Coreless motor

Abstract

In order to improve motor characteristics, a coreless motor (100) is provided with a rotating shaft (20), a coil (60) formed in a cylindrical shape by winding a wire (61) and rotating integrally with the rotating shaft (20), and a cylindrical magnet (30) disposed on the inner side of the cylindrical shape of the coil (60). A single turn of the coil (60) is formed in a hexagonal shape having a parallel portion (62) parallel to the axial direction (center C direction) of the rotating shaft (20) and two beveled portions (63, 64) inclined with respect to a plane perpendicular to the center C direction and connected to both ends of the parallel portion (62), the beveled portions (63, 64) being formed in a curved shape protruding from the inner side of the single turn of the coil (60) toward the outer side, and the beveled portions (63, 64) being connected to both ends of the parallel portion (62). An angle (theta) between a tangent line of the bevel edge portion (63) and a tangent line of a plane perpendicular to the rotating shaft (20) is set in a range from 15 degrees to 50 degrees, and the tangent line of the bevel edge portion (63) is led out from a top point connecting one ends of two adjacent bevel edge portions (63, 63) of a single turn of the coil (60).

Description

Technical Field

[0001] The invention relates to a coreless motor. Background Art

[0002] In a coreless motor, the coil has no iron core, and the rotor is formed solely by winding wire. One method for winding the wire that forms the coil is to form it into a hexagonal shape (tortoise shell shape). This tortoise shell winding method involves, for example, winding the wire circumferentially around the outer surface of a hexagonal prism while slightly offsetting it in the axial direction to form a hexagonal spiral coil element. The hexagonal prism is then pulled out of the coil element in the axial direction, resulting in a hexagonal spiral coil element formed solely from the wire.

[0003] Then, the sides corresponding to the mutually facing faces of the hexagonal prism are crushed into a planar shape so as to move in opposite directions along the axial direction of the hexagonal prism. The resulting planar coil elements are connected and the axial ends are connected to each other, thereby forming a cylindrical coil.

[0004] The outer and inner surfaces of the cylindrical coil each have a parallel portion where the conductive wire is parallel to the axis of the cylinder, and two oblique portions connected to the parallel portion where the conductive wire is inclined relative to a plane perpendicular to the cylinder axis. One proposal involves forming the oblique portions into arc-shaped curves to increase the magnetic flux passing through them (see, for example, Patent Document 1).

[0005] Furthermore, there has been proposed a method of winding a conductive wire into a quadrilateral rather than a hexagon (tortoise shell shape), in which the oblique sides of a coil consisting only of oblique sides without parallel parts are formed into an arc shape (see, for example, Patent Document 2).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-054026

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 55-023788 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] The coils disclosed in the above-mentioned prior art documents increase the amount of magnetic flux passing therethrough by forming the oblique side portions into a curved shape, but the practical shape of the curved oblique side portions is not specifically defined.

[0012] The present invention has been made in view of the above circumstances, and an object thereof is to provide a coreless motor in which the curve of the oblique side of a hexagonal (tortoise-shell-shaped) coil is specifically defined in a practical shape in order to improve the characteristics of the motor.

[0013] Means used to solve problems

[0014] The present invention is a coreless motor comprising: a rotating shaft; a coil formed of a conducting wire wound into a cylindrical shape, which rotates integrally with the rotating shaft; and a cylindrical magnet disposed inside or outside the cylindrical shape of the coil. A single turn of the coil is formed into a hexagon having a parallel portion and two oblique portions, the parallel portion extending parallel to the axial direction of the rotating shaft, the two oblique portions being inclined relative to a plane perpendicular to the axial direction and connected to both ends of the parallel portion, the oblique portions being formed into a curved shape convex from the inside toward the outside of the single turn of the coil, the angle formed between a tangent of the oblique portion and a plane perpendicular to the axial direction, i.e., a tangent angle, being set within a range of 15 degrees to 50 degrees, and the tangent of the oblique portion being drawn from a vertex connecting one end of two adjacent oblique portions of the single turn of the coil.

[0015] Effects of the Invention

[0016] The coreless motor of the present invention specifically defines a practical shape of the curve of the oblique side portion of the hexagonal (tortoise shell-shaped) coil, thereby exhibiting excellent motor characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a cross-sectional view showing a longitudinal section including the center C of the rotating shaft of the coreless motor according to the first embodiment.

[0018] Figure 2 It shows Figure 1 Side view of the coils of a coreless motor is shown.

[0019] Figure 3A It shows the manufacturing Figure 2 Schematic diagram of the coil process 1 is shown.

[0020] Figure 3B It shows the manufacturing Figure 2 Schematic diagram of step 2 of the coil is shown.

[0021] Figure 3C It shows the manufacturing Figure 2 Schematic diagram of step 3 of the coil is shown.

[0022] Figure 4 This is a diagram schematically showing the positional relationship between the magnet and the hexagonal shape of a single turn of the coil.

[0023] Figure 5 Schematic diagram showing the tangent angle θ, which is an angle formed between a tangent line of the oblique side portion of the coil and a plane perpendicular to the parallel portion.

[0024] Figure 6This is a schematic diagram showing the magnitude relationship between the pole pitch and coil pitch of a coreless motor.

[0025] Figure 7 Schematic diagram showing the total length of the coil in the axial direction along the center C and the length of the parallel portion.

[0026] Figure 8 Graph showing the relationship between the coil tangent angle θ and the cross-sectional area of ​​the copper wire at a plane perpendicular to the parallel portion.

[0027] Figure 9 This graph shows the maximum torque output by a single turn of the wire of the coil when the ratio of the coil pitch to the pole pitch (as an example, 180 (°)) is 0.95, 1.00, 1.05, 1.10, and 1.25 (171, 180, 189, 198, and 225 (°)) in each coil with a tangent angle set to 38.4 (°) and 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.

[0028] Figure 10 This graph shows the maximum torque output by a single turn of the wire of the coil when the ratio of the coil pitch to the pole pitch (as an example, 180 (°)) is 0.95, 1.00, 1.05, 1.10, and 1.25 (171, 180, 189, 198, and 225 (°)) in each coil with a tangent angle set to 32.0 (°) and 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.

[0029] Figure 11 This graph shows the maximum torque output by a single turn of the wire of the coil when the ratio of the coil pitch to the pole pitch (as an example, 180(°)) is 0.95, 1.00, 1.05, 1.10, and 1.25 (171, 180, 189, 198, and 225(°)) in each coil with a tangent angle set to 25.6(°) and 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.

[0030] Figure 12 This graph shows the maximum torque output by a single turn of the wire of the coil when the ratio of the coil pitch to the pole pitch (as an example, 180 (°)) is 0.95, 1.00, 1.05, 1.10, and 1.25 (171, 180, 189, 198, and 225 (°)) in each coil with a tangent angle set to 15.0 (°) and 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.

[0031] Figure 13 This graph shows the maximum torque output by a single turn of the wire of the coil when the tangent angle is 38.4, 32.0, 25.6, and 15.0 (°) for each coil in which the ratio of the coil pitch to the pole pitch (as an example, 180 (°)) is set to 0.95 (171 (°)) 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.

[0032] Figure 14 This graph shows the maximum torque output by a single turn of the wire of the coil when the tangent angle is 38.4, 32.0, 25.6, and 15.0 (°) for each coil in which the ratio of the coil pitch to the pole pitch (as an example, 180 (°)) is set to 1.00 (180 (°)) 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.

[0033] Figure 15 This graph shows the maximum torque output by a single turn of the wire of the coil when the tangent angle is 38.4, 32.0, 25.6, and 15.0 (°) for each coil in which the ratio of the coil pitch to the pole pitch (as an example, 180 (°)) is set to 1.05 (189 (°)) 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.

[0034] Figure 16 This graph shows the maximum torque output by a single turn of the wire in each coil when the tangent angle is 38.4, 32.0, 25.6, and 15.0°, for each coil in which the ratio of the coil pitch to the pole pitch (as an example, 180°) is set to 1.10 (198°) 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.

[0035] Figure 17 This graph shows the maximum torque output by a single turn of the wire of the coil when the tangent angle is 38.4, 32.0, 25.6, and 15.0 (°) for each coil in which the ratio of the coil pitch to the pole pitch (as an example, 180 (°)) is set to 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. DETAILED DESCRIPTION

[0036] Embodiments of the coreless motor according to the present invention will be described below using the drawings.

[0037] Figure 1 2 is a cross-sectional view showing a longitudinal section of the coreless motor 100 including the center C of the rotating shaft 20. Figure 2 It shows Figure 1 The three-dimensional view of the coil 60 of the coreless motor 100 is shown. Figure 3A 、 3B 3C is a schematic diagram showing a process of manufacturing the coil 60. The coreless motor 100 is one embodiment of the coreless motor of the present invention.

[0038] like Figure 1 As shown, the coreless motor 100 includes a rotating shaft 20 , a coil 60 , a commutator 50 , a magnet 30 , a brush 40 , and a housing 10 .

[0039] The housing 10 is formed into a hollow cylindrical shape with both ends closed. The hollow interior of the housing 10 houses the rotating shaft 20, coil 60, commutator 50, magnet 30, and brush 40, with both ends of the rotating shaft 20 protruding outside the housing 10. The housing 10 includes a case 11 and a brush holder 12.

[0040] The housing 11 is cylindrical with one end closed. The housing 11 is formed, for example, from a soft magnetic material such as metal. Alternatively, the housing 11 may be formed from multiple components. The brush holder 12 is generally circular, with the open end of the housing 11 closed. The brush holder 12 is formed, for example, from resin. The brush holder 12 includes a connecting member (not shown) for connecting a conductor to an external power source, and a brush 40 electrically connected to the connecting member.

[0041] A rotating shaft 20 is disposed at the center C of the cylindrical axis of the housing 10, passing through the housing 10 and 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.

[0042] like Figure 2 As shown, the coil 60 is made of a wire 61 (refer to Figure 3A 、 3B ) is wound into a cylindrical shape. The coil 60 rotates integrally with the rotating shaft 20 about the center C of the rotating shaft 20. The coil 60 is formed by a plurality of coil elements wound around the conductive wire 61. The outer peripheral surface 60A of the coil 60 is formed into a cylindrical shape and does not contact the inner peripheral surface 11B of the housing 11. Details of the coil 60 will be described later.

[0043] The commutator 50 is formed into a disk-like shape with a boss at its center, through which the rotating shaft 20 passes. The outer periphery of the disk of the commutator 50 is bonded to the inner periphery of the end of the cylindrical coil 60 near the brush holder 12 with an adhesive, thereby integrating the commutator 50 with the coil 60. The commutator 50 is integrally connected to the rotating shaft 20 that passes through the boss, thereby rotating together with the rotating shaft 20 about the center C.

[0044] The commutator 50 has terminals 61a and 61b of the conductor wires 61 of the plurality of coil elements constituting the coil 60 (see Figure 2 、 3A 3B) An electrically connected conductive member, which extends to the outer peripheral surface of the boss and contacts the brush 40 provided on the brush holder 12.

[0045] Magnet 30 is arranged inside the cylinder of coil 60 so as not to contact inner circumferential surface 60B of coil 60. Magnet 30 is formed into a cylindrical shape with center C as its axis. Outer circumferential surface 30A of magnet 30 is formed so as not to contact inner circumferential surface 60B of coil 60. Inner circumferential surface 30B of magnet 30 is fixed to the outer circumferential surface of cylindrical support member 28, which is fixed to housing 11.

[0046] Thus, the magnet 30 is indirectly fixed to the housing 11 and does not move relative to the housing 11. Bearings 25 are provided inside the support member 28 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.

[0047] Next, the details of the coil 60 will be described. In the coil 60, the conductive wires 61 are basically bonded to each other with an adhesive, and there is no core such as an iron core. Therefore, the mass of the coil 60 is lighter than that of a coil having a core.

[0048] like Figure 3A As shown, the coil 60 is formed by winding a conductive wire 61 (e.g., a copper wire) around the outer peripheral surface of a winding fixture 500 having a hexagonal cross-section, such as a hexagonal prism. However, at this time, for each winding turn (one turn of the outer peripheral surface of the hexagonal prism), the position of the wound conductive wire 61 is slightly offset in the axial direction of the hexagonal prism, thereby forming a hexagonal spiral coil 60 as a whole in such a way that a single turn of the coil 60 is hexagonal (tortoise shell shape) when projected in the axial direction.

[0049] In addition, Figure 3A 、 3BIn the figure, the hexagons formed by the wires 61 are recorded as being independent of each other. This is to simplify the description of the figure. In fact, for the wires 61 recorded by these multiple hexagons, the two ends of the single-turn wire 61 of each hexagon are respectively connected to the ends of the single-turn wire 61 of the adjacent hexagon to form a spiral. The wire 61 formed in the spiral has two ends 61a and 61b.

[0050] By pulling the winding jig 500 out of the hexagonal spiral coil 60 formed in this way in the axial direction, the hexagonal spiral coil 60 formed only by the conductive wire 61 is obtained. Then, the sides of the coil 60 corresponding to the mutually facing surfaces of the hexagonal prism of the winding jig 500 are moved in opposite directions along the axial direction of the hexagonal prism ( Figure 3A (as shown by “→”) moves, forming a crushed Figure 3B A planar coil 60 is shown.

[0051] The single-turn conductor 61 of the coil 60 has a tortoise shell shape (hexagonal shape) corresponding to the cross-sectional shape of the winding jig 500. Figure 3B As shown, this tortoise shell shape is a shape in which a conductor 61 has a parallel portion 62 extending parallel to the axis (center C) of the rotating shaft 20, and two oblique portions 63 and 64 connected to the ends of the parallel portion 62. The conductor 61 of the oblique portions 63 and 64 extends linearly in a direction inclined at a predetermined angle relative to a plane perpendicular to the center C. The angle of inclination of the oblique portion 63 and the angle of inclination of the oblique portion 64 are different in direction, but the absolute value is the same.

[0052] Afterwards, to make Figure 3C The straight oblique sides 63 and 64 shown by the double-dashed lines are projected from the inner side of the single turn (hexagon) of the coil 60 toward the outer side. Figure 3B The coil 60 shown is deformed to form Figure 3C The coil 60 of this embodiment has a curved shape that is convex outward, as shown by the solid line. In the coil 60 of this embodiment, the curved shape is, for example, a circular arc. However, in the coreless motor of the present invention, the curved shape of the coil is not limited to a circular arc. For example, the curved shape of the coil may be an elliptical arc, a parabola, or a plurality of interconnected straight lines that approximate these curves (circular arcs, elliptical arcs, parabolas).

[0053] Will Figure 3C The coil 60 of the shape shown is used as a coil element, and a plurality of the coil elements are connected in the axial direction of the aforementioned hexagonal prism, with one side 60A of the coil element formed into a planar shape being the outward surface (outer peripheral surface) and the other side 60B being the inward surface (inner peripheral surface). Figure 3B The center C shown connects the axial ends to each other, thus forming Figure 2The cylindrical coil 60 is shown. The method of forming the curve of the coil 60 is not limited to the above method.

[0054] For example, instead of the hexagonal winding jig 500, the conductive wire 61 may be wound around a cylindrical winding jig in which two circumferential surfaces corresponding to the parallel portion 62 of the hexagonal prism are formed into flat surfaces, and the other four circumferential surfaces are formed into outwardly convex curved surfaces rather than flat surfaces, thereby forming the curve of the coil 60. This forming method can accurately and easily form the curve of the coil 60.

[0055] The coil 60 formed in this manner is a tortoise shell shaped (hexagonal) coil 60, such as Figure 2 As shown, on the outer circumferential surface 60A side and the inner circumferential surface 60B side of the coil 60, the wire 61 has a parallel portion 62 extending parallel to the axis (center C) of the rotating shaft 20, a bevel portion 63 connected to one end of the parallel portion 62, and a bevel portion 64 connected to the other end of the parallel portion 62.

[0056] like Figure 5 As shown, the ends of the conductive wires 61 of the oblique sides 63 and 64 along the longitudinal direction of the parallel portion 62 of the coil 60 (the axial direction of the center C) contact a surface perpendicular to the extending direction of the parallel portion 62 at a predetermined angle θ.

[0057] That is, at the end portions in the longitudinal direction of the coil 60, the angle formed by the tangent line tangent to the curve (the tangent line of the oblique sides 63a and 63b) drawn from the vertices of the hexagon in which the ends of the conductive wires 61 of the two adjacent oblique sides 63 and 63 (oblique sides 63a and 63b) are connected to each other and the plane perpendicular to the axis of the center C, and the angle formed by the tangent line tangent to the curve (the tangent line of the oblique sides 64a and 64b) drawn from the vertices of the hexagon in which the ends of the conductive wires 61 of the two adjacent oblique sides 64 and 64 (oblique sides 64a and 64b) are connected to each other and the plane perpendicular to the axis of the center C are both angle θ.

[0058] In the following description, this angle θ is referred to as the tangent angle θ of the oblique side portions 63 and 64. Figure 5 In FIG, the tangent angle θ is drawn only on the left side of the center C on the paper, and the right side of the center C also exists in a linearly symmetrical manner with the center C as the axis.

[0059] When it is necessary to distinguish the parallel portion 62 of the outer peripheral surface 60A of the coil 60 from the parallel portion 62 of the inner peripheral surface 60B, as shown in FIG. Figure 3BAs shown, the parallel portion 62 of the outer peripheral surface 60A is designated as the parallel portion 62a, and the parallel portion 62 of the inner peripheral surface 60B is designated as the parallel portion 62b. Similarly, when it is necessary to distinguish between the oblique portions 63 and 64 of the outer peripheral surface 60A and the oblique portions 63 and 64 of the inner peripheral surface 60B of the coil 60, the oblique portions 63 and 64 of the outer peripheral surface 60A are designated as the oblique portions 63a and 64a, and the oblique portions 63 and 64 of the inner peripheral surface 60B are designated as the oblique portions 63b and 64b.

[0060] Figure 4 : is a diagram schematically showing the positional relationship between the magnet 30 and the hexagonal single turn of the coil 60. Figure 4 As shown, the magnet 30 of the coreless motor 100 of this embodiment is formed with one north pole 30N and one south pole 30S, for example, sandwiching the axis of the center C. That is, the magnet 30 is formed so that the north pole 30N and the south pole 30S are arranged at an angular interval (angular pitch) of 180 degrees around the axis of the center C of the magnet 30.

[0061] Figure 6 Schematic diagram showing the magnitude relationship between the pole pitch α and the coil pitch β of the coreless motor 100 , and also showing the magnetic force distribution represented by a trigonometric function where the magnetic force of the magnet 30 is maximum at the center of the north pole 30N and the center of the south pole 30S. Figure 7 Schematic diagram showing the total length L0 of the coil 60 in the axial direction along the center C and the length L1 of the parallel portion 62 .

[0062] like Figure 6 As shown, the center of the north pole 30N (the north pole center) and the center of the south pole 30S (the south pole center) of the magnet 30 are angular positions where the absolute values ​​of the magnetic force distribution of the magnet 30 are respectively 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 pole pitch α.

[0063] The coil 60 of the coreless motor 100 of this embodiment is formed as follows Figure 6 As shown, a single-turn hexagon (refer to Figure 5 ) are arranged at an angular interval (angular pitch) about the axis around the center C of the magnet 30. In the following description, the angular pitch (angular interval) along the circumferential direction D about the axis around the center C between the two parallel portions 62, 62 of the coil 60 is referred to as the coil pitch β.

[0064] In the coreless motor 100 of the present embodiment, as an example, the ratio of the coil pitch β to the pole pitch α of the coil 60 (the angular pitch ratio), β / α, is set within a range of 1.00 (100%) to 1.25 (125%). Furthermore, when the pole pitch α of the magnet 30 of the coreless motor 100 is, for example, 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.

[0065] In addition, as an example, in the coreless motor 100, the coil 60 Figure 7 The ratio (length ratio) L1 / L0 of the length L1 of the parallel portion 62 to the total length L0 in the axial direction along the center C is set in the range of 0.25 (25%) to 0.75 (75%).

[0066] Here, in the magnetic field of the magnet 30 , the maximum torque T output by the coreless motor 100 is given by the following formula (1) due to the magnetic force acting on the wire 61 of the coil 60 .

[0067] T=2×B×I×r×L×sinθi (1)

[0068] In formula (1), B represents the magnetic flux of 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 is the angle at which the conductor 61 of the coil 60 is inclined relative to the plane perpendicular to the center C direction (90 (degrees) at the parallel portion 62, and changes from θ (degrees) at the upper oblique portion 63 and the lower oblique portion 64).

[0069] Right now, Figure 5 The larger the area of ​​the area indicated by the diagonal lines in FIG, the larger the maximum torque T output by the coreless motor 100. Therefore, the coil 60 of the coreless motor 100 of this embodiment is different from the coil 60 having Figure 3C Compared with the coils of the oblique sides 63 and 64 of the straight line shown by the double-dashed line, Figure 5 Since the area of ​​the shaded portion shown increases, the magnetic flux acting on the coil 60 as a whole increases, and the maximum torque T outputted as a characteristic of the coreless motor 100 can be increased.

[0070] In addition, with the Figure 5The tangent angle θ of the coil 60 shown in FIG. 6 is reduced, and the area of ​​the region indicated by the oblique lines 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 conductive wire 61 (copper wire) formed by the surface perpendicular to the parallel portion 62 at the ends of the oblique sides 63 and 64 in the longitudinal direction of the coil 60 is as shown in Table 1 and FIG. Figure 8 As shown in Table 1, the tangent angle θ increases as it decreases. Figure 8 The specific value of the cross-sectional area of ​​the conductor 61 shown is an example in which the diameter of the conductor 61 is 0.1 (mm). Therefore, in this example, the cross-sectional area of ​​the conductor 61 formed by the plane perpendicular to the parallel portion 62 at the parallel portion 62 is 0.0078 (mm 2 ).also, Figure 8 This is a graph showing Table 1.

[0071] [Table 1]

[0072] Tangent angle 15 25 35 45 55 Cross-sectional area of ​​copper wire 0.030 0.019 0.014 0.011 0.010

[0073] Furthermore, if the cross-sectional area of ​​the conductor 61 at the oblique side portions 63 and 64 increases, it becomes difficult for the conductors 61 to be arranged one above the other. Therefore, the space factor of the conductor 61 at the parallel portion 62 decreases, and the thickness of the end portion of the coil 60 in the longitudinal direction also increases. Figure 8 As shown in the curve diagram, with respect to the decrease in the tangent angle θ, it is preferred that the following specific tangent angle θ be in a range of 15 (degrees) or more, and this specific tangent angle θ is a tangent angle in a range in which the cross-sectional area of ​​the conductor 61 does not increase sharply, that is, the space factor in the parallel portion 62 does not become less than about 30 (%), that is, the cross-sectional area of ​​the conductor 61 in the oblique portions 63 and 64 does not exceed 3 times the cross-sectional area of ​​the conductor 61 in the parallel portion 62. In particular, it is preferred that the tangent angle θ be in a range of 20 (degrees) or more, so that the space factor of the conductor 61 in the parallel portion 62 and the thickness of the end portion of the coil 60 in the longitudinal direction are more practical.

[0074] Furthermore, if the tangent angle θ of the oblique sides 63 and 64 exceeds 50 degrees, the maximum torque T output by the coreless motor 100 decreases to an impractical value. Therefore, to keep the maximum torque T output by the coreless motor 100 within a practical range, the tangent angle θ is preferably 50 degrees or less.

[0075] That is, 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 further preferably 20 degrees or more and 35 degrees or less.

[0076] In the coreless motor 100 of the present 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), respectively. When the ratio of the coil pitch β to the 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 the single turn of the wire 61 of the coil 60 of the coreless motor 100 is shown in Tables 2 to 5 and Tables 2 to 5. Figures 9-12 In addition, Figures 9-12 Tables 2 to 5 are graphed respectively.

[0077] [Table 2]

[0078] Tangent angle: 38.4°

[0079]

[0080] [Table 3]

[0081] Tangent angle: 32.0°

[0082]

[0083] [Table 4]

[0084] Tangent angle: 25.6°

[0085]

[0086] [Table 5]

[0087] Tangent angle: 15°

[0088]

[0089] Furthermore, in the coreless motor 100 of the present embodiment, when the ratio of the coil pitch β to the pole pitch α (angular pitch ratio) β / α is set to 0.95 (95%), 1.00 (100%), 1.05 (105%), 1.10 (110%), and 1.20 (120%), respectively, and when 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 (length ratio) L1 / L0 is changed from 0.25 (25%) to 0.45 (45%), the maximum torques output by the single-turn conductor 61 of the coil 60 of the coreless motor 100 are shown in Tables 6 to 10 and Tables 6 to 11. Figures 13-17 In addition, Figures 13-17 Tables 6 to 10 are graphed respectively.

[0090] [Table 6]

[0091] Pitch: 171° (95%)

[0092]

[0093] [Table 7]

[0094] Pitch: 180°(100%)

[0095]

[0096] [Table 8]

[0097] Pitch: 189° (105%)

[0098]

[0099] [Table 9]

[0100] Pitch: 198° (110%)

[0101]

[0102] [Table 10]

[0103] Pitch: 225°(125%)

[0104]

[0105] according to Figures 9 to 17 As shown in the curve graph, in the coreless motor 100 of this embodiment, the smaller the tangent angle θ is, the larger the maximum torque T output by the coreless motor 100 can be. In addition, by making the angular pitch ratio β / α within the range of greater than 1.00 (100(%)) and less than 1.10 (110(%)), the maximum torque T output by the coreless motor 100 can be increased compared with the case where the angular pitch ratio β / α is 1.00 (100(%)). In addition, the larger the length ratio L1 / L0 is, the larger the maximum torque T output by the coreless motor 100 can be.

[0106] According to the above Figures 13-17 As shown in the graph, in order to increase the maximum torque T, the coreless motor 100 of this embodiment preferably has a tangent angle θ in the range of 15 (degrees) or more and 50 (degrees) or less. In particular, if the aforementioned Figure 8In the graph shown, in order to minimize the increase in the cross-sectional area of ​​the conductive wire 61 at the oblique sides 63 and 64 , the tangent angle θ is preferably within a range of 20 degrees to 35 degrees.

[0107] In addition, according to the above Figures 9-12 As shown in the curve graph, in order to increase the maximum torque T, the coreless motor 100 of this embodiment preferably has an angular pitch ratio β / α in the range of greater than 1.00 (100(%)) and less than 1.10 (110(%)) in addition to the range of the tangent angle θ mentioned above. In particular, it is preferred that the range in which the maximum torque T is maximized is the angular pitch ratio β / α in the range of greater than 1.05 (105(%)) and less than 1.10 (110(%)).

[0108] Moreover, in the coreless motor 100 of this embodiment, in addition to the range of the above-mentioned tangent angle θ and the range of the angular pitch ratio β / α, it is also preferred that the length ratio L1 / L0 is in the range of 0.25 (25 (%)) or more and 0.75 (75 (%)) or less, and in particular, the length ratio L1 / L0 is in the range of 0.25 (25 (%)) or more and 0.45 (45 (%)) or less.

[0109] In addition, as described above, in the coreless motor 100 of this embodiment, the tangent angle θ is in the range of greater than 15 (degrees) and less than 50 (degrees). In addition, when the length ratio L1 / L0 is greater than 0.25 (25 (%)) and less than 0.75 (75 (%)), the angular pitch ratio β / α is preferably greater than 1.00 (100 (%)) and less than 1.10 (110 (%)).

[0110] However, in the coreless motor 100, for example, Figure 9 As shown, when the tangent angle θ is 38.4 (degrees) and the length ratio L1 / L0 is 0.25 (25 (%)), even if the angular pitch ratio β / α is in the range of 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 (%)), an output of the maximum torque T exceeding that when the angular pitch ratio β / α is 1.00 (100 (%)) can be obtained.

[0111] In addition, for example, Figures 9-11As shown, in the coreless motor 100, when the tangent angle θ is 38.4 (degrees), 32.0 (degrees), and 25.6 (degrees), even if the angular pitch ratio β / α is in the range of 1.00 (100 (%)) to 1.15 (115 (%)), that is, when the upper limit of the angular pitch ratio β / α is increased from 1.10 (110 (%)) to 1.15 (115 (%)), the maximum torque T exceeding that when the angular pitch ratio β / α is 1.00 (100 (%)) can be obtained.

[0112] Therefore, in the coreless motor 100 , even when the tangent angle θ is 38.4 degrees and the length ratio L1 / L0 is 0.25 (25%), the angular pitch ratio β / α can be set to a range from 1.00 (100%) to 1.25 (125%).

[0113] In the coreless motor 100 , even 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 of 1.00 (100%) to 1.15 (115%).

[0114] In the coreless motor 100 of this embodiment, the larger the length ratio L1 / L0 is, the greater the maximum torque T output can be. As the length ratio L1 / L0 increases, the cross-sectional area of ​​the conductor 61 in the aforementioned oblique portions 63 and 64 increases, and the space factor of the conductor 61 in the parallel portion 62 decreases.

[0115] Furthermore, if the space factor of the conductive wire 61 in the parallel portion 62 is smaller than a predetermined factor, the strength of the parallel portion 62 decreases, and the coil 60 may deform due to the centrifugal force acting thereon when rotating about the center C, potentially causing contact with the housing 10. Therefore, the coil 60 must be strong enough to prevent deformation at the rated rotation of the coreless motor 100.

[0116] Therefore, in the coreless motor 100 of this embodiment, the upper limit of the length ratio L1 / L0 is 0.75 (75%) to ensure the required strength of the coil 60. In particular, considering the safety factor at rated rotation, and in order to ensure sufficient strength of the coil 60, the upper limit of the length ratio L1 / L0 of the coreless motor 100 is preferably 0.45 (45%).

[0117] In the coreless motor 100 of this embodiment, the lower limit of the coil 60 length ratio L1 / L0 is 0.25 (25%). This is because the coreless motor 100 easily outputs a maximum torque T exceeding the generally required minimum. If the length ratio L1 / L0 is less than 0.25 (25%), it becomes difficult to output a sufficient maximum torque T.

[0118] To summarize, in the coreless motor 100 of this embodiment, the tangent angle θ is set in the range of greater than 15 (degrees) and less than 50 (degrees), the angular pitch ratio β / α is set in the range of greater than 1.00 and less than 1.25, and the length ratio L1 / L0 is set in the range of greater than 0.25 and less than 0.75.

[0119] Moreover, in the coreless motor 100 of this embodiment, it is most preferred that the tangent angle θ is set in the range of greater than 20 (degrees) and less than 35 (degrees), the angular pitch ratio β / α is set in the range of greater than 1.05 and less than 1.10, and the length ratio L1 / L0 is set in the range of greater than 0.25 and less than 0.45.

[0120] The coreless motor 100 of the present embodiment, in which the tangent angle θ, the angular pitch ratio β / α, and the length ratio L1 / L0 are set as described above, becomes a practical coreless motor that outputs a large maximum torque T.

[0121] Furthermore, according to verification results by the applicant of this application, the coreless motor 100 of this embodiment can increase the maximum output torque T by, for example, approximately 10% compared to a conventional coreless motor having a hexagonal (tortoise-shell-shaped) coil with straight oblique sides 63 and 64.

[0122] The coreless motor 100 of the above embodiment is an outer rotor type coreless motor in which the coils 60 are arranged outside the magnets 30. However, the coreless motor of the present invention is not limited to an outer rotor type coreless motor and may also be an inner rotor type coreless motor in which the coils 60 are arranged inside the magnets 30. In the case of an inner rotor type coreless motor, the outer circumferential surface of the magnets 30 is fixed to the inner circumferential surface of the housing 11, for example.

[0123] The coreless motor 100 in the above embodiment has one magnet 30 each of the north pole 30N and the south pole 30S. However, the coreless motor of the present invention may have two magnets each of the north pole 30N and the south pole 30S, or may have more magnets than these.

Claims

1. A coreless motor, wherein: have: Axis of rotation, a coil formed by winding a conducting 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; A single turn of the coil is formed into a hexagon having a parallel portion and two oblique portions, the parallel portion extending parallel to the axial direction of the rotating shaft, the two oblique portions being inclined relative to a plane perpendicular to the axial direction and connected to both ends of the parallel portion. The oblique side portion is formed in a curved shape that bulges outward from the inner side of the single turn of the coil. The angle formed by the tangent of the oblique side portion and the plane perpendicular to the axial direction, i.e., the tangent angle, is set in the range of greater than 15 degrees and less than 50 degrees, and the tangent of the oblique side portion is drawn from the vertex connecting one end of the two adjacent oblique side portions of the single turn of the coil.

2. The coreless motor according to claim 1, wherein: The tangent angle is set in a range of 20 degrees to 35 degrees.

3. The coreless motor according to claim 1 or 2, wherein: A ratio β / α of an angular interval β between the two parallel portions of the single turn of the coil and an angular interval α between the magnetic poles of the magnet is set in a range greater than 1.00 and not more than 1.

25.

4. The coreless motor according to claim 1 or 2, wherein: A ratio β / α of an angular interval β between the two parallel portions of the single turn of the coil and an angular interval α between the magnetic poles of the magnet is set in a range of 1.05 to 1.

10.

5. The coreless motor according to claim 1 or 2, wherein: A ratio L1 / L0 of a length L1 of the parallel portion of the single turn of the coil to a total length L0 along the axial direction is set in a range of 0.25 to 0.

75.

6. The coreless motor according to claim 1 or 2, wherein: A ratio L1 / L0 of a length L1 of the parallel portion of the single turn of the coil to a total length L0 along the axial direction is set in a range of 0.25 to 0.

45.

7. A coreless motor, wherein: have: Axis of rotation, a coil formed by winding a conducting 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; A single turn of the coil is formed into a hexagon having a parallel portion and two oblique portions, the parallel portion extending parallel to the axial direction of the rotating shaft, the two oblique portions being inclined relative to a plane perpendicular to the axial direction and connected to both ends of the parallel portion. The oblique side portion is formed in a curved shape that bulges outward from the inner side of the single turn of the coil. The angle formed by the tangent line of the oblique side portion and the plane perpendicular to the axial direction, i.e., the tangent angle, is set in a range of not less than 15 degrees and not more than 50 degrees, and the tangent line of the oblique side portion is drawn from a vertex connecting one ends of two adjacent oblique sides of the single turn of the coil. The ratio β / α of the angular interval β between the two parallel portions of the single turn of the coil and the angular interval α between the magnetic poles of the magnet is set to be greater than 1.00 and less than 1.

25. A ratio L1 / L0 of a length L1 of the parallel portion of the single turn of the coil to a total length L0 along the axial direction is set in a range of 0.25 to 0.

75.

8. A coreless motor, wherein: have: Axis of rotation, a coil formed by winding a conducting 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; A single turn of the coil is formed into a hexagon having a parallel portion and two oblique portions, the parallel portion extending parallel to the axial direction of the rotating shaft, the two oblique portions being inclined relative to a plane perpendicular to the axial direction and connected to both ends of the parallel portion. The oblique side portion is formed in a curved shape that bulges outward from the inner side of the single turn of the coil. The angle formed by the tangent line of the oblique side portion and the plane perpendicular to the axial direction, i.e., the tangent angle, is set in a range of not less than 20 degrees and not more than 35 degrees, and the tangent line of the oblique side portion is drawn from a vertex connecting one ends of two adjacent oblique sides of the single turn of the coil. The ratio β / α of the angular interval β between the two parallel portions of the single turn of the coil and the angular interval α between the magnetic poles of the magnet is set in a range of 1.05 to 1.

10. A ratio L1 / L0 of a length L1 of the parallel portion of the single turn of the coil to a total length L0 along the axial direction is set in a range of 0.25 to 0.45.

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