Coils and methods for manufacturing coils

Abstract

To provide a coil having a high space factor while necessary withstand voltage is ensured.SOLUTION: Air-core coils 101A are arranged along the movement direction of a magnet in an electric machine device. Each coil includes base materials 10, a first insulation layer 50 that is formed so as to be in contact, in a cross section, with the base materials 10 and disposed around a base material bundle 30 formed of a bundle of a plurality of the base materials 10, and a second insulation layer 70 that is formed around a winding wire group 61 formed by winding wires 41a, 41b wound around an air-core region 90A, so as to surround the winding wire group 61.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a coil for a coreless electric machine device and a method for manufacturing the coil.

Background Art

[0002] Coils used in coreless electric machine devices are known.

[0003] FIG. 11 is a diagram showing conventional coils 901 and 902. FIG. 11(a) is a diagram schematically depicting a coil group formed by sequentially connecting a plurality of coils 901 and 902. Here, an example is shown where only the coil group related to the A phase when the coreless electric machine device is a two-phase coreless motor is taken out. Each of the coils 901 and 902 has windings 940 and 940' wound around a hollow core region 990. Here, it is assumed that the windings 940 and 940' are wound approximately twice, and the first-turn winding and the second-turn winding are laminated in two layers. Reference sign PL1 indicates a virtual plane perpendicular to the length direction of the windings 940 and 940'.

[0004] FIG. 11(b) is a cross-sectional view of the conventional coil 901 when the conventional coil 901 is cut along the virtual plane PL1 shown in FIG. 11(a) and the cut surface is viewed along arrow A. As shown in FIG. 11(b), in the conventional coil 901, magnet wires 914a each having an insulating film 950 applied to each of the base materials 910 made of conductive members are used. In the example of the figure, a plurality of magnet wires 914a are twisted, and a braided wire 924 in which a plurality of twisted units are braided is used as the winding 940 (the conventional first winding 940).

[0005] Figure 11(c) is a cross-sectional view of another conventional coil 902 when it is cut along the virtual plane PL1 shown in Figure 11(a), and the cut surface is viewed along arrow A. As shown in Figure 11(c), the other conventional coil 902 uses a braided wire 924' in which bare copper wires 912 made of conductive material are bundled, twisted, and braided together. Then, a winding 940' (conventional second winding 940') is formed by forming an insulating coating layer 950' around this braided wire 924'. Furthermore, a similar second winding 940' to the conventional type is also described in Patent Document 1 (Figure 11) and Patent Document 2 (Figure 7). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2018 / 139245 [Patent Document 2] International Publication No. 2018 / 139246 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Incidentally, if we assume that the electromechanical device is, for example, a motor, the coils mentioned above are each positioned at the poles of the stator. When adjacent coils are placed close together, the windings belonging to each adjacent coil will also be close to each other. Therefore, it is necessary to ensure a high dielectric strength (hereinafter sometimes simply referred to as "insulation withstand voltage") between these windings. For these reasons, in order to ensure dielectric strength, the thickness of the insulating coating 950 in the conventional first winding 940 is set to be relatively large. Consequently, in the first winding 940, which is made up of many substrates 910 coated with the insulating coating 950, the proportion of the cross-sectional area occupied by the insulating coating 950 (insulating layer) is large. Conversely, the proportion of the cross-sectional area of ​​the conductor part is relatively small, resulting in a low "fill factor" (see Figure 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 dielectric strength, resulting in a low fill factor (see Figure 11(c)). In other words, conventional coils 901 and 902 sacrifice the packing factor in exchange for ensuring the required dielectric strength.

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

[0009] According to one aspect of the present invention, an air-core coil is provided which is arranged along the direction of movement of a magnet in an electromechanical device. The coil comprises a base material made of a conductive material, a first insulating layer made of an insulating material formed around a bundle of base materials, such that it is in contact with the base material when the coil is cut by a virtual plane perpendicular to the longitudinal direction of the base material and the cut surface is viewed, and a second insulating layer made of an insulating material formed around a group of windings, such that when the windings, which are composed of the bundle of base materials and the first insulating layer formed around the bundle of base materials, are cut by a virtual plane perpendicular to the longitudinal direction of the windings and the cut surface is viewed, the windings form a group of windings that wind around an air-core region.

[0010] Furthermore, according to another aspect of the present invention, a method is provided for manufacturing air-core coils arranged along the direction of movement of magnets in an electromechanical device. The method for manufacturing such a coil includes, in this order: a base material bundle preparation step of bundling a plurality of bare conductor wires as the base material to prepare the base material bundle; a base material bundle forming step of winding the base material bundle around the air core region to form the base material bundle; a first insulating layer forming step of forming the first insulating layer made of an insulating material around the formed base material bundle so as to be in contact with the base material; and a second insulating layer forming step of forming the second insulating layer made of an insulating material around the winding group so as to surround the winding group formed by the base material bundle and the first insulating layer.

[0011] In the above-described method for manufacturing a coil, the first insulating layer formation step preferably comprises, in this order, a penetration step of impregnating the substrate bundle with a water-soluble material, and a solidification step of solidifying the impregnated water-soluble material. [Effects of the Invention]

[0012] The coil of the present invention achieves a high packing factor while ensuring the required dielectric strength. Furthermore, the coil manufacturing method of the present invention makes it possible to manufacture a coil with a high packing factor while ensuring the required dielectric strength. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view illustrating the coils 101A and 101B (sometimes referred to as the first-shaped coil 101A and the second-shaped coil 101B) and the first coil sub-assembly 101AS, second coil sub-assembly 101BS, and coil assembly 100, which are each composed of the coils 101A and 101B according to Embodiment 1. [Figure 2] This is a diagram illustrating the coil 101A according to Embodiment 1. [Figure 3] This is a manufacturing process diagram illustrating the manufacturing method of coil 101A according to Embodiment 1. [Figure 4] This figure is shown to illustrate the effects of coils 101A and 101B according to Embodiment 1. [Figure 5] This is a diagram showing the coil 102A according to Embodiment 2. [Figure 6] This is a manufacturing process diagram showing the manufacturing method of the coil 102A according to Embodiment 2. [Figure 7] This is a schematic diagram showing the experimental configuration in the experimental example. [Figure 8] This is a table showing the experimental results in the experimental example. [Figure 9] This is a diagram showing the coil 103A according to Modification 1. [Figure 10] This is a diagram showing the coil 104A according to Modification 2. [Figure 11] This is a diagram showing the conventional coils 901 and 902.

Mode for Carrying Out the Invention

[0014] Hereinafter, embodiments of the coil and the manufacturing method of the 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 actual dimensions, ratios, etc.

[0015] [Embodiment 1] 1. Configuration of the coils 101A and 101B according to Embodiment 1 (1) Overview of the coils 101A, 101B and the coil assembly 100 The coils 101A and 101B according to Embodiment 1 are air-core coils arranged along the moving direction of the magnet of the electromechanical device. The electromechanical device to which the coils 101A and 101B are applied may be any device that uses an air-core coil. A so-called coreless motor is one of the suitable application targets. Figure 1(a) is a perspective view showing an example of a coil assembly 100 used in a coreless motor. Here, multiple coils 101A and 101B (subscript numbers are index numbers) are arranged along the direction of movement ROT of the permanent magnets (not shown) of the rotor to constitute the coil assembly 100. In other words, the coil assembly 100 is constructed by arranging multiple coils 101A and 101B such that the effective coil portion of each coil 101A and 101B (reference numeral 84A in Figure 1(d) and reference numeral 84B in Figure 1(e)) is perpendicular to the direction of movement ROT of the magnets. In Figure 1(a), the direction parallel to the rotation axis AX1 of the coreless motor is defined as the y-direction, the direction perpendicular to the rotation axis is defined as the x-direction, and the direction perpendicular to both the x-direction and the y-direction is defined as the z-direction. The coils 101A and 101B, which are arranged according to these directional definitions, also use the same directional definitions as the definitions of the directional relationships (x-direction, y-direction, z-direction).

[0016] Figure 1(d) is a perspective view showing the external appearance of coil 101A (first shape coil). As shown in the figure, coil 101A is an air-core coil. Figure 1(d) mainly shows the external shape of coil 101A and does not explicitly show its internal structure. However, tracing from the coil end 85A side, coil 101A is formed in the following order: effective coil section 84A (lower section), first coil end section 81A (lower section), effective coil section 84A (lower section), second coil end section 82A, effective coil section 84A (upper section), first coil end section 81A (upper section), and effective coil section 84A (upper section), leading to the coil end 86A. In this way, coil 101A is constructed by forming windings 41a and 41b (see Figure 2, described later) so as to wind around the air core region 90A approximately twice (more precisely, approximately 1.75 times). Note that coil 101A as a first-shape coil has a stepped shape in which the first coil end section 81A is offset radially inward from the effective coil section 84A (towards the rotation axis AX1 when the coils are arranged). An "air-core coil" can also be defined as a coil made by winding a conductive material, in which no salient pole iron core is placed inside the winding. Here, "winding" includes not only cases where the coil is wound to completely surround the air-core region over 360°, but also winding methods that surround the air-core region but do not go all the way around it (not 360°).

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

[0018] Figure 1(b) is a perspective view of the first coil subassembly 101AS. The first coil subassembly 101AS can be constructed by arranging N coils 101A (first-shaped coils) in a ring shape with the outer surfaces of the effective coil portions 84A of adjacent coils 101A (first-shaped coils) touching each other, and then bonding them together. Figure 1(c) is a perspective view of the second coil subassembly 101BS. The second coil subassembly 101BS can be constructed by arranging N (in this case, 8) coils 101B (second-shaped coils) in a ring shape with the outer surfaces of the effective coil portions 84B of adjacent coils 101B (second-shaped coils) in contact with each other, and then bonding them together.

[0019] As described above, the first coil sub-assembly 101AS and the second coil sub-assembly 101BS are prepared, and the coil assembly 100 (see Figure 1(a)) can be constructed by sliding the second coil sub-assembly 101BS (Figure 1(c)) from the right side to the left side of the first coil sub-assembly 101AS (Figure 1(b)).

[0020] (2) Cross-section of coil 101A In the following descriptions (Embodiment 1, Embodiment 2, Modification 1, and Modification 2), we will use coil 101A, which is the first type of coil, as a representative example to explain its cross-sectional structure and other features, among the two types of coils 101A and 101B, which have different shapes. Furthermore, the embodiments described below are also applicable to coil 101B, which is a second-shaped coil, and are also 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 Figure 2(a) is a plan view of coil 101A as seen along the -z direction, and the right side of Figure 2 is a right side view of coil 101A as seen along the -x direction. In the figures, a pattern similar to braided wire is depicted on the surface, but in reality, no braided wire is exposed. The pattern in the figures is a depiction of the pattern of the second insulating layer 70, which is formed to resemble the pattern of braided wire. Figure 2(b) is a cross-sectional view of the main part of coil 101A cut along the BB cutting line in the left side of Figure 2(a). That is, Figure 2(b) is also a view of the cut surface when coil 101A is cut along a virtual plane perpendicular to the length direction of the base material 10 (described later) (corresponding to the virtual plane PL1 in Figure 1(d)). Note that in Figure 2(a), for the sake of explanation, the structure is depicted as having no stepped shape on the side of the first coil end portion 81A (not shown). The same applies to Figures 5(a), 9(a), and 10(a) thereafter.

[0022] As shown in Figure 2(b), the coil 101A comprises a base material 10, a first insulating layer 50, and a second insulating layer 70 as its basic components.

[0023] (3) Configuration of the conductor part based on the base material 10 The base material 10 is a component made of conductive material. Any conductive material may be used for the base material 10. In Embodiment 1, for example, a "copper wire" made mainly of copper, a "carbon wire" made of carbon, or a "plated wire" which is a copper wire or the like that has been nickel-plated or tin-plated can be used.

[0024] Furthermore, the thickness of the substrate 10 can be selected appropriately according to the specifications of the electromechanical device. In Embodiment 1, it is preferable that the average radius of the substrate 10 is 100 μm or less. It is even more preferable that the average radius of the substrate 10 is 50 μm or less. Details will be described in the [Experimental Examples] chapter, but by using a substrate 10 with such a diameter, the generation of eddy currents can be reduced.

[0025] In the example shown in Figure 2(b), bare conductor wires 12 (for example, bare copper wires) are used as the base material 10, and stranded wires 20, which are made by twisting six strands of the bare conductor wires 12 together, are used as the intermediate material. Three sets of these stranded wires 20 are then braided together to form a braided wire 24. The unit of the braided wire 24 here is the unit of the "conductor portion" of the winding 41, and also the unit of the "base material bundle 30".

[0026] "Base material bundle 30" refers to a unit formed by bundling multiple base materials 10. The term "bundling" in the context of a base material bundle includes both a direct bundling of multiple bare base materials (bare copper wires or other bare conductor wires) (Embodiment 1) and an indirect bundling of base materials that have a pre-formed first insulating layer (Embodiment 2) for primary insulation. Here, "bare conductor wire," "bare copper wire," etc., refers to a wire in which no insulating material is coated around it, leaving the conductive component (conductor) exposed. Examples include bare copper wire, nickel-plated wire, tin-plated wire, and carbon wire.

[0027] Furthermore, in Embodiment 1, for example, a bundle of multiple base materials 10 tied together in a straight line can be used as the "base material bundle 30." However, considering that bending stress will be applied when the base materials 10 are later formed into a winding, it is preferable to use a bundle of base materials 10 that are twisted or bent (e.g., Litz wire), braided (braided wire), etc., as the "base material bundle 30."

[0028] Furthermore, in Embodiment 1, it is preferable that the base material bundle 30 is made of a braided wire 24 in which a plurality of bare conductor wires 12 (base material 10) are braided together. As will be described in detail in the [Experimental Examples] chapter, this is because the generation of eddy currents can be reduced by adopting a base material bundle 30 with such a configuration.

[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 base material 10 when the coil 101 is cut by a virtual plane perpendicular to the longitudinal direction of the base material 10 and the cut surface is viewed. The first insulating layer 50 is also formed around a base material bundle 30 which is made up of multiple base materials 10 bundled together (see Figure 2(b)). The first insulating layer 50 may be slightly interposed between the bare conductor wires 12 that make up the braided wire 24. Alternatively, the bare conductor wires 12 that make up the braided wire 24 may be in contact with each other. Here, "when the coil is cut by a virtual plane perpendicular to the longitudinal direction of the base material 10" can be rephrased as "when the coil is cut by a virtual plane perpendicular to the longitudinal direction of the windings 41a and 41b," which will be described later. The reverse is also possible. As mentioned above, the base material 10 may be twisted or braided, so at a microscopic level, the longitudinal direction of the base material 10 does not necessarily coincide with the longitudinal direction of the windings 41. However, when the base material 10 is cut along the longitudinal direction of the windings 41, the cross-sectional area of ​​the base material 10 is often smallest. Therefore, "when the coil is cut by a virtual plane perpendicular to the longitudinal direction of the windings 41" can be considered as "when the coil is cut by a virtual plane perpendicular to the longitudinal direction of the base material 10." Furthermore, in the effective coil section 84A, "when the coil is cut by a virtual plane perpendicular to the longitudinal direction of the base material 10" can also be rephrased as "when the coil is cut by a virtual plane perpendicular to the y-direction."

[0030] The first insulating layer 50 may be made of any insulating material. In Embodiment 1, the first insulating layer 50 is preferably an insulating layer formed by solidifying a water-soluble material that has penetrated around the base material 10, which is made of bare conductor wire 12. Furthermore, in this case, it is even more preferable that the first insulating layer 50 is an electrodeposited insulating coating film formed around the base material 10, which is made of bare conductor wire 12. In other words, the first insulating layer 50 here is an "electrodeposited insulating coating film" obtained by electrodepositing the base material 10 of bare conductor wire 12. The electrodeposited insulating coating film as the first insulating layer 50 coats the bare conductor wire 12 and is made of an insulating material and has an insulating function.

[0031] On the other hand, it is also preferable if the first insulating layer 50 is an insulating coating film formed around the base material 10, which is made of bare conductor wires 12. This is because the first insulating layer 50 can be constructed 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 wire 12 and is made of insulating material and has insulating function.

[0032] (5) Winding 41 and winding group 61 The "winding 41" is composed of a base material bundle 30 and a first insulating layer 50 formed around the base material bundle 30. For reference, the unit of this "winding 41" is the unit of the shape that is wound around the air core region 90A. In the example shown in the figure, as a result of the winding 41 being formed to wind around the air-core region 90, the windings are stacked in the effective coil section 84A such that winding 41a is in the upper position and winding 41b is in the lower position (with the +z direction being "up"). In the example shown in the figure, the "winding group 61" is composed of these windings 41a and 41b. However, the term "winding group" here refers to a group of windings that are not wound around the air-core region 90A multiple times, but are still included in the concept of a "winding group." For example, single-layer windings that are not stacked on top of each other, such as winding group 63 in [Modification 1] and winding group 64 in [Modification 2] described later, are also included in the concept of a "winding group" as used here.

[0033] (6) Second insulating layer 70 The second insulating layer 70 is made of insulating layer material. When the winding 41 is cut by a virtual plane PL1 perpendicular to the length direction of the winding 41 and the cut surface of the winding 41 is viewed (in other words, when the coil 101A is cut by a virtual plane PL1 perpendicular to the length direction of the base material 10 and the cut surface is viewed), the second insulating layer 70 is formed around the winding group 61, which is formed by the winding 41 winding around the air core region 90. In other words, the second insulating layer 70 is further formed around the bundle of windings 41 (winding group 61) when the windings 41 are bundled together. In Figure 2(b), a small portion of the second insulating layer 70 is depicted as being interposed between winding 41a and winding 41b. However, this is not the only possible arrangement. Only the first insulating layer 50 constituting each winding may be interposed between winding 41a and winding 41b, and the second insulating layer 70 may be barely present.

[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, it is not limited to this. The second insulating layer 70 is preferably an insulating layer formed from a material that has both insulating and adhesive properties. In other words, the second insulating layer 70 serves not only for insulating purposes but also, as is clear from the state of the winding group 61 in Figure 3(v) described later, to bond the windings 41a and 41b while fixing their formed shape.

[0035] In the first embodiment, it is preferable that the dielectric strength of the second insulating layer 70 is greater than that 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 such that the relationship (dielectric strength of the second insulating layer 70) > (dielectric strength of the first insulating layer 50) is satisfied. In other words, it is preferable that the second insulating layer 70 and the first insulating layer 50 are configured such that the first insulating layer 50 mainly provides insulation under conditions where the potential difference between 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 for specific configuration methods, for example, if 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 such that the thickness of the second insulating layer 70, when viewed in cross-section, is greater than the thickness of the first insulating layer 50. By setting the dielectric strength of the first insulating layer 50 and the second insulating layer 70 in this relationship, the dielectric strength ED2 required between adjacent coil windings can be mainly ensured by the second insulating layer, while the thickness of the first insulating layer can be reduced to the minimum necessary to secure the dielectric strength ED1 required between windings constituting the same coil. As a result, the packing factor can be further increased.

[0036] Another possible configuration method is to set the thickness of both insulating layers to approximately the same, and then select the materials for both insulating layers such that a material with relatively high dielectric strength (a material with low conductivity) is applied to the second insulating layer 70, and a material with relatively low dielectric strength is applied to the first insulating layer 50.

[0037] However, Embodiment 1 does not prevent the coil from being configured such that the relationship (withstand voltage of the second insulating layer 70) ≤ (withstand voltage of the first insulating layer 50) is satisfied, and such a configuration is also included in Embodiment 1.

[0038] 2. Manufacturing method of coil 101A according to Embodiment 1 Figure 3 is a manufacturing process diagram illustrating the manufacturing method of coil 101A according to Embodiment 1. Broadly speaking, the manufacturing method of coil 101A includes a base material bundle preparation step, a base material 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 base material bundle preparation process involves preparing a "base material bundle 30" by twisting, braiding, or bundling multiple bare conductor wires 12, which serve as the base material 10. Specifically, for example, a stranded wire 20 is created by twisting six bare conductor wires 12 together and used as an intermediate material (see Figure 3(i)). Then, three sets of these stranded wires 20 are braided together to create a braided wire 24 (see Figure 3(ii)). This braided wire 24 is then used to form the base material bundle 30.

[0040] (2) Substrate bundle forming process The base material bundle forming process is a process of forming a base material bundle 30 by winding the base material 10 around an air core region 90A (not shown in Figure 3). Specifically, for example, aiming for a shape like that shown in Figure 1(d), the base material bundle 30 (braided wire 24) is wound around the air core region 90A to shape the effective coil portion 84A, the first coil end portion 81A, the second coil end portion 82A, etc., and the base material bundle 30 is formed. The cross-section immediately after the base material bundle forming process will have a shape in which the base material bundle 30 is stacked in two layers (see Figure 3(iii)).

[0041] Furthermore, after the base material bundle forming is complete, the coil ends 85A and 86A (see Figure 1(d)) are pre-masked by applying a penetrating insulating coating material such as polyesterimide, polyamideimide, polyimide, enamel, urethane, or varnish. This prevents them from being affected by the insulating material used around the base material bundle in the first and second insulating layer formation processes described later. The masking can be selectively removed by heating in a soldering furnace after the second insulating layer formation process is carried out.

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

[0043] Although not shown in the diagram, the formation of the first insulating layer is preferably carried out in the following order: a penetration step in which a water-soluble material (in this case, preferably a solute having insulating properties) is permeated into the substrate 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 both insulating and adhesive properties.

[0044] For example, a thermosetting resin solution is filled into a liquid tank or container (hereinafter simply referred to as a liquid tank), and then the upper or lower base material bundle 30, separated by a jig or the like, is placed inside the liquid tank. This causes the water-soluble material to penetrate (infiltrate) between the multiple base materials 10 that make up the base material bundle 30. The base material bundle 30 is then removed from the liquid tank with the water-soluble material adhering to the base materials 10. The base material bundle 30 is then heated to solidify the material derived from the water-soluble material adhering to the base materials 10. The above manufacturing method may be adopted.

[0045] Furthermore, it is even more preferable to perform the penetration and solidification of water-soluble materials 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 bundle of base materials 30 (the object to be coated), separated by a jig or the like, is placed inside the liquid tank so as to be completely submerged. In this way, the water-soluble material penetrates (inserts) between the multiple base materials 10 that make up the base material bundle 30. In this state, a DC voltage is applied between the object to be coated and the electrode to control the thickness of the insulating film, causing an electrodeposited insulating coating film derived from the water-soluble material to deposit around the base material bundle 30 (microscopically speaking, the base materials 10 that make up the base material bundle 30). This forms a first insulating layer 50 made of an electrodeposited insulating coating film around the base material 10, which is made of bare conductor wires 12. The above manufacturing method may be adopted. Furthermore, when applying a DC voltage, ultrasonic waves may be applied to the aqueous solution in the liquid tank. Applying ultrasonic waves can remove bubbles and impurities from around the substrate 10, thereby improving insulation quality.

[0046] It should be noted that the formation of the first insulating layer 50 is not limited to the electrodeposition insulating coating described above. For example, although not shown in the figures, an insulating material may be applied around the base material 10, which is made of bare conductor wire 12, to form an insulating coating film, and this insulating coating film may be used as the first insulating layer 50. With this method of forming an insulating coating film by application, the first insulating layer 50 can be constructed at a lower cost compared to the case of electrodeposition insulating coating, and an economically advantageous coil can be obtained.

[0047] (4) Second insulating layer formation process The second insulating layer formation step is a step of forming a second insulating layer 70 made of an insulating material around the winding group 61, which is composed of windings 41a and 41b formed by the base material bundle 30 and the first insulating layer 50 (see Figure 3(v)). Specifically, first, the upper base material bundle 30 (winding 41a) after the formation of the first insulating layer and the lower base material bundle 30 (winding 41b) after the formation of the first insulating layer are stacked to eliminate the gap between them. Next, an insulating coating material such as varnish is applied around these winding groups 61 to form an insulating coating film. This allows the second insulating layer 70 to be formed. Furthermore, the second insulating layer formation step also serves to bond the windings 41a and 41b with the second insulating layer 70, and to fix the shape of the formed coil 101A. By performing the above steps, coil 101A can be obtained.

[0048] 3. Effects of the coil 101A and the method for manufacturing the coil according to Embodiment 1 Since the coil 101A and the method for manufacturing the coil 101A according to Embodiment 1 have the above-described configuration, the following effects can be achieved.

[0049] (1) Achieving both sufficient dielectric strength and improved space factor Figure 4(a) is a schematic diagram showing the wiring state of coils 101A and 101B according to Embodiment 1. The figure shows an example assuming a two-phase coreless motor that operates by being excited by two phases, A phase and B phase. Figure 4(b) is a cross-sectional view when the windings belonging to adjacent coils are cut along the virtual plane PL2 in Figure 4(a).

[0050] First, I will briefly explain the challenges regarding dielectric strength in two-phase coreless motors. Each coil of the coil assembly 100 shown in Figure 1(a) above can be connected in the manner shown in Figure 4(a), for example. In the example shown in Figure 4(a), N (N=8) coils 101A are electrically connected sequentially between coil terminals 151 and 152 to constitute phase A (the coil group of phase A). Similarly, N (N=8) coils 101B are electrically connected sequentially between coil terminals 153 and 154 to constitute phase B (the coil group of phase B). In this case, the coils belonging to phase A and the coils belonging to phase B are arranged adjacent to each other in their respective effective coil sections 84A and 84B.

[0051] For example, if the A-phase voltage Va is applied to the A-phase terminal, the potential difference applied to one coil 101A is simply calculated to be Va / N. Now, let's continue the explanation by focusing on the leftmost coil 101A1 in the A-phase coil group. 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 is Va / N lower than the potential of the conductor portion of winding 41a (base material bundle 30, base material 10) near arrow D1, and the potential difference within a single coil 101A1 is Va / N. Therefore, when viewed within a single coil 101A1, it is sufficient to ensure an isolation voltage ED1 corresponding to a voltage of at most Va / N between "windings that constitute the same coil". Note that, in order to consider inrush current, the setting value of isolation voltage ED1 is actually set to a value larger than Va / N. On the other hand, when considering adjacent coils, if excitation voltages are applied to adjacent coils in different phases, a potential difference equivalent to, for example, Va may occur between the conductor portions within the windings of the adjacent coils. Therefore, it is necessary to ensure an isolation voltage corresponding to at least Va between the windings of adjacent coils.

[0052] Therefore, in the conventional windings 940 and 940' shown in Figure 11, the thickness of the insulating layer (insulating film 950, insulating film layer 950') was strictly set to be large in order to ensure the relatively high dielectric strength required between adjacent coil windings. As a result, the packing factor of the conventional coils 901 and 902 was low.

[0053] On the other hand, in the coil 101 according to Embodiment 1 shown in Figures 1 to 4, the first insulating layer 50 is formed "around the base material bundle 30, which is made up of multiple base materials 10 bundled together, so as to be in contact with the base material 10." Therefore, the first insulating layer 50 can be reliably interposed between the conductor portions of multiple windings that constitute the same coil. For example, as shown in Figure 4(b), the first insulating layer 50 can be reliably interposed between the conductor portion (base material bundle 30, base material 10) of the upper winding 41a that constitutes the same coil 101A1 and the conductor portion (base material bundle 30, base material 10) of the lower winding 41b. Therefore, the first insulating layer 50 makes it possible to secure the necessary dielectric strength 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, which is formed by windings winding around an air core region. Therefore, when multiple coils 101A and 101B are arranged as shown in Figures 1(a) and 4(a), the second insulating layer 70 can be interposed between the windings of adjacent coils in addition to the first insulating layer 50. Therefore, the first insulating layer 50 and the second insulating layer 70 make it possible to secure a relatively high dielectric strength ED2 between adjacent coil windings. Furthermore, when viewed from the base material bundle 30, there is a double layer of insulation between it and the base material bundle 30 of the adjacent coil winding, consisting of a second insulating layer 70 in addition to the first insulating layer 50 (double insulation). Therefore, even if a reverse surge occurs in either the base material bundle 30 or the base material bundle 30 of the adjacent coil winding, dielectric breakdown will not occur between these base material bundles 30, resulting in extremely safe coils 101A and 101B.

[0055] Furthermore, considering the first insulating layer 50 of Embodiment 1, (i) conventional insulating layers had to ensure not only the dielectric strength ED1 required between windings constituting the same coil, but also the dielectric strength ED2 required between adjacent coil windings, which have relatively large values. However, the first insulating layer 50 of Embodiment 1 basically only needs to consider the dielectric strength ED1. (ii) Generally, the required dielectric strength ED1 is lower (smaller) than the dielectric strength ED2. Considering these factors, the thickness of the first insulating layer 50 of Embodiment 1 does not need to be set as thick as that of conventional insulating layers. 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 layer (insulating film 950, insulating film layer 950') in conventional coils 901 and 902. Furthermore, considering the thickness of the second insulating layer 70, as mentioned above, since the first insulating layer 50 is already interposed between the windings of adjacent coils as well as the second insulating layer 70, it is not necessary to set the thickness of the second insulating layer 70 to be 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 increasing the overall cross-sectional area of ​​the coil 101. In this way, the cross-sectional areas of the first insulating layer 50 and the second insulating layer 70 can be reduced, and the space factor, which is the ratio of the cross-sectional area of ​​the conductor portion (base material bundle 30) to the entire coil 101, can be increased compared to the conventional method.

[0056] Based on the above, the coil 101 according to Embodiment 1 is a coil that has a high packing factor while ensuring the necessary dielectric strength.

[0057] Furthermore, increasing the packing factor leads to more efficient securing of the conductive area, thus reducing the resistance of the coil. As a result, heat generation can be suppressed, contributing to improved energy efficiency of electromechanical devices. Furthermore, by forming a second insulating layer 70 on the outside of the first insulating layer 50 to create a double layer of insulation, even if there are variations in the insulating quality of the first insulating layer 50 (due to bubbles, impurities, etc.), the second insulating layer 70 positioned on the outside can contribute to maintaining and improving the overall insulating quality of the coil.

[0058] (2) The second insulating layer 70 in Embodiment 1 is preferably an insulating layer formed by curing a material that has both insulating and adhesive properties. This configuration results in a coil in which windings 41a and 41b are firmly integrated, and the formed shape is less likely to collapse.

[0059] (3) In Embodiment 1, it is preferable that the first insulating layer 50 is an insulating layer formed by solidifying a water-soluble material that has penetrated around the base material 10, which is made up of bare conductor wires 12. When the first insulating layer 50 is composed of an insulating coating film coated with an insulating coating material, it is susceptible to effects such as dripping during coating and uneven adhesion of the coating material to the substrate. On the other hand, by composing the first insulating layer 50 as an insulating layer formed by solidifying a water-soluble material that has penetrated around the substrate 10 of the bare conductor wire 12, the water-soluble material can reach even between the substrates inside the substrate bundle 30 due to the effect of penetration, filling the gaps between the substrates. This prevents the aforementioned dripping and uneven adhesion, resulting in a homogeneous insulating layer regardless of the part of the coil. As a result, homogeneous dielectric strength characteristics can be obtained regardless of the part of the coil, resulting in a high-quality coil with stable insulating properties.

[0060] (4) In Embodiment 1, the first insulating layer 50 is an insulating layer formed by solidifying a water-soluble material that has penetrated around the base material 10 made of bare conductor wires 12, and it is even more preferable that the first insulating layer 50 is an electrodeposited insulating coating film formed around the base material 10 made of bare conductor wires 12. Electrodeposition coatings are generally formed by completely immersing the object to be coated (in this case, a bundle of substrates 30) in an electrodeposition coating solution and applying a predetermined voltage. The electrodeposition coating solution penetrates to reach both the outside and inside of the bundle of substrates 30, and the voltage is applied similarly not only to the substrates 10 located on the outside of the bundle of substrates 30 but also to the substrates 10 located on the inside. As a result, a homogeneous first insulating layer 50 is formed from the outside to the inside of the bundle of substrates 30. Therefore, the first insulating layer 50 is formed not only on the outside of the bundle of substrates 30 but also in the gaps of the substrates 10 on the inside, resulting in more homogeneous dielectric strength characteristics regardless of the coil location, and a high-quality coil with stable insulating properties.

[0061] (5) The method for manufacturing a coil according to Embodiment 1, as described above, includes in this order a base material bundle preparation step, a base material bundle forming step, a first insulating layer forming step in which a first insulating layer 50 made of an insulating material is formed around the base material 10 in contact with the base material 10, and a second insulating layer forming step in which a second insulating layer 70 made of an insulating material is formed around the winding group 61 so as to surround the winding group 61. This ensures that the first insulating layer 50 is reliably interposed between the conductor portions of multiple windings constituting the same coil, and that a second insulating layer 70 is also interposed between the windings of adjacent coils in addition to the first insulating layer 50, thereby obtaining coils 101A and 101B with the required dielectric strength. Furthermore, because of the double insulating structure described above, the thickness of the first insulating layer 50 does not need to be set as thick as that of a conventional insulating layer. In addition, since both the first insulating layer 50 and the second insulating layer 70 are 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 a conventional insulating layer. Therefore, the cross-sectional area of ​​the insulating layers (first insulating layer 50, second insulating layer 70) can be reduced. As a result, the ratio of the cross-sectional area of ​​the conductor portion (base material bundle 30) can be increased relatively, and coils 101A and 101B with a higher packing factor than conventional coils can be obtained. As described above, the method for manufacturing a coil according to Embodiment 1 makes it possible to obtain a coil with a high packing factor while ensuring the required dielectric strength.

[0062] (6) Furthermore, the first insulating layer formation step of Embodiment 1 is configured to include, in this order, a penetration step in which a water-soluble material is permeated into the substrate bundle 30, and a solidification step in which the permeated water-soluble material is solidified. 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. As a result, the dripping and uneven adhesion described in (3) above do not occur, and a homogeneous first insulating layer 50 can be obtained regardless of the part of the coil. As a result, a high-quality coil with homogeneous dielectric strength characteristics and stable insulating properties can be obtained regardless of the part of the coil. Furthermore, forming the first insulating layer using a water-soluble material involves simply immersing the substrate bundle 30 in an aqueous solution containing the water-soluble material, which allows the material that will become the first insulating layer to spread around the substrate 10. This requires fewer steps compared to forming the first insulating layer by coating. Therefore, the coil manufacturing method according to Embodiment 1 not only yields high-quality coils but also improves work efficiency and enables the mass production of coils.

[0063] Furthermore, by performing the step of impregnating 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. In other words, 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. Also, by controlling the applied DC voltage, variations in the film thickness of the first insulating layer 50 can be easily suppressed compared to coating. Moreover, even when manufacturing coils with complex three-dimensional shapes (with uneven surfaces), electrodeposition insulating coating allows for the easy formation of an insulating film (first insulating layer 50) on the coil surface. Therefore, by performing the step of impregnating and solidifying water-soluble materials using electrodeposition insulating coating, it is possible to obtain high-quality coils with excellent mass-producibility while having optimal specifications (film thickness), uniformity, and stable dielectric strength characteristics.

[0064] [Embodiment 2] Figure 5 is a diagram illustrating the coil 102A according to Embodiment 2. Figures 5(a) and 5(b) correspond to Figures 2(a) and 2(b). In Embodiment 2, for components whose basic configuration and characteristics are the same as those in Embodiment 1, the same reference numerals as in Embodiment 1 are used or omitted, and the description of those components is omitted.

[0065] 1. Coil 102A according to Embodiment 2 The coil 102A according to Embodiment 2 has basically the same configuration as the coil 101A according to Embodiment 1, but differs from the coil 101 according to Embodiment 1 in the relationship between the base material 10 and the first insulating layer 50. In other words, as shown in Figure 5(b), the coil 102A according to Embodiment 2 has a first insulating layer 50 integrally formed on each individual base material 10. Specifically, when constructing the base material bundle 30, so-called "magnet wire (no reference numeral)" is used, in which an insulating coating is applied to the base material 10 in advance. A "magnet wire" is a base material such as copper wire to which an insulating coating such as enamel is applied in advance. In the coil 102A according to Embodiment 2, a stranded wire 20, formed by twisting six magnet wires together, is used as an intermediate material, starting from the magnet wire. Three sets of these stranded wires 20 are used to braid and form a braided wire 24. The process of forming the braided wire 24 by constructing the stranded wires 20 is the same as in the coil 101A according to Embodiment 1. The remaining second insulating layer 70 can also be configured in the same way as the second insulating layer 70 of Embodiment 1.

[0066] 2. Manufacturing method of coil 102A according to Embodiment 2 Figure 6 is a manufacturing process diagram illustrating the manufacturing method of coil 102A according to Embodiment 2. For components whose basic configuration and characteristics are the same as those of Embodiment 1, the same reference numerals as in Embodiment 1 are used or omitted, and the description of those components is omitted.

[0067] The method for manufacturing the coil 102A according to Embodiment 2 includes the following steps (a) to (d) in this order. (a) A coated wire preparation step in which an insulating film, which is a first insulating layer 50, is prepared in advance around a base material 10 (magnet wire: no reference numeral), and (b) a base material bundle preparation step in which a base material bundle 30 is prepared by bundling multiple coated wires together (see Figure 6 (i) to (ii)). Note that "bundling" here includes twisting and braiding. Figure 6(i) shows a state in which six coated wires (magnet wires) are twisted together to create a stranded wire 20. Figure 6(ii) shows a state in which three sets of stranded wires 20 are used to create a braided wire 24. This braided wire 24 is used as the base material bundle 30.

[0068] (c) A base material bundle forming step in which the base material bundle 30 is wound around the air core region 90 to form the base material bundle 30 (see Figure 6(iii) and Figure 1(b)), and (d) A second insulating layer forming step in which a second insulating layer 70 made of an insulating material is formed around the winding group 62, which is composed of windings 42a and 42b made of the base material bundle 30 and the first insulating layer 50 (see Figure 6(vi)).

[0069] 3. Effects of the coil 102A and the method for manufacturing the coil according to Embodiment 2 According to the coil 102A of Embodiment 2, since a coated wire (magnet wire) with an insulating coating applied to the base material 10 in advance is used, the coil 102A has a standardized first insulating layer 50, resulting in a high-quality coil with stable insulating properties. Furthermore, according to the manufacturing method of coil 102A in Embodiment 2, since a coated wire (magnet wire) with an insulating film pre-applied to the base material 10 is used, it is possible to obtain a high-quality coil with stable insulating properties having a standardized first insulating layer 50, and the first insulating layer formation step of Embodiment 1 is omitted, enabling the production of coils with high work efficiency and excellent mass productivity.

[0070] Furthermore, the coil 102A and the method for manufacturing the coil according to Embodiment 2 have basically the same configuration as the coil 101A and the method for manufacturing the coil according to Embodiment 1, except for the relationship between the base material 10 and the first insulating layer 50. Therefore, it similarly achieves the effects of the coil 101A and the method for manufacturing the coil according to Embodiment 1.

[0071] [Example of experiment] The inventor conducted experiments on the generation of eddy currents associated with the movement of magnets in electromechanical devices and obtained new insights into coils that suppress the generation of eddy currents, which are described below.

[0072] 1. Experimental Design Figure 7 is a schematic diagram showing the experimental setup in an example experiment. To schematically reproduce the movement of magnets in an electromechanical device, a pendulum-shaped experimental jig was constructed as shown in Figure 7. Specifically, permanent magnets MGa and MGb were attached to 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 pivot shaft AX2. The other end 710a of the rod 710 was connected to a bearing shaft to allow rotation under a low coefficient of friction. Furthermore, the system was configured to place the sample (labeled "Sample" in the figure) directly below the pivot axis AX2. The sample was fixed to the upper surface of a sample fixing stand 740 made of a non-magnetic material, and a gap G was set between the level of the upper surface of the sample and the pair of permanent magnets 730 located at the tip of the pendulum, so that the sample and the pair of permanent magnets 730 would not come into spatial contact.

[0073] 2. Samples and Experimental Methods (1) Sample The sample was basically intended to be a coil, but more specifically, various candidate conductive materials such as base material 10 and base material bundle 30 were considered, and these samples were subjected to the experiment. Specifically, the various materials shown in the second column of the table in Figure 8 (described later) were shaped into a rectangular shape of 30 mm × 10 mm in plan view, and each was prepared as a sample.

[0074] (2) Experimental method First, place the sample corresponding to the experiment number on the sample holder 740. At this time, adjust the position of the sample holder 740 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 Figure 7, so that the height of the center of the permanent magnet pair 730 matches the height of the pivot axis AX2 (i.e., so that the rod 710 is horizontal). Next, release the pendulum. As a result, the permanent magnet pair 730 begins to move in the direction of arrow C0 in Figure 7, and oscillates back and forth, moving alternately in the directions of arrows C1 and C2 directly above the sample. This oscillation is dampened by the resistance between the pendulum and the air, as well as losses mainly due to eddy currents generated as the permanent magnet pair 730 passes near the sample, and eventually stops. Experimental data is obtained by observing this back-and-forth oscillation. The observations include the number of times the pendulum oscillates (the number of times until the pendulum stops; hereinafter simply referred to as the number of oscillating movements) and the oscillation time (the time required until the pendulum stops; hereinafter simply referred to as the oscillation time). Assuming that the greater the number of oscillating movements and / or oscillation time, the less loss due to eddy current generation, it was determined that the greater the number of oscillating movements and / or oscillation time, the less eddy current generation there would be. Although the samples in experiment numbers 6 and 7 are not conductive wires, observations were also performed on them for comparison. Experiments 1 to 7 were conducted using the experimental method described above.

[0075] 3. Experimental Results Figure 8 is a table showing the experimental results in the example experiment. As shown in Figure 8, in experiments 2, 4, and 5, where the average radius of the base material (conductor part) is 100 μm or less, the number of reciprocating motions and vibration time are relatively large, and the generation of eddy currents is small. Furthermore, when the average radius of the base material (conductor part) is 50 μm or less, the generation of eddy currents is even smaller. In addition, in experiments 4 and 5, which are braided wires in which multiple bare conductor wires are braided together, the number of reciprocating motions and vibration time are relatively large, and the generation of eddy currents is small. The magnet wire in experiment 2 (with an insulating coating applied to the conductive base material) also shows a relatively large number of reciprocating motions and vibration time, and the generation of eddy currents is small. Furthermore, the plated copper wire in experiment 3 also shows a relatively large number of reciprocating motions and vibration time, and the generation of eddy currents is small.

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

[0077] [Differentiation] Although the present invention has been described above based on the embodiments described above, the present invention is not limited to the embodiments described above. It can be implemented in various forms without departing from the spirit of the 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 embodiments are illustrative 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 winding can also be changed. Figure 9 is a diagram illustrating coil 103A according to modified example 1. Reference numeral 63 indicates a group of windings. Figures 9(a) and 9(b) correspond to Figures 2(a) and 2(b). In the figures, for components whose basic configuration and characteristics are the same as those of Embodiment 1, the same reference numerals as in Embodiment 1 are used or omitted, and the description of those components is omitted.

[0080] In the description of Embodiment 1, a coil 101 of the type in which windings 41a and 41b are wound around the air core region 90 about 1.75 times and stacked in two stages was illustrated. However, the present invention is not limited thereto. For example, as shown in Figure 9, the coil 103A may be configured with a single-stage winding 43 in which winding 43 is wound around the air core region 90 about 0.75 times (Modification 1).

[0081] (3) Figure 10 is a diagram illustrating coil 104A according to modified example 2. Figures 10(a) and 10(b) correspond to Figures 5(a) and 5(b). Reference numeral 64 indicates a winding group. In the diagram, for components whose basic configuration and characteristics are the same as those of Embodiment 2, the same reference numerals as in Embodiment 2 are used or omitted, and the description of those components is omitted.

[0082] In the description of Embodiment 2, a coil 102A of the type in which windings 42a and 42b are wound around the air core region 90 about 1.75 times and stacked in two stages was illustrated. However, the present invention is not limited thereto. For example, as shown in Figure 10, a coil 104A may be configured with a single stage winding 44, where winding 44 is wound around the air core region 90 about 0.75 times (Modification 2).

[0083] (4) In Embodiment 1, Embodiment 2, Modification 1 and Modification 2, the first insulating layer 50 and the second insulating layer 70 were described assuming that they are made of separate materials (or in the case of the manufacturing method invention, they are made in separate processes). However, the present invention is not limited thereto. Specifically, the first insulating layer 50 and the second insulating layer 70 may be made of the same material (or in the case of the manufacturing method invention, they are made in the same process). For example, the first insulating layer 50 and the second insulating layer 70 may both be made as electrodeposited insulating coatings formed around a base material 10 made of bare conductor wires 12. In the case of the manufacturing method invention, the first insulating layer 50 and the second insulating layer 70 may be made in a single electrodeposited insulating coating.

[0084] (5) In each embodiment, an electromechanical device operating with two-phase excitation has been described as an example. However, the present invention is not limited thereto and can also be applied to, for example, an electromechanical device that is excited with three phases.

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

[0086] 10,910…Base material, 12,912…Bare conductor wire, 20…Stranded 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 section, 82A,82B…Second coil end section, 84A,84B…Effective coil section, 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 sub-assembly, 101BS…Second coil sub-assembly, 710…Rod, 710a…Other end (of the rod), 710b…One end (of the rod), 720…Fixing member, 730…Permanent magnet pair, 740…Sample fixing stand, 914a…Magnet wire, 950…Insulating coating, 950'…Insulating coating layer

Claims

1. An air-core coil arranged along the direction of movement of the magnet in an electromechanical device, A substrate made of a conductive material, A first insulating layer is formed of an insulating material such that, when the coil is cut by a virtual plane perpendicular to the longitudinal direction of the base material and the cut surface is viewed, it is in contact with the base material. When a winding, which is made of an insulating material and is composed of a bundle of multiple such base materials, is cut by a virtual plane perpendicular to the length direction of the winding and the cut surface of the winding is viewed, a second insulating layer is formed around the winding group so as to surround the winding group in which the winding is wound around an air core region, Equipped with, The average radius of the substrate is 100 μm or less. The aforementioned substrate bundle uses a coated wire in which an insulating film as the first insulating layer has been pre-applied to the substrate. The aforementioned base material bundle consists of a braided wire in which a plurality of the aforementioned coated wires are braided together. The plurality of windings extend parallel to each other and have portions in which the plurality of windings contact each other without the second insulating layer in between. A coil characterized by the following features.

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

3. A method for manufacturing a coil according to claim 1 or 2, A winding preparation step involves bundling multiple coated wires together to prepare the winding, A winding forming step in which the winding is wound around the air core region to form the winding, A second insulating layer forming step, in which the second insulating layer made of an insulating material is formed around the winding group so as to surround the winding group made of the windings, A method for manufacturing a coil, characterized by including the following in this order.

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