Three-phase coil structure and linear motor

Abstract

To provide a three-phase coil structure and a linear motor capable of downsizing while suppressing a reduction in thrust.SOLUTION: In a three-phase coil structure 30 including a two-phase coil set 32 including a plurality of rectangular air-core coils of the same size that are arranged side by side in the same plane, a one-phase coil set 31 including two air-core coils of different lengths arranged so as to straddle adjacent long sides 321 of the two-phase coil set 32 is provided, and the two air-core coils are a large air-core coil 31B bent at both ends and a small air-core coil 31A that is flat.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a three-phase coil structure and a linear motor. [Background technology]

[0002] In recent years, linear motors using flat air-core coils have become popular. For example, Patent Document 1 discloses a linear motor in which the air-core coils for each phase are of two types, large and small, and the end of the air-core coil for one phase is bent and overlapped with the air-core coil for the other phase, thereby reducing the thickness of the three-phase coil structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5508362 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, to prevent differences in impedance and thrust between the air core coils of one phase and the air core coils of the other phase, two types of air core coils, large and small, are provided for all phases, and they have the same number of turns. As a result, the linear motor of Patent Document 1 does not achieve good efficiency performance relative to the structural area of ​​the air core coils, due to factors such as a decrease in thrust caused by a decrease in linkage length.

[0005] The present invention has been made in view of the above circumstances, and its object is to provide a three-phase coil structure and a linear motor that can be made compact while suppressing a decrease in thrust force. [Means for solving the problem]

[0006] The three-phase coil structure of the present invention is a three-phase coil structure comprising a two-phase coil set including a plurality of rectangular air core coils of the same dimensions arranged side by side in the same plane, and a one-phase coil set including two air core coils of different lengths arranged so as to straddle adjacent long sides of the two-phase coil set, the two air core coils being a large air core coil bent at both ends and a flat small air core coil.

[0007] In the present invention, the large air core coils and the small air core coils having different lengths and shapes are appropriately combined and arranged to make the three-phase coil structure compact.

[0008] In the three-phase coil structure of the present invention, the thickness of each of the large air core coil and the small air core coil is half that of the two-phase coil set, and the combined thickness of the one-phase coil set and the two-phase coil set is thinner than the sum of the thicknesses of the large air core coil, the small air core coil, and the two-phase coil set.

[0009] According to the present invention, the three-phase coil structure can be made compact.

[0010] In the three-phase coil structure according to the present invention, the number of turns of at least one of the large air core coil and the small air core coil is greater than the number of turns of the air core coil of the two-phase coil set.

[0011] In the present invention, since the length of the small air-core coil is shorter than that of the large air-core coil, it is possible to compactify the three-phase coil structure while preventing performance degradation such as a decrease in thrust due to a decrease in linkage length by making the number of turns of at least one of the large air-core coil and the small air-core coil greater than that of the air-core coil of the two-phase coil set.

[0012] In the three-phase coil structure of the present invention, both ends of the large air core coil are bent in a crank shape to one side in the axial direction of the large air core coil, the small air core coil is arranged on the same axis as the large air core coil on the one side of the large air core coil, and the other surfaces of the short sides of the large air core coil are in contact with the ends of the air core coils of the two-phase coil set.

[0013] In the present invention, both ends of the large air-core coil are bent in a crank shape to one side in the axial direction, the small air-core coil is arranged on one side of the large air-core coil, and the short sides of the large air-core coil overlap with the ends of the air-core coils of the two-phase coil set, thereby making it possible to make the three-phase coil structure more compact.

[0014] In the three-phase coil structure of the present invention, the length of the large air core coil is equal to that of the air core coil of the two-phase coil set, and the length of the small air core coil is longer than the length of the flat portion of the long side of the large air core coil and shorter than the distance between the two short side portions of the large air core coil.

[0015] In the present invention, the length of the small air-core coil is longer than the length of the flat portion of the long side of the large air-core coil and shorter than the distance between the two short side portions of the large air-core coil, thereby making it possible to make the three-phase coil structure more compact.

[0016] In the three-phase coil structure according to the present invention, one lead wire of the large air core coil and the small air core coil is arranged on the inner circumferential side, and the other lead wire is arranged on the outer circumferential side.

[0017] In the present invention, the large air-core coil and the small air-core coil are wound by simple winding, with one lead wire being arranged on the inner circumference side and the other lead wire being arranged on the outer circumference side, which simplifies the manufacturing process.

[0018] In the three-phase coil structure according to the present invention, a gap is formed between the long side of the large air core coil and the long side of the small air core coil, through which the inner lead wire of the large air core coil passes.

[0019] In the present invention, a gap is formed between the long side of the large air core coil and the long side of the small air core coil, so that the lead wire on the inner side of the large air core coil is taken out to the outer side through the gap and connected to the lead wire of the small air core coil.

[0020] The three-phase coil structure according to the present invention is formed by stacking two-phase coil set pairs each consisting of two two-phase coil sets arranged side by side in the same plane so as to be adjacent to each other, and one-phase coil sets are provided on both sides of the stacked two-phase coil set pair in the stacking direction, and the open-core coils of each one-phase coil set are bent in opposite directions at both ends.

[0021] In the present invention, two two-phase coil set pairs are stacked, and the one-phase coil sets are provided on both sides of the stacked two-phase coil set pairs in the stacking direction, and the length of the small air core coil is shorter than the length of the large air core coil, so that the three-phase coil structure can be made compact.

[0022] The linear motor of the present invention is a linear motor comprising a pair of yoke plates arranged opposite each other and a row of magnets provided on the inner surface of each yoke plate, in which any one of the three-phase coil structures described above is interposed between the row of magnets on one yoke plate and the row of magnets on the other yoke plate.

[0023] In the present invention, in any of the above three-phase coil structures, both ends of the large air core coil are bent in a crank shape toward one side in the axial direction, and a flat small air core coil is arranged on that side of the large air core coil, so that the three-phase coil structure can be easily positioned or removed between the magnet row of one yoke plate and the magnet row of the other yoke plate.

[0024] In the linear motor of the present invention, each yoke plate is rectangular, the pair of yoke plates are connected only at corresponding long sides, each magnet extends from the long side of each yoke plate toward the opposing side opposite the long side, and the length direction of each air-core coil of the three-phase coil structure coincides with the length direction of the magnet.

[0025] In the present invention, each magnet extends from one long side of each yoke plate toward the opposite side opposite to the one long side, and the length direction of each air-core coil of the three-phase coil structure coincides with the length direction of the magnet, so that a thrust acts on the three-phase coil structure in a direction intersecting the length direction, i.e., along the one long side. Therefore, by connecting a pair of yoke plates together at their short sides, the travel distance of the three-phase coil structure can be extended.

[0026] In the linear motor according to the present invention, the length of each magnet is longer than the length of the flat portion of the long side of the air-core coil.

[0027] In the present invention, the length of each magnet is longer than the length of the flat portion of the long side of the air-core coil, so the thrust can be made larger than when the length of each magnet is the same as the length of the flat portion of the long side.

[0028] In the linear motor according to the present invention, the three-phase coil structures are arranged in parallel in the direction in which the magnets are arranged so that the one-phase coil sets are arranged in the order of V-phase, W-phase, and U-phase.

[0029] In the present invention, when a plurality of the three-phase coil structures are arranged in parallel, the one-phase coil sets are arranged in the order of V phase, W phase, and U phase. For example, when there are three or more three-phase coil structures, the one-phase coil sets are arranged in parallel so that the order of V phase, W phase, and U phase is repeated. [Effects of the Invention]

[0030] According to the present invention, it is possible to provide a three-phase coil structure and a linear motor that can be made compact while suppressing a decrease in thrust. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a perspective view showing the appearance of a linear motor according to an embodiment of the present invention; [Figure 2] 1 is a plan view of a linear motor according to an embodiment of the present invention; [Figure 3] FIG. 2 is a schematic cross-sectional view of the linear motor taken along line III-III in FIG. [Figure 4] FIG. 2 is a perspective view showing a mover of the linear motor of the present embodiment. [Figure 5] FIG. 2 is a perspective view showing a three-phase coil structure of the linear motor of the present embodiment. [Figure 6] FIG. 2 is a front view showing a three-phase coil structure of the linear motor of the present embodiment. [Figure 7] FIG. 7 is a view taken along line VII-VII in FIG. 6. [Figure 8] FIG. 2 is a perspective view showing a two-phase coil set of the linear motor of the present embodiment. [Figure 9] FIG. 2 is a perspective view showing a one-phase coil set of the linear motor of the present embodiment. [Figure 10] FIG. 6 is a cross-sectional view taken along line XX in FIG. 5. [Figure 11] 10A and 10B are diagrams illustrating modified examples of the mover of the linear motor of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, a three-phase coil structure and a linear motor according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0033] FIG. 1 is a perspective view showing the appearance of a linear motor 100 according to an embodiment of the present invention, and FIG. 2 is a plan view of the linear motor 100 according to an embodiment of the present invention. The linear motor 100 is, for example, a moving coil type linear motor, and includes a stator 10 and a mover 20. The mover 20 is connected to a power supply (not shown).

[0034] Stator 10 has a pair of yoke plates 11 each having a rectangular, flat shape, and a connecting portion 12 that connects one end of yoke plates 11 together. Connecting portion 12 is provided on one long side of yoke plates 11. That is, connecting portion 12 is shaped like a strip with the same length as yoke plates 11, and connects one long side of one yoke plate 11 to one long side of the other yoke plate 11. Connecting portion 12 positions yoke plates 11 opposite each other at a predetermined distance, forming a gap between yoke plates 11. The pair of yoke plates 11 are open on the other three sides except for the one long side.

[0035] A mover 20 is interposed in the gap between the pair of yoke plates 11. The mover 20 includes an interposed portion 40 in the shape of a thick rectangular plate located between the pair of yoke plates 11, and a holding portion 21 that holds one end of the interposed portion 40 in the longitudinal direction. The mover 20 is movable in the opposing directions of the two short sides of the yoke plate 11 (the directions of the arrows in FIG. 2). That is, the arrows in FIG. 2 indicate the movement direction of the mover 20.

[0036] FIG. 3 is a schematic cross-sectional view of the linear motor 100 taken along line III-III in FIG. As described above, each yoke plate 11 has a rectangular flat plate shape and is made of a magnetic material such as iron. The connecting portion 12 is also made of a magnetic material such as iron, just like the yoke plates 11. The pair of yoke plates 11 and the connecting portion 12 are, for example, integrally formed.

[0037] A magnet unit 13 (array of magnets) is attached to the inner surface of each yoke plate 11. That is, the magnet unit 13 is disposed between the yoke plate 11 and the mover 20. In other words, the mover 20 is interposed between a pair of opposing magnet units 13.

[0038] Each magnet unit 13 has a plurality of permanent magnets 131. Each permanent magnet 131 has a rectangular bar shape extending in the width direction of the yoke plate 11, and the plurality of permanent magnets 131 are arranged side by side at equal intervals in the direction of movement of the mover 20. That is, each permanent magnet 131 extends from the vicinity of one long side of each yoke plate 11 to the vicinity of the other long side (opposing side) opposite the one long side, and the plurality of permanent magnets 131 are arranged side by side in the width direction of the permanent magnets 131. Furthermore, each permanent magnet 131 of one yoke plate 11 faces the permanent magnet 131 of the other yoke plate 11 in the thickness direction.

[0039] The pair of magnet units 13 forms an alternating magnetic field. More specifically, the magnetic poles of each permanent magnet 131 face in the opposing direction of the pair of magnet units 13, and in the opposing direction, the magnetic poles of the permanent magnets 131 are opposite to each other, and the magnetic poles of adjacent permanent magnets 131 are also opposite to each other (see FIG. 2).

[0040] A groove 121 is formed in the center in the width direction on the inner surface of the connecting portion 12. The groove 121 is formed along the length direction of the connecting portion 12 and is open to the outside from both end faces. In other words, the groove 121 is formed at a position corresponding to the other end of the interposition portion 40 of the mover 20, and the other end of the interposition portion 40 is partially housed within the groove 121.

[0041] 4 is a perspective view showing the mover 20 of the linear motor 100 of this embodiment. For convenience, the holding portion 21 is shown by a broken line in FIG. As described above, the intervening portion 40 of the mover 20 is interposed between a pair of magnet units 13 (see FIG. 3). The intervening portion 40 includes a three-phase coil structure 30 made up of a plurality of stacked air-core coils. Specifically, the intervening portion 40 is formed by molding the three-phase coil structure 30 using a molding material 50 such as epoxy resin or glass fiber reinforced engineering plastic (PPS). The intervening portion 40 has a rectangular thick plate shape corresponding to the shape of the three-phase coil structure 30. That is, the stacking direction of the air-core coils of the three-phase coil structure 30 is the thickness direction of the intervening portion 40, the length direction of the three-phase coil structure 30 is the length direction of the intervening portion 40, and the width direction of the three-phase coil structure 30 is the width direction of the intervening portion 40. The thickness of the intervening portion 40 is thinner than the gap between the magnet units 13.

[0042] A substantially rectangular parallelepiped holding portion 21 is attached to one longitudinal end of the interposition portion 40. The holding portion 21 has a height substantially equal to the width of the interposition portion 40, and a thickness greater than the distance between the magnet units 13. The holding portion 21 is held by a linear guide (not shown) so as to be movable in the direction of the arrow in FIG. 2.

[0043] 3, when the intervening portion 40 is interposed between the magnet units 13, the holding portion 21 does not get caught on the permanent magnet 131 on the other long side of the yoke plate 11, and the intervening portion 40 can maintain a state of hanging from the linear guide without coming into contact with any of the magnet units 13 or the bottom of the groove 121. In this case, the length LM (see FIG. 3) of each permanent magnet 131 is longer than the representative linkage length Lu (see FIG. 9) of the air-core coil 31B of the three-phase coil structure 30, which will be described later, and is approximately equal to the neutral line length Lu0 (see FIG. 8) of the two-phase coil set 32.

[0044] FIG. 5 is a perspective view showing the three-phase coil structure 30 of the linear motor 100 of this embodiment, FIG. 6 is a front view showing the three-phase coil structure 30 of the linear motor 100 of this embodiment, and FIG. 7 is a view taken along the arrow VII-VII in FIG. 6.

[0045] The three-phase coil structure 30 includes a one-phase coil set 31 for the V phase and a two-phase coil set 32 ​​for the U and W phases. The one-phase coil set 31 and the two-phase coil set 32 ​​are both configured from approximately rectangular air-core coils. For convenience, the lead wires of the one-phase coil set 31 and the two-phase coil set 32 ​​are not shown in Figures 5 to 7.

[0046] Each two-phase coil set 32 ​​includes two air-core coils arranged coaxially and having the same length and width dimensions. The two two-phase coil sets 32 for the U and W phases are arranged so that their respective axes are parallel. That is, the two two-phase coil sets 32 are arranged side by side in the same plane, with the long side of the air-core coil of one two-phase coil set 32 ​​in contact with the long side of the air-core coil of the other two-phase coil set 32, forming an approximate shape of the number "8." Hereinafter, these two two-phase coil sets 32 are also referred to as a two-phase coil set pair 32P.

[0047] The three-phase coil structure 30 has two two-phase coil set pairs 32P, and the two two-phase coil set pairs 32P are stacked on the same axis. In other words, in the three-phase coil structure 30, each two-phase coil set 32 ​​of one two-phase coil set pair 32P is further stacked with another two-phase coil set 32. The two-phase coil sets 32 of the two-phase coil set pair 32P have the same shape, and the following description will focus on only one two-phase coil set 32.

[0048] The one-phase coil set 31 is arranged to straddle adjacent long sides of the two-phase coil set pair 32P and includes two air core coils of different sizes. Hereinafter, the smaller air core coil will be referred to as the small air core coil 31A, and the larger air core coil will be referred to as the large air core coil 31B. The small air core coil 31A has a smaller longitudinal dimension than the large air core coil 31B, but the dimensions are the same in the width direction. The length of the small air core coil 31A is shorter than the distance between both ends of the large air core coil 31B. The small air core coil 31A and the large air core coil 31B are arranged on the same axis. The axial direction of the one-phase coil set 31 is parallel to the axial direction of each two-phase coil set 32. In the three-phase coil structure 30, one-phase coil sets 31 are arranged on both sides of the two stacked two-phase coil set pairs 32P in the stacking direction.

[0049] FIG. 8 is a perspective view showing the two-phase coil set 32 ​​of the linear motor 100 of this embodiment. Each two-phase coil set 32 ​​is a hollow rectangle when viewed from the front, and includes two long sides 321, 322 and two short sides 323, 324. In each two-phase coil set 32, the two long sides 321, 322 have the same widthwise dimension and are spaced apart by a distance equivalent to the sum of the widthwise dimensions of the long sides 321, 322. The long side of the long side 321 of one two-phase coil set 32 ​​is adjacent to the long side 321 of the other two-phase coil set 32 ​​(see FIGS. 5 and 6).

[0050] As described above, the two-phase coil set 32 ​​is flat and includes two rectangular air-core coils 300 arranged on the same axis. That is, the long sides 321, 322 and the short sides 323, 324 of the two-phase coil set 32 ​​are arranged on the same plane.

[0051] Each air-core coil 300 is formed by winding, for example, a strip-shaped 1.1 x 0.54 mm rectangular wire conductor, 15 turns per layer in a direction perpendicular to the axial direction (hereinafter referred to as the winding direction). The rectangular wires are wound so that they overlap in the thickness direction (of the rectangular wire). That is, the air-core coil 300 has two layers (alpha winding) in the axial direction and multiple layers in the winding direction, with both axial end faces being approximately flat. The rectangular wire is wound with a thermosetting resin adhesive, such as epoxy resin, applied to its outer surface. The adhesive cures at room temperature or by heating. This maintains the shape of the air-core coil 300, and in the two-phase coil set 32, the stacked air-core coils 300 are fixed together in the axial direction. For convenience, Figures 5, 6, and 8 show only the axial end faces (multi-layered coil) of the air-core coil 300.

[0052] 8, the dashed dotted line indicates the neutral line of the two-phase coil set 32. The neutral line is a line connecting the center points in the winding direction of the two-phase coil set 32. Furthermore, the symbol Lu0 in FIG. 8 indicates the distance (neutral line length) between the neutral lines of the short side portions 323, 324. As described above, the length LM (see FIG. 3) of each permanent magnet 131 of the magnet unit 13 is approximately equal to the neutral line length Lu0.

[0053] The two-phase coil set 32 ​​is formed by so-called alpha winding, in which the two air-core coils 300 are stacked in the axial direction so that the winding directions are the same. Therefore, in the two-phase coil set 32, the lead wire 325 which is the winding start and the lead wire 326 which is the winding end are both arranged on the outer periphery of the two-phase coil set 32. In other words, the two-phase coil set 32 ​​is a single coil wound with 30 turns (30 turns) using alpha winding.

[0054] Fig. 9 is a perspective view showing the one-phase coil set 31 of the linear motor 100 of this embodiment. For convenience, the small air-core coil 31A and the large air-core coil 31B are shown separately in Fig. 9. Note that in Fig. 9, the flow of current is indicated by a dashed line. Like the two-phase coil set 32, both the small air-core coil 31A and the large air-core coil 31B are hollow rectangular in front view. The small air-core coil 31A is disposed on one side in the axial direction of the large air-core coil 31B. The small air-core coil 31A has two long sides 311A, 312A and two short sides 313A, 314A. The large air-core coil 31B has two long sides 311B, 312B and two short sides 313B, 314B (ends).

[0055] The large air core coil 31B is bent into a crank shape by pressing both ends of the long sides 311B, 312B. As a result, bent portions 318B are formed on both ends of the two long sides 311B, 312B of the large air core coil 31B. After such pressing, the length of the large air core coil 31B in the longitudinal direction is the same as that of the air core coil 300 of the two-phase coil set 32.

[0056] In addition, in large air core coil 31B, the distance between long sides 311B, 312B and short sides 313B, 314B is the same as the thickness of small air core coil 31A or air core coil 300 (see FIG. 10).

[0057] Bent portions 318B of air core coil 31B are bent toward the one side in the axial direction at a bend angle of 30° to 44.5°. That is, each bent portion 318B is formed at an angle in the range of 30° to 44.5° relative to a direction perpendicular to the axial direction of air core coil 31B. If the bend angle of bent portions 318B is below the lower limit of this range, the proportion of bent portions 318B in long sides 311B, 312B increases, and the flat portions become narrower, resulting in a decrease in thrust. Furthermore, if the bend angle of bent portions 318B exceeds 44.5°, defects such as scratches may occur in air core coil 31B during press working.

[0058] In the small air-core coil 31A, the two long sides 311A, 312A have the same widthwise dimension and are formed apart a distance equivalent to the sum of the widthwise dimensions of the long sides 311A, 312A. In the large air-core coil 31B, the two long sides 311B, 312B have the same widthwise dimension and are formed apart a distance equivalent to the sum of the widthwise dimensions of the long sides 311B, 312B. That is, in the axial direction, the long sides 311A, 312A of the small air-core coil 31A face the long sides 311B, 312B of the large air-core coil 31B, respectively (see FIG. 5).

[0059] As described above, the small air-core coil 31A and the large air-core coil 31B are arranged on the same axis, and the small air-core coil 31A has a smaller length dimension than the large air-core coil 31B, but the width dimension is the same.

[0060] The length of the small air-core coil 31A is longer than the length Lu (the representative interlinkage length of the three-phase coil structure 30) of the flattened portions (excluding the bent portions 318B at both ends) of the long sides 311B, 312B of the large air-core coil 31B, but shorter than the distance between the short sides 313B, 314B of the large air-core coil 31B. The long sides 311A, 312A of the small air-core coil 31A can be longer than the length Lu as long as they do not interfere with the bent portions 318B and short sides 313B, 314B of the large air-core coil 31B. The small air-core coil 31A does not contact the short sides 313B, 314B of the large air-core coil 31B. The thickness of the small air-core coil 31A and the large air-core coil 31B is equal to the thickness of the air-core coil 300 of the two-phase coil set 32. The length of the long sides 311A, 312A of the small air-core coil 31A may be shortened within a range that allows balance with the impedance of the other two-phase coil sets 32 to be maintained.

[0061] Like the air core coil 300 of the two-phase coil set 32, the small air core coil 31A and the large air core coil 31B are formed by winding a flat wire conductor multiple times in a direction perpendicular to the axial direction. That is, the flat wires are wound so that they overlap each other in the thickness direction (of the flat wire). Therefore, the small air core coil 31A and the large air core coil 31B are single-layered in the axial direction and multi-layered in the direction perpendicular to the axial direction, and both end surfaces in the axial direction are approximately flat. For convenience, Figures 5, 6, and 9 show the axial end surfaces (multi-layered coils) of the small air core coil 31A and the large air core coil 31B simply.

[0062] The small air-core coil 31A is wound using a simple winding, and has a lead wire 315A at the start of the winding and a lead wire 316A at the end of the winding. The lead wire 315A is arranged on the inner periphery of the small air-core coil 31A, and the lead wire 316A is arranged on the outer periphery of the small air-core coil 31A.

[0063] Furthermore, the air-core coil 31B is wound by simple winding, and has a lead wire 315B which is the start of the winding and a lead wire 316B which is the end of the winding. The lead wire 315B is arranged on the inner periphery side of the air-core coil 31B, and the lead wire 316B is arranged on the outer periphery side of the air-core coil 31B.

[0064] FIG. 10 is a cross-sectional view taken along line XX in FIG. As described above, the three-phase coil structure 30 has two two-phase coil set pairs 32P stacked in the axial direction (arrow direction in FIG. 10), and one-phase coil sets 31 are arranged on both sides (first side and second side) of the two stacked two-phase coil set pairs 32P in the stacking direction (arrow direction in FIG. 10). In this case, the air-core coils 31B abut against each other in the axial direction.

[0065] For convenience of explanation, the following description will be given taking the first-phase coil set 31 and the two-phase coil set pair 32P arranged on the first side as an example. The one-phase coil set 31 and each two-phase coil set 32 ​​are arranged so that their axial and longitudinal directions are parallel, and the one-phase coil set 31 partially overlaps with the two-phase coil set pair 32P.

[0066] 6, the one-phase coil set 31 is stacked so as to straddle the long sides 321 of two adjacent two-phase coil sets 32. The two long sides 321 of the two-phase coil set pair 32P are interposed between the long sides 311A, 312A of the small air-core coil 31A and between the long sides 311B, 312B of the large air-core coil 31B.

[0067] Since both ends of the hollow core coil 31B are bent in the axial direction, the surfaces 317B, 319B of the short sides 313B, 314B facing the two-phase coil set 32 ​​abut against the short sides 323, 324 of the two-phase coil set 32 ​​(see Figure 7), while the long sides 311B, 312B do not abut against the long side 321 of the two-phase coil set 32 ​​and are positioned closer to the second side than the short sides 313B, 314B (see Figure 10).

[0068] In contrast, the small air-core coil 31A is flat and not bent, so its short sides 313A and 314A abut against the long side 321 of the two-phase coil set 32, and its long sides 311A ​​and 312A face the long sides 311B and 312B of the large air-core coil 31B. In other words, because both ends of the small air-core coil 31A are not bent, a gap 200 is formed between the long sides 311A ​​and 312A of the small air-core coil 31A and the long sides 311B and 312B of the large air-core coil 31B. Furthermore, small air-core coil 31A is arranged in the same plane as short sides 313B and 314B of large air-core coil 31B (see the dashed line in FIG. 7).

[0069] Through the gap 200, the lead wire 315B on the inner periphery side of the large air core coil 31B is led out to the outer periphery side of the large air core coil 31B and is connected to the lead wire 316A of the small air core coil 31A on the outer periphery side of the large air core coil 31B (or the small air core coil 31A). In Figure 10, the connection part N between the lead wire 315B of the large air core coil 31B and the lead wire 316A of the small air core coil 31A is shown by a black circle.

[0070] As described above, the thickness of the two-phase coil set 32 ​​is 2t. The thickness of the air core coil 300, the small air core coil 31A and the large air core coil 31B are the same thickness (t). Here, the total thickness of the two-phase coil set 32 ​​and the large air core coil 31B and small air core coil 31A is 4t, but the large air core coil 31B is curved at its end, and the large air core coil 31B and small air core coil 31A are arranged so as to straddle adjacent long side portions 321 of the two-phase coil set 32.Therefore, as shown in Figure 10, in the three-phase coil structure 30, one one-phase coil set 31 and two-phase coil set pair 32P on the first side have a thickness of 3t in the axial direction, and one one-phase coil set 31 and two-phase coil set pair 32P on the second side also have a thickness of 3t, so the three-phase coil structure 30 has an overall thickness of 6t. In other words, the thickness of each of the large air core coil 31B and the small air core coil 31A is half the thickness of the two-phase coil set 32, and the thickness of the assembled one-phase coil set 31 and two-phase coil set 32 ​​is 3 / 4 of the combined thickness of the large air core coil 31B, the small air core coil 31A and the two-phase coil set 32.

[0071] When the linear motor 100 having such a configuration is energized through the three-phase coil structure 30, a thrust force is generated in a direction (hereinafter referred to as the movement direction) that crosses the alternating magnetic field formed between the pair of magnet units 13 based on Fleming's left-hand rule, pushing the three-phase coil structure 30 in the movement direction, thereby moving the mover 20 (see the arrow in FIG. 2).

[0072] On the other hand, in the three-phase coil structure 30, the small air-core coil 31A has a smaller longitudinal dimension than the large air-core coil 31B, resulting in a reduced linkage length. Such a reduction in linkage length may result in a decrease in coil impedance and a decrease in thrust.

[0073] In contrast, the linear motor 100 of this embodiment addresses the above-mentioned problems of reduced coil impedance and reduced thrust by increasing the number of turns of the one-phase coil set 31. That is, in the linear motor 100 of this embodiment, the one-phase coil set 31 has a larger number of turns than the two-phase coil set 32.

[0074] In detail, since the one-phase coil set 31 has a small air-core coil 31A and a large air-core coil 31B, the number of turns of the small air-core coil 31A or the number of turns of the large air-core coil 31B may be greater than the number of turns of each air-core coil 300 of the two-phase coil set 32, and the number of turns of the small air-core coil 31A and the number of turns of the large air-core coil 31B may both be greater than the number of turns of the air-core coil 300.

[0075] For example, if the number of turns of each air core coil 300 in the two-phase coil set 32 ​​is 15, the number of turns of the small air core coil 31A or the large air core coil 31B is 16 to 17. More specifically, it is desirable that the number of turns of the small air core coil 31A is 16, and the number of turns of the large air core coil 31B is 17. Also, the present invention is not limited to this. When considering changes in coil impedance, it is also effective to set the number of turns to 16 for both the small air-core coil 31A and the large air-core coil 31B.

[0076] As described above, in the linear motor 100 of this embodiment, the number of turns of the one-phase coil set 31 is greater than the number of turns of the two-phase coil set 32, so that the reduction in coil impedance and thrust can be compensated for.

[0077] In the three-phase coil structure 30 of this embodiment, a pair of adjacent two-phase coil sets 32 (two-phase coil set pairs 32P) are stacked in the axial direction, and a one-phase coil set 31 is provided on each side of the two stacked two-phase coil set pairs 32P in the axial direction, with both ends of the hollow core coil 31B of one one-phase coil set 31 bent in the opposite direction to both ends of the other one-phase coil set 31 (see Figures 5 and 7).

[0078] As described above, the three-phase coil structure 30 has an overall thickness of 6t. Because the first-phase coil set 31 is made up of the small air-core coil 31A and the large air-core coil 31B, and the second-phase coil set 32 ​​is made up of two air-core coils 300, the overall thickness of the three-phase coil structure 30 is kept to 6t despite the fact that eight air-core coils are stacked, making the three-phase coil structure 30 compact.

[0079] Furthermore, in the linear motor 100 of this embodiment, as described above, the flat small air-core coil 31A in the three-phase coil structure 30 is arranged in the same plane as the short side portions 313B, 314B of the large air-core coil 31B, the thickness of the interposition portion 40 (three-phase coil structure 30) is thinner than the gap between the magnet units 13, and the gap in the stator 10 (pair of yoke plates 11) is formed on three sides other than the one long side. Therefore, the mover 20 (interposition portion 40) can be inserted into the stator 10 from any of these three sides, increasing the degree of freedom in operation.

[0080] Furthermore, in the linear motor 100 of this embodiment, as described above, both short sides of the stator 10 (the pair of yoke plates 11) related to the movement direction of the mover 20 are open. Therefore, by arranging multiple stators 10 in series so that the short sides of the stators 10 face each other, the movement distance of the mover 20 can be extended as needed.

[0081] It is generally known that the magnetic flux density distribution for an air-core coil decreases by about 10% at both ends of the coil, and it is therefore efficient and desirable to set the length of the permanent magnet to the neutral line length of the air-core coil.

[0082] In contrast, in the linear motor 100 of this embodiment, although both ends of the large air-core coil 31B are bent, by making the small air-core coil 31A flat, the small air-core coil 31A is arranged in the same plane as the short sides 313B, 314B of the large air-core coil 31B. Therefore, as described above, the length LM of each permanent magnet 131 is made equal to the neutral line length Lu0, which efficiently increases the thrust.

[0083] In linear motor 100 of this embodiment, small air-core coil 31A has a shape with both ends flattened, so there is no need to bend both ends like with large air-core coil 31B, and no press machine is required for bending. Furthermore, since there is no crank portion (bent portion 318B) like in large air-core coil 31B, there is no decrease in efficiency with respect to magnetic flux at the crank portion, and the entire length of small air-core coil 31A can be fully utilized.

[0084] In the linear motor 100 of this embodiment, a gap 200 is formed between the long sides 311A, 312A of the small air-core coil 31A and the long sides 311B, 312B of the large air-core coil 31B, and the lead wire 315B on the inner side of the large air-core coil 31B is led out to the outer side of the large air-core coil 31B through the gap 200. In order to draw out the lead wire 315B on the inner periphery side of the air core coil 31B to the outside, the lead wire 315B must pass over the end face in the thickness direction of the air core coil 31B, which results in an increase in the thickness of the three-phase coil structure 30. In contrast, in the linear motor 100 of this embodiment, the lead wire 315B is drawn out to the outer periphery side of the air core coil 31B through the gap 200, so the three-phase coil structure 30 can be made more compact without increasing the thickness.

[0085] In this embodiment, a coil using rectangular wire has been described as an example, but the effects of the present invention can also be achieved with a coil using round wire. In the case of round wire, the two air-core coils (two-phase coil set 32) can be four layers (because the thickness direction is shorter than that of rectangular wire), in which case the large air-core coil 31B and the small air-core coil 31A can be either alpha wound or simply wound (two layers).

[0086] <Modification> Although the above description has been given taking an example where the mover 20 has one three-phase coil structure 30, the present invention is not limited to this. The mover 20 may be configured to have a plurality of three-phase coil structures 30. Below, a detailed description will be given taking an example where the mover 20 has three three-phase coil structures 30.

[0087] Fig. 11 is an illustrative diagram illustrating a modified example of the mover 20 of the linear motor 100 of this embodiment. For convenience, the holding portion 21 is not shown in Fig. 11. The mover 20 according to the modified example has three three-phase coil structures 30X, 30Y, and 30Z.

[0088] The three three-phase coil structures 30X, 30Y, 30Z are arranged side by side in this order with no gaps between them. The three three-phase coil structures 30X, 30Y, 30Z are arranged side by side in the width direction of each three-phase coil structure. The three three-phase coil structures 30X, 30Y, 30Z are integrated by molding using a molding material 50 to form an interposed portion 40. The interposed portion 40 has a rectangular plate shape with its length direction aligned with the direction in which the three three-phase coil structures 30X, 30Y, 30Z are arranged side by side.

[0089] The three-phase coil structure 30X includes a first-phase coil set 31X and a two-phase coil set 32X, with the first-phase coil set 31X including a small air-core coil 31AX and a large air-core coil 31BX. The three-phase coil structure 30Y includes a first-phase coil set 31Y and a two-phase coil set 32Y, with the first-phase coil set 31Y including a small air-core coil 31AY and a large air-core coil 31BY. The three-phase coil structure 30Z includes a first-phase coil set 31Z and a two-phase coil set 32Z, with the first-phase coil set 31Z including a small air-core coil 31AZ and a large air-core coil 31BZ. Each of the three-phase coil structures 30X, 30Y, and 30Z has the same configuration as the above-described three-phase coil structure 30, and therefore detailed description thereof will be omitted.

[0090] In the linear motor 100 according to the modified example, the one-phase coil set 31X of the three-phase coil structure 30X is for the V phase, the one-phase coil set 31Y of the three-phase coil structure 30Y is for the W phase, and the one-phase coil set 31Z of the three-phase coil structure 30Z is for the U phase. That is, the one-phase coil sets 31X, 31Y, and 31Z of the three-phase coil structures 30X, 30Y, and 30Z correspond to the V phase, W phase, and U phase, respectively.

[0091] It should be noted that the present invention is not limited to the above description, and the mover 20 may be configured to have two three-phase coil structures 30, or the mover 20 may be configured to have four or more three-phase coil structures 30.

[0092] In this way, when the mover 20 has multiple three-phase coil structures 30, the coil sets 31 for one phase of each three-phase coil structure 30 are repeatedly applied in the order of V phase, W phase, and U phase, respectively, along the parallel arrangement direction. For example, when the mover 20 has two three-phase coil structures 30, the one-phase coil sets 31 of each three-phase coil structure 30 are applied to the V phase and the W phase, respectively, along the juxtaposition direction of the three-phase coil structures 30. When the mover 20 has four or more three-phase coil structures 30, the one-phase coil sets 31 of each three-phase coil structure 30 are applied to the V phase, W phase, U phase, V phase, etc., along the juxtaposition direction of the three-phase coil structures 30.

[0093] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0094] 11 York board 12 Connecting part 13 Magnet unit 30 3-phase coil structure 31 1-phase coil set 31A small air core coil 31B Large hollow core coil 32 2-phase coil set 32P 2-phase coil set pair 100 Linear Motor 200 gap 300 air core coil 311A, 312A, 311B, 312B, 321, 322 Long side 313A, 314A, 313B, 314B, 323, 324 Short side 315A, 316A, 315B, 316B, 325, 326 Lead wire 317B side (other side) 318B Bent part 319B side (other side) 131 Permanent Magnets

Claims

1. A three-phase coil structure including a two-phase coil set including a plurality of rectangular air-core coils of the same dimensions arranged side by side in the same plane, It is equipped with a one-phase coil set including two air-core coils of different lengths, The two air-core coils are a large air-core coil bent at both ends, and a small air-core coil that is shorter in length than the large air-core coil and is flatter, The length of the large air-core coil is equal to that of the air-core coil of the two-phase coil set, the length of the small air-core coil is longer than the length of the flat portion of the long side of the large air-core coil and shorter than the distance between both short side portions of the large air-core coil; the large air core coil has both ends bent in a crank shape to one side in the axial direction of the large air core coil, and the flat portion is disposed so as to straddle adjacent long side portions of the two-phase coil set, the short side portions of the large air-core coils are in contact with the ends of the air-core coils of the two-phase coil set on the other side surfaces thereof, the small air-core coil is disposed on the same axis as the large air-core coil and on the one side of the flat portion of the large air-core coil; A three-phase coil structure in which the number of turns of at least one of the large air-core coil and the small air-core coil is greater than the number of turns of the air-core coil of the two-phase coil set.

2. the thickness of each of the large air-core coil and the small air-core coil is half that of the two-phase coil set; 2. The three-phase coil structure according to claim 1, wherein the combined thickness of the one-phase coil set and the two-phase coil set is thinner than the sum of the thicknesses of the large air core coil, the small air core coil, and the two-phase coil set.

3. 3. The three-phase coil structure according to claim 1, wherein one lead wire of the large air-core coil and the small air-core coil is arranged on the inner circumferential side and the other lead wire is arranged on the outer circumferential side.

4. 4. The three-phase coil structure according to claim 3, wherein a gap is formed between the long side of the large air-core coil and the long side of the small air-core coil, through which an inner lead wire of the large air-core coil passes.

5. A two-phase coil set pair is stacked, the two two-phase coil sets being arranged side by side in the same plane so as to be adjacent to each other, the one-phase coil sets are provided on both sides of the stacked two-phase coil set pair in the stacking direction, 5. The three-phase coil structure according to claim 1, wherein both ends of the hollow core coil of each one-phase coil set are bent in opposite directions.

6. A linear motor having a pair of yoke plates arranged opposite to each other and a row of magnets provided on the inner surface of each yoke plate, A linear motor, wherein the three-phase coil structure according to any one of claims 1 to 5 is interposed between a row of magnets on one yoke plate and a row of magnets on the other yoke plate.

7. Each yoke plate is rectangular, The pair of yoke plates are connected to each other only on corresponding long sides, Each magnet extends from the long side of each yoke plate toward an opposite side opposite to the long side, 7. The linear motor according to claim 6, wherein the length direction of each air-core coil of the three-phase coil structure coincides with the length direction of the magnet.

8. 8. The linear motor according to claim 6, wherein the length of each magnet is longer than the length of the flat portion of the long side of the air-core coil.

9. 9. The linear motor according to claim 6, wherein the plurality of three-phase coil structures are arranged in parallel in the direction in which the magnets are arranged so that the one-phase coil sets are arranged in the order of V phase, W phase, and U phase.

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