Coreless electrical machine and coil arrangement

Abstract

Two-phase coreless electric machine (100), comprising: a rotor (300) containing a permanent magnet (320) and rotating about a central axis (C); and a stator (200) which contains a coil arrangement (210AS, 230AS) with a combination of several magnet coils (210) and is aligned concentrically to the rotor (300) via a gap of the rotor (300), wherein each of the magnetic coils (210) is designed as a concentrated winding coil comprising an upper base part (211) parallel to the central axis (C), a lower base part (212) opposite the upper base part (211), two leg parts (213 and 214) connecting the upper base part (211) and the lower base part (212), and an air core region (218) surrounded by the upper base part (211), the lower base part (212) and the two leg parts (213 and 214), each of the magnetic coils (210) has a trapezoidal shape in a top view, both the upper base part (211), the lower base part (212) and the two leg parts (213 and 214) have a linear shape, the two leg parts (213 and 214) are formed to set an angle of less than 90 degrees between the lower base part (212) and each of the leg parts (213 and 214), the upper base part (211) and the lower base part (212) are each aligned on two circumferential lines at different distances from the central axis (C) and each of the two leg parts (213 and 214) has a height difference section to connect the upper base part (211) and the lower base part (212), and the coil arrangement (210AS, 230AS) has a structure in which (i) the coil arrangement (210AS, 230AS) is formed by aligning the magnetic coils (210) at regular intervals in a circular direction around the central axis (C); (ii) the magnetic coils (210) are connected in such a way that any two of the magnetic coils (210) that are adjacent to each other in the circular direction belong to different phases; (iii) the upper base part (211) of each magnetic coil (210) is housed in the air core region (218) of another of the magnetic coils (210) that is adjacent to each magnetic coil (210) on one side of the upper base part (211);and (iv) the upper base part (211) and the two leg parts (213 and 214) of each magnet coil (210) are directed in a circular direction corresponding to those of the upper base part (211) and the two leg parts (213 and 214) of another of the magnet coils (210) which is adjacent to each magnet coil (210) on one side of the lower base part (212), without superimposing the corresponding parts of the upper base part (211) and the two leg parts (213 and 214) of the other magnet coil (210) in a radial direction of the stator (200), wherein ; the upper base part (211) is located at a greater distance from the central axis (C) of the rotor (300) than the lower base part (212).

Description

Background area

[0001] The present application relates to a coreless electrical machine, such as an electric motor or a generator. State of the art

[0002] JP 2010-141975A discloses a motor that uses a group of lumped winding coils with air cores. Each of the motor's coils partially overlaps an adjacent coil, and these coils are oriented such that they are equidistant from a permanent magnet. In this motor, the equal distance of the coils to the permanent magnet reduces torque ripple induced in the motor.

[0003] However, according to previous background technology, efforts were insufficient for a specific coil shape, making it difficult to create a coreless electrical machine with low torque ripple.

[0004] EP 2 642 636 A1 discloses the following: This document relates to a hollow cylindrical ironless winding for an electric motor. The winding comprises a plurality of individual coils distributed around the circumference of the winding, each individual coil comprising a plurality of turns wound helically around a winding axis perpendicular to an axis of the winding. Successive individual coils overlap in a tile-like fashion. According to the invention, the winding comprises at least two phase windings, each phase winding consisting of several of the individual coils. The phase windings are offset from one another in the circumferential direction of the hollow cylindrical winding, such that the individual coils of a first phase winding are arranged between the individual coils of a second phase winding in the circumferential direction of the hollow cylindrical winding.Each of the phase windings is wound from a continuous wire.

[0005] US 7,671,504 B2 discloses the following: An electric motor with an air-core winding is disclosed, the winding being composed of a plurality of individual coils of wire, wherein the individual coils overlap in a scale-like manner and the individual coils are pre-formed to an offset at least in the region of two opposite corners, such that half of the legs lie in a first plane and half of the legs lie in a second plane. This allows for a more cost-effective and robust construction of air-core windings for electric motors.

[0006] US 6,140,734 A discloses the following: Regular windings for use in the armature of an electric motor. Windings, each having approximately the same shape as a regular winding, can be overlapped to increase the conductor density in a volume that includes portions of the windings by having a portion of each winding at least partially fill an opening of an adjacent overlapping winding. The windings are assigned to the phases used to operate an electric motor. The windings and armature are especially useful for electric linear motors and stepper motors used in semiconductor manufacturing. Windings of the same shape improve the manufacturability of the armature and the electric motor. High conductor densities in the windings significantly improve the efficiency of the electric motor.

[0007] Further state of the art is disclosed in JP 2003 - 70 197 A, JP H05 - 15 648 U and WO 2011 / 139 396 A1. Summary

[0008] The invention is defined by the attached claims.

[0009] The present invention was created to solve at least one of the preceding problems and is feasible according to the following aspects. (1) A first aspect of the present invention is a two-phase coreless electric machine comprising: a rotor containing a permanent magnet and rotating about a central axis; and a stator comprising a coil arrangement with an assembly of several magnet coils and aligned concentrically to the rotor via a gap in the rotor. Each of the magnet coils is designed as a concentrated winding coil comprising an upper base part parallel to the central axis, a lower base part opposite the upper base part, two leg parts connecting the upper base part and the lower base part, and an air core region surrounded by the upper base part, the lower base part, and the two leg parts. The two leg parts are formed,to establish an angle of less than 90 degrees between the lower base and each of the leg sections. The upper and lower bases are each aligned on two circumferential lines at different distances from the central axis, and each of the two leg sections has a height-difference section to connect the upper and lower bases. The coil assembly has a structure in which (i) the coil assembly is formed by aligning the magnet coils at regular intervals in a circular direction around the central axis; (ii) the magnet coils are connected such that any two magnet coils adjacent to each other in the circular direction belong to different phases; (iii) the upper base of each magnet coil is located in the air core region of another magnet coil adjacent to each other on one side of the upper base.is housed; and (iv) the upper base part and the two leg parts of each magnet coil are oriented in a circular direction corresponding to those of the upper base part and the two leg parts of another of the magnet coils adjacent to each magnet coil on one side of the lower base part, without superimposing the corresponding upper base part and the two leg parts of the other magnet coil in a radial direction of the stator.

[0010] Following the coreless electric machine of the preceding first aspect, the magnet coil and the coil arrangement exhibit the preceding features (i) to (iv). This creates a two-phase coreless electric machine with low torque ripple using this coil arrangement.

[0011] (2) A second aspect of the present invention is a three-phase coreless electric machine comprising: a rotor containing a permanent magnet and rotating about a central axis; and a stator comprising a coil arrangement with an array of several magnet coils and aligned concentrically to the rotor via a gap in the rotor. Each of the magnet coils is designed as a concentrated winding coil comprising an upper base part parallel to the central axis, a lower base part opposite the upper base part, two leg parts connecting the upper base part and the lower base part, and an air core region surrounded by the upper base part, the lower base part, and the two leg parts. The two leg parts are formed,to establish an angle of less than 90 degrees between the lower base and each of the leg sections. The upper and lower bases are each aligned on two circumferential lines at different distances from the central axis, and each of the two leg sections has a height-difference section to connect the upper and lower bases. The coil assembly has a structure in which (i) the coil assembly is formed by aligning the magnet coils at regular intervals in a circular direction around the central axis; (ii) the magnet coils are connected such that any three of the magnet coils adjacent to each other in the circular direction belong to different phases; (iii) the respective upper bases of each pair of magnet coils adjacent to each other in the circular direction are located in the air core region of another of the magnet coils,which is adjacent to the two magnet coils on one side of the upper base part; and (iv) the upper base part and the two leg parts of each magnet coil are oriented in a circular direction corresponding to those of the upper base part and the two leg parts of another of the magnet coils adjacent to each magnet coil on one side of the lower base part, without superimposing the corresponding upper base part and the two leg parts of the other magnet coil in a radial direction of the stator.

[0012] Following the coreless electric machine of the preceding second aspect, the magnet coil and the coil arrangement exhibit the preceding features (i) to (iv). This creates a three-phase coreless electric machine with low torque ripple using this coil arrangement.

[0013] (3) In the coreless electrical machine of all the preceding aspects, the two leg parts of each of the magnetic coils can touch the two leg parts of the other magnetic coils that are adjacent to each magnetic coil on the side of the lower base part in the circular direction.

[0014] This coreless electric machine allows for an increase in coil wire density.

[0015] (4) In the coreless electric machine of all the preceding aspects, each of the magnetic coils can have a trapezoidal shape in a top view.

[0016] This coreless electric machine allows the magnetic coils to be closely aligned to permit a further increase in coil wire density.

[0017] (5) In the coreless electrical machine of all the preceding aspects, each of the magnetic coils can have two coil ends and the two coil ends can be taken from a coil end part of the lower base part.

[0018] This coreless electric machine creates a training that facilitates the power supply of each magnetic coil.

[0019] (6) A third aspect of the present invention is a coil arrangement comprising several magnetic coils arranged in a ring-like pattern. Each magnetic coil has an upper base part parallel to a central axis of the ring-like shape, a lower base part opposite the upper base part, and two leg parts connecting the upper base part and the lower base part. The upper base part and the lower base part are each aligned on a first circumferential line and a second circumferential line in the coil arrangement. At opposite ends of the upper base part, the upper base part is connected to the leg parts at positions on the first circumferential line. At opposite ends of the lower base part, the lower base part is connected to the leg parts at positions on the second circumferential line.

[0020] This coil arrangement creates a coreless electric machine with low torque ripple.

[0021] (7) A fourth aspect of the present invention comprises a magnetic coil, a linear upper base part, a lower base part parallel to and opposite the upper base part and longer than the upper base part, two leg parts connecting the upper base part and the lower base part, and an air core region surrounded by the upper base part, the lower base part, and the two leg parts. The two leg parts are formed to establish an angle of less than 90 degrees between the lower base part and each of the leg parts. At opposite ends of the upper base part, the upper base part is connected to the leg parts at positions outside a plane containing the lower base part. At opposite ends of the lower base part, the lower base part is connected to the leg parts at positions inside the plane.

[0022] This magnetic coil creates a coreless electric machine with low torque ripple.

[0023] (8) A fifth aspect of the present invention is a two-phase coreless electric machine comprising: a slide containing a permanent magnet and moving along a predetermined axis of motion; and a stator comprising a coil arrangement with several magnet coils grouped together along the axis of motion. Each of the magnet coils is designed as a concentrated winding coil comprising an upper base part perpendicular to the axis of motion, a lower base part parallel to and opposite the upper base part and at the same distance from the axis of motion as the upper base part, two leg parts connecting the upper base part and the lower base part, and an air core region surrounded by the upper base part, the lower base part, and the two leg parts. Each of the two leg parts has a height difference section formed at a positionwhich is connected to the upper base part or the lower base part. The coil arrangement has a structure in which (i) the coil arrangement is formed by aligning the magnetic coils at regular intervals in one direction of the axis of motion; (ii) the magnetic coils are connected such that any two of the magnetic coils adjacent to each other in the direction of the axis of motion belong to different phases; (iii) the upper base part of each of the magnetic coils is housed in the air core region of another of the magnetic coils adjacent to each magnetic coil on one side of the upper base part; and (iv) the upper base part and the two leg parts of each of the magnetic coils are oriented in the direction of the axis of motion corresponding to those of the upper base part and the two leg parts of the other of the magnetic coils adjacent to each magnetic coil on one side of the lower base part.without superimposing the corresponding parts of the upper base and the two leg parts of the other magnetic coil in a direction perpendicular to the axis of movement.

[0024] Following the coreless electric machine of the preceding fifth aspect, the magnet coil and the coil arrangement exhibit the preceding features (i) to (iv). This creates a two-phase coreless electric machine with low torque ripple using this coil arrangement.

[0025] (9) A sixth aspect of the present invention is a three-phase coreless electric machine comprising: a slide containing a permanent magnet and moving along a predetermined axis of motion; and a stator comprising a coil arrangement with several magnet coils grouped together along the axis of motion. Each of the magnet coils is designed as a concentrated winding coil comprising an upper base part perpendicular to the axis of motion, a lower base part parallel to and opposite the upper base part and located at the same distance from the axis of motion as the upper base part, two leg parts connecting the upper base part and the lower base part, and an air core region surrounded by the upper base part, the lower base part, and the two leg parts. Each of the two leg parts has a height difference section formed at a positionwhich is connected to the upper base part or the lower base part. The coil arrangement has a structure in which (i) the coil arrangement is formed by aligning the magnetic coils at regular intervals in one direction of the axis of motion; (ii) the magnetic coils are connected such that three of the magnetic coils adjacent to each other in the direction of the axis of motion belong to different phases; (iii) the upper base part of each of the magnetic coils is housed in the air core region of another of the magnetic coils that is adjacent to each magnetic coil on one side of the upper base part; and (iv) the upper base part and the two leg parts of each of the magnetic coils are oriented in the direction of the axis of motion corresponding to those of the upper base part and the two leg parts of yet another of the magnetic coils that is adjacent to each magnetic coil on one side of the lower base part.without superimposing the corresponding parts of the upper base and the two leg parts of the other magnetic coil in a direction perpendicular to the axis of movement.

[0026] Following the coreless electric machine of the preceding sixth aspect, the magnet coil and the coil arrangement exhibit the preceding features (i) to (iv). This creates a three-phase coreless electric machine with low torque ripple using this coil arrangement. Brief description of the drawings Fig. Figure 1 is a cross-section of a coreless motor according to a first embodiment; Fig. 2A is a perspective view of a magnetic coil according to the first embodiment; Fig. 2B is a front view of the magnetic coil according to the first embodiment; Fig. 2C is a top view of the magnetic coil according to the first embodiment; Fig. Figure 3 is a perspective view of a coil arrangement according to the first embodiment; Fig. Figure 4A is an explanatory diagram showing how several magnetic coils are stacked on top of each other; Fig. 4B is an explanatory diagram showing how the multiple magnetic coils are stacked on top of each other; Fig. 4C is an explanatory diagram showing how the multiple magnetic coils are stacked on top of each other; Fig. Figure 5 is an explanatory illustration showing a connection state of the magnetic coils according to the first embodiment; Fig. Figure 6A is an explanatory illustration showing one step in the formation of the magnetic coil; Fig. Figure 6B is an explanatory illustration showing one step in the formation of the magnetic coil; Fig. Figure 7 is an explanatory illustration showing structural examples of coil lead wires; Fig. 8A is a perspective view of a magnetic coil based on an example; Fig. 8B is a front view of the magnetic coil according to the example; Fig. 8C is a top view of the magnetic coil according to the example; Fig. Figure 9 is a perspective view of a coil arrangement according to the example; Fig. 10A is a perspective view of a magnetic coil according to a second embodiment; Fig. 10B is a front view of the magnetic coil according to the second embodiment; Fig. 10C is a top view of the magnetic coil according to the second embodiment; Fig. Figure 11 is a perspective view of a coil arrangement according to the second embodiment; Fig. Figure 12 is an explanatory illustration showing several magnetic coils in a state where they are stacked on top of each other; Fig. Figure 13 is an explanatory illustration showing a connection state of the magnetic coils according to the second embodiment; and Fig. Figure 14 is a cross-section showing a coreless motor with an external rotor structure. Detailed Description A. First Design

[0027] Fig. Figure 1 is a cross-section of a coreless motor 100 as a coreless electric machine according to a first embodiment. The coreless motor 100 is an inside-rotor type motor having a radial gap structure comprising a housing 110, a stator 200, and a rotor 300. Fig. Figure 1 shows an X direction, a Y direction, and a Z direction orthogonal to each other. The Y direction is a direction parallel to a central axis C of the rotor 300. If necessary, the X, Y, and Z directions are shown in Fig. 1 also in Fig. 2 and the following drawings.

[0028] The rotor 300 includes a rotor shaft 310 that rotates about the central axis C and a permanent magnet 320 located outside the rotor shaft 310. While it is possible that only one permanent magnet 320 may be provided, two or more permanent magnets 320 are usually provided. Each permanent magnet 320 is magnetized in a radial direction according to an outward direction from the central axis C of the rotor 300. The direction of magnetization of the permanent magnet 320 is not limited to the radial direction (or radiation direction from the center); the permanent magnet 320 can also be magnetized in another direction, such as parallel magnetization. The "radial direction of the rotor 300" means a direction perpendicular to the central axis C of the rotor 300, extending outward from the central axis C in a radial pattern.The opposite end regions of the rotor shaft 310 are supported by carriers 120, which are provided on the housing 110.

[0029] The stator 200 is housed in the casing 110 and is radially aligned across a gap outside the rotor 300. The stator 200 includes a coil back yoke 250, which is provided in the casing 110, and several magnetic coils 210, which are located inside the coil back yoke 250. The coil back yoke 250 is made of a magnetic material and has an almost cylindrical shape. The coils 210 are formed with resin 170, which exhibits excellent thermal conductivity, insulating properties, and rigidity. The coil leads of the magnetic coils 210 are each connected to a connecting substrate 150. A coil terminal 160 for power supply is taken from the connecting substrate 150 to the outside of the casing 110.

[0030] The magnetic coils 210 each contain an effective coil section VCP, and a first coil end section CE1 and a second coil end section CE2, which are provided on opposite sides of the effective coil section VCP. The effective coil section VCP is a coil section used to efficiently convert energy between electrical and mechanical energy. The coil end sections CE1 and CE2 are coil sections that are not directly involved in the energy conversion. In the presence of the coil back yoke 250, a coil section that overlaps the coil back yoke 250 in the radial direction corresponds to the effective coil section VCP, and a coil section that does not overlap the coil back yoke 250 in the radial direction corresponds to the coil end sections CE1 and CE2. The shape of the magnetic coil 210 will be described in more detail later.

[0031] The housing 110 contains a magnetic sensor 140 as a position sensor for determining the rotational position of the rotor 300. The magnetic sensor 140 is connected to a switching plate 130. In this embodiment, the magnetic sensor 140 and the switching plate 130 are aligned on opposite sides of the permanent magnet 320 and on the same side as the second coil end part CE2.

[0032] Fig. 2A, Fig. 2B and Fig. Figures 2C are each a perspective view, a front view and a side view of the magnetic coil 210. Fig. Figure 3 is a perspective view of a coil arrangement 210AS with the magnetic coils 210, which are in Fig. 2A to 2C were shown and are combined in a cylindrical or ring shape. In Fig. Figure 3 shows that the symbols “(A)” and “(B)” inserted after the reference numeral 210 of the magnetic coils indicate a difference between an A phase and a B phase. Accordingly, the coreless motor 100 of the first embodiment is designed as a two-phase motor.

[0033] From above in Fig. 2C the magnetic coil 210 is designed as a concentrated winding coil which has a trapezoidal shape with an upper base part 211 parallel to the central axis C of the rotor 300 ( Fig. 1) has a lower base part 212, which is opposite the upper base part 211, and two leg parts 213 and 214, which connect the upper base part 211 and the lower base part 212. The upper base part 211, the lower base part 212, and the two leg parts 213 and 214 all have a linear shape. The upper base part 211 is shorter than the lower base part 212. As in Fig. Figure 2C shows the upper base part 211 and the lower base part 212 as two parallel coil parts, both extending in one direction (Y direction) parallel to the central axis C of the rotor 300 and both comprising a section corresponding to the effective coil part VCP in Fig. 1. A space enclosed by the upper base part 211, the lower base part 212, and the two leg parts 213 and 214 is referred to as the "air core area 218". The two leg parts 213 and 214 are shaped such that they establish an angle θ1 between the lower base part 212 and the leg part 213, and an angle θ2 between the lower base part 212 and the leg part 214, at less than 90 degrees. In this example, the two angles θ1 and θ2 are set at the same degree, and the magnet coil 210 has an isosceles trapezoidal shape in a top view. However, the angles θ1 and θ2 can also be set at different degrees. The “top view” means that a state of the magnetic coil 210 is observed when the magnetic coil 210 is placed on a plane and viewed in a direction perpendicular to that plane.While the magnetic coil 210 is observed in a top view, the upper base part 211 and the lower base part 212 are parallel to each other, and the leg parts 213 and 214 extend from the upper base part 211 and the lower base part 212 in obliquely inclined directions. In this description, the "trapezoidal shape" does not only include a trapezoid in the strict sense, but a shape in which a connection between an upper base or a lower base and a leg part is bent at a curve or is bent as such, like the one in [reference]. Fig. Figure 2C shows a trapezoidal shape. Forming the magnetic coil 210 into a trapezoidal shape in the top view allows the magnetic coil 210 to be tightly aligned and enables an increase in coil wire density.

[0034] As from Fig. As can be seen in Figure 3, the upper base part 211 and the lower base part 212 of the magnet coil 210 are aligned on two circumferential lines at different distances from the central axis C of the rotor 300. More precisely, the upper base part 211 is located at a greater distance from the central axis C of the rotor 300 than the lower base part 212. As shown in Figure 3, the upper base part 211 and the lower base part 212 of the magnet coil 210 are aligned on two circumferential lines at different distances from the central axis C of the rotor 300. More precisely, the upper base part 211 is located at a greater distance from the central axis C of the rotor 300 than the lower base part 212. Fig. 2A and Fig. As shown in Figure 2B, the two leg sections 213 and 214 each have a height difference section for connecting the upper base section 211 and the lower base section 212. More precisely, the leg sections 213 and 214 each have a Z-shaped profile to connect the upper base section 211 and the lower base section 212. At opposite ends of the upper base section 211, the upper base section 211 is connected to the leg sections 213 and 214 at positions on the first perimeter line on which the upper base section 211 is located. At opposite ends of the lower base section 212, the lower base section 212 is connected to the leg sections 213 and 214 at positions on the second perimeter line on which the lower base section 212 is located. The first circumferential line is aligned outside the second circumferential line (a position at a greater distance from the central axis of the coil arrangement).The height difference sections of leg parts 213 and 214 are connections between the first circumferential line and the second circumferential line at positions closer to the lower base part 212 than to the upper base part 211. As in . Fig. As shown in Figure 2C, the first leg section 213 has an outer side surface 213o and an inner side surface 213i. In a top view, the width of the leg section 213 is constant, and the outer side surface 213o and the inner side surface 213i of the leg section 213 are parallel to each other. Accordingly, the second leg section 214 has an outer side surface 214o and an inner side surface 214i. The width of the leg section 214 is constant, and the outer side surface 214o and the inner side surface 214i are parallel to each other. The magnet coil 210 has two coil ends 215 and 216, which consist of the lower base section 212, the second coil end section CE2 ( Fig. 1) listened to, extracted. This enables the formation of a training that facilitates the power supply of each magnetic coil 210.

[0035] As in Fig. As shown in Figure 3, the coil arrangement 210AS can be formed by positioning the coils 210 in a ring-like pattern at regular intervals in a circular direction around the central axis C of the rotor 300 and by connecting the coils 210 to each other. At this point, a coil wire density can be increased by positioning the coils 210 such that the respective first leg sections 213 of adjacent coils 210 touch each other in the circular direction and the respective second leg sections 214 of adjacent coils 210 touch each other in the circular direction. In this case, the coil 210 preferably has an isosceles trapezoidal shape in a top view. This creates an alignment of the coils 210 in which all coils 210 are neatly oriented in the circular direction around the central axis C of the rotor 300.This allows for a sufficient increase in coil wire density without causing an increase in the size of the coreless motor 100 in any axial direction. In the first embodiment, the magnetic coils 210 are connected in such a way that any two magnetic coils 210 that are adjacent to each other in the circular direction belong to different phases (A phase or B phase).

[0036] As from Fig. As can be seen from Figure 3, the magnetic coils 210 are aligned, with the respective leg sections 213 and 214 touching each other with virtually no gap. This allows for a sufficient increase in the coil wire density of the coil arrangement 210AS. As described above, the upper base section 211 and the lower base section 212 of each of the magnetic coils 210 are aligned on two circumferential lines at different distances from the central axis C of the rotor 300. The application of these characteristic shapes and orientations ensures the maintenance of a constant distance from the permanent magnet 320. Fig. 1) to each magnetic coil 210. More precisely, the distance from the permanent magnet 320 to each magnetic coil of phase A 210(A) and magnetic coil of phase B 210(B) is always kept constant. This enables the realization of the coreless motor 100 with low torque ripple.

[0037] In this description, “torque ripple” means that both fluctuations are contained in a driving torque to occur when the coreless motor 100 is used as a motor, and fluctuations are contained in a braking torque to occur when the coreless motor 100 is used as a generator.

[0038] Fig. Figures 4A to 4C are explanatory illustrations showing how several magnetic coils 210 are stacked on top of each other. In each of these drawings, the upper part shows a front view of three magnetic coils 210a, 210b, and 210c, and the lower part shows a top view of the magnetic coils 210a, 210b, and 210c. The letters "a," "b," and "c" inserted after the reference numeral 210 of the magnetic coils serve only to distinguish three magnetic coils 210 from one another, while these magnetic coils 210 have nearly the same shape. In the order of Fig. 4A, Fig. 4B and Fig. 4C the distances between the magnetic coils 210a, 210b and 210c are gradually reduced and Fig. 4C shows the same ratio in terms of their positions as those of the in Fig. 3 shown coil arrangement 210AS. In the lower part of Fig. In the top view shown in 4C, the magnetic coils 210a, 210b and 210c are provided with reference numerals, so that they each have the upper base parts 211a, 211b and 211c, the lower base parts 212a, 212b and 212c, the first leg parts 213a, 213b and 213c and the second leg parts 214a, 214b and 214c.

[0039] As from Fig. As can be seen from 4C, the coil arrangement 210AS has the following features (characters “a”, “b” and “c” are omitted). (1) The upper base part 211 of each of the magnetic coils 210 is located in the air core area 218 ( Fig. 2C) another of the magnetic coils 210, which is adjacent to each magnetic coil 210 on the side of the upper base part 211. (2) The upper base part 211 and the two leg parts 213 and 214 of each of the magnet coils 210 are each arranged in a circular direction around the central axis C of the rotor 300 ( Fig. 1) aligned with those of another of the magnetic coils 210, which is adjacent to each magnetic coil 210 on the side of the lower base part 212, without superimposing those of the other magnetic coil 210 in the radial direction.

[0040] Fig. Figure 5 is an explanatory illustration showing a connection state of the magnetic coils 210 according to the first embodiment. The uppermost part of Fig. Figure 5 shows a section of the magnetic coil of Phase A 210(A), and a section of the magnetic coil of Phase B 210(B) is shown below the magnetic coil of Phase A 210(A). Rectangles labeled "A+", "A-", "B+", and "B-" of magnetic coils 210(A) and 210(B) indicate sections of the effective coil section VCP in Fig. 1 (namely the upper base part 211 or the lower base part 212 in Fig. 2A) and the symbols "A+", "A-", "B+" and "B-" indicate differences in current direction. The lower part of Fig. Figure 5 shows the position of the coil assembly 210AS, which contains the A phase and the B phase, as well as the positions of the multiple permanent magnets 320 relative to each other. For the sake of simplicity, the coil assembly 210AS and the permanent magnet 320 are depicted along straight lines. As can be seen from this drawing, the magnet coil of phase A 210(A) and the magnet coil of phase B 210(B) are aligned at the same distance G from the permanent magnet 320. This makes it possible to easily implement the two-phase coreless motor 100 with low torque ripple.

[0041] Fig. 6A and Fig. Figure 6B contains explanatory diagrams showing the steps involved in forming the magnetic coil 210. First, the following is shown in Fig. In step 6A, a coil lead wire is provided and the coil lead wire is wound outside both of the opposite end sections from a near center position in an α-winding fashion to form two coil parts 210u and 210d from the single coil lead wire. Arrows in the drawing indicate a winding direction WD. The left part of Fig. 6A is a gamble and the right part of Fig. 6A is a cross-section of an effective coil section. The coil ends 215 and 216 each protrude outwards from the two coil sections 210u and 210d. Next, in which Fig. In step 6B, the two coil sections 210u and 210d are positioned opposite each other, one above the other, to form the planar magnetic coil 210. Arrows in the drawing indicate a current direction, which is determined when a current flows from the coil end 215. Next, the planar magnetic coil 210 is subjected to a bending operation, thereby bending the magnetic coil 210 with the Fig. The coil parts are acquired in the form shown in sections 2A to 2C. Although coil parts 210u and 210d are described as having the same number of stacked wire layers, the number of stacked wire layers does not need to be the same; it can differ between coil parts 210u and 210d. For example, coil part 210u may have a single-layer structure, and coil part 210d may have a four-layer structure.

[0042] Fig. Figure 7 is an explanatory illustration showing structural examples of coil leads used to form magnetic coils. One in the top row of Fig. Figure 7 shows a first coil lead wire 410 containing a wire bundle 412, which is a bundle of several uninsulated leads 411, all made of uninsulated wire, and an insulating coating 414 covering the circumference of the wire bundle 412. The insulating properties of the insulating coating 414 only need to withstand an induced voltage generated in one turn of the coil lead wire 410 of the magnet coil. A second insulating covering, which will be described later, serves to guarantee the insulating properties for withstanding potential differences that occur between the coils and between the phases. The uninsulated lead wire 411 is, for example, a bare copper wire. A self-welding layer 416 is formed around the insulating coating 414.The self-welding layer 416 is activated by heat or a solvent to perform the function of welding adjacent coil conductor wires 410 together. The self-welding layer 416 can be omitted. The conductor wire bundle 412 is not braided. Although the coil conductor wire 410 has a circular shape in one section, it can also be formed into a nearly rectangular shape in one section.

[0043] An enamelled wire, commonly used as a coil lead wire, is formed from conductor wires, each insulated by an insulating cover. This causes a problem, namely that a relatively large eddy current is generated in a magnet coil when the permanent magnet 320 passes near the magnet coil. The eddy current can be reduced, for example, by using a stranded wire (a wire with twisted enamelled wires). However, the present inventor has found that using the stranded wire as a coil lead wire causes a problem, namely the occurrence of local excessive expansion or breakage during the formation of the magnet coil. In contrast, the wire described in Fig. Figure 7 shows the coil lead wire 410, the lead wire bundle 412 as a bundle of uninsulated lead wires 411, and the insulating coating layer 414 covering the circumference of the lead wire bundle 412. This reduces the occurrence of local excessive expansion or breakage of the magnet coil. The experiment carried out by the present inventor shows that even if the diameter of the uninsulated lead wire 411 is smaller than the diameter of a copper wire in a commercially available stranded wire, the occurrence of breakage of the first coil lead wire 410 is still reduced compared to the stranded wire.

[0044] The present inventor has further investigated experimentally the magnitude of an eddy current generated in the first coil lead wire 410 and found that the diameter of the lead wire can be reduced compared to the case where a stranded wire is used, in order to allow a significant reduction of the eddy current. The eddy current is generated in a direction that prevents a change in the position of the permanent magnet and thus causes resistance to the rotation of a coreless motor. Therefore, the eddy current must be reduced. The eddy current was investigated by an experiment carried out by moving a permanent magnet so that the permanent magnet passed a position near a surface of the coil lead wire 410, which was placed in a linear pattern, and by measuring a force generated on the coil lead wire 410 during the movement.In this case, it is assumed that the force generated on the coil lead wire 410 is proportional to the magnitude of the eddy current generated on the coil lead wire 410.

[0045] Insulating properties for withstanding potential differences that occur between the coils and between the phases can be guaranteed by further completely covering each of the magnetic coils 210 with the second insulating cover, after the formation of each of the magnetic coils 210 with the in Fig. The form shown in 2A to 2C is achieved by using the first coil conductor wire 410. The second insulating cover preferably consists of insulating material that has superior dielectric strength characteristics than the insulating coating layer 414 around the conductor wire bundle 412.

[0046] An eddy current flows in a vortex pattern in one cross-sectional direction of the coil-forming uninsulated conductor wire 411, so a smaller cutting area of ​​the uninsulated conductor wire 411 is preferred. More precisely, a setting of the cutting area to 0.04 mm is preferred. 2 or less preferred. Ideally, the cutting range should be 0.02 mm. 2 or less adjusted. Meanwhile, consideration should be given to such training in relation to an increase in electrical resistance as a consequence of the reduction in the cutting area.

[0047] A second coil lead wire 420, located in the middle row of Fig. Figure 7 also includes a conductor wire bundle 422, which is a bundle of several uninsulated conductor wires 421, all made of uninsulated wire, and an insulating coating layer 424 covering the circumference of the conductor wire bundle 422. The uninsulated conductor wire 421 is, for example, a bare copper wire. A self-welding layer 426 is formed around the insulating coating layer 424. The conductor wire bundle 422 is braided, in this example, a flat braid. Although the coil conductor wire 420 has a nearly rectangular shape in one section, it can also be formed into a circular shape in one section. The coil conductor wire 420, which contains the braided conductor wire bundle 422, improves the elongation properties of the coil conductor wire 420.As a result, it is possible to further reduce the occurrence of local excessive expansion or breakage of a magnet coil when the magnet coil is formed by winding the coil lead wire 420. In particular, the flat braiding of the lead wire bundle 422 makes it possible to control the expansion properties in both of the two orthogonal directions (right-to-left direction and top-to-bottom direction). Fig. 7) to improve.

[0048] The magnitude of an eddy current generated on the second coil lead wire 420 was significantly reduced compared to the case of the first coil lead wire 410. One possible reason is that braiding the lead wire bundle 422 allows a significant reduction in the diameter of the uninsulated lead wire 421, compared to the diameter of a copper wire in a stranded wire, and further fragments the path of an eddy current, making the occurrence of an eddy current unlikely.

[0049] In this training, where the uninsulated conductor wires 421 are braided, setting the cutting area of ​​each uninsulated conductor wire 421 to 0.04 mm causes 2 or less or 0.02 mm 2 or less no problems as a result of the increased electrical resistance. One possible reason for this is that although the electromotive force of an eddy current is small and the eddy current therefore cannot flow through the uninsulated conductor wires 421 and weakens, a coil current is supplied by applying a sufficient voltage to flow through uninsulated conductor wires.

[0050] A third coil lead wire 430, located in the lower row of Fig. Figure 7 also includes a conductor wire bundle 432, which is a bundle of several uninsulated conductor wires 431, all made of uninsulated wire, and an insulating coating layer 434 covering the circumference of the conductor wire bundle 432. The uninsulated conductor wire 431 is, for example, a bare copper wire. A self-welding layer 436 is formed around the insulating coating layer 434. A plated layer 438 (for example, a tin-plated layer) is formed on one surface of each uninsulated conductor wire 431. The conductor wire bundle 432 is braided, in this example, a flat braid. Although the coil conductor wire 430 has a nearly rectangular shape in one section, it can also be formed into a circular shape in one section.The coil lead wire 430, which also contains the braided lead wire bundle 432, improves the elongation properties of the coil lead wire 430. As a result, it is possible to further reduce the occurrence of local excessive elongation or breakage of a magnet coil when the magnet coil is formed by winding the coil lead wire 430.

[0051] The magnitude of an eddy current generated on the third coil lead wire 430 was somewhat greater than the magnitude in the case of the second coil lead wire 420 and was almost the same as the magnitude in the case of the first coil lead wire 410. Therefore, with a view to reducing an eddy current, the use of an unclad copper wire as an uninsulated lead wire like the second lead wire 420 is preferred.

[0052] As described above, in the first embodiment, the upper base part 211 and the two leg parts 213 and 214 of each of the magnetic coils 210 are aligned in the circular direction with those of another magnetic coil 210 adjacent to the lower base part 212 of each magnetic coil 210, without superimposing those of the other magnetic coil 210 in the radial direction. This creates a two-phase coreless electric machine with low torque ripple. Example B.

[0053] Fig. 8A, Fig. 8B and Fig. Figure 8C shows a magnetic coil 220 according to an example and each corresponds to Fig. 2A to 2C, which refer to the first embodiment. Fig. Figure 9 is a perspective view of a 220AS coil arrangement with the components shown in Fig. The magnetic coils 220 shown in 8A to 8C are combined in a cylindrical or ring shape. The cross-section of the Fig. The design of the coreless motor shown in section 1, referring to the first embodiment, also applies to the example. The design of the second embodiment is the same as that of the first embodiment, except that one of the magnetic coils has a different shape.

[0054] As seen in the top view in Fig. As shown in Figure 8C, the magnetic coil 220 of the second embodiment is designed, like the magnetic coil 210 of the first embodiment, as a concentrated winding coil having a trapezoidal shape with an upper base part 221 parallel to the central axis C of the rotor 300 ( Fig. 1) has a lower base part 222, which is opposite the upper base part 221, and two leg parts 223 and 224, which connect the upper base part 221 and the lower base part 222. A space surrounded by the upper base part 221, the lower base part 222 and the two leg parts 223 and 224 is an air core region 228.

[0055] In the magnet coil 220 of the second embodiment, the distance between the central axis C of the rotor 300 and the upper base part 221, and the distance between the central axis C and the lower base part 222, are related to each other in the opposite way to the magnet coil 210 of the first embodiment. More precisely, in the magnet coil 220 of the second embodiment, the upper base part 221 is closer to the central axis C of the rotor 300 than the lower base part 222. At opposite ends of the upper base part 221, the upper base part 221 is connected to the leg parts 223 and 224 at positions on a first circumferential line on which the upper base part 221 is located. At opposite ends of the lower base part 222, the lower base part 222 is connected to the leg parts 223 and 224 at positions on a second circumferential line on which the lower base part 222 is located.The second circumferential line is aligned outside the first circumferential line (a position at a greater distance from the central axis of the coil arrangement). The height difference sections of the leg parts 223 and 224 are connections between the first circumferential line and the second circumferential line at positions closer to the lower base part 222 than to the upper base part 221. The other features of the shape are nearly identical to those of the first embodiment and are therefore not described here. This example also produces effects comparable to those of the first embodiment. C. Second embodiment

[0056] Fig. 10A, Fig. 10B and Fig. Figures 10C show a magnetic coil 230 according to a third embodiment and correspond to each other. Fig. 2A to 2C, which refer to the first embodiment. Fig. Figure 11 is a perspective view of a coil arrangement 230AS with the components shown in Fig. The magnetic coils shown in sections 10A to 10C are 230 ohms and are combined in a cylindrical or ring shape. Fig. Figure 11 shows the differences between a U phase, a V phase, and a W phase, indicated by the symbols “(U)”, “(V)”, and “(W)” inserted after the reference numerals 230 of the magnetic coils. Accordingly, a coreless motor of the third embodiment is designed as a three-phase motor.

[0057] The cross-sectional structure of the in Fig. The coreless motor 100 shown in Figure 1, which refers to the first embodiment, is essentially applicable to the second embodiment. The design of the third embodiment is almost identical to that of the first embodiment with two exceptions: One magnetic coil has a different shape; and the coreless motor is designed as a three-phase motor.

[0058] As seen in the top view of Fig. As shown in Figure 10C, the magnetic coil 230 of the third embodiment is designed, like the magnetic coil 210 of the first embodiment, as a concentrated winding coil having a trapezoidal shape with an upper base part 231 parallel to the central axis C of the rotor 300 ( Fig. 1) has a lower base part 232, which is opposite the upper base part 231, and two leg parts 233 and 234, which connect the upper base part 231 and the lower base part 232. The upper base part 231, the lower base part 232, and the two leg parts 233 and 234 all have a linear shape. The upper base part 231 is shorter than the lower base part 232. The upper base part 231 and the lower base part 232 are two parallel coil parts, both extending in one direction (Y direction) parallel to the central axis C of the rotor 300, and both having a section corresponding to the effective coil part VCP in Fig. 1. A space enclosed by the upper base part 231, the lower base part 232, and the two leg parts 233 and 234 is an air core region 238. The two leg parts 233 and 234 are formed such that they establish an angle θ1 between the lower base part 232 and the leg part 233, and an angle θ2 between the lower base part 232 and the leg part 234, to be less than 90 degrees. In this example, the two angles θ1 and θ2 are set to the same degree, and the magnet coil 230 has an isosceles trapezoidal shape in a top view. However, the angles θ1 and θ2 can also be set to different degrees.

[0059] The upper base part 231 and the lower base part 232 are aligned on two circumferential lines at different distances from the central axis C of the rotor 300. More precisely, the upper base part 231 is located at a greater distance from the central axis C of the rotor 300 than the lower base part 232. This positional ratio is the same as in the first embodiment. However, as in the second embodiment, the magnet coil 230 can be configured such that the upper base part 231 is closer to the central axis C of the rotor 300 than the lower base part 232. As in Fig. 10A and Fig. As shown in Figure 10B, the two leg sections 233 and 234 each have a height difference section for connecting the upper base section 231 and the lower base section 233. The magnetic coil 230 has two coil ends 235 and 236, which consist of the lower base section 232, the second coil end section CE2 ( Fig. 1) is heard, taken from. At opposite ends of the upper base part 231, the upper base part 231 is connected to the leg parts 233 and 234 at positions on a first circumferential line on which the upper base part 231 is located. At opposite ends of the lower base part 232, the lower base part 232 is connected to the leg parts 233 and 234 at positions on a second circumferential line on which the lower base part 232 is located. The second circumferential line is oriented outside the first circumferential line (a position at a greater distance from the central axis of the coil assembly). The height difference sections of the leg parts 233 and 234 are connections between the first circumferential line and the second circumferential line at positions that are closer to the lower base part 232 than to the upper base part 231.

[0060] As in Fig. As shown in Figure 11, a coil arrangement 230AS can be formed by positioning the coils 230 in a ring-like pattern at regular intervals in a circular direction around the central axis C of the rotor 300 and by connecting the coils 230 to each other. At this point, the coil wire density can be increased by positioning the coils 230 such that the respective first leg sections 233 of the adjacent coils 230 touch each other in the circular direction and the respective second leg sections 234 of the adjacent coils 230 also touch each other in the circular direction. In this case, the coil 230 preferably has an isosceles trapezoidal shape in a top view.In the third embodiment, the magnetic coils 230 are connected in such a way that three of the magnetic coils 230, which are adjacent to each other in the circular direction, belong to different phases (U phase, V phase or W phase), in contrast to the first embodiment and the second embodiment.

[0061] Fig. Figure 12 is an explanatory illustration showing the magnetic coils 230 in a state where they are stacked on top of each other in a top view and the view in the lower part of Fig. 4C correspond. The letters "a", "b", and "c" inserted after the reference numeral 230 of the magnetic coils serve only to distinguish three magnetic coils 230 from one another and show magnetic coils 230 with almost the same shape. The in Fig. The superimposed state shown in 12 is almost the same as the superimposed state of the in Fig. 11 shown coil arrangement 230AS. In Fig. 12 are a magnetic coil 230a, a magnetic coil 230b and a magnetic coil 230c, each designated with reference numerals 231a, 231b and 231c for their upper base parts, each designated with reference numerals 232a, 232b and 232c for their lower base parts, 233a, 233b and 233c for their first leg parts and 234a, 234b and 234c for their second leg parts.

[0062] As from Fig. As can be seen from Figure 12, the coil arrangement 230AS of the third embodiment has the following features (characters “a”, “b” and “c” are omitted). (1) The respective upper base parts 231 of each of the two magnetic coils 230, which are adjacent to each other in the circular direction, are housed in the air core area 238 of another of the magnetic coils 230, which is adjacent to the two magnetic coils 230 on the side of the upper base part 231. (2) The upper base part 231 and the two leg parts 223 and 234 of each of the magnet coils 230 are arranged in a circular direction around the central axis C of the rotor 300 ( Fig. 1) aligned with those of another of the magnetic coils 230, which is adjacent to each magnetic coil 230 on the side of the lower base part 232, without superimposing those of the other magnetic coil 230 in the radial direction.

[0063] Fig. Figure 13 is an explanatory illustration showing a connection state of the magnetic coils 230 according to the third embodiment. The upper part of Fig. Figure 13 shows a section of a solenoid coil of phase U 230(U), a section of a solenoid coil of phase V 230(V), and a section of a solenoid coil of phase W 230(W). Rectangles with the symbols “U+”, “U-”, “V+”, “V-”, “W+”, and “W-” of solenoid coils 230(U), 230(V), and 230(W) show sections of the effective coil part VCP (namely, the upper base part 231 or the lower base part 232), and the symbols “U+”, “U-”, “V+”, “V-”, “W+”, and “W-” indicate differences in current direction. The lower part of Fig. Figure 13 shows the position of the coil assembly 230AS, which contains the U phase, the V phase, and the W phase, as well as the positions of the multiple permanent magnets 320 relative to each other. For the sake of simplicity, the coil assembly 230AS and the permanent magnet 320 are depicted along straight lines. As can be seen from this drawing, the U phase magnet coil 230(U), the V phase magnet coil 230(V), and the W phase magnet coil 230(W) are aligned at the same distance G from the permanent magnet 320. This makes it possible to easily implement a three-phase coreless electric machine with low torque ripple.

[0064] The electric machine described in each of the preceding embodiments has an inner rotor structure with a rotor that is aligned within a coil arrangement. Meanwhile, the present invention is further applicable to an electric machine that has an outer rotor structure with a rotor that is aligned outside a coil arrangement.

[0065] Fig. Figure 14 is a cross-section showing a coreless motor 100a as an example of an electric machine having an external rotor structure. Parts similar to those of the coreless motor 100, which has a Fig. The internal rotor structure shown in Figure 1 corresponds to the corresponding components, which are designated with the same reference numerals and are not described in detail. In the section on Fig. In the coreless motor 100a shown in Figure 14, the permanent magnet 320 of the rotor 300 is externally aligned with the stator 200, with the magnetic coils 210 oriented radially in the presence of a gap between the permanent magnet 320 and the stator 200. The magnetic sensor 140 on the switching plate 130 is positioned opposite the permanent magnet 320. A connector 180 for connecting to an external wire is attached to the switching plate 130. As in the inner rotor structure, in the outer rotor structure, the stator 200 is aligned concentrically with the rotor 300, with a gap between the rotor 300 and the motor. The electric machine with this outer rotor structure produces effects almost comparable to those produced by the electric machine with the inner rotor structure.

[0066] As can be seen from the conceptual representations in Fig. 5 and Fig.As can be seen from Figure 13, the present invention is not limited to a rotating electric machine, but is also applicable to a linear electric machine. This applicability can be achieved, for example, by changing the "rotor rotating about the central axis" described in the preceding embodiments to a "slider moving along the axis of motion." The design of this electric machine is such that an upper base part and a lower base part of a magnetic coil are located parallel to each other on two planes, and a coil arrangement contains several magnetic coils that move at regular intervals in the direction in which the slider moves. Reference symbol list 100 coreless motor 110 cases 120 carriers 130 switching plate 140 magnetic sensor 150 compound substrate 160 coil connection 170 Harz 200 Stator 210 Magnetic coil 210AS coil arrangement 211 upper base part 212 lower base part 213, 214 thigh section 213i inner side surface 213° outer side surface 214i inner side surface 214° outer side surface 215, 216 Coil end 218 Air core area 220 magnetic coil 220AS coil arrangement 221 upper base part 222 lower base part 223, 224 thigh section 225, 226 Coil end 228 Air core area 230 magnetic coil 230AS coil arrangement 231 upper base part 232 lower base part 233, 234 thigh section 235, 236 Coil end 238 Air core area 250 coil return yoke 300 Rotor 310 Rotor shaft 320 permanent magnet 410 coil lead wire 411 non-insulated conductor wire 412 conductor wire bundles 414 insulating coating layer 420 coil lead wire 421 non-insulated conductor wire 422 conductor wire bundles 424 insulating coating layer 426 self-welding layer 430 coil lead wire 431 non-insulated conductor wire 432 conductor wire bundles 434 insulating coating layer 436 self-welding layer 438 plated layer

Claims

[1] Two-phase coreless electric machine (100), comprising: a rotor (300) containing a permanent magnet (320) and rotating about a central axis (C); and a stator (200) containing a coil arrangement (210AS, 230AS) with a combination of several magnetic coils (210) and aligned concentrically with the rotor (300) across a gap of the rotor (300), wherein each of the magnetic coils (210) is formed as a concentrated winding coil having an upper base part (211) parallel to the central axis (C), a lower base part (212) opposite the upper base part (211), two leg parts (213 and 214) connecting the upper base part (211) and the lower base part (212), and an air core region (218) surrounded by the upper base part (211), the lower base part (212) and the two leg parts (213 and 214), each of the magnetic coils (210) has a trapezoidal shape in a plan view, both the upper base part (211), the lower base part (212) and the two leg parts (213 and 214) have a linear shape, the two leg parts (213 and 214) are formed to set an angle of less than 90 degrees between the lower base part (212) and each of the leg parts (213 and 214), the upper base part (211) and the lower base part (212) are each aligned on two circumferential lines at different distances from the central axis (C), and each of the two leg parts (213 and 214) has a height difference section for connecting the upper base part (211) and the lower base part (212), and the coil assembly (210AS, 230AS) has a structure in which (i) the coil assembly (210AS, 230AS) is formed by aligning the magnetic coils (210) at regular intervals in a circular direction around the central axis (C); (ii) the magnetic coils (210) are connected in such a manner that any two of the magnetic coils (210) adjacent to each other in the circular direction belong to different phases; (iii) the upper base part (211) of each magnetic coil (210) is housed in the air core region (218) of another of the magnetic coils (210) adjacent to each magnetic coil (210) on one side of the upper base part (211);and (iv) the upper base part (211) and the two leg parts (213 and 214) of each magnetic coil (210) are directed in a circular direction corresponding to those of the upper base part (211) and the two leg parts (213 and 214) of another one of the magnetic coils (210) located adjacent to each magnetic coil (210) on one side of the lower base part (212), without overlapping the corresponding ones of the upper base part (211) and the two leg parts (213 and 214) of the other one of the magnetic coils (210) in a radial direction of the stator (200), wherein; the upper base part (211) is located at a greater distance from the central axis (C) of the rotor (300) than the lower base part (212). [2] Three-phase coreless electrical machine (100), comprising: a rotor (300) containing a permanent magnet (320) and rotating about a central axis (C); and a stator (200) containing a coil arrangement (210AS, 230AS) with a combination of several magnetic coils (210) and aligned concentrically with the rotor (300) across a gap of the rotor (300), wherein each of the magnetic coils (210) is formed as a concentrated winding coil having an upper base part (211) parallel to the central axis (C), a lower base part (212) opposite the upper base part (211), two leg parts (213 and 214) connecting the upper base part (211) and the lower base part (212), and an air core region (218) surrounded by the upper base part (211), the lower base part (212) and the two leg parts (213 and 214), each of the magnetic coils (210) has a trapezoidal shape in a plan view, both the upper base part (211), the lower base part (212) and the two leg parts (213 and 214) have a linear shape, the two leg parts (213 and 214) are formed to set an angle of less than 90 degrees between the lower base part (212) and each of the leg parts (213 and 214), the upper base part (211) and the lower base part (212) are each aligned on two circumferential lines at different distances from the central axis (C), and each of the two leg parts (213 and 214) has a height difference section for connecting the upper base part (211) and the lower base part (212), and the coil assembly (210AS, 230AS) has a structure in which (i) the coil assembly (210AS, 230AS) is formed by aligning the magnetic coils (210) at regular intervals in a circular direction around the central axis (C); (ii) the magnetic coils (210) are connected in such a manner that three of the magnetic coils (210) adjacent to each other in the circular direction belong to different phases; (iii) the respective upper base parts (211) of each two of the magnetic coils (210) adjacent to each other in the circular direction are housed in the air core region (218) of another of the magnetic coils (210) adjacent to the two magnetic coils (210) on one side of the upper base part (211);and (iv) the upper base part (211) and the two leg parts (213 and 214) of each magnetic coil (210) are directed in a circular direction corresponding to those of the upper base part (211) and the two leg parts (213 and 214) of another one of the magnetic coils (210) located adjacent to each magnetic coil (210) on one side of the lower base part (212), without overlapping the corresponding ones of the upper base part (211) and the two leg parts (213 and 214) of the other one of the magnetic coils (210) in a radial direction of the stator (200), wherein; the upper base part (211) is located at a greater distance from the central axis (C) of the rotor (300) than the lower base part (212). [3] The coreless electric machine (100) according to claim 1 or 2, wherein the two leg parts (213 and 214) of each of the magnetic coils (210) contact the two leg parts (213 and 214) of the further other one of the magnetic coils (210) located adjacent to the each magnetic coil (210) on the side of the lower base part (212) in the circular direction. [4] Coreless electric machine (100) according to one of claims 1 to 3, wherein each of the magnetic coils (210) has two coil ends (215 and 216), and the two coil ends (215 and 216) are removed from a coil end part of the lower base part (212). [5] Coil arrangement (210AS, 230AS) with several magnetic coils (210) which are combined in a ring-like pattern, wherein each of the magnetic coils (210) has an upper base part (211) parallel to a central axis (C) of the ring-like shape, a lower base part (212) opposite the upper base part (211), and two leg parts (213 and 214) connecting the upper base part (211) and the lower base part (212), and an air core region (218) surrounded by the upper base part (211), the lower base part (212), and the two leg parts (213 and 214), each of the magnetic coils (210) has a trapezoidal shape in a plan view, both the upper base part (211) and the lower base part (212) and the two leg parts (213 and 214) have a linear shape, the two leg parts (213 and 214) are formed to set an angle of less than 90 degrees between the lower base part (212) and each of the leg parts (213 and 214), the upper base part (211) of each magnetic coil (210) is housed in the air core region (218) of another of the magnetic coils (210) which is adjacent to each magnetic coil (210) on one side of the upper base part (211), the upper base part (211) and the lower base part (212) are each aligned on a first circumferential line and a second circumferential line in the coil arrangement (210AS, 230AS), and at opposite ends of the upper base part (211), the upper base part (211) is connected to the leg parts (213 and 214) at positions on the first circumferential line, and at opposite ends of the lower base part (212), the lower base part (212) is connected to the leg parts (213 and 214) at positions on the second circumferential line, wherein the upper base part (211) is located at a greater distance from the central axis (C) of the rotor (300) than the lower base part (212). [6] Coil assembly (210AS, 230AS) according to claim 5, wherein in a plan view of each of the magnetic coils (210), the upper base part (211) and the lower base part (212) are parallel to each other and the leg parts (213 and 214) extend from the upper base part (211) and lower base part (212) in an obliquely inclined direction. [7] Coil arrangement (210AS, 230AS) according to claim 5 or 6, wherein the lower base part (212) is longer than the upper base part (211), and each of the leg parts (213 and 214) has a height difference portion as a connection between the first circumferential line and the second circumferential line at a position closer to the lower base part (212) than to the upper base part (211). [8] Coil assembly (210AS, 230AS) according to one of claims 5 to 7, wherein the first circumferential line is aligned outside the second circumferential line. [9] Coil arrangement (210AS, 230AS) according to one of claims 5 to 8, wherein the magnetic coils (210) have substantially the same shape. [10] Two-phase coreless electric machine (100), comprising: a slider containing a permanent magnet (320) and moving along a predetermined axis of movement; and a stator (200) containing a coil arrangement (210AS, 230AS) with a plurality of magnetic coils (210) united along the axis of movement, wherein each of the magnetic coils (210) is designed as a concentrated winding coil having an upper base part (211) perpendicular to the axis of movement, a lower base part (212) parallel to and opposite the upper base part (211) and at the same distance from the axis of movement as the upper base part (211), two leg parts (213 and 214) connecting the upper base part (211) and the lower base part (212), and an air core region (218) surrounded by the upper base part (211), the lower base part (212) and the two leg parts (213 and 214), each of the magnetic coils (210) has a trapezoidal shape in a plan view, both the upper base part (211), the lower base part (212) and the two leg parts (213 and 214) have a linear shape, the two leg parts (213 and 214) are formed to set an angle of less than 90 degrees between the lower base part (212) and each of the leg parts (213 and 214), each of the two leg parts (213 and 214) has a height difference portion formed at a position connected to the upper base part (211) or the lower base part (212), and the coil assembly (210AS, 230AS) has a structure in which (i) the coil assembly (210AS, 230AS) is formed by aligning the magnetic coils (210) at regular intervals in a direction of the movement axis; (ii) the magnetic coils (210) are connected in such a manner that any two of the magnetic coils (210) adjacent to each other in the direction of the movement axis belong to different phases; (iii) the upper base part (211) of each magnetic coil (210) is housed in the air core region (218) of another of the magnetic coils (210) adjacent to each magnetic coil (210) on one side of the upper base part (211);and (iv) the upper base part (211) and the two leg parts (213 and 214) of each of the magnetic coils (210) are directed in the direction of the movement axis with corresponding ones of the upper base part (211) and the two leg parts (213 and 214) of the further other one of the magnetic coils (210) which are adjacent to the each magnetic coil (210) on one side of the lower base part (212), without superimposing the corresponding ones of the upper base part (211) and the two leg parts (213 and 214) of the further other magnetic coil (210) in a direction perpendicular to the movement axis, wherein; the upper base part (211) is located at a greater distance from the central axis (C) of the rotor (300) than the lower base part (212). [11] Three-phase coreless electric machine (100), comprising: a slider containing a permanent magnet (320) and moving along a predetermined axis of movement; and a stator (200) containing a coil arrangement (210AS, 230AS) with a plurality of magnetic coils (210) united along the axis of movement, wherein each of the magnetic coils (210) is designed as a concentrated winding coil having an upper base part (211) perpendicular to the axis of movement, a lower base part (212) parallel to and opposite the upper base part (211) and at the same distance from the axis of movement as the upper base part (211), two leg parts (213 and 214) connecting the upper base part (211) and the lower base part (212), and an air core region (218) surrounded by the upper base part (211), the lower base part (212) and the two leg parts (213 and 214), each of the magnetic coils (210) has a trapezoidal shape in a plan view, both the upper base part (211), the lower base part (212) and the two leg parts (213 and 214) have a linear shape, the two leg parts (213 and 214) are formed to set an angle of less than 90 degrees between the lower base part (212) and each of the leg parts (213 and 214), each of the two leg parts (213 and 214) has a height difference portion formed at a position connected to the upper base part (211) or the lower base part (212), and the coil assembly (210AS, 230AS) has a structure in which (i) the coil assembly (210AS, 230AS) is formed by aligning the magnetic coils (210) at regular intervals in a direction of the movement axis; (ii) the magnetic coils (210) are connected in such a manner that three of the magnetic coils (210) that are adjacent to each other in the direction of the movement axis belong to different phases; (iii) the respective upper base parts (211) of each two of the magnetic coils (210) that are adjacent to each other in the direction of the movement axis are housed in the air core region (218) of another of the magnetic coils (210) that is adjacent to the two magnetic coils (210) on one side of the upper base part (211);and (iv) the upper base part (211) and the two leg parts (213 and 214) of each of the magnetic coils (210) are directed in the direction of the movement axis with corresponding ones of the upper base part (211) and the two leg parts (213 and 214) of the further other one of the magnetic coils (210) which are adjacent to the each magnetic coil (210) on one side of the lower base part (212), without superimposing the corresponding ones of the upper base part (211) and the two leg parts (213 and 214) of the further other magnetic coil (210) in a direction perpendicular to the movement axis, wherein; the upper base part (211) is located at a greater distance from the central axis (C) of the rotor (300) than the lower base part (212). [12] Coreless electric machine (100) according to any one of claims 1-4 and 10-11, wherein a coil lead wire (410) used to form each of the magnetic coils (210), a lead wire bundle (422) as a bundle of a plurality of non-insulated lead wires (421), all made of non-insulated wire, and an insulating coating layer (424) covering the periphery of the lead wire bundle (422), and the conductor wire bundle (422) is braided.

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