Coreless motor

Abstract

In order to improve motor characteristics, this coreless motor (100) is provided with: a rotary shaft (20); a coil (60) which is formed in a cylindrical shape by winding a conductor (61) and rotates integrally with the rotary shaft (20); and a cylindrical magnet (30) which is disposed inside the cylindrical shape of the coil (60). One winding of the coil (60) is formed in a hexagonal shape having parallel sections (62) which are parallel to an axial direction (center C direction) of the rotary shaft (20) and two oblique side portions (63, 64) which are inclined with respect to a surface orthogonal to the center C direction and connected to both ends of the parallel sections (62), wherein the oblique side portions (63, 64) are formed in a curved shape protruding from the inner side toward the outer side of the one winding of the coil (60), and a tangential angle (θ) between a tangential line of the oblique side portion (63) drawn from a vertex where two adjoining oblique side portions (63, 63) in the one winding of the coil (60) are connected together at one end and a surface orthogonal to the rotary shaft (20) is set in a range of 15 [degrees] to 50 [degrees].

Description

Technical Field

[0001] The present invention relates to a coreless motor.

Background Art

[0002] A coreless motor has no iron core that serves as a core for the coil, and forms a rotor only with windings. As a winding method of the conducting wire forming the coil, there is one formed in a hexagonal shape (turtle shell shape). In this turtle shell-shaped winding method, for example, while winding the conducting wire in the circumferential direction on the outer peripheral surface of a hexagonal column, the conducting wire is shifted little by little in the axial direction of the hexagonal column to form a hexagonal spiral coil element, and by pulling out the hexagonal column in the axial direction from the coil element, a coil element formed in a spiral shape of the hexagonal column only with the conducting wire is obtained.

[0003] Then, the sides corresponding to the opposing surfaces of the hexagonal column are flattened in a planar shape by moving them in opposite directions along the axial direction of the hexagonal column, and a plurality of the obtained planar coil elements are connected and the axial end portions are connected to each other to form a cylindrical coil.

[0004] The coil formed in a cylindrical shape has, on both the outer surface side and the inner surface side, a parallel portion where the conducting wire is parallel to the axis of the cylinder, and two hypotenuse portions that are connected to the parallel portion and inclined with respect to the surface orthogonal to the axis of the cylinder. Here, there has also been proposed a structure in which the hypotenuse portion is formed into an arc-shaped curve to increase the magnetic flux passing through the hypotenuse portion (see, for example, Patent Document 1).

[0005] In addition, even in a coil having only hypotenuse portions without a parallel portion, with the winding method of the conducting wire being a quadrilateral instead of a hexagon (turtle shell shape), there has been proposed a structure in which the hypotenuse portion is formed into an arc shape (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

[0007] The coils described in the aforementioned prior art documents increase the magnetic flux passing through them by forming the hypotenuse in a curved shape, but they do not specifically define a practical shape for the curve of the hypotenuse.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a coreless motor that specifically defines a practical shape for the curve of the hypotenuse portion of a hexagonal (tortoise shell) shaped coil in order to improve the characteristics of the motor. [Means for solving the problem]

[0009] The present invention relates to a coreless motor comprising a rotating shaft, a coil formed by winding a wire into a cylindrical shape and rotating integrally with the rotating shaft, and a cylindrical magnet disposed inside or outside the cylindrical shape of the coil, wherein one turn of the coil is formed in a hexagonal shape having a parallel portion in which the wire extends parallel to the axial direction of the rotating shaft, and two slanted portions connected to both ends of the parallel portion and inclined with respect to a plane perpendicular to the axial direction, the slanted portions are formed in a curved shape that is convex from the inside to the outside of the one turn of the coil, and the tangent angle, which is the angle between the tangent to the slanted portion drawn from the vertex connecting the two adjacent ends of the slanted portions in the one turn of the coil and the plane perpendicular to the rotating shaft, is set in the range of 15 degrees or more and 50 degrees or less. [Effects of the Invention]

[0010] The coreless motor according to the present invention exhibits excellent motor characteristics because it specifically defines the practical shape of the curved hypotenuse of the hexagonal (tortoise-shell) shaped coil. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing a longitudinal section of the coreless motor of Embodiment 1, including the center C of the rotation axis. [Figure 2] This is a side view showing the coil of the coreless motor shown in Figure 1. [Figure 3A] Figure 2 is a schematic diagram showing process 1 for manufacturing the coil shown. [Figure 3B] Figure 2 is a schematic diagram showing process 2 for manufacturing the coil shown. [Figure 3C] Figure 2 is a schematic diagram showing step 3 of the manufacturing process for the coil shown. [Figure 4] This diagram schematically shows the positional relationship between the magnet and the hexagonal shape of one turn of the coil. [Figure 5] This is a schematic diagram showing the tangent angle θ, which is the angle between the tangent to the hypotenuse of a coil and the plane perpendicular to the parallel part. [Figure 6] This is a schematic diagram showing the relationship between the magnetic pole pitch and coil pitch in a coreless motor. [Figure 7] This is a schematic diagram showing the total length along the axial direction of the coil's center C and the length of the parallel section. [Figure 8] This graph shows the relationship between the tangent angle θ of the coil and the cross-sectional area of ​​the copper wire in a plane perpendicular to the parallel section. [Figure 9] This graph shows the maximum torque output by one turn of the coil for each coil, where the tangent angle is 38.4° and the ratio of the length of the parallel section to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, and 0.45, and the ratio of the coil pitch to the magnetic pole pitch (for example, 180°) is 0.95, 1.00, 1.05, 1.10, and 1.25 (171, 180, 189, 198, 225°). [Figure 10]This graph shows the maximum torque output by one turn of the coil for each coil, where the tangent angle is 32.0°, and the ratio of the length of the parallel section to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, and 0.45, and the ratio of the coil pitch to the magnetic pole pitch (for example, 180°) is 0.95, 1.00, 1.05, 1.10, and 1.25 (171, 180, 189, 198, 225°). [Figure 11] This graph shows the maximum torque output by one turn of the coil for each coil, where the tangent angle is 25.6°, and the ratio of the length of the parallel section to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, and 0.45, and the ratio of the coil pitch to the magnetic pole pitch (for example, 180°) is 0.95, 1.00, 1.05, 1.10, and 1.25 (171, 180, 189, 198, 225°). [Figure 12] This graph shows the maximum torque output by one turn of the coil for each coil with a tangent angle of 15.0° and a ratio of the length of the parallel section to the total length of the coil set to 0.25, 0.30, 0.35, 0.40, and 0.45, where the ratio of the coil pitch to the magnetic pole pitch (for example, 180°) is 0.95, 1.00, 1.05, 1.10, and 1.25 (171, 180, 189, 198, 225°). [Figure 13] This graph shows the maximum torque output by one turn of a coil when the ratio of the coil pitch to the magnetic pole pitch (for example, 180°) is 0.95 (171°), and the ratio of the length of the parallel section to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, and 0.45, with tangent angles of 38.4, 32.0, 25.6, and 15.0°. [Figure 14]Graph showing the maximum torque output by the conductor of one turn of the coil when the ratio of the coil pitch to the pole pitch (for example, 180[°]) is 1.00 (180[°]), and the ratio of the length of the parallel part to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, 0.45, and the tangent angle is 38.4, 32.0, 25.6, 15.0[°]. [Figure 15] Graph showing the maximum torque output by the conductor of one turn of the coil when the ratio of the coil pitch to the pole pitch (for example, 180[°]) is 1.05 (189[°]), and the ratio of the length of the parallel part to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, 0.45, and the tangent angle is 38.4, 32.0, 25.6, 15.0[°]. [Figure 16] Graph showing the maximum torque output by the conductor of one turn of the coil when the ratio of the coil pitch to the pole pitch (for example, 180[°]) is 1.10 (198[°]), and the ratio of the length of the parallel part to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, 0.45, and the tangent angle is 38.4, 32.0, 25.6, 15.0[°]. [Figure 17] Graph showing the maximum torque output by the conductor of one turn of the coil when the ratio of the coil pitch to the pole pitch (for example, 180[°]) is 1.25 (225[°]), and the ratio of the length of the parallel part to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, 0.45, and the tangent angle is 38.4, 32.0, 25.6, 15.0[°].

Embodiments for Carrying Out the Invention

[0012] Embodiments of the coreless motor according to the present invention will be described as follows with reference to the drawings.

[0013] Figure 1 is a cross-sectional view showing a longitudinal section of the coreless motor 100 including the center C of the rotation axis 20, Figure 2 is a perspective view showing the coil 60 of the coreless motor 100 shown in Figure 1, and Figures 3A, 3B, and 3C are schematic diagrams showing the process of manufacturing the coil 60. The coreless motor 100 is one embodiment of the coreless motor according to the present invention.

[0014] As shown in Figure 1, the coreless motor 100 comprises a rotating shaft 20, a coil 60, a commutator 50, a magnet 30, a brush 40, and a housing 10.

[0015] The housing 10 is formed in a hollow cylindrical shape with both ends closed. The housing 10 houses the rotating shaft 20, the coil 60, the commutator 50, the magnet 30, and the brush 40 inside the hollow interior, with both ends of the rotating shaft 20 protruding outside the housing 10. The housing 10 includes a case 11 and a brush base 12.

[0016] The case 11 is formed in a cylindrical shape with one end closed. The case 11 is made of a soft magnetic material such as metal. The case 11 may be made of multiple components. The brush base 12 is formed in a substantially disc shape so as to close the open end of the case 11. The brush base 12 is made of resin, for example. The brush base 12 is provided with a conductive connecting member (not shown) that is connected to an external power source, and a brush 40 that is electrically connected to this connecting member.

[0017] A rotating shaft 20 is positioned at the center C, which is the cylindrical axis of the housing 10, and passes through the housing 10 so as to be rotatable around the center C. A commutator 50 is fixed to the rotating shaft 20. A coil 60 is fixed to the commutator 50. In other words, the rotor is composed of the rotating shaft 20, the coil 60, and the commutator 50.

[0018] As shown in Figure 2, the coil 60 is formed in a cylindrical shape by winding a conductor 61 (see Figures 3A and 3B). The coil 60 rotates integrally with the rotation shaft 20, about the center C of the rotation shaft 20 as its axis. The coil 60 is formed by assembling multiple coil elements, each wound with a conductor 61. The coil 60 is constructed so that its cylindrical outer surface 60A does not come into contact with the inner surface 11B of the case 11. Details of the coil 60 will be described later.

[0019] The commutator 50 is formed in a disc shape with a boss in its center through which the rotating shaft 20 passes. The outer circumference of the disc of the commutator 50 is bonded with adhesive to the inner circumference of one end of the cylindrical coil 60 that is closer to the brush base 12, thereby integrating it with the coil 60. The commutator 50 is integrally connected to the rotating shaft 20 that passes through the boss, and as a result, the commutator 50 rotates together with the rotating shaft 20 around the center C.

[0020] The commutator 50 has conductive members that are electrically connected to the terminals 61a, 61b (see Figures 2, 3A, 3B) of each conductor 61 of the multiple coil elements that make up the coil 60, and these conductive members extend to the outer surface of the boss and come into contact with the brush 40 provided on the brush base 12.

[0021] The magnet 30 is positioned inside the cylinder of the coil 60 so as not to be in contact with the inner circumferential surface 60B of the coil 60. The magnet 30 is formed in a cylindrical shape with its center C as its axis. The magnet 30 is formed so that its outer circumferential surface 30A is not in contact with the inner circumferential surface 60B of the coil 60. The inner circumferential surface 30B of the magnet 30 is fixed to the outer circumferential surface of a cylindrical support member 28 which is fixed to the case 11.

[0022] As a result, the magnet 30 is indirectly fixed to the case 11 and does not displace relative to the case 11. Inside the support member 28, bearings 25 are arranged at both ends in the longitudinal direction of the support member 28, and the rotating shaft 20 is rotatably supported by these two bearings 25.

[0023] Next, the details of the coil 60 will be described. The coil 60 is basically made up of conductors 61 joined together with adhesive, and does not have a core such as an iron core. For this reason, the coil 60 is lighter than a coil that has a core.

[0024] As shown in Figure 3A, the coil 60 is formed by winding a conductor 61 (for example, copper wire) around the outer surface of a winding jig 500, which has a hexagonal cross-section, for example, in the shape of a hexagonal prism. At this time, by slightly shifting the position where the conductor 61 is wound around each turn (one turn around the outer surface of the hexagonal prism) in the axial direction of the hexagonal prism, one turn of the coil 60 projects in the axial direction to form a hexagonal shape (tortoise shell shape), and the coil 60 as a whole is a hexagonal spiral.

[0025] In Figures 3A and 3B, the hexagonal shapes formed by the conductors 61 are depicted as separate and independent. This is for the sake of simplicity in the diagrams; in reality, the conductors 61 represented by these multiple hexagonal shapes are connected at both ends of one turn of conductor 61 in each hexagonal shape to the ends of one turn of conductor 61 in the adjacent hexagonal shape, forming a single spiral. This spirally formed conductor 61 has two ends 61a and 61b.

[0026] By pulling the winding jig 500 axially out of the hexagonal spiral coil 60 formed in this way, a coil 60 formed in a hexagonal spiral shape using only the conductor wire 61 is obtained. Then, the edges of the coil 60 corresponding to the opposing faces of the hexagonal prism of the winding jig 500 are moved in opposite directions along the axial direction of the hexagonal prism (indicated by "→" in Figure 3A) to form a flattened coil 60 in the planar shape shown in Figure 3B.

[0027] The wire 61 for one turn of the coil 60 has a tortoise-shell shape (hexagonal shape) corresponding to the cross-sectional shape of the winding jig 500. As shown in Figure 3B, this tortoise-shell shape has a parallel section 62 that extends parallel to the axis (center C) of the rotation axis 20, and two slanted sections 63 and 64 connected to both ends of the parallel section 62. The wires 61 of the slanted sections 63 and 64 extend linearly in a direction inclined by a predetermined angle with respect to a plane perpendicular to the direction of center C. The inclination angles of the slanted section 63 and the slanted section 64 are in different directions but have the same absolute value.

[0028] The coil 60 shown in Figure 3B is then deformed so that the linear hypotenuses 63 and 64, shown by the dashed lines in Figure 3C, become convex from the inside to the outside of one turn (hexagonal shape) of the coil 60, forming a curved shape that is convex outwards, as shown by the solid line in Figure 3C. In the coil 60 of this embodiment, this curve is, for example, a circular arc, but in the coreless motor according to the present invention, the curve of the coil is not limited to a circular arc. For example, the curve of the coil may be an elliptical arc, a parabola, or a plurality of interconnected straight lines that approximate these curves (circular arc, elliptical arc, parabola).

[0029] A coil 60 with the shape shown in Figure 3C is used as one coil element. Multiple such coil elements are connected in the axial direction of the aforementioned hexagonal prism, and one surface 60A of the planarly formed coil element is the outward-facing surface (outer surface), and the other surface 60B is the inward-facing surface (inner surface). By connecting the axial ends around the center C shown in Figure 3B, a cylindrical coil 60 is formed as shown in Figure 2. Note that the method of forming the curve of the coil 60 is not limited to the method described above.

[0030] For example, instead of the hexagonal prism-shaped winding jig 500, the curve of the coil 60 may be formed by winding the conductor 61 around a columnar winding jig in which two circumferential surfaces corresponding to the parallel sections 62 of the hexagonal prism are formed as flat surfaces, and the other four circumferential surfaces, excluding these two, are formed as outwardly convex curved surfaces rather than flat surfaces. This formation method allows for the accurate and easy formation of the curve of the coil 60.

[0031] The coil 60 formed in this manner is a tortoise-shell shaped (hexagonal) coil 60, and as shown in Figure 2, both the outer surface 60A and the inner surface 60B of this coil 60 have a parallel portion 62 extending parallel to the axis (center C) of the rotation axis 20, a slanted portion 63 connected to one end of the parallel portion 62, and a slanted portion 64 connected to the other end of the parallel portion 62.

[0032] As shown in Figure 5, the conductors 61 of each hypotenuse 63 and 64 are in contact with a plane perpendicular to the direction in which the parallel portion 62 extends at a predetermined angle θ at their ends along the length of the parallel portion 62 of the coil 60 (in the axial direction of the center C).

[0033] In other words, at the longitudinal end of the coil 60, the angle between the tangent to the curve drawn from the vertex of the hexagon where two adjacent hypotenuse sections 63, 63 (hypotenuse sections 63a, 63b) connect to each other (the tangent to hypotenuse sections 63a, 63b) and the plane perpendicular to the axis of the center C, and the angle between the tangent to the curve drawn from the vertex of the hexagon where two adjacent hypotenuse sections 64, 64 (hypotenuse sections 64a, 64b) connect to each other (the tangent to hypotenuse sections 64a, 64b) and the plane perpendicular to the axis of the center C, are both angles θ.

[0034] In the following explanation, this angle θ will be referred to as the tangent angle θ of the hypotenuse 63,64. Note that in Figure 5, the tangent angle θ is drawn only to the left of the center C on the plane of the paper, but it also exists to the right of the center C, symmetrically with respect to the axis of center C.

[0035] When it is necessary to distinguish between the parallel portion 62 on the outer circumferential surface 60A and the parallel portion 62 on the inner circumferential surface 60B of the coil 60, as shown in Figure 3B, the parallel portion 62 on the outer circumferential surface 60A is designated as parallel portion 62a, and the parallel portion 62 on the inner circumferential surface 60B is designated as parallel portion 62b. Similarly, when it is necessary to distinguish between the slanted portions 63,64 on the outer circumferential surface 60A and the slanted portions 63,64 on the inner circumferential surface 60B of the coil 60, the slanted portions 63,64 on the outer circumferential surface 60A are designated as slanted portions 63a,64a, and the slanted portions 63,64 on the inner circumferential surface 60B are designated as slanted portions 63b,64b.

[0036] Figure 4 schematically shows the positional relationship between the magnet 30 and the hexagonal shape of one turn of the coil 60. In the coreless motor 100 of this embodiment, the magnet 30 is formed with one north pole 30N and one south pole 30S on either side of the axis of the center C, as shown in Figure 4. In other words, the magnet 30 is formed with the north pole 30N and the south pole 30S arranged at an angular interval (angular pitch) of 180 degrees around the axis of the center C of the magnet 30.

[0037] Figure 6 is a schematic diagram showing the relationship between the magnetic pole pitch α and the coil pitch β in the coreless motor 100, and also shows the magnetic force distribution expressed by trigonometric functions, where the magnetic force of the magnet 30 is maximum at the center of the N pole 30N and the center of the S pole 30S, respectively. Figure 7 is a schematic diagram showing the total length L0 along the axial direction of the center C of the coil 60 and the length L1 of the parallel section 62.

[0038] As shown in Figure 6, the centers of the north pole 30N (N pole center) and south pole 30S (S pole center) of magnet 30 are the angular positions where the absolute value of the magnetic force distribution of magnet 30 is maximized. In the following explanation, the angular pitch (angle interval) between the center of the north pole 30N and the center of the south pole 30S of magnet 30 along the circumferential direction D around the axis C is referred to as the magnetic pole pitch α.

[0039] In the coreless motor 100 of this embodiment, the coil 60 is formed such that the two parallel sections 62, 62 of the hexagonal shape of one turn (see Figure 5) are arranged at an angular interval (angular pitch) around the axis C of the magnet 30, as shown in Figure 6. In the following description, the angular pitch (angular interval) between the two parallel sections 62, 62 of the coil 60 along the circumferential direction D around the axis C is referred to as the coil pitch β.

[0040] In this embodiment, the coreless motor 100 has a coil 60 whose ratio of coil pitch β to magnetic pole pitch α (ratio of angular pitch) β / α is set to a range of 1.00 (100%) or more and 1.25 (125%) or less. For example, when the magnetic pole pitch α of the magnet 30 in the coreless motor 100 is 180 degrees, an angular pitch ratio of 1.00 (100%) corresponds to a coil pitch β of 180 degrees, and an angular pitch ratio of 1.25 (125%) corresponds to a coil pitch β of 225 degrees.

[0041] Furthermore, in the coreless motor 100, the ratio L1 / L0 of the length of the parallel portion 62 to the total length L0 along the axial direction of the center C, as shown in Figure 7, is set to be, for example, 0.25 (25%) or more and 0.75 (75%) or less.

[0042] Here, the maximum torque T output by the coreless motor 100 due to the magnetic force acting on the conductor 61 of the coil 60 in the magnetic field of the magnet 30 is given by the following equation (1).

[0043] T=2*B*I*r*L*sinθi (1) However, in equation (1), B is the magnetic flux due to the magnet 30, I is the current flowing through the coil 60, r is the radius of the coil 60 (dimension along the radial direction R), L is the length of the coil 60 (dimension along the direction of the center C), and θi is the angle of inclination of the conductor 61 in the coil 60 with respect to a plane perpendicular to the direction of the center C (90 degrees in the parallel section 62, and changing from θ in the upper hypotenuse section 63 and the lower hypotenuse section 64).

[0044] In other words, the maximum torque T output by the coreless motor 100 is greater the larger the area of ​​the region indicated by the shaded area in Figure 5. Therefore, in the coreless motor 100 of this embodiment, the area of ​​the shaded region shown in Figure 5 is increased compared to a coil with the straight hypotenuse portions 63 and 64 shown by the dashed line in Figure 3C. As a result, the magnetic flux acting on the coil 60 as a whole increases, and the maximum torque T output, which is a characteristic of the coreless motor 100, can be increased.

[0045] Furthermore, by decreasing the tangent angle θ of the coil 60 shown in Figure 5, the area of ​​the shaded region can be increased, thereby increasing the maximum torque T output by the coreless motor 100. However, in this case, the cross-sectional area of ​​the conductor 61 (copper wire) at the ends of the coil 60 in the longitudinal direction of the hypotenuse 63 and 64, due to the plane perpendicular to the parallel section 62, increases as the tangent angle θ decreases, as shown in Table 1 and Figure 8. Here, the specific values ​​of the cross-sectional area of ​​the conductor 61 shown in Table 1 and Figure 8 are examples where the diameter of the conductor 61 is 0.1 [mm]. Therefore, in this example, the cross-sectional area of ​​the conductor 61 at the parallel section 62, due to the plane perpendicular to the parallel section 62, is 0.0078 [mm]. 2 ] Figure 8 is a graph of Table 1.

[0046] [Table 1]

[0047] Furthermore, as the cross-sectional area of ​​the conductors 61 in the hypotenuse sections 63 and 64 increases, it becomes more difficult for the conductors 61 to align with each other, resulting in a lower packing ratio of the conductors 61 in the parallel section 62, and an increase in the thickness of the ends of the coil 60 in the longitudinal direction. Therefore, as can be seen from the graph in Figure 8, the coreless motor 100 is preferably in a range where the cross-sectional area of ​​the conductors 61 does not increase rapidly with respect to a decrease in the tangent angle θ, that is, in a range where the packing ratio in the parallel section 62 does not fall below approximately 30%, that is, in a range where the cross-sectional area of ​​the conductors 61 in the hypotenuse sections 63 and 64 does not exceed three times the cross-sectional area of ​​the conductors 61 in the parallel section 62, and in particular, it is preferable that the tangent angle θ is in a range of 20 degrees or more, where the packing ratio of the conductors 61 in the parallel section 62 and the thickness of the ends of the coil 60 in the longitudinal direction are within a more practical range.

[0048] Furthermore, the maximum torque T output by the coreless motor 100 decreases to an impractical value when the tangent angle θ of the hypotenuses 63 and 64 exceeds 50 degrees. Therefore, from the viewpoint of keeping the maximum torque T output by the coreless motor 100 within a practical range, it is preferable that the tangent angle θ is 50 degrees or less, and furthermore,

[0049] In other words, the tangent angle θ is preferably 15 degrees or more and 50 degrees or less, particularly preferably 20 degrees or more and 50 degrees or less, and even more preferably 20 degrees or more and 35 degrees or less.

[0050] In the coreless motor 100 of this embodiment, when the tangent angle θ of the coil 60 is set to 38.4 degrees, 32.0 degrees, 25.6 degrees, and 15.0 degrees, the ratio of the coil pitch β to the magnetic pole pitch α (angle-pitch ratio) β / α is changed from 0.95 (95%) to 1.25 (125%), and the ratio of the length L1 of the parallel portion 62 to the total length L0 of the coil 60 (length ratio) L1 / L0 is changed from 0.25 (25%) to 0.45 (45%), the maximum torque output by one turn of the conductor 61 of the coil 60 of the coreless motor 100 is shown in Tables 2 to 5 and Figures 9 to 12. Figures 9 to 12 are graphs of Tables 2 to 5, respectively.

[0051] [Table 2]

[0052] [Table 3]

[0053] [Table 4]

[0054] [Table 5]

[0055] Furthermore, in the coreless motor 100 of this embodiment, when the ratio of coil pitch β to magnetic pole pitch α (ratio of angular pitch) β / α is set to 0.95 (95%), 1.00 (100%), 1.05 (105%), 1.10 (110%), and 1.20 (120%), and the tangent angle θ is changed from 38.4 degrees to 15.0 degrees, and the ratio of the length L1 of the parallel portion 62 to the total length L0 of the coil 60 (ratio of lengths) L1 / L0 is changed from 0.25 (25%) to 0.45 (45%), the maximum torque output by the conductor 61 of one turn of the coil 60 of the coreless motor 100 is shown in Tables 6 to 10 and Figures 13 to 17. Figures 13-17 are graphs of Tables 6-10, respectively.

[0056] [Table 6]

[0057] [Table 7]

[0058] [Table 8]

[0059] [Table 9]

[0060] [Table 10]

[0061] As shown in the graphs in Figures 9 to 17, the coreless motor 100 of this embodiment can increase the maximum torque T output by the coreless motor 100 as the tangent angle θ decreases. Furthermore, in the range where the angular pitch ratio β / α is greater than 1.00 (100%) to 1.10 (110%) or less, the maximum torque T output by the coreless motor 100 can be increased compared to the case where the angular pitch ratio β / α is 1.00 (100%). In addition, the larger the length ratio L1 / L0, the greater the maximum torque T output by the coreless motor 100.

[0062] According to the graphs shown in Figures 13 to 17 above, in order to increase the maximum torque T of the coreless motor 100 of this embodiment, it is preferable that the tangent angle θ is in the range of 15 degrees or more and 50 degrees or less. In particular, considering the graph shown in Figure 8 above, it is preferable that the tangent angle θ is in the range of 20 degrees or more and 35 degrees or less in order to minimize the increase in the cross-sectional area of ​​the conductor 61 in the hypotenuse portions 63 and 64.

[0063] Furthermore, as shown in the graphs in Figures 9 to 12 above, in order to increase the maximum torque T of the coreless motor 100 of this embodiment, in addition to the range of tangential angles θ above, it is preferable that the angular pitch ratio β / α is in the range of over 1.00 (100[%]) to 1.10 (110[%]) or less, and in particular, it is preferable that the angular pitch ratio β / α is in the range of 1.05 (105[%]) or more and 1.10 (110[%]) or less, which is the range in which the maximum torque T is maximized.

[0064] Furthermore, in addition to the range of the tangential angle θ and the angle pitch ratio β / α described above, the coreless motor 100 of this embodiment preferably has a length ratio L1 / L0 in the range of 0.25 (25%) or more and 0.75 (75%) or less, and in particular, it is preferable that the length ratio L1 / L0 is in the range of 0.25 (25%) or more and 0.45 (45%) or less.

[0065] Furthermore, in the case of the coreless motor 100 of this embodiment, as described above, the tangent angle θ is in the range of 15 degrees or more and 50 degrees or less, and in addition, when the length ratio L1 / L0 is 0.25 (25%) or more and 0.75 (75%) or less, it is preferable that the angular pitch ratio β / α is in the range of more than 1.00 (100%) and 1.10 (110%) or less.

[0066] However, the coreless motor 100 can, for example, as shown in Figure 9 above, when the tangent angle θ is 38.4 degrees and the length ratio L1 / L0 is 0.25 (25%), obtain an output that exceeds the maximum torque T when the angular pitch ratio β / α is 1.00 (100%), even when the angular pitch ratio β / α is increased from over 1.00 (100%) to 1.25 (125%), that is, when the upper limit of the angular pitch ratio β / α is increased from 1.10 (110%) to 1.25 (125%).

[0067] Furthermore, as shown in Figures 9-11 above, the coreless motor 100 can, for example, when the tangent angle θ is 38.4 degrees, 32.0 degrees, and 25.6 degrees, even when the angular-pitch ratio β / α is in the range from over 1.00 (100%) to 1.15 (115%), that is, when the upper limit of the angular-pitch ratio β / α is raised from 1.10 (110%) to 1.15 (115%), it can still produce an output exceeding the maximum torque T when the angular-pitch ratio β / α is 1.00 (100%).

[0068] Therefore, when the tangent angle θ of the coreless motor 100 is 38.4 degrees and the length ratio L1 / L0 is 0.25 (25%), the angular pitch ratio β / α can be in the range of over 1.00 (100%) to 1.25 (125%).

[0069] Furthermore, for the coreless motor 100, when the tangent angle θ is 38.4 degrees, 32.0 degrees, or 25.6 degrees, the angular pitch ratio β / α can be set to a range from over 1.00 (100%) to 1.15 (115%).

[0070] In this embodiment, the coreless motor 100 can achieve a larger maximum output torque T as the length ratio L1 / L0 increases. However, as the length ratio L1 / L0 increases, the cross-sectional area of ​​the conductor 61 in the hypotenuse portions 63 and 64 increases, and the space factor of the conductor 61 in the parallel portion 62 decreases.

[0071] Furthermore, if the space factor of the conductors 61 in the parallel section 62 becomes smaller than a predetermined value, the strength of the parallel section 62 decreases, and the centrifugal force acting when it rotates around the center C may deform the coil 60, potentially causing it to come into contact with the housing 10. For this reason, the coil 60 must have sufficient strength to not deform at the rated rotation speed of the coreless motor 100.

[0072] As a result, the coreless motor 100 of this embodiment sets the upper limit of the length ratio L1 / L0 to 0.75 (75%), taking into account the strength that the coil 60 should possess. In particular, to ensure that the strength of the coil 60 is sufficiently large, taking into account the safety factor at the rated rotation, it is preferable that the upper limit of the length ratio L1 / L0 of the coreless motor 100 be 0.45 (45%).

[0073] Furthermore, in this embodiment, the coreless motor 100 has a lower limit of the coil length ratio L1 / L0 of 60 at 0.25 (25%), because this makes it easier for the coreless motor 100 to output the minimum maximum torque T that is normally required. If the length ratio L1 / L0 of the coreless motor 100 becomes smaller than 0.25 (25%), it becomes difficult for the coreless motor 100 to output a sufficient maximum torque T.

[0074] Based on the above, the coreless motor 100 of this embodiment has a tangential angle θ set in the range of 15 degrees to 50 degrees, an angular pitch ratio β / α set in the range of more than 1.00 and 1.25 or less, and a length ratio L1 / L0 set in the range of 0.25 to 0.75.

[0075] In this embodiment, it is most preferable that the coreless motor 100 has a tangential angle θ set in the range of 20 degrees to 35 degrees, an angular pitch ratio β / α set in the range of 1.05 to 1.10, and a length ratio L1 / L0 set in the range of 0.25 to 0.45.

[0076] In this embodiment, the coreless motor 100, with its tangent angle θ, angle-pitch ratio β / α, and length ratio L1 / L0 set as described above, becomes a practical coreless motor with a large maximum output torque T.

[0077] Furthermore, according to the results of verification by the applicant of this application, the coreless motor 100 of this embodiment was able to increase the maximum output torque T by, for example, up to approximately 10% compared to a conventional coreless motor equipped with a hexagonal (tortoiseshell-shaped) coil in which the hypotenuses 63 and 64 are formed in a straight line.

[0078] The coreless motor 100 in the above-described embodiment is an outer rotor type coreless motor in which the coil 60 is arranged outside the magnet 30. However, the coreless motor according to the present invention is not limited to an outer rotor type coreless motor, and may be an inner rotor type coreless motor in which the coil 60 is arranged inside the magnet 30. In the case of an inner rotor type coreless motor, the outer circumferential surface of the magnet 30 is fixed to, for example, the inner circumferential surface of the case 11.

[0079] In the embodiment described above, the magnet 30 of the coreless motor 100 has one N pole 30N and one S pole 30S formed thereon. However, the magnet of the coreless motor according to the present invention may have two N poles 30N and two S poles 30S formed thereon, or it may have more magnetic poles than that.

Claims

1. (delete)

2. The axis of rotation and A coil formed by winding a wire into a cylindrical shape and rotating integrally with the aforementioned rotating shaft, The coil comprises a cylindrical magnet positioned inside or outside the cylindrical shape of the coil, Each turn of the coil is formed in a hexagonal shape, having a parallel portion extending parallel to the axial direction of the rotation axis, and two slanted portions connected to both ends of the parallel portion, which are inclined with respect to a plane perpendicular to the axial direction. The aforementioned slanted portion is formed in a curved shape that is convex from the inside to the outside of one turn of the coil, A coreless motor in which the tangent angle, which is the angle between the tangent to the hypotenuse drawn from the vertex connecting the ends of two adjacent hypotenuses in one turn of the coil and the plane perpendicular to the axial direction, is set to a range of 20 degrees or more and 35 degrees or less.

3. The axis of rotation and A coil formed by winding a wire into a cylindrical shape and rotating integrally with the aforementioned rotating shaft, The coil comprises a cylindrical magnet positioned inside or outside the cylindrical shape of the coil, Each turn of the coil is formed in a hexagonal shape, having a parallel portion extending parallel to the axial direction of the rotation axis, and two slanted portions connected to both ends of the parallel portion, which are inclined with respect to a plane perpendicular to the axial direction. The aforementioned slanted portion is formed in a curved shape that is convex from the inside to the outside of one turn of the coil, The tangent angle, which is the angle between the tangent to the hypotenuse drawn from the vertex connecting two adjacent hypotenuses in one turn of the coil and the plane perpendicular to the axial direction, is set to a range of 15 degrees or more and 50 degrees or less. A coreless motor in which the ratio β / α of the angular spacing β between the two parallel portions in one turn of the coil to the angular spacing α between the magnetic poles of the magnet is set to a range of greater than 1.00 and less than or equal to 1.

25.

4. The coreless motor according to claim 3, wherein the ratio β / α of the angular spacing β between the two parallel portions in one turn of the coil to the angular spacing α between the magnetic poles of the magnet is set to a range of 1.05 or more and 1.10 or less.

5. The coreless motor according to claim 2, wherein the ratio L1 / L0 of the length of the parallel portion of one turn of the coil to the total length L0 along the axial direction is set to a range of 0.25 or more and 0.75 or less.

6. The coreless motor according to claim 2, wherein the ratio L1 / L0 of the length of the parallel portion of one turn of the coil to the total length L0 along the axial direction is set to a range of 0.25 or more and 0.45 or less.

7. The axis of rotation and A coil formed by winding a wire into a cylindrical shape and rotating integrally with the aforementioned rotating shaft, The coil comprises a cylindrical magnet positioned inside or outside the cylindrical shape of the coil, Each turn of the coil is formed in a hexagonal shape, having a parallel portion extending parallel to the axial direction of the rotation axis, and two slanted portions connected to both ends of the parallel portion, which are inclined with respect to a plane perpendicular to the axial direction. The aforementioned slanted portion is formed in a curved shape that is convex from the inside to the outside of one turn of the coil, The tangent angle, which is the angle between the tangent to the hypotenuse drawn from the vertex connecting two adjacent hypotenuses in one turn of the coil and the plane perpendicular to the axial direction, is set to a range of 15 degrees or more and 50 degrees or less. The ratio β / α of the angular spacing β between the two parallel portions in one turn of the coil to the angular spacing α between the magnetic poles of the magnet is set to a range greater than 1.00 and less than or equal to 1.

25. A coreless motor in which the ratio L1 / L0 of the length of the parallel portion of one turn of the coil to the total length L0 along the axial direction is set to a range of 0.25 or more and 0.75 or less.

8. The axis of rotation and A coil formed by winding a wire into a cylindrical shape and rotating integrally with the aforementioned rotating shaft, The coil comprises a cylindrical magnet positioned inside or outside the cylindrical shape of the coil, Each turn of the coil is formed in a hexagonal shape, having a parallel portion extending parallel to the axial direction of the rotation axis, and two slanted portions connected to both ends of the parallel portion, which are inclined with respect to a plane perpendicular to the axial direction. The aforementioned slanted portion is formed in a curved shape that is convex from the inside to the outside of one turn of the coil, The tangent angle, which is the angle between the tangent to the hypotenuse drawn from the vertex connecting two adjacent hypotenuses in one turn of the coil and the plane perpendicular to the axial direction, is set to a range of 20 degrees or more and 35 degrees or less. The ratio β / α of the angular spacing β between the two parallel portions in one turn of the coil to the angular spacing α between the magnetic poles of the magnet is set to a range of 1.05 or more and 1.10 or less. A coreless motor in which the ratio L1 / L0 of the length of the parallel portion of one turn of the coil to the total length L0 along the axial direction is set to a range of 0.25 or more and 0.45 or less.

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