Coil and coil manufacturing method

Abstract

To provide a coil having a high space factor while ensuring a necessary dielectric strength voltage. [Solution] The air-core coil 101A, which is arranged along the movement direction of the magnet of the electromechanical device, comprises a substrate 10, a first insulating layer 50 formed around a substrate bundle 30 bundling a plurality of substrates 10 so as to be in contact with the substrate 10 when viewed in cross section, and a second insulating layer 70 formed around the winding group 61 so as to surround the winding group 61 formed by windings 41a, 41b wound around the air-core region 90A.

Description

[Technical Field]

[0001] The present invention relates to a coil for a coreless electromechanical device and a method for manufacturing the coil. [Background technology]

[0002] Coils for use in coreless electromechanical devices are known.

[0003] FIG. 11 is a diagram for explaining conventional coils 901 and 902. In FIG. 11(a) is a schematic diagram of a coil group formed by sequentially connecting multiple coils 901, 902. Here, the coreless electromechanical device is assumed to be a two-phase coreless motor, and only the coil group related to phase A is shown as an example. Each of the coils 901, 902 has a winding 940, 940' wound around an air-core region 990. Here, the winding 940, 940' is wound approximately two times, with the first and second windings stacked in two layers. The symbol PL1 indicates an imaginary plane perpendicular to the longitudinal direction of the winding 940, 940'.

[0004] Fig. 11(b) is a cross-sectional view of conventional coil 901 when cutting coil 901 along imaginary plane PL1 shown in Fig. 11(a) and viewing the cut surface along arrow A. As shown in Fig. 11(b), conventional coil 901 uses magnet wires 914a, each of which is coated with an insulating coating 950 on a substrate 910 made of a conductive material. In the example shown, multiple magnet wires 914a are twisted together, and multiple twisted units are braided to form braided wire 924, which forms winding 940 (conventional first winding 940).

[0005] Figure 11(c) is a cross-sectional view of another conventional coil 902 taken along imaginary plane PL1 shown in Figure 11(a) and viewed along arrow A. As shown in Figure 11(c), another conventional coil 902 uses a braided wire 924' formed by bundling, twisting, and braiding bare copper wires 912 made of conductive material. An insulating coating layer 950' is formed around the braided wire 924' to form a unit winding 940' (a second conventional winding 940'). Incidentally, a similar conventional second winding 940' is also described in Patent Document 1 (FIG. 11) and Patent Document 2 (FIG. 7). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2018 / 139245 [Patent Document 2] International Publication No. 2018 / 139246 Summary of the Invention [Problem to be solved by the invention]

[0007] Now, if the electromechanical device is, for example, a motor, the coils described above are arranged at positions set as "poles" of the stator. When adjacent coils are arranged at close intervals, the windings of the adjacent coils are also close to each other. Therefore, it is necessary to ensure a high withstand voltage (hereinafter sometimes simply referred to as "dielectric withstand voltage") between these windings. For this reason, in order to ensure a sufficient dielectric strength, the thickness of the insulating coating 950 in the conventional first winding 940 is set to be relatively large. Accordingly, the proportion of the cross-sectional area occupied by the insulating coating 950 (insulating layer) is also large in the first winding 940, which is made up of a large number of substrates 910 coated with the insulating coating 950. In other words, the proportion of the cross-sectional area of ​​the conductor is relatively small, resulting in a low "space factor" (see FIG. 11(b)). Similarly, in the conventional second winding 940', the thickness of the insulating coating layer 950' (insulating layer) is set to be large in order to ensure a sufficient dielectric strength, resulting in a low space factor (see FIG. 11(c)). In other words, in the conventional coils 901 and 902, the space factor is reduced in exchange for ensuring the necessary dielectric strength voltage.

[0008] The present invention has been made in view of the above circumstances, and has an object to provide a coil that has a high space factor while ensuring the necessary dielectric strength voltage. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided an air-core coil arranged along the direction of movement of a magnet of an electromechanical device, the coil comprising: a substrate made of a conductive material; a first insulating layer made of an insulating material and formed around a substrate bundle formed by bundling a plurality of the substrates so as to be in contact with the substrate when the coil is cut along an imaginary plane perpendicular to the longitudinal direction of the substrate and viewed on the cross section; and a second insulating layer made of an insulating material and formed around a "winding group" formed by windings wound around an air-core region so as to surround the winding group when the "winding" formed by the substrate bundle and the first insulating layer formed around the substrate bundle is cut along an imaginary plane perpendicular to the longitudinal direction of the winding and viewed on the cross section of the winding.

[0010] According to another aspect of the present invention, there is provided a method for manufacturing an air-core coil arranged along the direction of movement of a magnet of an electromechanical device. The method for manufacturing such a coil includes, in this order, a substrate bundle preparation process of bundling together a plurality of bare conductor wires as the substrate to prepare the substrate bundle; a substrate bundle forming process of winding the substrate bundle around the air-core region to form the substrate bundle; a first insulating layer forming process of forming the first insulating layer made of an insulating material around the formed substrate bundle so that it is in contact with the substrate; and a second insulating layer forming process of forming the second insulating layer made of an insulating material around the "winding group" made of windings formed by the substrate bundle and the first insulating layer so that it surrounds the winding group.

[0011] In the above-mentioned coil manufacturing method, it is preferable that the first insulating layer forming process includes, in this order, an infiltration step of infiltrating a water-soluble material into the substrate bundle, and a solidification step of solidifying the infiltrated water-soluble material. [Effects of the Invention]

[0012] The coil of the present invention has a high space factor while ensuring the necessary dielectric strength. Furthermore, the coil manufacturing method of the present invention makes it possible to manufacture a coil having a high space factor while ensuring the necessary dielectric strength. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view for explaining coils 101A and 101B (sometimes referred to as first-shape coil 101A and second-shape coil 101B) according to embodiment 1, and a first coil subassembly 101AS, a second coil subassembly 101BS, and a coil assembly 100 each composed of multiple coils 101A and 101B. [Figure 2] 1A and 1B are diagrams illustrating a coil 101A according to the first embodiment. [Figure 3] 4A to 4C are manufacturing process diagrams shown to explain a manufacturing method of the coil 101A according to the first embodiment. [Figure 4] 10A and 101B according to the first embodiment are diagrams illustrating the effects of the coils 101A and 101B. [Figure 5] 10A and 10B are diagrams illustrating a coil 102A according to a second embodiment. [Figure 6] 10A to 10C are manufacturing process diagrams shown to explain a manufacturing method of a coil 102A according to the second embodiment. [Figure 7] FIG. 1 is a schematic diagram showing an experimental configuration in an experimental example. [Figure 8] 10 is a table showing experimental results in an experimental example. [Figure 9] 10A and 10B are diagrams illustrating a coil 103A according to a first modification. [Figure 10] 10 is a diagram for explaining a coil 104A according to a second modification. FIG. [Figure 11] FIG. 10 is a diagram illustrating conventional coils 901 and 902. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of a coil and a method of manufacturing a coil according to the present invention will be described with reference to the drawings. Each drawing is a schematic diagram showing an example, and does not necessarily strictly reflect the actual dimensions, ratios, etc.

[0015] [Embodiment 1] 1. Configuration of coils 101A and 101B according to embodiment 1 (1) Overview of Coils 101A, 101B and Coil Assembly 100 The coils 101A and 101B according to the first embodiment are air-core coils arranged along the direction of movement of the magnet of the electromechanical device. The electromechanical device to which the coils 101A and 101B are applied may be any electromechanical device that uses an air-core coil, and a so-called coreless motor is one suitable application. Fig. 1(a) is a perspective view showing an example of a coil assembly 100 used in a coreless motor. Here, multiple coils 101A, 101B (numbers in subscripts are index numbers) are arranged along the direction of movement ROT of a permanent magnet (not shown) of a rotor to form the coil assembly 100. In other words, the coil assembly 100 is configured by arranging the multiple coils 101A, 101B so that the effective coil portions of the respective coils 101A, 101B (reference numeral 84A in Fig. 1(d) and reference numeral 84B in Fig. 1(e)) are perpendicular to the direction of movement ROT of the magnet. 1(a), the direction parallel to the rotation axis AX1 of the coreless motor is the y direction, the direction perpendicular to the rotation axis is the x direction, and the direction perpendicular to the x and y directions is the z direction. The same directional definitions (x direction, y direction, z direction) are also used for the coils 101A and 101B arranged according to these directional definitions.

[0016] 1(d) is a perspective view showing the appearance of the coil 101A (first shape coil). As shown in the figure, the coil 101A is an air-core coil. 1(d) mainly shows the outer shape of the coil 101A and does not clearly show its internal structure. However, when tracing the coil 101A from the coil end 85A side, the coil 101A is formed in the following order: effective coil portion 84A (lower section), first coil end portion 81A (lower section), effective coil portion 84A (lower section), second coil end portion 82A, effective coil portion 84A (upper section), first coil end portion 81A (upper section), and effective coil portion 84A (upper section), leading to coil end 86A. As described above, the coil 101A is configured by forming the windings 41a and 41b (see FIG. 2, described later) so that they are wound around the air-core region 90A approximately two times (strictly speaking, approximately 1.75 times). Note that the coil 101A, which serves as a first-shape coil, has a stepped shape in which the first coil end portion 81A is offset radially inward from the effective coil portion 84A (toward the rotation axis AX1 when the coils are arranged). An "air-core coil" can also be defined as a type of coil in which a conductive material is wound around the coil, and in which no iron core serving as a salient pole is disposed inside the winding. In this context, "winding" includes winding that completely surrounds the air-core region over 360°, as well as winding that surrounds the air-core region but does not go all the way around (less than 360°).

[0017] 1(e) is a perspective view showing the appearance of coil 101B (second-shape coil). As shown in the figure, coil 101B as a second-shape coil differs from coil 101A (first-shape coil) in that second coil end portion 82B has a stepped shape offset radially outward from effective coil portion 84B. In other respects, coil 101B basically has the same configuration as coil 101A (first-shape coil).

[0018] 1(b) is a perspective view of the first coil subassembly 101AS. The first coil subassembly 101AS can be formed by arranging N (N is a natural number; in this case, 8) coils 101A (first shape coils) in a ring shape with the outer surfaces of the effective coil portions 84A of adjacent coils 101A (first shape coils) in contact with each other, and then adhering them to each other. 1(c) is a perspective view of the second coil subassembly 101BS. The second coil subassembly 101BS can be formed by arranging N (eight in this example) coils 101B (second-shape coils) in a ring shape with the outer surfaces of the effective coil portions 84B of adjacent coils 101B (second-shape coils) in contact with each other, and then adhering them to each other.

[0019] After preparing the first coil subassembly 101AS and the second coil subassembly 101BS as described above, the coil assembly 100 (see Figure 1(a)) can be constructed by sliding the second coil subassembly 101BS (Figure 1(c)) from the right side to the left side of the first coil subassembly 101AS (Figure 1(b)) and combining them.

[0020] (2) Cross section of coil 101A In the following explanations (Embodiment 1, Embodiment 2, Modification 1 and Modification 2), of the two types of coils 101A and 101B having different shapes, coil 101A, which is a first shape coil, will be taken as a representative and its cross-sectional structure and the like will be explained. The embodiments described below are also applicable to coil 101B, which is a second shape coil, and are further applicable to coils in cases where a coil assembly can be realized using only one type of coil shape (see, for example, Patent Document 2).

[0021] The left side of FIG. 2(a) is a plan view of the coil 101A as viewed along the -z direction, and the right side of FIG. 2 is a right side view of the coil 101A as viewed along the -x direction. In the figure, a pattern resembling a braided wire is drawn on the surface, but the braided wire is not actually exposed. The pattern in the figure is a pattern of the second insulating layer 70 formed to resemble the pattern of the braided wire. FIG. 2(b) is a cross-sectional view of a key portion of the coil 101A taken along the line BB in the left side of FIG. 2(a). That is, FIG. 2(b) is also a view of the cross section of the coil 101A taken along an imaginary plane perpendicular to the longitudinal direction of the substrate 10 (described below) (corresponding to the imaginary plane PL1 in FIG. 1(d)). For ease of explanation, Fig. 2(a) is depicted as a structure without a step on the side of the first coil end portion 81A (not shown), as in Fig. 5(a), Fig. 9(a), and Fig. 10(a) below.

[0022] As shown in FIG. 2(b), the coil 101A includes a substrate 10, a first insulating layer 50, and a second insulating layer 70 as basic components.

[0023] (3) Structure of the conductor portion based on the substrate 10 The substrate 10 is a component made of a conductive material. Any conductive material may be used for the substrate 10. In the first embodiment, for example, a "copper wire" made primarily of copper, a "carbon wire" made of carbon, or a "plated wire" made of copper or the like that is plated with nickel or tin may be used.

[0024] The thickness of the substrate 10 can be selected appropriately depending on the specifications of the electromechanical device. In the first embodiment, the average radius of the substrate 10 is preferably 100 μm or less. Furthermore, the average radius of the substrate 10 is more preferably 50 μm or less. As will be described in detail in the section "Experimental Examples," the use of a substrate 10 having such a diameter can reduce the generation of eddy currents.

[0025] In the example of Fig. 2(b), bare conductor wires 12 (e.g., bare copper wires) are used as the substrate 10, and six of these bare conductor wires 12 are twisted together to form a stranded wire 20 as an intermediate material. Three sets of such stranded wires 20 are then braided to form a braided wire 24. The unit of braided wire 24 here is both the unit of the "conductor portion" of the winding 41 and the unit of the "substrate bundle 30."

[0026] The term "substrate bundle 30" refers to a unit obtained by bundling multiple substrates 10. The term "bundled" as a substrate bundle includes both a first embodiment in which multiple bare substrates (bare conductor wires such as bare copper wires) are directly bundled together, as in the first embodiment, and a second embodiment in which primary insulated substrates with a first insulating layer (described below) are indirectly bundled together. The term "bare conductor wire," "bare copper wire," or the like as used herein refers to a wire that is not coated with an insulating material and in which the conductor, which is a conductive member, is exposed. Examples include bare copper wire, nickel-plated wire, tin-plated wire, and carbon wire.

[0027] Furthermore, in embodiment 1, for example, a "substrate bundle 30" can be a bundle of multiple substrates 10 that are kept straight, but considering that bending stress will be applied when the substrates are later formed into a winding, it is preferable to use a "substrate bundle 30" that is made by twisting or twisting the substrates 10 (for example, Litz wire) or braiding the substrates (braided wire).

[0028] In addition, in the first embodiment, the substrate bundle 30 is preferably made of a braided wire 24 in which a plurality of bare conductor wires 12 (substrates 10) are braided together. As will be described in detail in the section on Experimental Examples, the use of a substrate bundle 30 having such a configuration can reduce the generation of eddy currents.

[0029] (4) First insulating layer 50 The first insulating layer 50 is made of an insulating material and is formed so as to be in contact with the substrate 10 when the coil 101 is cut along an imaginary plane perpendicular to the longitudinal direction of the substrate 10 and the cut surface is viewed. The first insulating layer 50 is also formed around a substrate bundle 30 that bundles together multiple substrates 10 (see FIG. 2(b)). A small amount of the first insulating layer 50 may be interposed between the bare conductor wires 12 that make up the braided wire 24. The bare conductor wires 12 that make up the braided wire 24 may also be in contact with each other. Here, "cutting the coil on an imaginary plane perpendicular to the length direction of the substrate 10" can also be expressed as "cutting the coil on an imaginary plane perpendicular to the length direction of the windings 41a and 41b," which will be described later. The opposite is also possible. Because the substrate 10 may be twisted or braided as described above, the length direction of the substrate 10 does not necessarily coincide with the length direction of the windings 41 from a microscopic perspective. However, the cross-sectional area of ​​the substrate 10 is often smallest when cut along the length direction of the windings 41. Therefore, "cutting the coil on an imaginary plane perpendicular to the length direction of the windings 41" can be considered to be "cutting the coil on an imaginary plane perpendicular to the length direction of the substrate 10." Furthermore, with respect to the effective coil portion 84A, "cutting the coil on an imaginary plane perpendicular to the length direction of the substrate 10" can also be expressed as "cutting the coil on an imaginary plane perpendicular to the y direction."

[0030] The first insulating layer 50 may be made of any insulating material. In the first embodiment, the first insulating layer 50 is preferably an insulating layer formed by solidifying a water-soluble material that has permeated the periphery of the substrate 10 made of the bare conductor wire 12. In this case, the first insulating layer 50 is more preferably an electrodeposited insulating coating formed around the periphery of the substrate 10 made of the bare conductor wire 12. In other words, the first insulating layer 50 here is an "electrodeposited insulating coating" obtained by electrodeposition coating the substrate 10 of the bare conductor wire 12. The electrodeposited insulating coating as the first insulating layer 50 coats the bare conductor wire 12, is made of an insulating material, and has an insulating function.

[0031] On the other hand, it is also preferable that the first insulating layer 50 is an insulating coating film formed around the substrate 10 made of bare conductor wires 12. This is because the first insulating layer 50 can be formed relatively inexpensively, and an economically advantageous coil 101 can be obtained. In other words, the first insulating layer 50 here is an "insulating coating film (excluding electrodeposited insulating coating film)" obtained by applying an insulating coating material to the substrate 10. The insulating coating film as the first insulating layer 50 coats the bare conductor wires 12, is made of an insulating material, and has an insulating function.

[0032] (5) Winding 41 and Winding Group 61 The "winding 41" is composed of the substrate bundle 30 and the first insulating layer 50 formed around the substrate bundle 30. For reference, this unit of the "winding 41" is a unit of a shape wound around the air-core region 90A. In the illustrated example, the winding 41 is formed so as to be wound around the air-core region 90, and as a result, in the effective coil portion 84A, the windings are stacked such that the winding 41a is located in the upper tier and the winding 41b is located in the lower tier (the +z direction is defined as "up"). In the illustrated example, the "winding group 61" is composed of the winding 41a and the winding 41b. However, the term "winding group" as used herein is intended to be included in the concept of "winding group" whether or not the winding is wound multiple times around the air-core region 90A. For example, windings in a single layer, in which the windings are not stacked, such as winding group 63 in [Modification 1] and winding group 64 in [Modification 2], which will be described later, are also included in the concept of "winding group" as used herein.

[0033] (6) Second insulating layer 70 The second insulating layer 70 is made of an insulating layer material. When the "winding 41" is cut along an imaginary plane PL1 perpendicular to the longitudinal direction of the winding 41 and the cross section of the winding 41 is viewed (in other words, when the coil 101A is cut along an imaginary plane PL1 perpendicular to the longitudinal direction of the substrate 10 and the cross section is viewed), the second insulating layer 70 is formed around the "winding group 61" formed by winding the winding 41 around the air-core region 90 so as to surround the winding group 61. In other words, when the windings 41 are bundled together, the second insulating layer 70 is further formed around the bundle of windings 41 (winding group 61). 2(b), the winding 41a and the winding 41b are depicted as having a small amount of the second insulating layer 70 between them. However, this is not limited to this. Only the first insulating layer 50 constituting each winding may be interposed between the winding 41a and the winding 41b, and almost no second insulating layer 70 may be interposed.

[0034] The second insulating layer 70 may be made of any insulating material. Here, the second insulating layer 70 is an insulating coating film made of an insulating coating material such as varnish. However, the second insulating layer 70 is not limited to this. The second insulating layer 70 is preferably an insulating layer formed by curing a member that has insulating and adhesive properties. In other words, the second insulating layer 70 not only serves the purpose of insulation, but also serves the purpose of adhering the windings 41a and 41b together and fixing the formed shape, as is clear from the state of the winding group 61 in Fig. 3(v) described below.

[0035] In the first embodiment, it is preferable that the withstand voltage of the second insulating layer 70 is greater than the withstand voltage of the first insulating layer 50. In other words, it is preferable that the first insulating layer 50 and the second insulating layer 70 are formed so as to satisfy the relationship (withstand voltage of the second insulating layer 70)>(withstand voltage of the first insulating layer 50). In yet another way, it is preferable that the second insulating layer 70 and the first insulating layer 50 are configured so that the first insulating layer 50 mainly provides insulation under conditions where the potential difference between the poles is relatively low, and the second insulating layer 70 mainly provides insulation under conditions where the potential difference between different phases is relatively high. As a specific construction method, for example, when the first insulating layer 50 and the second insulating layer 70 are made of the same material, the first insulating layer 50 and the second insulating layer 70 may be formed so that the thickness of the second insulating layer 70 is greater than the thickness of the first insulating layer 50 when viewed in cross section. By setting the withstand voltages of the first insulating layer 50 and the second insulating layer 70 in this manner, the withstand voltage ED2 required between the windings of adjacent coils is ensured mainly by the second insulating layer, while the thickness of the first insulating layer can be reduced to the minimum necessary to ensure the withstand voltage ED1 required between the windings of the same coil, thereby further increasing the space factor.

[0036] As another construction method, for example, the thicknesses of both insulating layers may be made approximately the same, and the materials for both insulating layers may be selected so that a material with relatively high voltage resistance characteristics (a material with low conductivity) is used for the second insulating layer 70 and a material with relatively low voltage resistance characteristics is used for the first insulating layer 50.

[0037] However, in embodiment 1, it is not prohibited to configure the coil so as to satisfy the relationship (withstand voltage of second insulating layer 70)≦(withstand voltage of first insulating layer 50), and such a configuration is also included in embodiment 1.

[0038] 2. Manufacturing Method of Coil 101A According to Embodiment 1 FIG. 3 is a manufacturing process diagram for explaining a manufacturing method of the coil 101A according to the first embodiment. Roughly speaking, the manufacturing method of the coil 101A includes a substrate bundle preparation step, a substrate bundle forming step, a first insulating layer formation step, and a second insulating layer formation step, in this order.

[0039] (1) Base material bundle preparation process The substrate bundle preparation process is a process in which a plurality of bare conductor wires 12 serving as substrates 10 are bundled by twisting, braiding, or the like to prepare a "substrate bundle 30." Specifically, for example, six bare conductor wires 12 are twisted together to create a stranded wire 20, which serves as an intermediate material (see FIG. 3(i)). Three sets of such stranded wires 20 are then braided to create a braided wire 24 (see FIG. 3(ii)). The braided wire 24 serves as the substrate bundle 30.

[0040] (2) Substrate bundle forming process The substrate bundle forming process is a process of winding the substrate 10 around the air-core region 90A (not shown in FIG. 3) to form the substrate bundle 30. Specifically, for example, aiming for a shape as shown in FIG. 1(d), the substrate bundle 30 (braided wire 24) is wound around the air-core region 90A, and the shapes of the effective coil portion 84A, first coil end portion 81A, second coil end portion 82A, etc. are adjusted to form the substrate bundle 30. The cross section immediately after the substrate bundle forming process has been performed has a shape in which the substrate bundle 30 is stacked in two layers (see (iii) in FIG. 3).

[0041] After the substrate bundle forming is completed, the coil ends 85A, 86A (see Figure 1(d)) are masked in advance by applying a penetrating insulating coating material such as polyesterimide, polyamideimide, polyimide, enamel, urethane, or varnish. This prevents the insulating material around the substrate bundle from being affected in the first insulating layer forming process and the second insulating layer forming process described below. The masking can be selectively removed by heating in a soldering furnace after the second insulating layer forming process is completed.

[0042] (3) First insulating layer formation process The first insulating layer forming step is a step of forming a first insulating layer 50 made of an insulating material around the substrate 10 on the substrate bundle 30 formed in the substrate bundle forming step so as to be in contact with the substrate 10 (see (iv) of Figure 3). Specifically, the formed upper and lower substrate bundles 30 are separated by a jig or the like to create a gap, and the first insulating layer 50 is formed independently on the upper and lower substrate bundles 30, respectively.

[0043] Although not shown in the drawings, the first insulating layer is preferably formed by performing, in this order, a permeation step in which a water-soluble material (a solute having insulating properties is preferably used here) is permeated into the base material bundle 30, and a solidification step in which the permeated water-soluble material is solidified. In this case, it is more preferable that the water-soluble material has insulating properties and adhesive properties.

[0044] For example, a liquid tank, container, or the like (hereinafter simply referred to as a liquid tank) is filled with a thermosetting resin solution, and then an upper layer of substrate bundle 30 or a lower layer of substrate bundle 30 separated by a jig or the like is placed inside the liquid tank. This causes the water-soluble material to penetrate (permeate) between the multiple substrates 10 that make up the substrate bundle 30. The substrate bundle 30 is then pulled out of the liquid tank with the water-soluble material adhering to the periphery of the substrates 10. The substrate bundle 30 is heated to solidify the material derived from the water-soluble material adhering to the periphery of the substrates 10. The above-described manufacturing method may be employed.

[0045] It is more preferable that the penetration and solidification of the water-soluble material be carried out by so-called electrodeposition insulating coating. For example, a liquid tank is filled with an aqueous solution containing a water-soluble material, and the upper or lower substrate bundle 30 (substrates) separated by a jig or the like is placed inside the liquid tank so that it is completely submerged. This allows the water-soluble material to penetrate (permeate) between the multiple substrates 10 that make up the substrate bundle 30. In this state, a DC voltage is applied between the substrate and the electrode to control the thickness of the insulating coating, and an electrodeposited insulating coating film derived from the water-soluble material is deposited around the substrate bundle 30 (microscopically, the substrates 10 that make up the substrate bundle 30). This forms a first insulating layer 50 made of an electrodeposited insulating coating film around the substrate 10, which is made of bare conductor wires 12. The above-mentioned manufacturing method may also be employed. When applying the DC voltage, ultrasonic waves may be applied to the aqueous solution in the liquid tank. By applying ultrasonic waves, air bubbles and impurities can be removed from around the substrate 10, thereby improving the insulation quality.

[0046] The formation of the first insulating layer 50 is not limited to the above-described electrodeposition insulating coating. For example, although not shown, a method may be employed in which an insulating material is applied to the periphery of the substrate 10 made of the bare conductor wires 12 to form an insulating coating film, and the insulating coating film serves as the first insulating layer 50. This method of forming an insulating coating film by application can form the first insulating layer 50 more inexpensively than when using electrodeposition insulating coating, and an economically advantageous coil can be obtained.

[0047] (4) Second insulating layer formation process The second insulating layer forming step is a step of forming a second insulating layer 70 made of an insulating material around the "winding group 61" consisting of the windings 41a, 41b formed by the substrate bundle 30 and the first insulating layer 50 so as to surround the winding group 61 (see FIG. 3(v)). Specifically, first, the upper substrate bundle 30 (winding 41a) on which the first insulating layer has been formed and the lower substrate bundle 30 (winding 41b) on which the first insulating layer has also been formed are stacked to eliminate any gaps between them. Next, an insulating coating material such as varnish is applied so as to surround the winding group 61, forming an insulating coating film. This allows the second insulating layer 70 to be formed. The second insulating layer forming step also serves the purpose of bonding the windings 41a and 41b together with the second insulating layer 70, and fixing the shape of the formed coil 101A. By carrying out the above steps, the coil 101A can be obtained.

[0048] 3. Effects of the coil 101A and coil manufacturing method according to the first embodiment The coil 101A and the method for manufacturing the coil 101A according to the first embodiment have the above-described configuration, and therefore can achieve the following effects.

[0049] (1) Ensuring dielectric strength and improving space factor Fig. 4(a) is a schematic diagram showing the connection state of coils 101A and 101B according to embodiment 1. The figure shows an example of a two-phase coreless motor that operates by being excited by two phases, A and B. Fig. 4(b) is a cross-sectional view of windings belonging to adjacent coils cut along an imaginary plane PL2 in Fig. 4(a).

[0050] First, we will briefly explain the issue of dielectric strength in two-phase coreless motors. The coils of the coil assembly 100 shown in FIG. 1(a) can be connected as shown in FIG. 4(a), for example. 4(a), N (N=8) coils 101A are electrically connected in sequence between coil terminals 151 and 152 to form phase A (a group of phase A coils). Similarly, N (N=8) coils 101B are electrically connected in sequence between coil terminals 153 and 154 to form phase B (a group of phase B coils). In this case, the coils belonging to phase A and the coils belonging to phase B are arranged adjacent to each other in the respective effective coil portions 84A and 84B.

[0051] For example, if an A-phase voltage Va is applied to the A-phase terminal, the potential difference across one coil 101A is simply calculated as Va / N. Here, we will continue the explanation by focusing on the leftmost coil 101A1 among the A-phase coils. For example, when a higher potential is applied to coil terminal 151 than to coil terminal 152, the potential of the conductor portion of winding 41b near arrow D2 of coil 101A1 drops by Va / N relative to the potential of the conductor portion (substrate bundle 30, substrate 10) of winding 41a near arrow D1. Therefore, the potential difference within one coil 101A1 is Va / N. Therefore, within one coil 101A1, it is sufficient to ensure a dielectric strength voltage ED1 corresponding to a voltage of Va / N between the windings constituting the same coil. Note that, to account for inrush current and other factors, the set value of dielectric strength ED1 is actually set to a value greater than Va / N. On the other hand, when considering adjacent coils, if excitation voltages of different phases are applied to adjacent coils, a potential difference equivalent to, for example, Va may occur between the conductor parts in the windings of the adjacent coils. Therefore, it is necessary to ensure a dielectric strength voltage corresponding to at least the voltage Va between the "windings of adjacent coils."

[0052] 11, the thickness of the insulating layer (insulating coating 950, insulating coating layer 950') was carefully set large so as to ensure the relatively high dielectric strength voltage required between the windings of adjacent coils. As a result, the space factor of conventional coils 901, 902 was low.

[0053] On the other hand, in the coil 101 according to the first embodiment shown in FIGS. 1 to 4, the first insulating layer 50 is configured to be "formed around the substrate bundle 30, which is a bundle of multiple substrates 10, so as to be in contact with the substrates 10." This ensures that the first insulating layer 50 is interposed between the conductor portions of multiple windings constituting the same coil. For example, as shown in FIG. 4(b), the first insulating layer 50 can be reliably interposed between the conductor portion (substrate bundle 30, substrate 10) of the winding 41a stacked in the upper layer and the conductor portion (substrate bundle 30, substrate 10) of the winding 41b in the lower layer constituting the same coil 101A1. Therefore, the first insulating layer 50 can ensure the necessary dielectric strength voltage ED1 between "windings that constitute the same coil."

[0054] Furthermore, in the coil 101 according to embodiment 1, the second insulating layer 70 is "formed around the 'winding group' formed by windings wound around the air-core region so as to surround the winding group," so that when multiple coils 101A, 101B are arranged as shown in Figure 1(a) or Figure 4(a), in addition to the first insulating layer 50, the second insulating layer 70 can also be interposed between the "windings of adjacent coils." Therefore, the first insulating layer 50 and the second insulating layer 70 can ensure a relatively high dielectric strength voltage ED2 required between "windings of adjacent coils." Furthermore, when viewed from the substrate bundle 30, there is a double layer of insulation (double insulation) between the substrate bundle 30 of the adjacent coil winding, in addition to the first insulating layer 50, the second insulating layer 70. Therefore, even if a reverse surge occurs in either the substrate bundle 30 or the substrate bundle 30 of the adjacent coil winding, no insulation breakdown will occur between these substrate bundles 30, resulting in extremely safe coils 101A, 101B.

[0055] Furthermore, considering the first insulating layer 50 of the first embodiment, (i) while a conventional insulating layer needs to ensure not only the dielectric strength voltage ED1 required between the windings of the same coil but also the dielectric strength voltage ED2 required between the windings of adjacent coils, which has a relatively large value, the first insulating layer 50 of the first embodiment basically only needs to consider the dielectric strength voltage ED1, and (ii) the required dielectric strength voltage ED1 is generally lower (smaller) than the dielectric strength voltage ED2, it is not necessary to set the thickness of the first insulating layer 50 of the first embodiment as thick as that of a conventional insulating layer. In other words, the thickness of the first insulating layer 50 can be reduced to a considerable extent compared to the thickness of the insulating layers (insulating coating 950, insulating coating layer 950') in the conventional coils 901 and 902. In addition, when considering the thickness of the second insulating layer 70, since not only the second insulating layer 70 but also the first insulating layer 50 are already interposed between the windings of adjacent coils as described above, it is not necessary to set the thickness of the second insulating layer 70 as thick as that of conventional insulating layers. Therefore, the cross-sectional area of ​​the second insulating layer 70 itself does not have a significant impact on the increase in the cross-sectional area of ​​the entire coil 101. Since the cross-sectional areas of the first insulating layer 50 and the second insulating layer 70 can be reduced in this manner, the space factor, which is the ratio of the cross-sectional area of ​​the conductor portion (substrate bundle 30) to the entire coil 101, can be increased more than before.

[0056] As described above, the coil 101 according to the first embodiment is a coil that has a high space factor while ensuring the necessary dielectric strength voltage.

[0057] Increasing the space factor leads to more efficient conductor placement, which reduces the resistance of the coil, thereby reducing heat generation and contributing to increased energy efficiency of the electromechanical device. Furthermore, by forming the second insulating layer 70 on the outside of the first insulating layer 50 to double the insulation, even if there is variation in the insulating quality of the first insulating layer 50 (due to air bubbles, impurities, etc.), the second insulating layer 70 arranged on the outside contributes to maintaining and improving the insulating quality of the entire coil.

[0058] (2) The second insulating layer 70 of the first embodiment is preferably an insulating layer formed by curing a member that has insulating and adhesive properties. With this configuration, the windings 41a and 41b are firmly integrated into a coil, and the formed shape is less likely to be distorted.

[0059] (3) In the first embodiment, the first insulating layer 50 is preferably an insulating layer formed by solidifying a water-soluble material that has permeated the periphery of the substrate 10 made of the bare conductor wires 12 . If the first insulating layer 50 were constructed as an insulating coating film coated with an insulating coating material, it would be susceptible to dripping during application and uneven adhesion of the coating material to the substrate. On the other hand, by constructing the first insulating layer 50 as an "insulating layer formed by solidifying a water-soluble material that has permeated around the substrate 10 of the bare conductor wire 12," the permeation effect allows the water-soluble material to reach the gaps between the substrates within the substrate bundle 30, filling the gaps between the substrates. This prevents dripping, uneven adhesion, and other problems, resulting in a uniform insulating layer regardless of the location on the coil. This results in uniform dielectric strength characteristics regardless of the location on the coil, resulting in a high-quality coil with stable insulation characteristics.

[0060] (4) In the first embodiment, the first insulating layer 50 is an insulating layer formed by solidifying a water-soluble material that has permeated the periphery of the substrate 10 consisting of the bare conductor wire 12, and it is more preferable that the first insulating layer 50 is an electrodeposited insulating coating film formed around the periphery of the substrate 10 consisting of the bare conductor wire 12. An electrodeposition coating film is generally formed by completely immersing the object to be coated (here, the substrate bundle 30) in an electrodeposition coating solution and applying a predetermined voltage. The electrodeposition coating solution penetrates the substrate bundle 30 so as to reach both the outside and the inside, and voltage is applied not only to the substrates 10 located on the outside of the substrate bundle 30 but also to the substrates 10 located on the inside, resulting in a first insulating layer 50 that is uniform from the outside to the inside of the substrate bundle 30. Therefore, the first insulating layer 50 is formed not only on the outside of the substrate bundle 30 but also in the gaps between the substrates 10 on the inside, making it possible to obtain more uniform dielectric strength characteristics regardless of the location of the coil, resulting in a high-quality coil with stable insulation characteristics.

[0061] (5) As described above, the method for manufacturing the coil of embodiment 1 includes, in this order, a substrate bundle preparation process, a substrate bundle forming process, a first insulating layer formation process for forming a first insulating layer 50 made of an insulating material around the substrate 10 so as to contact the substrate 10, and a second insulating layer formation process for forming a second insulating layer 70 made of an insulating material around the winding group 61 so as to surround the winding group 61. This allows the first insulating layer 50 to be reliably interposed between the conductor portions of multiple windings that make up the same coil, and in addition to the first insulating layer 50, the second insulating layer 70 can also be interposed between the windings of adjacent coils, thereby obtaining coils 101A, 101B that have the required dielectric strength. Furthermore, because of the double insulation structure described above, the thickness of the first insulating layer 50 does not need to be set as thick as that of conventional insulating layers. In addition, because not only the second insulating layer 70 but also the first insulating layer 50 is already interposed between the windings of adjacent coils, the thickness of the second insulating layer 70 does not need to be set as thick as that of conventional insulating layers. Therefore, the cross-sectional area of ​​the insulating layers (first insulating layer 50, second insulating layer 70) can be reduced. This allows the proportion of the cross-sectional area of ​​the conductor portion (substrate bundle 30) to be relatively increased, resulting in coils 101A, 101B with a higher space factor than conventional coils. As described above, according to the method for manufacturing a coil according to the first embodiment, a coil having a high space factor while ensuring the necessary dielectric strength voltage can be obtained.

[0062] (6) Furthermore, the first insulating layer forming process of embodiment 1 is configured to include, in this order, an infiltration step of infiltrating a water-soluble material into the substrate bundle 30, and a solidification step of solidifying the infiltrated water-soluble material. Therefore, due to the effect of penetration, the water-soluble material can reach even between the substrates inside the substrate bundle 30 and fill the gaps between the substrates, so that the dripping, uneven adhesion, etc. described in (3) above do not occur, and a uniform first insulating layer 50 can be obtained regardless of the part of the coil. As a result, a high-quality coil can be obtained that has uniform dielectric strength characteristics regardless of the part of the coil and stable insulating characteristics. Furthermore, forming the first insulating layer using a water-soluble material requires fewer steps than forming the first insulating layer by coating, because the material that will become the first insulating layer can be spread all over the substrate 10 simply by immersing the substrate bundle 30 in an aqueous solution containing the water-soluble material. Therefore, the coil manufacturing method according to the first embodiment not only produces high-quality coils, but also improves work efficiency and enables coil manufacturing with excellent mass productivity.

[0063] Furthermore, by performing the step of permeating and solidifying the water-soluble material described above using electrodeposition insulating coating, the film thickness of the first insulating layer 50 can be easily controlled. That is, the film thickness of the first insulating layer 50 can be easily controlled by adjusting the DC voltage applied between the substrate bundle 30, which is the object to be coated, and the electrode. Furthermore, by controlling the applied DC voltage, it is possible to easily reduce variations in the film thickness of the first insulating layer 50 compared to coating. Furthermore, even when manufacturing a coil with a complex three-dimensional shape (with uneven shapes), electrodeposition insulating coating makes it easy to form an insulating film (first insulating layer 50) on the coil surface. For these reasons, by using electrodeposition insulating coating for the step of permeating and solidifying the water-soluble material, it is possible to obtain high-quality coils that are suitable for mass production, have optimal specifications (film thickness), and have uniform and stable dielectric strength characteristics.

[0064] [Embodiment 2] Fig. 5 is a diagram for explaining a coil 102A according to embodiment 2. Fig. 5(a) and Fig. 5(b) are drawings corresponding to Fig. 2(a) and Fig. 2(b). In embodiment 2, for components that have the same basic configurations and features as embodiment 1, the same reference numerals as embodiment 1 are used or the reference numerals are not used, and descriptions of those components are omitted.

[0065] 1. Coil 102A according to the second embodiment The coil 102A according to the second embodiment basically has the same configuration as the coil 101A according to the first embodiment, but differs from the coil 101 according to the first embodiment in the relationship between the substrate 10 and the first insulating layer 50. That is, as shown in Fig. 5(b), in the coil 102A according to the second embodiment, a first insulating layer 50 is formed integrally with each of the substrates 10 in advance. Specifically, when forming the substrate bundle 30, so-called "magnet wire (no symbol)" in which an insulating coating is applied to the substrates 10 in advance is used. "Magnet wire" is a substrate made of copper wire or the like in which an insulating coating such as enamel is applied in advance. In the coil 102A according to the second embodiment, such a magnet wire is used as a starting point, and a stranded wire 20 made by twisting six magnet wires together is constructed as an intermediate material, and three sets of such stranded wires 20 are braided to form the braided wire 24. In that the braided wire 24 is further constructed by forming the stranded wire 20, this is the same as the coil 101A according to the first embodiment. The remaining second insulating layer 70 can also be configured in the same manner as the second insulating layer 70 of the first embodiment.

[0066] 2. Coil 102 according to the second embodiment A Manufacturing method 6 is a manufacturing process diagram illustrating a manufacturing method of the coil 102A according to embodiment 2. For components having the same basic configurations and features as those in embodiment 1, the same reference numerals as those in embodiment 1 are used or the reference numerals are omitted, and the description of those components is omitted.

[0067] The method for manufacturing the coil 102A according to the second embodiment includes the following steps (a) to (d) in this order. (a) a coated wire preparation process for preparing a coated wire (magnet wire: no symbol) on which an insulating coating, which is the first insulating layer 50, has been formed around the substrate 10; (b) a substrate bundle preparation process for bundling multiple coated wires to prepare a substrate bundle 30 (see (i) to (ii) in Figure 6). Note that "bundling" here includes twisting and braiding. Figure 6(i) shows a state in which six coated wires (magnet wires) are twisted to form a stranded wire 20. Figure 6(ii) shows a state in which three sets of stranded wires 20 are braided to form a braided wire 24. This braided wire 24 constitutes a substrate bundle 30.

[0068] (c) a substrate bundle forming process in which the substrate bundle 30 is wound around the air-core region 90 to form the substrate bundle 30 (see (iii) of Figure 6 and Figure 1(b)); (d) a second insulating layer forming process in which a second insulating layer 70 made of an insulating material is formed around the winding group 62 so as to surround the "winding group 62" consisting of the windings 42a, 42b formed by the substrate bundle 30 and the first insulating layer 50 (see (vi) of Figure 6).

[0069] 3. Effects of the coil 102A and coil manufacturing method according to the second embodiment According to the coil 102A of embodiment 2, a coated wire (magnet wire) with an insulating coating applied to the substrate 10 is used, resulting in a coil 102A with a standardized first insulating layer 50, and a high-quality coil with stable insulating properties. Furthermore, according to the manufacturing method of the coil 102A of the second embodiment, a coated wire (magnet wire) in which an insulating coating is applied in advance to the substrate 10 is used, so that a high-quality coil with stable insulating properties having a standardized first insulating layer 50 can be obtained, and the first insulating layer forming process of the first embodiment can be omitted, realizing coil manufacturing with high work efficiency and excellent mass productivity.

[0070] The coil 102A and the coil manufacturing method according to the second embodiment have basically the same configuration as the coil 101A and the coil manufacturing method according to the first embodiment, except for the relationship between the substrate 10 and the first insulating layer 50. Therefore, the coil 102A and the coil manufacturing method according to the second embodiment similarly exhibit the corresponding effects of the coil 101A and the coil manufacturing method according to the first embodiment.

[0071] [Experimental Example] The inventors have conducted experiments on the generation of eddy currents that accompany the movement of magnets in electromechanical devices, and have gained new knowledge about coils that suppress the generation of eddy currents, which will be described below.

[0072] 1. Experimental Setup FIG. 7 is a schematic diagram showing the experimental setup in the experimental example. In order to reproduce the movement of a magnet in an electromechanical device, a pendulum-shaped experimental jig was constructed as shown in Fig. 7. Specifically, permanent magnets MGa and MGb were disposed on one end 710b of a rod 710 via a fixing member 720 (reference numeral 730 indicates the pair of permanent magnets MGa and MGb), and the other end 710a of the rod 710 was fixed to a rotation axis AX2. The other end 710a of the rod 710 was connected to a bearing shaft so that it could rotate with a low coefficient of friction. In addition, a sample (referred to as Sample in the figure) was placed directly below the rotation axis AX2. The sample was fixed on the top surface of a sample fixing stage 740 made of a non-magnetic material, and a gap G was set between the level of the top surface of the sample and the permanent magnet pair 730 disposed at the tip of the pendulum, so that the sample and the permanent magnet pair 730 did not come into spatial contact with each other.

[0073] 2. Samples and Experimental Methods (1) Sample The samples were basically assumed to be coils, but more specifically, various conductive material candidates such as the substrate 10 and substrate bundle 30 were assumed, and these samples were used in the experiment. Specifically, the materials shown in the second column of the table in Fig. 8 (described later) were shaped into rectangular shapes of 30 mm x 10 mm in plan view, and each was prepared as a sample.

[0074] (2) Experimental method First, a sample corresponding to the experiment number is placed on the sample fixing stage 740. At that time, the position of the sample fixing stage 740 is adjusted so that the gap G is approximately 1 mm regardless of the experiment number. Next, the permanent magnet pair 730 is raised to the position shown by the solid line in FIG. 7 so that the height of the center of the permanent magnet pair 730 coincides with the height of the rotation axis AX2 (ie, so that the rod 710 is horizontal). The pendulum is then released. As a result, the permanent magnet pair 730 begins to move in the direction of arrow C0 in Figure 7, vibrating back and forth, alternately moving in the directions of arrows C1 and C2 directly above the sample. This vibration dampens and eventually stops due to resistance between the pendulum and the air, as well as losses caused by eddy currents generated when the permanent magnet pair 730 passes near the sample. Experimental data is obtained by observing this vibration. The observations are the number of times the pendulum vibrates (the number of times it takes for the pendulum to stop, hereinafter simply referred to as the number of vibrations) and the duration of vibration (the time required for the pendulum to stop, hereinafter simply referred to as the vibration duration). Under the assumption that the greater the number of vibrations and / or the vibration duration, the less loss due to eddy currents will be generated. Note that although the samples in Experiments 6 and 7 were not conductor wires, they were observed for comparison. Experiments 1 to 7 were conducted using the above experimental method.

[0075] 3. Experimental Results FIG. 8 is a table showing the experimental results of the experimental example. As shown in Figure 8, for Experiments 2, 4, and 5, in which the average radius of the substrate (conductor portion) was 100 μm or less, the number of reciprocating motions and vibration time were relatively large, and the generation of eddy currents was small. Furthermore, when the average radius of the substrate (conductor portion) was 50 μm or less, the generation of eddy currents was even smaller. Furthermore, for Experiments 4 and 5, which were braided wires in which multiple bare conductor wires were braided, the number of reciprocating motions and vibration time were relatively large, and the generation of eddy currents was small. Furthermore, for the magnet wire of Experiment 2 (in which an insulating coating was previously applied to the conductive portion as the substrate), the number of reciprocating motions and vibration time were relatively large, and the generation of eddy currents was small. Furthermore, for the plated copper wire of Experiment 3, the number of reciprocating motions and vibration time were relatively large, and the generation of eddy currents was small.

[0076] 4. Discussion (1) From the above experimental results, it became clear that in constructing the coil of the present invention, it is preferable that the average radius of the substrate 10 is 100 μm or less (Experiment Nos. 2, 4, and 5). (2) When constructing the coil of the present invention, under the conditions of (1) above, it was found that it is more preferable for the substrate bundle 30 to be made of a braided wire 24 in which multiple bare conductor wires 12 are braided (Experiment Nos. 4 and 5). (3) When constructing the coil of the present invention, under the conditions of (1) above, it was found that it is more preferable for the substrate bundle 30 to be made of "magnet wire" in which an insulating coating has been applied to the substrate 10 in advance (Experiment No. 2). (4) It was also found that the substrate 10 can be suitably a nickel-plated wire in which a copper wire is plated with nickel or a tin-plated wire in which a copper wire is plated with tin (Experiment No. 3). It has been confirmed that the generation of eddy currents can be reduced by employing a substrate 10 and a substrate bundle 30 that satisfy any one or a combination of the above (1) to (4).

[0077] [Variations] Although the present invention has been described above based on the above embodiment, the present invention is not limited to the above embodiment and can be embodied in various forms without departing from the spirit of the present invention, and for example, the following modifications are also possible.

[0078] (1) The number, material, shape, position, size, etc. of the components described in the above embodiment are examples and can be changed within the scope that does not impair the effects of the present invention.

[0079] (2) The number of turns of the windings can also be changed. Fig. 9 is a diagram shown to explain a coil 103A according to Modification 1. Reference numeral 63 denotes a winding group. Figs. 9(a) and 9(b) are drawings corresponding to Figs. 2(a) and 2(b). In the drawings, for components that have the same basic configuration and features as those of Embodiment 1, the same reference numerals as those of Embodiment 1 are used or the reference numerals are not assigned, and descriptions of those components are omitted.

[0080] In the description of the first embodiment, a coil 101 of a type in which the windings 41a and 41b are wound approximately 1.75 turns around the air-core region 90 and the windings are stacked in two layers has been exemplified. However, the present invention is not limited to this. For example, as shown in Fig. 9, the coil 103A may be configured with a single layer of winding 43 in which the winding 43 is wound approximately 0.75 turns around the air-core region 90 (Modification 1).

[0081] (3) Figure 10 is a diagram for explaining a coil 104A according to Modification 2. Figures 10(a) and 10(b) are drawings corresponding to Figures 5(a) and 5(b). Reference numeral 64 denotes a winding group. In the diagram, for components that have the same basic configuration and features as those of Embodiment 2, the same reference numerals as those of Embodiment 2 are used or the use of reference numerals is omitted, and description of those components is omitted.

[0082] In the description of the second embodiment, a coil 102A has been illustrated in which the windings 42a and 42b are wound approximately 1.75 times around the air-core region 90, and the windings are stacked in two layers. However, the present invention is not limited to this. For example, as shown in FIG. 10 , a coil 104A may be configured with a single layer of winding 44, in which the winding 44 is wound approximately 0.75 times around the air-core region 90 (Modification 2).

[0083] (4) In the first embodiment, the second embodiment, the first modification, and the second modification have been described assuming that the first insulating layer 50 and the second insulating layer 70 are formed of separate members (or formed in separate processes in the case of a manufacturing method invention). However, the present invention is not limited to this. Specifically, the first insulating layer 50 and the second insulating layer 70 may be formed of the same member (or formed in the same process in the case of a manufacturing method invention). For example, the first insulating layer 50 and the second insulating layer 70 may both be formed as electrodeposited insulating coatings formed around the substrate 10 made of bare conductor wires 12. In the case of a manufacturing method invention, the first insulating layer 50 and the second insulating layer 70 may be formed by a single electrodeposited insulating coating.

[0084] (5) In each embodiment, an electromechanical device that operates by being excited in two phases has been described as an example. However, the present invention is not limited to this and can also be applied to an electromechanical device that operates by being excited in three phases, for example.

[0085] (6) In each embodiment, the present invention is described with reference to a coreless motor as an example of its application. However, the present invention is not limited to this and can be applied to general electromechanical devices such as coreless generators, regenerative brakes, and actuators. [Explanation of symbols]

[0086] 10,910...Base material, 12,912...Bare conductor wire, 20...Twisted wire, 24,924,924'...Braided wire, 30...Base material bundle, 41a, 41b, 42a, 42b, 43, 44,940,940'...Winding, 50...First insulating layer, 61, 62, 63, 64...Winding group, 70...Second insulating layer, 81A, 81B...First coil end portion, 82A, 82B...Second coil end portion, 84A, 84B...Active coil portion, 85A, 85B, 86A, 86B...Coil end, 90A, 90B, 99 0...air core region, 100...coil assembly, 101A, 101B, 102A, 103A, 104A, 901, 902...coil, 101AS...first coil subassembly, 101BS...second coil subassembly, 710...rod, 710a...other end side (of rod), 710b...one end side (of rod), 720...fixing member, 730...permanent magnet pair, 740...sample fixing stage, 914a...magnet wire, 950...insulating coating, 950'...insulating coating layer

Claims

1. An air-core coil arranged along the moving direction of a magnet of an electromechanical device, a substrate made of a conductive material; a first insulating layer made of an insulating material and formed around a substrate bundle obtained by bundling a plurality of the substrates so as to be in contact with the substrate when the coil is cut along an imaginary plane perpendicular to the longitudinal direction of the substrate and the cut surface is viewed; a second insulating layer formed around a "winding group" formed by winding the winding around an air-core region when the "winding" formed by the substrate bundle and the first insulating layer formed around the substrate bundle is cut along an imaginary plane perpendicular to the longitudinal direction of the winding and the cut surface of the winding is viewed; and A coil equipped with

2. 2. The coil according to claim 1, The coil is characterized in that the second insulating layer is an insulating layer formed by hardening a material that has insulating properties and adhesive properties.

3. The coil according to claim 1 or 2, A coil characterized in that the first insulating layer is an insulating layer formed by solidifying a water-soluble material that has permeated the periphery of the substrate, which is made of a bare conductor wire.

4. The coil according to claim 3, The coil is characterized in that the first insulating layer is an electrodeposited insulating coating formed around the substrate made of the bare conductor wire.

5. The coil according to claim 1 or 2, The coil is characterized in that the first insulating layer is an insulating coating film formed around the substrate made of a bare conductor wire.

6. The coil according to any one of claims 1 to 5, A coil characterized in that the average radius of the substrate is 100 μm or less.

7. 7. The coil according to claim 6, A coil characterized in that the substrate bundle is made of a braided wire in which a plurality of bare conductor wires are braided.

8. 7. The coil according to claim 6, The coil is characterized in that the substrate bundle is made of "magnet wire" in which an insulating coating is applied to the substrate in advance.

9. The coil according to any one of claims 1 to 5, A coil characterized in that the substrate is a nickel-plated wire in which a copper wire is nickel-plated or a tin-plated wire in which a copper wire is tin-plated.

10. A method for manufacturing the coil according to claim 1 or 2, comprising the steps of: a substrate bundle preparation step of bundling a plurality of bare conductor wires as the substrate to prepare the substrate bundle; a substrate bundle forming step of winding the substrate bundle around the air-core region to form the substrate bundle; a first insulating layer forming step of forming the first insulating layer made of an insulating material around the periphery of the formed substrate bundle so as to be in contact with the substrate; a second insulating layer forming step of forming the second insulating layer made of an insulating material around the "winding group" formed by the windings constituted by the base bundle and the first insulating layer so as to surround the winding group; A method for manufacturing a coil, comprising the steps of:

11. The method for manufacturing a coil according to claim 10, The first insulating layer forming step includes: an infiltration step of infiltrating the substrate bundle with a water-soluble material; a solidification step of solidifying the permeated water-soluble material; A method for manufacturing a coil, characterized by having the above steps in this order.

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