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

Coreless motor

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

[0002] Coreless motors do not have an iron core where the coil serves as the core, and the rotor is formed only by windings. One way to wind the conductor to form the coil is to form it in a hexagonal (tortoiseshell) shape. In this tortoiseshell winding method, for example, the conductor is wound circumferentially around the outer surface of a hexagonal prism while being shifted slightly in the axial direction of the hexagonal prism to form a hexagonal spiral coil element, and the hexagonal prism is then pulled out axially from the coil element to obtain a coil element formed in the spiral shape of a hexagonal prism using only the conductor.

[0003] Then, the sides corresponding to the opposing faces of the hexagonal prism are moved in opposite directions along the axial direction of the hexagonal prism to flatten it into a planar shape, and multiple of the resulting planar coil elements are strung together and connected at their axial ends to form a cylindrical coil.

[0004] The cylindrical coil has, on both the outer and inner surfaces, a parallel section where the conductor is parallel to the axis of the cylinder, and two oblique sections where the conductor is connected to the parallel section and is inclined with respect to a plane perpendicular to the axis of the cylinder. Here, it has also been proposed to form the oblique sections into arc-shaped curves to increase the magnetic flux passing through the oblique sections (see, for example, Patent Document 1).

[0005] In addition, it has also been proposed to wind the conductor in a rectangular shape rather than a hexagonal (tortoiseshell) shape, and to form the oblique side of a coil with no parallel parts in an arc shape (see, for example, Patent Document 2).

[0006] JP 2014-054026 A JP 55-023788 A

[0007] The coils shown in the above-mentioned prior art documents increase the magnetic flux passing through by forming the hypotenuse portion in a curved shape, but do not specifically define a practical shape for the curve of the hypotenuse portion.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a coreless motor in which the practical shape of the curved hypotenuse of the hexagonal (tortoiseshell) coil is specifically defined in order to improve the motor's characteristics.

[0009] The present invention is a coreless motor comprising: a rotating shaft; a coil formed into a cylindrical shape by winding a conductor and rotating integrally with the rotating shaft; and a cylindrical magnet arranged inside or outside the cylindrical shape of the coil, wherein each turn of the coil is formed into a hexagonal shape having a parallel portion where the conductor extends parallel to the axial direction of the rotating shaft and two oblique portions connected to both ends of the parallel portion and inclined with respect to a plane perpendicular to the axial direction, the oblique portions are formed in a curve that is convex from the inside to the outside of the single turn of the coil, and the tangent angle, which is the angle between the tangent to the oblique portion drawn from the vertex connecting one end of two adjacent oblique portions in the single 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.

[0010] The coreless motor according to the present invention exhibits excellent motor characteristics because the curved lines of the hypotenuses of the hexagonal (hexagonal) coils have a practically defined shape.

[0011] 1 is a cross-sectional view showing a longitudinal section of a coreless motor of embodiment 1, including the center C of the rotating shaft. FIG. 2 is a side view showing a coil of the coreless motor shown in FIG. 1. FIG. 3 is a schematic view showing a first step in manufacturing the coil shown in FIG. 2. FIG. 4 is a schematic view showing a second step in manufacturing the coil shown in FIG. 2. FIG. 5 is a schematic view showing a third step in manufacturing the coil shown in FIG. 2. FIG. 6 is a schematic view showing the positional relationship between a magnet and a hexagonal shape for one turn of the coil. FIG. 7 is a schematic view showing a tangent angle θ, which is the angle between a tangent to the hypotenuse of the coil and a plane perpendicular to the parallel portion. FIG. 8 is a schematic view showing the magnitude relationship between the magnetic pole pitch and the coil pitch in a coreless motor. FIG. 9 is a schematic view showing the overall length along the axial direction of the center C of the coil and the length of the parallel portion. FIG. 10 is a graph showing 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 portion. 10 is a graph showing the maximum torque output by one turn of wire in a coil when the ratio of the coil pitch to the magnetic pole pitch (180°, for example) is 0.95, 1.00, 1.05, 1.10, 1.25 (171, 180, 189, 198, 225°) for each coil with a tangent angle of 38.4° and a ratio of the length of the parallel portion to the total length of the coil of 0.25, 0.30, 0.35, 0.40, 0.45. 10 is a graph showing the maximum torque output by one turn of wire in a coil when the ratio of the coil pitch to the magnetic pole pitch (180°, for example) is 0.95, 1.00, 1.05, 1.10, 1.25 (171, 180, 189, 198, 225°) for each coil with a tangent angle of 32.0° and a ratio of the length of the parallel portion to the total length of the coil of 0.25, 0.30, 0.35, 0.40, 0.45. 10 is a graph showing the maximum torque output by one turn of wire in a coil when the ratio of the coil pitch to the magnetic pole pitch (180°, for example) is 0.95, 1.00, 1.05, 1.10, 1.25 (171, 180, 189, 198, 225°) for each coil with a tangent angle of 25.6° and a ratio of the length of the parallel portion to the total length of the coil of 0.25, 0.30, 0.35, 0.40, 0.45.10 is a graph showing the maximum torque output by one turn of wire in a coil when the ratio of the coil pitch to the magnetic pole pitch (180°, for example) is 0.95, 1.00, 1.05, 1.10, 1.25 (171, 180, 189, 198, 225°) for each coil with a tangent angle of 15.0° and a ratio of the length of the parallel portion to the total length of the coil of 0.25, 0.30, 0.35, 0.40, 0.45. 10 shows the maximum torque output by one turn of wire in a coil having a ratio of 0.95 (171°) to the magnetic pole pitch (180°, for example), a ratio of the length of the parallel portion to the total length of the coil set to 0.25, 0.30, 0.35, 0.40, and 0.45, and a tangent angle of 38.4, 32.0, 25.6, and 15.0°. 11 shows the maximum torque output by one turn of wire in a coil having a ratio of 1.00 (180°) to the magnetic pole pitch (180°, for example), a ratio of 0.25, 0.30, 0.35, 0.40, and 0.45, and a tangent angle of 38.4, 32.0, 25.6, and 15.0°. 10 shows the maximum torque output by one turn of wire in a coil having a ratio of 1.05 (189°) to the magnetic pole pitch (180°, for example), a ratio of the length of the parallel portion to the total length of the coil set to 0.25, 0.30, 0.35, 0.40, and 0.45, and a tangent angle of 38.4, 32.0, 25.6, and 15.0°. 11 shows the maximum torque output by one turn of wire in a coil having a ratio of 1.10 (198°) to the magnetic pole pitch (180°, for example), a ratio of the length of the parallel portion to the total length of the coil set to 0.25, 0.30, 0.35, 0.40, and 0.45, and a tangent angle of 38.4, 32.0, 25.6, and 15.0°.This graph shows the maximum torque output by one turn of wire in each coil when the tangent angle is 38.4, 32.0, 25.6, and 15.0° for coils where the ratio of the coil pitch to the magnetic pole pitch (180°, for example) is 1.25 (225°), and the ratio of the length of the parallel portion to the total length of the coil is set to 0.25, 0.30, 0.35, 0.40, and 0.45.

[0012] An embodiment of a coreless motor according to the present invention will be described below with reference to the drawings.

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

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

[0015] The housing 10 is formed in a hollow cylindrical shape with both ends closed. The housing 10 accommodates a rotating shaft 20, a coil 60, a commutator 50, a magnet 30, and brushes 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 formed of a soft magnetic material such as metal. The case 11 may be formed of multiple members. The brush base 12 is formed in a generally circular plate shape so as to close the open end of the case 11. The brush base 12 is formed of, for example, resin. The brush base 12 is provided with a conductor connecting member (not shown) that is connected to an external power source, and brushes 40 that are electrically connected to this connecting member.

[0017] A rotating shaft 20 is disposed at the center C, which is the axis of the cylinder of the housing 10, and passes through the housing 10 so as to be rotatable about 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 rotating shaft 20, the coil 60, and the commutator 50 constitute a rotor.

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

[0019] The commutator 50 is formed in the shape of a disk having a boss at the center through which the rotary shaft 20 passes. The outer periphery of the disk of the commutator 50 is bonded with an adhesive to the inner periphery of one end of the cylindrical coil 60, which is closer to the brush base 12, thereby being integrated with the coil 60. The commutator 50 is integrally connected to the rotary shaft 20 which passes through the boss, and as a result, the commutator 50 rotates around the center C together with the rotary shaft 20.

[0020] The commutator 50 has a conductive member electrically connected to the terminals 61a, 61b (see Figures 2, 3A, and 3B) of each of the conductors 61 of the multiple coil elements that make up the coil 60, and this conductive member extends to the outer surface of the boss and contacts the brush 40 provided on the brush base 12.

[0021] Magnet 30 is disposed inside the cylinder of coil 60 so as not to come into contact with inner peripheral surface 60B of coil 60. Magnet 30 is formed in a cylindrical shape with its axis at center C. Magnet 30 is formed so that outer peripheral surface 30A does not come into contact with inner peripheral surface 60B of coil 60. Magnet 30 has inner peripheral surface 30B fixed to the outer peripheral surface of cylindrical support member 28 fixed to 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, details of the coil 60 will be described. The coil 60 is basically made up of conductive wires 61 joined together with an adhesive, and does not have a core such as an iron core. Therefore, the coil 60 is lighter than a coil with a core.

[0024] As shown in FIG. 3A , the coil 60 is formed by winding a conductor 61 (e.g., a copper wire) around the outer surface of a winding jig 500 having a hexagonal cross section, e.g., a hexagonal prism shape. At this time, the position at which the conductor 61 is wound is shifted slightly in the axial direction of the hexagonal prism for each turn of the winding (each turn around the outer surface of the hexagonal prism), so that one turn of the coil 60 has a hexagonal shape (tortoiseshell shape) when projected in the axial direction, forming the coil 60 in an overall hexagonal spiral shape.

[0025] In Figures 3A and 3B, the hexagonal shapes formed by the conductor 61 are depicted as if they were separate and independent, but this is for the convenience of simplifying the depiction in the figures. In reality, the conductor 61 depicted as multiple hexagonal shapes has both ends of one turn of the conductor 61 in each hexagonal shape connected to the ends of one turn of the conductor 61 in the adjacent hexagonal shape to form a single spiral, and this single spiral-shaped conductor 61 has two terminals 61a and 61b.

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

[0027] One turn of the conductor 61 of the coil 60 has a tortoiseshell (hexagonal) shape that corresponds to the cross-sectional shape of the winding jig 500. As shown in Fig. 3B, this tortoiseshell shape is such that the conductor 61 has a parallel portion 62 extending parallel to the axial direction (center C) of the rotating shaft 20, and two oblique portions 63, 64 connected to both ends of the parallel portion 62. The oblique portions 63, 64 of the conductor 61 extend linearly in a direction inclined by a predetermined angle with respect to a plane perpendicular to the direction of the center C. The inclination angle of the oblique portion 63 and the inclination angle of the oblique portion 64 differ in direction but have the same absolute value.

[0028] The coil 60 shown in Figure 3B is then deformed such that the linear hypotenuses 63 and 64 indicated by the two-dot chain lines in Figure 3C are convex from the inside to the outside of one turn (hexagonal shape) of the coil 60, forming the curved shape indicated by the solid line in Figure 3C that is convex outward. 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 connected straight lines that approximate these curves (circular arc, elliptical arc, parabola).

[0029] A coil 60 having the shape shown in Fig. 3C is used as one coil element, and a plurality of such coil elements are connected in the axial direction of the above-mentioned hexagonal prism, and the ends in the axial direction are connected around the center C shown in Fig. 3B so that one surface 60A of the planar coil element faces outward (outer circumferential surface) and the other surface 60B faces inward (inner circumferential surface), thereby forming the cylindrical coil 60 shown in Fig. 2. Note that the method for 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, a cylindrical winding jig may be used in which two peripheral surfaces of a hexagonal prism corresponding to the parallel portion 62 are formed as flat surfaces, and the remaining four peripheral surfaces are formed as curved surfaces that convex outward rather than as flat surfaces, by winding the conductor wire 61 around the jig to form the curve of the coil 60. This forming method allows the curve of the coil 60 to be formed accurately and easily.

[0031] The coil 60 formed in this manner is a tortoiseshell-shaped (hexagonal) coil 60, and as shown in Figure 2, on both the outer surface 60A side and the inner surface 60B side, the conductor 61 has a parallel portion 62 extending parallel to the axis (center C) of the rotating shaft 20, a hypotenuse portion 63 connected to one end of the parallel portion 62, and a hypotenuse portion 64 connected to the other end of the parallel portion 62.

[0032] As shown in Figure 5, the conductor 61 of each oblique side portion 63, 64 is tangent at a predetermined angle θ to a plane perpendicular to the extension direction of the parallel portion 62 at the end of the coil 60 in the longitudinal direction along the parallel portion 62 (axial direction of the center C).

[0033] That is, at the longitudinal end of the coil 60, the angle formed by the tangent to the curve drawn from the vertex of the hexagon where one ends of the wires 61 of the two adjacent hypotenuses 63, 63 (hypotenuses 63a, 63b) are connected (the tangent to the hypotenuses 63a, 63b) and a plane perpendicular to the axis of the center C, and the angle formed by the tangent to the curve drawn from the vertex of the hexagon where one ends of the wires 61 of the two adjacent hypotenuses 64, 64 (hypotenuses 64a, 64b) are connected (the tangent to the hypotenuses 64a, 64b) and a plane perpendicular to the axis of the center C are both angle θ.

[0034] In the following description, this angle θ will be referred to as the tangent angle θ of the oblique sides 63 and 64. Note that in Fig. 5, the tangent angle θ is drawn only on the left side of the center C on the paper, but it also exists on the right side of the center C so as to be symmetrical with respect to the center C as an axis.

[0035] 3B , when it is necessary to distinguish between the parallel portion 62 on the outer peripheral surface 60A of the coil 60 and the parallel portion 62 on the inner peripheral surface 60B, the parallel portion 62 on the outer peripheral surface 60A is referred to as the parallel portion 62a, and the parallel portion 62 on the inner peripheral surface 60B is referred to as the parallel portion 62b. Similarly, when it is necessary to distinguish between the oblique side portions 63, 64 on the outer peripheral surface 60A of the coil 60 and the oblique side portions 63, 64 on the inner peripheral surface 60B, the oblique side portions 63, 64 on the outer peripheral surface 60A are referred to as the oblique side portions 63a, 64a, and the oblique side portions 63, 64 on the inner peripheral surface 60B are referred to as the oblique side portions 63b, 64b.

[0036] 4 is a diagram schematically illustrating the positional relationship between the magnet 30 and the hexagonal shape of one turn of the coil 60. For example, as shown in FIG. 4, the magnet 30 in the coreless motor 100 of this embodiment is formed with one north pole 30N and one south pole 30S on either side of the axis of the center C. 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] 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 a trigonometric function, where the magnetic force of the magnet 30 is greatest at the center of the north pole 30N and the center of the south pole 30S. FIG. 7 is a schematic diagram showing the total length L0 of the coil 60 along the axial direction of the center C and the length L1 of the parallel portion 62.

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

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

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

[0041] In addition, in the coreless motor 100, the ratio (length ratio) L1 / L0 of the length L1 of the parallel portion 62 to the total length L0 along the axial direction of the center C of the coil 60 as shown in Figure 7 is set to, for example, a range of 0.25 (25[%]) or more and 0.75 (75[%]) or less.

[0042] Here, the maximum torque T that the coreless motor 100 outputs 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 * sin θi (1) In equation (1), B represents the magnetic flux from the magnet 30, I represents the current flowing through the coil 60, r represents the radius of the coil 60 (the dimension along the radial direction R), L represents the length of the coil 60 (the dimension along the center C direction), and θi represents the inclination angle of the conductor 61 in the coil 60 with respect to a plane perpendicular to the center C direction (90 degrees at the parallel portion 62, and changes from θ degrees at the upper oblique side portion 63 and the lower oblique side portion 64).

[0044] In other words, the larger the area of ​​the shaded region in Fig. 5, the greater the maximum torque T that can be output by coreless motor 100. Therefore, in coreless motor 100 of this embodiment, coil 60 has a larger area of ​​the shaded region in Fig. 5 than a coil having straight hypotenuses 63, 64 indicated by the two-dot chain lines in Fig. 3C, and therefore the magnetic flux acting on coil 60 as a whole increases, making it possible to increase the maximum torque T that can be output, which is a characteristic of coreless motor 100.

[0045] Furthermore, as the tangent angle θ of the coil 60 shown in FIG. 5 decreases, the area of ​​the shaded region can be increased, and the maximum torque T output by the coreless motor 100 can be increased. However, in this case, the cross-sectional area of ​​the conductor 61 (copper wire) at the longitudinal ends of the coil 60, the oblique sides 63 and 64, taken along a plane perpendicular to the parallel portion 62, increases as the tangent angle θ decreases, as shown in Table 1 and FIG. 8. The specific values ​​of the cross-sectional area of ​​the conductor 61 shown in Table 1 and FIG. 8 are examples in which 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 portion 62, taken along a plane perpendicular to the parallel portion 62, is 0.0078 mm. ２ ]. FIG. 8 is a graph of Table 1.

[0046]

[0047] 8 , in the coreless motor 100, the tangent angle θ is preferably set to a range of 15 degrees or greater where the cross-sectional area of ​​the conductor 61 at the oblique sides 63 and 64 does not increase abruptly as the tangent angle θ decreases, i.e., where the space factor at the parallel portion 62 does not fall below approximately 30%, i.e., where the cross-sectional area of ​​the conductor 61 at the oblique sides 63 and 64 does not exceed three times the cross-sectional area of ​​the conductor 61 at the parallel portion 62. In particular, the tangent angle θ is preferably set to a range of 20 degrees or greater where the space factor of the conductor 61 at the parallel portion 62 and the thickness at the longitudinal end of the coil 60 fall within a practical range.

[0048] Furthermore, the maximum torque T output by the coreless motor 100 drops to an impractical value when the tangent angle θ of the oblique sides 63, 64 exceeds 50 degrees. Therefore, from the perspective of keeping the maximum torque T output by the coreless motor 100 within a practical range, it is preferable that the tangent angle θ be 50 degrees or less, and even more preferable.

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

[0050] In the coreless motor 100 of this embodiment, 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 varied from 0.95 (95%) to 1.25 (125%). 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 varied from 0.25 (25%) to 0.45 (45%). Tables 2 to 5 and Figures 9 to 12 show the maximum torques output by one turn of the wire 61 of the coil 60 of the coreless motor 100. Note that Figures 9 to 12 are graphs of Tables 2 to 5, respectively.

[0051]

[0052]

[0053]

[0054]

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

[0056]

[0057]

[0058]

[0059]

[0060]

[0061] According to the graphs shown 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; and when the angular pitch ratio β / α is in the range of greater than 1.00 (100[%]) to 1.10 (110[%]), the maximum torque T output by the coreless motor 100 can be increased compared to when the angular pitch ratio β / α is 1.00 (100[%]). Furthermore, the greater 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, it is preferable that the tangent angle θ of the coreless motor 100 of this embodiment be in the range of 15 degrees or more and 50 degrees or less. In particular, when taking into account the graph shown in Figure 8 above, it is preferable that the tangent angle θ be 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 at the oblique sides 63 and 64.

[0063] Furthermore, according to the graphs shown in Figures 9 to 12, in order to increase the maximum torque T, in the coreless motor 100 of this embodiment, in addition to the range of the tangent angle θ described above, it is preferable that the angular pitch ratio β / α be in the range of more than 1.00 (100%]) to 1.10 (110%]) or less, and in particular, it is preferable that the angular pitch ratio β / α be 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 tangent angle θ and the range of the angular 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 it is particularly preferable that the length ratio L1 / L0 be in the range of 0.25 (25%]) or more and 0.45 (45%]) or less.

[0065] As described above, in the coreless motor 100 of this embodiment, when the tangent angle θ is in the range of 15 degrees or more and 50 degrees or less, and in addition, 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, as shown in FIG. 9, for example, when the tangent angle θ is 38.4 degrees and the length ratio L1 / L0 is 0.25 (25%), the coreless motor 100 can obtain an output that exceeds the maximum torque T when the angular pitch ratio β / α is 1.00 (100%), even if the angular pitch ratio β / α is in the range from over 1.00 (100%) to 1.25 (125%), that is, even if the upper limit of the angular pitch ratio β / α is raised from 1.10 (110%) to 1.25 (125%).

[0067] Furthermore, as shown in Figures 9 to 11 above, when the tangent angle θ is 38.4 degrees, 32.0 degrees, or 25.6 degrees, the coreless motor 100 can 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 in the range from over 1.00 (100%) to 1.15 (115%), that is, even when the upper limit of the angular pitch ratio β / α is raised from 1.10 (110%) to 1.15 (115%).

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

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

[0070] In the coreless motor 100 of this embodiment, the greater the length ratio L1 / L0, the greater the maximum torque T that can be output. However, as the length ratio L1 / L0 increases, the cross-sectional area of ​​the conductor 61 at the aforementioned oblique side portions 63 and 64 increases, and the space factor of the conductor 61 at the parallel portion 62 decreases.

[0071] If the space factor of the conductor 61 in the parallel portion 62 becomes smaller than a predetermined value, the strength of the parallel portion 62 will decrease, and the centrifugal force acting when the coil 60 rotates around the center C will deform the coil 60, which may cause the coil 60 to come into contact with the housing 10. For this reason, the coil 60 needs to have a strength sufficient to prevent it from deforming at the rated rotation of the coreless motor 100.

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

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

[0074] As described above, the coreless motor 100 of this embodiment has a tangent angle θ set in the range of 15 degrees or more and 50 degrees or less, 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 or more and 0.75 or less.

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

[0076] The coreless motor 100 of this embodiment, in which the tangent angle θ, angular pitch ratio β / α, and length ratio L1 / L0 are each set as described above, is a practical coreless motor with a large maximum output torque T.

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

[0078] The coreless motor 100 of the above-described embodiment is an outer rotor type coreless motor in which the coil 60 is arranged outside the magnet 30, but 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 peripheral surface of the magnet 30 is fixed to the inner peripheral surface of the case 11, for example.

[0079] The magnet 30 of the coreless motor 100 in the above-described embodiment has one north pole 30N and one south pole 30S, but the magnet of the coreless motor according to the present invention may have two north poles 30N and two south poles 30S, or may have more magnetic poles.

Claims

1. (Deleted)

2. A rotating shaft, A coil formed in a cylindrical shape by winding a conducting wire and rotating integrally with the rotating shaft, A cylindrical magnet disposed inside or outside the cylindrical shape of the coil, and One turn of the coil is formed in a hexagonal shape having a parallel portion extending parallel to the axial direction of the rotating shaft and two hypotenuse portions connected to both ends of the parallel portion and inclined with respect to a plane perpendicular to the axial direction, The hypotenuse portion is formed in a curved shape that protrudes from the inside to the outside of the one turn of the coil, A coreless motor in which a tangent angle formed by a tangent line of the hypotenuse portion drawn from a vertex connecting one ends of two adjacent hypotenuse portions in the one turn of the coil and a plane perpendicular to the axial direction is set in a range of 20 [degrees] or more and 35 [degrees] or less.

3. A rotating shaft, A coil formed in a cylindrical shape by winding a conducting wire and rotating integrally with the rotating shaft, A cylindrical magnet disposed inside or outside the cylindrical shape of the coil, and One turn of the coil is formed in a hexagonal shape having a parallel portion extending parallel to the axial direction of the rotating shaft and two hypotenuse portions connected to both ends of the parallel portion and inclined with respect to a plane perpendicular to the axial direction, The hypotenuse portion is formed in a curved shape that protrudes from the inside to the outside of the one turn of the coil, A tangent angle formed by a tangent line of the hypotenuse portion drawn from a vertex connecting one ends of two adjacent hypotenuse portions in the one turn of the coil and a plane perpendicular to the axial direction is set in a range of 15 [degrees] or more and 50 [degrees] or less, A coreless motor in which a ratio β / α of an angular interval β between two parallel portions in the one turn of the coil to an angular interval α between magnetic poles of the magnet is set in a range exceeding 1.00 and equal to or less than 1.

25.

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

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

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

7. A rotating shaft, A coil formed in a cylindrical shape by winding a conducting wire and rotating integrally with the rotating shaft, A cylindrical magnet disposed inside or outside the cylindrical shape of the coil, and comprising: One turn of the coil is formed in a hexagonal shape having a parallel portion extending parallel to the axial direction of the rotating shaft and two hypotenuse portions connected to both ends of the parallel portion and inclined with respect to a plane orthogonal to the axial direction, The hypotenuse portion is formed in a curved shape that protrudes from the inside to the outside of one turn of the coil, A tangent angle, which is an angle formed by a tangent line of the hypotenuse portion drawn from a vertex connecting one ends of two adjacent hypotenuse portions in one turn of the coil and a plane orthogonal to the axial direction, is set in a range of 15 [degrees] or more and 50 [degrees] or less, A ratio β / α of an angular interval β between two parallel portions in one turn of the coil to an angular interval α between magnetic poles of the magnet is set in a range exceeding 1.00 and being 1.25 or less, The coreless motor, wherein a ratio L1 / L0 of a length L1 of the parallel portion to a total length L0 of one turn of the coil along the axial direction is set in a range of 0.25 or more and 0.75 or less.

8. A rotating shaft, A coil formed in a cylindrical shape by winding a conducting wire and rotating integrally with the rotating shaft, A cylindrical magnet disposed inside or outside the cylindrical shape of the coil, and comprising: One turn of the coil is formed in a hexagonal shape having a parallel portion extending parallel to the axial direction of the rotating shaft and two hypotenuse portions connected to both ends of the parallel portion and inclined with respect to a plane orthogonal to the axial direction, The hypotenuse portion is formed in a curved shape that protrudes from the inside to the outside of one turn of the coil, A tangent angle, which is an angle formed by a tangent line of the hypotenuse portion drawn from a vertex connecting one ends of two adjacent hypotenuse portions in one turn of the coil and a plane orthogonal to the axial direction, is set in a range of 20 [degrees] or more and 35 [degrees] or less, A ratio β / α of an angular interval β between two parallel portions in one turn of the coil to an angular interval α between magnetic poles of the magnet is set in a range of 1.05 or more and 1.10 or less. A coreless motor in which the ratio L1 / L0 of the length L1 of the parallel portion to the total length L0 of one turn of the coil along the axial direction is set in a range of 0.25 or more and 0.45 or less.