length Lm, the same current (current of the same current value) flows through the coils 18 of the same phase, and the coils 18 of the same phase can be considered to be electrically connected in series, thereby suppressing the occurrence of end effect. Moreover, in the electromagnetic device 50, by using the field magnet portion 54, a larger output can be obtained than in the electromagnetic device 10.

[0065] On the other hand, the mirror law in an electric field can also be applied (and holds) to a magnetic field. For this reason, a ferromagnetic material made of electromagnetic steel sheet or the like may be disposed in the armature section 14 facing the field section 16 at a required distance from the field section 16, and the coil arrangement 24 (coils 18) may be disposed between the field section 16 and the ferromagnetic material. In this case, it is preferable that the ferromagnetic material is prevented from being exposed from the coils 18 when viewed from the field section 16 side.

[0066] This allows a magnetic field similar to that of field portion 54 to be formed between field portion 16, in which armature portion 14 is disposed, and the ferromagnetic material. In an electromagnetic device formed in this manner, the field portion can have a simpler structure and be lighter than field portion 54 of electromagnetic device 50, and a larger output can be obtained than with electromagnetic device 10.

[0067] [First Example] Next, a first example according to the present disclosure will be described. In the first example, a conveying device 100 will be described in which a moving magnet type linear motor is used as the electromagnetic device. Fig. 5 shows a perspective view of the main parts of the conveying device 100, Fig. 6 shows a cross-sectional view of the main parts of the conveying device 100 as viewed in the longitudinal direction, and Fig. 7 shows a cross-sectional view of the main parts of the conveying device 100 as viewed from the outside in the width direction. In the drawings, the width direction of the device is indicated by arrow X, the longitudinal direction of the device (direction along the thrust direction) is indicated by arrow Y, and the upper side of the device in the vertical direction is indicated by arrow Z.

[0068] 5 to 7 , the conveying device 100 includes a long track 102 and a conveying platform (conveying carriage) 104. The track 102 includes a base 106 as a fixed body having an upwardly facing cross section (substantially U-shaped) when viewed in the longitudinal direction, a pair of floating guides 108 formed on both sides of the base 106 in the width direction, and an armature unit 110 disposed on the base 106.

[0069] The base 106 has a pair of support portions 106B arranged on both sides of the substrate 106A in the width direction, and the support portions 106B protrude upward from both width direction ends of the substrate 106A. The protruding tip of the support portion 106B protrudes further upward in the device width direction, and a floating guide 108 having a substantially L-shaped cross section is formed at the upper end of the support portion 106B.

[0070] The floating guide 108 has a first surface 108A facing upward and a second surface 108B facing inward in the width direction, and the first surface 108A and the second surface 108B are micro-machined to have a large number of ejection holes (not shown) formed on the surfaces. The transport platform 104 is arranged so as to span between the floating guides 108.

[0071] In the conveying device 100, compressed air is supplied from a compressor or the like (not shown), and the supplied compressed air is ejected from the ejection holes in the first surface 108A and the second surface 108B. As a result, in the conveying device 100, the conveying platform 104 suspended across the levitation guides 108 is supported in a levitated state, and contact between the conveying platform 104 and the track 102 is prevented when the conveying platform 104 moves along the track 102. Note that the conveying platform 104 is not limited to being air-levitated, and may be supported movably on the first surface 108A via a rotating body such as a tire or wheel.

[0072] An armature section 110 is disposed between a pair of support sections 106B on the base 106. In the armature section 110, a plurality of armature coils (coils) 112 are disposed on a long, flat arrangement plate 110A disposed on a substrate 106A of the base 106. The plurality of coils 112 are arranged at predetermined intervals in the longitudinal direction of the arrangement plate 110A.

[0073] The arrangement plate 110A is also provided with a plurality of optical sensors 114 as position detection means, and a plurality of Hall sensors 116 as position detection means and detection means (field detection means). The optical sensors 114 are arranged at one widthwise end of the arrangement plate 110A, and the Hall sensors 116 are arranged at the other widthwise end of the arrangement plate 110A. The optical sensors 114 and the Hall sensors 116 are attached between adjacent coils 112 in the longitudinal direction of the arrangement plate 110A, and a plurality of the optical sensors 114 and the Hall sensors 116 are arranged along the direction of movement of the transport table 104, which is the longitudinal direction of the base 106.

[0074] The optical sensor 114 detects the carriage 104 on the track 102 by determining whether light emitted from a light-emitting unit (not shown) is reflected and reaches a light-receiving unit. A Hall element is used for the Hall sensor 116, which detects the magnetic field generated from the carriage 104 to detect a field magnet part 118 of the carriage 104.

[0075] The conveyance device 100 uses three-phase AC power, and the coils 112 are a U-phase coil 112U, a V-phase coil 112V, and a W-phase coil 112W, each of which is air-core (magnetically air-core). In the armature section 110, the coils 112U, 112V, and 112W are grouped together, and each group is arranged in the longitudinal direction of the track 102 with a predetermined gap between them.

[0076] The transport platform 104 includes a rectangular frame 120, and the frame 120 is supported by being bridged between a pair of floating guides 108, so that the transport platform 104 is arranged to be movable along the track 102. Sliders 124 are arranged at the four corners of the frame 120, and the sliders 124 receive air ejected from the ejection holes of the floating guides 108, so that the frame 120 is supported in a floating state.

[0077] A field magnet section 118 is disposed on the underside of the frame 120. A plurality of permanent magnets 122 are disposed in the field magnet section 118. In the field magnet section 118, the number of divisions n is an integer equal to or greater than three, and the set angle θ is the angle obtained by dividing one electrical angle period (2π = 360°) corresponding to one magnetic pole period (the number of magnetic poles) by the number of divisions n. In the field magnet section 118, the number of divisions n is set to 5, and the set angle θ is set to 72° (θ = 72°). In the field magnet section 118, one magnetic pole period corresponding to one electrical angle period has a length Lm, and five permanent magnets 122A to 122E are arranged in order within the length Lm in the longitudinal direction of the track 102 and face the coil 112.

[0078] As a result, in the conveying device 100, each of the coils 112 is excited, and the conveying platform 104 is moved along the track 102 by the thrust generated between the armature section 110 (coils 112) and the field section 118 (permanent magnets 122).

[0079] On the other hand, the transport device 100 is provided with a driving device 126 as a power supply unit for exciting the coil 112. Figures 8 to 10 show schematic configuration diagrams of the main parts of the driving device 126.

[0080] As shown in FIGS. 8 to 10 , the drive device 126 includes a field detection unit 128 to which the Hall sensor 116 is connected, and an electrical angle detection unit 130 that detects the electrical angle φ of the U-phase coil 112U of the armature unit 110 relative to the field N pole from the output signal of the field detection unit 128.

[0081] The drive device 126 also includes a vector control drive control unit 132, which calculates and outputs target current values ​​itu, itv, and itw of the coils 112 of each phase, which are required for speed control and position control of the field magnet unit 118 (transport table 104), based on the electrical angle φ detected by the electrical angle detection unit 130.

[0082] The driving device 126 also includes a coil excitation unit 134, and a power supply unit 136 is connected to the coil excitation unit 134 to supply power for exciting each of the coils 112. The coil excitation unit 134 excites the coils 112U, 112V, and 112W of each phase near the field unit 118 based on the target current values ​​itu, itv, and itw of the coils 112 of each phase and the output of the field detection unit 128. This allows the driving device 126 to make the current values ​​(target current values) flowing through the coils 112 of the same phase the same for each phase, making it appear as if the coils 112 of the same phase are connected in series.

[0083] In this embodiment, the magnetization direction of the permanent magnet 122C at the center of the conveyance table 104 is downward. This makes it easy to adjust the origin of the moving magnetic field generated by the coil 112 to match the origin of the conveyance table 104 by aligning the center of the permanent magnet 122C with the center position (center of the air core) of the U-phase coil 112. The field magnet portion 118 has a length Lm, which is equivalent to one magnetic pole period corresponding to one electrical angle period.

[0084] From this, the drive unit 126 can select the two coils 112 closest to both ends of the field magnet portion 118 in each of the U-phase, V-phase, and W-phase based on the presence or absence of the conveyance table 104 detected by the optical sensor 114 and the exact position of the field magnet portion 118 detected by the Hall sensor 116. The drive unit 126 also controls the selected coils 112 so that they are excited with the same (identical) excitation current value (target current value).

[0085] Furthermore, when the arrangement length of the permanent magnets 122 is equal to or longer than two electrical angle periods, the driving device 126 controls the coils 112 facing the field magnet section 118 so that the coils 112 other than the coils 112 closest to both ends of each phase are also excited with the same excitation current value as the coils 112 closest to both ends of each phase.

[0086] 9 , the electrical angle detection unit 130 includes a plurality of output selectors 138, a plurality of output adjusters 140, an output calculator 142, and an electrical angle calculator 144. The output selector 138 associates each of the Hall sensors 116 with one of the optical sensors 114 arranged in a direction perpendicular to the traveling direction of the conveyance platform 104 (the direction of the arrow X), and outputs an output indicating whether all three optical sensors 114, for example, the optical sensor 114 corresponding to the U-phase Hall sensor 116U and the optical sensors 114 on either side of it, are detecting the conveyance platform 104. The output adjuster 140 receives the output signals of the Hall sensors 116 of each phase (116U, 116V, 116W) and the output signal of the output selector 138 and classifies the Hall sensors 116 into U-phase Hall sensor 116U, V-phase Hall sensor 116W, and W-phase Hall sensor 116W in a predetermined order.

[0087] An output calculator 142 is provided for each phase (U-phase output calculator 142U, V-phase output calculator 142V, W-phase output calculator 142W), and calculates the sum of the output signals of the output regulator 140 for each phase based on the output of the output selector 138. An electrical angle calculator 144 calculates the electrical angle φ based on the output signals of the phase output calculators 142U to 142W for each phase.

[0088] Here, the output regulator 140 outputs a voltage proportional to the magnetic flux density created by predetermined reference north and south poles from the output signal of the Hall sensor 116, ranging from the negative maximum voltage value to the positive maximum voltage value. When the detected magnetic flux density is zero, the output regulator 140 outputs zero volts.

[0089] 10, the coil excitation unit 134 includes a plurality of excitation selectors 146 and a plurality of excitation devices 148. The excitation selectors 146 are arranged on the center line of the coils 112 and output signals indicating whether or not the optical sensors 114 arranged at the same pitch as the coil pitch and the optical sensors 114 arranged on both sides of the coils 112 corresponding to these optical sensors 114 are detecting the transport table 104.

[0090] An exciter 148 is provided for each phase (exciter 148U, 148V, 148W). When a signal indicating that each optical sensor 114 has detected the conveyance table 104 is input from the output signal of the excitation selector 146, the exciter 148U, 148V, 148W of each phase supplies an excitation current corresponding to the current target value itu, itv, itw of each phase output from the vector control drive control unit 132 to the coil 112 of the corresponding phase.

[0091] Furthermore, when the excitation selector 146 outputs a signal indicating that the optical sensors 114 are not detecting the transport platform 104, the excitation device 148 stops the supply of current to the coils 112 of the corresponding phase. This allows the coil excitation unit 134 to excite only the coils 112 in the vicinity of the transport platform 104, thereby reducing the power consumption required to excite the coils 112.

[0092] In the conveying device 100 configured as described above, when the power is turned on and power is supplied from the power supply 136, the vector control drive control unit 132 begins vector control and excites each coil 112 so that the moving speed of the conveying platform 104 becomes a preset speed. In the conveying device 100, the magnetic poles of the moving magnetic field formed by the excitation of the coils 112 are controlled to a strength corresponding to the moving speed of the field magnet portion 118. As a result, in the conveying device 100, an electromagnetic force from the coils 112 acts on the field magnet portion 118, and the conveying platform 104 begins to levitate and run. At this time, in the conveying device 100, a back electromotive force is generated in each coil 112 by the magnetic field formed by the field magnet portion 118 as the conveying platform 104 moves.

[0093] In this case, the magnetic flux linkage number of the magnetic flux that links the two coils 112 facing the field magnet portion 118 in each phase becomes a sine wave component with the same amplitude but a phase difference of 120°. Therefore, the back electromotive force generated in the coils 112 when viewed from the three-phase power supply side becomes a similar sine wave component, and the excitation current that flows due to the difference between the power supply voltage and the back electromotive force also becomes a sine wave component.

[0094] As a result, between the armature section 110 and the field section 118, the electromagnetic force acting between the magnet array having a length that is an integer (positive integer) multiple of the length Lm of one magnetic pole period and the three-phase coils 112 facing it can be made equal to the electromagnetic force obtained by cutting out an integer (positive integer) multiple of one magnetic pole period from the electromagnetic force acting between the three-phase coils 112 arranged opposite each other in the sinusoidally changing magnetic flux density distribution formed by the Halbach array field.

[0095] In other words, in the conveying device 100, if the length along the arrangement direction of the permanent magnets 122 in the field magnet section 118 is a natural number multiple (an integer multiple of 1 or greater) of the length Lm of one magnetic pole period, a current similar to that flows in the coil 112 near the ends on both sides of the movement direction of the permanent magnet 20 is the same as if the next permanent magnets 122 for one magnetic pole period were connected in succession.

[0096] In addition, in the conveying device 100, the drive device 126 detects the position of the conveying platform 104 on the track 102 using the optical sensor 114 and the Hall sensor 116, and supplies power to the coil 112 facing the conveying platform 104 and to the coils 112 in front of and behind the conveying direction.

[0097] Therefore, in the transport device 100, power can be supplied so that similar currents flow through the coils 112 of the same phase in the range where the magnetic flux from the permanent magnets 122 of the field magnet section 118 intersects. Also, in the transport device 100, power can be supplied so that similar currents flow through the coils 112 of the same phase in the range of a half magnetic pole period from each end of the arrangement of the permanent magnets 122. This allows the transport device 100 to supply power effectively so as to suppress the end effect.

[0098] Therefore, in the conveying device 100, no thrust ripple occurs in the thrust (electromagnetic force) acting between the field magnet section 118 and the armature section 110, so that in the conveying device 100, a smooth thrust acts on the conveying table 104, preventing the generation of vibrations and noise.

[0099] Furthermore, in the transport device 100, the load placed on the transport platform 104 will not collapse or be damaged due to vibrations or the like, and even semiconductor wafers that are easily damaged by vibrations or the like can be transported without being damaged. Furthermore, since the transport device 100 does not generate thrust ripples, the transport platform 104 can be moved and stopped at the target position, and the transport platform 104 can be moved with high precision.

[0100] Furthermore, since the conveying device 100 does not generate thrust ripples, the conveying platform 104 can be accelerated and decelerated according to the target values, and the conveying device 100 can also be used as a vibration tester. Furthermore, since the conveying device 100 obtains the thrust from the sum of the outputs of the Hall sensors 116 corresponding to the coils 112 of each phase located near the field magnet portion 118, the output calculator 142 for each phase can generate a sinusoidal voltage signal with a phase difference of 120° and free of harmonic components. Therefore, in the conveying device 100, the electrical angle calculator 144 accurately calculates the electrical angle φ, and therefore no electromagnetic force that would cause thrust ripples is generated between the excited coils 112 (armature portion 110) and the permanent magnets 122 of the field magnet portion 118.

[0101] Second Example Next, a second example according to the present disclosure will be described. In the second example, a vibration device 200 will be described in which a moving-magnet linear motor is used as an electromagnetic device. In the second example, the Halbach array field magnet, the dual Halbach array field magnet, and functional components similar to those in the first example will be assigned the same reference numerals as those in the Halbach array field magnet, the dual Halbach array field magnet, and the first example, and detailed description thereof will be omitted.

[0102] Figure 11 shows a perspective view of the main parts of the vibration device 200, Figure 12 shows a longitudinal cross-sectional view of the main parts of the vibration device 200, and Figure 13 shows a plan view of the main parts of the vibration device 200.

[0103] 11 to 13 , the vibration excitation device 200 includes a track 202 and a vibration vehicle (vibration table) 204. The track 202 includes a long, flat base 206. A pair of left and right levitation guides 208 are arranged on the upper surface of the base 206, and an armature unit 210 is arranged between the levitation guides 208. Each of the levitation guides 208 includes a strip-shaped base 208A and a guide unit 208B standing on one end in the width direction of the base 208A. The pair of levitation guides 208 are attached to the base 206 with the ends opposite the guide unit 208B facing each other at a predetermined interval. The upper surface of the base 208A of the levitation guide 208 is a first surface 108A, and the inner widthwise surfaces of the guide units 208B are second surfaces 108B.

[0104] The armature section 210 is provided with a plurality of coils 212 (U-phase coil 212U, V-phase coil 212V, and W-phase coil 212W) that are excited by three-phase AC current (AC power), and each coil 212 is molded to have a generally plate-like outer shape (molded coil). The coils 212, each with their longitudinal direction extending vertically, are connected in the width direction, forming a strip-like plate shape. The lower sides of the coils 212, which are one side of the armature section 210 in the width direction, are fitted between the bases 208A of the pair of levitation guides 208. This allows the armature section 210 to stand on the base 206.

[0105] In the vibration excitation device 200, a vibration excitation carriage 204 is disposed as a moving body on a base 206. The vibration excitation carriage 204 is provided with a non-magnetic underframe 214, which is generally box-shaped and open on the lower side and on both sides in the longitudinal direction of the track 202. The lower part of the underframe 214 is disposed between the guide parts 208B of the pair of levitation guides 208, with the armature part 210 inserted from the lower opening.

[0106] A pair of sliders 218, each in the shape of a long block, are arranged on the underframe 214. The sliders 218 are arranged to sandwich the armature unit 210, and are each attached to the lower end of the underframe 214, with each slider 218 facing the first surface 108A and the second surface 108B of the levitation guide 208. As a result, the underframe 214 is levitated and supported by air ejected from the levitation guide 208, and the vibration cart 204 is movable contactlessly along the track 202 while straddling the armature unit 210 erected on the base 206.

[0107] A field magnet section 220 is disposed inside the underframe 214. The field magnet section 220 is provided with a pair of magnet arrays 224, each of which has a plurality of permanent magnets 222 arranged therein. The pair of magnet arrays 224 is attached to the inner surface of the underframe 214, facing the armature section 210. In the field magnet section 220, the number of divisions n in the magnet array 224 is 8, and the set angle θ is 45°. In the field magnet section 220, the initial angle of the arrangement of the permanent magnets 222 in the magnet array 224 is 45°. In the pair of magnet arrays 224, eight permanent magnets 222A to 222H are arranged based on the set angle θ and the initial angle, and are opposed to each other within the underframe 214 so that the magnetic fields therebetween are reinforced.

[0108] In the field magnet section 220, non-magnetic, non-conductive partitions 226 are fitted between adjacent permanent magnets 222 in each magnet arrangement 224. In the field magnet section 220, the sum of the width of the permanent magnets 222 along the arrangement direction and the width (thickness) of the partitions 226 is 1 / 8 (one-eighth) of the length of one electrical angle cycle of the armature section 210, and the thickness of one partition 226 is 1 / 4 (one-fourth) of the width of one permanent magnet 222.

[0109] Furthermore, the overall length (length in the movement direction) of the vibration carriage 204 is set to a length equivalent to two periods of electrical angle formed in the magnet array 224, and the vibration carriage 204 is made shorter by the thickness of one partition wall 226 than the width (dimension along the array direction) of a typical Halbach magnet array with the number of divisions n = 8. For this reason, the frame 214 protrudes from both sides of each of the magnet arrays 224 by half the thickness of the partition wall 226.

[0110] Meanwhile, in the armature section 210, a plurality of optical sensors 114 are arranged on one side in the width direction of the track 202, and a plurality of hall sensors 116 are arranged on the other side in the width direction of the track 202. The optical sensors 114 are used to detect the position of the frame 214 (vibration cart 204) relative to the armature section 210, and the hall sensors 116 are used to detect the magnetic pole position of a magnet array 224 attached to the frame 214 relative to the coil 212.

[0111] In the field magnet section 220 of the excitation device 200, the direction of the magnetic flux in the gap of the center line is the width direction of the track 202 (the direction of the arrow X), and the center line of the excitation cart 204 and the center line of the magnet array 224, the north pole center line of the magnet array 224, and the south pole center line of the magnet array 224 are all aligned. As a result, when performing origin adjustment required to control the position, speed, and thrust of the excitation cart 204, it is sufficient to align the center line of the excitation cart 204 with the center position of the U-phase coil 212U of the coils 212, making origin adjustment easy in the excitation cart 204.

[0112] In the vibration exciter 200, when the driving device 126 controls the travel of the vibration exciter cart 204, two coils 212 closest to the magnet array 224 are selected from the coils 212 of each phase of the armature unit 210, and the selected coils 212 are excited with a predetermined current value. In this case, the vibration exciter cart 204 has a length equivalent to two magnetic pole periods of the magnetic flux density distribution of a pair of magnet arrays 224 when multiple magnet arrays 224 are arranged with a partition wall 226 between them. The selection of coils 212 and the excitation current value of the selected coils 212 can be determined based on the exact position of the magnet array 224 calculated based on the magnetic flux density detected by the Hall sensor 116 and the presence or absence of the vibration exciter cart 204 detected by the optical sensor 114.

[0113] Specifically, the output adjuster 140 corresponding to the Hall sensor 116 of each phase is set to output a signal indicating whether or not any of the three corresponding optical sensors 114 is detecting the vibration cart 204, and the excitation selector 146 outputs a signal indicating whether or not any of the optical sensors 114 at both ends of the coil 212 is detecting the vibration cart 204.

[0114] Furthermore, in the conveying device 100 of the first embodiment described above, the ratio of the number of field poles to the number of armature slots is 2 to 3, whereas in the vibration exciter 200, the ratio of the number of field poles to the number of armature slots is 4 to 3. As a result, in the vibration exciter 200, drive control similar to that of the conveying device 100 can be performed by simply switching the connections of the coils 212V and 212W and the Hall sensors 116V and 116W in the drive device 126.

[0115] Next, a description will be given of the operation of the vibration exciter 200. When the power is turned on, the drive unit 126 starts operating using three-phase AC power supplied from the power supply unit 136, and the vibration exciter cart 204 starts levitating and running. In the vibration exciter 200, as the vibration exciter cart 204 moves, a back electromotive force is generated in the coil 212 by the magnetic field generated by the magnet array 224, which is a dual Halbach array field magnet.

[0116] Here, we will explain the partition wall 226 provided in the field magnet section 220 in the vibration excitation device 200. The electromagnetic force acting between the magnet arrangement (Halbach field magnet arrangement) having a length that is an integer multiple of one magnetic pole period and the three-phase coils facing it can be made equal to the electromagnetic force obtained by cutting out an integer multiple of one magnetic pole period from the electromagnetic force acting between the three-phase coils 212 that are arranged facing each other in the magnetic flux density distribution that forms the Halbach array field magnet longer.

[0117] That is, in the vibration exciter 200, if the length of the magnet array 224 of the field magnet unit 220 is a natural number multiple (an integer multiple of 1 or greater) of the length Lm of one period of the shaft angle along the arrangement direction of the permanent magnets 222, a current similar to that flowing through the coils 212 near both ends in the movement direction of the field magnet unit 220 will flow as if the permanent magnets 222 were continuous. Also in the vibration exciter 200, the drive unit 126 detects the position of the vibration exciter cart 204 on the track 202 and the magnetic pole of the field magnet unit 220 using the optical sensor 114 and the Hall sensor 116, and supplies power to the coils 212 facing the vibration exciter cart 204 and the coils 212 before and after in the conveyance direction, thereby enabling effective power supply. As a result, the vibration exciter 200 can also achieve the same effects as the conveyance device 100 described above.

[0118] Furthermore, in the vibration excitation device 200, as in the conveyance device 100, the magnetic flux linkages of the two selectively excited coils 212 of each phase are sinusoidal (fundamental) components with the same amplitude but a phase difference of 120°, and no thrust ripple occurs in the thrust (electromagnetic force) acting between the magnet array 224 and the coils 212. Therefore, the vibration excitation device 200 can accelerate and decelerate the vibration vehicle 204 according to the target value, and the vibration excitation vehicle 204 can apply the desired vibration force to the vibration test specimen with a simple configuration. Furthermore, a smooth thrust acts on the vibration excitation vehicle 204, preventing vibration and noise. Therefore, the vibration excitation device 200 can be used as a configuration for transporting cargo, or as a conveyance device for transporting fragile items (such as cargo) to a destination without causing the cargo to collapse or break.

[0119] In the present embodiment, the electromagnetic device according to the present disclosure has been described using the conveyance device 100 of the first embodiment and the vibration device 200 of the second embodiment as examples. However, the present disclosure can be applied to any moving magnet type in which a field magnet part moves relative to an armature part, and can also be applied to a speaker or the like in which a diaphragm is vibrated by moving (vibrating) the field magnet part. Furthermore, since the electromagnetic device according to the present invention can prevent end effect, it can also be applied to various positioning devices, and by using it in a positioning device, it can achieve high-precision positioning.

[0120] As described above, the electromagnetic device according to the present disclosure can be modified in various ways. Furthermore, the periodic length of the magnetic poles in the magnet arrangement forming the Halbach array field magnet need only be an integer (positive integer) multiple of one period of the magnetic poles, and can be three or more periods. Furthermore, the permanent magnets constituting the array field magnet (Halbach array field magnet) were magnetized so that the north pole on the side where the magnetic field of the Halbach array field magnet is stronger was positioned at the center of the field magnet. However, the permanent magnets can be magnetized so that the north pole or south pole is positioned at any position in the field magnet. Furthermore, in the first and second embodiments, two armature coils were selected to be excited in each phase, but the number of armature coils selected can be any number greater than two. Furthermore, the arrangement of the permanent magnets is not limited to a linear shape, and can be an arc or other curved shape, and although the permanent magnets are rectangular, this does not limit the cross-sectional shape of the permanent magnets.

[0121] As described above, the present disclosure includes the following aspects: <1> An electromagnetic device including: a field section in a movable body that moves relatively in the longitudinal direction of a long fixed body, in which a number of divisions n is any one of three or more integers, and in which a plurality of permanent magnets are arranged so that the magnetization direction is changed in sequence by an angle obtained by dividing one electrical angle cycle corresponding to one magnetic pole cycle by the number of divisions n, and the length along the direction of movement of the movable body is a natural number multiple of the length of one electrical angle cycle; and an armature section that is provided on the fixed body, in which a plurality of sets of armature coils, one set for each phase, are arranged in the longitudinal direction of the fixed body within the movement range of the movable body, and power is supplied so that the same current flows through each of the armature coils of the same phase.

[0122] <2> An electromagnetic device including: a field section in which, in a movable body that moves relatively in the longitudinal direction of a long fixed body, a plurality of permanent magnets are arranged so that the magnetization direction is changed in sequence by an angle obtained by dividing one electrical angle cycle corresponding to one magnetic pole cycle by the division number n, where n is any one of three or more integers, and the length along the moving direction of the movable body is a natural number multiple of the length of one electrical angle cycle; an armature section that is provided on the fixed body and has a plurality of sets of armature coils, each set corresponding to the number of phases, arranged in the longitudinal direction of the fixed body within the moving range of the movable body; and a power supply section that supplies power to each of the armature coils in the armature section so that the same current flows between armature coils of the same phase when power is supplied to each of the armature coils of the armature section to move the movable body.

[0123] <3> The electromagnetic device according to <1>, including a power supply unit that supplies power to each of the armature coils so that the same current flows between the armature coils of the same phase when the moving body is moved.

[0124] <4> The electromagnetic device according to <2> or <3>, wherein the power supply unit supplies power to the armature coils in a range where magnetic flux from the field magnet unit of the moving body intersects with each other so that the same current flows through each of the armature coils of the same phase.

[0125] <5> The electromagnetic device according to any one of <2> to <4>, wherein the power supply unit supplies power to the armature coils of the same phase within a range of a length corresponding to half a magnetic pole period from each of both ends of the arrangement of the permanent magnets, so that the same current flows through each of the armature coils of the same phase.

[0126] <6> The electromagnetic device according to <4> or <5>, further comprising: a detection means provided on the fixed body opposite the field magnet section and configured to detect magnetic flux and detect an arrangement of the permanent magnets; and the power supply section supplies power to the armature coil in accordance with a detection result of the detection means.

[0127] <7> The electromagnetic device according to any one of <1> to <6>, wherein a length Lc of an arrangement of one set of the armature coils is a natural number multiple of a length Lm of one period of the magnetic poles of the permanent magnet.

[0128] <8> The electromagnetic device according to any one of <1> to <6>, wherein the length of the arrangement of the armature coils in the armature section is a natural number multiple of the length Lc of the arrangement of one set of the armature coils.

[0129] <9> The electromagnetic device of any one of <1> to <8>, wherein the field magnet section includes a first magnet arrangement and a second magnet arrangement, each of which has the plurality of permanent magnets arranged therein, and the first magnet arrangement and the second magnet arrangement are opposed to each other across the armature coil so that magnetic fields formed by the first magnet arrangement and the second magnet arrangement are reinforced by each other.

[0130] <10> The electromagnetic device of any one of <1> to <8>, wherein a ferromagnetic material is arranged in the armature portion in an arrangement range of the plurality of armature coils on the opposite side of the armature coils from the field portion.

[0131] The disclosure of Japanese Patent Application No. 2022-087258 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. a field magnet section in which a movable body that is moved relatively in the longitudinal direction of a long fixed body has a length that is a natural number multiple of the length of one electrical angle cycle along the moving direction of the movable body, the magnetization direction being changed in sequence by an angle obtained by dividing one electrical angle cycle corresponding to one magnetic pole cycle by the division number n, where n is any one of integers equal to or greater than 3, and a plurality of permanent magnets are arranged such that the magnetization direction is the same at both ends; an armature section provided on the fixed body, in which a plurality of sets of armature coils, each set corresponding to the number of phases, are arranged in the longitudinal direction of the fixed body within a moving range of the movable body, and power is supplied so that the same current flows through each of the armature coils of the same phase; wherein the cross-sectional shapes of the permanent magnets in the field portion when cut along the arrangement direction of the permanent magnets are the same for the permanent magnets in a middle portion excluding both ends in the arrangement direction, and the cross-sectional shapes of the permanent magnets at both ends in the arrangement direction when connected together are the same as the cross-sectional shapes of each of the permanent magnets in the middle portion.

2. a field magnet section in which a movable body that is moved relatively in the longitudinal direction of a long fixed body has a length that is a natural number multiple of the length of one electrical angle cycle along the moving direction of the movable body, the field magnet section having a plurality of permanent magnets arranged such that the magnetization direction is changed in sequence by an angle obtained by dividing one electrical angle cycle corresponding to one magnetic pole cycle by the division number n, where n is any one of integers equal to or greater than 3, and the magnetization direction is the same at both ends; an armature section provided on the fixed body, in which a plurality of sets of armature coils, each set corresponding to the number of phases, are arranged in a longitudinal direction of the fixed body within a moving range of the movable body; a power supply unit that supplies power to each of the armature coils of the armature unit so that the same current flows between the armature coils of the same phase when the moving body is moved by supplying power to each of the armature coils of the armature unit; wherein the cross-sectional shapes of the permanent magnets in the field portion when cut along the arrangement direction of the permanent magnets are the same for the permanent magnets in a middle portion excluding both ends in the arrangement direction, and the cross-sectional shapes of the permanent magnets at both ends in the arrangement direction when connected together are the same as the cross-sectional shapes of each of the permanent magnets in the middle portion.

3. 2. The electromagnetic device according to claim 1, further comprising a power supply section for supplying power to each of said armature coils so that the same current flows between said armature coils of the same phase when said moving body is moved.

4. 3. The electromagnetic device according to claim 2, wherein the power supply unit supplies power to the armature coils in a range where magnetic flux from the field magnet unit of the moving body is linked, such that the same current flows through each of the armature coils of the same phase.

5. 3. The electromagnetic device according to claim 2, wherein the power supply unit supplies power to the armature coils of the same phase within a range of a length of half a magnetic pole period from each of both ends of the array of permanent magnets such that the same current flows through each of the armature coils of the same phase.

6. a detection means provided on the fixed body facing the field magnet portion, for detecting magnetic flux and detecting an arrangement of the permanent magnets; 5. The electromagnetic device according to claim 4, wherein the power supply section supplies power to the armature coil in response to a detection result of the detection means.

7. 2. The electromagnetic device according to claim 1, wherein a length Lc of an arrangement of one set of said armature coils is a natural number multiple of a length Lm of one period of said magnetic poles of said permanent magnet.

8. 2. The electromagnetic device according to claim 1, wherein a length of the arrangement of the armature coils in the armature portion is a natural number multiple of a length Lc of one set of the arrangement of the armature coils.

9. 2. The electromagnetic device according to claim 1, wherein the field magnet section includes a first magnet arrangement and a second magnet arrangement, each of which has the plurality of permanent magnets arranged therein, and the first magnet arrangement and the second magnet arrangement are opposed to each other across the armature coil so that the magnetic fields formed by the first magnet arrangement and the second magnet arrangement reinforce each other.

10. 2. The electromagnetic device according to claim 1, wherein a ferromagnetic material is arranged in the armature portion on the opposite side of the armature coils to the field portion, in a range in which the plurality of armature coils are arranged.