Coreless motor

Abstract

In order to change the characteristics of a motor without reducing the degree of freedom of design of the motor, 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 or the outer side of the cylindrical shape of the coil (60). For example, the angular interval (beta) around the axis (around the center C) of the rotating shaft (20) between the single-turn wires (61) of the coil (60) (between the two parallel parts (62) and (62)) is set to be different from the angular interval (alpha) around the axis (around the center C) of the rotating shaft (20) between the magnetic poles (30N, 30S) of the magnet (30).

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, formed by the portion arranged on the outer and inner surfaces of the cylinder, each have a parallel portion parallel to the axis of the cylinder and two oblique side portions adjacent to the parallel portion and inclined relative to the axis.

[0005] Generally speaking, the angular spacing around the motor axis between the two parallel portions of the tortoise shell shape of one coil turn is configured to match the angular spacing around the axis of the motor's magnet's magnetic poles. Specifically, for example, if the angular spacing around the axis between the north and south poles of the motor's magnets (hereinafter referred to as the pole pitch) is 180 degrees, the angular spacing around the axis between the two parallel portions of the coil (hereinafter referred to as the coil pitch) is also set to 180 degrees.

[0006] Furthermore, from the perspective of cost and workability in the manufacturing process, coreless motors also have structures in which the angular interval of coil elements and the pole pitch do not coincide with each other (see, for example, Patent Document 1).

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 1-186143 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] Furthermore, when changing various motor characteristics, the dimensions of the coil's parallel portion or the number of coil turns are generally altered. For example, increasing output torque, one of the motor's characteristics, is achieved by lengthening the coil's parallel portion. While increasing rotational speed, another characteristic of the motor, is achieved by reducing the number of coil turns.

[0012] However, in motors, increasing the overall length of the coil to increase the length of the parallel portion of the coil results in a longer overall length of the motor. Alternatively, by changing the angle of the coil's beveled portion without changing the overall length of the coil, the radial thickness of the beveled portion increases, increasing the motor's diameter. Furthermore, reducing the number of coil turns in a motor to increase the rotational speed can reduce the coil's rigidity.

[0013] That is, by changing the characteristics of the motor, the degree of freedom in designing the motor decreases.

[0014] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a coreless motor that can change the characteristics of the motor without reducing the degree of freedom in designing the motor.

[0015] Means used to solve problems

[0016] The present invention provides a coreless motor comprising: a rotating shaft; a coil formed of a conductive 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. The angular spacing β between the conductive wires of a single turn of the coil about the rotating shaft is set to be different from the angular spacing α between the magnetic poles of the magnet about the rotating shaft.

[0017] Effects of the Invention

[0018] According to the coreless motor of the present invention, the characteristics of the motor can be changed without reducing the degree of freedom in designing the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 2 It shows Figure 1 A perspective view of the coils of a coreless motor is shown.

[0021] Figure 3A It shows the manufacturing Figure 2 Schematic diagram of the coil process 1 is shown.

[0022] Figure 3B It shows the manufacturing Figure 2Schematic diagram of step 2 of the coil is shown.

[0023] 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.

[0024] Figure 5 Schematic diagram showing the total axial length of the coil and the length of the parallel portion along the center C of the coil.

[0025] Figure 6 This is a schematic diagram showing the magnitude relationship between the pole pitch and coil pitch of a coreless motor.

[0026] Figure 7 This graph shows the maximum torque output by a single turn of wire in each coil when the ratio of the coil pitch to the pole pitch is 0.95, 1.00, 1.05, 1.10, and 1.25 (95, 100, 105, 110, and 125 (%)) for each coil in which the ratio of the length of the parallel portion of the coil to the total length is set to 0.25, 0.30, 0.35, 0.40, and 0.45 (25, 30, 35, 40, and 45 (%)).

[0027] Figure 8 This is a modified example showing a coil pitch smaller than the pole pitch. Figure 6 Quite a schematic diagram. DETAILED DESCRIPTION

[0028] Embodiments of the coreless motor according to the present invention will be described below using the drawings.

[0029] <Implementation Method 1>

[0030] 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 、 Figure 3B Schematic diagram showing the process of manufacturing the coil 60. The coreless motor 100 is one embodiment (Embodiment 1) of the coreless motor of the present invention.

[0031] 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 .

[0032] 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.

[0033] The housing 11 is cylindrical with one end closed. The housing 11 is formed, for example, from a soft magnetic material. The brush holder 12 is generally disk-shaped, with the open end of the housing 11 closed. The brush holder 12 is formed, for example, from resin. The brush holder 12 is provided with a connecting member (not shown) for connecting a conductor to an external power source, and a brush 40 electrically connected to the connecting member.

[0034] 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.

[0035] 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 a conductive wire 61 (e.g., a copper wire). The outer peripheral surface 60A of the coil 60 is formed into a cylinder and does not contact the inner peripheral surface 11B of the housing 11. Details of the coil 60 will be described later.

[0036] The commutator 50 is formed into a circular plate with a boss at its center, through which the rotating shaft 20 passes. The outer periphery of the commutator 50's disk is bonded to the inner periphery of the end of the cylindrical coil 60 near the brush holder 12 with 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.

[0037] 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 extending to the outer peripheral surface of the boss and contacting the brush 40 provided on the brush holder 12.

[0038] 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.

[0039] 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.

[0040] Next, the details of the coil 60 are described as follows. 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.

[0041] like Figure 3A As shown, as for the coil 60, the conductive wire 61 is wound on the outer peripheral surface of a winding fixture 500 having a hexagonal cross-section, for example, a hexagonal prism, but 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 spiral coil 60 in a manner such that a single turn is hexagonal (tortoise shell shape).

[0042] In addition, Figure 3A 、 3B In 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 connected to the ends of the single-turn wire 61 of other hexagons to form a spiral, and the wire 61 formed in the spiral has two ends 61a and 61b.

[0043] 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 In the middle, as shown by the mark “→”), it moves and forms a Figure 3B A planar coil 60 is shown.

[0044] Will Figure 3B The coil 60 shown is a coil element, and a plurality of the coil elements are connected in the axial direction of the hexagonal prism, with one surface 60A of the coil element being the outward surface (outer peripheral surface) and the other surface 60B being the inward surface (inner peripheral surface). Figure 3B The center C shown connects the axial ends to each other, thus forming Figure 2 The cylindrical coil 60 is shown. In addition, the method of forming the coil 60 is not limited to the above method.

[0045] The coil 60 formed in this manner is a tortoise shell shaped (hexagonal) coil 60, such as Figure 2 As shown, the 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 both ends of the parallel portion 62 on both the outer circumferential surface 60A and the inner circumferential surface 60B of the coil 60. The conductor 61 of the oblique portions 63 and 64 is perpendicular to the plane (such as Figure 3B The single dotted line in FIG extends in the direction of a predetermined angle θ. Figure 3B As shown, the angle θ of the inclination of the oblique side portion 63 and the angle θ of the inclination of the oblique side portion 64 are different in direction, but have the same absolute value.

[0046] In addition, when it is necessary to distinguish the parallel portion 62 on the outer peripheral surface 60A of the coil 60 from the parallel portion 62 on the inner peripheral surface 60B, as shown in FIG. Figure 3B As shown, 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 portions 63 and 64 on the outer peripheral surface 60A of the coil 60 and the oblique portions 63 and 64 on the inner peripheral surface 60B, the oblique portions 63 and 64 on the outer peripheral surface 60A are referred to as the oblique portions 63a and 64a, and the oblique portions 63 and 64 on the inner peripheral surface 60B are referred to as the oblique portions 63b and 64b.

[0047] Figure 4 Schematically shows the positional relationship between the magnet 30 and the hexagonal shape of a single turn of the coil 60. Figure 4 As shown, the magnet 30 of the coreless motor 100 of this embodiment is formed with, for example, one north pole 30N and one south pole 30S, each formed across the axis of the center C. Specifically, 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 α = 180 (degrees) around the axis of the center C of the magnet 30. Figure 4 The center of the north pole 30N (the north pole center) and the center of the south pole 30S (the south pole center) indicated by the dashed line are the angular positions where the absolute value of the magnetic force distribution of the magnet 30 is the largest. In the following description, the angular pitch α between the center of the north pole 30N and the center of the south pole 30S is referred to as the pole pitch α.

[0048] also, Figure 4 The two-dot chain line in shows the boundary between the N pole 30N and the S pole 30S, but the magnet 30 is not structurally separated at the boundary.

[0049] like Figure 4As shown, the coil 60 of the coreless motor 100 of this embodiment is formed so that two hexagonal parallel portions 62, 62 of a single turn are arranged at an angular interval (angular pitch) β about the axis around the center C of the magnet 30. Furthermore, in a single turn of the coil 60, the two parallel portions 62, 62 are the portions with the largest angular interval about the axis around the center C. In the following description, the angular pitch β is referred to as the coil pitch β.

[0050] Figure 5 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. 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 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.

[0051] like Figure 5 As shown, in the coreless motor 100 , the coil 60 is set so that the ratio (length ratio) L1 / L0 of the length L1 of the parallel portion 62 to the total length L0 of the coil 60 along the axial direction of the center C is greater than or equal to 0.25 (25%) and less than or equal to 0.45 (45%).

[0052] Moreover, if Figure 6 As shown, as an example, the coreless motor 100 is formed with an overpitch in which the coil pitch β is greater than the pole pitch α (α < β). Specifically, the coreless motor 100 is configured such that the ratio β / α of the coil pitch β to the pole pitch α is greater than 1. Specifically, β / α is set within a range greater than 1.00 (100%) and less than 1.25 (120%) (1.00 < β / α ≤ 1.25). In this case, as an example, the pole pitch α of the coreless motor 100 is 180 degrees, so the coil pitch β is greater than 180 degrees and less than 225 degrees.

[0053] The maximum torque T output by the coreless motor 100 , which is generated by the magnetic force acting on the conductive wire 61 of the coil 60 in the magnetic field of the magnet 30 , is given by the following formula (1).

[0054] T=2×B×I×rL×sinθ (1)

[0055] 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 θ is the inclination angle of the conductor 61 of the coil 60 relative to the plane perpendicular to the center C direction (90 (degrees) at the parallel portion 62, θ (degrees) at the upper oblique portion 63, and θ (degrees) at the lower oblique portion 64).

[0056] As a result, although the peak value of the magnetic force of the magnet 30 acting on the parallel portion 62 of the long-distance coreless motor 100 is reduced, by increasing the magnetic flux of the oblique portions 63 and 64 at the angular position where the peak value of the magnetic force is located, the magnetic flux acting on the coil 60 as a whole is increased, thereby increasing the maximum torque T of the coreless motor 100.

[0057] Figure 7 It is a graph showing the maximum torque T output by a single turn of the conductive wire 61 of the coil 60 when the ratio L1 / L0 of the length L1 of the parallel portion 62 of the coil 60 to the total length L0 is set to 0.25, 0.30, 0.35, 0.40, 0.45 (25, 30, 35, 40, 45 (%)) and the ratio β / α of the coil pitch β to the pole pitch α is 0.95, 0.10, 1.05, 1.10, 1.25 (95, 100, 105, 110, 125 (%)).

[0058] in, Figure 7 The maximum torque T output by the coil 60 with the oblique sides 63 and 64 formed into a tortoise shell shape with an arc shape is shown. In addition, when the oblique sides 63 and 64 of the coil 60 are formed into a straight tortoise shell shape, the maximum torque T output by the coil is greater than Figure 7 The maximum torque T shown is slightly reduced, but the change in the maximum torque T is proportional to the change in the ratio β / α. Figure 7 The graphs shown are the same.

[0059] exist Figure 7 In the curve diagram shown, the ratio L1 / L0 of the length L1 of the parallel portion 62 of the coreless motor 100 of this embodiment to the total length L0 of the coil 60 is set to 0.25, 0.30, 0.35, 0.40, 0.45 (25, 30, 35, 40, 45 (%)), and the ratio β / α of the coil pitch β to the pole pitch α is set in a range greater than 1.00 (100 (%)) and less than 1.25 (125 (%)).

[0060] The coreless motor 100 of this embodiment is formed with a coil pitch β being larger than the pole pitch α. Figure 7 As shown, in the coreless motor 100 of this embodiment, when the ratio β / α of the coil pitch β to the pole pitch α is greater than 1.00 (100%) and less than 1.15 (115%), the maximum torque T can be increased compared to a coreless motor with a non-long pitch β = α (β / α = 100%). In particular, when the ratio β / α of the coil pitch β to the pole pitch α is greater than 1.05 (105%) and less than 1.10 (110%), the maximum torque T can be maximized. Therefore, in the coreless motor 100, the ratio β / α of the coil pitch β to the pole pitch α is preferably within the above range.

[0061] The reason why the upper limit of the ratio β / α of the coil pitch β to the pole pitch α is 1.25 (125%) is that if the ratio β / α becomes larger than this value, it becomes difficult for the coreless motor 100 to output a sufficient maximum torque T.

[0062] The coreless motor 100 of these present embodiments does not require changes in the size or strength of the coreless motor, such as lengthening the parallel portion 62 of the coil 60 of the coreless motor or increasing the number of turns of the wire of the coil 60. The maximum torque T of the coreless motor 100 can be changed simply by setting the ratio β / α of the coil pitch β to the pole pitch α to be greater than 100 (%).

[0063] Furthermore, by lengthening the coreless motor 100 so that the ratio β / α of the coil pitch β to the pole pitch α is greater than 100%, not only the maximum torque T of the coreless motor 100 but also other characteristics of the coreless motor 100 can be changed.

[0064] Specifically, by making the coreless motor 100 have a long pitch (β / α) greater than 100% of the ratio of the coil pitch β to the pole pitch α, for example, the rotation speed of the coreless motor 100 can be reduced.

[0065] In the above-mentioned coreless motor 100, the magnet 30 has one N pole 30N and one S pole 30S, but the magnet 30 of the coreless motor 100 of this embodiment may also have two N poles 30N and two S poles 30S. In this case, the pole pitch α is 90 (degrees), and based on the conditional expression 1.00<β / α≤1.25 of the ratio of the coil pitch β to the pole pitch α, the coil pitch β can be set to be greater than 90 (degrees) and less than 112.5 (degrees).

[0066] In addition, in this case, in order to increase the maximum torque T, based on the conditional expression of the ratio β / α of the coil pitch β to the pole pitch α of 1.00<β / α≤1.15, the coil pitch β can be set to be greater than 90 (degrees) and less than 103.5 (degrees). In particular, in order to maximize the maximum torque T, based on the conditional expression of the ratio β / α of the coil pitch β to the pole pitch α of 1.05≤β / α≤1.10, the coil pitch β can be set to be greater than 94.5 (degrees) and less than 99 (degrees).

[0067] Similarly, the magnet 30 of the coreless motor 100 of this embodiment can also be formed with n (3≤n) N poles 30N and three S poles 30S. In this case, the pole pitch α is 180 / n (degrees). Based on the conditional expression of the ratio β / α of the coil pitch β to the pole pitch α 1.00<β / α≤1.25, the coil pitch β can be set to be greater than 180 / n (degrees) and less than 225 / n (degrees).

[0068] In addition, in this case, in order to increase the maximum torque T, the coil pitch β can be set to be greater than 180 / n (degrees) and less than 207 / n (degrees) based on the conditional expression of the ratio β / α of the coil pitch β and the pole pitch α of 1.00<β / α≤1.15. In particular, in order to maximize the maximum torque T, the coil pitch β can be set to be greater than 189 / n (degrees) and less than 198 / n (degrees) based on the conditional expression of the ratio β / α of the coil pitch β and the pole pitch α of 1.05≤β / α≤1.10.

[0069] like Figure 7 As shown, for the coreless motor 100 of this embodiment, the larger the length ratio L1 / L0 is, the larger the maximum torque T output can be. As the length ratio L1 / L0 becomes larger, the cross-sectional area of ​​the conductor 61 of the oblique side portions 63 and 64 in the direction perpendicular to the center C becomes larger, resulting in a lower space factor of the conductor 61 of the parallel portion 62.

[0070] 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 during rotation 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.

[0071] 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 is preferably 0.45 (45%).

[0072] In the coreless motor 100 of this embodiment, the lower limit of the length ratio L1 / L0 of the coil 60 is 0.25 (25%). This is because the coreless motor 100 can easily output the generally required minimum maximum torque T. If the length ratio L1 / L0 is less than 0.25 (25%), it is difficult for the coreless motor 100 to output a sufficient maximum torque T.

[0073] Modifications

[0074] Figure 8 The present invention shows a modified example of a short pitch coil in which the coil pitch β is smaller than the pole pitch α (β < α). Figure 6 A comparable schematic diagram. Figure 6 As shown, the coreless motor 100 of the above embodiment is formed with a long pitch in which the coil pitch β is larger than the pole pitch α, but the coreless motor of the present invention is not limited to having a long pitch coil. That is, as an example, Figure 8As shown, a coreless motor according to a modified example of another embodiment of the present invention may be formed with a short pitch in which the coil pitch β is smaller than the pole pitch α (β<α).

[0075] Specifically, in the coreless motor of the modified example, the ratio β / α of the coil pitch β to the pole pitch α is set in a range less than 1.00 (100(%)) (β / α<1.00), for example, it is set in a range greater than 0.90 (90(%)) and less than 1.00 (100(%)) (0.90≤β / α<1.00).

[0076] The coreless motor of the modified example constructed in this way has a short pitch in which the ratio β / α of the coil pitch β to the pole pitch α is less than 1.00 (100(%)). For example, by making the ratio β / α within the range of 0.90 (90(%)) and less than 1.00 (100(%)), the characteristics of the coreless motor can be changed.

[0077] The coreless motor of the modified example is a short-pitch motor in which the ratio β / α of the coil pitch β to the pole pitch α is less than 1.00 (100(%)). For example, by making the ratio β / α greater than 0.90 (90(%)) and less than 1.00 (100(%)), specifically, the rotation speed of the coreless motor can be increased.

[0078] Therefore, when increasing the rotational speed of a coreless motor to increase the rotational speed, conventional coreless motors that do not employ the present invention have responded by reducing the number of turns of the conductive wire 61 of the coil 60. However, reducing the number of turns of the conductive wire 61 of the coil 60 may reduce the rigidity of the coil 60.

[0079] In contrast, in the coreless motor of the modified example, since the number of turns of the conductive wire 61 of the coil 60 is not reduced, the rigidity of the coil 60 is not reduced.

[0080] The coreless motor 100 of the above-described embodiment and modified example is an outer rotor type coreless motor in which the coil 60 is arranged outside the magnet 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 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 the inner circumferential surface of the housing 11, for example.

[0081] The coreless motor of the present invention is not limited to a coreless motor having a tortoise-shell-shaped coil with the oblique sides 63 and 64 of the coil 60 formed into a straight line, but can also be a coreless motor having a tortoise-shell-shaped coil with the oblique sides 63 and 64 of the coil 60 formed into a curved line (such as a circular arc, an elliptical arc, or a parabola).

[0082] The coreless motor of the present invention is not limited to one having coils in a tortoise shell (hexagonal) shape, but may also include coils in other shapes (e.g., rhombus, quadrilateral, circular, or elliptical). Furthermore, in this coreless motor, for example, when the coils are rhombus-shaped, the portions corresponding to the two parallel portions 62, 62 of the coil 60 are two vertices facing each other in the direction of the axis around the center C.

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; An angular interval β between the conductive wires of a single turn of the coil around the rotation axis is set to be different from an angular interval α between the magnetic poles of the magnet around the rotation axis.

2. The coreless motor according to claim 1, wherein: The angular interval β is set to be larger than the angular interval α.

3. The coreless motor according to claim 2, wherein: The ratio β / α of the angular interval β to the angular interval α is set in a range of greater than 1.00 and less than or equal to 1.

25.

4. The coreless motor according to claim 2, wherein: The ratio β / α of the angular interval β to the angular interval α is set in a range of greater than 1.00 and not more than 1.

15.

5. The coreless motor according to claim 2, wherein: The ratio β / α of the angular interval β to the angular interval α is set in a range of greater than 1.00 and not more than 1.

10.

6. The coreless motor according to claim 2, wherein: The ratio β / α of the angular interval β to the angular interval α is set in a range of 1.05 to 1.

10.

7. The coreless motor according to claim 1, wherein: The single turn of the coil has a parallel portion extending parallel to the axial direction of the rotating shaft, and two oblique side portions extending in a direction inclined at an angle with respect to a plane perpendicular to the axial direction and connected to both ends of the parallel portion; 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 of the rotation axis is set in a range of 0.25 to 0.

40.

8. The coreless motor according to claim 1, wherein: The angular interval β is set to be smaller than the angular interval α.

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